Engineering Commons^™

Filtered-Dynamic-Inversion Control For Fixed-Wing Unmanned Aerial Systems, Jon Mullen

Theses and Dissertations--Mechanical and Aerospace Engineering

Instrumented umanned aerial vehicles represent a new way of measuring turbulence in the atmospheric boundary layer. However, autonomous measurements require control methods with disturbance-rejection and altitude command-following capabilities. Filtered dynamic inversion is a control method with desirable disturbance-rejection and command-following properties, and this controller requires limited model information. We implement filtered dynamic inversion as the pitch controller in an altitude-hold autopilot. We design and numerically simulate the continuous-time and discrete-time filtered-dynamic-inversion controllers with anti-windup on a nonlinear aircraft model. Finally, we present results from a flight experiment comparing the filtered-dynamic-inversion controller to a classical proportional-integral controller. The experimental results show …

Multidimensional Modeling Of Pyrolysis Gas Transport Inside Orthotropic Charring Ablators, Haoyue Weng

Theses and Dissertations--Mechanical and Aerospace Engineering

During hypersonic atmospheric entry, spacecraft are exposed to enormous aerodynamic heat. To prevent the payload from overheating, charring ablative materials are favored to be applied as the heat shield at the exposing surface of the vehicle. Accurate modeling not only prevents mission failures, but also helps reduce cost. Existing models were mostly limited to one-dimensional and discrepancies were shown against measured experiments and flight-data. To help improve the models and analyze the charring ablation problems, a multidimensional material response module is developed, based on a finite volume method framework. The developed computer program is verified through a series of test-cases, …

Load Transfer In An Isolated Particle Embedded Within An Epoxy Matrix, Erik Durnberg

Electronic Theses and Dissertations

Particulate composites are widely used in many aerospace applications such as protective coatings, adhesives, or structural members of a body and their mechanical properties and behavior have gained increasing significance. The addition of modifiers such as alumina generally leads to improved mechanical properties. This addition also enables the non-invasive study of the load transfer between the particle and the matrix. Understanding the load transfer between the particulate and the matrix material is the first step to understanding the behavior and mechanical properties of the composite as a whole. In this work, samples with an isolated alumina particle embedded in an …

Ignition Studies Of Diisopropyl Ketone, A Second-Generation Biofuel, Owen Pryor

HIM 1990-2015

This thesis focuses on ignition of diisopropyl ketone (DIPK), a new biofuel candidate that is produced by endophytic conversion. The ignition delay times behind reflected shockwaves were modeled in a high-pressure shock tube. The ignition delay times were compared to other biofuels and gasoline surrogates. Parametric studies of the ignition delay experiments were performed between 1-10 atm and 900 -1200K. An OH optical sensor was developed in conjunction for the ignition delay experiments. The OH optical sensor uses a microwave discharge lamp to generate light at 308 nm that will then be shined through the combustion reaction. Using Beer-Lambert law …

Nondestructive Analysis Of Advanced Aerospace Materials Via Spectroscopy And Synchrotron Radiation, Albert Manero

Electronic Theses and Dissertations

Advanced aerospace materials require extensive testing and characterization to anticipate and ensure their integrity under hostile environments. Characterization methods utilizing synchrotron X-Ray diffraction and spectroscopy can decrease the time required to determine an emerging material's readiness for application through intrinsic information on the material response and failure mechanisms. In this study, thermal barrier coating samples applicable to turbine blades of jet engines were studied using Raman and Photoluminescence spectroscopy as well as Synchrotron X-ray diffraction while Kevlar based fiber composites applicable to ballistic resistant armor were studied using Raman spectroscopy to investigate the mechanical state and corresponding damage and failure …

Keeping The Skies Safe, Massood Towhidnejad, Andrew J. Kornecki

Department of Electrical Engineering and Computer Science - Daytona Beach

Professors Massood Towhidnejad and Andrew Kornecki shine a light on how their lab is helping government and the aviation industry to enhance the safety and security of software-intensive systems.

Space Tourism: Hurdles And Hopes, Robert A. Goehlich

Publications

According to the Space Policy Institute (2002, Bib. section), “Space tourism is the term broadly applied to the concept of paying customers traveling beyond Earth’s atmosphere.” Operating reusable launch vehicles (RLVs) might be a first step toward achieving mass space tourism. Thus, the aim of this article is to investigate the potential hurdles and other aspects of importance that must be overcome in order to use RLVs for space tourism flights. The primary ones are social issues (e.g., “Is space tourism ethically acceptable?”), institutional issues (e.g., “Is environmental pollution caused by space tourism more harmful than other emission sources?”), and …

Robust And Adaptive Nonlinear Control Of Limit Cycle Oscillations In Uavs Using Synthetic Jet Actuators, Natalie Ramos Pedroza

Doctoral Dissertations and Master's Theses

Limit cycle oscillations (LCO), also known as utter, cause significant challenges in fight control of unmanned aerial vehicles (UAVs), and could potentially lead to structural damage and catastrophic failures. LCO can be described as vibrational motions in the pitching and plunging displacements of an aircraft wing. Even in low Reynolds number (low-Re) fight regimes, LCO can exceed the limiting boundary for safe UAV fight. Further, as practical considerations motivate the design of smaller, lighter weight UAVs, there is a growing need for UAV systems that do not require heavy mechanical actuators (e.g., ailerons). To address this, the use of synthetic …

Development And Operation Of The Pocketqube T-Logoqube, Kevin Zack

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Kevin Zack titled "Development and Operation of the PocketQube T-LogoQube" from April 22, 2014.

Identifiability Of Additive Actuator And Sensor Faults By State Augmentation, Suresh M. Joshi, Oscar R. Gonzalez, Jason M. Upchurch

Electrical & Computer Engineering Faculty Publications

A class of FDI (fault detection and identification) methods for bias-type actuator and sensor faults was explored from the point of view of fault identifiability. The methods use banks of Kalman-Bucy filters (KBFs) to detect faults, determine the fault pattern, and estimate the fault values. A complete characterization of conditions for identifiability of bias-type actuator faults, sensor faults, and simultaneous actuator and sensor faults was presented. It was shown that FDI of simultaneous actuator and sensor faults is not possible using these methods when all sensors have unknown biases. The fault identifiability conditions were demonstrated via numerical examples. The analytical …

Intelligent Sensing Based On Low Cost Unmanned Aerial Vehicles (Uav) For Bridge Condition Assessment, Theodore Teates, Austin Boyd, Chung-Hao Chen

Electrical & Computer Engineering Faculty Publications

The eventual completion of this project envisions the use of an Unmanned Aerial Vehicle (UAV) to inspect bridge infrastructure. This project may also be expanded to encompass general object detection and inspection in order to unburden this technology so that it may reach its fullest potential. The project requires research and development in three distinct areas of image processing, control structures, and integration of systems. Initial undergraduate research sets the base knowledge for the overall project, explores the areas of concentration that are desired to expand upon in the future project, and provides a base UAV model that new researchers …

Improving Plasma Actuator Performance At Low Pressure, And An Analysis Of The Pointing Capabilities Of Cubesats Using Plasmonic Force Propulsion (Pfp) Thrusters, Paul Daniel Friz

Masters Theses

"This thesis details the work done on two unrelated projects, plasma actuators, an aerodynamic flow control device, and Plasmonic Force Propulsion (PFP) thrusters, a space propulsion system for small satellites.

The first half of the thesis is a paper published in the International Journal of Flow Control on plasma actuators. In this paper the thrust and power consumption of plasma actuators with varying geometries was studied at varying pressure. It was found that actuators with longer buried electrodes produce the most thrust over all and that they substantially improved thrust at low pressure. In particular actuators with 75 mm buried …

Approximate Dynamic Programming, Local Or Global Optimal Solution?, Ali Heydari, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The problem of global optimality analysis of approximate dynamic programming-based solutions is investigated in this study. Sufficient conditions for global optimality are obtained without requiring the state penalizing terms in the cost function or the functions representing the dynamics to be convex functions. Afterwards, the theoretical results are confirmed through a qualitative analysis of an example problem. © 2014 American Automatic Control Council.

Cognitive Challenges To Resilience Dynamics In Managing Large- Scale Event Response, Barrett S. Caldwell

School of Industrial Engineering Faculty Publications

In early 2014, a number of large-scale adverse weather events in the United States (and elsewhere) have renewed discussions of event response and resilience. Unlike events caused by human error or malicious intent, adverse natural events can be seen as uncontrolled and unpreventable; the measure of response success is the mitigation of adverse and disastrous effects. However, significant cognitive limitations interfere with human decision makers’ ability to effectively estimate likelihood, magnitude, and effective response of large-scale events in the face of multiple forms of uncertainty and system dependencies. Some authors highlight stability and maintenance of original design capability as …

Role Of Surface Chemistry In Nanoscale Electrokinetic Transport, Secuk Atalay

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation work presents the efforts to study the electrofluidics phenomena, with a focus on surface charge properties in nanoscale systems with the potential applications in imaging, energy conversion, ultrafiltration, DNA analysis/sequencing, DNA and protein transport, drug delivery, biological/chemical agent detection and micro/nano chip sensors.

Since the ion or molecular or particle transport and also liquid confinement in nano-structures are strongly dominated by the surface charge properties, in regards of the fundamental understanding of electrofluidics at nanoscale, we have used surface charge chemistry properties based on 2-pK charging mechanism. Using this mechanism, we theoretically and analytically showed the surface charge …

Autonomous Capabilities For Small Unmanned Aerial Systems Conducting Radiological Response: Findings From A High-Fidelity Discovery Experiment, Brittany Duncan, Robin Murphy

School of Computing: Faculty Publications

This article presents a preliminary work domain theory and identifies autonomous vehicle, navigational, and mission capabilities and challenges for small unmanned aerial systems (SUASs) responding to a radiological disaster. Radiological events are representative of applications that involve flying at low altitudes and close proximities to structures. To more formally understand the guidance and control demands, the environment in which the SUAS has to function, and the expected missions, tasks, and strategies to respond to an incident, a discovery experiment was performed in 2013. The experiment placed a radiological source emitting at 10 times background radiation in the simulated collapse of …

Daily Area Of Snow Melt Onset On Arctic Sea Ice From Passive Microwave Satellite Observations 1979–2012, Angela C. Bliss, Mark R. Anderson

Department of Earth and Atmospheric Sciences: Faculty Publications

Variability in snow melt onset (MO) on Arctic sea ice since 1979 is examined by determining the area of sea ice experiencing the onset of melting during the melt season on a daily basis. The daily MO area of the snow and ice surface is determined from passive microwave satellite-derived MO dates for the Arctic Ocean and sub-regions. Annual accumulations of MO area are determined by summing the time series of daily MO area through the melt season. Daily areas and annual accumulations of MO area highlight inter-annual and regional variability in the timing of MO area, which is sensitive …

A Decision Making Framework With Modflow-Fmp2 Via Optimization: Determining Trade-Offs In Crop Selection, K R. Fowler, E W. Jenkins, C Ostrove, J C. Chispell, M W. Farthing, M Parno

United States Army Corps of Engineers, Omaha District

Farmers in regions experiencing water stress or drought conditions can struggle to balance their crop portfolios. Periods of low precipitation often lead to increased, unsustainable reliance on groundwatersupplied irrigation. As a result, regional water management agencies place limits on the amount of water which can be obtained from groundwater, requiring farmers to reduce acreage for more water-intensive crops or remove them from the portfolio entirely. Real-time decisions must be made by the farmer to ensure viability of their farming operation and reduce the impacts associated with limited water resources. Evolutionary algorithms, coupled with accurate, flexible, realistic simulation tools, are ideal …

A Low Cost Implementation Of Autonomous Takeoff And Landing For A Fixed Wing Uav, Thomas Carnes

Theses and Dissertations

The take-off and landing of an Unmanned Aerial Vehicle (UAV) is often the most critical and accident prone portion of its mission. This potential hazard coupled with the time and resources necessary to train a remote UAV pilot makes it desirable to have autonomous take-off and landing capabilities for UAVs. However, a robust, reliable, and accurate autonomous takeoff and landing capability for fixed-wing aircraft is not an available feature in many low-cost UAV flight control systems. This thesis describes the design of an autonomous take-off and landing algorithm implemented on an existing low-cost flight control system for a small fixed …

Control Design And Performance Analysis For Autonomous Formation Flight Experiments, Caleb M. Rice

Graduate Theses, Dissertations, and Problem Reports (ETD)

Autonomous Formation Flight is a key approach for reducing greenhouse gas emissions and managing traffic in future high density airspace. Unmanned Aerial Vehicles (UAV’s) have made it possible for the physical demonstration and validation of autonomous formation flight concepts inexpensively and eliminates the flight risk to human pilots. This thesis discusses the design, implementation, and flight testing of three different formation flight control methods, Proportional Integral and Derivative (PID); Fuzzy Logic (FL); and NonLinear Dynamic Inversion (NLDI), and their respective performance behavior. Experimental results show achievable autonomous formation flight and performance quality with a pair of low-cost unmanned research fixed …

Fault-Tolerant Trajectory Tracking Of Unmanned Aerial Vehicles Using Immunity-Based Model Reference Adaptive Control, Brenton K. Wilburn

Graduate Theses, Dissertations, and Problem Reports (ETD)

This dissertation presents the design, development, and simulation testing of an adaptive trajectory tracking algorithm capable of compensating for various aircraft subsystem failures and upset conditions. A comprehensive adaptive control framework, here within referred to as the immune model reference adaptive control (IMRAC) algorithm, is developed by synergistically merging core concepts from the biologically- inspired artificial immune system (AIS) paradigm with more traditional optimal and adaptive control techniques. In particular, a model reference adaptive control (MRAC) algorithm is enhanced with the detection and learning capabilities of a novel, artificial neural network augmented AIS scheme. With the given modifications, the MRAC …

Energy Deposition Into Heavy Gas Plasma Via Pulsed Inductive Theta-Pinch, Ryan Alan Pahl

Doctoral Dissertations

"The objective of this research is to study the formation processes of a pulsed inductive plasma using heavy gases, specifically the coupling of stored capacitive energy into plasma via formation in a theta pinch coil. To aid in this research, the Missouri Plasmoid Experiment Mk. I (and later Mk. II) was created.

In the first paper, the construction of differential magnetic field probes are discussed. The effects of calibration setup on B-dot probes is studied using a Helmholtz coil driven by a vector network analyzer and a pulsed-power system. Calibration in a pulsed-power environment yielded calibration factors at least 9.7% …

Experimental Studies Of Lox/Ch4 Uni-Element Shear Coaxial Injector Geometry, Vanessa Dorado-Martinez

Open Access Theses & Dissertations

The Center for Space Exploration Technology Research (cSETR) has developed a set of shear coaxial injectors as part of a system-level approach to study LOX/CH4 combustion. This Thesis describes the experimental studies involved in the characterization of the effects produced by two design injection face plate variables: post thickness and recession length. A testing program was developed to study the injectors' atomization process using LN2 as a substitute for LOX in cold flow and the flame anchoring mechanisms in hot firings. The cold flow testing stage was conducted to obtain liquid core measurements and compare its behavior between the different …

Characterizing Cryogenic Propellant Flow Behavior Through A Cavitating Venturi In Comparison To Alternative Flow Control Mechanisms, Marjorie Adele Ingle

Open Access Theses & Dissertations

The work detailed is an investigation of the use of a cavitating venturi as both a flow control and metering device. This was achieved through the combination of actual experimentation and numerical modeling of the fluid behavior of both liquid water and liquid methane as it passes through the test article designed, developed, and validated here within this study. The discharge coefficient of the cavitating venturi was determined through weigh flow calibration testing to determine an average mass flow rate. Turbine flow meter flow rate readings were used as a point of comparison and the discharge coefficient was computed. The …

Decision Making Model For Foreign Object Debris/Damage (Fod) Elimination In Aeronautics Using Quantitative Modeling Approach, Jose Jaime Lafon

Open Access Theses & Dissertations

(FOD) Foreign Object Debris/Damage has been a costly issue for the commercial and military aircraft manufacturers at their production lines every day. FOD can put pilots, passengers and other crews' lives into high-risk. FOD refers to any type of foreign object, particle, debris or agent in the manufacturing environment, which could contaminate/damage the product or otherwise undermine quality standards. Nowadays, FOD is currently addressed with prevention programs, elimination techniques, and designation of FOD areas, controlled access to FOD areas, restrictions of personal items entering designated areas, tool accountability, etc. All of the efforts mentioned before, have not shown a significant …

Performance Evaluation Of A Lox-Lch4 Reaction Control System Thruster, Jose Luis Mena

Open Access Theses & Dissertations

The following work outlines the assessment and characterization of a 2 to 8 lbf LOX - LCH4 reaction control thruster. The evaluation includes both experimental tests and preliminary computational analysis. Testing was conducted at O/F values ranging from 1.0 to 3.0; however, future testing will evaluate the thruster at higher and intermediate mixture ratios. The test setup includes three main systems: cryogenic propellant delivery system, thrust measurement capability, and automation and controls system. Propellant flow control is achieved through the use of in-house designed cavitating venturis. Autonomous system control is accomplished via a LabVIEW program interface and DAQ system. This …

An Experimental Investigation Of The Cooling Channel Geometry Effects On The Internal Forced Convection Of Liquid Methane, Adrian Trejo

Open Access Theses & Dissertations

Rocket engine fuel alternatives have been an area of discussion for use in high performance engines and deep spaceflight missions. In particular, LCH4 has showed promise as an alternative option in regeneratively cooled rocket engines due to its non-toxic nature, similar storage temperatures to liquid oxygen, and its potential as an in situ resource. However, data pertaining to the heat transfer characteristics of LCH4 is limited. For this reason, a High Heat Transfer Test Facility (HHTTF) at the University of Texas at El Paso's (UTEP) Center for Space Exploration Technology and Research has been developed for the purpose of flowing …

A Wedge Impact Theory Used To Predict Bow Slamming Forces, Ashok Benjamin Basil Attumaly

LSU New Orleans Theses and Dissertations

The pressures and impact forces acting on a hull while experiencing bow wave slamming is analyzed using Vorus' Impact Theory. The theory extends the hydrodynamic analysis of planing hulls from simple wedges to irregular shapes using a Boundary Element Method. A Fortran-based code developed by the Author is used to analyze hullforms. Linear strip theory is used to extend the analysis over a three dimensional hull. Post-processing of output data gives hull pressure distributions at different time steps and is visually presentable.

Impact pressure, Impact force, Planing, Wave slamming, Bow impact, Vorus' theory, Boundary Element Method, Linear strip theory

Experimental Investigation Of Mist Film Cooling And Feasibility Study Of Mist Transport In Gas Turbines, Reda M. Ragab

LSU New Orleans Theses and Dissertations

In the modern advanced gas turbines, the turbine inlet temperature may exceed 1500°C as a requirement to increase power output and thermal efficiency. Therefore, it is imperative that the blades and vanes are cooled so they can withstand these extreme temperatures. Film cooling is a cooling technique widely used in high-performance gas turbines. However, the film cooling effectiveness has almost reached plateau, resulting in a bottleneck for continuous improvement of gas turbines' efficiency.

In this study, an innovative cooling scheme, mist film cooling is investigated through experiments. A small amount of tiny water droplets with an average diameter about 10-15 …

Buckling, Postbuckling And Imperfection Sensitivity Analysis Of Different Type Of Cylindrical Shells By Hui's Postbuckling Method, Hailan Xu

LSU New Orleans Theses and Dissertations

Hui and Chen (1986) were the first to show that the well-known Koiter’s General Theory of Elastic Stability of 1945 can be significantly improved by evaluating the postbuckling b coefficient at the actual applied load, rather than at the classical buckling load. Such improvement method was demonstrated to be (1) very simple to apply with no tedious algebra, (2) significant reduction in imperfection sensitivity and (3) although it is still asymptotically valid, there exists a significant extension of the range of validity involving larger imperfection amplitudes. Strictly speaking, Koiter’s theory of 1945 is valid only for vanishingly small imperfection amplitudes. …