Research On The Dynamic Response And Control Of Movable Clamp On Spot Rail Flash Welder Based On MATLAB

With the rapid development of Chinese economy,the railway has stepped into the new era of the comprehensive promotion of jointless track.Flash welding is the preferred way of rail welding on jointless track.The heating of flash welding is mainly achieved through the resistance heat of a short circuited liquid bridge,so the liquid bridge existing time affects the heating and end surface's state of the rail.However,the existence time of the liquid bridge is influenced by the dynamic performance of the movable clamp of welder.Due to the welding process test of rail is impossible to use on-site long rail,and the field working conditions are varied,therefore,the welding process obtained by short rail debugging is applied to rail welding on the spot,which has an influence on the quality of rail welded joints.But how to affect the welding quality and the extent of its impact have not been reported.Therefore,it is of great practical application value to study the influence of field conditions on the quality of welded joints.Aiming at the specific field construction condition of rail flash butt welding,based on the widely used UN5-150 ZB welder's control system in domestic,under the environment of MATLAB,using SimHydraulics software established the simulation model of the hydraulic system of flash welder's handpiece.On this basis,the dynamic response characteristics of the movable clamp are simulated and analyzed in the case of different structural parameters of the oil system and the load fluctuation.The simulation results show that with the increase of the diameter and the length of the tubing,the dynamic response speed of the movable clamp will be decreased correspondingly.The existence of the slope will affect the dynamic response of the moving clamp,but when the feed speed and the reverse speed of the movable clamp are the same,the influence of slope on dynamic response of movable clamp can be approximately eliminated.The change of the friction coefficient and the rail quality have great influence on the dynamic response speed of the moving clamp.With the increase of the friction coefficient and the rail quality,the dynamic response speed of the movable clamp will be greatly reduced.And the dynamic response speed of the movable clamp canbe improved by increasing the oil pressure and the output flow of the proportional valve.On the basis of the above simulation results,the measures of optimizing the oil circuit design and changing the control strategy to improve the dynamic performance of the welder are put forward.The dynamic response speed of the movable clamp can be improved by reducing the diameter and the length of the tubing connected to the A and B ports of the directional valve or the proportional valve.When the welding environment and rail quality change,the dynamic response speed of the movable clamp can be improved by reducing the friction coefficient between the rail and the roller and using a reasonable control algorithm to control the oil pressure of the handpiece hydraulic system and the output flow of the proportional valve,so as to reduce the influence of the welding conditions on the welding quality.And it provides direction for on-site welding quality assurance.