<p>Unexpected failures in rotating machinery can result in production downtime, costly repairs and safety concerns. Electric motors are commonly used in rotating machinery and are critical to their operation. Therefore, fault detection and diagnosis of electric motors can play a very important role in increasing their reliability and operational safety. This is especially true for safety critical applications.</p> <p>This research aims to develop a Fault Detection and Diagnosis (FDD) strategy for detecting motor faults at their inception. Two FDD strategies were considered involving wavelets and state estimation. Bearing faults and stator winding faults, which are responsible for the majority of motor failures, are considered. These faults were physically simulated on a Permanent Magnet Brushless DC Motor (PMBLDC). Experimental results demonstrated that the proposed fault detection and diagnosis schemes were very effective in detecting bearing and winding faults in electric motors.</p> / Master of Applied Science (MASc)

<p>This thesis presents the design stages in creating a robotic driving system for performing in-lab driving schedule playback using a chassis dynamometer. This equipment is intended to assist research in improving the power train system in Hybrid Electric Vehicles (HEV). The design stage layout contributes to showing how to effectively breakdown a mechatronics related project into manageable steps. The process includes background research, system requirements, system design and validation. Design stages are further broken up into three subsystems, mechanical, electrical and software.</p> <p>Two actuators control the gas and brake pedals of the test vehicle. An active control system allows the vehicle to follow a speed vs. time driving schedule. The control feedback loop uses two cascading Proportional-Integral (PI) controllers (vehicle speed and pedal position). Feedback signals come from the onboard diagnostics (OBD-II) port. The control software is implemented on a dSPACE MicroAutoBox capable of multiple inputs and outputs including a built in CAN Bus controller to receive messages from the OBD-II port. The control software is implemented in Simulink and provides a modular, maintainable architecture for future development.</p> <p>The system design steps lead to a practical system obtained through a systematic approach. Design documentation will allow for further development of this test system to meet future requirements.</p> / Master of Applied Science (MASc)

<p>The production of a novel micropump based on the synthetic jet principle is investigated both numerically and experimentally. The proposed micropump consists of a synthetic jet actuator driven by a vibrating diaphragm issuing into an inverted T- shaped channel structure forming the inlet/outlet channels of the pump.</p> <p>The software package Ansys is used to perform numerical investigations of the operation of the proposed micropump. Simulations were performed to study the effect of changing the inlet/outlet channel dimensions as well as the operating frequency, amplitude and duty cycle of the excitation signal. Inlet/outlet channel widths ranging from 200 to 800 μm and operating amplitude and frequency of excitation of the 5 mm square membrane driving the synthetic jet actuator ranging from 20 to 60 μm and from 20 to 60 Hz respectively were investigated.</p> <p>Based on the findings of the numerical simulations, a prototype design was chosen and produced. Prototype production using microfabrication techniques as well as micromachining was investigated. The final prototype was micromachined using plexiglass as the working material. An experimental setup was constructed to test the performance of the produced prototype, which allowed for measuring the produced flow rate, pressure head, actuation amplitude and frequency.</p> <p>The findings of the numerical simulations verified the possibility to produce a working micropump with flow rates of up to 1.3 ml/min. Simulation results also showed the dependence of the produced flow rate on both the inlet and outlet channel widths. An increase in the inlet channel width resulted in a gain in the average flow rate through the pump while an increase in the outlet channel width results in a reduction in the flow rate. Increases in either the actuation amplitude or frequency of excitation both resulted in an improvement in the produced flow rate. Changes in the ejection duty cycle, or the ejection time relative to the suction time during an actuation cycle, were found to influence the flow rate produced by the pump. A shorter ejection time produced a higher flow rate from the pump as compared to a longer ejection time. It was also found that changes in dimensions or operating parameters affected the fluctuations in the flow rate through the pump associated with the pulsating nature of the synthetic jet. Experimental investigations confirmed the findings of the numerical simulations in terms of the flow rate and the trends in the dependence of the flow rate on operating parameters. Values of maximum back pressure of up to 500 Pa were also reported experimentally and membrane driving powers of up to 122 μW were calculated numerically.</p> / Doctor of Philosophy (PhD)

The quantity and length of optical fibers required for the Hobby-Eberly Telescope Dark Energy eXperiment (HETDEX) create unique fiber handling challenges. More than 33,000 optical fibers will enable the Hobby-Eberly Telescope (HET) to collect data on at least one million galaxies that are 9 billion to 11 billion light-years away, yielding the largest map of the universe ever produced [1,2]. The design advantages made possible by optical fibers also forms challenges to prevent damage to the fragile fibers that can lead to Focal Ratio Degradation (FRD) [3]. Therefore, a life cycle test must be conducted to study fiber behavior and measure FRD as a function of time. This thesis describes the design and design methodology of an electro-mechanical test apparatus for accelerated life testing of optical fiber assemblies. The design methodology summarizes the development of functional requirements and constraints that drove the design. The test apparatus design utilizes six linear actuators to replicate the movement of the fiber system deployed on HETDEX for over 65,000 accelerated cycles, simulating five years of actual operation. The electro-mechanical test apparatus will provide insight into the effects of load history on the performance of optical fibers which published data has thus far been lacking. Performance of the electro-mechanical test apparatus will be demonstrated through simulation, modeling and calculations. The test results that will be generated from the accelerated life test will be of great interest to designers of robotic fiber handling systems for major telescopes. / text

Roughly 50,000 people are injured in bicycle collisions with motor vehicles each year. The Hank Bicycle Simulator provides a virtual environment to study and reduce this tragic loss by safely investigating the interaction of bicycle riders and traffic, particularly for bicyclists crossing streets. The bicycle simulator design focuses on the bicycle and rider inertia, the predominant dynamic element for riders moving from a stopped position. The Hank Bicycle Simulator’s flywheel provides instantaneous inertial response while a servomotor provides simulated wind resistance to pedaling. This work describes the simulator design and a validation experiment that compares the simulator performance to theoretical predictions. The Hank Bicycle Simulator achieved initial acceleration with less than 0.20% error at realistic rider weights. The observed terminal velocity achieved less than 3.75%, with smaller errors for heavier riders. This allows the rider to cross a street with about a 60 ms time difference between the simulator and a real-life rider pedaling at a constant propulsive force. The Hank Bicycle Simulator was also validated through various physical experiments measuring the system inertia, the time delay of the electrical components, and the overall system performance. Such careful system validation for a mechanical feedback system is relatively rare in simulation research and is unique among previous reports of bicycle simulators.

@font-face { font-family: "TimesNewRoman"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } Teleoperated task execution for hazardous environments is slow and requires highly skilled operators. Attempts to implement telerobotic assists to improve efficiency have been demonstrated in constrained laboratory environments but are not being used in the field because they are not appropriate for use on actual remote systems operating in complex unstructured environments using typical operators. This work describes a methodology for combining select concepts from behavior-based systems with telerobotic tool control in a way that is compatible with existing manipulator architectures used by remote systems typical to operations in hazardous environment. The purpose of the approach is to minimize the task instance modeling in favor of a priori task type models while using sensor information to register the task type model to the task instance. The concept was demonstrated for two tools useful to decontamination & dismantlement type operations—a reciprocating saw and a powered socket tool. The experimental results demonstrated that the approach works to facilitate traded control telerobotic tooling execution by enabling difficult tasks and by limiting tool damage. The role of the tools and tasks as drivers to the telerobotic implementation was better understood in the need for thorough task decomposition and the discovery and examination of the tool process signature. The contributions of this work include: (1) the exploration and evaluation of select features of behavior-based robotics to create a new methodology for integrating telerobotic tool control with positional teleoperation in the execution of complex tool-centric remote tasks, (2) the simplification of task decomposition and the implementation of sensor-based tool control in such a way that eliminates the need for the creation of a task instance model for telerobotic task execution, and (3) the discovery, demonstrated use, and documentation of characteristic tool process signatures that have general value in the investigation of other tool control, tool maintenance, and tool development strategies above and beyond the benefit sustained for the methodology described in this work.

Cell mechanics are directly related to the biological functionality of a cell, and therefore have been extensively studied. Current understanding of the unique relationships associated with mechanical loading conditions and the biological outcomes of a cell is far from complete [1]. The main objective of this thesis work was the design of a device capable of determining mechanical properties including stiffness and Young’s modulus of a biological cell. The device was implemented using micro-electro mechanical systems technology (MEMS), and the cell testing was limited to yeast cells for the purpose of this research. The design consisted of a micro-gripper which performed controlled cell squeezing with a spring of known stiffness. Differential displacements were obtained allowing for the calculation of cell mechanical properties. The incorporation of spatially periodic structures on the moving components of the gripper enabled measurements with 10 nm precision based on discrete Fourier transformation and phase [2].

Micromachined accelerometers have found large attention in recent years due to their low-cost and small size. There are extensive studies with different approaches to implement accelerometers with increased performance for a number of military and industrial applications, such as guidance control of missiles, active suspension control in automobiles, and various consumer electronics devices. This thesis reports the development of various capacitive micromachined accelerometers and various integrated CMOS readout circuits that can be hybrid-connected to accelerometers to implement low-cost accelerometer systems. Various micromachined accelerometer prototypes are designed and optimized with the finite element (FEM) simulation program, COVENTORWARE, considering a simple 3-mask surface micromachining process, where electroplated nickel is used as the structural layer. There are 8 different accelerometer prototypes with a total of 65 different structures that are fabricated and tested. These accelerometer structures occupy areas ranging from 0.2 mm2 to 0.9 mm2 and provide sensitivities in the range of 1-69 fF/g. Various capacitive readout circuits for micromachined accelerometers are designed and fabricated using the AMS 0.8 &micro / m n-well CMOS process, including a single-ended and a fully-differential switched-capacitor readout circuits that can operate in both open-loop and close-loop. Using the same process, a buffer circuit with 2.26fF input capacitance is also implemented to be used with micromachined gyroscopes. A single-ended readout circuit is hybrid connected to a fabricated accelerometer to implement an open-loop accelerometer system, which occupies an area less than 1 cm2 and weighs less than 5 gr. The system operation is verified with various tests, which show that the system has a voltage sensitivity of 15.7 mV/g, a nonlinearity of 0.29 %, a noise floor of 487 Hz &micro / g , and a bias instability of 13.9 mg, while dissipating less than 20 mW power from a 5 V supply. The system presented in this research is the first accelerometer system developed in Turkey, and this research is a part of the study to implement a national inertial measurement unit composed of low-cost micromachined accelerometers and gyroscopes.

Indium tin oxide (ITO) is the most widely used transparent electrode in flexible solar cells because of its high transparency and conductivity. But still, cracking of ITO on PET substrates due to tensile loading is not fully understood and it affects the functionality of the solar cell tremendously as ITO loses its conductivity. Here, we investigate the cracking evolution in ITO/PET exposed to two categories of tests. Monotonous tensile testing is done in order to trace the crack propagation in ITO coating as well as determining a loading range to focus on during our study. Five cycles test is also conducted to check the crack closure effect on the resistance variation of ITO. Analytical model for the damage in ITO layer is implemented using the homogenization concept as in laminated composites for transverse cracking. The homogenization technique is done twice on COMSOL to determine the mechanical and electrical degradation of ITO due to applied loading. Finally, this damage evolution is used for a simulation to predict the degradation of ITO as function in the applied load and correlate this degradation with the resistance variation. Experimental results showed that during unloading, crack closure results in recovery of conductivity and decrease in the overall resistance of the cracked ITO. Also, statistics about the crack spacing showed that the cracking pattern is not perfectly periodical however it has a positively skewed distribution. The higher the applied load, the less the discrepancy in the crack spacing data. It was found that the cracking mechanism of ITO starts with transverse cracking with local delamination at the crack tip unlike the mechanism proposed in the literature of having only cracking pattern without any local delamination. This is the actual mechanism that leads to the high increase in ITO resistance. The analytical code simulates the damage evolution in the ITO layer as function in the applied strain. This will be extended further to correlate the damage to the resistance variation in following studies.

Recent discoveries in geospace science have necessitated the design of compact UV imaging instruments to make space-based observations from multiple vantage points. The miniaturized ultraviolet imager (MUVI) instrument from the Space Sciences Laboratory (SSL) at UC Berkeley is under development to facilitate such discoveries on a wider scale. This thesis documents the design, integration, and characterization of a vacuum compatible manipulator to calibrate the MUVI instrument inside the UV thermal vacuum chamber at SSL. Precision linear and rotation stages were implemented with custom mounting plates to achieve four degrees of freedom. Optical components were installed to imitate the MUVI instrument for testing purposes. A customized PCB was fabricated to control the stages and receive position feedback data. A Graphical User Interface was programmed and utilized to position the manipulator during experimental validation. Field of View sweeps were conducted using visible light and a monochromatic CMOS sensor to track the coordinates of a laser's centroid. An analytical model of the optics assembly was developed and later refined from the experimental results. Using this model, the translation stages successfully compensated for optical misalignments. Analysis of the performance data showed the pointing resolution of the manipulator was less than 1 arcmin, which satisfied the calibration requirement for the MUVI imager.