Abstract: A fuzzy programming model was built to optimize total cost of vehicle routing problem, where vehicle travel time and customer service time were fuzzy. The mode was firstly converted into a deterministic one, and then it was solved by a discrete particle swarm optimization algorithm which redefined the equation of particle motion and algorithms of discrete variables and designed exclusion operator to maintain the population diversity. In comparison with both standard genetic algorithm and standard particle swarm optimization algorithm, it can effectively avoid the search being trapped into local optimum and achieve satisfactory results.

Key words: Vehicle routing problem,Fuzzy travel time,Discrete particle swarm optimization algorithm