This Tiny Crab Is The World's Smallest Remote-Control Walking Robot

EVANSTON, IL — The smallest crab in the world is actually a robot.

Northwestern University engineers recently developed the smallest-ever remote-controlled walking robot — and the half-millimeter-wide device comes in the form of a crab, littler than even the dime-sized pea crab.

The research behind the robot was published Wednesday in the journal “Science Robotics.” The tiny crab can bend, twist, crawl, walk, turn and jump. Although the research is exploratory, the team behind it believes their technology could be a step toward realizing micro-sized robots that can perform practical tasks in confined spaces.

“You might imagine micro-robots as agents to repair or assemble small structures or machines in industry or as surgical assistants to clear clogged arteries, to stop internal bleeding or to eliminate cancerous tumors — all in minimally invasive procedures,” said John Rogers, the professor who led the work, in a news release from Northwestern.

The team also developed millimeter-sized robots resembling inchworms, crickets and beetles. Last September, they introduced a winged microchip that was the smallest-ever human-made flying structure.

Tinier than a flea, the crab robot is constructed using shape-memory alloy material that transforms when heated. The researchers use a laser beam to rapidly heat the robot in targeted spots, and as the crab changes shape, it moves. The team also used a controlled buckling process inspired by children’s pop-up books to manufacture the robot.

But why is the device shaped like a crab? Credit for that idea goes to the students of Rogers and his collaborator, professor Yonggang Huang.

“With these assembly techniques and materials concepts, we can build walking robots with almost any sizes or 3D shapes,” Rogers said in the news release. “But the students felt inspired and amused by the sideways crawling motions of tiny crabs. It was a creative whim.”