CNN-Multi-Head Attention Framework for Gearbox Incremental Fault Diagnosis Under Non-Stationary Conditions

Deep learning-based gearbox fault diagnosis approaches have demonstrated exceptional performance in achieving accurate fault identification across diverse industrial applications. Nonetheless, machines frequently operate under conditions characterized by time-varying speeds or loads, known as non-stationary working conditions. When a series of different non-stationary conditions tasks are sequentially input into the model for training, an issue arises where the model tends to forget previous tasks, a phenomenon referred to as "catastrophic forgetting". To address the challenge posed by task increments within non-stationary conditions, this paper proposes an incremental learning-based multi-task fault diagnosis framework under non-stationary conditions. This methodology enhances the model's diagnostic capabilities under non-stationary conditions by amalgamating convolutional neural network (CNN) with multi-head self-attention mechanisms. It employs exemplar replay and hybrid cross-head knowledge distillation techniques to preserve the model's understanding of prior tasks, thereby facilitating the incremental learning of multiple tasks. The efficacy of this proposed framework is substantiated through its application on the MCC5-THU fault diagnosis datasets of gearbox under time-varying speed working conditions. Experimental results demonstrate that this approach significantly mitigates the "catastrophic forgetting" effect, thereby offering a robust solution for multi-tasks increment fault diagnosis of gearbox operating under non-stationary conditions.