Machinery fault diagnosis using multi-scale feature focused network and adaptive cost-sensitive loss towards imbalanced dataset

Abstract The current deep learning based machinery fault diagnosis models still face challenges in effectively capturing rich multi-scale feature information and dynamically compensating training loss when dealing with imbalanced dataset. This paper presents a novel approach for machinery fault diagnosis using multi-scale feature focused network and adaptive cost-sensitive loss. Firstly, a multi-scale feature focused network is constructed with improved multi-scale CNN and point-wise attention mechanism module, in which the former can synthetically fuse the features at different scales to expand the coverage of the equivalent receptive field, and the latter can further refine fine-grained features and filter out irrelevant feature interference. Then, an adaptive cost-sensitive loss function is designed to adjust the cost matrix in the training process, dynamically assigning more loss weights for small samples that are difficult to distinguish. The experimental results of planetary gearbox fault diagnosis demonstrate that the proposed approach exhibits superior diagnostic performance compared to other existing methods.