Engineering Commons^™

Control Of Longitudinal Pitch Rate As Aircraft Center Of Gravity Changes, John Andres Cadwell Jr.

Master's Theses

In order for an aircraft to remain in stable flight, the center of gravity (CG) of an aircraft must be located in front of the center of lift (CL). As the center of gravity moves rearward, pitch stability decreases and the sensitivity to control input increases. This increase in sensitivity is known as pitch gain variance. Minimizing the pitch gain variance results in an aircraft with consistent handling characteristics across a broad range of center of gravity locations.

This thesis focuses on the development and testing of an open loop computer simulation model and a closed loop control system to …

Effects Of Cloud-Induced Photovoltaic Power Transients On Power System Protection, Joel A. Nelson

Master's Theses

As the world strives towards finding alternative sources of power generation, photovoltaic generation has become an increasingly prevalent alternative energy source on power systems world-wide. This paper studies the effects that incorporating photovoltaic generation has on the existing power systems and their power system protection schemes. Along with the addition of this emerging alternative energy source comes the volatility of PV power generation as cloud-cover produces erratic variations in solar irradiance and PV power production. Such variations in PV power may lead to unfavorable operating conditions and power system failures. The issues addressed in this paper include a study of …

Modeling Of A Gyro-Stabilized Helicopter Camera System Using Neural Networks, Nicholas Joseph Layshot

Master's Theses

On-board gimbal systems for camera stabilization in helicopters are typically based on linear models. Such models, however, are inaccurate due to system nonlinearities and complexities. As an alternative approach, artificial neural networks can provide a more accurate model of the gimbal system based on their non-linear mapping and generalization capabilities.

This thesis investigates the applications of artificial neural networks to model the inertial characteristics (on the azimuth axis) of the inner gimbal in a gyro-stabilized multi-gimbal system. The neural network is trained with time-domain data obtained from gyro rate sensors of an actual camera system. The network performance is evaluated …

Multi-Frequency Processing For Lumen Enhancement With Wideband Intravascular Ultrasound, Rory A. Carrillo

Master's Theses

The application of high frequency ultrasound is the key to higher resolution intravascular ultrasound (IVUS) images. The need to further improve the IVUS spatial resolution may drive the transducer center frequency even higher than the current 40 MHz range. However, increasing the center frequency may be challenging as it leads to stronger scattering echoes from blood. The high level of blood scattering echoes may obscure the arterial lumen and make image interpretation difficult. Blood backscatter levels increase with transmission center frequency at a much greater rate compared to arterial tissue. These different frequency dependencies provide a potential method to distinguish …

Asynchronous Mips Processors: Educational Simulations, Robert L. Webb

Master's Theses

The system clock has been omnipresent in most mainstream chip designs. While simplifying many design problems the clock has caused the problems of clock skew, high power consumption, electromagnetic interference, and worst-case performance. In recent years, as the timing constraints of synchronous designs have been squeezed ever tighter, the efficiencies of asynchronous designs have become more attractive. By removing the clock, these issues can be mitigated. How- ever, asynchronous designs are generally more complex and difficult to debug. In this paper I discuss the advantages of asynchronous processors and the specifics of some asynchronous designs, outline the roadblocks to asynchronous …

Class-F Power Amplifier With Maximized Pae, Kai Shing Tsang

Master's Theses

Due to the rapid development of telecommunication devices, operating speeds are getting faster and more power is being consumed by those devices. Therefore, there is a big concern on how to prolong the battery life in order to fit consumers’ needs. Power amplifiers (PA) at the front end of wireless equipment have drawn a big concern from engineers because of their large power consumption in the system. There is a lot research conducted on PA solutions for improving power-added efficiency (PAE) of amplifiers. PAE is a figure of merit representing how efficient the PA converts DC power to RF power. …

Enhanced Cal Poly Super System Simulink Model, Matthew Ogden Mcfarland

Master's Theses

The Cal Poly Sustainable Power for Electrical Resources (SuPER) project is a solar power DC distribution system designed to autonomously manage and supply the energy needs of a single family off-the-grid home. The following thesis describes the improvement and re-design of a MATLAB Simulink model for the Cal Poly SuPER system. This model includes a photovoltaic (PV) array, a lead-acid gel battery with temperature effects, a wind turbine model, a re-designed DC-DC converter, a DC microgrid, and multiple loads. This thesis will also include several control algorithms such as a temperature controlled thermoelectric (T.E.) cooler, intelligent load switching, and an …

Distributed Generation: Issues Concerning A Changing Power Grid Paradigm, Scott G.M. Therien

Master's Theses

Distributed generation is becoming increasingly prevalent on power grids around the world. Conventional designs and grid operations are not always sufficient for handling the implementation of distributed generation units; the new generation may result in undesirable operating conditions, or system failure. This paper investigates the primary issues involved with the implementation of distributed generation and maintaining the integrity of the power grid. The issues addressed include power flow, system protections, voltage regulation, intermittency, harmonics, and islanding. A case study is also presented to illustrate how these issues can be addressed when designing distributed generation installation on an existent distribution system. …

Systems Engineering Analysis And Digital Communication Bus Design For The Cal Poly Super Project, Matt Marcus Camack

Master's Theses

With an expected lifetime of 20 years and an expected cost of $500, the Cal Poly Sustainable Power for Electrical Resources (SuPER) project needed a strong central design. This thesis looks at the work completed by students over the previous 5 years, with an eye on the future, to create the phase 2 design. Part of this new structure focuses on a distributed communication bus for monitoring system health and status. Instead of complex and costly computer or FPGA systems, the new system will run solely with microcontrollers. This reduces costs and will hopefully still be used within 5, 10, …

Pulse Density Modulated Soft Switching Cycloconverter, Jesse Timothy Adamson

Master's Theses

Single stage cycloconverters generally incorporate hard switching at turn on and soft switching at turn off. This hard switching at turn on combined with the slow switching speeds of thyristors (the switch of choice for standard cycloconverters) limits their use to lower frequency applications.

This thesis explores the analysis and design of a pulse density modulated (PDM), soft switching cycloconverter. Unlike standard cycloconverters, the controller in this converter does not adjust thyristor firing angles. It lets only complete half cycles of the input waveform through to the output. This allows and requires a much greater frequency step down from the …

Modular Laser Combat System For Remotely Operated Vehicles: Bridging The Gap Between Computer Simulation And Live Fire, Thomas Edward Fulenwider

Master's Theses

In the emerging industry of small unmanned vehicles, pioneered by small businesses and research institutions, a suitable combat system test platform is needed. Computer simulations are useful, but do not provide the definitive proof of effective operation necessary for deployment of a combat system. What is needed is an affordable simulated weapons system that enables live flight testing without the used of live weaponry.

A framework is developed here for the construction of a simulated weapon using Free Space Optical (FSO) infrared communication. It is developed in such a way to ensure compatibility with a variety of platforms including ground …

High Resolution Simulation Of Synthetic Aperture Radar Imaging, Cindy G. Romero

Master's Theses

The goal of this Master’s thesis is to develop a more realistic simulation of Synthetic Aperture Radar (SAR) that has the ability to image detailed targets, and that can be used for Automatic Target Recognition (ATR). This thesis project is part of ongoing SAR ATR research at California Polytechnic State University (Cal Poly) sponsored by Raytheon Space & Airborne Systems and supervised by Dr. John Saghri.

SAR is a form of radar that takes advantage of the forward motion of an antenna mounted on a moving platform (such as an airplane or spacecraft) to synthetically produce the effect of a …

Multiple Robot Boundary Tracking With Phase And Workload Balancing, Michael Jay Boardman

Master's Theses

This thesis discusses the use of a cooperative multiple robot system as applied to distributed tracking and sampling of a boundary edge. Within this system the boundary edge is partitioned into subsegments, each allocated to a particular robot such that workload is balanced across the robots. Also, to minimize the time between sampling local areas of the boundary edge, it is desirable to minimize the difference between each robot’s progression (i.e. phase) along its allocated sub segment of the edge. The paper introduces a new distributed controller that handles both workload and phase balancing. Simulation results are used to illustrate …

Enhanced Light Extraction Efficiency From Gan Light Emitting Diodes Using Photonic Crystal Grating Structures, Simeon S. Trieu

Master's Theses

Gallium nitride (GaN) light emitting diodes (LED) embody a large field of research that aims to replace inefficient, conventional light sources with LEDs that have lower power, higher luminosity, and longer lifetime. This thesis presents an international collaboration effort between the State Key Laboratory for Mesoscopic Physics in Peking University (PKU) of Beijing, China and the Electrical Engineering Department of California Polytechnic State University, San Luis Obispo. Over the course of 2 years, Cal Poly’s side has simulated GaN LEDs within the pure blue wavelength spectrum (460nm), focusing specifically on the effects of reflection gratings, transmission gratings, top and bottom …

Aperture Coupled Microstrip Antenna Design And Analysis, Michael Paul Civerolo

Master's Theses

A linearly-polarized aperture coupled patch antenna design is characterized and optimized using HFSS antenna simulation software. This thesis focuses on the aperture coupled patch antenna due to the lack of fabrication and tuning documentation for the design of this antenna and its usefulness in arrays and orthogonally polarized communications. The goal of this thesis is to explore dimension effects on aperture coupled antenna performance, to develop a design and tuning procedure, and to describe performance effects through electromagnetic principles.

Antenna parameters examined in this study include the dimensions and locations of the substrates, feed line, ground plane coupling slot, and …

Negative Conductance Load Modulation Rf Power Amplifier, Cody R. Neslen

Master's Theses

The number of mobile wireless devices on the market has increased substantially over the last decade. The frequency spectrum has become crowded due to the number of devices demanding radio traffic and new modulation schemes have been developed to accommodate the number of users. These new modulation schemes have caused very poor efficiencies in power amplifiers for wireless transmission systems due to high peak-to-average power ratios (PAPR). This thesis first presents the issue with classical power amplifiers in modern modulation systems. A brief overview of current attempts to mitigate this issue is provided. A new RF power amplifier topology is …

Standalone Antenna Demonstration System, Alexander James Hempy

Master's Theses

Antenna systems play a significant role in today’s electronic communications. They are essential for cell phones, satellites, radio, and radar among many other important applications. This paper describes the design, assembly, and operation of an antenna demonstration system designed to instill interest in the field of antenna design among high school and undergraduate college students. The system is portable, supplied solely by DC power supplies, easily reproducible, and includes rotational axes to illustrate antenna performance limitations and requirements. It provides a visual indication of wireless signal strength and demonstrates several antenna performance characteristics including polarization, gain and directivity, radiation patterns …

A Constant Conduction Angle Biased Rf Power Amplifier For Improved Linearization In Class C Operation, Greg Lacaille

Master's Theses

Class C power amplifiers offer higher efficiency than class B power amplifiers, but suffer from poor linearity. A feedback based biasing system to improve the linearity of a class C power amplifier is designed. A class B amplifier with a gain of 20 dB and 20 MHz bandwidth at 900 MHz acts as the launching point for the design. The biasing and output network of the class B power amplifier is modified to produce a class C amplifier at conduction angles of 180°, 162°, 126°, 90°, and 54°. A feedback based biasing system, which uses two matched and scaled down …

Improved Rf Power Extraction From 1.55um Ge-On-Soi Pin Photodiodes With Load Impedance Optimization, Andrew L. Huard

Master's Theses

VLSI miniaturization has created the need for high-density, low-cost, monolithically-integrated optical interconnects. High output power photodetectors are needed to directly drive load circuitry, which improves the noise performance and dynamic range of optical communications links by eliminating a post amplifier stage. Elimination of the post amplifier also reduces circuit cost and complexity. A new Si-Ge PIN waveguide photodiode with 31GHz bandwidth and 93% quantum efficiency at 1550nm has been developed by Yin et al., which was fabricated using standard CMOS processes on a Silicon substrate. This thesis demonstrates a method for improving the RF power extraction from these photodiodes by …

Wave Energy Converter Performance Modeling And Cost Of Electricity Assessment, Dmitri Jarocki

Master's Theses

California is experiencing a rapid increase in interest for the potential of converting ocean waves into clean electricity. Numerous applications have been submitted for the permitting of such renewable energy projects; however the profitability, practicability, and survivability have yet to be proven. Wave energy conversion technology has steadily matured since its naissance in the 1970’s, several wave energy power installations currently exist, and numerous plans for commercial power plant are in the works on the shores of multiple continents. This study aims to assess the economic viability of two proposed commercial wave energy power plant projects on the Central California …

Space-Time Adaptive Processing With Multi-Staged Wiener Filter And Principal Component Signal Dependent Algorithms, Zheng N. Zhou

Master's Theses

Space-time Adaptive Processing (STAP) is a two-dimensional filtering technique for antenna array with multiple spatial channels. The name "space-time" describes the coupling of these spatial channels with pulse-Doppler waveforms. Applications for STAP includes ground moving target indicator (GMTI) for airborne radar systems.

Today, there are strong interests to develop STAP algorithms for operations in “sample starved” environments, where intense environmental interference can reduce STAP capacity to detect and track ground targets. Careful applications of STAP can effectively overcome these conditions by suppressing these interferences and maximize the signal to interference plus noise ratio (SINR). The Multi-stage Wiener filter (MWF) and …

Receive Sensitivity Characterization Of The Polysat Satellite Communication System, Ivan M. Bland

Master's Theses

Following the successful launch of CP3 and CP4, the PolySat team noticed an unreliable uplink to both satellites. A significant problem with the PolySat COMM system is poor receive sensitivity of the communications system. Efforts have been made to improve the uplink margin, but without proper characterization of the receiver sensitivity, the problem cannot be fully addressed. By developing an accurate method of measuring receive sensitivity, a methodical approach can be used to properly diagnose the communication system and link budget. Two revisions of the PolySat COMM system will be measured and compared. An in-depth study of the PolySat COMM …

High Voltage Resonant Self-Tracking Current-Fed Converter, Scott Logan Mcclusky

Master's Theses

High voltage power supply design presents unique requirements, combining safety, controllability, high performance, and high efficiencies. A new Resonant Self-Tracking Current-Fed Converter (RST-CFC) is investigated as a proof-of-concept of a high voltage power supply particularly for an X-ray system. These systems require fast voltage rise times and low ripple to yield a clear image.

The proposed converter implements high-frequency resonance among discrete components and transformer parasitics to achieve high voltage gain, and the self-tracking nature ensures operation at maximum gain while power switches achieve zero-voltage switching across the full load range. This converter exhibits an inherent indefinite short-circuit capability. Theoretical …

Near Real-Time Exercise Machine Power Statistics Reporting, Brendan C. Asche

Master's Theses

Cal Poly’s Recreation Center expansion project provides an opportunity to implement Energy Harvesting From Exercise Machines (EHFEM). Part of this implementation is a system that reports the exercise machines’ energy production. Although products capable of reporting exercise machine energy harvesting statistics exist, they have limited capabilities. This thesis project defends a system capable of reporting exercise machine power statistics in near real-time.

The system consists of display, database, and power measurement modules. The display module presents statistics in an interactive, graphical, and widely-accessible way. The database module provides an efficient way of organizing and accessing stored statistics. Multiple power measurement …

The Design And Manufacture Of A Light Emitting Diode Package For General Lighting, Michael S. Krist

Master's Theses

Lighting technologies have evolved over the years to become higher quality, more efficient sources of light. LEDs are poised to become the market standard for general lighting because they are the most power efficient form of lighting and do not contain hazardous materials. Unfortunately, LEDs pose unique problems because advanced thermal management is required to remove the high heat fluxes generated by such relatively small devices. These problems have already been overcome with complex packaging and exotic materials, but high costs are preventing this technology from displacing current lighting technologies.

The purpose of this study is to develop a low-cost …

Design Techniques To Improve Time Dependent Dielectric Breakdown Based Failure For Cmos Circuits, Emanuel S. Tarog

Master's Theses

This project investigates the failure of various CMOS circuits as a result of Time Dependent Dielectric Breakdown (TDDB) and explores design techniques to increase the mean time to failure (MTTF) of large-scale circuits. Time Dependent Dielectric Breakdown is a phenomenon where the oxide underneath the gate degrades as a result of the electric field in the material. Currently, there are few well documented design techniques that can increase lifetime, but with a tool chain I created called the MTTF Analyzing Program, or MAP, I was able to test circuits under various conditions in order to identify weak links, discover relationships, …

Denoising Of Natural Images Using The Wavelet Transform, Manish Kumar Singh

Master's Theses

A new denoising algorithm based on the Haar wavelet transform is proposed. The methodology is based on an algorithm initially developed for image compression using the Tetrolet transform. The Tetrolet transform is an adaptive Haar wavelet transform whose support is tetrominoes, that is, shapes made by connecting four equal sized squares. The proposed algorithm improves denoising performance measured in peak signal-to-noise ratio (PSNR) by 1-2.5 dB over the Haar wavelet transform for images corrupted by additive white Gaussian noise (AWGN) assuming universal hard thresholding. The algorithm is local and works independently on each 4x4 block of the image. It performs …

Charge Injection And Clock Feedthrough, Jonathan Yu

Master's Theses

Turning off a transistor introduces an error voltage in switched-capacitor circuits. Circuits such as analog-to-digital converters (ADC), digital-to-analog converters (DAC), and CMOS image sensor pixels are limited in performance due to the effects known as charge injection and clock feedthrough. Charge injection occurs in a switched-capacitor circuit when the transistor turns off and disperses channel charge into the source and drain. The source, which is the sampling capacitor, experiences an error in the sampled voltage due to the incoming channel charge. Simultaneously, the coupling due to gate-source overlap capacitance also contributes to the total error voltage, which is known as …