Application of wavelet dynamic joint adaptive network guided by pseudo-label alignment mechanism in gearbox fault diagnosis

In practical scenarios, gearbox fault diagnosis faces the challenge of extremely scarce labeled data. Additionally, variations in operating conditions and differences in sensor installations exacerbate data distribution shifts, significantly increasing the difficulty of fault diagnosis. To address the above issues, this paper proposes a Wavelet Dynamic Joint Self-Adaptive Network guided by a Pseudo-Label Alignment Mechanism (WDJSN-DFL). First, the Wavelet-Efficient Convolution Module (WECM) is designed based on wavelet convolution and efficient attention mechanisms. This module is used to construct a multi-wavelet convolution feature extractor to extract critical fault features at multiple levels. Secondly, to improve the classifier's discriminability in the target domain, a transitional clustering-guided pseudo-label alignment mechanism (DFL) is developed. This mechanism can capture fuzzy classification samples and improve the pseudo-label quality of the target domain. Finally, a dynamic joint adaptive algorithm (DJSN) is proposed, which is composed of Joint Maximum Mean Square Discrepancy (JMSD) and Joint Maximum Mean Discrepancy (JMMD). The algorithm can adaptively adjust according to the dynamic balance factor to minimize the domain distribution discrepancy. Experiments on two different gearbox datasets show that WDJSN-DFL performs better in diagnostic scenarios under varying load conditions and different sensor installation setups, validating the proposed method's effectiveness and superiority.