考虑测量不确定和输入饱和的充液航天器自适应鲁棒控制

本文研究了三轴稳定充液航天器控制系统中同时存在测量不确定,外部未知干扰,参数不确定和控制输入饱和的鲁棒自适应姿态机动控制问题.建模过程中,将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充液航天器的耦合动力学方程.提出了一种将反步控制方法结合非线性干扰观测器和指令滤波器的鲁棒饱和输出反馈复合控制策略,该控制策略不仅能继承反步控制方法的优点,而且通过引入非线性干扰观测器实现对未知外部干扰,参数不确定以及测量不确定的补偿,还能利用指令滤波器处理控制力矩输入饱和的不利影响.基于Lyapunov稳定性分析方法证明了系统状态变量的渐进稳定性.仿真结果验证了提出控制方法的有效性和鲁棒性.

Adaptive robust control of liquid-filled spacecraft with uncertain measurement and input saturation

In this paper, the three-axis stabilized liquid-filled spacecraft control system with uncertain measurement, unknown external disturbances, uncertain parameters and control input saturation is studied. In the modeling process, the sloshing liquid fuel is equivalent to the viscous spherical pendulum model, and the coupling dynamics equation of the liquid-filled spacecraft is derived by the law of conservation of momentum. A robust saturated output feedback hybrid control strategy combining a backstepping control method with a nonlinear disturbance observer and a command filter is proposed. This control strategy not only inherits the advantages of the backstepping control method, but also introduces a nonlinear disturbance observer to achieve the compensation for unknown external disturbances, uncertain parameters and measurement, and can also use the command filter to deal with the adverse effects of control input saturation. The asymptotic stability of the system state variables is proved based on the Lyapunov stability analysis method. The simulation results verify the effectiveness of the proposed control method.