Official News - page 8

REAL LIFE NEWS: POWERING THE UNDERWATER ROBOT FLEET

by Hazed

Oceanographers want to buiild a fleet of 100 robotic submarines to roam the vast unexplored stretches of the world's seafloors, but how will these underwater robots get their power? Batteries don't last long enough, and unlike the Mars rovers, they will not be able to get energy from the sun. If robot submarines are ever going to do what the scientists want them to do and undertake lengthy missions, they are going to need a new power source.

Two roboticists from the Bristol Robotics Laboratory in the UK might have the answer. They are developing a power source that harvests plankton from the ocean and together with dissolved oxygen in the water, turns it into power.

The Bristol team have in the past built a robot that was powered on dead flies called Ecobot. Its fuel cell contained anaerobic bacteria that were used to break down the flies' exoskeletons into sugars. This time, the sugar will come from breaking down plankton. The sugars are then metabolized by the bacteria which releases electrons.

In combination with the oxygen which is dissolved in water, this produces power. The fuel cell works like a pair of artificial gills to extract the oxygen from the water as it flows through them.

In tests using vinegar instead of plankton, the scientists have produced a current of just over 100 microamps. This wouldn't be enough for a robot that has to move all the time, but would be sufficient for one that just sat at the bottom of a river or the ocean until something happened - for example, it could watch for seismic activity or pollution. And who knows, the efficiency may improve with further experimentation.

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