针对绳索式末端执行器缠绕及捕获卫星过程中的动力学问题,采用绝对节点坐标方法描述横观各向同性柔性绳索的缠绕运动,及卡尔丹角描述刚体卫星的姿态运动,并引入绳索与目标间的非线性动力学模型,建立包含末端执行器固定环和旋转环、绳索及被捕获卫星抓杆在内的刚柔耦合动力学模型。结合广义d法以及工程上常用的Scaling技术,利用Matlab开发了计算程序,实现动力学方程的高效精确数值求解。计算结果表明:此模型能较好地模拟柔性绳索缠绕及捕获卫星的过程,同时给出捕获过程中卫星姿态的变化及绳索的运动和受力情况,为实际工程中捕获机构的设计和试验提供一定的参考依据。
The problems of dynamics during winding and capturing a satellite by the space manipulator end-effector are studied. The winding movement of transverse isotropic flexible wire ropes is described by absolute nodal coordinate formulation (ANCF) , and Cardan angles are applied to describe the attitude of the rigid satellite. A rigid-flexible coupling dynamic model containing a stationary ring and a rotation ring fixed on the end-effector, three ropes and a shaft of the captured satellite is established. Nonlinear contact force is introduced to reveal the interaction between shaft and wire ropes. The generalized-α method and the scaling technique are employed to develop a numerical calculation program for solving the dynamic equations precisely and efficiently. Simulation results show that the proposed dynamic model can preferably simulate the processes of flexible wire rope winding and satellite capturing. The change of satellite attitude and rope movement during capturing are obtained, which could provide reference basis for design and test of capturing mechanism.