Research On Gearbox Fault Diagnosis Of Urban Rail Vehicle Based On SIMPACK

Urban rail vehicle as an important public transportation, its operational safety of is very essential for the safety of people’s lives and property. The gearbox is not only a key component of urban rail vehicle, but also a component which easy to cause faults, and its running state will directly impact the operating condition of urban rail vehicle. So researching on gearbox fault diagnosis of urban rail vehicle has great significance. It could achieve the fundamental change from corrective maintenance, regular maintenance to condition based maintenance (maintenance based on state) for the gearbox. The current researches on the gearbox fault diagnosis are based on experiment platform, but this method has some disadvantages, for example, large investment, narrow scope, the simulation form of gearbox fault and the fault simulation degree are severely limited etc. To compensate for the lacking of current research methods, this thesis provides a new simulation method which based on the multi-body dynamics software-SIMPACK to research the gearbox fault. This method can be applied to simulate the fault of gearbox which used in different equipments. And the fault form and fault degree that to be simulated are variously. Namely, it can be used to analysis different kinds of gearbox faults according to the actual needs.This thesis takes the typical gearbox faults of urban rail train as the analysis model. Using the time, frequency domain analysis and wavelet packet analysis method to study the simulation signals. The result can proof the feasibility and reliability of the method which based on SIMPACK to do analysis for the gearbox fault. Simultaneously, this thesis also research methods that how to get the time, frequency domain features of various failure signals. Finally, the different types of faults are isolated using SVM algorithm. This has important reference value to achieve rail gearbox condition monitoring and fault diagnosis.As follows is idiographic research of this thesis.(1) Introduce the main failure mode of the various components of gearbox system and the main type of gearbox system faults. This part also focuses on the analysis of the vibration mechanism of gear and gear vibration frequency.(2) Simulate the gearbox system of urban rail vehicle with SIMPACK, and verify the feasibility and reliability of the simulation model. Build simulation model for several typically gearbox system faults base on the normal model, namely uniform wear of gear, axle misalignment and axle slightly bent. Among them, for the particularity of axle slightly bent, this part highlights how to build elastomer model.(3) Represent the theoretical knowledge of time and frequency domain analysis method. And apply this method to gearbox fault analysis, analysing and handling the various fault signals based on simulation. Conclude the time and frequency domain features of each failure mode, and the results have proved the feasibility and affectivity of this method.(4) Describe the theoretical knowledge of wavelet packet, and research its application in gearbox system fault diagnosis. Analyze and compare the normal and fault signal, and then get the characteristic of fault signal(5) Systematically introduce the theoretical basis of SVM algorithm and its application in fault isolation, and apply this method to the fault isolation of gear box. The analysis result shows the feasibility of this algorithm in the fault isolation of gearbox, and in this part time domain, frequency domain and dimensionless characteristic values are taken as input.