Structure-preserving constrained smoothing model for partial cross-domain fault diagnosis under time-varying conditions.

Fault diagnosis based on partial domain adaptation (PDA) has gained extensive attention, since it allows mismatched label sets between source and target domains and is thus more consistent with practical engineering applications. However, existing methods exhibit limited diagnostic performance under time-varying speed conditions. In this study, we propose a Structure-Preserving Constrained Smoothing Model (SPCSM) for partial cross-domain fault diagnosis, which is validated under time-varying speed conditions. By integrating the intrinsic geometric structure of the target domain with the category structure derived from the source domain, the model effectively enhances its smoothness, thereby mitigating the adverse effects of speed fluctuations on diagnostic performance. Experimental results demonstrate that the proposed SPCSM achieves an average accuracy of 98.06% on single-device tasks and 89.50% on cross-device tasks, outperforming several domain adaptation models.