Experimental Study On The Press Control System Of GMC-96_x Rail Grinding Train

With the development of the railway transportation system,especially the high-speed railway,mileage has reached 22 thousand kilometers,and the railway track maintenance technology has rapidly developed.Rail grinding plays a key role in improving wheel-rail relation,eliminating rail corrugation and rolling contact fatigue as the main method of the maintenance of rail surface quality.In the practice of rail grinding,it is found that there are some quality defects such as uneven grinding depth and uneven light band in some grinding sections.There are many factors that affect the quality of grinding,and pressure fluctuation is the most common reason.The rail grinding principle is constant-power grinding loaded by an hydraulic system.The control of grinding pressure is accomplished by an electro-hydraulic proportional pressure control system controlled by PID which uses a grinding motor current as negative feedback.If the load pressure has an abnormal fluctuation,the grinding motor power will be unstable,which would cause an uneven grinding depth and an abnormal light band on the rail surface.Due to the external excitation caused by track irregularity,it is relatively difficult to keep the pressure constant while loading.So it is necessary to study the actual rules of the load pressure fluctuation and the setting of PID parameters in order to improve the system response,reduce the pressure fluctuation as much as possible and achieve constant-power grinding.Thereby better grinding quality can be achieved.In order to study the fluctuation of grinding load pressure,a small hydraulic system is used to measure the pressure based on a virtual instrument constructed in Labview.Once the grinding and pressure data has been acquired the working process of the rail grinder can be detected,analyzed and saved with the system in real time.Furthermore,this paper studies the effects of PID parameters on the pressure fluctuation of the load control system.Based on analyzing the electro-hydraulic proportional pressure control system,a simulation model of the pressure control system installed in the rail grinder is built using the AMESim model.So that simulations of variable parameters of PID can be done and a group of PID parameters that has minimum load pressure fluctuation can be obtained.The practical application of research results applied in the pressure control system of the rail grinder is presented.The results obtained by the analysis of the pressure data that was acquired under various working conditions of the rail grinder show that the standard deviation of pressure decreased by 13.57% when using the PID parameters of the research results compared with using those of original rail grinder before.It significantly reduces the pressure fluctuation of the grinding system.The research results can provide an useful technical measure for improving the grinding accuracy of the rail grinder.