基于LabVIEW的电涡流检测二维连续同步扫查系统设计

Design of 2D Continuous Synchronous Scanning System for Eddy Current Detection Based on LabVIEW

基于涡流法利用电机驱动的位移台或扫查架对大尺寸构件进行平面扫查时,由于电机连续运行有加速匀速减速3个阶段,电机运行和数据采集时钟不一致,造成采样点与空间实际位置不匹配,因此提出一种基于LabVIEW的涡流检测二维连续同步扫查系统,提高系统检测效率以及准确性;通过对电机加速运动和减速运动编码器脉冲与采集卡晶振时钟脉冲进行对比分析,并分别将编码器脉冲与晶振时钟脉冲作为数据采集卡采集数据的触发时钟进行实验验证;结果表明,采用晶振时钟脉冲作为采集数据的触发时钟时,成像的裂纹位置与实际裂纹位置有一个明显的偏移;采用编码器脉冲作为采集数据的触发时钟时,成像的裂纹位置与实际裂纹位置基本一致,从而验证了该系统的可靠性以及在工程运用中的可行性。

When using a motor-driven displacement stage or scanning frame to perform continuous two-dimensional planar scanning of large components based on the eddy current method,since the motor runs continuously in three stages of acceleration,constant speed and deceleration,the motor operation and data acquisition clock are inconsistent,causing the mismatch of the sampling points to the actual position in space.Therefore,a two-dimensional continuous synchronous scanning system for eddy current detection based on LabVIEW is proposed to improve the detection efficiency and accuracy of the system.By comparing and analyzing the encoder pulses and crystal clock pulses of the acquisition card during acceleration and deceleration of the motor,and using the encoder pulses and crystal clock pulses as trigger clocks for data acquisition by the data acquisition card.The experimental verification shows that when using the crystal clock pulse as the trigger clock for data acquisition,there is an obvious deviation between the image crack location and the actual crack location.When the encoder pulse is used as the trigger clock for data acquisition,the crack location of imaging is basically consistent with the actual crack location,which verifies the reliability of the system and the feasibility in engineering application.