Engineering Commons^™

Development Of Northrop-Grumman Mark Viie Training Unit And Wireless Video System For Use In Immersive Environments, Randall Lee Lewis

Theses and Dissertations--Electrical and Computer Engineering

A training unit has been developed that allows NVESD researchers to develop training simulations within virtual environments to enhance infantry skill and awareness. A ground station was developed to house a computer, power system, and video transmission system. This station will allow for a remote operator to wirelessly send a video/audio stream to the handset. The ground station also allows the use of external video and audio inputs to be sent using onboard converters. Different wireless frequencies were evaluated to determine the best for long-range transmission of content. A handset was developed from a carbon fiber prototype shell. The handset …

Proposed Middleware Solution For Resource-Constrained Distributed Embedded Networks, Jason T. Rexroat

Theses and Dissertations--Electrical and Computer Engineering

The explosion in processing power of embedded systems has enabled distributed embedded networks to perform more complicated tasks. Middleware are sets of encapsulations of common and network/operating system-specific functionality into generic, reusable frameworks to manage such distributed networks. This thesis will survey and categorize popular middleware implementations into three adapted layers: host-infrastructure, distribution, and common services. This thesis will then apply a quantitative approach to grading and proposing a single middleware solution from all layers for two target platforms: CubeSats and autonomous unmanned aerial vehicles (UAVs). CubeSats are 10x10x10cm nanosatellites that are popular university-level space missions, and impose power and …

Measurement And Modeling Of Humidity Sensors, Jingbo Tong

Theses and Dissertations--Electrical and Computer Engineering

Humidity measurement has been increasingly important in many industries and process control applications. This thesis research focus mainly on humidity sensor calibration and characterization. The humidity sensor instrumentation is briefly described. The testing infrastructure was designed for sensor data acquisition, in order to compensate the humidity sensor’s temperature coefficient, temperature chambers using Peltier elements are used to achieve easy-controllable stable temperatures. The sensor characterization falls into a multivariate interpolation problem. Neuron networks is tried for non-linear data fitting, but in the circumstance of limited training data, an innovative algorithm was developed to utilize shape preserving polynomials in multiple planes in …

A New Design Of Dc-Dc Converter For Capacitive Deionization Process, Zhiao Li

Theses and Dissertations--Electrical and Computer Engineering

The shortage of clean water has become a significant global problem, and capacitive deionization (CDI) is a technology that can be used to help relieve the problem. A Ćuk converter system that can recover energy from CDI cells is described. This converter transfers energy between two CDI cells when a cell is in its desorption period, allowing energy that would otherwise be lost to be recovered and improving overall system efficiency. In order to control the states of the MOSFET switches in the converter, a self boost charge pump is used. In this way, the microcontroller can control system duty …

Humidity Sensor Circuit Using Real Time Operating System (Freertos) Kernel, Bojie Chen

Theses and Dissertations--Electrical and Computer Engineering

A humidity sensor can be used to measure the moisture content of the environment. The physical change of the sensor expresses as the change of electrical property like capacitance, resistance, voltage, current, frequency, etc. In order to process these analog signals digitally, microprocessor is involved in the measurement. This thesis presents design of a circuit to measure low moisture levels. The 16-bit RISC mixed signal microcontroller MSP430F249 from Texas Instruments will be used. The circuit has good performance at extremely low humidity levels.

Meanwhile, a small real time operating system kernel FreeRTOS, a market leading RTOS from Real Time Engineer …

Multifrequency Averaging In Power Electronic Systems, Fei Pan

Theses and Dissertations--Electrical and Computer Engineering

Power electronic systems have been widely used in the electrical power processing for applications with power levels ranging from less than one watt in battery-operated portable devices to more than megawatts in the converters, inverters and rectifiers of the utility power systems. These systems typically involve the passive elements such as inductors, capacitors, and resistors, the switching electronic components such as IGBTs, MOSFETS, and diodes, and other electronic circuits. Multifrequency averaging is one of the widely used modeling and simulation techniques today for the analysis and design of power electronic systems. This technique is capable of providing the average behavior …

Model Analysis And Predictive Control Of Double Electrode Submerged Arc Welding Process For Fillet Joints With Root Opening, Yi Lu

Theses and Dissertations--Electrical and Computer Engineering

Submerged Arc Welding (SAW) for fillet joints is one of the major applications in the shipbuilding industry. Due to the requirement for the weld size, a sufficient amount of metal must be deposited. In conventional SAW process, the heat input is proportional to the amount of metal melted and is thus determined by the required weld size. To meet this requirement, an excessive amount of heat is applied causing large distortions on the welded structures whose follow-up straightening is highly costly. In order to reduce the needed heat input, Double-Electrode (DE) technology has been practiced creating the Double-Electrode SAW (DE-SAW) …

Machine-Human Cooperative Control Of Welding Process, Weijie Zhang

Theses and Dissertations--Electrical and Computer Engineering

An innovative auxiliary control system is developed to cooperate with an unskilled welder in a manual GTAW in order to obtain a consistent welding performance. In the proposed system, a novel mobile sensing system is developed to non-intrusively monitor a manual GTAW by measuring three-dimensional (3D) weld pool surface. Specifically, a miniature structured-light laser amounted on torch projects a dot matrix pattern on weld pool surface during the process; Reflected by the weld pool surface, the laser pattern is intercepted by and imaged on the helmet glass, and recorded by a compact camera on it. Deformed reflection pattern contains the …

Multi-Domain, Multi-Objective-Optimization-Based Approach To The Design Of Controllers For Power Electronics, Jing Shang

Theses and Dissertations--Electrical and Computer Engineering

Power converter has played a very important role in modern electric power systems. The control of power converters is necessary to achieve high performance. In this study, a dc-dc buck converter is studied. The parameters of a notional proportional-integral controller are to be selected. Genetic algorithms (GAs), which have been widely used to solve multi-objective optimization problems, is used in order to locate appropriate controller design. The control metrics are specified as phase margin in frequency domain and voltage error in time-domain. GAs presented the optimal tradeoffs between these two objectives. Three candidate control designs are studied in simulation and …