多特征融合的滚动轴承故障诊断

    Fault diagnosis of rolling bearings using multi-feature fusion

    • 摘要: 针对滚动轴承变工况条件下卷积神经网络在特征提取过程中无法充分提取全局特征信息的问题,该研究提出一种MSCNN-SwinT滚动轴承故障诊断方法。首先,在数据处理模块中利用连续小波变换(continuous wavelet transform, CWT)将一维振动信号转化为二维时频图像,以保留原始信号的时频特性;然后,在局部感知模块中利用多尺度卷积神经网络(multiscale convolutional neural networks, MSCNN)对故障信息的局部特征进行提取,并使用卷积块注意模块(convolutional block attention module, CBAM)提取关键信息;进一步构建特征提取模块,引入残差连接提高前后特征信息的利用效率,通过SwinT网络(swin transformer)学习故障信息的全局特征;最后使用全局平均池化代替全连接层进行故障识别。使用美国凯斯西储大学轴承数据集与自制数据集进行试验验证,试验结果表明,本文方法在可视化试验中的故障识别准确率为99.67%,在变工况试验中的故障识别准确率为95.01%~99.66%,不同编码方式试验中的故障识别准确率为100%。在自制数据集中,故障诊断准确率达到99.18%。与CWT-LeNet5、CWT-VGG16、CWT-ResNet18和CWT-SwinT相比,本文方法在变工况条件下的平均故障识别准确率分别提高8.79、8.64、3.49和3.18个百分点,在自制数据集中分别提高5.23、2.74、1.40和1.26个百分点。本文方法实现了变工况等复杂条件下滚动轴承不同故障状态的识别,能够充分提取轴承故障的全局特征信息,具有较高的故障诊断准确率和良好的泛化能力,可为变工况条件下的滚动轴承故障诊断提供参考。

       

      Abstract: A rolling bearing is one of the most important components in the rotating machinery and equipment of agricultural production. Most rolling bearings can often operate under complex conditions, such as strong noise and variable working conditions. It is very necessary to fully extract the characteristics of the fault signal in the process of fault diagnosis of rolling bearings. However, the convolutional neural network cannot fully extract the global feature information during the feature extraction under variable working conditions of rolling bearings. In this study, a multiscale convolutional neural network (MSCNN) - swin transformer (SwinT) was proposed for the rolling bearing fault diagnosis. Firstly, the continuous wavelet transform (CWT) was used in the data processing module to convert the one-dimensional vibration signal into a two-dimensional time-frequency image, which retained the time-frequency characteristics of the original signal. Secondly, the MSCNN was used to extract the local features of fault information in the local perception module. Then, the key information was extracted by the convolutional block attention module (CBAM). As such, the feature extraction module was further constructed. The residual connection was introduced to improve the utilization efficiency of the feature information before and after extraction. The global features of fault information were learned using the SwinT network. Finally, the global average pooling was used instead of the fully connected layer for fault identification. The bearing dataset was collected from the Case Western Reserve University and the self-made experimental data for the experimental verification. The test results showed that the fault identification accuracy in the visualization, variable working condition, and the test of different coding tests were 99.67%, 95.01%-99.66%, and 100%, respectively. The accuracy of fault diagnosis reached 99.18% in the self-made experimental datasets. Compared with the CWT-LeNet5, CWT-VGG16, CWT-ResNet18 and CWT-SwinT, the average fault identification accuracy was improved by 8.79, 8.64, 3.49, and 3.18 percentage points, respectively in the variable working condition test, while by 5.23, 2.74, 1.40, and 1.26 percentage points in the self-made experimental data set, respectively. The accurate and rapid identification was realized in the different fault states of rolling bearings under complex conditions, such as variable working conditions. The global characteristic information of bearing faults was fully extracted with high fault diagnosis accuracy and better generalization ability. This finding can also provide a strong reference for the rolling bearing fault diagnosis under variable working conditions.

       

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