A non-contact torsional vibration measurement method based on machine vision

Abstract

The invention proposes a non-contact torsional vibration measurement method based on machine vision, which uses computer vision technology to collect high-speed video of torsional vibration objects, and uses the principle of "micro motion amplification" to realize the separation, extraction and amplification of torsional vibration signals. The instantaneous frequency of the torsional vibration signal is calculated by techniques such as Liye transform and wavelet transform. The method proposed by the invention can accurately extract the torsional vibration time domain signal, and obtain the frequency and period of the torsional vibration. Still valid for tiny torsional vibration systems. The characteristics of this Fang Ming are non-contact, high test efficiency, and only need a short video acquisition time. Only cameras and lighting equipment are needed, no sensors and data acquisition systems are needed, and no marking points need to be pasted on the surface of torsional vibration objects, with good accuracy and reliability. According to the method of the invention, the condition monitoring of the shaft system of the rotary machine can be carried out. For a turntable system or a slender structure, the moment of inertia of the system and the shear modulus of the material can be calculated.

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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