World's smallest untethered flying robot takes off

Researchers at the University of California, Berkeley, have developed the world’s smallest untethered controllable flying robot, a 21-milligram, 9.4-millimeter device powered by a magnetic field. The machine can lift off, hover, steer, and recover from collisions without onboard power or sensors, opening new possibilities for medical, industrial, and environmental applications.

Read the full article at https://www.paperleap.com/blog/articles/world-s-smallest-untethered-flying-robot-takes-off-0cccc3

Episode Transcript

Speaker 1 (00:00):
Welcome to the paper Leap podcast, where a science takes
the mic. Each episode, we discuss cutting edge research, groundbreaking discoveries,
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(00:21):
Don't forget to subscribe so you never miss an insight.
All the content is also available on paper leap dot com. Okay, ready,
let's start. Imagine a flying robot so small it could
perch on your fingernail and then take off again without
any wires or batteries. That's exactly what a team at

(00:44):
the University of California, Berkeley has just made real. In
a paper published in Science Advances, Fan Bing Sui Wei,
Yui Kamar Burhussi, Yuan Gao, Mark Mueller, and Leeway Lynn
unveiled the world smallest and lightest, untethered, controllable flying robot,

(01:05):
a twenty one milligram nine point four millimeter wide rotating
wing machine powered entirely by a medietic field, and it
can do more than just lift off. It can hover, turn,
survive collisions, and even recover its balance. Mid air. Miniaturizing

(01:25):
a flying robot is harder than it sounds. As you
make it smaller, every gram matters, and carrying on board
batteries or motors quickly becomes impossible. Many inset size robots
today stay tethered, drawing power through thin wires. This limits
their movement and makes real world expiration impossible. The Berkeley

(01:48):
team sidestep this by using a single axis alternating magnetic
field as an invisible power cord. Tiny permanent magnets embedded
in the robot's body try to align with the field,
creating torque that spins a four blade propeller. This generates
lifts without any onboard power source. To keep the robot stable,

(02:09):
the engineers added a balance ring. This boosts rotational inertia,
creating a gyroscopic effect think spinning top that helps it
maintain its upright position in the air. The UC Berkeley
Flying robots in flight abilities are remarkable given its subcentimeter size.
It can launch straight upward with a steady climb, maintaining

(02:32):
its pitch within just a few degrees of vertical By
carefully tuning the magnetic field's frequency, it can hover in
place for short periods and impressive feet at this scale,
or even tiny air currents, can cause instability. The robot's
design also allows it to survive and recover from mid
air collisions, with more than three quarters of tests ending

(02:56):
in successful stabilization. Rather than a crash. Steering is achieved
without any on board sensors or electronics. Instead, the team
manipulates magnetic field gradients to guide it left or right,
enabling controlled turns during flight. All of these maneuvers rely
on the physics of its spinning gyroscopically stabilized design rather

(03:19):
than complex control systems. For perspective, the smallest untethered flying
robot before this was about twenty eight millimeters wide. That
is three times larger than Berkeley's creation. At just twenty
one milligrams, it's lighter than a grain of rice and
far below the one gramd mark that only three untethered

(03:39):
robots have ever crossed. Its lift to power ratio is
among the highest in its class, point zero seven to
two newtons per watt, thanks to the absence of heavy
onboard power storage and an efficient aerodynamic shape. This isn't
just about breaking size records. Subst dentimeter flying robots like

(04:01):
UC Berkeley's twenty one milligram prototype could open doors to
tasks that are currently impractical or impossible for larger drones.
In medicine, they could navigate inside the human body to
perform minimally invasive diagnostics or delivered targeted treatments. In industry,
they could slip through narrow pipes, turbines, or other confined

(04:24):
mechanical spaces to inspect for damage without the need for
costly disassembly. In disaster zones, their tiny side would let
them weave through rubble to locate trapped survivors. And in
environmental science, they could quietly monitor insects, pollination, or microclimate
without disturbing the natural balance. By combining their small size,

(04:49):
wireless power system, and controllable flight, these robots could operate
in environments that demands both delicacy and precision. Nature still
holds the crown in the tiny flight arena. A parasitic
wasp called Newsonia vitripennis has a three millimeter wingspan and
weighs just zero point five to eight milligrams. But inch

(05:13):
by inch, or rather millimeter by millimeter, robotics is catching up.
What makes this breakthrough exciting isn't only the engineering elegance,
but the fact that it opens a path to useful autonomous,
insect scale robots without the bulk and complexity of conventional drones.

(05:33):
Sometimes moving forward in technology means thinking small, in this case,
very small, and in that space between biology and engineering,
the future of flight might just be the size of
a sesame seed. That's it for this episode of the
paperlely podcast. If you found it thought provoking, fascinating, or

(05:57):
just informative, share it with a fellow science neur. For
more research highlights and full articles, visit paperleef dot com.
Also make sure to subscribe to the podcast. We've got
plenty more discoveries to unpack. Until next time, Keep questioning,
keep learning,