Scattering moment matching-based interpretable domain adaptation for transfer diagnostic tasks

Abstract

One significant fact familiar to the signal processing-based diagnostic community but generally ignored by the transfer learning-based diagnostic community is that the cyclostationarity of the monitored signal conveys the actual diagnostic information. Popular network architectures, e.g., ResNet, and domain discrepancy metrics, e.g., maximum mean discrepancy, in current transfer diagnostic research are generally borrowed from the transfer learning community yet do not explicitly consider machine fault physics. As Jérôme Antoni points out, signal processing and machine learning methods are not mutually exclusive but should complement each other. The current article aims to develop an interpretable domain adaptation method for transfer diagnostic tasks by simultaneously exploiting the ideas of cyclostationary signal processing and domain adaptation techniques. By taking NTScatNet as the network backbone and scattering moment distance as the domain discrepancy metric, the proposed scattering moment matching-based domain adaptation method is more interpretable and matches fault physics better than conventional deep transfer learning methods. Besides, the proposed method does not require target domain data during the training phase, thus relaxing the assumption of standard domain adaptation. The effectiveness and superiority of the proposed domain adaptation method were verified on four transfer diagnostic case studies, i.e., transfer diagnostic across bearing specifications, transfer diagnostic across escalator roller specifications, transfer diagnostic across transducers on bearing datasets, and transfer diagnostic across transducers on the gearbox datasets.