We’ve covered some cool crawling snake robots before here at Digital Trends, but most of these differ from real-life serpents in one crucial way: They don’t have scaly skin. While that might sound like a matter of aesthetics more than practicality, in fact, a snake’s skin plays a crucial role in helping them crawl about; enabling them to grip onto surfaces to gain the necessary friction to move forward.
That is something that researchers at Harvard University are aiming to set straight and they are turning to the ancient Japanese paper cutting art of kirigami to help them. The resulting laser-cut material is a low-cost textured skin, designed to help robots better maneuver on rough surfaces.
“Although bio-inspired soft machines made of highly deformable materials are enabling a variety of innovative applications, their locomotion typically requires several actuators that are independently activated,” Katia Bertoldi, professor of Applied Mechanics at Harvard, told Digital Trends. “In this work, we harness kirigami principles to significantly enhance their ability to crawl. We [designed] highly stretchable kirigami surfaces comprising periodic arrays of cuts and exploit mechanical instabilities to induce a transformation from flat sheets to 3D-textured surfaces akin to the scaled snakeskin.”
By wrapping their artificial scaly skin around simple tube-like robots containing air-powered actuators, the researchers found that there was a dramatic change in their frictional properties, giving the robot-enhanced crawling capabilities. Inflating the actuator caused the snake robot to move forward by popping up the scales so that they gripped the ground. Deflating the actuator flattened the scales, which anchored the robot so that it didn’t slide backward. By carrying out a continuous inflation and deflation, the snake robot was able to slither forward like … well, a snake.
Interestingly, the team discovered that switching between different shapes of the scales — such as triangular, circular, trapezoidal or linear — changed the speed and the efficiency of the crawling action.
“We believe that our kirigami-based strategy opens avenues for the design of a new class of soft crawlers that can travel across complex environments for search and rescue, exploration and inspection operations, environmental monitoring and medical procedures,” Bertoldi continued.
She said that there are no current plans for commercialization of the technology, although the team does plan to continue developing it. Future steps will involve applying the principles to different types of soft actuators, such as those based on dielectric elastomers and shape memory alloys, as well as using kirigami skins to explore and enhance other types of motions.
A paper describing the work was recently published in the journal Science Robotics.