Autonomous aerial payload delivery with quadrotor using varying length cable

摘要

Full dynamics and control of a quadrotor unmanned aerial vehicle (UAV) transporting and delivering a payload connected via a length-varying cable are presented in this paper. It is shown that a coordinate-free form of equations of motion can be derived for this model without any simplicity assumptions that commonly appear in other literature, according to Lagrangian mechanics on a manifold. A geometric nonlinear controller is devised to transport the payload to a fixed desired position while aligning the cable along the vertical direction and considers the changes of the length in the direction of the cable. A rigorous mathematical stability proof is given using the Lyapunov theory and the desirable features of the proposed system and controller are illustrated by numerical examples.