Finite-Time Prescribed Performance-Based Adaptive Fuzzy Tracking Control for Switched Nonlinear Systems with Output Dead Zone

Abstract

In this article, an adaptive prescribed performance tracking control scheme is proposed for switched nonlinear systems with output dead zone and unmeasured state variables using an adaptive fuzzy approach. Fuzzy logic systems are utilized to learn the unknown nonlinear functions. The output nonlinearity is resolved via introducing Nussbaum function. The novelty of this article is that a shift function is utilized to break the strict restriction that the initial value of the tracking error must be within the initial value of the finite-time performance function. In addition, a switched observer is adopted to reduce the conservativeness caused by the use of a common observer. Then, by combining the average dwell time scheme and the backstepping technology, a novel observer-based fuzzy adaptive controller is developed, which can assure that all the closed-loop signals of the switched systems are bounded under a type of slowly switching signals and the tracking error converges to a pre-specified range in finite time even if the initial value of the tracking error is greater than the performance function. Finally, the simulation results are shown to verify the feasibility of the presented control scheme.