Understanding theories and methods on fault diagnosis for multi-fault detection of planetary gears

Planetary gears have been widely used in transmission systems of helicopters, wind turbines and mine machineries, etc., due to their advantages on large ratio of transmission, high efficiency, compact structure. However, it is very difficult to detect faults of planetary gears, especially when multi-fault happens because of structure complexity. Prognostic and Health Management (PHM) is recognized as an emerging subject in system reliability engineering, in order to identify system failure and guarantee system operational safety. This paper conducted a comprehensive literature survey on new theories and methods of planetary gear fault diagnosis with multi-fault. Topics about multi-fault detection for planetary gears techniques are summarized in two aspects: dynamics modeling of planetary gears and signal processing techniques.