This Tiny Crab Robot Is Smaller Than A Flea But Can Bend, Crawl And Even Jump

A group of Northwestern University engineers have developed the smallest-ever remote-controlled walking robot. The crab robot is just a half-millimeter wide, which is narrower than a US coin, but can bend, twist, crawl, walk, turn and even jump.

The field of robotics has seen engineers and researchers finding new and innovative ways to create fully functional micro-sized robots. The robot crab that engineers at Northwestern University devised is so small that it can stand on the edge of a penny (see top image), and is still capable of performing an array of movements via remote control. While the research is exploratory at this point, the researchers hope that their technology can bring the field of robotics closer to realizing micro-sized robots that can perform tasks in tightly confined spaces.

"Robotics is an exciting field of research, and the development of microscale robots is a fun topic for academic exploration," remarked John A. Rogers, who led the experimental work. "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."
Crab robot, which was fashioned after a peekytoe crab, is smaller than a flea, and its power resides in the elastic resilience of its body. In order to construct the robot, researchers utilized a shape-memory alloy material that transforms to its "remembered" shape when heated. In the case of the crab robot, a scanned laser beam was used to rapidly heat the robot at different targeted locations across its body. "A thin coating of glass elastically returns that corresponding part of the structure to its deformed shape upon cooling," according to a post on Northwestern Now.
Locomotion is created as the robot changes from one phase to another. The laser remotely controls the robot in order to activate it, as well as determines which direction the robot will walk. As an example, scanning from left to right causes the robot to move from right to left.

"Because these structures are so tiny, the rate of cooling is very fast," explained Rogers. "In fact, reducing the sizes of these robots allows them to run faster."

The research was published in a paper on May 25, 2022 in the journal Science Robotics. The same team that developed the crab robot published another paper in September of last year that introduced a winged microchip that was the smallest-ever human-made flying structure.

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

Top Image Credit: Northwestern University