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 with NCSU and Penn recently developed an autonomous and intelligent twisted soft robot that can independently escape from simple labyrinthine lanes with obstacles without outside human control and intervention. The soft robot is made of liquid crystal elastomers that respond to heat, its soft body resembles a translucent rotini. Faced with obstacles, he uses the embodied physical intelligence of self-detachment and rotation for autonomous handling and avoidance of obstacles. They also show that the robot can roll on hot loose sand dunes without getting stuck and slipping, and cross hot rocks. It can also get thermal energy from the environment for self-riding on the car roof and barbecue grills.

“It used to be done with smooth rods, but this shape has a drawback – when it collides with an object, it just rotates in place,” says Yin. “The soft robot, which we made in the form of a twisted ribbon, is able to overcome these obstacles without human or computer intervention.”

The tape robot does this in two ways. First, when one end of the tape bumps into an object, the tape rotates slightly to get around the obstacle. Second, when the central part of the robot collides with an object, it “snaps”. Binding is the rapid release of the accumulated deformation energy, which causes the tape to bounce slightly and reorient before landing. The tape may need to be crossed several times before finding an orientation that allows it to overcome an obstacle, but ultimately it always finds a clear path forward.

“In that sense, it’s very similar to the robotic vacuum cleaners that many people use in their homes,” says Yin. “Except that the soft robot we created draws energy from its environment and works without computer programming.”

“The two actions, rotation and binding, that allow the robot to overcome obstacles, act on a gradient,” says Yao Zhao, the first author of the article and a graduate student at NC State. “The most powerful binding occurs when the object touches the center of the tape. But the tape still bursts when the object touches the tape away from the center, it’s just less powerful. And the farther from the center, the less pronounced the latch, until it reaches the last fifth length of the tape, which does not give a latch.

Researchers have conducted several experiments that have shown that a soft robot, like a ribbon, is able to move in different environments, like a maze. Researchers have also demonstrated that soft robots will work well in desert conditions, showing that they are capable of ascending and descending slopes of loose sand.

“It’s fun and fun to watch, but more importantly, it gives a new insight into how we can design soft robots that are able to collect thermal energy from the natural environment and autonomously solve complex, unstructured parameters such as roads and harsh deserts.” , Yin says.

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

The newspaper will be published in the week of May 23 Proceedings of the National Academy of Sciences. The paper is co-authored with the Ph.D. students Yinding Chi, Yaoye Hong and Yanbin Li; and Shu Yang, professor of materials science and engineering at Joseph Bordoni University of Pennsylvania.

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