Circuit And Experiment Research On Ultra-sonic Oil Film Thickness Measurement

In machine equipment,the working reliability and service life of relative moving parts are largely determined by the lubrication condition between their interfaces.Too thick and too thin oil film will bring adverse effects.Therefore,online monitoring of oil film thickness has important engineering application value.In view of the advantages of non-invasion,strong penetration and good directivity of ultrasonic wave,this paper adopts ultrasonic reflection coefficient method to measure the thickness of oil film in a typical three-layer medium.This paper mainly completed the establishment of theoretical model,single-channel measurement system design,ultrasonic array measurement system design,experimental verification,etc,and finally realized the static measurement of film thickness.The measurement error is within 5%,which proves the correctness of the theoretical model and the feasibility of the ultrasonic film thickness measurement system.1.According to the propagation theory of normal incidence of ultrasonic waves in three-layer medium,the resonance model and spring model for measuring different oil film thicknesses are established,and the methods of measuring oil film thickness by two models and the limitations of measurement methods are given.2.The ultrasonic emission circuit based on ARM is designed.Three driving schemes are realized,which include control,human-computer interaction,communication and upper computer software operation.The system integration of each hardware module facilitates unified management and control.Measurement system software is designed,including the control module software based on ?C/OS-II operation system and the upper computer serial port control software based on MFC.3.Based on the oblique incidence ultrasonic propagation model,the corresponding oil film thickness calculation method is deduced.Four-channel ultrasonic array film thickness measurement system is implemented based on single channel expansion.The hardware and software design is completed according to the principle of ultrasonic array measurement and data processing algorithm.The joint test of hardware and software of four-channel array system is realized.4.The experimental system is constructed to measure and verify the given oil film thickness,and the experimental results are good.