A researcher from the University of Sydney believes he’s solved the limited endurance levels of unmanned aerial vehicles (UAV) with a new method for autonomously docking drones for refueling or recharging purposes, whilst both aircraft remain in flight.
Daniel Wilson, who conducted the work as part of his PhD research, explains:
“At the moment, a UAV's range and endurance is constrained by the amount of fuel that can be stored on board. As you add more fuel, the weight of the aircraft increases, which means more fuel must be consumed to stay aloft.”
Daniel used a combination of exact measurements from an infrared camera, with GPS and inertial sensors, to facilitate the aerial docking.
“Aerial refueling has been used with manned aircraft, but to the best of our knowledge, UAV airborne docking had not been demonstrated prior until our experiments late last year. The biggest challenge is the highly accurate and reliable relative positioning performance to allow a second aircraft to dock with a small target, in the air, and amidst turbulence,” states Daniel.
He adds: “This type of technology is useful in situations where greatly extended persistence over an area is desirable, such as the search for the MH370. It would allow aircraft to use their fuel to search the target area, rather than flying back and forth from land. It could also be used to keep high-flying UAVs airborne, in place of satellites for communication.”
To meet the engineering challenges that come with this new technology, Daniel has developed an autopilot and rapid software development process, a solution, worth noting, that has twice won him the International Simulink Design Challenge.
Now that he’s successfully demonstrated his technological solution, he has publicly explained the principle behind his aerial docking design:
“There are two autonomous aircraft, a leader and a follower. The leader tows a cone-shaped, parachute-like drogue. The objective is for the follower to autonomously dock its nose, within the drogue.”
“Initially both the aircraft rendezvous to a formation position where the follower's infrared camera can observe infrared LED markers on the leader's wingtips and tail.”
“Once docked, the follower is commanded to station for a certain amount of time to simulate refueling or recharging. The follower disconnects and resumes its mission.”
“In addition to docking, this system could be used for any application that requires highly accurate positioning, relative to a static or moving target. This could include, precision landing on ships, net recovery or close formation flight,” says Daniel.
Sound a bit confusing? Check out Daniel’s latest airborne docking flight test results via the clip below:
The full study, results and all, will be described in his PhD thesis “Guidance, Navigation and Control for UAV Close Formation Flight and Airborne Docking”, which is scheduled to publish later this year.
Via the University of Sydney
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