Safety Protection Control Method Based On Cooperative Control For Train Formation Operation

The demand of rail transport has been growing around the world in recent years,because of its safe,fast,convenient and comfortable travel experience.With the continuous development of high-speed railways(HSR)in China,the operating mileage is increasing and the rail network is becoming more complex,which leads to the emergence of bottleneck sections.The capacity of the bottleneck section has a significant influence on the transportation capacity of the railway network.Using the existing railway resources to improve the capacity of the network is an opportunity but also a challenge for the development of HSR in the future.In order to meet the challenge of increasing the capacity and flexibility of the rail transport,scholars around the world have proposed a concept of Virtually Coupled Train Formation(VCTF)(or “Virtual Coupling”),which has received extensive attention from researchers in academia and industry all over the world in recent years.The Virtual Coupling makes the connection between trains no longer an actual physical coupler,but allows trains to maintain a short distance headway and a consistent velocity by train-totrain communication.The operation of VCTF breaks the limitation of the traditional safety breaking model that considers the absolute braking distance.This means that the interval between trains is greatly reduced but the risk of collision between each other is significantly raised.This thesis studies on the safety protection and control issues of VCTF operation,focusing on two levels: the safe braking model and safe braking control methods.The specific research contents are as follows:(1)The safety braking model applicable to trains in VCTF is studied.Based on the method of mechanism analysis and numerical analysis,the protection mechanism of the braking of VCTF is described,a safety breaking model suitable for train formation operation is constructed.Based on the relative coordinate system,a method for calculating the safety limit speed difference is proposed,which delineates the dangerous boundary for the speed fluctuation of the trains in VCTF.(2)The operation scenario of deceleration control of VCTF is studied.The deceleration control process of VCTF is transformed into a constrained optimization control problem based on the distributed model predictive control architecture.A deceleration operation algorithm of VCTF based on model predictive control is proposed.The effectiveness of the proposed method is verified through numerical analysis,and simulation experiments are designed to discuss the influence of the controller parameters on the effect of the control algorithm.(3)The operation scenario of emergency braking control of train formation is studied.The concept of relative kinetic energy is developed to quantify the collision risk of VCTF.With the optimization goal of minimizing the risk of train collision within the formation,a safety emergency braking algorithm is designed based on the centralized model predictive control architecture.Numerical simulations are conducted to compared the proposed algorithm with the adaptive cruise control algorithm and the maximum braking control algorithm.The results show the effectiveness of the proposed safe collision avoidance control method under the emergency braking scenario of VCTF.(4)Train formation operation simulation platform is designed and developed based on MATLAB/GUI programming technology.Through the design of typical scenarios,the effectiveness and performance of the control algorithms proposed above are verified based on the simulation platform.