Physics Commons^™

Low Cost Magnetometer Calibration And Distributed Simultaneous Multipoint Ionospheric Measurements From A Sounding Rocket Platform, Joshua W. Milford

Doctoral Dissertations and Master's Theses

Low-cost and low-size-weight-and-power (SWaP) magnetometers can provide greater accessibility for distributed simultaneous measurements in the ionosphere, either onboard sounding rockets or on CubeSats. The Space and Atmospheric Instrumentation Laboratory (SAIL) at Embry-Riddle Aeronautical University has launched a multitude of sounding rockets in recent history: one night-time mid-latitude rocket from Wallops Flight Facility in August 2022 and three mid-latitude rockets from White Sands Missile Range during the October 2023 annular solar eclipse. All rockets had a comprehensive suite of instruments for electrodynamics and neutral dynamics measurements. Among this suite was one science-grade three-axis fluxgate magnetometer (Billingsley TFM65VQS / TFM100G2) and up …

Vertical Take-Off And Landing Control Via Dual-Quaternions And Sliding Mode, Joshua Sonderegger

Doctoral Dissertations and Master's Theses

The landing and reusability of space vehicles is one of the driving forces into renewed interest in space utilization. For missions to planetary surfaces, this soft landing has been most commonly accomplished with parachutes. However, in spite of their simplicity, they are susceptible to parachute drift. This parachute drift makes it very difficult to predict where the vehicle will land, especially in a dense and windy atmosphere such as Earth. Instead, recent focus has been put into developing a powered landing through gimbaled thrust. This gimbaled thrust output is dependent on robust path planning and controls algorithms. Being able to …

Global Formulation And Control Of A Class Of Nonholonomic Systems, Muhammad Rehan

Doctoral Dissertations and Master's Theses

This thesis study motion of a class of non-holonomic systems using geometric mechanics, that provide us an efficient way to formulate and analyze the dynamics and their temporal evolution on the configuration manifold. The kinematics equations of the system, viewed as a rigid body, are constrained by the requirement that the system maintain contact with the surface. They describe the constrained translation of the point of contact on the surface. In this thesis, we have considered three different examples with nonholonomic constraint i-e knife edge or pizza cutter, a circular disk rolling without slipping, and rolling sphere. For each example, …

Variable Structure Feedback Control With Application To Spacecraft With Small Thrust Propulsion Systems, Samuel J. Kitchen-Mckinley

Doctoral Dissertations and Master's Theses

Small spacecrafts requiring small propulsion systems are becoming more popular for low Earth orbit. It is important for these research satellites to have accurate guidance and control systems. Small propulsion systems will also be beneficial for multiple small spacecrafts used future exploration expeditions beyond low Earth orbit. These small spacecrafts benefit from the simplicity of low thrust cold gas propulsion systems. Additionally, large spacecrafts using low thrust, high specific impulse propellants for main propulsion systems, such as ion engines, allow longer and more flexible missions, including Earth orbiting spacecraft and interplanetary spacecraft.

In order to extend the life of future …

Nonlinear Control Of A Thermoacoustic System With Multiple Heat Sources And Actuators, Mikael O. Molina Sandoval

Doctoral Dissertations and Master's Theses

Thermoacoustic instabilities can occur in thermal devices when unsteady heat release is coupled with pressure perturbations. This effect results in excitation of Eigen-acoustic modes of the system. These instabilities can lead to unpredictable behavior of the system. Gas-turbine combustion systems are especially prone to this phenomenon reducing their overall efficiency. Additionally, due to the nature of the combustion, the turbines end up releasing undesired amounts of harmful chemicals to the atmosphere, such as Nitrous Oxide (NOX).

A Rijke tube, representing a resonator with a mean flow and a concentrated heat source, is a convenient system to study the thermoacoustic phenomena. …

Investigation Of Mountain Waves In The Mesosphere Over The Andes Mountains, Jaime Aguilar Guerrero

Doctoral Dissertations and Master's Theses

An image processing algorithm has been developed to analyze data from a NIR All-Sky Imager of OH airglow emission (from about 87 km altitude), located in the Andes, with the purpose of investigating the atmospheric gravity waves generated when low level wind blows over the high mountains (referred to as Mountain Waves). These types of waves are a special case of atmospheric gravity waves, which carry significant momentum and exert strong forcing to the background upper atmosphere. The imager is located at the Andes Lidar Observatory (ALO) at Cerro Pachón, Chile (30°S, 71°W), which also houses a Na Doppler Lidar …

Robust And Adaptive Nonlinear Control Of Limit Cycle Oscillations In Uavs Using Synthetic Jet Actuators, Natalie Ramos Pedroza

Doctoral Dissertations and Master's Theses

Limit cycle oscillations (LCO), also known as utter, cause significant challenges in fight control of unmanned aerial vehicles (UAVs), and could potentially lead to structural damage and catastrophic failures. LCO can be described as vibrational motions in the pitching and plunging displacements of an aircraft wing. Even in low Reynolds number (low-Re) fight regimes, LCO can exceed the limiting boundary for safe UAV fight. Further, as practical considerations motivate the design of smaller, lighter weight UAVs, there is a growing need for UAV systems that do not require heavy mechanical actuators (e.g., ailerons). To address this, the use of synthetic …

Molecular Dynamics Model Of Carbon Nanotubes In Epon 862/Detda Polymer, Guttormur Arnar Ingvason

Doctoral Dissertations and Master's Theses

The aerospace industry is interested in increasing the strength while reducing the weight of carbon fiber composite materials. Adding single walled carbon nanotubes (SWCNT) to a polymer matrix can achieve that goal by improving delamination properties of the composite. Due to the complexity of polymer molecules and the curing process, few 3-D Molecular Dynamics simulations of a polymer-SWCNT composite have been run. Our model runs on the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), with a COMPASS (Condensed phase Optimized Molecular Potential for Atomistic Simulations Studies) potential to represent the interactions between the atoms of the polymer and the SWCNT. This …

Nonlinear Control For Dual Quaternion Systems, William D. Price

Doctoral Dissertations and Master's Theses

The motion of rigid bodies includes three degrees of freedom (DOF) for rotation, generally referred to as roll, pitch and yaw, and 3 DOF for translation, generally described as motion along the x, y and z axis, for a total of 6 DOF. Many complex mechanical systems exhibit this type of motion, with constraints, such as complex humanoid robotic systems, multiple ground vehicles, unmanned aerial vehicles (UAVs), multiple spacecraft vehicles, and even quantum mechanical systems. These motions historically have been analyzed independently, with separate control algorithms being developed for rotation and translation. The goal of this research is to study …

Robust Control Methods For Nonlinear Systems With Uncertain Dynamics And Unknown Control Direction, Chau T. Ton

Doctoral Dissertations and Master's Theses

Robust nonlinear control design strategies using sliding mode control (SMC) and integral SMC (ISMC) are developed, which are capable of achieving reliable and accurate tracking control for systems containing dynamic uncertainty, unmodeled disturbances, and actuator anomalies that result in an unknown and time-varying control direction. In order to ease readability of this dissertation, detailed explanations of the relevant mathematical tools is provided, including stability denitions, Lyapunov-based stability analysis methods, SMC and ISMC fundamentals, and other basic nonlinear control tools. The contributions of the dissertation are three novel control algorithms for three different classes of nonlinear systems: single-input multipleoutput (SIMO) systems, …

Nonlinear Observers For Human-In-The-Loop Control Systems, Samuel Kitchen Mckinley

Master's Theses - Daytona Beach

The development of models for a human-in-the-loop with hardware is an area of ongoing research. The ability to simulate a human-in-the-loop with hardware provides a platform for better understanding the dynamics of human and machine cognition. A human-in-the-loop model provides information that can be used to design more efficient human interfaces and smarter autonomous assistant controllers. This can make a complex task such as flying an aircraft safer and more accessible. This thesis explores different possibilities for human operator models to be modeled in the loop with a vehicle. A human is modeled as a linear state feedback controller in …

Investigation Of Magnetic Field Profile Effects In Hall Thrusters, Oren Kornberg

Master's Theses - Daytona Beach

The purpose of this study was to show the relationship of different magnetic field profiles to the acceleration region length of a Hall thruster. The general transport equations were simplified and solved using a one-dimensional analysis. Some of the model assumptions include quasineutrality, Maxwellian electrons, and negligible thruster wall effects. The solved equation kept magnetic field as an input to the model for the analysis. The magnetic field was altered by changing the shape through the thruster, while keeping the maximum point fixed, and by shifting the profile, while keeping the shape fixed. Results indicate a strong correlation between the …

Dynamics Of Nonlinear Diffusion Processes, Dustin A. Sipka

Master's Theses - Daytona Beach

The purpose of this thesis is to analyze nonlinear diffusion processes. In particular, some of the results arrived at by Newman and Sagan in their 1981 paper "Galactic Civilizations: Population Dynamics and Interstellar Diffusion," will be reproduced by different means. First, a thorough analysis of the linear diffusion equation will be performed in order to test a numerical algorithm that can solve the nonlinear diffusion equation and look at the processes of interest with sufficient accuracy. Once the algorithm is tested and shows good resolution it is used to solve the nonlinear equation. The post processing is then done to …