Fault Identification of Low-Speed Hub Bearing of Crane Based on MBMD and BP Neural Network

Table 1

Time-frequency domain statistical parameters.

Frequency domain statistical parameters		Time-domain statistical parameters
Mean	Skewness	Spectral amplitude mean	Spectral root 4/2-moment ratio
Root mean square	Kurtosis	Spectral amplitude standard deviation	Spectral standard deviation frequency
Square root amplitude	Crest factor	Spectral amplitude skewness	Spectral frequency skewness
Mean amplitude	Clearance factor	Spectral amplitude kurtosis	Spectral frequency kurtosis
Maximum peak	Shape factor	Spectral gravity frequency
Standard deviation	Crest factor	Spectral root mean square frequency

Note. is the primary signal, and N is the number of data points. is the amplitude of the original signal spectrum, and M is the number of spectral lines. is the amplitude of the frequency of the kth spectral line.