在轨服务航天器快速姿态同步的全局鲁棒滑模控制

项目针对在轨服务航天器进行姿态同步时的姿态控制问题，开展快速姿态同步控制以及快速姿态同步过程中的挠性振动抑制研究。在全局滑模控制框架内研究了拟最小时间姿态同步(特征轴姿态同步)的鲁棒控制方法，分别利用时变滑模、积分滑模以及轨迹跟踪滑模技术设计了特征轴姿态同步控制律，改善了特征轴姿态同步的动态性能并提高了姿态同步控制系统的鲁棒性；针对服务航天器对目标航天器的有限时间姿态同步问题，基于终端滑模控制技术设计了有限时间姿态同步控制律，并利用全局滑模思想提出了有限时间姿态同步的全局终端滑模控制律，进一步结合高阶积分滑模控制和最优控制技术研究了固定时间姿态同步的全局滑模控制策略；针对快速姿态同步过程中的姿态机动/振动一体化控制问题，将模型跟踪策略与全局滑模控制技术相结合，并在此框架内利用指令成型和陷波滤波器技术研究了残留振动小且相位延迟低的三轴挠性振动抑制技术。

The main objective of this project is addressing the attitude control problem of on-orbit servicing spacecraft under the circumstance of fast attitude synchronization. Control strategies on fast attitude synchronization and the associated vibration suppression are investigated. Firstly, robust control methods are provided for the near-minimum-time attitude synchronization, i.e., the eigenaxis attitude synchronization, within the framework of global sliding mode control techniques including the time-varying sliding mode, integral sliding mode and the trajectory tracking sliding mode. The resulting attitude synchronization control laws can improve the dynamic performance of the eigenaxis attitude synchronization as well as the system robustness. Secondly, robust control strategies with finite time convergence ability are developed for the finite time attitude synchronization problem between servicing spacecraft and target spacecraft. To begin with, terminal sliding mode technique is utilized to slove the finite time attitude synchronization problem. Then, a global terminal sliding mode based attitude synchronization law is designed by using the global sliding mode philosophy to eliminate the reaching phase in traditional terminal sliding mode. Furthermore, a novel robust finte time control scheme, named robust fixed time control, is proposed by combining the higher order integral sliding mode control approach with the optimal control technique. Lastly, with respect to the maneuver and vibration control problem during the fast attitude synchronization, a composite control strategy with less residual vibration and phase delay is presented, where the obstacle in utilizing the command shapping and notch filter techniques in vibration suppression for triaxial maneuver is removed.The investigation is developed in the framework of modeling following scheme combined with global sliding mode technique.