12 December 2013
On 17 February 2011, DARPA announced the development of the first fully functional robotic bird.  The “Nano Hummingbird” or, as it is also less imaginatively called, the “Nano Air Vehicle” (“NAV”), was the successful result of a project started in 2006 by AeroVironment, Inc. under the direction of DARPA.  Robots, by definition, must “do work.” And the Nano-Hummer was the first fully functional bird-drone designed and able to perform surveillance and reconnaissance missions.
This robotic hummingbird can remain aloft for 11 minutes and attain a speed of 11 mph.  With a skeleton of hollow carbon-fiber rods wrapped in fiber mesh, coated in a polyvinyl fluoride film,  and carrying “batteries, motors, and communications systems; as well as the video camera payload,” the robo-hummer weighs just .67 ounces. 
Designed to be deployed in urban environments or on battlefields, this drone is can “perch on windowsills or power lines” and even “enter buildings to observe and its surroundings” while relaying a continuous video back to its “pilot.” [video] 
In terms of appearance, the Nano-Hummer was, and is, quite like a hummingbird. Although larger than the typical hummingbird, Nano-Hummer, is well within the size range of the species and is, actually, smaller than the largest of real hummingbirds.  With a facade both shaped and colored to resemble the real bird, the Nano-Hummer presents the viewer with a remarkable likeness of a hummingbird. 
The Nano-Hummer isn’t stealth in the sense of evading radar. Nor is it “cryptic,” that type of camouflage that blends, or disappears, into the surrounding terrain. Rather, with the appearance of a hummingbird, the designers used a type of camouflage called “mimesis,” also termed “masquerade,” as concealment. A camouflaged object is said to be “masqueraded” when the object can be clearly seen, but looks like something else, which is of no special interest to the observer. And such camouflage is important to a mini-drone with the primary purpose of surveillance and reconnaissance. 
Designing this drone on the “hummingbird model,” however, was not done only for the purpose of camouflage. The project’s objective included biomimicry, that is, biologically inspired engineering.  With the hummingbird, its amazingly diverse flight maneuvers were the object of imitation. However, UAV’s head researcher, Matt Keennon, admits that a perfect replica of what “nature has done” was too daunting.  For example, the Nano-Hummer only beats its wings 20 times a second, which is slow motion compared to the real hummingbird’s 80 beats per second. [video] 
Whatever the technical shortfalls, this bird-bot replicates much of the real hummingbird’s flight performance.  Not only can it perform rolls and backflips [video] but, most important of all, it can hover like the real thing. [video]  Part of the importance of the ability hover relates to its reconnaissance and surveillance functions. Hovering allows the video camera to select and observe stationary targets. However, the “hover” of both hummingbirds and bees attracts so much attention from developers of drone technology because it assures success in the most difficult flight maneuver of all — landing. In fact, landing is the most complex part of flight, and the maneuver most likely to result in accident or disaster.
When landing, a flying object must attain the slowest speed possible before touching down. Hovering resolves the problem neatly by assuring that the robot can stop in midair and, therefore, touch the ground or perch as zero speed. Observe the relatively compact helicopter landing port in contrast to the long landing strip required by an airplane which must maintain forward motion when airborne.
The drone has a remarkable range of movement in flight much like the real hummingbird.  Nano-Hummer “can climb and descend vertically; fly sideways left and right; forward and backward; rotate clockwise and counter-clockwise; and hover in mid-air.”  Both propulsion and altitude control are entirely provided by the drone’s flapping wings. [video] 
This remote controlled mini-drone can be maneuvered by the “pilot” without direct visual observation using the video stream alone.  With its small camera, this drone can relay back video images of its location.  The camera angle is defined by the drone’s pitch. In forward motion, the camera provides a continuous view of the ground. Hovering provides the best camera angle for surveying rooms. [video] 
To DARPA, it was particularly important that this drone demonstrate the ability to hover in a 5 mph side-wind without drift of more than one meter.  The CIA’s “insectothopter,” a robotic dragonfly was developed in the 1970’s. [image]  This unmanned aerial vehicle “was the size of a dragonfly, and was hand-painted to look like one.”  Powered by a small gasoline engine, the insectothopter proved unusable due to its inability to withstand even moderate wind gusts. [video] 
The Nano-Hummingbird was named by Time Magazine as one of the 50 best inventions of 2011  and has paved the way for the development of a whole generation of bird inspired ‘bots, including Prioria’s “Maverick,” [image] [video] and, the even more “bird-like,” Robo-Raven, which is still in development by the Army Research Laboratory. [image 1] [video] [video] Also, the development of this first small bird-bot brought the U.S. Air Force one step closer to one of the goals on its wish list: “flocks of small drones.” 
A flock of small drones sounds really cool – as long as the flock isn’t after me.