Fuzzy Model Reference Adaptive Control System

Abstract: – When using the Lyapunov synthesis approach to construct a stable fuzzy control system, one important way is to regard the fuzzy systems as approximators to approximate the unknown functions in the system to be controlled. Concerning the unknownness of the unknown functions, generally there are two cases: a completely unknown case, and a partly unknown case. However, most of the schemes presented so far have only focused on the former. Clearly, if an unknown function belongs to the latter, the knowledge available about the function should be utilized as much as possible in the development of the control system. In this paper, our goal is to design a fuzzy controller for a class of model reference adaptive systems with uncertainties, which can correspond to the either case. Also, we propose a unique way to deal with the uncertainties, i.e., adopt a switching function with an alterable coefficient, which is tuned by adaptive law based on the tracking error. Key-Words: – Lyapunov function, fuzzy approximator, MRACS, stability, adaptive law.