Ph.D. Programs

Doctoral Dissertation

Assumption University
Bangkok, Thailand
November 1996

GENETIC-BASED SELF-TUNING CONTROLLER
by
Pataya Dangprrasert


A doctoral dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computer and Engineering Management.

Examination Committee :
Prof. Dr. Srisakdi Charmonman
Assoc.Prof. Somchai Tayarnyong
Air Marshal Dr.Chulit Meesajjee
Dr.Suphamit Chittayasothorn
Dr.Pornchai Phutlek
Dr.Prapon Phasukyud
Dr.Aran Namphol
Dr.Vichit Avatchanakorn

Name :
Pataya Dangprasert

Nationality :
Thai

Previous Degree :
Master of Sciences in CIS
Assumption University, Thailand

Bachelor of Sciences (Pharmacy)
Oregon State University,USA

Bachelor of Sciences (Gen.Sciences)
Kasetsart University, Thailand


Approval Page

RESEARCH TITLE 	: GENETIC-BASED SELE-TUNING CONTROLLER
CANDIDATE NAME 	: Pataya Dangprasert
ADVISOR NAME    : Dr.Vichai Avatchanakorn
ACADEMIC YEAR  	: 1996
The Graduate School of Assumption University had approved this dissertation as a partial fulfillment of the requirement for the degree of Doctor of Philosophy in Computer and Engineering Managemant


Abstract

Recently,the replacement of intelligent control in place of conventional control has increased due to the latter often failing to detect changes in adaptive environment. Among various intellgence control concepts, self-tuning regulator (STR) seems to be the most practical to implement. However, the success of STR has been laid on recursive off-line methods which are local search schemes based on a gradient-following technique.

Genetic algorithms (GAs) are search techiques based on natural genetic evolution.By simulating evolutionary process, GAs can bring the power of population genetics to provide autonomous search for artificial systems. They have been used as general-purpose optimization methods that can avoid local optima.

This research brings the adaptive search power of GAs and combines it with the concept in controller design provided by STR to propose a new intelligent controller, the genetic-based self-tuning controler. In STR controller design approach, the controller is separated into estimator loop and regulator loop. Genetic-based self-tuning controller uses GAs as parameter identifying scheme in estimator loop and uses the single-input single-output model to represent the process dynamics of a controlled system for designing the regulator.

Results of computer simulations by using load frequency control (LFC) of the power system as a domain problem, show efficient and robust control power of genetic-based self-tuning controller as an on-line parameter identification without any prior input-output knowledge. It is also capable of controlling a system with non-linearity characteristics.


Acknowledgements

I express my sincere appreciation to my advisor, Dr. Vichit Avatchanakorn,for his continuous advice, guidance,and support. His profound knowledge and kindness will always be an inspiration.

Thanks are also due to Prof. Dr.Srisakdi Charmonman for founding the Ph.D.Programs at ABAC. He was the first one who cncouraged me to apply to this program and he further provided valuable advice throughout my study.

Many thanks are extended to Associate Professors Somchai Tayarnyong, Air Marshall Dr. Chulit Meesajjee, Dr. Suphamit Chittayasothorn, Dr.Prapon Phasukyud,Dr.Aran Namphol, and Dr.Pornchai Phutlek for their careful reading of this manuscript,and to Dr.Boonmark Sirinaovakul for serving on my qualifying examination committee. Their constructive and valuable comments have made this work better in various aspects.

I am grateful to Rev. Dr.Prathip M.Komolmas, (AU president) for his constant encouragement.

The friendship and encouragement of my fellow colleagues, Ms. Pornthip Archadej, and Ms.Somsong Chirapahanakul have been important forces in my study. Special thanks to Dr.Kamales Santivejkul for his kind words of advice,and my friend, Ms. Nalinee Nandhabiwat, for her time in second language tutorials. Thanks are also to Mr.Uttrawooth Narknisorn for his support.


Table of Contents

List of Figures
list of Table
Nomenclatures

Chapter 1 : Introduction

Chapter 2 : Genetic Algorithms
2.1 Introduction
2.2 Simple Genetic Algorithms
2.3 Genetic Algorithms Applidations
2.4 Conclusions

Chapter 3 : Design of a Genetic-Based Self-Tuning Controller
3.1 Introduction
3.2 Controller Design
3.3 Self-Tuning Regulator
3.4 Genetic-Based Self-Tuning Controller Design
3.4.1 Conceptual Fundamentals of the Genetic-Based Self-Tuning Controller
3.4.2 Operational Aspect of the Genetic-Based Self-Tuning Controller
3.5 Conclusions

Chapter 4 : Application to a Load Frequency Control System
4.1 Introduction
4.2 Background of the Problem Domain-LFC
4.3 Application to One-Area LFC System
4.3.1 Designing Genetic-Based Self-Tuning Load Frequency Controller
4.3.2 Sensitivity Analysis
4.3.3 Output Responses
4.4 Application to Two-Area Interconnected LFC System
4.5 Conclusions

Chapter 5 : Conclusion and Recommendations
5.1 Conclusions
5.2 Recommendations

Appendix A : Schemata Theorems
Appendix B : Load Frequency Control Model
Appendix C : Runge-Kutta Methods
References

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