1、Advanced Control UnleashedPlant Performance Managementfor Optimum BenefitAdvanced ControlUnleashedPlant Performance Managementfor Optimum BenefitTerrence L. BlevinsGregory K. McMillanWilly K. WojsznisMichael W. BrownNoticeThe information presented in this publication is for the general education of
2、the reader. Because neither the author nor the publisher have any control over the use of the information by the reader, both the author and the publisher disclaim any and all liability of any kind arising out of such use. The reader is expected to exercise sound professional judgment in using any o
3、f the information presented in a particular application.Additionally, neither the author nor the publisher have investigated or considered the affect of any patents on the ability of the reader to use any of the information in a particular application. The reader is responsible for reviewing any pos
4、sible patents that may affect any particular use of the information presented.Any references to commercial products in the work are cited as examples only. Neither the author nor the publisher endorse any referenced commercial product. Any trademarks or tradenames referenced belong to the respective
5、 owner of the mark or name. Neither the author nor the publisher make any representation regarding the availability of any referenced commercial product at any time. The manufacturers instructions on use of any commercial product must be followed at all times, even if in conflict with the informatio
6、n in this publication.Copyright 2003 ISA The Instrumentation, Systems, and Automation SocietyAll rights reserved. Printed in the United States of America. 10 9 8 7 6 5 4 3 2ISBN 1-55617-815-8No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any me
7、ans, electronic, mechanical, photocopying, recording or otherwise, without the prior writ-ten permission of the publisher.ISA67 Alexander DriveP.O. Box 12277Research Triangle Park, NC 27709Library of Congress Cataloging-in-Publication Data is in process.DedicationThis book is dedicated to Karen Blev
8、ins, Cathy MacDonell Brown,Carol McMillan, and Susan Wojsznis who have provided encouragement and support throughout our careers.viiContentsACKNOWLEDGEMENT xiiiABOUT THE AUTHORS xvFOREWORD xviiChapter 1 INTRODUCTION 1Chapter 2 SETTING THE FOUNDATION 5Practice, 5Overview 5Opportunity Assessment 12Exa
9、mples 15Application, 20General Procedure 20Application Detail 26Rules of Thumb 74Theory, 76Process Time Constants and Gains 76Process Time Delay 79Ultimate Gain and Period 80Peak and Integrated Error 82Feedforward Control 84Dead Time from Valve Dead Band 84Nomenclature, 85References, 86viii Advanced
10、 Control UnleashedChapter 3 APC PATHWAYS 89Practice, 89Overview 89Opportunity Assessment 94Examples 103Application, 106General Procedure 106Application Detail 108Rules of Thumb 115References, 116Chapter 4 EVALUATING SYSTEM PERFORMANCE 119Practice, 119Overview 119Opportunity Assessment 121Examples 12
11、5Application, 129General Procedure 129Application Details 131Rules of Thumb 143Guided Tour 144Theory, 147Using Statistics for Control Performance Evaluation 150Extending the Concept to the Multi-variable Environment 153Addressing Advanced Control 154Diagnostic Tools 156References, 160Chapter 5 ABNOR
12、MAL SITUATION MANAGEMENT 163Practice, 163Overview 163Opportunity Assessment 165Examples 166Application, 168General Procedure 168Application Details 169Rules of Thumb 171Guided Tour 173Theory, 177Introduction to Expert Systems 177Rules 178Inference Engine 180Facts 181References, 182Table of Contents
13、ixChapter 6 AUTOMATED TUNING 183Practice, 183Overview 183Opportunity Assessment 185Examples 187Application, 197General Procedure 197Application Detail 200Rules of Thumb 202Guided Tour 206Theory, 208Introduction to Auto Tuners 208Basics of Relay-Oscillation Tuning 210Model Based Tuning 218Robustness
14、Based Tuning 221Adaptive Control 225References, 237Chapter 7 FUZZY LOGIC CONTROL 239Practice, 239Overview 239Opportunity Assessment 240Examples 240Application, 241General Procedure 241Rules of Thumb 242Guided Tour 242Theory, 244Introduction to Fuzzy Logic Control 244Building a Fuzzy Logic Controller
15、 247Fuzzy Logic PID Controller 251Fuzzy Logic Control Nonlinear PI Relationship 254FPID and PID Relations 257Automation of Fuzzy Logic Controller Commissioning 258References, 259Chapter 8 PROPERTIES ESTIMATION 261Practice, 261Overview 261Opportunity Assessment 263Example Dynamic Linear Estimator 265
16、Examples Neural Networks 269Application, 274General Procedure 274Application Detail 279x Advanced Control UnleashedRules of Thumb 289Guided Tour 289Theory, 294Dynamic Linear Estimator 294Neural Networks 296References, 305Chapter 9 MODEL PREDICTIVE CONTROL 307Practice, 307Overview 307Opportunity Asse
17、ssment 310Examples 316Application, 337General Procedure 337Application Detail 339Rules of Thumb 353Guided Tour 355Theory, 362The Basics of Process Modeling 364Identifying the Process Model 367Unconstrained Model Predictive Control 369Integrating Constraints Handling, Optimization and Model Predictiv
18、e Control 373References, 381Chapter 10 VIRTUAL PLANT 383Practice, 383Overview 383Opportunity Assessment 386Examples 387Application, 389General Procedure 389Online Adaptation 393Application Detail 395Rules of Thumb 399Guided Tour 400Theory, 403References, 408Appendix A ADDITIONAL OPPORTUNITY ASSESSME
19、NT QUESTIONS 409Appendix B BATCH-TO-CONTINUOUS TRANSITION 415Appendix C DEFINITIONS 419Table of Contents xiAppendix D TOP 20 MISTAKES 425INDEX 431xiiiAcknowledgementThe authors wish to express their appreciation to Mark Nixon and Ron Eddie from Emerson Process Management, for their enthusiastic supp
20、ort and commitment of resources for this book, to Jim Hoffmaster, Bud Keyes, Duncan Schleiss, John Berra, and Gil Pareja from Emerson Process Man-agement for their inspiration and support in establishing the DeltaV advanced control program, to Karl Astrom from Lund University, Tom Edgar from the Uni
21、versity of Texas at Austin, Dale Seborg from the University of California, Santa Barbara and Tom McAvoy from the Univer-sity of Maryland for their guidance in the pursuit of new technologies, Mike Gray and Mark Mennen from Solutia Inc. for the initiation and sustenance of advanced control applicatio
22、ns and innovations, Ken Schibler from Emerson Process Management for his help in setting the direction of the book, Robert Cameron, Michael Mansy, Glenn Mertz, and Gina Underwood from Solutia Inc. for their valuable comments, and finally, Scott Weidemann from Washington University, and Jim Cahill, B
23、renda Forsythe, and Cory Walton from Emerson Process Management for their essential contributions to the videos and demos on the CD. The authors extend their thanks to the developers of the advanced control tools that were the inspiration for this book. This includes Vasiliki Tzovla, Ron Ottenbacher
24、, Dirk Thiele, Ashish Mehta, Yan Zhang, Peter Wojsznis, John Gudaz, Ian Nadas and Mei Yang. Also, we would like to recognize the valuable contribution of Tom Aneweer, Dennis Stevenson, Jay Colcla-zier, Darrin Kuchle, Dick Seemann, Joe S. Qin, Steve Morrison, Mike Ott, and Sai Ganesamoorthi.The disci
25、pline of Process Control and Advanced Process Control is an exciting, challenging and rewarding field of engineering. Some of us moved into this discipline by chance, while others made a conscious deci-sion to become Process Control Engineers. Regardless of our entry point or motivation, we all appr
26、eciate the fact that engineers before us took the time and effort to teach us the tools and techniques that allowed us to achieve success. This book passes along the knowledge of many years and many people and acknowledges the efforts of our engineering mentors. We hope it will allow others not only
27、 to benefit from all the experience we have benefited from so greatly but also to take the technology to the next level.xvAbout theAuthorsTerrence L. Blevins has been actively involved in the application and design of process control systems throughout his career. For over fifteen years, he worked a
28、s a systems engineer and group manager in the design and startup of advanced control solutions for the pulp and paper industry. Terry was instrumental in the establishment of Emerson Process Manage-ments Advanced Control Program. He is the Fieldbus Foundation team leader for the Function Block Speci
29、fication. In this capacity, Terry is involved in the movement of Fieldbus Foundation function block work into international standards. Terry is the US expert to the IEC TC65 WG6 and SC65C WG7 function block committees. He wrote the fieldbus section included in the Process/Industrial Instrumentation
30、and Controls handbook. Terry has eight patents and has written over forty papers on process con-trol system design and applications. He received a BEE from the Univer-sity of Louisville in 1971 and a Master of Science degree in Electrical Engineering from Purdue University in 1973. Presently, Terry
31、is a principal technologist in DeltaV Product Engineering and the team leader for DeltaV advanced control product development.Phone: (512) 418-4628E-mail: terry.blevinsEmersonPGregory K. McMillan retired as a Senior Fellow after a 33 year career with Monsanto and Solutia Inc, where he specialized in
32、 improving loop perfor-mance, controller tuning, valve dynamics, opportunity assessments, dynamic simulation, fermentor control, pH control, and reactor control. Greg is the author of numerous articles and books, his most recent book being: Good Tuning A Pocket Guide. He has contributed to several h
33、and-books and is the editor of the Process/Industrial Instrumentation and Controls handbook and the coauthor of a monthly column titled “Control Talk”. xvi Advanced ControlGreg is an ISA Fellow and received the ISA “Kermit Fischer Environmen-tal” Award for pH control in 1991, the Control Magazine “E
34、ngineer of the Year” Award for the Process Industry in 1994, and was one of the first inductees into the Control Magazine “Process Automation Hall of Fame” in 2001. He received a B.S. from Kansas University in 1969 in Engineering Physics and a M.S. from University of Missouri Rolla in 1976 in Contro
35、l Theory. Presently, Greg is an affiliate Professor at Washington University in Saint Louis, Missouri and is a consultant through EDP Contract Services in Austin, Texas.Cell Phone: (314) 703-9981E-mail: Willy K. Wojsznis has been involved in developing advanced control products over the last twelve
36、years focusing on model predictive control and auto tuning. Over the previous nearly 25-year of his career he was developing computer control systems and applications in cement, steel, mining and paper industries. His professional work resulted in a number of successful and innovative advanced contr
37、ol products, fourteen patents, and above thirty technical papers. He received control engineering degree (EE) from Kiev Technical University in1964, M.S. in Applied Mathematics from Wroclaw University in 1972, and Ph.D. from Warsaw University of Technology in 1973. Presently, Willy is a part of Delt
38、aV advanced control group. He conducts applied research in the areas of optimization, adaptive control and model predictive control.Phone: (512) 418-7475E-mail: willy.wojsznisEmersonPMichael W. Brown has spent his entire career in the application of Advanced Process Control technologies in the conti
39、nuous processing industries. Over the previous 15 years of his career, he has served as an Advanced Process Control Consultant, providing implementation exper-tise and technology guidance for many operating companies. His exten-sive knowledge and experience in the areas of model based predictive con
40、trol and real-time optimization have assisted many companies in cap-turing the benefits of these performance improvement technologies. His work has resulted in several technical papers, published in various control journals. Michael is a Chemical Engineer, received a B.A.Sc. from the Uni-versity of
41、Waterloo in 1987 and completed his Masters in Applied Science in 1989. Presently, Michael is the Applications Business Manager, with Matrikon Inc., where he continues to work with industry to bring Advanced Control Technology to the next level.Phone: (905) 282-9248E-mail: xviiForewordThere has been
42、a dynamic development of control over the past 50 years. Many new methods have appeared. The methods have traditionally been presented in highly specialized books written for researchers or engineers with advanced degrees in control theory. These books have been very use-ful to advance the sate of t
43、he art. They are however difficult for an average engineer. The reasons are that it is necessary to read many books to get a good coverage of advanced control techniques and that the level of mathe-matics used requires a substantial preparation. This is a dilemma because several of the advanced cont
44、rol techniques have indeed been very benefi-cial in industrial and more engineers should be aware of them. Even if many details of the new methods are complicated the basic underlying ideas are often quite simple. Many methods have also been packaged so that they are relatively easy to use. It is th
45、us highly desirable to present the industrially proven control methods to ordinary engineers working in industry. This book is a first attempt to do this. The book provides a basis for assessing the benefits of advanced control. It covers auto-tuning, model predictive control, optimization, estimato
46、rs, neural networks, fuzzy control, simulators, expert systems, diagnostics, and performance assess-ment. The book is written by four seasoned practitioners of control, hav-ing jointly more than 100 years of real industrial experience in the development and use of advanced control. The book is well
47、positioned to provide the bridge over the infamous Gap between Theory and Practice in control. Karl J. Astrom11IntroductionThe advent of powerful and friendly integrated software has moved advanced process control (APC) from the realm of consultants into the arena of the average process control engi
48、neer. The obstacles of infrastruc-ture and special skill requirements have started to disappear and we are poised for an accelerated application of APC. It is well known that APC seeks to discover, incorporate, and exploit knowledge about raw materials, process, product, equipment, instrumen-tation,
49、 and final elements. What is not often recognized is the significant increase in the knowledge base of both plant and field operations that occurs as the APC system is developed. In fact, an appreciable portion of the benefits are achieved by improvements made in operating procedures, set points, sensors, and control valves as a result of the methodical analy-sis, testing, modeling, and prototyping that are part of the best practices used in the implementation of APC systems. Until recently, most of this kn
