Noodle-like robots move through mazes without human or computer guidance

Researchers from[{” attribute=””>North Carolina State University (NCSU) and the University of Pennsylvania (Penn) have developed soft robots that are capable of navigating complex environments, such as mazes, without input from humans or computer software.

“These soft robots demonstrate a concept called ‘physical intelligence,’ meaning that structural design and smart materials are what allow the soft robot to navigate various situations, as opposed to computational intelligence,” says Jie Yin, corresponding author of a paper on the work and an associate professor of mechanical and aerospace engineering at NC State.

The soft robots are made of liquid crystal elastomers in the shape of a twisted ribbon, resembling the pasta rotini, except translucent. When you place the ribbon on a surface that is at least 55 degrees Celsius (131 degrees Fahrenheit), which is hotter than the ambient air, the portion of the ribbon touching the surface contracts, while the portion of the ribbon exposed to the air does not. This induces a rolling motion in the ribbon. And the warmer the surface, the faster it rolls.

A joint research team from NCSU and Penn recently developed an autonomous and intelligent twisted soft robot that can independently escape ordinary labyrinthine courses with obstacles without outside control and human intervention. The soft robot is made of heat-sensitive liquid crystal elastomers with a soft body resembling translucent rotins. When confronted with obstacles, he uses the embodied physical intelligence of self-rotation and self-rotation to autonomously overcome and avoid obstacles. They also show that the robot can roll on hot bulk sand dunes on its own without crashing and slipping, as well as crossing hot rocks. It can also collect heat energy from self-powered rolling mills on car roofs and barbecue grills.

“It’s been done before with sticks with smooth sides, but this shape has a drawback – when it encounters an object, it just spins in place,” says Yin. “The soft robot, which we made in the form of a twisted tape, is able to overcome these obstacles without any human or computer intervention.”

The tape robot does this in two ways. First, if one end of the tape encounters an object, the tape rotates slightly to go around the obstacle. Second, if the central part of the robot encounters an object, it “clicks”. Clicking is a quick release of stored deformation energy, which causes the tape to bounce slightly and reorient before landing. The bar may need to click more than once before finding an orientation that allows it to overcome the obstacle, but in the end it always finds a clear way forward.

“In that sense, it’s a lot like the robotic vacuum cleaners that many people use in their homes,” says Yin. “Apart from the soft robot we created, it draws energy from the environment and works without any computer programming.”

“The two actions, rotation and clicking, that allow the robot to overcome obstacles, work on a gradient,” said Yao Zhao, the first author and postdoctoral fellow in North Carolina. “The most powerful click occurs if an object touches the center of the bar. But the tape will still break if an object touches the tape away from the center, it’s just less powerful. And the farther you are from the center, the weaker the click until you reach the last fifth of the length of the bar, which doesn’t cause a click at all. ”

Researchers have conducted numerous experiments demonstrating that the soft tape-like robot is capable of moving in various maze-like environments. Researchers have also demonstrated that soft robots would work well in a desert environment, showing that they are capable of climbing and descending slopes of loose sand.

“It’s interesting and fun to watch, but more importantly, it provides new insights into how we can design soft robots that are able to collect heat from the natural environment and autonomously negotiate complex, unstructured settings such as roads and raw deserts, ”Yin says.

Reference: “Twisting for a soft intelligent autonomous robot in an unstructured environment” May 23, 2022, Notices of the National Academy of Sciences.
DOI: 10.1073 / pnas.2200265119

The document will be published in the week of May 23 at Notices of the National Academy of Sciences. The paper is co-authored by NC State Ph.D. students Yinding Chi, Yaoye Hong and Yanbin Li; and Shu Young, Professor Joseph Bordonya of Materials Science and Engineering at the University of Pennsylvania.

The work was supported by the National Science Foundation under grants CMMI-431 2010717, CMMI-2005374 and DMR-1410253.