Gearbox Degradation State Recognition For Monorail Trains Based On Fault Injection

Monorail train is an effective way to solve urban traffic jams,and it is also one of the transportation tools with rapid development at present.Therefore,it becomes very important to improve the reliability and stability of monorail train transmission system.Gear box is the core component of the transmission system of monorail train.Under the influence of frequent start and stop of train and high load condition,gear degradation is easy to occur,which leads to more serious faults,causing huge economic losses to urban rail transit.Therefore,condition monitoring and degradation identification of monorail gear boxes are of great significance for improving the reliability of train transmission system,avoiding serious faults and reducing maintenance costs.In this paper,the gearbox dynamics model of the straddle monorail train was established,and the vibration response characteristics and degradation state recognition were studied and analyzed based on the degradation model data.The main research contents are:(1)Model construction and vibration mechanism analysis of monorail gear box.According to the gear pair parameters of monorail gear box,the assembly model and degradation model of monorail gear box are constructed in PROE.The time-varying meshing stiffness of the gears was obtained through the multi-body dynamics simulation calculation,and the rigid-flexible coupling model of the monorail gear box containing the flexible box was established by Hyper Mesh software.The dynamic response characteristics of the gear box were analyzed,and the vibration characteristics of the gear box with different degradation states and different gear pair degradation were studied.The results show that the established rigid-flexible coupling model of monorail gear box can fit the kinematic analysis results,and the characteristics of different degradation states of gear box can be obviously extracted from the vibration response of the rigid-flexible coupling dynamic model.The results show that: in the time domain,gear degradation directly leads to the overall vibration intensification,and in the frequency domain presents different vibration characteristics.(2)Extraction and analysis of monorail gear box degradation features.In the process of monorail gear box degradation,the overall vibration response of the box changes little,and the degradation characteristics are easy to be covered by noise and external environment interference,which makes it difficult to extract and analyze the degradation characteristics of monorail gear box.Based on the analysis of degradation failure forms,dynamic models of various degradation states were established in this paper to study the vibration response of monorail gear box under various degradation states.Meanwhile,combined with the performance degradation data of gear box,the time-domain and frequency-domain characteristics of monorail gear box under degradation conditions were analyzed,and detrending multifractal method was introduced to more comprehensively characterize the degradation characteristics of gear box.(3)Identification of monorail gear box degradation state combined with injection fault.Compared with normal working conditions,the initial degradation characteristics of monorail gear box have little difference in time-frequency domain characteristics,and the fault samples are rare,leading to poor model training effect.In order to identify the degenerate states of monorail gear boxes accurately,this paper introduces SSA-XGBoost classification algorithm,and designs a gearbox degradation state recognition model based on fault injection.Through the simulation data of the degradation model,the originally limited gearbox degradation feature data set was enriched.The SSA-XGBoost classification model was trained based on the degraded sensitive feature set,and the gearbox degradation state recognition combined with data-driven and model-driven was realized,which provided a certain reference for monorail gearbox condition monitoring and fault diagnosis.At last,the main research work of this paper is summarized,and the research of monorail gear box degradation state recognition technology is prospeced.