Simulation by Bondgraphs

Transcription

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2 Jean U. Thoma Simulation by Bondgraphs Introduction to a Graphical Method Springer-Verlag Berlin Heidelberg New York London Paris Tokyo Hong Kong 1990

3 Professor Dr. Jean Ulrich Thoma Dept. of Mechanical Engineering University of Waterloo Ontario, Canada N2L 3G 1 Thoma Consulting CH-6300 Zug, Switzerland ISBN-13: e-isbn-13: : / Library of Congress Cataloging in Publication Data Thoma, Jean U. (Jean Ulrich), Simulation by bondgraphs : introduction to a graphical method / Jean U. Thoma. Includes bibliographical references. ISBN-13: (U.S. : alk. paper) 1. Bond graphs. I. Title. II. Title: Simulation by bond graphs. TA338.B6T '.00l'l-<ic2Q This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in other ways, and storage in data banks. Duplication of this publication or parts thereof is only permitted under the provisions of the German Copyright Law of September 9, 1965, in its current version, and a copyright fee must always be paid. Violations fall under the prosecution act of the German Copyright Law. Springer-Verlag Berlin Heidelberg 1990 The use of registered names, trademarks, etc. in this publication does not imply, even in the absence' of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Typesetting: Thomson Press India Ltd., India; Printed on acid-free paper

4 Preface The idea of this new Bondgraph book appeared during the authors stay at Osaka University in spring 1987 as fellow of the JSPS (Japanese Society for the Promotion of Science). Instead of having my 1975 book translated into japanese I felt it needed to be completely rewritten. The japanese edition is under way as a joint-venture with Prof. N. Suda of Osaka University and should be available soon by Corona Publisher in Tokyo as Nr 9 of their series on Modern Control Engineering. The basic plan comes from myoid book on Bondgraphs (Thoma 1975), meanwhile published also in German and Italian. It has been modified from teaching and consulting experience, particularly from the graduate course "Modern Machine Design by Bondgraphs" at the University of Waterloo, Ontario, Canada. Many of the 20 worked examples come from the industrial simulation of real machines, installations and systems. Since the early years the PC (Personal Computer) has changed the working environment of the modern engineer and scientist, as with many other professions. Today (1990), the programing power of Bondgraphs produces impressive results on inexpensive personal machines. Bondgraphs stem from the ingenuity of Henry Paynter at MIT (Cambridge, USA) since the 1960ties. They are a representation of engineering systems on paper by letter elements and their interconnections, called bonds. They posses a myriad of advantages (Margolis 1985) which become impressive, even world shaking with moderately complex simulations. We therefore expect a great increase of bondgraphing in the future. Our intended readers remain the same: Any person, student or engineer in industry who needs to simulate systems with mechanical, hydraulic or electric parts. Due to its application oriented character, bond graphing is most useful for increasing the efficiency of new product design. Further, the book can be used for Bondgraph courses and will be by the author for his courses Modebond and Simbond (Appendix 1). We expect no prior knowledge of Bondgraphs from our readers, only a feeling for control engineering, including block diagrams, transfer functions and stability. Interest in interdisciplinary engineering and analogies will help. In the first chapter we describe graphical system models in general whilst Bondgraphs are introduced in Chapter 2. The following 3 chapters treat the

5 VI Preface writing of Bondgraphs for mechanical, hydraulic and electric systems with worked examples. Computational details and elimination of numeric difficulties come in chapter 6, in order to also teach the practical aspects of simulation. Chapter 7 speaks about thermodynamics by Bondgraphs with extension to thermal engines and chemical networks. More involved questions are treated in chapter 8 and the final chapter brings further worked examples. The examples are worked with the TUTSIM (1988) program, which is a fast and powerful program for microcomputers. However, other programs can be used and we encourage our collaborators and students to do so in order to gain experience with the strong and weak points of each program. Each TUTSIM listing is like a set of mathematical equation written in a condensed form; reconverting to usual mathematical writing is immediate (Fig. 2.24/2.25). It can then be converted to BASIC, PASCAL, C, etc., which include other unconventional writings of mathematical equations. In summary, the problems and pitfalls of numerical mathematics are universal. Today (1990), a book is a data carrier, an alternative to telephone wires and computer diskettes. We have carefully optimised the accessibility, the weak point of books compared to diskettes. So the start is easy, but difficulty increases both with the chapters and with the sections within a chapter. Fitting modern times, the efficiency of information acquisition by the reader is greatly improved by the personal play with the computer, including the worked examples. Hence we recommend the reader to use his PC as often as possible. It is fun and learning at the same time. In order to make study and play with the examples easier, the reader can order a diskette with the worked examples and a rudimentary form a TUTSIM for a nominal fee. Concluding, we the authors of Bondgraph books and papers, enjoy the power and beauty of Bondgraphs in teaching, research and consulting since many years. We wish to share our experience and emotions with our readers. March 1990 Jean U. Thoma A diskette with the listings of the worked examples and a rudimentary form of TUTSIM can be obtained from: in Europe: Meerman Automation, Postbus 154, NL 7160 AC Neede Tel , Fax in America: TUTSIM Products, 200 California A V #212, Palo Alto, CA 94306, USA Tel. (415) , Fax (415)

6 Table of Contents 1 Simulation and Graphical System Models Setting the Stage Networks for Engineering Mixed Introductory Topics Bondgraphs as Networks for Power and Signal Exchange Word Bondgraphs and Main Bondgraph Variables Bondgraph Standard Elements Computation Marks, Power and Causality Simulation from Blockdiagrams and Bondgraphs Nonlinearities and Block-Bondgraphs Multiport Bondgraph Elements Junction Structures and Transformations Simulation and Design of Mechanical Engineering Systems Opening ofthe Application Chapters Mechanical Systems with Ground Reference Systematic Writing of Mechanical Bondgraphs with Moving Reference Points Slip, Clutches and Electric Induction Motors Transmissions and Efficiencies Simulation of Fluid Power Systems and Hydrostatic Drives Hydrostatic Power in Fluid Flow Valve Controlled Actuators and Servomotors Circuits and Hydrostatic Transmissions Special Components and Devices... 71

7 VIII Contents 5 Electrical Circuits, Drives and Components Electric Circuits and Components Electric Motors Capacitors, Inductors, Actuators and Real Transformers Computational Overview, Practical Procednres and Problems Programs for Simulation from a Bondgraph... " Linear Control Theory, Eigenvalues and Calculating Step... " Stability Preview and Steady State Bondgraphs Eigenvalue Estimation and Dynacheck Causality Problems and Algebraic Loops Compact Parameters and Paracheck Causal Loops and Inspectional Analysis Applications to Thermodynamics, Chemistry and Biology Meet and Love Entropy Convection, Matter Flow and Solar Energy Networks in Chemistry and Physics Selected Questions Multibonds, Robotics and Circuit Theorems Bondgraphs for Elements Distributed in Space Shocks, Collisions and Hysteresis Analogies, Linear Graphs and Portality The Problem of Alternating Current Bondgraphs Further Worked Examples Hydraulic Examples Thermofluid Examples Appendices Al Organization of Bondgraph Courses A2 Note on Bondgraph Standards and Graphics A3 Table>of the Main Bondgraph Elements Glossary of Frequent Terms in English, French, and German References Snbject Index