基于涡流检测信号的金属曲面距离测量方法研究

Research on measurement method of metal surface distance based on eddy current test signal

为提高曲面试件的涡流测距精度,提出一种基于涡流信号差值的测距修正方法。该方法通过研究不锈钢平板试件与曲面试件涡流信号的不同,拟合计算出曲面涡流信号和平面涡流信号之间差值与曲面试件曲率的定量关系。利用这一函数关系,对不同曲率试件的测量结果进行补偿,可修正由于试件存在曲面造成的测量误差。通过实验进行可行性验证,对平板试件与不同直径轴件的测距结果进行误差分析。结果表明:相比于直接进行曲面涡流测距的传统手段,该方法将曲面试件测距误差降低60%以上,显著提高曲面测距精度,可应用于金属曲面涡流测距。

In order to improve the accuracy of eddy current measuring of curved specimens, a method based on the subtraction of eddy current signals to correct the distance measurement results is proposed. By studying the difference in eddy current signals between flat and curved specimens, the functional relationship between the eddy current signal difference and the shaft diameter was calculated. This function can be used to compensate the eddy current signal of the curved specimen, and correct the error caused by the existence of the curved surface. The feasibility verification was carried out through experiments, and the error analysis was performed on the distance measurement results of the flat specimen and the shaft with different diameters. The results show that compared with the traditional method of directly measuring the surface eddy current distance, the method reduces the distance measurement error of the curved specimen by more than 60%. This method significantly improves the accuracy of surface ranging, and can be applied to metal surface eddy current measuring.