Controlled Generation of Unseen Faults for Partial and Open-Partial Domain Adaptation
This addresses domain adaptation challenges in safety-critical systems like fault diagnostics, where only healthy data is shared between domains, but it is incremental as it builds on existing GAN-based methods.
The paper tackles the problem of domain adaptation in fault diagnostics when fault classes differ between training and testing domains, proposing a framework using a Wasserstein GAN to generate controlled synthetic fault data for unseen faults. The method achieved superior results in partial and open-partial domain adaptation tasks on bearing fault case studies, particularly with large domain gaps.
New operating conditions can result in a significant performance drop of fault diagnostics models due to the domain shift between the training and the testing data distributions. While several domain adaptation approaches have been proposed to overcome such domain shifts, their application is limited if the fault classes represented in the two domains are not the same. To enable a better transferability of the trained models between two different domains, particularly in setups where only the healthy data class is shared between the two domains, we propose a new framework for Partial and Open-Partial domain adaptation based on generating distinct fault signatures with a Wasserstein GAN. The main contribution of the proposed framework is the controlled synthetic fault data generation with two main distinct characteristics. Firstly, the proposed methodology enables to generate unobserved fault types in the target domain by having only access to the healthy samples in the target domain and faulty samples in the source domain. Secondly, the fault generation can be controlled to precisely generate distinct fault types and fault severity levels. The proposed method is especially suited in extreme domain adaption settings that are particularly relevant in the context of complex and safety-critical systems, where only one class is shared between the two domains. We evaluate the proposed framework on Partial as well as Open-Partial domain adaptation tasks on two bearing fault diagnostics case studies. Our experiments conducted in different label space settings showcase the versatility of the proposed framework. The proposed methodology provided superior results compared to other methods given large domain gaps.