Wear Identification of Vibration Drilling Bit Based on Improved LMD and BP Neural Network

Table 3

Five-Layer wavelet decomposition frequency band of axial drilling force signal.

Serial number	D1	D2	D3	D4	D5	A5
Frequency band (Hz)	500∼250	250∼125	125∼62.5	62.5∼31.25	31.25∼15.625	15.625∼0