Adaptive Saturated Fault-Tolerant Control for Spacecraft Rendezvous with Redundancy Thrusters

This article investigates the spacecraft rendezvous control problem in the presence of parametric uncertainties and external disturbances. Redundancy thrusters subject to undesirable saturations and faults are also considered. Benefiting from the asymmetry and smoothness of the Gauss error function, we introduce a new saturation function to model each thruster saturation with asymmetric magnitude constraints. By augmenting the six-degree-of-freedom (6DOF) spacecraft relative dynamics with auxiliary dynamic systems, a novel adaptive saturated fault-tolerant control strategy is proposed. In particular, an optimization method is designed to solve the control allocation (CA) problem considering the thruster faults and saturations. In terms of Lyapunov theorem, it is demonstrated that the closed-loop augmented system driven by the proposed control scheme is asymptotically stable. Finally, the simulation results validate the effectiveness of the proposed control scheme.