Observer-Based Adaptive Fuzzy Finite-Time Fault-Tolerant Control for Stochastic Nonlinear Systems with State Constraint

This paper investigates the tracking problem for stochastic nonlinear system with actuator fault and full states constraints. The adaptive laws for nonlinear uncertainties and the estimation of lose effectiveness are combined during the process of controller design. Fuzzy logic systems is utilized to approximate the unknown nonlinear functions. Quartic barrier Lyapunov function is introduced to guarantee the constraints for stochastic system are not violate. Fuzzy observer is designed to handle with the unmeasured states. Lyapunov finite-time stability theorem is used to guarantee the finite-time convergence performance. Then, output feedback-based adaptive fuzzy finite-time fault-tolerant controller is designed. Even the system subject to actuator faults, all the state variables of the nonlinear stochastic system are semi-global ultimately bounded in probability. Compare with the existing result, the control strategy proposed in this paper is more complex and have more potential applications. Finally, two examples are given to verify the validity of the designed control strategy.