Investigating and developing robust PID controller design techniques

ABSTRACTM.S. ThesisINVESTIGATING AND DEVELOPING ROBUST PID CONTROLLERDESIGN TECNIQUESFato Yıkannönü UniversityGraduate School of Natural and Applied SciencesDepartment of Electrical and Electronics Engineering135+x pages2005Supervisor: Doç. Dr. Nusret TanPID controllers are used extensively in industries because of their robust performance andsimplicity. This controller structure has three parameters namely proportional gain ( K p ) ,integral gain ( K i ) and derivative gain ( K d ) . Tuning of these parameters for a given controlsystem is the most important requirement when designing PID controllers. Several methodsfor designing PID controllers have been developed. Although, these methods have manyadvantages, they also have some disadvantages. Therefore, tuning of the parameters of PIDcontroller is still an active research area.The aim of this thesis is to investigate some of the methods related to the design of PIDcontrollers and obtain new robust design techniques. Design of robust PID controller isespecially important for real applications which have parameter uncertainities. Because,parameter uncertainty in the systems is an unavoidable fact. Therefore, obtaining a desiredcontrol besides uncertainty in systems is important.In the thesis, it has been shown that PI and PID controllers which stabilize a controlsystem can be determined using the stability boundary locus method. Related simulationstudies have been done. The method has also been applied to the PI-PD controllerstructure and very promising results have been obtained. Thus, a robust design technique forPI-PD controller has been developed. PI-PD controller structure has more advantagesthan PID controller structure especially for unstable, resonant and integrating processes.To obtain the results given in the thesis, required programs have been prepared in theMATLAB environment. The results developed in these research work, have potential featuresto be used for practical applications. It is also possible to extend these results to othercontroller structures.KEYWORDS: Stability, controller, PID controller, PI controller, stability region, parameter,step response, performance