3-RPS并联机床的标定建模及振动分析

摘要

The systematic errors,which were produced by the inconsistency of the position reference system with the motion reference system of the parallel machine tool in the calibration,could affect the structural performances of the machine.Both reference systems were unified by improving the calibration modeling approach and the calibration process of the parallel machine tool was numerically simulated.Contrast results found that improved models could completely eliminate the influences of systematic errors on the calibration accuracy of the parallel machine tool during the measurement.By importing the calibrated model into ADAMS for vibration aanalysis and comparing the vibration parameters,the calibrated model was found to obviously superior over the uncalibrated model,which could help further enhance the structural performances of the parallel machine tool.The structure parameter accuracy of the parallel machine tool can be directly improved with the improving machining accuracy and mounting accuracy,but the processing costs will be greatly increased.Kinematic calibration of parallel machine tool by kinematics modeling method only requires ordinary precision machining according to ordinary precision requirements.This calibration modeling method has high practical value.%并联机床在标定时所建立的位置参考系与运动参考系不一致产生系统误差,从而影响机床的结构性能。通过改进标定建模方式,将两个参考系统一,并用数值模拟该并联机床的标定过程,对比结果发现,改进后的模型可以完全消除测量时的系统误差对并联机床标定精度的影响。把标定过的模型导入ADAMS进行振动仿真分析,通过对比可以发现标定过模型的各项振动指标明显优于未标定的模型,从而进一步提高并联机床的结构性能。直接提高机械加工精度及安装精度能够提高并联机床的结构参数的精度,但其代价将是极大地增加加工成本,采用运动学标定并联机床的运动学建模的方法则只需要按普通精度要求进行机械加工,这种标定建模方式具有很高的实用价值。