Robotic Technology Development a "Fuel-Filling" Endeavor

  • Published
  • By Heyward Burnett
  • Materials & Manufacturing
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  Air Force Research Laboratory materials experts are exploiting robotics technology to create a capability that will significantly improve the safety of personnel engaged in aircraft ground refueling activities. While ground refueling equipment has improved 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. 

AFRL started developing this automated system for F-35 Joint Strike Fighter ground refueling at the request of Air Education and Training Command, the Air Force Petroleum Agency, and Naval Air Systems Command. This effort, which satisfies Air Force Smart Operations for the 21st Century nitiatives for innovative, efficient use of materiel and personnel, will ultimately provide the Automated Aircraft Ground Refueling system as a feasible, quick, and safe alternative to manual refueling of aircraft. In addition, future advances made in this area may one day permit refueling crews working in closed environments to operate free of protective gear and still be shielded from chemical-biological risks. 

Once fully functional, the 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 AAGR concept has undergone evaluation in the laboratory. Specifically, researchers conducted a demonstration using a vision-guided robot to move a refueling nozzle to an aircraft mock-up, locate the SPR adapter, and place a refueling nozzle on the adapter. For the demonstration effort, they fitted a robotic arm with a charge-coupled-device camera and a simulated SPR nozzle. A personal computer (aided by a mainframe computer) processed image files received from the robot and used these images to guide the robot towards the SPR adapter. The robot slid the simulated nozzle around the adapter and rotated the nozzle. Encompassing several successful iterations of this process, the demonstration helped to prove the viable use of an autonomous robot as an alternative to manual refueling. With a plan to start demonstration test early in 2010, researchers are currently making technology selections, evaluating robotic vision equipment, identifying the utilities required at the demonstration site, and preparing to build the system.