FUZZY SYSTEMS Modeling and Control THE KLUWER HANDBOOK SERIES ON FUZZY SETS Series Editors: Didier Dubois and Henri Prade FUZZY SETS IN DECISION ANALYSIS, OPERATIONS RESEARCH AND STATISTICS, edited by Roman Slowmski ISBN: 0-7923-8112-2 FUZZY SYSTEMS Modeling and Control edited by Hung T. Nguyen New Mexico State University and Michio Sugeno Tokyo Institute of Techno/ogy 111... " SPRINGER-SCIENCE+BUSINESS MEDIA, LLC ISBN 978-1-4613-7515-9 ISBN 978-1-4615-5505-6 (eBook) DOI 10.1007/978-1-4615-5505-6 Library of Congress Cataloging-in-Publication Data A C.I.P. Catalogue record for this book is available from the Library of Congress. Copyright © 1998 by Springer Science+Business Media New York Originally published by Kluwer Academic Publishers in 1998 Softcover reprint of the hardcover 1s t edition 1998 All rights reserved. No part ofthis publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, mechanical, photocopying, recording, or otherwise, without the prior written permission ofthe publisher, Springer Science+Business Media, LLC. Printed on acid-free paper. Contents Series Foreword xiii Contributing Authors xv Introduction: The Real Contribution of Fuzzy Systems 1 Didier Dubois, Hung T. Nguyen, Henri Prade, and Michio Sugeno References 14 1 Methodology of Fuzzy Control 19 Hung T. Nguyen and Vladik Kreinovich 1.1 Introduction: Why Fuzzy Control 19 1.1.1 Traditional control methodology and its limitations 20 1.1.2 What we can use instead of the classical control model 23 1.2 How to Translate Fuzzy Rules into the Actual Control: General Idea 25 1.3 Membership Functions and Where They Come From 28 1.4 Fuzzy Logical Operations 38 1.5 Modeling Fuzzy Rule Bases 43 1.6 Inference From Several Fuzzy Rules 46 1.7 Defuzzification 49 1.8 The Basic Steps of Fuzzy Control: Summary 51 1.9 Tuning 51 1.10 Methodologies of Fuzzy Control: Which Is The Best? 53 References 59 2 Introduction to Fuzzy Modeling 63 Kazuo Tanaka and Michio Sugeno 2.1 Introduction 63 vi FUZZY SYSTEMS: MODELING AND CONTROL 2.2 Takagi-Sugeno Fuzzy Model 64 2.3 Sugeno-Kang Method 65 2.3.1 Structure identification 65 2.3.2 Prediction of water flow rate in the river Dniepr 69 2.4 SOFIA 69 2.4.1 Algorithm 70 2.4.2 Prediction of CO concentration at a traffic intersection 79 2.4.3 Prediction of O2 concentration in a municipal refuse incinerator 81 2.5 Conclusion 84 References 87 3 Fuzzy Rule-Based Models and Approximate Reasoning 91 Ronald R. Yage1' and Dimita1' P. Filev 3.1 Introduction 91 3.2 Linguistic Models 92 3.3 Inference with Fuzzy Models 93 3.4 Mamdani (Constructive) and Logical (Destructive) Models 95 3.5 Linguistic Models With Crisp Outputs 103 3.6 Multiple Variable Linguistic Models 105 3.7 Takagi-Sugeno-Kang (TSK) Models 112 3.8 A General View of Fuzzy Systems Modeling 113 3.9 MICA Operators 114 3.10 Aggregation in Fuzzy Systems Modeling 115 3.11 Dynamic Fuzzy Systems Models 120 3.12 TSK Models of Dynamic Systems 129 3.13 Conclusion 131 References 131 4 Fuzzy Rule Based Modeling as a Universal Approximation Tool 135 Vladik K1'einovich, Geo1'ge C. MOUZOU1'is and Hung T. Nguyen 4.1 Introduction 135 4.1.1 Why universal approximation 135 4.2 Main Universal Approximation Results 137 4.2.1 Universal approximation property for the original Mamdani approach 137 4.2.2 Generalizations of the standard fuzzy rule based modeling methodol- ogy have a universal approximation property 140 4.2.3 Simplified versions of the standard fuzzy rule based modeling method- ology also have a universal approximation property 144 4.2.4 Fuzzy rule-based systems are universal approximation tools for dis- tributed systems 145 4.2.5 Fuzzy rule-based systems are universal approximation tools for dis- crete systems: Application to expert system design 147 Contents vii 4.3 Can We Guarantee That The Approximation Function Has The Desired Prop erties (such as smoothness, simplicity, stability ofthe resulting control, etc.)? 149 4.3.1 Is fuzzy control a universal approximation tool for stable controls? 152 4.3.2 Is fuzzy rule based modeling methodology a universal approximation tool for smooth systems? 153 4.3.3 Is fuzzy rule based modeling a universal approximation tool for com- putationally simple systems? 155 4.4 Auxiliary Approximation Results 156 4.4.1 An overview 156 4.4.2 Usin~ additional expert information (fuzzy models and fuzzy control ru~~ ~7 4.4.3 Expert rules that use unusual logical connectives 158 4.4.4 Taking the learning process into consideration (fuzzy neural networks) 158 4.5 How To Make The Approximation Results More Realistic 161 4.5.1 A general overview 161 4.5.2 Inaccuracies in the input data 161 4.5.3 Can we have fewer rules? 164 4.6 From All Fuzzy Rule Based Modeling Methodologies That Are Universal Appriximation Tools, Which Methodology Should We Choose? 166 4.6.1 Main results. Part I. Best approximation 167 4.6.2 Main results. Part II. Best model 168 4.7 A Natural Next Question: When Should We Choose Fuzzy Rule Based Mod- eling In The First Place? And When Is, Say, Neural Modeling Better? 169 4.7.1 Smoothness and stability 169 4.7.2 Computational complexity 170 4.7.3 Conclusions 175 4.7.4 Collaborate, not compete 176 References 177 5 Fuzzy and Linear Controllers 197 Laurent Foulloy and Sylvie Galichet 5.1 Introduction 197 5.2 Modal Equivalence Principle 199 5.2.1 Using the Modal Equivalence Principle 202 5.3 Application to PI Controllers 203 5.3.1 Rule Base 203 5.3.2 Membership functions 204 5.3.3 Outputs for Modal Values 204 5.3.4 Using the Modal Equivalence Principle 205 = = 5.3.5 Example with a f3 1 206 5.3.6 Exact Equivalence 209 5.4 Application to State Feedback Fuzzy Controllers 209 5.4.1 State Feedback Control 209 = = 5.4.2 Single-Input, Single-Output Process (m p 1) 211 5.4.3 Multidimensional Mamdani's Controllers 214 5.4.4 Multi Single-Output Mamdani's Controllers 214 viii FUZZY SYSTEMS: MODELING AND CONTROL 5.4.5 Applications 215 5.5 Equivalence for Sugeno's Controllers 217 5.5.1 Modal Equivalence Principle 217 5.5.2 Control Law between the Modal values 218 5.5.3 Multidimensional Sugeno's Controllers 220 5.6 Conclusion 222 References 223 6 Designs of Fuzzy Controllers 227 Rainer Palm 6.1 Introduction 227 6.2 Fuzzy Control Techniques 229 6.2.1 The Design Goal 230 6.2.2 Fuzzy Regions 233 6.2.3 FC techniques for systems and controllers 234 6.3 The FC as a Nonlinear Transfer Element 237 6.3.1 The Computational Structure of a FC 237 6.3.2 The Transfer Characteristics 246 6.3.3 The Nonlinearity of the FC 248 6.4 Heuristic Control and Model Based Control 251 6.4.1 The Mamdani Controller 252 6.4.2 Sliding Mode FC 253 6.4.3 Cell Mapping 258 6.4.4 TS Model Based Control 261 6.4.5 Model based Control with Lyapunov linearization 263 6.5 Supervisory Control 266 6.6 Adaptive Control 267 References 270 7 Stability of Fuzzy Controllers 273 K azuo Tanaka 7.1 Introduction 273 7.2 Stability Conditions Based on Lyapunov Approach 274 7.2.1 Takagi and Sugeno's fuzzy model 274 7.2.2 Stability conditions 276 7.3 Fuzzy Controller Design 278 7.3.1 Parallel distributed compensation 278 7.3.2 Stability conditions 280 7.3.3 Common B matrix case 286 References 288 8 Learning and Tuning of Fuzzy Rules 291 Contents ix Hamid R. Berenji 8.1 Introduction 291 8.2 Learning Fuzzy Rules 292 8.2.1 Fuzzy C-Means Clustering 292 8.2.2 Decision tree systems 293 8.2.3 Using Genetic Algorithms to generate Fuzzy Rules 293 8.2.4 Berenji-Khedkar's linear fuzzy rules generation method 293 8.3 Tuning Fuzzy Rules 295 8.3.1 ANFIS 295 8.3.2 GARIC 296 8.3.3 Fuzzy Q-Learning and GARIC-Q 301 8.4 Learning and Tuning Fuzzy Rules 305 8.4.1 CART-ANFIS 305 8.4.2 RNN-FLCS 305 8.4.3 GARIC-RB 306 8.5 Summary and Conclusion 307 References 307 9 Neurofuzzy Systems 311 Witold Pedrycz, Abraham Kandel, and Yan-Qing Zhang 9.1 Introduction 311 9.2 Synergy of Neural Networks and Fuzzy Logic 315 9.3 Fuzzy sets in the technology of neurocomputing 317 9.3.1 Fuzzy sets in the preprocessing and enchancements of training data 317 9.3.2 Metalearning and fuzzy sets 320 9.3.3 Fuzzy clustering in revealing relationships within data 322 9.3.4 A linguistic interpretation of computing with neural networks 323 9.4 Hybrid fuzzy neural computing structures 326 9.5 Fuzzy neurocomputing - a fusion of fuzzy and neural technology 328 9.5.1 Basic types of logic neurons 329 9.5.2 OR / AND neurons 332 9.5.3 Referential logic-based neurons 332 9.5.4 Approximation of logical relationships - development of the logical processor 337 9.5.5 Learning 340 9.6 Constructing Hybrid Neurofuzzy Systems 343 9.6.1 Architectures 343 9.6.2 Learning algorithms of neural fuzzy networks 345 9.6.3 Learning algorithms ofcompensatory neural fuzzy networks 351 9.6.4 Designing neurofuzzy systems 353 9.7 Summary 360 References 362 10 Neural Networks and Fuzzy Logic 381 Nadipuram (Ram) R. Prasad x FUZZY SYSTEMS: MODELING AND CONTROL 10.1 Introduction 381 10.2 Liquid Level Control Problem 383 10.3 Fuzzy Rule Development 385 10.3.1 Case 1: No Restrictions on Flow Rates 388 10.3.2 Case 2: Input/Output Flow Rate Control 388 10.3.3 Pseudo-Rules 388 10.4 Integrated System Architectures 390 10.4.1 FNN2 Architecture 391 10.5 FNN3 Training Algorithm 392 10.5.1 FNN2 Simulation Results 396 10.5.2 FNN3 Architecture 396 10.6 Conclusions 400 References 400 11 Fuzzy Genetic Algorithms 403 Andreas Geyer-Schulz 11.1 Introduction 403 11.2 What is a genetic algorithm? 411 11.3 Fuzzy genetic algorithms 423 11.3.1 Table-driven agents: Coding the syntax 423 11.3.2 Table-driven agents: Coding the semantic 427 11.3.3 Table-driven agents: Combinations 431 11.3.4 Simple reflex agents: Variants of messy genetic algorithms 431 11.4 Fuzzy Genetic Programming 433 11.4.1 Context-Free Fuzzy Rule Languages 433 11.4.2 Simple Genetic Algorithms over k-Bounded Context-Free Languages 437 11.4.3 Non-Deterministic Environments 443 11.4.4 Results and Applications 449 References 450 12 Fuzzy Systems. Viability Theory and Toll Sets 461 J. P. Aubin and O. Dordan 12.1 Introduction 461 12.2 Convexification Procedures 462 12.3 Toll Sets 467 12.3.1 Toll Sets and Toll Maps 468 12.3.2 Operations on Toll Sets 469 12.3.3 The Cramer Transform 472 12.3.4 Analogy between Integration and Optimization 476 12.4 Fuzzy or Toll Differential Inclusions 477 12.4.1 Set-Valued Maps 477 12.4.2 The Viability Theorem 478 12.4.3 Toll Differential Inclusion 479 12.4.4 Example: Random Differential Equations 480 12.4.5 Viability Theorem for Toll Differential Inclusions 481