The Traveling Salesman Problem With One Truck and Multiple Drones

We develop a novel mixed-integer programming (MIP) formulation for a traveling salesman problem with a truck-drone team, consisting of one truck and multiple drones, that carries out a set of deliveries. Our model takes an approach different from other MIP formulations in the literature. Benchmarks show that it can compete with those as well as with purpose-built exact solution methods but has the advantage of being easily implementable with an off-the-shelf solver. Additionally, we present an even tighter formulation for a special case where the drone range is non-binding. We conduct several numerical experiments to explore the performance of the model and to gain insights into the problem with multiple drones.