五轴机床机构运动精度的可靠性分析

摘要

Five-axis CNC machine tool is the top product of numerically controlled machine tool.Kinmatic accuracy is an important index to evaluate the quality of mechanism.Kinematic accuracy analysis of the five-axis machine tool in previous study ignores the randomness of each input error component, so the conclusions are imprecise.Using the homogeneous transformation, inverse kinematics of a five-axis machine tool is calculated.Based on multi-body system theory,error model of the machine tool is presented.Considering the randomness of every input error components, math model of kinematic reliability of the mechanism is deduced.The calculation method of kinematics reliability is put forward.Kinematic reliability analysis provides some theoretical reference for improving the machining accuracy and operation life of machine tool.%五轴联动加工中心是数控机床的高端产品.运动精度是评价机构质量的重要考核指标.以往机床机构运动精度分析中,往往不考虑输入误差的随机性,造成评价结果不准确.应用齐次坐标变换,推导了一种2R3T型五轴机床的运动学方程.基于多体系统理论,建立了机床的误差模型.考虑输入误差的随机性,推导了机构运动精度可靠性计算模型.机床机构运动可靠性分析为提高机床加工精度和使用寿命提供了一定的理论参考意义.