Other Mechanical Engineering Commons^™

Implementation Of A Line-Scan Camera Triangulation Sensor For A Ball Balancer, Jackson R. Mclaughlin

Master's Theses

Ball Balancer or Ball on Plate systems are used for education and research in control theory. These consist of a plate which can be actively tilted, with a ball rolling on the surface. Students are challenged to model the dynamics of the system and implement a control loop which is capable of stabilizing the ball by actuating the plate.  The mechatronics group at Cal Poly is developing hardware for one of these ball-balancer systems, for future use in the Mechanical Engineering curriculum.

The position of the ball relative to the plate must be measured in order to control and stabilize …

Integration And Testing Of A Quadruped Robot With Ros2, Jeremy S. West

Master's Theses

The Cal Poly Legged Robotics Group has been developing research and teaching platforms for agile legged robotics since 2020. These platforms are expected to provide students with opportunities to develop complete legged-robot systems from low-level control to advanced robotics tasks such as motion planning and decision making. However, the current prototyped quadruped robot lacked the software and sensing capabilities for high-level quadrupedal gaits and advanced robotic research.

To address these challenges, this project developed Switch, a robotic platform that builds upon the previous BRUCE platform with significant hardware and software upgrades. Switch features a modular design that allows individual software …

Design Principles For Robotic-Controlled 3d Printing Of Soft Tissue-Mimicking Materials, Karina Mealey

Master's Theses

Geometrically and physically accurate 3D models are emerging as essential tools for surgeons in pre-operative planning and training, but current methods of producing these models are not sufficient. Existing solutions have downsides such as high costs, long and tedious production times, high complexity resulting in a lack of scalability, or an inability to meet material requirements for accurately simulating human tissue.

The objective of this work is to develop principles for a low-cost, easy-to-use 3D printing system capable of prototyping with soft tissue-mimicking materials. To pursue this goal, a MyCobot280 robot arm was used as the mechanism to explore the …

Design, Fabrication, And Testing Of A Dual-Rate Spring System For Mountain Bike Frames, Lucas P. Grizzle

Master's Theses

The design of full-suspension mountain bikes is a careful balance of suspension kinematics, structural dynamics, and manufacturing optimization for the expected use case. A bike designed to excel in one area will likely exhibit reduced performance in others. This optimization problem is addressed by designing, integrating, and testing a dual-rate spring system within a fully custom frame. The dual-rate spring is fully decoupled from the rest of the suspension kinematics, providing designers with an additional parameter to achieve ideal suspension behavior. This is accomplished by placing a thermoplastic polyurethane (TPU) bushing in series with the rear shock. The influence of …

Thermal Modeling Techniques For Additively Manufactured Porous Metals, Lucas D. Rambo

Master's Theses

Advances in additive manufacturing have enabled the creation of metallic components with tailored porosity, offering design flexibility for thermal, structural, and fluid transport applications. This thesis investigates the effective thermal conductivity (ETC) of porous Inconel 625 (IN625) and Inconel-ceramic composites (IN625-RAM2) fabricated by Laser Powder Bed Fusion (LPBF) using Elementum 3D’s PermiAM technology. Experimental measurements of thermal conductivity using the laser flash method are compared to numerical models built from micro-computed tomography data. Simulations were performed using both finite element (FE) and finite volume (FV) methods to evaluate thermal transport in real microstructures. The study investigates the effects of micro- …

Hands-Free Balance Protocol And Development Of An Iphone App For Self-Assessment, Jacob Matties

Master's Theses

For many clinical populations, the measurement of balance is a critical task. Previous studies have agreed that smartphone IMUs provide a valid measure of balance that can be significantly correlated with force plate measurements and is sensitive enough to distinguish between various balance poses, but many balance assessment protocols require uncommon equipment or the use of hands during assessment. These limit accessibility of balance assessment. To eliminate the need for hands or any additional equipment, this study assessed the use of a smartphone recording the root mean square of 3D acceleration magnitude. The goal of the study was to determine …

Modeling, Simulation, And Experimental Testing Of A Single-Legged Hopper, John Anthony Bennett

Master's Theses

Legged robots are well-suited for navigating unstructured terrain due to their ability to perform agile dynamic motions. Building on the efforts of Cal Poly's Legged Robotics Group, this project focuses on achieving stable forward hopping with a single legged robot.

A comprehensive model of leg hopping is formulated, with leg dynamics during flight and stance phases derived using Euler-Lagrange equations. During the stance phase, a spring-mass system models the leg-ground interaction. The touchdown and lift-off conditions are formulated mathematically, and state mappings between phases are determined via momentum conservation. A two-phase hybrid controller is designed, incorporating trajectory planning during flight …

Product Design For Repairability: Identifying Failure Modes With Topic Modeling And Designing For Electronic Waste Reuse, Claire J. Franz

Master's Theses

Design for repairability is imperative to making products that last long enough to justify the resources they consume and the pollution they generate. While design for repairability has been gaining steady momentum, especially with recent advances in Right to Repair legislation, there is still work to be done. There are gaps in both the tools available for repair-conscious designers and the products coming onto store shelves. This thesis work aims to help set sails in the right direction on both fronts.

This research explores the use of topic modeling (a natural language processing technique) to extract repairability design insights from …

Development Of Mirror Flexures For Use In The Muvi Instrument, Colin W. Harrop

Master's Theses

The Miniaturized Ultraviolet Imager (MUVI), is a compact wide field UV imaging instrument in development at UC Berkeley Space Sciences Laboratory and Cal Poly, San Luis Obispo. MUVI is designed to fit in a 2U CubeSat form factor and provide wide field, high resolution images of the ionosphere at far ultraviolet wavelengths. This thesis details the design and analyses of MUVI’s deployable cover mirror mounting flexures. Three different flexure geometries were evaluated, an optimal candidate was determined based on a number of criteria including isolation of vibration and stress to the mirrors, manufacturability and cost. The design of the flexure …

Development Of A Body Weight Reduction Algorithm In Micro-Gravity Treadmills™, Alexander Hibbert

Master's Theses

Boost Treadmills™, a company specializing in the use of differential air-pressure (DAP) technology in the realm of exercise and rehabilitation, is developing their second-generation micro-gravity treadmill™ named the Boost 2. This machine will allow individuals in all types of fitness environments to move and exercise at a fraction of their normal body weight, reducing the impact forces on lower body extremities and allowing for accelerated returns to activity.

The purpose of this thesis was to create an algorithm to be implemented on the Boost 2 that related the percentage of body weight reduction of a user to a required pressure …

Effect Of Indentation On Sandwich Composite Structure Mechanical Behavior, Marius V. Jatulis

Master's Theses

Composite sandwich structures are prevalent in engineering applications where high strength to weight ratios are critical. A composite sandwich includes the addition of a core material between two composite face sheets to increase ultimate stress in compression and bending loading cases. The performance of many composite sandwich structure configurations is well understood in the undamaged case. This analysis examines a type of damage, low velocity indentation, and determines the effect on mechanical behavior. The scope of the analysis includes manufacturing sandwich composite structures, creating indentation in the composite, and testing the sandwich composite structure. The mechanical behavior of the composite …

Testing And Characterization Of Polymer Laminates For Swelling, Absorption, And Cracking, Matthew W. Carlson

Master's Theses

A polymer laminate consisting of multiple layers of proprietary blends of Ethylene Vinyl Alcohol (EVOH) and Thermoplastic Polyurethane (TPU) and used in the construction of air bladders was evaluated for hygroscopic effects driving delamination and multiple layer fragmentation. These air bladders are observed to suffer delamination during a manufacturing process that involves immersion in an alcohol/water solution. A plausible underlying mechanism is differential swelling and absorption by the laminate constituents. Both room and elevated temperature swelling tests were carried out to find the absorption and swelling coefficients of the constituents. These coefficients served as input into a Finite Element Analysis …

Design And Implementation Of A Modular Human-Robot Interaction Framework, Michael J. Juri

Master's Theses

With the increasing longevity that accompanies advances in medical technology comes a host of other age-related disabilities. Among these are neuro-degenerative diseases such as Alzheimer's disease, Parkinson's disease, and stroke, which significantly reduce the motor and cognitive ability of affected individuals. As these diseases become more prevalent, there is a need for further research and innovation in the field of motor rehabilitation therapy to accommodate these individuals in a cost-effective manner. In recent years, the implementation of social agents has been proposed to alleviate the burden on in-home human caregivers. Socially assistive robotics (SAR) is a new subfield of research …

Monte Carlo Stack-Up Tolerance Analysis Of The Hybrid Rf/Optical Antenna Edge Sensors, Kara Hewson

Master's Theses

The Deep Space Network (DSN), located at the Jet Propulsion Laboratory (JPL), is developing an RF/Optical Hybrid Antenna. This antenna concept will support the reception of high-bandwidth optical deep-space communications with simultaneous support of conventional RF uplink and downlink. The optical system on the antenna consists of sixty-four hexagonal mirrors positioned to form a spherical aperture. To align the mirrors, a Position Opto-Electronic Metrology Sensor (POEMS) system is used to measure the position of each mirror relative to one another. The POEMS system consists of a sender called a collimator, which sends collimated light to the receiving component, called a …

Analytical, Numerical, And Computational Methods To Analyze The Time To Empty Open, Closed, And Variable-Topped Inverted Bottles, Callen Schwefler

Master's Theses

Recent unexpected experimental observations of the emptying of inverted bottles with perforations has generated interest in modeling and simulation of this phenomenon. It was observed that as a perforation, i.e., a small hole at the "top" of the inverted bottle, is added and enlarged, the overall emptying time first increases to a maximum value and then decreases until it reaches a lower limit. The change in emptying time is associated with a transition from jetting, where only water exits the neck, to glugging, a competition between air and water flows at the neck of the bottle.

This paper develops analytical …

Development Of Novel Hardware And Software For Wind Turbine Condition Monitoring, Ryan A. Zhan

Master's Theses

With the increased use of wind turbines as sources of energy, maintenance of these devices becomes more and more important. Utility scale wind turbines can be time consuming and expensive to repair so an intelligent method of monitoring these devices is important. Commercial solutions for condition monitoring exist but are expensive and can be difficult to implement. In this project a novel condition monitoring system is developed. The priority of this system, dubbed the LifeLine, is to provide reliable condition monitoring through an easy-to-install and low-cost system. This system utilizes a microcontroller to collect acceleration data to detect imbalances on …

Ram Air-Turbine Of Minimum Drag, Raymond Akagi

Master's Theses

The primary motivation for this work was to predict the conditions that would yield minimum drag for a small Ram-Air Turbine used to provide a specified power requirement for a small flight test instrument called the Boundary Layer Data System. Actuator Disk Theory was used to provide an analytical model for this work.

Classic Actuator Disk Theory (CADT) or Froude’s Momentum Theory was initially established for quasi-one-dimensional flows and inviscid fluids to predict the power output, drag, and efficiency of energy-extracting devices as a function of wake and freestream velocities using the laws of Conservations of Mass, Momentum, and Energy. …

A Single-Stage Passive Vibration Isolation System For Scanning Tunneling Microscopy, Toan T. Le

Master's Theses

Scanning Tunneling Microscopy (STM) uses quantum tunneling effect to study the surfaces of materials on an atomic scale. Since the probe of the microscope is on the order of nanometers away from the surface, the device is prone to noises due to vibrations from the surroundings. To minimize the random noises and floor vibrations, passive vibration isolation is a commonly used technique due to its low cost and simpler design compared to active vibration isolation, especially when the entire vibration isolation system (VIS) stays inside an Ultra High Vacuum (UHV) environment. This research aims to analyze and build a single-stage …

Improvement Of Labyrinth Seal Leakage Rates Using Additive Manufacturing, Austin L. Gasbarra

Master's Theses

The growing popularity of additive manufacturing in commercial applications has al- lowed for new ideas and new ways of thinking when designing components. Further optimization at the component level is possible, though powder metallurgy is in its infancy. This study explores the possibility of using additive manufacturing to develop better labyrinth seals in turbomachinery. Labyrinth seals have a torturous fluid path with high losses, thus limiting the amount of fluid leakage. These types of seals can be non-rotating, allowing them to better take advantage of the additive manufacturing process due to the absence of rotating stresses. Labyrinth seal performance is …

Design Of A 5 Degree Of Freedom Kinematic Stage For The Dual Crystal Backlighter Imager Diagnostic, Nicholas Nguyen

Master's Theses

The National Ignition Facility (NIF) is home to the world’s most energetic laser. The facility is one of the leading centers in inertial confinement fusion (ICF) experiments to research and understand sustainable fusion energy. To fully document and understand the physics occurring during experiments, precise diagnostics are used for a wide range of purposes. One diagnostic, the crystal backlighter imager (CBI), allows for X-ray imaging of the target at late stages of its implosion.

The aim of this project was to increase the current capabilities of the CBI diagnostic with the addition of a second crystal. This thesis focuses on …

Numerical Methods For Predicting The Dynamic Crushing Response And Energy Absorption Of Composite Aluminum Honeycomb Sandwich Structures, Cody R. Volk

Master's Theses

Edgewise crushing responses of composite aluminum honeycomb sandwich structures were predicted using finite element analysis (FEA) software LS-DYNA by modeling the honeycomb as a material with anisotropic properties. The goal of the project was to develop a process for modeling the sandwich structure to rapidly iterate possible solutions for a safer workstation train table. Current workstation tables are too rigid and may cause injury or death in a head-on collision. Experimental compression tests were used to calibrate the aluminum honeycomb core with material type 26 (MAT 26, honeycomb). A published composite tensile test was used to validate the use of …

Flight Test Data System For Strain Measurement, Zachary David Wilson

Master's Theses

This thesis describes the design and evaluation of two devices to be included in the next generation of the family of devices called the Boundary Layer Data System (BLDS). The first device, called the Quasi-Static Strain Data Acquisition System, is a continuation of the BLDS-M series of devices to be known as the Flight Test Data System (FTDS) that uses a modular approach to acquire non-flow, quasi-static mechanical strain measurements. Various breakout boards and development boards were used to synthesize the device, which were housed by a custom PCB board. The system is controlled by the Simblee^TM System on …

A Novel Fiber Jamming Theory And Experimental Verification, Jared Richard Chafetz

Master's Theses

This thesis developed a novel theory of fiber jamming and experimentally verified it. The theory relates the performance, which is the ratio between the stiff and soft states of a fiber jamming chamber, to three relative design parameters: the ratio of the wall thickness to the membrane inner diameter, the ratio of the fiber diameter to membrane inner diameter, and the number of fibers. These three parameters, when held constant across different chamber sizes, hold the performance constant. To test the theory, three different types of fiber jamming chambers were built in three different sizes. Each chamber was set up …

Investigation Of Design, Manufacture, Analysis, And Test Of A Composite Connecting Rod Under Compression, Thomas Juhl Rohrbach

Master's Theses

Composite materials hold great potential for the replacement of traditional materials in machines utilized on a daily basis. One such example is within an engine block assembly where massive components inherently reduce the efficiency of the system they constitute. By replacing metal elements such as connecting rods, cylinder caps, or a crank shaft with composite alternatives, a significant increase in performance may be achieved with respect to mechanical strength, thermal stability, and durability, while also reducing mass. Exploration of this technology applied to a connecting rod geometry was investigated through a combination of process development, manufacturing, numerical analysis and testing. …

Powder Bed Surface Quality And Particle Size Distribution For Metal Additive Manufacturing And Comparison With Discrete Element Model, Irene Yee

Master's Theses

Metal additive manufacturing (AM) can produce complex parts that were once considered impossible or too costly to fabricate using conventional machining techniques, making AM machines an exceptional tool for rapid prototyping, one-off parts, and labor-intensive geometries. Due to the growing popularity of this technology, especially in the defense and medical industries, more researchers are looking into the physics and mechanics behind the AM process. Many factors and parameters contribute to the overall quality of a part, one of them being the powder bed itself. So far, little investigation has been dedicated to the behavior of the powder in the powder …

Measurement And Analysis Of The Physical And Climatic Distribution Environment For Air Package Shipment, David Guadagnini

Master's Theses

The modern air parcel distribution industry has significantly grown to become one of the most commonly employed methods to quickly transport goods throughout the world. Although it comes with many benefits, including higher speed, greater reliability, and tighter security, the multimodal transport system within it can expose packages to a wide variety of climatic and physical distribution hazards. In a single route of transportation, packages could be included in different types of small delivery vans, large commercial semi trucks, cargo dollies, feeder aircraft, and high altitude commercial jetliners. The varying hazard level presented during distribution could directly weaken the packaging …

Corgi: Compute Oriented Recumbent Generation Infrastructure, Christopher Allen Hunt

Master's Theses

Creating a bicycle with a rideable geometry is more complicated than it may appear, with today’s mainstay designs having evolved through years of iteration. This slow evolution coupled with the bicycle’s intricate mechanical system has lead most builders to base their new geometries off of previous work rather than expand into new design spaces. This crutch can lead to slow bicycle iteration rates, often causing bicycles to all look about the same. To combat this, several bicycle design models have been created over the years, with each attempting to define a bicycle’s handling characteristics given its physical geometry. However, these …

The Effect Of Biocomposite Material In A Composite Structure Under Compression Loading, Benjamin Andrew Sweeney

Master's Theses

While composite structures exhibit exceptional strength and weight saving possibilities for engineering applications, sometimes their overall cost and/or material performance can limit their usage when compared to conventional structural materials. Meanwhile ‘biocomposites’, composite structures consisting of natural fibers (i.e. bamboo fibers), display higher cost efficiency and unique structural benefits such as ‘sustainability’. This analysis will determine if the integration of these two different types of composites are beneficial to the overall structure. Specifically, the structure will consist of a one internal bamboo veneer biocomposite ply; and two external carbon fiber weave composite plies surrounding the bamboo biocomposite. To acquire results …

A Study Of Constant Voltage Anemometry Frequency Response, Alex D. Powers

Master's Theses

The development of the constant voltage anemometer (CVA) for the boundary layer data system (BLDS) has been motivated by a need for the explicit autonomous measurement of velocity fluctuations in the boundary layer. The frequency response of a sensor operated by CVA has been studied analytically and experimentally. The thermal lag of the sensor is quantified by a time constant, M_CVA. When the time constant is decreased, the half-amplitude cut-off frequency, f_CVA, is increased, thereby decreasing the amount of attenuation during measurements. In this thesis, three main approaches have been outlined in theory and tested experimentally …

Design And Analysis Of A Lift Assist Walker, Deep P. Shah

Master's Theses

Walkers provided stability to the elderly but cannot assist a person from sitting to standing. The objective of this project is to present the design and analysis of a lift assist walker. This report discusses the design and analysis of a collapsible lift assist walker capable of lifting a patient up to 250 lbs. from seated to standing in under 10 seconds. The designed walker utilized a two stage scissor mechanism with a gas spring assisted embedded linear actuator.