Flexible Robo-Legs Could Help Helicopters Stick Tricky Landings
Foldable robotic legs could help helicopters land on uneven surfaces.
Credit: DARPA

Helicopters of the future could use insectlike robotic legs to land in unlikely places — like the slopes of steep hills or the decks of rocking boats.

Touching down on uneven surfaces is something that today's helicopters are just not equipped to do, according to the Defense Advanced Projects Agency, or DARPA, the branch of the U.S. Department of Defense that dreams up new military technologies. But robotic landing gear developed for DARPA at the Georgia Institute of Technology (Georgia Tech) could better equip these aircraft to land just about anywhere.

The new landing gear features four robotic legs with bendable "knees" that turn a normal helicopter into what looks like a giant, mechanical fly. When the chopper touches down, the legs automatically move to stabilize the aircraft, according to DARPA officials, who recently tested out the new system near the Georgia Tech campus in Atlanta. [Humanoid Robots to Flying Cars: 10 Coolest DARPA Projects]

"The equipment — mounted on an otherwise unmodified, unmanned helicopter — successfully demonstrated the ability to land and take off from terrain that would be impossible to operate from with standard landing gear," Ashish Bagai, DARPA program manager, said in a statement.

Embedded with force-sensitive contact sensors on each of its feet, the robotic legs determine the precise angle they need to assume to keep the helicopter from tipping over when it lands on uneven ground, such as on the side of a hill or mountain. The legs can also keep the chopper steady if it lands on a moving surface, such as the deck of a rocking ship at sea.

The robotic system is very different from what Bagai referred to as "standard landing gear," which typically features either retractable wheels or fixed skids (the ski-type beams sometimes seen under the fuselage of a helicopter). Neither of these options works well on uneven terrain, which is unfortunate, because helicopters often need to land and take off in areas like disaster zones, where there may not be any flat surfaces, according to DARPA.

The robo-insect landing gear can handle landings on irregular terrain, even if there are significant obstacles in the way, including rocky ledges or boulders. And besides making landings more versatile, the jointed legs also significantly reduce the damage inflicted on helicopters during "hard landings," according to DARPA. The agency said these improved capabilities can "greatly expand" the effectiveness of helicopters used for both military and nonmilitary purposes.

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