The Area Division Of Express Delivery Terminal And Vehicle Routing Problem With Balance

The rapid development of the express industry accelerates competition among express companies.In order to improve the competitiveness,each enterprise exerts its strength in the links of the main line,the branch line and the last mile.The distribution network of last mile is very complex,and its operational efficiency has a great impact on the operation efficiency of the entire network.For enterprises who is the self-operated express delivery,routing planning is the key and district distribution is an effective method to reduce the scale of route planning.Partition distribution is widely used in actual end-delivery operations,but the zoning methods adopted by some delivery companies are not scientific,and it is difficult to ensure the balance of tasks between distribution units.Based on the above background,this paper studies terminal division and vehicle routing problem under the condition that the distribution unit tasks are roughly balanced.Firstly,it analyzes the characteristics of the terminal distribution of the express delivery,that is,the customer node is located in the residential area,the university area and the business office area(they are all named as the distribution community or the community),and the customer node is intensive;and every courier is responsible for several communities which are adjacent.Secondly,analyze the essence of the problem and establish a two-stage model.The traversal order of the customer nodes in the distribution community is essentially the TSP problem of relaxing the vehicle load limit;the essence of the terminal partition problem is to combine the community into different delivery units,if each community is regarded as having internal access mileage and total demand,this problem turn the into a vehicle routing problem.Therefore,a two-stage solution is proposed.The first step is to study the minimum traversal route of the customer nodes inside area,and the second step is to study the problem that the combination of community.This paper establishes a TSP model for traversing customer nodes in the region and a dual-target community combination model that considers task balancing and minimum total distribution cost.Design a two-stage algorithm to solve the model.The TSP model of the customer node is solved by the genetic algorithm.The problem of cell combination is a multi-objective model,which is solved by NSGA-? algorithm.The Solomon insertion algorithm is used to get the initial solution.The initial population is constructed by 2-opt and 3-opt,and the crossover operation is performed by string exchange,the mutation operation uses the inverse mutation operator.Finally,the simulation experiment is carried out by using the data of one express terminal of Y enterprise to solve the distribution division and delivery route of the network.Using Python to write a program to obtain a satisfactory solution for the total distribution cost and workload balance.Under the condition that the vehicle capacity is 250,the outlet is divided into 8 distribution units,and the operation time of each delivery unit is close to the average operation time.This can prove validity of the model and algorithm.Finally,it talk about the sensitivity on the results by the change of vehicle capacity,and the comparative analysis is carried out from three aspects:distribution cost,vehicle occupancy rate and delivery timeliness.Figure 30,Table 15,and 64 references.