  Hybrid unmanned aircraft can significantly increase the potential of micro
air vehicles, because they combine hovering capability with a wing for fast and
efficient forward flight. However, these vehicles are very difficult to
control, because their aerodynamics are hard to model and they are susceptible
to wind gusts. This often leads to composite and complex controllers, with
different modes for hover, transition and forward flight. In this paper, we
propose incremental nonlinear dynamic inversion control for the attitude and
position control. The result is a single, continuous controller, that is able
to track the desired acceleration of the vehicle across the flight envelope.
The proposed controller is implemented on the Cyclone hybrid UAV. Multiple
outdoor experiments are performed, showing that unmodeled forces and moments
are effectively compensated by the incremental control structure. Finally, we
provide a comprehensive procedure for the implementation of the controller on
other types of hybrid UAVs.
