Cooperative load transport with movable load center of mass using multiple quadrotor UAVs

This paper presents a strategy for cooperative load transport with movable load center of mass by multiple quadrotor UAVs. The load center of mass is modeled by a mass-spring system that moves in the x-y plane in time. The center of mass moving in the x-y plane by a sinusoid functions of time. We use the Newtonians law to derive the systems dynamics equations. The load is connected to the quadrotors by cables. The maximum thrust of the single quadrotor is less than required for load transportation. For this reason we use four quadrotor UAVs for load transportation. The leader-follower structure is applied for cooperate the quadrotors. We use a feedback linearization controller to control quadrotors along the z axis. Finally, some numerical simulations are considered to validate the proposed method.