Researchers from Virginia Tech and the University of Texas at Dallas, with funding from the Office of Naval Research, have created a self-sustaining robot with a silicone jellyfish design that fuels itself by absorbing hydrogen and oxygen from water. Consisting of two bell-like silicone structures powered by artificial “muscles,” the robot, nicknamed “Robojelly,” could perform perpetual underwater surveillance for the U.S. military.
Robojelly’s muscles consist of a nickel-titanium alloy wrapped in carbon nanotubes that are coated in platinum and housed within a pipe. The mixture of hydrogen and oxygen within the pipe creates heat and water vapor. Heat moves the robotic muscles, which in turn pumps out water and starts the cycle all over again. Robojelly’s propulsion is inspired by the real-life moon jellyfish, a common fixture in aquariums around the world.
“We’ve created an underwater robot that doesn’t need batteries or electricity,” said Dr. Yonas Tadesse, assistant professor of Mechanical Engineering at UT Dallas and lead author of the study. “The only waste released as it travels is more water.” In addition to running surveillance missions, Robojelly could check for pollutants in water and play a role in undersea rescue missions.
“The current design allows the jellyfish to flex its eight bell segments, each operated by a fuel-powered SMA (News - Alert) module. This should be sufficient for the jellyfish to lift itself up if all the bell segments are actuated,” Tadesse said. “We are now researching new ways to deliver the fuel into each segment so that each one can be controlled individually. This should allow the robot to be controlled and moved in different directions.” Currently, the robot only moves in a single direction.
Robojelly still needs some work. The propulsion system currently doesn’t produce enough power to keep itself from sinking, so the robot is still electrically powered in the lab. However, when the robot is fully functional and ready for naval deployment, drone Robojellys traveling through dangerous waters all over the world, such as the Persian Gulf, could provide crucial military intelligence without risking American lives.
The study by UT Dallas and Virginia Tech researchers was released in the journal Smart Materials and Structures.
Edited by Jennifer Russell