Operation Dynamics Analysis Of Current Collector For Medium-Low-Speed Maglev

As a new urban rail transit system,medium-low-speed maglev vehicles have the advantages of small turning radius,strong climbing ability,low vibration and noise,and low engineering cost.They are favored by many cities and show well development prospects.However,the engineering practice shows that the current system may become a restriction factor for further speed-up of medium and low speed maglev.The medium-low-speed maglev vehicles receive current by sliding contact between current collector and contact rail.Maintaining stable current collection is the basis of vehicle suspension,traction and braking.The quality of current collection will seriously affect the operation quality of vehicle.With the development of urban rail transit and the expansion of station spacing,the requirements for vehicle speed are gradually increasing,and the current collection stability will also be challenged.The maximum speed of medium-low-speed maglev vehicles in commercial operation is 100 km/h,which can realize stable current collection;however,the current collection quality of medium-low-speed maglev vehicles with design speed up to 160 km/h is still lack of corresponding research.This thesis takes the three suspension vehicles with a speed of 160 km/h,which is developed by the cooperation of Southwest Jiaotong University and CRRC DALIAN CO.,LTD.as the object to carry out dynamic analysis of the current receiving system.In order to study the current collection quality of the medium-low-speed maglev vehicles with the speed of 160 km/h,this thesis takes the current collector and the contact rail,which is the shoe rail system,as the research object,takes the current collection characteristics of the shoe rail system as the starting point,analyzes the running posture of the current collector,compares the modes of the current collector and the contact rail,and establishes the rigid flexible coupling shoe rail dynamic model considering the flexibility of the contact rail.In order to approach the engineering application,this thesis establishes a rigid flexible coupling shoe rail dynamic model with vehicle vibration by importing the vibration data of the installation position of the current collector of medium-low-speed maglev vehicles,and proves the correctness of the model through step-by-step verification.At the same time,taking the range of contact force,average value of contact force,standard deviation of contact force,qualified rate of contact force,off-line rate of slipper and vibration acceleration standard deviation of slipper as evaluation indexes,spring preload of current collector,the influence of shoe rail contact stiffness,slipper mass of current collector and spring stiffness of current collector on current collection quality is analyzed.The main conclusions are as follows:(1)The first rigid mode of the current collector is 0.48 Hz,and the first mode of the contact rail is 14.35 Hz.There is no resonance between the two modes during vehicle operation;(2)Under the different spring preload conditions,the range,average value,standard deviation,qualified rate of contact force and vibration acceleration standard deviation of slipper increase with the increase of spring preload and running speed,while the off-line rate decreases with the increase of spring preload.In order to ensure the quality of current collection,it is suggested that the spring preload should be close to 700 N;(3)Under the condition of step irregularity,the range of contact force,standard deviation of contact force,off-line rate and vibration acceleration standard deviation of slipper increase with the increase of contact stiffness and running speed,while the qualified rate of contact force decreases with the increase of contact stiffness and running speed.In order to ensure the quality of current collection,it is suggested that the contact stiffness should not be no more than 10 MN/m;(4)Under the different slipper mass conditions,the range of contact force,standard deviation of contact force and off-line rate increase with the increase of mass and running speed of slipper,while the vibration acceleration standard deviation of slipper increases with the increase of running speed and decreases with the increase of mass of slipper.When the running speed is lower than 140 km/h,the qualified rate of contact force increases with the increase of shoe mass and running speed;when the running speed is higher than 140 km/h,the qualified rate of contact force increases with the increase of running speed,and increases first and then decreases with the increase of shoe mass.In order to ensure the quality of current collection,it is suggested to select carbon slipper impregnated with metal;(5)Under the different spring stiffness conditions,the contact force range and off-line rate increase with the increase of running speed and spring stiffness,the contact force standard deviation and vibration acceleration standard deviation of slipper increase with the increase of running speed and decrease with the increase of spring stiffness,the contact force qualification rate increases with the increase of running speed,and increases first and then decreases with the increase of spring stiffness.In order to ensure the quality of current collection,t it is suggested that the spring stiffness should not be less than 20 kN/m.