A light-controlled tubular soft robot can pump liquids, unscrew bolts, and travel through pipes. The robot can also be designed to bend in the direction of a light source, such as a plant leaning toward the sun.
In some materials, the molecules can gain energy from light, causing the material to expand or contract. Jiuan Lv at Westlake University in China used this effect to prototype a soft robot made of a tube 15 to 40 millimeters long.
He and his colleagues wound filaments of a light-sensitive elastic material into an arrangement inspired by an elephant’s trunk, which has layers of muscle fibers pushed together in such a way that they can assume many different shapes depending on which ones are stretched.
Instead of the robot’s fibers responding to electrical signals from the brain, like in an elephant, they responded to light. When illuminated with light of different frequencies and intensities, the robot takes different forms.
In one experiment, the researchers filled the robot with a liquid and connected it to a tube that led to a raised container. Using light to make the robot contract, it pumped the liquid up and into the container. In another, they slid the robot through a curved tube that had a bolt at the bottom. When her supple body connected to the bolt, investigators shined light on it to make it rotate and unscrew the bolt.
But Lv is more excited about an experiment in which they figured out how to coil light-sensitive fibers into the shape of an artificial plant that combined bending and twisting motions to move toward light. When the light was very bright, the robot could also move away from it.
shengqiangcai at the University of California, San Diego, says this adaptive behavior is impressive and may be useful for developing devices that can continue to adjust as they absorb and collect energy from the sun.
