Root Crack Identification of Sun Gear in Planetary Gear System Combining Fault Dynamics with VMD Algorithm

Table 6

Error between the simulated VMD IMF central frequency and theoretical value for 3^# crack.

IMF	VMD frequency (Hz)	Theoretical frequency (Hz)	Corresponding feature	Error (%)
IMF1	390.8	398.2	fm−11/4fsg	1.86
IMF2	1182	1194.8	2fm−5fsg	1.07
IMF3	1954	1944.6	3fm−1/4fsg	0.48
IMF4	2735	2741.2	4fm + 5/4fsg	0.23
IMF5	3457	3467.8	4fm + 9fsg	0.31
IMF6	4439	4427.9	7fm−7/4fsg	0.25