Virginia Center for Autonomous Systems
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The Virginia Center for Autonomous Systems (VaCAS) is an ICTAS/College of Engineering research center which facilitates interdisciplinary research in autonomous systems technology. VaCAS hosts research activities spanning every application domain: water, land, air, and space. VaCAS member research activities range from fundamental control theory to vehicle development to applications for science, security, and commerce.
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http://www.unmanned.vt.edu/
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Browsing Virginia Center for Autonomous Systems by Content Type "Report"
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- Design and testing of a pneumatically propelled underwater glider for shallow waterWolek, Artur; Gode, Tejaswi; Woolsey, Craig A.; Quenzer, Jake; Morgansen, Kristi A. (Virginia Center for Autonomous Systems, 2015-10-28)This report details the design and testing of a pneumatically propelled underwater glider. The vehicle was designed as a platform for motion control experimentation, and to explore the use of novel actuator designs to improve performance in shallow water and significant currents. The glider’s pneumatic buoyancy engine is capable of rapidly inflating an elastomeric bladder to 5 liters. (This displacement is an order of magnitude greater than that of legacy buoyancy engine designs.) The buoyancy engine was shown to operate reliably at 25 m depth. However, the compressibility of the bladder and associated change in tank weight (from exhausting air with each dive) presented significant challenges in trimming the vehicle. The attitude of the glider is controlled by translating and rotating a semi-annular mass. Because of the geometry of this mechanism, the glider is not restricted to a range of roll attitudes (i.e. the glider has unlimited roll authority and can “flip over”). By flipping over the glider may employ asymmetric hydrodynamic surfaces while preserving the same flow-relative geometry during both descents and ascents. Such asymmetric hydrodynamic surfaces (e.g. cambered hydrofoils, dihedral, wing twist) may be used to improve efficiency and performance. The ability to operate in both upright and inverted orientations requires reducing the contribution of the rigid body (minus the moving mass) to the bottom heaviness of the vehicle. A moving acoustic long-baseline ranging system was developed to position the glider while it was underway. The performance of this system was characterized experimentally in terms of ping success rate for various transducer geometries and depths in a shallow-water, rocky bottom lake.
- Exploration of under-ice regions with ocean profiling agents (EUROPA)Allen, David W.; Jones, Matthew; McCue-Weil, Leigh S.; Woolsey, Craig A.; Moore, William B. (Virginia Center for Autonomous Systems, 2013-09-14)Europa is an incredibly enticing target for exploration – the nearest reaches of what may be a vast new "habitable zone" of interior oceans warmed and stirred by tidal forces. Decades of NASA and National Academy studies including the most recent planetary science decadal survey have affirmed the preeminence of Europa as a destination for astrobiology research. This report provides a comprehensive technology roadmap and an assessment of current state of the art and future technologies to enable an under-ice mission to Europa. In this study, the authors provide an overview of key mission objectives, a profile of Europa, and a mission overview. The authors then delve into a discussion of the key fundamental science objectives and design tradeoffs to arrive at a comprehensive science traceability matrix and value system for design of a multi-vehicle, under-ice mission to Europa. The current state of the art is assessed and design alternatives discussed. The report culminates in a concept of operations for the mission and a recommended mission architecture utilizing three surface units, each deploying a single cryobot, with each cryobot carrying three biologically inspired, gliding under-ice hydrobots equipped with sensor packages that will characterize the physical and chemical state of Europa’s ocean over its entire depth.
- User Manual for Bioflyer DatabaseAllen, David (2015-11-30)In order to compare the results of the new integrated morphology and gait optimization to diverse examples from biology, a comprehensive and easily accessible database is required. Unfortunately, no such database is publicly available, so one was developed. This database includes data from various sources. In addition, a text-based interface that utilizes MATLAB was developed that allows for easy access and editing the database. Additionally this interface can be used to create plots. These plots allow for the data to be sorted so that trends can be observed. These trends can be used to identify trends that form commonalities between diverse species as well trends that show difference between different fight strategies.