Tech Briefs Magazine - August 2024 - MD-20

memory polymers to create soft actuators
on a microscale that allow us to control
very small soft robots, which allows
for exceptional control and delicacy. "
The new technique relies on creating
soft robots that consist of two layers. The
first layer is a flexible polymer that is created
using 3D printing technologies and
incorporates a pattern of microfluidic
channels - essentially very small tubes
running through the material. The second
layer is a flexible shape memory
polymer. Altogether, the soft robot is
only 0.8 mm thick.
By pumping fluid into the microfluidic
channels, users create hydraulic
pressure that forces the soft robot to
move and change shape. The pattern
of microfluidic channels controls the
motion and shape change of the soft
robot - whether it bends, twists, or so
on. In addition, the amount of fluid
being introduced, and how quickly it
is introduced, controls how quickly the
soft robot moves and the amount of
force the soft robot exerts.
If users wish to 'freeze' the soft robot's
shape, they can apply moderate heat
(64 °C, or 147 °F), and then let the robot
cool briefly. This prevents the soft robot
from reverting to its original shape, even
after the liquid in the microfluidic channels
is pumped out. If users want to return
the soft robot to its original shape,
they simply apply the heat again after
pumping out the liquid, and the robot
relaxes to its original configuration.
" A key factor here is fine-tuning the
thickness of the shape memory layer
relative to the layer that contains the
microfluidic channels, " said Yinding
Chi, co-lead author of the paper and a
former Ph.D. student at NC State. " You
researchers applied hydraulic pressure,
causing the gripper to pinch closed
on an object. By applying heat, the researchers
were able to fix the gripper in
its " closed " position, even after releasing
pressure from the hydraulic actuator.
The gripper could then be moved -
transporting the object it held - into a
new position. Researchers then applied
heat again, causing the gripper to release
the object it had picked up.
" Because these soft robots are so thin,
we can heat them up to 64 °C quickly
and easily using a small infrared light
source - and they also cool very quickly, "
said Haitao Qing, co-lead author of the
paper and a Ph.D. student at NC State.
" So this entire series of operations only
takes about two minutes.
By pumping fluid into the microfluidic channels,
users create hydraulic pressure that forces the soft
robot to move and change shape. (Image: North
Carolina State University)
need the shape memory layer to be thin
enough to bend when the actuator's
pressure is applied, but thick enough to
get the soft robot to retain its shape even
after the pressure is removed. "
To demonstrate the technique, the researchers
created a soft robot " gripper, "
capable of picking up small objects. The
" And the movement does not have to
be a gripper that pinches, " added Qing.
" We've also demonstrated a gripper that
was inspired by vines in nature. These grippers
quickly wrap around an object and
clasp it tightly, allowing for a secure grip.
" This paper serves as a proof-of-concept
for this new technique, and we're
excited about potential applications for
this class of miniature soft actuators in
small-scale soft robots, shape-shifting
machines, and biomedical engineering. "
For more information, contact Matt
Shipman matt_shipman@ncsu.edu.
A Robot to Aid People with Mild Cognitive Impairment
The tabletop robot is designed to help people with MCI learn skills to improve memory, attention,
and executive functioning at home.
University of California San Diego, CA
E
ngineers at the University of California
San Diego in collaboration with clinicians,
people with MCI, and their care
partners have developed CARMEN, short
for
Cognitively
Assistive
Robot
for
Motivation and Neurorehabilitation - a
small, tabletop robot designed to help people
with mild cognitive impairment (MCI)
learn skills to improve memory, attention,
and executive functioning at home.
To the best of the researchers'
knowledge, CARMEN is also the only
robot that teaches compensatory cognitive
strategies to help improve memory
and executive function. " We
wanted to make sure we were provid20
ing
meaningful and practical inventions, "
said Laurel Riek, Professor of
Computer Science and Emergency
Medicine at UC San Diego and the
work's senior author.
MCI is an in-between stage between
typical aging and dementia. It affects
various areas of cognitive functioning,
including memory, attention, and executive
functioning. About 20 percent of
individuals over 65 have the condition,
with up to 15 percent transitioning to
dementia each year. Existing pharmacological
treatments have not been able to
slow or prevent this evolution, but behavioral
treatments can help.
Researchers programmed CARMEN
to deliver a series of simple cognitive
training exercises. For example, the
robot can teach participants to create
routine places to leave important objects,
such as keys; or learn note taking
strategies
to
remember
important
things. CARMEN does this through interactive
games and activities.
The research team designed CARMEN
with a clear set of criteria in mind. It is
important that people can use the robot
independently, without clinician or researcher
supervision. For this reason,
CARMEN had to be plug and play, without
many moving parts that require mainMotion
Design, August 2024

Tech Briefs Magazine - August 2024

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