A crab robot so small it fits in the hole of a needle

This is the smallest robot in the world created to date, by Northwestern University, United States

Crab robot. (photo: Northwestern University)

It can hardly be seen with the naked eye, because it is fifty times smaller than half a millimeter, but the robot built by researchers at Northwestern University (Illinois, United States), is shaped like a crab and is able to walk on the edge of a coin. It is the smallest walking robot in history and its creators have just told the journal Science Robotics how they managed to make it.

Robots of this size have a host of potential uses: from helping with surgical procedures to repairing machinery in spaces where a wrench won’t fit, for example. The smaller they are, the more scenarios they can be used in. And this tiny robot, although it will not yet be manufactured industrially, may have many uses for the future.

With the appearance of a crab, also performs the same movements as this crustacean. And while robots normally take forms inspired by nature for practical reasons, in this case it was just a “creative whim”, according to the researchers, as the technique they have developed can be used to make small robots in almost any shape required.

This is how the technology of the world’s smallest robot works

“Our technologyit allows for a variety of controlled movement modalities and can walk at an average speed of half its body length per second,” says Yonggang Huang, a mechanical engineer at Northwestern University in Illinois. “This is very difficult for terrestrial robots to achieve at such small scales,” he added.

The technology on which the robot is based was originally developed eight years ago: the robot parts are attached to a stretched rubber substrate, and as the material relaxes, the device takes its shape.

By carefully calibrating the base parts, the shape of the robot can be precisely controlled. A similar approach is used with moving parts, which are made of an alloy material that changes shape depending on whether or not it is heated.

crab robot. (photo: Northwestern University)

Lasers, which act as a remote control, are used to heat specific parts of the robot; as those parts morph into a different shape, they propel the crab forward. No power supply or motor is needed, and a thin layer of glass ensures that the components return to their shape original as they cool.

“Because these structures are so small, the cooling rate is very fast,” says John Rogers, a materials scientist at Northwestern University, adding, “in fact, reducing the size of these robots it allows you to run faster.”

By aiming the lasers at different sections of the ‘robo-crab’, the researchers can establish the direction of locomotion. By adjusting the frequency of the laser scanning, the speed of movement of the robot can also be modified.

Crab robot. (photo: Northwestern University)

The researchers say there is a lot of potential in their new process: they can make robots turn and jump using the same techniques, for example. As long as the robot is within the line of sight of the laser, it can be manipulated remotely.

“Robotics is an exciting field of research, and the development of microscale robots it is a fun topic for academic exploration”, Rogers mentions and concludes “you can imagine micro-robots as agents to repair or assemble small structures or machines in industry or as surgical assistants to clear clogged arteries , stop internal bleeding or eliminate cancerous tumors, all in minimally invasive procedures.”