Research On Friction Vibration Characteristics Of Current Collector/Third Rail

The third rail current collector is the main current collection modes of urban rail transit vehicles which are widely used in urban rail transit system.When the vehicle is running,the collection shoe of the current collector is continuously contacted with the third rail to realize the stable current receiving.The friction between the collection shoe and the contact rail is a non-lubricated sliding friction.The friction between the contact interface changes with the contact state to induce the collection shoe to produce unstable flutter phenomenon,resulting in stick-slip motion,and the increased wear and tear of the collection shoe,seriously affecting the current-receiving quality.Therefore,it is important to explore the friction vibration characteristics of the interface between the collection shoe and the third rail,which is of great significance to improve the stability of the current collection system.In this paper,based on the study of the motion mechanism of the current collection system in the rail vehicle,the cause of the friction vibration between the contact surfaces of the current system is analyzed.A dynamic model of single degree of freedom friction vibration is established by the method of lumped parameter to reflect the lateral friction vibration of the current collector.The Stribeck friction model is used to describe the friction between the contact surfaces of the collection shoe and the third rail.The dynamic response of the model was simulated by MATLAB,and the dynamic response of the system under different system parameters was obtained.Then the friction model is replaced by the LuGre friction model,and the dynamic response of the system is further studied.The results of the dynamic analysis of the two friction models are consistent.Based on the above research work,the dynamic characteristics of the friction vibration phenomenon of the current collector under the variable normal contact pressure are analyzed according to the actual characteristics of the system.Finally,the ADAMS software was used to establish the dynamic model of the transverse and longitudinal two degrees of freedom friction vibration of the the current collection system,and the preliminary dynamic simulation was carried out.Compared with the experimental data,the model can reflect the real state of the system.In this paper,the theory of friction vibration is introduced to explain the instability of the interface between the contact surfaces of the system.And the corresponding measures to suppress the vibration of the system are put forward.The results show that the system is more stable by selecting the appropriate driving speed,increasing the rigidity and damping of the system,reducing the difference between the dynamic and static friction coefficient and maintaining the stability of the normal contact pressure.