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针对刚体航天器大角度姿态机动问题,研究了具有全局鲁棒性的特征轴机动控制策略。设计了一种指数时变的滑模面和相应的姿态机动滑模控制律,控制律使系统相轨迹从初始时刻起就始终处于滑动阶段,消除了传统时不变滑模控制的到达阶段,对外界扰动及参数不确定性具有全局鲁棒性,并实现了特征轴机动;通过Lyapunov定理证明了提出控制律的稳定性及全局滑模运动的存在性;利用全局滑模运动的特点得到系统任意时刻状态的解析表达式,表明姿态误差响应无超调,系统具有良好的动态性能。进一步考虑了控制力矩饱和问题,利用力矩指令调节器在避免控制力矩饱和的同时保证特征轴机动的特点。最后通过数值仿真验证了控制律的优点。
Aimed at maneuvering large-angle attitude maneuver of rigid spacecraft, a globally robust maneuvering strategy of the characteristic axis is studied. An exponential time-varying sliding mode surface and the corresponding attitude maneuvering sliding mode control law are designed. The control law keeps the system phase trajectory at the sliding stage from the initial moment and eliminates the arrival stage of the traditional constant sliding mode control. It is globally robust to external perturbations and parametric uncertainties, and implements the characteristic of axial maneuvers. The stability of proposed control law and the existence of global sliding mode motion are proved by Lyapunov theorem. The global sliding mode motion is used to obtain the system The analytical expression of the state at any moment indicates that the attitude error response has no overshoot and the system has good dynamic performance. Further consider the control of torque saturation problem, the use of torque command adjuster in the control of torque saturation to avoid the same time to ensure the characteristics of motor characteristics. Finally, the numerical simulation validates the advantages of the control law.