(Credit:
Michigan State University)
Michigan State University researchers are spawning robot fish to monitor the quality of lake water and the effect of harmful algae.
The prototype fish resemble other robot fish, such as those being developed at MIT to check for pollutants in water.
An electric charge in the 9-inch MSU prototype causes its polymer fins to bend so the robotic perch can maneuver. Designs call for onboard sensors to record temperature, oxygen, pollutant, and algae data, which would be relayed to a docking station when the fish surfaces. GPS systems and infrared sensors could be developed to aid navigation.
The fish are designed to be low-cost for applications such as monitoring aquafarms and water reservoirs. Compared with water sampling by humans, the robo-fish would provide a more regular data feed by communicating with each other and their docking station.
The MSU researchers hope to make the robot more robust so it can swim through currents. Currently it can only move through calm water.
Postgraduate researcher Ryan Ladd helped develop Gymnobot at the University of Bath's Ocean Technologies Lab.
(Credit: Nic Delves-Broughton/University of Bath)A robot fish developed at the U.K.'s University of Bath features a unique method of propulsion--a single fin rippling along its belly like a wave. Bath engineers say Gymnobot might inspire lighter, more efficient robotic submersibles.
Recent robot fish, such as MIT's low-cost polymer fish, have flexible bodies, but Gymnobot is rigid save for a long undulating fin powered by twin crankshafts inside its body.
The design is a nod to freshwater knifefish, which can move forward and backward, and hover, by rippling an elongated ventral fin. The skin of the fin covers hundreds of fin rays that oscillate side-to-side, creating a wave in the water. Check out a black ghost knifefish moving here.
Other scientists have also examined this unique mechanism (PDF), though Bath engineers seem to be the first to build a model.
Gymnobot may be used to study biodiversity in oceans and rivers and help detect pollution. Its ventral fin would allow the robot to maneuver in shallower water than propeller-driven robots since propellers can get caught in reeds.
It may also be more energy-efficient, according to engineers at the University of Bath's Ocean Technologies Laboratory led by biomimetics lecturer William Megill.
The lab is also building a robot manta ray to study fish stocks in the fjords of British Columbia.
(Credit:
MIT)
On the heels of a scientific report last month saying 63 percent of world fish stocks require rebuilding, scientists at MIT have unveiled a new robot fish that's cheap to make and ripe for mass production.
Actually, MIT engineers Kamal Youcef-Toumi and Pablo Valdivia Y Alvarado aren't aiming to replenish fisheries. They want their robot swimmers to be used for underwater monitoring of pipelines, sunken ships, and pollution. Since the fish are less than a foot long, they can maneuver into spaces that are too tight for most underwater autonomous vehicles (UAVs).
The fish--while not as pretty as these toxin-sniffing robot carp patrolling Spanish waters--are notable for their novel design. They have fewer than 10 parts, making them low-cost, and are housed in a continuous flexible polymer casing that prevents water damage.
Lacking different segments, the fish can swim more naturally, according to MIT (watch the video after the jump). A single motor in the middle initiates a wave that moves along the body and propels it forward. Real fish move in a similar fashion by contracting muscles on either side of their bodies.
Youcef-Toumi noted that the polymers allow for stiffness to be specified in different sections, adding that another application would be robotic prosthetic limbs.
The early versions of the fish, about 5 inches long, swam like bass and trout, with movement concentrated in the tail. ... Read more
Propelled by a servo-actuated two-link tails and flapping pectoral fins, a new breed of robofish programmed to swim in schools may soon be used to track oil spills or wildlife such as whales, according to researchers at the University of Washington in Seattle.
By mimicking a fish's natural propulsion mechanics these "autonomous fin-actuated underwater vehicles" are able to swim in any direction, make tight turns, and even go backwards, researchers say. The university is testing three of the vehicles in an indoor freshwater tank equipped with a four-camera tracking system to supplement data collected by onboard sensors.
(Credit:
University of Washington)
One of their challenges is how to coordinate the artificial fish so that they work together. But radio signals don't travel well underwater, forcing robots in previous experiments to surface periodically to receive orders from central command or, worse, be being linked by cable.
These fish are more independent--controlling and coordinating their own actions using onboard microprocessor for collecting data and computing control commands, a pressure sensor for gauging depth, and a 3D compass all powered by NiMH rechargeable batteries. When they do need to communicate with one another, they use sonar-like "pings" from acoustic modems.
The three fish in this latest experiment kept it together despite losing roughly half of the information packets, which shows the system is relatively robust. "With a group of vehicles you can get more data collection at the same time than with just one. You get better spatial distribution and cover more area," Kristi Morgansen, a UW roboticist, told New Scientist.
The military thinks it's a good idea too. The U.S. Office of Naval Research wants to fund its own fishy version that would use cameras to gather data and then share the intel via sonar. Eh, herding whales sounds like more fun.
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