Edible robots could be on the menu, with Swiss engineers from École Polytechnique Fédérale de Lausanne (EPFL) reporting on their creation of a fully edible pneumatic actuator.
Made from a mix of gelatin, glycerin and water, the edible actuator is fabricated via a moulding process. It measures 90 mm by 20 mm by 17 mm. Despite being made of ingestible material, it has mechanical characteristics like those of silicone elastomers. This allows the actuator to have a bending angle of 170.3 degrees, and a blocked force of 0.34 N when 25 kPa of pressure is applied.
Like any other elastomer based pneumatic actuator, two actuators can be integrated to form a gripper able to handle various objects.
The grip has been tested, with the researchers adjusting the actuated force so as to grasp objects of different sizes and shapes, including an apple, a boiled egg, an orange, a Lego brick, and a bottle of chewing gum.
According to the engineers, the edible actuator could in the future be combined with other recent developments in edible materials and electronics, such as edible transistors, sensors, batteries, electrodes and capacitors.
The team pointed out that there has been very limited use of edible materials in robotics actuators thus far. Other researchers have developed a gelatin hydrogel actuator immersed in sodium hydroxide solution, and an ingestible robot that uses intestines of pigs as folding parts, but both require external electric and magnetic fields to work. In contrast, pneumatic soft actuators have already been widely developed and applied to robotic applications. They also benefit from a simple structure that can be extended to form a robot itself.
One possible result of the addition of edible actuators means in the future, miniaturised edible robots could be swallowed whole, execute their function in the body, then simply be digested without having to retrieve them.
“The components of such edible robots could be mixed with nutrient or pharmaceutical components for digestion and metabolisation,” they stated in their research paper.
“Potential applications are disposable robots for exploration, digestible robots for medical purposes in humans and animals, and food transportation where the robot does not require additional payload because the robot is the food.”
[Photo:EPFL]