Adaptive fuzzy fault‐tolerant control for a class of unknown non‐linear dynamical systems

Abstract

This study investigates the adaptive fuzzy fault-tolerant control (FTC) problem for a class of non-linear multi-input multi-output systems with interconnections among subsystems and external unknown disturbance. The introduced multiple coupling terms have unknown non-linear forms relying on the system outputs and the corresponding subsystems, which cause that the system is no longer pure-feedback. Moreover, the considered actuator failures have a lock-in-place type and a type of loss of effectiveness. To solve the problem of actuator faults, compensative adaptive laws are constructed by taking advantages of the global fuzzy approximation property and a novel backstepping design procedure. According to the Lyapunov stability theorem, it is shown that all the signals in the closed-loop system are bounded and the outputs can converge to a giving compact set. In addition, simulation examples are presented to validate the effectiveness of the proposed adaptive fuzzy FTC protocol. Compared with previous researches on non-linear systems with unknown coupling terms, the proposed adaptive fuzzy FTC approach is more general, which may provide promising prospects of implementing in practical industrial systems.