Research On Products Distribution Vehicle Routing Problem Of Nanjing Company

With the development of the market economy in our country, competition among companies is becoming more and more fierce. At the same time, the methods used by different corporations have been changing continually. In the past, they only focused on the quality of their products, but now the competition is everywhere, from the product price, channel of distribution to customer services.Logistics as a "third-party source of profit", has been great emphasis on domestic industries and the larger development. Distribution logistics as a major component part of the logistics, because its distribution costs increases in the proportion of logistics costs, how to solve the Vehicle Routing Problem (VRP) and how to optimizethe cost in the transportation of products, so as to satisfy the customers, various demands and make the company profitable, this question has appealed to many managers and researchers.In this paper, on the basis of investigation of "Nanjing SL product distribution"and analysis the data collected from Vehicle Routing Problem (VRP), some problems are found in the current distribution business system: line arrangement is unreasonable; utilization rate of vehicles is low; part of the network has low satisfaction because vehicles can not be reached in the time window.In order to optimize the product distribution system with the actual situation, the author builds the model of the VRPMTW with regard to weight coefficients, one depot,identical vehicles,vehicle capacity, delivery and time-windows constraints.Then, a improving genetic algorithm is proposed to solve the model.On the chromosome encoding, as number of distribution outlets is 87,a integer encoding similar to TSP is applied in this article,which the serial number of the network is randomly arranged. On the chromosome decoding,a method is used which is made by improving a novel decoding scheme—Split method is proposed to solve the model. In the design of chromosome selection, chromosome with the best are saved directly to the next generation,for the same chromosome only one is saved. In the design of chromosome crossover , OX method is used. In the design of chromosome muation , the 2 - exchange mutation is applied.After this algorithm are made by means of making MATLAB programs.In order to evaluate the performance of the proposed algorithm, the numerical experiments on one instances from related references are made, The results show the levation of optimization capabilities, efficiency and reliability.Then, the built model and the proposed algorithm are applied to this company, Seasonal distribution programs is applied for seasonal differences, finally, four seasons optimized distribution plan are given. the proposed program has increased distance distribution, utilization rate of vehicles and distribution cost ,and achieved good results, which improve the utilization of vehicles , achieve on time delivery and has impoved satisfaction.At the same time , reduce distribution costs and Improve profit margins for this enterprise.So,this Shows that the model and the algorithm is correct and effective.