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针对挠性航天器执行器卡死与失效故障的姿态稳定控制问题,提出一种改进型滑模容错控制策略。与传统的滑模控制相比,该方法能削弱传统滑模控制中抖振现象对姿态控制精度的影响,且它采用自适应技术在线估计系统中的不确定参数,从而保证控制性能对外部干扰、不确定甚至时变转动惯量具有良好的鲁棒性。该控制器并不需要任何在线或离线的故障信息,能够完全独立于地面站的支持。基于Lyapunov方法从理论上证明了该控制器不但能有效地处理执行器故障,而且保证闭环系统的全局一致最终有界稳定,实现对姿态的高精度控制。最后将所提出的方法应用于某型挠性航天器的姿态稳定任务中,仿真结果验证了该方法的有效性。
Aiming at the problem of attitude stability control of stuck and dead-time of flexible spacecraft actuator, an improved sliding mode fault tolerant control strategy is proposed. Compared with the traditional sliding mode control, this method can weaken the effect of chattering in the traditional sliding mode control on the attitude control precision. It uses the adaptive technique to estimate the uncertain parameters in the system on-line so as to ensure the control performance to the external disturbance , Uncertain or even variable moment of inertia has good robustness. The controller does not require any online or offline fault information and can be completely independent of the ground station’s support. Based on Lyapunov method, it is proved theoretically that this controller not only can effectively deal with the actuator failure, but also ensures the global uniform and ultimately bounded stability of the closed-loop system and realizes the high-precision attitude control. Finally, the proposed method is applied to the attitude stabilization of a flexible spacecraft. The simulation results verify the effectiveness of the proposed method.