DESIGN OF ANALOG FUZZY LOGIC CONTROLLERS IN CMOS TECHNOLOGIES

DESIGN OF ANALOG FUZZY LOGIC CONTROLLERS IN CMOS TECHNOLOGIES

Design of Analog Fuzzy Logic Controllers in CMOS Technologies Implementation, Test and Application by Carlos Dualibe Universidad Católica de Córdoba, Argentina Michel Verleysen Université Catholique de Louvain, Belgium and Paul G.A. Jespers Université Catholique de Louvain, Belgium KLUWER ACADEMIC PUBLISHERS NEW YORK, BOSTON, DORDRECHT, LONDON, MOSCOW

ebook ISBN: 0-306-48014-X Print ISBN: 1-4020-7359-3 2003 Kluwer Academic Publishers New York, Boston, Dordrecht, London, Moscow Print 2003 Kluwer Academic Publishers Dordrecht All rights reserved No part of this ebook may be reproduced or transmitted in any form or by any means, electronic, mechanical, recording, or otherwise, without written consent from the Publisher Created in the United States of America Visit Kluwer Online at: and Kluwer's ebookstore at: http://kluweronline.com http://ebooks.kluweronline.com

Contents Contributors Acknowledgements Preface INTRODUCTION FUZZY LOGIC AND FUZZY SYSTEMS ANALOG BASIC BUILDING BLOCKS iii v vii 1 13 39 MIXED-SIGNAL PROGRAMMABLE FUZZY LOGIC CONTROLLERS TIME-DOMAIN SIGNAL ANALYSIS USING FUZZY LOGIC GENERAL CONCLUSIONS Bibliography Index 107 155 195 199 209 i

Contributors Carlos Dualibe Laboratorio de Microelectrónica Universidad Católica de Córdoba Camino a Alta Gracia, Km 10 5016-Córdoba, Argentina Michel Verleysen and Paul G. A. Jespers DICE Laboratory Université catholique de Louvain Place du Levant, 3 1348-Louvain-la-Neuve, Belgium iii

Acknowledgements We would like to express our gratitude to all persons who contributed in the realization of this book. We are grateful to Prof. Denis Flandre, Prof. Piotr Sobieski and Prof. Vincent Wertz from the Université catholique de Louvain (UCL) and Prof. Joos Vandewalle from the Katholieke Universiteit Leuven (KUL), for their helpful remarks that have certainly improved this manuscript. We thank the Secrétariat à la coopération internationale of the UCL, the Belgian FNRS (Fond National pour la Recherche Scientifique) and the Universidad Católica de Córdoba (UCC) in Argentina, for their financial support. Michel Verleysen is a FNRS Senior Research Associate. We are plenty indebted with our colleagues from DICE laboratory at UCL, for the nice and friendly environment at the laboratory. We specially thank to Brigitte Dupont and her group for providing us the state-of-the-art on informatics. Our gratefulness is extended to all professors of the UCC for their encouragement. Our special thank is addressed to Prof. Carlos Marqués, Prof. Oscar Sartori, Prof. Eduardo Toselli, Prof. Carlos Diamanti and Prof. Miguel Moreno S.J., for their intense support for this research. Finally, we thank to Catherine, Denise, Dina and Emiliano, our families. Without their endless patience, this book would have never been accomplished. Carlos Dualibe, Michel Verleysen and Paul G. A. Jespers. Louvain-la-Neuve, Belgium, 2002. v

Preface In the last years, the astonishing growth of the Japanese industry in producing a substantial number of consumer appliances using Fuzzy Controllers put Fuzzy Logic on the focus of the scientific community. At the beginning, the most popular applications of Fuzzy Logic were found in the domain of Control System. Nowadays, the application of this soft-computing technique has been extended to other fields such as Signal Processing, Image Processing and Switching Power Control, for instance. As real-time applications need ever faster, more autonomous and less power-consuming circuits the choice of on-chip controllers becomes an interesting option. The attractiveness of analog circuits for implementing Fuzzy hardware relies on its natural compatibility with most used Fuzzy algorithms and the needlessness of A/D and D/A converters for interfacing sensors and actuators. This book deals with the implementation, test and application of programmable and reconfigurable Analog Fuzzy Logic Controllers in standard CMOS technologies in three fundamental stages. In the first part, the analysis and design of basic analog building blocks have been addressed. Main topics concerning their accuracy, programmability, interfacing and VLSI compatibility for CMOS implementation have been focused. Some novel circuits are presented while others are optimized towards an improved behavior. The second part comprises the implementation and test of programmable and reconfigurable mixed-signal architectures being capable of emulating Zero and First-Order Takagi-Sugeno algorithms. In the realized prototypes, signal processing is carried out in the analog domain whereas the system parameters and configuration are digitally programmable. The applied vii

viii testing strategy was oriented to characterize the DC and transient behaviors of the controllers as well as the statistic spreading between samples. Finally, in the third part, a real-time application of Fuzzy Logic is undertaken in the Analog Signal Processing field: a knowledge-based technique for time-domain signal analysis is discussed. The general idea consists in building an "on-chip oscilloscope", which, based on Fuzzy Logic, could infer assertions that can be used for adaptation, testing, detection, etc. This technique has been used in a digital equalization system based on the Eye Pattern. For this purpose, a preliminary prototype comprising the Fuzzy Controller and the equalizing filter has been fabricated and tested whereas the methodology has been validated by simulations for cable equalization. This book results from the first author's PhD thesis. It is mainly addressed to researchers, undergraduate and postgraduate students working in the field of analog VLSI implementation of Fuzzy Systems and their applications. However, the analysis and synthesis of the circuits presented herein is wide-ranging. Their use exceeds the topic of Fuzzy Logic since they can also be employed in other kind of applications in the field of Analog Signal Processing (i.e. Neural Networks, Non-Linear and Linear Adaptive Filtering, Analog Computation, etc).