基于快速非奇异终端滑模的姿态控制技术

Attitude Control Technology Based on Non-Singular Fast Terminal Sliding Mode

针对存在执行器故障与外部干扰的刚体飞行器姿态控制系统,提出一种基于快速非奇异终端滑模(NSFTSM)的姿态容错控制方法。控制方法不仅保证姿态机动过程的快速性,而且避免了传统的终端滑模面所带来的奇异性问题。采用二阶鲁棒精确微分器估计执行器故障与外部干扰,采用快速非奇异终端滑模技术设计姿态容错控制律,根据Lyapunov稳定性理论证明了方法的稳定性。稳定性分析表明,通过引入新型快速非奇异终端滑模,控制器使得闭环系统能够快速收敛到滑模面的微小邻域内,进而收敛到系统平衡点的微小邻域内,并且系统对外部干扰具有较强的鲁棒性。数值仿真结果验证了方法在姿态跟踪控制中的有效性。

A novel attitude tolerant control law based on non- singular fast terminal sliding mode （NS- FTSM） is investigated for a rigid spacecraft,in which the actuator fault and external disturbances are ex- plicitly considered simultaneously. Specifically, in this proposed control scheme, the fast convergence of spacecraft attitude tracking is achieved, and also singularity can be avoided in comparison with traditional terminal sliding mode. Firstly, the second- order differentiator proposed for the estimate of the actuator fault and external disturbances,Then,in the design of attitude tolerant control, a non- singular fast termi- nal sliding mode has been integrated, Last, finite time stability has been analyzed by the Lyapunov theo- rem. The stability analysis shows that the controller ensures the closed- loop system can converge to the small neighborhood of the sliding surface fastly and then to the small neighborhood of the equilibrium point, and has better robustness to external disturbances. In order to show the fault- tolerant effectiveness of the proposed control law in attitude tracking, simulation results have been presented.