Interpretable Sensor Importance-Based Multi-Sensor Integration for Condition Monitoring of Rotating Machinery

Accurate condition monitoring of rotating machinery requires integrating multi-sensor data to capture fault-related information distributed across sensing locations. While attention-based deep learning models can assess sensor importance, their lack of transparency limits industrial adoption. This study proposes an interpretable sensor importance-based multi-sensor integration framework combining a CNN-inspired kernel sharing strategy, a Transformer encoder for local and global feature extraction, and a channel attention mechanism for dynamic sensor weighting. Attention weight in Transformer encoder was analyzed in frequency domain to reveals spectral components influencing sensor importance evaluation. Validation on a pump testbed with various speeds conditions shows superior fault diagnosis accuracy, robustness to unseen conditions, and clear alignment between high-weight sensors and known fault frequencies, supporting trustworthy AI-driven condition monitoring in practice.