Scientists have created a new type of soft robot that can carry cargo through the air by moving along thin wires or strings—similar to how cable cars or aerial trams travel.
What makes this robot special is that it’s powered by light, doesn’t need batteries, and can climb up very steep paths, even as steep as 80 degrees.
It can also carry items more than 12 times its own weight.
The invention comes from researchers at North Carolina State University. According to Jie Yin, a mechanical and aerospace engineering professor who led the project, their past robots moved well in water or on solid ground.
But this time, they wanted to build a robot that could move cargo across open spaces in the air.
Their solution was to design a robot that follows a suspended track, much like a ski lift.
The robot itself is made from a soft, ribbon-like material called a liquid crystal elastomer.
The ribbon is twisted into a spiral shape, similar to a rotini pasta noodle, and then formed into a loop that looks like a bracelet.
This loop, or “soft ring robot,” is wrapped around a wire, thread, or cable two or three times. This wrapping causes the robot to hang at an angle that matches the wire.
When infrared light shines on the robot from the side, the parts of the ribbon facing the light heat up and shrink slightly. This shrinking creates a rolling motion that pulls the cooler part of the ribbon into the light. That cooler part then heats up while the previous section cools down, causing the cycle to continue. This twist-and-roll action moves the robot forward along the wire.
Yin explains that this movement is similar to turning a screw—it keeps the robot climbing, even when it’s carrying a load or going up a steep slope.
The researchers tested the robot on different tracks and found it could move along wires as thin as a human hair or as thick as a drinking straw. It could even get past obstacles like knots in the wire. The robot was also able to travel along curved paths, including circles and spirals, not just in straight lines.
Lead author Fangjie Qi, a Ph.D. student, says the robot’s ability to follow complex routes makes it promising for real-world uses. The team is now exploring how to power the robot with other energy sources, like sunlight, to expand where and how it can be used.
This tiny robot could one day help deliver small packages or perform tasks in hard-to-reach places—all with just a bit of light.
