Microbotics is a burgeoning field within robotics, with future potential applications in manufacturing and medicine. In previous iterations, clusters of microbots have achieved uniform movement via magnetic coils situated around their field of operation.

Researchers at Purdue Univ., however, have developed a method to individually control microbots using a technology they likened to “mini force fields.”

The researchers published their findings in Micromachines.

“What we can do now, instead of having these coils all around on the outside, is to print planar coils directly onto the substrate,” said Purdue Univ.’s David Cappelleri, an assistant professor of mechanical engineering.

The team developed a planar magnetic coil array substrate, containing 64 magnetic coils, which each measured 4 mm. The microbots, which are magnetic disks, move across the surface via attractive and repulsive forces, and by varying the strength of the electrical current within the coils.

“Think of ants. They can independently move, yet all work together to perform tasks such as lifting and moving things,” said Cappelleri. “We want to be able to control them individually so we can have some robots here doing one thing, and some robots there doing something else at the same time.”

In a video, the researchers successfully got two disk-shaped microbots to navigate around two separate obstacles. 

Though the microbots used measure around 2 mm in diameter, the researchers are hoping to scale the size down to around 250 µm in diameter.  

Research is ongoing, but the researchers believe the microbots may one day have applications for building microelectromechanical systems (MEMS).

“So far people have been good at making MEMS devices containing different components,” said Cappelleri. “But a lot of times the components are made from different processes and then have to be assembled to make the final device. This is very challenging. We can instead assemble them with our robots. And on the biological side we might use them for cell sorting, cell manipulation, characterization, and so on. You could think about putting the microcoils at the bottom of a petri dish.”

Such microbots, outfitted with probe-like sensors could be used to differentiate between cancer and non-cancer cells during a biopsy, according to Cappelleri.