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Comparison Of Partially Decoupled And Combined Methods Of Path Planning And Task Allocation, Jennifer Beth Hazelton
Comparison Of Partially Decoupled And Combined Methods Of Path Planning And Task Allocation, Jennifer Beth Hazelton
Graduate Theses, Dissertations, and Problem Reports
Developing autonomous unmanned aerial vehicles (UAVs) reduces the risks to which soldiers are subjected by enabling the UAVs to make efficient decisions, regardless of the situation. This requires each group of UAVs to be proficient in planning their own paths and assigning tasks in a way that minimizes the total cost of the mission. Two methods are presented for doing this, the partially decoupled approach and the combined approach. After comparing two methods, the partially decoupled approach costs an average of 3.0 meters less than the combined approach, while taking an average of 0.327 seconds longer to complete. This indicates …
Decentralized Control For Uav Path Planning And Task Allocation, Matthew C. Lechliter
Decentralized Control For Uav Path Planning And Task Allocation, Matthew C. Lechliter
Graduate Theses, Dissertations, and Problem Reports
The effort of this research is to move toward enabling Unmanned Air Vehicles to fly in autonomous formations with intelligent mission planning capabilities. In particular, UAVs will be able to autonomously perform path planning and task allocation. During missions, the UAVs must be able to avoid threats and no-fly zones while still reaching their target optimally in time.;A path planning and task allocation approach was first developed that treats the problem as a Multi-dimensional, Multiple-Choice Knapsack Problem. Paths are selected and task assigned while minimizing the UAV team's overall mission cost. Next, a SIMULINK-based centralized simulation environment was created. This …
Comparison Of Path-Planning And Search Methods For Cooperating Unmanned Aerial Vehicles, Zachary Wilson Spritzer
Comparison Of Path-Planning And Search Methods For Cooperating Unmanned Aerial Vehicles, Zachary Wilson Spritzer
Graduate Theses, Dissertations, and Problem Reports
The main goal of this research effort is develop a simulation environment for cooperating UAVs within MATLAB's SIMULINK. This is the first step in a process that will eventually lead to the implementation of model UAVs on a model battlefield. The interest in cooperation of UAVs over the past decade has grown significantly. This is due to several reasons including lower operational cost, lower risk for humans, and greater maneuverability.;This research explores two scenarios. The first is a scenario in which all of the characteristics of a battlefield are known prior to the UAVs being launched. Three prevalent path-planning methods …
Flow Characterization Of The Ul Smoke Box And Spot-Type Smoke Detectors, Christopher P. Menchini
Flow Characterization Of The Ul Smoke Box And Spot-Type Smoke Detectors, Christopher P. Menchini
Graduate Theses, Dissertations, and Problem Reports
The scope of this research involves the first known effort at designing a highly detailed computational fluid dynamics (CFD) model to characterize the flow fields with the UL Smoke Box and a spot type smoke detector within the test section of the smoke box. The proposed CFD model, designed to reflect the same measured conditions in the UL Smoke Box, was developed and validated through experimental velocity data using laser Doppler and hot-wire anemometry. With excellent qualitative comparisons between experimental and computational results, flow characterization using the laminar flow model available in the commercial software package FluentRTM was sufficiently achieved. …
Circulation Control For Download Wake Reduction On A Scaled V-22 Model, Chad Alan Riba
Circulation Control For Download Wake Reduction On A Scaled V-22 Model, Chad Alan Riba
Graduate Theses, Dissertations, and Problem Reports
West Virginia University has developed a circulation controlled model of the V-22 wing to reduce the size of the download in the wake region brought upon by the airflow from the proprotors. The techniques being used in this experiment are the implementation of blowing slots across the leading edge and trailing edge, activation of one or both of the blowing devices, and adjustment of slot velocity. The results of the study show a decrease in the download force through the incorporation of the Coanda Effect around the leading and trailing edges. The induction of this phenomenon will move the separation …
Flight Testing Of A Remotely Piloted Vehicle For Aircraft Parameter Estimation Purposes, Brad A. Seanor
Flight Testing Of A Remotely Piloted Vehicle For Aircraft Parameter Estimation Purposes, Brad A. Seanor
Graduate Theses, Dissertations, and Problem Reports
The contribution of this research effort was to show that a reliable RPV could be built, tested, and successfully used for flight testing and parameter estimation purposes, in an academic setting. This was a fundamental step towards the creation of an automated Unmanned Aerial Vehicle (UAV). This research project was divided into four phases. Phase one involved the construction, development, and initial flight of a Remotely Piloted Vehicle (RPV), the West Virginia University (WVU) Boeing 777 (B777) aircraft. This phase included the creation of an onboard instrumentation system to provide aircraft flight data. The objective of the second phase was …
Aging Model For Commercial Polymers, Kevin J. Ford
Aging Model For Commercial Polymers, Kevin J. Ford
Graduate Theses, Dissertations, and Problem Reports
Physical aging of polyvinyl chloride, high-density polyethylene, and polyester reinforced with polyester fibers specimens have been investigated. These materials are commercially available and are currently used in trenchless relining of sewer pipes. The analysis uses the effective-time theory and time-temperature superposition (TTSP) methods proposed by Struik, as well as variations of these methods, as proposed by Chai and McCrum, Guerdoux et al. and others. The creep data generated by this study show that the time-dependent creep properties of these materials can be modeled within experimental error with slight changes to the above methods. To predict the creep behavior of full-scale …
Experimental Study Of Thermosiphon Performance, Sumeeth S. Sivanagere
Experimental Study Of Thermosiphon Performance, Sumeeth S. Sivanagere
Graduate Theses, Dissertations, and Problem Reports
A model single phase loop thermosiphon was designed and built such that velocity profiles and heat transfer rates could be studied by obtaining temperature data, along with a detailed set of non-intrusive Laser Doppler Velocimetry measurements. The quantities measured were the instantaneous velocity profiles for the water flow. These velocities were then reduced into sets of mean and root mean square velocities, for different angles of tilt of the experimental setup. Nominal heating and cooling rates were held constant.;The single phase thermosiphon consisted of an aluminum flow loop, fitted with a test section made of Plexiglas, that was rectangular in …
Dynamic Model Of The Interface Reactions In An Aircraft Bomb Rack Due To An External Store, Tim C. Schoppert
Dynamic Model Of The Interface Reactions In An Aircraft Bomb Rack Due To An External Store, Tim C. Schoppert
Graduate Theses, Dissertations, and Problem Reports
In today's downsizing environment, more demands than ever are being placed on aircraft flight test programs. To compensate for shrinking budgets and increased requirements, new and more versatile test techniques and data processing systems must be developed. Standard flight test procedures must be reexamined and optimized to maximize the availability of the test asset while processing the collected data more quickly and at a lower cost.;This research demonstrated the ability to predict the reaction loads transmitted to an aircraft bomb rack due to the inertial forces acting on an external store. These load calculations typically require lengthy test programs with …
Lda And Cta In-Cylinder Measurements Of Intake-Generated Turbulence For Steady Flow Around A Centrally Located Valve, Gearle Ray Bailey Jr.
Lda And Cta In-Cylinder Measurements Of Intake-Generated Turbulence For Steady Flow Around A Centrally Located Valve, Gearle Ray Bailey Jr.
Graduate Theses, Dissertations, and Problem Reports
The purpose of this study was to measure the axial and swirl velocities for steady flow in a cylinder past an intake valve, in order to study the effects of swirl and valve lift on turbulence generation. A simple geometry was used for an initial look at the flow past a valve.;A cylinder with a centrally located valve was used as the test bed. The valve was tested at lifts of 4 and 9 mm Two intake geometries were tested: a straight intake port and a swirl intake port. A single sensor Constant Temperature Anemometry (CTA) and a one-component Laser …
Improved Velocity Data In Circular Jets Using An Avalanche Photodiode-Based 2-Component Point Doppler Velocimeter, Thomas Trent Scarberry
Improved Velocity Data In Circular Jets Using An Avalanche Photodiode-Based 2-Component Point Doppler Velocimeter, Thomas Trent Scarberry
Graduate Theses, Dissertations, and Problem Reports
An existing Point Doppler Velocimeter (pDv) has been modified in an effort to improve the RMS velocity results. Improvements have been made by reducing the probe volume size by focusing the incident laser beam, thereby reducing the effects of spatial averaging on the mean and RMS velocity measurements.;In particular, the PIN photodetectors used previously, were tested using the reduced probe volume, and were then replaced by high-gain, high signal-to-noise ratio large area avalanche photodetectors (APD's).;Comparisons have been made between the data acquired and hot wire data obtained on the same jet flow, as well as data obtained in previous pDv …
Evaluation Of Exhaust Flowrate Measurement Techniques For A Mobile Emissions Monitoring System, Eric Todd Meyer
Evaluation Of Exhaust Flowrate Measurement Techniques For A Mobile Emissions Monitoring System, Eric Todd Meyer
Graduate Theses, Dissertations, and Problem Reports
West Virginia University designed and developed Mobile Emissions Monitoring System (MEMS) for the six settling Heavy-Duty Diesel Engine (S-HDDE) manufacturers. The MEMS measures emissions concentrations while operating in a real world environment. The best method for measuring the emissions concentrations was found to be through raw exhaust sampling. In order to properly calculate the emissions concentrations the total exhaust flowrate through the engine must be determined. The devices evaluated were an Annubar, an Accutube, a hot film anemometer, a Pitot static tube, a venturi, and a vortex shedder.;The evaluation of the devices was broken down into two parts, the first …
Formal Specification Of Requirements For Analytical Redundancy-Based Fault -Tolerant Flight Control Systems, Diego Del Gobbo
Formal Specification Of Requirements For Analytical Redundancy-Based Fault -Tolerant Flight Control Systems, Diego Del Gobbo
Graduate Theses, Dissertations, and Problem Reports
Flight control systems are undergoing a rapid process of automation. The use of Fly-By-Wire digital flight control systems in commercial aviation (Airbus 320 and Boeing FBW-B777) is a clear sign of this trend. The increased automation goes in parallel with an increased complexity of flight control systems with obvious consequences on reliability and safety. Flight control systems must meet strict fault-tolerance requirements. The standard solution to achieving fault tolerance capability relies on multi-string architectures. On the other hand, multi-string architectures further increase the complexity of the system inducing a reduction of overall reliability.;In the past two decades a variety of …
Assessment Of A Space Shuttle Trajectory Evaluation System (Dolilu Ii), Diwakar Chakravarthy
Assessment Of A Space Shuttle Trajectory Evaluation System (Dolilu Ii), Diwakar Chakravarthy
Graduate Theses, Dissertations, and Problem Reports
DOLILU II is a ground control system that generates space shuttle's launch trajectories, first stage guidance commands and verifies whether the generated trajectories are safe for the flight. It is a safety critical system and a high degree of confidence in its safety and reliability must be gained through assessment. We addressed three issues related to its safety and reliability assessment. We developed a reliability assessment framework for DOLILU II system. We proposed techniques to speed up test case execution and designed methodologies for the generation of input conditions needed to test the system.;We used a Bayesian statistical framework for …
Emissions And Operational Aspects Of Methanol As An Alternative Fuel In A Stationary Gas Turbine, Richard William Guiler
Emissions And Operational Aspects Of Methanol As An Alternative Fuel In A Stationary Gas Turbine, Richard William Guiler
Graduate Theses, Dissertations, and Problem Reports
During this research techniques have been developed to measure the lubricating properties of methanol and various additives. Suitable lubricant additives were found to improve methanol's lubricity to equal that of aviation kerosene, with as little as 1% additive. The lower heating value of methanol required modifications to the WVU gas turbine's fuel system and atomizer, to provide higher flow rate of fuel then required with aviation kerosene. The gas turbine was modified and operated on methanol for an extended period, without failure. Exhaust gas emissions were tested for carbon monoxide (CO), carbon dioxide (CO2), oxides of nitrogen (NOx), total hydrocarbons …
Inventory And Prediction Of Heavy-Duty Diesel Vehicle Emissions, Justin Michael Kern
Inventory And Prediction Of Heavy-Duty Diesel Vehicle Emissions, Justin Michael Kern
Graduate Theses, Dissertations, and Problem Reports
A vehicle emissions inventory is an account of emissions produced by all vehicles in an area. Many different factors can affect the emissions and the measurement of the emissions that are used to create an emissions inventory. These factors for heavy-duty diesel vehicles have been addressed and their relative affect on emissions was evaluated from test data and analytical analyses. These elements can affect the emissions by a factor of 15 depending on testing conditions.;One purpose that an emissions database serves is to provide a source for predicting future emissions for a specific vehicle or many vehicles in a general …
Alloying Effects On High-Temperature Deformation Behavior Of Nickel Aluminide Intermetallics, Robert Adrian Coulter Ii
Alloying Effects On High-Temperature Deformation Behavior Of Nickel Aluminide Intermetallics, Robert Adrian Coulter Ii
Graduate Theses, Dissertations, and Problem Reports
The objective of this research is to examine the possibility of using nickel aluminide for high temperature structural applications. NiAl is a desirable candidate based on its low density, high thermal conductivity, high melting temperature, and its proven oxidation resistance. Currently, limited ductility at lower temperatures and low creep resistance at high temperatures limit the capabilities of NiAl.;For this research four different alloys were investigated to determine the effects of alloy strengthening. The three elements are next to one another on the periodic table, which will provide the electron number effect (Mo vs. Nb) and the atomic size effect (Cr …
Refined Turbulence Models For Simulation Of Ic -Engine Cylinder Flows, Ibrahim Yavuz
Refined Turbulence Models For Simulation Of Ic -Engine Cylinder Flows, Ibrahim Yavuz
Graduate Theses, Dissertations, and Problem Reports
Turbulence and turbulent mixing are two of the most important factors that influence the efficiency and emissions level in internal combustion (IC) engines, particularly for diesel engines. This study has been performed with the premise to accurately predict in-cylinder turbulence by employing the large eddy simulation (LES) technique. In order to assess the turbulence scales involved correctly, a review of measured and computed scales relevant to IC engines is conducted. An assessment of these is made in comparison with the self-imposed scales of the engine itself. This assessment focuses on the influence of combustion, compression ratio, initial conditions and numerical …
Point Doppler Velocimetry Measurements In Circular Jets, Patrick Michael Collins
Point Doppler Velocimetry Measurements In Circular Jets, Patrick Michael Collins
Graduate Theses, Dissertations, and Problem Reports
Improvements have been made to an existing 2-component Point Doppler Velocimetry (PDV) system to improve instrument accuracy and repeatability and to reduce mean velocity offset. Most importantly, the original iodine cells have been replaced by vapor-limited iodine cells that are not influenced by room temperature variations. PDV is a non-intrusive laser based flow measurement technique with capabilities that are similar to hot wire anemometry, but without inserting a probe into the flow. The insertion of a probe into a flow can affect the flow, resulting in inaccurate measurements.;PDV measurements for 1 inch diameter standard, swirling, and annular jets have been …
Compressive Strength Prediction For Composite Unmanned Aerial Vehicles, Edward Albert Wen
Compressive Strength Prediction For Composite Unmanned Aerial Vehicles, Edward Albert Wen
Graduate Theses, Dissertations, and Problem Reports
A rational methodology is presented to predict the compressive strength of carbon/epoxy compression specimens and prototype production parts using the model presented by Barbero in the Journal of Composite Materials, Vol. 32, No.5/1998. The experimental technique is an adaptation of the optical method first proposed by Yurgartis (1987) and can be directly applied to actual development, quality control or failure investigation programs. There is very good agreement between actual and predicted compressive strength at -125F and room temperature. At 180F, the predicted strength is conservative. Aurora Flight Sciences provided the prototype production parts and partial funding under the "Material Characterization …
Mission Planning And Remote Operated Vehicle Simulation In A Virtual Reality Interface, Christopher Samuel Allport
Mission Planning And Remote Operated Vehicle Simulation In A Virtual Reality Interface, Christopher Samuel Allport
Graduate Theses, Dissertations, and Problem Reports
Virtual reality simulations are finding applications in a wide range of disciplines such as surgical simulation, electronics training, and crime scene investigation. During the Mars Pathfinder Mission, in summer 1997, NASA scientists unveiled a new application of virtual reality for the visualization of a planetary surface. The success of this application led to a more concentrated effort for using virtual reality visualization tools during future missions. The thrust of this effort was to develop a new interface which would allow scientists to interactively plan experiments to be performed by the mission robots. This thesis covers two of the primary aspects …
Development And Accuracy Determination Of A Two-Component Doppler Global Velocimeter (Dgv), Stephen M. Naylor
Development And Accuracy Determination Of A Two-Component Doppler Global Velocimeter (Dgv), Stephen M. Naylor
Graduate Theses, Dissertations, and Problem Reports
A two-component Doppler Global Velocimeter (DGV) system was constructed and tested to research problems associated with the accuracy of this unique system. The uniqueness of the system lies in its ability to simultaneously and non-intrusively measure velocities in a laser illuminated plane. A key component of the system is a frequency discriminating optical filter containing iodine vapor which allows direct measurement of the Doppler frequency shift caused by particle motion. Corrections for optical distortions and non-uniform intensities as well as the conversions from intensity data to velocity data are performed by an extensive image processing algorithm. Measurements were made of …