一种新型并联机床的精度建模与误差分析

Accuracy Modelling and Error Analysis for A New Type Parallel Machine Tool

以一种新型并联机床为对象,提出了一种精度建模方法。将精度建模的问题转化对应的"虚拟机构"的运动分析问题,建立了主进给机构的驱动误差、结构误差及球铰间隙误差与刀尖参考点位姿误差之间的关系式,利用空间矢量链模型推出了并联机床系统位姿误差与主进给机构安装误差、立柱尺寸误差及工作台运动误差间关系的综合表达式,为该新型并联机床的精度补偿提供了理论基础。最后给出了误差分析的数值实例。

A accuracy modelling method for a new type parallel machine tool (PMT) is proposed.This method transforms problem of accuracy modeling into that of kinematic analysis of 'virtual mechanism'. Expressions between drive errors, strucrure parameter errors, spherical joint gap errors as well as the position and orientation errors of a cutter tip reference point are established. The expressions between assembly errors of main feed mechanism, dimention errors of pole, position errors of worktable and position and orientation errors of PMT system are derived by utilizing spatial vector chain model. Above research work will establish the theory basis for error compensation of the new type PMTs. Numerical examples of error analysis are given for illustration.