Quantitative Detection Method for Defects of Curved Metal Materials Based on Four-Axis Platform and Flexible Array Electromagnetic Sensor.

A quantitative detection method for curved metal defects based on flexible array electromagnetic sensor and four-axis platform is proposed in this paper. Under the control of a four-axis platform, the flexible array eddy current sensor can fully fit the complex curved surface, where the R-axis (rotation axis) controls the surface attitude, and the X/Y/Z axis controls the sensor movement position. Firstly, according to the rotation matrix, we derive the correlation between the rotation angle of R-axis and the inclination angle of the measured segment. Then, the detection path calculation and planning method of the complex surface is established. So, 3D defect detection images can be reconstructed according to the location information and sensor signals. Finally, we realize the quantitative detection of defects on complex curved metal based on the maximum interclass variance method. Experimental results show that this method can reconstruct the three-dimensional detection image of complex curved metal surfaces, and the quantitative detection of complex surface defects can be realized based on the image, and the quantitative error is less than 6%. [ABSTRACT FROM AUTHOR]