Coordinated transport of a slung load by a team of autonomous rotorcraft

This paper describes a hierarchical approach to coordinated transportation of a slung load by a team of autonomous helicopters. A closed-loop controller computes net force and moments on the load's center of gravity so a desired trajectory is followed; cable forces at each attachment point are computed so that the net force and moment on the center of gravity equal the desired values from the controller; finally each helicopter's position, velocity, and thrust are computed to obtain the desired attachment force, assuming a compliant cable connects the helicopter to the load. Results of simulations showing four degree of freedom transport of a load (North, East, Down position and yaw angle) show the utility of the proposed approach.