中文摘要：

针对ORU在轨更换任务，首先推导了空间机械臂末端自由、末端与环境接触等情况下的动力学方程，并提出了相应的接触力计算方法；其次，改进了传统的R—C控制方法，采用加权选择矩阵代替原有的选择矩阵，实现了力控制与位置控制之间的平滑切换；最后，开发了基于Matlab／Simulink的闭环控制仿真系统，该系统由多体动力学、接触动力学、轨迹规划、力／位混合控制、3D显示等模块组成。利用该系统开展了ORU转移与安装过程的闭环控制仿真，仿真结果校验了所提方法的有效性。

英文摘要：

Aiming at the ORU on-orbit replacement task, the system dynamics equations are firstly derived under the conditions that the end-effector is free or the end-effector contacts with the enviromnent. The corresponding computational methods of the contact forces are proposed. Secondly, the traditional R-C control method is modified by using weighted selection matrix to replace the original selection matrix, thus achieving a smooth switching between the force control and the position control. Lastly, a closed-loop simulation system based on Matlab/Simulink is developed. It is composed of muhi- body dynamics, contact dynamics, trajectory planning, hybrid force/position control, 3D display modules, et al. By using the system, the closed-loop control simulation of the ORU transfer and installation process is carried out. The simulation results verify the proposed method.