Libro Control Moderno

Introduction to Physical System Modelling

Peter E. Wellstead

Electronically published by: www.control-systems-principles.co.uk

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Copyright and Usage Notice
This book was originally published in paper form by Academic Press Ltd in 1979, with the details given. In the year 2000, copyright was returned to the author, and this electronic version is released by Control SystemsPrinciples, via its website www.control-systems-principles.co.uk, and subject to the following conditions. Peter E Wellstead asserts his rights to be recognised as the sole author and copyright holder of this book and its contents. This book may be used subject to the following conditions: • The book should be used for personal or educational purposes only, and not for direct financial gain. • The book maydistributed to third parties provided it is done so free of charge, and as an entire work with the authorship clearly recognised. • The book may not be offered for resale under any circumstances without written permission from the copyright holder

Electronically published by: www.control-systems-principles.co.uk

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Publishing Information
Electronic Edition
Title: Introduction toPhysical System Modelling Author: P. E. Wellstead Copyright: 2000 Peter E Wellstead Electronic Publisher: Control Systems Principles, (www.control-systems-principles.co.uk) Setting: Laser Words, Chennai, India.

Original Paper Edition
Title: Introduction to Physical System Modelling Author: P. E. Wellstead Copyright: 1979 Academic Press Ltd Publisher: ACADEMIC PRESS LTD, 24/28 Oval Road London NW1British Library Cataloguing Data: Wellstead, P. E., Introduction to physical system modelling. ISBN: 0-12-744380-0 Setting and Printing: Litho Ltd, Whitstable, Kent, Great Britain.

Electronically published by: www.control-systems-principles.co.uk

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Preface to the 1979 Paper Edition
This book has arisen from efforts to formulate a simple unified approach to system modelling. In particular,the aim was to develop modelling in such a way that it would compliment dynamical systems analysis and control systems studies. Experience has shown that the modern heavily theoretical approach to control systems analysis and design has caused a decline in the intuitive understanding of engineering systems and the way in which they behave. One way of establishing this understanding is through anappreciation of system modelling methods. Of corresponding importance is a knowledge of the fundamental properties which are shared by all physical systems. The unifying theme used in this book is the interpretation of systems as energy manipulators. The idea being that the perceived dynamical behaviour of a physical system is the outward manifestation of the energy transactions within the system.In this way a wide range of systems can be handled in a common framework, with energy as the central concept. The notion of energy as a unifying agent is not new. It flows directly from the theories of Hamilton and Lagrange and occurs in the work of Firestone and his contemporaries. In recent years it has come into prominence by way of the bond graphic methods of H. M. Paynter. However, this is thefirst point at which all the established methods of system modelling have been drawn together in one text. In fact a key feature of the book is the way in which network modelling, variational modelling and bond graph methods are presented with energy handling as a common theme. The potential range of a book on modelling is enormous, and to make the task manageable I have been selective. To thisend the book is restricted to lumped parameter systems. In the same spirit, the highly specialized areas such as chemical process and reaction modelling have been excluded. The space gained in this way has been used to introduce a series of case studies. These are brief discussions of real modelling problems in which the dynamical equations are obtained in a number of ways each of which is linked...