Method for extracting fault feature of antifriction bearing based on sliding entropy-ICA algorithm

A technology of fault characteristics and extraction methods, applied in mechanical bearing testing, mechanical component testing, machine/structural component testing, etc., can solve problems such as inability to accurately predict fault results, complex working environment, and small structures

Inactive Publication Date: 2017-08-08
HARBIN UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] As one of the commonly used parts in rotating machinery, rolling bearings are also one of the most easily damaged parts due to their small structure and large load capacity. They are often used as the main monitoring object for mechanical fault diagnosis. Due to the advantages of rich information and convenient collection, signal processing and analysis of vibration signals is one of the important means of bearing fault diagnosis commonly used at present. However, the working environment is complex during mechanical operation, and the measured signals collected by vibration sensors are usually many The result of the mutual coupling of two source signals, and the transmission path of the sensor will also interfere with the fault information of the signal, especially in the early stage of the bearing fault, the fault information is weak, which increases the difficulty of bearing signal feature extraction, and the extracted feature parameters will appear virtual. Disadvantages such as high alert rate
[0005] In general, the more complex the machine, the more the number of source signals, and considering the cost control in practical applications, the number of sensors used to collect vibration signals of rolling bearings is often smaller than the actual number of

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  • Method for extracting fault feature of antifriction bearing based on sliding entropy-ICA algorithm
  • Method for extracting fault feature of antifriction bearing based on sliding entropy-ICA algorithm
  • Method for extracting fault feature of antifriction bearing based on sliding entropy-ICA algorithm

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Embodiment approach 1

[0080] will be like image 3 The bearing vibration data experiment platform shown in the figure collects single-channel measured signals of four bearing states. The sampling frequency is 20kHz, the bearing model is Rexford ZA-2115, the spindle speed is 2000r / min, and the time domain of the four state signals is Waveform diagram such as Figure 4 As shown, the vibration signals of the four states are decomposed by EMD, and the obtained IMF separation theories are mutually orthogonal and independent, which meets the fact that the actual signals collected by multiple sensors are independent of each other. The steps of EMD decomposing the single-channel measured signal are as follows:

[0081] (1) Split the single-channel measured signal x(t) into the sum of the first-order intrinsic mode function and its residual term, expressed as the following formula:

[0082] x(t)=imf 1 (t)+r 1 (t)

[0083] where r 1 (t) is the residual component of the first-order intrinsic mode functio...

Embodiment approach 2

[0088] According to the n IMF components described in Embodiment 1, the effective IMF components are screened using the sliding entropy correlation coefficient; the sliding entropy correlation coefficient can be used to judge the similarity between two signal components, and the larger the result, the correlation between the two signals The higher the degree; using the sliding entropy correlation coefficient, we can judge the similarity between each IMF component in the EMD decomposition and the original signal component, and then judge the effective virtual channel signal. The calculation steps of the sliding entropy correlation coefficient between the signal x(n) and the IMF component are as follows Shown:

[0089] (1) signal x (n) is divided into k segment length l=20 equally divided length signal segments;

[0090] (2) with x i , i=0,1,2,...,n-l+1 as the starting point, intercept l time series sequentially backwards, use the formula to calculate the entropy value H(i) of ...

Embodiment approach 3

[0099] According to the effective IMF component described in Embodiment 2, it and the single-channel measured signal x(n) form a mixed signal matrix X(t)=[x 1 (t), imf i (t), imf i+1 (t)...], use the FastICA algorithm to perform blind source separation, and obtain the estimated value of the source signal y(t) as Figure 5 As shown, the specific steps of the FastICA algorithm are as follows:

[0100] (2) Preprocessing the observed signal: mainly data centralization and whitening processing; centralization refers to the mean value processing of the signal, that is, subtracting the mean value of the signal sample from each signal sample to obtain:

[0101]

[0102] Signal whitening refers to the linear transformation of the centered observed signal X(t) make The covariance matrix of is a diagonal matrix, so as to remove the correlation between observations; the purpose of centering and whitening is to make the separation matrix W must exist WW T =1, and reduce the param...

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Abstract

A method for extracting the fault feature of an antifriction bearing based on a sliding entropy-ICA algorithm is provided. The method comprises main steps of: (1) subjecting a single-channel actually measured signal to EMD to obtain respective IMF components; (2) screening out effective IMF components by using a sliding entropy cross correlation coefficient to form a virtual channel signal; (3) integrating the single-channel actually measured signal with the effective IMF components to form a composite signal matrix, separating the composite signal matrix by using a FastICA algorithm to obtain respective source signal estimated values; (4) retaining a source signal containing a bearing fault feature, and extracting a plurality of time-domain feature parameters and frequency-domain feature parameters to form a feature parameter set; and (5) subjecting a high-dimensional feature set to data fusion by using an LLE algorithm to obtain an accurate low-dimensional feature parameter. The method uses the sliding entropy-ICA algorithm in combination with the LLE algorithm, is suitable for extracting the fault feature of rotating machines including the antifriction bearing, and can extract the source signal containing fault information just by using the single-channel signal. The low-dimensional feature parameter obtained by the method can describe bearing fault information.

Description

[0001] Technical field: [0002] The invention relates to the field of mechanical fault diagnosis, in particular to a method for extracting fault features of rolling bearings. [0003] Background technique: [0004] As one of the commonly used parts in rotating machinery, rolling bearings are also one of the most easily damaged parts due to their small structure and large load capacity. They are often used as the main monitoring object for mechanical fault diagnosis. Due to the advantages of rich information and convenient collection, signal processing and analysis of vibration signals is one of the important means of bearing fault diagnosis commonly used at present. However, the working environment is complex during mechanical operation, and the measured signals collected by vibration sensors are usually many The result of the mutual coupling of two source signals, and the transmission path of the sensor will also interfere with the fault information of the signal, especially ...

Claims

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Application Information

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IPC IPC(8): G01M13/04
CPCG01M13/045
Inventor 隋秀凛邹运奇葛江华
Owner HARBIN UNIV OF SCI & TECH
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