Adaptive fuzzy asymptotic tracking control of uncertain nonaffine nonlinear systems with non-symmetric dead-zone nonlinearities

This paper is concerned with the problem of robust adaptive fuzzy tracking controller design for a class of uncertain nonaffine nonlinear systems with external disturbances and non-symmetric dead-zone nonlinearities. With the help of fuzzy logic systems (FLSs) to approximate the desired nonlinear functions, a novel direct adaptive tracking control scheme is established. First, the implicit function theorem and the mean value theorem are used to deal with the nonaffine term with unknown dead-zone input. Then, based on the estimation information for the unknown upper bound of the compounded disturbance, an adaptive fuzzy tracking controller with the corresponding parameter updating laws is designed to eliminate the effect of the compounded disturbance. Furthermore, it is proved that all the resulting closed-loop system signals are uniformly bounded and the tracking error can asymptotically converge to zero via the Lyapunov stability analysis. Finally, a numerical example is provided to verify the effectiveness of the proposed adaptive fuzzy asymptotic tracking design method.