Fault diagnosis of tooth surface spalling of planetary gearbox based on GWO-TVF-EMD method

In order to overcome the shortcomings of the time varying filter for empirical mode decomposition （TVF-EMD） method，the sample entropy was used as the fitness function.The gray wolf optimization （GWO） algorithm was used to optimize the bandwidth threshold and B-spline order core parameters，and the optimal combination solution was obtained to decompose the vibration signals of different fault impact tests.The selection process of intrinsic mode function （IMF） components was optimized，and multiple weighted indexes were used to calculate all the IMF components，and finally the optimal IMF component was selected.Then，the spalling fault features of planetary gear were extracted by envelope spectrum analysis.In the planetary gear box fault test，the root mean square method was used to identify the spalling fault initially，and the optimal IMF component of each spalling fault signal was obtained by GWO-TVF-EMD，and the envelope spectrum analysis was used to judge the fault frequency of the planetary gear clearly.The method can extract the detailed features of three different degrees of tooth surface spalling faults，and the relative error between the theoretical value and the actual value was 1.68%.