Madeleine the Roboturtle

New Scientist reports that:

A robotic turtle could help engineers build better autonomous underwater vehicles and answer fundamental questions about how prehistoric beasts swam. The robot, called Madeleine, is already helping researchers understand when it is best to swim with four flippers and when to use two.

Madeleine (Editor's Note: that's the one on the LEFT) is similar in size and weight to a Kemp's Ridley or Olive Ridley sea turtle, measuring 80 x 30cm and weighing 24 kilograms. The robot also has a comparable power output, between 5 and 10 watts per kilogram, depending on how hard it is working.

The robot's polyurethane flippers have the same stiffness as a real turtle's, but are operated by electric motors connected to an onboard computer. These motors rotate each flipper so that its back lifts up, before rapidly sweeping it down again to generate propulsion. The robot is controlled remotely but has several sensors including video cameras, sonar and altimeter and accelerometer.

By imitating the design of a turtle, the researchers hope to build more efficient ocean robots.

But Madeleine could also help scientists understand why animals use their flippers in different ways. Sea turtles, sea lions and penguins, for example, all rely on one pair of flippers to propel themselves through the water, and use the other pair to steer. But the plesiosaurs and giant turtles that dominated Mesozoic seas – between 251 and 65 million years ago – apparently used all four flippers for power.

Long and colleagues used their robo-turtle and a swimming pool to experiment with different forms of flipper propulsion. They showed that four flippers are best for acceleration and stopping, while two flippers are more efficient for simply cruising along.

One important omission by the scientists was their failure to give Madeleine that all-important 'cute' factor... I mean, how difficult would it have been to paint some big, wide turtle eyes on 'her'? How do they expect Madeleine to get an appearance on Blue Peter without the 'Ahhh' factor?!
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