Study On VRP Of Combination Of City Distribution Center's Owned And Leased Vehicles

In recent years, accompanying with rapid development of economy and increasing speed of urbanization process, the need of logistics delivery based on cities is being on arise. While Chinese city distribution center is still facing a series of problems, such as high distribution cost, unsatisfied service quality, strict urban traffic control rules, etc. Taking the problems mentioned above as my reseach's goal, this paper does such things as following:Firstly, on the basis of the analysis of status quo of city distribution centre in our country, the paper research the reason why the model of the combination of distribution center owned and leased vehicles has been adopted so popularly in our country. From this, we can conclude the model's existing is reasonable and inevitable.Secondly, combining the statistics data of distribution center vehicle usage, we calculate the reasonable size of city distribution center by using cost - benefit analysis method . It is a effective way to reducing the cost of logistics distribution by determining a reasonable scale of its own vehicles. This paper introduced the concept of delivery cycle to correct the method of calculating the distribution center's demand for vehicles as a day as the unit of the distribute cycle. As a result, it gets a more accurate statistic data reflecting on the distribution center's use of trucks. Then, considering different customer service level of self-owned and leased vehicles, establishing the model of minimum cost and the largest profit respectively, we can work out a reasonable distribution center city owned vehicles size. And the paper uses two algorithm cases to confirm the feasible of the model and algorithm.Finally, this paper builds the VRP model of combination of two types of vehicles under strain of time windows, and use the ripe C-W algorithm combined with algorithm designed in the paper to solve the model. Through these, we can not noly determine the number of the vechicles the centre needs, but also assign the path to the reasonable vechicle. The VRP of the combination of distribution centre's owned and leased vehicles is the heart of this paper. And it's also another effective way to reduce the cost of logistics distribution for distribution vehicle center setting reasonable distribution path. Based on the analysis of the difference of the features of delivery by centre owned between leased vehicles, the paper builds the model of VRP of combination of two type vehicle. As for the solution of optimization model, this paper will first decomposes the problem of combination of centre owned and leased vehicles into two extreme cases: one case is that distribution center having enough vehicles to complete all tasks and the other is that distribution center outsourcing the tasks completely. Through C-W saving algorithm in both cases, we can get the best cars distribution path, and finally use cost comparison method to determine the number of the leased vehicles and the best path to them. At last the paper uses an algorithm case to confirm the feasible of the model and algorithm.