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Doppler distorted acoustic signal correction method based on microphone array

A microphone array and acoustic signal technology, which is applied in the field of fault diagnosis and acoustic fault diagnosis of rail-side train bearings, can solve the problems of reduced practicability, long calculation time, large calculation amount, etc. small amount of effect

Active Publication Date: 2016-12-14
UNIV OF SCI & TECH OF CHINA
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Problems solved by technology

However, due to the complex coupling of the spindle system, it is basically impossible to obtain this characteristic frequency in practical applications, which greatly reduces its practicability
Another kind of correction method based on multi-parameter matching of geometric model, although avoiding the prior condition of bearing characteristic frequency, due to the large amount of calculation and long calculation time, this method is not suitable for practical systems

Method used

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  • Doppler distorted acoustic signal correction method based on microphone array
  • Doppler distorted acoustic signal correction method based on microphone array
  • Doppler distorted acoustic signal correction method based on microphone array

Examples

Experimental program
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Effect test

Embodiment 1

[0040] The fault signal of bearing outer ring with Doppler distortion is processed. The signal is collected by an equidistant microphone line array, the array element spacing is 0.1m, and the number of array elements is 4. The vertical distance between the microphone array and the sound source is 2m, and the sound velocity is 340m / s. The bearing model of the outer ring fault is NJ(P)3226X1, and the parameters are shown in Table 1.

[0041] Table 1: Specification parameters of train bearing NJ(P)3226X1 (unit: mm)

[0042]

[0043] The signal sampling rate is 25.6kHz, and the rotation speed is 576r / min. At this speed, the fault frequency of the outer ring of the bearing is f o = 55.9Hz.

[0044] image 3 (a) and image 3 (b) are the spectrum and envelope spectrum of the acquired signal, respectively. Due to the existence of Doppler distortion, the frequency spectrum and envelope spectrum of the signal are broadened and shifted, and the bearing fault cannot be diagnosed...

Embodiment 2

[0052] The fault signal of bearing inner ring with Doppler distortion is processed. Same as in Embodiment 1, the signal is collected by an equidistant microphone line array, the distance between array elements is 0.1 m, and the number of array elements is 4. The vertical distance between the microphone array and the sound source is 2m, and the sound velocity is 340m / s. The bearing model of the outer ring fault is NJ(P)3226X1, and the parameters are shown in Table 1. The signal sampling rate is 25.6kHz, and the rotation speed is 576r / min. At this speed, the fault frequency of the inner ring of the bearing is f i =78.5Hz.

[0053] Figure 5 (a) and Figure 5 (b) are the spectrum and envelope spectrum of the acquired signal, respectively. Due to the existence of Doppler distortion, the frequency spectrum and envelope spectrum of the signal are broadened and shifted, and the bearing fault cannot be diagnosed. Utilize the method for correcting the Doppler distortion acoustic...

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Abstract

The invention discloses a Doppler distorted acoustic signal correction method based on a microphone array. The Doppler distorted acoustic signal correction method can correct Doppler distortion in the acoustic signal detected by a rail edge acoustic diagnosis system, and accurate diagnosis of train bearing faults can be achieved. The Doppler distorted acoustic signal correction method comprises carrying out Hilbert transformation to a detection signal, obtaining a complex signal, windowing the complex signal, obtaining a signal segment, calculating the acceptance angle corresponding to each signal segment, constructing a resampling time sequence in dependence on the relationship between the emission time and the reception time, carrying out cubic spline difference value resampling to a signal acquired a microphone in the center of the array, carrying out Hibert transformation and fast Fourier transform to a correction signal, and carrying out diagnosis. Compared with a conventional method based on a single microphone, the Doppler distorted acoustic signal correction method based on the microphone array is advantaged in that the algorithm is simple, the calculated amount is low, prior knowledge is not needed, noise robustness is good and the like, and the Doppler distorted acoustic signal correction method has obvious advantages in practical application.

Description

technical field [0001] The invention relates to a method for correcting Doppler distortion acoustic signals based on a microphone array, which is suitable for the field of fault diagnosis, especially for the field of acoustic fault diagnosis of trackside train bearings. Background technique [0002] Faulty train bearings excite a periodic transient acoustic signal. Therefore, the non-contact fault diagnosis and state monitoring of the train bearing can be realized by detecting the acoustic signal. However, due to the relative movement between the train bearing and the microphone, the measured acoustic signal has spectrum expansion and moving Doppler distortion, which brings difficulties to the fault diagnosis of the train bearing. Therefore, correcting the Doppler distortion and eliminating the spread and movement in the spectrum are the prerequisites for accurate diagnosis of train bearing faults. [0003] The traditional Doppler correction method based on single micropho...

Claims

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Application Information

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IPC IPC(8): G01M13/04
CPCG01M13/045
Inventor 张尚斌何清波
Owner UNIV OF SCI & TECH OF CHINA
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