Aerospace Engineering Commons^™

Advanced Generalized Predictive Control And Its Application To Tiltrotor Aircraft For Stability Augmentation And Vibration Reduction, Thomas Glen Ivanco

Mechanical & Aerospace Engineering Theses & Dissertations

The goals of this research were to restore generalized predictive control (GPC) capability at NASA and within the community, to better understand GPC and its performance relative to other options, and to improve upon the capability of GPC. Unique to this research is the comparison of GPC with other control options including PID controllers, optimal control theory, and other versions of the similar AutoRegressive moving average model with eXogenous inputs (ARX) models. Similar to GPC, ARX models use an experimentally acquired system identification to characterize the input/output relationship between controls and response measurements. Because this relationship is determined from acquired …

Deep Learning Object-Based Detection Of Manufacturing Defects In X-Ray Inspection Imaging, Juan C. Parducci

Mechanical & Aerospace Engineering Theses & Dissertations

Current analysis of manufacturing defects in the production of rims and tires via x-ray inspection at an industry partner’s manufacturing plant requires that a quality control specialist visually inspect radiographic images for defects of varying sizes. For each sample, twelve radiographs are taken within 35 seconds. Some defects are very small in size and difficult to see (e.g., pinholes) whereas others are large and easily identifiable. Implementing this quality control practice across all products in its human-effort driven state is not feasible given the time constraint present for analysis.

This study aims to identify and develop an object detector capable …

Mechanics Of Preimpregnated Fiber Tow Deposition And Compaction, Virginia Meredith Rauch

Mechanical & Aerospace Engineering Theses & Dissertations

In additive manufacturing, such as Automated Fiber Placement (AFP), defects often develop during the deposition and compaction of preimpregnated composite material, which reduce the strength of the resultant material. It is necessary to reduce defects and have good adhesion between plies to optimize the laminate performance and reduce delamination between composite layers. The aim of this work is to study the adhesion and deformation of preimpregnated (prepreg) composite material during the deposition and compaction stage in the composite forming process and how material parameters can be used to increase laminate strength. Two types of experimentation were performed on thermoset IM7/8552 …

Implementation Of An Extended Kalman Filter Using Inertial Sensor Data For Uavs During Gps Denied Applications, Sky Seliquini

Mechanical & Aerospace Engineering Theses & Dissertations

Unmanned Aerial Vehicles (UAVs) are widely used across the industry and have a strong military application for defense. As UAVs become more accessible so does the increase of their applications, now being more limited by one’s imagination as opposed to the past where micro electric components were the limiting factor. Almost all of the applications require GPS or radio guidance. For more covert and longer range missions relying solely on GPS and radio is insufficient as the Unmanned Aerial System is vulnerable to malicious encounters like GPS Jamming and GPS Spoofing. For long range mission GPS denied environments are common …

Failure Mode, Effects And Criticality Analysis Of A Very Low Earth Orbit Cubesat Mission, Robb Christopher Borowicz

Mechanical & Aerospace Engineering Theses & Dissertations

When space programs launch vehicles into orbit, multiple failures could arise throughout the mission and corrective actions are often not an option. Applying reliability engineering approaches during the design phase focuses on analyzing risk by anticipating potential failures and mitigating uncertainties in the design. Old Dominion University, in partnership with the U.S. Coast Guard Academy, and the U.S. Air Force Institute of Technology designed and developed a 3U CubeSat mission to validate on-orbit, three space technology payloads. Mission SeaLion will fly as a secondary payload on stage two of Northrop Grumman’s Antares rocket and will be deployed in a very …

A Study Of Asymmetric Supersonic Wind Tunnel Nozzle Design, Brittany A. Davis

Mechanical & Aerospace Engineering Theses & Dissertations

Achieving higher Mach numbers for private and commercial flight is a growing interest in the aerospace community. To qualify vehicles prior to flight, tests must be run in wind tunnels. Asymmetric wind tunnel nozzles are of continuing interest to the aerospace community due to their ability to change throat geometry, allowing for a range of Mach numbers to be achieved that encompasses all of the supersonic regime. The sliding block wind tunnel at Old Dominion University (ODU) is designed for a range of Mach numbers from about 1.8 to 3.5 but is limited to an upper limit of 2.8 by …