Vibration suppression and fault-tolerant attitude control for flexible spacecraft with actuator faults and malalignments

Abstract

An efficient and cost-effective finite-time fault-tolerant attitude controller for a class of flexible spacecraft is designed in this paper to cater to flexible appendages' vibrations, along with the simultaneous consideration of erratic inertial uncertainties, environmental disturbances, and actuator-related faults. First, a novel and in-depth modeling of the actuator's performance under output degradation, bias and orientation alignment faults is enacted, which redefines the actuator's performance matrix. Then adaptive estimators are conceived to estimate the lumped uncertainties and actuator-related faults. Based on a modified fast nonsingular terminal sliding mode control (MFNTSM), an adaptive fault-tolerant attitude controller is propounded to realize highly precise attitude tracking and error trajectories' finite-time convergence. The proposed controller's prominent feature is that the unknown uncertainties, actuator-related faults, and flexible vibrations are simultaneously tackled without the aid of intelligent actuators and sensors, which are generally applied for vibration suppression. The spacecraft can accomplish the coveted control objective in bounded time, and the stability of the propound controller is established via Lyapunov techniques. Finally, the simulation outcomes exhibit the profound performance of the propound controller.