Design and development of a free-floating hexrotor UAV for 6-DOF maneuvers

This paper presents design and development of an experimental testbed for nonlinear geometric controls of a rigid body. We develop a fully actuated hexrotor UAV that uses six variable pitch propellers to control six degrees of freedom maneuvers, namely three position and three attitude variables, independently. In contrast to the popular quadrotor UAVs that can hover at a single attitude, the hexrotor presented in this paper is capable of hovering at any attitude provided that thrust is sufficiently large. A geometric controller is also developed on the special Euclidean group to track given desired position and attitude trajectories under the effects of unknown disturbances. These are particularly useful for ground tests for large angle rotational dynamics of spacecraft that are combined with arbitrary translational motions. A numerical example that involves a nontrivial maneuver and preliminary experimental tests are also presented.