The U.S. Office of Naval Research, which had initially invested $50,000 in the AUV Lab, was impressed enough by Odyssey to boost its backing to as much as $5 million annually. By the late 1990s, MIT had produced a fleet of 20 autonomous underwater vehicles. To meet the navy’s growing demand and serve an expanding client base, the AUV Lab spun off a company called Bluefin Robotics, which has become one of the leaders in the field. Today, oil companies use sonar-equipped Bluefin vehicles to survey the ocean floor, and the navy employs them to search for mines in potentially dangerous coastal waters.
The advantage of these AUVs is that they can cover large areas without constant monitoring–and they don’t require a large surface vessel to launch them, or trained operators on board to pilot them. They are programmed to head out on their own. An AUV engaged in surveying might be instructed to hit a series of waypoints, or underwater targets, in a given area. As it coasts, it relies on different instruments to estimate its position; it might use a GPS-based intelligent buoy-tracking system, for example, pinging acoustic beacons on the surface. Onboard navigation software uses the position estimates to determine whether the vehicle has remained on course and adjusts its heading if necessary. A scientist aboard a small vessel in the vicinity needs nothing more than a laptop to track data collected by the AUV.
As useful as AUVs have already proved in the real world, MIT engineers like Franz Hover, who runs the Odyssey IV project, are working hard at making them even smarter and more capable. MIT’s first three Odyssey-class vehicles are like sharks, in that they always have to be moving forward. That’s fine when you’re trying to survey the ocean floor, but it’s not so great when you want to stop and take a closer look.
Odyssey IV can really move–tests suggest it should be able to cruise underwater at about 2.5 meters per second–but just as important, it can stop. Four thrusters–two on either side, plus one each mounted on the bow and stern–enable the robot to turn in all directions, and to stay put when necessary.
The ability to hover could prove important for the marine-archaeology expeditions Chryssostomidis loves, since the vehicle could stay in place and study interesting objects instead of simply grabbing a sonar reading as it cruised past. It could also benefit energy companies that are currently assessing the feasibility of drilling wells far out in the Gulf of Mexico, beneath thousands of feet of water. Maintaining such wells will be tricky. Stop-and-go AUVs like Odyssey IV could cruise over a large area, perform close-up inspections, and monitor the wells for damage. In fact, from the AUV’s perspective such monitoring would be easier than exploring the vast ocean floor, because the wells themselves would provide reference points for the vessel’s high-powered Doppler velocity log. The DVL would bounce sound waves off the wellheads and pumps, just as it does with the walls of the Alumni Pool today. Then it would recapture those waves, calculate their Doppler shift, and derive the AUV’s velocity to estimate its position.