This Robot Hand Cools Itself By Sweating

Sweating isn't exactly pleasant, but in terms of evolution, it's a useful tool to cool ourselves down naturally. Robotics have taken a leaf out of nature's book and made robots do the one thing we'd all rather not do: sweat.

via Tech Radar

All electronics have one major weakness: they cannot handle the heat. Cars, computers and mobile phones can all overheat, which is why they have built in cooling systems. But built-in fans aren't exactly flexible, so how will soft robots cool themselves while still being made from flexible, stretchy plastic instead of metal? The answer is sweat.
Researchers from Cornell University developed a soft robotic gripper that starts sweating when the temperature rises. Soft robots have many advantages (they're more durable and less likely to cause injury) but the polymer used to build them retains heat for longer periods than metals do. Being hotter than normal can also have an effect on the polymer's ability to bend, meaning that robot hands aren't able to grip things as well when they're hot. But sweating may help.
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via Scientific American

One of the main goals of robotics is to make robots as lifelike as possible, and although we would have thought that sweating is one of the traits they could have left out (I don't think anyone actually enjoys sweating - I definitely don't), it turns out that sweating is an extremely efficient method of cooling the body down. Mechanical cooling alternatives use very high levels of power. For example, marathon runners lose around 4 liters of sweat per hour, which equates to 2.5 kilowatts of cooling, while home refrigerators consume 1 kilowatt of energy for an hour of cooling.
To test their hypothesis, researchers printed a 'robot' (the segmented, finger-like device that looks like a jelly baby) using hydrogels, which are somewhat similar to living tissue and can absorb large quantities of water. One side of the finger is made from a gel that expands at temperatures above 30 degrees Celsius, and the other side is made from a material that shrinks at temperatures above 40 degrees Celsius. This combination makes the finger bend around warm objects.
The 'skin' of the finger also has pores that expand in warm temperatures and excrete pressurized liquid, and shrink when the 'skin' cools down.
via Scientific American

To test whether this simulated sweating is as good at cooling down as the real thing, the researchers put several 'fingers' onto a rigid 'palm' to create a hand that could grip warm objects of different shapes and sizes.
It turns out that the simulated sweating was even more effective than human perspiration, and the fingers could also change the temperature of the objects it held (making hot objects cooler). This finding could help to develop self-lubricating robots in the future (think robot slugs), and robots that sweat as much as you on a hot day. Not exactly pleasant, but then life isn't exactly pleasant. Doesn't get much more lifelike than that.