航天器自适应快速非奇异终端滑模容错控制

针对存在外部干扰、转动惯量矩阵不确定、控制器饱和以及执行器故障的航天器姿态跟踪控制问题，提出了基于自适应快速非奇异终端滑模的有限时间收敛控制方案。通过引入能够避免奇异点的具有有限时间收敛特性的快速非奇异终端滑模面，设计了满足多约束的有限时间姿态跟踪容错控制器，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上界。此外，所设计的控制器显式考虑了执行器输出力矩的饱和幅值特性，使航天器在饱和幅值的限制下完成姿态跟踪控制任务，并且无须进行在线故障估计。Lyapunov稳定性分析表明：在外部干扰、转动惯量矩阵不确定、控制器饱和以及执行器故障等约束条件下，所设计的控制器能够保证闭环系统的快速收敛性，而且对控制器饱和与执行器故障具有良好的容错性能。数值仿真校验了该控制器在姿态跟踪控制中的优良性能。

Spacecraft fault-tolerant control using adaptive non-singular fast terminal sliding mode

Finite-time convergence control strategies based on adaptive non-singular fast terminal sliding mode are proposed for spacecraft attitude tracking subject to external disturbances, inertia uncertainties, control saturation and actuator faults. A finite-time fault-tolerant attitude tracking controller meeting the multi-constraints is developed by introducing a non-singular fast terminal sliding mode with finite-time convergence and singularities avoidance attributes. It is further shown that the controller is independent from inertia uncertainties and bound of external disturbances with parameter adaptations. In addition, the controller designed in this paper explicitly considers the actuator output torque saturation amplitude requirements, which makes the spacecraft complete the given operations within the saturation magnitude and without the need for on-line fault estimate. The Lyapunov stability analysis shows that the designed controller can guarantee the fast convergence of the closed-loop system and has a good fault tolerant performance on control saturation and actuator faults under the multi-constraints on external disturbances, inertia uncertainties, control saturation and actuator faults. Numerical simulation has verified the good performance of the controller in the attitude tracking control.