Leader-Follower UGV-UAV Formation as Control Paradigm for Package Delivery

This paper addresses the problem of package delivery by a drone taking off of a ground vehicle, flying towards a desired delivery point and flying back to land on the ground vehicle. Specifically, the final step, when the drone approaches the ground vehicle and lands on it is dealt with here. To do that a ground mobile robot, a Pioneer 3-DX unicycle platform, is used to play the role of the delivery truck, whereas the drone is the Bebop 2 quadrotor. To control such a formation the leader-follower control paradigm is adopted, in which the Pioneer 3-DX is the leader and the quadrotor is the follower, which mimics the movement of the leader. According to such a control paradigm, the two vehicles are independently controlled. A first controller is responsible for the leader and a second one is responsible for the follower. Aiming at a package delivery application, the leader robot is programmed to follow a given path, thus playing the role of a delivery truck, whereas a trajectory-tracking controller is designed for the follower, having the leader as the trajectory to be tracked. Therefore, the leader-follower control paradigm fits quite well the application in mind, which is the reason for this proposal. Simulation results considering such a system are presented here, which validate the proposed approach.