Research On Key Technologies For Rail Wear And Grinding

Rail grinding is recognized as the most effective way to relieve the rail wear and increase the service life of the rail.Grinding the rail regularly by rail grinding wagon could eliminate the track irregularity and railhead defects,repair the railhead profile to the best profile,slow the development of the rail surface defects,improve the rail surface smoothness,reduce the wheel/rail noise and increase the service life of the rail.The key technologies of the rail automatic grinding is studied in this paper.The main research contents and research results are as follows:(1)The "minimum normal clearance of wheel/rail" method is adopted to design the rail grinding profile.The analysis of the wheel/rail contact stress was done and the result shows the designed profile could reduce the contact tress obviously.On the basis of analyzing the working mechanism of grinding mode,this paper proposed a method to design the grinding mode.(2)The mechanical structure of the grinding device was designed and the grinding angle adjustment mechanism was analyzed in detail.The angle adjustment mechanism could adjust the angle from 67° inside of rail head to 45° outside.(3)A speed control system to stabilize the motor speed was designed based on the principle of vector controlling.(4)The Smith Controller was adopted to overcome the disturbance from the track irregularity and the vibration in the process of rail grinding and keep the stability of the grinding force.To improve the precision of the Smith Controller,the feedback loop of the Smith Controller was reformed using the load torque observer and the system online identification model based on wavelet neural network.The control effect was analyzed through Simulink,and the simulation result indicates that:Compared with PID control,the controller designed in this paper could achieve a fast tracking and response of the step input without overshoot and oscillation.And in the whole control process the current of the grinding motor,which reflects the grinding force,waves within a small scale.And it shows that the controller could restrain the external interference effectively.