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Researchers build a robot hand that cools itself with sweaty fingers

Robot hand
(Image credit: Shutterstock)

Researchers have developed a soft, robotic hand that can grip objects and ‘sweat’ when warm to cool itself down.

As explained in a paper published in Science Robotics, one of the biggest challenges for roboticists is keeping the temperature down, particularly when the robot is operating in warm environments.

Mechanical devices are never fully efficient, and some of their energy is always lost in the form of heat. They therefore need some kind of cooling system if they’re to operate for long periods without overheating and suffering damage.

For rigid devices, systems of fans and heat sinks are an ideal solution for dissipating heat, but they aren’t suitable for a device that needs to flex in all directions. That’s where sweat comes in.

When warm, human skin excretes sweat, which cools the body as it evaporates. It’s one of the reasons we’re such effective distance runners. The team of scientists (from Cornell University, Facebook Reality Labs, and Istituto Italiano di Technologia) aimed to replicate this effect with a ‘soft’ robot to see whether they could create the same effect, helping the bot run efficiently for longer.

The robot (a segmented, finger-like device) was 3D-printed using hydrogels, which are not unlike living tissue and can absorb large quantities of water. The body of the finger is made from a gel that expands at temperatures above 30C, with a layer of 'skin' on one side that shrinks at temperatures above 40C. Together, these properties cause the finger to bend around warm objects.

The ‘skin’ surface of the finger has pores that expand in warm temperatures to excrete pressurized liquid, and shrink when the material cools. The skin is also textured to give it a larger surface area, allowing for faster evaporation.

Cold finger

The researchers mounted several of the sweating fingers onto a rigid ‘palm’ to create a hand that could grip warm objects of different shapes and sizes, and discovered that the simulated sweating was even more effective at cooling the robot than human perspiration.

Interestingly, the fingers could even change the temperature of the objects they held; after retrieving a can from a warm water bath, the sweating reaction caused the metal to cool much faster than it would otherwise.

In future, ‘sweating’ could be used to allow robots to self-lubricate for smoother movement (think robot slugs) or excrete enzymes to ‘digest’ materials that they move over. The possibilities are fascinating – and just a little bit disgusting.

Via Spectrum IEEE