Oct 17, 2016 | By Alec

Water and electronics – everyone knows it’s a disastrous combination. You drop a glass of water on your laptop once, and you’ll be careful for the rest of your life. And yet one Japanese robot thrives through exposure to water. Kengoro the human robot is equipped with a massive 108 motors to perform a wide range of functions, including pushups. But those engines can obviously overheat in minutes during such activities, so its Japanese developers have incorporated artificial veins in Kengoro’s 3D printed metal 'bones' that cool down the motors using de-ionized water.

This fantastic robotic breakthrough has come out of the laboratory of the University of Tokyo, and has just been presented at the IROS 2016 in Daejeon, South Korea. The robot was also showcased in the paper “Skeletal Structure with Artificial Perspiration for Cooling by Latent Heat for Musculoskeletal Humanoid Kengoro,” by Toyotaka Kozuki, Hirose Toshinori, Takuma Shirai, Shinsuke Nakashima, Yuki Asano, Yohei Kakiuchi, Kei Okada, and Masayuki Inaba.

As they explain, overheating is one of today’s biggest robotics challenges. Every motor generates heat, just like your laptop does, and especially encased spaces accommodating multiple motors can overheat very quickly. While some cooling systems (like fan-based solutions) already exist, most are neither efficient or cost-effective.

But in many ways, the human body is also packed with motors – called muscles. Humans also regularly need to dissipate excess heat, and we sweat to cool down our bodies. This water is pumped out all over our body and is a particular effective cooling method. Kengoro has therefore been outfitted with a similar system, though his ‘sweat’ evaporates from his mechanical bones in absence of a skin. As a result, he can do push-ups consecutively for 11 minutes without overheating, and a lot more, on less than a cup of water.

Aside from making robotics far more potent, this sweaty solution is also very efficient in terms of weight – unlike most other cooling methods which only increase bulk. And standing 1.7m tall and weighing 56kg already, Kengoro was already absolutely packed with hardware. The team led by professor Masayuki Inaba therefore opted to incorporate the cooling system inside Kengoro’s metal frame, ensuring that no additional weight was added.

But this solution goes a lot further than just adding some running water channels and setting up a circulatory system. Instead, the Japanese team incorporated a sweating technique that allows the water to seep out through the frame and onto the motors, cooling them through evaporation. Kengoro thus truly sweats. This was achieved by 3D printing Kengoro’s frame in aluminum powder, using a laser sintering 3D printer. This gives users full control over material density, allowing the researchers to vary the permeability of the metal in several crucial areas. The sponge-like structures surrounding the motors were thus covered with tiny gaps, allowing the water to seep through these microchannels – a solution that was only possible through 3D printing.

But it doesn’t end there, as these aluminum ‘bones’ actually include two porous layers: one in their core, and one nearer to the surface of the frame. As a result, the water slowly seeps outwards, resulting in an evaporating process that prevents water from dripping everywhere.

Thanks to this fantastically clever 3D printed aluminum frame, Kengoro is one of the most active robots around. With water as his fuel, he can run for half a day on a cup of de-ionized water – though the amount of necessary water depends on how hard he is working. Particularly draining exercises, such as push-ups, go through the water supply in just 11 minutes – still a fantastic achievement.

Tests have further shown that this cooling method is three times more effective than air cooling, and significantly better than a simple water circulation system as well. Traditional, bulky and very expensive active radiator cooling systems would still be more effective, but this 3D printing solution keeps Kengoro lighter and more efficient as well. “Usually the frame of a robot is only used to support forces,” lead author Toyotaka Kozuki revealed. “Our concept was adding more functions to the frame, using it to transfer water, release heat, and at the same time support forces.”



Posted in 3D Printing Application



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I.AM.Magic wrote at 10/20/2016 9:09:10 AM:

Creeepy face is made to scare people of robots :/

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