Multi-objective Vehicle Routing Problem with Unpaired Pickup and Delivery Demands using NSGA-II Algorithm

With the rapid development of express delivery business, the vehicle routing problem has become more diversified and personalized in order to solve the real business problem. In an emergency, the spare parts supply system needs to deliver directly to the demand point after picking the spare parts. When there are multiple spare parts and stations in the transportation system, vehicle decisions include routes, pick-up and delivery plans. We choose the minimum operating cost and maximum customer satisfaction as optimization goals upon meeting customer demands. The optimization problem is modeled as a multi-objective VRP with unpaired pickup and delivery demands considering time-window. We innovatively proposed an ensemble model approach to solve the unpaired pickup and delivery demands and vehicle task assignment problems. The NSGA-II algorithm is applied to solve the multi-objective VRP and an innovative demand-first scheme is adopted. Including large-scale and small-scale experiments show that the scheme proposed in this paper can solve various problems efficiently. The algorithm can solve practical problems and improve benefits for transportation teams.