Robust adaptive fuzzy control for a class of nonlinear systems

A stable adaptive fuzzy output tracking control scheme is developed for multiple-input-multiple-output nonlinear systems with unknown nonlinearities. Using the state observer, this method needs not the assumption that the states are available for measurement. The Lyapunov synthesis approach is used to analyse the fuzzy system to obtain the corresponding parameters adaptive laws based on observer. The key assumption is that the approximation errors satisfy certain bounding conditions. The control law consists of two terms, one is the certainty equivalent control and the other is the bounding control. A bounding parameter adaptive law is used to obtain this bounding control. The proposed fuzzy controller guarantees that system stability and also maintain a good tracking performance. Simulation results show the validity and efficiency of the proposed method.