基于精度理论的测量不确定度评定与分析

针对测量不确定度表示指南(GUM)所述的测量不确定度评定方法存在的局限性,提出了基于经典精度理论的测量不确定度评定的新方法。分析了当不确定度来源繁杂或测量模型未知等特殊情况时,以测量正确度和测量精密度作为2项主要来源进行测量结果的不确定度评定的优势及理论依据。最后,坐标测量机(CMM)工件端面距离测量的不确定度评定实例验证了该方法的可行性。实验结果表明,CMM测量环境引入的标准不确定度分量相对于正确度和精密度引入的不确定度分量可忽略不计。在测量环境非主要不确定度来源时,测量不确定度评定的初始模型仅需考虑正确度和精密度2项来源就可获得较可靠的测量不确定度。

Measurement uncertainty estimation and analysis based on accuracy theory

In order to assess the limitation of measurement uncertainty estimation of GUM, a new uncertainty estimation method based on classical accuracy theory is presented. In this estimation method, the influence of two main uncertainty components rooted in measurement trueness and measurement precision are discussed. It can be theoretically applied to extreme situation, even when the uncertainty sources are complex or the measurement model is unknown. Besides, the advantages and theoretical bases of this estimation method are analyzed. An experiment of uncertainty estimation for end distance measurement of workpiece by CMM is carried out to verify its feasibility. The experimental result shows that the main sources of measurement uncertainty in CMM test are trueness and precision, and the uncertainty component of measurement environment can be neglected in practice. The environment of this measurement is not the main uncertainty source, and the initial model of the uncertainty is established by combining the two main uncertainty components for trueness and precision. Thus the reliable measurement uncertainty is achieved.