A novel bearing fault diagnosis method under small samples using time-frequency multi-scale convolution layer and hybrid attention mechanism module

Deep neural networks for bearing fault diagnosis have become the focus of research in recent years with its excellent feature extraction capability. However, the problem of diagnosis under small samples still needs to be solved in industrial applications, because bearings rarely work in the fault state in practice, resulting in the scarcity of fault data. To solve this problem, this paper proposes a new diagnosis model, a time-frequency multi-scale attention network, which structure allows the original signal and its transformed spectrum to be used as the input in parallel. A multi-scale convolutional layer is also designed to extract information from the signal at different scales to enhance the feature extraction capability of the network. In addition, a hybrid attention mechanism is added to integrate the redundant features and realize the complementarity between features. The experimental results of seven bearing diagnosis cases from two bearings show that the proposed method can achieve high diagnostic accuracy under small samples, which proves the superiority of the proposed method. The time domain signal and frequency domain signal were respectively used as input to train the model. By comparing the accuracy with the time-frequency combined signal as input, the superiority of the time-frequency domain signal as input is proved.