They may be slow on land, but when they're in the water, sea turtles are fast and maneuverable – qualities that are also desirable in underwater robots. Additionally, the robotic equivalent of a turtle's streamlined shell could be stuffed full of electronic components and batteries. It shouldn't come as a surprise, therefore, that both ETH Zurich and the ARROWS project have recently created their own turtle-bots. Now, the National University of Singapore has announced its own entry in the field, that can self-charge its batteries while at sea.

The turtle robot is being developed by a team led by Prof. S.K. Panda, which has previously created robotic fishes of various types.

Like a real turtle, it swims and executes sharp high-speed turns using selective paddling motions of its front and rear flippers. This form of locomotion also allows it to dive and ascend without taking on or releasing ballast. Because it doesn't require ballast tanks or pumps, it's subsequently smaller, lighter and more energy-efficient than it would be otherwise. That lack of a ballast system could alternately allow it to take on larger payloads than comparably-sized robots.

In order not to limit the duration of its missions to one charge of its battery pack, the robot is capable of recharging that pack by surfacing and utilizing integrated solar panels. The researchers tell us that it might also be able to generate battery-charging electricity by settling in one spot on the sea floor, then harnessing the power of underwater currents.

Such a system is already used by a spherical robot previously developed by the team – that robot sits in place as the passing water spins a set of built-in rotor blades, which are in turn attached to a dynamo-type generator.

Panda has suggested that applications for the turtle robot could include things like surveillance, detection of hazardous waste, and water quality monitoring. It could operate autonomously on solo missions, although it's also possible that schools of the robots could communicate with one another while collaborating on larger tasks.

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