Technology Developments: the Role of Mechanism and Machine Science and IFToMM

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Technology Developments: the Role of Mechanism and Machine Science and IFToMM

MECHANISMS AND MACHINE SCIENCE Volume 1

Series Editor MARCO CECCARELLI

For other titles published in this series, go to www.springer.com/series/8779

Marco Ceccarelli Editor

Technology Developments: the Role of Mechanism and Machine Science and IFToMM

Editor Marco Ceccarelli Dipto. Meccanica, Strutture, Ambiente e Territorio (DiMSAT) Università Cassino Lab. Robotica e Meccatronica (LARM) Via G. di Biasio 43 03043 Cassino Italy [email protected]

ISSN 2211-0984 e-ISSN 2211-0992 ISBN 978-94-007-1299-7 e-ISBN 978-94-007-1300-0 DOI 10.1007/978-94-007-1300-0 Springer Dordrecht Heidelberg London New York Library of Congress Control Number: 2011928246 © Springer Science+Business Media B.V. 2011 No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

Preface

This is the first book of a series that will be focused on MMS (Mechanism and Machine Science). What is better to start a new book series on MMS by describing activity on MMS by the international community referring to it? This is one of main motivations for this book that presents also IFToMM, the international Federation on the Promotion of MMS and its activity. IFToMM is the unique worldwide institution in the area if Mechanical Engineering addressing specifically to MMS. With its 44 member organizations it is present in all the continents and its activity that is ran usually in international frames but not only, is visible worldwide. Indeed this book has been scheduled also within a IFToMM Presidency program ‘Visibility + Activity’ for reinvigorating the significance of IFToMM because of its mission in collaboration and development for MMS promotion. Visibility is aimed at showing clearly the activity of IFToMM and therefore its significance in promoting MMS in all its aspects for formation, research, innovation, and professional application. Activity is linked to the Visibility aim but it is clearly focused in advancing all the fields of MMS and in facilitating international collaborations among institutions, professional entities, and individuals within the above mentioned aspects. IFToMM activity consists mainly of forums and meetings both in scientific and professionals frames, at international but also national and local levels, in editorial works reporting last advances but also disseminating fundamentals and achievements in MMS. Thus, this book can be considered in the aims both of Visibility and Activity, since its goals have been planned for presenting MMS and IFToMM to a wider public in Engineering Science. As a reader can appreciate, the content of the book gives also a view of how technical works in MMS have been and still are influential in Technology developments for Society benefits. The book is organized with contribution by IFToMM officers being Chairs of member organizations (MOs), permanent commissions (PCs), and technical committees (TCs), who have reported their experiences and views toward the future of IFToMM and MMS. In fact, the book is composed of three chapters, namely the first one with general considerations by high-standing IFToMM persons, the second chapter with views by the chairs of PCs and TCs as dealing with specific subject areas, and the third

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one with reports by the chairs of MOs as presenting experiences and challenges in national and territory communities. Therefore the book can be of interest to a wide public in order to know the status and trends in MMS both at international level through IFToMM and in national/ local frames through the leading actors of activities. In addition, the book can be considered also a fruitful source for who-is-who in MMS, historical backgrounds and trends in MMS developments, as well as for challenges and problems in future activity by IFToMM community and in MMS at large. This volume has been possible thanks to the invited authors, who have enthusiastically shared this initiative and who have spent time and efforts in preparing the papers with care and transmitting their passion for engineering science and international collaboration. I believe that readers will take advantage of the papers in this book and future ones by supplying further satisfaction and motivation for her or his work with interdisciplinary activity for engineering developments. I am grateful to the authors of the articles for their valuable contributions and for preparing their manuscripts on time. Also acknowledged is the professional assistance by the staff of Springer Science + Business Media and especially by Miss Anneke Pot and Dr Nathalie Jacobs, who have enthusiastically supported this book project with their help and advices. I am grateful to my family: my wife Brunella, daughters Elisa and Sofia, and son Raffaele for their encouragement and support with their patience and understanding, without which the organization of such a task with so many people from different fields might be impossible. Cassino, Italy

Marco Ceccarelli Editor

Contents

Part I  General Considerations Activity and Trends in MMS from IFToMM Community........................... Marco Ceccarelli

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Promoting Novel Approaches of MMS for Sustainable Energy Applications......................................................................................... Ion Visa

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Role of MMS and IFToMM in Iberoamerican Community and Open Perspectives . .................................................................................. Emilio Bautista Paz and Justo Nieto Nieto

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India’s Contributions over the Last 40 Years in Turbine Blade Dynamics................................................................................................ Jammi S. Rao

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A Brief History of Legged Robotics............................................................... P.J. Csonka and K.J. Waldron

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Part II Viewpoints by Chairs of IFToMM Technical Committees and Permanent Commissions The History of Mechanism and Machine Science (HMMS) and IFToMM’s Permanent Commission for HMMS.................................... Teun Koetsier, Hanfried Kerle, and Hong-Sen Yan

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On the Development of Terminology and an Electronic Dictionary for Mechanism and Machine Science............................................................. A.J. Klein Breteler

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The Role of Mechanism Models for Motion Generation in Mechanical Engineering............................................................................. 107 Hanfried Kerle, Burkhard Corves, Klaus Mauersberger, and Karl-Heinz Modler Development of Computational Kinematics Within the IFToMM Community....................................................................................................... 121 Doina Pisla and Manfred L. Husty Theory and Practice of Gearing in Machines and Mechanisms Science................................................................................. 133 Veniamin I. Goldfarb ThinkMOTION: Digital Mechanism and Gear Library Goes Europeana............................................................................................... 141 Burkhard Corves, Torsten Brix, and Ulf Döring Micromachines: The Role of the Mechanisms Community......................... 153 G.K. Ananthasuresh Role of MMS and IFToMM in Multibody Dynamics................................... 161 Javier Cuadrado, Jose Escalona, Werner Schiehlen, and Robert Seifried State-of-the-Art and Trends of Development of Reliability of Machines and Mechanisms......................................................................... 173 Irina V. Demiyanushko Role of MMS and IFToMM in Robotics and Mechatronics........................ 185 I.-Ming Chen Role of MMS and IFToMM in the Creation of Novel Automotive Transmissions and Hybrids............................................................................. 191 Madhusudan Raghavan Advancements and Future of Tribology from IFToMM.............................. 203 Jianbin Luo Part III  Experiences and Views by IFToMM Member Organizations MMS and IFToMM in Armenia: Past, Present State and Perspectives............................................................................................... 223 Yuri Sarkissyan Role of MMS and IFToMM in Belarus.......................................................... 235 Vladimir Algin

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The Role of ABCM in Engineering and Mechanical Sciences in Brazil and Its Relationship with IFToMM................................................ 249 João Carlos Mendes Carvalho Contributions to the Promotion of Mechanism and Machine Science by the IFToMM Canadian Community (CCToMM).................................... 257 M.J.D. Hayes, R. Boudreau, J.A. Carretero, and R.P. Podhorodeski Some Recent Advances in Mechanisms and Robotics in China–Beijing.............................................................................................. 265 Tian Huang Development of Mechanism, Machine Science and Technology in Taiwan............................................................................... 281 Hong-Sen Yan, Zhang Hua Fong, Ying Chien Tsai, Cheng Kuo Sung, Jao Hwa Kuang, Chung Biau Tsay, Shyi Jeng Tsai, Dar Zen Chen, Tyng Liu, Jyh Jone Lee, and Shuo Hung Chang Czech Contribution to the Role of Mechanism and Machine Science and IFToMM....................................................................................... 289 Miroslav Václavík, Ladislav Půst, Jaromír Horáček, Jiří Mrázek, and Štefan Segľa Role of MMS in the Development of Mechanical Engineering Research in Georgia......................................................................................... 295 Nodar Davitashvili The Role of MMS (Mechanism and Machine Science) and IFToMM in Greece................................................................................... 301 Thomas G. Chondros MMS at University Level in Hungary Within the IFToMM Community....................................................................................................... 315 Elisabeth Filemon Developments in the Field of Machines and Mechanisms in India over the Ages...................................................................................... 327 C. Amarnath The Influence of IFToMM and MMS in Present Day Italian Culture.................................................................................................. 337 Alberto Rovetta Achievements in Machine Mechanism Science in Lithuania....................... 343 Vytautas Ostasevicius

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The Mexican Contribution to Mechanism and Machine Science and Technology................................................................................... 353 Ricardo Chicurel-Uziel, Alberto Caballero-Ruiz, Leopoldo Ruiz-Huerta, and Alfonso Pámanes-García The Significance and Role of IFToMM Poland in the Creative Development of Mechanism and Machine Science....................................... 367 Józef Wojnarowski The Romanian Association for Mechanisms and Machines Science – Past, Present and Future................................................................. 383 Ion Visa Formation and Development of MMS in Russia with Participation of Russia in IFToMM Activity........................................................................ 395 Nikolay V. Umnov and Victor A. Glazunov Role of MMS and IFToMM in Slovakia........................................................ 415 S. Segla and P. Solek The Role of MMS and IFToMM Influence in Spain..................................... 427 Fernando Viadero, Vicente Díaz, A. Fernández, and Y.A. Gauchía Ultra-High Precision Robotics: A Potentially Attractive Area of Interest for MM and IFToMM................................................................... 439 Clavel Reymond, Le Gall Bérangère, and Bouri Mohamed Teaching and Research in Mechanism Theory and Robotics in Tunisia................................................................................... 451 Lotfi Romdhane and A. Mlika Contributions to MMS and IFToMM from USA . ....................................... 461 Kenneth J. Waldron Author Index.................................................................................................... 477

Contributors

Vladimir Algin The Belarusian Committee of IFTOMM, The National Academy of Sciences of Belarus,12 Akademicheskaya Str., 220072 Minsk, Belarus [email protected]; [email protected] C. Amarnath Department of Mechanical Engineering, IIT Bombay, Powai, Mumbai 400 076, India [email protected]; [email protected] G.K. Ananthasuresh Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560012, India [email protected] Le Gall Bérangère Laboratoire de Systèmes Robotiques (LSRO), Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Institute of Technology, Station 9, CH - 1015 Lausanne, Switzerland R. Boudreau Université de Moncton, Moncton, NB E1A 3E9, Canada A.J. Klein Breteler Faculty OCP/Mechanical Engineering, University of Technology Delft, Mekelweg 2, Delft 2628 CD, The Netherlands [email protected] Torsten Brix TUI University of Ilmenau, Ilmenau, Germany

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Alberto Caballero-Ruiz Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Coyoacán 04510, México D.F., Mexico J.A. Carretero University of New Brunswick, New Brunswick E2L 4L5, Canada João Carlos Mendes Carvalho School of Mechanical Engineering, Federal University of Uberlândia, Campus Santa Mônica, 38400-902 Uberlândia, Minas Gerais, Brazil [email protected] Marco Ceccarelli Laboratory of Robotics and Mechatronics, DIMSAT, University of Cassino, Via Di Biasio 43, Cassino 03043, Italy [email protected] Shuo Hung Chang National Taiwan University, Taipei, Taiwan and Department of Mechanical Engineering, National Taiwan University, 1, Sec. 4, Roosevelt Rd., Taipei, Taiwan [email protected] I.-Ming Chen School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore 639798, Singapore [email protected] Dar Zen Chen National Taiwan University, Taipei, Taiwan Ricardo Chicurel-Uziel Instituto de Ingeniería, Universidad Nacional Autónoma de México, Apartado Postal 70-472, Coyoacán 04510, México D.F., Mexico [email protected] Thomas G. Chondros Mechanical Engineering and Aeronautics Department, School of Engineering, University of Patras, Patras 265 00, Greece [email protected]

Contributors

Burkhard Corves R.-W. Technische Hochschule Aachen, Eilfschornsteinstrasse 18, Aachen D 52056, Germany [email protected] P.J. Csonka Robotic Locomotion Laboratory, Stanford University, Stanford, CA, USA Javier Cuadrado University of La Coruña, Ferrol, Spain [email protected] Nodar Davitashvili Georgian Committee of IFToMM, Georgian Technical University, 77, M. Kostava str., 0175 Tbilisi, Georgia [email protected] Irina V. Demiyanushko Moscow Auto-Road, State Technical University (MADI), 64, Leningradskiy prospect, Moscow 125190, Russia [email protected] Vicente Díaz Mechanical Engineering Department, Carlos III University of Madrid, Madrid, Spain Ulf Döring TUI University of Ilmenau, Ilmenau, Germany Jose Escalona Escuela de Ingenieros, Dept. Ingeniería Mecánica y de los Materiales, University of Seville, Camino de los Descubrimientos s\n, 41092 Sevilla, Spain A. Fernández Structural and Mechanical Engineering Department, University of Cantabria, Santander, Spain Elisabeth Filemon Department of Applied Mechanics, Budapest University of Technology and Economics (TUB), 1111-Budapest Muegyetem rkp. 3. Hungary [email protected] Zhang Hua Fong National Chung Cheng University, Chiayi, Taiwan

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Y.A. Gauchía Mechanical Engineering Department, Carlos III University of Madrid, Madrid, Spain Victor A. Glazunov Mechanical Engineering Research Institute, Russian Academy of Sciences, Moscow, Russia Veniamin I. Goldfarb Department of Production Engineering, Institute of Mechanics, Izhevsk State Technical University, Studencheskaya str. 7, Izhevsk 426069, Russia [email protected] M.J.D. Hayes Department of Mechanical & Aerospace Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada [email protected] Jaromír Horáček Institute of Thermomechanics, Czech Academy of Sciences, Prague, Czech Republic Tian Huang Department of Mechatronical Engineering, Tianjin University, Tianjin 300072, P.R. China [email protected] Manfred L. Husty Institute of Basic Science in Engineering, University Innsbruck, Unit Geometry and CAD, Technikerstraße 13, Innsbruck A-6020, Austria [email protected] Hanfried Kerle Institut für Werkzeugmaschinen und Fertigungstechnik, TU Braunschweig, Langer Kamp 19b, D-38106 Braunschweig, Germany and TU Braunschweig, Peterskamp 12, Braunschweig D-38108, Germany [email protected]; [email protected] Teun Koetsier Department of Mathematics, FEW, VU University Amsterdam, De Boelelaan 1081, NL-1081HV, Amsterdam, The Netherlands [email protected]

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Jao Hwa Kuang National Sun Yat-Sen University, Kaohsiung, Taiwan Jyh Jone Lee National Taiwan University, Taipei, Taiwan Tyng Liu National Taiwan University, Taipei, Taiwan Jianbin Luo State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China [email protected] Klaus Mauersberger TU Dresden, Dresden, Germany A. Mlika Laboratoire de Génie Mécanique, Ecole Nationale d’Ingénieurs de Sousse, 5019 Monastir, Tunisia Karl-Heinz Modler TU Dresden, Dresden, Germany Bouri Mohamed Laboratoire de Systèmes Robotiques (LSRO), Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Institute of Technology, Station 9, CH - 1015 Lausanne, Switzerland reymond.clavel@epfl,ch Jiří Mrázek Department of Textile Machine Design, Technical University of Liberec, Liberec 1, Czech Republic Justo Nieto Nieto Technical University of Valencia, Valencia, Spain [email protected] Vytautas Ostasevicius Kaunas University of Technology, Studentu st. 65, LT – 51369 Kaunas, Lithuania [email protected] Emilio Bautista Paz Escuela Superior De Ingenieros Industriales, Departamento De Ingeniería Mecánica Y Fabricación, Universidad Politécnica De Madrid, José Gutiérrez Abascal, 2, Madrid 28006, Spain

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and Technical University of Madrid, Madrid, Spain [email protected] Alfonso Pámanes-García Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Coahuila, Carretera Matamoros Km. 7.5, Ciudad Universitaria, C.P. 27276 Torreón, Coahuila, Mexico Doina Pisla Department of Mechanics and Computer Programming, Technical University of Cluj-Napoca, Memorandumului 28, 400114 Cluj-Napoca, Romania and Technical University of Cluj-Napoca, Memorandumului 28, 400114 Cluj-Napoca, Romania [email protected]; [email protected] R.P. Podhorodeski University of Victoria, Victoria, BC V8N 1M5, Canada Ladislav Půst Institute of Thermomechanics, Czech Academy of Sciences, Prague, Czech Republic Madhusudan Raghavan Hybrid Systems, Propulsion Systems Research Lab, GM R&D Center, 30500 Mound Road, Warren, MI 48090-9055, USA and 6816 Trailview Court, West Bloomfield, MI 48322, USA [email protected] Jammi S. Rao Rotor Dynamics Technical Committee, Altair Engineering India Pvt Ltd, 5th Floor Mercury Building, Prestige Tech Park, Marathhalli-Sarjapur Ring Road, Bangalore, Karnataka 560103, India [email protected]; [email protected] Clavel Reymond Laboratoire de Systèmes Robotiques (LSRO), Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Institute of Technology, Station 9, CH - 1015 Lausanne, Switzerland [email protected]

Contributors

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Lotfi Romdhane Laboratoire de Génie Mécanique, Ecole Nationale d’Ingénieurs de Sousse, 5019 Monastir, Tunisia [email protected] Alberto Rovetta Dipartimento di Meccanica, Politecnico di Milano, Via Lamasa 34, 20156, Milan, Italy [email protected] Leopoldo Ruiz-Huerta Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Coyoacán 04510, México D.F., Mexico Yuri Sarkissyan Armenian IFToMM Committee, State Engineering University of Armenia, 105 Teryan str., Yerevan 375009, Armenia [email protected] Werner Schiehlen University of Stuttgart, Stuttgart, Germany Štefan Segľa Department of Applied Mechanics, Technical University of Liberec and VÚTS Liberec, Plc., Czech Republic S. Segla Department of Mechanics, Faculty of Mechanical Engineering, Slovak National Committee of IFToMM, Technical University of Liberec, Studentska 2, 46117 Liberec, Czech Republic [email protected] Robert Seifried University of Stuttgart, Stuttgart, Germany P. Solek Department of Mechanics, Faculty of Mechanical Engineering, Slovak National Committee of IFToMM, Technical University of Liberec, Studentska 2, 46117 Liberec, Czech Republic [email protected] Cheng Kuo Sung National Tsing Hua University, Hsinchu, Taiwan

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Contributors

Ying Chien Tsai Cheng Shiu University, Kaohsiung, Taiwan Shyi Jeng Tsai National Central University, Jhongli, Taiwan Chung Biau Tsay Minghsin University, Hsinchu, Taiwan Nikolay V. Umnov Mechanical Engineering Research Institute, Russian Academy of Sciences, Moscow, Russia [email protected] Miroslav Václavík Department of Applied Mechanics, Technical University of Liberec and VÚTS Liberec, Plc., Czech Republic and VÚTS, a.s., U Jezu 525/4, 461 19 Liberec 1, Czech Republic [email protected] Fernando Viadero Structural and Mechanical Engineering Department, University of Cantabria, Santander, Spain [email protected] Ion Visa Transilvania University of Brasov, Eroilor Bd., 29, Brasov 500036, Romania [email protected] Kenneth J. Waldron Department of Mechanical Engineering, Stanford University, Terman Engineering 521, Stanford, CA, 94305-4021, USA [email protected] Józef Wojnarowski Silesian University of Technology, ul.Konarskiego 18A, Gliwice 44-100, Poland [email protected] Hong-Sen Yan Department of Mechanical Engineering, National Cheng Kung, University, 1, University Road, Tainan 701-01, Taiwan [email protected]

Part I

General Considerations

Activity and Trends in MMS from IFToMM Community Marco Ceccarelli

Abstract  Mechanism and Machine Science (MMS) has been the core of mechanical engineering, and indeed of industrial engineering, since the beginning of engineering practice and particularly in modern times. A short survey is presented to outline the main characteristics of mechanisms and their evolution with the aim to identify challenges and the role of MMS in future developments of Technology for the benefit of Society. The significance of IFToMM, the International Federation for the Promotion of MMS, is also stressed as the worldwide community that in the past 40 years has contributed the most to aggregate common views and developments with an important role for future improvements yet to come. Modern systems specifically with mechatronic design and operation still need careful attention from mechanism design viewpoints to properly achieve the goals of forwarding technological developments for supporting or replacing human operators in their activity.

Introduction In this survey a vision is outlined together with a brief historical perspective in order to show that, although the treatment of many new issues in Mechanism and Machine Science (MMS) can be based on fundamental concepts that were developed in the past, we are still faced with several challenging issues that need to be tackled to achieve proper solutions to new and updated MMS problems in continually evolving Technology also for the benefit of Society. New systems and updated performance are constantly being required for mechanism applications that now need special attention, starting from previously existing theoretical bases and aiming to update or conceive of new algorithms for their designs and/or operations with optimal characteristics. M. Ceccarelli (*) Laboratory of Robotics and Mechatronics, DIMSAT, University of Cassino, Via Di Biasio 43, Cassino 03043, Italy e-mail: [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_1, © Springer Science+Business Media B.V. 2011

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Two main considerations can be observed in order to claim that MMS is still a necessary discipline that continues to require a wide efforts in teaching, research, and practice, namely they are: –– Human beings operate and interact with their environment and many systems on the basis of actions of a mechanical nature; therefore mechanisms will always be an essential part of systems that assist or substitute for human beings in their actions and other operational tasks. –– There is an increasing complexity in problems facing society and in the nature of solutions to those problems. Thus mechanisms must be updated based on discovery of new knowledge, means and applications of both old and new mechanisms. A historical insight can be useful both to understand past developments and to recognize new trends and open problems as determined by changing conditions in society and technological capability. Historical backgrounds and developments have been discussed from a number of technical viewpoints (also in surveys of the History of Science) in several works that aim to track the historical evolution of Technology and Engineering, and to recognize the original paternity of machine achievements, such as for example in [1–12] just to cite a few relevant sources in reasonably accessible literature. Recently a specific conference forum has been established within IFToMM (The International Federation for the Promotion of MMS) as the HMM (History of Machines and Mechanisms) Symposium in which a number of views and studies are discussed [13–15]. Also some more specific technical emphasis has been placed on historical trends in recent research activity in papers such as [41– 44]. Even the present author has attempted to outline historical developments with the aim of tracking the past to identify directions for future work in [14, 16–19, 35– 40]. In this paper, a description of the role of MMS and IFToMM in technological developments is presented through historical outlines and general considerations based on the author’s experience. The rapid developments in Technology together with changes in Society have made it difficult to recognize the significant role that MMS has played in the past, thus calling for stronger efforts by the IFToMM community to advocate for MMS and to firmly delineate for it a more positive role in the future.

An Historical Outline of Progress Towards MMS Over time the changes of needs and task requirements in Society and Technology have required continuous evolution of mechanisms and their uses, with or without a rational technical awareness. In past evolution, technical knowledge has made possible the proposal of more and more solutions enhancing mechanisms and their uses in order to satisfy the demands with updated aspects coming from Technology and Society.

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Mechanisms and machines have attracted attention since the beginning of Technology and they have been studied and designed with successful activity and specific results. But TMM (Theory of Machines and Mechanisms) has reached maturity as an independent discipline only in the nineteenth century. Today we refer to TMM as MMS since a wider engineering area can be identified for interest and application of the mechanism concept. The historical developments of mechanisms and machines can be divided into periods with specific technical developments that, according to the present author’s personal opinion, can be identified and characterized by referring to significant milestones such as: • Utensils in Prehistory • Antiquity: 5th cent. BCE (Mechanos in Greek theater plays) • Middle Ages: 275 CE (sack of the School of Alexandria and destruction of Library and Academy) • Early design of machines: 1420 CE (the book Zibaldone with designs by Filippo Brunelleschi) • Early discipline of mechanisms: 1577 CE (the book Mechanicorum Liber by Guidobaldo Del Monte) • Early Kinematics of mechanisms: 1706 CE (the book Traitè des Roulettes by Philippe De La Hire) • Beginning of TMM: 1794 CE (Foundation of Ecole Polytechnique) • Golden Age of TMM: 1841 CE (the book Principles of Mechanism by Robert Willis) • World War I Period: 1917 CE (the book Getriebelehre by Martin Grübler) • Modern TMM: 1959 CE (the journal paper Synthesis of Mechanisms by means of a Programmable Digital Computer by Ferdinand Freudenstein and Gabor N. Sandor) • MMS Age: 2000 CE (re-denomination of TMM to MMS by IFToMM) The historical evolution to the current MMS can be briefly outlined by looking at developments that have occurred since the Renaissance period. Mechanisms and machines were used and designed as a means to achieve and improve solutions in various fields of human activity. Specific fields of mechanisms grew in results and awareness, and the first personalities were recognized as brilliant experts, such as for example Francesco Di Giorgio Martini and Leonardo Da Vinci amongst many others, as emphasized also with social reputation in [39]. At the end of the Renaissance period the Mechanics of Machinery attracted great attention also in the Academic world, starting from the first classes given by Galileo Galilei in 1593– 1598 [20]. In the eighteenth century the designer figure evolved to have a professional status with strong theoretical bases, finalizing a process that in the Renaissance saw the activity of closed small communities of pupils/co-workers after ‘mastros’ and ‘maestros’. Academic activity increased basic knowledge for the rational design and operation of mechanisms. The first mathematizations were attempted and fundamentals on mechanism kinematics were proposed by the pioneering investigators, who were specifically dedicated to mechanism issues,

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such as for example Philippe De la Hire amongst many others. The successful practice of mechanisms was fundamental for relevant developments in the Industrial Revolution during which many practitioners and researchers implemented the evolving theoretical knowledge in practical applications and new powered machines. The nineteenth century can be considered the Golden Age of TMM since relevant novelties were proposed both in theoretical and practical fields. Mechanisms formed the core element of any machinery and any technological advance at that time. A community of professionals was identified and specific academic formation was established worldwide. TMM gained an important role in the development of Technology and Society and several personalities expressed the fecundity of the field with their activity, such as for example Franz Reuleaux amongst many others. The first half of the twentieth century saw the prominence of TMM in mechanical (industrial) engineering but with more and more integration with other technologies. A great evolution was experienced when with the advent of Electronics it was possible to handle contemporaneously several motors in multi-d.o.f. applications of mechanisms and to operate 3D tasks with spatial mechanisms. The increase of performance (not only in terms of speed and accuracy) required more sophisticated and accurate calculations that became possible with the advent of an Informatics approach (involving computers and programming strategies). Technically, MMS can be viewed as an evolution of TMM having a broader content and vision of a Science, including new disciplines. Historically, TMM has included as its main disciplines: History of TMM; Mechanism Analysis and Synthesis; Theoretical Kinematics; Mechanics of Rigid Bodies; Mechanics of Machinery; Machine Design; Experimental Mechanics; Teaching of TMM; Mechanical Systems for Automation; Transportation Machinery, Control and Regulation of Mechanical Systems; RotorDynamics; Human-Machine Interfaces; and BioMechanics. The modernity of MMS has augmented TMM with new vision and means but also with many new disciplines, of which the most significant can be recognized as: Robotics; Mechatronics; Computational Kinematics; Computer Graphics; Computer Simulation; CAD/CAM for TMM; Tribology; Multibody Dynamics, Medical Devices, and Service Systems. In 2000 the evolution of the name from TMM to MMS brought also a change in the denomination of the IFToMM Federation from “IFToMM: the International Federation for TMM” to “IFToMM, the International Federation for the Promotion of MMS”, [27]. This can be considered as due to an enlargement of technical fields into an Engineering Science together with a great success in research and practice of TMM with a corresponding increase of the engineering community worldwide. Today, a modern machine is a combination of systems of different natures and this integration has led to the modern Mechatronics concept, Fig. 1. Thus, most of the recent advances in machinery are considered to be in fields other than MMS. But Mechanism Design can still be recognized as a fundamental aspect for developing successful systems that operate in the mechanical world of human beings. Tasks and systems for human beings must generally have a mechanical nature and a careful Mechanism Design is still fundamental in obtaining systems that assist or substitute for human beings in their operations. Most of those tasks are already performed

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Fig. 1  A scheme for the concept of mechatronics

with mechanism solutions that can be seen as traditional successful ones that nevertheless could benefit from further update or re-consideration because of new operational strategies and/or new materials and components (scaled designs). Therefore, Mechanism Design can still be considered as an engineering area for current research interests. But, what are the open problems and challenges for today’s MMS? Can they be considered as new issues or should they be rediscovered from past ideas?

A Short History of IFToMM The names of IFToMM, TMM, and MMS are related to fields of Mechanical Engineering concerned with Mechanisms in a broad sense. TMM is often misunderstood even in the IFToMM Community, although it is recognized as the specific discipline of Mechanical Engineering related with mechanisms and machines, as commented even in [21] announcing the birth of IFToMM. The meaning of TMM, now MMS, can be clarified by looking at IFToMM terminology [22, 23]: –– Machine: mechanical system that performs a specific task, such as the forming of material, and the transference and transformation of motion and force. –– Mechanism: system of bodies designed to convert motions of, and forces on, one or several bodies into constrained motions of, and forces on, other bodies. The meaning for the word “Theory” needs further explanation. The Greek word for “Theory” (qewrίa) comes from the corresponding verb, whose main semantic meaning is related both with examination and observation of existing phenomena. But, even in the classic Greek language the word theory includes practical aspects of observation as experiencing the reality of the phenomena, so that theory means also practice of analysis results. In fact, this last aspect is what was included in the discipline of modern TMM when Gaspard Monge (1746–1818) established it in the Ecole Polytechnique at the beginning of the nineteenth century [2] (see for example the book by Lanz and Betancourt [24], whose text includes early synthesis procedures and hints for practical applications). Later (see for example Masi [25]) and

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even today (see for example Uicker et al. [26]) many textbooks have been entitled “Theory of Mechanisms” since they describe both the fundamentals and the applications of mechanisms in machinery. The term MMS has been adopted within the IFToMM Community since the year 2000 after a long discussion (see Ceccarelli [27] in the IFToMM Newsletter), with the aim to give a better identification of the modern enlarged technical content and broader view of knowledge and practice with mechanisms. Indeed, the use of the term MMS has also stimulated an in-depth revision in the IFToMM terminology since the definition of MMS has been given as [23]: –– Mechanism and Machine Science: Branch of science, which deals with the theory and practice of the geometry, motion, dynamics, and control of machines, mechanisms, and elements and systems thereof, together with their application in industry and other contexts, e.g., in Biomechanics and the environment. Related processes, such as the conversion and transfer of energy and information, also pertain to this field. The developments in TMM have stimulated cooperation around the world at various levels. One of the most relevant results has been the foundation of IFToMM in 1969, Fig. 2. IFToMM was founded as a Federation of territorial organizations but as based on the activity of individuals within a family frame with the aim to facilitate co-operation and exchange of opinions and research results in all the fields of TMM as stressed in [21]. Many individuals have contributed and still contribute to the success of IFToMM and related activity, (see IFToMM webpage: www. iftomm.org) under a coordination of IFToMM Presidents over time. IFToMM was founded as the International Federation for the Theory of Mechanisms and Machines in Zakopane, Poland on September 29, 1969 during the Second World Congress on TMM (Theory of Mechanisms and Machines). The main promoters of the IFToMM World Federation were Academician Ivan I. Artobolevski (USSR) and Prof. Erskine F.R. Crossley (USA), whose principal aim was to bypass the obstacles of the time of the Cold War in developing international collaboration in TMM science for the benefit of the world society. IFToMM started as a family of TMM scientists among whom we may identify the IFToMM founding fathers, who signed or contributed to the foundation act with the initial 13 Member Organizations, referring to the persons: Academician Ivan I. Artobolevski (USSR), Prof. Erskine F.R. Crossley (USA), Prof. Mikail Konstantinov (Bulgaria), Dr. Werner Thomas (GFR), Prof. B.M. Belgaumkar (India), Prof. Kenneth H. Hunt (Australia), Prof. Jan Oderfeld (Poland), Prof. Jack Phillips (Australia), Prof. George Rusanov (Bulgaria), Prof. Wolfgang Rössner (GDR), Prof. Zènò Terplàn (Hungary),

Fig. 2  The foundation of IFToMM, the International Federation for the Theory of Machines and Mechanisms, in Zakopane (Poland) on 27 September 1969, (Courtesy of IFToMM Archive): (a) the foundation act. (b) A historical moment in which one can recognize: 1 prof. Ivan Ivanovic Artobolevskii (USSR), 2 Prof. Adam Morecki (Poland), 3 Prof. Kurt Luck (Germany), 4 Prof. Mikail Konstantinov (Bulgaria), 5 Prof. Nicolae I. Manolescu (Romania), 6 Prof. Erskine F. Crossley (USA), 7 Prof. Giovanni Bianchi (Italy), 8 Prof. Aron E. Kobrinskii (USSR), 9 Prof. Werner Thomas (Germany), 10 Prof. Jan Oderfeld (Poland)

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Prof. Jammi S. Rao (India), Prof.Giovanni Bianchi (Italy), Prof. Adam Morecki (Poland), Nicolae I. Manolescu (Romania), Leonard Maunder (UK), Douglas Muster (USA), Ilic Branisky (Yugoslavia). The foundation of IFToMM was the result of an intense activity for stimulating and promoting international collaboration, more than what had been done previously, and the process started in the late 1950s, as documented by several letters that are stored in the IFToMM Archive at CISM in Udine, Italy. A first World Congress on TMM (Theory of Mechanisms and Machines) was held in 1965 in Varna, Bulgaria during which the foundation of IFToMM was planned as later it was agreed during the Second World Congress on TMM in Zakopane, Poland. The Congress series was immediately recognized as the IFToMM World Congresses and in 2007 we have celebrated the 12th event with the participation of delegates from 48 Member Organizations and from more than 55 countries. IFToMM activity has grown in many aspects, as for example concerning the number of member organizations (from the 13 founder members to the current 47  members), the size and scale of conference events (with many other conferences, even on specific topics, at national and international levels, in addition to the MMS World Congress), and the number and focus of technical committees working on specific discipline areas of MMS (currently 13, with 2 more to be established). IFToMM was founded in 1969 and today a third generation of IFToMMists is active, who can be named as those working within the IFToMM community. Knowing the History of IFToMM and how we arrived at today’s modus operandi gives a greater awareness of community identity and significance. The IFToMM community evolved in character from that of a family of a few enthusiastic pioneers/visionaries and founders into a scientific worldwide community through the following generations: • 1950s–1979 First generation: founding fathers and their friendly colleagues up to the fourth IFToMM World Congress in Newcastle-upon-Tyne in 1975 with Prof. L. Maunder as Congress Chair • 1980–1995 Second Generation: students and people educated by founding fathers and their friendly colleagues; up to the ninth World Congress in Milan in 1995 with Prof. A. Rovetta as Congress Chair • 1996-today Third Generation: educated people in the frame of IFToMM and within IFToMM activity with 47 organizations as IFToMM members. IFToMM officers (who are the Chairs of IFToMM Member Organizations, the Chairs of TCs and PCs, and the members of the Executive Council) have contributed and still contribute as leaders for the mission of IFToMM, which is stated in the first article of the Constitution as: ‘The mission of IFToMM is the promotion of Mechanism and Machine Science’. A complete list of IFToMM officers over time is available in the Proceedings of the second International Symposium on History of Machines and Mechanisms HMM2004 that was published in 2004 by Kluwer/ Springer, [14], and is now available also in the IFToMM webpage. In particular, Presidents and Secretaries General have had significant roles in guiding the growth and success of IFToMM. Their personalities are also representative

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of the IFToMM community in terms of reputation and visibility worldwide. The Presidents were Ivan I. Artobolevsky (1969–1971 and 1972–1975) (USSR), Leonard Maunder (1976–1979) (UK), Bernard Roth (1980–1983) (USA), Giovanni Bianchi (1984–1987 and 1988–1991) (Italy), Adam Morecki (1992–1995) (Poland), Jorge Angeles (1996–1999) (Canada), Kenneth J. Waldron (2000–2003 and 2004– 2007) (USA), and Marco Ceccarelli (2008–2011) (Italy). The Secretaries General were Mikail Konstantinov (Bulgaria), Emil Stanchev (Bulgaria), Adam Morecki (Poland), Elizabeth Filemon (Hungary), L. Pust (CSSR), Tatu Leinonen (Finland), Marco Ceccarelli (Italy). Details of the History of IFToMM can be found in the first Chapter of the Proceedings of the first International Symposium on History of Machines and Mechanisms HMM2000 (that was published by Kluwer) in which all the past IFToMM Presidents have outlined their historical perspective of IFToMM in contributed papers with references, [28]. Additional references can be indicated as [3, 18, 29–33, 42]. More information on IFToMM and its activity can be found in the website: http://www.iftomm.org.

Trends and Challenges in MMS The main current interests for research in MMS as trends and challenges can be summarized in the following topics: –– –– –– –– –– –– –– –– –– –– ––

3D Kinematics and its application in practical new systems and methodologies Modeling and its mathematization Multi-d.o.f. multibody systems Spatial mechanisms and manipulators Unconventional mechanisms (with compliant, underactuated, overconstrained and other structures) Scaled mechanisms Tribology issues Creative design Mechatronic designs Human-machine interactions for user friendly oriented systems Reconsideration and reformulation of theories and mechanism solutions

Those topics and many others in MMS are also motivated by needs for the formation and activity of professionals, who will be able to conceive and transmit innovation both into production and service frames. Teaching in MMS requires attention to modern methodologies that can efficiently use computer and software means, which are still evolving rapidly. Thus, there is a need to update also the teaching means that makes use of simulations and computer oriented formulation. In addition, mechatronic layout of modern machinery suggests that mechanisms should be taught as integrated with other components like actuators and sensors since the beginning of the formation of curricula.

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The academic teaching mission needs to be revitalized and better understood as a result of high expertise of teachers that can be reached also with intense research activity and links to the professional and industrial world. This requires more attention and vision not only from the academy but mainly from society as a whole that through governing leaders should give more and more support to the formation system. Activity by professionals asks for novel applications and high performance designs of machines since they are continually needed in evolving/updating systems and engineering tasks. In addition, there is a need to make understandable new methodologies to professionals for practical implementation both of their use and their results. New solutions and innovations are continuously asked not only for technical needs but also for the political/strategic goals of company success. In general, MMS activity is directed for further developments by searching for: • • • • • •

information and understanding of the functionality and impact of systems algorithms for design, operation, and evaluation of systems operation and application for full tasks, as constrained by environmental limits performance evaluation and economic merit of the systems transfer of innovation human-machine interfaces and interactions

Thus, a role of mechanisms in Mechatronics can be understood according to main aspects such as: –– Human-machine interactions –– Mechanical tasks in motion operations –– Structure design for sizing dimensions Therefore, the ‘hot’ topics of Mechanism Design for Mechatronics can be considered to be as follows: • to analyse and to investigate the motion of mechatronic systems and the loads on the component bodies during the operation and performance of a task. • to analyse and to investigate the actions against the environment and within the mechatronic system. • to focus on the safety and security issues both for the system and for its human operators • to consider the Mechanics of interactions • to evaluate situations with mechanical contacts and force transmissions • to size the system actions according to the task requirements • to achieve desired goals and proper working of the overall system • to consider complex motions such as spatial movement at high acceleration • to look at integrated systems via suitable modelling of components of other than a mechanical nature Trends in system composition can be summarized as in the examples in Table 1. Thus, mechanical components will be reduced percentage-wise but nevertheless they will still be necessary and indeed be fundamental for the use and operation of systems.

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Table 1  Examples of evolution of system composition 1960–2000 Mechanics (%) Electronics/informatics (%) Cars 90–50 10–50 Calculators 100–10 0–90 Cameras 100–30 0–70

Fig. 3  An example of mechatronic machine: an autonomous field track

Figure 3 shows an example of a new machine design relating to fully autonomous tracks for agricultural purposes. This involves challenging aspects for MMS since the primary machine task is still focused on the motion through: • Path-planning • Power transmission • Terrain interaction The core of the machine operation still depends on: • the Gear box • the Suspension mechanisms • the Steering mechanisms but with intelligent solutions requiring integration of these mechanical components into a well balanced mechatronic design. The relevance of MMS aspects in such modern mechatronic systems can be summarized as in the scheme of Fig.  4 in which MMS features can be recognized mainly (but not only) in the transmission block for machine motion, but with strong relationships with other components of different natures and goals.

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Fig. 4  A general scheme for a modern machine with mechatronic operation

An important area demanding new system designs may be recognized for service operations that can be understood in terms of sets of actions and behaviours aimed towards achieving a service task. Those service actions and indeed behaviours can be much more articulated and varied than in traditional industrial applications. However in some specific cases, simple operations can be used to obtain the desired service operation. A service task can be understood as the ultimate goal of the design and operation of a service machine, that most of the time is identified as a robot. A service task may be defined with well defined properties or by a large variety of situations. This is, indeed, the main aspect that makes service robots a challenging design problem in practical applications where they need to be efficient and successful for providing a desired service. The above-mentioned considerations can be useful to understand the multidisciplinary integration that is required to design and operate a service robot successfully, in general but also for specific applications. The multidisciplinarity is much wider than in any other engineering field, since, as indicated above, it includes technical aspects, human attitudes (of operators and/or users), human-machine interactions, and environment issues, as already outlined in the scheme of Fig. 1, whose main aim is to stress that all of the above issues are fundamentals for service robots too. Indeed, in developing and operating service robots, other than technical expertise, it is more and more necessary that competence from various other fields of human life and environmental considerations be incorporated. Thus, for example psychologists and biologists (and many others) are welcomed in the R&D teams for designing service robots. Referring to technical aspects, Fig. 5 summarizes the mechatronic character of a service robot, as a traditional robot, but with specific emphasis on those abovementioned peculiarities in terms of interactions with the environment and human beings, and in terms of a careful consideration of the environment. Those interactions should be understood not only in terms of engineering issues (mainly mechanical ones) but by looking at more general aspects, such as for example psychological attitudes and social impacts. A consideration of the environment should also address the problem of how a service robot affects or is affected by it, by analyzing and designing for the variety of conditions and situations. In addition, service robots can be considered efficient and successful when ultimately the cost, both in design and operation, can be properly sized as a function

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Fig. 5  A general flowchart with peculiarities for designing and operating service robots

of the service task and mainly as a function of the affordable budget of users and operators. Thus, indeed, economic evaluation and management will be included both in the R&D and in the design of service robots, even from the outset with a strong influence on technical issues. Once the service robot problem is properly outlined, by using the above considerations and maybe even with specific further observations, the challenges can be understood both, in general and specifically, for given applications and service tasks. In particular, the challenges for service systems can be understood to reside in: –– operating together with (or for) human users, with suitable behaviours and careful user-friendly operation; –– operating service tasks with proper easy-operation modes at user-oriented cost. Even more challenging can be the problem of how to make acceptable both from a psychological and a technical viewpoint a service system for a novel application in a frame in which users traditionally do not work or use technical means. Thus, major challenges are faced in the design of systems that have to be acceptable to new users. This may require an adjustment to include specific features of the novel applications, even if they may be thought not essential or functional for the design

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and operation of the new service system. It is also challenging to convince operators and users from those novel application areas to cooperate in developing solutions or even in identifying main problems for design and operation of a new service system. Often serious difficulties arise caused by cultural barriers that make it difficult for designers and users to understand each other. Particularly challenging is how to identify specific issues in proper engineering models which can be understood by the new operators and users, especially when the latter are not from technical fields. All the above considerations can be considered as attaining also to the process and transfer of innovation, which will be understood not only as a technical advance but more widely as an enhancement of the quality of life in all its aspects with the help and support of technical means. Ultimately, construction and validation of the prototype can be considered challenges both for engineers and for new operators/users when not only the efficiency is considered but also user acceptance and education towards a proper awareness of the use of a service system. Fig 5 summarizes these viewpoints by outlining a general approach for designing service systems with the aspects and challenges mentioned above. In particular, the main flow of design activity is indicated in the central streamline as referring to data identification in both technical and non-technical aspects, consideration of technical constraints/issues, analysis of service operation and goal, design activity and system programming, with final checks by operators and users. The care on technical design activity is indicated as system design and operation planning since much of this is strongly influenced by aspects and activities that are grouped in the two lateral blocks as concerned with interactions with human beings and the environment, respectively. Each indicated item refers to aspects that even with nontechnical concerns must be included in the development of proper models and problem formulation as synthetically indicated in the box for task features and constraints. The list of topics is not exhaustive, but is aimed at outlining the many different aspects that should be considered as guidelines. The arrow towards the block for task features and constraints can be understood as referring to activity for modelling an engineering formulation of those issues and their corresponding problems in service systems. In the left block in Fig. 5 several items have been grouped because of lack of space and a major emphasis has been given to user-oriented functionality and user education in dealing with personnel and their attitudes for machine use, as well as to safety issues and environment care in dealing with the more technical aspects of interactions that are listed in the right block. Perhaps the proposed flowchart has simplified the cross-over effects of each aspect on specific but overall peculiarities for designing and operating a service system, but the scheme can be useful in providing a general overview of multidisciplinarity in service system with aspects of very different natures. Special emphasis has been indicated relating to the acceptance by operators and users that will require reiteration of consideration of all the aspects and the design process itself. Renewed interest is also addressed to experimental activity both for validation and calibration purposes.

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Experimental activity can be aimed at checking system features, at evaluating operation performance, and at characterising application goals. Thus, it can be considered fundamental from the first stages of design activity in order to properly identify design parameters and task characteristics. In addition, it is also instrumental in confirming a practical feasibility of a design, with proper parameter experimental identifications and behaviour calibrations. In Fig. 6 general considerations a

b

Fig. 6  Schemes for experimental activity: (a) a general strategy; (b) test outputs

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are outlined by addressing the main aspects for an experimental activity with an eye to the mechanics of the mechanism operation that is the part of a mechatronic multi-body system performing a mechanical task and/or interacting with the environment and human users. Thus, in the experimental strategy in Fig. 6a each block represents an area of specific activity, and although the activities may be carried out sequentially as indicated, each one may require specific attention even in recursive procedures and implementations. It is to be noted that even an experimental activity will require multidisciplinary expertise as referring to measurements technology and technique, but also to system operation and performance analysis. It is also remarkable that in general successful experimental activity needs recursive/iterative adjustments of the experimental layout both in term of prototype features under test and sensor implementation. In addition experimental results need to be treated with statistical analysis, which require the repetition of tests in a robust procedure. Another of the main aims of an experimental activity can be recognized in the possibility to discover or to confirm parameter functionalities that are fundamental for the system. A sensitivity analysis and a check of secondary effects are also significant for a proper experimental evaluation of the test outputs. In Fig.  6b a general scheme is outlined to stress, without any intention of being exhaustive, the areas and parameters that can be used for a mechanics characterization both of the lab test and of the system behaviour. Of course, each of the reported blocks and considerations needs careful attention in designing and performing the experimental activity, even during the run of tests yet. Summarizing, since system designs are in general aimed at tasks and operations with mechanical aspects, owing to mechanisms and end-effector components (since they interact or serve with human operators in mechanical environments), experimental activity with mechanics results can be very important for the market success and user acceptance of new and old systems.

Activity and Role of IFToMM As historically introduced above, IFToMM is an international federation whose mission is the promotion of MMS through facilitating worldwide dissemination, collaboration and advances in all the fields of MMS. IFToMM’s composition relating to activities for its mission is summarized in the diagram of Fig. 7. The main bodies of IFToMM are the General Assembly (GA), the Executive Council (EC), the Permanent Commissions (PCs), and the Technical Committees (TCs). The General Assembly (GA) is the supreme body of the Federation and determines its policy. It is composed of the Chief Delegates of IFToMM Member Organizations and members of the Executive Council. It is the body that decides and outlines the activity and strategies of IFToMM through general guidelines.

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Fig. 7  IFToMM bodies and activities

Usually the GA meeting is held every 4 years during the IFToMM World Congress. The current GA is composed of the following 47 MOs: ARMENIA, AUSTRALIA, AUSTRIA, AZERBAIJAN, BELARUS, BRAZIL, BULGARIA, CANADA, CHINA-BEIJING, CHINA-TAIPEI, CROATIA, CZECH REPUBLIC, DENMARK, EGYPT, FINLAND, FRANCE, GEORGIA, GERMANY, GREECE, HUNGARY, INDIA, ISRAEL, ITALY, JAPAN, KAZAKHSTAN, KOREA, LITHUANIA, MACEDONIA, MEXICO, MONGOLIA, NETHERLANDS, PERU, POLAND, PORTUGAL, ROMANIA, RUSSIA, SERBIA, SINGAPORE, SLOVAKIA, SLOVENIA, SPAIN, SWITZERLAND, TUNISIA, UKRAINE, UNITED KINGDOM, USA, and VIETNAM. The Executive Council manages the affairs of the Federation between the sessions of the General Assembly. It is elected every 4 years, meets annually, and is composed of the President, Past President, Vice-President, Secretary-General, Treasurer, and six ordinary members. The President has the role of Chair. The main task of the EC is to guide the activity of IFToMM as decided by the GA and to perform the necessary actions during the 4-year term. The current EC is composed by Prof. Marco Ceccarelli (President), Prof. Kenneth Waldron (Past President), Prof. Yoshihiko Nakamura (Vice President), Prof. Carlos Santiago López-Cajún (Secretary-General), Dr Joseph Rooney (Treasurer), and members: Prof. Datong Qin, Prof. Veniamin I. Goldfarb, Prof. Theodor Ionescu, Prof. Barham Ravani, Prof James Trevelyan, Prof. Miroslav Václavík, Fig. 8. The PCs and TCs are the technical bodies in which the activities of IFToMM are carried out in their main aspects for teaching and research advances. Each Permanent Commission and Technical Committee is composed of a Chairperson,

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Fig. 8  EC Members, chair of TC for transportation machinery, and the Mexican delegation with Prof. Chicurel, host of the 42nd IFToMM EC meeting in 2009 in Guanajuato, Mexico

appointed by the Executive Council, together with a Secretary and members, nominated by the Chairperson and appointed by the Executive Council. A Chairperson shall not serve for more than two terms consecutively. The general goals for the work of the Commissions and Committees are aimed at promoting their fields of interest by attracting researchers and practitioners, and especially including young individuals, in order to: –– –– –– –– ––

define new directions in research and development within their technical areas; establish contacts between researchers and engineers; initiate and develop bases and procedures for modern problems; promote the exchange of information; organize national and international symposia, conferences, summer schools, editorial works, and meetings. Currently the following PCs are established as in the IFToMM Constitution:

Communications (Chair: Prof. Leila Notash) Education (Chair: Prof. Juan C. García-Prada) History of MMS (Chair: Prof. Hanfried Kerle) Publications (Chair: Prof. Edward Walicki) Standardization of Terminology (Chair: Prof. Antonius J Klein-Breteler) Current TCs working in specific scientific hot topics are: Computational Kinematics (Chair: Prof. Doina Pisla) Gearing and Transmissions (Chair: Prof. Daizhong Su) Human-Machine Systems (Chair: Prof. Karol Miller) Linkages and Cams (Chair: Prof. Burkhard Corves) Micromachines (Chair: Prof. G.K. Ananthasures) Multibody Dynamics (Chair: Prof. Javier Cuadrado) Vibrations (Chair: Prof. Marian Wiercigroch) Reliability (Chair: Prof. Irina V. Demiyanushko) Robotics and Mechatronics (Chair: Prof. I-Ming Chen)

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Rotordynamics (Chair: Prof. Rainer Nordmann) Sustainable Energy Systems (Chair: Prof. Ion Visa) Transportation Machinery (Chair: Dr. Madhu Raghavan) Tribology (Chair: Prof. Jianbin Luo) Conferences are organized directly by PCs and TCs often in collaboration with other communities, with the aim to have international forums in which to disseminate and exchange research and professional experiences and advances. Today a large number of conferences show IFToMM patronage but many others, mainly at national and local levels, are not explicitly linked to IFToMM, although they are still mainly within the IFToMM community. A similar situation occurs for editorial works and international collaborations that are continuously being proposed/established thanks to IFToMM but that are not clearly expressed under the umbrella of IFToMM. This has motivated a Presidency plan during the term 2008–2011 for achieving a better visibility of IFToMM activities, as stressed in many messages by the current president. This better visibility can give not only proper credit to IFToMM for each activity, but can also stimulate a more widespread consciousness of the considerable influence of IFToMM in the worldwide activity in MMS with more support from funding entities (see open letter by Ceccarelli and Waldron [34]). The role of the IFToMM community can be more influential when its activities are well recognized and appreciated not only at international level (as it is already), but also in national and local frames. An important conference event for the IFToMM community is the IFToMM World Congress that is celebrated every 4 years. At the previous one in Besançon, France in 2007 there were more than 700 delegates from all the IFToMM MOs as well as from other countries, thus demonstrating the growth of IFToMM and its role worldwide. Next one will be heldi in Guanujato, Mexico on June 2011. IFToMM’s activities and its goals are emphasised synthetically in the outputs that are outlined in Fig. 7 as R&D, Innovation and professionals. The activities of IFToMM can be better understood mainly from two viewpoints, namely political and executive. From the political viewpoint, IFToMM’s role can be understood as being leadership in guiding organization and strategic activities with international coordination in order to make common frames for further developments in the world community. From the executive viewpoint, IFToMM carries out activities in organizing and coordinating several initiatives, such as conference events, meetings, and editorial works via the bodies of the member organizations (MOs) but specifically through permanent commissions (PCs) and technical committees (TCs). These initiatives are indicated with IFToMM format and patronage mainly at the international level, but the IFToMM community programs these initiatives also within national and local frames as still relevant in quality and quantity. The results of these initiatives are disseminated worldwide, even in areas that are not yet linked to IFToMM. Thus, IFToMM activities are only partially visible under the explicit IFToMM umbrella, as reported in the IFToMM webpage. Those initiatives can be considered as directly influential in the academic world, but they are related to and are effective also within professional environments

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because of the consequence of formational activities and applied research with innovation transfer. However, besides IFToMM being an international institution, its role and success depend on the activities of individuals, who are enrolled in the IFToMM bodies and thereby entitled to IFToMM benefits and by those who are within the MMS community at large. Thus, the role of IFToMM may be recognized as one showing leadership and guidance to the worldwide community working in MMS with the aim to facilitate common visions for future developments but also to stimulate collaboration and organization of activities at international level. With this role, IFToMM may be understood as a reference institution both in giving identity to the international community working in MMS and in proposing direction for worldwide activity in MMS developments.

Conclusions Not everything is new or recently developed in MMS, although innovation seems to be a priority today. But this does not mean that there is no interest in, nor that there is no need to work on developing and enhancing knowledge and application of MMS. New challenges are determined for MMS in the new needs of Technology and Society both in terms of developing new solutions and of updating past systems. An awareness of the historical background can give not only a conscious understanding of past efforts and solutions, including their paternity, but even more importantly it can help to find/develop ideas for new and updated problems to be solved. But the rapidly evolving needs of Technology and Society will require a continuous re-thinking and re-conceiving of methodologies and solutions in suitable updated applications. Thus, the main challenges for future success in MMS may be recognized in the community’s capability of keeping abreast of developments in the field and therefore in being ready to solve new and updated problems with new ideas or by refreshing past solutions, as has been done successfully in the past. IFToMM plays an important role in this contest since it is an international institution of worldwide reference with the aim to lead and facilitate international collaboration in guiding future developments. Acknowledgements  The author wishes to thank Prof. Adalberto Vinciguerra from ‘La Sapienza’ University of Rome, who with his mentoring guide has transmitted his interest and enthusiasm for international collaboration and particularly for IFToMM. Among many other IFToMM officers, the author is also very grateful to the past IFToMM Presidents Prof. Bernard Roth, late Prof. Adam Morecki, and Prof. Jorge Angeles, who with their advice and encouragement helped him to reach a maturity both in engineering science and in IFToMM business. Finally the author wishes to thank Prof. Carlos Lopez-Cajùn, current IFToMM Secretary General, and Dr. Joseph Rooney, current Treasurer, for their friendship and strong support with discussions and advice during these years of IFToMM Presidency. Dr. Rooney is also acknowledged for revision and comment of this paper.

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References* 1. Chasles, M.: Apercu historique sur l’origin et le développement des méthodes en géométrie. Mémoires couronnés par l’Académie de Bruxelles, vol.11 (2nd ed. Paris, 1875) (1837) 2. Chasles, M.: Exposé historique concernant le cours de machines dans l’enseignement de l’Ecole Polytechinique. Gauthier-Villars, Paris (1886) 3. Crossley, E.F.R.: Recollections from forty years of teaching mechanisms. ASME J. Mech. Trans. Autom. Des. 110, 232–242 (1988) 4. De Groot, J.: Bibliography on Kinematics. Eindhoven University, Eindhoven (1970) 5. De Jonge, A.E.R.: A brief account of modern kinematics. Trans. ASME 663–683 (1943) 6. Dimarogonas, A.D.: The origins of the theory of machines and mechanisms. In: Erdman, A.G. (ed.) Modern Kinematics – Developments in the Last Forty Years, pp. 3–18. Wiley, New York (1993) 7. Ferguson, E.S. Kinematics of mechanisms from the time of Watt. In: Contributions from the Museum of History and Technology, Washington, paper 27, pp. 186–230 (1962) 8. Hartenberg, R.S., Denavit J.: Men and machines an informal history, Machine Design, May 3, 1956, pp. 75–82; June 14, 1956, pp. 101–109; July12, 1956, pp. 84–93 (1956) 9. Koetsier, T.: Mechanism and machine science: its history and its identity. In: Proceedings of HMM2000 – the First IFToMM International Symposium on History of Machines and Mechanisms, pp. 5–24. Springer, Dordrecht (2000) 10. Nolle, H.: Linkage coupler curve synthesis: a historical review –I and II, IFToMM. J. Mech. Mach. Theor. 9(2), 147–168 (1974); pp. 325–348 11. Reuleaux, F.: Theoretische Kinematic, Chapter 1. Fridrich Vieweg, Braunschweig (1875) 12. Roth, B.: The search for the fundamental principles of mechanism design. In: International Symposium on History of Machines and Mechanisms – Proceedings of HMM2000, pp. 187–195. Kluwer, Dordrecht (2000) 13. Ceccarelli, M. (ed.): International Symposium on History of Machines and Mechanisms – Proceedings of HMM2000. Kluwer, Dordrecht (2000) 14. Ceccarelli, M. (ed.): International Symposium on History of Machines and Mechanisms – Proceedings of HMM2004. Kluwer, Dordrecht (2004) 15. Yan, H.S., Ceccarelli M. (eds.): International Symposium on History of Machines and Mechanisms – Proceedings of HMM2008. Springer, Dordrecht (2008) 16. Ceccarelli, M.: From TMM to MMS: a vision of IFToMM. Bull. IFToMM Newsl. 10(1) http://www.iftomm.org (2001) 17. Ceccarelli, M.: The challenges for machine and mechanism design at the beginning of the third millennium as viewed from the past. In: Invited Lectures, Proceedings of Brazilian Congress on Mechanical Engineering COBEM2001, Uberlandia, pp.132–151, vol. 20 (2001) 18. Ceccarelli, M.: Classifications of mechanisms over time. In: Proceedings of International Symposium on History of Machines and Mechanisms HMM2004, pp. 285–302. Kluwer, Dordrecht (2004) 19. Ceccarelli, M.: Challenges for mechanism design. In: Keynote paper, the 10th IFToMM International Symposium on Science of Mechanisms and Machines SYROM’09, Brasov, pp.1–13. Springer, Dordrecht, 12–15-Oct 2009, ISBN 978-90-481-3521-9. DOI 10.1007/97890-481-3522-6 20. Ceccarelli, M.: Early TMM in Le Mecaniche by Galileo Galilei in 1593. Mech. Mach. Theor. 41(12), 1401–1406 (2006) 21. Crossley, F.R.E.: The international federation for the theory of machines and mechanisms. J. Mech. 5, 133–145 (1970) 22. IFToMM.: IFToMM Commission A. Standard for terminology. Mech. Mach. Theor. 26(5) (1991)

* The reference list is restricted for limitations of space to main works for further reading and to the author’s main experiences.

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23. IFToMM: Standardization and terminology. Mech. Mach. Theor. 38(7–10), special issue (2003) 24. Lanz, J.M.: Betancourt, A.: Essai sur la composition des machines, Paris (1808) 25. Masi, F.: Teoria dei meccanismi. Zanichelli, Bologna (1897) 26. Uicker, J.J., Pennock, G.R., Shigley, J.E.: Theory of Machines and Mechanisms. Oxford University Press, New York (2003) 27. Ceccarelli, M.: On the meaning of TMM over time. Bull. IFToMM Newsl. 8(1) http://www. iftomm.org (1999) 28. Angeles, J., Bianchi, G., Bessonov, A.P., Maunder, L., Morecki, A., Roth, B.: A history of IFToMM, Chapter 2. In: Proceedings of HMM2004 – the Second IFToMM International Symposium on History of Machines and Mechanisms, pp. 25–125. Springer, Dordrecht (2004) 29. Ceccarelli, M.: IFToMM celebration for 40th year celebration. Mech. Mach. Theor. 45, 119–127 (2010) 30. Crossley, F.R.E.: The early days of IFToMM. In: Proceedings of 8th IFToMM World Congressm, Prague, pp. 4–9, vol. 1 (1991) 31. Maunder, L.: The progress of IFToMM. Mech. Mach. Theor. 15, 415–417 (1980) 32. Maunder, L.: Report: the scientific activity of IFToMM. Mech. Mach. Theor. 23, 329–332 (1988) 33. Morecki, A: International friendly thinkers organization (who likes) machines and mechanisms (IFToMM) – where are we going? In: Proceedings of 10th IFToMM World Congress, Oulu (1999) 34. Ceccarelli, M., Waldron, K.J.: Open letter from IFToMM. IFToMM webpage (2009) 35. Ceccarelli, M.: Preliminary studies to screw theory in XVIIth century, Ball Conference, Cambridge, CD Proceedings (2000) 36. Ceccarelli, M.: A historical perspective of robotics toward the future. Fuji Int. J. Robot. Mechatron. 13(3), 299–313 (2001) 37. Ceccarelli, M.: IFToMM activity and its visibility. Bull. IFToMM Newsl. 13(1) http://www. iftomm.org (2004) 38. Ceccarelli, M.: Evolution of TMM (Theory of Machines and Mechanisms) to MMS (Machine and Mechanism Science): an illustration survey. Keynote Lecture, 11th IFToMM World Congress in Mechanism and Machine Science, Tianjin, vol.1, pp.13–24 (2004) 39. Ceccarelli, M.: Renaissance of machines in Italy: from Brunelleschi to Galilei through Francesco di Giorgio and Leonardo. Mech. Mach. Theor. 43, 1530–1542 (2008) 40. Ceccarelli, M.: A short introduction on IFToMM officers over time. In: Proceedings of HMM2008- the Third IFToMM International Symposium on History of Machines and Mechanisms, pp. 3–10. Springer, Dordrecht (2008) 41. Bottema, O., Freudenstein, F.: Kinematics and the Theory of Mechanisms, Appl. Mech. Rev. 19(4), 287–293 (1966) 42. Morecki, A.: Past present and future of IFToMM. Mech. Mach. Theor. 30, 1–9 (1995) 43. Shah, J.J. (ed.): Research Opportunities in Engineering Design – Final Report to NSF, NSF Strategic Planning Workshop. ASME DETC, Irvine (1996) 44. Roth, B.:” Robots – state of art in regard to mechanisms theory”. ASME J. Mech. Transm. Automat. Des. 105, 11–12 (1983)

Promoting Novel Approaches of MMS for Sustainable Energy Applications Ion Visa

Abstract  Sustainable product design and development has gone global by involving teams from all over the world, developing new/innovative, high-tech products, aiming to implement sustainability in our knowledge-based society. RT&D and education in product design must comply with these requirements. Mechanical Systems (MS), as product components must also comply, thus general methods for MS modelling and design are compulsory. The paper discusses the involvement of MMS in promoting sustainable energy systems; mechanical and mechatronic systems in renewables are presented along with energy efficient applications in automotives. A proposal to establish a new IFToMM Technical Committee for Sustainable Energy systems is also presented and justified.

Introduction Energy represents one of the most powerful tools for our present and future development and one of the major problems of humankind. Energy promotes global industrial development and personal comfort but, the present pattern for energy production, use and end-of-life disposal is responsible for a large share of environmental pollution and for worldwide (in)security – to mention just two of the humankind problems. Today, our common energy sources are fossil and nuclear fuels, raising significant problems due to their limited amount and the wastes that result during energy production; today’s energy consumers, both in residential and industrial applications, are wasting plenty of energy in non- or average efficient processes, equipment or buildings. Therefore, sustainable solutions for the future must be related to three aspects: (1) new energy sources, clean, and if possible inexhaustible - renewable energy sources; (2) energy efficient processes and (3) energy

I. Visa (*) Transilvania University of Brasov, Eroilor Bd., 29, Brasov 500036, Romania e-mail: [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_2, © Springer Science+Business Media B.V. 2011

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saving applications. Sustainable Energy represents the concept joining these three conceptual lines, developed in the 1990s, as an answer to the need for a concrete path of sustainable development. Seven major areas were identified as relevant to sustainable energy development, including: energy resources and development; efficiency assessment; clean air technologies; information technologies; new and renewable energy resources; environment capacity; mitigation of nuclear power threat to the environment, [1]. Implementing a sustainable energy concept and requirements needs an inter- and trans-disciplinary approach and engineering plays a key role. It is not only energy and electrical engineering that must be involved, but there are strong and concrete issues that need to be solved by mechanical, mechatronic, materials and civil engineering, along with IT or robotics. And, to unify the emerging concepts in new, optimized and efficient products there is needed a new product design concept, the Integrated Sustainable Product Design. Changing energy production and use models must be done by providing affordable, marketable solutions, accepted by both industrial companies and by end-users, therefore the already existing experience in product design and development represents an asset. The science of machines and mechanisms plays a key role in this quest for sustainability.

Sustainable Energy and MMS Large-scale hydropower and biomass combustion systems are dominating the search for renewable energy production. In addition to these systems, wind turbines, photovoltaic and solar thermal systems have grown rapidly in the past decade and together are expected to be 20% of total energy production in the EU, by 2020. The MMS contribution to reaching this target is substantial and is related to key mechanisms in the systems’ functioning (as for wind turbines and hydropower station) or to advanced solutions for increasing the conversion efficiency, as these are the tracking mechanisms for PV and PV-concentrator systems and for solar-thermal collectors, either flat or concentrating. Plenty of studies have been devoted during the past 5 years to solar energy conversion, especially for photovoltaic convertors, because of a complex of concurrent factors: (1) while wind, hydropower or tides are unevenly distributed, solar energy is quite equally available, thus representing a path for global (energy) security; (2) the state of the art of photovoltaics, based on silicon, have a limited conversion efficiency, due to the material’s physics (up to about 32%), thus research focuses on increasing the amount of solar radiation on the PV module, by using tracking systems and/or radiation concentrators. The tracking systems can be mono- or bi-axial, according to the accuracy targeted in following the sun’s path. In choosing a tracking solution, besides this accuracy, other factors must also be considered: the energy gain versus the energy consumed during tracking, the construction limitations, the price. Solar thermal collectors are usually equipped with mono-axial systems, both for flat and for concentrating collectors. The PV trackers are usually bi-axial

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Fig. 1  Trackers: (a) equatorial; (b) pseudo-equatorial; (c) azimuthal

Fig. 2  PV tracked platform installed in the Transilvania University of Brasov

providing a daily motion and a seasonal motion. According to their order, the bi-axial trackers can be equatorial, pseudo-equatorial or azimuthal, Fig. 1. Tracking can be insured by linkages mechanisms, [2–5], gear mechanisms, camfollower mechanisms, [6, 7], by hydraulic systems – especially for big loads in large PV platforms. One example is the tracking system developed by the Transilvania University of Brasov, [8, 9], in the project PV Twin Laboratory, consisting of a tracked PV platform with bi-axial, pseudo-equatorial tracking system having an actuator and a hydraulic motor, Fig. 2. The platform acts as an out-door testing stand for four different types of PV modules and functions beginning in 2008. Many renewable energy systems require transmissions to modify the input speed. The solar systems drive trains include a speed reducer, while the wind turbines

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and hydro units usually contain a gearbox to increase the speed of the input shaft to the generator. Hydropower convertors represent thus another application field for MMS; large plants, of thousands of MW are developed but the main unexploited potential lies in small rivers; developing small hydros (with installed power lower than 5 MW), using the potential of variable water sources, with minimal/null investment in dams or water storage systems (run-of-river design) represents the target of many studies and requires novel solutions for efficient mechanical transmissions and for rotor blade design, aiming for efficient running of the turbine all through the year, [10]. Wind turbines registered the most dynamic development in the past 5  years, mainly because their development gives maximal use of the existent experience in mechanical, mechatronic and electric systems, [11]. Due to the large wind turbine development (up to 5 MW), electricity cost is comparable to the production costs of power based on fossil fuels, and – in the other limit of magnitude – small or micro-wind turbines were developed, starting at very low wind speed (10 times the rated torque in the drive train that resulted in the drive train bearing failure. This bearing failure triggered tripping of the machine and also altered the critical speeds giving rise to two new critical speeds. The rotor coasted down and passed through these two critical speeds, through the first one without much difficulty as the rotor nodal point was at the fifth stage blade location; whereas when it came to the second critical speed it hovered and rubbed with the casing for a fairly long period of a few milliseconds. At this speed there was an antinodal point at the fifth stage which triggered heavy rubs. These heavy rubs created blade tip loads due to friction and normal loads coming from the rotating blades that led to blade failure in the local plastic regions of the dovetail. At that time the machine blew up completely and the sudden rotor stop caused the earthquake-like signal with the loads transmitted through the ground alluvial soil to the recoding station. Those few milliseconds of rotor hovered at 18  Hz before the final failure of blades gave important clues and technology development in fracture mechanics and lifing. Crack initiation and propagation threshold conditions, and crack growth calculations until unstable conditions, matched so well that they clinched the failure scenario. The crack growth during the bench mark period and during the multiple crack periods of a few milliseconds due to rub measurements under an Electron Microscope is shown in Fig. 8. The match was excellent in striation spacing as well as time for travel before failure. The above exercise was all done with expertise developed internally in India with flow, structural dynamics, rotor dynamics, lifing technologies for globally elastic and locally plastic structures and fracture mechanics. This investigation led to the development of Continuous On-Line Condition Monitoring systems, On-Line Diagnostics for Nuclear Power Plants in India. The data acquisition systems and the

Fig. 8  Crack growth during normal and during rubbing conditions

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hardware was internally developed at The Bhabha Atomic Research Center and the software completely developed, tested and installed – this system monitors the TG sets continuously and are still operating in the stations. This kind of system is perhaps the first of its kind in the world. The practice of structural dynamics moved away from writing codes to adoption of commercial and rugged solvers to handle large size finite element models, thus allowing precise estimation of alternating stresses at stress raiser level locations. This allowed a precise life estimation by estimating true stress and strain conditions and a strain-based life estimation.

Twenty-First Century The end of the twentieth century saw significant changes; the most visible was the emergence of private global R&D agencies making important contributions to the development of India. Several opportunities came to the doorsteps from Indian Defense, Space and Nuclear departments besides several multinational automotive and aerospace industries. We will discuss in a brief manner these developments in Turbomachinery. In tune with the trend of reduction of design and testing time, India made an important breakthrough in analytically determining hysteresis and friction damping through a user-friendly commercial application using a HyperWorks platform in line with experimentally defined nonlinear damping models. Simultaneously, commercial CFD codes are used to evaluate pressure distribution due to flow interference, e.g., in Cryogenic Liquid Propulsion engine turbines. Precise methods with nonlinear damping models were established to determine the resonant stresses while crossing critical speeds, thus enabling life estimation as a truly simulating venture and decreasing the design cycle time as well as helping in trouble shooting. For example, the lifetime for crack initiation of Bhakra Nangal blade cracks was estimated and shown to be close to the practically observed results. Indian technologists quickly established methods of lifing of globally elastic but locally plastic structures using Neuberization and estimating true strains in the regions where strain concentration takes place. These methods were used in lifing of aircraft engines. In fact Engineers in private industry came up with designs for military aircraft engines. In Kaveri engine designs, CFD processes were successfully used to determine Heat Transfer Coefficients, Bulk temperatures in thermo-mechanical design for expansions and rubbing prevention. Conjugate heat transfer calculations when necessary were employed for thermal management of the engine. Complete stress calculations were performed under centrifugal loads, gas loads, and thermal loads to determine the mean stresses of the engine rotor and bladeddisk system. Likewise the stationary part of the engine, the supports, front and middle frames, and casing were analyzed. The Indian engineers in industry developed technologies to handle the bolted joints between the disks and seal drums and

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Fig. 9  Twin spool aircraft engine rotor dynamics

design them optimally for durability and safety. Another specialty is development of methods to determine the stiffness of the engine at support locations for the purpose of rotor dynamics design. The solid model Rotordynamics came to perfection with the ability of coupling two solid rotors with mounted blades and flexible supports and casing and determining unbalance response. The bearing stiffnesses and damping characteristics of rolling element bearings are used to couple the rotors amongst themselves and with the casing. India is the first country to develop this capability. The unbalance response of the twin spool rotors with the casing is shown here in Fig. 9. Solid model rotor technologies are also used for misaligned shafts, shafts with asymmetry; transient analysis was developed to study the instabilities in the system. The results are verified from the literature with beam models. Technologies and software were also developed for remote condition monitoring and diagnostics and demonstrated in Cairns, Australia with a running rotor in Bangalore. With the cryogenic engine development for the fourth stage launching in Geostationary Launch Vehicle into further development (this engine is expected to be deployed in the next launch), the rotor dynamics reached another peak in the analysis. The solid model analysis for the turbine, Hydrogen Pump and Oxygen Inducer with seals between each chambers, several bearings and casing are all modeled together. Campbell diagrams were developed to determine the critical speeds from linear analysis. The response predicted did not match with tests in ISRO; then nonlinearities in the bearings were accounted by a transient analysis to pick up the speeds at which peak amplitudes occur. The rolling element bearings had significant nonlinearity that has changed the performance of rotor under unbalance. The peak amplitudes also decreased because of nonlinearity. The rotor acceleration had significant influence in carrying it through a critical period without building resonance and limiting the response. The unbalance response of the engine is shown in Fig. 10. A significant outcome of this analysis was to show spin softening effect on the backward whirl frequency which falls rapidly and disappears beyond the critical speed, unlike the so-called gyroscopic effect from a one-dimensional model.

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Fig. 10  Solid model unbalance response of a liquid propulsion engine

India has also developed solid rotor models to couple with the foundation in the analysis of TG sets affected by the foundation. The influence of test beds of aircraft engines is shown to be of importance in Hindustan Aeronautics Ltd., amongst others in understanding why the test results vary from the predicted response. This century has seen modern light weight designs; Optimization has become a commercially viable tool for topology and shape of stationary structures; e.g., OptiStruct was used to take away 500 kg from Airbus 380 wings. This technology was developed for rotating machines, aircraft engine supports and frames, blades … Morphing technology was utilized to the most advantage by the designer in saving meshing and computational time of bladed-disk structures to minimize the local strains at singularities and increase life substantially for globally elastic and locally plastic dovetail conditions. This technology is a true simulation that can bring down expensive spin rig tests. For multiphysics problems, and nonlinear analysis, HyperStudy is used in shape and weight optimization, for example in high-speed bladed-disks. Research is under way for reducing computational efforts in choosing the DOE metamodels. Shape optimization and weight optimization results are shown in Figs. 11 and 12. The analytical determination of equivalent viscous damping as a function of strain amplitude in a given mode of vibration at a given critical speed is embedded as a process manager to enable the designer to implement simulation rather than carry out tests. The experience gained and technologies developed in life are quickly utilized to develop a user-friendly commercial tool TurboManager to determine life using stress based and strain based methods, fracture mechanics and minimize the same. This tool is also expected to take away the drudgery from a skilled engineering pool and reduce the design cycle time and also help in diagnostics.

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Fig. 11  Optimized blade root that increased life by four times

Fig. 12  Optimized blade for weight reduction

TurboManager along with OptiStruct is used in redesigning rotor blades with composite materials for a light combat helicopter. The condition monitoring and diagnostics system designed and developed for nuclear machines is recently made into a general purpose tool operating on a HyperWorks platform where the digital data acquired is recorded, retrieved, processed and analyzed in frequency and time domains, orbital domain and trend plotting in TurboManager; HiQube is used to manage the data from all bearings. User specific diagnostics can be used to supplement this system. This can be a general on-line condition monitoring system that can be called from TurboManager and combined with Rotordynamics codes to operate as future prognostics tools.

Concluding Remarks IFToMM played a key role in bringing scientists together onto a common platform and spread the literature amongst all countries. Besides the world conferences once every 4 years, IFToMM has organized several technical committees and commissions

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to plan several activities and provide a meeting place for eminent scientists and young researchers to easily understand the trends; one such early committee was Rotor Dynamics. This committee has immediately taken the task of bringing top rotor dynamics researchers together in world conferences and became one of the leading three such groups in the world. These activities are well coordinated with The Institution of Mechanical Engineers in London and American Society of Mechanical Engineers International Gas Turbine Research India. There is excellent cooperation between them, so much so that there is a major event every year around the world. India has taken to full advantage these sets of conferences through which the developments across the world are tracked and research work planned as needed by the country. This paper has outlined the outcome of such research activity in educational and research institutions, public and private industries during the last 4–5 decades. Acknowledgements  The author has been one of the beneficiaries in India to receive considerable support from the Government of India, Defence Ministry, Indian Space Organization, Bhabha Atomic Research Center, several of his friends, students and colleagues from India and abroad; particularly from Altair Engineering Inc., he is deeply indebted to them.

A Brief History of Legged Robotics P.J. Csonka and K.J. Waldron

Abstract  Research in the area of legged robotic systems has spanned almost the entire history of modern robotics. IFToMM has played a crucial role in this history by providing a channel of communication between East and West during the cold war period, and via its Technical Committee on Robotics in more recent years. In this chapter we have attempted an overview of what has become a vigorous field of research.

Introduction Legged robots appeared very early in the modern history of robotics. The first walking robot in the modern sense: a mechanical system coordinated by a computer, was the Phony Pony [1] which first walked in 1968. It was a simple, fourlegged machine shown on Fig. 1, with two degrees of freedom per leg that allowed it to walk in a straight line only. Leg phasing was programmed in the computer as a simple state machine. McGhee and Frank also published the first mathematical description of the leg phasing problem, namely a mathematical definition of a quadrupedal wave gait [2]. IFToMM played a crucial part in this development, primarily through its cosponsorship of the ROMANSY symposia with CISM. These symposia became a primary locus of presentation for the small community engaged in research in legged locomotion. As evidence for this, the very first ROMANSY symposium held in Udine in 1973 boasted no fewer than 11 papers on legged locomotion out of a P.J. Csonka and K.J. Waldron (*) Robotic Locomotion Laboratory, Stanford University, Stanford, CA, USA e-mail: [email protected] K.J. Waldron  Department of Mechanical Engineering, Terman Engineering 521, Stanford University, Stanford, CA, 94305-4021, USA e-mail: [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_5, © Springer Science+Business Media B.V. 2011

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Fig. 1  The phony pony (1986)

total of 45. One reason for this was that there were leading research teams in both the U.S.A. and U.S.S.R. working during the seventies and eighties and ROMANSY was one of a very few meetings that researchers from both groups could aspire to attend. Consequently, ground-breaking results were often first presented in this forum. The famous simulation film clip sometimes referred to as “A Soviet Ant Takes a Walk” was literally smuggled out of the U.S.S.R. under one of the researcher’s coat so it could be shown at an early ROMANSY conference. Later, when it became less difficult for researchers to meet face-to-face ROMANSY continued to be an important forum for work on legged robotic systems. Until 1990, the ROMANSY Organizing Committee also functioned as the IFToMM Technical Committee on Robots and Manipulators. At that time it was decided to establish the Technical Committee as a separate entity. The second author of this chapter was its first chair. Through the technical committee, IFToMM has continued to sponsor activities in robotics including ROMANSY, ARK (Advances in Robot Kinematics) sessions in the World Congress and other meetings. There had been quite a number of earlier legged locomotion machines including an ancient Chinese walking cow and various mechanical automata. Space General Co. built a purely mechanical machine in which the eight legs were cycled by cam mechanisms, which demonstrated impressive mobility in natural terrain [3]. In the same time-frame the General Electric Quadruped was constructed (Fig. 2).

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Fig. 2  GE quadruped (1968)

This was a large four-legged machine that carried a human operator who directly controlled the leg movements by means of a harness [4]. All joints were actuated by bilateral force-reflecting hydraulic systems that translated the movements of the operator’s legs and arms into movements of the machine, while reflecting the scaled down loads on the machine joints to the operator’s harness. There was no computer coordination used on any of these machines, so they were not robots in the modern sense. McGhee and his students built the OSU hexapod, a simple, six-legged walking machine. Its splayed legs made the machine resemble an ant in its configuration. It looked remarkably similar to some recent machines, and, despite its electromechanical simplicity, was capable of some relatively sophisticated behaviors [5–8]. In the same time frame, Okhotsimsky et al. also constructed a six-legged machine of generally similar geometry. Bessonov and Umnov numerically identified all the possible statically stable six-legged gaits and, more importantly, formulated the hexapedal wave gait family and demonstrated that they maximize the longitudinal stability margin [9]. Song and Waldron eventually provided a theoretical proof of this proposition [10].

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A little later, Hirose constructed the first of many Titan quadrupeds. This machine was mechanically sophisticated employing three-dimensional pantograph mechanisms in the legs. It provided a very early demonstration of stair climbing [11]. The first attempts to construct and operate a bipedal robot were those of Kato and his students at Waseda University [12]. This line of development has gone through many generations of machines and was ancestral to the genre of humanoid robots [13]. The Adaptive Suspension Vehicle was a large, six-legged vehicle designed to carry an operator and a 500 lb payload [14], and intended as a mobility system for use in very rough terrain (see Fig. 3). Although the operator commanded direction and speed of locomotion by means of a joystick, coordination of the machine was completely automated with the computer controlling gait (leg phasing) and foot placement [15]. It employed a very early version of a laser rangefinder to build a model of the terrain in front of the machine that was used both to control vehicle parameters such as body height, and pitch and roll attitudes, and to select foot placement locations. The machine geometry was designed to allow both efficient walking on easy terrain and maneuvering over large obstacles [16], and a sophisticated hydrostatic drive system was used to avoid the large energy losses inherent in the use of flow metering valves for control [17]. This machine, which first walked in 1985, was designed to operate in a statically stable mode [10]. This means that, in principle, if all actuators were frozen the machine would continue to stand stably. The equivalent concept for bipedal locomotion: controlling stability by means of the zero moment point goes back a very long way to the work of Vukobratovic and Juricic [18]. Static stability was inherent in McGhee and Frank’s work on quadrupeds [2], and on the work cited above on hexapods [9, 10].

Fig. 3  Adaptive suspension vehicle (1985)

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A very different mode of operation is that of machines that employ dynamically stable gaits. This line of research is associated with Raibert [19] who started with a simple, planar hopping system [20] and progressively elaborated it to a threedimensional hopper [21], then to a bipedal machine, and subsequently a quadruped [22]. All of these machines employed simple, telescoping legs with two degree of freedom connections at the hips to bodies with relatively high pitch and roll moments of inertia. This work produced a set of control laws that have been used, with minor modifications by most subsequent studies of dynamically stable locomotion, and amply demonstrated the potential of dynamically stable robots. This work included demonstration of all the symmetric quadrupedal gaits: pronk, bound, trot, pace, but not either form of gallop.

More Recent Achievements These machines were designed with specific sets of gaits in mind. Legged systems found in nature are significantly more versatile, but because of the difficulty in creating a legged system capable of both static and dynamically stable gaits, two design philosophies appeared the 1980s. One approach focused on developing robust statically stable gaits, generally through the use of precisely controllable, stiff drive mechanisms, and the other approach continued work into dynamic locomotion, often using compliant actuators. Honda’s secret development of its experimental “E” and prototype “P” bipedal legged platforms, along with their successor ASIMO, is a useful study in humanoid robot development, as they span several decades of cutting-edge legged robotics research that has large amounts of funding available to explore the newest technologies. All of Honda’s robots used stiff electric drive motors to control the joints, making precise foot placement and weight distribution possible, but not dynamic maneuvering. Following the successful 3  km/h walking speed of the E3 bipedal platform, Honda’s E4–E6 were concurrently created in 1991 to study autonomous walking over varied terrain; these 12-DOF bipeds carried onboard computers for autonomous operation. An offspring of these platforms, the first fully humanoid robot, the Honda P1 was unveiled in 1993 [23]. The P1 included 30 DOF, with autonomous operation possible for only several minutes. One of the larger influences on legged robot evolution through the 1990s was the increased available computational power, making fast control of kinematically complex machines possible in dynamic environments. Since controlling large numbers of joints through cluttered and changing environments requires searching disproportionately larger joint spaces, the computational load can be very high. ASIMO was created following the P3, with the 2005 version of ASIMO having 31-DOF not including those in the neck. ASIMO, seen in Fig. 4, is able to plan paths autonomously through dynamically changing spaces using an onboard camera and computer vision processing [24].

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Fig. 4  Honda ASIMO

Although ASIMO is touted as being able to successfully execute “human-like running” [25], this is not truly dynamic running in the biomimetic sense, but is a jog, or pseudo-run. The distinction is important: dynamic running involves a significant interplay between potential and kinetic energies throughout the gait cycle, resulting in substantial energy savings as energy is stored on impact and released on thrust. It is true that there is a different interplay between kinetic and potential energy during biomimetic walking. In running by a lossless system, in theory only the kinetic energy of the foot has to be replenished by the machine [26]. In contrast, in the quasi-static run that ASIMO executes, impact energy is lost on stiff actuators. Both biomimetic and pseudo-runs involve a flight phase, but only biomimetic running is sustainable for long periods of time with self-contained, untethered robots that must carry their own power supply. The requirement for legged robots to remain untethered is an important criterion that is not purely academic, given that the primary goal of such machines is to function outside the laboratory. Kawada’s HRP-2 (1997–2010, 28–42 DOF) [27], Sony’s QRIO in 2006 [28], the 2009 Toyota humanoid [29], and a myriad of many other self-contained humanoid robots have successfully implemented robust quasi-static walking and jogging gaits, using primarily Zero Moment Point based gait generation. QRIO’s implementation includes three separate microcontrollers operating different aspects of the robot [28] resulting in simultaneous processing of visual data and motion

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algorithms, allowing QRIO to become the first bipedal running robot as credited by the Guinness Book of World Records. It must be noted, though that the latter’s definition of running is simply “moving while both legs are off the ground at the same time”, ignoring any details necessary for true dynamic running. Additionally, with stiff actuators, there are strictly defined ways in which a robot can “run”, and if operation outside those realms is desired, a different approach to actuating the robots must be undertaken. The additional practical requirement for small duty factors while running calls for robots that have sufficiently long flight times (compared to contact times) to clear obstacles; this occurs naturally when potential and kinetic energies are efficiently exchanged. However, because of their stiff drive mechanisms, ASIMO and QRIO have large duty factors near 0.8, and their flight time of 80 ms causes only a few millimetres clearance from the ground [30]. Toyota’s humanoid has a 0.7 duty factor with a few millimetres clearance when at a 7 km/h velocity [29]. In contrast, humans run at 0.35 [31], and can easily clear obstacles several tens of centimetres in height. Since stiff actuators limit the dynamic behaviour of legged machines, a second branch continued work on legged systems with more naturally behaving leg systems. In animals, most transitions between gaits occur when it is energetically beneficial to switch gaits. In other words, a horse switches between a trot and a gallop, since maintaining a trot gait at a gallop velocity would require more energy than a gallop gait would. As can be guessed, due to the differing dynamics of variously sized animals, the optimal transition velocities should be different. More precisely, the dimensions of the animal, and its corresponding optimal gait transitions, are closely related. Several factors can roughly predict this velocity, most famously the Froude number. The Froude number relates the leg length to the potential energy of the system, from which it is evident that it’s worth considering the natural pendulum-like dynamics of a leg. A pendulum with a short length has a fast natural swing resonance; if an actuator drives the joint at that frequency, very little additional energy is required to maintain the swing. Likewise, a long leg has a slower natural swing frequency. With either pendulum length, more energy is required to maintain a swing faster or slower than the natural frequency. Among others, McGeer noticed this correlation with energy consumption and walking speed. His 1990 Passive Dynamic Walker used no actuators, but could walk robustly down a 3° incline by utilizing the natural swing frequency of the legs [32]. Several so-called Compass Gait bipeds were built around this philosophy [33]. In these designs, only weak motors are needed to allow the same passive system to walk on a level surface. This work continues to inspire a new generation of robots, notably Collins’ 3D Passive Walker that is able to walk on a level surface using a very simple control algorithm that simply swings the legs at appropriate times; roll and yaw compensation occurs with added arm linkages that are mechanically constrained in specific ways, instead of software control, as well as a carefully designed foot geometry [34]. This robot holds the current world record for distance travelled by a bipedal robot in one trial, at approximately 9 km (Boston Dynamics’ BigDog holds the record for quadrupedal robots, at 10 km [35]). Although passive walkers

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exhibit impressively natural walking gaits, they are not equipped for truly dynamic maneuvers such as jumping and running. For this a different design of robot is needed. Static stability is a characteristic of most multi-legged robots, including many that have been applied in practice, such as the several versions of Dante [36]. These actually represent a different genre of walking machines that are in no way biomimetic. Dante is an eight-legged frame-walker in which two sets of simple, one degree of freedom legs are mounted to two sub frames that can be moved relative to each other. This is a way of minimizing the number of active degrees of freedom needed (ten for Dante) while maximizing the number of legs. Dante was operated on a tether to rappel into the cone of the active volcano Mt. Spur in Alaska to collect samples of volcanic gas. Dynamic maneuvering remains one of the last basic hurdles for legged robots. It is a complex task given the varied architectures of robots, where the particular system’s dynamics dictates the type of gait and control that may be used. Raibert’s dynamic robots required a very particular geometry in which the torso had a high moment of inertia compared to the legs [20]. Similarly, the robot Rabbit is operated by a controller based on a model optimized for that particular machine [37]. Raibert’s prismatic-legged 3D bipedal runner, shown in Fig. 5, was able to achieve unlimited stable running, limited only by practicality. This in part because prismatic legged locomotion is simpler due to the dynamics of linearly thrusting legs.

Fig. 5  Raibert’s 3D bipedal runner

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All are highly successful robots and are models of aggressive research, however, some theorize that these are designed in contrast to natural systems, where very similar algorithms could be used in all legged machines, and that it’s passive mechanical stabilization that actually creates the robustness. Consider an arbitrary hexapedal dynamic gait. The system can be constructed so that if the legs freeze mid-stride, the system will settle into a stable upright position given that the Zero Moment Point (ZMP) resides within the so-called Support Pattern. Said another way, irrespective of the terrain it is traversing, whether the feet arrive later or earlier than anticipated, a statically stable machine remains upright. This is one of the advantages of hexapedal machines such as the ASV, notwithstanding the intelligence built into them. However, during dynamic quadrupedal gaits, for example during a trot, if legs are frozen at an arbitrary phase, the machine will in general settle to an unstable position and tip over when inertial forces are added into the picture. (With low inertial forces of a specifically designed quasistatic gait, a quadruped may also have its ZMP inside its support pattern at all times, even in the presence of disturbances). Similarly, by nature having only one support leg at any given time during dynamic gaits, without active compensation bipedal systems would fail to remain upright in the presence of disturbances. In contrast to the stiff actuators of quasi-static locomotion, dynamic legged locomotion can benefit greatly from compliant actuators. In the words of Gill and Jerry Pratt, “Stiffness isn’t everything”, and the bandwidth of an actuator may be a secondary consideration to the low-pass filtering of shock loads that are automatically accomplished through the use of elastic components [38]. Such an actuator could be a combination of a stiff and elastic element, such as Pratt’s Series Elastic Actuator invented in 1995, used on robots such as COG and Spring Turkey [38], and M2 [39], or an inherently elastic actuator such as pneumatic cylinders. Blackwell’s bipedal Dexter designed in 2002 uses pneumatics for all joints [40]. There is strong evidence that elasticity plays a key role in stable dynamic legged locomotion [41] as muscles and tendons are elastic by 2% and 10%, respectively (it is still unclear which effect, if not both, is dominant), lowering the cost of locomotion by storing impact energy in these muscle-tendon series elastic actuators. When selected properly, elasticity can increase the actuator’s bandwidth as well [39]. With the “Cost of Dynamics” reduced through energy capture and release [42], elastic actuators offer one potential solution to stable dynamic maneuvers. It has been shown that utilizing the natural dynamics of the system allows actuator power consumption to be minimal. One example is the 2001 Cornell 3D Biped, which consumes 3W during walking gaits; this is almost as low as the potential energy lost during a stride [26]. The same strategy can be applied to dynamic gaits. Seyfarth’s JenaWalker II uses springy tendons that couple several joints, and achieves walking gaits by driving only the two hip motors; by tuning the elasticity, small flight phases can be observed [43]. Muscle-tendon combinations in which the actuator (muscle) is mounted remotely and activates the joint by force transmission through an elastic element (tendon) reduce the energetic cost of dynamic locomotion. The moments of inertia of swung limbs are reduced. Remote actuator placement is widely utilized in legged

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robotics, as it allows for smaller and lighter actuators. Rabbit used this approach for its knee actuators, and all six of Spring Flamingo’s motors were placed in the torso, and actuated the joints via cables [44]. For those biomimetic legs that use remote joint powering, questions arise: How should the force be transferred between the joints of a leg? Is it necessary that all joints be powered? In nature, there is often significant coupling between joints [45], and some designs favour driving multiple joints with one actuator. This takes the inertia reduction strategy one step further, and may eliminate the mass of an actuator altogether. Collin’s 3D Biped uses a motor actuating the ankle via a springy cable to provide toe-off torque. The KenKen series of small monopedal and bipedal robots removes the actuator, and simply uses springs coupled between the heel and quad. This arrangement allows for the storage and efficient release of impact energy [46]. In the multi-legged domain, in 2006 the dynamic KOLT quadruped used air reservoirs and valves to store impact energy from pneumatic cylinders, releasable on thrust. The knee joints were positioned via cables wound around remotely located electric motors [47]. These strategies reduce inertia, and minimize the required actuator power due to energy storage capabilities. However, passive stability is one of the keys to achieving dynamic gaits, at least in small systems [41]. Here the system’s kinematic configuration alone can result in self-stabilizing behaviour that does not require the intervention of a controller. Some intelligence can be built into the leg materials. Several robots have been constructed with material intelligence. Since elastic actuators help with passive stability, the legs of Cutkosky’s iSprawl hexapods were designed with materials with specifically tuned compliances, reducing the effects of perturbations on the system [48]. Biomimetic robot leg kinematic configurations can also be beneficial. The TRIP planar dynamic biped uses an inelastic tendon to couple the actively driven knee and passive ankle joints; the amount of coupling automatically changes with the landing position of the foot [49]. If the foot lands behind the desired point, the leg naturally swings forward on thrust into a more stable position, and vice versa if the leg lands forward of the target. Varying the length of the tendon changes the target position that the leg tends to swing towards, similar to how muscles reposition tendons depending on the gait. JenaWalker II uses small servomotors to adjust the compliance of their coupling cables; by changing the compliance, the stride frequency can be changed, a capability not found in other passive walkers that are fixed to the one stride frequency [43]. Regardless of the specific gaits of the robot, the true benefit of legged machines come from their ability to negotiate rugged terrain outside the laboratory. Cutkosky’s RiSE and Stickybot climbing robots have demonstrated the ability to climb vertical surfaces such as trees and sheetrock via dozens of biologicallyinspired claws on each foot [50], as well as vertical glass (Fig. 6) using material cohesion from thousands of miniature hairs similar to that found on a Gecko’s foot [51]. The past several years has also seen the marketing of robots suitable for realworld use. In part this is due to the maturation of actuation and battery technology, which allows for lighter machines.

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Fig. 6  Stickybot ascending glass, and RiSE climbing brick (2008)

Boston Dynamics’ Big Dog (Fig. 7) is a truly rugged dynamic legged system. Created for DARPA in 2006, it is able to trot and bound through unstructured terrain, recover from including kicks and slipping on ice, and can climb steep slopes [35]. Powered by an internal combustion engine and hydraulic actuators, this system is self contained and powerful enough to carry 140  kg loads and execute dynamic gaits. One of the prime potential uses of legged machines is as assistive devices for those who are disabled or carrying heavy loads. Introduced in 2009, the 6.5  kg Personal Bodyweight Support Assist system by Honda incorporates two low-profile semi-active robot legs that the user places in parallel with their legs; using two electric motors at the hips, the system is able to assist the human’s power in static gaits in varying structured terrain including stairs [52]. After Berkeley’s BLEEX lower-body exoskeleton’s successful prototype in 2000, the company Berkeley Bionics produced several exoskeletal systems capable of carrying up to 90 kg beyond their own weight, reducing the oxygen consumption of the user by at least 15% for heavy loads [53]. The joints are powered by hydraulics, and the entire system is run on chemical batteries, soon to be replaced by a fuel cell for several-day operation times. In contrast, Cyberdyne’s 23 kg full-body HAL exoskeleton uses electric motors controlled by nerve impulses. Revealed in 2006, HAL currently runs for 5  hours under battery power, but its unique ability is to operate autonomously without a host through motions learned while operating with a human wearer.

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Fig. 7  Bigdog by Boston dynamics

In 2005, Timberjack’s fully functional prototype hexapedal Walking Tree Harvester was able to traverse uneven terrain to reach trees with minimal environmental impact due to its ability to place feet carefully at desired locations [54]. The forward leg pair has forward facing knees, while the two aft pairs have their knees pointing backwards; the middle pair has flipped knees compared to the ASV. There are a number of issues which prevent legged machines from being more readily available for real-world use. Power source options are limited for small, nonpassive humanoid-scale robots, thus far making them suitable only for demonstration. The operation time for bipeds like ASIMO and HRP are 1–2 h at most. Internal combustion engines are an option where high power is required, and noise and emissions are not a restriction. Boston Dynamics’ bipedal robot, Petman, is essentially half of BigDog, and as such uses an internal combustion engine to power its hydraulics [55]. This is not acceptable for interior environments. With larger machines, operated outdoors, engines are a popular option. Timberjack, the ASV, and Bigdog all use internal combustion engines. The power densities of electric actuators and internal combustion engines are similar, but the energy density of liquid fuel is an order of magnitude greater than that of the most advanced chemical battery technologies [56].

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Actuator technologies are the limiting factor in the introduction of small legged machines that seek to maneuver as mammals do. A few technologies have been developed to attempt to incorporate some of the best characteristics of mammalian muscle. Braided pneumatic actuator muscles, such as Festo’s Fluidic Muscles, attempt to mimic muscle with their powerful contraction when provided with compressed air [57]. Pleated pneumatic muscles do not suffer from the detrimental frictional side-effects or hysteresis of the braided devices [58]; this is one of the reasons Daerden’s 2005 walking biped Lucy was powered by pleated air muscles [59]. Although these actuators can accomplish high position precision with light loads, they are highly nonlinear and are difficult to accurately control.

Conclusions We have presented a brief review of what is now a voluminous literature on legged robotics. As an organization, IFToMM has played a central role in this story, a role that can be expected to continue to evolve with the field in the future. Acknowledgement  The authors acknowledge the support of the National Science Foundation grant number CMMI-0825364.

References 1. Frank, A.A.: Automatic control systems for legged locomotion. USCEE Report No. 273, University of Southern California, Los Angeles (1968) 2. McGhee, R.B., Frank, A.A.: On the stability properties of quadruped creeping gaits. J. Math. Sci 3(3–4), 331–351 (1968) 3. Baldwin, W.C., Miller, J.V.: Multi-Legged Walker, Final Report. Space General Corporation, El Monte (1966) 4. Liston, R.A., Mosher, R.S.: A versatile walking truck. In: Proceedings. 1968 Transportation Engineering Conference. ASME-NYAS, Washington, D.C., (1968) 5. McGhee, R.B., Orin, D.E.: A mathematical programming approach to control of joint positions and torques in legged locomotion systems. ROMANSY 2, Warsaw (1976) 6. McGhee, R.B., Iswandhi, C.I.: Adaptive locomotion of a multilegged robot over rough terrain. IEEE Trans. Syst. Man Cyber. 9(4), 176–182 (1979) 7. Klein, C.A., Olson, K.W., Pugh, D.R.: Use of force and attitude sensors for locomotion of a legged vehicle over irregular terrain. IJRR 2(2), 3–17 (1983) 8. McGhee, R.B., Orin, D.R., Pugh, D.R., Patterson, M.R.: A hierarchically-structured system for computer control of a hexapod walking machine. In: RoManSy, Hermes, London, pp. 375–381 (1985) 9. Bessonov, A.P., Umnov, N.V.: The analysis of gaits in six-legged vehicles according to their static stability. RoManSy 1, pp. 1–10, vol. 1. Elsevier, Amsterdam (1973) 10. Song, S.M., Waldron, K.J.: An analytical approach for gait study and its applications on wave gaits. IJRR 6(2), 60–71 (1987) 11. Hirose, S., Umetani, Y.: The Basic Motion Regulation System for a Quadruped Walking Machine. ASME Paper 80-DET-34, DETC, Los Angeles, (1980)

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12. Kato, I., Tsuiki, H.: The hydraulically powered biped walking machine with a high carrying capacity. In: IV Symposium on External Control of Human Extremities, Dubrovnik (1972) 13. Kemp, C.C., Fizpatrick, P., Hirukawa, H., Yokoi, K., Harada, K., Matsumoto, Y.: Humanoids. In: Siciliano, B., Khatib, O. (eds.) Handbook of Robotics, pp. 1307–1334. Springer (2008) 14. Pugh, D.R., Ribble, E.A., Vohnout, V.J., Bihari, T.E., Walliser, T.M., Patterson, M.R., Waldron, K.J.: Technical description of the adaptive suspension vehicle. IJRR 9(2), 24–42 (1990) 15. Song, S.M., Waldron, K.J.: Machines that Walk: The Adaptive Suspension Vehicle. MIT Press, Cambridge, Mass (1989) 16. Song, S.M., Waldron, K.J.: Geometric design of a walking machine for optimal mobility. J. Mech. Transm. Autom. Des. 109(1), 21–28 (1987) 17. Waldron, K.J., Pery, A., McGhee, R.B., Vohnout, V.J.: Configuration design of the adaptive suspension vehicle. IJRR 3(2), 37–48 (1984) 18. Vukobratovi´c, M., Juriˇci´c, D.: Contribution to the synthesis of biped gait. IEEE Trans. Biomed. Eng. 16(1), 1–6 (1969) 19. Raibert, M.H.: Legged Robots that Balance. MIT Press, Cambridge (1986) 20. Raibert, M.H., Brown Jr., H.B.: Experiments in balance with a 2D one-legged hopping machine. ASME J. Dyn. Syst. Meas. Control 106(2), 75–81 (1984) 21. Raibert, M.H., Brown Jr., H.B., Chepponis, M.: Experiments in balance with a 3D one-legged hopping machine. IJRR 3(2), 75–92 (1984) 22. Raibert, M.H.: Running with symmetry. IJRR 5(4), 3–19 (1987) 23. Honda Motors Co., P1-P2-P3 History of Humanoids: [online], Available from: http://world. honda.com/ASIMO/history/p1_p2_p3.html. Accessed 20 Apr 2010 24. Michel, P., Chestnutt, J., Kuffner, J.J., Kanade T.: Vision-guided humanoid footstep planning for dynamic environments. In: Proceeding IEEE/RAS International Conference, Humanoid Robotics, pp. 13–18 (2005) 25. Honda Motors Co., ASIMO Frequently Asked Questions: [online], Available from: http:// asimo.honda.com/downloads/pdf/asimo-technical-faq.pdf. Accessed 20 Apr 2010 26. Dickinson, M.H., et al.: How animals move: an integrative view. Science 288(5463), 100–106 (2000) 27. Kaneko, K., et al.: Humanoid robot HRP-2. ICRA 2, 1083–1090 (2004) 28. IEEE Spectrum Inside Technology, QRIO: The Robot That Could: http://spectrum.ieee.org/ robotics/robotics-software/qrio-the-robot-that-could Accessed 20 Apr 2010 29. Artificial Intelligence and Robotics, Toyota’s Running Humanoid robot: http://smart-machines. blogspot.com/2009/07/toyotas-running-humanoid-robot.html. Accessed 20 Apr 2010 30. Honda Motors Co., New Asimo – running at 6  km/h: http://world.honda.com/hdtv/asimo/ new-asimo-run-6kmh. Accessed 20 Apr 2010 31. Fihl, P., Moeslund, T.B.: Classification of gait types based on the duty-factor. In: Proceeding IEEE Conference on Advanced Video and Signal Based Surveillance, pp. 318–323 (2007) 32. McGeer, T.: Passive dynamic walking. IJRR 9(2), 62–82 (1990) 33. Collins, S.H., et  al.: Efficient bipedal robots based on passive-dynamic walkers. Science 307(5712), 1082–1085 (2005) 34. Collins, S.H.: A three-dimensional passive-dynamic walking robot with two legs and knees. IJRR 20(7), 607–615 (2001) 35. Boston Dynamics, BigDog – The Most Advanced Rough-Terrain Robot on Earth: http://www. bostondynamics.com/robot_bigdog.html. Accessed 20 Apr 2010 36. Bares, J.E., Whittaker, W.L.: Configuration of autonomous walkers for extreme terrain. IJRR 12(6), 535–559 (1993) 37. Chevallereau, C., et al.: RABBIT: a testbed for advanced control theory. IEEE Control Syst. Mag. 23(5), 57–79 (2003) 38. Pratt, G. et al.: Stiffness isn’t everything. In: Proceedings of ISER, pp. 253–262 (1995) 39. Robinson, D.W. et al.: Series Elastic Actuator Development for a Biomimetic Walking Robot. 1999 IEEE/ASME AIM, pp. 561–568, Atlanta (1999)

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40. AnyBots, Inc., About the Robots: http://www.anybots.com/abouttherobots.html. Accessed 20 Apr 2010 41. Alexander, R.M.: Elastic Mechanisms in Animal Movement, p. 47. Cambridge University Press, Cambridge (1988) 42. Tucker, V.A.: The energetic cost of moving about. Am. Sci. 63(4), 413–419 (1975) 43. Seyfarth, A., et al.: Towards bipedal jogging as a natural result of optimizing walking speed for passively compliant three-segmented legs. IJRR 28(2), 257–265 (2009) 44. Pratt, J., Pratt, G.: Intuitive control of a planar bipedal walking robot. In: ICRA, pp. 2014–2021 (1998) 45. Alexander, R. M.: Elastic mechanisms in animal movement. Cambridge, p. 37 (1988) 46. Hyon, S., Mita, T.: development of a biologically inspired hopping robot–Kenken. ICRA, pp. 3984–3991 (2002) 47. Estremera, J., Waldron, K.: Thrust control, stabilization and energetics of a quadruped running robot. IJRR 27(10), 1135–1151 (2008) 48. Kim, S., et  al.: iSprawl: design and tuning for high-speed autonomous open-loop running. IJRR 25(9), 903–912 (2006) 49. Csonka, P., Waldron, K.: Static and dynamic maneuvers with a tendon-coupled biped robot. In: Proceeding RoManSy (2010) 50. Kim, S., Asbeck, A., Provancher, W., Cutkosky, M.: SpinybotII: climbing hard walls with compliant microspines. ICRA 2005, 18–20 (2005) 51. Kim, S., et  al.: Smooth vertical surface climbing with directional adhesion. IEEE Trans. Robot. 24(1), 65–74 (2008) 52. Honda Motors Co., Walking Assist Device with Bodyweight Support System: http://corporate. honda.com/innovation/walk-assist/. Accessed 20 Apr 2010 53. Bogue, R.: Exoskeletons and robotic prosthetics: a review of recent developments. Ind. Robot: Int. J. 36(5), 421–427 (2009) 54. Space.com, Tech Today: Walking Forest Machine: http://www.space.com/techtoday/ tech_today_walker.html. Accessed 20 Apr 2010 55. Boston Dynamics, PETMAN – BigDog gets a Big Brother: http://www.bostondynamics.com/ robot_petman.html. Accessed 20 Apr 2010 56. Marc, Zupan, Ashby, M.F., Fleck, N.A.: Actuator classification and selection – the development of a database. J. Adv. Eng. Mater. 4(12), 933–940 (2002) 57. Festo Corp, Fluidic Muscle: http://www.festo.com/net/en-us_us/downloads/downloadcache. ashx?lnk=26780/info_501_en.pdf. Accessed 20 Apr 2010 58. Daerden, F. et al.: Pleated pneumatic artificial muscles: actuators for automation and robotics. In: Proceeding. 2001 IEEE/ASME AIM, pp. 738–743, vol. 2 (2001) 59. Verrelst, B., et  al.: The pneumatic biped “lucy” actuated with pleated pneumatic artificial muscles. Autonom. Robots 18(2), 201–213 (2005)

Part II

Viewpoints by Chairs of IFToMM Technical Committees and Permanent Commissions

The History of Mechanism and Machine Science (HMMS) and IFToMM’s Permanent Commission for HMMS Teun Koetsier, Hanfried Kerle, and Hong-Sen Yan

Abstract  In this paper we put machines and mechanisms, Mechanism and Machine Science (MMS) and the foundation of the International Federation for the Theory of Machines and Mechanisms (IFToMM) in the wide perspective of the economic history of the world and we devote some attention to the activities of IFToMM’s Permanent Commission for the History of MMS.

Introduction The First Industrial Revolution is synonymous with mechanization, with the replacement of human labor by machine labor. Machines had been important economically for many centuries but in the second half of the eighteenth century something dramatically changed. Before the First Industrial Revolution world wide agrarian societies had been caught in what is often called the Malthusian trap: technological advances did not lead to more wealth for the average person. During the First Industrial Revolution machines contributed heavily to the efficiency level of the industrializing societies and in these countries wealth increased immensely.

T. Koetsier (*) Department of Mathematics, FEW, VU University Amsterdam, De Boelelaan 1081, NL-1081HV Amsterdam, The Netherlands e-mail: [email protected] H. Kerle Institut für Werkzeugmaschinen und Fertigungstechnik, TU Braunschweig, Langer Kamp 19b, D-38106 Braunschweig, Germany e-mail: [email protected] H.-S. Yan Department of Mechanical Engineering, National Cheng Kung University, 1, University Road, Tainan 701-01, Taiwan e-mail: [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_6, © Springer Science+Business Media B.V. 2011

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In the nineteenth century the theory of machines and mechanisms (MMS) developed into a coherent whole and when, during the Second Industrial Revolution, scientific technology led to a new phase of spectacular industrial development MMS played an important role. Efficiency in the industrialized nations rose to unprecedented levels and so did the sophistication of the design of machines and mechanisms. The foundation in 1969 of the International Federation for the Theory of Machines and Mechanisms (IFToMM) was an expression of the great interest that existed at the time in the theory of machines and mechanisms. In this paper we briefly put the foundation of IFToMM in a wide perspective and we devote some attention to the activities of IFToMM’s Permanent Commission for HMMS.

The Industrial Revolution In A Farewell to Alms, a Brief Economic History of the World, [1], Gregory Clark depicted the economic history of the world in one picture. See Fig. 1. The picture shows that before 1800, in spite of all the technological advances, there was no upward trend in the average income per person. Clark adds that there was no improvement on other levels either. For example, the life expectancy in 1800 was still 30–35 years, not different from the life expectancy of gatherers and hunters in 10,000 BC. This situation changed radically with the series of dramatic developments in the period 1760–1830 in England that is often called the Industrial Revolution. With the Industrial Revolution the average income per person started to rise drastically in the countries that participated in this development.

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What happened during and after the Industrial Revolution? Economically something changed. What was it?

The Escape from the Malthusian Trap Before 1800 the rate of technological advance was low. According to Clarke this led to a situation in which technological progress merely led to a growth of the population. Thomas Malthus (1766–1834) had argued that a population has the inclination to grow geometrically, while the production of food grows only arithmetically. This inevitably leads to a large population living at a subsistence level. This situation is often called the Malthusian trap. During the Industrial Revolution in England an escape from the Malthusian trap took place. In the period 1870–1860 the English population tripled, while at the same time real incomes rose. This development continued until the present. Productivity has increased immensely and although there was an enormous growth of the industrial sector, for example, steelworks and cotton mills, since 1800 the productivity of agriculture has increased by as much as the rest of the economy. What happened? Why did material well-being increase so dramatically in the industrialized countries? The answer is that the past two centuries have shown an enormous increase in the efficiency of the production process. Land per person, the decisive factor in the Malthusian economy, is no longer crucial. It is the investment in expanding the stock of knowledge involved in the production. In the 1950s the economist Robert Solow developed a macro economic model for the description of economic growth that very well describes what happened, first in England and later in other countries. In 1990 Solow received a Nobel Prize for this work. See Fig. 2. The input variable land C includes all natural resources. The output is a function of C, L and K: Y = A F (C, L, K )





Land C Inputs

Labor L Capital K

Fig. 2  Production: the essential variables

Production

Output Y

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The factor A measures the efficiency level of a society. Before the Industrial Revolution A did not rise enough to get out of the Malthusian trap. During the past two centuries, however, A has grown dramatically. How come? I will argue that the introduction of the large scale use of machines was an absolutely crucial factor.

The Background of the Industrial Revolution The Industrial Revolution was a highly complex development. Let us have a very brief look at some of the aspects. Crucial factors in the development towards the Industrial Revolution were the growing role of the entrepreneur and the money economy. The discovery of the New World played an important role in this respect. This discovery was in its turn the result of technological progress. Without advances in navigation and shipbuilding the opening up and the exploitation of the new trade routes to America, India and China would not have been possible. The compass was introduced at the end of the twelfth century, which made it safer to navigate far beyond the sight of land. The sternpost rudder was introduced and replaced steering oars. Multiple masts and multiple sails on one mast were introduced. Before the end of the fifteenth century the ship had almost reached the form it retained until the nineteenth century. The steering wheel was introduced later [13]. In the sixteenth, seventeenth and eighteenth centuries we see all over Western Europe a growth of trade and technological progress (Fig. 3). The steady flow of huge quantities of gold and silver from the New World led already in the Renaissance to a considerable growth of the money economy. An economy that functions on the basis of barter is not as flexible as a money economy. The money economy, however, also led to waves of inflation. This development continued in the seventeenth and eighteenth centuries. Moreover, in the background of the Industrial Revolution there were ideological changes. The Protestant Reformation and the Scientific Revolution led to a different attitude towards traditions and a more positive attitude towards planning and innovations.

The Machines The growth of the production output of a country as a result of growth of the factor A that measures the efficiency of the economy is often called the Solow residual. Although much was happening in the seventeenth and first half of the eighteenth century the efficiency of the English economy only grew slowly. This changed with the Industrial Revolution in the second half of the eighteenth century. The introduction of

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Agricultural Revolution

Technological progress in the Late Middle Ages and the Renaissance: navigation, shipbuilding, printing

Discovery of the New World: New Frontiers, Gold and Silver, Trade

Appearance of the entrepreneur and the money economy

The Industrial Revolution: fast rise of the level of efficiency of the society and a high rate of technological innovation

Ideological changes: positiev attitude towards planning and innovation

Protestant Reformation Scientific Progress

Scientific Revolution

Fig. 3  Some long term lines of influence ending in the industrial revolution (Inspired by http:// www.unc.edu/~nielsen/soci111/)

large scale use of machines that were improved again and again was one of the major factors contributing to the growth of the Solow residual. The Industrial Revolution is practically synonymous with mechanization, with the replacement of human labor by machine labor. In the course of time horse power and water power were replaced by machines as well. Let us briefly consider two classical examples (Fig. 4). In 1712 Thomas Newcomen had invented a steam engine that was used to pump water out of mines. A growing demand for coal and (iron) ore had led to deeper mines and this in its turn had led to a demand for better pumps. In Newcomen’s engines the cylinder and the pump were separated. The steam was used to create a vacuum. The atmospheric pressure made the piston move. These machines were

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Fig. 4  Left Newcomen’s engine; Right Watt’s engine (Source: http://www.uh.edu/engines/epi69.htm)

often used in the second half of the eighteenth century. In 1769 Watt obtained a patent on an improved steam engine in which the condensator and the cylinder were separated. This saved energy. A patent from 1782 concerned a double-acting engine: the steam was used to push the cylinder in two opposite directions: upwards and downwards. Although Newcomen’s engines continued to be used for quite some time, Watt’s engines won in the end. Other inventions played a role in the Industrial Revolution as well. In 1733 John Kay patented the flying shuttle which made it possible for one weaver to do the work formerly done by several. The result was that spinners could not keep up with the yarn. This led to a problem: How can we make the spinning more efficient? In 1764 James Hargreaves built the ‘Spinning Jenny’, a whole line of spindles was worked by one wheel (Fig. 5). Yet the cotton yarn produced by the spinning Jenny was coarse and several new inventions were necessary before this was remedied. The result was so successful that soon the looms turned out to be too slow to process the yarn produced by the spinning machines. This led to several new improvements in looms. Originally the machines in the textile industry were driven by means of man power, water power or horse mills. The machines became heavier and in the last decades of the eighteenth century steam engines were used.

The Rise of Mechanism and Machine Science Mechanism and Machine Science (MMS) has roots that go back until the Greeks. A lovely example is the theory of the basic machines: lever, wheel and axle, pulleys, wedge and screw. This theory was born in Antiquity. However, the Ancients

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Fig. 5  Spinning Jenny: An engraving of a Spinning Jenny by T. E. Nicholson (1835) (Source: http://www.spartacus.schoolnet.co.uk/TEXjenny.htm)

did not fully understand the wedge and the screw. Galileo Galilei was the first to succeed in finishing the theory of the basic machines. Yet understanding the functioning of a steam engine requires much more than merely the theory of the basic machines and only in the nineteenth century MMS reached the level of a coherent scientific discipline. It all started with the foundation of the École Polytechnique in Paris in 1794. Before 1794 the theory of mechanical engineering consisted in fact of isolated results. After 1794, serious attempts were made to turn MMS from a collection of isolated results into a coherent subject of research. MMS was not yet viewed as a separate scientific discipline, but Gaspard Monge, who was in charge of the École Polytechnique, decided that a course on machine elements had to be included in the curriculum of the school. J. Hachette was given the task of preparing a text. The wellknown system of classification of the mechanisms (that were called ‘elementary machines’ at the time) had a central position in the course. There are four kinds of movements of the input and of the output: Continuous circular Alternating circular Continuous rectilinear Alternating rectilinear. This yields ten types of elementary machines. This system of classification, invented presumably by Monge, was first published with a full description of all mechanisms in 1808 under the title Essai sur la composition des Machines and prepared by the gentlemen Lanz and Bétancourt under the supervision of Hachette. Hachette’s own textbook, the Traité élémentaire des machines, appeared in 1811.

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Franz Reuleaux In the course of the nineteenth century the subjects covered nowadays by the terms kinematics of mechanisms and theoretical kinematics flourish. The 1970s and 1980s of the nineteenth century represent in this respect a golden age. At the same time the industrial revolution led to a continuous stream of new mechanisms and machines. In particular in Germany there was a keen awareness of the need to put the training of mechanical engineers on a better scientific basis. On the whole Germany, because of the number of its universities, its Technische Hochschulen, and its scientific literature tended in particular in the second half of the century more and more to dominate the scientific world. In precisely this period MMS emerges as a separate discipline. One of the dominating theoreticians was Franz Reuleaux, who argued that the machine is in the development of mankind the essential element that determines man’s relation with nature. He also emphasized the need for an independent, unified science of the machine. Like other sciences this science would reserve a precise place for its application. It is no exaggeration to say that Reuleaux was the first to define MMS as a separate discipline with kinematics of mechanisms at its core ([2] and [3]). Reuleaux started to develop his revolutionary ideas in the 1860s, and in 1875 his Theoretische Kinematik: Grundzüge einer Theorie des Maschinenwesens appeared in which for the first time a coherent theory of machines was developed. Reuleaux distinguishes motion as it appears in machines from the way it appears in nature. A machine is a device designed to bring about motion of an absolutely defined kind. While in nature disturbing forces usually immediately affect the motion of an object, machines are designed to resist disturbing forces and to exclude the possibility of any other than the wished-for motion. It is precisely the way in which in a machine the wished-for motion is brought about that becomes Reuleaux’ major preoccupation. He is the first to consider this problem in a general way, independent of specific machines. Reuleaux gives the following definition of kinematics: It is “the study of those arrangements of the machine by which the mutual motions of its parts, considered as changes of position, are determined” ([4], p. 40). Consequently kinematics is viewed by Reuleaux as essentially belonging to the science of machines and not to mechanics. Aiming to make the science of machinery deductive ([4], p. 22) Reuleaux attempts to reduce kinematics to simple fundamental truths. One of those fundamental truths is the following. A machine consists of parts. These parts are prevented from making any other than the required motion by other parts in contact with them. These considerations lead him to the well-known notions like pair of elements and kinematic chain. Eugene S. Ferguson wrote in 1963 about Reuleaux’ book: “Many of the ideas and concepts introduced in this book have become so familiar to us that we are likely to underestimate Reuleaux’ originality and consider him merely a recorder of the obvious”. ([4], p. v) and he added: “While the concepts are few and simple, it is instructive to note that they establish the point of view from which we contemplate mechanisms today” ([4], p. vi). Ferguson summarized Reuleaux’ contributions as

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follows: Reuleaux was the first to recognize that the fixed link is kinematically the same as any of the moving links, which resulted in the powerful concept of the inversion of linkages. Moreover, Reuleaux’ classification of mechanical components returned in many subsequent books on kinematics and machine design. Finally Reuleaux was one of the first to discuss the possibilities of synthesis: the systematic approach to the design of mechanisms to perform a given function. Yet we must emphasize that Reuleaux was not the only kinematician in the nineteenth century. Many brilliant mathematicians and engineers were involved in research concerning machines, in particular in Great Britain, in France, in Germany, in Austria, in Russia and in Italy. Reuleaux’s essentially simple ideas on mechanisms gave coherence the subject, which is what it needed because there are many different kinds of mechanisms that can be studied from many different points of view.

The Twentieth Century and the Nature of MMS The period 1880–1914 is sometimes called the Second Industrial Revolution. On the one hand, new technologies like electricity, the internal combustion engine, better steel, new alloys and chemicals and communication technologies such as the telegraph and the radio, led to greater productivity. On the other hand, machines continued to play an essential role. Moreover, mechanical engineering was becoming more and more scientific. In this period the beautiful theories developed by Reuleaux and others slowly gained importance. Germany took the lead in this respect in the 1920s. Machines had contributed essentially to the growth of the Solow residual during and after the First Industrial Revolution. The theories of machines played an essential role after the Second Industrial Revolution. MMS had become a serious economic factor. What is MMS? Let us start with some remarks on mechanical engineering. Clearly the ultimate goal of mechanical engineering is the design and the production of machines that satisfy certain requirements. In the methodology of mathematics, physics and chemistry there is considerable emphasis on methods that can be used to show that a theorem is true, or that a law of nature holds. There is less attention for heuristics. In mechanical engineering the situation is different. Criteria to determine whether a particular machine functions or will function in a reliable and efficient way are, of course, important. Yet, because the ultimate goal in mechanical engineering is the design and the production of machines, inevitably the question, “How do you, given certain requirements, design a machine”? will repeatedly be asked. Although a complete answer to this question in its general form is obviously impossible, in mechanical engineering there must be considerable attention for all kinds of methods that can be used to answer more specific design requirements. Another difference between mechanical engineering and science is that mechanical engineering is multidisciplinary. Unlike science mechanical engineering primarily deals with artifacts, entities that are man-made. New inventions and new technologies

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can lead to changes in existing machines or to the introduction of new machines. Because machines are functioning in the real world the many different aspects that they possess are in principle all important. Machines do not only have mathematical, physical and chemical aspects, but economic, legal and other cultural aspects as well. The result is that the notion ‘best possible machine’ is in principle not only dependent on new developments in the sciences, but in addition on, for example, the introduction of new laws or economic developments. The laws of nature are independent of human institutions, but yesterday’s best possible machine can easily cease to be the best possible machine today because of external developments. Reuleaux viewed MMS with kinematics as its core sub-discipline as the one and only science of mechanical engineering. Against the background of the developments in twentieth century technology it is at this moment in time more realistic to view MMS as one of several disciplines that play a role in mechanical engineering. However, MMS is different from the other disciplines that contribute to mechanical engineering in the sense that it owes its identity to a class of machines and mechanisms that dominated mechanical engineering in the nineteenth century. These machines and their descendents are still very important and MMS is flourishing. Within MMS the geometrical and kinematical aspects of machinery are still central, but as far as research is concerned the other theories that we find in MMS surrounding its kinematical core reflect twentieth century developments in mathematics, mechanics, computer science and other disciplines. In the nineteenth century the emphasis in kinematics had been on planar mechanisms. In the twentieth century a considerable interest developed in spherical and spatial mechanisms. As for methodology until after World War II graphical methods prevailed. Only with the rise of the information age and the introduction of electronic computers graphical methods were replaced by analytical methods. Nineteenth century geometry in its analytical form in combination with the power of modern computers offered a wealth of new possibilities for engineers dealing with the design of mechanisms.

IFToMM and Its Permanent Commission for HMMS In the nineteenth century books started to appear about kinematics and at universities chairs were introduced for ‘descriptive geometry and kinematics’. For some time Trajan Rittershaus even held in Dresden a chair for ‘pure and applied kinematics’. Moreover, in the first mathematical review journal, Jahrbuch für die Fortschritte der Mathematik, during its entire existence until World War II, a special subsection, first of mechanics and later of geometry, was devoted to kinematics. The institutionalization of kinematics never went further than this. Yet in the 1960s The International Federation for the Theory of Machines and Mechanisms (IFToMM), was founded. In IFToMM kinematics played initially a central role. It published a journal, the Journal of Mechanisms, which was very much oriented towards kinematics.

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It is remarkable that the foundation of IFToMM in 1969 was prepared in the years of the Cold War when the rivalry and competition between the two superpowers, the United States and the Soviet Union, was huge. IFToMM was founded by scientists from both sides working in mechanical engineering. In the 1960s the Russian Academician Ivan I. Artobolevskii organized a series of All-Union Conferences on contemporary problems in the theory of machines and mechanisms. In the same period the Americans in cooperation with the Europeans developed similar initiatives. In the Cold War engineers on both sides felt they could profit very much from each other. That is how IFToMM was born in 1969. On the institutional level the organization represents the modern version of the views of Reuleaux and like-minded other nineteenth century engineers (Fig. 6). The history of MMS is part of the history of science and technology. The word technology was coined by the German Johann Beckmann (1739–1811). He used it for a description and classification of all the existing crafts and methods of manufacture. The 1971 edition of Webster’s Third International Dictionary says that technology is “The science of the application of knowledge to practical purposes”. Definitions and distinctions are useful. However, it is difficult to draw a sharp border line between practical problems and non-practical problems. Basically a practical problem is a problem that requires some action outside of the study or the laboratory. In this context it makes sense to distinguish knowledge-how from knowledge-that. Knowledge-how is related to functionality; it concerns what should be done to reach some goal. We know how to get somewhere, how to do something, sometimes without even knowing why the method works. That is knowledge-how. Technology is or concerns always knowledge-how. Knowledge-that is related to truth; we know that something is the case, nothing more, nothing less. It may be completely useless.

Fig. 6  Bronze plaque in Zakopane (Poland) commemorating 40 years of IFToMM

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Pure science is knowledge-that. It is the multidisciplinary character of MMS in combination with the fact that it encompasses both knowledge-that and knowledgehow, which has led to a situation in which the history of MMS is not often studied in its own right. Obviously historians of science are interested in the history of machines, but only in so far as it concerns mathematics, physics or one of the other sciences. On the other hand, historians of technology tend to concentrate on the actual machines and their social and cultural impact; their focus is usually not MMS in its own right. That is where IFToMM’s Permanent Commission for HMMS is filling a gap. The activities of the commission cover all aspects of the history of machines and mechanisms and the theories dealing with them and cooperates with the IFTOMM Permanent Commission for Standardization of Terminology [5] concerning technical terms. The term Mechanism and Machine Science (MMS) has been adopted within the IFToMM Community since the year 2000 after a long discussion [6] with the aim to give a better identification of the enlarged technical content and it expresses a broader view of the knowledge and practice that IFToMM deals with [7]. The notion MMS replaced the notion Theory of Machines and Mechanisms that had been used since the founding of the Federation.

Activities of the Commission: Symposia For the activities of the Permanent Commission (PC) for HMMS until 2004 we refer to [8]. The PC for HMMS was established in 1973 because of the strong support from the first IFToMM President Ivan I. Artobolevskii and the enthusiasm of the first PC chairman, the late Jack Phillips from Australia. Between 1973 and the following years until 1997 the PC was chaired by Jack Phillips (1973–1981), Elisabeth Filemon from Hungary (1982–1989) and Teun Koetsier from the Netherlands (1990–1997). When Marco Ceccarelli from Italy took over the chair in 1998 (he held it until 2004) it was decided at the beginning of the new millennium to make also a new start in order to turn the PC for HMMS into a body functioning more satisfactorily. Marco Ceccarelli had the idea to organize HMMS symposia between the regular IFToMM World Congresses, i.e., every 4 years. In 2000 he organized at his home university in Cassino the first International Symposium on HMMS (HMM 2000) [9]. Four years later and again in Cassino there was the second International Symposium on HMMS (HMM 2004) [10]. The succeeding chairmen, Hong-Sen Yan from China-Taipei (2004–2007) and Hanfried Kerle from Germany (2007-present), followed Ceccarelli´s initiative for the sake of a better international cooperation of the PC members. So the third International Symposium on HMMS (HMM 2008) [11] took place at the National Cheng Kung University in Tainan (China-Taipei) preceded by an International Workshop on Digital Museums of Antique Mechanism Teaching Models chaired by Hong-Sen Yan. The workshop idea also goes back to Marco Ceccarelli who introduced workshop meetings of the PC HMMS community as a preparatory stage of a forthcoming

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symposium on HMMS. More information about the PC HMMS is given on the webpage http://www.webuser.unicas.it/weblarm/IFTOMMpcHISTORY/index.htm.

Book Series on HMMS and Workshops Springer Co. is publishing a series of books on HMMS. The series consists at present of eight volumes with three volumes in print. The series started in 2007 with [12]. More information is given on the webpage http://www.springer.com/ series/7481. The first workshop was held in Admont (Austria) from October 20–26 in 2002 (Fig. 7). On October 6–8, 2004, the second workshop was held in Dresden (Germany). Participants were (see Fig. 8 from left to right) Prof. Karl-Heinz Modler (Germany), Prof. Marco Ceccarelli (Italy), Prof. Kurt Luck (Germany), Prof. Alexandar Golovin (Russia), Prof. Hong-Sen Yan (China-Taipei), Prof. Francis Moon (USA), Prof. Teun Koetsier (The Netherlands), Prof. Carlos Lopez-Cajun (Mexico), Prof. Rudolf Neumann (Germany), Dr. Klaus Mauersberger (Germany), Prof. Burkhard Corves (Germany), Dr. Hanfried Kerle (Germany); not in photo: Prof. Baichun Zhang (China Beijing), Dr. Peter Plabmeyer (Germany). On May 17–19, 2005, the next workshop was held in Moscow (Russian Republic) at the Bauman State Technical University (BMSTU). Participants were (see Fig. 9) first line: Prof. Valentin Tabarin (Russia), Prof. Alexander Golovin (Russia), Acad. Prof. Konstantin Frolov (Russia), Prof. Tatyana Nevenchanaya (Russia),

Fig.  7  Participants in the first workshop of the PC HMMS in Admont (Austria). From left to right: Atsuo Takanishi (Japan), Teun Koetsier (The Netherlands), Marco Ceccarelli (Italy), Ignacio Cuadrado (Spain), Hanfried Kerle (Germany), Austrian attendee

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Fig. 8  Participants at the 2004 Dresden workshop on HMM

Fig. 9  Participants at 2005 Moscow workshop on HMMS

Prof. Vera Chinenova (Russia), Prof. Irina Tiulina (Russia); second line: Prof. Yuri Ermakov (Russia), Prof. Krystof Mianovski (Poland), Prof. Teun Koetsier (The Netherlands), Prof. Marco Ceccarelli (Italy), Prof. Olga Egorova (Russia), Prof. Baichun Zhang (China-Beijing), Miss. Nataly Maksimenko (Russia), Prof. Iosif Vulfson (Russia); third line: Prof. Vladimir Krukov (Russia), Prof. Boris Lushnikov (Russia), Prof. Manfred Husty (Austria), Miss. Ana-Marya Yeroshenko (Russia), (hidden), Dr. Klaus Mauersberger (Germany), Dr. Hanfried Kerle (Germany);

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Fig. 10  Participants at 2006 workshop at Cornell University

fourth line Prof. Hong-Sen Yan (China, Taipei), Prof. Francis Moon (USA), Mrs. Elisabeth Moon (USA), Prof. Rudolf Neumann (Germany); fifth line: BMSTU student (Russia), Mr. Nikolay Barnashov (Russia); sixth line: Miss. Dina Mkrchan (Russia). Participants not in the photo: Prof. Carlos Lopez-Cajun (Mexico) and Prof. Sergey Jatsun (Russia). On September 8–10, 2006, the fifth workshop was held at Cornell University in Ithaca, NY (U.S.A.), organized by Francis C. Moon. Participants were (see Fig. 10 from left to right): Mr. Kuo-Hung Hsiao (China-Taipei), Prof. Marco Ceccarelli (Italy), Prof. Paolo de Castro (Portugal), Prof. Hsing-Hui Huang (China Taipei), Prof. Teun Koetsier (The Netherlands), Prof. Agamenon Oliveira (Brazil), Prof. Burkhard Corves (Germany), Prof. Hong-Sen Yan (China-Taipei), Dr. Hanfried Kerle (Germany), Prof. Olga Egorova (Russia), Prof. Jörg Wauer (Germany), Prof. Hod Lipson (USA), Prof. Jian Dai (UK), Prof. Alexander Golovin (Russia), Prof. Francis Moon (USA); not in photo: Dr. David Corson (USA), Prof. Srifhar Kota (USA), Prof. Daina Taimana (USA), Mr. John Saylor (USA). The sixth Workshop on HMMS was held at the Indian Institute of Science (IISC) in Bangalore (India) in conjunction with NaCOMM 2007, the National Conference on Machines and Mechanisms of the Indian member organization. Twelve papers on HMMS were presented. The Workshop had been organized by Prof. Ashitava Ghosal from IISC. For his successful organization Prof. Goshal was given the PC Service Award 2007 from Prof. Marco Ceccarelli (President of IFToMM) and Prof. Hong-Sen Yan (past PC for History chairman). Some of the participants of the

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Fig. 11  Participants of 2007 workshop in Bangalore

Fig. 12  Participants of the PC HMMS meeting in Tainan. front row (from left to right): Marco Ceccarelli (Italy, President IFToMM), Hong-Sen Yan (China, Taipei), Hanfried Kerle (Germany, PC Chairman, Teun Koetsier (The Netherlands); Middle row (left to right): Baichun Zhang (China, Beijing), Jian Dai (UK), Francis Moon (USA), Olga Egorova (Russia); Last row: Torsten Brix (Germany), Tsung-Yi Lin (China, Taipei), Carlos Lopez-Cajun (Mexico, Secretary-General IFToMM), Manfred Husty (Austria)

Workshop were (Fig.  11 from left to right): Prof. Manfred Husty (Austria), Prof. Marco Ceccarelli (Italy), Prof. Shekar R. Narvekar (India), Prof. Teun Koetsier (The Netherlands), Prof. Jammi S. Rao (India), Prof. Francis Moon (USA), Prof. Hong-Sen Yan (China, Taipei), Prof. Baichun Zhang (China-Beijing). There was a HMMS workshop at the National Cheng Kung University in Tainan (China-Taipei) in 2008, in conjunction with the third International Symposium on HMMS, Fig. 12.

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References 1. Gregory, C.: A Farewell to Alms, a Brief Economic History of the World. Princeton University Press, USA (2007) 2. Moon, F.C.: Franz reuleaux; contributions to 19th century kinematics and theory of machines. Trans. ASME Appl. Mech. Rev. 56(2), 261–285 (2003) 3. Moon, F.C.: The Machines of Leonardo Da Vinci and Franz Reuleaux: Kinematics of Machines from the Renaissance to the 20th Century. Kluwer, Dordrecht (2007) 4. Kennedy, A.B.W. (ed.): The Kinematics of Machinery, Outlines of a Theory of Machines by Franz Reuleaux, with a New Introduction by Eugene S. Ferguson. Dover, New York (1963) 5. IFToMM: IFToMM commission a, standard for terminology. Mech. Mach. Theor. 26(5), 526 (1991) 6. Ceccarelli, M.: On the meaning of TMM over time. Bull. IFToMM Newsl. 8(1) (1999) 7. Ceccarelli, M. Evolution of TMM (Theory of Machines and Mechanisms) to MMS (Machine and Mechanism Science): an illustration survey. In: Proceeding 11th IFToMM World Congress in Mechanism and Machine Science, Tianjin, pp. 13–24, 18–21 Aug 2003 (2003) 8. Ceccarelli, M., Koetsier, T.: On the IFToMM permanent commission for history of MMS. In: Ceccarelli, M. (ed.) Proceeding HMM 2004. Kluwer Academic, Dordrecht (2004) 9. Ceccarelli, M. (ed.): Proceeding HMM 2000. Kluwer Academic, Dordrecht (2000) 10. Ceccarelli, M. (ed.): Proceeding HMM 2004. Kluwer Academic, Dordrecht (2004) 11. Ceccarelli, M., Yan, H.-S. (eds.): HMM 2008. Springer, Dordrecht (2009) 12. Ceccarelli, M. (ed.): Distinguished Figures in Mechanism and Machine Science – Their Contributions and Legacies, Part 1. Springer (2007) 13. Rupert, H.A.: Early modern technology, to 1600. In: Kranzberg, M., Pursell, C. (eds.) Technology in Western Civilization, Vol. I: The Emergence of Modern Industrial Society, pp. 79–103. Oxford University Press, London (1967)

On the Development of Terminology and an Electronic Dictionary for Mechanism and Machine Science A.J. Klein Breteler

Abstract  This chapter describes the work of PC Standards and Terminology, starting with the recording of the relevant terminology. With the development of the personal computer and the internet, attention moved from a printed version to an electronic version of the dictionary. This required working methods to be adapted and the development of software to create the intended webpage. The chapter describes the principal problems, discussions and decisions in the process which eventually resulted in the current version of the electronic dictionary.

History of PC Standards and Terminology The very first official meeting of the Commission for the “Standardization of Terminology” was held on 18 September 1971 during the third World Congress on the Theory of Machines and Mechanisms in Kupari, Yugoslavia. There were five participants: Professors Bazjanac (Yugoslavia), Bianchi (Italy), Bögelsack (GDR), Davies (United Kingdom, chairman) and Keller (Federal Republic of Germany). In accordance with the Constitution & By-Laws of IFToMM, the Commission’s objective was, from the very outset, to establish a specific and unitary terminology for MMS. Previously, several national and international groups had succeeded in compiling dictionaries and glossaries in this field. Some related publications are listed in the reference section as examples: The first [1] lists 90 terms in Russian, English, French and German, but these are defined in the Russian language only. A previous academic bulletin had been published in 1938. The German glossary [2]

A.J.K. Breteler (*) Faculty OCP/Mechanical Engineering, University of Technology Delft, Mekelweg 2, Delft 2628 CD, The Netherlands e-mail: [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_7, © Springer Science+Business Media B.V. 2011

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contains 221 terms and definitions illustrated with sketches and drawings. The dictionary [3] includes 610 terms in German, English, French, Russian and Bulgarian without definitions. Preliminary lists of terms were submitted by United Kingdom and GDR during the first meeting, and a provisional programme with responsibilities and a set of rules was drawn up (see next chapter for more details). This was the basis for the further development of terminology. Since then, Commission working meetings have been organised in various countries, with rare exceptions, every 2 years. The chairmen of the Commission have been D. Muster (1972/1976), G. Bögelsack (1976/1986), J. Prentis (1986/1990), T. Leinonen (1990/1998), T. Ionescu (1998/2005), A. J. Klein Breteler (since 2006). A more detailed overview of the work done by the Commission prior to 1996 is presented by Bögelsack [4]. The publishing format considered at that time was obviously just printed paper, but discussions on new publishing media (CD-ROM, Internet) began in 1998 during the meeting in Brno. The results can be found in the chapters that follow.

Statements for Developing Terminology The terminology includes a set of terms and their definitions. Working on the principle that a good definition should distinguish by identifying and identify by distinguishing, the Commission reached an agreement on the following rules to be observed in the methodology of defining: –– In each context, it must be possible to replace the term to be defined (definiendum) by the definition (definiens); –– A definition may neither contain nor cause any contradiction of logic; –– The term to be defined may not appear in the definition either openly or implicitly (circular definition); –– The predicate of a definition should not be negative; –– Definiendum and definiens must be identical in extent; –– A term should be neither overdefined (more characteristics in the definition than in the term) nor underdefined. Some further guidelines were later proposed by J. M. Prentis in 1989: –– Terms should be elegantly defined in the simplest possible language; –– Definitions should be concise; –– Terms should not be needlessly multiplied, e.g., (common adjective) + (old term) = (new term); –– Terms should not be included (or, even worse, invented) simply to provide a counter-point to other terms; –– A term that is easier to understand than the definition should be deleted unless a simpler definition can be found; –– When in doubt, leave it out!

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Structure and Layout of the Terminology The set of terms must be ordered in a certain way. During the early discussions, it was agreed to make an ordering/classification into five chapters that reflect the core topics of MMS: Structure of MMS, Kinematics, Dynamics, Machine Control and Measurements, Robotics, and a chapter with general terms. A sub-commission for each chapter developed the terminology in the English language. Once agreement in the whole Commission had been reached, the terms were translated into the other three languages. The resulting structure and layout, which was adopted in 1991, appears in the figure below: the printed version contains four parallel columns spread across two adjacent pages [5].

Layout detail: when a term in a definition is referenced (has a definition elsewhere), that term is printed in italics. Any synonym for a term is placed in square brackets. Search facilities for the user are supported by providing an alphabetic index list of the terms in all four languages. A comment on this method of ordering: the ordering sequence of the terms is done “from the bottom up”, which means references are made to previous terms

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where possible. This enhances the readability of a chapter or sub-chapter and is certainly an advantage while the terminology is being developed. One drawback with this system of ordering, however, is that inserting a new term or deleting an existing term may lead to extensive renumbering of the terms in the next version. In 1991, digital word-processing facilities were still very limited. ASCII-based text files were produced by one of the members of the Commission (Prentiss). Nonstandard characters, such as ü or â, were indicated by special ASCII-codes for that purpose. Referenced terms were indicated by placing them in , to be replaced with the italics by the publisher. The Cyrillic text was prepared separately.

Statements for Developing an Electronic Dictionary After 1991, the personal computer and the internet rapidly became much more widely used as means of mass communication. This meant that there was demand for an electronic version of the IFToMM dictionary, either on CD or on a webpage. All references in such an electronic version would need to be links that could be clicked on. Discussions on the functionality of this software and the electronic dictionary ultimately led to a list of user demands and developer demands [7]. The tables below shows the ways in which an electronic version would be better than the printed version (+ means “present”, – means “not present”, j means “partly present”). User demands Select set of languages Search for a term alphabetically Display explanation of a term (text) Display graphical explanation (picture) Display reference (link) Display reference list (all links within one term) Display refereed list Export of information to other channels (print) Select content (chapter) Retrieve synonyms Advanced query options for search of a term Easy access to members of IFToMM community Take part in discussion forum on terms

Paper version

Electr. version

j + – – – – – – j + – j –

j + + – + + + + j + j + j

Developer demands Effective communication means (email) Effective working method (subcommissions, standard forms) Method fits working skills (text editor) Intermediate products (files), compatibility Processing of output (book, webpage, CD)

Paper version – j j j j

j + + + +

Electr. version

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A comment on the proposals for setting up an electronic dictionary: the best solution is probably the creation of a central database and a website with two pages: one for updates and maintenance, and one which allows access for all IFToMM users. This solution did not yet appear feasible, not only because of anticipated cost, but also because of the incompatibility with a printed version. The Commission agreed to continue with the present structure (chapters and subchapters) and a text file for each chapter, for which a sub-commission could be made responsible. Such a set of text files should be created for all four languages. However, in preparation for the electronic version, a standard text editor (Word97) and file layout (table with four columns) was adopted. Non-standard characters and Russian characters no longer caused problems because of the Unicode standard. To avoid compatibility problems with other word-processing programs, no use was made of any mark-up information such as italic text and the references were kept in . The existing ASCII files into Word files were converted by means of a simple “read-in” after some layout preferences had been inputted manually. The reverse procedure, conversion to a pure ASCII file, can be done without the loss of any core information, if this should ever be required in the future. Using the working method with Word files, several new chapters were developed with the more specialised terms of sub-domains (dynamics supplement, rotor dynamics and measurement, vibrations and nonlinear oscillations, stability, biomechanics, gearing, mechatronics). With the extensions only available in English, a printed version was issued [6] showing the Word files with almost no adaptations by the publisher. The huge number of printed pages (over 500 pages, including the index sections) once more demonstrated the need for an electronic version.

Development of an Electronic Dictionary In response to the demands of users and developers, it was agreed that an electronic version should be similar to the printed book, but now with additional browsing by means of links in the alphabetic index section and between definitions. The Commission members preferred a four-column layout (with four languages), as used in the first printed edition across left and right page. Unfortunately, such a format does not match standard screen dimensions and an alternative idea was accepted of two languages appearing on the screen at one time. The electronic dictionary is thus actually a set of several bilingual dictionaries. Given that each of the four languages could be selected as “first” and “second”, 16 dictionaries were then required (including the combination of a language with itself, which appears then as a dictionary with just one column). One advantage of this approach is the possibility of expanding the dictionary to additional languages. With respect to

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manageability and maintenance, for n languages, n2 dictionary files are required. It is unlikely that a high number of languages can be managed, but in practice not every possible language combination is likely to be required. It was recognised that such a development must be supported by software that had to be designed from scratch. With the advice and practical help of a professional software developer, it was decided to use the software available in the Windows developers’ platform as far as possible. It was expected that the programming job would then be relatively small. XML files, which are standard for structured data, were chosen as the preferred file type for the dictionary files. The programming then focused on the process between the Word files and the XML files and the links to be assigned automatically. From the XML files, it was relatively easy to derive other products like PDF files (for printing) and HTML files (for websites). The software developed creates the dictionary in three stages (for more details, see [7]): Step 1: The data are collected from the individual Word files into one central database (Access). This action is necessary to allow the link search. Typically, the database has two tables: one for the definitions of the terms and one for the index lists. The tables can be inspected manually (sample part see figure below), although changes to the records are not meant to be carried out manually. In case of a modification of a Word file, the relevant language section in the database tables must be updated as a whole.

Step 2: XML files are created in which the links have been resolved. It was decided that one file for each language combination would be made and for each chapter, so there are n2 = 16 files per chapter. You can see a sample of an XML file in the

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figure below. The “links” can be recognised: it contains a reference to a file where the term number is present. It is possible to edit such an XML-file directly, although edits are not meant to be carried out in this way. The problems with automatic link resolving will be discussed in the next chapter.

Step 3: Conversion to HTML files (or other output to a different “channel”). Separately created “style sheets” determine the actual look of the result on the screen. A software tool that can perform the three steps has been written in Visual Basic. Due to the look of the user interface, it has been given the name “Transformation Panel”. The figure below shows an example of how step one can be performed for French and German.

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Having finished the software, two problems required much more time than was originally estimated: –– The inclusion of Russian language in the XML and HTML documents. This was solved completely within the software. –– The automatic link-resolving procedure. Several experiments with link search algorithms were proposed and tried out (more in next chapter). The first electronic version of the dictionary was completed in 2004 and consisted of (downloadable) compiled HTML files, to be run on the computer of the user. This version can be found in the following report [8].

Critical Problems The software also affected the role of the Word files and the way they were named. The Word files serve as input data for a computer program that has many automated functions, such as generating a table of contents (from the table headers) and matching the links (from the terms in ). A strict layout specification was required because almost any typing error would lead here to an undesired result.

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A second consequence was that the name of the Word files needed to be standardised. A language-independent name, containing the chapter number, was chosen for the files containing the definitions: 01.doc, 02.doc etc. This guarantees that the names can be extended for more chapters and languages. They are kept in a directory which contains the international country code (1,031 for German, 1,036 for French, 1,049 for Russian, 2,057 for English). Regarding the automatic link search, it was recognised that the index table in the database contains all instances of the terms. This list is therefore the preferred source for the search (the definitions tables contain just one instance and are more complicated to investigate because of the extra information on synonyms). The index file, in Word, must therefore be free of any typing errors. The text in the definitions files between the must also be error-free. The major problem with assigning links [7] is that the referenced term may contain a derived word, for instance a plural or a different case ending. Grammar rules are quite different in the four languages and it would seem impossible to integrate all these rules into a general search algorithm. However, using some form of smart algorithm, it is expected that only a limited number of unresolved links will remain. These links can be contained in an extra “missing links” file, alongside the index file, which can be created manually. This information will be used when the XML files are being created. A further strategy is that the links in the English files can be resolved first, giving the other languages access to the English search results (term number) for extended matching trials. The search algorithm finally used consists of the following match attempts, to be taken in the order shown here: • Full match of all characters (without case sensitivity), search in both the index table and the missing links table; • Full match except for the trailing character “s” (very effective for English plural nouns); • For non-English: fair match when comparing the links of the English term (the best term has the highest percentage of corresponding characters of all words to match); • Wild search with the facilities of the Access software (sometimes successful). The results of the search are reported to a file that must be inspected manually. In case of a missing or erroneous link, the referenced text must either be modified or added to the missing links file until all the links are complete. One point for discussion is the option of anticipating the search algorithm while the term is being defined. When proposing a term and its description, the editor should be aware of the procedure for search for links. It may then be possible to avoid the use of the missing links table in advance.

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Results and Conclusions When the first electronic dictionary was completed, a considerable amount of work was still underway: the translation of the Chaps. 7–12 into the other languages. During this process the “Transformation Panel” software was extended in terms of functionality for creating the webpages for a central website: –– Display the referenced links (with an open/close button); and –– Search for any text string in the whole (bi-lingual) dictionary. See the figure below for a screen dump comparable with the first figure; note that the links for term 2.2.2 have been opened.

It can be concluded that the project to create an electronic dictionary for MMSterminology has been successfully completed. Hopefully, the current version [9] will be useful for all members of the IFToMM community when reading or writing papers. It is definitely a major help for the IFToMM Commission itself to discuss improvements and the further development of terminology. Updates to the whole dictionary can be expected regularly.

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References 1. Levitskyi, N.I., et  al.: Teorija Mechanizmow – Terminologija. Isdatelstwo Nauka, Moskwa (1964) 2. VDI Richtlinie 2127: Getriebetechnische Grundlagen – Begriffsbestimmungen der Getriebe. VDI Verlag, Düsseldorf (1962) 3. Konstantinov, M.S., Artobolewskyi, I.I., Hartenberg, R.S. et  al.: Concise Terminological Dictionary on Kinematics and Dynamics of Machines. Sofija (1965) 4. Bögelsack, G.: Twenty – five years IFToMM commission a standardization of terminology – history, methodology, results and future work. Mech. Mach. Theor. 33(1/2), 1–5 (1998) 5. IFToMM Commission A: Terminology for the theory of machines and mechanisms. Mech. Mach. Theor. 26(5), 435–539 (1991) 6. IFToMM Commission A: Terminology for the mechanism and machine science. Mech. Mach. Theor. 38(7–10), 598–1111 (2003) 7. Klein Breteler, A.J.: On the development of an electronic dictionary for IFToMM. In: Proceedings of Scientific colloquium in Bardejov Spa, Slowakia, June 2005 8. Ionescu, T.G., Klein Breteler, A.J., Leinonen, T., Bögelsack, G.: On the progress of standardization of mechanism and machine science terminology. In: Proceedings of the 12th World Congress on MMS. Besancon , 18–21 June 2007 9. Websites of the online dictionary: www.iftomm.org, www.iftomm.3me.tudelft.nl

The Role of Mechanism Models for Motion Generation in Mechanical Engineering Hanfried Kerle, Burkhard Corves, Klaus Mauersberger, and Karl-Heinz Modler

Abstract  The paper gives a historical overview of the development of mechanism or kinematic models for motion generation in mechanical engineering. Models can serve for teaching purposes and also serve as small test rigs when investigating the running behaviour and estimating the running quality of a mechanism or machine. So the development of mechanisms and machines through the last centuries since Antiquity is also coupled to the development of design of virtual and physical mechanism models.

Introduction The oldest work about mechanical systems which we know is that of the great Greek Aristotle (384–322 B.C.). In his “Mechanical Problems” he mentions the “mechanical aids” or “elementary machines” of Antiquity, i.e., the lever, the wedge, the wheel and the pulley. The screw or the worm-wheel is not mentioned explicitly, but it must have been known in those time, latest at the time of Archimedes (287–212 B.C.) whom many technical historians take for having invented the screw [1]. Archimedes seems to have been the first who attached the mechanics of elementary machines to fundamental machine components or mechanisms by looking at the kinematics and statics of a lever and a screw [2]. The Romans thereafter learned and

H. Kerle (*) TU Braunschweig, Peterskamp 12, Braunschweig D-38108, Germany e-mail: [email protected] B. Corves RWTH Aachen, Aachen, Germany K. Mauersberger and K.-H. Modler TU Dresden, Dresden, Germany M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_8, © Springer Science+Business Media B.V. 2011

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adopted a lot from the Greeks, e.g., we owe the Roman Marcus Vitruvius Pollio (around 16 B.C.) the fact that a considerable part of Greek knowledge of machines and mechanisms could be preserved in his ten-volume work “De Architectura” [1, 3]. Unfortunately the figures that Vitruvius attached to his work have been lost and could only be interpreted and completed by following the text. Figures were rare in Antiquity and also during the Middle Ages the knowledge of machines was limited to very few people in a very restricted community. The change occurred in the period of the Renaissance between the fourteenth and seventeenth century when the interest in machines generally grew up with the needs of peers and sovereigns for architectonic purposes, military defences and hydraulic apparatus. The Renaissance of machines starts with a row of famous “artist engineers”, especially Italians. Filippo Brunelleschi (1377–1446) designed and used several new mechanisms. Also prominent in the first phase of the Renaissance of machines was Mariano di Jacopo – il Taccola (1382–1453) with his practical studies of machines and mechanisms. Francesco di Giorgio Martini (1439–1501) stands at the beginning of the second phase of the Renaissance of machines. He was a very gifted and creative designer of machines and wrote for example a treatise on pumps and their operations. The most known Italian artist engineer is a contemporary of Francesco di Giorgio, namely Leonardo da Vinci (1452–1519), because of his large and encyclopaedic collection of sketches and also three-dimensional drawings which have fortunately been preserved for succeeding engineers and architects. But we must point out the fact that in the field of machine design Leonardo profited considerably from the works and ideas of Brunelleschi, Mariano di Jacopo and Francesco di Giorgio [3]. At that time the majority of presented engineering models were “virtual models” represented by sketches or drawings. It took time and the appropriate technology of printing till the end of the sixteenth century to present illustrated books. Following the technical historian Eugene S. Ferguson (1916–2004), two different traditions of such “machine books” emerged [4]: The first tradition aimed at suggesting new and novel ideas to anyone who could “read” the illustrations. Books belonging to this group were also called “theatres of machines” [5]. The first “theatre of machines” was that of the French Jacques Besson (»1540–1596), published in 1578 in Lyon and titled “Théatre des Instruments mathématiques et mécaniques”. The book contained about 60 copperplates of machine drafts (machine models) and mathematical instruments. The most known “theatre of machines” is that of the Italian Agostino Ramelli (»1530–1590) which set the standard for more than 100 years. The title ran “Le Diverse et Artificiose Machine” and was published in 1588 in Paris, Fig. 1. The first two books that belonged to the second tradition of transmitting technical information in detail through illustrations were those of Vanoccio Biringuccio (1480–1538) from Siena (Italy) and Georg Agricola (1490–1555) from Glauchau, Saxony (Germany). Their books dealt with mining and refining of metals and minerals. Biringuccio’s book titled “De la pirotechnia” was published the first time in 1540 in Venice, whereas Agricola’s book “De re metallica” with over 250 wood engravings appeared in 1556 in Basle, 1 year after his death.

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Fig.  1  Cover page of Ramelli’s “theatre of machines” (German translation) and one of his machine models, a water-driven water pump

A last artist engineer must be mentioned who closes the cycle of Renaissance “theatres of machines” and at the same time opened the window to a new view of machines: Jacob Leupold (1674–1727) from Leipzig (Germany) published a tenvolume work between 1724 and 1739 titled “Theatrum Machinarum Generale”. Leupold dismantled a machine analytically into its single parts, described their special functions in the machine and also added critical remarks of design and efficiency. Not every machine which Leupold described was his own invention, but he collected the known “machine models” at his time and thus presented the state of the art in his books. By dismantling a machine into its parts, Leupold created lists and drawings of the basic mechanical elements of a machine, Fig. 2. In the seventeenth century models were used more and more to inform various people of the nature of available machines and devices for carrying out a wide variety of technical tasks. At the end of the seventeenth century the construction and the display of models were even standardized to some extent. For example, soon after its establishment in 1666 the Académie des Sciences in Paris employed modelmakers to develop a cabinet of models of “various widely used machines”, Fig.  3. Members of the Académie as well as non-members were encouraged to record their inventions and to contribute to the basic cabinet and thus to raise the importance of the science of mechanics in mechanical engineering.

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Fig. 2  Water wheel and screw mechanisms by Leupold

Fig. 3  Copperplate of the Model Cabinet in the Académie des Sciences in Paris in 1666

Mechanisms and Mechanism Models A very important step concerning “elementary mechanisms” being basic elements of a machine came from France. In 1794 at the end of the French Revolution the École Polytechnique was founded in Paris. Gaspard Monge (1746–1818) taught kinematics as part of his subject “Géometrie descriptive”. His scholars

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Fig. 4  Part of the mechanism catalogue by Lanz and Betancourt

Jean N. P. Hachette (1769–1834), José M. Lanz (1764–1839) and A(u)gustin de Betancourt (1758–1824) became protagonists of a “kinematic machine science”. They classified all relevant mechanisms of their time concerning the type of elements, type of generated motion (“mechanical movement”) and direction of motion (input/ output link). These mechanisms were sorted as elements of a matrix that can be regarded from a today´s point of view as a “virtual mechanism model catalogue”, Fig. 4. The catalogue was published in 1808 [6]. By the way, a similar catalogue of so-called “kinematic models” was presented 60 years later in 1868 by the New York patent attorney Henry T. Brown, Fig. 5 [7]. Based on this catalogue the American engineer William M. Clark built in the early 1900s around 200 so-called “working models”. Today 120 of these mechanism models are housed at the Museum of Science in Boston, MA (USA) [8]. In the following part of this chapter we will try to find answers to the following questions: • Is there a difference between original mechanisms and model mechanisms? If yes, which criteria are important and must be respected for the design and construction of mechanism models? • Which basic types of mechanism models do exist? • Is it still worthwhile to deal with or even build mechanism models in a time reigned over by the computer with efficient mathematical and graphical tools? Hermann Alt (1889–1954), professor of kinematics in Dresden and Berlin, published an interesting paper in 1953 about mechanism models [9]. Among other things he wrote (translated from German into English):

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Fig. 5  Part of Brown’s catalogue of kinematic models

The use of mechanism models as educational aids in technical colleges and other technical training schools, as well as in the designing offices and other departments of the mechanical and precision engineering industries, has long been realized as an important medium. It should clearly be noted that in the field of mechanisms there are technical problems which are entirely different from those encountered in other branches of engineering design. This applies particularly to mechanisms with so-called periodic motions, for instance cam and lever mechanisms, where the sequence of movements cannot be read in most cases immediately from the blueprints. If a mechanism has to be developed, the designer must be able to visualize the mechanism as a movable part of a machine. It is particularly valuable for students and engineers to be able to watch the mechanisms in motion and possibly to set them in motion themselves in order to get a feeling for the sequence of movements.

So with a mechanism model the student or engineer gets a feeling of the running quality or the reaction of the output to the input by moving the input link manually. After having designed a mechanism the designer always asks himself “Will it work?” or “Will the joints allow sufficient motion over the entire ranges?” or “To what extent

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will friction and wear in the joints influence the service life of the whole mechanism?” For planar mechanisms the checks can be carried out more easily than for spatial mechanisms, because analytical methods with spatial mechanisms are long and involved [10]. So the best way to find proper and reliable answers to the questions put in quotation marks just before is to build a model, not only for the sake of the designer himself, but also to “sell” his design or invention to others in his organization or professional community. Thus, mechanism models may serve as load-bearing test rigs for experimental investigations and the results gained through experiments can be calculated back to the behaviour of the corresponding original mechanisms on the base of model laws of similarity mechanics [11]. A rough classification of mechanism models can be established as follows: • Virtual models (sketches and drawings) • Real physical models (models for didactic and experimental purposes) • Artificial physical models (rapid prototyping models) The artificial models are products of modern times. The manufacturing process – sometimes also called three-dimensional printing – requires a three-dimensional CAD model and a special machine tool for processing powder or other synthetic material.

Some Historical Remarks on Mechanism Models Christopher Polhem (1661–1751), later also called the “Swedish Daedalus”, was most probably the first technician and technical teacher who used real physical mechanism models to explain the basic elements of a machine and how these elements worked in a machine generating motion(s). His “Laboratorium mechanicum” established around 1700 to promote the study of machines became after his death the core of the collection in the Royal Chamber of Models in Stockholm, founded in 1756. Of particular interest was a series of wooden mechanism models called Polhem’s “mechanical alphabet” which is still today preserved at the Technical Museum of Stockholm, Fig. 6. The continuous growth of mechanism model collections and cabinets went along with an upcoming industrialization period in the eighteenth and nineteenth century all over the world. In that time the demand for thermal and kinetic energy increased more and more and the invention of the steam engine of James Watt (1736–1819) and other engineer colleagues not only radically altered the energy situation, but also created a whole new family of mechanisms (linkages) [12]. Again, the efficiency of mechanism inventions could be proven and demonstrated to factory owners and engineers through models in the best way. One of the famous kinematicians in that time was Ferdinand Redtenbacher (1809–1863) from Steyr (Austria). He was eager to set into practice the teaching ideas developed at the École Polytechnique in Paris. In 1841 he became professor within the Mechanical Engineering Department of the Polytechnic School in

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Fig. 6  Part of Polhem’s “mechanical alphabet”

Karlsruhe (Germany). He is seen today as the founder of the teaching of scientific mechanical engineering that is a symbiosis between mathematics, physics and practical engineering applications, the latter based on an extensive model collection being part of the study of engineering at the Polytechnic School, Fig. 7. His models were already manufactured following the model laws mentioned before concerning size and materials [13]. In 1857 Redtenbacher published a book and catalogue [14] that described 60 models of his collection, with a supplement of 20 models in 1861. A detailed survey over Redtenbacher and his lifework is given in [15]. Johann Andreas Schubert (1808–1870) was a contemporary of Redtenbacher in Germany. He also followed the line of teaching kinematics that was developed at the École Polytechnique in Paris. When teaching machinery to his students at the Royal Polytechnic in Dresden (Saxony), Schubert used models made of (cedar)

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Fig. 7  Original Redtenbacher mechanism models from Karlsruhe

Fig. 8  Five of nine preserved cedar wood Schubert mechanism models

wood, brass and iron. Schubert laid the foundation of the large model collection at the Technical University of Dresden today. But from Schubert’s original models only nine cedar wood models could be preserved, Fig. 8 [16]. Franz Reuleaux (1829–1905) from Eschweiler near Aachen in Germany was Redtenbacher´s most famous scholar in kinematics. Reuleaux is regarded as the founder of modern kinematics [17]. He started to establish design principles for mechanisms and machines and invented the “kinematic chain” – sometimes also called “kinematic train” – forming the base for mechanisms or “elementary machines”, i.e., the screw-chain, the wheel-chain, the crank-chain, the cam-chain, the ratchet-chain and the pulley-chain [18]. Within this frame Reuleaux developed

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Fig. 9  Five of around 800 Reuleaux mechanism models from Berlin

methods to codify, analyze and synthesize mechanisms so that engineers could approach machine design in a rational way. Moreover, between 1870 and 1876, he compiled a collection of over 800 models at the Polytechnic School in BerlinCharlottenburg, where he was professor for machine design, Fig. 9. During World War II the Berlin collection was widely destroyed. Incidentally, the last curator of the complete model collection was Hermann Alt, already mentioned before. The Reuleaux models were also built for sale to technical teaching institutions and industrial companies worldwide. The largest collection of Reuleaux models is that at Cornell University in Ithaca, NY (USA) with 219 items. Nowadays Cornell University has established a virtual museum on the web presenting all its Reuleaux models, cf. the webpage http://kmoddl/library/cornell.edu. A very interesting historical overview of these models is given by Francis C. Moon, the curator of the Reuleaux collection at Cornell University [19]. Moreover, the reader who is interested in kinematics finds a lot of old books of kinematics on the webpage mentioned and can download them simply and immediately. A similar, but wider approach has been done in Germany since 2005 by three relevant institutes at different universities: Ilmenau, Aachen and Dresden, cf. the webpage http://www.dmg-lib.org/dmglib/main/portal.jsp [20]. This project was financially supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) and is now continued by the institutes themselves. The focus is on the collection, selection, and preservation of knowledge in the mechanical

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Fig. 10  Webpage with mechanism models of the German research activity “DMG-Lib”

engineering field of mechanical motion systems and therefore based on internet tools forming a central information memory. This memory includes literature, kinematic models and model descriptions, interactive animations of models, and biographies of persons who have contributed to the knowledge of kinematics, Fig. 10.

The Influence of IFToMM Activities on the Dissemination of Knowledge of Mechanism Models The IFToMM Permanent Commission (PC) for History of Mechanism and Machine Science (HMMS) was founded in 1973 with the late Jack Phillips (1923–2009) from Sydney (Australia) as its first chairman. The activities of this PC are planned and executed in order to promote the republishing of classical works of reference, to promote the collection and circulation of material and information in the field of HMMS. When Marco Ceccarelli from the University of Cassino (Italy) became chairman of the PC HMMS in 1998, he had the idea to organize meetings of its members between the regular IFToMM World Congresses every 4 years. In 2000 he started

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a new initiative at his home university and called for papers to be presented at the first International Symposium on History of Machines and Mechanisms (HMM 2000). Four years later and again in Cassino on the occasion of the second International Symposium on History of Machines and Mechanisms (HMM 2004) Francis C. Moon talked about the already mentioned large Reuleaux model collection at Cornell University. Again 4  years later the interest in ancient kinematic models within the HMMS community had increased remarkably. Especially Asian country members became aware of almost forgotten model collections. So the third International Symposium on History of Machines and Mechanisms (HMM 2008) at the National Cheng Kung University (NCKU) in Tainan (Taiwan) was preceded by an International Workshop on Digital Museums of Antique Mechanism Teaching Models chaired by Hong-Sen Yan, the director of the NCKU museum. Moreover, there were more papers than ever before about kinematic models presented at the symposium [21]. We can take from these activities the following results: • There is now a complete overview of more than 600 Russian mechanism models at Bauman University in Moscow thanks to the work of Alexander Golovin and Valentin Tarabarin [22]. The collection also includes new, modern models which are intensively used for teaching students. Moreover, it seems important to us to point to the large encyclopaedic collection of virtual models published in five volumes – some volumes even existing of two parts – by the late Academician Ivan I. Artobolevsky (1905–1977), one of the founders of IFToMM [23]. • Kyoto University in Japan preserves a total of 60 machine mechanism models in the typical Reuleaux style. At least 21 of these models were imported from Germany in 1903. The rest of the models were manufactured by the Japanese company Shimadzu Corporation in 1913. The knowledge of this historical collection essentially goes back to the investigations of Sohei Shiroshita from Kyoto University [24]. • Shimadzu Corporation also manufactured the larger part of totally 119 machine mechanism models that were housed at three different universities for mechanical engineering in Taiwan, i.e., the National Taipei University of Technology (NTUT), the National Cheng Kung University (NCKU) in Tainan and the National Taiwan University (NTU) in Taipei. Under the leadership of Hong-Sen Yan a museum at NCKU was founded in 2006 to collect, exhibit and investigate all Taiwan´s antique mechanism models, cf. also the webpage http://www. acmcf.org.tw [25]. Moreover in the meantime, Hong-Sen Yan and two of his co-workers published a book showing all the 119 models in a very attractive way and gave competent explanations of their origin, function and design [26]. • The Faculdade de Engenharia da Universidade do Porto (FEUP) in Portugal owns a major collection of 113 items of Reuleaux models. Most of them were bought from the Gustav Voigt Mechanische Werkstatt in Berlin by Joaquim de Azevedo Albuquerque (1839–1912) who founded the Gabinete de Cinemática da Academia Polytechnica do Porto when he was chair of the Rational Mechanics and Kinematics Department at this Polytechnic. Nowadays the models are part of the FEUP museum, and some of them are still used for the teaching of students [27].

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Conclusions Kinematics is the general base of machinery, for the generation of motions and the transmission of forces and torques. All those mechanical engineers engaged on the design and construction of machines must have a thorough appreciation of mechanisms. In former times the mechanical engineer had to develop his professional skills of how to imagine motions only from drawings or blueprints. So, mechanism models were a valuable and essential tool in the training of students, technicians and engineers. But still today models give us a feeling of how a machine works and of its running behaviour. Acknowledgments  The authors want to thank Prof. Marco Ceccarelli from the University of Cassino (Italy) for his kind support and scientific advice when preparing this paper.

References 1. Beck, T.: Beiträge zur Geschichte des Maschinenbaues. Julius Springer, Berlin (1899) 2. Ceccarelli, M.: Historical evolution of the classification of mechanisms. In: Ceccarelli, M. (ed.) Proceeding International Symposium on History of Machines and Mechanisms – Proceeding HMM 2004, pp. 285–302. Kluwer Academic, Dordrecht (2004) 3. Ceccarelli, M.: Renaissance of machines in Italy: From Brunelleschi to Galilei through Francesco di Giorgio and Leo- nardo. Mech. Mach. Theor. 43, 1530–1542 (2008) 4. Ferguson, E.S.: Engineering and the Mind´s Eye. The MIT Press, Cambridge (1992) 5. Hilz, H.: Theatrum Machinarum – Das technische Schaubuch der frühen Neuzeit. Deutsches Museum, München (2008) 6. Lanz, J.M., de Betancourt, A.: Essai sur la Composition des Machines. Paris (1808) 7. Brown, H.T.: Five Hundred and Seven Mechanical Move- ments. Brown, Coombs & Co, New York (1868) 8. Clark, W.M., Downward, V.: Mechanical Models: A Series of Working Models on the Art and Science of Mechanics. The Newark Museum, Newark (1930) 9. Alt, H.: Getriebemodelle. VDI-Tagungsheft, pp. 197–200. Deutscher Ingenieur, Düsseldorf (1953). Band 1 10. Torfason, L. E.: Kinematic Models of Spatial Mechanisms. ASME paper no. 70-Mech-74 (1970) 11. Kerle, H.: On the power transmission and running quality of micro-mechanisms. In: Ceccarelli, M. (ed.) Proceeding EUCOMES 08, pp. 377–385. Springer (2009) 12. Ferguson, E. S.: Kinematics of mechanisms from the time of Watt. The Museum of History and Technology, Washington, DC, pp. 185–230, paper no. 27 (1962) 13. Mende, M.: Technische Sammlungen und industrielle Entwick- lung, pp. 15–27. PrestelVerlag: Das k.k. National- fabriksproduktenkabinett, Technisches Museum Wien (Austria), München/New York (1995) 14. Redtenbacher, F.J.: Die Bewegungs-Mechanismen. Verlagsbuchhandlung F. Bassermann, Heidelberg (1857) 15. Wauer, J., Mauersberger, K., Moon, F.C.: Ferdinand Jakob Redtenbacher (1809–1863). In: Ceccarelli, M. (ed.) Distinguished Figures in Mechanism and Machine Science – Their Contributions and Legacies, Part 2. History of Mechanism and Machine Science, vol. 7, pp. 217–245. Springer, Dordrecht (2010) 16. Mauersberger, K.: Die Getriebemodellsammlung der Technischen Universität Dresden. Wiss. Zeitschrift der TU Dresden 46(3), 103–106 (1997)

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17. Moon, F. C.: The Machines of Leonardo da Vinci and Franz Reuleaux – Kinematics of Machines from the Renaissance to the 20th Century. History of Mechanism and Machine Science, vol. 2 (series editor: Ceccarelli, M.). Springer, Dordrecht Washington, DC (2007) 18. Reuleaux, F.: The Kinematics of Machinery – Outlines of a Theory of Machines. Macmillan, London (1876) 19. Moon, F.C.: Franz Reuleaux: contributions to 19th century Kinematics and theory of machines. Trans. ASME: Appl. Mech. Rev. 56(2), 261–285 (2003) 20. Brix, T., Döring, U., Corves, B., Modler, K.-H.: DMG-Lib: the digital mechanism and gear library project. In: Proceeding 12th IFToMM World Congress on Mechanism and Machine Science, Besançon, June (2007) 21. Yan, H.-S., Ceccarelli, M. (eds.): International Symposium on Hi-story of Machines and Mechanisms. In: Proceeding HMM 2008. History of Mechanism and Machine Science, vol. 4 (series editor: Ceccarelli, M.). Springer (2009) 22. Golovin, A.; Tarabarin, V.: Russian Models from the Mechanisms Collection of Bauman University. History of Mechanism and Machine Science, vol. 5 (series editor: Ceccarelli, M.). Springer (2008) 23. Artobolevsky, I.I.: Mechanisms in Modern Engineering Design – A Handbook for Engineers, Designers and Inventors, vol. I–V. Mir, Moscow (1975–1980) 24. Shiroshita, S.: Technology transfer of educational machine mechanism models. International Symposium on History of Machines and Mechanisms. In: Proceeding HMM 2008. History of Mechanism and Machine Science, vol. 4, pp. 365–375 (series ed.: Ceccarelli, M.). Springer (2009) 25. Yan, H.-S., Huang, H.-H., Kuo, C.-H.: Historic mechanism teaching models in Taiwan. In: Proceeding 12th IFToMM World Congress on Mechanism and Machine Science, Besançon (France), June (2007) 26. Yan, H.S., Huang, H.H., Kuo, C.H.: Antique Mechanism Models in Taiwan. National Cheng Kung University Museum, Tainan (2008) 27. Tavares, J.M.R.S., Guedes, M.V., de Castro, P.M.S. T.: The Collection of Reuleaux Models of the Faculdade de Engenharia da Universidade do Porto, Portugal: Brief Historical Note and Current Status. In: Proceeding Workshop on the History of Mechanism and Machine Science, Ithaca, Sept 2006 (2006)

Development of Computational Kinematics Within the IFToMM Community Doina Pisla and Manfred L. Husty

Abstract  With the advent of symbolic computation and the development of new methods and algorithms in numerical mathematics the classical field of kinematics has undergone a renaissance. But it was not only the new methods that caused this renaissance. Where classical kinematics studied mainly mechanisms and oneparameter motions, the emergence of robotics changed the focus of kinematics to multi-parameter motions and new topics such as workspace computations, direct and inverse kinematics and singularities of sophisticated robots and machines. Therefore it is not surprising that researchers of the IFToMM community entered the new field of robot kinematics. Consequentially the TC Computational Kinematics was established within IFToMM. In this paper we introduce the basic topics and the research methods that define Computational Kinematics and report the short history, aims and activities of the IFToMM TC Computational Kinematics.

Introduction Although machines have been used since ancient times, the first theoretical works on the basics of motion go back to Antiquity; it seems that the Greeks were the first to study the theory of basic machines, the inclined plane, the wedge, the lever, the wheel and the screw [1]. Theoretical interest in kinematics, but most the time with some practical

D. Pisla (*) Department of Mechanics and Computer Programming, Technical University of Cluj-Napoca, Memorandumului 28, 400114 Cluj-Napoca, Romania e-mail: [email protected]; [email protected] M.L. Husty Institute of Basic Science in Engineering, University Innsbruck, Unit Geometry and CAD, Technikerstraße 13, Innsbruck A-6020, Austria e-mail: [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_9, © Springer Science+Business Media B.V. 2011

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applications in mind, started again in renaissance time. Texts from Antiquity such as books from the Aristotelian school were studied and enriched by their own results from researchers and engineers like Guidobaldo del Monte or G. Galilei. T. Koetsier came to the conclusion: “During the Renaissance MMS (Mechanism and Machine Science) did not exist as a coherent discipline, but in the textbooks of the descriptive type as well as in the books about basic machines the geometric aspect is in the centre” ([1], p. 8). The important fact is that geometric and topological properties were studied to explain force input and output relations of various mechanisms. Kinematics as a subject of its own appeared in the beginning of the nineteenth century when A.-M. Ampère in 1834 coined “the word “kinematics” (“cinématique”) for a subscience of mechanics, which deals with motion independent of its causes” ([1], p. 12). This interesting history of the early development of kinematics as a science between geometry and mechanics is explained in great detail in [1]. It is shown there that in the first half of the nineteenth century kinematics consisted of two (sometimes overlapping) main research directions: “Theoretical Kinematics”, mostly conducted by mathematicians interested in the geometry of motion and “Kinematics of machines” which deals more with the topology of mechanisms and the applications. The center of gravity of kinematics research at that time was clearly France and the important developments are linked to famous mathematicians like M. Chasles, A. Chauchy or É Bobillier. In the second half of the nineteenth century kinematics developed into an independent subject thus entering the golden age of kinematics ([1], p. 15). The center of gravity of kinematics research (at least for Theoretical Kinematics) moved eastwards and is linked to the names of Franz Reuleaux and Ludwig Burmester. The content of the kinematic research at that time was mostly kinematics of planar motions. Turning to spatial motions it became soon clear that the subject, from geometric and mathematical points of view became sophisticated. But still prominent mathematicians and geometricians were working in the field. As an example we cite the Pix Vaillant in 1904, when the French Academy of science under its president G. Darboux posed the question of determining all spatial continuous motions where as many points as possible move on spherical paths. E. Borel and R. Bricard won the prize but it turned out that in long and detailed discussions they only could give partial answers and many cases were not solved.1 Paradigmatic for all of kinematics, the equations describing those motions became too complicated to allow a complete answer (see also [2]). Equations describing the motion of spatial mechanisms, even when they have only one degree of freedom, are generally systems of algebraic or functional equations. They contain most of the time many parameters encoding the topology and the design of the mechanism and additionally are nonlinear in its motion parameters. More and more it became clear that interesting questions in kinematics were not solvable by hand, although appropriate mathematical tools generally were available. The systems of equations simply were too complicated to be handled. It seems that this is the most important reason that mathematicians at the beginning of the twentieth century lost interest in kinematics; it was no longer “fashionable” for mathematicians and geometricians to study kinematics and this led to a decline  A complete answer to this problem is still an open question. It should be noted that this question has become important again in the discussion of singularities and self-motions of Gough-Stewart platforms [2].

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of theoretical kinematics. Rather few papers on kinematics (compared to the golden period) were published in the first half of the twentieth century. Nevertheless theoretical kinematics survived at some singular spots, for example in Eastern Europe and in Austria. But in the second half of this century, because of the advent of Robotics, a renewed interest in the results of classical kinematics arose. Ferdinand Freudenstein, professor at Columbia University was the one who in the USA moved kinematics from its classical roots into a new age [3]. Therefore he is known as the father of modern kinematics, ushering in the programmed, digital computation era in the kinematics of mechanisms and robots. Freudenstein’s and his students’ work mark the transition of classical kinematics into a new paradigm. The idea to use the new technologies and computational possibilities to advance in kinematics must have been the motivation to collect the classical results in O. Bottema and B. Roth’s book Theoretical Kinematics [4]. This book summarizes the main subjects of classical kinematics and treats them uniformly: Representation of Euclidean displacements, instantaneous kinematics, more position theory, continuous kinematics, spherical and planar kinematics, special motions, kinematic mapping, non-Euclidean kinematics. It also defines the subject and marks the beginning of a renaissance of this science under a new paradigm: “Formally, kinematics is that branch of mechanics which treats the phenomenon of motion without regard to the cause of the motion. In kinematics there is no reference to mass or force; the concern is only with relative positions and their changes. We have used the word theoretical kinematics in order to distinguish our subject from applied kinematics, which deals with the application of kinematics: to mechanical contrivances, to the theory of machines and to the analysis and synthesis of mechanisms. Most of what is written herein could be used to study mechanical devices. However, our aim is broader: what we give is the development of the theory independent of any particular application, a presentation of the subject as a fundamental science of its own right. By this we hope to make these results equally accessible to other fields. This is important because our science touches on many areas: everything that moves has kinematical aspects.” ([4], preface). Although the book marks a change of paradigm it is still very classic and does not reflect the dramatic change of topics and methods in kinematics that caused the real renaissance of kinematics in the second half of the twentieth century. Because of robots and manipulators, multi-parameter motions had to be discussed, which were not in the interest of classical kinematics. Classical kinematics did not go further than two and three parameter motions. But the most influential change was the use of computers for both numerical and symbolic computations. Also problems where classical kinematics had to stop could be attacked again and new questions emerged. This marks the start of a new subscience of mechanics: Computational kinematics.

Computational Kinematics Computational Kinematics is that branch of kinematics that involves intensive computations not only of numerical type but also of symbolic nature [5]. This field has developed within the last 4  decades to answer fundamental questions arising in the analysis and synthesis of kinematic chains. These kinematic chains

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are constituent elements of serial or parallel robots, wired robots, humanoid robots, walking and jumping machines or rolling and autonomous robots. The fundamental questions, going far beyond classical kinematics, involve the number of solutions, complex or real to, for example, forward or inverse kinematics, the description of singular solutions and the mathematical solution of workspace or synthesis questions. Such problems are often described by systems of multivariate algebraic or functional equations and it turns out that even relatively simple kinematic problems involving multi-parameter systems lead to complicated nonlinear equations. Numerical solutions, using for example the Newton– Raphson method, yield in general to one isolated solution heavily depending on the initial value. This is an unsatisfying situation, because a safe control needs all solutions and even more, a clear understanding of all special solutions, which are mostly called singular solutions. This situation led to the application of new methods to kinematic problems, methods that had been previously developed in mathematics: • Numerical continuation is a method coming from the field of numerical algebraic geometry that allows one to find all solutions of a set of algebraic equations. • Groebner bases are a tool from algebraic geometry that uses symbolic computation to simplify systems of nonlinear equations, preferably into triangular form. Groebner bases are just one example of methods and algorithms from algebraic geometry that have been used in kinematics. • Interval analysis is an established numerical method although it is not well known. It is able to solve relatively large systems of equations providing all solutions within a bounded domain in a guaranteed manner (i.e., no solution can be missed), taking into account numerical round-off errors. Solutions are provided as ranges that are guaranteed to include a single solution of the system, a solution that can then be computed with an arbitrary accuracy. • Numerical optimization techniques such as genetic algorithms, sequential quadratic programming, gradient-based methods, simulated annealing or Monte Carlo methods are used in different variants and combinations. A more detailed discussion on the different mathematical methods applied within computational kinematics can be found in [6]. In this paper the authors state, “that the power of advanced mathematical methods is still far from completely utilized” [in computational kinematics]… and that “it is believed that the future of computational kinematics is directly linked to the development of mathematical tools for kinematics problems”. Both observations are indeed interesting. Kinematic problems and their solutions have not only been excellent examples for mathematicians to test their methods on, but on the other hand have forced mathematicians to improve those methods and even develop new tools. An example to support this statement is the development of the so-called witness set method within numerical continuation, which was developed to describe the behaviour of pathological mechanisms where the influence of design parameters change the kinematic performance of topologically equivalent mechanisms [7]. That certain useful ­mathematical

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methods were still not used within the community led to initiatives of the TC Computational Kinematics which will be discussed in Objectives and Activities of TC-Computational Kinematics. Nowadays kinematic questions cannot be treated in isolation. Dynamics, control and manufacturing of a device heavily interact with the kinematics. But it can be said that kinematics is the basis for all the other issues and a bad kinematic design will never be enhanced by a sophisticated control system. An exemplary selection of topics studied in Computational Kinematics is: • Analysis of robots and mechanisms –– –– –– –– –– • • • • •

Direct and inverse Kinematics Singularities Workspace Motion planning Collision avoidance

Redundant manipulators Structural synthesis of robots and mechanisms Performance analysis Compliance Calibration

This list is not exhaustive but it gives an impression of the research topics of the field. Computational Kinematics also has close links to and intense interactions with related fields like computational geometry, algebraic geometry, and numerical mathematics. But we note that it is difficult to establish exact boundaries between computational kinematics and e.g. dynamics, control, design and other subjects necessary to study robotic mechanical systems. This fact can be seen clearly from the following topics of the last Workshop on Computational Kinematics held in Duisburg (Germany) in 2009: Analysis of cable-driven parallel manipulators, motion planning, numerical methods, geometrical methods, synthesis of mechanisms and robots, biomechanics, design issues, singularities and gears.

History of TC-Computational Kinematics The IFToMM community has clearly observed the developments within kinematics and reacted in the early 1990s with the establishment of a Technical Commission on Computational Kinematics. Bahram Ravani first proposed the establishment of such a technical committee at the Executive Council Meeting of IFToMM in Sevilla, Spain on the occasion of the seventh World Congress of IFToMM in 1987. But it seems that the time was not ripe. The proposal was not approved. Bahram Ravani re-proposed the establishment of a technical committee with the name of “Technical Committee on Computational Geometry” at the executive council meeting at the occasion of the eight World Congress of

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IFToMM in Prague in 1991. This was approved with Bahram Ravani as the inaugural chair of this newly formed committee. A first workshop on Computational Kinematics was organized in Dagstuhl (Germany) by J. Angeles, G. Hommel and P. Kovacs. This workshop was the first in a series of workshops, but it seems that it was not organized under the auspices of IFToMM and the newly founded TC. The papers presented were published by Kluwer Academic Publishers [5]. In 1994, Bahram Ravani organized the first IFToMM workshop on the subject in conjunction with the fourth ARK workshop in Ljubljana, Slovenia July 4–6, 1994. The papers were published in a combined volume titled: “Advances in Robot Kinematics and Computational Geometry” co edited by Jardan Lenarčič and Bahram Ravani [8]. In 1995, at the executive council meeting at the occasion of the ninth World Congress of IFToMM in Milan, Bahram Ravani proposed the name change to “Technical Committee for Computational Kinematics” which was approved with Bahram Ravani as the chair. In 1995, the second workshop of the committee was held in Sophia-Antipolis, France on Sept. 4–6. The papers of this workshop were published in a bound volume with the title: “Computational Kinematics 1995”. It was co-edited by J. P. Merlet and B. Ravani and published by Kluwer Academic Publisher [9]. From this year on it was planned to have two conferences under the umbrella of the TC: ARK (Advances in Robot Kinematics) every even year, and CK (Computational Kinematics) every odd year. This splitting implicates that every second CK is held within the IFToMM world congress. Unfortunately these plans were destroyed already in 1997, when the scheduled CK workshop in Salford was cancelled by the organizers without clear reasons. In 1998, Jean Pierre Merlet was appointed as the chair of the Technical Committee on Computational Kinematics until 2005. Because of the cancelling of CK 1997 a long gap developed in the workshop series of Computation Kinematics. Not until 2001 did Frank Park revive the workshop series [10]. Because of the long gap and the unclear early history of this workshop it was wrongly named second workshop of CK. Following the success of this event CK was held every second year: 2003 (within the IFToMM world congress, actually held in 2004, because of SARS) in Tianjin (China), 2005 in Cassino (Italy) organized by M. Ceccarelli publishing the papers in conference proceedings on CD [11] and the best papers in a special volume of Mechanism and Machine Theory, 2007 in Besançon (France) within the IFToMM world congress and 2009 in Duisburg (Germany) organized by A. Kecskeméthy with proceedings in a bound volume [12]. It is a clear sign of gaining strength of the community and the workshop that the next two workshops of the CK series are already contracted to Barcelona (Spain) in 2013 and 2017 in Sousse (Tunisia). The conference series ARK had a much more stable history. This workshop has been held regularly since 1988 and since 1994 has been under the umbrella of the TC Computational Kinematics. Since then it was held every second year at different places. The proceedings of ARK are published by Springer in the book series Advances in Robot Kinematics [8, 13–20]. From 2005 until 2008 M. Husty was chairman of the TC and since 2009 Doina Pisla is the current chairperson.

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Objectives and Activities of TC-Computational Kinematics TC Computational Kinematics was established within IFToMM as a suborganisation and therefore committed to all objectives and activities of IFToMM. Nevertheless it has some special duties and responsibilities [21]: • To support and develop research and education in Computational Kinematics; • To establish contacts between researchers and engineers; • To promote the exchange of information; • To support the celebration of events. The main activities of the Technical Committee for Computational Kinematics, as listed in [21] are: The TC for Computational Kinematics • Helps to exchange the experiences and the knowledge in the International Computational Kinematics Community (conferences, publications) and to build up international research joint collaborations; • Decides about new members for the Technical Committee; • Discusses the topics, the locations and dates of coming international Computational Kinematics conferences; • Looks for support for young delegates from poor countries to visit conferences; • Reviews the conference papers and selects best papers for awards; • Evaluates new research directions and decides the introduction of new subcommittees; • Supports and recommends education activities in Computational Kinematics (short courses, University courses, summer schools and student exchange programs). The Technical Committee has a chairperson and a secretary, who are elected by the committee members. The duties and responsibilities of the chairperson- supported by the secretary are: • Organize and coordinate the TC-meetings (usually during one of the Computational Kinematics workshops or whenever a majority of TC members meet at other conferences); • Invite for the meetings, prepare the agenda, write the minutes of the meetings and distribute them to the TC-members; • Lead the discussion during the meetings and asks the members for decisions by votes; • Report about the general IFToMM activities, e.g. results of the Executive Council meeting, IFToMM world conferences etc; • Report yearly to the IFToMM Executive Council about the annual activities of the Technical Committee;

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• Ask and negotiate with the Executive Council and the treasurer about support for the Technical Committee and for the young delegates’ program. • The chairperson and the secretary are responsible for the execution of decisions from the Technical Committee.

Conferences As already explained in History of TC-Computational Kinematics the IFToMM Technical Committee for Computational Kinematics is linked to two important conferences: 1. International Symposium - Advances in Robot Kinematics (ARK) is a series of international symposia of the highest international level organized every 2 years since 1988. The last ARK was organized in Batz sur Mer, France (2008) and ARK 2010 will be organized in Piran, Slovenia. Following the definition of the organizers of ARK 2010 [22] it provides a forum for researchers working in robot kinematics and stimulates new directions of research by forging links between robot kinematics and other areas. The main topics are as follows: Analysis of robot kinematics; Modelling and simulation of robot kinematics; Kinematic design of robots; Kinematics in robot control; Theories and methods in kinematics; Singularity and isotropy; Kinematics in biological systems; Kinematics in parallel robots, redundant, humanoid robots. The ARK papers are included in books published by Springer (previously by Kluwer). These books present the most recent research advances in the theory, design, control and application of robotic systems, which are intended for a variety of purposes such as manipulation, manufacturing, automation, surgery, locomotion and biomechanics. 2. International Workshop on Computational Kinematics (CK) The aim of this workshop is a little bit broader then ARK. This can be seen already in the title of the workshop, because Computational Kinematics is not limited to the kinematics of robots. It comprises the kinematics of all types of mechanical systems. The scope of the conference includes the following topics: Kinematic design and synthesis; Computational geometry; Motion analysis and synthesis; Theory of mechanisms; Mechanism design; Kinematical analysis of robots and parallel manipulators; Kinematical issues in biomechanics; Molecular kinematics; Computer animation and interpolation of kinematical motion; Motor learning and control; Robot motion planning; Applications of computational kinematics; Education in computational kinematics; Theoretical foundations of kinematics. It should be mentioned that none of the conferences is strict in accepting papers of topics within kinematics that are not explicitly listed. The main criteria of acceptance are the quality of the contributions.

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Summer Schools Dissemination of new methods among young researchers is one of the most important issues in establishing a new scientific field. Therefore it is one of the important tasks of the TC Computational Kinematics to provide courses, textbooks and summer schools for PhD students and young scientists. In summer 2009 the TC organized a summer school on “Mathematical Methods in Computational Kinematics” in Innsbruck (Austria). For 4 weeks, intense lectures were given on methods from algebraic geometry and their application to kinematics, numerical continuation and interval analysis. In lectures and lab exercises, students learned about the foundations of algebraic geometry, e.g., ideals and varieties, term orders and Groebner bases, elimination theory, dimension of ideals and primary decomposition, numerical algebraic geometry, e.g., homotopy, solution paths, total degree homotopy, parameter continuation, numerical irreducible decomposition and the use of software packages such as HomLab and Bertini. They were introduced into interval analysis and learned how to set up and solve kinematic problems with interval methods and how to obtain certified solutions with the software package ALIAS.

Journal In 2002 the TC launched an electronic journal EJCK (Electronic Journal of Computational Kinematics. It was intended to act as a complement to classical journals while retaining their high quality and to improve the availability of scientific materials through electronic distribution [23]. The journal encouraged “the full use of the computer media [..]: this includes computer animation through the Web (possibly interactive), possibility of free software downloading, interactive use of software}” [23], and wanted to provide the possibility to an update of some previously published paper and to have a review of the updated version. This possibility should enable “evolving papers with a minimal amount of work from the authors, the reviewers and the readers” [23]. It wanted also to “encourage online discussion of articles or the submission of open problems, a process as vital to the community as the formal publication process itself”. The main topics of the journal were intended to be: • • • • • • • •

forward and inverse kinematics of mechanisms and robots advances in theoretical kinematics workspace computation singularity evaluation path planning, trajectory interpolation performance evaluation of mechanisms optimal design of mechanisms methodology for designing new mechanisms

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The first volume of the journal was published in 2002 and contained 28 papers. Unfortunately this issue was the only one published. There might be many reasons why this journal was not accepted by the community. Perhaps the time was not ripe for an electronic journal, although the format was exactly what the field needed. Papers in Computational Kinematics need some important publication in which to present electronic material, like symbolic software worksheets, computer code for algorithms, animations or high resolution figures. For many years the TC had discussions about advertising and relaunching the journal. In the TC meeting, which was held at the IFToMM world congress in Besançon in 2007, the then members of the TC decided to stop the discussion about relaunching the journal. This decision was approved by the Executive Council in the meeting in 2007. The TC should rethink this decision because times have changed and the basic fear of the authors, that an electronic journal may not be taken as seriously as a regular paper journal, has at least partly been overcome by the development of scientific publishing within the last 5 years. It seems to be clear that a scientific field that heavily uses the computer to derive results needs a publication forum that allows publication of animations, videos, long computer code, algorithms and high resolution figures.

Conclusion Since the middle of the twentieth century, kinematics has been revived because of the new possibilities the computer revolution brought, but also because of a dramatic change of the subject itself. In this paper we have tried to trace this development, which led to the establishment of a Technical Commission within IFToMM. We have tried to define the subject and list the activities the TC has put forth. Acknowledgement  The authors thank Bahram Ravani for his input on the early history of the TC.

References 1. Koetsier, T.: Mechanism and machine science: its history and its identity. In: Ceccarelli, M. (ed.) Proceedings of HMM 2000, pp. 5–24. Kluwer Academic (2000) 2. Husty, M., Borel’s, E., Bricard’s R.: Papers on Displacements with Spherical Paths and their Relevance to Self-motions of Parallel Manipulators, In: Ceccarelli, M (ed.) International Symposium on History of Machines and Mechanisms-Proceedings HMM 2000, pp. 163–172, Kluwer Academic (2000), ISBN0-7923-6372-8 3. Roth, B.: Ferdinand Freudenstein (1926–2006). In: Ceccarelli, M. (ed.) Distinguished Figures in Mechanism and Machine Science, pp. 151–181. Springer, New York (2007) 4. Bottema, O., Roth, B.: Theoretical Kinematics. North Holland, Amsterdam/New York (1979) 5. Angeles, J., Hommel, G., Kovacs, P. (eds.): Computational Kinematics. Kluwer, Dordrecht (1993). ISBN ISBN-10: 904814342X ISBN-13: 978-90481434291993

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6. Luo, Z., Dai, J.S.: Mathematical methodologies in computational kinematics. In: 14th Biennial Mechanisms Conference, Chong Qing, China, 2004. Also published in Journal of Machine Design and Research, 20 (special issue) (2004) 7. Sommese, A.J., Wampler, Ch W.: The Numerical Solution of Systems of Polynomials. World Scientific, New Jersey (2005) 8. Lenarčič, J., Ravani, B. (eds.): Advances in Robot Kinematics and Computational Geometry. Springer, Dordrecht (1994) 9. Merlet, J.-P. (ed.): Computational Kinematics 1995. In: Proceedings: Workshop on Computational Kinematics Held in Sophia Antipolis, 4–6 Sept 1995. Kluwer Academic, Dordrecht, ISBN13: 9780792336730 ISBN10: 0792336739 (1995) 10. Park, F.C., Iurascu, C.C. (eds.): Proceedings of the 2nd Workshop on Computational Kinematics, Seoul, 20–22 May 2001 11. Ceccarelli, M. (ed.): CD Proceedings of CK05 IFToMM Workshop on Computational Kinematics, Cassino, 4–6 May 2005 12. Kecskeméthy, A., Müller, An (eds.): Computational Kinematics. Springer, Duisburg (2009). ISBN ISBN 978-3-642-01946-3 13. Stifter, S., Lenarčič, J. (eds.): Advances in Robot Kinematics: With Emphasis on Symbolic Computation. Springer, Wien/New York (1991) 14. Lenarčič, J., Parenti-Castelli, V. (eds.), Recent Advances in Robot Kinematics. Springer (1996) 15. Lenarčič, J., Husty, M.L. (eds.): Advances in Robot Kinematics: Analysis and Control. Springer (1998) 16. Lenarčič, J., Stanisic, M.M. (eds.): Advances in Robot Kinematics. Springer (2000) 17. Lenarčič, J., Thomas F. (eds.): Advances in Robot Kinematics: Theory and Applications. Springer (2002) 18. Lenarčič, J., Galletti, C. (eds.): On Advances in Robot Kinematics. Springer (2004) 19. Lenarčič, J., Roth, B. (eds.): Advances in Robot Kinematics: Mechanisms and Motion. Springer (2006), ISBN-10: 1402049404 ISBN-13: 978–1402049408 20. Lenarčič, J., Wenger P. (eds.): Advances in Robot Kinematics: Analysis and Design. Springer (2008) 21. http://130.15.85.212/link/TCdata.html, (2009) 22. http://www.ijs.si/ijsw/IJS/ARK2010 23. http://www-sop.inria.fr/coprin/EJCK/EJCK.html, (2000)

Theory and Practice of Gearing in Machines and Mechanisms Science Veniamin I. Goldfarb

Abstract  Some tendencies of theory and practice of gearing development, a bit of history with the names of outstanding scientists and engineers, the up-to-data directions of research and development activity in the field of gears are given in the chapter.

Introduction One of the greatest inventions of humanity was and remains the wheel, without which we could hardly imagine our existence. The wheel, in turn, provided civilization with many derivatives, including such a wonderful one, the gearwheel that, paired with another gearwheel, forms a gear. For over 400 years, gears have been the most fundamental and reliable mechanisms for transmission and transformation of motion. During this long period humanity did not manage to think of anything more perfect, but continued developing and improving this kind of mechanisms. It is hardly possible to find a field of technology today where gears are not used. Neither power plants generating thousands of megawatts of power, nor spindles of metal-cutting machine-tools, nor car wheels, nor hands of watches, nor platforms of huge excavators with gear rims of diameter up to 20  m, nor micromechanisms with the size of gears less than 1 mm, could rotate without them. And thus the activity of gear designers, researchers, manufacturers and consumers does not decrease, the number and complexity of problems solved by experts keeps growing, gear application domains are expanding, and world gear production and consumption keeps growing annually, exceeding today 100 billion USD.

V.I. Goldfarb (*) Department of Production Engineering, Institute of Mechanics, Izhevsk State Technical University, Studencheskaya str. 7, Izhevsk 426069, Russia e-mail: [email protected]; [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_10, © Springer Science+Business Media B.V. 2011

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A Bit of History Historically, methods of geometrical analysis of gears began developing in the sixteenth century. Works of G. Cardano (1557), P. De La Hiro (1694) and L. Euler (1754) were the reference point for theory of involute cylindrical gears design. The theory of gearing appeared as an independent science in the nineteenth century due to fundamental works of T. Olivier (1842), who presented it as a section of descriptive geometry, and H.I. Gochman (1886), who generalized and developed the theory of gearing by methods of mathematical analysis. The twentieth century became an era of revolutionary changes in technology on the whole, including technology of gearing and theory of gearing. These changes are connected with the names of many remarkable scientists and engineers: E. Wildhaber (1893–1976) was the most famous researcher in the field of gear design and manufacture – he received 279 patents, many of them are in practical use even now; E. Buckingham (1887–1978) was another of the outstanding researchers who laid the foundation of modern methods of gear design; D. Dudley (1917–2003) was a scientist with encyclopaedic education, his textbooks and reference-books were published in huge amounts and were always useful in engineering practice; G. Niemann (1899– 1982) was an outstanding scientist and teacher in the field of machines and mechanisms design; D. Brown, W. Gleason, G.A. Klingelnberg are consummate organizers, who created world-wide known companies for the manufacture of gears and tooth-cutting machine-tools; H. Merrit, H. Winter, N.I. Kolchin, V.A. Gavrilenko, V.N. Kudryavtsev, M.L. Novikov, A. Seireg, G. Henriot, E.L. Airapetov and many other scientists and engineers, who left bright imprints in the science of gears and practice of their wide application, and who are carefully kept in our memory. Modern scientists Prof. F.L. Litvin – an outstanding creator of geometrical theory of gearing and one of most cited scientists, Professors A. Kubo, B.-R. Höhn, D. Qin, W. Predki, A.E. Belyaev, V.E. Starzhinsky, D. Houser and many others from all countries of the world actively keep developing the theory of gearing, which, like other sections of machines and mechanisms science, is improving together with the world progress of science and technology. It is impossible to cite here all the individuals who created and developed the theory and practice of gearing, and to give corresponding bibliographic references; I would like however to mention the unique books by Faidor L. Litvin [1, 2], H.-Chr. Graf Seher-Thoss [3], Darle W. Dudley [4], Hermann J. Stadtfeld [5], which contain the best descriptions of the developmental history of the theory of gearing. Some very important information about that history relates to the creation and activity of the Gearing Technical Committee of IFToMM. The idea of creating the Committee was proposed in 1976 by Prof. A. Morecki, who was at that time the Secretary General of IFToMM and invited a famous scientist, D.W. Dudley (USA), to head the Committee. The directions of the Technical Committee’s activity (dynamics, load-bearing capacity, efficiency, techniques of gear manufacture, differential gear mechanisms) were outlined at the first Committee meetings, which were held, as a rule, within the framework of large conferences on gears and transmissions. The first Committee was formed and it included Prof. G. Henriot

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(France), Prof. M. Dietrich (Poland), Prof. Z. Terplan (Hungary), Prof. H. Winter (Germany), Dr. K. Stölzle (Germany), Prof. A. Kubo (Japan), Prof. J. Hlebanya (Yugoslavia) and other famous scientists and engineers. In 1986 Dr. K. Stölzle took the place of D.W. Dudley in the post of Chairman. Under his chairmanship the meetings were carried out in the framework of large conferences in France, China, Japan, USA and together with meetings of the Gearing Committee (TC60) of ISO. Two important directions were chosen for TC activity: (1) calculation of gear overloading that appear, in particular, during their abrupt stoppage; (2) determination and application of various factors during calculation of a gear’s load-bearing capacity. From 1993 to 1997, the Committee was headed by Prof. A. Kubo (Japan), who surveyed the members of TC, asking the question of what research activity the Committee should foster in the coming years. That survey resulted in a mission statement – to determine the most urgent needs of gear engineers and scientists and to develop recommendations and proposals for improving the quality of their scientific-technical production. During this period a program of international conferences on motion and power transmissions was developed. During these years also the Journal “Gearing and Transmissions” began publication; it was at first considered as a Journal of the Technical Committee but later became one of the official Journals of the IFToMM. V.I. Goldfarb (Russia) became the Editor-in-Chief of the Journal, and the Editorial Board was formed of many leading gear experts from many countries, including some members of TC. In 1997 Prof. V.I. Goldfarb was elected the Committee Chairman. At the first meeting in the city of Tun (Switzerland), which took place together with the meeting of ISO TC60, he proposed a program for the Committee consideration, according to which the following directions were outlined: joint realization of scientific programs and projects, carrying out conferences and scientific seminars, cooperation with national associations and other gear organizations; publishing, educational, informational activity. This program was agreed to by the Committee. The theme “Development of methods and tools of estimating the state and diagnostics of gears and gearboxes” was suggested as a priority for joint scientific research projects. Universities of Russia, Slovakia, Poland, Czech Republic, and Belarus cooperated in realization of an international program. The Journal “Gearing and transmissions” was published regularly from 1994 to 2004 under the direction of experts from 22 countries who were Committee members. In 2005, Prof. A. Dobroczeny (Hungary) was elected the Committee Chairman.

Development Trends of the Theory and Practice of Gears Let us begin with a statement by Dr. Stölzle given in the paper [6]: “Gearing is necessary evil. It is always positioned between its competitive brothers, i.e., the prime mover and working machinery. Gearing cannot be alive by itself alone, which means it can exist as a function of driving and driven machines. The development of gearing follows therefore always the development of driving and driven machines.”

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Such a humorous, but quite correct in its essence, definition of the role of gears makes it quite clear that trends of their development depend crucially on innovations in drives and actuators. These trends are as follows: increase of operating speeds and loads, reduction of dimensions, improvement of accuracy, safety and durability. New fields of gear application are emerging, setting new specific demands: inadmissibility to use lubrication, in particular, in vacuum or some aggressive medium; necessity of abrupt reduction of overall dimensions and increasing compactness during operation in a very limited space envelope, for example, when carrying out medical and biological research; necessity of adaptation to new operating conditions with memorization of the previous state; necessity of uninterruptible operation for a very long period of time and so on. The trends mentioned above were crucial determinants of the directions of gear development and research in this field of technology. In order to identify these directions, the themes of papers presented at the largest conferences on gears and transmissions for the last 15 years since 1994, were analyzed. The analysis indicated the following. The largest number of works (24.5%) is devoted to dynamics, strength and load-bearing capacity, among them the works [7–16 and many others] should be singled out. Conventionally, great attention (18.1% of reports) is paid to research into the geometry of the gearing, particularly, of the spatial one, such as spiral bevel gears, worm, spiroid and hypoid gears [17–23 and many others]. Technology, equipment, manufacturing are the theme of 18% of the reports; new design units – 11.5%; experimental research – 7.1%; CAD/CAM, simulation – 6.6%; vibration and noise – 6.2%; application – 3.7%; materials, lubrication, wear – 2.8%. Unfortunately, only 1.5% of reports consider questions of accuracy, which are of utmost importance for today’s manufacturers. Actually the number of publications annually is far from the number of reports at the leading conferences. Nevertheless, the mentioned data rather objectively reflect the existing directions of activity in the field of gears. Development of the theory of gearing is a story of the trends mentioned above and the changing requirements of gears. A great number of kinds of gears and mechanisms based on these requirements, often differing in a large number of features, have been created over these past years. New gear classifications have been developed and are being improved; methods for the synthesis of new kinds of gears with specific properties are being developed. The high degree of formalization of some synthesis problems makes computer-aided solution possible [24]. Methods of simulation and research into the geometry and kinematics of gearing, as well as evaluation of force and strength factors, are of major importance in the science of gearing. Universal simulation methods as tools for gear design and research are being developed. The task is to describe processes in the contact of active flanks that will facilitate actual gearing, i.e., taking into account inevitable manufacturing and assembly errors and the actual state of surfaces and deformations of gear elements. In recent years a new term “theory of actual gearing” has been coined, that covers the mentioned trends.

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As shown above, increased attention is being paid to research into gear dynamics. At present three levels of dynamics research can be outlined: gearing dynamics, i.e., dynamic processes in the highest-order kinematic pair, which is a pair of meshing teeth; dynamics of a gear consisting of driving and driven elements with their shafts, bearing supports, casing; and, at last, dynamics of a machine aggregate, including a gear. It is not always possible to build adequate mathematical models, because theory cannot answer numerous questions such as: how do resistance forces change in certain instances with account of every factor characterizing the gearing – state of the surfaces, lubrication and many others; what is the connection between mechanical vibrations in the mesh and noise emitted by the gear; as well as many other questions. The only source that allows us to find answers to such questions is experiment. Modern techniques and methods of experimental research make possible determination with high accuracy of the quality of gears and further operational factors – load-bearing capacity and efficiency, finding reasons for damage initiation and gear failure. Today there are unique testing rigs not only with great measuring abilities, but which allow one to generate load by predefined law for the tested gears, simulating various operating conditions and motion on the driving link. Methods of gear lifetime estimation have been developed by means of integral strain gauges, which are thin metallic films accumulating information about the fatigue-stressed state of gear elements, recognition techniques for this sort of information have been developed as well [25, 26]. Methods and corresponding instrumentation for early diagnostics of gear defects by means of acoustic emission effect have emerged; they are of great importance for gears of machines, where any damage leads to huge economic losses or is connected with the safety problem [27, 28]. Gear manufacturing technology is directly linked with the theory of gearing. Technological synthesis of a gear with defined properties is one of the most difficult tasks in the theory of gearing. According to several experts’ estimation, abilities of up-to-date tooth-cutting equipment exceed not only abilities of gear researchers and designers, but sometimes also their fantasy. The task of the theory of gearing is not only to use these abilities, but also to propose new geometrical and kinematic schemes for generation of teeth flanks, not only by the methods of cutting, but by plastic deformation, electric and chemical treatment and others. Manufacturing technology also assumes methods of providing the required physical and mechanical properties of teeth surfaces that meet required strength and antifriction characteristics. At present methods for calculation gears with modified strengthened surface layer of gearwheels’ teeth and technologies, in particular, laser technologies, ensuring the required properties, are being developed. Questions of rational choice of gearwheel material and lubrication to provide required gear quality play a great, and sometimes critical, role. The information mentioned above comprises only an incomplete list of directions and trends of development of the theory and practice of gearing that appear and become refined in the light of new knowledge about machines and mechanisms.

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Conclusion I would like to quote Prof. A. Kubo [6] again, who says “Gear technology is not a frontier technology that is beautifully informed and advertised to public through masscommunication media, the feasibility of such frontier technology is although in question. Gear technology is a technology to support today’s human life. Such kind of technology is more important practically, when we want to enjoy our high level of living, because we always need physical power to cultivate land, to produce foods, to move or travel and so on.” These words need no further comment. We should advance mechanisms and machines together with the gears they constitute and carefully transfer accumulated knowledge and experience to the next generation of engineers and researchers.

References 1. Litvin, F.L.: Theory of Gearing. Nauka, Moscow (1968) (in Russian) 2. Litvin, F.L.: Development of Gear Technology and Theory of Gearing. NASA Reference Publication 1406, Cleveland (1998) 3. Seher-Thoss, H-Chr: Die Entwicklung der Zahnrad-Technik. Springer, New York (1965) 4. Dudley, D.W.: The Evolution of the Gear Art. American Gear Manufacturers Association, Washington, DC (1969) 5. Stadtfeld, H.J.: Handbook of Bevel and Hypoid Gears: Calculation, Manufacturing and Optimization. Rochester Institute of Technology, Rochester (1993) 6. Kubo, A.: Short history of the IFToMM Gearing and Transmissions TC. Gearing and Transmissions, No2, pp. 4–13 (1996) 7. Airapetov, E.L., Aparkhov, V.I., Evsikova, N.A., Melnikova, T.N., Filimonova, N.I.: The model of teeth contact dynamical interaction in the spur gearing. In: Proceedings of Nineth World Congress on TMM, Milano, pp. 459–461 (1995) 8. Kahraman, A., Blankenship, G.W.: Gear Dynamics Experiments. In: Proceedings of the 7th International Power Transmission and Gearing Conference. ASME, San-Diego, part I – pp. 378–380, part II – pp. 381–388, part III – pp. 390–396 (1996) 9. Gosselin, C., Gagnon, Ph., Vanjany, J.-P.: Loaded tooth contact analysis of spur, helical and hypoid gears based on the finite strips and finite prisms models. In: Proceedings of the 4th World Congress on Gearing and Power Transmissions, Paris, pp. 29–42 (1999) 10. Umezava, K., Matsumura, S., Houjon, H., Wang, S.: Investigation of the dynamic behaviour of a helical gear system. In: Proceedings of the 4th World Congress on Gearing and Power Transmissions, Paris, pp. 1981–1990 (1999) 11. Velex, Ph.: Some problems in the modeling of gear dynamic behaviour. In: Proceedings of the JSME International Conference on Motion and Power Transmissions, Fukuoka, pp. 45–50 (2001) 12. Höhn, B.-R., Michaelis, K., Rank, B., Steingrover K.: Investigation of the pitting resistance of worm gears. In: Proceedings of the JSME International Conference on Motion and Power Transmissions, Fukuoka, pp. 156–161 (2001) 13. Velex, Ph.: On the relationship between gear dynamics and transmissions errors. In: Proceedings of the JSME International Conference Motion and Power Transmissions, Sendai, pp. 249–254 (2009) 14. Qin, D., Wang, J., Wu, X.: Flexible multibody dynamic model of coupled planetary gear and bearing. In: Proceedings of the JSME International Conference Motion and Power Transmissions, Sendai, pp. 280–287 (2009)

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15. Octrue, M.: Load capacity calculation of worm gears: at the moment and for the future. In: Proceedings of the JSME International Conference Motion and Power Transmissions, Sendai, pp. 21–25 (2009) 16. Goldfarb, V.I., Trubachev, E.S., Kuznetsov, A.S. Load capacity of heavy-loaded low-speed spiroid gears. In: Proceedings of the JSME International Conference Motion and Power Transmissions, Sendai, pp. 280–285 (2009) 17. Visa, F., Miloiu, G.: Contact sensitiveness at spiral bevel gears. In: Proceedings of Ninth World Congress on TMM, Milano, pp. 406–410 (1995) 18. Seol, I.H., Litvin, F.L.: Computerized design, generation and simulation of meshing and contact of modified involute, Klingelnberg and Flender worm-gear drives. In: Proceedings of the 7th International Power Transmission and Gearing Conference, pp. 673–678. ASME, San-Diego (1996) 19. Stadtfeld, H.: The universal motion concept for bevel gear production. In: Proceedings of the 4th World Congress on Gearing and Power Transmissions, Paris, pp. 595–608 (1999) 20. Handschuh, R.: Comparison of experimental and analytical tooth bending stress of aerospace spiral bevel gears. In: Proceedings of the 4th World Congress on Gearing and Power Transmissions, Paris, pp. 557–570 (1999) 21. Höhn, B.-R.: Modern gear calculation. In: Proceedings of the International Conference on Mechanical Transmissions, pp. 1–2. Science Press, Chongqing (2006) 22. Goldfarb, V.I.: What we know about spiroid gears. In: Proceedings of the International Conference on Mechanical Transmissions, pp. 19–26. Science Press, Chongqing, China (2006) 23. Fan, Q., Dafoe, R.S., Swanger, J.W.: New developments in computerized design and manufacturing of spiral bevel and hypoid gears. In: Proceedings of the International Conference on Mechanical Transmissions, pp. 128–133. Science Press, Chongqing (2006) 24. Goldfarb, V.I., Malina, O.V.: Computerized synthesis of skew-axis gear scheme with given specification. In: Proceedings of the JSME International Conference on Motion and Power Transmissions, Fukuoka, pp. 441–455 (2001) 25. Syzrantsev, V.N., Golofast, S.L., Syzrantseva, K.V.: Gearing serviceability diagnostic with the help of integral strain gauges. In: Proceedings of the 4th World Congress on Gearing and Power Transmissions, Paris, pp. 1845–1850 (1999) 26. Syzrantsev, V.N., Golofast, S.L.: Cyclic Strains Measurement and Machine Parts Longevity Forecasting According to Integral Strain Gauges Indications. Nauka, Novosibirsk (2004) (in Russian) 27. Singh, A., Houser, D.R., Vijayakar, S.: Early detection of gear pitting. In: Proceedings of the 7th International Power Transmission and Gearing Conference, pp. 673–678. ASME, San-Diego (1996) 28. Goldfarb, V.I., Budenkov, G.A., Nedzvetskaya, O.V.: Development of the acoustic emission wave radiation model for gear damage diagnostics. In: Proceedings of the 4th World Congress on Gearing and Power Transmissions, Paris, pp. 2337–2346 (1999)

ThinkMOTION: Digital Mechanism and Gear Library Goes Europeana Burkhard Corves, Torsten Brix, and Ulf Döring

Abstract  The most important aim of the IFToMM is “to promote research and development in the field of Machines and Mechanisms by theoretical and experimental methods, along with their practical application” (see article 2.1 of the statutes [12]). This is strongly connected with access to current knowledge, experience and skills in the field of mechanism and machine science (resp. motion science). However this content is characterized by a high diversity and heterogeneity, because it is mostly scattered, represented in different forms (physical model, drawings, textbooks etc.), languages and mediums. Therefore there is a need to establish an open access, multilingual digital library in this field of techno-cultural heritage. Against this background, members of three IFToMM-Commissions initiated a joint project called thinkMOTION. In this project, which promotes the idea of open access, the techno-cultural heritage and the current developments in motion science will be widely accessible via Europeana, which is the search platform for European digital libraries initiated by the European Commission. The content is useful for a wide range of user groups, such as interested laymen, engineers, scientists, lecturers, pupils, students all over the world, in that it opens new possibilities in multilingual searching, browsing and using of information sources.

Introduction The thinkMOTION project is sustained by members of the IFToMM Permanent Commissions for the History of Mechanism and Machine Science (e.g., H. Kerle, M. Ceccarelli) and for Standardization of Terminology (e.g., A. Klein Breteler, B. Corves (*) R.-W. Technische Hochschule Aachen, Eilfschornsteinstrasse 18, Aachen, D 52056, Germany e-mail: [email protected] T. Brix and U. Döring TUI University of Ilmenau, Ilmenau, Germany M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_11, © Springer Science+Business Media B.V. 2011

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T. Brix, U. Döring) as well as the Technical Committee for Linkages and Cams (e.g., B. Corves, V. Petuya). All involved persons have the aim to establish a new sector in knowledge digitisation, retrieval and access with focus on technical knowledge that is stored in very heterogeneous forms like text documents, photos, videos, animations, technical drawings, calculation sheets, physical models etc. Previous digitisation projects often neglected technical, techno historical and techno cultural knowledge because non-technicians decide what content is to preserved for future generations. Thus especially technical knowledge tends to be buried in oblivion, although this knowledge is an inseparable part of mankind, which is to a great extend defined by technical developments and prosperity. thinkMOTION is a large scale project initiated by IFToMM members which allows the connection and publication of forgotten treasures of heterogeneous content to honour the creative genius of countless inventors, engineers and natural scientists, who have enabled and expedited technical progress in medicine, electrical, civil, mechanical, automotive engineering etc. Knowledge about mechanism and machine science that comes from a large variety of different countries is currently difficult to access. Historical books in mechanical engineering are of low availability. Sources such as private or educational collections of physical models are usually not open to the public. But even the existing access to public content does not comply with today’s requirements concerning rapid information retrieval. The heterogeneous sources that represent our knowledge about motion systems (Fig. 1) are widespread over a lot of institutions (museums, libraries and mainly universities) and professionals. Many of these sources are nonregistered material and hence not easily traceable. Therefore the first challenge of the thinkMOTION project is the collection of content as well as procurement of rights of use in an efficient way. For this the

Fig. 1  Examples for heterogeneous content in the field of motion systems (Brix et al. [1], Kerle et al. [2], Hüsing et al. [3], Corves and Kloppenburg [4])

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thinkMOTION project can use the experiences of the German digital library DMGLib (www.dmg-lib.org), Brix et al. [1]. To locate relevant content in each language, regional localized catalogues and lists of bibliographical references in books or from authors will be used. Additionally personal contacts will be utilized since they have proved to be very helpful. The focus is not only on textual documents, images and animations. Functional models, which exist in thousands of unique models with no or only very limited access for the public, are digitized too. This huge amount of available heterogeneous information resources in the DMG-Lib implies a key challenge of this project: the implementation of an efficient, uniform and user-satisfying information retrieval system, Rasmussen [5].

DMG-Lib as the Basis of ThinkMOTION DMG-Lib already contains a large amount of very heterogeneous information resources like books, journal publications, functional models, gear catalogues, videos, images, technical reports, etc. The original sources are procured, digitized and converted into suitable data formats. The information resources can be accessed worldwide on the DMG-Lib internet portal, Brix et  al. [1]. This simplifies the access and distribution of these information resources, but does not directly enhance a goal-oriented usage and retrieval of motion solutions for technical tasks in research and industry. Rather the common storage method for knowledge, mainly in static texts and images, does not comply with requirements of an efficient and fast information retrieval. The advantages of functional models for a better understanding of complex design and functionality principles are well known. Today Computer based methods enable the generation of multimedia documents that describe the function and other relevant attributes of mechanisms and gears and make them available for a broad public. Such multimedia documents can easily be distributed and enriched with extensive additional information as shown in Döring et al. [6]. An overview of the complex production workflow for the identification, digitalization, enrichment, storage and presentation of information resources in the DMG-Lib is displayed in Fig. 2. The only way to collect, enrich and present the complex domain specific heterogeneous information sources according to user requirements is the consequent cooperation of information, computer and usability scientists as well as engineers, librarians and experts of mechanism and gear science with the following major topics:

Enrichment of the Information Resources Information sources (e.g.: literature, solid mechanism and gear models, educational material of participating departments) are digitized and integrated in the digital library.

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Fig. 2  Production workflow in DMG-Lib, Döring et al. [6]

Different meta-data are added to the documents such as administrative, descriptive and structural data (Fig. 3). The result of the structural and layout analysis is the identified logical structure of the document. This information can be used in further processing steps like the automated generation of links and tables of contents as well as in ranking of full text search results. For enrichment of the scanned documents an animation generator was being developed which allows simulation and variation of drawings, images and models in an easy and fast way.

DMG-Lib Online Portal The portal is the internet based communication and presentation interface between the user and DMG-Lib (Fig. 4). For a user adequate design and implementation, an evaluation of the usability was performed which is oriented on the Usability Engineering Lifecycle, Mayhew [8]. According to this method a requirement analysis and expert interviews have been carried out to develop a conceptual model of the DMG-Lib portal.

Information Access Searching and browsing are the central access ways to all information in DMG-Lib. For both possibilities the text-based search is a basic functionality to find all kinds

Fig. 3  Meta data organisation for a mechanism model, Corves et al. [7]

Fig. 4  DMG-Lib online portal (www.dmg-lib.org)

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Fig. 5  DMG-Lib online portal (www.dmg-lib.org)

of information from different sources. For representation of retrieved documents during the browsing and searching process, special viewers have been developed. All information about persons and metadata are represented in html pages. For working with full texts and enhanced, resp. enriched, animations, JAVA applications exist (Fig. 5).

The Importance for Users The aims of the digital library project thinkMOTION cover the goals of the European Commission defined within the Seventh Framework Program. The guiding idea is to “improve the free accessibility and usability of scientific content”, in particular addressing issues of interoperability and multilingual access which was formulated with respect to the main goal to “improve access to Europe’s cultural and scientific heritage”. The thinkMOTION project as part of Europeana (Purday [9]) will be designed to give different user groups from all over the world access to scientific and practical knowledge in the field of motion systems supporting both life-long learning and practical uses for different user groups. For this the project combines content and knowledge in the field of mechanical motion and provides public access to the whole knowledge space in several ways. The supply of videos,

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Fig. 6  From left to right Archimedes (287 v. Chr. – 212 v. Chr.), Agustin de Bétancourt y Molina (1758–1824) Ludwig Burmester (1840–1927), Kurt Hain (1908–1995), Willibald Lichtenheldt (1901–1980), Guilio Mozzi (1730–1813), James Watt (1736–1819) From: Ceccarelli [10]

technical drawings, interactive animations etc. is also an important approach that eases the understanding of movement systems for laymen as well as experts. Even for experts a deep comprehension of a quite simple movement system is only seldom possible when only a textual description is shown. There are two main reasons to build up a digital library of motion systems. The first is related to content. European mechanical engineers have a long tradition (see Fig. 6). Over the last centuries in all European countries a lot of inventions have appeared and scientific progress has been made. From the academic point of view, different schools of machine and mechanism scientists and design engineers arose and those schools mostly have a special focus on certain fields (e.g., spherical mechanisms, gear train mechanisms, compliant mechanisms, linear drives, dynamics, robotics, parallel kinematics, etc.) or different applications fields (medicine, electrical, civil, automotive engineering). That is why the content such as literature, and in particular mechanical models, are far-flung in Europe. Each nation has its own competence centers, often situated at universities or museums. This content is (if at all) only nationally accessible. Often access to the content is very time consuming for the users (e.g., interlibrary lending or travel to model collections). Therefore the content and the access rights must be collected in different European countries.

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The second reason to build up a European digital library of motion systems is the multilingualism of Europe. Only with the support of native language speakers with knowledge and background in motion systems is it possible to unlock the multilingual textual content and thus make it exploitable for the broad public. Furthermore the partners of different countries support the translation of common parts of metadata and in this way the project fulfils an objective of Europeana that includes availability of content for the users all over Europe. Additionally, the arrangement of the partners in different European countries has further advantages which have to be taken into account. Personal contacts as well as native language and social aptitudes ease a lot of tasks defined within the project, e.g., implementation of the dissemination plan, country specific adaptations of IPR contracts (and especially explanations for the authors), better contact to local user groups (important for adequate usability tests and collection of feedback) etc. The vision of thinkMOTION is to satisfy the thirst for scientific knowledge and technical curiosity for lifelong learning both for professionals and laypersons, independent of age and qualification. Due to the lack of resources especially in small and medium sized enterprises, it is hard for them to follow the latest scientific advances - it is often limited to the national level. This is supported by the fact that international and European conferences in this area take place almost without industrial participation, leading to an increasing estrangement between industrial, commercial users and scientific research facilities (e.g., IFToMM World Congress, bi-annual Design Society Congress). thinkMOTION closes the gap between science, industry, knowledge and education by using powerful database-technologies and metadata-based descriptions of mechanisms. Therefore the thinkMOTION library is also a valuable catalogue of design solutions and provides all necessary tools to understand and evaluate a suggested mechanism and adopt its characteristic kinematic to the desired application. Supporting dimensional analysis, the digital library also provides interactive sources like digital books, free software tools or interactive work sheets to teach and to perform necessary work steps for graphical or numerical synthesis-methods, Corves et al. [7]. The integrated mechanism search module provides a structured search form, where the motion task can be described explicitly with controlled, partially icon-based vocabulary. For easy use the search form is divided into structural and motion related criteria (Fig. 7). After submitting the query formulated within the selected search form, a sorted list of mechanisms is generated, displaying all mechanisms matching the specified criteria (Fig.  8). This list can be sorted by choosing different schemes. For each search result a thumbnail image, a brief functional description and the most essential topological information are displayed in tabular format. Each mechanism can be selected and examined in detail in a separate window. Due to the large amount of existing motion tasks, the mechanism database often provides a principle solution, which realizes a desired motion and is the base for methods and techniques for dimensional synthesis.

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Fig. 7  Mechanism search form

Conclusion and Outlook DMG-Lib and its European future project thinkMOTION represent an open access technical online library providing enriched knowledge in the domain of mechanism and machine science. The approach of the project members, to convey expert knowledge and establish a community for professionals and interested laymen, is suitable to be integrated into classical design methodology. For engineering designers it is valuable to find multiple principle solutions for a given motion task using an expert search tool, which processes the database of mechanism descriptions. Additionally basic knowledge and further synthesis methods in the field of mechanism science are provided as a one-stop source for design engineers. A further aim is the direct support of IFToMM activities. This includes the implementation of a web-based tool for the Permanent Commission for Standardization of Terminology in MMS, which allows a more productive workflow of the Commission, Brix et al. [11]. The content of the IFToMM dictionary is also an important factor in managing the utilization of knowledge in a multilingual environment.

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Fig. 8  Mechanism search result (excerpt of complete list)

The objective is to establish thinkMOTION as a central content platform for the IFToMM. This implies the collection of IFToMM publications, indexing for multilingual searching and linking to other knowledge collected in thinkMOTION.

References 1. Brix, T., Döring, U., Corves, B., Modler, K.H.: DMG-Lib: the digital mechanism and gear library – Project. In: Proceedings of the 12th World Congress in Mechanism and Machine Science, Besancon, 18–21 June 2007

[AU2]

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2. Kerle, H., Corves, B., Mauersberger, K., Modler, K.-H.: Zur Entwicklungsgeschichte der Getriebemodelle – Über die technikgeschichtliche Bedeutung der Getriebe-Prototypen. In: 8. Kolloquium Getriebetechnik Aachen 2009, pp. S.3–S.14. Verlagshaus Mainz, Aachen (2009). ISBN: 3-86130-984-X 3. Hüsing, M., Choi, S.-W., Corves, B.: Cabriolet-Verdeckmechanismen eröffnen neue Perspektiven. In: Konstruktion 55. 6:S.37–S.43 (2003) 4. Corves, B., Kloppenburg, J.: History and future of the IGM-mechanism collection. History of Machines and Mechanisms 2006. In: IFToMM Workshop Lectures, Ithaca, 9–10 Sept 2006 5. Rasmussen, E.: Information retrieval challenges for digital libraries. In: Proceedings of the 7th International Conference on Asian Digital Libraries (ICADL’04), Shanghai, pp. 93–103. Springer, New York, 13–17 Dec 2004 (2005) 6. Döring, U., Brix, T., Reeßing, M.: Application of computational kinematics in the digital mechanism and gear library DMG-Lib. Special issue on CK2005. In: International Workshop on Computational Kinematics. Mech. Mach. Theor. 41(8):1003–1015, Aug 2006 7. Corves, B., Niemeyer, J., Kloppenburg, J.: IGM-mechanism encyclopedia and the digital mechanism library as a knowledge base in mechanism theory. In: Proceedings of DETC2006: ASME 2006. International Design Engineering Technical Conference and Computers and Information in Engineering Conference in English, Philadelphia, 10–13 Sept 2006 8. Mayhew, D.J.: The Usability Engineering Lifecycle – A Practitioner’s Handbook for User Interface Design. Morgan Kaufmann, San Francisco (1999) 9. Purday, J.: Europeana v1.0, Annual Report, 1 Feb 2009 – 31 Jan 2010 10. Ceccarelli, M. (ed.): Distinguished Figures in Mechanism and Machine Science. Springer, Dordrecht (2007) 11. Brix, T., Döring, U., Corves, B.: Suggestion for a more productive workflow and infrastructure of the PC for Standardization of Terminology. In: 23 rd Working Meeting of the IFToMM PC for Standardization of Terminology on MMS. Minsk-Homel, Belorussia, 21–26 June 2010 12. IFToMM statues: http://130.15.85.212/const/statutes.html, (2010)

Micromachines: The Role of the Mechanisms Community G.K. Ananthasuresh

Abstract  Micromachines is a mature field today, although it is usually known by other names in various parts of the world. We briefly review the genesis of this field and how mechanisms researchers became involved. The successes of the field are many and have led to creation of a number of commercial products. This success is partly due to mechanisms research but more significantly due to rapid developments in microfabrication technology. We discuss the influence of the limitations of microfabrication techniques on the mechanisms used in this field. Interestingly, the strategies that were developed for overcoming these limitations have extended the scope of mechanisms and machines and are influencing technologies beyond the realm of micromachines. Many challenges lie ahead and multi-disciplinary approaches combined with mechanisms techniques will prove to be beneficial in the coming years.

Introduction Micromachines, as the name implies, ought to be about machines with micron dimensions. The term “micromachines” was popular in Japan and it meant miniaturization of existing things. The enormous success of microelectronics and the ensuing ever-decreasing size of electronic consumer products might have been partly responsible for coining this term. With a lot of effort, one can perhaps miniaturize just about anything including a car with all its moving parts. But this type of miniaturization does not always make sense, not only for economic reasons but also due to performance related issues. When the International Federation for the promotion of Mechanism and Machine Science (IFToMM) chose this term for its technical committee—the TC on Micromachines under the founding G.K. Ananthasuresh (*) Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560012, India e-mail: [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_12, © Springer Science+Business Media B.V. 2011

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Chair, Professor T. Hayashi in 1994—it was perhaps because of the prominence of the word “machines” in this phrase. By that time, the other parts of the world were using other names: microelectromechanical systems (MEMS) and microsystems technology (MST). North American countries embraced the term MEMS while European counties preferred MST. For a while, MEMS seemed to be the term adopted by most of the world but today there is a gradual move towards what can be called simply microsystems. What was more important than the term used to describe this important field was the philosophy of miniaturization that gradually developed in the late 1980s and matured rapidly in the years that followed. This has to do with an emphasis on seamless integration of mechanical elements with electronics. It also meant that instead of assembling mechanical and electronic elements into a system, as it is done at the macro scale, the two elements had to be made using similar processes on the same substrate. ‘Substrate’ is a term used in the semiconductor industry to refer to the base material used. A silicon wafer is a substrate. Sometimes, it could be glass. Today it can also be a polymer or a ceramic. Silicon processing, owing to its enormous success in very large scale integration (VLSI) technology, seemed a natural choice for making such integrated microelectromechanical entities. A few academic laboratories (e.g., at Stanford University [1]) and industries (e.g., Westinghouse [2, 3]) in the United States of America began to research this field as early as the late 1960s. Professor Angell’s laboratory at Stanford University developed, arguably, the first micromachined accelerometer [1] while Westinghouse investigated the possibilities of making light valves with movable mirrors [3]. This trend of making sensors and actuators, which is still sustained today, emerged at the outset in this field. A few other attempts were made to make systems with micron dimensions [4, 5] but the real impetus for the field came when movable linkages and motors were reported in 1986–1987 [6–10]. Fan, Tai, and Muller [10] developed in-plane joints, a four-bar linkage, and an electrostatic micromotor using polycrystalline silicon. They used a new process known as surface micromachining to make assembled jointed mechanisms without assembly. The key to this process was the sacrificial or fugitive layer that held the structures in place until the last step when this layer was dissolved to release the movable structures. Figure 1 illustrates the process of realizing a hinge using surface micromachining. The section-view of the early electrostatic motor is shown in Fig. 2. Other groups, notably Massachusetts Institute of Technology (Cambridge, USA) [7] and Bell Laboratories [8] were also successful in realizing movable mechanical components that can be batch-fabricated using silicon-based processes. Not only in-plane revolute joints but also out-of-plane joints can be made without assembly [11]. Intricate gear trains, racks, chain drives, etc., were also realized by developing suitable micromachining processes in silicon [12]. Cams and other higher kinematic pairs were also used in micromachines [13]. Recently, spherical linkages were also realized using silicon machining [14]. Even though electrostatic motors, pin-joint, and linkages were largely responsible for the widespread ­attention

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Deposit a thin layer and pattern it. Substrate Deposit a thicker layer and pattern it.

Deposit another thin layer and pattern it.

Deposit a second thicker layer and pattern it.

Sacrifice thin layers to realize an assembled in-plane revolute joint without assembly.

Fig. 1  Cross-section views of the processing steps of surface micromachining with which an inplane hinge can be fabricated without assembly

Fig. 2  A section-view of the electrostatic micromotor that brought wide attention to the microsystems field in late 1980s

that the microsystems field received, especially from the mechanism community, these elements have not found much commercial use. There is a good reason for it—reliability. Friction and wear are quite severe at the micro scale and are found to be major causes for failure of micromachines. Thus, this field demanded novel ways to design mechanisms that do not involve joints in which parts rub against each other.

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Early Mechanisms Research in Microsystems Pioneers in the microsystems field were not researchers from the mechanisms and machines community. This was because this field evolved from the experts who knew microfabrication processes used to make integrated circuit (IC) chips. At the very outset, challenges began to appear in realizing movable silicon parts and making them reliable. Ingeniously conceived fabrication processes to make revolute and sliding joints were not sufficient because of the aforementioned reasons of friction and wear and ensuing failure. Another problem with joints is that the clearances are bad in micromachining processed that make released mechanical members with joints. Researchers, therefore, sought alternate techniques for realizing deterministic motion without using joints. Many novel designs were conceived. One of them is the folded-beam suspension used in an electrostatic comb-drive [9]. It is a clever substitute for a sliding joint. Shown in Fig. 3a is a schematic of a compliant slider that has no joints and has single-piece construction. It has now become an integral part of many useful micro devices including some commercial products. See Fig. 3b for one of its uses in a linear actuator. The compliant slider consists of slender beams arranged such that the floating plate has low translational stiffness in one in-plane direction but very high translational stiffness in the other in-plane direction and high rotational stiffness about the out-of-plane direction. This was the point when mechanisms researchers entered the field to offer novel solutions. Professor A. Pisano of University of California, Berkeley, reviewed some basic mechanisms that one could use in micromachines [15]. Out of necessity, instead of using jointed rigid-body mechanisms, there was a widespread development of flexible beam-based mechanism configurations in micromachines. They came known to be compliant micromechanisms [16, 17].

Fig. 3  (a) A compliant slider that can move vertically, (b) the compliant slider used in an electrostatic translational actuator (Courtesy: Sandia National Laboratories, USA)

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Challenges and Opportunities Compliant designs in microsystems came about as a necessity but have proven to be useful at large sizes too. Another important consequence is that mechanisms researchers began to work in related areas such as solid mechanics. This is because kinematics in compliant mechanisms is intrinsically tied to deformation mechanics. Even though traditionally kinematics does not deal with the cause for motion, that notion is not adequate when one begins to work with compliant mechanisms. This has indeed led to innovative kinematic models where torsional springs are included at the joints. Two such examples are the pseudo rigid model [18] and the springleverage model [19]. Micromechanical components are actuated using a variety of transduction principles. Electrostatic, electromagnet-based, thermal, piezoelectric, etc., are commonly used. Because of the tight coupling among these energy domains, both modelling and design offer new challenges and opportunities in mechanisms research. Dynamics is also part of this activity. Hence, mechanisms and machine science research assumes new facets in micromachines technology. Materials also play a significant role in micromachines research. Silicon has been the choice material for micromachines until now. Single crystalline silicon is anisotropic. It is also essentially brittle. Care must be taken in designing deformable structures using silicon. A lot of other materials including polycrystalline silicon, silicon dioxide, silicon nitride, silicon carbide, metals, etc., are also used. Lately, ceramic and polymers (polydimethyl siloxane and SU8) are also used. A number of issues related to material properties and interface issues become important. Microfabrication processes continue to play a major role in micromachines. As the new materials, especially the active or smart materials, are increasingly coming into the realm of micromachines, new opportunities and challenges are faced by micromechanics researchers. Electronics and control aspects too are important. Microrobotics is another related field where all the aforementioned issues come together. Surgical tools, biomedical diagnostic devices, micro air vehicles, autonomous mobile micro devices—all come under micromachines extending its scope outside the traditional mechanisms field while retaining the fundamental roots in kinematics and mechanics. A major limitation of micromachines is that they remain primarily planar or stacked thin structures. Truly three-dimensional motion remains elusive. The problem lies in microfabrication techniques. But some also question why spatial motion is necessary. There are a few specialized micro devices that have three-dimensional motion capabilities. But much needs to be done in this regard. This is surely a challenge that is best addressed by the mechanisms and machines community. Micromechanical tools play an important role in biological studies today. The displacements and forces of micromachines match those experienced by biological cells. Hence, one has access to the “workshops” of the biological world. Mechanical response is emerging as a new biomarker. In this domain too, mechanisms of various levels of sophistication from simple micro-grippers to complex tools that can manipulate the biological molecules are under development today.

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All the applications and related areas mentioned in this section make one thing clear: that the mechanisms community is well poised to diversify into other areas while holding ground in its strength. It opens up avenues for multi-disciplinary research. Such collaborative activities enrich other fields as a by-product of enriching the core mechanisms field.

The Role of the Professional Organizations A number of professional organizations such as Institute of Electrical and Electronic Engineers (IEEE) and American Society of Mechanical Engineers (ASME), in addition to IFToMM, have contributed much to the microsystems field. Soon after the microsystems field began to attain an identity as an emerging field, special sessions, tutorials, and invited talks were organized in mechanisms conferences. IEEE and ASME created special committees and task forces to initiate activities in this field within their own community. IFToMM too created its Technical Committee on Micromachines in 1994, not too long after the field came into existence. In recent times, dedicated workshops were also organized in the area of micromachines by IFToMM. It will be beneficial if these efforts are further catalyzed by increased participation from other technical committees of IFToMM given the multi-disciplinary nature of micromachines research.

Conclusions Micromachines is a field initiated by mostly electronics engineers and specialists in microfabrication techniques. Mechanisms researchers entered the field to develop new techniques for joint-less mechanisms that relied upon elastic deformation. This paved the way for contributions by mechanisms researchers in numerous ways in the microsystems field. Some of these are microsensor and microactuator development, precision machines [20], micro robotics, tools for micromanipulation and micro surgery, mechanical characterization of biological cells, etc. IEEE, ASME, IFToMM, and other professional organization realized the importance of this field at its inception and nurtured it well. There are many challenges left as new and active materials have begun to appear. It is fair to conclude that, when mechanisms researchers work in the area of micromachines, a singular emphasis on kinematics or dynamics is not sufficient; one needs to take a holistic view of a machine by considering materials, manufacturing, control, reliability, and other issues all at once. It certainly enriches the mechanisms and machine science community when problems in the micromachines field are addressed. Acknowledgements  The author thanks Professor Marco Ceccarelli without whose encouragement and understanding, this article would not have been written.

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References 1. Roylance, L.M., Angell, J.B.: A batch-fabricated silicon accelerometer. IEEE Trans. Electron Devices ED 26, 1911–1979 (1979) 2. Nathanson, H.C., Newell, W.E., Wickstrom, R.A., Davis, J.R.: The resonant gate transistor. IEEE Trans. Electron Devices ED 14(3), 117–133 (1967) 3. Guldberg, J., Nathanson, H.C., Balthis, D.L., Jensen, A.S.: An aluminum/SiO3 silicon on Sapphire light valve for projection displays. Appl. Phys. Lett. 26, 391 (1975) 4. Angell, J.B., Terry, S.C., Barth, P.W.: Silicon micromechanical devices. Sci. Am. 248, 44–55 (1983) 5. Petersen, K.E.: Silicon as a mechanical material. Proc. IEEE 70(5), 20–457 (1982) 6. Fan, L.-S., Tai, Y.-C., Muller, R.S.: IC-processed electrostatic micro-motors. IEEE International Electron Devices Meeting, San Francisco, pp. 666–669 (1988) 7. Mehregany, M., Bart, S.F., Tavrow, L.S., Lang, J.H., Senturia, S.D., Schlecht, M.F.: A study of three microfabricated variable-capacitance motors. In: Proceedings of Transducers 1989. The 5th International Conference on Solid-state Sensors and Actuators and Eurosensors III, pp. 173–179 (1990) 8. Gabriel, K.J., Trimmer, W.S.N., Mehregany, M.: Micro gears and turbines etched from silicon. In: Transducers 1987, Tokyo, pp. 853–857 (1987) 9. Tang, W.C., Nguyen, T.-C., Howe, R.T.: Laterally driven polysilicon resonant microstructures. In: Proceedings of IEEE Micro Electro Mechanical Systems, Salt Lake City, pp. 53–59 (1989) 10. Fan, L.-S., Tai, Y.-C., Muller, R.S.: Integrated movable micromechanical structures for sensors and actuators. IEEE Trans. Electron Devices 35(6), 724–730 (1988) 11. Pister, K.S.J., Judy, M.W., Burgett, S.R., Fearing, R.S.: Microfabricated hinges. Sens. Actuat. A 33, 249–256 (1992) 12. Sandia National Laboratories Microelectromechanical Systems: www.mems.sandia.gov 13. Ananthasuresh, G.K.: Cams in microelectromechanical systems, chapter 15. In: Rothbart, H. (ed.) Cam Design Handbook, pp. 505–527. McGraw-Hill, New York (2003) 14. Lusk, C.P., Howell, L.L.: Components, building blocks, and demonstrations of spherical mechanisms in microelectromechanical systems. ASME J. Mech. Des. 130(3), 034503–1– 034503–4 (2008) 15. Pisano, A.P.: Resonant-structure micromotors: historical perspective. Sens. Actuat. 20, 83–89 (1989) 16. Kota, S., Ananthasuresh, G.K., Crary, S.B., Wise, K.D.: Design and fabrication of microelectromechanical systems. J. Mech. Des. Trans. ASME 116(4), 1081–1088 (1994) 17. Ananthasuresh, G.K., Howell, L.L.: Mechanical design of compliant microsystems: a perspective and prospects. J. Mech. Des. 127(4), 736–738 (2005) 18. Howell, L.L., Midha, A., Norton, T.W.: Evaluation of equivalent spring stiffness for use in a pseudo-rigid-body model of large-deflection compliant mechanisms. J. Mech. Des. Trans. ASME 118, 126–131 (1996) 19. Krishnan, G., Ananthasuresh, G.K.: A systematic method for the objective evaluation and selection of compliant displacement amplifying mechanisms for sensor applications. J. Mech. Des. 130(10), 102304 (2008): 1–9 20. Chen, S.-C., Culpepper, M.L.: Design of a six-axis micro-scale nanopositioner-mHexFlex. Precis. Eng. 30, 314–324 (2006)

Role of MMS and IFToMM in Multibody Dynamics Javier Cuadrado, Jose Escalona, Werner Schiehlen, and Robert Seifried

Abstract  An important application of multibody dynamics is mechanism theory. Rigid and flexible bodies are widely applied for modeling of planar and spatial machines, for their dynamical analysis with respect to motion and strength, vibration and control, and for their optimization. Interacting machine parts result in a variety of contact problems. Some fundamentals and typical mechanism and machine problems will be presented.

Introduction The historical evolution of multibody dynamics has been reviewed by Schiehlen [1] and Shabana [2]. Multibody system dynamics is related to classical and analytical mechanics. The most simple element of a multibody system is a free particle already introduced by Newton while the essential element, the rigid body, was defined by Euler. The equations obtained using the free body principle are known in multibody dynamics as Newton-Euler equations. D’Alembert and Lagrange considered systems of constrained rigid bodies. Lagrange’s equations of the first kind represent differential-algebraical equations (DAE) while the second kind leads to a minimal set of ordinary differential equations (ODE).

J. Cuadrado (*) University of La Coruña, Ferrol, Spain e-mail: [email protected] J. Escalona Escuela de Ingenieros, Dept. Ingeniería Mecánica y de los Materiales, University of Seville, Camino de los Descubrimientos s\n, 41092 Seville, Spain W. Schiehlen and R. Seifried University of Stuttgart, Stuttgart, Germany M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_13, © Springer Science+Business Media B.V. 2011

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Mechanism theory deals with constrained mechanical systems. However, the application of the powerful graphical methods developed in the early twentieth century by Wittenbauer was restricted to planar mechanisms. Later, in 1955 matrix methods were introduced by Denavit and Hartenberg for spatial kinematics, which formed the basis for the dynamical analysis of spatial linkages first published by Uicker [3]. The first international symposium on multibody dynamics was sponsored by the International Union of Theoretical and Applied Mechanics (IUTAM) and organized by Magnus in Munich, Germany, in 1977 (Magnus [4]). The second symposium jointly sponsored by IUTAM and IFToMM took place in Udine, Italy (Bianchi and Schiehlen [5]). Since then, many works on multibody dynamics have been presented at IFToMM conferences and symposia, and published in the IFToMM journal Mechanism and Machine Theory. In 2005, IFToMM established a Technical Committee (TC) for Multibody Dynamics to promote the activities of the international multibody community and to serve as a communication channel among its members. The TC focuses its activity on the following three aspects: coordination and support of multibody dynamics conferences, publication of selected papers from conferences in multibody dynamics journals, maintenance of a web page on multibody dynamics (www.iftomm-multibody.org). Recently, the TC has been a key element in the creation of a new series of conferences: the Joint International Conference on Multibody System Dynamics (IMSD), the first world-level event on multibody system dynamics, whose first edition was held on May 25–27, 2010 in Lappeenranta, Finland, co-chaired by Mikkola and Schiehlen. Now the achievements in rigid and flexible multibody dynamics as well as contact problems are reviewed and the influence of the discipline on MMS is described.

Rigid Body Dynamics The elements of multibody systems for machine modeling include rigid bodies which may also degenerate to particles, coupling elements like springs, dampers or force controlled actuators as well as ideal, i.e. inflexible, kinematical connecting elements like joints, bearings and motion controlled actuators. The coupling and connection elements, respectively, are generating internal forces and torques between the bodies of the system or external forces with respect to the environment. Both of them are considered as massless elements. Real mechanisms and machines are mainly subject to holonomic constraints which may be given by geometrical or integrable kinematical conditions. Their description is the task of kinematics. The position variables representing translation or orientation, respectively, of the p free disassembled bodies i read with respect to the inertial frame I as

ri = ri (x ), SIi (t ) ≡ Si (t ) = Si (x ), i = 1,2,..., p

(1)

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where x(t) means the vector of 6p dependent coordinates. By assembling the system, q constraints are added, given explicitly or implicitly, respectively, by

x = x (y , t ) or Φ (x ) = 0

(2)

where y(t) means the vector of the f = 6p-q independent or generalized coordinates. The second derivative results in the translational and rotational acceleration ∂v i ∂v y + i T ∂t ∂y ∂w ∂w i a i (t ) = w i (t ) = J Ri (y , t ) y + Ti y + ∂t ∂y

ai (t ) = v i (t ) = J Ti (y , t ) y+

(3)

where the velocity vectors and the Jacobian matrices J Ti and J Ri appear. Dynamics deals with the origin of motion, the forces and torques. Starting from the 6p Newton-Euler equations

 + k (x, x ) = q ( e ) (x, x ) − Φ Tx λ Mx

(4)

According to D’Alembert’s principle, one gets the minimal number of f ordinary differential equations by left pre-multiplication with the transposed f × 6p-Jacobian matrix J T , also denoted as equations of motion

M (y, t ) y(t ) + k (y, y , t ) = q (y, y , t )

(5)

representing an ordinary system of differential equations (ODE). Machines and mechanisms have usually a large number of joints or constraints, respectively, resulting in a small number of degrees of freedom and highly nonlinear equations of motion. The joint forces and torques are required as the dynamical loads q(r) for evaluation of the durability of the connecting elements following from Eqs. 4 and 5 as

T T q( r ) =  E − MJ( J M J)−1 J  ( k − q( e ) )  

(6)

The generation of equations of motion for multibody systems is a nontrivial task requiring numerous steps during evaluation of the fundamental relations. Beginning with the space age in the middle of the 1960s and establishment of machine and mechanism science (MMS), the generation of equations of motion was more formalized. The resulting formalisms were used for the development of computer codes for multibody systems: they are the basis of computational multibody dynamics. Twenty-five years later, there were known 20 formalisms described in the Multibody System Handbook, Schiehlen [6]. Many of them are still used today.

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For time integration of holonomic systems, the inertia matrix in Eq. 5 has to be inverted, which is numerically costly if a system has many degrees of freedom like a robot,

 y(t ) = M −1 (y, t )q (y, y , t )− k (y, y , t )

(7)

Recursive algorithms avoid this matrix inversion. A fundamental requirement, however, is a chain or tree topology of the multibody system. For systems with closed loops, such as four-bar mechanisms, the loop may be opened and the corresponding constraint added. Then, a differential-algebraic system of equations (DAE) is obtained. The given set of nonlinear differential equations (7) can be solved by numerical time integration. However, the effort of numerical simulations is always large due to the complexity of the machines and mechanisms. Thus, the proper choice of integration methods is very important. Nevertheless, it is not possible to give general recommendations since, on the one hand, new integration methods are mostly developed by numerical mathematicians and, on the other hand, the performance of computers is increasing continuously. Often, the engineer applies an integration method at hand and performs test runs with decreasing error tolerances to see whether the solution converges to the correct one.

Flexible Multibody Dynamics A multibody system is considered as flexible if it contains bodies that deform at the time they experience large rotations and translations. In this section, the three most common approaches used in multibody dynamics for the description of deformable bodies, namely the floating frame of reference approach (FFR) (Shabana [7]), the large rotation vector formulation (LRV) (Geradin and Cardona [8]) and the absolute nodal coordinate formulation (ANC) (Shabana [9]), are briefly outlined. The FFR formulation is the natural extension of the dynamics of rigid multibody systems to the analysis of systems that include deformable bodies. Its application is restricted to small deformation problems, although the substructuring technique enables extension to large deformation cases. Finite element nonlinear formulations can also be applied to the dynamics of deformable bodies that undergo large reference motion. The most used finite element approaches in multibody dynamics are the LRV formulation and the ANC formulation. They are not as computationally efficient as the FFR approach, but they can be applied to large deformation problems. In the following paragraphs the three formulations are described using a flexible beam as a deformable body, because many deformable multibody systems can be modeled with finite element beams. In the FFR formulation the position of a point P that belongs to a flexible body, as shown in Fig. 1, is given by:

r P = R + S (θ )(u 0 + u f )

(8)

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Fig. 1  Kinematic description of a deformable body

where u f = Nq f , R and q are the reference coordinates that describe the position and orientation of the body frame with respect to the global frame , q f is the vector of elastic coordinates, and N is the shape function matrix used to describe the deformation vector u f in the body frame. N is a function of the undeformed position vector u 0 . In this approach, the displacement vector is defined in a moving frame and it is a linear function of the elastic coordinates. Due to this fact, the inertia forces obtained with this formulation are highly non-linear functions of the coordinates, but the elastic forces are in many cases linear functions of the elastic coordinates q f . The shape functions included in matrix N are static and/or dynamic deformation modes that can be analytical functions, or obtained using the finite element method. In both cases, the reference conditions, which define the attachment of the body frame to the flexible body, are considered as the boundary conditions of a linear structural problem whose solution provides the deformation shape functions. There are many methods (Kim and Haug [10]) for selection of an adequate combination of shape functions. In the finite element nonlinear formulations described here, the separation into reference motion and deformation displacement is not considered. In both formulations, the position of a point of the deformable body is a function of the finite element nodal coordinates. In the LRV formulation (also known as Cosserat rod or geometrically exact beam) the position of a point P is obtained as:

r P = r (x ) + S s (x )u0

(9)

where u 0 = [0 u h ]. The position of a point on the beam centerline r and the orientation of the cross section frame Ss are interpolated as functions of the beam longitudinal parameter x. Different orientation coordinates (Euler angles, director cosines or Euler parameters) have been used in the literature to construct Ss as a function of x. The interpolation of them is not a trivial task (Romero [11]). In most implementations of this formulation, the beam cross section is assumed to be rigid. Parameters u and h are the coordinates of point P within the crosssection.

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In the ANC formulation the position of a point P is obtained as:

r P = Ne

(10)

where N is the shape function matrix that is a function of the parameters x, u and h that are the coordinates of the point in the undeformed configuration, and e is the vector of nodal coordinates. While the nodal coordinates in the LRV method include absolute position vectors and any family of rotational coordinates, vector e contains absolute position vectors and slopes, which are partial derivatives of the position vectors with respect to the body parameters. The main differences between these two formulations are that the ANC formulation does not include rotation coordinates as nodal degrees of freedom and the cross section is assumed to be deformable. In both formulations the inertia forces are simpler functions of the coordinates than in the FFR approach, being completely linear in the case of the ANC formulation but, on the contrary, elastic forces are non-linear functions of the nodal coordinates even in the case of linear elastic bodies. Current research in the FFR approach include a search for new methods to account for the geometric stiffening (Lugris et  al. [12]) and the foreshortening effects that require consideration of second-order terms in the strain–displacement relationship. An adequate selection of deformation shape functions for particular applications, and methods to simplify the inertia forces, are also open problems. In the LRV method, the cross section can take any angle with respect to the beam centerline. In some applications, it is convenient to model Euler-Bernouilli beams in which the cross-section remains perpendicular to the beam cross-section. In this formulation, the kinematic condition produces redundancy. This problem remains unsolved. The ANC formulation explained previously is the fully parameterized version of this method. The ANC formulation that was first presented (Escalona et al. [13]) used only the longitudinal parameter x as interpolation variable. In this case, the beam theory was used to obtain the elastic forces. The fully parameterized ANC formulation can show different locking problems and it may not give accurate results in case of small deformation problems. Some researchers try to solve these problems by returning to the line parameterized method (Schwab and Meijaard [14]). One important problem that appears in this case is that torsion in 3D beams cannot be described.

Contact Problems in Multibody Systems Contact and impact problems are common in many multibody system applications, in particular for machines and mechanisms, e.g. gear trains, electro-magnetic valves, hammer drills, vibration tables, robotic pick and place tasks, joints with clearance or during the human walking motion. The smooth global motion of a multibody system might be interrupted by collisions between moving bodies characterized by vanishing relative normal distance

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gn between the bodies, also denoted as unilateral constraint. Therefore, collision detection is fundamental in contact problems representing a non-trivial geometrical problem. In the case of a contact with non-zero relative velocity in the normal direction, g n , impact occurs and impact treatment is necessary. If after impact the relative velocity vanishes, a permanent contact remains. In both cases, during impact and contact, the equations of motion (4) have to be supplemented by the contact forces,

M (y, t ) y + k (y, y , t ) = q (y, y , t ) + w n Fn + w t Ft

(11)

Thereby, wn and wt project the normal contact force Fn and the tangential contact force Ft onto the directions of the generalized coordinates. The normal contact force prevents penetration of the colliding bodies, while the tangential contact force results from friction between the bodies. A detailed description based on unilateral constraints is given in Pfeiffer and Glocker [15]. In the following, some aspects of single frictionless contacts and impacts are briefly highlighted. During permanent contact of two bodies it is gn = 0, g n = 0 . Due to contact, only compressive forces Fn ≥ 0 can be transmitted. This is the major difference between unilateral contact and bilateral constraints, found in ideal joints, where also tensile forces can occur. In order to prevent penetration, also the normal acceleration must be nonnegative. If the contact opens it is gn > 0 and the contact force vanishes. Thus at each time point the contact yields the complementarity condition,

Fn ≥ 0, gn ≥ 0, Fn gn = 0

(12)

Combining Eqs. 11 and 12 yields a linear complementarity problem, which must be solved for the contact force and system states. Impacts, as a special type of contact, have recently attracted much attention in rigid multibody dynamics. The global motion of multibody systems occurs on a slow time scale characterized by low frequencies. In contrast an impact is a high frequency phenomenon of very short duration, which requires a fast time scale. During impact, usually kinetic energy of the rigid body motion is lost. Impacts can initiate wave propagation in the bodies which absorb parts of the kinetic energy. The waves propagate in the bodies until they vanish due to material damping. During impact also high stresses might occur near the impact point, which may result in plastic deformation also contributing to the kinetic energy loss. Macromechanically, these various sources of kinetic energy loss during impact are often summarized and expressed by a coefficient of restitution. For multibody systems, two approaches of impact modeling are often used: the instantaneous impact modeling and the continuous impact modeling. The first one is based on classical impact theory known for rigid bodies and unilateral constraints. Thereby the impact duration is assumed to be infinitesimal where the velocities jump and the position remains unchanged. The impact computation, i.e. the change of velocity, occurs on velocity/impulse level, where the equation of motion is integrated over the infinitesimal impact duration. Then, the equation of motion on

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velocity/impulse level is combined with the kinematic coefficient of restitution, well-known as Newton’s hypothesis, or the kinetic coefficient of restitution, also referred to as Poissons’ hypothesis, see Pfeiffer and Glocker [15]. These event driven approaches require interruption of the time integration at each impact. An alternative approach for handling non-smooth dynamics are time-stepping methods, whereby the multibody system dynamics including unilateral constraints is discretized in time. For details see e.g. Glocker and Studer [16]. Using continuous impact modeling, the impact computation occurs on acceleration/force level. Thereby the impact is modeled as a short permanent contact and the “impact forces” are determined from a compliance force-law, which allows small penetration at the contact point, see e.g. Lankarani and Nikravesh [17]. In order to control the kinetic energy loss during impact, these force-laws are often combined with a coefficient of restitution. Different force-laws are summarized in Seifried et  al. [18]. Replacing the unilateral contact constraint, these continuous force-laws can also be used for describing permanent contact, such as in bearings with clearance as investigated by Flores and Ambrosio [19]. The impulsive approach is based on a coefficient of restitution, while the force approach may use it too. Traditionally, it is estimated from experience or measured by costly experiments. However, the coefficient of restitution may be determined by numerical simulations on a fast time scale resulting in a multi-scale simulation approach. Then, the multibody system simulation is supplemented by an additional simulation on the fast time scale, including all micromechanical elastodynamic and elasto-plastic effects, from which the coefficient of restitution can be evaluated as shown in Seifried et al. [18].

Mechanism and Machine Science Problems Multibody dynamics can be defined as computational mechanics of machines and mechanisms. In some ways, it represents the modern approach to the theory of machines and mechanisms, which makes use of numerical methods and computational tools to extract the best engineering results from the applied mechanics. A key aspect of this discipline is an efficient treatment of the kinematics of mechanisms with closed loops, a main hurdle which prevents classical mechanics from reaching the final and complete solution of kinematic and dynamic problems. The multibody approach defines the configuration of a mechanism with more coordinates than degrees of freedom, which means that m algebraic relations stand among the coordinates: such relations are called constraint equations, generally expressed as, Φ (x ) = 0 (13) where x are the dependent coordinates of the problem. The kinematic position problem implies solution of the nonlinear system of equations given by Eq. 13, with known values of the coordinates representing the degrees of freedom of the mechanism. This is usually done through the Newton–Raphson iterative method, which leads to the linearized form of Eq. 13 around some approximation x j to the solution,

Role of MMS and IFToMM in Multibody Dynamics



( )(

169

)

( )

Φ x x j x j +1 − x j = − Φ x j

(14)

where sub-index j indicates the iteration number. The iterative process is stopped when Eq. 13 is satisfied within some specified tolerance. Differentiating Eq. 13 with respect to time yields,

Φ x (x )x = 0



 (x, x )x Φ x (x ) x = −Φ x

(15)



(16)

which are the equations for the velocity and acceleration kinematic problems, both linear unlike the position problem. It must be noted that the dependent coordinates x used to define mechanisms in the multibody approach are usually related to specific families, i.e. relative, reference-point, and natural or fully Cartesian coordinates. For all three families, systematic procedures have been stated to obtain the corresponding constraints equations, which enable automatic generation of the constraints vector of Eq. 13 and, hence, automatic derivation of the velocity and acceleration equations (Eqs. 15 and 16), as explained in Garcia de Jalon and Bayo [20]. This means that the position, velocity and acceleration problems can be easily and systematically stated and solved through the multibody approach for any machine or mechanism, despite its complexity. Special attention must be paid to the Jacobian matrix of the constraints, Φ x , which appears in Eqs.  14 to 16, and plays a crucial role in the kinematics of machines and mechanisms. The null eigenvalues and associated eigenvectors of Φ Tx Φ x indicate the mechanism’s degrees of freedom and velocity fields associated to them, respectively, which can be helpful for the study of a mechanism’s mobility, singular and locking positions, workspace determination, and so on (Hernandez et al. [21]). An example of practical application of all these aspects is the kinematics of parallel manipulators, as in Fumagalli and Masarati [22]. The mentioned approach for the kinematics can find its applicability in the synthesis domain too. The described systematic procedure to state the kinematic relations at position, velocity and acceleration level, enables us to address the kinematic synthesis problem as an optimization problem (Sancibrian et al. [23]). The kinematic constraints gathered in Eq. 13 can be considered either as constraints of the optimization problem or as part of the objective function (or the objective function itself). With respect to the dynamics, the multibody approach always enables one to state the equations of motion, despite the mechanism’s complexity. If dependent coordinates have been used to define the mechanism, a basic form of the equations of motion is provided by the Lagrange equations of the first kind,

 + Φ Tx λ = Q Mx

(17)



Φ = 0

(18)

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with λ the vector of Lagrange multipliers, which contains the internal forces due to the constraints (Eqs.  4 and 2 are these same equations when reference-point coordinates are used to define the mechanism). Moreover, the above system of differential-algebraic equations (DAE) can be always reduced to a system of ordinary differential equations (ODE) in a minimum number of coordinates (as many as degrees of freedom of the mechanism), by carrying out a velocity transformation,

x = Jy

(19)

where y is the independent set of coordinates, and matrix J (which summarizes J Ti and J Ri from Eq. 3 for reference-point coordinates) is position dependent: its columns are obtained through successive velocity analyses with a unity value of the velocity of a certain degree of freedom and null value of the velocities of the remaining ones. Differentiation of Eq. 19 and substitution into Eq. 17 leads to an ODE as in Eq. 5,  = Q My (20) The equations of motion stated by any of the described procedures can be always integrated in time by numerical integrators, as explained in the second Section of this paper. Therefore, the multibody approach enables us to perform the forward dynamics analysis of any machine or mechanism, providing the resulting motion and reaction efforts in the joints (Korkealaakso et al. [24]). Furthermore, an inverse dynamics analysis, typically required for machine design, makes use of the same equations to provide the motor efforts that generate the prescribed motion, along with the reaction efforts in the joints (Fumagalli and Masarati [22]); however, in this case, Eqs. 17 and 20 become just algebraic equations. Finally, the general and nonlinear dynamic equations described may always be linearized in order to study vibration problems, as in Negrut and Ortiz [25], or Popp and Schiehlen [26]. Machine design is based on determination of the time-varying stress and strain fields in the different machine parts, upon which failure and durability criteria are applied. In this context, an attractive use of multibody dynamics consists of modeling as flexible those bodies of the mechanism whose design is being addressed. In this way, the coupled problem of large rigid-body motion and elastic deformation is solved, as explained in the third Section of this paper, and the histories of strains and stresses are obtained (Cuadrado et  al. [27]). For tribological problems, the contact techniques described in the fourth Section of the paper should be applied in order to provide the required stress and strain fields (Schiehlen et al. [28]). A practical application to railway of these concepts can be found in Kovalev et al. [29]. Recently, the power of multibody dynamics techniques is allowing us to develop detailed models of the most commonly used machine elements, which may help to provide better insight into the complex phenomena that take place within such elements than the traditional and simple models available in classical machine design books, while still being much more efficient than finite element techniques. Examples of this trend are the following: journal bearings (Flores et  al. [30]),

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c­ am-follower mechanisms (Fisette et al. [31]), meshing gears (Ziegler and Eberhard [32]), belt and pulley systems (Kerkkanen et al. [33]), and chain-sprocket mechanisms (Pedersen et al. [34]).

Conclusions Multibody dynamics may be understood as computational mechanics of machines and mechanisms. Started in the 1970s, it progressively gained maturity during the last three decades, and can be considered today as a well established discipline, which has yielded several commercial packages able to address real industrial problems. Multibody dynamics implies several steps, which can be carried out in a very general and systematic way: mobile mechanical systems can be modeled to the desired level of detail (rigid or flexible bodies, ideal or real joints, contact and impact between bodies), dynamic formulations state the equations of motion of the modeled systems, and numerical integrators allow one to solve them in time. The mentioned tools can be used to address the kinematic and dynamic analysis and synthesis of machines and mechanisms, no matter the level of complexity they have. Also, they are helpful for failure and durability analysis, and for the development of new detailed models of classical machine elements.

References 1. Schiehlen, W.: Multibody system dynamics: roots and perspectives. Multibody Sys. Dyn. 1, 149–188 (1997) 2. Shabana, A.A.: Flexible multibody dynamics: review of past and recent developments. Multibody Sys. Dyn. 1, 189–222 (1997) 3. Uicker, J.J.Jr.: On the dynamic analysis of spatial linkages using 4 by 4 matrices. Ph.D. thesis, Northwestern University, Evanston (1965) 4. Magnus, K. (ed.): Dynamics of Multibody Systems. Springer, Berlin (1978) 5. Bianchi, G., Schiehlen, W. (eds.): Dynamics of Multibody Systems. Springer, Berlin (1986) 6. Schiehlen, W. (ed.): Multibody Systems Handbook. Springer, Berlin (1990) 7. Shabana, A.A.: Dynamics of Multibody Systems. Cambridge University Press, New York (2005) 8. Geradin, M., Cardona, A.: Flexible Multibody Dynamics. A Finite Element Approach. Wiley, West Sussex (2000) 9. Shabana, A.A.: Computational Continuum Mechanics. Cambridge University Press, New York (2008) 10. Kim, S.S., Haug, E.J.: Selection of deformation modes for flexible multibody dynamics. Mech. Struct. Mach. 18, 565–586 (1990) 11. Romero, I.: The interpolation of rotations and its application to finite element models of geometrically exact rods. Comput. Mech. 34, 121–133 (2004) 12. Lugris, U., Naya, M.A., Perez, J.A., Cuadrado, J.: Implementation and efficiency of two geometric stiffening approaches. Multibody Sys. Dyn. 20, 147–161 (2008)

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13. Escalona, J.L., Hussien, A.H., Shabana, A.A.: Application of the absolute nodal co-ordinate formulation to multibody system dynamics. J. Sound Vib. 214, 833–851 (1998) 14. Schwab, A.L., Meijaard, J.P.: Comparison of three-dimensional flexible beam elements for dynamic analysis: classical finite element formulation and absolute nodal coordinate formulation. J. Comput. Nonlinear Dyn. 5, 011010-1 to 011010-10 (2010). doi:10.1115/1.4000320 15. Pfeiffer, F., Glocker, C.: Multibody Dynamics with Unilateral Contacts. Wiley, New York (1996) 16. Glocker, C., Studer, C.: Formulation and preparation for numerical evaluation of linear complementarity systems in dynamics. Multibody Sys. Dyn. 13, 447–463 (2005) 17. Lankarani, H., Nikravesh, P.: Continuous contact force models for impact analysis in multibody systems. Nonlinear Dyn. 5, 193–207 (1994) 18. Seifried, R., Schiehlen, W., Eberhard, P.: The role of the coefficient of restitution on impact problems in multibody dynamics. Proc. Inst. Mech. Eng. [K] J Multibody Dyn 224, 279–306 (2010) 19. Flores, P., Ambrosio, J.: Revolute joints with clearance in multibody systems. Comput. Struct. 82, 1359–1369 (2004) 20. Garcia de Jalon, J., Bayo, E.: Kinematic and Dynamic Simulation of Multibody Systems. Springer, New York (1994) 21. Hernandez, A., Altuzarra, O., Aviles, R., Petuya, V.: Kinematic analysis of mechanisms via a velocity equation based in a geometric matrix. Mech. Mach. Theor. 38, 1413–1429 (2003) 22. Fumagalli, A., Masarati, P.: Real-time inverse dynamics control of parallel manipulators using general-purpose multibody software. Multibody Sys. Dyn. 22, 47–68 (2009) 23. Sancibrian, R., Garcia, P., Viadero, F., Fernandez, A.: A general procedure based on exact gradient determination in dimensional synthesis of planar mechanisms. Mech. Mach. Theor. 41, 212–229 (2006) 24. Korkealaakso, P., Mikkola, A., Rouvinen, A.: Multi-body simulation approach for fault diagnosis of a reel. Proc. Inst. Mech. Engi. [K] J. Multibody Dyn. 220, 9–19 (2006) 25. Negrut, D., Ortiz, J.L.: A practical approach for the linearization of the constrained multibody dynamics equations. J. Comput. Nonlinear Dyn. 1, 230–239 (2006) 26. Popp, K., Schiehlen, W.: Ground Vehicle Dynamics. Springer, Berlin (2010) 27. Cuadrado, J., Gutierrez, R., Naya, M.A., Gonzalez, M.: Experimental validation of a flexible MBS dynamic formulation through comparison between measured and calculated stresses on a prototype car. Multibody Sys. Dyn. 11, 147–166 (2004) 28. Schiehlen, W., Seifried, R., Eberhard, P.: Elastoplastic phenomena in multibody impact dynamics. Comput. Meth. Appl. Mech. Eng. 195, 6874–6890 (2006) 29. Kovalev, R., Lysikov, N., Mikheev, G., Pogorelov, D., Simonov, V., Yazykov, V., Zakharov, S., Zharov, I., Goryacheva, I., Soshenkov, S., Torskaya, E.: Freight car models and their computer-aided dynamic analysis. Multibody Sys. Dyn. 22, 399–423 (2009) 30. Flores, P., Ambrosio, J., Claro, J.C.P., Lankarani, H.M., Koshy, C.S.: Lubricated revolute joints in rigid multibody systems. Nonlinear Dyn. 56, 277–295 (2009) 31. Fisette, P., Peterkenne, J.M., Vaneghem, B., Samin, J.C.: A multibody loop constraints approach for modelling cam/follower devices. Nonlinear Dyn. 22, 335–359 (2000) 32. Ziegler, P., Eberhard, P.: Simulative and experimental investigation of impacts on gear wheels. Comput. Meth. Appl. Mech. Eng. 197, 4653–4662 (2008) 33. Kerkkanen, K.S., Garcia-Vallejo, D., Mikkola, A.: Modeling of belt-drives using a large deformation finite element formulation. Nonlinear Dyn. 43, 239–256 (2006) 34. Pedersen, S.L., Hansen, J.M., Ambrosio, J.A.C.: A roller chain drive model including contact with guide-bars. Multibody Sys. Dyn. 12, 285–301 (2004)

State-of-the-Art and Trends of Development of Reliability of Machines and Mechanisms Irina V. Demiyanushko

Abstract  Today Reliability is a subject of increasing scientific interest and practical application with considerable multidisciplinary issues. A survey and basic problems are outlined with the aim to stress current significance of Reliability both in engineering and education frames. IFToMM role is also discussed as focused in the activity of the Technical Committee for Reliability.

Introduction The science of reliability of machines and mechanisms (MMS) has been developed rather recently – specifically, at the end of the twentieth century. Problems of reliability, which are applicable to all areas of engineering, first appeared as the most important consideration for machines and mechanisms (MM) of aerospace engineering, nuclear power, transport engineering, and the machine-tool industry. In some cases reliability criteria determined safety; in others, basically, it supported economy at all stages of life cycles of machines. There are many treatments and definitions of the concept of reliability that do not greatly differ among themselves; nevertheless, through 70–90 years of the past century, there have been many disputes over which schools of thought had the most credibility. Today a commonly accepted definition of reliability is as a property of certain objects (e.g., machines, mechanisms and their component parts), in which have been installed limits of values of all parameters that control the abilities of a particular object, that allows it to execute its required functions within these parameters, subject as well to other given exterior conditions such as maintenance, storage and transportation [1]. The following basic properties are included in any structure of reliability of machines: failure (refusal) detection, durability, resources, maintainability and I.V. Demiyanushko (*) Moscow Auto-Road, State Technical University (MADI), 64, Leningradskiy prospect, Moscow 125190, Russia e-mail: [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_14, © Springer Science+Business Media B.V. 2011

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c­ ontrol of maintenance. A succinct statement providing for reliability of machines was given by an academician of the Russian Academy of Science (RAS) Kuznetsov N.D. [2]: “Reliability of machines lies in the design stage, is ensured by the manufacturer and adequate testing and is supported by maintenance and repairs”. In a state-of-the-art treatment of reliability, one must distinguish between reliability of unique objects, reliability of objects with a small number of components and reliability of multi-component objects. Examples and methods of operation of a reliability theory differ for these different kinds of objects. One of the central concepts of a reliability theory is failure detection – an event that is in violation of a required state of the object. In a reliability theory, failure is treated as a random event, requiring as one of its basic control parameters a probability of no-failure during the given interval of time or within the limits of the given operating time. Resources and life cycle, being parameters of durability, also belong among the basic concepts of a reliability theory. Prediction of resources (lifetime) is a particularly important constituent of a reliability theory of machines and constructions. In an elementary situation, when an object operates up to first failure, the no-failure probability of the object simultaneously characterizes also its durability. The more common case, is when rate of failure is reduced to a minimum at the expense of technical diagnostic and maintenance operations that guarantee the warning of possible failures or at least their fast elimination without durable interruptions in maintenance and other undesirable after effects; these cases however can be surveyed. Under these conditions the important concepts become a boundary state, resources and life cycle duration.

A Historical Perspective Reliability theory in a state-of-the-art view arose during a 50 years period during the past century with the beginning of rapid development of electronics engineering and computer equipment. The reliability theory apparatus at that time was developed primarily with reference to systems whose elements interact among themselves from the point of view of storing function ability on a selection of logical circuits. The basic problem of a reliability theory consisted in an estimation of parameters of reliability of systems on known parameters of separate elements. Usually these elements were the result of a mass production that had been tested in quantity, sufficient for obtaining reliable statistical estimations of parameters of reliability. A distinctive feature of such objects, serving as an appendix to a reliability theory, was that conditions of their maintenance were uniform, stationary and susceptible to reproduction under conditions of bench tests. The reliability theory of such objects has been developed rather in detail. This theory became the constituent of the common theory of big systems: it usually was called a system reliability theory. Some development also resulted from a so-called parametric reliability theory in which failure was treated as an exit of parameters of objects for some established limits describing the function ability of those objects.

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Force and kinematic interactions of elements of MM have a more complicated character. The behavior of these objects essentially depends on their interacting with an environment, and also the character and intensity of processes of maintenance. For a prediction of behavior of MM components it is necessary to consider processes of deformation, chafing, accumulation of damages, cracking and destruction at certain variables, cyclical loads, temperatures and other external effects. For unique objects, machines and mechanisms of responsible destination reliability represents a strength concept, the term “strength reliability” is frequently used. For these objects, as already has been said above, extremely explicitly with usage of state-of-the-art methods of mechanics for a design stage and creation of machines are forecast parameters of reliability, first of all, parameters of durability, which further are checked and prove to be true during obligatory experimental inspections. While in service for unique machines of responsible destination the concept of resource on the state, based on methods of prediction of durability and methods of engineering preliminary tests is used. To judge parameters of no-failure operation and durability of objects as a whole, it is not enough to know only parameters of separate elements. Besides, for unique and small series machines we cannot calculate an accumulation of the statistical information on the basis of their bench or real tests as it is connected both to temporal expenditures, and with economic limitations. In this connection to prediction parameters of no-failure operation and durability of mechanical systems at design stages we apply basically calculation – theoretical methods, founded on statistical data on properties of materials, loads and effects. Therein lies the most essential difference of a reliability theory of machines, both from a system reliability theory, and from the parametric theory. The history of development of a reliability theory in the nineteenth century has been illustrated by Bolotin V.V. [1] with the help of the diagram shown on Fig. 1. The first elements of a reliability theory contained calculations of safety factors of elements of machines – relation of computational toughness (limit stresses, ­ultimate load) R to a computational operation load q and in a certain degree

Fig. 1  The diagram of a history of development of a reliability theory in the nineteenth century

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c­ haracterized its reliability level. The understanding of the statistical nature of safety factors came later – to the first third of the nineteenth century. In activities of Majer M. [3], Hotsialov N.F. [4] and Streletskiy N.S. [5], the performance of reliability P measured as probability of no overflow by the parameter of load q, the parameter of toughness R was introduced. In the second half of the nineteenth century the approach received further development in calculations of building constructions, when it was offered to introduce components of a safety factor, having given everyone some statistical sense, so there was a method of calculation on limiting states, which till now is used in calculations of building constructions. At the end of 50 years of the nineteenth century, the factor of time had been introduced into reliability theory. The point of view has by degrees gained recognition that failures and limiting condition of constructions should be treated as emission V (t) of some stochastic processes from admissible areas W. It is natural, that during the writing of this article we could not get rid of some tendentious representation about development of the theory and applied problems of reliability developed in Russia, though the general direction of works in all countries went in parallel and was determined by development of techniques and technologies. So representation about development of a science of reliability of MM in USA and GB can be found in works of Mahadevan [6], Meeker [7] Martin [8]. Up to this time the basic concepts of a system reliability theory have been created so there was a necessity for coordination of these basic concepts, their nomenclatures and their labels. The parametric reliability theory developed now, in effect, represents an attempt to introduce into calculations of reliability of big systems the analyses of physical mechanical phenomena, causing failures. Thus probability of no-failure P (R) becomes a functional of some stochastic process V (t), which characterizes modifications of parameters of a system in time. Thus, two different approaches to calculations on reliability are traversed (see Fig. 1). State-of-the-art methods of mechanics of materials and constructions with the help of computers allow producing calculations of machines on the basis of complicated computational schemes, maximum approximated to real conditions. Broad usage numerical methods – such as the Finite Element Method (FEM), a Method of Boundary Elements – were introduced, which with usage of state-of-the-art universal and specialized computational complexes (programs products) allow us to decide tasks of static and dynamic behavior of constructions at loads and the external effects varying in time, including temperature tasks and simulating of cracking processes. For example the advance reached to the present time in the field of simulation of complicated space systems of MM in view of abrasion, so allowing the solution of the task of dynamics of aviation gas-turbine engines rotors bearing in mind the friction in contact places [8]. To apply these achievements to prediction parameters of reliability, it is necessary to pass from determinates calculations to probability – statistical. In particular, in this direction have been practically solved and to the present time have been inserted into practice, methods of reliability prediction of aero-engines, gas turbine rotors [9] and other parts [10, 11] of these machines at statistical simulation of loads in flight cycles. The stress-strain condition of rotor constructions is analysed by FEM in view of nonlinear deformation,

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accumulation of faults, cracking and probabilistic performances of materials. The tendency of development of information technologies of design at maintenance of reliability with use of techniques of FEM for calculation of a statics, dynamics, linear and nonlinear behavior of objects has resulted in development of Stochastic Finite Element Analysis (SFEM) [12]. The experimental tools created to the present time and processing of the information they provide, allow us to quickly receive necessary information about behavior of structural materials and about the majority of the loads that are operational on our machines. Here new capabilities open state-of-the-art numerical methods and computer analyses. With respect to probabilistic – statistical prediction of parameters of reliability, the trend is toward usage of the method of statistical simulations (Monte Carlo), which allows us to produce estimations of parameters of stochastic processes and phenomena, giving us simultaneously an introduction to their possible and typical realizations in conditions of indeterminacy. In a reliability theory of mechanical systems, properties of materials and effects are adopted at random, therefore the behavior of objects also are random in character. Normative demands and specifications on maintenance superimpose certain limitations on these parameters. Limitations can be formulated as a condition of a determination of some random vector, object time-dependent and describing quality, in the given area.

The Fundamentals of a Statement of Reliability Estimate Problems The statement of problem of reliability prediction of complicated objects (the machine, the mechanisms, their elements) is reduced to definition of a probability of no-failure in time t * which is a random quantity P(t ) = prob.(t * > t ).



(1)

The density distribution function of failures at an instant t is f (t ) =

1 dN * , N 0 dt

(2)

where N0, N are the initial and given quantities of objects. The cumulative distribution function of time of failure occurrence is *



F (t ) = prob.(t * < t ) = 1 - P(t ).

(3)

Also it is connected to a density probability of failures t



F (t ) = ò f (t )dt. 0

(4)

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The rate of failure describing a density probability of failures in the proximal period if failure has not taken place yet and a density probability of failures are connected by a ratio l (t ) =

f (t ) . P (t )

(5)

The basic equation of reliability allows us to determine a probability of no-failure of the machine on a passing of rate of failure



t ïì ïü P(t ) = exp í - ò l (t )dt ý . îï 0 þï

(6)

Common methods of reliability prediction today are developed for different kinds of objects and types of failures. The development of methods of a reliability theory basically goes in the direction of consideration of the physical bases of failures (simulation of accumulation of damages and processes of crack propagation at a fatigue, a low-cycle fatigue, a creep, wear-fatigue, radiation damage, etc.), simulations of processes of loading of objects in time, accumulations of experimental data and simulations of properties of materials at different kinds of loading and complicated loadings, to development of methods of simulation of accumulation of failures and damages in conditions of indeterminacy. Complicated loading of objects at a simultaneous combination of different mode of failures, for example, durable toughness and a low-cycle fatigue that occurs in high-temperature details of mobile machines, reduction in necessity of development of multiparameter criteria for an estimation of probability of collapse (in this case – low-cycle crack initiation) P1, in particular, at low cycle loading [13]

P1 = prob.[σ R > σ q ; N R > N q ].



(7)

where sR and sq are limiting and operational stresses in the detail; NR and Nq are the limiting and operational numbers of cycles of loading of the detail. There is actually a problem on connection of probability of collapse and statistical safety factors of machine components. In this case Eq. 7, will be

P1 = prob.[kσ* < 1; k N* < 1],



(8)

kσ* kN* are statistical safety factors and cyclic lifetime with accepted significance level and confidence probability.

Actual Problems of MM-Reliability and Education Taking into account the discussion above it is obvious that, with engineering progress, emersion of new concepts of creation of MM, detection of new aspects of agencies of exposures and off loadings, the question of rationing of reliability of

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complex multilevel systems is actual.. In this direction the block diagrammes of reliability engaging structural flowcharts taking into account functional links and interacting of elements, graphical circuit designs in the form of trees of events and failures of installations, state graphs and transferring taking into account their statistical nature are explicated. Now the trend of application of methods of an artificial intellect – neural nets, illegible logic, etc. is tracked. These approaches are extremely practical for robots, representing an indicative instance of complex multilevel systems [14–16]. The reliability and resource prediction in maintenance remain as an important problem, when objects are exposed to continuous or selection check diagnostic tools. These methods of a reliability theory are directly connected to technical diagnostic methods, which development becomes one of the major conditions of a rise in reliability of machines in maintenance. Another, not less important, direction is the development of methods of optimal design in view of reliability criteria. Developments in the field of simulation of processes of loading, creation of numerical models of objects in view of their physical time behavior and accumulation of faults, and development of programming languages and the computational complexes, permitting us to pass to the parametric analysis of constructions, development of methods of a multi criteria optimization, allow us to hope for appearance of real solutions for creation of methods and systems of optimal multi criteria design in view of reliability factors. As a calculation founded on a probabilistic estimation, it is usually more correct than one that is conventionally determined: so units or details of objects can be designed with more compact levels of safety than with the determined design. These calculations are safety measures and/or more effective, as they allow reducing reserves and the mass of details thus is reduced, and loads are optimized. It is obvious that such design ensures not only reliability, but also safety. Certainly, still there is actually a problem of development of normative demands on reliability for different objects, first of all, responsible destination. Now parameters of reliability are already included in normative demands for air constructions, for objects of nuclear power, transport engineering etc. However, problems of reliability prediction and resources, development of methods and models for calculations of reliability of machines and mechanisms, accumulations of experimental data on materials and simulation of processes of a fault, experimental researches of behavior of constructions of machines at different loadings, development of methods and models for systems of optimal design, problems of preliminary treatment and prediction of resource in service time, remain the important scientific trends, requiring probes, creations and supports of appropriate scientific programs. There is a relevant question on creation of new university training courses in Reliability of MM. In particular, in connection with a progressive market economy transferring from state standards to regulations and standards of corporations, representations about definition of parameters of an operational reliability considerably vary. Emersion of unique installations of complex multilevel systems also demands creation from students of new representations about reliability, safety and risks.

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In summary it is necessary to pay attention to direct communication of a problem of reliability of objects with a probability of originating technogeneous catastrophes. The analysis of saturation of potentially dangerous and technical complicated objects in the technogeneous sphere of all industrially developed countries point to a risk that increase of number and weight of consequence of recent technogeneous catastrophes is subject to the exponential law [17]. It is obvious that the rise of reliability and decrease of risks of technogeneous emergencies and catastrophes, as connected tasks, should be considered jointly. This demands special investigations, and it is necessary to take into account that the degree of the calculation – experimental substantiation of heavy emergencies and catastrophes has sharply decreased on a measure of growth of risks [17]. In this direction, investigations are basically carried out on results of particular cases; at the same time, in joint developments of reliability prediction and prediction of risks of originating extreme situations with a technogeneous character, essential promotion is planned, basically, for unique objects. At the same time, for transport techniques (a road and transport complex), machine-building complexes, mining engineering, etc., the solution still lies ahead. Unconditionally, the major direction is development of training courses on MM reliability theory. Such courses are given at all leading technical universities of the world and textbooks and manuals continue to be published. An example is the textbook “The Statistical Mechanics and Reliability Theory” of Prof. V.A. Svetlitskiy in MSTU of Bauman in Moscow [18].

IFToMM Influence in MM-Reliability Developments IFToMM pays much attention to support of the trends discussed above. The Technical Committee on Reliability of machines and mechanisms (TCR IFToMM) was created in 1997. A significant role in shaping the Committee, a statement of tasks and directions of its activity, was played by the National Academy of Science of Belarus with the participation of Prof. O. Berestnev. Scientific researches of scientists of Belarus in the field of reliability of machines, robots and mechanisms are presented in materials of the International Scientific and Technical Conference “Reliability of cars and technical systems”, October 2001гoдa, Minsk, in the book [19] and in a number of other publications. Since 2006, the chair-person of TCR IFToMM has been Prof. I. Demjanushko (Moscow State Automobile & Road University – MADI). TCR IFToMM carried out many activities promoting ideas of development of state-of-the-art trends of scientific investigations in the field of a reliability theory and the solution of applied problems with respect to ensuring reliability of machines, both unique objects and objects of mass production. Organization of active involvement in conferences by TMM members of the Committee, in particular, in the World Congresses on TMM, in international conferences RoManSy, international conferences on reliability in Minsk, Belarus, 2001, for the first time, a rigorous section on reliability of machines at the World Congress on TMM in Besancon, France; all these activities have

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drawn attention to the problem of reliability of machines and have allowed us to attract young scientists and students from different countries to participate in activities in these important areas. Well-known scientists from more than ten countries have taken part in the activity of the Committee, whose structure has been extended. During the last 2 years, members of the Committee have published more than 15 monographs and 30 articles, a significant amount of lectures have been given and new training courses have been developed. Activities of leading scientists both old and young have been published in recent years, including those presented in the Section of Reliability of IFToMM World Congress in Besancon, France, demonstrating that, in the majority of countries, the greatest attention in the field of reliability of MM is now being given in the following directions: • Construction of a system of reliability in projection of complex machines. In France, A. Hahnel M. Lemaire F. Rieuneau F. Petit, propose a framework for assessing and improving the reliability of machines and mechanisms. A multidisciplinary viewpoint is adopted to develop a reliability approach based on flexible representations that benefit from a comprehensive probabilistic and physical modeling of either the performance or the failure scenarios of the considered systems. They have suggested that FORM/SORM-based analysis yields traditional reliability measures. These results are exploited to contribute efficiently to design for reliability efforts. • Working out of the theory and methods of an estimation of parameters of reliability in the conditions of noncomplex information. A significant number of works in this area is presented by the scientific schools of China, where the approaches are based on developing Hybrid reliability models, such as Fuzzy event-precise probabilistic models and others. • Investigations in the area of methods and the equipment for diagnostics on a resource and reliability of unique objects, including use of methods of detection of imperfections and flaws (Reliability Analysis of 100MN Multi Way Die Forging Hydraulic Press’s Computer Control System – Zhongwei Liu and others, China; The Practice of Applying Acoustic Emission Phenomena for Nondestructive Control and Diagnosing of Technical State of Manufactured Articles – Royzman V. and others, Ukraina; Reliability and Safety of Rail Vehicle Electromechanical Systems – Vintr Z., Vintr M., Czech Republic). • The development of standard demands on reliability in various industries These investigations were carried out in an aircraft and gas turbine engine industry – [20, 21], in atomic engineering – [22–24], in the common engineering industry [19]. In atomic engineering, a member of PCR IFToMM, Prof. Tunc Aldemir, USA, carried out investigations into modeling of passive systems in nuclear power plants, such as pipes and structures for probabilistic risk assessment (PRA) using dynamic methodologies. Limitations in conventional PRA methodology using the event-tree/fault-tree approach constrain its value as an effective tool to address aging effects and quantify risk and reliability impacts of component aging management strategies.

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Conclusion In recent years there has appeared a significant amount of literature concerning reliability theory of machines. Numerous monographs and textbooks have been published; a wide variety of journals have included articles that deal with the subject; and many conferences have been held throughout the international scientific community. Nevertheless, success in forging a commonly accepted view of reliability theory of mechanisms and robots is still insufficient. In reality, there is not yet enough educational literature, there are relatively few reliability theory headings on the Internet that include mechanisms and robotics, etc. Some of the many difficulties that still remain in dealing with reliability problems for MM have been identified above in hope that more attention will be paid in the future.

References 1. Bolotin, V.V.: Prediction of a resource of machines and structures. M. Mech. Eng. (1984) 2. Kuznetsov, N.D.: Reliability of machines//Scientific bases of progressive techniques and technology. M. Mech. Eng. 1986, 87–97 (1993) 3. Majer, M.: Die Sicherkeit der Bauwerke and ihre Berechnung nach Grenzkraften anstatt nach zulassigen Spammungen. Springer, Berlin (1926) 4. Hotsialov, N.F.: Strengths coefficients. Build. Eng. (10) (1929) 5. Streletskiy, N.S.: Bases of the statistical account of safety factors of constructions. M. Stroyizdat (1947) 6. Haldar, A., Mahadevan, S.: Reliability and Statistical Methods in Engineering Design. Wiley, New York (2000) 7. Meeker, W.Q.: Trends in the statistical assessment of reliability. Department of Statistics and Center for Nondestructive Evaluation, Iowa State University, Ames (2010) 8. Martin, P.: A review of mechanical reliability. Proc. Inst. Mech. Eng. E: J. Process Mech. Eng. 212(E4), 281–287 (1998) 9. Pyhalov, A.A., Milov, A.E.: Contact’s problem in a FEM mathematical modeling of dynamic behavior of a rotor of turbo machines. Bull. IRSTU (5), 23–35 (2005) 10. Demiyanushko, I.V., Velikanova, N.P.: Forecasting of reliability and durability of disks of turbo machines. Bull. STU MADI 16–32 (2004) 11. Nognitskiy, Y.A. and others: Probalistic prediction of aviation engine critical parts lifetime, GT2006-91350. In: Proceeding of GT2006 ASME Turbo Expo, Barcelona (2006) 12. Haldar, A., Mahadevan, S.: Ames, Iowa 50010 Using Stochastic Finite Element Analysis, p. 344. Wiley, New York (2000) 13. Demiyanushko, I.V., Velikanova, N.P.: Probalistic assessment of the lifetime of thermal engines under thermo mechanical conditions. Modern problems of a resource of materials and designs, III-School-seminar, M. 69–74 (2009) 14. Berestneva, N.O.: Development of bases of the system approach at the analysis of reliability of complex multilevel technical systems, reliability of machines and technical systems. The international scientific and technical conference, Minsk, October 2001, pp. 91–92 (2001) 15. Riving, E.I.: Mechanical Design of Robots, p. 328. McGraw-Hill, New York (1988) 16. SRI International: Robot Design Handbook. Andeen, G.B. (ed. in-Chief), pp. 329. ­McGraw-Hill, New York (1988) 17. Makhutov, N.A.: Forecasting of risks of occurrence of extreme situations character. Reliability of machines and technical systems. The international scientific and technical conference, Minsk, October 2001, pp. 91–92 (2001)

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18. Svetletskiy, V.A.: The statistical mechanics and reliability theory, P.h. of MSTU of Bauman, M. pp. 503 (2004) 19. Berestnev, O., Soliterman, U., Goman, A.: Rationing of Reliability of Technical Systems, p. 265. INDMash, Minsk (2004) 20. Nozhnitsky, Y.A., Lokshtanov, E.A, Dolgopolov, L.N., Shashurin, G.V., Volkov, M.E., Tsykunov, N.V., Ganelin, I.I.: Probabilistic prediction of aviation engine critical parts lifetime, GT2006-91350. In: Proceedings of GT2006 ASME Turbo Expo: Power for Land, Sea and Air. 8–11 May 2006, Barcelona (2006) 21. Aвиaциoнныe пpaвилa Чacть 33. Hopмы лeтнoй гoднocти двигaтeлeй вoздушныx cудoв. MAК (2004) 22. Margolin, B.Z., Gulenko, A.G., Nikolaev, V.A., Ryadkov, L.N.: A new engineering method for prediction of the fracture toughness temperature dependence for RPV steels. Int. J. Pres. Ves. Piping 80, 817–829 (2003) 23. Norms of strength analysis of the equipment and pipelines of atomic power installations. PNAE Г-7-002-86, M, ENERGOATOMIZDAT, pp. 525 (1989) 24. Aldemir, T., Siu, N.O., Mosleh, A.: Reliability and Safety Assessment of Dynamic Process Systems. NATO Asi Series. Series F: Computer and Systems Sciences, vol. 120

Role of MMS and IFToMM in Robotics and Mechatronics I.-Ming Chen

Abstract  Robotics and mechatronics are multi-disciplinary subjects sharing some common fundamental knowledge and technical development. This article briefly outlines areas of works in robotics and mechatronics respectively, and explains the commonalities and differences of the two subjects. The roles of MMS in the robotics and mechatronics are explained and reflected in the current IFToMM events. With the merger of IFToMM Technical Committee on Robotics and Technical Committee on Mechatronics, this article also points out the missions and topics of the newly established Technical Committee on Robotics and Mechatronics (TC R & M) and its future role in the larger Robotics and Mechatronics community.

Introduction A robot is a machine able to extract information from its environment and use knowledge about its world to move safely in a meaningful and purposeful manner. It is also a system that exists in the physical world and autonomously senses its environment and acts in the world. Robotics is the engineering science and technology of robots, and their design, manufacture, application, and structural disposition. Thus, robotics is a multidisciplinary subject involving mechanics, electrical and electronic engineering, computer engineering, and more recently biology, zoology, physiology and even neuron sciences. From the composition of a robot system, one can find that the key enabling technology of robotics encompasses structural and locomotion mechanisms, actuators, sensors, vision, power supply, computing and communication units, intelligence and cognitive ability. Contrary to robotics starting off as the study of a new category of machines with intelligence and active degrees of freedom to react, Mechatronics is coined as the I.-M. Chen (*) School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore 639798, Singapore e-mail: [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_15, © Springer Science+Business Media B.V. 2011

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synergistic combination of Mechanical engineering, Electronic engineering, Computer engineering, Control engineering, and Systems Design engineering to create, design, and manufacture products to make possible the generation of simpler, more economical, reliable and versatile systems. French standard NF E 01-010 gives the following definition for Mechatronics: “approach aiming at the synergistic integration of mechanics, electronics, control theory, and computer science within product design and manufacturing, in order to improve and/or optimize its functionality”. Thus, the results of mechatronics research are used mostly in existing commercial products like automobiles, electronics appliances, everyday equipment and advanced complex systems like airplanes, spaceships, and medical equipment. From the above description, it is very obvious that the commonality of Robotics and Mechatronics is in the sharing of fundamental knowledge in mechanical, electrical, control, and computer engineering, and many key technologies, such as actuators, sensors, vision, and embedded computing and communication units. Integration of the engineering subjects becomes an essential part of training and education of robotic and mechatronic engineers. Through the integration and use of common technology, one can design and build complex intelligent engineering systems to cope with sophisticated operating environments. However, to distinguish the difference between Robotics and Mechatronics, the easiest way is to examine the final product obtained from the research result. Normally robotics research will end up with new types of machines with multiple degrees of freedom movement capability – be it industrial manipulators, mobile robots used in the hospital or at home, medical surgical robots, or space robots on the space shuttle and space station. Mechatronics research normally will create technologies or components embedded in the existing products by giving them new capabilities, for example, an anti-lock brake system in automobiles, servo-control system in machining centers, hard-disk drive control systems, CD/DVD reader head pick-up system, medical imaging system, etc. In other words, Robotics integrates multi-disciplinary knowledge to create new machines and products (which may bear being called a “robot”), whereas Mechatronics embeds multi-disciplinary knowledge in new components and algorithms in existing products (which normally are not called a “robot”). Of course, with different types of final products, specific components and algorithms/methods, and the overall system design approaches are also different in robotic and mechatronic systems. For example, navigation and localization algorithms for mobile robots are seldom used in a mechatronic product; machine vision used in automated manufacturing lines is very different from the 3D robot vision on a mobile robot.

Role of MMS in Robotics and Mechatronics According to IFToMM PC on Standardization of Terminology, Machine and Mechanism Science (MMS) is a branch of science, which deals with the theory and practice of the geometry, motion, dynamics and control of: machines, mechanisms

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and mechanism elements and systems thereof, together with their application in industry and other contexts. MMS is a crucial element in both Robotics and Mechatronics because MMS provides the basic knowledge and technology knowhow of building robots and mechatronics systems in terms of their structure design, mechanics, and actuation, and control. Recognizing this critical role in robotics, the First CISM-IFToMM Symposium on Theory and Practice of Robots and Manipulators (ROMANSY) was held on Sept. 5–8, 1973, in Udine, Italy, not long after IFToMM had been founded in 1969. The first ROMANSY, or Ro.Man.Sy., as the Symposium used to be referred to, marks the beginning of a long-lasting partnership between two international institutions, CISM, the Centre International des Sciences Mécaniques and IFToMM, the International Federation for the Promotion of Mechanism and Machine Science. The aim of ROMANSY is to bring together researchers from the broad range of disciplines included in robotics, in an intimate, collegial and stimulating environment and to share their visions of the evolution of the robotics disciplines and identifying new directions in which these disciplines are foreseen to develop. The most recent event was the 18th edition of ROMANSY successfully held on July 5–8, 2010 in Udine, Italy (www.romansy2010.org) (Fig. 1). The role of MMS in Robotics research can be reflected in the paper topics of ROMANSY: • • • •

novel robot design and robot modules/components; service, education, medical, space, welfare and rescue robots; humanoid robots, bio-robotics, multi-robot, embodied multi-agent systems; challenges in control, modeling, kinematical and dynamical analysis of robotic systems; • innovations in sensor systems for robots and perception; • recent advances in robotics.

Fig. 1  ROMANSY 2010 in Udine, Italy

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Fig. 2  ISRM 2009 in Hanoi, Vietnam

For people interested in knowing more about the history of ROMANSY symposia, please refer to the website: http://cism-iftomm-romansy.org/history/html/previous_ symposia.htm (Fig. 2). Likewise, according to the definition stated in IFToMM Terminology, Mechatronics includes works in actuators, sensors, control and monitoring of machines. MMS provides the fundamental design principle for actuators and sensors, and modeling of the mechanical systems for control and monitoring purposes. Intelligent control, Intelligent structures, adaptive machines all require the fundamental system modeling tools provided by MMS. Because mechatronics research supports a very large industrial basis worldwide, IFToMM started a new event - IFToMM International Symposium on Robotics and Mechatronics (ISRM) on September 21–23, 2009 in Hanoi, Vietnam. The idea is to create a new series of international symposia with emphasis on the common knowledge in mechatronics and robotics for industrial relevance. It is open to researchers worldwide in mechatronics and robotics more relevant to industrial applications. The first edition of ISRM was successfully held in the Hanoi University of Technology with more than 60 delegates from 13 countries. The paper topics in ISRM also reflect the importance of MMS in Mechatronics: • • • • • •

micro-systems – MEMS; machine vision; parallel mechanisms and PKM; mobile systems; drives and actuators; control;

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• mechanisms; • robot design in medicine and rehabilitation; • mechatronics education. In summary, the roles of MMS in Robotics and Mechatronics are well reflected in the TC sponsored major events: ROMANSY and ISRM. The two events are held in alternating years mainly in Europe and Asia with topics complimentary to each other in order to optimize conference participation and intellectual exchange.

Mission and Topics of TC Robotics and Mechatronics The establishment of a Technical Committee on Robotics and Mechatronics marks a new milestone in IFToMM history. The new TC aims to promote and strengthen the common research and development in disciplines like mechanics, component design, electronics, control, information processing and software development for robotics and mechatronics, and at the same time, to explore existing and niche applications with social and industrial relevance, such as green technology, new energy, and sustainable technology development. The topics of the Technical Committee on Robotics and Mechatronics shall cover the study of the fundamental disciplines in Robotics and Mechatronics as well as key technology areas in MMS context, such as • • • • • • •

design of robot systems and robot modules/components; design of mechatronics systems as embedded solutions; control, modeling, kinematics and dynamics of mechanical systems; actuators and sensors; perception and vision for intelligent systems; bio-mechatronics and bio-robotics; application system development for industry, transportation, service, education, medicine, space, welfare and rescue purposes; • new theory and practices for robotics and mechatronics in niche areas such as energy, environment, and sustainability. Recognizing the spirit of the IFToMM Constitution as well as individualism for research excellence, the new TC will take a balanced approach to reach out to both IFToMM and non-IFToMM communities to increase the awareness of IFToMM and the TC events. As of August 2010, the new TC became the largest one among all IFToMM TCs with 66 members from 26 of the 44 IFToMM Member Organizations (MO). The TC will recruit more new members from MOs that do not have any representative in the TC as well as promoting the individual observers from existing MOs to participate in the TC and IFToMM events. Currently TC R&M sponsors three other international and regional events in addition to ROMANSY and ISRM: International Workshop on Robotics in AlpeAdria-Danube Region (RAAD), International Symposium on Multi-body Systems and Mechatronics (MUSME), and International Conference on Mechatronics

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Technology (ICMT). Thus, the members in the new TC will have many opportunities to become actively involved in the organization and setting the topics of the events. Lastly, the new TC also has an active role in education and training for robotics and mechatronics. The concept of Summer School to be proposed and organized by TC R&M members could be new TC events to serve this purpose. The idea of Summer School is to bring together a number of reputable international experts to give lectures on new and specific topics in robotics and mechatronics to young prospect graduate students as well as industrial professionals in a short period of time (3–5 days). The students will be able develop close interaction with the lecturers and among themselves. In this way, IFToMM’s educational mission can be fulfilled.

Conclusion This article briefly outlines the commonality and differences between Robotics and Mechatronics. The roles of MMS in Robotics and Mechatronics are exemplified according to the topics presented in IFToMM related events like ROMANSY and ISRM. Finally, the aims and topics of the newly established IFToMM TC Robotics and Mechatronics after the merger of the two individual former TCs are elaborated. The new activities and prospect of new TC education events are described. It is hoped that with a balanced approach, the TC will be able to play a critical role in shaping the R&D, and education front of Robotics and Mechatronics in the near future. Acknowledgements  The author would like to acknowledge Professors Bodo Heimann and Shinichi Yokota for their leadership as Chairmen of the former IFToMM TC Robotics and TC Mechatronics respectively.

Role of MMS and IFToMM in the Creation of Novel Automotive Transmissions and Hybrids Madhusudan Raghavan

Abstract  Over the past few decades, mechanism and machine science has helped lay a very solid foundation for the topological representation of mechanisms and linkages. This has allowed the sorting and classification of industrial devices and machinery based on topological structure. This has been most useful for developing a sound understanding of the possible mechanism-based solutions for a given engineering problem. It has also allowed the exploration of novel solutions wherein an understanding of the degrees-of-freedom necessary to accomplish a particular set of functions has guided the search for new devices. In the present offering, we describe the use of this approach for the creation of novel gear schemes for automotive transmissions and hybrid drive units.

Introduction Graph theory has been used elegantly for the classification of mechanisms for a specified application. The classic paper by Freudenstein and Maki [1] shows how to represent a link as a graph vertex and a joint as a graph edge with a label. This approach strips the linkage of its dimensional information and enables one to focus on the essential connectivities that define its characteristics. Having accomplished this, one can then enumerate all other graphs that represent alternative linkages or mechanisms having similar characteristics as the one of original interest. Maki and Freudenstein demonstrate this process of “systematic enumeration/innovation” in

M. Raghavan (*) Hybrid Systems, Propulsion Systems Research Lab, GM R&D Center, 30500 Mound Road, Warren, MI 48090-9055, USA and  6816 Trailview Court, West Bloomfield, MI 48322, USA e-mail: [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_16, © Springer Science+Business Media B.V. 2011

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the context of 6-bar and 8-bar linkages that could serve as automotive engine mechanisms with variable stroke and compression ratio. Hsieh and Tsai [2] extended this concept to geared linkages with the intent of application to automotive transmissions. They used a three-step process wherein they first estimated the overall speed ratio without specifying dimensions, then compared various possible speed ratios and finally, systematically enumerated all possible clutching sequences. In the present work we show how we have adapted Tsai’s approach to complex geartrains comprised of planetary gearsets and clutches. This approach has yielded hundreds of novel transmission arrangements and in particular has led to practical designs that have gone into very high volume production world-wide. A vehicle transmission delivers mechanical power from an engine to the drive system, such as fixed final drive gearing, axles and wheels. A mechanical transmission allows some freedom in engine operation, usually through alternate selection of five or six different drive ratios, a neutral selection that allows the engine to operate accessories with the vehicle stationary, and clutches or a torque converter for smooth transitions between driving ratios and to start the vehicle from rest with the engine turning. Transmission gear selection typically allows power from the engine to be delivered to the rest of the drive system with a ratio of torque multiplication/reduction and with a reverse ratio. An electrically-variable transmission (EVT) is a mechanical transmission augmented by one or more electric motor/generators. This is currently a popular approach to “hybridizing” a vehicle. A motor/generator is a device, which uses battery power to apply a torque on a transmission member (in motor mode), or generates power for storage in the battery, while serving as a speed-controlled brake (in generator mode). Typically, an EVT uses differential gearing to send a fraction of its transmitted power through a pair of motor/generators. The remainder of its power flows through another, parallel path that is all mechanical and direct, of fixed ratio, or alternatively selectable. One form of differential gearing is the well-known planetary gear set with the advantages of compactness and different torque and speed ratios among the various members of the gear set. The battery or other device allows engine starting with the transmission system and regenerative vehicle braking, as appropriate.

Prior Work on Transmission and EVTs Much of the understanding of multi-speed transmission kinematic operation has been described in the language of lever diagrams [3]. Since the automobile industry is generally moving in the direction of larger numbers of fixed speed ratios we briefly review recent work on multi-speed transmissions. Haka [4] proposes a design with three planetary gear sets. One gear set is a dedicated gear set in that one of the planetary members (reaction member) is permanently connected to a stationary member and another is continually connected to the input drive member.

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The dedicated planetary gear set can be arranged to provide either an underdrive or an overdrive depending on the input and reaction members. The resulting design has at least seven forward drive ratios and one reverse drive ratio. Borgerson et al. [5] present the design of a six-speed transmission having an input shaft connectable with an engine and planetary gear unit. A single carrier supports pinions from adjacent planes of gears. Stevenson [6] presents a seven-speed concept with three planetary gear sets. The second and third planetaries are connected. The design has six torque transmitting mechanisms, engaged in sets of two to get seven forward speeds and one reverse speed ratio. Wittkopp [7] proposes a three planetary design with three brakes, three clutches, and three fixed interconnections between the gear sets. We also briefly review some recent offerings in the EVT literature. Malikopoulos et al. [8], describes the development of an Integrated Starter Alternator (ISA) for a High Mobility Multi-Purpose Wheeled Vehicle. Its primary purpose is to provide electric power for additional accessories but it can also be used for mild hybridization of the powertrain. Pagerit et al. [9] study several vehicle platform and powertrain configurations to assess the sensitivity of fuel economy to mass variation. Their conclusion is that conventional and parallel hybrid configurations are the most sensitive while fuel cell-based arrangements are the least sensitive. Suppes [10] argues that closed-system regenerative fuel cells (RFCs) are an alternative to non-regenerative fuel cells as a transition technology and mainstay of a hydrogen economy. He suggests that substantially petroleum-free automobiles can evolve from hybrid electric vehicles as fuel cell prices decrease. Tamai et al. [11], review the essential features of the hybrid system for the 2007 Model Year Saturn VUE Green Line Hybrid SUV. This concept provides the fuel economy of a compact sedan while delivering improved acceleration performance over the base vehicle. The VUE’s hybrid functionality includes: engine stop-start, regenerative braking, intelligent charge control of the hybrid battery, electric power assist, and electrically motored creep. An example of a highly successful EVT concept developed at GM is the tworange, input-split and compound-split electrically variable transmission now produced for transit buses and SUVs. This EVT was invented by Schmidt [12]. One embodiment of this idea employs three planetary gear sets coaxially aligned. The two motor/generator sets are also coaxially aligned with the planetary gear sets. Gear members of the first and second planetary gear set are respectively connected to the two motor/generators. Their carriers are operatively connected to the output member. Today’s typical single-mode systems rely on much larger electric motors than are needed in the patent-protected two-mode system. The two-mode system innovations provide performance and fuel economy improvements at highway speeds and better trailer towing ability. Packaging is more efficient than today’s single mode designs as the system’s compact and powerful electric motors are designed to fit within the approximate space of a conventional automatic transmission. This system reduces fuel consumption at highway speeds much more effectively than available single mode systems and achieves at least a 25% improvement in composite fuel economy in full-size truck applications.

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Generation of New Concepts The steps of the process are described in detail by Raghavan et al. [13]. They may be summarized as follows. We make an upfront decision regarding the number of planetary gear sets and clutches to be used in the proposed transmission. For example, we may choose to investigate designs with three planetary gear sets and six or seven friction elements in a quest for eight-speed transmission mechanisms. We enumerate all possible kinematic combinations of these elements that could potentially serve as legitimate transmission mechanisms. To do this we utilize the transmission governing equations to identify specific configurations that yield viable eight-speed designs. We then select candidates that satisfy additional requirements, such as ratio spread, step ratios, reverse-to-first ratios, single-transition shifts, etc. There are several details to be followed in the above procedure. First we must decide on whether the input to the transmission is fixed to one of the transmission members or clutched to it. We must also decide on how many clutches/brakes we engage at any given speed ratio, as this would determine the number of constraints on the system. Typically, we select a scheme with the maximum possible number of speed ratios. This involves some combinatorics calculations. Next, we decide on the number and type of fixed interconnections between various members of the planetary gear sets. An edge-vertex representation of transmission mechanisms is most useful in this step, as it allows the sorting of designs based on graph theory [14, 15]. These decisions serve to focus our search into specific “families” of transmission mechanisms. After that, we formulate algebraic representations of the various transmission candidates, using equations to describe all of the applicable constraints, such as clutches, brakes, etc. The key enabling concepts that make this synthesis procedure work are: algebraic representation of geared kinematic systems, topological representations of mechanisms and graph isomorphism, generalized lever diagrams, which allow unified code generation and computational efficiencies, fast numerical methods to rapidly search large multi-dimensional design spaces.

The Generalized Lever It is worth taking a moment to understand the concept of the generalized lever. The basic lever used in traditional transmission analysis is shown in Fig. 1. It shows how we go from a planetary gear set to a three-node graph representation or lever, which may be used for rudimentary graphical velocity and torque analysis as illustrated in Fig. 2. Details are in Raghavan et al. [16] but the main takeaway is that if we use the mappings listed in Table 1, we may use the same lever equation to represent all possible permutations of the nodes of the lever. This effectively allows us to cycle through all topological variants of a given design as we evaluate and assess

Role of MMS and IFToMM in the Creation of Novel Automotive Transmissions and Hybrids

Fig. 1  Graph and lever representation of planetary gear set Fig. 2  The use of levers for velocity analysis

Table 1  Mappings of the standard lever equation Standard lever equation Mapping New lever equation 1  1 z = 1 +  y − x  a a

a→a

1  1 z = 1 +  y − x  a a

1 a

1  1 x = 1 +  y − z  a a

a→

a→− a→ −

a 1 + ( a)

1  1 z = 1 +  x − y  a a

1

1  1 y = 1 +  x − z  a a

(1 + a )

a→ − (1 + a ) a→ −

(1 + a ) a

1  1 y = 1 +  z − x  a a 1  1 x = 1 +  z − y  a a

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candidates from a functional perspective. This approach yields several orders of magnitude improvements in computational efficiency when we are tasked with evaluating thousands of arrangements for complex multi-speed transmission applications.

EVT Hybrid Functional Operating Modes The functional requirements for EVTs may be grouped into several operating modes. The first operating mode is the “battery reverse mode” in which the engine is off and the transmission element connected to the engine is not controlled by engine torque, though there may be some residual torque due to the rotational inertia of the engine. The EVT is driven by one of the motor/generators using energy from the battery, causing the vehicle to move in reverse. The second operating mode is the “EVT reverse mode” in which the EVT is driven by the engine and by one of the motor/generators. The other motor/generator operates in generator mode and transfers 100% of the generated energy back to the driving motor. The net effect is to drive the vehicle in reverse. The third operating mode includes the “reverse and forward charging modes.” In this mode, the EVT is driven by the engine and one of the motor/generators. A selectable fraction of the energy generated in the generator unit is stored in the battery, with the remaining energy being transferred to the motor. The fourth operating mode is a “continuously variable transmission range mode” in which the EVT is driven by the engine as well as one of the motor/generators operating as a motor. The other motor/generator operates as a generator and transfers 100% of the generated energy back to the motor. The fifth operating mode includes the “fixed ratio” configurations in which the transmission operates like a conventional automatic transmission, with torque transfer mechanisms (clutches or brakes) engaged to create a discrete transmission ratio.

Graph Sorting The above concept generation/enumeration process produces a large amount of data which must be post-processed to find valid designs. This requires interpreting the data and drawing a sketch of the transmission cross-section. With potentially millions of designs, this can be a time consuming process. There are two issues: (1) a large number of the designs are not unique because the generalized method allows many representations of the same design; (2) many of the designs, while kinematically correct, are not topologically feasible. That is, when we attempt to sketch the 2-D transmission cross section we may find that there is no way to connect all of the elements (i.e., the gear sets, clutches, fixed interconnections

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and shafts) without interferences between connections. Several attempts may be necessary to determine that we have exhausted all of the potential ways to draw the cross-section before deciding that it is impossible and there is some uncertainty to the decision. To achieve the best efficiency in sketching designs, it would therefore be helpful to know a priori and with certainty whether or not a design is possible. Once we have our graph representation in hand for each synthesized design, we need to check the design for feasibility and uniqueness. As noted above, we only need to test that a graph is planar to decide whether or not the design is feasible. Fortunately, such a test (the Hopcroft-Tarjan algorithm [17]) exists and we use an implementation of it. Once feasibility is determined, we save the design and compare it to all remaining designs using a graph uniqueness (or isomorphism) test described by Tsai [18].

Prioritization Process To some extent key aspects of each powerflow have already been identified (e.g. overall ratio, ratio steps, element speed ratios) early in the process. Once these characteristics have been identified they can be used to initially quantify a powerflow’s merit. This allows the rough prioritization of candidate powerflows. This initial prioritization process does not typically identify a single superior candidate; rather several powerflows will have collectively similar results. At this point more detailed metrics can be developed that will further identify the merits of each of the top candidates. This type of data can be used to populate a “traffic light chart” (see Fig. 3) that will further refine the list of leading candidates. From the above chart it can be seen that PF A has the most desirable characteristics, but is not perfect. This approach can be applied to stepped ratio transmission, CVT’s and hybrid powertrains.

Powertrain Matching Power Flow Power Flow PF A PF B PF C PF AA PF AB

# of Spd

Top Gr

Top Step

OAR

5 6 5 6 5 6 7

0.53 0.69 0.49 0.64 0.51 0.6 0.64

1.23 1.23 1.38 1.24 1.23 1.18 1.15

5.4 5-6 5-6 6.22 5.39 6.67 7.5

Fig. 3  Traffic light chart

Risk Ratio Mechanic Progressi al Tech. on Level 3 1 1 3 3 3 3

Pack. Cost Fuel Econ.

Controls Tech. Level

Planes of Gears

2 2 1 3 2 2 3

2 3 2 3 2 2 3

Kinematic Cost Spin Loss Index Index Mesh Eff 17.5 19 22 19 15.5 18

4.8 4.6 11.7 8.84 6.7

98 98.85 98.3 96.7 98

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Fig. 4  Multi-speed concept 1

Results Two representative designs have been selected for presentation here out of a candidate pool of over 1,000 designs. The details of these two designs are as follows. 1. Multi-Speed Concept 1 (Fig.  4): This transmission (see Kao et  al. [19]), is a three-speed design that uses three simple planetary gear sets, two rotating clutches and three grounding clutches. There is one overdrive in this design. Features: All simple gear sets Two rotating input clutches Good ratio spread, torque ratios and steps Single transition clutching Direct drive It is worth noting that this particular arrangement has been adapted for a variety of high volume products such as the 6T40/45 series as well as the 6T70/75 series. 2. EVT Concept 1 (Fig. 5): This transmission (see Raghavan et al. [20]) is a fullfunction EVT comprised of three simple planetary gear sets, two rotating clutches, two stationary clutches, and two motor-generators, labeled MG1 and MG2.

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Fig. 5  EVT concept 1

It operates in Battery Reverse, EVT Reverse and Forward, Battery-charging Reverse and Forward, and has four fixed (i.e., all mechanical) speed-ratios. Features: All simple gear sets Acceptable pinion speeds Low electrical power losses Dual mode operation

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Role of IFToMM and MMS IFToMM has played a key role in the development and dissemination of the above theory and its applications. Prof. Ferdinand Freudenstein, one of the distinguished members of the US IFToMM organization, laid the foundations of the above graphbased search for alternative mechanizations in his landmark paper [1], cited earlier, as well as in numerous subsequent applications to other automotive sub-systems [21, 22]. Subsequently Prof. Lung-wen Tsai (also part of the IFToMM USA community) continued Prof. Freudenstein’s traditions via a series of profound papers on the application of graph-based enumeration techniques for various applications, particularly in the context of automotive transmissions [23], and novel robotic systems [24]. In more recent times, the IFToMM Transportation Machinery Technical Committee [25], has continued the application of these methods to various novel sub-systems including hybrid propulsion systems and battery electric vehicles, [26, 27]. The Committee holds quarterly teleconferences and has global participation from Russia, Korea, India, China, Taiwan, Australia, Greece, Germany, Slovakia, Finland, Poland and USA. This creates a vibrant environment for discussion, innovation and application. For example, the late Prof. Frolov’s team from Russia (now led by Prof. Alexander Kraynev of IMASH) has created numerous novel eight-speed transmission concepts using mixed planetary-layshaft arrangements. Similarly, Prof. Frank Park’s team at Seoul National University (IFToMM-Korea) is developing new methods to charge plug-in hybrid vehicles with minimal user-intervention. In India, Prof. Ashitava Ghosal’s team at the Indian Institute of Science, is creating novel low-cost hybrid propulsion architectures suitable for developing markets, with emphasis on small auxiliary power units, wheel motors, and belt-based CVTs. In China, Prof. Chengliang Yin’s team at Shanghai Jiaotong University, is developing novel control systems for battery-supercapacitor energy storage systems for hybrids [28]. In Australia, Prof. Nong Zhang’s team at the University of Technology Sydney, is evaluating new approaches to rapidly synthesize interior permanent magnet motors for hybrids without lengthy finite-element computations. It is our expectation that this forum will continue to result in novel methods and applications to enhance automotive and other sub-systems. In summary, in the present offering, we have shown how graph-based and algebraic synthesis procedures originating in mechanisms and machine science have been used to generate several thousand multi-speed transmission and EVT candidate designs for large volume automotive production. Sample concepts from the set generated are shown in this paper. The procedure allows the designer to generate and assess novel designs. It often proposes unusual arrangements, which even experienced designers might overlook. The process makes use of algebraic representation of transmission gear trains, graph-based searching and sorting, and transmission powerflow analyses. The computer-based procedure complements the traditional bag of tricks of the experienced transmission designer. Furthermore, as the requirements on fuel economy and performance compel manufacturers to use transmissions

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with higher numbers of speed ratios, designers have to tackle increasingly complex mechanisms. Another benefit is its ability to identify minimum- content designs, wherein the emphasis is on achieving the maximum level of functionality with the fewest components.

References 1. Freudenstein, F., Maki, E.R.: Creation of mechanisms according to kinematic structure and function. Environ. Plann. B 6(4), 375–391 (1979) 2. Hsieh, H.I., Tsai, L.: A methodology for enumeration of clutching sequences associated with epicyclic-type automatic transmission mechanisms. SAE Technical Paper (1996). doi: 10.4271/960719 3. Benford, H., Leising, M.: The lever analogy: a new tool in transmission analysis. Society of Automotive Engineers, Paper No. 810102 (1981) 4. Haka, R.: Multi-speed power transmission. US Patent 6,425,841, 30 July 2002 5. Borgerson, J., Maguire, J., Kienzle, K.: Transmission with long ring planetary gearset. US Patent 7,029,417, 18 Apr 2006 6. Stevenson, P.: Seven-speed transmission. US Patent 7,014,590, 21 Mar 2006 7. Wittkopp, S.: Seven-speed transmission. US Patent 6,910,986, 28 June 2005 8. Malikopoulos, A., Filipi, Z., Assanis, D.: Simulation of an Integrated Starter Alternator (ISA) system for the HMMWV. Society of Automotive Engineers, Paper No. 2006-01-0442 (2006) 9. Pagerit, S., Sharer, P., Rousseau, A.: Fuel economy sensitivity to vehicle mass for advanced vehicle powertrains. Society of Automotive Engineers, Paper No. 2006-01-0665 (2006) 10. Suppes, G.: Roles of plug-in hybrid electric vehicles in the transition to the hydrogen economy. Int. J. Hydrogen Energy 31, 353–360 (2006) 11. Tamai, G., Jeffers, M., Lo, C., Thurston, C., Tarnowsky, S., Poulos, S.: Development of the hybrid system for the Saturn VUE hybrid. SAE, Paper No. 2006-01-1502 (2006) 12. Schmidt, M.: Two-mode, compound-split electromechanical vehicular transmission. US Patent 5,931,757, 3 Aug 1999 13. Raghavan, M., Bucknor, N., Maguire, J., Hendrickson, J., Singh, T.: The design of advanced transmissions. Paper No. F2006P277, FISITA 2006, Yokohama (2006) 14. Chatterjee, G.,Tsai, L.W.: Enumeration of epicyclic-type automatic transmission gear trains. SAE 1994 Trans. 103(6), 1415–1426 (1995) 15. Chatterjee, G., Tsai, L.W.: Computer aided sketching of epicyclic-type automatic transmission gear trains. ASME J. Mech. Des. 118(3), 405–411 (1996) 16. Raghavan, M.: The analysis of planetary gear trains. ASME J. Mech. Robot. (2010) 17. Hopcroft, J., Tarjan, R.E.: Efficient planarity testing. J. ACM 21, 549–568 (1974) 18. Tsai, L.W.: An application of the linkage characteristic polynomial to the topological synthesis of epicyclic gear trains. ASME J. Mech. Transm. Autom. Des. 109, 329–336 (1987) 19. Kao, C-K., Usoro, P., Raghavan, M.: Six-speed planetary transmission mechanisms with two clutches and three brakes. US Patent 6,932,735, 23 Aug 2005 20. Raghavan, M., Bucknor, N., Hendrickson J.: Electrically variable transmission having three planetary gear sets and three fixed interconnections. US Patent 7,238,131, 3 July 2007 21. Vucina, D., Freudenstein, F.: An application of graph theory and nonlinear programming to the kinematic synthesis of mechanisms. Mech. Mach. Theory 26(6), 553–563 (1991) 22. Tsai, L-W., Freudenstein, F.: On the conceptual design of a novel class of Robot configurations. University of Maryland, Institute of Systems Research, Technical Report 1988–1950 (1988) 23. Tsai, L.-W.: Mechanism Design: Enumeration of Kinematic Structures According to Function. CRC, Boca Raton/London/New York/Washington, D.C. (2001)

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24. Lee, J.-J., Tsai, L.-W.: The structural synthesis of tendon-driven manipulators having a pseudotriangular structure matrix. Int. J. Rob. Res. 10(3), 255–262 (1991) 25. Link to IFToMM List of Officers and Member Organization Representatives: http://130.15.85.212/off/Officers.htm 26. Raghavan, M.: Efficient computational techniques for planetary gear train analysis. Proceedings of 12th IFToMM World Congress, Besancon, 18–21 June 2007, Paper No. 101 (2007) 27. Fenelon M.A.A., Furukawa T.: Next generation propulsion system architectures. In: Raghavan M., Bucknor N., Maguire J., Hendrickson J., Singh T. (eds.) Proceedings of NACOMM 2007, Bangalore, Paper 121 (2007) 28. Lei, W., Jianlong, Z., Chengliang, Y., Yong, Z., Zhiwei, W., Bucknor, N.: Realization and analysis of good fuel economy and kinetic performance of a low-cost hybrid vehicle for developing markets. Chin. J. Mech. Eng. (submitted)

Advancements and Future of Tribology from IFToMM Jianbin Luo

Abstract  A Tribology Committee, focused on tribology in machines, was set up in 2005 as a Technical committee of the IFToMM, an organization that has historically supported tribological activities. Tribology has been developed very rapidly in the last 20 years. Several new areas have been identified, such as nano-tribology, bio-tribology, superlubricity, and surface texture. In the present and following years, these topics as well as tribology in nanomanufacturing, green-tribology, tribology in extreme conditions, surface texture, and tribology in new energy fields will play important roles in the study of machines and mechanisms. We describe here some of the major advances in these areas in recent years and project some future needs in the next 10 years

Nano-Tribology Nanotribology, particularly nano-lubrication and nano-friction has been a very hot area in the past 20 years. In nano-lubrication, the research has been mainly focused on lubrication in a nano-gap, i.e. the transition from EHL to boundary lubrication, which was one of the main problems in the lubrication theory system in the 1990s. Thin film lubrication (TFL) or extensive boundary lubrication as a new area of lubrication regime has been well studied by Spikes et al. [1, 2], Luo and Wen et al. [3–10], Hartl et al. [11, 12], Robbin [13], Hu et al. [14, 15] from 1990s. Some significant progress has been made in this area. TFL is also known as the lubrication of confined liquids which also have been well investigated by using the surface force apparatus (SFA) developed by Israelachvili and Tabor [16], Alsten [17], Granick [18], Klein [19] and so on. The effective viscosity in a nano-gap was found

J. Luo (*) State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China e-mail: [email protected] M. Ceccarelli (ed.), Technology Developments: the Role of Mechanism and Machine Science and IFToMM, Mechanisms and Machine Science 1, DOI 10.1007/978-94-007-1300-0_17, © Springer Science+Business Media B.V. 2011

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CB/hexadecane

30

Effective viscosity h

CAL/hexadecane CA/hexadecane CP/hexadecane

20

hexadecane 10

0 5

10

15

20

25

30

Film thickness (nm) Fig. 1  Isoviscosity with film thickness with different polar molecules [7]. Concentration: 2 wt.%; Load: 0.174 GPa

to be much larger than the bulk one. As shown in Fig. 1, Shen and Luo [7] found that isoviscosities of hexadecane with or without LC remained a constant that approximately equaled the bulk viscosity when film is thicker than 25 nm. As the film thickness decreased, the isoviscosity increased with different grades for different additives. The polarity strength of these liquid crystal molecules were listed as CB > CAL > CA > CP. Therefore, the addition of polar molecules into base oil is benefit that raises its isoviscosity. Xie et al. [9] found that the fluidity of a nonpolar liquid became much weaker after it was exposed to an electric field that is confined within a nanogap between a smooth plate and a highly polished steel ball. Their experimental results indicated that a ‘freezing’ of nanoconfined fluid, or a transformation from liquid into a solidlike form takes place (Fig. 2). The tail eventually disappeared from the interference pattern when the voltage was increased from 0 V to 98 V. When the external EF was removed, the bright tail reoccurred. The Scanning Tunnel Microscope (STM), Atomic Force Microscope (AFM), and computer simulation technology as powerful tools have brought a big storm to tribology in the past 20 years, and many new phenomena of friction at the nanoscale have been found. Bhushan et al. [20] have performed many tests and found some new relations between the micro-friction force and its related factors at the nano-scale. In order to probe the origin of friction, Qian et al. [21, 22] using AFM found that the friction was related to the shape and Young’s modulus of the AFM tip, the surface topography, and humidity. By using molecular dynamic simulation (MDS), Wang et al. [7, 23] investigated the origin of friction by using a simplified

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Fig. 2  Interference patterns of the n-hexadecane film at a velocity of 76.6  mm/s with a film thickness of 12 nm under a load of 27 N. External voltage was (a) 0 V, (b) 10 V, (c) 20 V, (d) 30 V, (e) 40 V, (f) 50 V, (g) 60 V, (h) 70 V, (i) 80 V, (j) 90 V, (k) 98 V, and (l) 10 s after the removal of the electric field [9]

system containing only one atom (Fig. 3) where the atom moves in a stick–slip way (Fig. 3b). The system becomes more stable if the stiffness increases or the potential waviness decreases, which means less energy loss and lower friction [23].

Green-Tribology Green-tribology includes the environment-friendly lubricants, anti-environmental pollution from wear contamination, reduction of tribo-noise, etc. As known, petroleum plays a vital role in industrial development and our lives. However, the world energy demand is increasing rapidly due to excessive use of petroleum products, and researchers are looking for alternative materials because of limited reservoirs of petroleum. Another serious problem associated with the use of petroleum products is the increase in pollutants emissions. Every year about five to ten million tons of petroleum products enter into the environment from spills, industrial, and municipal waste [24, 25]. So the need to find alternative materials is inescapable. Lubricants are one of these serious problems in industry because most lubricants consist of mineral oil with different additives that are harmful to the environment. Mineral oils usually have a high degradable temperature, and can be maintained a long time without experiencing hydrolysis (e.g. harmful to water for about 100 years if it flowed into water) [26]. Therefore, the green-lubricants represent a great hope for industry in the future.

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a k

x x0

b

Forward B

4

D

Force F

2

A

0

C

F

-2

E

G

-4

Backward 0

4

8

Distance X0

12

16

Fig. 3  Position and force of the moving atom as a function of traveling distance (a) system; (b) acting force [7, 23]

Vegetable Oil The increasing application of biobased lubricants could significantly reduce environmental pollution and contribute to the replacement of petroleum base oils. Vegetable oils are recognized as rapidly biodegradable and are thus promising candidates for use as base fluids in formulation of environment friendly lubricants [27]. Vegetable oil based products are environment friendly and non-toxic, and thus offer easier disposal as compared to petroleum products. There are also biodegradable synthetic oils offering improved stability and performance characteristics over refined petroleum oils, but prices for these niche products are higher than vegetable oils and significantly higher than petroleum-based lubricants [27]. Although many vegetable oils have excellent lubricity, they often have poor oxidation and low temperature stability. Vegetable oils include moringa oil, sunflower oil, cottonseed oil, rapeseed oil, canola oil, jatropha oil, peanut oil, and so on. Roegiers et al. [28] reported that the use of ionized vegetable oils significantly improves lubricity and anti-wear efficiency.

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Ionized vegetable oil film can support higher loads or heavier pressure, which can be used in running engines at dead points, bearings during cold start-up, thrust bearings of vertical turbines during start-up, railway truck axle box-guides, reduction gears, deep drawing, and so on [28]. Aloe mucilage is another kind of plant liquid which has the possibility to be a lubricant. Xu, Luo et al. [29] reported that the friction coefficient of aloe mucilage between different solid surfaces significantly decreased with the increase of velocity, but little variation with an increased normal load. The friction coefficient of aloe mucilage between WC and DLC surfaces is about 0.04 [29].

Nano-Particles as Additives The collapse of the lubrication film will induce adhesion and damage of tribosurfaces in relative motions. Usually, extreme pressure and anti-wear additives are used to improve the tribological performance of fluid lubricant for the reduction of friction and surface damage caused by severe conditions, e.g. high temperature, high pressure, high shear rate [30, 31]. In general, sulphur, chlorine, and phosphorous containing compounds are designed to cover metal surfaces chemically by forming easily sheared layers of sulphides, chlorines or phosphides, and thereby preventing severe wear and seizure. However, the usage of sulphur, chlorine, and phosphorus containing compounds has been restricted due to the environmental pollution. Therefore, new additives with less pollution potential for lubricants used in severe conditions have become targets for many tribologists [31]. Traditional solid lubricants, such as MoS2, graphite, C60, CeF3, and CeO2, have been added to lubricating oils or grease to improve their tribological properties. Many experimental results indicated that the addition of solid particles in oil was beneficial in reducing the wear rate and friction between two rubbing surfaces [30–32]. However, others showed that solid particles gave rise to an increase in wear rate and lubricant starvation [33, 34]. The reason for these phenomena is that the size and the concentration of particles have an important effect on tribological properties [35]. Nanoparticles have received considerable attention because of their excellent physical and chemical properties. However, the problem of agglomeration and adhesion of nano-particles needs to be solved, and therefore, the application of many nanoparticles is limited. In the past 20  years, nanoparticles, e.g. diamond, graphite, C60, Cu, TiO2, ZnS, CeF3, WS2, LaF3, and PbS, have been used as oil additives, and they show improved tribological properties of the base oil. Greenberg et al. [36] found about a 50% reduction in friction coefficient in the mixed lubrication regime by using WS2 nano-particles as an oil additive. SiO2 nanoparticles using hydrocarbons as surface modification agents can be dispersed stably in lubrication oils and can be used as an anti-adhesive additive [37]. Guo et al. [38] utilized tetrafluorobenzoic acid-modified TiO2 nanoparticles as a lubricant additive that also has good tribological behaviors.

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Diamond nanoparticles have attracted much attention of researchers because of its more outstanding properties in wear resistance, friction reduction, oxidation inhibition, low pollution and higher thermal conductivity than other nanoparticle additives. Diamond nano-particles have been used as an anti-scuffing additive by Shen et al. [30] and Chu et al. [39]. They found that the 3 vol% concentration of nano-particles in oil is the most favorable for reducing the mean friction coefficient and mean wear loss. Shen et al. [30] found that the hard spherical nano-particles plowed the two surfaces and produced many smooth micro-grooves in the rubbing process, and the friction force decreased with the sliding distance.

Rare Earth Materials as Additives The classification “rare earth elements” consists of 17 elements; they are, La, Ce, Pr, Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. The term “rare earth” was adopted in the 18th century due to fact that the minerals containing such elements are very rare and look like earth. A rare earth element has high activity, a large diameter, and a strong adhesion force which will result in its enrichment when rubbed on a surfaces. Many oxides or fluorides of rare earth elements, e.g. LaF3, CeF3, La2O3, have a good lubricity at high temperature. The friction coefficient of LaF3, CeF3 is about 0.2 at a temperature higher than 500°C. Han et al. [40] added nanoparticles of CeF3 into Ni-W coating with a percent of 6 wt.% and got a friction coefficient of 0.18 at the temperature of 700°C. Rare earth materials are expected to increase in importance in the near future.

Summary In the near future, the following problems in green tribology will draw much attention and some new green lubricants will be successful in application: (1) How to reduce the environmental pollution from wear contamination? (2) How to reduce tribo-noise, particularly in high speed trains, fast cars, and ultrasonic air plane? (3) How to develop new kinds of lubricant instead of mineral oils, such as waterbased lubricants, plant oils, plant liquid?

Bio-Tribology and Bionics Bio-tribology, a term proposed in the 1970s, includes tribology in human body and bionic-tribology, which is related to mechanics, material science, physics, chemistry, biology, medicine, etc. Tribology in the human body is a result of relative motion of parts of the body, e.g. joints, heart, eyes, tooth, mouth, skin, hair, blood

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vessel, and so on. In bio-tribology, the physiological reactions, self-adaptive and self-rehabilitative, usually exist in the tribological process. The difference of shape, elastic modules, and surface characteristics between organic surfaces and traditional tribo-surfaces cause more difficulties for researchers. There are many problems to be solved, e.g. the friction and extrusion between red blood cells and the walls of blood vessels, the mechanism of friction and wear of skin, impacting between blood and the surface of the heart valve. Bionic-tribology is focused on learning from nature, that is, researchers see special patterns on surfaces from natural plants or animals, e.g. the self-cleaning surface of the lotus leaf, the long proboscis of a mosquito which is very narrow but can suck blood easily, and the legs of the water strider which have a hierarchical structure with large numbers of oriented tiny hairs and nano-grooves. Bio-tribology is useful in the production of artificial joints, artificial hearts, artificial teeth, eyedrops, and skin oil. As regards artificial joints, about 100 million people a year need to replace one or more of their joints including hip joint, knee joint, ankle joint, elbow joint, shoulder joint, and wrist. Ultra-high molecular weight polyethylene (UHMWPE) was introduced as an artificial joint material in 1963 and continues to play an important role in convalescence engineering. Some new joint materials, e.g. titanium based alloy, Al2O3, CoCrMo alloys, have been investigated in order to extend the life of artificial joints to more than 50years. The wear particles including metal particles, UHMWPE particles, polymethyl methacrylate (PMMA) particles, ceramic particles, etc. will cause pathological changes near the joint surfaces. Mouth tribology has become of interest in recent years because more people pay more attention to their teeth and mandible joints. Zheng et  al. [41] measured the friction coefficients of different materials with a human tooth, which for Ti alloy with a lubricant of saliva is 0.15, and for stainless steel is 0.2. The eye is another typical bio-tribological system, in which the corneal thickness is about 520 mm with a roughness of 0.5 mm. In general, the load of eyelids on eyeballs is 200–250 mN, the tears usually keep a film with a thickness of 15 mm and a viscosity of 0.0013 Pas, and the friction coefficient is 0.005 during blinking with a shear rate about 15,000 1/s [42, 43]. The valve is the most important part of an artificial heart. Its reliability is directly related to the life of the person who has had an artificial heart implanted. The heart valve will sustain about 40 million impacts per year. In China, there are about 100 thousand people whose heart valves have been replaced by artificial ones a year, and only 40% of them can live for as long as 12 years [43]. Therefore, how to reduce impact wear and fatigue failure, or how to extend the life time of the artificial heart valve will continue to be a serious problem in the following years. Researcher inn bionic-tribology are working on the tribological properties and characteristics of surfaces similar to natural surfaces. In wetting bionic surfaces, more works have been focused on hydrophobic and hydrophilic surface, e.g. lotus leaf, nepenthes, feet of water strider, dung beetle, and pothead. In adhesion to bionic surfaces, many kinds of insects and animals have a stronger adhesion force between their feet and contacting surfaces because of their large number of hierarchical structures, such as the feet of mosquitoes, geckos, ants, spiders, bees, flies,

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Fig. 4  Hierarchical structure of Gecko toe [45]

grasshoppers, beetles, etc. The static friction force between an ant and a glass disc is more than 100 times the weight of the ant [44]. The gecko is another kind of interesting animal; due to its special feet, it can run rapidly on walls and ceilings, requiring high friction forces (on walls) and adhesion forces (on ceilings), with typical step intervals of 20 ms. Tian et al. [45] have investigated the adhesion force between a gecko toe which has a hierarchical structure and a solid surface (Fig. 4). They think that the rapid switching between gecko foot attachment and detachment is disclosed theoretically based on a tape model that incorporates the adhesion and friction forces originating from the van der Waals forces between the submicron-sized spatulae and the substrate. High net friction and adhesion forces are obtained by rolling down and gripping the toes inward to realize small pulling angles between the large number of spatulae in contact with the substrate. To detach, the high adhesion friction is rapidly reduced to a very low value by rolling the toes upward and backward, which peels the spatulae off perpendicularly from the substrates. From these mechanisms, both the adhesion and friction forces of geckos can be changed over three orders of magnitude, allowing for swift attachment and detachment during gecko motion [45].

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Super Lubricity Appearance of the superlubricity concept [46, 47] has gained attention from researchers in the field of tribology, machinery, physics, and chemistry. In ­practice, it is thought that when friction is at the scale of 0.001 or lower, the lubrication condition is thought to be in a superlubricity state. Research on superlubricity and its mechanism will strongly affect an explanation of the mechanism of lubrication and origins of friction. More importantly, it benefits industrial techniques and the development of the nano-techniques that have to face stronger frictions or surface forces. Superlubricity not only reduces the conservation of friction energy, but also provides a near-wearless condition. Thus, superlubricity will help human beings in the future to become free of the yoke of friction and wear. At the beginning of the 1990s, by theoretical calculation, Hirano and Shinjo [46, 47] found that when two arranged crystal surfaces move in certain commensurate surfaces and directions, friction vanishes, or a superlubricity state takes place due to the weak mutual interaction and relaxation between molecules. However, their experimental results of superlubricity have not been accepted due to their measured precision limits. There are two kinds of materials that have superlubricity-like properties. One is solid lubricant, such as high oriented pyrolytic graphite and MoS2 which show an ultralow friction in the special direction under a high vacuum condition [48], near-frictionless DLC film [49]. Another kind is water-based materials, e.g. polymer with water [50], ceramic material with water [51]. Klein et al. [50] made a superlubricity experiment with end-grafted chain film on the surface force microscope (SFA) where an ideal atomic smooth surface of mica is always used as couple surfaces to investigate the water-based lubricants, confining them with a given gap under a small normal pressure. The ‘molecular brush’ layer is formed on the mica surface and an ultralow coefficient of about 0.001 or lower can be attained at room temperature [52, 53]. There are also other kinds of lubricants reported to have superlubricity properties [54]. Some natural lubricants have much better performance than most artificial lubricants. The fluid in the joint of an animal can protect an organa from abrasion, which induces a friction coefficient lower than 0.003 [55]. It has been indicated that hyaluronic acid is contributive to reduce the friction coefficient, and the lubricating ability of such polysaccharides was reported to come from the super hydrophilicity [56, 57]. Arad et al. [58] obtained ultra low friction coefficients lower than 0.003 by the use of polysaccharides extracted from red algae, attributing it to the spiral chain structure. Recently, Ma et al. [59] found a new water-based lubricant with a friction coefficient about 0.002 under much higher pressure than that in SFA, which created a new system of superlubricity lubricant. Superlubricity research work is just at the preliminary stage. Systematic and theoretical analyses of the mechanism of superlubricity are needed [60]. The following problems need to be solved:

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1 . What is the relationship between ordered degree of molecules and superlubricity? 2. What is the mechanism of superlubricity? 3. What are the basic conditions for the transition from the non-superlubricity state to the superlubricity state? 4. Is there any other kind of lubricant with superlubricity?

Tribology in Nanomanufacturing Nanomanufacturing was defined in the web of Natural Science Found of America as encompassing all processes aimed toward building of nanoscale (in 1D, 2D, or 3D) structures, features, devices, and systems suitable for integration across higher dimensional scales (micro-, meso- and macroscale) to provide functional products and useful services. Nanomanufacturing includes both bottom-up and top-down processes, in which many are related to tribology. Nanomanufacturing brings many new challenges to tribologists. For example, in order to raise the areal density of a hard disc driver to more than 1,000 Gb/in2, how to get an atomic smooth surface and how to keep the fly height less than 2 nm are key problems [7, 61, 62]. In nanoprinting, the compactedness of space is related to nano-rheology and adhesion in solid and liquid interfaces [63, 64]. Nanomanufacturing is also very important in the manufacturing of integrated circuits (IC) where one difficulty is the planarization for the different kinds of material layers with different hardness, e.g., Cu layer, Ta layer, and SiO2 layer. The chemical mechanical planarization (CMP) is the most effective planarization tool in IC manufacturing. However, how to get a smooth surface with waviness and roughness at an atomic level is still a big problem.

Interaction of a Nanoparticle with a Solid Surface Observation of the Movement of a Nanoparticle A system of a fluorescence microscope for the nanoparticle observation has been developed by Xue and Luo [65, 66] using nanoparticles with a shell of SiO2 and the fluorescein inside with diameters about 40 ± 5 nm. The movement of these fluorescence nanoparticles in water can be observed. Xu and Luo [65] proved the existence of Marangoni flow in an evaporating water droplet through trajectories of these nanoparticles in a water droplet. Collision of Nanoparticles with Solid Surface In order to find whether a nanoparticle in collision with the worked surface in the CMP process can contribute to material removal or not, Xu and Luo[67] have

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Fig. 5  Surfaces impacted by slurry with 0.5% nanoparticles about 60 nm in diameter at a speed of 50 m/s with the exposure time of 10 min: (a) TEM images of the cross section of the surface layer and (b) AFM images of the surface after impacting

designed an experiment by using slurry including SiO2 nanoparticles impacting a solid surface adsorbing fluorescent nanoparticles and checking the variation of the images of fluorescent nanoparticles between, before and after the impacting to deduce the material removal. Their experimental results indicate that the adsorbed nanoparticles on a solid surface can hardly be removed by the hydrodynamic effect of the impacting liquid and by the collisions of the impacting nanoparticles if the impacting speed, the impacting time, and the particle concentration of the liquid are less than 7.2 m/s, 1 min, and 15 wt.% respectively. Therefore, it can be deduced that the effect of the collision between the abrasives and the wafer surface on the material removal can be negligible under the experimental condition. Xu et al. [68] used a cylindrical liquid jet containing deionized water and SiO2 nanoparticles to impact on a surface of a single crystal silicon wafer at a speed of 50 m/s with an incidence angle of 45°. Some crystal defects, lattice distortion, the rotation of grains, an amorphous layer containing crystal grains, craters, scratches, and atom pileups have been found in the surface layer of the silicon wafer after impacting (Fig. 5a) [68]. Impacting pits at nano-scale and atom pileups also were found by AFM (Fig. 5b).

Molecular Dynamic Simulation Molecular dynamic simulation (MDS) is a useful tool for the investigation of material behaviors at the atomic or molecular scale. A theoretical analysis of a nanoparticle in collision with a Si or SiO2 surface has been done by Luo, Duan, and Chen [7, 61, 69–71] by MDS. Effects of the incident angle, energy, cluster size, on the trajectory of a nanoparticle, the deformation, temperature, and pressure distribution in the damaged region, and the material removal rate (MRR) of the surface layer had been investigated by them with a system as shown in Fig. 6. Their results indicate that a successive shape change of the damaged region is created on the surface

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Fig. 6  Schematic diagram of a nanoparticle impacting on a crystal silicon surface and the surface configurations after impacting at different angles

as the incident angle q changes from 0° to 75° (Fig. 6) [61, 69]. Their results also indicate that there is a best size region of particles with which the most unit area energy will transfer from the particle into the impacted surface, and a highest MRR can be obtained [61, 70, 71].

Influence of Particles on the CMP Process In the CMP process, particles take a chief role for obtaining an ultra-smooth surface. The agglomeration of nano-particles in the CMP process will result in scratches on a polished surface, and the adhesion of nanoparticles on the polished surface will make much trouble for the cleaning process [61]. The surface of a silica nanoparticle is modified by the graft copolymerization of siloxanes with functional groups such as –OH, -NH2, -COOH, and a surface of the hard disk substrate

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Fig.  7  The roughness of hard disk substrate surface before and after surface modification of particles [61]

polished by such particles is improved from roughness Rz 0.114 nm to 0.089 nm and the surface defects such as micro-scratches, pits, and particle contaminations decreased greatly (Fig. 7) [61].

Other Interesting Areas Tribology in extreme hard conditions and surface texture related theory and ­technique are also very important. The tribology in conditions of extreme hardness includes tribology under a heavy load, at a high/low temperature, at a very high/low speed, in a high vacuum space, under acid/alkali corrosive condition, etc. Many tribologists are focused on the development of new lubricants and materials to fit the increasing needs, e.g. multi-alkylated of cyclopentanes (MACs) for high vacuum space [72]. Research on surface texturing is a hot point in recent years, which is related to material science, tribological theories, surface machining techniques, and working conditions. The early work on surface texturing is retrospect to 1977 [73]. It has become a viable option of surface engineering resulting in significant improvement in load capacity, wear resistance, and friction coefficient of mechanical components in the last 15 years [74]. The shape, the size, the distribution and the area density of surface textures are considered to be the most important parameters influencing tribological performances of textured surfaces. Various techniques have been employed to produce surface textures, and the laser surface texturing (LST) is probably the most effective so far. Efforts have also been made to improve current production techniques and to search for new methods of producing textures [75]. In addition, the tribology in new energy areas, the tribology in deep seas, the reduction of tribological noise of high speed traveling tools, anti-environmental pollution from wear contamination and wasted lubricants etc. will also absorb more attention.

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Conclusion Tribology has been well developed in the last 20  years. Some new concepts and new areas, e.g. superlubricity, tribology in nanomanufacturing, bio-tribology, etc. have been brought out in recent years, and they will absorb more attention and develop faster in the following 10  years. These questions or problems are to be solved in the development of tribology in the near future: 1 . What is the role of tribology in new energy area? 2. What is the mechanism of superlubricity and how to improve properties of superlubricity material to fit industry needs? 3. How to salve the lubrication of micro/nano-system? 4. How to solve the tribological problems of artificial organs, e.g. artificial heart, artificial limb, for the human body? 5. What can tribologists learn further from nature? 6. How to reduce the wear of machines in the deep sea, a high vacuum (