A new vibration signal model of two-stage planetary one-stage parallel gear box and automatic fault diagnosis of parallel stage

Abstract Propose a typical fault automatic diagnostic method based on a new phenomenological model of two-stage planetary and parallel gearbox vibration signals, focusing on the impact of coupled modulation phenomena on manual diagnosis. Analysis reveals distinct modulation patterns around characteristic orders during faults in high and low-speed shafts. Building upon existing models for two-stage gearbox faults, the new model incorporates modulation patterns in a third parallel stage. The objective function, based on angular domain and residual envelope of vibration data, optimizes model parameters using parameter identification methods to fully capture coupled modulation characteristics. Using experimental spectral features and sideband amplitudes, fault indices are constructed to diagnose parallel stage faults. Similarity analysis between identified model features and fault indices enables automatic diagnosis of typical faults. Simulation and field tests demonstrate accurate detection of fault characteristics and high precision in diagnosis, validated by correlation coefficient analysis. Utilizing fault indices enables relatively precise automatic diagnostic of typical faults, showing promising practical engineering application in wind turbine gearbox condition monitoring.