Research On Train Control Considering Longitudinal Dynamics Of Freight Trains

With the large-scale operation of heavy-haul trains in our country,the daily number of heavy-haul trains is increasing,and higher and higher requirements are put forward for the operation quality of heavy-haul railways.In order to improve the quality of heavy-haul railway operation,replacing manual operation with a highly automated centralized control system to improve train safety,stability and energy saving has become the only way for the development of heavy-haul freight in our country.Heavy-haul trains are heavy in weight,long in marshalling groups,and the length difference between the full train pressure and the coupler length can reach several meters.In addition to the complicated line conditions,large longitudinal impulses are prone to occur during train operation.In severe cases,it can cause decoupling and breaking of couplers or even train overturning,causing serious harm The train runs safely,so it is necessary to add the longitudinal force index to the study of the control algorithm of the heavy-haul train.This paper studies the control algorithm of heavy-haul trains from the perspective of reducing the longitudinal impulse of the train,reducing the energy consumption of the train operation,and reducing the ability to track the target speed curve.First,the longitudinal dynamics model of the train is established based on the differential equations of the kinematics of the heavy-haul train,considering the loading and unloading characteristics of the coupler buffer,and using the Zhai method to solve the differential equations of the longitudinal dynamics of the train.Secondly,extract and summarize the existing safety and stable operation rules of Shuohuang Railway,and bring them into the simulation verification of the longitudinal dynamics model of heavy-haul trains,and transform them into safety and stability constraints with quantitative indicators.Then,the heavy-haul train operation control problem,which considers the longitudinal impulse of the train,the running energy consumption and the tracking index of the target speed curve,is transformed into a problem conforming to the model predictive control framework,and the safe and stable operation criterion with quantitative indexes is introduced into the constraint conditions.The design is based on Speed tracking controller for model predictive control algorithm.The controller takes the target speed curve as input and train traction/braking force as output.The prediction model can output the control variable sequence that reaches the optimal index in the prediction time domain,and the first control sequence is selected as the control variable to act on the longitudinal dynamics model of the train for solution.Select typical working conditions to verify the longitudinal dynamics model of heavy-haul train established in this paper.The simulation results show that the longitudinal dynamics model of the heavy haul train established in this paper is consistent with the actual train under typical working conditions.Finally,part of the Xibaipo to Suning North section of the Shuohuang Railway and the “1+1” formation of 20,000-ton heavy-haul trains on the Shuohuang Railway were selected for simulation verification.Carry out the simulation analysis of the influence of different weight coefficients and different prediction step lengths on the control effect,and compare with the actual vehicle operation example.The simulation results show that the heavy-haul train control algorithm considering the longitudinal dynamics is effective in reducing the longitudinal force of the train,reducing the energy consumption of the train,and improving the tracking ability of the target speed curve.