Just a Tentacled Micro-Robot Clutching a Helpless Ant

Microscale "soft" robots are a key feature of the robotic future, but they require suitably soft ways of manipulating micro-objects. A tiny translucent tentacle might make a lot of sense.

The technology now exists, at least, courtesy of an Iowa State University-based team of engineers who've described their work in the current Scientific Reports. The point, as described in the paper, is to provide an alternative to the angular metal clutches of most of the robots we're used to, thus enabling the "non-damaging manipulation of soft, fragile micro-objects." Like ants, but a lot of other stuff that's likely biomedical in nature.

There are several problems involved in creating robots with micro-tentacles and they often reduce to fabrication technology. The appendages are pneumatically-driven—which enables the requisite softness—but the actuators needed to make that happen are generally too complex and consist of many sub-elements. The solution the ISU researchers found was a material known as polydimethylsiloxane (PDMS), a silicon-based organic polymer with the unusual property of viscoelasticity. In some conditions it behaves as a thick liquid, like honey, and in others it's more of a rubber-like solid. Jaeyoun Kim, the new paper's lead author, had previously patented a method making PDMS-based wires.

The tentacles get their ant-clutching abilities via a manipulation of the thickness of the tentacle material, such that when it's inflated it takes on a spiraling shape. To manufacture the tentacles, Kim and his group came up with a new method in which shapes are drawn lithographically, creating a template onto which PDMS can be deposited and then peeled away with the desired thickness.

"The outcome is a soft-robotic micro-tentacle that can wind around and hold fragile micro-objects with ~200 μm final spiral radius," the paper explains. "This spiraling micro-tentacle manipulator, along with the shape-engineering concept and microtube fabrication technique, are all unprecedented and poised to enrich the field of soft-robotics."

Fear not, ants of the world. These are are gentle robots—think of it as a tiny hug.

"There's microrobotics, where people want to make robots smaller and smaller," Kim notes in a statement. "And there's soft robotics, where people don't want to make robots out of iron and steel. This project is an overlap of both of those fields. I want to pioneer new work in the field with both microscale and soft robotics."