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Rolling bearing fault diagnosis method based on fft and fully connected layer-svm

A fully connected layer, rolling bearing technology, used in the testing of mechanical parts, the testing of machine/structural parts, instruments, etc., can solve the problems of long time consumption of detection algorithms, slow model convergence speed, and different lifespan, etc. The effect of training speed and judgment classification accuracy, parameter optimization time reduction, and detection time reduction

Active Publication Date: 2022-06-21
王萌
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Rolling bearings are not only widely used in production, rolling bearings are also vulnerable parts in mechanical equipment. According to statistics, about 30% of the faults in rotating machinery are caused by rolling bearing failures; after using fault diagnosis technology, the probability of mechanical equipment failure can be extremely high The reduction of maintenance cost is 25%-50% less than before; due to the long life of the rolling bearing, according to the national standard, there is a 90% reliability threshold as a standard part, even if the same material is used on the same machine with the same process The same batch of bearings is produced, and its service life is also different; usually in reality, regular inspection and repairs are carried out based on the designed fatigue life, which has a great chance of damaging the equipment and causing economic losses;
[0004] At present, in the practice of enterprises, if it is a rolling bearing in an unimportant occasion, it mainly depends on the experience of engineers and technicians to judge whether there is a fault in the operation of the bearing through touch and hearing; in more important occasions, it is necessary to regularly disassemble and check the operation of the bearing However, it is impossible to predict the fault state in a timely and effective manner; the current detection algorithms for bearing fault defects mainly focus on the traditional use of time domain and frequency domain signals as signal input features, and then use machine learning or deep learning methods for classification, with high accuracy , however, it does not meet the requirements of the industrial detection application of core components; at the same time, the current detection algorithm for bearing fault defects consumes a relatively long time, and the model convergence speed is too slow

Method used

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  • Rolling bearing fault diagnosis method based on fft and fully connected layer-svm
  • Rolling bearing fault diagnosis method based on fft and fully connected layer-svm
  • Rolling bearing fault diagnosis method based on fft and fully connected layer-svm

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0079] In order to prove the effectiveness of this method, the bearing vibration data is used from the open data set of Case Western Reserve University in the United States. In this experiment, the bearings at the drive end of the motor and the fan end are used as the diagnostic objects, and the inner ring, rolling element and The single point damage is introduced on the outer ring by EDM to simulate three kinds of faults of the bearing. The fault damage scales are 0.007inch, 0.014inch and 0.021inch respectively, and then under similar working conditions (equal load, close to rotating speed) , the fault signal collected by the acceleration sensor on the upper side of the motor drive end, the sampling frequency is 12kHz. According to the location and size of the bearing fault, the categories of bearings are divided into ten categories, with 1024 data points as a sample, of which 1600 samples are selected for each category (800 samples are selected for the drive end and 800 sampl...

Embodiment 2

[0087] The validity of the method of the present invention is verified below using experimental data of rolling element failures in rolling bearings:

[0088] Step 1: Select a rolling bearing with a faulty rolling element, so that at the same working speed, use an acceleration sensor to detect the vibration signal of the rolling element on the rolling bearing, and use the collected vibration signal respectively using the data processing method of the present invention. Process the vibration signal data with the convolutional neural network in the prior art;

[0089] Step 2: After processing, the original time-domain and frequency-domain vibration signals of the data processing results are displayed with time-varying spectrograms. figure 2 As shown, the time-varying spectrogram of the original time-domain vibration signal processed by the traditional convolutional neural network method is shown in image 3 shown;

[0090] we start from figure 2 It can be seen that the freq...

Embodiment 3

[0093] The following uses the fault bearing to carry out a comparative test on the fault detection methods of different rolling bearings, and further verify the detection method of the present invention:

[0094] Step 1: Select a set of rolling bearing data, and the failure conditions of the bearings are shown in Table 1:

[0095] Table 1: Fault information for rolling bearings

[0096]

[0097] Step 2, respectively use time-frequency feature+SVM, EMD+SVM, wavelet+SVM, CNN-SVM and FFT (fast Fourier transform)+FC (full connection layer)+SVM (support vector machine) of the present invention, etc. The diagnostic method detects the faulty bearing described in step 1, and compares the detected results with the data in Table 1 above, and the comparison results of the time-consuming and accuracy of each detection method are shown in Table 2:

[0098] Table 2: Comparison of accuracy and time consumption of different methods

[0099]

[0100] It can be seen from the results in ...

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Abstract

The invention discloses a rolling bearing fault diagnosis method based on FFT and fully connected layer-SVM, including the extraction, transformation, normalization and other processes of vibration signals of the rolling bearing under normal conditions, inner ring faults, outer ring faults, and rolling body faults; The rolling bearing fault detection method does not rely on the convolutional neural network when detecting rolling bearings, it only needs to train the SVM classifier and the fully connected layer to complete, and the parameters of the classifier do not need to be optimized by the algorithm, which can improve the training of the model Speed ​​and classification accuracy rate; Simultaneously the method of the present invention has only one layer of fully connected layer, does not need the convolution kernel operation of convolutional neural network, makes its parameter optimization time greatly reduce, experimental result proves, the method of the present invention measures The accuracy rate of rolling bearing faults reaches 100%, the detection time is shortened by more than 80%, and it has the characteristics of high classification accuracy and fast fault diagnosis speed.

Description

technical field [0001] The invention belongs to the technical field of fault diagnosis, and in particular relates to a fault diagnosis method of a rolling bearing based on FFT and fully connected layer-SVM. Background technique [0002] Modern industrial production requires very close production rhythm. Once mechanical equipment fails, it will disrupt the production process, causing huge economic losses and even casualties. Today, large-scale production relies more on highly reliable production and processing equipment, and mechanical fault diagnosis has become a A rapidly changing engineering technology; [0003] Rolling bearings are not only widely used in production, rolling bearings are also wearing parts in mechanical equipment. According to statistics, about 30% of the failures in rotating machinery are caused by rolling bearing failures; after using fault diagnosis technology, the probability of mechanical equipment failure can be extremely high. The maintenance cost...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01M13/045
CPCG01M13/045
Inventor 王萌曾艳彭飞赵红美毕胜王康
Owner 王萌