Aspects of fuzzy logic in controller design

Fuzzy logic is a systematic mathematical formulation for investigating and characterizing the different types of uncertainties. This paper presents the concept of representing uncertainties in membership diagram and forming the fuzzy rules (fuzzification) specifically for the basic design of controller. The fuzzification is carried out with eleven linguistic values. A defuzzification approach developed in this paper is novel and achieves better stability. The defuzzification rule is used to determine the relevant control signal for each sampling instant. Simulation results for the system having one and two poles at the origin are presented to demonstrate the better performance of the fuzzy controller