Modeling and Advanced Control for Process Industries Applications to Paper Making Processes Other titles published in this Series: Parallel Processing for Jet Engine Control Haydn A. Thompson Iterative Learning Control for Deterministic Systems Kevin L. Moore Parallel Processing in Digital Control D. Fabian Garcia Nocetti and Peter J. Fleming Intelligent Seam Tracking for Robotic Welding Nitin Nayak and Asok Ray Identification of Multivariable Industrial Processes for Simulation, Diagnosis and Control Yucai Zhu and Ton Backx Nonlinear Process Control: Applications of Generic Model Control Edited by Peter L. Lee Microcomputer-Based Adaptive Control Applied to Thyristor-Driven D-C Motors Ulrich Keuchel and Richard M. Stephan Expert Aided Control System Design Colin Tebbutt Ming Rao, Qijun Xia and Yiqun Ying Modeling and Advanced Control for Process Industries Applications to Paper Making Processes With 115 Figures Springer-Verlag London Berlin Heidelberg New York Paris Tokyo Hong Kong Barcelona Budapest Ming Rao, PhD Qijun Xia, PhD, MSc, BSc Yiqun Ying, MSc, BSc Department of Chemical Engineering University of Alberta 536 Chemical-Mineral Engineering Building Edmonton, Canada T6G 2G6 ISBN-13: 978-1-4471-2096-4 e-ISBN-13: 978-1-4471-2094-0 DOl: 10.1007/978-1-4471-2094-0 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of repro graphic reproduction in accordance with the terms of licences issued by the Copyright Licensing Agency. Enquiries concerning reproduction outside those terms should be sent to the publishers. © Springer-Verlag London Limited 1994 Softcover reprint of the hardcover I st edition 1994 The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. 69/3830-543210 Printed on acid-free paper PREFACE The paper machine is a very important part of pulp and paper manufac turing processes. Process modeling and control play key roles in the paper machine operation. Due to the complexity of the process oper ation and the requirements of high quality product, low cost production, safety and environment protection, more and more pulp and paper companies are looking for advanced control technology to improve their process operation. This book reports our research results on the modeling and advanced control for paper machines. Both theoretic fundamentals and industrial applications are presented. This is a book in which all the advanced technologies in modeling and control discussed are focused on applica tions to paper machines. The book is organized as follows: Chapter 1 gives a brief introduction to paper making process fundamentals and an overview of paper machine control. Various process dynamics analysis and modeling techniques are discussed in detail in Chapter 2. Based on the characteristics of paper machine operation, some typical advanced control strategies, such as robust control (Chapter 3), predictive control (Chapter 4), bilinear control (Chapter 5), fault-tolerant control (Chap ter 6) and their design and implementation techniques as well as real industrial applications are presented. Since model-based control systems cannot handle the ill-formulated problems involved in paper machines, fuzzy control (Chapter 7), expert systems (Chapter 8), artificial neural networks (Chapter 9) and intelligent on-line monitoring and control systems (Chapter 10) are then introduced. Their applications to process control, control system design, process modeling and product quality prediction, and on-line monitoring and control for paper and pulp processes are also presented. It should be pointed out that not all the control technologies applied to paper machines have been covered in this book. Some important applications, such as cross-machine direction (CD) control, are not included. This book is designed as a reference book for engineers and research scientists who work on process control, especially in the pulp and paper industry. It can also be used as a textbook for graduate student courses on process modeling and advanced process control in universities. We hope that this book will help to narrow the gap between academic research and industry application, and to reduce the barriers that exist in applying advanced control technologies to real industrial processes. SERIES EDITOR'S FOREWORD The series Advances in Industrial Control aims to report and encourage technology transfer in control engineering. The rapid development of control technology impacts all areas of the control discipline. New theory, controllers, actuators, sensors, new industrial processes, com puting methods, applications, philosophies, ... new challenges. Much of this development work resides in industrial reports, feasibility study papers and the reports of advanced collaborative projects. The series offers an opportunity for researchers to present an extended exposition of such new work in all aspects of industrial control for wider and rapid dissemination. It is always valuable to welcome to the Series a text which deals with the control problems of one individual sector. Dr Rao and his colleagues have developed an Intelligent Online Monitoring and Control System (lOMCS) for pulp and paper making process control applications. In this volume, the background research and the development path for the IOMCS is presented. It is a route which takes in process model developments, advanced control methods and methods like fuzzy control before arriving at the integrated construction of the IOMCS. The whole development is underpinned by the technological framework of a plant wide distributed control system. For this reason, the concept of an IOMCS has a wider applicability to general process control engineering. We hope the volume will be read with interest by this broader audience of control, manufacturing, process and even production engineers. M. J. Grimble and M. A. Johnson Industrial Control Centre, University of Strathclyde, Scotland, U.K. Professor M.J. Grimble and Dr M.A. Johnson, editors of the Advances in Industrial Control Series, provided us with very important suggestions and assistance in preparing this book. Professor Y. Sun and Professor C. Zhou of Zhejiang University gave us the valuable suggestions, allowed us to use the research results from their Institute. We gratefully acknowledge Dr P. Li and Dr Q.G. Wang for their important contributions to Chapter 3 and Chapter 7. Professor H. Qiu, Professor L. Peng and Dr X. Shen helped us by reviewing the manuscript, and providing many useful comments for improvement of the book. Graduate students, H. Fazadeh, J. Sun and J. Zurcher and Dr Q. Wang provided technical support to the content of this book. We would like to express our appreciation for their help and contributions. We also gratefully acknowledge the financial and technical support of the Natural Sciences and Engineering Research Council of Canada, Canadian Pulp and Paper Association, Weyerhaeuser Canada Grande Prairie Operations, Slave Lake Pulp Corporation, DMI Peace River Pulp Division, MoDo Chemetics, Perde Enterprise, and Canada Alberta Partnership on Forestry. MingRao Qijun Xia Yiqun Ying Edmonton, Canada October 31, 1993 TABLE OF CONTENTS 1 Background . . . . . . . . . . . . . . . . 1 1.1 Paper Making: Process Fundamentals. 1 1.2 Paper Machine Control Problems 5 1.3 References .............. . 14 2 Process Dynamics and Modeling 17 2.1 Introduction . . . . . . 17 2.2 Pressurized Headboxes 19 2.3 Open Headbox . 30 2.4 Wire and Press . . . . . 35 2.5 Drying Section . . . . . 39 2.6 Model Accuracy Test and Conclusions 49 2.7 References............... 51 3 Robust Control 53 3.1 Introduction . . . . . . . . . 53 3.2 Multi-model Robust Control. 54 3.3 Conclusions 68 3.4 References . . . 69 4 Predictive Control . 71 4.1 Adaptive Fading Kalman Filter 71 4.2 Adaptive Predictive Control . 88 4.3 Model Algorithmic Control 102 4.4 Conclusions 118 4.5 References . . 119 5 Bilinear Control . 123 5.1 Introduction . . . . . . . . . 123 5.2 Bilinear Decoupling Control . 125 5.3 Bilinear State Observers . . . 136 5.4 Bilinear Suboptimal Control. 146 5.5 Conclusions 153 5.6 References ......... . 154 6 Fault-Tolerant Control . . . . . . . . . 157 6.1 Introduction ............ . 157 6.2 Fault-tolerant Control of Headboxes 159 6.3 Fault-tolerant Control of Drying Section 174 6.4 Conclusions 188 6.5 References 189 7 Fuzzy Control 193 7.1 Fuzzy Optimal Control 193 7.2 Fuzzy-Precise Combined Control 201 7.3 Conclusions 211 7.4 References. 213 8 Expert Systems 215 8.1 Introduction to Expert Systems 216 8.2 IDIS for Process Control System Design 221 8.3 Application to Headbox Control System Design 233 8.4 Conclusions 242 8.5 References ............ . 243 9 Modeling via Artificial Neural Network 245 9.1 Introduction ........... . 245 9.2 Fundamentals of Artificial Neural Network 248 9.3 Backpropagation Learning Paradigm 251 9.4 Application to Paper Machine . 254 9.5 Conclusions 262 9.6 References .......... . 262 10 IOMCS for Pulp and Paper Processes 265 10.1 Introduction .......... . 266 10.2 System design and implementation . 267 10.3 Conclusions. 288 10.4 References 290 Index ..... . 293 EDITORIAL BOARD Professor Dr -Ing J.Ackermann Professor H. Kimura DLR Institut fur Robotik und Professor of Control Engineering Systemdynamik Department of Mechanical Postfach 1116 Engineering for Computer D-82230 WeSling Controlled Machinery Germany Faculty of Engineering Osaka University Professor I. D. Landau 2-1 Yamadaoka Le Directeur Suita Laboratoire d' Automatique de Osaka 565 Grenoble Japan ENSIEG, BP 46 38402 Saint Martin d'Heres Professor A. J. Laub France Professor and Chairman Department of Electrical and Dr D. C. McFarlane Computer Engineering BHP Research University of California Melbourne Research Laboratories Santa Barbara 245-273 Wellington Road California 93106 Mulgrave U.S.A. Victoria 3170 Australia Professor J. B. Moore Professor B. Wittenmark Department of Systems Department of Automatic Control Engineering Lund Institute of Technology The Australian National PO Box 118 University S-221 00 Lund Research School of Physical Sweden Sciences GPO Box 4 Dr D. W. Clarke, MA., D.Phil, Canberra CEng, FlEE ACT 2601 Reader in Information Australia Engineering Department of Engineering Professor Dr -Ing M.Thoma Science Institut Fur Regelungstechnik University of Oxford Universitat Hannover Parks Road Appelstrasse 11 Oxford, OX1 3PJ D-30167 Hanover 1 U.K. Germany