Fault Diagnosis of Planetary Gearboxes with Ring Gear Strain Signals Measured by Fiber Bragg Gratings

Fault diagnosis of planetary gearboxes using acceleration signals is facing difficulties at present. In order to solve the problem, the strain signals of ring gear are adopted in this paper. First, the features of two typical faults are revealed in the outer surface strain and tooth root strain of ring gear respectively. Then, a fiber Bragg grating wavelength demodulation system with a high resolution is established to measure the strain of the ring gear. Finally, the fault diagnosis experiments are carried out. After signal processing, the feature frequency of the run-out error appears in the frequency spectrum of the surface strain signal, and the second derivative of the tooth root strain signal near the crack tooth gets larger amplitude, which shows the effectiveness of the fault diagnosis method based on strain signals.