Robert S. Damus

A NEW PARADIGM FOR SHIP HULL INSPECTION USING A HOLONOMIC HOVER-CAPABLE AUV

The MIT Sea Grant AUV Lab, in association with Bluefin Robotics Corporation, has undertaken the task of designing a new autonomous underwater vehicle, a holonomic hover-capable robot capable of performing missions where an inspection capability similar to that of a remotely operated vehicle is the primary goal. One of the primary issues in this mode of operating AUVs is how the robot perceives its environment and thus navigates. The predominant methods for navigating in close proximity to large iron structures, which precludes accurate compass measurements, require the AUV to receive position information updates from an outside source, typically an acoustic LBL or USBL system. The new paradigm we present in this paper divorces the navigation routine from any absolute reference frame; motions are referenced directly to the hull. We argue that this technique offers some substantial benefits over the conventional approaches, and will present the current status of our project.

Design of an Inspection Class Autonomous Underwater Vehicle

Autonomous Underwater Vehicles (AUVs) have become ever more common in ocean science, military, and industrial applications. In particular, AUVs are becoming a significant option for undersea search and survey. Bottom following, tight turning radius, stability, and elimination of tow cables make AUVs appealing in this role. Recent commercial success has proven that AUVs can be competitive survey platforms. While AUVs that perform surveys have become more common and capable, there are few designed for close inspection tasks. These missions call for an AUV that can move slowly, on the order of 10-15 cm/sec, maneuver equally well in all three dimensions, and maintain a very stable orientation over the seafloor, usually for imaging and production of photo mosaics. The range and endurance requirements of an inspection class AUV are expected to be small compared to an AUV designed to survey large areas. The MIT AUV Lab is actively investigating the design of a new type of underwater vehicle, known as an Inspection Class AUV, for missions such as marine archaeology and fisheries habitat studies. Two new designs have been created, both of which are radical evolutions of existing Odyssey class vehicles. One design takes the proven subcomponents of the Odyssey II, namely the pressure spheres, sensors and actuators, and transfers them to an entirely new mechanical framework. The other design capitalizes on the modular nature of the Odyssey III vehicles and adds new modules that allow an Odyssey III to perform inspection tasks. This paper discusses the details of these new designs, their anticipated performance specifications and lessons learned from deployment of conventional Odyssey vehicles for inspections tasks.

Fisheries habitat survey with a small low cost AUV

Summary form only given. The AUV Xanthos was deployed in spring 2003 to demonstrate how the capabilities of autonomous underwater vehicles may be applied to the preservation and study of fisheries resources. Xanthos carries a low-light camera, LED illumination, and side scan sonar. The vehicles small size and robustness permit the use of a vessel of opportunity (a fishing trawler) to examine fisheries habitat. Surveys were conducted in protected zones and heavily fished areas, and the results compared.

A Wearable Vehicle Interface for augmented reality in operating AUVs

Running an operation with an autonomous underwater vehicle (AUV) presently requires that the pilots situate themselves, primarily in a sedentary position for extended periods of time, in front of a computer that is in communication with the vehicle. Such an operations workstation is likely to be a networked PC that cannot be exposed to the elements, but has access to all of the software necessary for data reduction and visualization. At the MIT AUV Lab we have extensive experience with this mode of operation. In order to overcome the deficiencies in the current paradigm, we have developed a lightweight computing system that is worn by members of the AUV deployment team to investigate the human factors issues associated with immersing a user in a computing environment that is being used to control an underwater robot. The wearable vehicle interface (WeVI) is intended for use in the marine environment and fits over a US Coast Guard approved personal flotation device. The WeVI provides for connectivity to the AUV as well as other WeVI suits via Radio Frequency and 802.11 b wireless standards. The operators point-of-view and GPS location may be shared among WeVI suits to promote situational awareness for the entire operations team. Mission control (planning, scripting, and launching), and visualizing datasets is performed through the graphical user interface that is displayed in a users head-mounted display. Research into particular attributes of the augmented reality provided by such a suit is ongoing and presented in this paper.