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Full-Text Articles in Aerospace Engineering

Urban Flow And Small Unmanned Aerial System Operations In The Built Environment, Kevin A. Adkins Feb 2019

Urban Flow And Small Unmanned Aerial System Operations In The Built Environment, Kevin A. Adkins

Kevin A. Adkins, PhD

The Federal Aviation Administration (FAA) has put forth a set of regulations (Part 107) that govern small unmanned aerial system (sUAS) operations. These regulations restrict unmanned aircraft (UA) from flying over people and their operation to within visual line of sight (VLOS). However, as new applications for unmanned aerial systems (UAS) are discovered, their capabilities improve, and regulations evolve, there is an increasing desire to undertake urban operations, such as urban air mobility, package delivery, infrastructure inspection, and surveillance. This built environment poses new weather hazards that include enhanced wind shear and turbulence. The smaller physical dimensions, lower mass and …


Validation And Verification Flight Tests Of Fixed-Wing Collaborative Uass With High Speeds And High Inertias, A Ram (Bella) Kim Jun 2018

Validation And Verification Flight Tests Of Fixed-Wing Collaborative Uass With High Speeds And High Inertias, A Ram (Bella) Kim

A Ram (Bella) Kim

The research objective for this work is to validate and verify guidance, navigation, and control algorithms that are designed for fixed-wing collaborative unmanned aerial systems (UASs) in unstructured environments. A biologically-inspired swarm control theory provides a framework to distribute sensor payloads between several smaller and less complex agents that have local interactions. Controller design and flight testing of large UASs with high speeds and high inertias holding a formation in a dynamically changing environment and in the presence of external disturbances is complex and requires advanced planning and safety measures. Verification and validation flight tests were conducted using a fixed-wing …


Control Of Multi-Agent Collaborative Fixed-Wing Uass In Unstructured Environment, A Ram (Bella) Kim Jun 2018

Control Of Multi-Agent Collaborative Fixed-Wing Uass In Unstructured Environment, A Ram (Bella) Kim

A Ram (Bella) Kim

Swarms of unmanned aircraft are the inevitable future of the aerospace industry. In recent years, swarming robots and aircraft have been a subject of much interest; however, many research projects make impractical assumptions such as point mass dynamics with no aerodynamic effects for aircraft models, and most works stop short of fully validating their methods via flight testing. This work presents a proximity based guidance, navigation, and control of multi-agent fixed-wing unmanned aerial systems in an unstructured environment. A scalable swarm navigation method is developed using adaptive moving mesh partial differential equations controlled by the free energy heat flow equation. …


Validation And Verification Of Gnc For Large Fixed-Wing Unmanned Aerial System In Unstructured And Noisy Environment, A Ram (Bella) Kim Jun 2018

Validation And Verification Of Gnc For Large Fixed-Wing Unmanned Aerial System In Unstructured And Noisy Environment, A Ram (Bella) Kim

A Ram (Bella) Kim

The impact of high update rate on the disparity in eigenvalues of the auto-correlation matrix, along with slow convergence and reduced stability of numerical analysis are well studied. However, the impact of high update rates of autopilots on the performance of unmanned aircraft has been ignored due to the intrinsic limitations of COTS autopilots
computation power. Although MEMS based IMUs have very high update rates, the majority of existing UAS autopilot system processing power is limited to 20 Hz. In this work, the challenges and processes for developing and flight test validating an autonomous flight controller for a large 30-kg …


Space Operations In The Suborbital Space Flight Simulator And Mission Control Center: Lessons Learned With Xcor Lynx, Pedro Llanos, Christopher Nguyen, David Williams, Kim O. Chambers Ph.D., Erik Seedhouse, Robert Davidson May 2018

Space Operations In The Suborbital Space Flight Simulator And Mission Control Center: Lessons Learned With Xcor Lynx, Pedro Llanos, Christopher Nguyen, David Williams, Kim O. Chambers Ph.D., Erik Seedhouse, Robert Davidson

Pedro J. Llanos (www.AstronauticsLlanos.com)

This study was conducted to better understand the performance of the XCOR Lynx vehicle. Because the Lynx development was halted, the best knowledge of vehicle dynamics can only be found through simulator flights. X-Plane 10 was chosen for its robust applications and accurate portrayal of dynamics on a vehicle in flight. The Suborbital Space Flight Simulator (SSFS) and Mission Control Center (MCC) were brought to the Applied Aviation Sciences department in fall 2015 at Embry-Riddle Aeronautical University, Daytona Beach campus. This academic and research tool is a department asset capable of providing multiple fields of data about suborbital simulated flights. …


Synthetic Jet Actuator-Based Aircraft Tracking Using A Continuous Robust Nonlinear Control Strategy, N. Ramos-Pedroza, W. Mackunis, M. Reyhanoglu May 2018

Synthetic Jet Actuator-Based Aircraft Tracking Using A Continuous Robust Nonlinear Control Strategy, N. Ramos-Pedroza, W. Mackunis, M. Reyhanoglu

William MacKunis

A robust nonlinear control law that achieves trajectory tracking control for unmanned aerial vehicles (UAVs) equipped with synthetic jet actuators (SJAs) is presented in this paper. A key challenge in the control design is that the dynamic characteristics of SJAs are nonlinear and contain parametric uncertainty. The challenge resulting from the uncertain SJA actuator parameters is mitigated via innovative algebraic manipulation in the tracking error system derivation along with a robust nonlinear control law employing constant SJA parameter estimates. A key contribution of the paper is a rigorous analysis of the range of SJA actuator parameter uncertainty within which asymptotic …


Analysis And Verification Of Cost-Effective Design Modifications To Commercially Available Fixed-Wing Unmanned Aerial Vehicle To Improve Performance, Stability And Control Characteristics, And Structural Integrity, A Ram (Bella) Kim Jan 2018

Analysis And Verification Of Cost-Effective Design Modifications To Commercially Available Fixed-Wing Unmanned Aerial Vehicle To Improve Performance, Stability And Control Characteristics, And Structural Integrity, A Ram (Bella) Kim

A Ram (Bella) Kim

In this work, several cost-effective design modifications were made to a commercially available fixed-wing unmanned aerial vehicle in order to improve overall performance and reliability. These modifications included the addition of 3D-printed winglets to improve aerodynamic performance, applying fiberglass reinforcement to areas of structural concern, the addition of rudder control surfaces for improved control authority, increasing the length of the empennage booms for both stability and control improvements, and the addition of dorsal fins to improve vertical fin stall characteristics. Design methodology and manufacturing processes were outlined, a cost breakdown was presented, and results from dynamic analysis were validated through …


Dynamic Modeling And Simulation Of A Quadcopter With Motor Dynamics, A Ram (Bella) Kim Jan 2017

Dynamic Modeling And Simulation Of A Quadcopter With Motor Dynamics, A Ram (Bella) Kim

A Ram (Bella) Kim

Increased usage of quadcopters as an embedded system has raised the necessity of developing high quality dynamic models for designing controllers and simulations. In this work, a dynamic model was developed for a quadcopter platform by conducting experiments for estimating the moments of inertia and for determining motor dynamics. The dynamic model consisted of equations of motions derived from Newton and Euler's approach. Moments of inertia were estimated by operating a bifilar pendulum test. The motor dynamics were developed using a custom built test bed. The thrust, torque, voltage, and current were recorded in order to develop an adaptive dynamic …


Guidance Of Multi-Agent Fixed-Wing Aircraft Using A Moving Mesh Method, A Ram (Bella) Kim Oct 2016

Guidance Of Multi-Agent Fixed-Wing Aircraft Using A Moving Mesh Method, A Ram (Bella) Kim

A Ram (Bella) Kim

This paper presents a novel guidance logic for multi-agent fixed-wing unmanned aerial systems using a moving mesh method. The moving mesh method is originally designed for use in the adaptive numerical solution of partial differential equations, where a high proportion of mesh points are placed in the regions of large solution variations and few points in the rest of the domain. In this work, the positions of the aircraft are considered as mesh nodes connected to form a triangular mesh in two spatial dimensions. The outer aircraft positions are planned with the reference point algorithm. This logic provides the outer …


Comment On Faa Rule Revision - Transport Category Aircraft, Paul F. Eschenfelder, Valter Battistoni Nov 2015

Comment On Faa Rule Revision - Transport Category Aircraft, Paul F. Eschenfelder, Valter Battistoni

Paul F. Eschenfelder

No abstract provided.


Scheduling Algorithm Development For An Open Source Software And Open Hardware Spacecraft, Calvin Bina, Jeremy Straub, Ronald Marsh Apr 2015

Scheduling Algorithm Development For An Open Source Software And Open Hardware Spacecraft, Calvin Bina, Jeremy Straub, Ronald Marsh

Jeremy Straub

The efficacy of each type of scheduler is assessed rela-tive to the goal of having a time and resource efficient scheduling algorithm. The scheduler must ensure suc-cessful spacecraft operations and maximize the perfor-mance of tasks relative to performance constraints and their respective due dates.


Designing An Intelligent Attitude Determination And Control System (Adcs), Michael Wegerson, Matt Partridge, Nathan Crocker, David Schindele, Broc Friend, Levi Lewis, Ben Johnson, Jeremy Straub, Ronald Marsh Apr 2015

Designing An Intelligent Attitude Determination And Control System (Adcs), Michael Wegerson, Matt Partridge, Nathan Crocker, David Schindele, Broc Friend, Levi Lewis, Ben Johnson, Jeremy Straub, Ronald Marsh

Jeremy Straub

CubeSat spacecraft have been shown to provide significant cost [1], research [1] and educational benefits [2]. Prior work at UND has demonstrated the efficacy of this form factor of craft for asteroid as-sessment activities [3] and onboard image processing [4]. Work is al-so ongoing to develop a low-cost framework [5] for CubeSat devel-opment to enable activities at UND and at other locations.


Reducing Magneto-Inductive Positioning Errors In A Metal-Rich Indoor Environment, Orfeas Kypris, Traian Abrudan, Andrew Markham Jan 2015

Reducing Magneto-Inductive Positioning Errors In A Metal-Rich Indoor Environment, Orfeas Kypris, Traian Abrudan, Andrew Markham

Orfeas Kypris

Ferrous objects distort magnetic fields and can significantly increase magneto-inductive positioning errors in indoor environments. In this work, we use image theory in order to formulate an analytical channel model for the magnetic field of a quasi-static magnetic dipole positioned above a perfectly conducting half-space. The proposed model can be used to compensate for the distorting effects that metallic reinforcement bars (rebars) impose on the magnetic field of a magneto-inductive transmitter node in an indoor environment. Good agreement is observed between the analytical solution and numerical solutions obtained from 2-D finite element simulations when the transmitter node is located more …


Investigation Of An Autonomous Landing Sensor For Unmanned Aerial Systems, A Ram (Bella) Kim Jan 2014

Investigation Of An Autonomous Landing Sensor For Unmanned Aerial Systems, A Ram (Bella) Kim

A Ram (Bella) Kim

This research focused on characterizing the precision, reliability, sensitivity, and uncertainty of an autonomous landing sensor. Currently, the most dangerous flight phase for autonomous aircraft is the landing and takeoff segments, accounting for almost 70% of crashes. This research analyzes the effects of the color and roughness of the landing surface, fog, ice, and varying aircraft angles on the performance of an automated landing sensor. An investigation of suitable sensors was performed and the Dimetix FLS-C30 laser altimeter was selected for testing. The standard deviation and uncertainty of each condition was found and compared. It was determined that surface color, …


Rocket Flight Path, Jamie L. Waters Jan 2014

Rocket Flight Path, Jamie L. Waters

Jamie L Waters

This project uses Newton’s Second Law of Motion, Euler’s method, basic physics, and basic calculus to model the flight path of a rocket. From this project, one can find the height and velocity at any point from launch to the maximum altitude, apogee. Once complete this can be compared to what the actual values were to see if the method is a plausible way of estimation. The rocket used in this project is modeled after Bullistic-1 which was launched by the Society of Aeronautics and Rocketry at the University of South Florida.


Dynamic Surface Control Of Constrained Hypersonic Flight Models With Parameter Estimation And Actuator Compensation, Bin Xu Jan 2014

Dynamic Surface Control Of Constrained Hypersonic Flight Models With Parameter Estimation And Actuator Compensation, Bin Xu

Bin Xu

In this paper, the robust adaptive controller is investigated for the longitudinal dynamics of a generic hypersonic flight vehicle. The proposed methodology addresses the issue of controller design and stability analysis with respect to parametric model uncertainty and input saturations for the control-oriented model. The velocity and attitude subsystems are transformed into the linearly parameterized form. Based on the parameter projection estimation, the dynamic inverse control is proposed via the back-stepping scheme. In order to avoid the problem of “explosion of complexity,” by introducing a first-order filtering of the synthetic input at each step, the dynamic surface control is designed. …


Open Beyond Orbit: Using The Designs From The Open Prototype For Educational Nanosats Outside Of Earth Orbit, Jeremy Straub Jun 2013

Open Beyond Orbit: Using The Designs From The Open Prototype For Educational Nanosats Outside Of Earth Orbit, Jeremy Straub

Jeremy Straub

This paper presents an overview of the Open Prototype for Educational NanoSats (OPEN) and its prospective use in interplanetary missions. OPEN is framework to facilitate the low-cost creation of CubeSat-class spacecraft via using publically available (provided by the OPEN project) de- signs, software, fabrication instructions and test plans. The base open configuration is designed to be able to be produced with a parts budget of under $5,000. Despite this low cost, it is a very ro- bust spacecraft (with capabilities meeting or exceeding many of the vendor-kit solutions which cost eight-or-more times this amount).

Two approaches for using the OPEN …


Spatial Computing In An Orbital Environment: An Exploration Of The Unique Constraints Of This Special Case To Other Spatial Computing Environments, Jeremy Straub May 2013

Spatial Computing In An Orbital Environment: An Exploration Of The Unique Constraints Of This Special Case To Other Spatial Computing Environments, Jeremy Straub

Jeremy Straub

The creation of an orbital services model (where spacecraft expose their capabilities for use by other spacecraft as part of a service-for-hire or barter system) requires effective determination of how to best transmit information between the two collaborating spacecraft. Existing approaches developed for ad hoc networking (e.g., wireless networks with users entering and departing in a pseudo-random fashion) exist; however, these fail to generate optimal solutions as they ignore a critical piece of available information. This additional piece of information is the orbital characteristics of the spacecraft. A spacecraft’s orbit is nearly deterministic if the magnitude and direction of its …


A Human Proximity Operations System Test Case Validation Approach, Justin Huber, Jeremy Straub Mar 2013

A Human Proximity Operations System Test Case Validation Approach, Justin Huber, Jeremy Straub

Jeremy Straub

A Human Proximity Operations System (HPOS) poses numerous risks in a real world environment. These risks range from mundane tasks such as avoiding walls and fixed obstacles to the critical need to keep people and processes safe in the context of the HPOS’s situation-specific decision making. Validating the performance of an HPOS, which must operate in a real-world environment, is an ill posed problem due to the complexity that is introduced by erratic (non-computer) actors. In order to prove the HPOS’s usefulness, test cases must be generated to simulate possible actions of these actors, so the HPOS can be shown …


Multi-Tier Exploration Concept Demonstration Mission, Jeremy Straub May 2012

Multi-Tier Exploration Concept Demonstration Mission, Jeremy Straub

Jeremy Straub

A multi-tier, multi-craft mission architecture has been proposed but, despite its apparent promise, limited use and testing of the architecture has been conducted. This paper proposes and details a mission concept and its implementation for testing this architecture in the terrestrial environment. It is expected that this testing will allow significant refinement of the proposed architecture as well as providing data on its suitability for use in both terrestrial and extra-terrestrial applications. Logistical and technical challenges with this testing are discussed.


Adaptive Kriging Controller Design For Hypersonic Flight Vehicle Via Back-Stepping, Bin Xu Jan 2012

Adaptive Kriging Controller Design For Hypersonic Flight Vehicle Via Back-Stepping, Bin Xu

Bin Xu

No abstract provided.


Direct Neural Discrete Control Of Hypersonic Flight Vehicle, Bin Xu Jan 2012

Direct Neural Discrete Control Of Hypersonic Flight Vehicle, Bin Xu

Bin Xu

No abstract provided.


Development Of A Novel Methodology For Indoor Emission Source Identification, Kwanghoon Han Mar 2011

Development Of A Novel Methodology For Indoor Emission Source Identification, Kwanghoon Han

Kwanghoon Han

The objective of this study was to develop and evaluate a methodology to identify individual sources of emissions based on the measurements of mixed air samples and the emission signatures of individual materials previously determined by Proton Transfer Reaction-Mass Spectrometry (PTR-MS), an on-line analytical device. The methodology based on signal processing principles was developed by employing the method of multiple regression least squares (MRLS) and a normalization technique. Samples of nine typical building materials were tested individually and in combination, including carpet, ceiling material, gypsum board, linoleum, two paints, polyolefine, PVC and wood. Volatile Organic Compound (VOC) emissions from each …


Modeling And Control Of Space Vehicles With Fuel Slosh Dynamics, Mahmut Reyhanoglu Feb 2011

Modeling And Control Of Space Vehicles With Fuel Slosh Dynamics, Mahmut Reyhanoglu

Mahmut Reyhanoglu

"Ever since the launch of the early high-efficiency rockets, controlling liquid fuel slosh within a launch vehicle has been a major design concern. Moreover, with today's large and complex spacecraft, a substantial mass of fuel is necessary to place them into orbit and to perform orbital maneuvers."--From the book's introduction.


Adaptive Discrete-Time Controller Design With Neural Network For Hypersonic Flight Vehicle Via Back-Stepping, Bin Xu Jan 2011

Adaptive Discrete-Time Controller Design With Neural Network For Hypersonic Flight Vehicle Via Back-Stepping, Bin Xu

Bin Xu

In this article, the adaptive neural controller in discrete time is investigated for the longitudinal dynamics of a generic hypersonic flight vehicle. The dynamics are decomposed into the altitude subsystem and the velocity subsystem. The altitude subsystem is transformed into the strict-feedback form from which the discrete-time model is derived by the first-order Taylor expansion. The virtual control is designed with nominal feedback and neural network (NN) approximation via back-stepping. Meanwhile, one adaptive NN controller is designed for the velocity subsystem. To avoid the circular construction problem in the practical control, the design of coefficients adopts the upper bound instead …


Adaptive Neural Control Based On Hgo For Hypersonic Flight Vehicles, Bin Xu Jan 2011

Adaptive Neural Control Based On Hgo For Hypersonic Flight Vehicles, Bin Xu

Bin Xu

This paper describes the design of adaptive neural controller for the longitudinal dynamics of a generic hypersonic flight vehicle (HFV) which are decomposed into two functional systems, namely the altitude subsystem and the velocity subsystem. For each subsystem, one adaptive neural controller is investigated based on the normal output-feedback formulation. For the altitude subsystem, the high gain observer (HGO) is taken to estimate the unknown newly defined states. Only one neural network (NN) is employed to approximate the lumped uncertain system nonlinearity during the controller design which is considerably simpler than the ones based on back-stepping scheme with the strict-feedback …


Task Allocation For Multi-Spacecraft Cooperation Based On Estimation Of Distribution Algorithm, Bin Xu Jan 2011

Task Allocation For Multi-Spacecraft Cooperation Based On Estimation Of Distribution Algorithm, Bin Xu

Bin Xu

One two-stage task allocation strategy is proposed for multi-spacecraft cooperation during the long-range orbit transfer with two impulses. This paper focuses on the task value maximum and cost minimum optimization by assigning spacecraft to different task. At the first stage time and energy cost are considered based on the spacecraft dynamics. The optimization result is together with the target value as the factor for the task allocation model at the second stage. The optimization is processed separately in continuous and discrete time domain with estimation of distribution algorithm (EDA). Different task allocation mode is formulated and the strategy is verified …


Composite Control Based On Optimal Torque Control And Adaptive Kriging Control For The Crab Rover, Bin Xu Jan 2011

Composite Control Based On Optimal Torque Control And Adaptive Kriging Control For The Crab Rover, Bin Xu

Bin Xu

Terrainability is mostly dependant on the suspension mechanism and the control of a space rover. For the six wheeled CRAB rover, this paper presents the composite control design with torque control and adaptive Kriging control to improve the terrainability, somewhat related to minimizing heel slip. As CRAB is moving slowly, the torque control is processed by minimizing the variance of the required friction coefficient based on the static model. Adaptive Kriging control is used to track the commanded velocity. The system uncertainty is compensated by Kriging estimation based on the velocity dynamics. Experiment results with two different tires show the …


Adaptive Hypersonic Flight Control Via Back-Stepping And Kriging Estimation, Bin Xu Jan 2011

Adaptive Hypersonic Flight Control Via Back-Stepping And Kriging Estimation, Bin Xu

Bin Xu

This paper investigates the adaptive Kriging controller for the longitudinal dynamics of a generic hypersonic flight vehicle (HFV). For the altitude subsystem, the dynamics are transformed into the strict-feedback form where the backstepping scheme is employed. Considering the nonlinearity of the dynamics, the nominal feedback is included in the controller while Kriging system is designed to estimate the uncertainty. With the proposed controller, the almost surely bounded stability is guaranteed. The simulation study is presented to show the effectiveness of the proposed control approach.


Determination Of Material Emission Signatures By Ptr-Ms And Their Correlations With Odor Assessments By Human Subjects, Kwanghoon Han Apr 2010

Determination Of Material Emission Signatures By Ptr-Ms And Their Correlations With Odor Assessments By Human Subjects, Kwanghoon Han

Kwanghoon Han

The objectives of this study were to determine volatile organic compound (VOC) emission signatures of nine typical building materials by using proton transfer reaction-mass spectrometry (PTR-MS) and to explore the correlation between the PTR-MS measurements and the measurements of acceptability by human subjects. VOC emissions from each material were measured in a 50-l small-scale chamber. Chamber air was sampled by PTR-MS to determine emission signatures. Sorbent tube sampling and TD-GC/MS analysis were also performed to identify the major VOCs emitted and to compare the resulting data with the PTR-MS emission signatures. The data on the acceptability of air quality assessed …