Improved Performance of SOPDT Process using Rule Base Shifting Scheme for Fuzzy PI Controller

Rule Base is one of the key factors in design of fuzzy controller. The performance of the system is affected if a delay element is present in the system. The significance of the proposed method is tested on different second order plus delay time process (SOPDT) models using modified rule bases. A criterion is developed for selection of rule base depending on amount of delay time and time constant of the process and is given in tabulated form. The graphical results are given to show the improved process performance using proposed method. Robustness of the proposed method is checked by applying disturbance and set-point change. Analytical comparison with the existing methods is given using performance indices integral of square error (ISE), integral of absolute error (IAE) and integral of time absolute error (ITAE).