Smarticles, short for smart active particles, are 5 centimeter-long 3D printed robots designed by Georgia Tech doctoral student Nick Gravish.  The small robots could do only one thing-flap their arms up and down.  However, when five smarticles are placed in a container, they push each other to form a supersmarticle-a robophysical system that can move by itself.  Simply put, a supersmarticle is a robot built from smaller robots.  A detailed report on the development was published in Science Robotics.

Gravish worked with Georgia Tech physicist Dan Goldman, who clarified the simplicity of their work.  "These are very rudimentary robots whose behavior is dominated by mechanics and the laws of physics," he said. "We are not looking to put sophisticated control, sensing and computation on them all. As robots become smaller and smaller, we'll have to use mechanics and physics principles to control them because they won't have the level of computation and sensing we would need for conventional control."

When designed with a light or sound sensor, the robot complex would be able to move depending on its defined response to external stimuli.  This idea came from an observation that when one of the smarticles stopped moving, its robot friends would move towards it.  This happens when, say the battery of one of the robots die.  Adding a light sensor to each smarticle would keep it from moving when activated by a light stimulus.  "If you angle the flashlight just right, you can highlight the robot you want to be inactive, and that causes the ring to lurch toward or away from it, even though no robots are programmed to move toward the light," Goldman explained. "That allowed steering of the ensemble in a very rudimentary, stochastic way."

For future studies, the researchers are looking into altering the geometry of each smarticle and how this would affect the formation of a unified robotic system.  Having been working with the Army Research Laboratory, the researchers think that this kind of system would be particularly useful in the field to enhance surveying and awareness in areas that are difficult to maneuver, like forests or caves.  Army research office complex dynamics and systems program manager Sam Stanton agreed and even gave an example.  "For example, as envisioned by the Army Functional Concept for Maneuver," said Stanton, "a robotic swarm may someday be capable of moving to a river and then autonomously forming a structure to span the gap."