Good Vibrations Get These Micro-Bristlebots Swarming and Separating On-Demand

Researchers from Georgia Tech, theUniversity of Waterloo, University of California Irvine, and Amazon Robotics have come up with a new way to control swarms of tiny robots — using vibrations.

"By collaborating with roboticists we were able to 'close the gap' between single robot design and swarm control," explains assistant professor Azadeh Ansari of the team's work. "So I guess the different elements were there, and we just made the connection."

That connection: the ability to control large-scale swarms of small-scale microrobots, even when they lack on-board sensing capabilities, through vibration alone — letting the bristle-bots aggregate and disperse under direct control, working in collaboration.

"Microbots are too small to interpret and make decisions," Zhijian Hao, PhD student first author of the work, explains, "but by using the collision between them and how they respond to frequency and the amplitude of global vibration actuation, we could influence how individual robots move and the collective behaviors of hundreds and thousands of these tiny robots."

Based on motility-induced phase separation (MIPS), a concept borrowed from the field of thermodynamics, adjusting the vibration allows the robots to come together in a swarm and disperse again — as proven using an experimental system that put 300 tiny 3D-printed micro-bristlebot robots under the camera of a computer vision system.

"This project is the first complete pipeline using this MIPS that can be generalized to different microbot swarms," claims Hao. "We hope people will find that using physical interactions is another new way to control the microbots, which initially was very difficult to do."

The team's work has been published in the journal IEEE Transactions on Robotics under closed-access terms.