Semi-supervised ensemble fault diagnosis method based on adversarial decoupled auto-encoder with extremely limited labels.

• A semi-supervised ensemble framework termed ADAE-LFDM is proposed for fault diagnosis in extremely limited labels scenarios. • An adversarial decoupled auto-encoder network for fault feature decoupling is designed to enhance the representation capabilities of fault feature. • The low-dimensional feature distance metric is designed to enable accurate recognition of new data, which can mitigate the disadvantage imposed by extremely limited labels. • Experiments in extremely limited labels scenarios are designed on bearing and gear datasets to verify the superiority of the proposed methods. Intelligent fault diagnosis can enhance the reliability of mechanical equipment. However, only a few labels are available in a large amount of fault data due to high labeling costs in practical engineering. The fault recognition capability of existing semi-supervised diagnosis methods is severely insufficient with limited labels, especially with extremely limited labels that only a single labeled sample available per fault type. To address this issue, a novel semi-supervised ensemble fault diagnosis framework termed ADAE-LFDM is proposed based on adversarial decoupled auto-encoder (ADAE) and low-dimensional feature distance metric (LFDM). Firstly, the locally selective combination in parallel outlier ensembles (LSCP) method is introduced to efficiently separate normal and fault samples. Subsequently, an ADAE with branching structure and latent space feature regularization strategy is proposed to decouple and capture the fault feature. Finally, a LFDM strategy that contains feature dimensionality reduction, and centroid-based metric is performed to achieve high-accuracy fault diagnosis. Experimental results based on two rotating machinery datasets have demonstrated that the proposed method achieves a diagnostic accuracy of over 97 % when there is only a single labeled sample available per fault type, and an average diagnostic accuracy of 85 % under cross-operating condition, showing the superiority compared to other methods. [ABSTRACT FROM AUTHOR]