If Birds Can Perch, Why Can't Drones?

Designing drones that can land and perch anywhere would be really useful, but it's harder than it may sound. Learn how researchers have pulled it off in this episode of BrainStuff, based on this article: https://science.howstuffworks.com/perchiing-drones-news.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff, a production of I Heart Radio,
Hey brain Stuff, Lauren Vogel bomb here. But when it
comes to accomplishing deft aerobatic maneuvers, aerial drones still aren't
as good as birds and other flying animals, though engineers
are working on it, and they're also working on another

(00:22):
avian feet of agility, the ability to land and perch
on just about any object or surface, ranging from tree
branches to telephone wires without falling off. This is perhaps
more complicated than it sounds. A gripping random surfaces is
easy for many birds and other animals, including many humans,

(00:42):
but it's difficult for robots. Think about how you grip,
say a door handle or a coffee cup. You have
to figure out where the object is and how wide
to open your hand, and how to close your hand
around it, and how tightly to close your hand without
breaking the handleboard, the cup or breaking your hand for
that matter. It's not easy for all humans. Now imagine

(01:05):
you were trying to balance on that object that you're gripping.
But researchers at Stanford University have developed a device called
a stereotyped Nature inspired Aerial grasper or SNAG for short
that can be attached to a quad copter drone to
give it feet and legs resembling those of a falcon.
When equipped with the device, the drone is able to

(01:28):
not just fly around, but catch and carry objects and
then perch on various surfaces. Of course, a duplicating the
agility of birds wasn't easy to do. The researchers shot
video of small parrots flying back and forth between special
perches that contained sensors to measure the physical forces of landing, perching,
and take off. One of the researchers, William Roderick, explained

(01:52):
in the Stanford News release in December. What surprised us
was that the birds did the same aerial maneuvers no
matter what surface as they were landing on. They let
the feet handle the variability and complexity of the surface
texture itself. Giving a drone similar abilities required technological ingenuity.

(02:13):
A snag has a three D printed structure that emulates
a falcon's lightweight bones, and each of its legs is
equipped with one motor for moving back and forth and
a second one for grasping mechanisms in the robots legs
are designed to absorb impact energy and passively convert it
into grasping force the way that a bird's tendons would.

(02:33):
As a result, a drone equipped with the device can
clutch something strongly in just twenty milliseconds. Once the robot's
feet are wrapped around a perch, its ankles lock, and
an accelerometer device that measures changes in motion detects the
landing and triggers a balancing algorithm to stabilize it on
the perch elsewhere. Researchers at other institutions have also been

(02:56):
working for years on giving drones the ability to land
and hang onto something. For example, in researchers at Northeastern
University unveiled a technology that allows a flying drone to
hang upside down like a bat. Being able to land
in various places helps drones to conserve energy that they
would expend by having to remain airborne. That's really useful

(03:20):
because the flight time of robotic aircraft is limited by
their battery power, and their battery power is in turn
limited by the weight that the aircraft can carry. Today's
episode is based on the article Robotic drones can now fly,
stop and perch just like birds on how Stuff Works
dot Com, written by Patrick J. Tiger brain Stuff is

(03:42):
production of I heart Radio in partnership with how stuff
works dot Com, and it's produced by Tyler Klang. Four
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