Engineers at Northwestern University have developed a tiny remote controlled crab robot. The device is just half a millimeter wide, and can perform a variety of impressive tasks, including jumping, twisting, bending, turning, and walking. The tiny devices do not require electricity and instead are powered through heating using a laser. The shape-memory alloy that forms the bulk of the robots rapidly changes shape when heated and then returns to its original shape rapidly when the heating ceases, forming the basis for the device’s movements. While in its technological infancy, the method could have eventual applicability in medicine as means to perform minimally invasive surgical tasks within the body.
“Robotics is an exciting field of research, and the development of microscale robots is a fun topic for academic exploration,” said John Rogers, who led the development of the new devices. “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.”
The tiny robots are smaller than a flea, and do not require batteries or any other on-board method of propulsion. Instead, they are composed of materials that create elastic resistance, and which can be easily manipulated using heat. The crabs are made using a shape-memory alloy. On heating with a laser the alloy returns to its “remembered” shape, and then on removal of heat a glass coating over the alloy helps it to rapidly return to its original shape.
Different movements can be created by heating different parts of the robot and rapid switching of the laser results in locomotion. Moreover, the laser operator can control the direction of motion – scanning the laser from right to left over the robots causes them to move from left to right, for example.
The tiny size of the robots is key to their rapid heating and cooling. “Because these structures are so tiny, the rate of cooling is very fast,” said Roger. “In fact, reducing the sizes of these robots allows them to run faster.”
“Our technology enables a variety of controlled motion modalities and can walk with an average speed of half its body length per second,” said Yonggang Huang, another researcher involved in the study. “This is very challenging to achieve at such small scales for terrestrial robots.”
Check out a video showing the robots moving around:
Study in Science Robotics: Submillimeter-scale multimaterial terrestrial robots