Magnetostrictive Linear Displacement Sensor And The Signal Enhancement Methods

Magnetostrictive displacement sensor is a displacement measuring instruments which has high precision, large range, anti-interference ability of advantages has been widely used in liquid level measurement, industrial control and other areas.Range is an important performance index of the displacement sensor, but the signal strength of torsional wave attenuated continuously with the increases of propagation distance, which limits the measuring range of magnetostrictive displacement sensor.The study of method to enhance the signal intensity of torsional wave has important significance for the range expansion.This paper first describes the principles of traditional magnetostrictive displacement sensor and analyzes the characteristics of conventional sensor structure and summarizes several methods commonly used to enhance the signal and its shortcomings.Study the effects of pulse width on output signal through experiments, and obtain the conclusions that output signal is the superposition of signal that excitated by the rising and falling edges of the pulse.On this basis, the experimental study on the enhancement of the reflection echo signal And then enhance the of signal by the structure of bipolar position magnet, study the effects of pulse width on output signal through experiments in two cases that with echoes and no echoes.Finally, further enhances the original signal by the method of wave array.Study the signal changes under different arrays order through experimental, experimental verify the signal enhancement effect of wave array. For the signal characteristic of wave array,propose the select of time point for measurement.According the function of magnetostrictive displacement sensor,design the corresponding hardware circuit and system, including the power amplifier circuit and signal processing circuit.Using the pulse counting method as the time measurement program, and improve the timing resolution through the multiple phase-shifted clock counting methods. Finally, FPGA + STM32 hardware architecture is used to achieve a measurement system, and designed the corresponding software.