Differential ultrasonic low frequency vibration measuring device and method

Abstract

The invention discloses a differential ultrasonic low frequency vibration measuring device and a method. The device comprises fixing flat plates 1 and 2, a mass block, support springs 1 and 2, two ultrasonic emission sensors 1 and 2 and two ultrasonic receiving sensors 1 and 2. The method comprises the following steps that a FPGA generates an ultrasonic signal with a high stabilization degree and a sampling sequence signal; parallel whole period sampling is performed on emission signals and receiving signals of the ultrasonic emission sensors 1 and 2 and the ultrasonic receiving sensors 1 and 2; through a Fourier transform (FT) and an inverse Fourier transform (IFT), an ultrasonic fundamental frequency signal is extracted and ultrasonic sampling data without high-frequency interference is acquired; calibration is performed on distances x1 and x2 between the mass block and the fixing flat plates 1 and 2, phase differences phi1 and phi2 between the ultrasonic emission sensors 1 and 2 and the ultrasonic receiving sensors 1 and 2 respectively and an ultrasonic wavelength value lambda 0 so that an actual displacement value d of the mass block under any temperature condition is acquired.

Description

technical field [0001] The invention relates to the field of vibration measurement, in particular to a differential ultrasonic low-frequency vibration measurement device and method. Background technique [0002] At present, the commonly used low-frequency vibration measurement mainly uses magnetoelectric displacement sensors, which are susceptible to electromagnetic interference, and the lowest frequency of measurement is limited. Although the frequency can be extended by the servo method, the sensitivity is reduced at the same time. Using differential ultrasonic to measure low-frequency vibration can not only achieve higher sensitivity, but also measure vibration signals as low as 0 frequency. [0003] When measuring with ultrasonic waves, temperature changes have a great influence on the measurement results. The traditional method is to set a temperature sensor during measurement, and correct the wavelength according to the relationship between temperature and wavelength....

AI Technical Summary

Problems solved by technology

The traditional method is to set a temperature sensor during measurement, and correct the wavelength according to the relationship between temperature and wavelength. This method requires high temperature measurement accuracy and the measurement circuit is relatively complicated.

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