Robots that Land and Cling on Vertical Surfaces

Vision for Perching UAV
A flock of small, unmanned air vehicles flies quietly into a city, maneuvering among the buildings. They communicate as they search for places to land, not on streets or flat rooftops but on the sides of buildings and under the eaves, where they can cling, bat or insect-like, in safety and obscurity. Upon identifying landing sites, each flier turns toward a wall, executes an intentional stall and, as it begins to fall, attaches itself using feet equipped with miniature spines that engage small asperities on the surface. Using its propeller in combination with its limbs, the flier can creep along the wall and reorient for a better view. With opposed pairs of spines, the flier clings tenaciously to resist gusts of wind and ride out inclement weather. The fliers stay attached for hours or days, consuming little power and emitting no sound as they monitor the area. When finished, they launch themselves with a jump and become airborne again, ready for their next mission.

One avian concept that designers are trying to emulate is the ability to perch. A manned aircraft cannot settle into a tree for observation, but a small UAV might be able to imitate birds by landing on a branch. “The concept of perching, as an engineering challenge for what an airplane can do, will be quite a feat,” Ol warrants.

The AFRL may team with industry and academia in its research, Ol states. The laboratory has not teamed with anyone yet, but it is keeping an eye on other organized activities. One company, Aerovironment, already has built two different micro-UAVs that weigh less than one pound.

The laboratory is keeping potential dual-use systems on its radar, Ol adds. For example, its perching UAVs might serve civil authorities in fighting forest fires over vast areas. A fleet of UAVs could perform coordinated patrols that send alarms when fires are detected.