SU1262295A1 - Method for contactless measurement of object vibrations - Google Patents

Abstract

The invention relates to a measuring technique and can be used to measure the parameters of mechanical vibrations of various objects, for example, to study the amplitude-frequency characteristic of a moving object. The aim of the invention is to increase the measurement accuracy by eliminating the influence of the reflective properties and shape of the object and the characteristics of the radiation and detection systems. According to the method, the object under study is probed with ultrasonic vibrations, receives a reflected signal, which due to the Doppler effect turns out to be frequency-modulated, mixes the probe and reflected signals, extracts two stable Doppler harmonics from the resulting total signal, and determines the power of these harmonics the amplitude of the oscillations is investigated (L of the object, and by the difference of their frequency, the frequency of the oscillations of the object. 1 Il.

Description

The invention relates to measuring technique and can be used to measure the parameters of mechanical vibrations of various objects, for example, to study the amplitude and frequency characteristics of a moving object.

The purpose of the invention is to increase the measurement accuracy by eliminating the influence of reflective properties and the shape of the object and characteristics of radiation and registration systems.

The drawing shows a device for implementing the method of non-contact measurement of object vibrations. 15 The device contains a probe signal emitter, a reflected signal receiver 2, a mixer 3 connected to a spekZ'r-Schnalizer 4 and two frequency-tunable 20 Nose filters 5 and 6, two logarithmic amplifiers 7 and 8, and a subtractor 9.

The method of non-contact measurement of object vibrations is carried out 25 as follows.

Using the emitter 1, sounding of an oscillating object of an ultrasonic wave with a frequency f _{0 is} carried out. thirty

Due to the Doppler effect, the reflected signal is frequency-modulated. This signal is received by the receiver 2 and mixed with the probing signal in the mixer 3. 35

The total signal is fed to the input of the spectrum analyzer 4, where the vibration frequency is determined '£ 2 = f _htl - f _n (where f „, f _{n + 1 are the} frequencies of the adjacent Doppler harmonics 40). Then, the bandpass filters 5 and 6 are tuned to the frequencies f _Λ and f _{n + 1} . Filtering the Doppler signal, amplification from the filtered signals by logarithmic amplifiers 7 and 8 and subtracting the amplified signals in the subtractor 9. The signal K is determined at the output of the subtractor 9. The magnitude of this signal is related to the amplitude of oscillations A _{about the} ratio

TO

/ A5_Ao_ch where 1 'is the Bessel function of the first row _with yes;

Ά- is the wavelength of the sounding signal;

e is the propagation velocity of the ultrasonic wave.

From the presented ratio determine the amplitude of the oscillations of the investigated object.

Claims (1)

The invention relates to a measurement technique and can be used to measure the parameters of the mechanical oscillations of various objects, for example, the day of the investigation of the amplitude-frequency characteristic of a motion; one cent of the object. The purpose of the invention is to improve the measurement accuracy by eliminating the influence of the reflective properties and shape of the object and the characteristics of the radiation and detection systems. The drawing shows a device for carrying out a method for contactless measurement of object oscillations. The device comprises an emitter 1 of probing signals, a receiver 2 of the reflected signal, a mixer 3 connected to the spectrum analyzer 4 and two tunable Nos. 1 and 2 by frequency band filters 5 and 6, two logarithmic amplifiers 7 and 8 and a subtractor 9. A method for contactless measurement of object vibrations is carried out as follows. With the help of the emitter 1, sounding of the oscillating object of the ultrasonic wave with a frequency of fj, is carried out. The reflected signal due to the Doppler effect is obtained frequency-modulated. This signal is received by receiver 2 and mixed with the sounding signal in mixer 3. The CsTF1arny signal is post-coupled to the input of the spectrum-analyzer 4, where the oscillation frequency Л ff ,, is determined (where f, f., The frequencies of the neighboring Doppler harmonics). Then the bandpass filters 5 and 6 are tuned to frequencies. The Doppler signal is filtered, the gain from 952 filtered signatures with logarithmic amplifiers 7 and 8, and the amplified signals are output in the subtractor 9. The signal K at the output of the subtractor 9 is determined. The magnitude of this signal is related with the amplitude of oscillation A, the ratio K Ig where I; - Bessel function of the first row; probing signal wavelength; ultrasonic wave propagation velocity. From the presented ratio, the amplitude of the object oscillations is determined. Claims of the method of non-contact measurement of an object's oscillations, which consist in probing an object under study by ultrasonic vibrations, receiving a modulated signal reflected from this object, mixing the probe and reflected signals, and determining the amplitude and frequency of the object's oscillations different from the parameters of the total signal, that, in order to improve the measurement accuracy by eliminating the influence of the reflective properties and shape of the object and the characteristics of the radiation systems, the registration Two adjacent Doppler harmonics, with respect to the power of these harmonics, determine the amplitude of the oscillations, 1 and, based on the difference between their frequencies, the oscillation frequency of the object.