测量不确定的充液航天器自适应鲁棒容错控制

针对三轴稳定充液航天器控制系统中同时存在外部未知干扰，参数不确定，测量不确定和执行器部分失效故障的鲁棒容错姿态机动控制问题进行研究。首先将部分充液贮箱内的晃动液体燃料等效为粘性球摆模型，采用动量矩守恒定律推导出航天器的刚-液耦合动力学方程。然后将变结构控制策略结合范数自适应估计算法设计了自适应鲁棒容错控制器，其中设计的范数自适应控制算法用于有效估计由测量不确定产生的集总扰动的未知上界；自适应估计算法则用于有效估计贮箱内的液体晃动位移变量。提出的控制策略不依赖精确的故障信息，并且在故障信息值不确定的情况下可以实现期望的姿态机动任务。基于Lyapunov稳定性分析方法证明了容错闭环系统状态变量的一致最终有界性。采用数值方法验证了所提控制方法的有效性和鲁棒性。

Adaptive Robust Fault Tolerant Control of Liquid filled Spacecraft with Measurement Uncertainty

For the control of three axis stabilized liquid filled spacecraft, the problems of robust fault tolerant attitude maneuver control with external unknown disturbances, parameters uncertainty, measurements uncertainty and actuator partial failure fault are studied. Firstly, the sloshing liquid fuel in a partially filled tank is equivalent to a viscous spherical pendulum model, and the rigid liquid coupling dynamic equations of the spacecraft are deduced by using the law of conservation of moment of momentum. Then, an adaptive robust fault tolerant controller is designed by combining the variable structure control strategy with the norm wise adaptive estimation algorithm. The designed norm adaptive control algorithm is used to effectively estimate the unknown upper bound of the lumped disturbances caused by the measurement uncertainty, and the adaptive estimation algorithm to estimate the liquid sloshing displacement variables in the tank. The proposed control strategy does not rely on precise fault information and can achieve the desired attitude maneuver task when the fault information value is uncertain. Based on Lyapunov stability analysis method, the uniform final boundedness of state variables of closed loop fault tolerant system is proved. The numerical method is used to verify the effectiveness and robustness of the proposed control method.