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讨论了空间机器人双臂捕获航天器后姿态管理和辅助对接操作的协调控制问题.首先,利用冲量定理、闭环约束几何及运动学条件获得了捕获操作后闭链混合体系统的动力学方程,并分析了混合体系统受到的冲击效应.其次,针对捕获操作后系统姿态受扰运动镇定及辅助对接操作需求,对闭链混合体系统提出了基于极限学习机(ELM)的自适应神经网络控制方案,极限学习机具有学习速度快、仅需调节网络输出权值等优点,可用于逼近系统的未知动力学模型.该方案不要求系统动力学方程关于惯性参数呈线性函数关系,并且不需要精确的系统动力学模型.通过李亚普诺夫方法设计了ELM网络的权值自适应律及鲁棒项,以保证系统的载体姿态受扰运动镇定与对接操作过程的位置及角度的精确控制,并证明了系统的稳定性.为保证各臂协同操作,运用加权最小范数法分配力矩.最后,通过系统数值仿真模拟了碰撞冲击效应及闭链系统的运动过程.所提控制方案可以有效完成载荷、载体运动控制及辅助对接操作.
The coordination control of post-spacecraft attitude management and auxiliary docking operations is discussed.Firstly, the dynamic equations of the closed-chain hybrid system after the capture operation are obtained by impulse theorem, closed-loop constraint geometry and kinematics The impact of the hybrid system is analyzed.Secondly, an adaptive neural network control scheme based on limit learning machine (ELM) is proposed for the closed-chain hybrid system in view of the stabilization of the system disturbance and the demand of the auxiliary docking operation after the capture operation. The limit learning machine has the advantages of fast learning speed and only adjusting the output weight of the network and can be used to approximate the unknown dynamical model of the system.The system does not require that the system dynamics equation has a linear function relationship with respect to the inertial parameter and does not require accurate System dynamics model.The adaptive law of weights and robustness of the ELM network are designed by Lyapunov method to ensure the precise control of the position and angle of the disturbed movement of the system and the docking operation process, System stability.In order to ensure the coordinated operation of all arms, the weighted least-norm method is used to distribute the torque.Finally, Through the numerical simulation of the system, the collision impact effect and the motion of the closed-chain system are simulated, and the proposed control scheme can effectively accomplish the load, carrier motion control and auxiliary docking operation.