Research On Vehicle Routing Optimization Of Cold Chain Logistics Based On Traffic Speed

With the development of social economy and the continuous innovation of business model,China's cold chain market has entered a golden period of rapid development.Many enterprises have begun to innovate and develop cold chain product business,and the state has also constantly issued policies and regulations to support the development of cold chain industry.Cold chain distribution is the core link of cold chain logistics.Compared with ordinary products,cold chain products are perishable and vulnerable,and the timeliness requirements of distribution are higher.However,the increasingly serious urban traffic congestion seriously affects the quality of cold chain logistics distribution and leads to higher cost of cold chain logistics,which to some extent restricts the development of cold chain market.According to statistics,the loss caused by the transportation of cold chain products in China is up to hundreds of billions,most of which occurs in the field of urban distribution.In order to tap the "third profit source" of cold chain logistics,this paper mainly focuses on the vehicle routing problem of cold chain logistics,and puts forward a set of integrated solutions.The main contents are as follows:(1)In order to quantitatively characterize the traffic state of the road network,this paper proposes three methods for obtaining the speed of the road network.Based on the detailed analysis of the three methods for obtaining the speed of the road network,including the traffic index,mobile phone positioning technology,and electronic map software,from the accuracy,Analyze and compare the advantages and disadvantages of the three methods in three aspects: availability and cost.Because the map software has the characteristics of high accuracy,strong availability,and low cost,this article chooses to use the map software to obtain the speed of the road network;use the python programming tool to crawl the speed of the road section in the traffic situation module of the high moral map,according to the data Peak characteristics,fitting multi-peak Gaussian function to point data to obtain road network speed function,providing basic data for the model;proposing a calculation method for route transit time.To verify the effectiveness of the calculation method,the transit time of a route is carried out After calculation,the comparison with the actual situation shows that the method has high calculation accuracy and can provide basic data for cold chain logistics distribution.(2)This paper proposes a cold chain logistics vehicle path optimization model based on the actual traffic network and traffic speed.The model introduces virtual nodes to build an abstract model of the actual traffic network,considers the speed change of each road segment,and uses fixed costs,transportation costs,and cooling.The minimum sum of cost and time penalty cost is the objective function,which is constrained by the conditions of the customer node time window,vehicle load,service rules and other conditions,and on the basis of elaborating the principle and steps of the single parent genetic algorithm,a single parent is designed for the model Genetic algorithm solution process.(3)An example analysis was conducted by a fresh food distribution company in Beijing to verify the validity and necessity of the model.On the basis of setting model parameters and establishing an abstract model of Beijing's urban road network,the model is solved with the help of matlab programming tools,and after multiple runs of the program,the optimal plan for the vehicle's vehicle routing is obtained,and the vehicle is described in detail in the distribution process.Analysis of the obtained scheme shows that the solution obtained by the model in this paper is ideal in terms of full load rate and time window,and the necessity of this model is verified by the selection of a certain line.There are 36 pictures,16 tables and 57 references in this paper.