| With the deepening of urbanization,the increasing of population become more and more fast,and the traffic congestion problem becomes more and more serious.Owing to the characteristics of large capacity,safety and punctuality,metro train is one of the most popular transportations for metropolis city to overcome traffic congestion problems.In recent year,cities such as Shanghai,Guangzhou,and Beijing have built the metro lines which adopted the express/local operation.The scale of metro network has been further enhanced.Owing to the increasing of operation mileage,the energy consumption of metro systems is growing rapidly.With the increasing shortage of energy sources,it is urgent to search the energy-saving measures for metro system.Previous researches on the energy-efficient strategies of metro system most focused on the general metro lines.It is necessary to search the energy-saving methods for the skip-stop metro line.This paper focus on the cooperative control of metro trains under the skip-stop pattern,taking into account the utilization of regenerative energy for energy saving and the constraint on the minimal headway for safety.To synchronize the motoring and braking trains for better utilization of regenerative energy,the motoring operation mode is allowed more than once in the proposed train driving strategy,which considering the characteristic of skip-stop metro line.Then the overall optimization of cooperative control on multiple trains is decomposed into a series of local optimizations based on the rolling optimization framework,and a cooperative control model for express/local trains is proposed to minimize the net energy consumption.Finally,a hybrid genetic algorithm is developed to solve the proposed model.Main contents of this study are as follows:(1)An optimized driving strategy for express/local trains is proposed to improve the utilization of regenerative energy,taking into account the characteristic of skip-stop metro line.According to the proposed driving strategy,the motoring operation mode is allowed more than once in each inter-station run to improve the utilization of regenerative energy.And the strategies of partial motoring in train acceleration and partial braking in station stopping are also adopted in the proposed driving strategy to achieve better net energy reduction.Case studies indicates that the net energy consumption of metro train under the propose driving strategy is reduced by 3.55%,compared to the Four-phase Control Strategy.(2)In this paper,the overall optimization of cooperative control on multiple trains is decomposed into a series of local optimizations by means of the rolling optimization mechanism.The local optimization is triggered whenever a train departs from the station.For each local optimization,the central train control center devises the energy-efficient trajectory of the departing train in the next inter-station run,considering the real-time information including the weight of the departing train and trajectories of the other trains in their current inter-station runs in the same or adjacent power supply region.Then the coordinated control model for express/local trains is proposed,aiming at minimize the net energy consumption of skip-stop metro line.Case studies indicate that,the net energy can be reduced by 3.81%in comparison with the separate control.(3)A series of rules are designed to ensure the train trajectories obtained by solving the proposed cooperative control model satisfies the constraint on the minimal headway.Case studies on a real-life metro line demonstrate the interval between adjacent trains is longer than the minimum dynamic tracking distance from beginning to end.(4)The practical timetable in the peak hours are adopted in the case study to verify the practicality of the cooperative control model.The results show that the cooperative control with partial motoring/braking reduce the net energy consumption by 6.65%when compared with the separate control. |
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