Finite-time fuzzy adaptive output feedback control of electro-hydraulic system with actuator faults

Abstract

This article studies the fuzzy finite-time output -feedback control problem on electro-hydraulic systems (EHSs). The EHSs addressed in this study contain unknown states and are subject to actuator faults. The internal leakage and friction are unknown nonlinear functions. By utilizing fuzzy logic systems (FLSs) to approximate the unknown nonlinear dynamics in the EHS and a fuzzy adaptive state estimators are formulated. Subsequently, the unknown states are obtained via the designed state estimators. Further, under the frameworks of finite-time stability a backstepping fuzzy fault-tolerant control (FTC) method is presented. The stability of the controlled electro-hydraulic system is proved by constructing composite Lyapunov functions. The developed fuzzy adaptive control scheme does not assume that the states of controlled electro-hydraulic system must be fully measured directly and has fast convergence and strong robustness against uncertainties. The simulated results and a comparison with the existing control methods are provided to show the validation of the presented control method.