Tech Briefs Magazine - December 2021 - MD-17

magnetic touch sensors at the front
and back, allowing the robots to connect
to one another. Four flexible legs
reduced the need for additional sensors
and parts and gave the robots a level
of mechanical intelligence that helped
when interacting with rough or uneven
terrain.
After printing each robot, they were
built and tested over grass, mulch,
leaves, and acorns. Flat-ground experiments
were conducted over particle
board, and stairs were built using insulation
foam. The robots were also
tested over shag carpeting and rectangular
wooden blocks were glued to
particle board to serve as rough terrain.
When an individual unit became stuck,
a signal was sent to additional robots
that linked together to provide support
to successfully traverse obstacles while
working collectively.
The work will inform the design of
low-cost legged swarms that can adapt
to unforeseen situations and perform
real-world cooperative tasks such as
search-and-rescue operations, collective
object transport, space exploration,
and environmental monitoring. The
research will focus on improving the
Multi-legged swarm robots capable of maneuvering in challenging environments and collectively accomplishing
difficult tasks mimic their natural-world counterparts. (Notre Dame University)
control, sensing, and power capabilities
of the system, which are essential
for real-world locomotion and problem-solving.
For
functional swarm systems, the battery
technology needs to be improved.
Small batteries are needed that can provide
more power, ideally lasting more
than 10 hours. Otherwise, using this
type of system in the real world isn't sustainable.
Additional limitations include
the need for more sensors and more
powerful motors while keeping the size
of the robots small.
For more information, contact Jessica
Sieff at jsieff@nd.edu; 574-631-3933.
Self-Propelled Nanorobots
The " nanoswimmers " could be used to remediate contaminated soil, improve water filtration, or
even deliver drugs to targeted areas of the body.
University of Colorado, Boulder
R
esearchers have
called
discovered
can
that
minuscule, self-propelled particles
" nanoswimmers "
escape
from mazes as much as 20 times faster
than other passive particles. The tiny
synthetic nanorobots are incredibly effective
at escaping cavities within mazelike
environments.
The nanoswimmers came to the attention
of the theoretical physics community
about 20 years ago and people
imagined a wealth of real-world applications.
Unfortunately, these tangible
applications have not yet been realized,
in part because it's been quite difficult
to observe and model their movement
in relevant environments until now.
These nanoswimmers, also called
Janus particles, are tiny spherical particles
composed of polymer or silica,
Motion Design, December 2021
MD Tech Briefs 1221_1.indd 17
engineered with different chemical
properties on each side of the sphere.
One hemisphere promotes chemical
reactions to occur but not the other.
This creates a chemical field that allows
the particle to take energy from
the environment and convert it into
directional motion,
also known as
self-propulsion.
In contrast, passive particles
that
move about randomly (a kind of motion
known as Brownian motion) are known
as Brownian particles. The researchers
converted these passive Brownian particles
into Janus particles (nanoswimmers)
for this research. Then they
made these self-propelled nanoswimmers
try to move through a maze made
of a porous medium and compared
how efficiently and effectively they
found escape routes compared to the
passive, Brownian particles.
The Janus particles were effective
at escaping cavities within the maze
- as much as 20 times faster than
the Brownian particles - because they
moved strategically along the cavity
walls searching for holes, which allowed
them to find the exits very quickly.
Their self-propulsion also appeared to
give them a boost of energy needed to
pass through the exit holes within the
maze.
While
small - about 250 nanometers or just
wider than a human hair (160 nanometers)
but still much smaller than the
head of a pin (1-2 millimeters) - the
work is scalable. This means that these
particles could navigate and permeate
17
the particles are incredibly
Cov
ToC
11/17/21 3:41 PM

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Tech Briefs Magazine - December 2021

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