Fuzzy adaptive asymptotic tracking of uncertain nonlinear systems with full states constraints

Abstract

ABSTRACT In this paper, the fuzzy adaptive tracking control problem is studied for a class of nonlinear strict feedback systems with time-varying full state constraints. For the full state constraints problem, the nonlinear transformation function is used to transform the constraint problem into a non-constraint problem. A new adaptive control framework is proposed for asymptotic tracking of nonlinear systems with unknown virtual control coefficients (UVCC). Under the proposed control scheme, the effects of UVCC and unknown nonlinear functions are compensated by the introduction of some well-defined smoothing functions and boundary estimation methods. In addition, a new Lyapunov function is constructed, which successfully achieves the tracking error of the closed-loop system converge to zero and all the signals in the closed-loop systems are bounded. In the meanwhile, all states are always keep in their asymmetric time-varying constraints. Finally, a numerical example is presented to show the effectiveness of the proposed control scheme.