6UPS并联机构铰链间隙误差的标定与精度分析

研究了常用的机构标定方法及相应的测量工具,使用激光干涉仪完成了测量实验,并使用矢量法误差求解模型对测量结果进行了分析计算,获得了机构静平台铰链的安装位置误差、杆长的误差变化、动平台铰链的位置误差数值,并提出了采用拟合误差椭球面的方法对铰链位置装配误差与铰链间隙误差进行分离的误差分析方法,研究了椭球的求解方法,得到了椭球的长轴、次长轴和短轴参数,进一步比较了所有铰链误差在坐标系中的空间分布情况,研究了机构安装结构和铰链类型与误差分布规律的相互关系,这样优化的误差数据可以取得比较好的补偿效果。

Calibration and Analysis of the Joints Position and Clearance Error on 6UPS Parallel Machine

The common used method of 6UPS parallel grinding machine parameter calibration and corresponding measure tool are studied. A practical calibration experiment that is abided by the vector method is performed by the dual frequency laser interferometer. After the experiment, the coordinate of the static platform of a parallel machine was set up and all of the structural parameters of the machine were obtained. It includes the position of all the joint centers of legs at the static and motion platform, the position of the cutter at the motion platform. Use different group of the orientation and position of the platform, many structural parameters can be obtained. A new error analysis method with elliptic ball was proposed, which can identify the joints position error and clearance error of the machine. The influence space and its center were calculated. These optimizing error data will obtain better compensation effect in motion control.