Water as ballast: worm robot WorMa shifts its weight for land and water
A robot from NYU Tandon pumps about 300 grams of water between its head and tail. This lets it climb steeper slopes and swim faster – without being rebuilt.
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Video: YouTube · NYU Tandon School of Engineering · youtube.com
Researchers at the NYU Tandon School of Engineering have built a worm-inspired amphibious robot that can shift its own centre of mass. WorMa – the name combines "worm" and "mass" – is about 50 centimetres long, weighs just over a kilogram and consists of five links with four joints. A pump in the middle section moves about 300 grams of water, 28 percent of its mass, between head and tail. The study was published in the journal Advanced Robotics Research.
With the water at the front, WorMa can climb slopes of up to 19.5 degrees that it otherwise cannot manage; according to the researchers, the cost of transport on the incline drops by at least 33 percent. With the water at the back, it swims up to 26 percent faster and 52 percent more efficiently. It also climbs steps up to 15 centimetres high. For now the weight shifting is controlled externally; the robot has no sensors for the terrain.
"The mechanism itself isn't tied to any one job," says Nana Obayashi, an assistant professor at NYU Tandon in whose lab WorMa was developed. Possible uses include environmental monitoring or infrastructure inspection. WorMa was first presented in September; a new report over the weekend has brought it back into focus.