Backstepping-based finite-time fault-tolerant attitude tracking control for spacecraft

Backstepping-based finite-time control strategies are investigated for spacecraft attitude tracking subject to external disturbances, control saturation and actuator faults. A finite-time fault-tolerant attitude tracking controller is developed by introducing a novel integral-type sliding mode with finite-time convergence, and it is further shown that the controller is independent from a prior knowledge of spacecraft inertia or bound of external disturbances with parameter adaptations. It is important to note that the designed fault-tolerant controller does not require any fault information detection, isolation online even controller reconstruction, and saturation magnitude of actuator output is explicitly taken into account. The stability analysis shows that the finite-time convergence of spacecraft attitude tracking can be ensured by the designed controller with superior fault tolerant capability for actuator faults, even with respect to the multi-constraints such as control saturation and even faults. The control performance of the proposed controller is further evaluated through the numerical simulation analysis, with the robustness to external disturbances and system uncertainties.