采用观测器的偏置动量小卫星姿态容错控制

Observer-Based Attitude Fault-Tolerant Control of Bias Momentum Microsatellite

针对偏置动量小卫星的自主飞行问题,提出一种基于不确定项观测器的滑模容错控制方法。应用欧拉-拉格朗日系统的干扰观测方法设计不确定项观测器,对动量轮输出力矩变小、磁力矩器线圈电阻漂移等执行器故障以及小卫星外部环境力矩等不确定项进行估计,理论推导证明该观测器的观测误差一致最终有界(UUB)。基于不确定项观测器的估计值,设计补偿控制项,并与滑模控制器的控制力矩合成实现姿态容错控制。从理论上证明该容错控制方法能够使小卫星姿态快速收敛至滑模面。该容错方法无需做小角度假设,对执行器运行状态信息依赖性低。仿真结果表明,本文建议的容错控制方法具备可行性,实现了对小卫星姿控系统中不确定项的观测估计和容错控制。

In order to improve the autonomous operation ability of a bias momentum microsatellite, a sliding mode faulttolerant control method based on an observer of uncertain terms is proposed. Using the disturbance observation method of the EulerLagrange system, an observer of uncertain terms is designed to estimate the actuator faults, such as the reduction of the momentum wheel output torque and the resistance drift of the magnetic torquer’s coil as well as the environmental disturbance torques of the satellite, and the theoretical deduction shows that the observation error of the observer is uniformly ultimately bounded (UUB). The estimated values of the observer are used for the feedback compensation of the sliding mode faulttolerant controller. The stability analysis shows that the proposed method can quickly converge the satellite attitude to the sliding surface. It is noted that the control method proposed in this paper does not need to make the smallangle assumption and the faulttolerant control process is not dependent on the working state information of the actuators. The attitude control performance is evaluated by the numerical simulations.