Structural Design Of Magnetostrictive Displacement Sensor And Analysis Of Stress Wave Attenuation Property

The research of ultra-precision instruments has been a hot issue for research scholars.Magnetostrictive displacement sensor has the advantages of high measurement precision,easy installation,non-contact and strong anti-interference ability,so it is applied in many fields,such as ultra-precision instrument processing,machine displacement control,oil level measurement and monitoring on-line of longitudinal displacement of rail.Due to the fact that the traditional magnetostrictive displacement sensor has some problems in displacement hysteresis,in addition,the signal-to-noise ratio of the detection signal is low and the measuring range is small,a novel magnetostrictive displacement sensor structure is proposed and the stress wave attenuation in the waveguide wire is studied.Firstly,the axial,circumferential and spiral magnetic fields of the magnetostrictive displacement sensor are simulated.In order to determine the optimal design scheme of each parameter,the experiment of the waveguide material,the magnetic field heat treatment,the detection coil parameter,the pulse current parameter and the permanent magnet parameters in the sensor are carried out.Then,the output voltage model of the magnetostrictive displacement sensor under the influence of hysteresis is established based on the Jiles-Atherton(J-A)model,the Weidmann effect and the piezomagnetic effect.The new sensor structure is proposed to eliminate the hysteresis caused by the hysteresis effect of the magnetostrictive material,to reduce the influence of the remanence and the driving pulse current on the detection signal,and improve the signal-to-noise ratio of the detection signal.Finally,in order to develop a large range of magnetostrictive displacement sensor,two kinds of stress wave propagation attenuation coefficient test method are proposed.The propagation attenuation coefficients of the stress wave in Fe-Ga and Fe-Ni waveguides were tested,and the relationships between the attenuation coefficient and the diameter of the waveguide wire,the stress wave frequency,the stress of the waveguide wire have been determined.In the production of a large-scale magnetostrictive displacement sensor,it can reduce the attenuation of the stress wave,when the diameter of Fe-Ga waveguide wire,stress wave frequency and stress are 0.4mm,32 kHz and 60 Mpa,respectively.The new structure not only eliminates the displacement hysteresis but also is suitable for large-scale magnetostrictive displacement sensor.The question of stress wave attenuation in waveguide wire is studied for the first time.In order to increase the range of the sensor,the optimal parameters of the structure are obtained.