Mechanical Engineering Commons^™

Machine Vision For In Situ Measurement And Control Of Wire Stickout In Lwded Process, Braden Mclain, Remy Mathenia, Todd Sparks, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This work presents a machine-vision–based measurement and control framework for laser wire directed energy deposition (LWDED) processes. A visible-light camera system is used to capture meltpool images, from which a novel vision algorithm extracts the wire–meltpool interface location. By utilizing a camera that is rigidly mounted to the deposition head, the vision algorithm provides a relative measurement of the distance between the nozzle tip and the workpiece, also referred to as wire stickout. A proportional-derivative (PD) control strategy is implemented using the measured stickout as feedback to adjust deposition feedrate. Results show that the control system successfully compensates for improper …

Using Machine-Learning-Based Process Map To Guide Evaluation Of Inconel 625 Mechanical Properties In Laser Foil Printing, Yu Hsiang Wang, Sung Heng Wu, Hung Chu Chiang, Pen Ning Yu, Chia Hung Hung, Ming C. Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Inconel 625 is widely studied in powder-based additive manufacturing, but its processing characteristics and mechanical performance in foil-feedstock laser foil printing (LFP) remain largely unexplored. In this study, a gradient boosting regression (GBR)-based process map was developed for LFP of Inconel 625 using 32 single-track experiments. The GBR model achieved R² values of 0.859 and 0.793 and mean absolute errors of 22.25 μm and 19.83 μm for melt-pool depth and width, respectively, outperforming second- and third-order polynomial regressions in capturing nonlinear melt-pool responses and distinguishing lack-of-fusion, conduction, and keyhole regimes. Three conduction-mode conditions with target depth-to-foil thickness ratios (D/T) …

Electric Charging Arm Mechanism - Echarm, Jacob A. Lewis, Gabriel A. Greer

Mechanical Engineering Student Research

As demand for electric and hybrid vehicles continues to rise, many EV owners rely on home charging in their garages. Gabriel Greer and I’s Senior Design Project, the Electric Charging Arm Mechanism (ECHARM), addresses this by creating a robotic system that autonomously detects a vehicle’s charging port, connects to it, and returns to a rest position when charging is complete. ECHARM is designed as a six-axis robotic arm with wrist and shoulder joints driven by stepper motors through custom cycloidal drive gearboxes. A closed-loop control system using rotary potentiometers ensures precise motion control. At the end of the arm is …

Enhancing The Leaning Control And Braking Sensation Of A Virtual Reality Vespa Simulator, Joseph Boccuzzi, Wesley Bleck, Jacob Hannebaum

Honors Capstones

The 71 North Partnership Studio located in Northern Illinois University’s Founders Memorial Library has developed a prototype Vespa simulator featuring an interactive Virtual Reality (VR) game and reactive elements. A previous Mechanical Engineering Senior Design team developed the system and improvements after its original development were sought after over the course of the current school year. The system consists of a stationary bike that allows the rider to lean left and right, which in turn causes their in-game character to turn left and right accordingly, simulating the effect of riding a Vespa scooter within a VR environment. Improvements were made …

Optimization Of Stamped Tool Geometry Using Regression-Based Cost Models And Structural Constraints, Matthew J. Teague

Mechanical Engineering Undergraduate Honors Theses

Stamped steel paint can openers are simple tools but still require sufficient strength for the end user and low material consumption for the manufacturer. The goal of this project is to optimize the stamped design of a paint can opener by reducing material cost while maintaining structural rigidity and device performance. This was achieved in part by simplifying the tool’s geometry so that an equation for the mass could be developed analytically and checked against the simulation’s outputs. First, a 25-run design of experiments was created that varied the shaft length and the endloop diameter. Next, a CAD model for …

A Multi-Criteria Decision And Spatial Modeling Framework For Socially Informed Advanced Air Mobility Implementation Planning, Noah Wesley Bretz

Graduate Theses and Dissertations

Advanced air mobility (AAM) is an emerging mode of transportation that integrates advanced aircraft technologies, such as manned air taxis or unmanned freight drones, to transport people and goods across urban and regional environments. While these technologies promise to transform mobility, successful implementation depends heavily on community acceptance, which is shaped by multiple social factors. This study presents a multi-criteria decision framework to evaluate and prioritize the key social factors influencing AAM adoption. A literature review identified six primary social factors: safety, noise, privacy and cybersecurity, automation, environmental impact, and price and economics. The Analytical Hierarchy Process (AHP) was used …

Versatile Exoskeleton Control Paradigms For Agile Human Locomotion: Task-Agnostic And Stability-Augmented Assistance, Miao Yu

All Dissertations

Lower-limb exoskeletons have shown great potential for assisting human locomotion, but designing controllers that provide assistance across diverse locomotor tasks and under external perturbations remains a major challenge. Many existing controllers for steady-state walking rely on pre-defined reference trajectories, which constrain voluntary human motion and limit adaptability across tasks. Moreover, they usually assume stable walking, while their performance under unstable conditions remains largely unexplored. In addition, existing gait stability augmentation controllers are often reactive rather than proactive to unstable conditions. In this dissertation, we propose control frameworks that preserve voluntary human motion while addressing two major challenges: providing task-agnostic assistance …

Moon Adaptive Technology For Extraterrestrial Architectural Robotics (Matear), Candela Noemi Solis Zampini

Theses and Dissertations

The Moon Adaptive Technology for Extraterrestrial Architectural Robotics (MATEAR) focuses on the development of an autonomous robotic system capable of providing structural building blocks directly from lunar regolith. As a sustained human presence on the Moon becomes a necessity, the costly and limited payload capacity associated with transporting construction goods from Earth creates a critical challenge. MATEAR addresses this problem through in-situ resource utilization (ISRU), integrating a regolith processing system onto a remote operated vehicle. The proposed system is designed to collect lunar dust, mechanically compact the material, and apply thermal treatment to enhance cohesion through sintering. These regolith-made bricks …

Deep Learning For Predicting Impact Energy And Compression After Impact Strength Of Composite Materials Using C-Scan Images, K. T. Tan, Jason P. Mack, Faizan Mirza, Zhong-Hui Duan

University Research

Traditional assessment of post-impact performance in carbon fiber reinforced polymer (CFRP) composites often relies on simplified scalar metrics that fail to capture the complex spatial interactions driving failure. This study addresses this limitation by developing an automated, end-to-end deep learning framework that shifts from manual feature extraction to the direct interpretation of raw damage morphology from ultrasonic C-scans. Using a ResNet18-based convolutional neural network (CNN) trained on 1,428 augmented images, the model achieved coefficients of determination (R2) of 0.7948 ± 0.0847 for compression after impact (CAI) strength and 0.9436 ± 0.0098 for impact energy. Beyond prediction, this dual-purpose methodology serves …

Stakeholder Perspective-Taking In Engineering Design: A Neurocognitive Approach, Megan C. Taylor

Mechanical Engineering Undergraduate Honors Theses

Stakeholder engagement is a critically important yet overlooked phase of engineering design. While addressing stakeholders is known to lead to more thoughtful design outcomes, little work has been done regarding how stakeholder personas influence brain activity while designing. This study asks if the introduction of stakeholder personas- short overviews of people affected by a design problem- affects brain activation in undergraduate students during three design tasks: stakeholder identification, stakeholder needs generation, and stakeholder needs prioritization. To test this, 18 undergraduate mechanical engineering students were given a stormwater management design vignette; one group was given four stakeholder personas, while the control …

Tribological Evaluation Of A Graphite Coating Using A Custom Miniature Conveyor, Shae Threlfall

Mechanical Engineering Undergraduate Honors Theses

Reducing friction in conveyor systems has significant economic and environmental implications, as a substantial portion of energy losses originates at the belt-bed interface. This thesis outlines the design, construction, and validation of a miniature conveyor tribological test system. Unlike conventional tribometers, which impose concentrated point contacts, the miniature conveyor replicates the distributed load consistent with industrial conveyor systems. It can measure real-time mechanical responses of steel samples coated in a low friction coating.

The mini conveyor was validated by evaluating three materials: uncoated mild steel, PDA/graphite coated steel, and Polytetrafluoroethylene (PTFE). Electrical power, temperature, sound, and acceleration were recorded. Electrical …

Effect Of Prefilmer Design On Atomization Behavior In The Pre-Vaporization Tube Of A Small-Scale Annular Gas Turbine Combustior, Amogh G. Natu, Antoine M. Fradet, Cohen Nunes, Daniel R. Guildenbecher

School of Mechanical Engineering Faculty Publications

This work investigates the influence of internal prefilmer geometry on fuel spray atomization in the prevaporization tube (PVT) of a small-scale reverse-flow annular gas turbine combustor. Four configurations are examined: a control with no prefilmer, a planar internal prefilmer, and two angled internal prefilmers at θ = 60◦ and θ = 45◦ . Double-pulsed digital in-line holography (DIH) is used to measure droplet size distributions, spray density, Sauter mean diameter (SMD), and droplet velocities at the PVT exit under conditions scaled to represent nominal ignition conditions. Results show the control design exhibits poor atomization characterized by large droplet diameters, low …

Automating Building Feature Recognition In Digital Twin Models Using Computer Vision, Jaron Harbison

Undergraduate Honors Capstone Projects

Standard 3D scans treat all surfaces as generic geometry, but Wi-Fi signals don't. A signal drops by a different magnitude through a wooden door than a concrete wall. Without labeling these materials, Internet Service Providers (ISPs) cannot accurately predict "dead zones". This project addresses that gap by creating a machine learning model that identifies structural and architectural features. This includes features such as walls, doors, windows, and columns directly from RGB-D (Red, Green, Blue, Depth) point cloud data. 

I constructed the model on a custom U-Net architecture featuring a symmetric encoder-decoder structure with skip connections, trained on the StructScan3D dataset …

Tau Beta Pi Engineering Mentorship Program, Tyler Black

Undergraduate Honors Capstone Projects

The purpose of this project is to design and implement a student-led engineering mentorship program directed by the members of the Utah Gamma Chapter of Tau Beta Pi on the Utah State University (USU) Logan campus. Retention data show that many undergraduate students who start engineering programs change their degree before graduation due to academic and social challenges that may be mitigated by the support of a peer mentor. The Tau Beta Pi Engineering Mentorship Program selects and trains upperclassman mentors to effectively mentor underclassman engineering students.

The design of the mentorship program is an application of backward design, where …

Exercise-Induced Muscle Damage As A Model For Exploring The Effects Of Pain On Gait, Sydney Savage

All Theses

Persistent gait asymmetry following anterior cruciate ligament reconstruction (ACLR) is a recognized contributor to post-traumatic knee osteoarthritis, yet the independent role of pain in driving altered movement patterns remains poorly understood due to confounding factors inherent to clinical populations. This study used exercise-induced muscle damage (EIMD) as a controlled experimental model to isolate the effects of musculoskeletal pain on gait, independent of kinesiophobia, structural damage, and proprioceptive disruption. Eighteen healthy adults underwent unilateral eccentric calf-raise protocols to induce delayed onset muscle soreness (DOMS), with gait assessed at baseline, 48 hours, and 168 hours post-exercise using bilateral inertial measurement units. Outcomes …

Development Of Low-Cost Triaxial Force Sensor For Measurement Of Human-Exoskeleton Interaction Forces, Hamdan Khan Sarvathullah

All Theses

Contemporary research suggests that shear force is a major contributor to discomfort and pressure injury. However, the variation of shear forces during human-exoskeleton interaction dynamics is a highly unexplored field. The high cost of commercial triaxial force sensors may be a major factor in the notable lack of research in this field. Therefore, in this paper, we present a low-cost, 3D-printed triaxial force sensor designed specifically to measure the triaxial interaction forces between an exoskeleton and its user. The triaxial force sensor uses Carbon-Black/Silicone Rubber (CB/SR) strings to measure shear forces, whereas the normal force is measured with a Force …

Extremum Seeking Compensation And Quantification Of Position Sensor Offset Error In Speed-Controlled Permanent Magnet Synchronous Motors, Tessa Biondo

Masters Theses

Position sensor offset errors present a persistent challenge in speed-controlled permanent magnet synchronous motor drives operating under field-oriented control. Even small, constant offsets in the measured rotor position can reduce torque effectiveness, requiring increased current and voltage demand to maintain the commanded speed and resulting in degraded speed regulation performance across a range of operating conditions. These effects are particularly problematic in speed-controlled systems, where speed loop dynamics cause increased electrical effort and limit overall performance. Many existing detection and compensation approaches are either dependent on the system model, require offline calibration, or are primarily designed for torque-controlled operation. This …

Safe Control Design For Quadruped Locomotion In Unstructured Environments Using Linear Transfer Operators, Sriram Sundar Krishnamoorthy Shankara Narayanan

All Dissertations

Deploying quadruped robots in unstructured, obstacle-rich environments requires control and planning methods that remain safe and reliable despite complex terrain geometry, limited sensing, and inevitable modeling errors. This thesis develops operator-theoretic tools for safe control design of robotic systems using linear transfer operators, with a focus on quadruped locomotion in unstructured environments. The central goal is to develop a unified operator-theoretic framework for safe control design based on the Perron–Frobenius (P–F) and Koopman operators. In particular, the thesis leverages \emph{density functions} to develop safe navigation frameworks in the dual space of densities. In the operator-theoretic perspective, the P–F operator governs …

Interplay Between Phase Instability And Deformation Mechanisms In Beta Titanium Alloys In Aggressive Environments, Benjamin Elbrecht

All Dissertations

Modern designs, such as commercial jet turbines, are reliant on the high temperature performance of their constituent materials. Improvements to the strength-at-temperature of materials are critical to the continued advancement of efficiency and payload capacity in these advanced applications. This dissertation presents studies that progress towards this goal through the construction of a new experimental setup for complex temperature and force profiles that also accurately captures deformation behavior through non-contact measurements. Using this setup, studies into two specialty titanium alloys were executed: discovering the microscopic mechanisms responsible for the macroscale behavior and testing in conditions closely replicating aircraft turbine operating …

Experimental And Computational Investigation Of The Effects Of Neck Musculature During Head Impacts In American Football, Anthony P. Marino

All Dissertations

Anthropometric test devices (ATDs) are human surrogate models used to represent the human body response in the context of compliance and safety testing. These devices are used in multiple industries, including automotive and aerospace, and have recently been incorporated into impact testing for the evaluation of helmet performance in American football. The Hybrid III 50^th percentile male ATD head and neck assembly is the most commonly used surrogate for these tests, although it was developed for automotive frontal crash scenarios that induce an inertial force on the body, leading to head and neck motion primarily in the sagittal plane. …

Modernizing Plastics And Composites Manufacturing Using Hybrid Modeling Techniques, Luke Shannon

All Dissertations

Plastics and composites manufacturing encompasses a broad family of processes, including injection molding, resin transfer molding, compression molding, and extrusion, that together account for the vast majority of polymer and composite component production worldwide. These processes are inherently challenging due to the multi-physics nature of polymer processing, the vast possible combinations of resins, reinforcements, and additives, and the strong dependence of final part properties on process history. Among these processes, injection molding is one of the most widely deployed, producing high-volume components across automotive, medical, consumer electronics, and packaging industries. However, accurately monitoring and predicting process behavior in injection molding …

Development Of A Mixing-Controlled Combustion Model For 0d Engine Modeling: Using High-Order Models To Guide The Formulation Of Reduced-Order Models, James Gohn

All Dissertations

Vehicles are becoming increasingly complex to comply with the increasingly stringent regulations placed on all market sectors while still maintaining performance requirements. This increased complexity leads to increases in the cost and time it takes to develop and produce these next generation vehicles. To meet demand therefore, it becomes necessary to evaluate numerous design iterations using computer models. There are multiple levels of models that may be necessary for different purposes or use cases. All levels of modeling for virtual prototyping, however, require a level of validation and predictive ability to be useful. To this end, the following thesis presents …

Ngc - Torch Test Ablation Stand Improvements And Upgrades, Sarah Nelson

Undergraduate Honors Capstone Projects

This capstone project is sponsored by Northrop Grumman (NGC). The goal of the project is to redesign an ablation torch testing system to improve usability, safety, and versatility. Northrop Grumman relies on their ablation torch testing system to conduct quantitative evaluations of materials and high stress and high temperature conditions. The system provides essential data that supports product development, safety validation, and compliance with performance standards. By improving usability, safety, and versatility, NGC will be able to streamline testing operations, increase accuracy of results, and reduce operator risk. The system must allow testing using both a bent and straight torch …

Decomposition And Spectral Characterization Of Unsteady Loads In Pulse-Jet Propulsion Testing, Cesar Benitez

Theses and Dissertations

Pulsed jet propulsion systems produce inherently unsteady forces whose time-resolved characterization is essential for performance assessment, yet the measured load signal conflates aerodynamic forcing with the dynamic response of the measurement balance itself. This thesis develops a load centered framework for the dynamic characterization of a pulsed jet system, treating the measured load fluctuation as the primary physical observable rather than attempting full true-thrust reconstruction. A single-degree-of-freedom balance model identified through ringdown testing provides the structural reference scale, yielding a natural frequency of 8.5 Hz and damping ratio of 18%. Power spectral density, phase-averaging, and synchronous–residual decomposition is applied uniformly …

Examining The Effects Of Lateral Loading On Railroad Tapered Roller Bearings, Abel David Sanchez Trinidad

Theses and Dissertations

The loading conditions experienced by freight railcar bearings vary as a function of vehicle operating conditions. Under static conditions, bearings are primarily subjected to radial loads transmitted through the wheelset. During operation, however, track irregularities, braking events, railcar load imbalances, and curving introduce complex impact, longitudinal, and lateral forces in addition to the normal radial loading. These lateral forces increase friction within the bearing raceways, which could accelerate wear and potentially lead to premature spall initiation and propagation. While prior research at the University Transportation Center for Railway Safety (UTCRS) has demonstrated that vibration signatures can be used to detect …

Manufacturing Systems: Characteristics And Dynamics, Alan J. Fitzmorris

Graduate Theses and Dissertations (2019 - present)

This research answers three basic questions. First, what are the behaviors (dynamics) of a manufacturing system in the context of system performance? Are these dynamics best described as linear deterministic, periodic, nonlinear deterministic, or stochastic? Second, what are the complexity (chaotic) characteristics of a manufacturing system, namely the maximal Lyapunov exponent, correlation dimension, and Kolmogorov-Sinai entropy? Third, is there a relationship between complexity characteristics and manufacturing system performance? This research involves four high level steps: data analysis, system dynamics analysis, system complexity analysis, and correlation analysis. The data analyzed consists of concrete plant and shipbuilding shop time series performance data. …

Aerodynamic Parameter Estimation For A Scaled F-16: A Simulation-Based Sensitivity Analysis, Kathle C. Tischner

All Graduate Theses and Dissertations, Fall 2023 to Present

The physical motion of an aircraft is determined by the resulting forces and moments acting on the aircraft. These forces and moments can be defined as a mathematical equation where the control deflections, rotation rates, and orientation of the aircraft are multiplied by individual constants and summed together to define the entire force or moment. This method results in a highly accurate model that defines the motion of the aircraft at low angles of attack and sideslip. Initial calculations of the aerodynamic model are created based on analytical estimations based on the physical properties of the aircraft. Additional refinement of …

Development Of A Novel Method For Simultaneously Testing Multiple Specimens To Evaluate Tension-Tension Fatigue Life, Mehedi Hasan Mahfuz

All Graduate Theses and Dissertations, Fall 2023 to Present

The aim of this study is to develop a novel method for rapidly evaluating the tension–tension fatigue life of metals. Fatigue failure, which occurs when materials gradually weaken and fracture under repeated loading, is a critical concern in designing safe and reliable structures such as airplanes, cars, and bridges. Traditional fatigue testing methods are slow, costly, and typically limited to one specimen at a time. To address this, a high-throughput testing method was developed that allows multiple small-scale specimens to be tested simultaneously while following international testing standards. Using stainless steel sub-sized specimens scaled at 1:5 relative to the ASTM …

Two Applications Of Lifting-Line Theory For The Design Of Efficient Aircraft, Amanda K. Olsen

All Graduate Theses and Dissertations, Fall 2023 to Present

Numerical lifting-line is a tool that can be used to evaluate the forces and moments of an aircraft wing. This method has limitations but it is beneficial in obtaining a large set of results with relatively little computational power. This research seeks to analyze two different flight scenarios through the use of two numerical lifting-line tools developed at the Utah State University AeroLab. The first scenario involves an aircraft in ground effect flight. When an aircraft flies close to the ground, a phenomenon called ground effect occurs where the lift is increased and the induced drag is decreased. Therefore, flying …

Developing And Improving Digital Image Correlation (Dic) Techniques For Challenging Environments, Prasenjit Dewanjee

All Graduate Theses and Dissertations, Fall 2023 to Present

Understanding how materials and parts deform during testing is crucial for creating safer and more reliable engineering systems. Engineers need to measure not only how much a part deforms, but also where deformation concentrates before any damage or failure happens. Digital image correlation (DIC) is a camera-based, non-contact measurement method that tracks surface motion and deformation across a whole area. It is particularly useful when traditional contact-based measurement techniques cannot withstand harsh conditions or capture enough detail. This dissertation develops optical methods to improve DIC in three challenging measurement situations. First, a shortwave ultraviolet lighting technique is developed to reduce …