Researchers at the University of Southampton, Massachusetts Institute of Technology and the Singapore-MIT Alliance for Research and Technology have built a speedy, underwater robot modeled after an octopus. The robot features a 3D printed skeleton but has no moving parts or energy storage device, aside from its elastic outer hull.
First the robot fills with water, then it quickly deflates by shooting the water out behind it. The force of the backward moving water propels the robot forward. The 3D printed skeleton inside keeps the balloon tight and the final shape streamlined.
The researchers involved in the project say the propulsion system is unparalleled in terms of performance, when compared to other underwater robots. Recent tests show it can zip ten body lengths in less than a second.
“Human-made underwater vehicle are designed to be as streamlined as possible, but with the exception of torpedoes, which use massive amounts of propellant, none of these vehicles achieve speeds of even a single body length per second or accelerations of 0.1g, despite significant mechanical complexity,” saysDr Gabriel Weymouth, lecturer at University of Southampton and lead author of the study.
“Rigid bodies always lose energy to the surrounding water, but the rapidly shrinking form of the robot actually uses the water to help propel its ultra-fast escape, resulting in 53 per cent energy efficiency, which is better than the upper estimates for fast-starting fish.”
The researchers believe that making the robot bigger will further improve its performance.