A staged deep multi-source domain adaptation framework based on loss dynamic adjustment for bearing fault diagnosis
摘要
Existing studies on multi-source domain deep transfer learning (DTL) methods inadequately leverage the distribution distance between multi-source and target domains. This limitation leads to incomplete cross-domain alignment and negative transfer problems in practical conditions. Therefore, a staged deep multi-source domain adaptation (SDMDA) framework based on loss dynamic adjustment is proposed. Primarily, the dilated temporal convolutional network (DTCN) common feature extractor and joint classifiers are proposed to achieve domain-invariant deep feature extraction and classification, respectively. Moreover, a loss dynamic adjustment mechanism (LDAM) is proposed, which uses Wasserstein distance between the predicted labels of each domain combination to dynamically adjust the difference alignment loss weights for the whole source domains during batch-wise training iterations. On this basis, a negative transfer inhibition mechanism (NTIM) is proposed to strengthen the alignment of target domain feature distribution in the subsequent phase of the training process. The experimental results on three datasets demonstrate excellent performance of the SDMDA framework.