A simple adaptive fuzzy logic controller base on shifting of the membership function

Abstract

This paper introduces an Adaptive Fuzzy Logic Control (AFLC) for dynamic system. The parameters to be adjusted are the universe of discourse (UOD). The modification also performed by the adaptation mechanism shifts the membership function (MF) for both input and output. According to a continuous measurement, the parameters of the controller are self-tuned. An AFLC has been used to improve the dynamic response and steady state performance of the controlled dynamical system. An approach similar to PID controller is adapted as the adjustment mechanism to minimize the error and brings it to zero. In this paper, the principles for tuning UOD of the input and output are proposed. The parameters of the controller have been adjusted on-line and tested for various operating conditions such as varying gain, noise, disturbance and delay. The simulation results indicate that output response of AFLC has better tracking performance compared to FLC controller. Moreover, it manages to stabilize the system and sustain relatively good response.