摘  要：以坐標測量機測量孔徑為例，闡述測量過程中影響測量結果的不確定度來源，根據(jù)測量模型建立孔徑測量的GUM法不確定度評定模型；利用對坐標測量機的測量系統(tǒng)量值特性指標分析的方法，給出基于量值特性分析法的各標準不確定度分量的評定模型。通過對汽車空調壓縮機后缸體的孔徑測量，比較兩種方法評定的擴展不確定度。實例分析可以看出：對于坐標測量機復雜的非線性測量模型，GUM法在計算靈敏系數(shù)時，運算量較大且獲得的是近似結果，因此其可操作性不強；量值特性分析法通過對測量系統(tǒng)整體的分析，基于大量的實驗數(shù)據(jù)對測量結果進行測量不確定度評定，其流程和操作性更為便捷、有效。
關鍵詞：計量學；不確定度評定；孔徑測量；坐標測量機
文獻標志碼：A       文章編號：1674-5124（2016）01-0026-05
Uncertainty evaluation model for aperture measurement of
coordinate measuring machines
XU Lei， CHEN Xiaohuai， CHENG Yinbao， JIANG Rui， WANG Hanbin， CHENG Zhenying
（School of Instrument Science and Opto-electronics Engineering，Hefei University of Technology，
Hefei 230009，China）
Abstract: The factors which may influence the measurement uncertainty of aperture measurement by coordinate measuring machine （CMM） were analyzed. Two uncertainty models were established based on guide to the expression of uncertainty in measurement （GUM） and measurement system analysis（MSA）. Measurement uncertainty for aperture of workpiece were evaluated by the two methods. Moreover， seen from the evaluation example， the results of uncertainty evaluation obtained from GUM and MSA were compared， the comparison result indicates that GUM method needs large amounts of computation and can only get the approximate results in the calculation of sensitivity coefficient but MSA method analyses the whole measurement system and evaluates uncertainty through a large number of experimental data，which is more convenient and more effective than GUM method.
Keywords: metrology； uncertainty evaluation； aperture measurement； CMM