Adaptive fuzzy decentralized dynamics surface control for nonlinear large-scale systems based on high-gain observer

This paper discusses the adaptive fuzzy decentralized output-feedback control problem for a class of nonlinear large-scale systems. The systems under study have unknown nonlinearities, mismatched interconnections in control inputs, and unmeasurable state variables. Therefore, fuzzy logic systems are employed to approximate the unknown nonlinear functions in the control design; and an adaptive high-gain observer is established to estimate the unmeasured states. Based on the backstepping design technique and the dynamic surface control (DSC) approach, a novel adaptive fuzzy decentralized output-feedback control scheme is developed. It is proved that the proposed control approach can ensure that all the signals of the closed-loop system are semi-globally uniformly ultimately bounded (SUUB) and the observer error and tracking error can all converge to a small neighborhood of the origin. The effectiveness of the proposed approach is illustrated by simulation examples with comparisons with several existing methods.