电涡流传感器的脉冲激励与双参数检测  

Pulsed Excitation and Dual-parameter Measurement Method for Eddy Current Sensor

作　　者：董永贵[1] 孟凡[1] 张琦[1] 

机构地区：[1]清华大学精密仪器与机械学系,精密测试技术及仪器国家重点实验室,北京100084

出　　处：《仪表技术与传感器》2009年第B11期221-224,共4页Instrument Technique and Sensor

基　　金：国家自然科学基金资助项目(60672012)

摘　　要：采用矩形脉冲作为激励信号,对电涡流传感器在位移检测过程中谐振频率及谐振阻尼的变化情况进行了研究分析。建立了以现场可编程门阵列(FPGA)为核心芯片的检测系统,用于产生所需要的矩形脉冲激励信号以及对传感器响应信号的欠采样。利用8 mm直径的电涡流线圈,对0～10 mm范围内碳钢目标靶的位移响应特性进行了测量,借助短时傅里叶变换分析了响应信号中频率成分的分布情况,同时获得了谐振频率及谐振阻尼的测量值。验证了通过脉冲激励同时获取电涡流传感器双参数检测的可行性。为研制基于电涡流效应的位移传感器及无损探伤传感器提供了一种新思路。A square-wave pulse was utilized as the excitation signal for an eddy current sensor to investigate the variation of both the resonant frequency and resonant damping during displacement measurement. Using a Field Programmable Gate Array （FP GA） element as the core chip, an interrogation system was established to generate the required square-wave pulse excitation signal and undersample the response signal of the sensor. A carbon steel plate is adopted as the measurement target, the displacement-responsibility characteristics of an 8 mm diameter eddy current coil was measured in the range from 0 mm to 10 mm. The frequency distribution of the response signal was analyzed by short time Fourier transformation. The measurement values of both the resonant frequency and resonant damping are obtained simultaneously, from which the feasibility of obtaining tow parameters of an eddy current sensor by pulsed signal excitation method is verified. This design can be further applied for developing new kind of displacement and nondestructive flaw detection sensors based on eddy current effects.

关 键 词：电涡流传感器 脉冲激励 谐振频率 谐振阻尼 可编程门阵列 

分 类 号：TP212.9[自动化与计算机技术—检测技术与自动化装置]