基于敏感度分析的机床关键几何误差元素辨识与评定

为了正确识别和判定机床关键几何误差元素对机床精度设计的影响,以PCV-620立式加工中心为研究对象,采用多体系统理论建立机床空间误差模型,从而得到机床几何误差元素与机床精度之间的关联函数。对空间误差模型进行灵敏度分析,获得机床各运动方向的局部灵敏度系数,完成机床关键几何误差元素的初步辨识。以局部灵敏度系数为基础,提出一种与局部灵敏度系数和工作空间中任意位置处的几何误差元素值相关的全局灵敏度系数计算方法,将其作为机床关键几何误差元素的辨识和评定标准,分析得到PCV-620立式加工中心的关键几何误差元素包含3项定位误差、3项垂直度误差和5项直线度误差。

Identification and Evaluation of Key Geometric Error Elements of Machine Tools Based on Sensitivity Analysis

In order to correctly identify and determine the influence of key geometric error elements of machine tools on machine tool precision design,taking the PCV-620 vertical machining center as the research object, the multi-body system theory is used to establish the machine tool space error model, so as to obtain the correlation function between the machine tool geometric error element and the machine tool precision. The sensitivity analysis of the spatial error model is carried out to obtain the local sensitivity coefficient of each movement direction of the machine tool, and the preliminary identification of the key geometric error elements of the machine tool is completed. Based on the local sensitivity coefficient, a global sensitivity coefficient calculation method related to the local sensitivity coefficient and the geometric error element value at any position in the workspace is proposed, which is used as the identification and evaluation standard of the key geometric error elements of the machine tool. The key geometric error elements of the PCV-620 vertical machining center include 3 positioning errors, 3 vertical errors and 5 straightness errors.