Research On Sensor Technology Of Acmagnetic Field Induced By Metal

With the rapid development of internet of things industry, identification of item’s information is very important, products using these traditional recognition technologies have application limits, so the new recognition products have a certain market demand. Among them, identification on the metal information represented by metal symbol has received widespread attention, so research on sensor for identification of metal symbol has become heavily critical. In this paper, through the theoretical research on the technology of the magnetic field sensor, make use of new materials of magnetic sensor, design the magnetic field sensor for alternating-current magnetic field measurement of metal inducing, combing with the innovative hardware designing thought, which can accomplish the detection of geometry defect of metal surface.First of all, this paper expounds the classification and engineering background of magnetic field sensor and their designing principle. According to the performance of current sensor, in order to achieve the defection of alternating-current magnetic field induced by metal, introduce the technology of giant magnetic impedance effect and eddy current effect, through the analysis of two kinds of technology, select the amorphous wire, coil and magnetic core as material of sensor, and design experiments, verify the work characteristic of sensor material, design the sensor for detecting alternating-current magnetic field induced by metal. According to the working characteristics of amorphous wire, design amorphous wire probe, extract the magnetic signal. Through the design of conversion and high order low-pass filter, reduce the magnetic field signal to low frequencies, and then design phase locked amplifier circuit, change the alternating-current signal reacting magnetic field into direct-current voltage and through the low noise direct-current amplifier, complete amplification of direct-current voltage which is proportional to the amplitude of alternating-current magnetic field, eventually, realize the detection of alternating-current magnetic field induced by metal surface. According to the working characteristics of the coil and the magnetic core, design the eddy current probe, then according to the change of probe’s parameters, research the technology of phase detection and envelope detection on the probe signal, design the phase detection module and envelope detection module and extract the change of probe effectively, realize the detection of different size defect in metal surface.