Application of fuzzy logic control system for regulation of differential pressure in Liquid Zone Control System

In this paper, fuzzy control scheme has been proposed for generating regulating signals to feed and bleed control valves, which are used in Liquid Zone Control System (LZCS) for maintaining constant pressure difference between gas outlet header and delay tank. The LZCS and the existing PI controller are briefly described. It is followed by the design of Fuzzy Controller. It consists of seven symmetric triangular input membership functions and output membership functions each. Mamdani implication has been used to infer output contribution from each rule. The centroid type of defuzzification method is employed to get the crisp output values. The fuzzy logic controller for feed and bleed control valves so designed has been validated by performing a variety of experiments on a full scale LZCS test setup at Bhabha Atomic Research Centre and its performance is analyzed and compared to that obtained with existing PI controller. In comparison with the existing PI controller, the fuzzy logic controller's performance is superior in all cases considered.