Mechanical fault feature extraction method based on wavelet transform and topological data analysis

A wavelet transform and topology data technology, applied in the field of feature extraction, can solve the problems of learning the nonlinear relationship, complexity and instability of fault data, and achieve the effect of improving the classification accuracy.

Active Publication Date: 2021-08-03
SHANDONG UNIV
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Problems solved by technology

[0004] However, on the one hand, the diagnostic performance of most traditional methods depends largely on the quality of the extracted and selected features. In engineering practice, the collected vibration signals are always data-heavy, complex and unstable, and noisy very big
Not only that, but in most cases, feature selection largely depends on the engineering experience of diagnostic experts. For complex and large data sets, it becomes very difficult to use expert experience to make useful assumptions.
On the other hand, it is difficult for shallow learning models to effectively learn complex nonlinear relationships among fault data.

Method used

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  • Mechanical fault feature extraction method based on wavelet transform and topological data analysis
  • Mechanical fault feature extraction method based on wavelet transform and topological data analysis
  • Mechanical fault feature extraction method based on wavelet transform and topological data analysis

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Embodiment 1

[0052] A mechanical fault feature extraction method based on wavelet transform and topological data analysis, comprising the following steps:

[0053] 1. Select the original mechanical vibration data as the training set, perform wavelet transformation on each sample in the training set, and convert the time-domain diagram of the original mechanical vibration signal into a corresponding time-frequency diagram;

[0054] Wavelet transform is a technique aimed at the non-stationary characteristics of signals, which can well reflect the correlation characteristics of signals. Wavelet transform is a time-frequency analysis method with a fixed window size, but the shape of the window can be changed to make it multi-resolution. Wavelet transform has the ability of local analysis in time domain and frequency domain, and is widely used in the diagnosis of mechanical parts.

[0055] The formula of wavelet transform is as follows:

[0056]

[0057] Among them, α is the scale to contr...

experiment example 1

[0082] Taking the bearing fault vibration data set of Case Western Reserve University as an example, the method is described in detail.

[0083] Case Western Reserve data set contains vibration data under four different working conditions (0HP, 1HP, 2HP, 3HP), and also contains data of one normal state and three fault states (inner ring fault, outer ring fault, Rolling element faults), each fault is divided into different fault diameters, so there are nine fault types in the entire data set. In this embodiment, experiments are carried out on data sets with the same fault size and different loads. This solution can also use data of different fault sizes or different loads, this example is for reference only.

[0084] Step 1: Perform preprocessing on the original vibration training data. The preprocessing refers to segmenting the original vibration data set. Every 1024 data forms a sample data. Firstly, wavelet transform is performed on the original vibration data. Since there ...

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Abstract

The invention relates to a mechanical fault feature extraction method based on wavelet transform and topological data analysis, and the method comprises the steps: carrying out the feature analysis of an original signal through the wavelet transform and topological data analysis, carrying out the parallel fusion of two groups of features, and inputting the two groups of features into a subsequent classification network; on the one hand, wavelet transform analysis is adopted to consider the time domain and frequency domain characteristics of mechanical fault data, original vibration signals are analyzed from multiple scales, and better characteristics are extracted from non-stationary original time domain signals; on the other hand, topological data analysis is applied to the field of fault diagnosis, the deep topological relation between fault data sets and the shape in hidden data can be effectively mined out through the topological data analysis method under the influence of noise, more robust and more important data features are extracted, and the subsequent fault type classification accuracy can be improved.

Description

technical field [0001] The invention relates to a mechanical fault feature extraction method based on wavelet transform and topological data analysis, and belongs to the technical field of feature extraction. Background technique [0002] With the rapid development of science and technology, the functions of mechanical equipment in modern industry are becoming more and more complex. Fault diagnosis of mechanical equipment becomes the most critical aspect in system design and maintenance. Machine failures can cause huge financial losses and sometimes pose a threat to the people who use the machines. Fault diagnosis plays an important role in monitoring the relationship between data and machine health status, which has become a widespread concern in machine health management, where improving diagnostic accuracy is particularly important. In the fault classification step, feature extraction is the most critical part. Therefore, the quality of features extracted from mechanica...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/14G06K9/62G06N3/04G06N3/08G01H17/00G01M99/00
CPCG06F17/148G06N3/08G01M99/005G01H17/00G06N3/045G06F18/214G06F18/241G06F18/253
Inventor 李沂滨汪雨晴贾磊宋艳徐丹雅郑维红李沐阳张悦
Owner SHANDONG UNIV
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