Assessment Of Asymmetric Flight On Solar Uas,
2016
California Polytechnic State University, San Luis Obispo
Assessment Of Asymmetric Flight On Solar Uas, Eric Belfield
Master's Theses
An investigation was conducted into the feasibility of using an unconventional flight technique, asymmetric flight, to improve overall efficiency of solar aircraft. In this study, asymmetric flight is defined as steady level flight in a non-wings-level state in- tended to improve solar incidence angle. By manipulating aircraft orientation through roll angle, solar energy collection is improved but aerodynamic efficiency is worsened due to the introduction of additional trim drag. A point performance model was devel- oped to investigate the trade-off between improvement in solar energy collection and additional drag associated with asymmetric flight. A mission model with a focus on …
A Novel Approach For Controlled Deorbiting And Reentry Of Small Spacecraft,
2016
NASA Launch Services Program
A Novel Approach For Controlled Deorbiting And Reentry Of Small Spacecraft, Larry H. Fineberg, Justin Treptow, Timothy Bass, Scott Clark, Yusef Johnson, Bradley Poffenberger
Space Traffic Management Conference
No abstract provided.
Adaptive Estimation And Heuristic Optimization Of Nonlinear Spacecraft Attitude Dynamics,
2016
Air Force Institute of Technology
Adaptive Estimation And Heuristic Optimization Of Nonlinear Spacecraft Attitude Dynamics, Joshuah A. Hess
Theses and Dissertations
For spacecraft conducting on-orbit operations, changes to the structure of the spacecraft are not uncommon. These planned or unanticipated changes in inertia properties couple with the spacecraft's attitude dynamics and typically require estimation. For systems with time-varying inertia parameters, multiple model adaptive estimation (MMAE) routines can be utilized for parameter and state estimates. MMAE algorithms involve constructing a bank of recursive estimators, each assuming a different hypothesis for the systems dynamics. This research has three distinct, but related, contributions to satellite attitude dynamics and estimation. In the first part of this research, MMAE routines employing parallel banks of unscented attitude …
Optimal Control Of An Uninhabited Loyal Wingman,
2016
Air Force Institute of Technology
Optimal Control Of An Uninhabited Loyal Wingman, Clay J. Humphreys
Theses and Dissertations
As researchers strive to achieve autonomy in systems, many believe the goal is not that machines should attain full autonomy, but rather to obtain the right level of autonomy for an appropriate man-machine interaction. A common phrase for this interaction is manned-unmanned teaming (MUM-T), a subset of which, for unmanned aerial vehicles, is the concept of the loyal wingman. This work demonstrates the use of optimal control and stochastic estimation techniques as an autonomous near real-time dynamic route planner for the DoD concept of the loyal wingman. First, the optimal control problem is formulated for a static threat environment and …
Improving Real-World Performance Of Vision Aided Navigation In A Flight Environment,
2016
Air Force Institute of Technology
Improving Real-World Performance Of Vision Aided Navigation In A Flight Environment, Donald T. Venable
Theses and Dissertations
The motivation of this research is to fuse information from an airborne imaging sensor with information extracted from satellite imagery in order to provide accurate position when GPS is unavailable for an extended duration. A corpus of existing geo-referenced satellite imagery is used to create a key point database. A novel algorithm for recovering coarse pose using by comparing key points extracted from the airborne imagery to the reference database is developed. This coarse position is used to bootstrap a local-area geo-registration algorithm, which provides GPS-level position estimates. This research derives optimizations for existing local-area methods for operation in flight …
A Hybrid Optimization Technique Applied To The Intermediate-Target Optimal Control Problem,
2016
Air Force Institute of Technology
A Hybrid Optimization Technique Applied To The Intermediate-Target Optimal Control Problem, Clay J. Humphreys, Richard G. Cobb, David R. Jacques, Jonah A. Reeger
Faculty Publications
The DoD has introduced the concept of Manned-Unmanned Teaming, a subset of which is the loyal wingman. Optimal control techniques have been proposed as a method for rapidly solving the intermediate-target (mid-point constraint) optimal control problem. Initial results using direct orthogonal collocation and a gradient-based method for solving the resulting nonlinear program reveals a tendency to converge to or to get `stuck’ in locally optimal solutions. The literature suggested a hybrid technique in which a particle swarm optimization is used to quickly find a neighborhood of a more globally minimal solution, at which point the algorithm switches to a gradient-based …
Vision-Aided Navigation For Autonomous Vehicles Using Tracked Feature Points,
2016
Embry-Riddle Aeronautical University
Vision-Aided Navigation For Autonomous Vehicles Using Tracked Feature Points, Ahmed Saber Soliman Sayem
Doctoral Dissertations and Master's Theses
This thesis discusses the evaluation, implementation, and testing of several navigation algorithms and feature extraction algorithms using an inertial measurement unit (IMU) and an image capture device (camera) mounted on a ground robot and a quadrotor UAV. The vision-aided navigation algorithms are implemented on data-collected from sensors on an unmanned ground vehicle and a quadrotor, and the results are validated by comparison with GPS data. The thesis investigates sensor fusion techniques for integrating measured IMU data with information extracted from image processing algorithms in order to provide accurate vehicle state estimation. This image-based information takes the forms of features, such …
Autonomous Formation Flying And Proximity Operations Using Differential Drag On The Mars Atmosphere,
2016
California Polytechnic State University, San Luis Obispo
Autonomous Formation Flying And Proximity Operations Using Differential Drag On The Mars Atmosphere, Andres Eduardo Villa
Master's Theses
Due to mass and volume constraints on planetary missions, the development of control techniques that do not require fuel are of big interest. For those planets that have a dense enough atmosphere, aerodynamic drag can play an important role. The use of atmospheric differential drag for formation keeping was first proposed by Carolina L. Leonard in 1986, and has been proven to work in Earth atmosphere by many missions. Moreover, atmospheric drag has been used in the Mars atmosphere as aerobraking technique to decelerate landing vehicles, and to circularize the orbit of the spacecraft. Still, no literature was available related …
A Solution To The Circular Restricted N Body Problem In Planetary Systems,
2016
California Polytechnic State University, San Luis Obispo
A Solution To The Circular Restricted N Body Problem In Planetary Systems, Jay R. Iuliano
Master's Theses
This thesis is a brief look at a new solution to a problem that has been approached in many different ways in the past - the N body problem. By focusing on planetary systems, satellite dynamics can be modeled in a fashion similar to the Circular Restricted Three Body Problem (CR3BP) with the Circular Restricted N Body Problem (CRNBP). It was found that this new formulation of the dynamics can then utilize the tools created from all the research into the CR3BP to reassess the possibility of different complex trajectories in systems where there are more than just two large …
Time-Of-Flight Based Sonic Speed Measurements For Cold Gas Thruster Development,
2016
University of Arkansas, Fayetteville
Time-Of-Flight Based Sonic Speed Measurements For Cold Gas Thruster Development, Brandon W. Kempf
Mechanical Engineering Undergraduate Honors Theses
The purpose of this thesis is to explore an experiment developed for validating the usage of a gaseous solution of water and propylene glycol for cold gas propulsion. The experiment involves a “Time of Flight” method of calculating the speed of sound in the gas and the corresponding specific heat ratio using a copper tube, two MEMS microphones, a piezoelectric speaker, and data-acquisition hardware. The experiment was calibrated using the known thermodynamic properties of air. The accuracy of the experiment was found to be within 0.6% for calculations of the speed of sound in air and within 1.0% of the …
A Radial Basis Function Method For Solving Optimal Control Problems.,
2016
University of Louisville
A Radial Basis Function Method For Solving Optimal Control Problems., Hossein Mirinejad
Electronic Theses and Dissertations
This work presents two direct methods based on the radial basis function (RBF) interpolation and arbitrary discretization for solving continuous-time optimal control problems: RBF Collocation Method and RBF-Galerkin Method. Both methods take advantage of choosing any global RBF as the interpolant function and any arbitrary points (meshless or on a mesh) as the discretization points. The first approach is called the RBF collocation method, in which states and controls are parameterized using a global RBF, and constraints are satisfied at arbitrary discrete nodes (collocation points) to convert the continuous-time optimal control problem to a nonlinear programming (NLP) problem. The …
Magneto-Rheological Fluid Device As Artificial Feel Force System On Aircraft Control Stick,
2016
Embry-Riddle Aeronautical University
Magneto-Rheological Fluid Device As Artificial Feel Force System On Aircraft Control Stick, Vignesh Manoharan
Doctoral Dissertations and Master's Theses
The conventional feel system in any aircraft occupies large space in the cockpit and has complicated designs. The primary objective of this research is to develop an artificial feel force system that can overcome some drawbacks of the current feel force system. A novel feel system using magneto-rheological (MR) fluid is constructed to precisely control the shear stress under the magnetic field. To validate the functionality of the MR artificial feel system, the final system is fabricated and multiple tests are performed to acquire force-velocity characteristics that are compared to the mathematical model derived. In addition, the reference model of …
Utilization Of Trss To Assist Pilot’S Decision Making Process During Critical Runway Operations.,
2016
Minnesota State University, Mankato
Utilization Of Trss To Assist Pilot’S Decision Making Process During Critical Runway Operations., Nihad E. Daidzic
Aviation Department Publications
No abstract provided.
Nonlinear Flight Control Design Using Backstepping Methodology,
2016
Old Dominion University
Nonlinear Flight Control Design Using Backstepping Methodology, Thanh Trung Tran
Mechanical & Aerospace Engineering Theses & Dissertations
The subject of nonlinear flight control design using backstepping control methodology is investigated in the dissertation research presented here. Control design methods based on nonlinear models of the dynamic system provide higher utility and versatility because the design model more closely matches the physical system behavior. Obtaining requisite model fidelity is only half of the overall design process, however. Design of the nonlinear control loops can lessen the effects of nonlinearity, or even exploit nonlinearity, to achieve higher levels of closed-loop stability, performance, and robustness. The goal of the research is to improve control quality for a general class of …
Real-Time Implementation Of Vision-Aided Monocular Navigation For Small Fixed-Wing Unmanned Aerial Systems,
2016
Air Force Institute of Technology
Real-Time Implementation Of Vision-Aided Monocular Navigation For Small Fixed-Wing Unmanned Aerial Systems, Timothy I. Machin
Theses and Dissertations
The goal of this project was to develop and implement algorithms to demonstrate real-time positioning of a UAV using a monocular camera combined with previously collected orthorectified imagery. Unlike previous tests, this project did not utilize a full inertial navigation system (INS) for attitude, but instead had to rely on the attitude obtained by inexpensive commercial off-the-shelf (COTS) autopilots. The system consisted of primarily COTS components and open-source software, and was own over Camp Atterbury, IN for a sequence of flight tests in Fall 2015. The system obtained valid solutions over much of the flight path, identifying features in the …
Visual-Ins Using A Human Operator And Converted Measurements,
2016
Air Force Institute of Technology
Visual-Ins Using A Human Operator And Converted Measurements, Turner J. Montgomery
Theses and Dissertations
A method human operated INS aiding is explored in which the pilot identifies and tracks a ground feature of unknown position over a short measurement epoch using an E/O sensor. One then refers to Visual-INS. In contrast to current research trends, a human operator is entrusted with visually tracking the ground feature. In addition, a less conventional measurement linearization technique is applied to generate “converted” measurements. A linear regression algorithm is then applied to the converted measurements providing an estimate of the INS horizontal velocity error and accelerometer biases. At the completion of the measurement epoch, the INS is corrected …
Evaluation Of Verification Approaches Applied To A Nonlinear Control System,
2016
Air Force Institute of Technology
Evaluation Of Verification Approaches Applied To A Nonlinear Control System, Kerianne H. Gross
Theses and Dissertations
As the demand for increasingly complex and autonomous systems grows, designers may consider computational and artificial intelligence methods for more advanced, re- active control. While the performance gained by such increasingly intelligent systems may be superior to traditional control techniques, the lack of transparency in the systems and opportunity for emergent behavior limits their application in the field. New verification and validation methods must be developed to ensure the output of such controllers do not put the system or any people interacting with it in danger. This challenge was highlighted by the former Air Force Chief Scientist in his 2010 …
Investigation Into Active Spanwise Camber Deformation On The Lateral Stability And Roll Control Of The X-56a Compared To Conventional Ailerons,
2016
Air Force Institute of Technology
Investigation Into Active Spanwise Camber Deformation On The Lateral Stability And Roll Control Of The X-56a Compared To Conventional Ailerons, Eric T. Yerly
Theses and Dissertations
"This research compares the stability and roll characteristics of an X-56A using AFRL’s Variable Camber Complaint wing technology to actively change wing camber compared to conventional ailerons deflected at set angles. An analysis of the stability and roll characteristics was modeled using a 3-D vortex lattice theory simulation, and that data was compared to wind tunnel testing to verify and validate the model results. Wind tunnel data was collected using 19 inch 3-D printed scale models with wings fabricated with a pre-determined percentage of camber deformation, as well as models with fixed aileron deflections. The full span model changed camber …
Cognitive Loading, Affect Regulation And Aerodynamic Considerations In Uninhabited Aerial Vehicle Systems Refueling Operations,
2016
Embry-Riddle Aeronautical University
Cognitive Loading, Affect Regulation And Aerodynamic Considerations In Uninhabited Aerial Vehicle Systems Refueling Operations, Sam Holley, Ian R. Mcandrew
Publications
Factors influencing aerodynamics involved in aerial refueling illustrate the potential for specialist operators to manage these operations for remotely piloted vehicles. The authors review aerodynamic characteristics of uninhabited aerial systems during refueling, drogue and boom design and associated flight dynamics, cognitive factors associated with control transfer and refueling, and affective components and their influence on decision making and operator performance. Attention is directed to cognitive loading and encoding challenges, with considerations for hippocampal mapping and hemispheric asymmetry. Implications for system state awareness are examined. Advantages for specially trained refueling pilot operators are discussed and recommendations given for areas of concentration.
Determining The Runway Point-Of-No-Return For Landing Roll Go-Around In Transport Category Airplanes,
2016
Minnesota State University, Mankato
Determining The Runway Point-Of-No-Return For Landing Roll Go-Around In Transport Category Airplanes, Nihad E. Daidzic
Aviation Department Publications
No abstract provided.
