双柔性空间机械臂动力学建模与控制

Dynamic Modeling and Control of Space Manipulator with Flexible Joints and Links

大多数研究者在空间机械臂动力学建模时,只考虑了关节柔性或者臂杆柔性,并且通常采用假设模态法对臂杆的变形进行描述,但该方法仅适用于小变形情况。基于这种情况,采用自然坐标法对柔性关节进行建模和绝对节点坐标法对柔性臂杆进行建模,得到了既包含关节柔性又包含臂杆柔性的空间机械臂动力学方程,并能精确地描述臂杆的小变形以及大变形。利用5次多项式对关节轨迹进行规划,通过逆动力学得到关节的前馈驱动力矩;采用PID控制策略,作为反馈输入。在二连杆柔性关节柔性杆机械臂上进行数值仿真。仿真结果表明:该控制策略在实现关节轨迹跟踪控制的同时,也能有效减弱机械臂的振动。

Only joint flexibility or link flexibility is considered in the dynamic modeling of the space ma- nipulator by most researchers, and the assumed mode method, only suitable for small deformation, is u- sually utilized to describe the flexible deformation of link. Both nature coordinate formulation （NCF） to model the flexible joint and absolute nodal coordinate formulation （ANCF） to model the flexible link are used to obtain the dynamic equations of the space manipulator, which include both joint flexibility and link flexibility and are able to precise developed by quintic polynomial func ly tio ics as feedforward. PID control scheme describe both small and large deformations. The joint trajectory is n and then the actuator torque is obtained by the inverse dynamused as feedback input. The two-link flexible manipulator is used to evaluate this method. Results show that the proposed control scheme is effective in both the tracking of joint trajectory and suppressing of vibration.