Soft Edible Robot: A Sweet Treat with a Purpose

While there are many useful questions to ask when meeting a new robot, “can I eat it” is usually not one of them. I say “in general” because Are edible robots a thing?— and not just edible in the sense that technically you could swallow them and get hurt. both benefits and consequencesBut ediblewhere you can take a big bite out of the robotchew and swallow.

Yum.

But for now, these edible robots come with a “please don't swallow” asterisk: a motor and battery that are definitely toxic and probably don't taste all that good. The problem was that the soft, easy to swallow drives operate under gas pressure, requiring pumps and valves to operate, none of which are easy to manufacture without plastic and metal. But in new documentresearchers from Dario Floreano Intelligent Systems Laboratory at EPFL in Switzerland showcased edible versions of both batteries and actuators, resulting in, to my knowledge, the first fully ingestible robot capable of controlled actuation.

EPFL

Let's start with this little guy's battery. In a broad sense, a battery is simply a system for storing and releasing energy. In the case of this particular robot, the battery is made of gelatin and wax. It stores chemical energy in chambers containing liquid citric acid and baking soda, which you can safely consume. The citric acid is separated from the baking soda by a membrane, and enough pressure on the chamber containing the acid will pierce this membrane, allowing the acid to slowly drip onto the baking soda. This activates the battery and starts generating CO.₂ gas along with sodium citrate (common in all types of foods, from cheese to sour candies) as a byproduct.

EPFL

CO2 gas passes through the gelatin tube into the actuator, which is a fairly common soft robotics design which uses interconnected gas chambers on top of a slightly stiffer base that flexes under pressure. Applying pressure to the actuator gives you one single actuation, but to get the actuator to wobble (wiggling is an absolutely essential skill for any robot), the gas must be released cyclically. The key to this is another important innovation: the swallowable valve.

EPFL

The valve operates on a snap-bend principle, which means it works best in one shape (closed), but if you apply enough pressure to it, it opens quickly and then closes again once the pressure is released. The current version of the robot runs at about four bending cycles per minute for a couple of minutes before the battery runs out.

And so: the battery, the valve and the drive, everything can be swallowed, and you get a small moving robot that can also be swallowed. Big! But Why?

“A potential use case for our system is providing food or medicine to elusive people. animals“Boars are attracted to live, moving prey, and in our case it's an edible drive that imitates it.” The idea is that you can get something like swine flu. vaccine in the robot. Because it is cheap to produce, safe to use, fully biodegradable, and mobile, it has the potential to serve as an effective strategy for targeted mass delivery to species that no one wants to go near. And apparently it's not just about wild boars: by customizing the robot's size and movement characteristics, what triggers it, and its smell and taste, you can target just about any animal that likes wiggling things. And that includes people!

Kwak says that if you ate the robot, the actuator and valve would taste a little sweet because they contain glycerin, and the texture would be like gummy candy. The air battery will be crispy on the outside and sour on the inside (like a lemon) thanks to the citric acid. Although this work does not focus specifically on flavor, the researchers have created other versions of the drive flavored with grenadine. They provided these drives to people earlier this yearand are working on “customer experience analytics,” which I can only assume is a requirement before announcing a partnership with Haribo.

However, edibility is not the robot's main goal, says PI. Dario Floreano. “If you look at it from a broader environmental and sustainability perspective roboticsThe pneumatic battery and valve system is a key technology as it is compatible with all types of biodegradable pneumatic robots.” And even if you are not particularly concerned about all environmental issues, and this really should be, in the context large flocks of robots in the wild It's critical to focus on simplicity and accessibility to be able to scale profitably.

It's all part of the EU funded RoboFood Projectand Kwak is currently working on others edible robots. For example, the elastic snap behavior in this robot's valve is similar to a battery in that it stores and releases elastic energy, and with some modifications, Kwak hopes that edible elastic energy sources could be the key to success. delicious little jumping robots that jump straight from the dessert plate into your mouth..

Edible pneumatic battery for long-term and repeated robot operationby Bokeon Kwak, Shuhang Zhang, Alexander Keller, Qiukai Qi, Jonathan Rossiter and Dario Floreano of EPFL, published in Cutting-edge science

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