Tech Briefs Magazine - January 2024 - 27

EELS creates a 3D map of its surroundings
using four pairs of stereo cameras
and LiDAR, which is similar to radar but
employs short laser pulses instead of radio
waves. With the data from those sensors,
navigation algorithms figure out the
safest path forward. The goal has been to
create library of " gaits, " or ways the robot
can move in response to terrain challenges,
from sidewinding to curling in on itself,
a move the team calls " banana. "
In its final form, the robot will contain
48 actuators - essentially little motors
- that give it the flexibility to assume
multiple configurations but add complexity
for both the hardware and software
teams. Many of them have built-in
force-torque sensing, working like a kind
of skin so EELS can feel how much force
it's exerting on terrain. That helps it to
move vertically in narrow chutes with uneven
surfaces, configuring itself to push
against opposing walls at the same time
like a rock climber.
The robot has been put to the test in
sandy, snowy, and icy environments,
from the Mars Yard at JPL to a " robot
playground " created at a ski resort in the
snowy mountains of Southern California,
even at a local indoor ice rink.
For more information, contact Melissa
Pamer at melissa.pamer@jpl.nasa.gov;
626-314-4928.
Dynamic Hydrogel Makes Soft Robot Components and
Building Blocks
The hydrogel material could make assembling complex microfluidic or soft robotic devices as
simple as putting together a LEGO set.
Brown University, Providence, RI
U
sing a new type of dual-polymer material
capable of responding dynamically
to its environment, re searchers have
developed a set of modular hydrogel components
that could be useful in a variety of
soft robotic and biomedical applications.
The components, which are patterned
by a 3D printer, are capable of bending,
twisting, or sticking together in response
to treatment with certain chemicals. The
researchers created a soft gripper capable
of actuating on demand to pick up
small objects, as well as LEGO-like hydrogel
building blocks that can be carefully
assembled then tightly sealed together
to form customized microfluidic
devices - " lab-on-a-chip " systems used
for drug screening, cell cultures, and
other applications.
The key to the new material's functionality
is its dual-polymer composition;
one polymer provides structural integrity
while the other enables the dynamic
behaviors like bending or self-adhesion.
Hydrogels solidify when the polymer
strands within them become tethered to
each other - a process called crosslinking.
There are two types of bonds that
hold crosslinked polymers together: covalent
and ionic. Covalent bonds are
quite strong but irreversible. Ionic bonds
are not quite as strong but can be reversed.
Adding ions will cause the bonds
A new kind of hydrogel material has the ability
to react dynamically to its environment - bending,
twisting, and self-adhering on demand.
The self-adhering behavior is shown on the tail
of a 3D-printed hydrogel salamander. The
self-adhering behavior was also used to make
hydrogel building blocks that fit together like
LEGO blocks. (Wong Lab/Brown University)
Tech Briefs, January 2024
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Tech Briefs Magazine - January 2024

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