ROBOTICS ROBOTICS K.K. Appu Kuttan Professor NITK Surathkal Srinivas Nagar Karnataka (India) I.K. International Publishing House Pvt. Ltd. NEW DELHI • MUMBAI • BENGALORE The author and publisher of this book have used their efforts in preparing the book titled “Robotics”. These efforts include development, research and compilation of basic theories and principles for the effectiveness of the book. The author and publisher make no warranty of any kind expressed in the documentation contained in the book. The author and publisher shall not be liable in any event for incidental or consequential damage in connection with or arising out of use of the book. This book is intended for fundamental understanding of the robotics subject to the students. Published by I.K. International Publishing House Pvt. Ltd. S-25, Green Park Extension Uphaar Cinema Market New Delhi-110 016 (India) E-mail: [email protected] Branch Offices: A-6, Royal Industrial Estate, Naigaum Cross Road Wadala, Mumbai-400 031 (India) E-mail: [email protected] G-4, “Embassy Centre”, 11 Crescent Road Kumara Park East, Bangalore-560 001 (India) E-mail: [email protected] ISBN 978-81-89866-38-9 © 2007 I.K. International Publishing House Pvt. Ltd. All rights reserved. No part of this book may be reproduced or used in any form, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission from the publisher. Published by Krishan Makhijani for I.K. International Publishing House Pvt. Ltd. S-25, Green Park Extension, Uphaar Cinema Market, New Delhi-110 016. Printed by Rekha Printers Pvt. Ltd., Okhla Industrial Area, Phase II, New Delhi- 110 020. Contents Preface ix 1. Fundamentals of Robotics 1 1.1 Historical Development of Robot 1 1.2 Definitions of Industrial Robot 2 1.3 Classification 4 1.4 Degree of Freedom and Degree of Motion 13 1.5 Manipulation of Robot Components 14 1.6 Joints and Symbols 15 1.7 Work Volume and Work Envelope 16 1.8 Resolution, Accuracy and Repeatability 18 1.9 Robot Configuration 20 1.10 Economic and Social Issues 27 1.11 Numerical Examples 28 Exercise 31 2 Robot Programming and Modular Components 32 2.1 Robot Programming Methods 32 2.2 Advantages and Disadvantages of Robot 35 2.3 Requirements for a Robot in an Industry 36 2.4 Specifications of Robot 36 2.5 Operational Capabilities Level of a Robot 37 2.6 Modular Robot Components 38 2.7 Wrist Mechanism 46 2.8 Numerical Examples 46 Exercise 51 3. Robot Sensors 52 3.1 Internal Sensors 53 3.2 External Sensors 59 3.3 Force Sensors 72 3.4 Thermocouples 77 vi Contents 3.5 Performance Characteristics of a Robot 79 3.6 Static Performance Characteristics 79 3.7 Dynamic Performance Characteristics 81 3.8 Standard Test Signals 82 3.9 Controllers 85 3.10 Time Response of a Second Order System 88 3.11 Characteristics of a Under Damped System 92 3.12 Steady State Response 95 3.13 Steady State Dynamic Characteristic 96 3.14 Examples for Illustration 98 Exercise 104 4. Robot Actuators 106 4.1 Hydraulic and Pneumatic Actuators 107 4.2 Electrical Actuators 115 4.3 Brushless Permanent Magnet DC Motor 124 4.4 AC Servomotor 125 4.5 Stepper Motor 125 4.6 Micro Actuators 127 4.7 Micro Gripper 129 4.8 Micro Motor 130 4.9 Drive Selection 131 4.10 Examples for Illustration 133 Exercise 138 5. Motion Conversion and Drives 140 5.1 Rotary to Rotary Motion Conversion 140 5.2 Harmonic Drives 144 5.3 Rotary to Linear Motion Conversion 147 5.4 Parts Presentation Methods 155 5.5 Robot Safety 157 5.6 Safe Guarding 162 5.7 Numerical Examples 163 Exercise 167 6. Mathematical Modeling of a Robot 169 6.1 Basics of Matrix Representation 169 6.2 Link Equations and Relationships 174 6.3. Problem with DH Presentation 193 6.4 Differential Motion and Velocities 194 6.5 Calculation of the Jacobian for a Robot 197 6.6 Jacobian for Revolute Joint 199 6.7 Trajectory Control 200 Contents vii 6.8 Numerical Examples 202 Exercise 208 7. Dynamics of a Robot 211 7.1 Stiffness Control of a Robot End Effector 212 7.2 Dynamic Equations for Robots 227 7.3 Examples for Illustration 240 Exercise 255 8. Advanced Robot Systems 257 8.1 Heuristics Decision for Robot 258 8.2 Fuzzy Logic for Robot Control 259 8.3 Artificial Neural Network in Robotics 265 8.4 Biped Robot 274 8.5 Biomimetic Robotics 283 8.6 Robot Calibration 286 Appendix A: Laplace Transform 290 Appendix B: Pneumatic and Hydraulic Systems 293 Symbols and representation of standards 293 Appendix C: Routh Herwitz Criterion 305 References 307 Textbooks 307 Journal Papers 309 Index 313 Preface This book was originally my lecturer notes written for Mechanical Engineering department Robotics course. With the encouragement from different professors and students, it was modified to the present form. This book is intended for senior or introductory graduates course in Robotics, as well as practising engineers who would like to learn about robotics. Although the book covers a fair amount of kinematics and dynamics of the robot, it also covers the sensors and actuators used in robotics system and development and classifications. Thus it can be used by mechanical engineers, electrical and electronic engineers, computer engineers and engineering technologists. The slow growth of the robotic industry in India is due to interdisciplinary nature of robotics itself. The field of robotics combines aspects of electrical, mechanical, computer science, mathematics and economics. There is at present a critical shortage of trained people with the cross disciplinary knowledge necessary to integrate successfully the various technologies involved in robotics application. It is the task of universities to provide such a cross-disciplinary education. The book has written primarily for the university students who may have little or no exposure to the subject of robotic. It also can be used by the students in the different engineering disciplines. Recently numbers of textbooks have appeared that provide comprehensive treatment of robotics. However, the present one provides a self-contained introduction to robotics. Author 1 Fundamentals of Robotics Robotics is an applied engineering science that has been referred to as a combination of machine tool technology and computer science. It includes diverse fields as machine design, control theory, micro-electronics, computer programming, artificial intelligence, human factors and production theory. Research and development are proceeding in all of these areas to improve the way robots work or think. Advancement in technology will enlarge the scope of the industrial applications of robots. Robots are very powerful elements of today’s industry. They are capable of performing many different tasks and operations with precision and do not require common safety and comfort elements humans need. The subject of robotics covers many different areas. Robots alone are handy and useful. They are used together with other devices, peripherals and other manufacturing machines. They are generally integrated into a system, which as a whole is designed to perform a task or do an operation. 1.1 HISTORICAL DEVELOPMENT OF ROBOT In earlier days men were thought of machines that mimic humans and their actions, which came as fiction novel. Mary Shelly in England published a novel in 1817 titled ‘Frankenstein’ which deals with the story of a scientist who wants to create a monster human, which then proceeds to raise a havoc in the local community. Karel Capek, a Czechoslovak playwright in 1922 wrote a story called “Rossunis Universal Robot” and introduced the word Robota meaning a slave worker. When Robota was translated into English, the word became Robot. The story concerns a brilliant scientist named Rossum and his son who develop a chemical substance similar to protoplasm. They use the substance to manufacture robots. Their plan is that the robots will serve humankind obediently and do all the physical labor. Among science fiction, Isaac Asimova has contributed a number of stories about robots. He is credited with coining the term ‘Robotics’. The machine, robotics 2 Robotics performs on the basis of three principles, which are known as the three laws of robotics according to Asimova. They are: (a) A robot should not injure a human being or life. (b) A robot should obey the orders of the master without conflicting the first law. (c) A robot should protect its own existence without conflicting first and second laws. These laws are very important for the existence of robots and even in the industry where robots are working from the safety point of view. Human interference in the robot-working environment may cause disaster for the life. In 1954 George Devol developed the first programmable robot. In 1961, US patent 2988237 was issued to George Devol for his programmed article transfer robots for Unimate Company. The first industrial robot appeared in 1962 in General Motors, USA supplied by Unimation. In 1967, Unimate introduced mark II robot to Japan for spray painting application. In 1968, an intelligent robot called Shakey was built at Stanford Research Institute (SRI) which has three rotation motions called articulated arm. In 1972, IBM developed a rectangular coordinate robot called IBM7565 is a Cartesian robot. In 1978, Unimation developed a polar robot called PUMA. Most companies that made robots in the mid 1980 no longer exist except those that made industrial robots. The companies are adapt Robotics, Stanford Robots, Funuc Robots and North America, Inc. Robots. Since 1983 onwards robotics became a very popular subject, both in industry as well as academia. Many nations started learning courses on robotics from 1983 onwards.