'Mini force fields' used to control tiny robots

Researchers hope to shrink the microrobots down to 250 microns, as small as a dust mite.

By Brooks Hays

WEST LAFAYETTE, Ind., Jan. 14 (UPI) -- Researchers at Purdue University are hoping to deploy teams of tiny robots in fields ranging from manufacturing to medicine. To control them, scientists have developed a technology likened to "mini force fields."

Researchers want the robots to work cooperatively, but be controlled individually. To do so, they built miniature remote controls made of planar coils. The coils can emit individualized magnetic fields.


"The robots are too small to put batteries on them, so they can't have onboard power," David Cappelleri, an assistant professor of mechanical engineering at Purdue University, said in a press release. "You need to use an external way to power them. We use magnetic fields to generate forces on the robots. It's like using mini force fields."

Previously, researchers have positioned planar coils on the outskirts of the "workspace" where the robots have been deployed. But this technique exerts only a general force field. Cappelleri and his colleagues came up with a new technique for yielding more intimate control.

"The approach we came up with works at the microscale, and it will be the first one that can give truly independent motion of multiple microrobots in the same workspace because we are able to produce localized fields as opposed to a global field," Cappelleri said. "What we can do now, instead of having these coils all around on the outside, is to print planar coils directly onto the substrate."


Researchers can vary the forces exerted on individual robots my manipulating the strength of the electric current running through the tiny coils.

Early tests used robots with a diameter of two millimeters, twice the size of a pinhead, but researchers hope to shrink the microrobots down to 250 microns, as small as a dust mite.

Once perfected, scientists say they could perform additive manufacturing -- assembling delicate electronic components. Or they could be put to work in a petri dish sorting cells. They could even be outfitted with probes and sent in search of cancer cells.

"Cancer cells have different stiffness characteristics than non-cancer cells, and in some of our previous work we put force sensors on the end of these robots to figure out which ones are stiffer than others," Cappelleri said.

The research is ongoing, but their progress was detailed in a recent scientific paper published in the journal Micromachines.

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