Tech Briefs Magazine - April 2024 - MD-20

Robots for Building Resilient Space Habitats
New robotic arms and grippers can enable autonomous robots repair or replace damaged components
in an extraterrestrial habitat.
Harvard SEAS, Cambridge, MA
T
he Resilient ExtraTerrestrial Habitats
institute (RETHi) is led by Purdue
University, in partnership with Harvard
John A. Paulson School of Engineering
and Applied Sciences (SEAS), the
University of Connecticut, and the
University of Texas at San Antonio. Its
goal is to " design and operate resilient
deep space habitats that can adapt, absorb
and rapidly recover from expected
and unexpected disruptions. "
Justin Werfel, Senior Research Fellow in
Robotics at SEAS, is leading the team
tasked with developing technologies to let
autonomous robots repair or replace
damaged components in a habitat.
" What happens if a meteorite breaches
the habitat between missions, and the
crew isn't there to fix it, " asked Werfel. " Or
if it happens during a crewed time, the
astronauts may have their hands full with
other emergencies. Likewise in more routine
situations; there are a lot of regular
maintenance tasks that take up valuable
astronaut time, from replacing filters to
cleaning things. You'd really like the habitat
to be able to handle as much as possible
on its own, which means robots doing
that work. "
Since the project began in 2019, Werfel
and the team, which includes Robert
Wood, the Harry Lewis and Marlyn
McGrath Professor of Engineering and
Applied Sciences at SEAS, have developed
new robotic arms and grippers, new systems
to improve human-robot collaboration
and new ways to design robot-friendly
equipment.
One of the biggest challenges in designing
robots for these so-called SmartHabs is
the multifunctionality needed for deep
space habitation. Most industrial robots,
such as those used to build cars or stock
warehouses, are highly specialized and
perform only a few specific tasks. But deep
space habitats won't have room for dozens
of specialized robots. Instead, one or a few
multifunctional robots will need to be
able to perform many different tasks, including
emergency repairs.
One project toward that end has been
to develop multi-mode grippers that can
change their shape to grasp different
types of objects in different ways.
" Human hands can adapt to many functions,
including those that need high precision,
require high forces, or those that
may benefit from compliance, " said Wood.
" This design attempts to capture analogous
adaptable behavior to increase the range
of tasks possible with a single gripper. "
In a paper published in IEEE, Werfel
and the team, which includes collaborators
from the Harvard Graduate School
of Design (HGSD) and Pusan National
University in South Korea, developed a
gripper with fingers made of so-called
scissor links, which can be reconfigured
to change the number of joints in the
finger.
This gripper has three modes. In the first,
the fingers are short and don't bend, allowing
them to strongly and securely grasp
objects. In the second mode, the fingers
gain a joint to let the gripper perform inhand
manipulation, allowing it to move
and rotate objects without letting go of
them. The last mode adds two more joints,
allowing the fingers to passively adapt to
the shape of an object and distribute contact
pressure, which is useful for grasping
irregularly shaped or delicate objects.
The first SmartHabs will likely be no
larger than a mobile home and packed to
the brim with equipment. Soft robots can
be safer to operate around humans than
traditional rigid ones, and could deform
to more easily squeeze into tight spaces,
but the softness also means they lack the
strength they might need for some of the
work they're called on to do.
To tackle that challenge, RETHi's robotics
team designed a soft robotic arm that
can stiffen up to increase its force and
payload capacity.
Each segment consists of soft joints,
which individually have only a small range
of motion, but together can bend the arm
90 degrees. A few actuators placed along
the spine and the joints can induce localized
body stiffening, which allows the arm
to pick up or move a heavy object.
Robots that can handle tasks designed
for humans is one of the long-term goals
of robotics - but it will take a long time
The gripper switches between three modes, which are suited to tasks that require maintaining a secure hold on an object or applying high pressure, precise finger
positioning or in-hand manipulation, and passive adaptation to the shape of larger, delicate, or irregularly shaped objects. (Image: Harvard SEAS)
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Motion Design, April 2024

Tech Briefs Magazine - April 2024

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