Virtual reality is becoming more popular and accessible to a broaderaudience, since practically every modern smartphone can be used. The problemwith new components of a technology is the lack of guidelines for the developers.In this thesis, a set of mobile virtual reality games were analysed and broken downinto its core interactions. These interactions were then isolated and implemented ina test application to be the base for a user study. A description of theimplementation was presented focusing on these interactions. The purpose of theuser study was to compare the different interactions and compare them to atraditional controller. From this, guidelines for mobile virtual reality interactionswere developed by analysing the result comparing the interactions for both gamersand non-gamers performance in the user study. The results of this thesis showedthat there are more preferred interactions in virtual reality and that both people thatplay video games, and those who do not, prefer virtual reality interactions over atraditional controller in many cases.

Over the past 20 years research into miniature actuators has been increasing. In addition to having a compact geometry, desirable characteristics for miniature actuators include having a large power-to-weight ratio, fast response, fine resolution of movement and high power efficiency. In the first part of this thesis the design of a miniature rotary robot joint is presented. Two single acting miniature cylinders each with a bore diameter of 4 mm drive the joint using water as the hydraulic fluid. The cylinders are mated to a rack and pinion mechanism that converts the opposing linear motion of the cylinders shafts into rotation. Also within the design, a novel position sensor using magnetic field sensing technology is presented. Overall, the joint measures 11 mm wide x 8.8 mm high x 150 mm long. In the second part of this thesis a hydraulic servo positioning system is presented along with a novel valve modeling technique and two position control strategies. Four low-cost, 3-way on/off solenoid valves were used to control the flow of the water in and out of the cylinders. The two nonlinear position controllers employed were a position-velocity-acceleration plus model-based feedforward controller (PVA+FF) and a novel PVA + FF plus sliding mode controller. For experiments involving horizontal rotation of the joint while carrying no load the PVA +FF controller achieved a steady-state error of ± 0.77° or ± 0.06 mm in terms of rack position. The steady-state error produced by the PVA + FF plus sliding mode controller was ± 0.85° or ± 0.07 mm. The maximum tracking error produced by both controllers was 5° or 0.41 mm and occurred during the initial cycloidal rising portion of a 120° displacement. The root mean square error (RMSE) of the PVA + FF and PVA + FF plus sliding mode controllers were 42% and 54% less than that produced by a linear PVA controller. Both controllers were found to be robust to changes in payload. This was experimentally verified by adding masses of 6.5 g and 13.5 g to the end of the output link of the joint. By conducting similar experiments in the vertical direction it was found that the PVA + FF plus sliding mode controller was more robust, achieving on average a 30% reduction in RMSE compared to the FF + PVA controller. / Thesis / Master of Applied Science (MASc)

The coatings produced by an atmospheric plasma spray process (APSP) must be of uniform quality. However, the complexity of the process and the random introduction of noise variables such as fluctuations in the powder injection rate and the arc voltage make it difficult to control the coating quality that has been shown to depend upon mean values of powder particles' temperature and speed, collectively called mean particles' states (MPSs), just before they impact the substrate. Here we use a science-based methodology to develop an adaptive controller for achieving consistent MPSs. We first identify inputs into the APSP that significantly affect the MPSs, and then formulate a relationship between these two quantities. When the MPSs deviate from their desired values, the adaptive controller based on the model reference adaptive controller (MRAC) framework is shown to successfully adjust the input parameters to correct them. The performance of the controller is tested via numerical experiments using the software, LAVA-P, that has been shown to well simulate the APSP. The developed adaptive process controller is further refined by using sigma (σ) adaptive laws and including a low-pass filter that remove high-frequency oscillations in the output. The utility of the MRAC controller to achieve desired locations of NiCrAlY and zirconia powder particles for generating a 5-layered coating is demonstrated. In this case a pure NiCrAlY layer bonds to the substrate and a pure zirconia makes the coating top. The composition of the intermediate 3 layers is combination of the two powders of different mass fractions. By increasing the number of intermediate layers, one can achieve a continuous through-the-thickness variation of the coating composition and fabricate a functionally graded coating. / Doctor of Philosophy / Canned food sold in a grocery store have cans' interior surface coating with a polymer to increase the shelf life of the food. Similarly, many parts in an automobile have coatings to protect them from corrosion and possibly wear and tear. A process used to produce these coatings is rather complex and involves several variables. An undesired change these variables affects the coating quality. Automatically controlling a coating process is like a cruise control in a car. It should detect which variables have changed and either take appropriate corrective actions or shut down the process if it cannot be corrected or alert an operator to stop the process. In this work we have developed a controller to adaptively adjust the input parameters for an atmospheric plasma spray process (APSP) often used to produce thermal barrier coatings in gas turbines and blades of aircraft jet engines. These coatings hinder the flow of heat from the hot exhaust gases to the blades thereby prolonging their life span.

Concurrent software has been widely utilizing in computer systems owing to the highly efficient computation. However, testing and verifying concurrent software remain challenging tasks. This matter is not only because of the non-deterministic thread interferences which are hard to reason about but also because of the large state space due to the simultaneous path and interleaving explosions. That is, the number of program paths in each thread may be exponential in the number of branch conditions, and also, the number of thread interleavings may be exponential in the number of concurrent operations. This dissertation presents a set of new methods, built upon symbolic execution, a program analysis technique that systematically explores program state space, for testing concurrent programs. By modeling both functional and non-functional properties of the programs as assertions, these new methods efficiently analyze the viable behaviors of the given concurrent programs. The first method is assertion guided symbolic execution, a state space reduction technique that identifies and eliminates redundant executions w.r.t the explored interleavings. The second method is incremental symbolic execution, which generates test inputs only for the influenced program behaviors by the small code changes between two program versions. The third method is SYMPLC, a technique with domain-specific reduction strategies for generating tests for the multitasking Programmable Logic Controller (PLC) programs written in languages specified by the IEC 61131-3 standard. The last method is adversarial symbolic execution, a technique for detecting concurrency related side-channel information leaks by analyzing the cache timing behaviors of a concurrent program in symbolic execution. This dissertation evaluates the proposed methods on a diverse set of both synthesized programs and real-world applications. The experimental results show that these techniques can significantly outperform state-of-the-art symbolic execution tools for concurrent software. / Doctor of Philosophy / Software testing is a technique that runs software as a black-box on computer hardware multiple times, with different inputs per run, to test if the software behavior conforms to the designed functionality by developers. Nowadays, programmers have been increasingly developing multithreaded and multitasking software, e.g., web browser and web server, to utilize the highly efficient multiprocessor hardware. This approach significantly improves the software performance since a large computing job can now decompose to a set of small jobs which can then distribute to concurrently running threads (tasks). However, testing multithreaded (multitask) software is extremely challenging. The most critical problem is the inherent non-determinism. Typically, executing sequential software with the same input data always results in the same output. However, running a multithreaded (multitask) software multiple times, even under the same input data, may yield different output in each run. The root reason is that concurrent threads (tasks) may interleave their running progress at any time; thus the internal software execution order may be altered unexpectedly, causing runtime errors. Meanwhile, finding such faults is difficult, since the number of all possible interleavings can be exponentially growing in the number of concurrent thread (task) operations. This dissertation proposes four methods to test multithreaded/multitask software efficiently. The first method summarizes the already-tested program behaviors to avoid future testing runs that cannot lead to new faults. The second method only tests program behaviors that are impacted by program changes. The third method tests multitask Programmable Logic Controller (PLC) programs by excluding infeasible testing runs w.r.t the PLC semantics. The last method tests non-functional program properties by systematic concurrency analysis. This dissertation evaluates these methods upon a diverse set of benchmarks. The experimental results show that the proposed methods significantly outperform state-of-the-art techniques for concurrent software analysis.

Electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) are gaining popularity because they are more environmentally friendly, less noisy and more efficient. These vehicles have batteries can be charged by on-board battery chargers that can be conductive or inductive. In conductive chargers, the charger is physically connected to the grid by a connector. With the inductive chargers, energy can be transferred wirelessly over a large air-gap through inductive coupling, eliminating the physical connection between the charger and the grid. A typical on-board battery charger consists of a boost power factor correction (PFC) converter followed by a dc-dc converter. This dissertation focuses on the design, modeling and control of a bidirectional dc-dc converter for conductive battery charging application. In this dissertation, a detailed design procedure is presented for a bidirectional CLLLC-type resonant converter for a battery charging application. This converter is similar to an LLC-type resonant converter with an extra inductor and capacitor in the secondary side. Soft-switching can be ensured in all switches without additional snubber or clamp circuitry. Because of soft-switching in all switches, very high-frequency operation is possible, thus the size of the magnetics and the filter capacitors can be made small. To further reduce the size and cost of the converter, a CLLC-type resonant network with fewer magnetics is derived from the original CLLLC-type resonant network. First, an equivalent model for the bidirectional converter is derived for the steady-state analysis. Then, the design methodology is presented for the CLLLC-type resonant converter. Design of this converter includes determining the transformer turns ratio, design of the magnetizing inductance based on ZVS condition, design of the resonant inductances and capacitances. Then, the CLLC-type resonant network is derived from the CLLLC-type resonant network. To validate the proposed design procedure, a 3.5 kW converter was designed following the guidelines in the proposed methodology. A prototype was built and tested in the lab. Experimental results verified the design procedure presented. The dynamics analysis of any converter is necessary to design the control loop. The bandwidth, phase margin and gain margin of the control loops should be properly designed to guarantee a robust system. The dynamic analysis of the resonant converters have not been extensively studied, with the previous work mainly concentrated on the steady-state models. In this dissertation, the continuous-time large-signal model, the steady-state operating point, and the small-signal model are derived in an analytical closed-form. This model includes both the frequency and the phase-shift control. Simulation and experimental verification of the derived models are presented to validate the presented analysis. A detailed controller design methodology is proposed in this dissertation for the bidirectional CLLLC-type resonant converter for battery charging application. The dynamic characteristics of this converter change significantly as the battery charges or discharges. And, at some operating points, there is a high-Q resonant peaking in the open-loop bode-plot for any transfer functions in this converter. So, if the controller is not properly designed, the closed-loop system might become unstable at some operating points. In this paper, a controller design methodology is proposed that will guarantee a stable operation during the entire operating frequency range in both battery charging mode (BCM) and regeneration mode (RM). To validate the proposed controller design methodology, the output current and voltage loop controllers are designed for a 3.5 kW converter. The step response showed a stable system with good transient performance thus validating the proposed controller design methodology. / Ph. D.

This paper presents a novel controller architecture and speed control design methodology suitable for low cost, low performance switched reluctance motor drives. By utilizing inexpensive components in a simple, compact architecture, a low cost controller is developed which achieves a performance level similar to many high performance controllers. A speed control design methodology is established and analyzed based on the linearized small signal model of the switched reluctance motor. This unique control methodology is simple and provides a starting point for further research into speed/current controller parameter design for switched reluctance motors. The analysis, design and realization of the speed controller are presented. The derivation of the design methodology for speed controlled, switched reluctance motor drives is discussed, along with computer simulations for verification. Experimental results utilizing the proposed architecture and design methodology verify the control design and performance capabilities of the speed controller system. / Master of Science

The transition from fossil fuel-based energy sources involves exploring different sources of energy that can be reliably integrated into the power grid. One such existing resource is the CHPs, which are distributed throughout the US electric grid. The integration of the CHPs into the grid requires technological innovations. One idea is to design an F-CHP converter that would facilitate the CHPs to interconnect seamlessly with the electrical grid. This thesis presents the development and testing of different components of a testbed that would facilitate the testing of the F-CHP converter. It also presents the integration of a PMU and a communication interface for the F-CHP converter. The phasor estimation of the F-CHP PMU has been compared with a commercial PMU and its performance has been validated. / Master of Science / The transition from fossil fuel based energy sources involves exploring different sources of energy that can reliably integrated into the power grid. One such existing resource is the CHPs, that are distributed throughout the US electric grid. The integration of the CHPs into the grid required technological innovations. One idea is to design a power electronics converter that would facilitate the CHPs to connect with the electrical grid. This thesis presents the development and testing of different components of a testbed that would facilitate the testing of the converter. This work also integrates a technology for estimating the voltage and current at the point of interconnection between the converter and the electrical grid.

A key input parameter to governor feedback control and stability protection of generators is the angle of the induced voltage internal to the generator. Current practice is to estimate this value using measurements from the terminals of the generator and mathematical models. This project aims to develop a system that would directly measure the internal angle of the generator using a rotary encoder on the shaft of the machine. This document describes the theory and experimental setup of this proposed system and outlines the test procedure of experimentation. / Master of Science

Traffic signals are one of the vital control elements of traffic management and control systems under purview of Departments of Transportation (DOTs) nationwide. They directly affect mobility, safety, and environmental parameters of the transportation networks. Traffic engineers in DOTs often face pressure for extracting additional benefits from existing signal control equipment, influenced by evident increase in demand and changing traffic patterns. However, they often face difficulties, usually from the maturity of the field equipment, lack of understanding of currently available equipment capabilities, and multitude of market available equipment. Besides issues in everyday operation, the need for improved decision-making process appears during selection and implementation of the future signal-control subsystems. This thesis is focusing on the issues related with the need for extracting additional benefits and improved planning of signal-control equipment deployment. Presented are several methodologies and techniques for modeling and assessing traffic signal controllers and supporting communication infrastructure. Techniques presented in this thesis include Petri Net modeling language, Software-in-the-loop simulation, and Geographical Information Systems. Specific capabilities of listed techniques are coordinated for maximizing their benefits in addressing specific issues. The intended positive effects reflect in enhanced comprehension, numerical representation, and analysis of state-of-the-art signal control subsystems in focus. Frameworks, methodologies, and example cases are presented for each of the specific issues in identified traffic signal subsystems, along with recommendations for further research. / Master of Science

Today's Cyber-Physical Systems (CPS) are typically distributed over several computing nodes communicating by way of shared buses such as Controller Area Network (CAN). Their control performance gets degraded due to variable delays (jitters) incurred by messages on the shared CAN bus due to contention and network overhead. This work presents a novel online delay prediction approach that predicts the message delay at runtime based on real-time traffic information on CAN. It leverages the proposed method to improve control quality, by compensating for the message delay using the Model Predictive Control (MPC) algorithm in designing the controller. By simulating an automotive Cruise Control system and a DC Motor plant in a CAN environment, it goes on to demonstrate that the delay prediction is accurate, and that the MPC design which takes the message delay into consideration, performs considerably better. It also implements the proposed method on an 8-bit 16MHz ATmega328P microcontroller and measures the execution time overhead. The results clearly indicate that the method is computationally feasible for online usage. / Master of Science / In today’s world, most complicated systems such as automobiles employ a decentralized modular architecture with several nodes communicating with each other over a shared medium. The Controller Area Network (CAN) is the most widely accepted standard as far as automobiles are concerned. The performance of such systems gets degraded due to the variable delays (jitters) incurred by messages on the CAN. These delays can be caused by messages of higher importance delaying bus access to the messages of lower importance, or due to other network related issues. This work presents a novel approach that predicts the message delays in real-time based on the traffic information on CAN. This approach leverages the proposed method to improve the control quality by compensating for the message delay using an advanced controller algorithm called Model Predictive Control (MPC). By simulating an automotive Cruise Control system and a DC motor plant in a CAN environment, this work goes on to demonstrate that the delay prediction is accurate, and that the MPC design which takes the message delay into consideration, performs considerably better. It also implements the proposed approach on a low end microcontroller (8bit, 16MHz ATmega328P) and measures the time taken for predicting the delay for each message (execution overhead). The obtained results clearly indicate that the method is computationally feasible for use in a real-time scenario.