An order analysis based second-order cyclic function technique for planetary gear fault detection

Planetary gearbox is a widely used transmission machine with complex and dynamic internal mechanical structures and it usually operates under non-stationary hostile operational conditions. The complex internal gears dynamic behaviors and the resultant vibrations make the fault diagnosis of planetary gears problematic. Effective diagnostic methods for planetary gear system are in demand. In this paper, an order analysis based second-order cyclic function method is proposed to extract the damage caused amplitude modulation under non-stationary operational conditions. The damage caused fault information is emphasized and being extracted and calculated as a distinctive indicator for fault diagnosis of planetary gear system. The experimental studies with 3 types of typical sun gear faults are demonstrated to validate the effectiveness of the proposed method.