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In nature, organisms can often change shape to perform different tasks, such as how plants move to capture sunlight throughout the day. The octopus dramatically reshapes to move, eat, and interact with its environment. Drawing its inspiration from these phenomena, a new soft robot can morph from a ground to an air vehicle. It does that by melting the metal within its skeleton, all without gears or motors.
In a new study, researchers from Virginia Tech looked for a material that could “change shape, hold that shape, and then return to the original configuration, and to do this over many cycles,” study senior author Michael Bartlett said. “One of the challenges was to create a material that was soft enough to dramatically change shape, yet rigid enough to create adaptable machines that can perform different functions.”
The applications for this technology are only starting to unfold. The functional drone autonomously morphs from a ground to air vehicle. The team also created a small, deployable submarine, using the morphing and returning of the material to retrieve objects from an aquarium. The material presents opportunities for multifunctional robots. “The composites are strong enough to withstand the forces from motors or propulsion systems, yet can readily shape morph, which allows machines to adapt to their environment,” according to the researchers.
To create a structure that could be either flexible or rigid, the scientists turned to kirigami, the Japanese art of making shapes out of paper by cutting. To help this skeleton return to its original shape, soft, tendril-like heaters could melt the metal at 140 degrees Fahrenheit (60 degrees Celsius). After the metal cooled, it could again contribute to holding a new shape.
In experiments, the researchers found this design could morph flat sheets into complex, load-bearing shapes in less than a tenth of a second. Also, if the material broke, it could heal multiple times by melting and reforming the metal skeleton.
Using this design, the researchers built a soft robot that could transform from a folded ground vehicle to a flat air vehicle, with rotors on the corners of the machine serving as wheels on the ground and propellers in the air.
The research findings were published in the journal Science Robotics.
Looking forward, the researchers envision the morphing composites playing a role in the emerging field of soft robotics to create machines that can perform diverse functions, self-heal after being damaged to increase resilience, and spur different ideas in human-machine interfaces and wearable devices, according to vtx.vt.edu.