Robot school takes to sea

Later this month in

, an entire fleet of undersea robots will for the first time work together without the aid of humans to make detailed and efficient observations of the ocean.

The oceanographic test bed in Monterey is expected to yield rich information in particular about a periodic upwelling of cold water that occurs at this time of year near Point Año Nuevo, northwest of Monterey Bay.

The project may also lead to the development of robot fleets that forecast ocean conditions and better protect endangered marine animals, track oil spills, and guide military operations at sea. The mathematical system that allows the undersea robots to self-choreograph their movements in response to their environment might one day power other robotic teams that, without human supervision, could explore not just oceans, but deserts, rain forests or other planets.

The August field experiment is the centerpiece of a three-year program known as Adaptive Sampling and Prediction (ASAP), which is funded by the US Office of Naval Research.

During the experiment, the ASAP system will determine what paths the underwater robots should follow to take the most information-rich samples, or measurements, of ocean activity. As the ocean changes, automated computer programs will update the sampling strategy under the supervision of the ASAP team. Most of the scientists will not be on site during the actual field experiment. The team will collaborate while the experiment is ongoing through a virtual control room. The researchers will gather online in the virtual control room to share observations and make decisions about necessary changes to the field operation as it is under way.

The underwater robots, known as gliders, will take the ocean's temperature, measure its salinity, estimate the currents and track the upwelling. Two types of gliders will be deployed -- Spray gliders and Slocum gliders. The Slocum gliders belong to David Fratantoni of the Woods Hole Oceanographic Institution; the Spray gliders to Russ Davis of the Scripps Institution of Oceanography.

In contrast to typical ocean-observing systems, which are static, the mobility of the gliders allows them to capture the dynamic nature of the ocean, which is always shifting in time and space. Furthermore, the gliders will be coordinated onto patterns to ensure that as they move, the measurements they take are as information-rich as possible.

Inspired by the behavior of schools of fish, Naomi Ehrich Leonard's group at Princeton University has created algorithms that allow the gliders to self-choreograph their movements in a series of rectangular patterns. The patterns span a large volume that the scientists have mapped in Monterey Bay.

On a day-to-day basis the control algorithms allow the gliders to make decisions independently about how to alter their course -- without any input from humans. This day-to-day autonomy enables the gliders to move according to the organized patterns, even as they are buffeted by strong currents.