3-PRRS型微动并联机构工作空间分析及结构优化

摘要

微动机器人在生物工程和光学工程等领域有着广泛的应用前景.针对国内各种微动机器人结构复杂、不易控制等问题,提出了一种新型6自由度3-PRRS局部解耦柔性微动并联机构.通过建立恰当的坐标系,依据欧拉变换的思想求出机构的位姿逆解,并在逆运动学方程的基础上通过Matlab三维边界搜索法仿真出不同姿态下的工作空间,工作范围可达微米级.以工作空间的大小作为优化目标,运用单元素法对影响工作空间的结构参数进行分析,结果表明与主动转动副相连的支链长度的变化对工作空间的影响更大,与从动支链的变化相比,峰值可以提升33％,且当下平台与上平台外接圆半径之比为1.7时微动机构的工作空间最大.%Micro-actuator has a wide application prospect in bioengineering and optical engineering. Aiming at the problem of complicated structure and uneasy control, a category of partially decoupled 6 degrees of freedom 3-PRRS manipulator is proposed.The equation of inverse kinematics was established based on Euler transformation under proper coordinate system and the workspace under different orientations were simulated by Matlab through three dimensional boundary search method,it shows that the working range of the machine is about few hundred microns.Choosing the size of workspace as the optimum objective,structural parameters influencing the size of workspace were analyzed by means of singleton method. Compared with the length change of passive links,the links'variation of positive revolve joint have greater influence on the workspace, and the peak value is improved about 33% .Micro梐ctuator workspace reaches the maximum value in case that the circumradius proportion of the under platform and the upper platform is1.7.