Adaptive Fuzzy Fault-Tolerant Control of High-Order Nonlinear Time-Varying Delay Systems with Dead-Zone Inputs: A Fully Actuated System Approach

This paper investigates adaptive fault-tolerant (FT) tracking control for high-order nonlinear time-varying delay strict-feedback system (SFS) with non-affine nonlinear faults and non-symmetric dead-zone inputs. A novel adaptive fault-tolerant control strategy is developed by combining the theory of high-order fully actuated (HOFA) systems, dynamic surface control techniques, the finite covering lemma, and generalized approximation of fuzzy logic systems (FLSs). Notably, there is no need to reduce the order of high-order systems. Utilizing the finite covering lemma and fuzzy logic systems to address the issue of unknown time-varying delays, this control scheme circumvents the use of Lyapunov-Krasovskii functions, thus removing the condition that the time derivative of the time-varying delay function must be less than one. Through Lyapunov function theory, it is rigorously proved that the designed controller ensures both the stability of the closed-loop system and the convergence of the tracking error to a small neighborhood of the origin. Simulation results are presented to demonstrate the feasibility and effectiveness of the proposed control scheme.