Researchers Create Self-Reconfigurable Swarms of Multi-Legged Robots
Ozkan-Aydin & Goldman showed through a series of experiments that a swarm of chainable legged robots is capable of locomoting on challenging environments and accomplishing complex tasks that are not achievable by individual robots. Image credit: University of Notre Dame.
A team of U.S. researchers has developed a reconfigurable swarm of identical low-cost four-legged robots — with directionally flexible legs and tail — that can be linked on demand and autonomously.
“Legged robots can navigate
challenging environments such as rough terrain and tight spaces, and the use of
limbs offers effective body support, enables rapid maneuverability and
facilitates obstacle crossing,” said Dr. Yasemin Ozkan-Aydin, a robotics
engineer in the Department of Electrical Engineering at the University of Notre
Dame and the School of Physics at the Georgia Institute of Technology.
“However, legged robots face unique
mobility challenges in terrestrial environments, which results in reduced
locomotor performance.”
For the study, Dr. Ozkan-Aydin and her colleague, Professor Daniel Goldman from the Georgia Institute of Technology, hypothesized that a physical connection between individual robots could enhance the mobility of a terrestrial legged collective system.
Individual robots performed simple
or small tasks such as moving over a smooth surface or carrying a light object,
but if the task was beyond the capability of the single unit, the robots
physically connected to each other to form a larger multi-legged system and
collectively overcome issues.
“When ants collect or transport
objects, if one comes upon an obstacle, the group works collectively to overcome
that obstacle,” Dr. Ozkan-Aydin said.
“If there’s a gap in the path, for
example, they will form a bridge so the other ants can travel across — and that
is the inspiration for this study.”
“Through robotics we’re able to gain
a better understanding of the dynamics and collective behaviors of these
biological systems and explore how we might be able to use this kind of
technology in the future.”
Using a 3D printer, the scientists
built four-legged robots measuring 15 to 20 cm (6-8 inches) in length.
Each was equipped with a lithium
polymer battery, microcontroller and three sensor: a light sensor at the front
and two magnetic touch sensors at the front and back, allowing the robots to
connect to one another.
Four flexible legs reduced the need
for additional sensors and parts and gave the robots a level of mechanical
intelligence, which helped when interacting with rough or uneven terrain.
“You don’t need additional sensors
to detect obstacles because the flexibility in the legs helps the robot to move
right past them,” Dr. Ozkan-Aydin said.
“They can test for gaps in a path,
building a bridge with their bodies; move objects individually; or connect to
move objects collectively in different types of environments, not dissimilar to
ants.”
The researchers tested their robots
over grass, mulch, leaves and acorns.
The robots were also tested over
shag carpeting, and rectangular wooden blocks were glued to particle board to
serve as rough terrain.
When an individual unit became
stuck, a signal was sent to additional robots, which linked together to provide
support to successfully traverse obstacles while working collectively.
“There are still improvements to be
made on our design,” Dr. Ozkan-Aydin said.
“But we expect the findings will
inform the design of low-cost legged swarms that can adapt to unforeseen
situations and perform real-world cooperative tasks such as search-and-rescue
operations, collective object transport, space exploration and environmental
monitoring.”
The team’s work was
published in the journal Science Robotics.
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Yasemin Ozkan-Aydin &
Daniel I. Goldman. 2021. Self-reconfigurable multilegged robot swarms
collectively accomplish challenging terradynamic tasks. Science
Robotics 6 (56); doi: 10.1126/scirobotics.abf1628