Scheduling Optimization And Operation Mode Analysis On Ro-Ro Tractor-And-Trailer Transportation

In recent years,the Ministry of transport has attached great importance to ro-ro tractor-and-trailer transportation.Scholars have relatively little research on ro-ro tractor-and-trailer transportation at home and abroad.Most scholars have studied the scheduling of land roll tractors,the comparison of whether to use tractors in the wharf,and the scheduling of empty trailer tractors.The traditional ship type of ro-ro ship is "stern door opening".When the tractor carries out the loading and unloading task,the unloading task is completed firstly,and then the loading and unloading task is carried out.With the large-scale of the ship and the frequent circulation of goods at home and abroad,the ship type of the existing ship can no longer meet the cargo flow.In 2020,the newly operated "Zhonghua Fuqiang" and "Zhonghua Fuxing" ship types will be changed.The bow and stern of the ship type will be "straight in and straight out".Compared with the traditional operation mode of the tractor of roro ship,the operation space range of tractor under new ship type is different,and its operation mode and scope of application are also obviously different.Based on the characteristics of "straight in and straight out" of the bow and stern of the new ship type under the conditions of different ship types,this thesis designs the operation mode of "loading and unloading" and makes an analogy analysis with the operation mode of "unloading first and then loading" of the traditional ship type.Under this premise,taking the operating cost of tractors as the objective function,the hybrid integer planning model of terminal tractor scheduling optimization for ro-ro and hanging transport is constructed,and the differences and applicability of tractors in the operation mode of "loading and unloading" of the new ship type and the "unloading before loading" operation mode of the traditional ship type are studied.Through the analysis of model characteristics,combined with the principles of genetic algorithms,the model is designed and solved.Finally,an example is designed and the experimental results are analyzed combined with the actual data of the port.Through the calculation examples of the number of loading and unloading tasks of different scales,the experimental results of CPLEX and genetic algorithm are compared and analyzed.Compared with the traditional ship type "unloading first and then loading",the new ship type "loading and unloading" operation mode has the following characteristics:(1)the new operation mode can reduce the operating cost by about 15%;(2)When loading and unloading tasks are densely distributed,the operation cost of unloading tasks close to the bow is higher;When loading and unloading tasks are sparsely distributed,the operation cost of unloading tasks far from the bow is higher.(3)Overall,the operating cost of the “loading while unloading” operation mode is lower than that of the “unloading before loading” operation mode.Under the “loading while unloading” operation mode,the above research conclusions can provide decision support for the operation scheduling of the ro-ro tractor-and-trailer transportation optimization.In this thesis,from the perspective of the tractors in the wharf,combined with the characteristics of the new ship type "bow and stern straight in and out",the newly designed operation mode of "loading and unloading" has the advantages of low operating cost and high operating efficiency of tractors,which provide theoretical support and decision support for the scheduling of port cargo rolling and hanging operations.