An optimal fuzzy PID controller

This paper introduces an optimal fuzzy proportional-integral-derivative (PI D) controller. The fuzzy PID controller is a discrete-time version of the c onventional PID controller, which preserves the same linear structure of th e proportional, integral, and derivative parts but has constant coefficient yet self-tuned control gains. Fuzzy logic is employed only for the design; the resulting controller does not need to execute any fuzzy rule base, and is actually a conventional PID controller with analytic formulas. The main improvement is in endowing the classical controller with a certain adaptiv e control capability. The constant PID control gains are optimized by using the multiobjective generic algorithm (MOGA), thereby yielding an optimal f uzzy PID controller. Computer simulations are shown to demonstrate its impr ovement over the fuzzy PID controller without MOGA optimization.