Aerospace Engineering Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/2737

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Subject: search.filters.subject.Extravehicular Activity

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    ANALYSIS OF SCYE BEARING MOTION AS APPLICABLE TO THE DESIGN OF A MORPHING SPACESUIT
    (2011) Bradshaw, Heather; Akin, David L; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This thesis describes research supporting the development of the Morphing Upper Torso spacesuit design, which uses robotic augmentation of a rear-entry pressure suit to adjust torso dimensions. This concept has the potential to provide increased mobility, easier ingress/egress of the suit, and reduced astronaut workload during extravehicular operations. A range of motion study has been conducted in which subjects wore simulated shoulder scye bearings while performing selected tasks, with the intent to measure human motion in relation to scye bearing motion. Results of the study include an investigation of the neutral pose of the scye bearings in Earth gravity, an analysis of the angular range of motion observed for the right scye bearing, and the development of a heuristic model to predict scye bearing position and orientation as a function of known arm pose.
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    Pressure-Constrained, Reduced-DOF, Interconnected Parallel Manipulators with Applications to Space Suit Design
    (2009) Jacobs, Shane Earl; Akin, David L; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This dissertation presents the concept of a Morphing Upper Torso, an innovative pressure suit design that incorporates robotic elements to enable a resizable, highly mobile and easy to don/doff spacesuit. The torso is modeled as a system of interconnected, pressure-constrained, reduced-DOF, wire-actuated parallel manipulators, that enable the dimensions of the suit to be reconfigured to match the wearer. The kinematics, dynamics and control of wire-actuated manipulators are derived and simulated, along with the Jacobian transforms, which relate the total twist vector of the system to the vector of actuator velocities. Tools are developed that allow calculation of the workspace for both single and interconnected reduced-DOF robots of this type, using knowledge of the link lengths. The forward kinematics and statics equations are combined and solved to produce the pose of the platforms along with the link tensions. These tools allow analysis of the full Morphing Upper Torso design, in which the back hatch of a rear-entry torso is interconnected with the waist ring, helmet ring and two scye bearings. Half-scale and full-scale experimental models are used along with analytical models to examine the feasibility of this novel space suit concept. The analytical and experimental results demonstrate that the torso could be expanded to facilitate donning and doffing, and then contracted to match different wearer's body dimensions. Using the system of interconnected parallel manipulators, suit components can be accurately repositioned to different desired configurations. The demonstrated feasibility of the Morphing Upper Torso concept makes it an exciting candidate for inclusion in a future planetary suit architecture.
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    Investigation of a Cable-Driven Parallel Mechanism for Pressure Suit Arm Resizing and Motion Assistance
    (2007-07-19) Benson, Elizabeth; Akin, David; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The fit of a spacesuit has been identified as a crucial factor that will determine its usability. Therefore, because one-size-fits-all spacesuits seldom fit any wearer well, and because individually tailored spacesuits are costly, the University of Maryland has conducted research into a resizable Extravehicular Activity (EVA) suit. This resizing is accomplished through a series of cable-driven parallel manipulators, which are used to adjust the distance between plates and rings built into a soft space suit. These actuators, as well as enabling passive suit resizing, could be used to actively assist the astronaut's motion, decreasing the torques that must be applied for movement in a pressurized suit. This thesis details the development and testing of an arm test section, which is used to better understand the dynamics of a more complex torso-limb system.