Grace, which stands for “Gliding Robot ACE”, is a robotic fish designed and built by a team headed by Xiaobo Tan, MSU associate professor of electrical and computer engineering. Robofish Grace is equipped with an array of sensors that not only allow it to travel autonomously, but also measure water temperature, quality and other pertinent facts.
MSU scientists have made a number of improvements on the fish, including the ability to glide long distances, which is the most important change to date. The fish now has the ability to glide through the water practically indefinitely, using little to no energy, while gathering valuable data that can aid in the cleaning of our lakes and rivers.
“Swimming requires constant flapping of the tail,” Tan said, “which means the battery is constantly being discharged and typically wouldn’t last more than a few hours.”
The disadvantage to gliding, he said, is that it is slower and less maneuverable.
“This is why we integrated both locomotion modes – gliding and swimming – in our robot,” Tan said. “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 robot’s ability to glide is achieved through a newly installed pump that pushes water in and out of the fish, depending on if the scientists want the robot to ascend or descend. Also, the robot’s battery pack sits on a kind of rail that moves backward and forward, in sync with the pumping action, to allow the robot to glide through water on a desired path.
Technovelgy fans have been ready for this a number of years, because I can't resist robotic fish stories. It turns out that sf author Michael Swanwick described the Mitsubish robot turbot robofish in his 2002 short story Slow Life:
Black liquid flashed past the turbot’s infrared eyes. Straight away from the shore it swam, seeing nothing but flecks of paraffin, ice, and other suspended particulates as they loomed up before it and were swept away in the violence of its wake. A hundred meters out, it bounced a pulse of radar off the sea floor, then dove, seeking the depths...