July 16, 2012      

Part of an emerging generation of soft materials robots, autonomous RoboJelly systems are being designed to swim in waters worldwide and accomplish a variety of different critical tasks, from spotting pirates to monitoring water quality. Featuring a synthetic, rubbery skin that covers a bowl-shaped device crammed with electronics, RoboJelly systems are self powered. Taking a cue from nature, the systems run on a renewable energy source?hydrogen scooped directly from the water. “The robots will be able to operate on their own for several months,” says Shashank Priya, an associate professor of mechanical engineering and materials science at Virginia Tech. “The approach will eliminate the need to find and retrieve a tiny robot in a vast ocean to simply replace its power source.” Diverse Configurations Virginia Tech researchers are currently working on several RoboJelly models in various shapes and sizes?ranging from just a few inches across to a system that measures over five-feet wide?to discover optimal configurations for various types of tasks. Beyond pirate detection and water quality monitoring, researchers envision a wide array of potential applications, including ocean floor mapping, current monitoring, sea life migration tracking and oil spill cleanup support. The robots’ propulsion mechanism is also designed to imitate nature. Project researchers are currently investigating two motive forces used by real-life jellyfish: rowing and jet propulsion. ?Our biologists have been studying dozens of jellyfish species,” Priya says. ?We are investigating both propulsion mechanisms for their suitability in different potential applications.? Several characteristics make jellyfish a good robotic model, including a low metabolic rate that enables them to consume relatively little energy. “They can also live in many different types of water conditions and have a shape that’s suitable for carrying a payload,” Priya observes. He adds that jellyfish inhabit all of the planet’s major oceanic areas, can tolerate a wide range of temperatures and thrive in both in fresh and salt water environments. While jellyfish are most commonly found in shallow coastal waters, some have been discovered in depths up to 7,000 meters below sea level.?

Military Roots The U.S. Naval Undersea Warfare Center and the Office of Naval Research were the first organizations to target jellyfish as a design model for underwater robots. Four years ago, Virginia Tech joined with four U.S. universities on a multi-year, $5 million project funded by the naval institutions that divides research responsibilities among the various partners. Priya notes that robotic jellyfish development requires an interdisciplinary research approach that includes the efforts of materials scientists, mechanical engineers, biologists, chemists, physicists, electrical engineers and ocean engineers. Virginia Tech is currently building RoboJelly body prototypes and developing control systems. The University of Texas at Dallas is researching nanotechnology-based actuators and sensors. Providence College in Rhode Island is studying biological issues. The University of California/Los Angeles is developing electrostatic and optical sensing/controls while Stanford University is conducting chemical and pressure sensing research. Several other major U.S. universities and companies are also participating in the project as collaborators and/or advisory board members. Additional Research At least several more years of intensive research will be needed before robotic jellyfish can begin routine sea patrols. Beyond work on the robots themselves, engineers in various fields will have to design and test cameras, sensors, communications devices and other sub-systems necessary for control and research activities. Priya believes that of this work will lead to a substantial payoff. “It?s very exciting when everything comes together and we can create experimental models that can surpass millions of years of evolution,” he says.