Adaptive Tracking Control for A Class of Nonlinear Systems With a Fuzzy Dead-Zone Input

This paper focuses on a problem of adaptive control for a class of nonlinear strict-feedback systems with a fuzzy dead zone and immeasurable states. By using the adaptive back-stepping technique, an adaptive fuzzy output-feedback controller is constructed. The proposed control method requires only one adaptive law for an nth-order system. Compared with the conventional deterministic dead-zone models in previous articles, the main advantage of this paper is that the proposed dead-zone-model is uncertain and fuzzy. By defuzzifying for fuzzy dead zone (Gamma) over tilde (u) and employing an integrated design, an integrated fuzzy controller is constructed. It is proved that, even though the dead-zone input (Gamma) over tilde G(u) is fuzzy, the integrated fuzzy controller can make the closed-loop system semiglobally uniformly ultimately bounded and the tracking error converge to a small neighborhood of the origin. Finally, simulation results are provided to show the effectiveness of the proposed approach.