Longitudinal Dynamics Simulation Of Heavy Haul Combined Train Based On Central Locomotive Disturbance

While the heavy-haul combined train increases the capacity and brings extremely high economic benefits,it also has a large longitudinal impact during operation,especially the longitudinal force state of the slave locomotive located in the middle of the train is also more complicated.Under the braking condition,there have been many accidents in which the central slave locomotive separated from the latter vehicle.This is because when braking,the central slave locomotive will be blocked by the front and back of the vehicle,resulting in an excessive pressure hook force,which increases the risk of the coupler jumping out and affects the running safety of the train.Therefore,in order to reduce the longitudinal coupler force of the heavy-hual combined train,it is of great theoretical value to study the control strategy of the heavy-duty combined train during braking.In this thesis,according to the research ideas of simulation model construction,disturbance factor analysis,and braking strategy comparison and verification,the longitudinal dynamics simulation research of heavyhaul combined train is carried out.Firstly,based on the theory of train longitudinal dynamics,a simulation model was established,and the validity of the model is verified by comparing it with the test coupler force data.Using the simulation model,the factors affecting the longitudinal impulse of the train are analyzed,and the characteristic factors that the disturbance of the central slave locomotive mainly affects the longitudinal impulse of the front and rear trains are obtained.Secondly,according to the braking conditions,the influence of different braking modes on the longitudinal force of the train is analyzed.On the strategy of braking mode,a coordinated control method of air braking and locomotive electric braking during the dynamic running of the train is proposed.Then,aiming at reducing the coupler force on the train,an asynchronous braking strategy is proposed to change the application mechanism of the locomotive’s electric braking force.The simulation analysis shows that the asynchronous application of the electric braking force of the locomotive can be well applied to the braking of long downhill or variable ramps,and to optimize the longitudinal force of the train and the central slave locomotive.Finally,combined with the actual line conditions and the delayed response of the central slave locomotive,the asynchronous braking strategy is simulated and compared.The results show that the strategy can optimize the longitudinal force of the train when braking on the downhill,and relieve the front and rear of the central slave locomotive.The phenomenon of swell after blocking can provide a reference for the braking strategy of trains in actual operation.