Optimization Of Cold Chain Logistics Distribution Route Based On Actual Road Network

In recent years,with the rapid development of the cold chain logistics industry and the impact of the global epidemic,more and more residents began to buy cold chain products through online shopping.Because most cold chain products are easy to deteriorate and difficult to preserve,compared with general goods,cold chain products have higher requirements on delivery timeliness.This also makes the cost of cold chain logistics in the terminal distribution link remain high.In addition,the complex traffic conditions in the urban road network also bring great challenges to the distribution service.Therefore,it is of more practical significance to optimize the distribution at the end of the cold chain in the actual road network environment with dynamic changes.Focusing on this point,the following research works are completed in this dissertation:(1)In order to describe the urban road traffic network,this dissertation first analyzes the principle and characteristics of the two ways to build the road network model in graph theory: the original abstraction method and the dual abstraction method.This dissertation uses the original abstract method to establish the static model of urban road network after analyzing the elements of urban road network.Then access to baidu map path planning module through the crawler to obtain the road passage time.Since the road travel time presents the characteristics of multi-peak,multi-peak Gaussian fitting is selected to fit the data to obtain the travel time curve,so as to describe the dynamic characteristics of the road network and establish the actual road network model combining static and dynamic.(2)Based on the actual road network model with time-varying characteristics,the optimization model of the end distribution of electric vehicle cold chain logistics was established,taking into account the capacity constraints,driving distance constraints,charging rules and other restrictions of the number of distribution vehicles.The sum of fixed cost,transportation cost,cargo damage cost and time penalty cost is minimized as the objective function.(3)A case study of a logistics enterprise distribution center in Qingshan District,Wuhan.The time-varying road network model is constructed for the main road network within the service scope of the distribution center,and MATLAB software is used to solve the optimization model of the end of the cold chain distribution under the timevarying road network model,and the optimal distribution scheme is obtained.At the same time,the distribution optimization model under the static road network model is solved,and the optimization schemes under the two states are compared to verify the validity of the model proposed in this dissertation.