Optimization Of Vehicle Routing Problem For City Logistics Distribution

With the acceleration of urbanization process, urban size and land using, national policies that support to the healthy development of the logistics industry in our country, the development of the urban logistics has been becoming a hot spot in recent years. City logistics system is a kind of the logistics system by region division, urban logistics consists of seven parts, such as packing, handling, transport, storage, distribution processing, distribution and information, especially distribution is one of core factors, the urban logistics distribution network system is one of core subsystems of urban logistics system, with regard to system. A modern urban logistics system must have a modern urban logistics distribution network system, optimizing urban distribution network is the essence of whole city, then carrying cargo safely to the right position in accordance with the requirements of customers, in the distribution process, the number of vehicles, mileage operations, environmental pollution should be as possible as less, this is also the typical vehicle routing problem. Because of number and layout of urban customer, transportation and policies, the urban distribution vehicle routing problem has many limitations and restrictions, so combining the actual of urban distribution, time of client choosing, rate on vehicle and so on, the time-dependent vehicle routing problem with time window(TDVRPTW) becomes the research object.Through consulting a large number of literatures, this paper first summarizes the concept and related algorithm of vehicle routing problem, still describes in detail the connotation and function of urban logistics distribution system, and analyzes and study the characteristics and the formed key factors of urban distribution system; Then based on the characteristics of urban logistics distribution and the definition of vehicle routing problem’s basic conditions, this paper analyzes and establishes the related mathematical model about urban distribution routing problem under the condition of time-varying with time window; Finally this paper study the problem of algorithm, incorporating clustering theory into path optimization algorithm, and designs the two-phase heuristic algorithm based on fuzzy clustering and artificial colony: in the first stage, this paper makes fuzzy clustering analysis about customer groups, breaking the original administrative divisions, and divides customer groups into different classifications, thus reducing the scale of original problem; in the second stage, this paper improves nectar source selection probability formula of the original artificial colony algorithm, and adds to the disturbance factor related to iterations and honey good ratio, and solves the shortcoming that late iteration algorithm may run into local optimum. Using r101 test data in standard test database that Solomon designs Benchmark Problems, this paper uses the matlab to program, making clustering simulation in the algorithm’s first stage and making specific route planning experiment simulation to the division’s classification in the algorithm’s second stage, and makes comparison with general artificial colony algorithm’s computation results. Finally taking the distribution of Chongqing Tianyou Dairy Co., LTD’s own stores for example, through concrete analysis, this paper optimizes its specific distribution route.Based on the characteristics of urban distribution in this thesis, the mathematical model of TDVRPTW is advanced, a fuzzy clustering-artificial bee colony algorithm is designed, analysis of typical case verifies effectiveness of the mathematical model and feasibility of the algorithm. According to urban distribution characteristics, the mathematical model and algorithm contribute to making more reasonable distribution project, and providing a basis for decision-making in routing-optimization of city logistics distribution.