A Multi Ant System based hybrid heuristic algorithm for Vehicle Routing Problem with Service Time Customization

Abstract

This paper addresses the Vehicle Routing Problem with Service Time Customization (VRPTW-STC), which is an extension of the classic Vehicle Routing Problem with Time Window (VRPTW). In VRPTW-STC, the decision maker tries to find an optimum solution with the smallest fleet size, the lowest travelling distance as well as the largest total service time of all customers. The objective to enlarge each customer’s service time obviously conflicts with the need of reducing both changeable and fixed transport costs, i.e. travelling distance and fleet size. At the same time, the routing plan must meet the time window constraint and the vehicle capacity constraint. To solve this problem, we designed a Multi Ant System (MAS) based hybrid heuristic algorithm inspired by to decompose a multi-objective problem into several single objective ones. Then, Ant Colony Optimization (ACO) algorithms are applied to every single-objective problem. A unique global best solution is maintained to record the current best solution. The global best solution will be updated when a new feasible solution found by any ACO dominate current global best solution. Several local search algorithms are also incorporated into MAS to help improve the solution quality. Solomon’s benchmark tests are used to test the effectiveness of the proposed algorithm. The computation experiment results show that our proposed MAS based hybrid heuristic algorithm performs better than typical existing algorithms.