Aiming at the problem that traditional signal time-frequency analysis methods are not suitable for non-stationary signal

by using gearbox time domain vibration signals to build AR model

least squares method to calculate model parameters

and AIC formula to ascertain model order

status space model is also built for Kalman filter.Mathematical morphology fractal dimension method is used for calculating signal fractal dimension after filtering.This method is used for signal analysis of normal gears

tooth surface abrasion

gear tooth crack and tooth fracture.The analysis results of measured signal show that the method based on Kalman filter and mathematical morphology can recognize gear fault types effectively

and it offers a new feature extract method for gearbox fault diagnosis.