带有干扰观测器的凝视航天器姿态变结构控制

Variable structure attitude control of staring mode spacecraft with disturbance observer

摘要:

研究了实现对地凝视观测时的航天器姿态控制问题.首先介绍了对地凝视模式及其成像优点,继而推导出实现对地凝视的期望姿态四元数和期望角速度,在此基础上得到姿态相对动力学和运动学方程;考虑到提高凝视成像精度、延长成像时间的要求,设计了一种变结构控制律,并采用干扰观测器的方法来抑制变结构控制的固有振颤,提高控制效果,并对这种方法和传统控制方法进行了比较.仿真结果表明,在实现对地凝视的姿态控制过程中,设计的控制器响应速度更快,具有更好的鲁棒性,并减弱了变结构控制的振颤问题.

Abstract:

Attitude control problem of staring mode spacecraft in Low Earth Orbits(LEO) is studied in this paper.The staring mode of LEO spacecraft and its merits for observation are initially presented,and then the dynamic equation and kinematic equation are obtained on the basis of deriving the expected attitude quaternion and angular velocities.In order to improve the observation precision and prolong the observation time,a variable structure controller and a disturbance observer are proposed to reduce inherent chattering.Simulation results show that the controller has quick response and good robustness to the inertia parameters uncertainty and the external disturbance,and the chattering of variable structure control is effectively weakened.