Non-contact torsional vibration measurement method based on machine vision

Abstract

The invention provides a non-contact torsional vibration measurement method based on machine vision. The method comprises the steps of performing high-speed video acquisition on a torsional vibrationobject by using a computer vision technology, realizing separation, extraction and amplification of torsional vibration signals by using a 'micro motion amplification 'principle, and calculating the instantaneous frequency of the torsional vibration signals by using Fourier transform, wavelet transform and other technologies. According to the method provided by the invention, the torsional vibration time domain signals can be accurately extracted, and the torsional vibration frequency and period can be obtained. And the method is still effective to a tiny torsional vibration system. The methodhas the characteristics of being non-contact, high in test efficiency and only short in video acquisition time. Only a camera and lighting equipment are needed, a sensor and a data acquisition systemare not needed, mark points do not need to be pasted on the surface of the torsional vibration object, and accuracy and reliability are good. According to the method provided by the invention, the state of the shaft system of a rotary machine can be monitored. For a turntable system or a slender structure, the rotational inertia of the system, the shear modulus of the material and the like can becalculated.

Description

technical field [0001] The invention belongs to the technical field of non-contact measurement, in particular to a non-contact torsional vibration measurement method based on machine vision. Background technique [0002] Torsional vibration is one of the basic vibration forms of shafting, discs and other objects. During the rotation of the shafting system, fast and sometimes slow shafting torsional vibration cannot be avoided. Excessive torsional vibration will cause excessive vibration and noise of the transmission system. Therefore, the measurement of torsional vibration is one of the important contents of mechanical system detection. At present, most of the mechanical vibration sensors (acceleration sensors, laser vibrometers) are suitable for linear vibration, but not for torsional vibration measurement. At present, there are two types of torsional vibration measurement commonly used in engineering: one is contact measurement, for example, a resistive strain gauge is pa...

AI Technical Summary

Problems solved by technology

However, the above dedicated non-contact measuring devices are too complicated and expensive, making the application cost higher

In addition, another disadvantage of the above two methods is that the measurement point is single

Although the principle of torsional vibration measurement based on CCD camera technology has been invented in the past, such as Xu Minqiang proposed to use CCD camera technology to measure the torsional vibration of steam turbines, but the inventive method still needs to paste a paper tape with a pattern on the shafting of the steam turbine

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