Research On Scanning Measurement Technology Based On Sensitive Mechanism Of Coplanar Electrodes

Coplanar electrode testing technology is developed through capacitance tomography technology and is an emerging non-destructive testing technology.With the advantage of single-sided geometry,it is very suitable for occasions where single-sided inspection is required when the measured space is limited.It has very good application prospects in large-scale online detection.Emerging technologies are facing many problems.In this paper considering the need for large-scale rapid detection of the adhesive layer of aerospace insulation materials,the research of scanning measurement technology based on the sensitive mechanism of the coplanar electrode is carried out.Aiming at the problem that the target to be tested needs to be quickly detected on a large scale,a method of parallel scanning measurement of coplanar electrode is proposed.In order to explore how to determine the change of the object field during the movement of a pair of coplanar electrodes,a research on the defect detection technology of a pair of coplanar electrodes is carried out.Based on the establishment of a three-dimensional model of the coplanar capacitance sensor,the influence of the change of the object field on the coplanar capacitance during static measurement is analyzed.In the dynamic detection process,the influence of parameters such as the detection distance and the moving direction on the capacitance data containing the detected defect information is investigated,and then the rule for determining the size of the defect is established.Considering the "soft field" characteristics and "pathological" problems of the coplanar array capacitive imaging system,a detection method of rotation detection method of coplanar array electrode is proposed.The rotation detection method of coplanar array electrode will cause the electric field to change,resulting in a nonlinear change in the sensitive field and capacitance.The sensitive field of each rotation angle is analyzed to establish the extended sensitivity.The rotation method increases the capacitance data,to a certain extent,improves the "pathological" problem of the imaging process.In the reconstructed image,artifacts are reduced,the edge of the defect is clearer and the shape is more consistent with the real defect.In order to reduce the excessive image reconstruction calculation time caused by the increase in the amount of data in the rotating coplanar array electrode detection method,a redundant data processing method based on capacitance change characteristics is proposed.Simulation and experimental studies show that this method can maintain the quality of image reconstruction and obtain the optimal reconstructed image under the condition of least capacitance data,which proves the effectiveness of rotation detection method of coplanar array electrode.