  Unmanned aerial vehicles (UAVs) are reaching offshore. In this work, we
formulate the novel problem of a marine locomotive quadrotor UAV, which
manipulates the surge velocity of a floating buoy by means of a cable. The
proposed robotic system can have a variety of novel applications for UAVs where
their high speed and maneuverability, as well as their ease of deployment and
wide field of vision, give them a superior advantage. In addition, the major
limitation of limited flight time of quadrotor UAVs is typically addressed
through an umbilical power cable, which naturally integrates with the proposed
system. A detailed high-fidelity dynamic model is presented for the buoy, UAV,
and water environment. In addition, a stable control system design is proposed
to manipulate the surge velocity of the buoy within certain constraints that
keep the buoy in contact with the water surface. Polar coordinates are used in
the controller design process since they outperform traditional Cartesian-based
velocity controllers when it comes to ensuring correlated effects on the
tracking performance, where each control channel independently affects one
control parameter. The system model and controller design are validated in
numerical simulation under different wave scenarios.
