January 17, 2013
High-Tech Robotic Fish Glides Through Water With Great Ease
Lee Rannals for redOrbit.com — Your Universe Online
Scientists from the Michigan State University made a number of improvements on a high-tech robotic fish.
The new fish, called Grace, was designed and built by Xiaobo Tan, an MSU associate professor of electrical and computer engineering, and his team.
They equipped the new fish with an array of sensors, allowing it to travel autonomously through the water, as well as measure water temperature, quality and other pacts. These sensors could one day help to provide valuable data to scientists that could help clean up lakes and rivers.
The improvements also include giving the fish the ability to glide long distances practically indefinitely, using just a little amount of energy.
“Swimming requires constant flapping of the tail, which means the battery is constantly being discharged and typically wouldn´t last more than a few hours,” Tan said in a statement.
He noted that the disadvantage to gliding through the water is that it makes the fish slower, and less maneuverable.
“This is why we integrated both locomotion modes — gliding and swimming — in our robot,” said Tan. “Such integration also allows the robot to adapt to different environments, from shallow streams to deep lakes, from calm ponds to rivers, with rapid currents.”
The researchers enabled the robot to glide through a newly installed pump that pushes water in and out of the fish, depending on if they want the fish to ascend or descend.
Grace's battery pack sits on a kind of rail that moves backward and forward, in sync with the pumping action, allowing it to glide through the water with ease.
“She swam at three sites along the river and wirelessly sent back sensor readings,” Tan said. “I´m not sure, but we may have set a world record — demonstrating robotic fish-based sampling with commercial water-quality sensors in a real-world environment.”
Grace is different than other gliders because it is about 10 times smaller and lighter than a commercial underwater glider.
The research to develop Grace was supported by the National Science Foundation.