Research On Friction Characteristics And Friction Force Modeling Of Sliding Electrical Contact Under Fluctuation Load

The pantograph-catenary system is an important part of the electrified rail transit traction power supply system.The friction and wear performance with current-carrying of the pantograph-catenary system directly affects the current collection quality of the electric locomotive,the service life of the pantograph slider,and the maintenance cost of the catenary.Current-carrying friction and wear is the main feature of sliding electrical contact,and friction force is an important factor that causes contact wear.Then,with the great increase of the train running speed and carrying capacity,aggravation of the dynamic contact pressure load changes between pantograph-catenary,the pantograph-catenary relationship problem become more and more prominent,and the fluctuation phenomenon increasingly and significantly affect its friction and wear performance.Aiming at this practical problem,this paper researches the sliding electrical contact friction characteristics and friction force modeling under fluctuation load.The pin-on-disc high-speed current-carrying friction and wear experimental machine,with copper-impregnated carbon grinding pin and pure copper disc as friction pair,through a large number of experiments research,is used to obtain friction characteristics related to pressure load,sliding speed,current density,pressure load fluctuation range and fluctuation frequency,and the theoretical analysis is carried out.The results show that:the sliding electrical contact friction force of pantograph-catenary increases with the increase of the pressure load,and the increase of the friction force gradually becomes slower;the friction force decreases with the increase of the current density;the friction force increases with the increase of the sliding speed;the friction force increases with the increase of the pressure load fluctuation range,and the fluctuation range of the friction force also increases;when the pressure load fluctuation frequency is small and not changing significantly.the friction force slight increases with the increase of the pressure load fluctuation frequency.On the basis,under the pantograph-catenary system,the friction force regression model is established by using support vector machine,with pressure load,current density,sliding speed,pressure load fluctuation range and fluctuation frequency as the independent variables,friction force as the dependent variable.And genetic algorithm is used to optimize the parameters.The validity of the model is verified by the experimental data,which provides a reference for further research on the friction force prediction and the friction performance of the pantograph-catenary sliding electrical contact.