Fixed-Time Fault-Tolerant Control of a High-Order Fully Actuated System Under Actuator Faults and Uncertain Parameters

This study proposes a fixed-time fault-tolerant control strategy for high-order fully actuated (HOFA) systems with actuator faults and parameter uncertainties. An online parameter adaptive law is designed to address system parameter uncertainties, whereas Nussbaum functions and projection operators are used to adaptively handle uncertainties from controller coefficient variations and actuator faults, respectively. A fixed-time fault-tolerant controller is developed to ensure stable operation under bias faults and partial-loss-of-effectiveness faults. By integrating the fault-tolerant controller with the adaptive laws, the HOFA system achieves stable control despite faults and uncertainties. A numerical simulation and a hypersonic vehicle validate the robustness and reliability of the proposed strategy.