by John McHale
Rockwell Collins and the Defense Advanced Research Projects Agency (DARPA) conducted several flight tests of an unmanned F/A-18 subscale model air vehicle while increasing levels of damage on the aircraft. As part of the same DARPA effort Rockwell Collins also had an unmanned aerial vehicle (UAV) fly aerobatics with position tracking. The results were discussed during a news briefing at AUVSI's Unmanned Systems North America 2010 exhibition in Denver.
One of the flight tests involved ejecting 60 percent of the right wing, 30 percent of the right fin rudder, and 30 percent of the right stabilizer. Despite the damage, the UAV remained steady in-flight and was able to land. Another flight test demonstrated the ability for the aircraft to continue to fly a fixed trajectory and land safely after the engine was turned off.
The last test involved blowing up about 80 percent of the UAV's right wing after which the aircraft landed safely, says David Vos senior director of Rockwell Collins Control Technologies and Unmanned Aircraft Systems. Once on the ground the aircraft was on the ground it still fought to maintain its equilibrium.
The trajectory is stabilized in a fraction of second, enabling the UAV to stay on its mission -- which in this case is to fly a particular trajectory and land safely, Vos says.
All flight tests included auto take off and landing.
Vos says the next step will be to port the technology onto an operational UAV. He declined to say which UAV, only that the reporters in the room would recognize it.
"This latest flight test campaign is an important step toward our ultimate goal of offering our damage tolerance control software to the UAV market," Vos says. "Our solution improves the survivability of UAVs in theater, while simultaneously improving the reliability of UAVs flying in civilian airspace. By detecting and instantly and automatically compensating for failure or damage in flight, UAVs and manned aircraft can soon achieve coexistence."
Damage tolerance is an enabling capability for increasing the mission reliability of UAVs operating in hazardous and high-threat environments, according to Rockwell Collins. The technology provides for real-time autonomous accommodation of damage, followed by an adaptation process that alters the flight control system to compensate for the effects of the damage.
Emergency management of UAVs is a big concern of the Federal Aviation Administration this test is a big step in improving the reliability of UAVs when somethign goes wrong during flight, Vos says.
Vos says he believes that the damage tolerance technology for UAVs will be transferred into manned commercial aircraft one day. He says he has a dream that at some point planes will be pilot optional -- in other words if the pilot doesn't feel like flying he doesn't have to, the autonomous controls will handle everything -- including emergencies. "Before I'm in the ground I want to be able to get in the cockpit flying to see my mother-in-law, and decide that I don't feel like piloting, so I will read the paper instead and enjoy a cup of coffee."
Other maneuvers demonstrating failure and immediate automatic recovery through damage tolerance controls that were conducted during flight tests include: locking the right aileron in neutral position in-line with the rest of the airplane, which caused an uncontrolled roll and an engine idle test where engine command is idle, which means there is no throttle up or down.
During other flight tests DARPA and Rockwell Collins demonstrated the first UAV to fly aerobatics with position tracking. This demonstration is part of the third phase of a damage tolerance contract awarded to Rockwell Collins.
Vos says the technology is now set to be ported to an operational UAV. He indicated that while others have flown aerobatics of autonomous UAVs, the most recent DARPA test was the first UAV to fly aerobatics with position tracking with a fixed aerobatic trajectory in space.
"This all-attitude control technology supplies UAVs with damage tolerance and the ability to fight -- through evasive maneuvers -- and to counter threats such as missiles," Vos says. "This technology will also enable UAVs to fly at low altitude, in urban environments and even in confined places such as inside buildings and caves."