用田口方法推断校准仪器的测量不确定度

在测量过程中存在许多可能引起测量结果的不确定度分量,这些不确定度分量的综合效应影响,使得测量结果的可能值按某种概率分布。在对仪器进行校准时,给出测量结果的同时还应给出其测量不确定度。传统的计算方法是对典型点进行多次测量,求出算术平均值和实验室标准偏差,从而求出测量不确定度,此法很难给出测量范围内任一点的测量不确定度。田口方法利用测量误差损失函数及测量特性的信噪比等参数来表征测量质量的优劣,可以很好地解决测量过程中任一点的测量不确定度求解难题。本文简要介绍了田口方法的原理及其应用,着重叙述了在已知部分测量数据的基础上如何利用田口方法推断出校准参数的估计值以及相应的测量不确定度,并通过实例验证了其正确性和可行性。此方法的计算过程适合计算机编程,使该方法的推广应用成为可能。

Uncertainty of Measurement for Calibrated Instrument Deduced with Taguchi Method

The parameters of a calibrated instrument are random variables obeying some kinds of distributions because of many uncertain factors existing. These uncertain factors make the measurement value in a range that relate to uncertainty. The measurement result and measurement uncertainty are ought to have provided when instruments are calibrated. Some of typical measuring points of parameters are selected to calibrate and arithmetical means and laboratory standard errors are asked to calculate in classical method, then the uncertainty is given according to the uncertainty synthesizing principle. It is impossible to provide calibration value and the uncertainty of anyone point in measurement range for a kind of calibration parameter with classical method. The Taguchi method shows the quality of measurement with measurement error expense function and the S/N ratio of measurement speciality. This method can solve the problem to calculate anyone uncertainty. The concept of measurement uncertainty and the principle of the Taguchi method are introduced in this paper, and it is described in detail how to use Taguchi method to deduce calibration formula and related measurement uncertainty according to some measurement data. A experiment given here has proved that this method is viable. It is possible to use The Taguchi method widely in engineering because the calculating process can carry into execution with computer.