Adaptive fuzzy tracking control for a class of uncertain nonlinear systems

An adaptive fuzzy control algorithm is designed for a class of uncertain nonlinear nonaffine systems. Fuzzy logic systems are used to approximate unknown nonlinear functions. In contrast to the previous results of nonlinear nonaffine systems, a main advantage is that it does not require a priori knowledge about the sign of the control gain coefficient. It can be proven that the closed-loop system is stable in the sense that all the signals are bounded and the system output track the reference signal to a small neighborhood of the origin by appropriately choosing design parameters.