The Simulation Model Of Vehicle Routing Problem With Time Windows

Vehicle Routing Problem(VRP) is a hot topic in the fields of logistics. Correct routing will decrease the delivery costs for service provider and increase customer service quality Vehicle Routing Problem with Time Windows (VRPTW) becomes a noticeable problem with the development of logistics distribution and the additional demand from customers, which add a visiting window to conventional VRP.Since the VRPTW has been proved to be a NP-hard problem, there is no effective method to solve it thoroughly. Various algorithms have been used to solve the problem. However, there are shortages for these algorithms, for example, lacking considering actual factors and solving VRP statically. This research tries to establish the simulation model to study VRPTW. Iterative simulation experiments and data analysis accelerate the speed of VRPTW's solution. The main researches of the work are as followings.(l)System analysis is carried out for vehicle routing programming system, and corresponding mathematical model is established considering stochastic factors. Based on the mathematical model and via object-oriented method, the objective and attribute analysis is provided firstly, and then function model is established based on IDEF0.(2)A simulation model is established which has the blocking, hierarchical and object-oriented characteristics, based on the simulation tool of eM-plant. Via the simulation language simTalk, a program for resolving VPPTW is developed and embedded into the simulation model.(3)Simulation experiment is designed in order to provide decision-making reference for vehicle routing programming through model running and result analysis. The influence that the time windows, customers, vehicle types, vehicle running states impact on the custom satisfaction and service costs is considered fully.