Fault Diagnosis of Gear Pitting Based on Dynamic Strain Measurements from Fiber Bragg Grating Sensors

With the advance of drive-trains, it is more and more important to monitor the running state of the equipment and diagnose the faults at their early stages. The vibration methods are popular to be used to monitor the running state of the gearbox, however the complex transfer path usually degrade the SNR of the vibration measurements that causes the weak fault signal difficult to be recognized. To address this issue, the sensor is preferred to mount close to the gear teeth meshing position as near as possible. A fiber Bragg grating can be employed as the strain sensor with advantages of its small size and corrosion resistance, which is capable to work in a harsh environment Moreover, a number of fiber Bragg grating based measuring points can be made on one optical fiber with the wavelength division multiplexing array. In this work, the fiber Bragg gratings were studied to install along the base circle of a gear directly approaching to the meshing position, which demonstrates their potential to capture the characteristics of root strain during the meshing process. Therefore, this paper proposes a novel method for gear pitting fault diagnosis based on Fiber Bragg grating strain sensors to process the strain measurements. The algorithm employs a normalization and cross-correlation process to filter out the disturbance caused by load or speed fluctuations whilst improving the effectiveness of the fault detection based on strain measurements.