Aerospace Engineering Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2737
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Item INERTIAL MOTION CAPTURE SYSTEM FOR BIOMECHANICAL ANALYSIS IN PRESSURE SUITS(2013) Di Capua, Massimiliano; Akin, David L; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)A non-invasive system has been developed at the University of Maryland Space System Laboratory with the goal of providing a new capability for quantifying the motion of the human inside a space suit. Based on an array of six microprocessors and eighteen microelectromechanical (MEMS) inertial measurement units (IMUs), the Body Pose Measurement System (BPMS) allows the monitoring of the kinematics of the suit occupant in an unobtrusive, self-contained, lightweight and compact fashion, without requiring any external equipment such as those necessary with modern optical motion capture systems. BPMS measures and stores the accelerations, angular rates and magnetic fields acting upon each IMU, which are mounted on the head, torso, and each segment of each limb. In order to convert the raw data into a more useful form, such as a set of body segment angles quantifying pose and motion, a series of geometrical models and a non-linear complimentary filter were implemented. The first portion of this works focuses on assessing system performance, which was measured by comparing the BPMS filtered data against rigid body angles measured through an external VICON optical motion capture system. This type of system is the industry standard, and is used here for independent measurement of body pose angles. By comparing the two sets of data, performance metrics such as BPMS system operational conditions, accuracy, and drift were evaluated and correlated against VICON data. After the system and models were verified and their capabilities and limitations assessed, a series of pressure suit evaluations were conducted. Three different pressure suits were used to identify the relationship between usable range of motion and internal suit pressure. In addition to addressing range of motion, a series of exploration tasks were also performed, recorded, and analysed in order to identify different motion patterns and trajectories as suit pressure is increased and overall suit mobility is reduced. The focus of these evaluations was to quantify the reduction in mobility when operating in any of the evaluated pressure suits. This data should be of value in defining new low cost alternatives for pressure suit performance verification and evaluation. This work demonstrates that the BPMS technology is a viable alternative or companion to optical motion capture; while BPMS is the first motion capture system that has been designed specifically to measure the kinematics of a human in a pressure suit, its capabilities are not constrained to just being a measurement tool. The last section of the manuscript is devoted to future possible uses for the system, with a specific focus on pressure suit applications such in the use of BPMS as a master control interface for robot teleoperation, as well as an input interface for future robotically augmented pressure suits.Item Augmented Reality for Space Applications(2008-08-08) Di Capua, Massimiliano; Akin, David L.; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Future space exploration will inevitably require astronauts to have a higher degree of autonomy in decision-making and contingency identification and resolution. Space robotics will eventually become a major aspect of this new challenge, therefore the ability to access digital information will become crucial for mission success. In order to give suited astronauts the ability to operate robots and access all necessary information for nominal operations and contingencies, this thesis proposes the introduction of In-Field-Of-View Head Mounted Display Systems in current Extravehicular Activity Spacesuits. The system will be capable of feeding task specific information on request, and through Augmented Reality technology, recognize and overlay information on the real world for error checking and status purposes. The system will increase the astronaut's overall situational awareness and nominal task accuracy, reducing execution time and human error risk. The aim of this system is to relieve astronauts of trivial cognitive workload, by guiding and checking on them in their operations. Secondary objectives of the system will be the introduction of electronic checklists, and the ability to display the status of the suit and surrounding systems as well as interaction capabilities. Features which could be introduced are endless due the nature of the system, allowing extreme flexibility and future evolution without major design changes. This work will focus on the preliminary design of an experimental Head Mounted Display and its testing for initial evaluation and comparison with existing information feed methods. The system will also be integrated and tested in the University of Maryland Space Systems Laboratory MX-2 experimental spacesuit analogue.