A new robotic fish may just fool you into believing it is a real animal. This strange, new aquatic robot is unique not just in the way it replicates realistic movements of fish, but also in basic engineering.
It is a member of a new generation of machines called soft robots. These designs use fluid flowing through flexible channels to drive the devices. Unlike mechanized devices with hinged bodies, the bodies of these soft robots can bend anywhere along their length, adding to flexibility and agility.
A long channel is built into either side of the robot fish's tail. When the on-board processor orders the fish to move, carbon dioxide from a canister located in the abdomen of the fish moves into one channel. That expands the artificial artery, pushing the tail in the opposite direction. By alternating the pressure on either side of the tail, the fish swims.
Andrew Marchese, a graduate student at the Massachusetts Institute of Technology (MIT), built the robotic fish. He was assisted by Daniela Rus and Cagdas Onal.
MIT researchers designed this new robot, which is the first autonomous soft robot able to execute rapid body movements. This can allow the machine to escape from traps or nets the same way a real fish would - by flopping around.
Dangers of a collision between a person and an automated machine are greatly reduced when using a soft robot.
"As robots penetrate the physical world and start interacting with people more and more, it's much easier to make robots safe if their bodies are so wonderfully soft that there's no danger if they whack you," Rus said.
Most current robots require the device to find paths for travel that do not collide with people or structures. Soft robots would be able to take more efficient routes.
During testing, Marchese noticed the angle at which the fish turned was determined by the duration of the gas burst. Turns could be as sharp as 100 degrees. Top speed for the fish was determined largely by the diameter of the nozzle employed. The performance of real fish behaves in much the same manner.
"To be honest, that's not something I designed for. I designed for it to look like a fish, but we got the same inherent parameter decoupling that real fish have," Marchese said.
One day, soft robots may be used to trail real fish. This could provide marine biologists a way of studying aquatic life with minimal distraction to the animals being studied.
The new aquatic robot is profiled in the premiere issue of the new science journal, Soft Robotics.
