精密工程中的“免形状测量模式”

"Form-Free Measurement Mode" in Precision Engineering

为测量未知名义几何模型和参数的零件,提出了"免形状测量模式".该测量模式通过高精度获取被测轮廓的"数据微粒",建立典型几何要素及其内在不变量的理论模型,作为识别被测要素几何形状的准则;根据识别准则识别被测轮廓的名义几何形状;利用数据处理与误差分析软件,确定几何参数进而完成误差评定.论述了两个关键问题,即几何信息获取和几何形状识别.分析了几何信息获取的关键技术,阐述了对测量仪器的要求,介绍了结合内插和外插技术的自适应采样策略;提出了用于几何形状快速识别的6个算子;研制了测量仪器FormFree300,实现了"免形状测量".

To measure the components without nominal geometrical form and parameter, the ＂form-free measurement mode＂ was presented in this paper. To accomplish this measurement mode, the ＂data par- ticulates＂ of measurand were obtained with high accuracy, the theoretical models of typical geometries and their invariable moments were set up as the principle for form recognition, the nominal form of mea- surand was recognized according to the principle, and geometrical parameters were calculated and meas- urement uncertainty was assessed by data process software. Two correlative critical aspects, extraction of geometrical information and recognition of form, were discussed. The extraction techniques of geometrical information were analyzed, the requirements on measuring machine were clarified, and an adaptive sam- piing method combining interpolation with extrapolation techniques was introduced. Six fast arithmetic op- erators for geometrical form recognition were presented. A measuring machine, FormFree300, was fabri- cated and the function of ＂form-free measurement mode＂ was realized.