Lab Demonstrates Robotic Ground Refueling of Aircraft Published Oct. 14, 2010 By Heyward Burnette Materials and Manufacturing WRIGHT-PATTERSON AIR FORCE BASE, Ohio -- Air Force Research Laboratory engineers successfully demonstrated a prototype of the lab-developed Automated Aircraft Ground Refueling system, which leverages robotics technology and, in turn, significantly improves the safety of personnel engaged in aircraft ground refueling activities. Though ground refueling equipment has advanced over time, the operation itself remains largely unchanged. It is still a manual process that involves physical handling of the fuel supply hose, including its attachment and detachment. Further compounding the risks inherent to this close-in activity is the routine practice of hot-pit refueling, wherein one or more engines continue to run throughout the operation. The introduction of robotic automation will dramatically decrease the potential hazards, since the technology requires fewer people near the aircraft. A fully functional AAGR system will enable an operator to initiate refueling with the push of a button on an Operational Control Unit several hundred feet away from the aircraft. The OCU will communicate with a computer configured to govern the actions of the robot, which is itself tethered to a fuel hydrant by a pantograph. This multijointed, moving pipeline follows behind the robot and supplies it with fuel. A vision-based guidance system will direct the robot's movements, with vision and proximity sensors observing the aircraft's location and the robot's path of approach. After this guidance system confirms aircraft type, orientation, and fuel door location, the robot will move to position itself near the fuel door. Accurate angular measurements guide the robot in aligning the fuel nozzle with the aircraft's single-point refueling adapter. After the robot has attached the nozzle and completed the refueling task, a similar, reverse procedure will detach and retract the robot from the aircraft. Throughout the process, the guidance sensors will continue to monitor the scene, registering unexpected changes in the robot's proximity to the aircraft or other objects in order to prevent unwanted contact. The OCU operators will be able to supervise the simultaneous activity of multiple robots, relying on a built-in abort function to quickly halt operations should a problem arise. The successfully validated prototype robot has a manipulator arm mounted on a low-profile, wheel-drive platform/vehicle. A 30 ft metal truss connects the vehicle to a pivot point on the ground. As the experiment started, the vehicle drove to the F-35 maintenance interface panel mock-up, following a 90° arc on the ground. The robot used a camera and a laser range finder to determine the panel's orientation, as well as to reorient itself accordingly. After a specially designed tool opened the panel door, a separate arm held the door open while the robot switched to a second tool with a commercial fuel nozzle. The robot then attached the fuel nozzle to the SPR adapter located inside the panel. The nozzle's operating lever/shaft rotated to push the poppet valve and open the flow path. After a pause to simulate fuel flow, the system reversed the steps until the door closed and latched. Based upon the successful outcome of this important demonstration, the team will begin adding functionality pertaining to electrical bonding, fuel status light checks, and software compatibility with Joint Architecture for Unmanned Systems technology. Pending these upgrades, the AAGR system will be ready for field-test preparation.