Soft Robot Breaks New Ground: Climbs Steep Aerial Tracks While Carrying Heavy Cargo

High-Wire Act: Soft Robot Can Carry Cargo Up and Down Steep Aerial Wires Researchers at North Carolina State University have developed a light-powered soft robot capable of transporting loads through the air along predetermined tracks, much like cable cars or aerial trams. This robot operates autonomously and can ascend slopes at angles of up to 80 degrees, all while carrying loads as heavy as 12 times its own weight. "Previously, we've created soft robots that can swiftly maneuver through water and traverse solid ground," explains Jie Yin, the corresponding author of the study and an associate professor of mechanical and aerospace engineering at NC State. "However, we were interested in designing one that could transport objects through the air over open spaces. The simplest approach was to emulate the aerial tram systems seen in mountainous regions, and we have successfully shown that this is feasible." The soft robot is constructed from ribbon-like liquid crystal elastomers, which are twisted to resemble a rotini noodle and then joined at the ends to form a loop, akin to a bracelet. This loop, called a "soft ring robot," is suspended on a track, which can be a thread, wire, cable, or any similar material. To facilitate movement, the ring is looped around the track two or three times, ensuring it hangs at an angle parallel to the track. Infrared light, positioned perpendicularly to the track, triggers the robot's motion. The side of the ribbon that absorbs the most light contracts, initiating a rolling action. As this contracted section rolls, it pulls the cooler part of the ribbon into the light, causing it to heat up and contract. Simultaneously, the originally heated section cools and relaxes, completing the cycle. This continuous rolling and twisting movement enables the soft robot to pull itself along the track, even when ascending steep inclines. "As the ribbon turns, it acts like a screw, propelling the soft robot forward and up the track, regardless of the load it carries," Yin elaborates. The researchers conducted extensive tests to demonstrate the versatility of the soft ring robot. It successfully navigated tracks ranging from the thickness of a human hair to that of a drinking straw. Additionally, the robot was adept at overcoming obstacles on the track, including knots and bulges. Notably, it could handle slopes of up to 80 degrees and carry loads significantly heavier than itself. "Fangjie Qi, the lead author of the paper and a Ph.D. student at NC State, adds, "We also showed that the soft ring robot can follow complex routes, not just straight lines. It can traverse curved lines, circles, and three-dimensional spirals with precision, showcasing its adaptability to various patterns." The potential applications for this technology are promising. The adaptability and precision of the soft ring robot make it suitable for a range of tasks, from transportation in remote or challenging environments to precision movements in manufacturing settings. Yin concludes, "We are now exploring specific applications for this technology and considering ways to enhance the soft robots to respond to different types of external stimuli. For instance, we aim to develop a version that operates using sunlight or other energy sources, expanding its utility and versatility." This innovation marks a significant step forward in the realm of soft robotics, offering new possibilities for aerial transportation and manipulation in various fields.