Modelling and Optimization Algorithm for Solving Vehicle Routing Problems of Finished Product Re-depositing in Steel Plants

The characteristics of finished product re-depositing problems in steel plants are analyzed.After transportation tasks being decomposed,the original problems are transferred to vehicle routing problems with constraints of latest visiting time and of number of vehicles which are simultaneously visiting the same warehouse.Consequently,a 0-1 program model is presented,and an iterated local search(ILS) algorithm is designed to solve the problems.The initial solution is generated by a greedy heuristic approach.Local search procedure is designed by combining four well-known local search operators.Perturbation operator adopts variable intension 2-opt* operator.The vehicle dispatching and vehicle route optimizing can simultaneously be done with the algorithm.The model and algorithm are tested by citing randomly generated problem instances.Computational results show that the model and algorithm are effective for solving this kind of problems.