Hybrid ant colony algorithm based on vehicle routing problem with time windows

Vehicle routing problem with time windows (VRPTW) is an NP-complete optimization problem. The objective of VRPTW is to use a fleet of vehicles with specific capacity to serve a number of customers with fixed demand and time window constraints. A hybrid ant colony system (DSACA-VRPTW) is proposed to solve this problem. Firstly, each ant's solution might be improved by dynamic sweep Algorithm which makes improvement to the solutions by grouping the customers. Then a new improved ant colonies technique is proposed, after all colonies are in the state of stagnation, communication among them is carried out in order to do favor to leave the local peaks. Finally, Solomon's benchmark instances (VRPTW 100-customer) are tested for the algorithm and shows that the DSACA is able to find solutions for VRPTW.