ABSTRACT
The stability property of a control system is an important issue that must be considered in evaluating the system control performance. Since fuzzy controllers are essentially nonlinear and the dynamic behavior of a controlled system is not well known, the closed-loop dynamic behavior is usually very complex. Therefore, the stability of a fuzzy control system must be carefully investigated to guarantee the desired system performance in the presence of different variations and uncertainties. Up to now, various mathematical analysis and design techniques of fuzzy dynamic systems have been devised to ensure the nonlinear fuzzy control system stability. Among the existing methods, Lyapunov stability analysis and passivity theory are two important approaches that have been used extensively in this area.
