Tech Briefs Magazine - August 2023 - MD-24

Grounded to water
Buoyancy unit
Stiffening layer
0 V
Waterproof layer
(elastic layer)
Flexible electrode
Polymer film
Liquid dielectric
Polymer film
Stabilization unit
Magnified
φ
Water
Padding
Ions in water
The robot consists of several layers: some stiffen the robot, others serve to keep it afloat or insulate it. (Image: MPI-IS)
liquid dielectric-filled plastic pouches that
are partially covered by electrodes.
Applying a high voltage across an electrode
charges it positively, while surrounding
water is charged negatively.
This generates a force between positively-charged
electrode and negatively-charged
water that pushes the oil inside
the pouches back and forth, causing
the pouches to contract and relax -
resembling a real muscle. HASELs can
sustain the high electrical stresses generated
by the charged electrodes and are
protected against water by an insulating
layer. This is important, as HASEL muscles
were never before used to build an
underwater robot.
Jellyfish-Bots are capable of moving
and trapping objects without physical
contact, operating either alone or with
several in combination. Each robot
works faster than other comparable inventions,
reaching a speed of up to 6.1
cm/s. Moreover, it only requires a low
input power of around 100 mW and it
is safe for humans and fish should the
polymer material insulating the robot
one day be torn apart.
Meanwhile, the noise from the robot
cannot be distinguished from background
levels. In this way Jellyfish-Bot
interacts gently with its environment
without disturbing it - much like its
natural counterpart.
For more information, contact Linda
Behringer at linda.behringer@is.mpg.
de; +49 151-2300-1111.
Four-Legged Robotic System Walks a Balance Beam
Spacecraft-inspired system enhances quadruped agility and balance.
Carnegie Mellon University, Pittsburgh, PA
R
esearchers in Carnegie Mellon
University's Robotics Institute (RI)
have designed a system that makes an offthe-shelf
quadruped robot nimble enough
to walk a narrow balance beam - a feat
that is likely the first of its kind.
" This experiment was huge, " said
Zachary Manchester, an Assistant Professor
in the RI and head of the Robotic
Exploration Lab. " I don't think anyone
has ever successfully done balance beam
walking with a robot before. "
By leveraging hardware often used to
control satellites in space, Manchester
and his team offset existing constraints
in the quadruped's design to improve its
balancing capabilities.
The standard elements of most modern
quadruped robots include a torso and
four legs that each end in a rounded foot,
allowing the robot to traverse basic, flat
surfaces and even climb stairs. Their design
resembles a four-legged animal, but
unlike cheetahs who can use their tails to
control sharp turns or falling cats that adjust
their orientation in mid-air with the
help of their flexible spines, quadruped
robots do not have such instinctive agility.
24
A team of Robotics Institute researchers has designed a system that makes an off-the-shelf quadruped robot
nimble enough to walk a narrow balance beam - a feat that is likely the first of its kind. (Image: CMU)
Motion Design, August 2023

Tech Briefs Magazine - August 2023

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