自适应特征选择的多扩张卷积网络轴承故障诊断

Bearing Fault Diagnosis Based on Multi-dilated Convolutional Networks with Adaptive Feature Selection

  • 摘要: 针对现有多尺度卷积网络模型缺乏故障判别机制,忽视不同卷积尺度大小对模型提取特征的影响,且多数依据电流信号诊断轴承故障网络模型的可解释性差的问题,提出自适应特征选择的多扩张卷积神经网络(Multi-dilated Convolutional neural networks with Adaptive Feature Selection,MCAFS)滚动轴承故障诊断方法。首先,采用解调技术和快速傅里叶变换(fast Fourier transform,FFT)对原始电流信号进行预处理,在抑制电流信号基频分量干扰的同时将解调信号从时域信号变换为频域信号;其次,使用标准卷积神经网络提取频域信号中的浅层特征;再次,利用不同核尺度的并行扩张卷积(parallel dilated convolution,PDC)块从浅层特征中提取多尺度特征;然后,提出改进的多尺度扩张卷积注意力(Multiscale dilated Convolutional Attention,MCA) 模块,自适应选择卷积尺度的大小,进一步选取深层次特征;最后,引入空间注意力模块(spatial attention module,SAM)将输入频域信号的注意分布可视化,从而提高网络的可解释性。通过帕德博恩滚动轴承数据集的电流信号对所提网络模型进行验证。实验结果表明,所提网络模型能够自适应地选择卷积尺度大小,有效地从输入数据中定位到关键信息,为电流信号诊断轴承故障的特征提取过程提供一定的可解释性意义。

     

    Abstract: The existing multi-scale convolutional network models lack a fault discrimination mechanism and ignore the influence of different convolution scales on the extracted features of the model. Furthermore, most of the neural network models based on current signals for bearing fault diagnosis are poor in interpretability. Aiming at solving these problems, a bearing fault diagnosis method based on Multi-dilated Convolutional neural network with Adaptive Feature Selection (MCAFS) is proposed. Firstly, the demodulation techniques are used to suppress the interference of the fundamental frequency component of the original current signal, and then the fast Fourier transform (FFT) is employed to convert the demodulated signal from the time domain to the frequency domain. Secondly, the shallow features are extracted from the frequency domain through a standard convolutional neural network. Next, multi-scale features are selected from shallow features using parallel dilated convolution (PDC) blocks with different kernel scales. Then, an improved multiscale dilated convolutional attention (MCA) module is proposed to adaptively select the size of the convolution scale and extract the deep features. Finally, the spatial attention module (SAM) is introduced to visualize the attention distribution of the input frequency signal, which further improves the interpretability of the network. The proposed network model is verified by the current signals of the Paderborn rolling bearing dataset. The experimental results show that the proposed network model can adaptively select the convolution scale, effectively locate the key information of the input data, and provide certain interpretable significance for the feature extraction process of current signal-based bearing fault diagnosis.

     

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