The new development is in the form of a soft robot muscle which is capable of regulating its temperature through a function that is analogous to sweating.
The Cornell University research is based on the concept of thermal management, to devise robots that are mobile and high-powered, and which can operate for extended periods of time without overheating.
This is important in extreme environments, such as areas of high heat, since without the capability to manage a robots’ internal temperature, high-torque density motors and exothermic engines could trigger overheating, rendering the robot non-functional.
Researcher T.J. Wallin discusses the inspiration behind the experiment, which was inspired by human biology: “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 cooling functionality was achieved by the use of nanopolymer materials. These materials were generated by a special type of 3D-printing technique termed multi-material stereolithography. This additive manufacturing process uses light to cure resin into predesigned shapes.
The printing process enabled the scientists to construct finger-like actuators made up of two hydrogel materials that can retain water and respond to temperature (a type of “smart” sponge). The base layer responds to temperatures above 30 C (86 F) by shrinking. This activity squeezes water up into a top layer of perforated with micron-sized pores.
The pores are sensitive to the same temperature range and automatically dilate to release the “sweat,” then close when the temperature drops below 30 C and this cools down the robot.
The development has been reported to the publication Science Robotics, where the research paper is titled “Autonomic perspiration in 3D-printed hydrogel actuators.”
