Using describing function to analyze wriggling phenomenon of fuzzy control systems

In this paper, the describing function of bi-dimensional multi-level relay equivalent model of two-input-single-output fuzzy controller is derived. Based on this function, we analyze the wriggling phenomenon of fuzzy control systems, and qualitatively investigate the effect of fuzzy controller scaling factors on the wriggling amplitude. Simulation result has proved the feasibility and accuracy of the describing function technique in the analysis of fuzzy control systems.