Integrated Train Trajectory Optimization for An Urban Rail Transit Line based on MILP

This paper focuses on the train trajectory optimization problem to reduce the tractive energy consumption for trains running on an urban rail transit line and used the mixed integer linear programming MILD approach based on the typical train dynamics model to solve the optimal problem. Firstly, the integrated non-linear trajectory planning model for trains at inter-stations is introduced. Then the integrated trajectory planning problem is reformulated as a mixed integer linear programming problem by applying several transformation properties in the optimal model. The MILP problem can be solved by existing solvers, e.g., CPLEX. A case study based on the data of Changsha subway line 4 is conducted to assess the performance of the proposed model and approach. Simulation results show that the reduction of energy consumption is about 27 % by using MATLAB invoking CPLEX to solve the MILP problem.