Robo-fish will soon be flexing their electro-active-polymer fins to perform critical environmental monitoring that safeguards our lakes, aqua farms and reservoirs.

Robotic fish are needed to monitor the quality of water in rivers, streams and lakes, according to Michigan State University researchers who have crafted artificial muscles to power them. Electro-active polymers use electrical signals from a microprocessor to activate artificial muscles that enable the robots to swim in a manner similar to natural fish. Watch a video showing how electrical engineer Xiaoba Tan is collaborating with zoologist Elema Litchman to design their robo-fish (click to watch).

"Fish are very efficient and highly maneuverable," said Tan, an assistant professor of electrical and computer engineering at Michigan State. "We want to build robots that can basically at least have similar capabilities."

Environmental monitoring today is limited to human inspectors, who must get in a boat, take water samples and then manually test them, a lengthy process that can only monitor conditions at a few times and locations. But robo-fish with on-board sensors could be assigned this task 24/7, permitting scientists to keep real-time track of water quality. Schools of robo-fish could operate autonomously, swimming to every part of a water body for months at a time, giving precise data on aquatic conditions and habitats. The team hopes the more detailed data sets will yield answers about the effects of climate change and other outside forces on our freshwater ecosystems.

"At first it was like science fiction, but I think it's going to become a reality," said Litchman, a Michigan State assistant professor of zoology. "Envision schools of fish that are outfitted with these diverse sensors, which is very exciting, since you can monitor temperature [and] oxygen distribution, and you can monitor concentrations of harmful algae."

Artificial muscles, instead of propellers and rudder, enable fish to maneuver in tight spaces without the risk of getting tangled up. Electro-active polymers are similar to real muscles in that electrical voltages can control ion movements that twist and bend the polymer, giving the robo-fish an electro-active central nervous system. Using a microprocessor as the nervous system's brain, signals are sent to fins fabricated from the electro-active polymers, allowing them to provide locomotion by flexing.

The team also plans to experiment with using the electro-active polymers in reverse by fabricating slender feelers that can aid maneuvering in tight quarters by sending signals back into the central nervous system when they touch nearby objects. Infrared sensors will be used as artificial eyes to avoid obstacles too. Global positioning systems will report the robo-fish's location at all times, and a wireless docking station will collect and report the data sets collected by the fish.

Funding has been provided by the National Science Foundation and the Office of Naval Research.