Robust parameter design of eddy current meters for electrical conductivity of materials and products of considerable thickness

Abstract

A method for increasing the signal-to-noise ratio SNR of surface eddy current conductivity meters for moving planar metal nonmagnetic (dia-, paramagnetic) and weakly magnetic test objects is proposed. This was achieved because of Taguchi’s robust parameter design of probes with rectangular orthogonal coils, which helped determine their optimal modifications using the design of experiments theory. The given specific examples demonstrate the effectiveness of the method, which, in addition to increasing the SNR, also simultaneously reduces the variance of the output signal. To create a Taguchi design of experiments, a magnetodynamic model of the probe over a moving test object was used, along with the use of orthogonal arrays. The reliability of the found optimal modifications of eddy-current probes is proved by confirming computer numerical calculations. The hierarchy of the degree of influence of the design and operating parameters of probes on their signal characteristics was established by means of variance ANOVA analysis. On this basis, the technical requirements for the accuracy of manufacturing their structures and the conditions for maintaining the stability of the probe‘s operating modes are formulated./////