Nonlinear control of a multirotor UAV with suspended load

This paper considers the control of a multirotor-type unmanned aerial vehicle (UAV) with a suspended load. The load is modeled as a pendulum, with a rigid link. We consider the case when the suspended load is connected to the centre of gravity of the UAV, and the interconnected system is modeled by Kane's method. A nonlinear controller based on the backstepping technique is derived, that ensures trajectory tracking of the UAV regardless of the pendulum motion. The origin of the tracking error is proved to be globally asymptotically stable, and results are verified by simulations.