Engineering Commons^™

Elastic Actuator For Robotic Leg, Bruce Berg, Allan Pham, Madeline Slater, Sofie Zalatimo

Mechanical Engineering

The Cal Poly Legged Robots Group (CPLRG) is developing a 12 degree of freedom robot with the goal of eventually performing highly dynamic movements such as jumps and flips. During such movements, large impact forces will be experienced by the leg, potentially resulting in damage to physical components such as the motors. The scope of this project is to integrate elastic elements into the quadruped legs to reduce shock loads on the motors and improve the efficiency of the legs through energy storage. The key stakeholders for this project are Professor Charlie Refvem and Dr. Simon Xing. Other stakeholders include …

Automated Optimization Of Membrane Bioreactor Performance Using Machine Learning, Janessa Cayabyab, Isabella Lopez, Oluwatomisin Opaleye, Jessica Stone

Bioengineering Senior Theses

Membrane bioreactors (MBRs) are increasingly employed in biomanufacturing due to their ability to produce high-quality effluent and support complex biological processes. However, membrane fouling remains a critical operational challenge, driving increased energy consumption, frequent cleaning cycles, elevated transmembrane pressure (TMP), and accelerated membrane degradation. Conventional operator-driven cleaning strategies are reactive by nature and insufficient for managing the dynamic, nonlinear fouling behavior characteristic of full-scale MBR systems.

This study presents a data-driven machine learning pipeline for predicting TMP and fouling behavior in an industry-scale MBR system, with the goal of optimizing cleaning schedules and extending membrane lifespan. A Random Forest regression …

Leveraging Ict Adoption And Electricity Access For Sustainable Agricultural Productivity Among Nigerian Households, Menghan Huang, Qin Chen, Oluwayemisi Kadijat Adeleke, Mamdouh Abdulaziz Saleh Al-Faryan

The Philippine Agricultural Scientist

This study investigated ICT adoption (mobile phone and internet usage), access to electricity, and their impact on household agricultural productivity in Nigeria, Africa’s largest economy. Utilizing Wave 4 (2018 to 2019) Living Standards Measurement Study–Integrated Survey on Agriculture (LSMS–ISA) data covering 4,980 household heads, this study applied logit regression and Propensity Score Matching (PSM) for estimation, alongside a Cobb-Douglas production function to analyze input contributions to agricultural output. The findings revealed that the age, residential location, educational level, and access to electricity of household heads significantly determine technology adoption among farming households. Furthermore, ICT adoption exhibits a significant, positive relationship …

Rc-Nf: Robot-Conditioned Normalizing Flow For Real-Time Anomaly Detection In Robotic Manipulation, Shijie Zhou, Bin Zhu, Jiarui Yang, Xiangyu Zhao, Jingjing Chen, Yu-Gang Jiang

Research Collection School Of Computing and Information Systems

Recent advances in Vision-Language-Action (VLA) models have enabled robots to execute increasingly complex tasks. However, VLA models trained through imitation learning struggle to operate reliably in dynamic environments and often fail under Out-of-Distribution (OOD) conditions. To address this issue, we propose Robot-Conditioned Normalizing Flow(RC-NF), a real-time monitoring model for robotic anomaly detection and intervention that ensures the robot's state and the object's motion trajectory align with the task. RC-NF decouples the processing of task-aware robot and object states within the normalizing flow. It requires only positive samples for unsupervised training and calculates accurate robotic anomaly scores during inference through the …

Design And Optimization Of A Bluff Body For Energy Harvesting Of Transverse Galloping Induced By Low-Speed Wind Using Bernstein Polynomial Equations, Youssef Wael Abdelmoneim

Theses and Dissertations

In this thesis, a computational framework is proposed for optimizing the aerodynamic shape of bluff bodies used in galloping-based wind energy harvesters. The system targets low-wind speed environments, where normal wind turbines are not effective, offering a potential alternative to batteries used for powering small electronic devices such as wireless sensors. The design relies on the galloping effect, where airflow around a bluff body induces transverse oscillations that drive an energy conversion mechanism. To generate efficient bluff body geometry, the Class-Shape Transformation (CST) method is used to define a wide range of candidate shapes with minimal design parameters. These shapes …

Capstone Review: Warn Winch Proximity Sensor, Leana Girton

University Honors Theses

This thesis reviews the mechanical engineering capstone project that designed a winch proximity sensor for WARN Industries. WARN is very interested in developing this product for market as a safety and ease-of-use accessory, and working with Portland State University was the first step in this process. A group of four mechanical engineering and four electrical engineering capstone students collaborated to research sensor types, test the selected methods, and design and build a prototype. The final design implements an inductive ring, a mechanical button, and bluetooth signaling. The project succeeded in prototyping a proximity sensor for WARN, who will have access …

Quantum And Conventional Informatics Studies Of Synthesis Energetics And Defect Formation In Nitride Crystal Epitaxy, Andrew Steven Messecar

Dissertations

Machine learning is a valuable approach for the processing and analysis of complex information. By estimating relationships from recorded data, machine learning methodologies can be effective strategies for pattern recognition, enabling investigations and technological applications based thereon. The potential for improved understanding of high-dimensional data has drawn interest towards machine learning from across the sciences, including the research and development of new and improved material systems. In the context of experimental materials research, much of the reported efforts to incorporate machine learning into conventional practice have been primarily focused on either the enhanced analysis of characterization experiment data or the …

Building Services Engineering May/June 2026

Building Services Engineering

No abstract provided.

The Use Of Modular Construction To Improve Schedule Efficiency, Brandon Ritchie

Construction Management

The construction industry continues to face growing pressure to deliver projects on tighter schedules with fewer resources. Modular construction has emerged as a delivery method with the potential to improve schedule efficiency by allowing off site fabrication and on site work to occur simultaneously. This research examines how modular construction affects schedule performance compared to traditional construction methods. When modular construction is well coordinated, project schedules will show improved efficiency compared to traditionally built projects. Qualitative interviews were conducted with members of the Whiting Turner team on the Cal Poly Student Housing Project, backed up by a review of schedule …

Skip The Grid: Bringing Solar Energy To The Navajo Nation, Makaela L. Zavala

Construction Management

Skip the Grid is an interdisciplinary service project in which California Polytechnic State University (Cal Poly) students partner with Heart of America and SOLV Energy to install off-grid solar systems for families in the Navajo Nation and Hopi Reservation. The project aims to address energy inequity by providing reliable electricity for lighting, refrigeration, and essential daily needs. This paper focuses on the communications and logistics planning required to support a large-scale service project involving over twenty students and multiple partner organizations. The methodology included coordinating travel, organizing team assignments, managing documentation, and maintaining communication throughout the trip. The project resulted …

Skip The Grid: Bringing Power To Navajo Nation Through Off-Grid Solar Systems, Maggie Papaharisi

Construction Management

Skip the Grid is an interdisciplinary service-learning project where California Polytechnic State University (Cal Poly) students partner with Heart of America and SOLV Energy to install off-grid solar systems for families in the Navajo Nation who do not have reliable access to electricity. Due to the remote location and high cost of infrastructure, a significant portion of households lack basic utilities, making access to lighting, refrigeration, and power difficult. During the 2026 project, a team of students from multiple disciplines spent several months preparing before traveling to Arizona, where installation teams completed solar systems in 50 homes over three days. …

Modular Student Housing At California Polytechnic State University, San Luis Obispo: A Case Study On Efficiency And Implementation, Michelle Lara

Construction Management

As universities continue searching for ways to deliver student housing more efficiently, volumetric modular construction has emerged as a potential alternative to traditional construction methods. However, there is limited documentation on how modular student housing projects are implemented on active California State University campuses. This study examines the implementation of volumetric modular construction on the California Polytechnic State University Student Housing Project through a qualitative case study approach. Data was collected through interviews with project personnel involved in construction management, project engineering, and fire and life safety compliance, along with a review of existing literature. While the project demonstrated several …

Adaptive Position Sensor Harmonic Compensation In Pmsm Drives, Gayan Dissanayake

Masters Theses

Permanent Magnet Synchronous Machines (PMSMs) have emerged as a preferred class of electromechanical energy converters due to their high efficiency, high torque density, and other inherent advantages. Accurate rotor position information is essential for proper commutation and effective field-oriented control (FOC), making precise position sensing critically important. In practice, however, harmonic errors introduced by the position sensing subsystem can lead to undesirable torque ripple and degraded performance. Most existing approaches for mitigating these errors are passive in nature and lack the capability to actively adapt to harmonic variations under changing operating conditions. Since the harmonic content in the position can …

Study Of Plasma Modification Effects On Cell Proliferation Of 3-D Printed Poly Lactic Acid (Pla) Structures, Temiloluwa Nathan

Masters Theses

3-d printing of structures has recently been adopted for a large number of applications including in-vitro lab-on-chip, organ-on-chip and other bioengineering applications. This thesis presents the results of our investigations on the use of a Poly Lactic Acid (PLA) structures for cell proliferation and their potential application for targeted drug delivery and Organ-on-a-Chip applications. As the previous investigations by the group indicated the requirement of surface modification of these printed structures, this study mainly focusses on the plasma surface modification of 3-D printed PLA structures and its impact on cell growth in different conditions. The first component focused on improving …

Real Time Grid Connected Der Inverter Control Fault Ride Through Model In Accordance With Ieee 1547–2018 Standard, Mark Joseph Booge

Masters Theses

Distributed Energy Resources (DERs) include inverter-based power generation units, which are increasing in demand due to the rising consumption of energy, need for improved grid stability, and other environmental factors. DERs can either supply or supplement the grid using different control strategies depending on the grid’s needs. IEEE standard 1547-2018 dictates the interconnection and operation requirements of grid-connected DERs under nominal and abnormal voltage conditions. Although inverter ride-through operation has been widely studied, the effects of the standard’s time-based requirements within a distribution grid system require further investigation.

This study investigates how the IEEE 1547-2018 time-based ride-through requirements affect a …

Understanding The Effect Of Scaling On Aerodynamic Force Analysis Of The Nrel Phase Vi Wind Turbine, Patrick R. West

Masters Theses

It is challenging for small models and prototypes to accurately reflect the aerodynamic performance of a full-scale wind turbine, especially for offshore turbines. It is also not economical to build full-scale models for prototype testing. Scaling makes it possible to modify the dimensions for computational simulations, simplify the prototype construction and testing process, and make aerodynamic load analysis applicable to larger blade diameters. In this work, a model is presented that considers the effects of geometric scaling by modifying the incoming windspeeds and rotational speed of the turbine rotor in capturing aerodynamic load through Computational Fluid Dynamics. The National Renewable …

Finite Element Analysis And Computational Fluid Dynamics To Design And Analyze A Liquid Cooling System For An Integrated Charger Inverter System, Pihillawala Wijethunga

Masters Theses

This work presents a computational and experimental investigation into the thermal management of power electronic modules for an electric vehicle (EV) integrated charger-inverter (ICI) system, with a focus on the Inverter module, Dual Active Bridge (DAB) converter with a High- Frequency Transformer (HFT) with an external leakage inductor. Analytical loss models are used to calculate conduction and switching losses for the DAB and inverter SiC MOSFET modules, and the Improved Generalised Steinmetz Equation is applied to determine HFT core and winding losses. The adequacy of passive natural convection as a thermal management strategy is first assessed, and its limitations at …

High-Density Power Conversion: Analyzing High-Frequency Transformer Scaling Laws And Grid-Filter Efficacy In Integrated Charger Inverters, Thilina Lakshan Dissanayakage

Masters Theses

This thesis investigates frequency scaling in high-frequency transformer (HFT) used in Dual Active Bridge (DAB) converters and evaluates different LCL filter design methodologies for grid-connected applications. The study explores the impact of operating frequency on transformer size reduction, efficiency, and overall performance by analyzing HFT designs at 50 kHz, 100 kHz, and 400 kHz. It is expected that increasing the switching frequency enables significant reduction in transformer volume, while introducing trade-offs in efficiency due to increased core and copper losses. In parallel, the thesis examines and compares three LCL filter design approaches under identical operating conditions using a 1 kW …

Tracking Continuous Non-Differentiable Trajectories In Euler–Lagrange Systems With Continuous Dynamics, Nilay Kant

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Tracking controllers for Euler–Lagrange systems are designed under the assumption that reference trajectories are continuous, and at least twice differentiable with respect to time. However, this assumption precludes several use cases, such as when a robot end-effector must track a path with corners at constant speed. This paper introduces the control design for tracking continuous but non-differentiable trajectories in fully actuated Euler–Lagrange systems that have continuous-time dynamics. The proposed controller combines a continuous feedback law with impulsive inputs, that are intermittently applied at the instants of non-differentiability. A Lyapunov stability analysis establishes global exponential convergence of the tracking error to …

Can Generative Ai Make Farming Decisions? Current Status And Future Pathways: A Case Study In Row Crop Production With Chatgpt, Nipuna Chamara, Yufeng Ge, Joe Luck, Yu Pan, Saleh Taghvaeian, Cory Walters, Christopher Proctor, Daran Rudnick, Daren Redfearn

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The agricultural decision-making process is experience-based, knowledge-dependent, time-sensitive, complex, and driven by historical data. Planting, fertilization, irrigation, and chemigation are key categories in farm decision-making, and currently there is no one-shot decision-support tool that covers all these activities. Generative Artificial Intelligence (AI) models are more advanced than traditional machine learning and deep learning models. These models have been trained on vast amounts of data from the internet, allowing them to accept unstructured data in various forms and generate human-like text, solutions to problems, and scenario predictions. Given this capability, we became interested in exploring the potential of generative AI in …

Gps Tracking Smart Dash Cam Capstone Review, Simrah Saleem

University Honors Theses

This thesis details our design, implementation, and collaborative development of an intelligent vehicle logging system built on a Raspberry Pi 5. Unlike standard consumer dash cams that act as closed "black boxes," our system uses a dual-camera stereo vision setup integrated with centimeter-level accuracy. While we successfully built a functional Proof of Concept capable of event-triggered recording, dual-monitor visualization, and smart detection and recognition, this paper focuses on our engineering journey and the real-world challenges we faced. Using an Agile framework, we split into three specialized sub-teams to handle hardware, database, and interface design in parallel. This structure created unique …

An Exploratory Latent Segmentation Approach To Account For Temporally Shifting Parameters In Driver Injury-Severity Models, Tanmoy Bhowmik, Shahrior Pervaz, Fred Mannering, Naveen Eluru

Civil and Environmental Engineering Faculty Publications and Presentations

Temporally shifting parameters in crash severity modeling is a well-documented phenomenon, with growing evidence suggesting that the influence of explanatory variables changes over time due to shifts in driver behavior, vehicle technology, and roadway conditions. Many studies have examined this issue by comparing the temporal stability of adjacent-year data using a variety of modeling frameworks that have often assumed a homogenous effect of explanatory variables across the entire crash population. The current research effort departs from past work in two ways. First, it compares data separated by multiple years (instead of comparing adjacent years), and second, it tests the homogeneous …

Efficient Mathematical Modeling And Synthesis Of Realistic Musical Instrument Sounds, Andrew Chookaszian

Master's Theses

This thesis develops and evaluates a compact parametric additive synthesis model for isolated musical instrument tones. The method analyzes a single-note recording, estimates its fundamental frequency, extracts harmonic amplitude and frequency behavior, and stores the sound as a reduced set of interpretable parameters. These parameters include the note duration, pitch, per-harmonic amplitude envelopes, phase information, and amplitude- and frequency-modulation vibrato parameters. The stored model is then used to resynthesize the tone without directly using the original audio waveform.

The model was evaluated using synthetic signals, real instrument samples, objective error metrics, storage comparisons, pitch and duration modification tests, and listening …

Hamster: Hybrid-Actuated Mobile Spherical Terrain Exploration Rover, Winnie Gao

Master's Theses

The expansion of space exploration to increasingly challenging planetary environments requires mobility systems capable of extreme traversal capabilities and operational reliability. This thesis presents the design, development, and testing of a low-cost Hybrid-Actuated Mobile Spherical Terrain Exploration Rover (HAMSTER) intended for use on a planetary surface exploration mission. HAMSTER uses a pendulum-based actuation method for steering and an actuated internal shaft to propel the vehicle forward. The internal structure includes a two-tiered central case composed of the navigation control module, accelerometer, motor controller, primary DC motor, battery, voltage regulators, Raspberry Pi, pendulum servo motor, and drive shafts. Additive manufacturing through …

Design And Implementation Of An Embedded Control System For The Cal Poly Spacecraft Attitude Dynamics Simulator, Neil Mahesh Bedagkar

Master's Theses

This thesis presents the development of a cascaded reaction wheel control system for Cal Poly's Spacecraft Attitude Dynamics Simulator. This work considers system architecture, empirical modeling, high-fidelity simulation, embedded firmware, hardware integration, and experimental characterization. In discrete-time simulation, it is shown that nonlinear direct model reference adaptive control (NDMRAC) enables a nonlinear, partially known plant with realistic actuator dynamics to track the response of a canonical second-order transfer function, with settling time within 4.67% and percent overshoot within order of magnitude of the second-order response. In hardware, the feasibility of a cascaded reaction wheel control architecture is experimentally demonstrated, achieving …

Trustworthy Intelligence Fusion For Search And Rescue: Designing Grounded And Secure Multi-Agent Ai For Mission Decision Support, Yayun Tan

Master's Theses

Search and rescue (SAR) operations require teams to integrate uncertain information under severe time pressure. Large language model (LLM)-based multi-agent systems (MAS) can support decision-making, but they also risk producing hallucinated outputs and processing unreliable or malicious data. This thesis addresses these risks through three linked studies. First, it proposes a modular eight-agent SAR MAS architecture that reflects the structure of real SAR missions by assigning specialized roles to different agents. Second, it introduces a post-hoc probabilistic verification framework that checks LLM agent outputs against a probabilistic knowledge graph built from historical SAR incidents.  Third, the thesis examines indirect adversarial …

Characterization Of The Thermally Driven Red Hue Effect In Coated And Uncoated Concrete Systems: Implications For Post-Fire Assessment In Wildland Urban Interface Communities, Juan C. Palominos Jr

Master's Theses

The increasing frequency and intensity of Wildland-Urban Interface (WUI) wildfires, such as the destructive 2025 Pacific Palisades Fire that destroyed over 6,000 structures, have underscored the urgent need for rapid post-fire safety assessment methodologies. This study sought to quantitatively characterize the Thermally Driven Red Hue Effect (TRHE), a unique, irreversible color shift observed in architectural coatings and concrete substrates, to determine its reliability as a permanent visual record of thermal exposure. Concrete substrates were formulated with three distinct coarse aggregates: gold granite (14.7% Fe), red cinder (22.4% Fe), and green rock (33.6% Fe) and coated with a 20 PVC waterborne …

Space Quacker Advanced Development (Squad): Lora Modulation On A Leo Cubesat Mission For Evaluation Of 916 Mhz Uplink, Samantha Brunton

Master's Theses

The LoRa Modulation format was developed by SEMTECH in 2018 and has revolutionized terrestrial Internet of Things (IoT) networks. LoRa (Long Range) has been successfully demonstrated as a long-range, low-data-rate communication modulation format and packet protocol for low-power terrestrial applications. LoRa offers low power consumption, low cost, robust signal sensitivity, and long communication range. Recently, interest has grown in using LoRa communication in Low Earth Orbit (LEO) satellite systems, especially for global IoT connectivity. Previous studies have investigated the theoretical feasibility and simulated the performance of LoRa satellite communication. Companies such as Lacuna Space have demonstrated the practical potential of …

Design And Development Of A Resonance Ignition System Using Gaseous Propellants, Benjamin J. Hoefer

Master's Theses

This work presents the development and experimental evaluation of a resonance igniter (RI) operating with premixed gaseous propellants. Resonance ignition is a non-electrical ignition concept in which an underexpanded jet impinges on a closed-end Hartmann–Sprenger tube (HST), generating cyclic compression and expansion waves that rapidly heat gas near the tube endwall. A modular experimental system was designed and built to investigate resonance ignition using methane–air and methane–oxygen mixtures. The system includes a supplemental configuration that may probe for mixture conditions favorable to ignition, informing RI testing. Pressure and temperature measurements were used to characterize pressure control, mixture pressure ratio (MPR), …

Analysis And Design Of A 2-Bit Millimeter-Wave Reconfigurable Intelligent Surface And Investigation Of Fss-Assisted Angular Stability, Max Spalek

Master's Theses

Millimeter-Wave (mm-wave) technology utilizes high frequency spectrum and can deliver multi-gigabit speeds, ultra-low latency, and massive bandwidth capacity. However, this technology is rather new and many technical challenges remain. On the other hand, Reconfigurable Intelligent Surfaces (RIS) have emerged as promising structures for controllable electromagnetic wavefront manipulation in wireless communication systems. This thesis presents the design of a 2-bit RIS unit-cell element operating throughout the 30–34 GHz mm-wave band, where the structure was progressively refined from an initial resonating geometry toward a grounded reflective RIS configuration. The proposed structure utilizes PIN-diode switching states to produce four discrete reflected phase states …