Principal Investigator Harold Hemond
Project Website http://auvlab.mit.edu/research/kemonaut/
Kemonaut is an Autonomous Underwater Vehicle based on the MIT Sea Grant Odyssey II design, incorporating a free flooding hull with three internal glass pressure sphere housings, allowing the NEREUS submersible membrane inlet mass spectrometer to be carried as payload in its forward bay. The vehicle-payload combination weighs approximately 200 kg in air and is designed for operation in freshwater and marine coastal environments to a depth of 300 meters. Composite structural components, including carbon fiber laminates and high-density structural foam, are used throughout the Kemonaut vehicle and NEREUS instrument to minimize weight while maintaining adequate strength and vehicle stability. Stability is further increased through asymmetric positioning of the glass pressure spheres relative to the vehicle centerline. This design permits greatly expanded vehicle payload capacity while preserving the Odyssey II hull shape and allowing for the use of existing propulsion and control systems.
Sea trials have successfully demonstrated the vehicle and instrument configuration's unique ability to autonomously measure multiple dissolved atmospheric gases at ambient concentrations throughout the water column. Applications particularly well suited for the Kemonaut-NEREUS configuration include pollution identification and mapping to aid in remediation efforts, assessment of sub-surface natural resources, and research on marine-related greenhouse gas cycling.
MIT Sea Grant's Odyssey Class autonomous underwater vehicles (AUVs) are small, easily deployable, low component cost survey platforms, which have been used in numerous missions throughout the world (Bellingham 1997). These vehicles make use of low-cost mass produced hollow glass spheres, which commonly function as full ocean depth floats, to house vehicle electronics, sensors and power systems in a dry one-atmosphere environment, thereby permitting the use of a free flooding vehicle hull and minimizing vehicle volume and displacement requirements. However, the minimization of vehicle displacement makes the tradeoff between range (i.e. power storage) and payload capacity a critical design consideration (Bellingham, Goudey et al. 1994). The NEREUS membrane inlet mass spectrometer, which is highly optimized to handle the difficult hotel function constraints imposed by small autonomous underwater vehicles, is completely self contained within an Odyssey compatible 17” glass pressure sphere, weighs 22 kilograms, and operates to depths of 100 meters on a self contained power supply, drawing less than 20 watts (Hemond and Camilli 2002). NEREUS uses an embedded autonomous control system capable of adapting its mission directives and sampling regimes to better monitor its environment. Operation of the NEREUS instrument onboard an autonomous underwater vehicle enhances the advantages of in-situ analysis of dissolved volatile chemicals by increasing the range and overall accessibility of data collection areas. Furthermore, unlike other platforms such as moorings, tow fish, and remotely operated vehicles, an AUV does not require a tether, thus allowing a spatial survey to be conducted faster, follow bathymetry better and operate in high sea states.
In August 2002, after having undergone successful limnologic and marine trials as both a buoyed and towed sensor, the NEREUS instrument was ready for integration into an Odyssey class AUV. At this time MIT Sea Grant's single remaining Odyssey II Xanthos vehicle used both of its internal pressure spheres to house vehicle power, control, and communication systems, making it physically impossible to accommodate the NEREUS instrument without consolidation of the components into a single sphere. NEREUS deployment aboard MIT Sea Grant's newer
Sea Grant's Odyssey Class autonomous underwater vehicles (AUVs) are small, easily deployable, low component cost survey platforms, which have been used in numerous missions throughout the world (Bellingham 1997). These vehicles make use of low-cost mass produced hollow glass spheres, which commonly function as full ocean depth floats, to house vehicle electronics, sensors and power systems in a dry one-atmosphere environment, thereby permitting the use of a free flooding vehicle hull and minimizing vehicle volume and displacement requirements. However, the minimization of vehicle displacement makes the tradeoff between range (i.e. power storage) and payload capacity a critical design consideration (Bellingham, Goudey et al. 1994). The NEREUS membrane inlet mass spectrometer, which is highly optimized to handle the difficult hotel function constraints imposed by small autonomous underwater vehicles, is completely self contained within an Odyssey compatible 17” glass pressure sphere, weighs 22 kilograms, and operates to depths of 100 meters on a self contained power supply, drawing less than 20 watts (Hemond and Camilli 2002). NEREUS uses an embedded autonomous control system capable of adapting its mission directives and sampling regimes to better monitor its environment. Operation of the NEREUS instrument onboard an autonomous underwater vehicle enhances the advantages of in-situ analysis of dissolved volatile chemicals by increasing the range and overall accessibility of data collection areas. Furthermore, unlike other platforms such as moorings, tow fish, and remotely operated vehicles, an AUV does not require a tether, thus allowing a spatial survey to be conducted faster, follow bathymetry better and operate in high sea states.
In August 2002, after having undergone successful limnologic and marine trials as both a buoyed and towed sensor, the NEREUS instrument was ready for integration into an Odyssey class AUV. At this time MIT Sea Grant's single remaining Odyssey II Xanthos vehicle used both of its internal pressure spheres to house vehicle power, control, and communication systems, making it physically impossible to accommodate the NEREUS instrument without consolidation of the components into a single sphere. NEREUS deployment aboard MIT Sea Grant's newer Odyssey III Caribou vehicle was unlikely until spring of 2003 because vehicle dynamics using a NEREUS payload section in combination with the vehicle's vectored thruster and MOOS operating system were not well understood and because delivery of a payload section from Bluefin Robotics was estimated to require several months.