Optimization Of The Depot Shunting Scheduling Problem With Flexible Operation Items And Sequence

The EMU depot is an important place for the maintenance,repair and parking of EMUs.When EMUs enter the EMU depot for maintenance or parking,the EMU depot needs to reasonably arrange the various operations of EMUs during the period to avoid operation conflicts between EMUs.The plan for arranging the operation process is called the depot shunting schedule.With the increasing number of online EMUs and the amount of maintenance tasks,the existing planning methods are increasingly difficult to meet the actual needs.The existing research is not fully applicable to the actual situation of the depot shunting schedule in China’s current EMU depots.The main defects are that the operation items and sequence of the EMU can be adjusted,and the topological structure of the EMU depot is not sufficiently detailed.Therefore,on the basis of the previous research on the optimization of the depot shunting scheduling problem,this thesis studies the optimization of the depot shunting schedule considering the flexible operation items and sequence,and some tracks with two parking positions.The main contents are as follows:(1)The basic functions and facilities and equipment of the garage is introduced and the operation items and operation processes of EMUs in the EMU depot is analyzed.According to the differences in the operation status of EMUs,EMUs operating in the EMU depot are divided into two categories: EMUs that meet the maintenance conditions and EMUs that do not meet the maintenance conditions.Then the definition and content of the depot shunting schedule is described.The influencing factors of the depot shunting schedule in EMU depot are summarized as five categories: the layout of the EMU depot,the regional setting of facilities and equipment in the EMU depot,the type and number of tracks in the EMU depot,the type and number of EMU marshalling,and the operation content and sequence of the EMU depot,and the preparation process of the depot shunting schedule in the EMU depot is given.(2)The information contained in the signal plane layout of the EMU depot is analyzed,and a modeling method for the topological structure of the EMU depot is proposed.After comparing and selecting the three existing typical topological structure modeling methods,the topological structure diagram of the EMU depot is established by taking the signal machines,insulation joints and the EMU blocks of the EMU depot as nodes and the track circuit sections between the two nodes as edges.According to the type of access to the operation track,the route is divided into six categories: washing route,temporary maintenance and roller route,storage route,inspection route,traction route and exit route.The attributes of route table are set as route name,route beginning and end point,route type,route direction route,corresponding parking position,route track section and route length,and the method of creating route table is given.(3)The concept of route mode is introduced,and the route mode includes the operation items,the order of operation items,route and the time information of each resource occupied by the route.Based on this,the optimization problem of the depot shunting schedule is transformed into the constraint assignment problem of assigning one route mode for each EMU.The objective function is the minimum linear weighted sum of the total travel distance and the total travel time of EMUs in the EMU depot.The constraint conditions include the uniqueness of the route mode assignment of the EMU,the non-conflict occupancy of the track section and the track parking position.Based on this,the linear 0-1 programming model of the depot shunting schedule of the EMU depot is constructed.Based on the maximum clique of the interval graph,the maximum incompatible route mode set can be obtains.Then,the nonconflict constraint of the occupancy of track sections and track parking position can be constructed.In conclusion,the structure of the model is compact,and the optimal solution can be obtained in polynomial time.In order to cope with the possible infeasible situation of the model,the strategy for dealing with the infeasible situation is given from the perspective of adjusting the maximum waiting time of the EMU at the storage track/inspection track.(4)In order to test the correctness and effectiveness of the proposed method,a small example and a large example are constructed based on the actual data of Guiyang North 1th EMU depot and Guiyang North 2th EMU depot.By adjusting the maximum waiting time of the EMU on the storage track/inspection track and the storage track of EMU starting entry,four route mode creation rules are designed.The solution results of small examples show that,according to the maximum waiting time of 110 min,the rule without specifying the storage track can be optimally solved in 12.35 s,and the solution quality is better than the other three rules.The solution results of large examples show that,according to the maximum waiting time of 60 min,the optimal solution can be obtained in 163.42 s by using the rule without specifying storage tracks,but the rule of prioritizing the nearest storage track for the EMU can obtain the solution that gap not exceeding 0.03 % in 12.67 s.Therefore,the calculation efficiency of the latter is better than that of the former.