基于GMR传感器的金属表面缺陷检测系统设计

随着经济的发展汽车越来越普及,有些关键部位的零件如制动盘和转向节,在制造和使用的过程中容易产生一些细小的裂纹,这就需要在不给被测物体造成负面影响的前提下对关键零器件进行检测;针对传统的涡流传感器进行有限元仿真,分析了激励线圈和被测金属耦合时的传感特性;设计了一种基于GMR芯片检测微裂纹的探针,并开发了相应的测试系统;分析了GMR芯片敏感轴对检测结果的影响,采用小波分析的方法对数据进行处理,提高了信号的信噪比;实验结果表明,该探头灵敏度高,通过调整激励频率可以检测金属表面以下5mm处的缺陷。

Metal Surface Defect Detection System Based on GMR Sensor

Abstract: With the development of economy, automobiles are becoming more and more popular. Some key parts such as brake discs and steering knuckles are prone to some small cracks during the manufacturing and use process. It is necessary to prevent negative effects on the measured object. Next, test the key components. The finite element simulation is carried out for the traditional eddy current sensor, and the sensing characteristics when the excitation coil is coupled with the measured metal are analyzed. A probe based on GMR chip to detect microcracks was designed, and a corresponding test system was developed. The influence of the sensitive axis of the GMR chip on the detection result is analyzed, and the wavelet analysis method is used to process the data, which improves the signal-to-noise ratio of the signal. The experimental results show that the probe has high sensitivity and can detect defects 5mm below the metal surface by adjusting the excitation frequency.