RESEARCH
Solar-powered AUV (SAUV II)
Upcoming 2007 SAUV II field tests
2004 - 2007 SAUV II field tests
Modular Mission Planning Toolkit (MMPT)
Development of Autonomous Vehicle Behaviors
Simulation and Virtualization
Gatekeeper Station-Keeping Buoy
A common programmatic theme underlies the research work performed at AUSI. This theme is best summarized by the goals of the Multiple Cooperating AUVs (MCAUV)
program, which are to evaluate a Long Endurance Mobile Underwater Coastal Surveillance System through a series of in-water demonstrations. In doing so, the MCAUV program seeks to move laboratory results from a range of preliminary AUV technologies into the open sea environment. These technologies focus on communication and cooperation among multiple heterogeneous AUVs; they include low-level underwater networking and high-level language protocols, cooperation strategies for adaptive sampling, and user interface issues inherent in AUV mission planning, monitoring and control. Key organizations include AUSI, Technology Systems, Inc. (TSI), Falmouth Scientific, Inc. (FSI), the Naval Undersea Warfare Center (NUWC)-Newport, University of New Hampshire (UNH) and Rensselaer Polytechnic Institute (RPI). Below are an overview to the programs and research topics currently being investigated, along with links to further information.
AUSI is currently developing and testing a Solar-powered Autonomous Underwater Vehicle (SAUV II) in partnership with FSI of Cataumet, MA and other members of the MCAUV team. The goal of this program is to develop an AUV system capable of autonomous underwater sampling with long endurance. SAUV II vehicles have been used in several in-water operations, demonstrating technologies including underwater networking and cooperative behavior. This program is funded by the Office of Naval Research.
Highly Accurate Temporal and Spatial Mapping of Coastal Regions Using Long Endurance AUVs
As part of this ONR-sponsored program, researchers from AUSI, the UNH Computer Science Dept. and RPI's Robotics and Automations Lab are investigating technologies required for communication and cooperation among multiple heterogeneous AUVs; they include low-level underwater networking and high-level language protocols, cooperation strategies for adaptive sampling, underwater navigation, and user interface issues inherent in AUV mission planning, monitoring and control. One of the enabling technologies we are currently focusing on is the design of a MAC layer collision handling mechanism which supports ranging as well as communication, while in parallel exploring network protocol designs which extend or replace the AUSNET and COFSNET designs. Testing of this MAC layer with ranging component will occur in simulation to be followed by field testing using the SAUV vehicles. Based upon these results, we plan to design, implement and test a merged MAC-layer/network-layer protocol with ability to support system level inputs (energy, navigation, mission) and support non-trivial gateway functionality such as packet type queuing and store-and-forward. This evolved protocol will provide the communications infrastructure necessary to allow platforms to communicate in an ad-hoc, peer-to-peer manner, while supporting the underlying navigation (ranging) requirement, and permit platform system inputs to optimize efficiency. See the paper Status Packet Deprecation and Store-Forward Routing in AUSNet presented at the First ACM International Workshop on UnderWater Networks (2006) for a discussion on some of these strategies for improved network performance.
AUSI is supporting TSI in the research and development of a Modular Mission Planning Toolkit (MMPT), the objective of which is to produce a mission planning capability that can be easily inserted into both existing and emerging shallow water and very shallow water operations. To ensure that a war fighter knows exactly what the environment is, the surf and near-shore ocean prediction models require accurate information about offshore winds, wave conditions, and bathymetry. AUVs must be able to collect this data, and as soon as possible, transmit this information back to the planner. The planner then needs to validate this data to ensure its accuracy, incorporate the data determined accurate into the model, and then update the fleet with new information gained. Multiple AUVs, operating cooperatively, can provide the most accurate environmental information and the proposed mission planner must be able to optimize the use of all AUV assets available. Experience gained during the AUVFest 2005 demonstration was incorporated into the design of the MMPT project. For example, MMPT is now being designed around a flexible database architecture and will incorporate an extremely modular interface. This will better support integration of future tools, such as mission editors which utilize behavior building blocks, as well as support links to forecast environmental data.
Researchers at AUSI and NUWC-Newport are working together to develop and test robot behaviors to support the creation of functionally robust mobile underwater vehicles. We are currently developing specifications for a set of behaviors, such as those which will support gateway functionality, a representative survey task, background navigation (including ranging), networked communications, and energy management. These will augment a set of cooperative behaviors already developed, including station-keeping, box and lawnmower survey behaviors. To support this research, we have developed a layered approach to creating and using behaviors. This approach is built upon the specification of an AUV Common Control Language (CCL), and includes the following layers:
See the paper A Common Control Language to Support Multiple Cooperating AUVS for a more complete discussion of this work.
AUSI researchers have augmented the Cooperative Autonomous Underwater Vehicle Development Concept (CADCON) environment to provide the capability to test and evaluate SAUV system components and multiple cooperative vehicle mission profiles before going in the water. This simulation facility allows for complete testing of SAUV onboard high-level software, including underwater networking protocol logic. The facility also has a training functionality in that top level mission planning and vehicle monitoring applications used by SAUV operators can also be tested as if they were in a field setting. Hardware components, such as radio frequency (RF) modems (typically connected to the vehicle monitoring application) as well as acoustic modems can also be tested within a systems context. The SAUV PC-104 system, running a Linux OS and the high-level software, can be tested as a bench-level component. In addition, significant portions of the standalone SAUV vehicle can be put into simulation mode, thereby allowing test of other on-board vehicle electronics and subsystems. This simulation facility was used to support behavior development and mission planning for both Lake George, NY (June 2006) and Monterey Bay, CA (July 2006) tests. For more information on this capability, see the Oceans 2006 conference paper A Simulation Environment for Testing and Evaluating Multiple Cooperating Solar-powered AUVs.
AUSI is supporting FSI, Vehicle Control Technologies, Inc. (VCT) and others to design, fabricate, and demonstrate a prototype Gatekeeper buoy system. The requirements of this buoy include: (1) SeaWeb Acoustic, RF, and satellite communications capability that is continuously available, (2) not tethered or anchored to the ocean bottom, (3) autonomous, but can be remotely accessed via communication systems, (4) maintains its station within some settable distance parameter (less than 1.5 kilometers, (5) endurance goal capability of operating unattended for about 3 to 4 months in ocean currents in the range of 1.5 knots and as long as possible in currents up to 3 knots, (6) easily deployed and retrieved, and (7) compatible with future design upgrades (air/submarine launched buoys).
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