A novel adaptive gramian angle field based intelligent fault diagnosis for motor rolling bearings

The Gramian Angle Field (GAF) can encode one-dimensional vibration signals into two-dimensional feature maps containing time correlation information. However, the feature representation ability of traditional GAF-encoded images is limited, making it challenging to further improve fault diagnosis accuracy. To address these issues, an AGAF-CNN intelligent fault diagnosis method is proposed in this paper. In addition to traditional GAF encoding, an adaptive adjustment parameter is introduced that automatically determines its value based on the dynamic distribution characteristics of the input data. This ensures that the resulting feature map after two-dimensional encoding contains optimal fault discriminant features. By leveraging CNN's capability to process image data, the proposed method extracts deep-level feature representations from the vibration signal feature map and performs accurate diagnosis. The approach is validated using a rolling bearing dataset from Case Western Reserve University in the United States, and superior diagnostic accuracy is demonstrated compared to other vibration signal coding methods combined with CNN-based fault diagnosis methods. The theoretical and practical advantages of AGAF feature coding are explained comprehensively.