Researchers from the universities of Michigan and Pennsylvania have debuted what they said is the world’s smallest programmable, autonomous robots.
The swimming microbots are designed for deployment in the medical industry, capable of monitoring individual cell health and helping construct “microscale devices.”
Measuring around 200 by 300 by 50 millimeters (smaller than a grain of salt), the tiny robots are designed to independently sense and navigate their surroundings, detecting temperatures to within a third of a degree Celsius.
Their temperature sensitivity also means they can move toward areas of increasing temperatures, and use heat variations to monitor cellular-level health. Changes in temperature are communicated by the robots through a “waggle dance,” similar to that used by honeybees to communicate.
According to the team, the microbots can operate for months and cost just a penny each.
“We’ve made autonomous robots 10,000 times smaller,” said Marc Miskin, assistant professor in electrical and systems engineering at Penn, in a press release. “That opens up an entirely new scale for programmable robots.”
Operating in water typically brings problems with drag and viscosity. Rather than attempting to push against the resistance directly, the team developed a propulsion system that moves the surrounding water instead.
The robots generate an electrical field that nudges ions in the liquid, which then push nearby water molecules, creating enough force to move the robot.
By adjusting this electrical field, the robots can travel in complex patterns or coordinate in groups, similar to a school of fish, and reach speeds of up to one body length per second.
The microbots are both powered and programmed using light pulses, and each carries a unique identifier that enables individualized programming. This makes it possible for groups of robots to divide tasks, with each unit performing a different role.
The researchers say the work represents the first time a sub-millimeter robot has been equipped with a complete computing system, including a processor, memory and sensors.
Looking ahead, the team said future iterations of the microrobots could store more complex programs, move faster, integrate additional sensors or operate in more demanding environments.
“This is really just the first chapter,” Miskin said. “We’ve shown that you can put a brain, a sensor and a motor into something almost too small to see, and have it survive and work for months. Once you have that foundation, you can layer on all kinds of intelligence and functionality. It opens the door to a whole new future for robotics at the microscale.”