Passive wireless multi-parameter LC sensing system for in situ health monitoring of bearings

The health condition of bearings is crucial for the safe operation of equipment. In situ, multi-parameter monitoring of the rotating components of bearings facilitates accurate assessment and diagnosis of bearing health. Based on the previous research on LC (Inductor-Capacitor) strain sensor for bearings, a passive wireless multiparameter LC sensor suitable for in situ monitoring of bearings is proposed. The LC sensor uses dual resonance frequencies together with one quality factor to simultaneously monitor three parameters of bearing. Theoretical derivation and simulation analysis indicate that, due to the adoption of a symmetrical circuit structure, the two resonant frequencies of the LC sensor are independent and do not interfere with each other. Furthermore, the asymmetric analysis shows that under significant parameter asymmetry, the two resonant frequencies still maintain excellent independence. According to the installation position of the bearing, the sensor coil and the sensor circuit are designed to be conformal to the bearing. The acceleration, strain and temperature response curves of the LC sensor are measured by installing it on a circular steel disc that simulates the environment of a bearing. Finally, the LC sensor is successfully demonstrated on a bearing test platform.