STEADY-STATE ANALYSIS OF A 3-TERM FUZZY CONTROLLER

The steady-state response of a fuzzy logic controller is analyzed mathematically, one that uses fuzzy addition as the basis for its decision making process. The nature of the look-up table constructed from fuzzy addition, enabled one to decompose the fuzzy controller into three one-dimensional-multilevel relays. Using the sinusoidal-input describing function technique, the steady-state response of the closed-loop system can be analyzed. The sufficient conditions derived in this paper depend on the parameters of the controller and thus can be used as guidelines to achieve a good step response at steady-state, one that does not lend itself to sustained oscillations or limit cycles.