Most robots are designed for a specific job, and aren’t very adaptable. But engineers at Virginia Tech have now developed a soft robot that can morph into a range of shapes, such as driving, flying or swimming robots, thanks to a rubber skin full of a metal that switches between liquid and solid forms easily.
To create a robot this versatile, the researchers started by designing a material that could change its shape on demand, hold that shape for as long as required, revert back to its original configuration, and do so many times. This material is made up of an elastomer endoskeleton, cut in a kirigami pattern of triangles. Inside this material is a network of tubes containing a metal alloy with a low melting point, along with a set of tendril-shaped heaters. The structure can be combined with actuators, motors and other components for movement and shape changing.
The idea is that the robot starts out flat, with the metal inside in its liquid form. It can be bent and stretched into the desired shape for the robot, at which point the metal hardens into a solid, keeping it in that shape. After whatever task is complete, the heaters can be switched on to warm the metal to 60 °C (140 °F), which melts it and returns the robot to its original form. From there, it’s ready to be reshaped into whatever it needs to do next. It can morph and fix into shape in less than one tenth of a second.
In tests, the team used the material to create a robot that could drive along the ground, then morph into a flying drone. Essentially, it’s a flat sheet with upwards-facing propellers in its flying configuration, and in its driving form it resembles a bent-over taco shape with wheels that touch the ground.
Another test model used the material as the basis for a submarine, which could dive to the bottom of an aquarium, scoop up marbles and bring them to the surface.
“We’re excited about the opportunities this material presents for multifunctional robots," said Edward J. Barron III, co-author of the study. "These 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.”
The research was published in the journal Science Robotics. The robot can be seen in action in a video on the Virginia Tech website.
Source: Virginia Tech