Researchers develop robot for automated aircraft ground refueling

  • Published
  • By Mindy Cooper
  • Materials and Manufacturing Directorate
Researchers with the Air Force Research Laboratory's Materials and Manufacturing Directorate (AFRL/RX) have begun development of an automated aircraft refueling system for the F-35 Joint Strike Fighter. Successful development and testing of the system will provide a feasible alternative to manual refueling of aircraft.

The system will meet the goal of Air Force Smart Operations 21 ─ to find innovative ways to use Air Force materiel and personnel more efficiently. The decreased number of personnel near each aircraft during hot refueling will improve safety. Future advances based on the results of the system will allow refueling crews to operate free of Mission-Oriented Protective Posture gear in a closed environment and still be protected from chemical-biological risks.

"While aircraft ground refueling equipment has improved, the method of refueling has changed minimally. It is still a manual process that involves personnel handling the fuel supply hose, attaching, and then detaching it," Mr. Walt Waltz, the Robotic Group Lead, explained "Sometimes this is done as a "hot-pit refueling," which is refueling while one or more of the engines are operating."

Researchers at the AFRL/RX Airbase Technologies Division at Tyndall Air Force Base, Fla., received a request from the Air Education and Training Command, the Air Force Petroleum Agency and the Naval Air Systems Command to develop an automated system to refuel the F-35 Joint Strike Fighter while on the ground. The Automated Aircraft Ground Refueling (AAGR) system, as it is called, will allow personnel to refuel the aircraft safely, quickly, and efficiently.

Mr. Waltz explained that after considering several options, the researchers have begun developing a robot to meet this challenge. Once completed, an operator will use this robotic system to initiate refueling with the push of a button on an Operational Control Unit (OCU) from several hundred feet away. The OCU will communicate with a computer that will govern the robot's actions. 

The robot will be tethered to a fuel hydrant by a pantograph. This multi-jointed, moving pipeline will follow behind the robot and supply it with fuel. A vision-based guidance system will direct the robot's movements. Vision and proximity sensors will observe the aircraft's location and the robot's approach path. The guidance system will confirm the aircraft type, assess its orientation, and locate the fuel door. The robot will then position itself near the fuel door. Once in position, accurate angular measurements will align the nozzle with the single point refueling (SPR) adapter on the aircraft. The robot will attach the fuel nozzle and begin fueling. At completion, a similar reverse procedure will detach and retract the robot from the aircraft.

Throughout the refueling process, the guidance sensors will monitor unexpected changes in proximity to the aircraft or objects on the ground to prevent unwanted contact. The system's operator will use the OCU to monitor the simultaneous activities of one or more robots. A quick safety abort function will halt the system should a problem arise.

"Earlier this year, the refueling concept was evaluated in the laboratory. A demon-stration was run 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," Mr. Waltz said "A robotic arm was fitted with a charge-coupled device camera and a simulated SPR nozzle. A personal computer aided by a mainframe computer processed image files from the robot and guided it toward the SPR adapter. The robot slid the simulated nozzle around the adapter and rotated the nozzle. The process was demonstrated several times. The system's performance during the demonstration helped to prove that an autonomous robot is a feasible alternative to manual refueling."

The researchers are now making technology selections, evaluating robotic vision equipment, planning for the utilities required at the demonstration site and preparing to build the system. They plan to start demonstrational testing early in 2010.