Observer-based adaptive fuzzy tracking control of MIMO switched nonlinear systems preceded by unknown backlash-like hysteresis

This paper considers the problem of adaptive fuzzy output feedback tracking control for a class of multi-input and multi-output (MIMO) switched nonlinear systems with hysteresis nonlinearities, where the hysteresis nonlinearities are described by a set of differential equations with unknown parameters. Fuzzy logic systems, as specialized function approximators, are employed to approximate the unknown nonlinear functions of the system under study. A MIMO switched fuzzy observer is constructed to tackle the problem of unmeasured states, and the dynamic surface control technique is introduced to avoid the appearance of repeated differentiations existing in most traditional backstepping designs. Based on the multiple Lyapunov function approach, an adaptive fuzzy output feedback controller is developed. The proposed control scheme can guarantee that all the signals in the resulting closed-loop system are semi-globally uniformly ultimately bounded (SGUUB) under a class of switching signals with average dwell time, and the outputs to track given reference signals exactly. Simulation results demonstrate the validity of the control scheme. (C) 2019 Elsevier Inc. All rights reserved.