Relay Tuning of PID Controllers

This book presents comprehensive information on the relay auto-tuning method for unstable systems in process control industries, and introduces a new, refined Ziegler-Nichols method for designing controllers for unstable systems. The relay auto-tuning method is intended to assist graduate students in chemical, electrical, electronics and instrumentation engineering who are engaged in advanced process control. The book's main focus is on developing a controller tuning method for scalar and multivariable systems, particularly for unstable processes. It proposes a much simpler technique, avoiding the shortcomings of the popular relay-tuning method. The effects of higher-order harmonics are incorporated, owing to the shape of output waveforms. In turn, the book demonstrates the applicability and effectiveness of the Ziegler-Nichols method through simulations on a number of linear and non-linear unstable systems, confirming that it delivers better performance and robust stability in the presence of uncertainty. The proposed method can also be easily implemented across industries with the help of various auto-tuners available on the market. Offering a professional and modern perspective on profitably and efficiently automating controller tuning, the book will be of interest to graduate students, researchers, and industry professionals alike.

Auteur

M. Chidambaram is currently a Professor at the Department of Chemical Engineering, Indian Institute of Technology in Madras, Chennai. After completing his PhD at the Indian Institute of Science in Bangalore he served as a faculty member at the Indian Institute of Technology Bombay, Mumbai, from 1984 to 1991. Since then he has been a faculty member at the Indian Institute of Technology in Madras. He has also served the institute as Head of the Department of Chemical Engineering from 2000 to 2003 and as the Director, National Institute of Technology (NIT), Tiruchirappalli from 2005 to 2010. He has 190 journal articles, 7 books and 4 book chapters to his credit. His primary research interest is in the area of process control. 'Nikita Saxena completed her PhD' under the guidance of Prof. M Chidambaram. She completed her degree (BTech) in Chemical Technology at Harcourt Butler Technical Institute (HBTI), Kanpur. She also has a year of experience in the fast-moving consumer goods (FMCG) industry. She has authored 4 journal articles and presented papers at several conferences. Her areas of interest include relay control systems and model identification.

Contenu
LIST OF TABLES

LIST OF FIGURES

ABBREVIATIONS

NOTATIONS

PREFACE

Chapter 1 Introduction

1.1. Scope of process control 1.2. Proportional Integral Derivative Control

1.3. Loop tuning

1.4. Relay feedback Technique &nbs p;

1.5. Real time applications

1.6. Conclusion

Chapter 2 Relay feedback control

2.1 Relay control system classification

2.2 Describing function analysis

2.3 Relay auto-tuning for scalar systems

2.3.1 Modified relay feedback method - Sung et. al. (1995)

2.3.2. Modified Fourier series analysis of process response - Srinivasan & Chidambaram (2004)

2.3.3. Use of preload relay - Tan et. al. (2006)

2.3.4. Enhanced process activation method - Je et. al. (2009)

2.3.5. Simulation study 2.4 Relay auto-tuning of multivariable systems

2.4.1. Pairing criteria

2.4.2. Condition for limit cycle to occur

2.5. Relay feedback test for multivariable systems

2.5.1. Relay auto-tuning of decentralized controllers

2.5.1.1. Palmor et. al. (1994)

2.5.1.2. Zhuang and Atherton (1994) 2.5.1.3. Campestrini et. al. (2006)

2.5.2. Relay auto-tuning of centralized controller

2.5.2.1. Menani and Koivo (1996c)

2.5.2.2. Wang et. al. (1997)

2.5.2.3. Menani (1999)

2.6. Design of PID controllers

2.7. Robustness stability analysis

2.8. Conclusion ;

Chapter 3 Auto Tuning of Unstable SOPTD Systems

3.1 Introduction

3.2 Consideration of higher order harmonics

3.2.1. Problem 1

3.2.2. Problem 2 3.2.3. Problem 3

3.3 Measure of robust performance

3.4 Design Procedure&nb sp;

3.4.1 Tuning rule

3.4.2 Simple method to calculate Kc,min

3.5 Simulation studies 3.5.1 Example 1

3.5.1.1 Effect of measurement noise

3.5.2 Example 2

3.5.3 Example 3

3.5.4 Example 4: Unstable Non-linear Bioreactor

3.5.4.1 Effect of measurement noise

3.6 Conclusions

Chapter 4 Decentralised PID Controllers for stabl e system

4.1 Introduction 4.2 Design procedure

4.3 Simulation study on stable systems

4.3.1 Example 1

4.3.1.1 Effect of measurement noise

4.3.2. Example 2

4.3.3. Example 3 4.3.4. Example 4

4.4 Conclusions

Chapter 5 Decentralised PID Controllers for unstable system

5.1. Introduction

5.2. Design procedure

5.3. Simulation study on unstable systems

5.3.1 Example 1 5.3.1.1 Calculation of Kc,min

5.3.1.2.Calculation of Kc,max

5.3.2. Example 2

5.3.2.1 C alculation of Kc,min

5.3.2.2.Calculation of Kc,max

5.3.3. Example 3

5.3.3.1. Calculation of Kc,min

5.3.3.2.Calculation of Kc,max <p&gt...