North Carolina State University (NC State) engineers have created a soft ring robot powered by infrared light that can climb an 80-degree slope and carry 12 times its weight.
Made of twisted, ribbon-like liquid crystal elastomers, the fully autonomous robot could be adapted to run on other forms of energy, including sunlight, to perform specialized tasks in hard-to-reach places.
“We’ve previously created soft robots that can move quickly through the water and across solid ground, but wanted to explore a design that can carry objects through the air across open space,” explained Jie Yin, a corresponding author of a paper detailing the work and an associate professor of mechanical and aerospace engineering at North Carolina State University.
“The simplest way to do this is to follow an established track, similar to the aerial trams you see in the mountains. And we’ve now demonstrated that this is possible.”
WATCH Video: Robot Powered by Infrared Light Climbs and Carries
To build their customized robot, the team twisted ribbon-like crystal elastomers to resemble rotini pasta before connecting the ends to create a loop. The resulting soft ring robot is then suspended from a line like an aerial tram or ski lift. Unlike a cable car or ski lift, the robot has no wheels or pulleys.
When infrared light is applied parallel to the track, the loop segment that encounters the light begins to contract. According to the team, this contraction induces a rolling motion where “the portion of the ribbon exposed to light contracts, pulling the ‘cooler’ part of the ribbon into the light.” As the infrared light heats the new portion of the loop, the previously warm portion begins to cool, resulting in repetitive, steady locomotion.
“As the ribbon turns, it’s like turning a screw, allowing the soft robot to move along the track – even when carrying cargo up steep angles,” Yin says.
A video provided by the NC State team shows how this controlled contraction and expansion propels the robot across the suspended line.
Invention Joins Growing List of Novel Robot Designs
Several novel robot designs have been developed in recent years, including robots powered by magnetic fields and specialized materials, insect robots designed to work as pollinators or swim like flatworms, a snake-like robot designed to explore Saturn’s moon Enceladus for life, and even a robot that can beat humans at table tennis. Still, until engineers successfully develop fully autonomous anthropomorphic robots that can perform nearly any task, scientists will continue to rely on robots designed for specialized functions, such as the soft ring robot powered by infrared light.
According to the engineers behind the novel invention, their ring robot can climb wires thinner than a human hair or as thick as a drinking straw. The robot can climb inclines as steep as 80 degrees and carry up to 12 times its weight. Several tests confirmed that the robot powered by infrared light could navigate over and around obstacles. According to the team, the ring climbed over knots and bulges in the line “in a controlled way.”
To test the ring robot’s versatility limits, the team put it through several additional scenarios where such a robot might encounter in a real-world application. As the video shows, the robot passed each test.
“We also showed that it can follow complex routes – it doesn’t have to be a straight line,” says Fangjie Qi, first author of the paper and a Ph.D. student at NC State. “We’ve demonstrated that it can follow curved lines, circles, three-dimensional spirals, and so on, in a controlled way.”
Evaluating Alternative Power Sources and Exploring Practical Applications
Yin said the team is currently “adapting” the robots to inputs other than infrared light. This includes exploring robots that run on different electromagnetic emissions, or even a soft ring robot that “operates in sunlight.”
While the robot powered by infrared light is not yet commercially available, the engineers behind its creation believe there are several ways a robot that can climb in this manner would be helpful in specialized situations. That adaptability, they said, could lead to several uses they haven’t even considered.
“We think the adaptability of the robot when it comes to navigating complex patterns in predictable ways holds promise for its utility in practical applications,” Qi explained.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.