基于少自由度主动支链的2R1T并联机构

2R1T Parallel Mechanism Based on Active Branched Chain with Few Degrees of Freedom

针对空间串联机构的工业机械臂在执行加工操作任务时,普遍存在刚度强度较差、重复精度较低、能耗较高等缺点。基于3条少自由度主动支链,课题组设计了一种具有2R1T自由度的2-RPU/RPS并联机构。计算并验证了2-RPU/RPS并联机构的自由度,获得了解析形式的位置逆解,证实了该机构仅可能发生运动学正解奇异;依据课题组提出的基于边界数值搜索法的工作空间求解流程,证实了动平台具有沿X方向约80°的较大姿态转动范围;通过Solid Works虚拟运动仿真获得了2-RPU/RPS并联机构驱动位移变化曲线。仿真结果表明:机构各驱动位移变化曲线均波动较小且在合理取值范围,说明驱动器运转平稳、能耗较低。本研究可为基于并联机构的复杂曲面工件多轴加工装备研发提供有益的参考。

The industrial manipulator of space tandem mechanism has many shortcomings such as poor stiffness and intensity,low repetition accuracy and high energy consumption when performing processing operations.A2-RPU/RPS parallel mechanism with 2R1T degrees of freedom was designed based on three active branched chains with less degrees of freedom.The degree of freedom of the 2-RPU/RPS parallel mechanism was calculated and verified,and the inverse solution of the analytical form was obtained,which confirmed that only the forward solution singularity of the mechanism could occur.According to the proposed workspace solution process based on the boundary numerical search method it is proved that the moving platform has a large attitude rotation range of about 80°along the X direction.The 2-RPU/RPS parallel mechanism driving displacement change curve was obtained through SolidWorks virtual motion simulation.The simulation results show that the displacement change curve of each driving displacement of the mechanism fluctuates less and is within the reasonable value range,indicating that the driver runs smoothly and consumes less energy.This study provides a useful reference for the research and development of multi-axis machining equipment for complex curved workpiece based on parallel mechanism.