The Design Of Magnetostrictive Linear Displacement Sensor

Line displacement plays an extremely important role in industrial manufacturing or in ordinary life,such as construction of bridges and railways,design of precision machine tools,shipbuilding and other engineering fields,high-precision and adaptable to complex working environments.Displacement sensors are of paramount importance in ensuring the quality of the project.In order to achieve accurate measurement of line displacement in a complex working environment,a magnetostrictive line displacement sensor is derived.The magnetostrictive linear displacement sensor excites the ultrasonic guided wave inside the waveguide material through the magnetostrictive effect of the ferromagnetic material.By analyzing the ultrasonic guided wave time information,the purpose of calculating the line displacement is achieved.Since the core of the magneto-acoustic transducer is in a magnetic structure,the advantage of the magnetostrictive transducer is that the inside of the transducer can be non-contact and does not require a coupling structure,which can greatly improve the service life of the sensor.Since the information of the magnetostrictive displacement sensor is transmitted by ultrasonic guided waves,the sound is more suitable for working in harsh environments and is not affected by oil,smoke and other factors.Therefore,the sensor can replace the working environment to a certain extent.More demanding grating line displacement sensor.In this paper,a linear displacement sensor with relatively simple structure and high precision is designed based on magnetostrictive theory.The design process mainly includes:the distance of the bias magnetic field in the electromagnetic ultrasonic transducer and the distance between the coil and the permanent magnet through PCdisp and COMSOL simulation software.The core parameters such as relationship,coil width and excitationfrequency are simulated and experimented to obtain the optimal parameters.According to the magnetostrictive transducer design corresponding excitation and receiving circuit,the excitation coil can provide high frequency narrowband pulse signal.The receiving end is an amplifying circuit with impedance matching function.The signal is processed by the guided wave receiving signal,and the signal is matched and filtered by the chirping function.The filtered guided wave signal is calculated by the cross-correlation algorithm to calculate the transit time,thereby obtaining the displacement of the line to be tested.Through experimental verification,the accuracy of the magnetostrictive linear displacement sensor designed in this paper can reach 0.1 mm,the error rate is controlled within one percent,and the range can reach 2m,which satisfies the sensor design standard.