Indirect Model Reference Adaptive Control With Online Parameter Estimation,
2021
Embry-Riddle Aeronautical University
Indirect Model Reference Adaptive Control With Online Parameter Estimation, Jovan Bruce
Doctoral Dissertations and Master's Theses
Over the years, parameter estimation has focused on approaches in both the time and frequency domains. The parameter estimation process is particularly important for aerospace vehicles that have considerable uncertainty in the model parameters, as might be the case with unmanned aerial vehicles (UAVs). This thesis investigates the use of an Indirect Model Reference Adaptive Controller (MRAC) to provide online, adaptive estimates of uncertain aerodynamic coefficients, which are in turn used in the MRAC to enable an aircraft to track reference trajectories. The performance of the adaptive parameter estimator is compared to that of the Extended Kalman Filter (EKF), a …
Investigation Of Trajectory And Control Designs For A Solar Sail To The Moon,
2021
Embry-Riddle Aeronautical University
Investigation Of Trajectory And Control Designs For A Solar Sail To The Moon, Michelle Nadeau
Doctoral Dissertations and Master's Theses
NASA’s Artemis program and other government and commercial projects are working toward establishing a sustainable human presence on the moon. This thesis investigates the technical feasibility of a solar sail-based spacecraft (sailcraft) as a low-cost method of delivering cargo or science instruments to the moon and demonstrates how this sailcraft could be controlled to change its orbit. The concept is a low-cost, commercial launch vehicle-deployable, CubeSat-based sailcraft with a square sail, assumed attitude control, and a small payload traversing from low-Earth orbit toward the moon with zero propellant use. In this thesis, methods for sailcraft to increase altitude, the trajectory …
Ion Gnss Software-Defined Radio Metadata Standard,
2021
Air Force Institute of Technology
Ion Gnss Software-Defined Radio Metadata Standard, Sanjeev Gunawardena, Thomas Pany, James Curran
Faculty Publications
The past several years have seen a proliferation of software‐defined radio (SDR) data collection systems and processing platforms designed for or applicable to satellite navigation (satnav) applications. These systems necessarily produce datasets in a wide range of different formats. To correctly interpret this SDR data, essential information such as the packed sample format and sampling rate is needed. Communicating this metadata between creators and users has historically been an ad‐hoc, cumbersome, and error‐prone process. To address this issue, the satnav SDR community developed a metadata standard and normative software library to automate this process, thus simplifying the exchange of datasets …
Improved Strain Gage Instrumentation Strategies For Rotorcraft Blade Measurements,
2021
Old Dominion University
Improved Strain Gage Instrumentation Strategies For Rotorcraft Blade Measurements, Timothy S. Davis
Mechanical & Aerospace Engineering Theses & Dissertations
In this work, a new strategy is presented to wire, calibrate, and measure strain gages for rotor blade testing that will provide more information and is robust to individual gage loss. The additional information can be used in several ways. including reducing redundancy, offering rapid identification of damage locations, and in some cases reducing risk allowing tests to continue to collect calibrated data after one or more sensors have failed. This strategy replaces the classical four-gage full Wheatstone bridge with four separately wired quarter bridges that are combined into a full bridge in the data acquisition system using a calculated …
A New Method For Estimating The Physical Characteristics Of Martian Dust Devils,
2021
Old Dominion University
A New Method For Estimating The Physical Characteristics Of Martian Dust Devils, Shelly Cahoon Mann
Mechanical & Aerospace Engineering Theses & Dissertations
Critical to the future exploration of Mars is having a detailed understanding of the atmospheric environment and its potential dangers. The dust devil is one of these potential dangers. The transport of dust through saltation is believed to be the driving mechanism responsible for Martian weather patterns. The two primary mechanisms for dust transport are dust storms and dust devils. Dust devils on Mars are a frequent occurrence with one in five so called giant dust devils being large enough to leave scars on the surface that are visible from space. Due to the thin atmosphere, winds of 60 mph …
The Impact Of Uas On The Passenger Airline Industry,
2021
Liberty University
The Impact Of Uas On The Passenger Airline Industry, Matthew Whitten
Senior Honors Theses
This study seeks to cover the state of modern autonomous unmanned aerial systems (UAS) integration into commercial aviation, the future applications of the technology in the airline industry, and the roadblocks currently hindering its integration into passenger operations. Although great advancements are being made in the field, technological developments, economic impact, legal restrictions, airline cost, and public perception stand in the way of the full adaptation of autonomous technology into everyday passenger operations. However, technology is rapidly developing, perhaps allowing for the possibility of autonomous air travel even today, but there are likely years of refinement before regulators, executives, and …
A Comparative Study Between 6 Degree-Of-Freedom Trajectory Model And Modified Point Mass Trajectory Model Of Spinning Projectiles,
2021
Embry-Riddle Aeronautical University
A Comparative Study Between 6 Degree-Of-Freedom Trajectory Model And Modified Point Mass Trajectory Model Of Spinning Projectiles, Ange Du
Doctoral Dissertations and Master's Theses
For spinning projectiles, the 6 Degree-of-Freedom model can closely capture their trajectories with high accuracy and details. However, it comes with the drawbacks of long computation time and needing many aerodynamic coefficients which can be hard to obtain. The Modified Point Mass Trajectory Model was introduced as a simplified solution. This work compares them with each other, and with some more conventional methods. A program is developed to simulate and visualize trajectories. With some augmentations, the Modified Point Mass model is able to generate comparable results in most cases, but not including special cases such as when the projectile is …
Failure Of Ultra-High Molecular Weight Polyethylene Yarns (Uhmpwe) Under Transverse Loading Using Different Indenter Geometries,
2021
University of South Carolina
Failure Of Ultra-High Molecular Weight Polyethylene Yarns (Uhmpwe) Under Transverse Loading Using Different Indenter Geometries, Karan Shah
Theses and Dissertations
Ultra-high molecular weight polyethylene (UHMWPE) Dyneema® SK-76 fibers are widely used in personnel protection systems. Transverse ballistic impact onto these fibers results in complex multiaxial deformation modes such as axial tension, axial compression, transverse compression, and transverse shear. Previous impact studies on high performance yarns and quasi-static transverse loading of single fibers using different indenter geometries show premature failure of yarns and single fiber caused by the degradation of tensile failure strain due to the presence of such multi-axial deformation modes. However, there is a dearth of failure criterion in the literature for ballistic applications that considers the contribution of …
A Model-Based Systems Engineering Approach To E-Vtol Aircraft And Airspace Infrastructure Design For Urban Air Mobility,
2021
Old Dominion University
A Model-Based Systems Engineering Approach To E-Vtol Aircraft And Airspace Infrastructure Design For Urban Air Mobility, Heidi Selina Glaudel
Mechanical & Aerospace Engineering Theses & Dissertations
This paper serves to contribute to Model-Based Systems Engineering (MBSE) by following the NASA Systems Engineering Handbook framework for a Systems Engineering (SE) design approach to an Electric Vertical Takeoff and Landing (e-VTOL) aircraft and the incorporating airspace infrastructure. The focus of this study is, by using the MBSE model created, to capture the technical requirements definition and design intent of the vehicle and airspace inclusive of community specific knowledge derived from the Federal Aviation Administration (FAA) NextGen Urban Air Mobility (UAM) Concept of Operations (ConOps) version 1.0. The stakeholder requirements derived from the FAA UAM NextGen ConOps will form …
Wind Tunnel Wake Generator,
2021
Air Force Institute of Technology
Wind Tunnel Wake Generator, Carl Pickl, James L. Rutledge, Marc D. Polanka, Brian Crabtree, Christopher Harkless
AFIT Patents
A wake generator for placement in a wind tunnel between a wind source and a test object for generating a predetermined wake pattern, comprising: a first frame member comprising a first track formed thereon, the first track having a rounded first side and a flat second side; a mounting plate disposed within a perimeter of the first track, the mounting plate rotatable relative to the first frame member about a first axis; and a plurality of bars slidably engaged to the mounting plate and structurally configured to traverse along the first track when the mounting plate is rotated about the …
Sharing Airspace: Simulation Of Commercial Space Horizontal Launch Impacts On Airlines And Finding Solutions,
2021
Embry Riddle Aeronautical University
Sharing Airspace: Simulation Of Commercial Space Horizontal Launch Impacts On Airlines And Finding Solutions, Janet K. Tinoco, Chunyan Yu, Rodrigo Firmo, Carlos Alberto Castro, Mohammad Moallemi, Ryan Babb
Publications
Commercial space transportation is becoming more affordable and accessible. Consequently, we expect to see significant expansion of commercial space launch activities in the coming decade. As space vehicles travel through airspace during the launch and re-entry stages, they potentially disrupt the regular operations of traditional users. This paper estimates the potential economic and operational impacts of commercial space horizontal launch activities on airlines under various launch scenarios using predictive fast-time simulation modeling, focusing on Cecil Air and Space Port in Jacksonville (Florida) and the rules governing the national airspace system (NAS) in the United States. Our results indicate that the …
Time-Dependent System Reliability Analysis With Second-Order Reliability Method,
2021
Missouri University of Science and Technology
Time-Dependent System Reliability Analysis With Second-Order Reliability Method, Hao Wu, Zhangli Hu, Xiaoping Du
Mechanical and Aerospace Engineering Faculty Research & Creative Works
System reliability is quantified by the probability that a system performs its intended function in a period of time without failures. System reliability can be predicted if all the limit-state functions of the components of the system are available, and such a prediction is usually time consuming. This work develops a time-dependent system reliability method that is extended from the component time-dependent reliability method using the envelope method and second-order reliability method. The proposed method is efficient and is intended for series systems with limit-state functions whose input variables include random variables and time. The component reliability is estimated by …
Comparing Radiation Shielding Potential Of Liquid Propellants To Water For Application In Space,
2021
California Polytechnic State University, San Luis Obispo
Comparing Radiation Shielding Potential Of Liquid Propellants To Water For Application In Space, John Czaplewski
Master's Theses
The radiation environment in space is a threat that engineers and astronauts need to mitigate as exploration into the solar system expands. Passive shielding involves placing as much material between critical components and the radiation environment as possible. However, with mass and size budgets, it is important to select efficient materials to provide shielding. Currently, NASA and other space agencies plan on using water as a shield against radiation since it is already necessary for human missions. Water has been tested thoroughly and has been proven to be effective. Liquid propellants are needed for every mission and also share similar …
Data-Driven Cfd Scaling Of Bioinspired Mars Flight Vehicles For Hover,
2021
University of Alabama in Huntsville
Data-Driven Cfd Scaling Of Bioinspired Mars Flight Vehicles For Hover, Jeremy A. Pohly, Chang-Kwon Kang, Brian D. Landrum, James E. Bluman, Hikaru Aono
PRC-Affiliated Research
One way to improve our model of Mars is through aerial sampling and surveillance, which could provide information to augment the observations made by ground-based exploration and satellite imagery. Flight in the challenging ultra-low-density Martian environment can be achieved with properly scaled bioinspired flapping wing vehicle configurations that utilize the same high lift producing mechanisms that are employed by insects on Earth. Through dynamic scaling of wings and kinematics, we investigate the ability to generate solutions for a broad range of flapping wing flight vehicles with masses ranging from insects O(10−3) kg to the Mars helicopter Ingenuity O(100) kg. A …
Data-Driven Cfd Scaling Of Bioinspired Mars Flight Vehicles For Hover,
2021
University of Alabama in Huntsville
Data-Driven Cfd Scaling Of Bioinspired Mars Flight Vehicles For Hover, Jeremy A. Pohly, Chang-Kwon Kang, Brian D. Landrum, James E. Bluman, Hikaru Aono
PRC-Affiliated Research
One way to improve our model of Mars is through aerial sampling and surveillance, which could provide information to augment the observations made by ground-based exploration and satellite imagery. Flight in the challenging ultra-low-density Martian environment can be achieved with properly scaled bioinspired flapping wing vehicle configurations that utilize the same high lift producing mechanisms that are employed by insects on Earth. Through dynamic scaling of wings and kinematics, we investigate the ability to generate solutions for a broad range of flapping wing flight vehicles with masses ranging from insects O(10−3) kg to the Mars helicopter Ingenuity O(100) kg. A …
Accelerated Controller Tuning For Wind Turbines Under Multiple Hazards,
2021
Louisiana State University
Accelerated Controller Tuning For Wind Turbines Under Multiple Hazards, Aly Mousaad Aly, Milad Rezaee
Faculty Publications
During their lifecycle, wind turbines can be subjected to multiple hazard loads, such as high-intensity wind, earthquake, wave, and mechanical unbalance. Excessive vibrations, due to these loads, can have detrimental effects on energy production, structural lifecycle, and the initial cost of wind turbines. Vibration control by various means, such as passive, active, and semi-active control systems provide crucial solutions to these issues. We developed a novel control theory that enables semi-active controller tuning under the complex structural behavior and inherent system nonlinearity. The proposed theory enables the evaluation of semi-active controllers’ performance of multi-degrees-of-freedom systems, without the need for time-consuming …
The Effects Of Remotely Piloted Aircraft Command And Control Latency During Within-Visual-Range Air-To-Air Combat,
2021
Embry-Riddle Aeronautical University
The Effects Of Remotely Piloted Aircraft Command And Control Latency During Within-Visual-Range Air-To-Air Combat, David Thirtyacre
Doctoral Dissertations and Master's Theses
The type of military missions conducted by remotely piloted aircraft continues to expand into all facets of operations including air-to-air combat. While future within-visual-range air-to-air combat will be piloted by artificial intelligence, remotely piloted aircraft will likely first see combat. The purpose of this study was to quantify the effect of latency on one-versus-one, within-visual-range air-to-air combat success during both high-speed and low-speed engagements. The research employed a repeated-measures experimental design to test the various hypothesis associated with command and control latency. Participants experienced in air-to-air combat were subjected to various latency inputs during one-versus-one simulated combat using a virtual-reality …
A Method For Visualizing The Structural Complexity Of Organizational Architectures,
2021
California Polytechnic State University, San Luis Obispo
A Method For Visualizing The Structural Complexity Of Organizational Architectures, Jacob Michael B. King
Master's Theses
To achieve a high level of performance and efficiency, contemporary aerospace systems must become increasingly complex. While complexity management traditionally focuses on a product’s components and their interconnectedness, organizational representation in complexity analysis is just as essential. This thesis addresses this organizational aspect of complexity through an Organizational Complexity Metric (OCM) to aid complexity management. The OCM augments Sinha’s structural complexity metric for product architectures into a metric that can be applied to organizations. Utilizing nested numerical design structure matrices (DSMs), a compact visual representation of organizational complexity was developed. Within the nested numerical DSM are existing organizational datasets used …
A Reference Architecture For Rapid Cubesat Development,
2021
Air Force Institute of Technology
A Reference Architecture For Rapid Cubesat Development, Sean R. Kelly
Theses and Dissertations
The CubeSat class of nanosatellites has lowered the barrier of entry to space and has rapidly gained popularity in recent years. To successfully design a CubeSat system in a rapid cycle conducive to academic timelines, a Reference Architecture geared towards University CubeSat development would be helpful. A Reference Architecture would speed up the development process by providing a template, capturing previous work and lessons learned from subject matter experts, providing a framework to focus on the CubeSats design rather than the fine details of modeling software. A Reference Architecture can also add functionality that student teams could use and improve …
Comparison Of Decision Analysis Methods For A Cubesat Propulsion System,
2021
Air Force Institute of Technology
Comparison Of Decision Analysis Methods For A Cubesat Propulsion System, Jared L. Pilcher
Theses and Dissertations
Low Earth Orbit (LEO) is becoming an increasingly congested orbital regime. As a result, propulsion systems on CubeSats are becoming a more desirable feature to provide them with collision avoidance capabilities. To date, there have been very few CubeSat launches with a propulsion system on them. Due to the relatively high cost of a propulsion system compared to the budget of small educational organizations, a decision analysis model is needed so that these organizations can make the best decision between whether to purchase a Commercial-Off-The-Shelf (COTS) product or to develop one within the organization. This research applies three decision analysis …
