Normalization-Guided and Gradient-Weighted Unsupervised Domain Adaptation Network for Transfer Diagnosis of Rolling Bearing Faults Under Class Imbalance

Transfer learning has garnered significant interest in the field of bearing fault diagnosis under varying operational conditions due to its robust generalization capabilities. However, real-world diagnostic scenarios frequently encounter data imbalances, which complicates the learning of the classif...

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Main Authors: Hao Luo, Xinyue Wang, Li Zhang
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Actuators
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Online Access:https://www.mdpi.com/2076-0825/14/1/39
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author Hao Luo
Xinyue Wang
Li Zhang
author_facet Hao Luo
Xinyue Wang
Li Zhang
author_sort Hao Luo
collection DOAJ
description Transfer learning has garnered significant interest in the field of bearing fault diagnosis under varying operational conditions due to its robust generalization capabilities. However, real-world diagnostic scenarios frequently encounter data imbalances, which complicates the learning of the classification boundary for the minority class within the diagnostic model. To address this challenge, we propose a normalization-guided and gradient-weighted unsupervised domain adaptation network (NG-UDAN) for intelligent bearing fault diagnosis, aimed at tackling inter-domain feature shifts and intra-domain category imbalances. Firstly, the proposed network integrates a residual feature extractor with the Domain Normalization (DN) module to enhance domain-invariant feature extraction. Subsequently, the Local Maximum Mean Discrepancy (LMMD) loss is utilized to minimize the conditional distributional differences between the source and target domains. Finally, the Gradient-Weighted Focal Loss (GWFL) is specifically designed to address the issue of class imbalance. Experiments conducted across three imbalanced scenarios using the Case Western Reserve University (CWRU) and Paderborn University (PU) datasets demonstrate that NG-UDAN is effective in both single-source and mixed-source domain adaptation. Furthermore, comparisons with alternative methods validate the superiority of this approach in managing class imbalances under varying working conditions.
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spelling doaj-art-92b1dcaca4ff461daaba2b459809b0ff2025-01-24T13:15:16ZengMDPI AGActuators2076-08252025-01-011413910.3390/act14010039Normalization-Guided and Gradient-Weighted Unsupervised Domain Adaptation Network for Transfer Diagnosis of Rolling Bearing Faults Under Class ImbalanceHao Luo0Xinyue Wang1Li Zhang2College of Information, Liaoning University, Shenyang 110036, ChinaCollege of Information, Liaoning University, Shenyang 110036, ChinaCollege of Information, Liaoning University, Shenyang 110036, ChinaTransfer learning has garnered significant interest in the field of bearing fault diagnosis under varying operational conditions due to its robust generalization capabilities. However, real-world diagnostic scenarios frequently encounter data imbalances, which complicates the learning of the classification boundary for the minority class within the diagnostic model. To address this challenge, we propose a normalization-guided and gradient-weighted unsupervised domain adaptation network (NG-UDAN) for intelligent bearing fault diagnosis, aimed at tackling inter-domain feature shifts and intra-domain category imbalances. Firstly, the proposed network integrates a residual feature extractor with the Domain Normalization (DN) module to enhance domain-invariant feature extraction. Subsequently, the Local Maximum Mean Discrepancy (LMMD) loss is utilized to minimize the conditional distributional differences between the source and target domains. Finally, the Gradient-Weighted Focal Loss (GWFL) is specifically designed to address the issue of class imbalance. Experiments conducted across three imbalanced scenarios using the Case Western Reserve University (CWRU) and Paderborn University (PU) datasets demonstrate that NG-UDAN is effective in both single-source and mixed-source domain adaptation. Furthermore, comparisons with alternative methods validate the superiority of this approach in managing class imbalances under varying working conditions.https://www.mdpi.com/2076-0825/14/1/39fault diagnosisunsupervised domain adaptationclass imbalancerolling bearing
spellingShingle Hao Luo
Xinyue Wang
Li Zhang
Normalization-Guided and Gradient-Weighted Unsupervised Domain Adaptation Network for Transfer Diagnosis of Rolling Bearing Faults Under Class Imbalance
Actuators
fault diagnosis
unsupervised domain adaptation
class imbalance
rolling bearing
title Normalization-Guided and Gradient-Weighted Unsupervised Domain Adaptation Network for Transfer Diagnosis of Rolling Bearing Faults Under Class Imbalance
title_full Normalization-Guided and Gradient-Weighted Unsupervised Domain Adaptation Network for Transfer Diagnosis of Rolling Bearing Faults Under Class Imbalance
title_fullStr Normalization-Guided and Gradient-Weighted Unsupervised Domain Adaptation Network for Transfer Diagnosis of Rolling Bearing Faults Under Class Imbalance
title_full_unstemmed Normalization-Guided and Gradient-Weighted Unsupervised Domain Adaptation Network for Transfer Diagnosis of Rolling Bearing Faults Under Class Imbalance
title_short Normalization-Guided and Gradient-Weighted Unsupervised Domain Adaptation Network for Transfer Diagnosis of Rolling Bearing Faults Under Class Imbalance
title_sort normalization guided and gradient weighted unsupervised domain adaptation network for transfer diagnosis of rolling bearing faults under class imbalance
topic fault diagnosis
unsupervised domain adaptation
class imbalance
rolling bearing
url https://www.mdpi.com/2076-0825/14/1/39
work_keys_str_mv AT haoluo normalizationguidedandgradientweightedunsuperviseddomainadaptationnetworkfortransferdiagnosisofrollingbearingfaultsunderclassimbalance
AT xinyuewang normalizationguidedandgradientweightedunsuperviseddomainadaptationnetworkfortransferdiagnosisofrollingbearingfaultsunderclassimbalance
AT lizhang normalizationguidedandgradientweightedunsuperviseddomainadaptationnetworkfortransferdiagnosisofrollingbearingfaultsunderclassimbalance