Each one is about half a millimeter wide, which is smaller than the thickness of a penny in the United States.
Co-author John A. Rogers, the Louis Simpson and Kimberly Querrey Professor of Materials Science and Engineering at Northwestern University, said it took a year and a half to create the tiny metallic creatures.
He said his team is made up of students from various academic levels who have combined critical and creative thinking skills to design robots that look like crab as well as other animals such as tiny worms and crickets.
Rogers said that some students found the crab’s lateral movement amusing, which was the inspiration behind the crab’s robot. He added that the little robot can also twist, turn and jump.
The robots, made of a malleable memory alloy, start out as flat objects, similar to a piece of paper. He said the legs and arms are bent so the robot can stand. Rogers said the crab stays on its legs until heat is used to move it.
He explained that a metal object made of a shape memory alloy can deform but return to its original shape once heat is applied to it.
The ‘original’ form of cancer is when it is flat while the ‘distorted’ form is when the arms and legs are bent.
Rogers said the crab stays on its legs until laser heat is used to move the crab.
His team will heat up some of the joints to return them partially to their original, flat state. When heat was applied repeatedly in a certain sequence, the crabs were able to move, similar to the way humans bend and straighten their legs to walk.
The laser was used to apply heat to different parts of the crab’s robot to create movement, according to Rogers.
“Lasers are a convenient way to do this because we can focus light on a very small spot, and we can scan that spot to illuminate different parts of the robot’s body in a time sequence,” he said.
The robots are still in the development stage and were created primarily for academic purposes, Rogers said, but the technology used to make tiny crabs has potential.
He said the tiny crab robots could be used to perform minimally invasive surgeries or help assemble and repair small machines.
Meanwhile, Rogers has challenged his team to expand the capabilities of the robot.
“As an ambitious goal, I asked the students to see if they could come up with a way to get these robots to fly — perhaps impossible, but fun to think about,” he said.
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