A Method of Improving the Time-Frequency Conversion Accuracy of Shafting Torsional Vibration Signal
A shafting torsional vibration, time-frequency conversion technology, applied in the direction of measuring vibration, vibration measurement in solids, measuring devices, etc., can solve problems affecting the accuracy of test analysis, etc., to achieve accuracy, increase the number of sampling points, improve time The effect of frequency conversion accuracy
Active Publication Date: 2015-09-30
HARBIN ENG UNIV
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Although this can meet the accuracy requirements in most engineering measurements, for high-precision fault diagnosis, especially for early fault detection, this kind of equal-angle sampling cannot meet the accuracy requirements, affecting the accuracy of test analysis
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[0027] Below in conjunction with accompanying drawing, the present invention is described in more detail:
[0028] The present invention realizes the second sampling through isochronous linear interpolation of the acquired twist angle data.
[0029] First, the torsional vibration of the shaft system is measured by the toothed disc measuring device, and the time for the signal acquisition device to make one revolution of the shaft t c And the time t for rotating n teeth of the toothed disc (the total number of teeth of the toothed disc is N) n Collect; Calculate the torsion angle value according to the signal measured by the signal acquisition device, the formula is as follows:
[0030]
[0031] Among them, θ is the torsion angle value, ω is the instantaneous angular velocity, t c is the period of the final output signal, is the average angular velocity, N is the number of gear teeth, t n It is the time to output n square wave signals, n is the number of square waves, a...
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The invention provides a method for improving time frequency conversion accuracy of shaft torsional vibration signals. The method comprises the following steps of: measuring shaft torsional vibration, acquiring time tc for a shaft to rotate one circle and time tn for the shaft to rotate across n teeth of a gear disc by a signal acquisition device, calculating a torsional angle value by utilizing a torsional angle formula to obtain variation data of a torsional angle with the number of the teeth and finishing the first sampling of torsional angle signals; carrying out equaltime linear interpolation on the torsional angle data to obtain new torsional angle data, namely torsional angle data of equal time sampling, and finishing the second sampling of the torsional angle signals; and carrying out windowing processing on the torsional angle data acquired by second sampling first, and then carrying out FFT (Fast Fourier Transform) processing. In the invention, the first equal angle sampling is converted to the second equaltime sampling by the equaltime linear interpolation method, and therefore sampling frequency and sampling spots are improved; the FFT processing is carried out on the windowed data subjected to equaltime sampling, and therefore accuracy and reliability is achieved, and time frequency conversion accuracy of the shaft torsional vibration signals is improved.
Description
technical field [0001] The invention relates to a detection method of a shafting torsional vibration signal. Specifically, it is a method to improve the accuracy of time-frequency conversion of shafting torsional vibration signals. Background technique [0002] After the torsional vibration signal is collected by the torsional vibration instrument, when performing data processing and analysis, the obtained data will be processed by FFT for frequency domain analysis. However, in the standard FFT processing, the data should be obtained by sampling at the same time, while the traditional torsional vibration test equipment installs a gear plate on the shafting, collects the pulse signal with a magnetoelectric sensor, and then calculates the pulse width. and the shafting speed, that is, the generation of the signal is obtained through the triggering of the equiangular gear teeth, so the collected data points are equiangular. Due to the existence of torsional vibration of the sh...
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IPC IPC(8): G01H1/10
Inventor 李玩幽蔡鹏飞郭宜斌周海军吕秉琳
Owner HARBIN ENG UNIV