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Articles 31 - 46 of 46
Full-Text Articles in Engineering
Simulation Of The Dynamically Coupled Kc-135 Tanker And Refueling Boom, Jeremy J. Smith
Simulation Of The Dynamically Coupled Kc-135 Tanker And Refueling Boom, Jeremy J. Smith
Theses and Dissertations
Future Air Force requirements for the use of unmanned aircraft will require Automated Aerial Refueling (AAR). Current AAR research requires a precision model to simulate the refueling process of a KC-135 tanker and a UAV. There are existing high fidelity models of the tanker aircraft, refueling boom and proposed receiver aircraft. However, none of the models are coupled. Since boom orientation and motion is known to change the trim of the tanker aircraft, which in turn influences all other aspects of the refueling process, a new model is needed. The new model was created by integrating an existing KC-135 tanker …
Scaling Flight Tests Of Unmanned Air Vehicles, Jeevani I. Abeygoonewardene
Scaling Flight Tests Of Unmanned Air Vehicles, Jeevani I. Abeygoonewardene
Theses and Dissertations
Increasing technological advances and research interest in unmanned air vehicles (UAVs), have led to the need for having safe, inexpensive and effective means of experimenting with their fight performance and surveillance capabilities. Work has previously been done in areas of controlling, analyzing, and predicting cooperative and autonomous operations of UAVs and other vehicles. In addition, there are well established guidelines for scaling experiments in fluid mechanics, where geometric, kinematic and dynamic similarity is obtained by formulating problems in terms of non dimensional variables using dimensional analysis. However, little or no work has been done in developing experiments or guidelines for …
Experimental Analysis Of Propeller Interactions With A Flexible Wing Micro-Air-Vehicle, Brian J. Gamble
Experimental Analysis Of Propeller Interactions With A Flexible Wing Micro-Air-Vehicle, Brian J. Gamble
Theses and Dissertations
An investigation into the effects of the propeller slipstream on a flexible wing micro-air-vehicle (MAV) was conducted. The Air Force Research Lab, Munitions Directorate designed a man-portable MAV with a 24 in. wingspan and 6 in. root chord to be used for battle damage assessment and reconnaissance. Two wings have been developed for this MAV. One is a rigid carbon-fiber wing and the other consists of flexible parachute material attached to a carbon-fiber skeleton. Experimental methods were implemented to investigate propeller and wing interactions, characterizing torque and thrust requirements on the motor along with aerodynamic forces on the aircraft as …
Performance Analysis Of A Cooperative Search Algorithm For Multiple Unmanned Aerial Vehicles Under Limited Communication Conditions, Kevin M. Morris
Performance Analysis Of A Cooperative Search Algorithm For Multiple Unmanned Aerial Vehicles Under Limited Communication Conditions, Kevin M. Morris
Theses and Dissertations
This research investigates the impacts of realistic wireless communications upon a group of unmanned aerial vehicles (UAVs) utilizing a distributed search algorithm. The UAVs are used to survey an area for mobile targets and they require communication to cooperatively locate the targets. The mobile targets do not continually radiate energy, which exacerbates the search effort; a UAV could fly directly over a target and not detect it. A simulation of cooperative UAVs is implemented using the OPNET Modeler network simulation tool. The search performance of a group of UAVs is observed when communication range, data rate, and the number of …
Development Of Autonomous Unmanned Aerial Vehicle Platform: Modeling, Simulating, And Flight Testing, Nidal M. Jodeh
Development Of Autonomous Unmanned Aerial Vehicle Platform: Modeling, Simulating, And Flight Testing, Nidal M. Jodeh
Theses and Dissertations
The Advanced Navigation Technology (ANT) Center at the Air Force Institute of Technology (AFIT) conducts extensive research in advanced guidance, navigation, and control to exploit the full potential of autonomous Unmanned Aerial Vehicles (UAV). The research in this thesis describes a UAV research platform developed to support the ANT Center's goals. This platform is now the bedrock for UAV simulation and local flight test at AFIT. The research has three major components. The first component is development of a physical, inertial, and aerodynamic model representing an existing aircraft. A systematic analysis of the airframe leads to a complete geometric, inertial, …
Operator State Estimation For Adaptive Aiding In Uninhabited Combat Air Vehicles, Christopher A. Russell
Operator State Estimation For Adaptive Aiding In Uninhabited Combat Air Vehicles, Christopher A. Russell
Theses and Dissertations
This research demonstrated the first closed-loop implementation of adaptive automation using operator functional state in an operationally relevant environment. In the Uninhabited Combat Air Vehicle (UCAV) environment, operators can become cognitively overloaded and their performance may decrease during mission critical events. This research demonstrates an unprecedented closed-loop system, one that adaptively aids UCAV operators based on their cognitive functional state A series of experiments were conducted to 1) determine the best classifiers for estimating operator functional state, 2) determine if physiological measures can be used to develop multiple cognitive models based on information processing demands and task type, 3) determine …
Computational Aeroelastic Analysis Of Micro Air Vehicle With Experimentally Determined Modes, Joshua A. Stults
Computational Aeroelastic Analysis Of Micro Air Vehicle With Experimentally Determined Modes, Joshua A. Stults
Theses and Dissertations
A computational aeroelastic analysis of a micro air vehicle (MAV) is conducted. This MAV has a 24 inch wing span, and is designed for local area reconnaissance. Wind tunnel data for the MAV with a rigid carbon fiber wing and a flexible carbon fiber ribbed nylon wing are compared to CFD results incorporating static and dynamic deformations. We use laser vibrometry to determine the mode shapes of the flexible wing. From these shapes, CFD grid deformations are calculated as part of a closely-coupled aeroelastic solution method. The accuracy of MAV performance predictions using CFD with and without aeroelastic modeling is …
Analysis Of Online-Delaunay Navigation For Time Sensitive Targeting, David Chow
Analysis Of Online-Delaunay Navigation For Time Sensitive Targeting, David Chow
Theses and Dissertations
Given the drawbacks of leaving time-sensitive targeting (TST) strictly to humans, there is value to the investigation of alternative approaches to TST operations that employ autonomous systems. This paper accomplishes five things. First, it proposes a short-hop abbreviated routing paradigm (SHARP) - based on Delaunay triangulations (DT), ad-hoc communication, and autonomous control - for recognizing and engaging TSTs that, in theory, will improve upon persistence, the volume of influence, autonomy, range, and situational awareness. Second, it analyzes the minimum timeframe need by a strike (weapons enabled) aircraft to navigate to the location of a TST under SHARP. Third, it shows …
A Systems Architectural Model For Man-Packable/Operable Intelligence, Surveillance, And Reconnaissance Mini/Micro Aerial Vehicles, Cory A. Cooper, Matthew L. Ewoldt, Steaven A. Meyer, Edward W. Talley
A Systems Architectural Model For Man-Packable/Operable Intelligence, Surveillance, And Reconnaissance Mini/Micro Aerial Vehicles, Cory A. Cooper, Matthew L. Ewoldt, Steaven A. Meyer, Edward W. Talley
Theses and Dissertations
With the increase in both technology push and operational pull of mini/micro aerial vehicles (MAVs) within DoD organizations, an understanding of their interactions and capabilities is necessary. Many MAVs have already been developed for a specific usage and much speculation has been made on their future uses. Despite the growth of MAVs, there is currently no overarching systems architecture which would envelop and guide the DoD's MAV development efforts. The goal of this thesis is to apply sound systems engineering principals to develop a MAV architectural model describing their use in three separate but closely related mission areas: Over-the-Hill-Reconnaissance, Battle …
Decision Factors For Cooperative Multiple Warhead Uav Target Classification And Attack With Control Applications, Douglas D. Decker
Decision Factors For Cooperative Multiple Warhead Uav Target Classification And Attack With Control Applications, Douglas D. Decker
Theses and Dissertations
Autonomous wide area search, classification and attack using Unmanned Combat Air Vehicles (UCAVs) is considered. The wide area search and attack scenario is modeled, capturing important problem parameters related to environment, seeker, and munitions. Probabilistic analysis is used to formulate and analytically solve for various probabilities, including the probability of mission success. Two methods are utilized. The first examines the sub-events required for various events to occur. The second utilizes a Markov chain approach. General expressions are first obtained that are applicable to any assumed a priori distributions of targets and false targets. These expressions are subsequently applied to a …
Swarming Reconnaissance Using Unmanned Aerial Vehicles In A Parallel Discrete Event Simulation, Joshua J. Corner
Swarming Reconnaissance Using Unmanned Aerial Vehicles In A Parallel Discrete Event Simulation, Joshua J. Corner
Theses and Dissertations
Current military affairs indicate that future military warfare requires safer, more accurate, and more fault-tolerant weapons systems. Unmanned Aerial Vehicles (UAV) are one answer to this military requirement. Technology in the UAV arena is moving toward smaller and more capable systems and is becoming available at a fraction of the cost. Exploiting the advances in these miniaturized flying vehicles is the aim of this research. How are the UAVs employed for the future military? The concept of operations for a micro-UAV system is adopted from nature from the appearance of flocking birds, movement of a school of fish, and swarming …
Optimization Of Heterogeneous Uav Communications Using The Multiobjective Quadratic Assignment Problem, Mark P. Kleeman
Optimization Of Heterogeneous Uav Communications Using The Multiobjective Quadratic Assignment Problem, Mark P. Kleeman
Theses and Dissertations
The Air Force has placed a high priority on developing new and innovative ways to use Unmanned Aerial Vehicles (UAVs). The Defense Advanced Research Projects Agency (DARPA) currently funds many projects that deal with the advancement of UAV research. The ultimate goal of the Air Force is to use UAVs in operations that are highly dangerous to pilots, mainly the suppression of enemy air defenses (SEAD). With this goal in mind, formation structuring of autonomous or semi-autonomous UAVs is of future importance. This particular research investigates the optimization of heterogeneous UAV multi-channel communications in formation. The problem maps to the …
Cooperative Control Simulation Validation Using Applied Probability Theory, Christopher S. Schulz
Cooperative Control Simulation Validation Using Applied Probability Theory, Christopher S. Schulz
Theses and Dissertations
Several research simulations have been created to support development and refinement of teamed autonomous agents using decentralized cooperative control algorithms. Simulation is the necessary tool to evaluate the performance of decentralized cooperative control algorithms, however these simulations lack a method to validate their output. This research presents a method to validate the performance of a decentralized cooperative control simulation environment for an autonomous Wide Area Search Munition (WASM). Rigorous analytical methods for six wide area search and engagement scenarios involving Uniform, Normal, and Poisson distributions of N real targets and M false target objects are formulated to generate expected numbers …
Improving Uav Handling Qualities Using Time Delay Compensation, Andrew J. Thurling
Improving Uav Handling Qualities Using Time Delay Compensation, Andrew J. Thurling
Theses and Dissertations
This research investigated control loop time delay and its effect on UAV handling qualities. Compensation techniques to improve handling qualities in the presence of varying amounts of time delay were developed and analyzed. One technique was selected and successfully flight-tested on a UAV. Flight-testing occurred at a constant flight condition with varying levels of additional time delay introduced into the control loop. Research pilots performed a pitch tracking task and gave Cooper-Harper ratings and comments. Tracking errors were used as a quantitative measure of Pilot/Display/UAV system performance. Predictive pitch compensation was found to significantly reduce pilot workload and improve Cooper-Harper …
A Java Universal Vehicle Router In Support Of Routing Unmanned Aerial Vehicles, Robert W. Harder
A Java Universal Vehicle Router In Support Of Routing Unmanned Aerial Vehicles, Robert W. Harder
Theses and Dissertations
Unmanned Aerial Vehicles (UAVs) help the military gather information in times of peace and war. During a mission, typically 100 sites or more, a UAV will frequently be re-tasked to visit a pop-up threat, leaving the operator to determine the best way to finish the day's list of sites after the re-tasking. I develop a prototype application to serve the needs of a specific customer, the 11th Reconnaissance Squadron, by helping them preplan missions and dynamically re-task UAVs. This prototype application is built on a reusable airframe router called the core AFIT Router, which can later be added to more …
Dynamic Route Replanning And Retasking Of Unmanned Aerial Reconnaissance Vehicles, David E. Pritchard
Dynamic Route Replanning And Retasking Of Unmanned Aerial Reconnaissance Vehicles, David E. Pritchard
Theses and Dissertations
Many common operational situations in High Altitude Endurance (HAE) UAV reconnaissance necessitate more direct human involvement in the aircraft control process than is currently acknowledged or allowed. The In-Flight Replanning System (IFRS) is developed as a notional solution, with the Global Hawk HAE UAV as the reconnaissance system model. Problematic scenarios for current in-flight mission replanning systems are presented and revisited with the IFRS, demonstrating improved replanning results.