March 28, 2013
Robot Jellyfish Soon To Patrol Oceans
[ Watch the Video: Autonomous Robotic Jellyfish ]
Lee Rannals for redOrbit.com — Your Universe OnlineResearchers from Virginia Tech College of Engineering have created an autonomous robotic jellyfish the size and weight of a grown man.
Cyro is a larger model of a robotic jellyfish the team unveiled back in 2012 dubbed RoboJelly, which was about the size of a man's hand. The latest robotic ocean dweller is 5-foot-7-inches in length and weighs 170 pounds.
"A larger vehicle will allow for more payload, longer duration and longer range of operation," said Alex Villanueva of St-Jacques, New-Brunswick, Canada, and a doctoral student in mechanical engineering working under Shashank Priya, professor of mechanical engineering. "Biological and engineering results show that larger vehicles have a lower cost of transport, which is a metric used to determine how much energy is spent for traveling."
The robots are part of a nationwide $5 million project funded by US Naval Undersea Warfare Center and the Office of Naval Research. This project has a goal to place self-powering, autonomous machines in waters for surveillance purposes and monitoring the environment. They hope to utilize these machines to study aquatic life, map ocean floors, and monitor ocean currents.
Researchers chose jellyfish as the creature to mimic because of their ability to consume little energy. They also appear in a wide variety of shapes, sizes and colors, which allows for several designs.
Cryo is modeled after a jellyfish named Cyanea capillata. It is still in the prototype stage, and years away from being used properly.
"We hope to improve on this robot and reduce power consumption and improve swimming performance as well as better mimic the morphology of the natural jellyfish," Villanueva said. "Our hopes for Cyro's future is that it will help understand how the propulsion mechanism of such animal scales with size."
Cyro is powered by a rechargeable nickel metal hydride battery, compared to past robots which were tethered. The robot prototype is able to swim autonomously while maintaining a similar physical appearance and kinematics as the natural species.
"This autonomous operation in shallow water conditions is already a big step towards demonstrating the use of these creatures," said Shashank Priya, who headed the development of Cyro.
Cryo swims using electric motors that control the mechanical arms that are used in conjunction with an artificial mesoglea. Jellyfish in the wild use a diffused nerve net to control movement and perform complex functions.
The robot's skin is comprised of a thick layer of silicone, helping to mimic the sleek jellyfish skin. The skin is placed over a bowl-shaped device containing the electronic guts of the robot. When moving, the skin floats and moves along with the robot to look alive.
"It has been a great experience to finally realize the biomimetic and bio-inspired robotic vehicles," Priya said. "Nature has too many secrets and we were able to find some of them but many still remain. We hope to find a mechanism to continue on this journey and resolve the remaining puzzles."
Another robotic fish being worked on and written about earlier this month in the Proceedings of the Royal Society A has lateral line sensing capabilities. This robotic fish is able to understand the "flowscape" of water in order to move more efficiently.
“It is similar to reducing your effort in the tailwind of another cyclist or reducing the fuel consumption of your car by driving behind a truck,” said Prof. Maarja Kruusmaa, the Scientific Coordinator of the FILOSE project.