Scientists in South Korea have developed tiny robots that do not need batteries or an engine to power their movement. It is not perpetual motion, instead, the tiny robot runs on humidity from the environment around it, absorbing the moisture in their surroundings to be powered by water.
A new paper posted in Science Robots, the scientist from Seoul National University described the advantages of microrobots and how their 'Hygrobots' could increase their usage. Microbots can already assist people with having children and even pull cars, but these tiny bots are limited by the number of power sources that are available to them.
To solve this specific problem, the Korean team took an interdisciplinary approach. The paper's author includes Beomjune Shin of the SNU's department of mechanical and aerospace engineering as well as Gee Ho Parl of the school's program looking at stem cell biology.
"Most botanical movements are hydraulic in nature," the paper notes. The "simple transport of fluid (mostly water) in and out of the plant tissue generates motions." A great example of how water can create movement can be seen in straw wrappers that crinkle up with a few droplets of H20.
However, robots are more complex than straw wrappers, a robotic system needs to have some semblance of reliability and stability. The movement of the robot needs to be in the correct direction and should be accountable to some mathematical predictability.
The SNU team was able to build a Hygrobot that moves "spontaneously in a ratcheted fashion on a moist surface at a speed high enough to enable practical applications." It was achieved by building a frame out of fabricated hygroscopic PEO (polyethylene oxide) nanofibers that have different densities. They were also able to get their inchworm-style bot running through a variety of humidity levels thanks to the right nanofiber mixtures.
The Hygrobot is just going to keep getting better with time.