Vibration signal conversion method based on vibration intensity low frequency filtering correction

Abstract

The invention provides a vibration signal conversion method based on vibration intensity low frequency filtering correction; the method comprises the following steps: 1, continuously valuing a band-pass filter lower-cut-off-frequency fd in a limited scope section, respectively making frequency domain first integral for a vibration acceleration signal, thus obtaining a vibration speed signal; 2, calculating vibration intensities of the vibration speed signal under different fd conditions, and drafting a vibration intensity relation curve relative to the fd; 3, determining the corresponding minimum cut-off-frequency fmin when the vibration intensity suddenly changes according to the relation curve; 4, setting the upper-cut-off-frequency of the band pass filter according to real demands, enabling the lower-cut-off-frequency fd=fmin and carrying out low frequency filter correction, respectively making frequency domain first and second integrals for the vibration acceleration signal, thus obtaining a vibration speed and vibration displacement signal. The method can effectively solve the low frequency sensitivity and accumulation error amplification effect of conventional frequency domain integral, and can be applied to precision conversion of different types of vibration signals.

Description

technical field [0001] The invention relates to the field of vibration signal processing, in particular to a vibration signal conversion method based on vibration intensity low-frequency filter correction. Background technique [0002] In mechanical fault diagnosis and condition monitoring, three vibration parameters, acceleration, velocity and displacement, are commonly used. However, in the actual test of mechanical vibration signals, due to the limitations of equipment or test environment, the measurement of vibration velocity and vibration displacement is usually difficult and complicated, and the acceleration sensor is small in size, light in weight, wide in frequency range, easy to install, etc. The advantages have been more widely used. However, in many industries, vibration velocity and vibration displacement information are often required. Therefore, in many engineering practices, the problem of vibration signal type conversion is involved, that is, the vibration ...

AI Technical Summary

Problems solved by technology

However, although the traditional frequency-domain integration with Fourier transform as the core is relatively mature in theory, in practical applications, due to the influence of factors such as noise interference and low-frequency trend items, large low-frequency oscillations and peak errors often occur, which has Low frequency sensitivity, there is still room for further improvement in the accuracy of calculation results

However, the low frequency band is also the frequency band where the accuracy of the acceleration sensor is very poor, so the interference in the low frequency band is a main source of error in the traditional frequency domain integration

At present, the commonly used method is to directly set the components below a certain frequency to zero on the spectrum to remove the trend item. This method is very simple in analysis and operation, but it is difficult to define the lower limit cut-off frequency in the application.

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