基于多尺度卷积类内迁移学习的列车轴承故障诊断

考虑变工况下列车轴承振动数据分布不一致情况下, 传统深度学习诊断模型的泛化能力下降, 提出了一种多尺度卷积类内自适应的深度迁移学习模型; 模型利用改进的ResNet-50网络分析振动数据的频谱, 得到了中间层次特征, 构造了多尺度特征提取器, 从不同尺度处理中间层次特征得到高层次特征; 将高层次特征作为分类器的输入, 同时计算了伪标签以缩短在不同工作条件下收集的振动信号的条件分布距离来进行类内匹配; 为了验证模型的通用性和优越性, 将提出的模型分别用于列车轮对轴承数据集和凯斯西储数据集的多个工况进行试验验证和分析。研究结果表明: 通过对齐不同域中同一类样本的高层次特征作为分类器的输入, 提出的模型获得了更为理想的故障诊断精度; 在列车轴承6个变工况诊断实例中, 平均诊断精度为90.75%, 与传统深度学习模型相比, 模型诊断精度平均提高了约10%, 召回率为0.927;在凯斯西储数据集的12个变工况诊断实例中, 模型平均诊断精度达99.97%, 比传统模型提高约10%。可见, 利用伪标签减小了不同域之间的条件分布差异, 很好地处理了源域和目标域数据分布不一致的问题; 多尺度特征提取器能从不同尺度对齐样本的高层次特征, 增强了模型的泛化性与鲁棒性, 是解决变工况列车轴承故障诊断问题的一种有效模型。 

Multi-scale convolution intra-class transfer learning for train bearing fault diagnosis

Considering the inconsistent distribution of bearing vibration data collected under different working conditions, the generalization ability of traditional deep learning model decreases. A multi-scale convolution intra-class adaptive deep transfer learning model was proposed. The spectrum of vibration data was analyzed using the modified ResNet-50. The middle-level features were obtained. A multi-scale feature extractor was developed, the middle-level features were processed, and the high-level features were generated. The high-level features were used as the inputs of classifier. The pseudo-labels were computed, and then the conditional distribution distances of vibration data collected under variable working conditions reduced for the intra-class adaptation. To verify the generality and superiority of model, the proposed method was employed to analyze a train wheelset bearing dataset and the Case Western Reserve University dataset under variable working conditions. Analysis result indicates that the high-level features of samples with the same label in different domains are properly aligned. More satisfactory fault diagnosis accuracies are obtained by the proposed model. In six fault diagnosis cases of train bearing under variable working conditions, the average diagnosis accuracy of the proposed model is 90.75%, approximately 10% higher than those of traditional deep learning models, while the recall rate is 0.927. In twelve fault diagnosis cases of Case Western Reserve University dataset under variable working conditions, the average accuracy obtained by the proposed model is 99.97%, approximately 10% higher than those of traditional models. The conditional distribution discrepancy between different domains reduces by using the pseudo-labels. The inconsistency problem of data distribution of source domain and target domain is properly addressed. The high-level features of samples from different scales can be aligned by the multi-scale feature learner. The generalization and robustness of the model largely increase. In conclusion, the proposed model has a high potential for the train bearing fault diagnosis under variable working conditions.