Tech Briefs Magazine - August 2023 - 36

Robotics & Automation
as consoles, keyboards, touchscreens,
and hand-gesture recognition redundant, "
said Professor Iacopi.
" By using cutting edge graphene material,
combined with silicon, we were able
to overcome issues of corrosion, durability,
and skin contact resistance, to develop
the wearable dry sensors, " she said.
A new study outlining the technology
has just been published in the peer-reviewed
journal ACS Applied Nano Materials.
It shows that the graphene sensors
developed at UTS are very conductive,
easy to use and robust.
The hexagon patterned sensors are
positioned over the back of the scalp, to
detect brainwaves from the visual cortex.
The sensors are resilient to harsh conditions
so they can be used in extreme operating
environments.
The user wears a head-mounted augmented
reality lens which displays white
flickering squares. By concentrating on
a particular square, the brainwaves of
the operator are picked up by the biosensor,
and a decoder translates the signal
into commands.
The technology was recently demonstrated
by the Australian Army, where
soldiers operated a Ghost Robotics quadruped
robot using the brain-machine interface.
The device allowed hands-free
command of the robotic dog with up to
94 percent accuracy.
" Our technology can issue at least
nine commands in two seconds. This
means we have nine different kinds of
commands and the operator can select
one from those nine within that time
period, " Professor Lin said. " We have
also explored how to minimize noise
from the body and environment to get
a clearer signal from an operator's
brain, " he added.
The researchers believe the technology
will be of interest to the scientific
community, industry, and government,
and hope to continue making advances
in brain-computer interface systems.
For more information, contact
newsroom@uts.edu.au; +61 295-14-1623.
Caterpillar-Inspired Soft Robotics Locomotion
The caterpillar-bot's movement is driven by a novel pattern of silver nanowires that use heat
to control the way the robot bends.
North Carolina State University, Raleigh, NC
R
esearchers at North Carolina State University
have demonstrated a caterpillar-like
soft robot that can move forward,
backward, and even dip under narrow
spaces. The caterpillar-bot's movement is
driven by a novel pattern of silver nanowires
that use heat to control the way the robot
bends.
" A caterpillar's movement is controlled
by local curvature of its body -
its body curves differently when it pulls
itself forward than it does when it pushes
itself backward, " said NC State's Yong
Zhu. " We've drawn inspiration from the
caterpillar's biomechanics to mimic that
local curvature, and use nanowire heaters
to control similar curvature and
movement in the caterpillar-bot.
" Engineering soft robots that can
move in two different directions is a significant
challenge in soft robotics, " Zhu
added. " The embedded nanowire heaters
allow us to control the movement of
the robot in two ways. We can control
which sections of the robot bend by controlling
the pattern of heating in the soft
robot. And we can control the extent to
which those sections bend by controlling
the amount of heat being applied. "
The caterpillar-bot consists of two layers
of polymer, which respond differently
when exposed to heat. The bottom layer
contracts when exposed to heat; the top
layer expands when exposed to heat. A pattern
of silver nanowires is embedded in the
expanding layer of polymer. The pattern
includes multiple lead points where researchers
can apply an electric current.
The researchers can control which sections
of the nanowire pattern heat up by applying
an electric current to different lead
points, and can control the amount of heat
by applying more or less current.
" We demonstrated that the caterpillar-bot
is capable of pulling itself forward
and pushing itself backward, " said NC
State's Shuang Wu. " In general, the more
current we applied, the faster it would
move in either direction. However, we
found that there was an optimal cycle,
which gave the polymer time to cool - effectively
allowing the 'muscle' to relax before
contracting again. If we tried to cycle
the caterpillar-bot too quickly, the body did
not have time to 'relax' before contracting
again, which impaired its movement. "
They also demonstrated that the caterpillar-bot's
movement could be controlled
to the point where users were
able steer it under a very low gap. In essence,
the researchers could control
both forward and backward motion as
well as how high the robot bent upward
at any point in that process.
The caterpillar-bot consists of two layers of polymer, which respond differently when exposed to
heat. The bottom layer contracts when exposed to heat and the top layer expands when exposed
to heat. (Image: Shuang Wu, NC State University)
36
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" This approach to driving motion in
a soft robot is highly energy efficient,
and we're interested in exploring ways
that we could make this process even
more efficient, " said Zhu. " Additional
next steps include integrating this approach
to soft robot locomotion with
sensors or other technologies for use in
various applications - such as searchand-rescue
devices. "
For more information, contact Matt
Shipman at matt_shipman@ncsu.edu.
Tech Briefs, August 2023

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Tech Briefs Magazine - August 2023

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