8自由度铺丝机械手的自运动流形分析

Self-motion manifold analysis on 8-DOF fiber placement manipulator

针对梯度投影算法所得冗余机械手关节逆解不一定包括最优解的缺陷,提出一种分析8自由度冗余铺丝机械手关节逆解的流形方法.利用流形法所得逆解包含了冗余机械手的全部关节逆解,有利于实现自运动控制的全面优化.根据逆解流形的空间多维特性,在8自由度铺丝机械手的关节空间内分别定义其位置关节子流形和姿态关节子流形,并分别得到三维空间中仿真映射曲面.结果表明,由于芯模自由度是在固定空间内的运动,相比于7自由度的铺丝机械手,8自由度铺丝机械手的仿真曲面流形在灵活性及避障碍能力方面均有较大提高.最后以飞机S形进气道为例进行仿真,仿真结果表明,仿真轨迹与期望轨迹高度吻合,证明了所提方法的正确性.

In consideration of the disadvantage that the inverse solutions of redundant manipulator＇sjoints based on the gradient projection method were not always optimal,a newmethod using manifolds to analyze the inverse solutions of an 8-DOF fiber placement manipulator＇s joints was proposed in this study. The self-motion manifolds obtained by this method contain all of the inverse kinematic solution of fiber placement manipulator that helps to optimize the self-motion control roundly. According to the multi-dimensional characteristics of self-motion manifolds,the position joints space sub-manifolds and posture joints space sub-manifolds were respectively defined in working space of the 8-DOF fiber placement manipulator joint space,and the corresponding triaxial simulation curves of the manifolds were obtained respectively. The results showthat the 8-DOF fiber placement manipulator,compared with the 7-DOF fiber placement manipulator,improved a lot in its flexibility and obstacle avoidance abilities because the motion corresponding to the mandrel＇s degree of freedom was in the fixed space. In the last,the method was verified by using the S-shaped inlet simulation. The result shows that the simulation trajectory was highly consistent with the desired trajectory which proved validity of the method proposed by the paper.