Engineering Commons^™

Cyber-Threat Detection Strategies Governed By An Observer And A Neural-Network For An Autonomous Electric Vehicle, Douglas Scruggs

All Theses

A pathway to prevalence for autonomous electrified transportation is reliant upon accurate and reliable information in the vehicle’s sensor data. This thesis provides insight as to the effective cyber-attack placements on an autonomous electric vehicle’s lateral stability control system (LSCS). Here, Data Integrity Attacks, Replay Attacks, and Denial-of-Service attacks are placed on the sensor data describing the vehicle’s actual yaw-rate and sideslip angle. In this study, there are three different forms of detection methods. These detection methods utilize a residual metric that incorporate sensor data, a state-space observer, and a Neural-Network. The vehicle at hand is a four-motor drive autonomous …

Safe Navigation Of Quadruped Robots Using Density Functions, Andrew Zheng

All Theses

Safe navigation of mission-critical systems is of utmost importance in many modern autonomous applications. Over the past decades, the approach to the problem has consisted of using probabilistic methods, such as sample-based planners, to generate feasible, safe solutions to the navigation problem. However, these methods use iterative safety checks to guarantee the safety of the system, which can become quite complex. The navigation problem can also be solved in feedback form using potential field methods. Navigation function, a class of potential field methods, is an analytical control design to give almost everywhere convergence properties, but under certain topological constraints and …

Generalizable Deep-Learning-Based Wireless Indoor Localization, Ali Owfi

All Theses

The growing interest in indoor localization has been driven by its wide range of applications in areas such as smart homes, industrial automation, and healthcare. With the increasing reliance on wireless devices for location-based services, accurate estimation of device positions within indoor environments has become crucial. Deep learning approaches have shown promise in leveraging wireless parameters like Channel State Information (CSI) and Received Signal Strength Indicator (RSSI) to achieve precise localization. However, despite their success in achieving high accuracy, these deep learning models suffer from limited generalizability, making them unsuitable for deployment in new or dynamic environments without retraining. To …

Virtual Prototyping Of Pebb Based Power Electronics System For Ground Vehicles, Yi Li

All Theses

Power electronics are heavily involved in power and energy systems in plenty of applications nowadays. The increase of demand brings more challenges into simulations for development. Considering the complexity of the systems and high frequency operational conditions, this paper presents comprehensive research on modeling, simulating, and validation on ground vehicle propulsion system applications.

To reduce the computational burden, the Power Electronics Building Blocks concept is utilized to simplify the structure of modeling under different conversion scenarios in ground vehicle systems. In addition, the Average and Switching versions models are included. To speedup the simulation, the engagement of advanced computing technique …

The Application Of Model Predictive Control On Paralleled Converters For Zero Sequence Current Suppression And Active Thermal Management, Justin Dobey

All Theses

In the field of power electronics, the control of rectifiers is a crucial area of study. Rectifiers are used to convert AC power into DC power, and are commonly used in a wide range of applications, including renewable energy systems, industrial automation, and consumer electronics. However, in medium and high-power systems when multiple rectifiers are connected in parallel to a DC bus, stability issues can arise, including voltage fluctuations, zero sequence circulating current, and thermal imbalance.

Achieving stable DC bus voltage is essential for maintaining the proper functioning of electronic devices, while suppressing zero sequence current is necessary for protecting …

Augmented Human Inspired Phase Variable Using A Canonical Dynamical System, Timothy Driscoll

All Theses

Accurately parameterizing human gait is highly important in the continued development of assistive robotics, including but not limited to lower limb prostheses and exoskeletons. Previous studies introduce the idea of time-invariant real-time gait parameterization via human-inspired phase variables. The phase represents the location or percent of the gait cycle the user has progressed through. This thesis proposes an alternative approach for determining the gait phase leveraging previous methods and a canonical dynamical system.

Human subject experiments demonstrate the ability to accurately produce a phase variable corresponding to the human gait progression for various walking configurations. Configurations include changes in incline …

A Study Of 5g Cellular Connectivity To Unmanned Aerial Vehicles, Jackson Murrin

All Theses

The market of unmanned aerial vehicles (UAVs) has seen significant growth in the past ten years on both the commercial and military sides. The applications for UAVs are endless and options by manufacturers allow users to modify their drones for their specific goals. This industry has opened up the excitement of piloting vehicles in the air, photography, videography, exploration of nature from a different point of view and many other hobbies assisted by the emergence of UAVs. The growth of this industry coincides with the roll out of new 5G cellular network technology. This upgrade in cellular network infrastructure allows …

Tunable Linewidth Chip-Level Lasers Using Hybrid Integration Methods, Charles Porter

All Theses

Photonic integrated circuits (PICs) have significant value in today’s world of research. They enable devices to experience large reductions in size, weight, operation power, and cost (SWAPc), making photonic technology more accessible than ever. The functionality of PICs is greatly enhanced due to the realization of both active and passive devices within a single device structure. This is made possible through hybrid integration, which utilizes various coupling methods to transfer light from an active chip to a passive chip. Hybrid integration technology tremendously expands the capabilities of PICs, leading to a plethora of applications. One significant application is that of …

Design And Fabrication Of An Optical Blade Tip Timing Sensor, Nick Tomlinson

All Theses

Electricity is a vital energy source that powers modern technology. Turbines are heavily relied on in the electric power industry for the conversion of natural energy sources into electricity. These turbines operate under harsh conditions which increase the likelihood of blade damage. Structural health monitoring of a turbine’s blades is important to detect problems before a blade experiences failure. The blade tip timing method can be used to monitor blade vibrations and determine if damage has occurred. An optical blade tip timing sensor is designed and fabricated to advance the field of sensing in the power industry.

Digital Twins And Artificial Intelligence For Applications In Electric Power Distribution Systems, Deborah George

All Theses

As modern electric power distribution systems (MEPDS) continue to grow in complexity, largely due to the ever-increasing penetration of Distributed Energy Resources (DERs), particularly solar photovoltaics (PVs) at the distribution level, there is a need to facilitate advanced operational and management tasks in the system driven by this complexity, especially in systems with high renewable penetration dependent on complex weather phenomena.

Digital twins (DTs), or virtual replicas of the system and its assets, enhanced with AI paradigms can add enormous value to tasks performed by regulators, distribution system operators and energy market analysts, thereby providing cognition to the system. DTs …

Considerations Of The Impacts And System-Level Mitigation Of Electric Vehicle Charging On The Integrated Resource Planning Process, Grant Wollam

All Theses

Electric vehicles (EV) are growing in popularity and therefore adoption rate. Best estimates predict a 6.2% EV adoption rate by 2035 in the southeastern United States. With this level of EV adoption, utility planners must begin to consider the impact that EVs will have on the power grid. This paper aims to help predict these EV impacts on the power grid. Specifically, an urban-commercial feeder is analyzed in detail to provide worst-case and most-likely results of varying levels of EV impact. Results show that a 26.2% peak increase is the most likely result for this feeder in 2035.

Mitigation techniques …

Analyzing The Influence Of Stale Data On Autonomous Intelligent Transportation Systems, August St. Louis

All Theses

Intelligent transportation has been at the forefront of recent technological advancement. Individuals have developed a number of algorithms intended to automate and improve essential intelligent transportation functions. New developments include the incorporation of vehicle platooning and path planning algorithms within a number of use cases. Data perturbation can affect both algorithms significantly. We define data perturbation as any natural or unnatural phenomenon that causes the data to be skewed in any way. Perturbations within either system can cause its respective algorithm to operate with stale or incorrect data. This can significantly affect performance. This paper conducts a fault injection campaign …

Procedural City Generation With Combined Architectures For Real-Time Visualization, Griffin Poyck

All Theses

The work and research of this paper sought to build upon traditional city generation and simulation in creating a tool that both realistically simulates cities and their prominent features and also creates aesthetic and artistically rich cities using assets that combine several contemporary or near contemporary architectural styles. The major city features simulated are the surrounding terrain, road networks, individual buildings, and building placement. The tools used to both create and integrate these features were created in Houdini with Unreal Engine 5 as the intended final destination. This research was influenced by the city, town, and road networking of Ghost …

Universal Short-Circuit And Open-Circuit Fault Detection For An Inverter, Buck Brown

All Theses

Short-circuit and open-circuit faults of an inverter’s power device often lead to catastrophic failure of the entire system if not detected and acted upon within a few microseconds, particularly for emerging wide bandgap (WGB) power semiconductors. While a significant amount of research has been done on the fast and accurate protection and detection of short-circuit faults, there has been less success corresponding to the research on open-circuit faults. Common downfalls include protection and detection that are too application-specific, take longer than a couple of microseconds, and are not cost-efficient. This study proposes a new open-circuit fault protection and detection system …

A Study Of A Monolithic Pulsed Fiber Laser With High-Peak And Average Power, Mark Mihalik

All Theses

Fiber lasers with high peak power, pulse energy and average power have numerous industrial applications. This project aimed to build a Master Oscillator Power Amplification fiber laser using commercial components and specialty fiber designed by Clemson University to exceed the power and energy targets of a previous Q-switched fiber laser design. The specialty fiber has a low numerical aperture of 0.028 and a unique geometric core design to minimize amplified spontaneous emission and reduce nonlinear effects in order to produce a high-peak power and high per pulse energy. The two stage, monolithic design targets 3.1 mJ per pulse, average power …

Assessing Hardware Security Threats Posed By Hardware Trojans In Power Electronics, Quinn Kinzie

All Theses

This study investigates the threat of hardware Trojans (HTs) in power electronics applications, a rising concern due to the growing demand for cost-effective embedded solutions in power systems. With the supply chain for electronic hardware devices expanding globally, particularly to low-cost foundries in foreign locations, there is an increasing risk of HT attacks. While there has been extensive research on HTs in computer applications, little consideration has been given to their threat in power electronics. This study demonstrates the effectiveness of a power electronics HT by implementing a novel HT design into a gate drive circuit. Additionally, the research proposes …

Optical Control System For Atmospheric Turbulence Mitigation, Martyn Lemon

All Theses

Propagation of laser light is distorted in the presence of atmospheric turbulence. This poses an issue for sensing, free-space optical communications, and transmission of power. With an ever-increasing demand for high-speed data communications, particularly between satellites, unmanned vehicles, and other systems that benefit from a point-to-point link, this issue is critical for the field. A variety of methods have been proposed to circumvent this issue. Some major categories include the manipulation of the light’s structure, an adaptive scheme at the optical receiver, scanning mirror systems, or a transmission of simultaneous signals with a goal to improve robustness.

There is an …

Synthesis And Characterization Of Vo2 Thin Films On Piezoelectric Substrates, Samee Azad

All Theses

Polycrystalline VO₂ thin films synthesized on two piezoelectric substrates (AT-cut quartz and GaN/AlGaN/GaN/Si) using low pressure direct oxidation technique have been characterized and compared to VO₂ grown on traditional non-piezoelectric substrates sapphire and SiO₂/Si. X-ray diffraction and atomic force microscopy characterization performed on the as grown films confirmed high quality of the VO₂ films grown on both the piezoelectric and non-piezoelectric substrates. Changes in material properties associated with the semiconductor metal transition (SMT) of the VO₂ films were investigated through resistivity and transmitted optical power changes measured across the SMT. It was observed that …

Oam-Based Wavelets In A High Speed Optical Probing System For Measuring The Angular Decomposition Of The Environment, Justin Free

All Theses

This thesis presents the theoretical development of orbital angular momentum (OAM) based wavelets for the analysis of localized OAM information in space. An optical probing system for generating and detecting these wavelets is demonstrated; individual wavelets can scan the environment in 10µs or less. The probing system was applied to a three-dimensional atmospheric turbulence distribution to obtain a continuous wavelet transform of the angular information of the turbulent propagation path about a fixed radius. An entire continuous wavelet transform was measured in 3.8ms; the measurements are much faster than the turbulence and give insight into the short time scale of …

Design Of Arbitrary Planar Optical Devices With Full Phase Control Using Nanoimprinting Of Refractive Index, Matthew Panipinto

All Theses

Planar optical devices offer a lightweight solution to the constraints found in traditional optical devices. While subwavelength patterning of optics offers attractive performance and size, traditional fabrication methods demand a trade-off between resolution and throughput that presents a significant hurdle for the widespread use of subwavelength devices. Nanoimprinting of refractive index (NIRI) is a novel fabrication method pioneered in previous work that offers promise in mitigating the throughput issues that hamstring traditional fabrication methods. However, NIRI has not been shown to impart full $2\pi$ phase control in planar optical devices, nor has a method for fabricating arbitrary designs using the …

Digital And Gradient Refractive Index Planar Optics By Nanoimprinting Porous Silicon, Anna Hardison

All Theses

Due to the drawbacks of traditional refractive optics, the implementation of planar or nearly planar optical devices has been of research interest for over a century. Subwavelength gratings are a particularly promising option for creating flat optical devices; however, the implementation of subwavelength grating-based optics is limited by fabrication constraints. Recently, we implemented flat optical devices using the nanoimprinting of refractive index (NIRI) process, a process which was pioneered in a previous study but remained largely unproven in terms of device fabrication. The planar, gradient index microlenses we fabricated were found to possess an effective medium similar to a subwavelength …

Deep Learning Based Localization Of Zigbee Interference Sources Using Channel State Information, Dylan Kensler

All Theses

As the field of Internet of Things (IoT) continues to grow, a variety of wireless signals fill the ambient wireless environment. These signals are used for communication, however, recently wireless sensing has been studied, in which these signals can be used to gather information about the surrounding space. With the development of 802.11n, a newer standard of WiFi, more complex information is available about the environment a signal propagates through. This information called Channel State Information (CSI) can be used in wireless sensing. With the help of Deep Learning, this work attempts to generate a fingerprinting technique for localizing a …

Sub-Bandgap Photon-Assisted Electron Trapping And Detrapping In Algan/Gan Heterostructure Field-Effect Transistors, Andrew Gunn

All Theses

We have investigated photon-assisted trapping and detrapping of electrons injected from the gate under negative bias in a heterostructure field-effect transistor (HFET). The electron injection rate from the gate was found to be dramatically affected by sub-bandgap laser illumination. The trapped electrons reduced the two-dimensional electron gas (2DEG) density at the AlGaN/GaN heterointerface but could also be emitted from their trap states by sub-bandgap photons, leading to a recovery of 2DEG density. The trapping and detrapping dynamics were found to be strongly dependent on the wavelength and focal position of the laser, as well as the gate bias stress time …

Distributed Learning With Automated Stepsizes, Benjamin Liggett

All Theses

Stepsizes for optimization problems play a crucial role in algorithm convergence, where the stepsize must undergo tedious manual tuning to obtain near-optimal convergence. Recently, an adaptive method for automating stepsizes was proposed for centralized optimization. However, this method is not directly applicable to decentralized optimization because it allows for heterogeneous agent stepsizes. Furthermore, directly using consensus between agent stepsizes to mitigate stepsize heterogeneity can decrease performance and even lead to divergence.

This thesis proposes an algorithm to remedy the tedious manual tuning of stepsizes in decentralized optimization. Our proposed algorithm automates the stepsize and uses dynamic consensus between agents’ stepsizes …

Miniaturized Battery Powered Air Quality Monitoring System, Bryan Chacon

All Theses

In this work, an air quality monitoring system was developed using various sensors that measure specific air quality parameters, including Volatile Organic Compounds, Carbon Dioxide, particulate matter of varying sizes, ambient pressure, humidity, and temperature. This system is based off a Particle micro-controller, Boron LTE CAT-M1 which allows for cellular connectivity for real-time data transmission. It is powered by a 3.7 Volt Li-Po battery and has a miniaturized design which allows for portability. This data is processed through an Internet of Things software provider that allows for the device to be connected and accessed to and from anywhere in the …

An Evaluation Of Wi-Fi 802.11b Backscatter, Anthony Chen

All Theses

Internet of Things (IoT) devices are in need of low-power communications systems with longevity and reliability. With the use of backscatter technology, IoT devices can communicate at the cost of almost no power and can last for up to a decade. Furthermore, backscatter technology is compatible with everyday wireless signals such as Wi-Fi and Bluetooth, allowing for easy communication without specific hardware constraints. This thesis aims to evaluate a Wi-Fi backscatter system and analyze its ease in triggering off of such ambient signals and sources. The system will utilize Wi-Fi 802.11b as a backscatter source to trigger the backscatter system …

Addressing The Performance Of Distance Relays In Presence Of Inverter Based Resources, Prabin Adhikari

All Theses

The transition towards clean energy initiatives to reduce global greenhouse emissions and the dependence on fossil fuels requires the interconnection of large-scale renewable energy power plants to high voltage transmission networks via inverters. These inverter interfaced power sources, popularly known as inverter-based resources (IBRs), pose several technical challenges to the existing distance protection infrastructures widely deployed in transmission systems.

Fault characteristics of IBRs are significantly different from those shown by synchronous generators (SGs). With IBRs taking a large share of generation, their increasing penetration at the transmission level causes incorrect operation of existing distance protection schemes designed for systems dominated …

The Role Of Consumers In The Adoption Of Alternatively Fueled Vehicles And Mitigation Of Vulnerabilities Associated With Electric Vehicle Charging, Elaina D. Stuckey

All Theses

Electric vehicles have the potential to replace traditional automobiles as the primary form of transportation. Despite major improvements in technology and an expanding focus on climate change making electric vehicles more practical than ever before, consumers are still wary of adopting them for legitimate reasons such as costs and charging infrastructure. Therefore, a concerted effort must be made to persuade individuals and companies to adopt this beneficial technology to reduce the carbon footprint and catalyze the construction of important charging infrastructure.

Though there are a multitude of benefits to adopting electric vehicles, there will be some negative effects on the …

Soft Web-Based Continuum Robot Grippers, Anthony Carambia

All Theses

We discuss the potential of soft webs to enhance robotic grasping. Specifically, we explore a novel combination of compliant continuum digits interspersed with a flexible material. The resulting webbed structure offers the potential for new modes of robust and adaptive object grasping. We introduce and describe two webbed grippers featuring alternate modes of actuation: pneumatic muscles and remotely actuated tendons. Experiments with the grippers demonstrate their ability to gently capture small, fragile, and non-cooperative objects.

Improving Intelligent Transportation Safety And Reliability Through Lowering Costs, Integrating Machine Learning, And Studying Model Sensitivity, Cavender Holt

All Theses

As intelligent transportation becomes increasingly prevalent in the domain of transportation, it is essential to understand the safety, reliability, and performance of these systems. We investigate two primary areas in the problem domain. The first area concerns increasing the feasibility and reducing the cost of deploying pedestrian detection systems to intersections in order to increase safety. By allowing pedestrian detection to be placed in intersections, the data can be better utilized to create systems to prevent accidents from occurring. By employing a dynamic compression scheme for pedestrian detection, we show the reduction of network bandwidth improved by 2.12× over the …