Positioned alongside a stationary platform, under simulated sea conditions, the USV Sea Fox receives fuel from a robotic fluids transfer arm via magnetic refueling fitting (shown here mounted in the forward bow section of the vessel). Photo: U.S. Naval Research Laboratory |
Engineers from the NRL Spacecraft Engineering Department
(SED) successfully demonstrated the robotic fluids transfer from a stationary
platform to an unmanned surface vehicle (USV) in wave heights greater than 3 ft.
The Rapid Autonomous Fuel Transfer (RAFT) project exhibits the ability to track
the motion of a Sea Fox naval vessel, safely emplace a magnetic refueling
fitting to an on-board refueling receptacle, and successfully complete fluids
transfer.
Under current circumstance, USV refueling demands that a
grappled connection, usually by hand, be made between the USV and the refueling
vessel.
“Refueling a USV at sea, particularly in adverse
weather or in high sea states, can prove difficult and often dangerous,”
said Glen Henshaw, PhD, Attitude Control Section, SED Control Systems Branch.
“Transferring our extensive knowledge and proven success of robotic
spacecraft servicing can prove equally successful in reducing risks at
sea.”
Providing the host ship the capability to refuel USVs
without the need to bring them aboard ship enhances mission efficiency and reduces
host ship exposure. This works to improve the effectiveness of naval USV
missions and decrease risks to personnel and potential damage to vessels and
equipment.
Experimenting with both fully autonomous and
human-controlled operations at the U.S. Army Aberdeen Test Center wave
simulator facility, NRL engineers completed approximately 60 trial refueling
attempts at sea states ranging from zero, or calm seas, to 3.25, or maximum
wave heights in excess of three feet, with a demonstrated high rate of success.
Funded by the Defense Advanced Research Projects Agency
(DARPA), the Rapid Autonomous Fuel Transfer (RAFT) project teamed NRL with Clemson
University, Science Applications International Corporation (SAIC) and Space and
Naval Warfare Systems Command (SPAWAR). NRL was the lead robotics integrator
and designed the robotics system.
Further robotic transfer tests will possibly include
land-based autonomous HMMV (high-mobility multipurpose wheeled vehicle)
applications without the need to stop driving and on-air unmanned aerial vehicle
(UAV) refueling.
The USV Sea Fox was developed for Navy missions to provide
force protection with more flexibility in Enhanced Maritime Interdiction
Operations and safer Intelligence, Surveillance and Reconnaissance (ISR)
gathering to aid in threat assessment, decision-making, and situational
awareness, prior to escalation to lethal actions.