A Hybrid CNN-LSTM method combined with EMD-HHT feature extraction for tool wear monitoring
摘要
Accurate tool wear monitoring is pivotal for ensuring machining precision in intelligent manufacturing systems. To overcome the limitations of traditional single-sensor approaches in exploiting multi-source heterogeneous signals, this study proposes a dual-channel CNN-LSTM framework integrating time-frequency and temporal feature fusion. EMD-HHT was used to generate intrinsic mode functions (IMFs), from which Hilbert spectral analysis was performed to construct 2D time-frequency representations (TFRs) encapsulating instantaneous amplitude-frequency characteristics. These TFRs were processed through a Convolutional Neural Network (CNN) combining residual blocks and multi-head attention mechanisms to extract hierarchical spatial features. In parallel, an attention-enhanced Long Short-Term Memory (LSTM) network was used to capture long-range temporal dependencies from denoised signal sequences. The features extracted from both channels were concatenated and fed into a fully connected layer to perform the final classification task. Experimental validation on a five-axis machining dataset, using a Leave-One-Cutter-Out Cross-Validation (LOCO-CV) strategy, shows that the proposed method achieves an average accuracy of 94.28%, outperforming conventional methods in generalization capability.