Research On Container Collection And Distribution Problem Under Uncertain(un) Loading Time Based On Nominal Value

As a new type of transportation mode,truck-trailer has the characteristics of high loading and unloading efficiency,high degree of cooperation and good economic benefits.It has been adopted in developed countries and regions in Europe and America,and China is still in the stage of pilot promotion.With the continuous improvement of China's economy,the volume of import and export trade is increasing year by year,and the effective operation of local port collection and distribution will play a vital role in the optimization of port operations.As an important part of the port container collection and distribution system,the truck-trailer can effectively shorten the waiting time of the tractor and improve the utilization efficiency of the tractor.It has a good optimization significance for the port collection and distribution system.Compared with the traditional transportation mode,the truck-trailer effectively utilizes the loading and unloading time of the customer,and the tractor and driver resources are changed from the waiting mode in the traditional mode to the effective operation in the truck-trailer mode.Therefore,the loading and unloading time constraint at the customer is crucial for generating a tractor scheduling strategy in the transport mode.However,in actual operation,the loading and unloading time of the customer is often uncertain when the tractor scheduling strategy is generated.Therefore,the tractor scheduling strategy that processes the loading and unloading time of the customer into a certain value is often biased during execution.Considering that the actual loading and unloading time will be deviant,in order to make the generated scheduling plan to prevent the uncertainty of loading and unloading time to some extent,and pursue the goal of minimizing the total cost of the original problem system,the robust optimization method is used to solve the problem of container truck-trailer under the uncertain loading and unloading time,which can make up for the deficiencies in the research of deterministic problems,and make the research of the truck-trailer closer to the actual situation.This paper firstly considers the uncertainty of loading and unloading time based on the truck-trailer separation and empty container sharing.According to the robust optimization theory,the container collection and distribution problem model based on the nominal value of uncertain loading and unloading time is established.Then the Zoutendijk feasible direction method is introduced,and the optimal service time and robust solution of the scheduling sequence are calculated by MATLAB software programming.Finally,some random scenes are generated,and numerical experiments are carried out to verify the validity of the model and method.Experiments show that although there is no final solution with minimum total cost and maximum robustness,the relationship between minimizing total cost and maximizing robustness can be weighed.In addition,three robust evaluation criteria are proposed,we obtain the influence trend of uncertain numerical value and uncertain proportional parameters on three robust evaluation criteria has a certain reference value for the container carrier to make a scheduling plan.