New soft robots poised to be more agile, controlled


Newswise – ITHACA, NY – One of the virtues of untethered soft robots is their ability to mechanically adapt to their environment and tasks. Now they are ready to become even more agile and composed.

A team of researchers led by Kirstin Petersen, an assistant professor of electrical and computer engineering at Cornell University, designed a new — and surprisingly simple — system of fluid-powered actuators that allow soft robots to perform more complex movements. The researchers achieved this by taking advantage of the very thing – viscosity – that had previously hindered the movement of fluid-powered soft robots.

The team’s paper, “Harnessing Nonuniform Pressure Distributions in Soft Robotic Actuators,” published in Advanced Intelligent Systems.

Petersen’s Collective Embodied Intelligence Lab has been exploring ways to take a robot’s cognitive abilities and behavior from the “brain” to the body, via the robot’s mechanical reflexes. Reducing the need for explicit calculations can make the robot simpler, more robust and less expensive to produce.

“Soft robots have a very simple structure, but can work much more flexibly than their rigid cousins. They’re kind of like the ultimate embodied intelligent robot,” Petersen said. “Most soft robots today are fluid-powered. In the past, most people have looked at how we could get extra bang for our buck by embedding functionality into the robotic material, such as the elastomer. Instead, we wondered how we could do more with less by taking advantage of the fluid’s interaction with that material.”

Petersen’s team connected a series of elastomer bellows to thin tubes. This configuration allows for antagonistic movements – one that pulls and one that pushes. The tiny tubes induce viscosity, which distributes pressure unevenly, bending the actuator into different twists and patterns of movement. That would normally be a problem, but the team found a clever way to take advantage of it.

Researchers developed a fully descriptive model that could predict the possible movements of the actuator – all with a single fluid input. The result is an actuator that can perform much more complex movements, but without the multiple inputs and complex feedback control that previous methods required.

To demonstrate the technology, the team built a six-legged soft robot, topped with two syringe pumps, that walks at 0.05 body length per second and also crouches. But that’s just the beginning of the possible permutations.

“We’ve described the full range of methods that will allow you to design these actuators for future applications,” said Petersen. “For example, if the actuators are used as legs, we’re showing that by crossing just one set of tubes, you can go from an ostrich-like gait, which has a really broad stance, to an elephant-like trot.”

The new fluid-powered actuator can be used for various types of devices, such as robotic arms, and Petersen is interested in exploring how placing bellows in 3D configurations will result in still usable movement patterns.

“This is actually a whole new subfield of soft robotics,” she said. “Exploring that space will be super interesting.”

See this for more information Cornell Chronicle story.

Cornell University has dedicated television and audio studios available for media interviews.

Media Note: Video and a photo of the soft robot can be viewed and downloaded here:


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