Cornell researchers have discovered a novel – and delicious – way to power simple robots: Popcorn.

Because kernels expand rapidly and exert force when heated, the unpopped granules might provide just the right kind of boost for miniature jumping robots or edible devices ingested for medical procedures.

According to the Cornell team, the mix of kernels and lighter popped corn could someday even replace fluids in soft robots – without requiring components like air pumps or compressors.

“Pumps and compressors tend to be more expensive, and they add a lot of weight and expense to your robot,” said Steven Ceron, the paper’s lead author, in a recent university press release. “With popcorn, in some of the demonstrations that we showed, you just need to apply voltage to get the kernels to pop, so it would take all the bulky and expensive parts out of the robots.”

After studying popcorn’s properties using different types of heating, the researchers constructed three simple robotic actuators.

A soft robotic device powered by popcorn, constructed by researchers in Cornell’s Collective Embodied Intelligence Lab. (Image Credit: Cornell University)

Heating 36 kernels of popcorn with a nichrome wire, for example, created a jamming actuator that stiffened a flexible silicone beam.

Ceron and his popcorn colleagues also create a three-fingered soft gripper with kernel-stuffed silicone fingers. When the granules popped, the expansion exerted pressure against the outer walls of the fingers, causing them to curl.

To make an origami actuator, the team folded recycled Newman’s Own organic popcorn bags into origami bellows folds. The researchers demonstrated that the expansion of the kernels – via the microwave – had enough strength to support the weight of a nine-pound kettlebell.

So, will kernels play a role in tomorrow’s robots? Steve Ceron spoke with Tech Briefs about the power of popcorn.

Tech Briefs: Popcorn, of course, is a very unique technology component. What inspired this idea?

Steve Ceron: In the Collective Embodied Intelligence lab, we are interested in multi-functional designs that permit simple robots to achieve complex tasks. In this project, we are specifically looking for ways in which soft robot collectives can make impactful changes in the real world, for example by building amorphous structures inspired by the behavior in a multi-cellular slime mold. To do this, we need inexpensive fluids that can help a soft robot change rigidity and potentially expand upon deployment. Popcorn successfully demonstrates these features and is readily available at a very cheap price.

Tech Briefs: How does this technology work exactly?

Ceron: When the kernels pop, they expand many times their original size. If you, for example, surround the popcorn with a material that will stretch more on one side than the other, then you can get the overall actuator to bend in the direction that you would like. Using this approach, we were able to show grasping with a three-finger actuator.

To facilitate popping, the kernels are placed in a row and surrounded by a coil of Nichrome wire – basically toaster wire. When we pass a current through the wire, it heats up and passes that heat to the kernels. Once the kernels have heated up sufficiently, they pop, expand, and force the fingers to curl. We also showed how you can “pre-program” the expansion with a carefully folded bag of microwave popcorn, and how, using hot air, you can leverage the popping strength to pull tendons in a gripper with rigid links. Popcorn only pops once, of course, but if you want multiple runs, you can conceivably dissolve the kernels in water, then add new kernels, and repeat the process.

Tech Briefs: Beyond the fun aspect of the work, what does this accomplishment demonstrate about what’s possible with robotics and robotics applications?

Ceron: We envision using these multi-functional materials for jamming actuators, omitting the need for expensive and bulky pumps or compressors. The kernels pop, expand in size, interlock with each other, and jam to secure whatever object they are surrounding.

Tech Briefs: Generally, what is the value of minimalistic robots?

Ceron: Minimalistic robots allow for a large number of robots to be manufactured in a smaller amount of time. Each robot's sensing and actuation capabilities may be reduced; however, when all robots are actuated together, the collective motion have a grand effect.

Tech Briefs: What is most exciting to you about this research?

Ceron: The multi-functionality of the material. Popcorn is readily available, inexpensive, and drastically changes characteristics upon deployment. We just have to be a little extra creative in how we harness those benefits.

What do you think about popcorn-powered robots? Share your comments and questions below.