A Novel Diagnostic Scheme for Gear Pitting Fault Using Fiber Bragg Grating Based Strain Sensors

The performance of gearbox vibration monitoring techniques may degrade due to the signal distortion and attenuation which is usually caused by the complicated transmission path. The fiber Bragg grating sensing technique has attracting characteristics such as the small size, multiple measurement points on one fiber and resistance to oil corrosion. Therefore, this paper proposes a new approach for online monitoring of gearboxes based on fiber Bragg grating based strain sensors, in which the fiber Bragg grating sensors can be mounted closely to the meshing position of gear teeth. In this study, the working principle of the fiber Bragg grating and the configuration of the test rig is firstly presented. Then, the tooth root dynamic strain signals measured by fiber Bragg gratings under the healthy and gear pitting conditions were presented and compared with the finite element simulations. The comparison between the measured and simulated signals agrees well, which validates the feasibility of the employment of fiber Bragg gratings for the online monitoring of gearboxes. Furthermore, a novel diagnostic algorithm based on dynamic time warping is proposed to process the measured signals using fiber Bragg grating based strain sensors. The results show the proposed algorithm is able to diagnose the healthy and gear pitting conditions without the need of the pre-measured baselines.