Building materials of the future will know how to crawl and fight back

Engineers have created a tiny robot using metasheet technology, which could give birth to the next generation of ‘alive’ and responsive materials.

In Cornell University's physics lab, scientists have created a robot as small as 1 millimeter that can morph into preprogrammed 3D shapes and crawl. The lab has previously made microrobots that can move their limbs, pump water with artificial cilia, and walk on their own. This time, it was the shapeshifter's turn.

According to one of the researchers, Qingkun Liu, the origins of the shapeshifting robot were inspired by "living organisms that can change their shape."

"When people make a robot, once it's fabricated, it might be able to move some limbs but its overall shape is usually static. So we've made a metasheet robot. The 'meta' stands for metamaterial, meaning that they're composed of a lot of building blocks that work together to give the material its mechanical behaviors," Liu explained.

While inspired by nature, the team's next research phase will move beyond it. By combining flexible mechanical structures with electronic controllers, they aim to create ultra-responsive "elastronic" materials with properties that cannot be found in nature.

The robot’s design

The creature was printed as a 2D hexagonal tiling called 'metasheet.' The tiling is composed of approximately 100 silicon dioxide panels connected through more than 200 actuating hinges, each about 10 nanometers thin. The robot’s versatility is thanks to a kirigami-inspired design, where cuts in the material let it fold, expand, and move. Kirigami is a variation of origami that involves cutting the paper, as opposed to origami, which only involves folding.

When activated by external wires, the hinges create folds that make the robot’s panels open, rotate, and change shape. This lets the robot expand or contract by up to 40%, allowing it to wrap around objects and then return to a flat shape.

The future of building stuff

Potential applications of the technology include reconfigurable micromachines, miniaturized biomedical devices, and materials that can respond to impacts almost at the speed of light, rather than the speed of sound.

Each building block's electronics can harvest energy from light, allowing a user to design materials that respond in programmed ways to different stimuli. When stimulated, these materials could, instead of merely deforming, "run" away or push back with greater force than the initial impact.

"We think that these active metamaterials – these elastronic materials – could form the basis for a new type of intelligent matter governed by physical principles that transcend what is possible in the natural world," said Itai Cohen, professor of physics.

The research was published in Nature Materials.

Further advancements in robotics

Robotics scientists have been eager to create shape-shifting robots. Earlier this year, researchers from North Carolina State University drew inspiration from origami to create shape-shifting bots that can change shape 1000 times. Scientists stressed that shape-morphing abilities are essential for multifunctionality in biological and artificial systems.

Also, the quest for nanorobotics is making scientists search for smaller and smaller solutions. For example, a team of researchers at the University of Edinburgh released billions of nanobots into arteries during lab tests to see if they can be safely used to treat brain aneurysms by controlling internal bleeding in a highly targeted and minimally invasive way.

In mid-August, engineers at the Massachusetts Institute of Technology (MIT) developed sand-sized batteries capable of powering tiny robots that can deliver drugs inside the human body or inspect pipes, potentially bringing further breakthroughs in the healthcare and energy sectors.