基于反步法的航天器有限时间姿态跟踪容错控制

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

针对存在外部干扰、控制饱和以及执行器故障的航天器姿态跟踪控制问题,提出了基于反步法的有限时间控制方案。通过引入一类新型的具有有限时间收敛特性的积分式滑模面,设计了满足多约束的有限时间容错姿态跟踪控制器,并利用参数自适应方法使控制器设计不依赖于系统惯量信息和外部干扰的界。该容错控制方案的设计无需在线故障信息检测、分离甚至控制器重构,并显式地考虑了执行器输出的饱和幅值要求。稳定性分析表明:在控制饱和甚至执行器故障等多约束的条件下,本文所设计的控制器不仅保证了姿态跟踪的有限时间收敛性,且对于执行器故障具有优越的容错能力;数值仿真分析进一步验证了该控制器的控制性能,以及对外部干扰和系统不确定性的鲁棒性。

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.