طراحي و تنظيم كنترل كننده هاي PID فازي به روش دو مرحله اي براي سيستمهاي خطي چند متغيره تاخير دار

چكيده انگليسي :

Two Level Design and Tuning of Fuzzy PID Controllers for Time Delay Multivariable Linear Systems Mehran Mirzaabolghasem Shirazi mehroonir@yahoo com 13 5 2009 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors Saeed Hosseinnia hoseinia@cc iut ac ir Farid Sheikholeslam sheikh@cc iut ac irAbstractMultivariable processes are found in many industries such as chemical automobile and aerospace Most of theseprocesses have time delay The complex and nonlinear nature of multi input multi output MIMO systems makesmultivariable control a challenging task Multivariable control becomes difficult in the presence of loop interactionswhere different control loops in the system exhibit coupled behavior in the control variables There are manymultivariable control techniques which have been developed to address the above issue including advancedmultivariable control techniques such as model predictive control MPC Among them proportional integralderivative PID control has been the most common in industries Application of fuzzy logic for control problemshas been shown to improve the overall performance significantly Although there are many applications related toSISO based fuzzy PID systems the application design and tuning of fuzzy PID systems for multivariable systemsare less common The adaptive and nonlinear nature of fuzzy control allows fuzzy PID systems to handle nonlinearsystems more efficiently than using linear PID controllers The objective of this thesis is to develop a technique to design and tune PID type fuzzy controllers for multivariableprocess systems Fuzzy PID tuning is performed using the two level tuning principle which was only used for SISOprocesses before In this method the overall tuning is decomposed into two tuning levels low level and high level The low level tuning is dedicated to devise linear gain parameters in the fuzzy PID system and the high level tuningis dedicated to adjust the fuzzy rule parameters Six different fuzzy PID configurations are investigated and thenecessary formulations to perform the two level control for each configuration are obtained These sixconfigurations are compared using four process independent criteria and the most effective one is chosen In the first level two novel analytical methods for calculating linear gains of fuzzy PID controller are presented Theidea of the first method is to bypass continuous infinite spectrum problem by converting a delay process to a rationaldiscrete model and getting back continuous PID controller from its discrete form which is designed with poleplacement In the second method using root locus and Nyquist techniques a dominant pole placement method fordesigning a controller which can reduce interactions among different loops is presented Static and dynamicdecouplers are used for both methods to decouple the loops of the multivariable systems The ability of the proposedmethods in controlling different processes and rejecting disturbance and measurement noise is shown in variousexamples and simulations Recently two criteria for evaluating the ability of fuzzy controllers to produce nonlinear functions are presented Using these criteria six different fuzzy inference systems are compared with each other and the most proper one forperforming the high level control is chosen The high level tuning is performed using a heuristic based method tochange the nonlinearity in the fuzzy output The performance of the final control is evaluated using the controlsimulations of a soil heating process The results are compared with the well known biggest log modulus technique BLT Key WordsPID Control Multivariable Control Two Level Control Fuzzy Control Time Delay Systems

ميرزاابوالقاسم شيرازي، مهران

طراحي و تنظيم كنترل كننده هاي PID فازي به روش دو مرحله اي براي سيستمهاي خطي چند متغيره تاخير دار

كنترل چند متغيره , كنترل دومرحله اي , سيستمهاي تاخيردار