【作者】 张宏；

【导师】 王瑛；

【作者基本信息】 哈尔滨工业大学 ， 交通运输规划与管理， 2007， 硕士

【摘要】 物流配送是物流活动中直接与消费者相连的重要环节。在物流的各项成本中,配送成本占了相当高的比例。运输线路是否合理直接影响着配送速度、成本和效益。随着商品运输呈现小批量、多品种、多频次、及时性等趋势,多用户运输路径的确定更为复杂。因此,车辆路径优化问题成为研究者们竞相研究的热门话题。本文首先分析了车辆路径优化问题的研究现状,介绍了车辆路径优化问题的基本概念和车辆路径优化问题的分类及优化方法,使得对车辆路径优化问题有了整体认识。对带时间窗的车辆路径优化问题进行了数学建模,明确了问题的目标函数及约束条件,在比较多种方法之后采用遗传算法,采用扫描法生成问题的一个初始解,然后用遗传算法对初始解进行优化,得到了最优解或近似最优解。针对研究问题的特点,在遗传算法优化初始解的过程中,设计了遗传编码、适应度函数以及遗传操作策略。借助于MATLAB软件实现该算法,并通过实例证明了该算法是求解车辆路径优化问题的一个较好方案。计算结果表明了遗传算法解决此类问题的有效性。更多还原

【Abstract】 Logistics distribution is an important link with consumer directly, and takes account for considerable proportion in variable costs in logistics. The planning of vehicle routing in distribution will take great effect on the efficiency, cost and benefit. With a new trend of more kinds, less batch, high frequency and time restriction in materials distribution, the optimizations of the delivery route for multi consumers become more and more complicated. So, vehicle routing problem had become focus of many scholars to study.This paper gives a review of the past researches on vehicle routing problems and their solution methods. First, we introduce the concept of vehicle routing problems, classify vehicle routing problems and optimized methods, which make us understand the whole vehicle routing problems. Meanwhile, we construct a mathematical model, define an objective function and constraint mathematically then solve it based on Genetic Algorithms. An initial solution is constructed by the Sweep Algorithms. Then GA is used to improve it to acquire a best or better solution. We propose coding strategy, fitness function and three genetic operations when using GA. Finally, this method is implemented on computer with MATLAB. GA in this paper can obtain an optimized solution effectively and has been proved to be a good scheme to solve vehicle routing problems.更多还原