[Editors] MIT's intelligent aircraft fly, cooperate autonomously

[Elizabeth Thomson]

MIT News Office
Massachusetts Institute of Technology
Room 11-400
77 Massachusetts Avenue
Cambridge, MA  02139-4307
Phone: 617-253-2700
http://web.mit.edu/newsoffice/www

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MIT's intelligent aircraft fly, cooperate autonomously
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For Immediate Release
TUESDAY, SEP. 26, 2006
Contact: Elizabeth A. Thomson, MIT News Office
Phone: 617-258-5402
Email: thomson at mit.edu

IMAGES AVAILABLE

CAMBRIDGE, Mass.--The U.S. military depends on small, unmanned aerial 
vehicles (UAVs) to perform such tasks as serving as  "eyes in the 
sky" for battalion commanders planning maneuvers. While some of these 
UAVs can be easily carried in a backpack and launched by hand, they 
typically require a team of trained operators on the ground, and they 
perform only short-term tasks individually rather than sustained 
missions in coordinated groups.

MIT researchers, in collaboration with Boeing's advanced research and 
development arm, Phantom Works, are working to change that.

They have developed a multiple-UAV test platform that could lay the 
groundwork for an intelligent airborne fleet that requires little 
human supervision, covers a wide area, and automatically maintains 
the "health" of its vehicles (for example, vehicles anticipate when 
they need refueling, and new  vehicles launch to replace lost, 
damaged, or grounded ones).

Aeronautics and Astronautics Professor Jonathan How, who heads the 
research team, believes it is the first platform to publicly 
demonstrate sustained, coordinated, autonomous flight with multiple 
UAVs.

At the Boeing Tech Expo at Hanscom Air Force Base in May, students on 
the team conducted more than 60 flights on demand with two UAVs. In 
the MIT Aerospace Controls Laboratory, the research team regularly 
conducts flights using three to five UAVs, which have achieved 
complex tasks such as persistent surveillance of a defined area.

According to John Vian, a technical fellow at Phantom Works who 
collaborates with the MIT team, "They have demonstrated quite 
successfully that UAV swarms can achieve high functional reliability 
by incorporating advanced health monitoring and adaptive control 
technology." Simply put, adaptive control addresses the fact that the 
parameters of the system being controlled are uncertain or vary 
slowly over time.

A fleet of UAVs could one day help the U.S. military and security 
agencies in difficult, often dangerous, missions such as 
round-the-clock surveillance, search-and-rescue operations, sniper 
detection, convoy protection and border patrol. The UAVs could also 
function as a mobile communication or sensor network, with each 
vehicle acting as a node in the network.

Such missions depend on "keeping vehicles in the air. The focus of 
this project is on persistence," said How. Persistence requires 
self-sufficiency. "You don't want 40 people on the ground operating 
10 vehicles. The ultimate goal is to avoid a flight operator 
altogether."

The test platform consists of five miniature "quadrotor" aircraft - 
helicopters with four whirling blades instead of one - each a little 
smaller than a seagull. It also includes an indoor positioning 
system, as well as several miniature autonomous ground vehicles that 
the UAVs can track from the air.

Each UAV is networked with a PC. The setup allows a single operator 
to command the entire system, flying multiple UAVs simultaneously. 
Moreover, it requires no piloting skills; software flies the vehicles 
from takeoff to landing.

The vehicles in MIT's test platform are inexpensive, off-the-shelf 
gadgets; they can be easily repaired or replaced with a new vehicle, 
just as might happen in a real-world scenario involving numerous 
small UAVs on a long-term mission. The researchers can thus 
experiment constantly without concern for mishaps with expensive 
equipment.

"In this project, the larger system is what does the useful thing; 
the vehicle becomes just a cog in the wheel," said Mario Valenti, a 
Ph.D. candidate in electrical engineering and computer science (EECS) 
who works on the project with Brett Bethke, a Ph.D. candidate in 
aeronautics and astronautics, and Daniel Dale, a M.Eng. candidate in 
EECS.

Valenti, Bethke, Dale and colleagues operate the platform as often as 
possible, trying out different tasks, testing the system's response 
to sudden changes in mission (such as the appearance of new targets 
or the loss of a UAV) and coordinating with the autonomous ground 
vehicles. The laboratory provides a dynamic, real-time environment - 
a room with walls, furniture, equipment and other obstacles. The 
researchers analyze the performance of the test platform over time, 
using the resulting information to maximize the control system's 
ability to anticipate and recover from system failures.

The team has also designed an automatic docking station that allows 
the UAVs to recharge their batteries when they are running low. When 
the aircraft finish "refueling," they can then return to assist in 
ongoing flight operations.

In addition, the team recently achieved a milestone in autonomous 
flight: landing on a moving surface. Using "monocular vision," one of 
the quadrotors successfully landed on a moving vehicle - a 
remote-controlled lab cart. A video camera fastened to the UAV uses a 
visual "target" to determine in real time the vehicle's distance 
relative to the landing platform. The ground station then uses this 
information to compute commands that allow the UAV to land on the 
moving platform. This technology could enable UAVs to land on ships 
at sea or on Humvees moving across terrain.

Other contributors to the project include Professor Daniela Pucci de 
Farias of mechanical engineering; Glenn Tournier, MIT S.M. 2006; and 
Professor Eric Feron of the Georgia Institute of Technology. The work 
is sponsored by Boeing Phantom Works in Seattle.

Videos and more information about the project can be found at: 
"http://vertol.mit.edu/" vertol.mit.edu/.

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Story by Lauren Clark, MIT School of Engineering