Engineers from Northwestern University have developed a small remote-controlled robot crab. The device is only half a millimeter wide and can perform a variety of impressive tasks, including jumping, twisting, bending, turning and walking. Small devices do not require electricity and are instead powered by laser heating. The shape memory alloy that forms most robots quickly changes shape when heated and then quickly returns to its original shape when heating stops, forming the basis for the device’s movements. While in the technologically advanced stage, the method may have potential applicability in medicine as a means of performing minimally invasive surgical tasks in the body.
“Robotics is an exciting field of research, and the development of microscale robots is a fun topic for academic research,” said John Rodgers, who is leading the development of the new devices. “You can think of microrobots as tools for repairing or assembling small structures or machines in industry, or as surgical aids to clear clogged arteries, stop internal bleeding, or eliminate cancerous tumors – all with minimally invasive procedures.
Small robots are smaller than fleas and do not require batteries or other on-board propulsion methods. Instead, they are composed of materials that create elastic resistance and that can be easily manipulated with the help of heat. Crabs are made using an alloy with shape memory. When heated with a laser, the alloy returns to its “memorized” shape, and then, when the heat is removed, a glass coating on the alloy helps it to quickly return to its original shape.
Different movements can be created by heating different parts of the robot and quickly switching the laser leads to movement. In addition, the laser operator can control the direction of movement – scanning the laser from right to left over the robots causes them to move from left to right, for example.
The small size of the robots is crucial for their rapid heating and cooling. “Because these structures are so small, the cooling rate is very fast,” Roger said. “In fact, reducing the size of these robots allows them to run faster.”
“Our technology allows for different ways of controlled movement and can travel at an average speed of half the length of your body per second,” said Yongang Huang, another researcher involved in the study. “It’s a great challenge to achieve on such a small scale for ground robots.”
Watch a video that shows how robots move:
Learn in Scientific work: Submillimeter multimaterial earth robots
through: Northwestern University