- Metafluid has wide range of potential uses – including programming robots
- Scientists use tiny elastomer spheres to that change under pressure
- Matematerials have been around for years – but this new one is liquid, not solid
Scientists in the US have developed a programmable metafluid with tunable springiness, optical properties and viscosity that can be used to control robots.
Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) says that the first-of-its-kind metafluid could be used in everything from hydraulic actuators to program robots, to intelligent shock absorbers that can dissipate energy depending on the intensity of the impact, to optical devices that can transition from clear to opaque.
The metafluid uses a suspension of small, elastomer spheres — between 50 to 500 microns — that buckle under pressure, radically changing the characteristics of the fluid.
“We are just scratching the surface of what is possible with this new class of fluid,” said Adel Djellouli, a Research Associate in Materials Science and Mechanical Engineering at SEAS and first author of the paper. “With this one platform, you could do so many different things in so many different fields.”
Metamaterials — artificially engineered materials whose properties are determined by their structure rather than composition — have been used in applications for years. But most of the materials are solid.
“Unlike solid metamaterials, metafluids have the unique ability to flow and adapt to the shape of their container,” said Katia Bertoldi, William and Ami Kuan Danoff Professor of Applied Mechanics at SEAS and senior author of the paper. “Our goal was to create a metafluid that not only possesses these remarkable attributes but also provides a platform for programmable viscosity, compressibility and optical properties.”
The researchers loading the metafluid into a hydraulic robotic gripper and made it pick up a glass bottle, an egg and a blueberry. In a traditional hydraulic system powered by air or water, the robot would need some kind of sensing or external control to be able to adjust its grip and pick up all three objects without crushing them.
But with the metafluid, no sensing is needed. The liquid itself responds to different pressures, changing its compliance to adjust the force of the gripper to be able to pick up an object with no additional programming.
“We show that we can use this fluid to endow intelligence into a simple robot,” said Djellouli.
