A Study On Fault Diagnose Of Gear Pairs With Cracked Tooth Based On Kalman Filter

Gear transmission is the most important and widely used mechanical transmission.Gear drive failure is a common failure of the gearbox.After the gear fault occurs,it will directly affect the safe and reliable operation of the equipment,reduce the production efficiency or cause serious consequences such as casualties.In order to prevent catastrophic accidents caused by sudden gear failures,it is necessary to study the fault diagnosis method for gears.However,due to the complex vibration mechanism and characteristics of the gear transmission system,it is difficult to achieve effective and accurate fault diagnosis.Therefore,the study of gear fault diagnosis methods is important for theoretical and engineering.The contents of the thesis are as follows:(1)Introduce the calculation method of time-varying meshing stiffness of gear teeth,analyze the different forms of tooth root crack,establish the tooth contact FE model with different gear-root cracks in Abaqus,calculate the time-varying meshing stiffness,and obtain the tooth root.The influence of crack on time-varying meshing stiffness and the stiffness variation characteristics of crack-containing gears are analyzed.(2)Analyze the internal excitation of the cracked gear pair(stiffness,error and impact),and establish the system dynamics model of the cracked gear pair by analytical method,and calculate its dynamic response in Matlab,and analyze the change of time-varying meshing stiffness to the gear.The influence law of the secondary dynamic response is studied to study the dynamic characteristics of the cracked gear.(3)Introduce the model-based fault diagnosis theory,and establish the fault system model in the state space;derive the residual signal calculation method based on Kalman filter;use the generalized likelihood ratio test to solve the fault threshold and realize the fault feature extraction.(4)Carry out the fault simulation experiment with cracked gears to obtain the actual measured vibration signal;based on the Kalman filter fault diagnosis method,analyze the experimental data,calculate the residual signal with the vibration data of the gear as the characteristic,and determine the fault threshold of the different sizes corresponding to the crack realizes real-time fault diagnosis and alarm for the cracked gear pair.