刚体航天器有限时间输出反馈姿态跟踪控制

为提高航天器系统飞行可靠性,研究角速度信息不可测量的刚体航天器有限时间姿态跟踪控制,将姿态导数信息作为未知状态,设计基于改进自适应超螺旋滑模的状态观测器,避免未知状态导数上界需要已知的约束,将姿态运动方程进行扩维,在有限时间内实现对未知角速度估计.同时考虑环境干扰和模型不确定,设计新的有限时间干扰观测器,结合连续自适应方法实现对系统综合不确定上界的估计.在此基础上,基于终端滑模技术,设计有限时间连续姿态跟踪控制器,较好地减小了控制输入抖振,并采用Lyapunov理论证明了观测器和控制器的有限时间稳定性.最后仿真结果说明了所提方法的有效性.

Finite-time output feedback attitude tracking control for rigid spacecraft

To improve the reliability of spacecraft system, this paper researches the finite-time output feedback attitude tracking control for rigid spacecraft without angular velocity measurement. The attitude derivative is firstly viewed as an unknown state, and a modified adaptive super-twisting sliding mode state observer is designed and the requirement for the upper bound of unknown state is avoided. By extending dimensions of attitude kinematics equation, the precise angular velocity was estimated in finite time. Then, considering environmental disturbances and system uncertainties, and combining a continuous adaptive approach for estimating the upper bound of system uncertainties, a novel finite-time disturbance observer was designed. Based on the terminal sliding mode, a continuous finite-time attitude tracking controllers is also designed. The control chattering is greatly reduced and the finite-time stability for the observer and the controller is proved via the Lyapunov theory. Finally, simulation results illustrate the effectiveness of the proposed method.