带时窗回程取货的车辆路径问题的算法

车辆路径问题如果考虑回程取货过程就可以在送货的过程中先后完成取货任务,比传统不考虑回程过程的问题更有实用性,基于此对传统问题进行了改进,不限制车辆的取送货顺序,而是设计了相应参数,避免了货物的重新排列·在确定目标时,综合考虑车辆运行成本、人员等待成本及服务成本等因素,实现目标解的真正可行·最后,根据此问题的特点,设计了先通过分枝定界法及遗传算法确定可行路线,再运用整数规划方法求解的算法,并以实例说明了算法的有效性·

On the Algorithm for VRPBTW (Vehicle Routing Problem with Backhauls and Time Windows)

Taking backhaul into consideration in the haul process,the vehicle routing problem with time windows (VRPTW) becomes the vehicle routing problem with backhaul and time windows (VRPBTW),which is more practical than normal VRPTW. The new problem VRPBTW is therefore proposed to improve the VRPTW so as to get rid of the limitation of haul/backhaul sequence by designing some parameters corresponding to the sequence and available to avoid its rescheduling. Furthermore,the costs of vehicle running,handling/waiting time and other services are all taken into account in defining the objectives,thus providing a definite solution to those objectives. According to the features of the problem,an algorithm is proposed for VRPBTW,of which the routing is feasibly determined via the branch and bound and genetic algorithm and then a solution is given by use of integral programming. An instance is given to prove its validity.