Design of weak magnetic signal detection system for residual stress detection

Abstract

The residual stress detection based on eddy current method belongs to weak signal detection. Aiming at the problems of sensor output signal with many channels, large amount of data, wide frequency range and low signal-to-noise ratio, a weak magnetic signal detection system is designed and implemented with Zynq-7020 (ARM+ FPGA) as the development board and peripheral hardware circuit. Among them, FPGA controls the peripheral chip to complete the signal source excitation and 8-channel high-speed data acquisition and preprocessing, and then the data is transmitted to ARM through AXI bus. ARM extracts the signal characteristics through digital orthogonal lock-in amplification technology according to the control parameters provided by the upper computer, and feeds back the results to the upper computer. The test results show that the system has high stability and detection accuracy, and meets the overall requirements of the system.