基于树形决策卷积神经网络的滚动轴承故障分层诊断

    Hierarchical Fault Diagnosis for Rolling Bearings Based on Convolutional Neural Network With Tree Decision Layer

    • 摘要: 针对传统滚动轴承故障诊断中故障层次信息利用不充分、诊断精度不足的问题, 提出一种带有树形决策层的卷积神经网络(convolutional neural network, CNN)方法以实现故障位置与严重程度的逐层诊断。该模型同时具备CNN的特征提取能力和决策树的层次结构及分层决策特性。首先, 采用共享网络层和2个任务特定的分支全连接层分别提取与故障位置和故障严重程度有关的特征; 然后, 将2个全连接层的分类结果输入到树形决策层, 并使用加权层次分类损失调整模型权重参数, 从而实现模型对故障层次信息的自学习; 最后, 应用帕德博恩大学轴承数据集进行算法性能测试。实验结果表明, 该模型的平均分类准确率可达99.15%, 与领域内其他的诊断模型相比, 实现了更准确的故障位置和严重性的分类。

       

      Abstract: To address under-utilization of the prior knowledge provided by the hierarchical fault information and low diagnostic accuracy resulting from ignoring the hierarchical relationship between fault location and fault severity, an integrated model that combines convolutional neural network (CNN) with the tree decision layer for bearing faults diagnosis is proposed. The fault location was first judged, and the fault severity was then judged based on that. The proposed integrated model leveraged both the feature extraction capability of CNN and the hierarchical structure and decision-making characteristics of decision tree. First, a shared network backbone and two task-specific branching fully connected layers were utilized to extract features related to fault location and fault severity. Second, the tree decision layer was introduced to integrate their classification results, and then the weights of the model were adjusted using a weighted hierarchical classification loss generated by the tree decision layer, so as to learn the hierarchical information of bearing fault diagnosis. Finally, the effectiveness and performance of the proposed model were validated based on the Paderborn University bearing datasets. Results show that the proposed model can achieve an average classification accuracy of 99.15%. Compared with the existing diagnostic models in the field, the proposed model can achieve more accurate fault location and severity classification.

       

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