Underwater robots, otherwise known as autonomous underwater vehicles, or AUVs, have been exploring the ocean floor for years, documenting species and habitats and monitoring changes to the seabed, but there are spots in the ocean that are too hazardous even for robots. Deep ravines, steeply dropping canyons and other major obstacles have so far been too much for AUVs to navigate, but thanks to a new software system, that's all about to change.
Stanford University explains, "Photographing the ocean floor with underwater vehicles isn't new, but the software system developed by Sarah Houts, a doctoral candidate in Stanford's Aerospace Robotics Laboratory, would for the first time allow vehicles to autonomously image twisting ravines and other hazardous topographical features. Until now, scientists could image these tricky spaces only by remotely steering a vehicle themselves from aboard a ship, an expensive, impractical operation for missions involving periodic monitoring of the seabed."
The new software builds on the TRN (terrain-relative navigation) system built by engineer Rob McEwen that lets an underwater vehicles know its location by matching its distance above the ocean floor to an existing terrain map. Stanford University says based on the terrain maps, "Houts calculated the optimal trajectories, as well as the vehicle's optimal altitude, speed and orientation at each point along the flight path, allowing the AUV to safely fly close to the ocean floor. The autonomous craft applies algorithms to steer itself around obstructions in its path."
The system was put to the test in Monterrey Bay where they had an AUV fly over a cliff at a constant altitude just to ensure it understood the commands. Next up, the researchers will program in the algorithms and see if the AUV is able to navigate based on them.
They expect to be running missions with the new system by next year, including monitoring the sea floor for effects of bottom trawling and climate change. They also plan on adapting the system to monitor movement and change in icebergs, where the AUV would not only take photos but samples of the iceberg for study. In general, Houts and her team hope the technology leads to even smarter vehicles for scientific research.
"The goal is to be able to do this without a map and just take measurements ahead of you in the terrain and fit a trajectory to that," Houts said.