Most of our electronics, including PCs, smartphones, laptops, are cooled in some way due to the heat emitted from their integrated circuits, be it passive, fan, or water-cooling. Most robots, on the other hand, use passive heatsinks or fans to keep things cool while performing tasks. Engineers from Cornell University and Facebook Labs have now designed a robotic handle that is capable of sweating like humans to regulate its temperature, leading the way to high-powered robots that will be able to function for long periods without overheating.
T.J. Wallin, a research scientist at Facebook Labs, stated, “The ability to perspire is one of the most remarkable features of humans. Sweating takes advantage of evaporated water loss to rapidly dissipate heat and can cool below the ambient environmental temperature. So as is often the case, biology provided an excellent guide for us as engineers.” The team developed the sweaty robotic hand using finger-like actuators composed of two hydrogel materials capable of retaining water and responding to temperature.
The poly-N-isopropylacrylamide base layer reacts to temperatures above 860F by shrinking, which squeezes liquid from pressurized reservoirs filled with water that are connected to surface ducts made of heat-reactive plastic. The water is then released through micron-sized pores in a top layer of polyacrylamide. Those pores react to the same temperature as well and close when the temperature drops below 860F.
The evaporation of the water reduces the actuator's surface heat down to 700F in just 30-seconds, which is three times more efficient than our human bodies. When exposed to fan circulated air, those actuators can cool down six times faster than using water alone. More information on the sweat-capable robotic hand can be found in a recently released paper entitled “Autonomic perspiration in 3D-printed hydrogel actuators.”