Research On Route Optimization Of Simultaneous Pick-Up And Delivery Vehicle Routing Problem Under Travel Time Uncertainty

With the rapid development of social economy and Internet technology,online shopping has become an important part of People’s life.With the rapid increase of express business,express enterprises are facing more challenges.On the one hand,how the express delivery enterprise brings the distribution service with high timeliness to the consumers has become an important way to enhance the competitiveness of the enterprise,the uncertainty of the urban road in urban express logistics has become an important factor affecting the efficiency of distribution.On the other hand,the costs of distribution and transportation account for a large part of the total cost of logistics,facing the increasing express business volume,how to use the vehicle resources reasonably and reduce the distribution cost at the same time of guaranteeing the service quality has become a big challenge for enterprises.This thesis analyzed the road network data of Changsha and obtain the road network structure by using ArcGIS software.After analyzing the uncertain factors in the traffic network and the components of the road section impedance,the road section travel time data based on the road network structure data is obtained,and the interval data is used to measure the travel time impedance and the robust deviation criterion,that is,the maximum regret value,is used to define the robust cost.Then a multi-objective shortest path optimization model based on minimizing the maximum regret value is established to obtain the shortest path impedance among the nodes in urban express distribution network.Then,the vehicle routing problem with simultaneous pickup and delivery under interval impedance is studied,considering the nonsuperimposition of the travel time of vehicle,aiming to minimize the minimum completion time,the maximum regret of completion time and the total cost of distribution,a multi-trip and multi-objective vehicle routing optimization model with time windows is established and then designed a hybrid NSGA-Ⅲ—VNS algorithm to solve the model.At last,taking Changsha JingDong logistics distribution network as an example.By comparing with the optimal solution under certain conditions which take the mean value of interval as the value as section impedance.So the validity and superiority of the model and the algorithm are verified.The model built in this thesis fully considers the uncertainty of the actual distribution situation and the road section impedance,and provides the optimized solution and the theoretical basis for the vehicle route planning in the urban express logistics distribution.So the proposed route optimization model and algorithm have good practicability and universal applicability.