Bioinspired soft actuator crawls without rigid parts
Who needs legs? With their sleek bodies, snakes can slither up to 14 miles-per-hour, squeeze into tight space, scale trees and swim. How do they do it? It's all in the scales. As a snake moves, its scales grip the ground and propel the body forward - similar to how crampons help hikers establish footholds in slippery ice. This so-called friction-assisted locomotion is possible because of the shape and positioning of snake scales.
Video: Harvard researchers have developed a soft robot inspired by snakes. The robot is made using kirigami -- an ancient Japanese paper craft that relies on cuts, rather than origami folds, to change the properties of a material. As the robot stretches, the flat kirigami surface is transformed into a 3D-textured surface, which grips the ground just like snakeskin.
Credit: Harvard SEAS
Now, a team of researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has developed a soft robot that uses those same principles of locomotion to crawl without any rigid components.
The soft robotic scales are made using kirigami - an ancient Japanese paper craft that relies on cuts, rather than origami folds, to change the properties of a material. As the robot stretches, the flat kirigami surface is transformed into a 3D-textured surface, which grips the ground just like snakeskin.
The research is published in Science Robotics.
"There has been a lot of research in recent years into how to fabricate these kinds of morphable, stretchable structures," said Ahmad Rafsanjani, a postdoctoral fellow at SEAS and first author of the paper. "We have shown that kirigami principles can be integrated into soft robots to achieve locomotion in a way that is simpler, faster and cheaper than most previous techniques."
The researchers started with a simple, flat plastic sheet. Using a laser cutter, they embedded an array of centimeter-scale cuts, experimenting with different shapes and sizes. Once cut, the researchers wrapped the sheet around a tube-like elastomer actuator, which expands and contracts with air like a balloon.
When the actuator expands, the kirigami cuts pop-out, forming a rough surface that grips the ground. When the actuator deflates, the cuts fold flat, propelling the crawler forward.
The researchers built a fully untethered robot, with its integrated onboard control, sensing, actuation and power supply packed into a tiny tail. They tested it crawling throughout Harvard's campus.
The team experimented with various-shaped cuts, including triangular, circular and trapezoidal. They found that trapezoidal cuts - which most closely resemble the shape of snake scales -gave the robot a longer stride.
"We show that the locomotive properties of these kirigami-skins can be harnessed by properly balancing the cut geometry and the actuation protocol," said Rafsanjani. "Moving forward, these components can be further optimized to improve the response of the system."
"We believe that our kirigami-based strategy opens avenues for the design of a new class of soft crawlers," said Katia Bertoldi, the William and Ami Kuan Danoff Professor of Applied Mechanics and senior author of the paper. "These all-terrain soft robots could one day travel across difficult environments for exploration, inspection, monitoring and search and rescue missions or perform complex, laparoscopic medical procedures."
Bertoldi is also an Associate Faculty of the Wyss Institute for Biologically Inspired Engineering at Harvard University.
This research was co-authored by Yuerou Zhang, Bangyuan Liu and Shmuel M. Rubinstein, Associate Professor of Applied Physics at SEAS. It was supported by the National Science Foundation.
Leah Burrows | EurekAlert!
Marine Skin dives deeper for better monitoring
23.04.2019 | King Abdullah University of Science & Technology (KAUST)
CubeSats prove their worth for scientific missions
17.04.2019 | American Physical Society
Researchers led by Francesca Ferlaino from the University of Innsbruck and the Austrian Academy of Sciences report in Physical Review X on the observation of supersolid behavior in dipolar quantum gases of erbium and dysprosium. In the dysprosium gas these properties are unprecedentedly long-lived. This sets the stage for future investigations into the nature of this exotic phase of matter.
Supersolidity is a paradoxical state where the matter is both crystallized and superfluid. Predicted 50 years ago, such a counter-intuitive phase, featuring...
A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter
A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.
Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...
The technology could revolutionize how information travels through data centers and artificial intelligence networks
Engineers at the University of California, Berkeley have built a new photonic switch that can control the direction of light passing through optical fibers...
Physicists observe how electron-hole pairs drift apart at ultrafast speed, but still remain strongly bound.
Modern electronics relies on ultrafast charge motion on ever shorter length scales. Physicists from Regensburg and Gothenburg have now succeeded in resolving a...
17.04.2019 | Event News
15.04.2019 | Event News
09.04.2019 | Event News
23.04.2019 | Information Technology
23.04.2019 | Earth Sciences
23.04.2019 | Life Sciences