Adaptive Control For A Class Of Nonlinear, Time Varying Rotational Systems,
2024
Embry-Riddle Aeronautical University
Adaptive Control For A Class Of Nonlinear, Time Varying Rotational Systems, John Zelina
Doctoral Dissertations and Master's Theses
Aerospace systems often exhibit nonlinear, time varying dynamics. Expansive mission profiles, fuel burn or transfer and payload deployments or slung loads can supply additional complexity that can excite the plant dynamics and result in undesirable performance. Because of these often unknown dynamical effects in aerospace systems, an emphasis is placed on controller robustness as significant safety risks are present. Due to the difficulty of predicting uncertainties, robust control can be achieved in two distinct ways. The first approach is to design a control law to be tolerant to a large amount of uncertainty, and the second is to design a …
Benchmarking Of A Sco2 Heat Exchanger Flow Loop,
2024
Embry-Riddle Aeronautical University
Benchmarking Of A Sco2 Heat Exchanger Flow Loop, David Velasco
Doctoral Dissertations and Master's Theses
Heat transfer of supercritical carbon dioxide (sCO2) was studied experimentally by commissioning a sCO2 flow loop featuring a horizontal tube-in-tube counterflow heat exchanger with a circular cross section. The main objective was to establish experimental heat transfer research capabilities for sCO2 at Embry-Riddle Aeronautical University’s (ERAU) Thermal Science Lab. sCO2 experiences a drastic change in thermophysical properties near its critical point that results in unique heat transfer characteristics. The high pressures at which sCO2 exists make the large gradients in thermophysical and transport properties difficult to study, experimentally and numerically. However, understanding the heat transfer characteristics and thermophysical behavior of …
State Omniscience For Cooperative Local Catalog Maintenance Of Close Proximity Satellite Systems,
2024
Embry-Riddle Aeronautical University
State Omniscience For Cooperative Local Catalog Maintenance Of Close Proximity Satellite Systems, Chris Hays
Doctoral Dissertations and Master's Theses
Resiliency in multi-agent system navigation is reliant on the inherent ability of the system to withstand, overcome, or recover from adverse conditions and disturbances. In large part, resiliency is achieved through reducing the impact of critical failure points to the success and/or performance of the system. In this view, decentralized multi-agent architectures have become an attractive solution for multi-agent navigation, but decentralized architectures place the burden of information acquisition directly on the agents themselves. In fact, the design of distributed estimators has been a growing interest to enable complex multi-sensor/multi-agent tasks. In such scenarios, it is important that each local …
Initial Orbit Determination Of Uncooperative Satellites Using Particle Swarm Optimization From The Point Of View Of A Novel Observer Orbit,
2024
Embry-Riddle Aeronautical University
Initial Orbit Determination Of Uncooperative Satellites Using Particle Swarm Optimization From The Point Of View Of A Novel Observer Orbit, Taylor Yow
Doctoral Dissertations and Master's Theses
Initial orbit determination is an incredibly valuable tool in the field of space situational awareness (SSA). As the number of launches increases every year, more objects are being put into space around the Earth and with political tensions mounting between certain space-accessing countries such as the United States of America (USA), Russia, and China, the number of satellites whose orbits are unknown to a political rival are increasing as well. In this research, orbit estimation of uncooperative target satellites from the point of view of novel orbits using particle swarm optimization (PSO) algorithm is explored. Two cost functions for the …
Trustable Adaptive Controllers For Multi-Agent Systems With Actuator Dynamics,
2024
Embry-Riddle Aeronautical University
Trustable Adaptive Controllers For Multi-Agent Systems With Actuator Dynamics, Atahan Kurttisi
Doctoral Dissertations and Master's Theses
Multi-agent systems have become a powerful tool for a wide range of applications due to the effective and cheap solutions they offer. Especially during the last decade, they have impacted a wide array of civilian and military applications (e.g., surveillance, reconnaissance, and payload transportation). However, they suffer system anomalies due to the operational and material conditions, which yields degraded performance or even instability. Hence, this dissertation investigates the distributed adaptive control design process for uncertain multi-agent systems with scalar and high-order dynamics in the presence of unknown control effectiveness and actuator dynamics. First, it provides an approach for driving a …
A Comparison Of Beamforming Characteristics In Isotropic And Composite Plate Structures For Use In Structural Health Monitoring,
2024
Embry-Riddle Aeronautical University
A Comparison Of Beamforming Characteristics In Isotropic And Composite Plate Structures For Use In Structural Health Monitoring, Sarah Ketchersid
Doctoral Dissertations and Master's Theses
Structural health monitoring in plate-like simple structures using phased array beamsteering of guided Lamb waves is useful in damage detection and evaluation efforts. Lamb waves can be effectively used for beamsteering using a linear array. The experimentation primarily focuses on beamsteering in the aluminum panel, which involves developing a simulation based on extracted data to visualize the dispersion of waves across the panel. By evaluating parameters such as slowness, velocity, and amplitude direction and variation for a specific metallic plate, the wavefront generated by a single wave source can be represented as a function of propagation angle and distance from …
Understanding Lightning Damage Formation In A Carbon-Epoxy Pultruded Rod Stitched Efficient Unitized Structure (Prseus) Composite,
2024
Texas A&M University
Understanding Lightning Damage Formation In A Carbon-Epoxy Pultruded Rod Stitched Efficient Unitized Structure (Prseus) Composite, Dounia Boushab, Aniket Mote, Khari Harrison, Juhyeong Lee, Charles U. Pittman Jr., Thomas E. Lacy Jr.
Mechanical and Aerospace Engineering Faculty Publications
Lightning damage to composite aircraft structures results from a concurrent and sequential interaction between arc discharge multi-physics and the anisotropic electrical and thermal composite properties. In this study, the impact of nominal 50 and 125 kA lightning strikes on damage formation in a carbon-epoxy Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) was investigated. A combination of visual inspection, ultrasonic phased array testing, destructive sectioning, and various microscopy techniques was employed to characterize the damage. Localized damage, including severe matrix decomposition, melting of polyester warp-knitting yarns, fiber splitting, and large-scale delamination, was confined to the immediate vicinity of the lightning attachment …
A Machine Learning Model Of Perturb-Seq Data For Use In Space Flight Gene Expression Profile Analysis,
2024
Purdue University
A Machine Learning Model Of Perturb-Seq Data For Use In Space Flight Gene Expression Profile Analysis, Liam F. Johnson, James Casaletto, Lauren Sanders, Sylvain Costes
Graduate Industrial Research Symposium
The genetic perturbations caused by spaceflight on biological systems tend to have a system-wide effect which is often difficult to deconvolute it into individual signals with specific points of origin. Single cell multi-omic data can provide a profile of the perturbational effects, but does not necessarily indicate the initial point of interference within the network. The objective of this project is to take advantage of large scale and genome-wide perturbational datasets by using them to train a tuned machine learning model that is capable of predicting the effects of unseen perturbations in new data. Perturb-Seq datasets are large libraries of …
Farmer Perceptions Of Land Cover Classification Of Uas Imagery Of Coffee Agroecosystems In Puerto Rico,
2024
Embry-Riddle Aeronautical University
Farmer Perceptions Of Land Cover Classification Of Uas Imagery Of Coffee Agroecosystems In Puerto Rico, Jose Cabrera, Blake Neal, Kevin Adkins, Ronny Schroeder, Gwendolyn Klenke, Shannon Brines, Nayethzi Hernandez, Kevin Li, Riley Glancy, Ivette Perfecto
Publications
Highly diverse agroecosystems are increasingly of interest as the realization of farms’ invaluable ecosystem services grows. Simultaneously there has been an increased use of uncrewed aerial systems (UAS) in remote sensing as drones offer a finer spatial resolution and faster revisit rate than traditional satellites. With the combined utility of UAS and the attention on agroecosystems, there exists an opportunity to assess UAS practicality in highly biodiverse settings. In this study, we utilized UAS to collect fine-resolution 10-band multispectral imagery of coffee agroecosystems in Puerto Rico. We created land cover maps through a pixel-based supervised classification of each farm and …
Relative Vectoring Using Dual Object Detection For Autonomous Aerial Refueling,
2024
Air Force Institute of Technology
Relative Vectoring Using Dual Object Detection For Autonomous Aerial Refueling, Derek B. Worth, Jeffrey L. Choate, James Lynch, Scott L. Nykl, Clark N. Taylor
Faculty Publications
Once realized, autonomous aerial refueling will revolutionize unmanned aviation by removing current range and endurance limitations. Previous attempts at establishing vision-based solutions have come close but rely heavily on near perfect extrinsic camera calibrations that often change midflight. In this paper, we propose dual object detection, a technique that overcomes such requirement by transforming aerial refueling imagery directly into receiver aircraft reference frame probe-to-drogue vectors regardless of camera position and orientation. These vectors are precisely what autonomous agents need to successfully maneuver the tanker and receiver aircraft in synchronous flight during refueling operations. Our method follows a common 4-stage process …
Jet-Driven Mixing Regimes Identified In The Unsteady Isothermal Filling Of Rectangular Municipal Water Storage Tanks,
2024
Missouri University of Science and Technology
Jet-Driven Mixing Regimes Identified In The Unsteady Isothermal Filling Of Rectangular Municipal Water Storage Tanks, Pramod Narayan Bangalore, K. (Kelly) O. Homan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Poor mixing of old and new water in municipal water storage vessels is a well-documented basis for potentially harmful water quality degradation in drinking water distribution systems. This numerical study investigates the effects of inflow and operational variables on mixing in the jet-driven filling process, with a particular focus on the transition from inadequate to sufficient mixing levels. An isothermal unsteady reynolds-averaged-navier-stokes volume-of-fluid (RANS-VOF) simulation is used to model the variable-volume filling process, accounting for the moving free surface following a draw-down in the stored water volume. A low diffusivity tracer is used to mark the old-water volume, and a …
Heat Treatments For Minimization Of Residual Stresses And Maximization Of Tensile Strengths Of Scalmalloy® Processed Via Directed Energy Deposition,
2024
Missouri University of Science and Technology
Heat Treatments For Minimization Of Residual Stresses And Maximization Of Tensile Strengths Of Scalmalloy® Processed Via Directed Energy Deposition, Rachel Boillat-Newport, Sriram Praneeth Isanaka, Jonathan Kelley, Frank Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Scalmalloy® is an Al-Mg-Sc-Zr-Based Alloy Specifically Developed for Additive Manufacturing (AM). This Alloy is Designed for Use with a Direct Aging Treatment, as Recommended by the Manufacturer, Rather Than with a Multistep Treatment, as Often Seen in Conventional Manufacturing. Most Work with Scalmalloy® is Conducted using Powder Bed Rather Than Powder-Fed Processes. This Investigation Seeks to Fill This Knowledge Gap and Expand Beyond Single-Step Aging to Promote an overall Balanced AM-Fabricated Component. for This Study, Directed Energy Deposition (DED)-Fabricated Scalmalloy® Components Were Subjected to Low-Temperature Treatments to Minimize Residual Stresses Inherent in the Material Due to the Layer-By-Layer Build Process. …
Optimal Abort Guidance And Experimental Verification Based On Feature Learning,
2024
Missouri University of Science and Technology
Optimal Abort Guidance And Experimental Verification Based On Feature Learning, Vinay Kenny, Sixiong You, Chaoying Pei, Godfrey Hendrix, Roha Gul, Ran Dai, Jeremy Rea
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The abort mission refers to the mission where the landing vehicle needs to terminate the landing mission when an anomaly happens and be safely guided to the desired orbit. This paper focuses on solving the time-optimal abort guidance (TOAG) problem in real-time via the feature-based learning method. First, according to the optimal control theory, the features are identified to represent the optimal solutions of TOAG using a few parameters. After that, a sufficiently large data set of time-optimal abort trajectories is generated offline by solving the TOAG problems with different initial conditions. Then, the features are extracted for all generated …
A Comparison Of Western And Eastern Soft Systems Approaches,
2024
California Polytechnic State University, San Luis Obispo
A Comparison Of Western And Eastern Soft Systems Approaches, John L. Anaya, John L. Anaya, John L. Anaya
Master's Theses
Soft System Approaches have been developed worldwide to help problem-solvers and decision-makers develop solutions to complex problems, such as aerospace systems. Soft System Approaches were designed to help lower the disorder of developing a complex system by increasing understanding of a situation. Four Soft System Approaches were investigated, two from the West and two from the East. Within the context of the paper, the West refers to thought patterns associated with thinkers and scientists in Europe and North America, and the East refers to those from and around China. The two from the West are Peter Checkland’s Soft Systems Methodology …
Discerning Satellite Subsystem Costs To Improve Cost Estimation,
2024
Air Force Institute of Technology
Discerning Satellite Subsystem Costs To Improve Cost Estimation, Ryan A. Candella
Theses and Dissertations
The race for supremacy in the space environment is accelerating, with the United States taking a significant step by establishing its dedicated military branch for space operations. Achieving dominance in this realm relies on efficiently managing costs and securing rapid funding to initiate new programs. One step towards accomplishing this goal is to comprehend the cost distribution across the primary components of a Space Vehicle Bus and to delve into lower-level Work Breakdown Structure (WBS) elements for more precise and expeditious cost estimations. To achieve this, descriptive statistics for a variety of Bus subsystem WBS elements are provided in this …
Comparative Analysis Of Satellite Battery Technologies: A Cross-Sectional And Temporal Study Within And Across Battery Types,
2024
Air Force Institute of Technology
Comparative Analysis Of Satellite Battery Technologies: A Cross-Sectional And Temporal Study Within And Across Battery Types, Andrew H. Chung
Theses and Dissertations
Trends in costs for batteries incorporated in satellite electrical power systems (EPS) have been identified by Space Systems Command (SSC) within the Unmanned Space Vehicle Cost Model (USCM) database. A subset of pre-1980s data consisting of Nickel-Cadmium battery costs was excluded from battery cost estimating relationship (CER) development as a result of this determination. This research aims to ascertain the impacts of these trends on satellite cost estimating practices by assessing developments in battery costs over time, comparing normalized Nickel-Cadmium (NiCd) / NickelHydrogen (NiH2) / Lithium-Ion (Li-Ion) battery costs, identifying differences between the NiH2 and Li-Ion modern battery types, and …
Development Of Cost Factors For Satellite Rechargeable Batteries,
2024
Air Force Institute of Technology
Development Of Cost Factors For Satellite Rechargeable Batteries, Katelyn A. Clements
Theses and Dissertations
Factors are often used by the cost estimating profession to predict costs of future projects or project components. Cost factors can be useful when little to no cost data is available from which to build an initial estimate or as an easy-to-use cross check of a primary estimate. Specific to satellites, previous studies have examined cost factors at higher Work Breakdown Structure (WBS) levels (e.g., Level 2 or Level 3), while this research analyzes cost factors developed using data specific to rechargeable batteries at USCM WBS Level 4 and its parent, the Electrical Power System (EPS) at Level 3. Within …
Computational Analysis Of Transverse Jet Interactions On A Cone In Mach 3.9 Crossflow,
2024
Air Force Institute of Technology
Computational Analysis Of Transverse Jet Interactions On A Cone In Mach 3.9 Crossflow, Tia Massa
Theses and Dissertations
The objective of this investigation was to analyze jet interactions using numerical simulations, which was compared to experimental data. A sharp cone with a 7-degree half-angle was modeled, along with the wind tunnel, using a 1:1 scale. Analysis of the data found the flow characteristics of the jet, including the bow shock and recirculation regions, were captured nicely in the CFD simulations, as well as the oblique shock off the nose of the cone. CFD simulations of the cone in a freestream environment depict shock-shock interactions not captured by experimental schlieren images. This research provides a rare glimpse into CFD …
Standardization Of Risk Classifications For Unmanned Space Vehicle Missions,
2024
Air Force Institute of Technology
Standardization Of Risk Classifications For Unmanned Space Vehicle Missions, Collin A. Gwaltney
Theses and Dissertations
This paper seeks to model risk classification levels (A-D) for 122 Space Vehicle programs. Models include multinomial logistic regression as well as random forest, a machine learning technique based on decision trees. We use independent variables (IVs) which are theoretically correlated to risk class for the regression and one random forest model. We then include all IVs and allow the random forest technique to use those which provide the most information on risk class before paring down the number of IVs to only 7. We show that the accuracy of predictions increases from 62% to 87% by using random forest …
Hardware-In-The-Loop Autonomous Trajectory Generations For On-Orbit Rendezvous And Proximity Operations,
2024
Air Force Institute of Technology
Hardware-In-The-Loop Autonomous Trajectory Generations For On-Orbit Rendezvous And Proximity Operations, Connor Slattery
Theses and Dissertations
Utilizing the C++ version of GPOPS within a robotic operating system to assess efficacy on flight-ready hardware is a vital interest of the space industry today. The findings in this paper show the ability of employing GPOPS in C++ on flight-ready hardware, leveraging optimal control as the main driver to creating a control pipleline to allow a robotic platform to generate and follow an optimized trajectory with minimal user input.
