Popcorn Could Provide Biodegradable Robotic Actuators

Researchers from Cornell University have transformed a popular low-cost snack into a robotics part alternative.

Popcorn is one of the world's ultimate movie time snacks and fan favorite foods for sporting events. But could it become one of robotics newest go-to materials? A team of researchers seem to think so. 

In a study presented at this year's IEEE International Conference on Robotics and Automation, a team from Cornell University stuffed their robotics full of unpopped kernels of corn. Using a little bit of innovation, they discovered that unpopped kernels of popcorn doubled as pretty decent, cheap, single-use actuator alternatives. 

Heat gets applied to the popcorn, causing them to pop into its signature starchy consistency. This happens when the water trapped inside the kernel turns to steam and pops the exterior of the kernel's endosperm. The sudden drop in air pressure stops the endosperm from expanding as it cools in teh surrounding air. 

In a popcorn bag, it's a sound many are familiar with. However, inside a robotic system, the results can be a little different. The researchers tested extra small white kernels (the most cost efficient option available) and discovered they needed the kernels to become 15.7 times their original size. By strategically popping the kernels, the engineers could adjust the movement of the actuators. 

"We have thought of different possibilities, but one interesting demonstration would be a small robot that can hold a packed chamber of kernels," researcher Steven Ceron told IEEE over email. "The robot would be able to rapidly/locally heat a single kernel and push it out of the robot, simultaneously filling an open region with popped kernels and propelling the robot forward. We would be able to fill empty isolated spaces (maybe for thermal insulation, or added structural support) without having to open up the area."

The Cornell team presented their actuator solution at this year's ICRA where it garnered quite a bit of attention, Ceron said. 

"People were genuinely interested in the topic and what the possible applications of this novel robotic actuator could be," he noted. "It’s definitely the first work of its kind, so we really hope that it will motivate others to consider non-traditional materials, even something as random as popcorn, when developing new types of actuators and robotic devices."

The team isn't done working on these actuators just yet. Ceron, his advisor Kirstin Petersen, and the rest of the team are looking to perfect other biodegradable options for actuators that could provide eco-friendly and low-cost solutions to these robotics parts. 

"I did this work when I first arrived at Professor [Kirstin] Petersen’s lab, so I have been exploring different projects throughout the field," Ceron said. "I am switching gears now to study how we can leverage embodied intelligence and adaptability in soft robots to reduce the cost and control complexity required for a large robot collective."