计量比对中用内插法确定参考值的应用分析

Application analysis of determining reference values by interpolation in metrological comparison

计量比对是技术监督的重要手段,比对中应选择稳定性良好的传递标准,计算参考值时应计算出传递标准的不稳定性,传递标准的不稳定性引入的不确定度分量要有合理的评定计算方法。以扭矩扳子比对为例,比对测量点为300 N•m,利用传统的算术平均法和加权平均法对参考值、参考值的不确定度和En值进行了详细的计算,计算中给出了正强相关时,参考值的不确定度计算方法,创新性地使用分段内插法对参考值、参考值的不确定度和En值进行了详细的计算。对算术平均法、加权平均法和内插法的计算结果进行比对得出结论,在对En值进行评价时,考虑传递标准的不稳定性造成的影响,分析传递标准的重复性、稳定性等具体特性。当发现传递标准在比对期间有线性漂移的情况时,应采用内插法对实验数据进行修正。

Metrological comparison is an important means of technical supervision.The transfer standard with good stability should be selected in the comparison.The instability of the transfer criteria should be calculated when calculating the reference values.A reasonable evaluation and calculation method should be provided for the uncertainty component introduced by the instability of the transfer standard.The comparison of torque wrench is taken as an example.The measuring point for comparison is 300 N•m.The reference value,the uncertainty of reference value and the En value are calculated in detail by the traditional arithmetic mean method and weighted average method,as well as the method of calculating the uncertainty of reference value in the case of positive strong correlation is given in the calculation.The reference value,the uncertainty of reference value and the En value are calculated in detail by using piecewise interpolation innovatively.By comparing the calculation results of arithmetic mean method,weighted average method and interpolation method,it is concluded that the influence of the instability of transfer standard should be considered when evaluating En value,and the specific characteristics,for example,the repeatability and stability of transfer standard,should be analyzed.When it is found when the linear drift occurs to the transfer standard during comparison,interpolation method should be used to correct the experimental data.