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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

Simulation and optimization of MEMS actuators and tunable capacitors

Wan, Weijie, 1982- January 2006 (has links)
No description available.
212

Advanced Methods, Materials, and Devices for Microfluidics

White, Celesta E. 26 November 2003 (has links)
Advanced Methods, Materials, and Devices for Microfluidics Celesta E. White 217 Pages Directed by Dr. Clifford L. Henderson Microfluidics is a rapidly growing research area that has the potential to influence a variety of industries from clinical diagnostics to drug discovery. Unlike the microelectronics industry, where the current emphasis is on reducing the size of transistors, the field of microfluidics is focusing on making more complex systems of channels with more sophisticated fluid-handling capabilities, rather than reducing the size of the channels. While lab-on-a-chip devices have shown commercial success in a variety of biological applications such as electrophoretic separations and DNA sequencing, there has not been a significant amount of progress made in other potential impact areas for microfluidics such as clinical diagnostics, portable sensors, and microchemical reactors. These applications can benefit greatly from miniaturization, but advancement in these and many other areas has been limited by the inability or extreme difficulty in fabricating devices with complex fluidic networks interfaced with a variety of active and passive electrical and mechanical components. Several techniques exist for the fabrication of microfluidic devices, but these methods have significant limitations, and alternative fabrication approaches are currently desperately needed. One such method that shows promise for its ability to integrate the desired high levels of functionality utilizes thermally sacrificial materials as place holders. An encapsulating overcoat material provides structural stability and becomes the microchannel walls when the sacrificial material is removed from the channel through thermal decomposition. Disadvantages of this method, however, include numerous processing steps required for sacrificial layer patterning and elevated temperatures needed for the decomposition of initial sacrificial materials. These limitations keep this method from becoming an economical alternative for microfluidic device fabrication. The materials needed for this method to reach its full potential as a valid fabrication technology for m-TAS are not currently available, and it was a major focus of this work to develop and characterize new sacrificial materials, particularly photosensitive polycarbonate systems. In addition to the development of new sacrificial polymers, the framework for a working microfluidic device was developed to show that this concept will indeed provide significant advancements in the development of future generations of microfluidic systems. Finally, novel fabrication methods for microfluidics through combined imprinting and photopatterning of photosensitive sacrificial materials was demonstrated.
213

Analytical modelling and optimization of a thermal convective microfluidic gyroscope

Vosloo, Surika 03 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This thesis deals with the mathematical optimization of the detecting chamber of a thermal convective microfluidic gyroscope and the comparison of several different optimization strategies. An analytical model is developed for the gyroscope and some design considerations are discussed. Sequential approximate optimization strategies are explained and compared to each other by implementing test problems fromthe literature. The optimization problem is formulated from the analytical model and implemented using the different optimization strategies. Results are presented and compared to find the most effective optimization strategy. A sequential approximate optimization algorithm is implemented in MATLAB and tested using the gyroscope design problem and common test problems from the literature. Results and iteration history are compared with an existing FORTRAN implementation. / AFRIKAANSE OPSOMMING: Hierdie tesis handel oor die wiskundige optimering van die deteksiekamer van n termies-konvektiewe mikrovloeier giroskoop en die vergelyking van verskeie optimeringsstrategieë. ’n Analitiese model is opgestel vir die giroskoop en verskeie ontwerpsoorwegings word bespreek. Sekwensiëel benaderde optimeringsstrategieë word bespreek en met mekaar vergelyk, deur dit op toetsprobleme uit die literatuur toe te pas. Die optimeringsprobleem is geformuleer uit die analitiese model en geimplementeer deur gebruik te maak van verskeie optimeringsstrategieë. Resultate word getoon en vergelyk, omdie mees effektiewe optimeringsstrategie te vind. ’n Algoritme vir sekwensiëel benaderde optimeringsprobleme is inMATLAB geimplementeer. Die giroskoop probleem, asook probleme uit die literatuur, is gebruik om resultate en iterasie geskiedenis te vergelyk met ’n bestaande FORTRAN implementasie.
214

Probabilistic modeling of microgrinding wheel topography

Kunz, Jacob Andrew 20 September 2013 (has links)
This work addresses the advanced probabilistic modeling of the stochastic nature of microgrinding in the machining of high-aspect ratio, ceramic micro-features. The heightened sensitivity of such high-fidelity workpieces to excessive grit cutting force drives a need for improved stochastic modeling. Statistical propagation is used to generate a comprehensive analytic probabilistic model for static wheel topography. Numerical simulation and measurement of microgrinding wheels show the model accurately predicts the stochastic nature of the topography when exact wheel specifications are known. Investigation into the statistical scale affects associated microgrinding wheels shows that the decreasing number of abrasives in the wheel increases the relative statistical variability in the wheel topography although variability in the wheel concentration number dominates the source of variance. An in situ microgrinding wheel measurement technique is developed to aid in the calibration of the process model to improve on the inaccuracy caused by wheel specification error. A probabilistic model is generated for straight traverse and infeed microgrinding dynamic wheel topography. Infeed microgrinding was shown to provide a method of measuring individual grit cutting forces with constant undeformed chip thickness within the grind zone. Measurements of the dynamic wheel topography in infeed microgrinding verified the accuracy of the probabilistic model.
215

Desenvolvimento de um micro-transdutor acústico capacitivo. / Development of an acoustic capacitive microtransducer.

Mendonça, Lucas Gonçalves Dias 09 December 2013 (has links)
Neste trabalho é proposto um dispositivo MEMS do tipo micro-transdutor acústico capacitivo, CMUT (sigla em inglês - Capacitive Micromachined Ultrasonic Transducer). Em vez de usar piezoeletricidade, o CMUT tem um array de capacitores, onde cada capacitor possui um eletrodo inferior fixo, uma cavidade e o eletrodo superior composto de uma placa flexível. Quando submetida a uma tensão CC adequada, a placa se deflete se aproximando do eletrodo inferior devido à força eletrostática. Assim a placa fica tensionada podendo vibrar quando excitada por uma tensão CA. Neste caso o CMUT opera como emissor de ondas acústicas. A placa também pode ser excitada por uma onda acústica agindo em sua superfície. Neste caso o dispositivo opera como sensor. Uma das contribuições desse trabalho é o processo de fabricação simplificado com o uso do fotorresiste SU-8 como parte da estrutura do dispositivo. Sua facilidade de processamento e suas propriedades físicas lhe conferem estabilidade e rigidez adequadas para tal fim. Foram realizadas modelagens e simulações analíticas e computacionais do comportamento da placa. Os resultados auxiliaram no melhor entendimento do comportamento do dispositivo sob tensão mecânica devido a uma carga ou uma tensão de polarização. Esses resultados também auxiliaram na definição de parâmetros iniciais do processo de fabricação. Durante o processo de fabricação, foram realizados diversos testes a fim de se encontrar o processo mais adequado à infraestrutura disponível. No processo escolhido, a base do dispositivo é fabricada num substrato de vidro com eletrodos inferiores de alumínio depositados por evaporação. Os pilares são fabricados em SU-8, depositado por spin coatting. A placa é colada posteriormente utilizando-se fotorresiste AZ. O AZ é depositado sobre um pedaço de folha de cobre ou alumínio. As duas partes são colocadas em contato e para promover a colagem é aplicada pressão durante a cura. As amostras foram caracterizadas eletricamente utilizando-se um medidor de impedância RCL. Foram levantadas curvas de impedância, capacitância e ângulo de fase em função da frequência (1 kHz a 1 MHz). Além do sinal CA utilizado pelo instrumento durante a medição foi aplicado um nível CC que variou conforme as dimensões dos protótipos. Também foram levantadas curvas de impedância, capacitância e angulo de fase em função de uma carga mecânica aplicada. Para valores de polarização mais elevados, foram montados circuitos específicos. Estes circuitos são capazes de polarizar o CMUT, aplicar um sinal CA para medição e proteger demais componentes e instrumentos dos aparatos de medição. O dispositivo respondeu bem a aplicação de carga mecânica, excitação por sinal CA e excitação com onda mecânica. Os resultados mostraram que o dispositivo apresenta bom potencial para ser aplicado na análise de fluidos. / This work presents a new process to fabricate an acoustic micro transducer to be used as a microsensor or a microactuator. The acoustic transducers are based on the electrostatic effect and consist on arrays of microfabricated capacitors. Such devices are commonly referred as CMUT, Capacitive Micromachined Ultrasonic Transducer. The bottom electrode (evaporated aluminum) of each capacitor is fixed on the surface of glass substrate, while the top electrode is a thin plate structure of copper or aluminum suspended on a cavity surrounded by posts. Since the top electrode is flexible, it bends toward the bottom electrode when a DC bias is applied. In this way, the top electrode can be forced to vibrate using an AC signal to be used as an acoustic wave emitter. Conversely, an ultrasound receiver is achieved as the measured capacitance changes when the DC biased top electrode moves following an external acoustic wave pressure. An innovation of this work is the use of the photoresist SU-8 to fabricate the post structures surrounding the cavities of the capacitive micro transducers. Its relatively simple processing steps and adequate mechanical properties make the SU-8 a convenient choice as an inexpensive structural material. The bottom part of the device is prepared on a glass substrate using an aluminum layer evaporated and etched to form the bottom electrodes. Then, SU-8 is spin coated, baked and etched adequately to form the posts surrounding the cavities. The top part is prepared by simply spinning an AZ-type photoresist on aluminum or copper plate. Finally, both halves are bonded under pressure on a hot plate. Several modeling and simulation analyses were performed in order to estimate the working performance of the micro transducers. The results of simulations helped to define the initial parameters and materials for the fabrication process. Samples submitted to a DC bias were initially characterized using an RCL meter in order to infer impedance, capacitance and phase angle behavior as a function of frequency (from 1 kHz to 1 MHz). Protection circuits were used in order to test CMUTs with high DC bias. These circuits allow to apply high DC bias, and an AC signal while other measuring equipments are protected. The device responded to application of mechanical loading, excitation by an AC signal and excitation by mechanical wave as well. The results showed that the device has good potential to be applied to the analysis of fluids.
216

An attitude compensation technique for a MEMS motion sensor based digital writing instrument.

January 2006 (has links)
Luo Yilun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 87-91). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- Organization --- p.3 / Chapter 2. --- Architecture of MAG-μIMU --- p.5 / Chapter 2.1. --- Hardware for Attitude Filter --- p.5 / Chapter 2.2. --- Handwriting Recording for a Digital Writing Instrument --- p.7 / Chapter 3. --- Inertial Tracking for Handwriting --- p.9 / Chapter 3.1. --- Spatial Descriptions and Transformations --- p.9 / Chapter 3.1.1. --- Vector Description and Position of a Frame --- p.9 / Chapter 3.1.2. --- Coordinate Transformation and Orientation of a Frame --- p.10 / Chapter 3.1.3. --- Kinematics for Digital Writing Instruments --- p.12 / Chapter 3.1.4. --- Vector Rotation --- p.16 / Chapter 3.2. --- Euler Angles for Rotation in Space --- p.17 / Chapter 3.3. --- Euler Angles Attitude Kinematics --- p.19 / Chapter 3.4. --- Singular Problem --- p.19 / Chapter 4. --- Attitude in Quaternion --- p.22 / Chapter 4.1. --- Quaternion Operations --- p.22 / Chapter 4.1.1. --- Quaternion Conjugate --- p.23 / Chapter 4.1.2. --- Quaternion Norm --- p.24 / Chapter 4.1.3. --- Quaternion Inverse --- p.24 / Chapter 4.2. --- Orientation Description in Quaternion --- p.24 / Chapter 4.3. --- Attitude Kinematics in Quaternion --- p.25 / Chapter 5. --- Kalman Filter --- p.27 / Chapter 5.1. --- Time Update --- p.28 / Chapter 5.2. --- Measurement Update --- p.29 / Chapter 5.2.1. --- Maximum a Posterior Probability --- p.29 / Chapter 5.2.2. --- Batch Least-Square Estimation --- p.31 / Chapter 5.2.3. --- Measurement Update in Kalman Filter --- p.34 / Chapter 5.3. --- Kalman Filter Summary --- p.36 / Chapter 6. --- Extended Kalman Filter --- p.38 / Chapter 7. --- Attitude Extended Kalman Filter --- p.41 / Chapter 7.1. --- Time Update Model --- p.41 / Chapter 7.1.1. --- Attitude Strapdown Theory for a Quaternion --- p.41 / Chapter 7.1.2. --- Error Model for Time Update --- p.42 / Chapter 7.2. --- Measurement Update Model --- p.43 / Chapter 7.2.1. --- Error Model for the Measurement Update --- p.45 / Chapter 7.3. --- Summary --- p.46 / Chapter 8. --- Experiment Results --- p.47 / Chapter 8.1. --- Experiment for Attitude EKF based on MAG-μIMU --- p.47 / Chapter 8.1.1. --- Simulation Test --- p.48 / Chapter 8.1.2. --- Experiment Test --- p.49 / Chapter 8.2. --- Writing Application based on Attitude EKF Compensation --- p.52 / Chapter 8.2.1. --- Stroke Segment Kalman Filter --- p.54 / Chapter 8.2.2. --- Zero Velocity Compensation --- p.58 / Chapter 8.2.3. --- Complementary Attitude EKF for Writing Experiment --- p.60 / Chapter 9. --- Future Work --- p.73 / Chapter 9.1. --- Unscented Kalman Filter --- p.73 / Chapter 9.1.1. --- Least-square Estimator Structure --- p.73 / Chapter 9.1.2. --- Unscented Transform --- p.74 / Chapter 9.1.3. --- Unscented Kalman Filter --- p.76 / Chapter 9.2. --- Experiment Result --- p.81 / Chapter 10. --- Conclusion --- p.85 / Chapter 10.1. --- Attitude Extended Kalman Filter --- p.85 / Chapter 10.2. --- Complementary Attitude EKF --- p.85 / Chapter 10.3. --- Unscented Kalman Filter --- p.86 / Chapter 10.4. --- Future Work --- p.86 / Bibliography --- p.87 / Appendix A --- p.92
217

Design and experimental study on miniature vapor compression refrigeration systems. / CUHK electronic theses & dissertations collection

January 2012 (has links)
近年來微型製冷系統有許多應用。例如,電子器件的冷却是研製更快速、更小型和更可靠的芯片的重要課題, 隨著電子芯片功耗的增加,散熱量不断增長,傳統的被動式散熱方法已經過時,新的主動式散熱方法成爲必須。又例如微型個人冷卻系統可用於救火等各種惡劣環境。与其它製冷方法相比,蒸氣壓縮製冷技術是最有潜力的方法。 / 本文闡述了两种微型蒸氣壓縮製冷系統的研製工作:一是電子冷却系统,一是個人热舒适系统。研究主要包括以下幾個方面: / 1) 微型蒸氣壓縮製冷系統的熱力學分析。對系統在不同工作條件下(包括壓縮機效率、環境溫度等)的性能進行了分析。对換熱器的設計也作了详述。 / 2) 微型蒸氣壓縮製冷系統的熵分析。通過分析發現,壓縮機和系統漏熱造成的熵是產生系統不可逆性的主要因素,因此高效的壓縮機和降低系統漏熱是提高微型蒸氣壓縮製冷系統性能的關鍵所在。 / 3) 實驗系统的詳細介紹。一共做了两套微型蒸氣壓縮製冷系統,一为電子冷卻系統和一为個人冷卻系統。爲了縮小微型蒸氣壓縮製冷系統的尺寸,系統的元件必須小型化。系統的壓縮機是在市場上直接购買的,但是換熱器包括冷板蒸發器、管翅式蒸發器和微通道冷凝器都是特別設計和製造的。實驗裝置建成可以方便的改變工作條件,諸如壓縮機轉速、製冷劑充灌量、毛細管長度、換熱器面積等。 / 4) 對電子冷卻系統和個人冷卻系統分別進行了實驗。對於電子散熱系統來,當發熱管的功率為200瓦時,冷板溫度可以控制在大約60攝氏度。系統的熱力學完善度在0.23到0.31,而壓縮機的效率介乎40%至65%。對個人冷卻系統來,系統製冷量可達321瓦,其性能係數達到4.59。系統的熱力學完善度為0.21 ~ 0.27。 兩种系統的熱力學完善度都與當前家用製冷系统的熱力學完善度相似。相信不久的将来会有不少应用。 / Micro refrigeration systems are being increasingly used nowadays. One example is electronic cooling. With the rapid advancement of chips, traditional passive heat dissipation techniques are becoming obsolete and hence, new active cooling techniques become necessary. The other example is the personal thermal comfort system demanded by people working in the hazardous environment, such as fire fighting. Among various cooling methods, Vapor Compression Refrigeration (VCR) is the most promising method. According literatures, however, few miniature refrigeration systems are available. / This thesis presents two Miniature Vapor Compression Refrigeration (MVCR) systems, one for electronics cooling and the other for personal thermal comfort. In particularly, following aspects are focused: / 1) Thermodynamic analysis. The thermodynamic models of the systems are developed and the performances are studied under various working conditions including compressor efficiencies, ambient temperature and so on. / 2) Entropy analysis. It is found that entropy of the compressor and the heat leakage play crucial roles. High efficient compressor and the heat leakage minimization are very important. / 3) Prototype building. Two prototypes are built: one for electronics cooling and the other for personal thermal comfort. The miniature compressors are purchased from market. The heat exchangers, including the cold pate, tube-fin evaporator and micro channel condenser, are custom designed and made. / 4) Experiment testing. The two prototypes are tested under various working conditions such as compressor speed, refrigerant charge and capillary tube length. For the electronics cooling system, the cold plate temperature could be maintained at about 60 ºC under the 200 W heater power input. The second-law efficiency of the system varies from 0.23 to 0.31; and the compressor efficiency is between 40% ~ 65%. For the personal thermal comfort system, its capacity could reach 321 W with 100 g refrigerant charge, 1200 mm capillary tube length, and the compressor speed of 4503 rpm. The COP is 4.59 and the second-law efficiency is between 0.21 ~ 0.27. The performances of the two systems are comparable to that of the current domestic refrigeration systems. Therefore, it is expected that they will find some practical applications in the near future. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wu, Zhihui. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 99-110). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract --- p.I / Acknowledgement --- p.IV / List of Tables --- p.VIII / List of Figures --- p.IX / Nomenclature --- p.XII / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Backgound --- p.1 / Chapter 1.2 --- Thesis Outline --- p.5 / Chapter Chapter 2 --- Literature Review --- p.6 / Chapter 2.1 --- History of Refrigeration --- p.6 / Chapter 2.2 --- Availabe Refrigeration Methods --- p.7 / Chapter 2.2.1 --- Heat pipe and vapor chamber --- p.9 / Chapter 2.2.2 --- Thermoelectric cooler --- p.10 / Chapter 2.2.3 --- Stirling refrigerator --- p.10 / Chapter 2.2.4 --- Pulse tube refrigerator --- p.11 / Chapter 2.2.5 --- Absorption refrigerator --- p.12 / Chapter 2.3 --- Vapor Compression Refrigeration System --- p.14 / Chapter 2.3.1 --- Development of the miniature refrigeration system --- p.15 / Chapter 2.3.2 --- Development of the miniature compressors --- p.20 / Chapter 2.3.3 --- Development of the micro heat exchangers --- p.24 / Chapter 2.3.4 --- Applications --- p.28 / Chapter Chapter 3 --- System Analsysis and Components Design --- p.29 / Chapter 3.1 --- A Brief Review of a Typical VCR System --- p.29 / Chapter 3.1.1 --- Refrigerant comparison --- p.33 / Chapter 3.1.2 --- Effect of the compressor efficiency --- p.34 / Chapter 3.1.3 --- Effect of the ambient temperature --- p.35 / Chapter 3.1.4 --- Effect of the evaporator temperature --- p.36 / Chapter 3.2 --- Analysis on Entropy Generation of a MVCR System --- p.37 / Chapter 3.2.1 --- Derivation of coefficient of performance --- p.38 / Chapter 3.2.2 --- Entropy generation calculation for a MVCR system --- p.39 / Chapter 3.3 --- System Design --- p.46 / Chapter 3.3.1 --- System Configuration --- p.46 / Chapter 3.3.2 --- Heat Exchanger Design --- p.47 / Chapter 3.3.2.1 --- Condenser design --- p.48 / Chapter 3.3.2.2 --- Cold plate design --- p.50 / Chapter 3.3.2.3 --- Tube-fin evaporator design --- p.51 / Chapter Chapter 4 --- The MVCR System for Electronics Cooling --- p.55 / Chapter 4.1 --- Experimental Setup --- p.55 / Chapter 4.1.1 --- Components --- p.55 / Chapter 4.1.2 --- Instrumentation --- p.61 / Chapter 4.1.3 --- Testing plans --- p.63 / Chapter 4.1.4 --- Data reduction --- p.64 / Chapter 4.1.5 --- Uncertainty analysis --- p.67 / Chapter 4.2 --- Results and Discussion --- p.68 / Chapter 4.2.1 --- Effect of the compressor speed --- p.68 / Chapter 4.2.2 --- Effect of the refrigerant charge --- p.70 / Chapter 4.2.3 --- Effect of the capillary tube length --- p.71 / Chapter 4.2.4 --- Cold plate temperature comparison --- p.72 / Chapter 4.2.5 --- Location of the Cartridge heater --- p.76 / Chapter 4.2.6 --- System efficiency --- p.78 / Chapter 4.2.7 --- Thermal resistance --- p.81 / Chapter 4.3 --- Summary --- p.83 / Chapter Chapter 5 --- The MVCR System for Personal Cooling --- p.85 / Chapter 5.1 --- Experimental Setup --- p.85 / Chapter 5.2 --- Results and Discussions --- p.87 / Chapter 5.2.1 --- Effect of the compressor speed --- p.87 / Chapter 5.2.2 --- Effect of the refrigerant charge --- p.88 / Chapter 5.2.3 --- Effect of the capillary tube length --- p.89 / Chapter 5.2.4 --- Effect of the evaporator area --- p.90 / Chapter 5.2.5 --- Effect of the evaporator fan speed --- p.91 / Chapter 5.2.6 --- System efficiency --- p.92 / Chapter 5.3 --- Summary --- p.94 / Chapter Chapter 6 --- Conclusions and Future Work --- p.96 / Chapter 6.1 --- Conclusions --- p.96 / Chapter 6.2 --- Future Work --- p.98 / Bibliography --- p.99
218

Milli-meter-scale turning centre: theory and implementation.

January 2007 (has links)
Chan, Ngai Shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 67-70). / Abstracts in English and Chinese. / Abstract --- p.I / 摘要 --- p.III / List of Figures --- p.VI / List of Tables --- p.VIII / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background Information --- p.2 / Chapter 1.1.1 --- Project Background --- p.2 / Chapter 1.1.2 --- Literature Review --- p.4 / Chapter 1.1.3 --- Background on Gear Hobbing --- p.10 / Chapter 1.1.4 --- Traditional gear hobbing machines --- p.12 / Chapter 2 --- Design and Testing of the MMT system --- p.15 / Chapter 2.1 --- Specifications of the MMT system --- p.16 / Chapter 2.1.1 --- Overall Configuration --- p.18 / Chapter 2.1.2 --- Linear Actuation --- p.18 / Chapter 2.1.3 --- Main Spindle Assembly --- p.19 / Chapter 2.1.4 --- Tool Plate Assembly --- p.20 / Chapter 2.1.5 --- Motion Control --- p.22 / Chapter 2.2 --- Main Features --- p.24 / Chapter 2.2.1 --- Mechanically Decoupled Gear Hobbing --- p.24 / Chapter 2.2.2 --- Single Setup for Non-planar Gears --- p.26 / Chapter 2.2.3 --- Quality Assurance by Computer Simulation --- p.27 / Chapter 2.3 --- Turning Test --- p.28 / Chapter 2.3.1 --- Experiment Results --- p.29 / Chapter 2.3.2 --- Tornos' Performance --- p.30 / Chapter 2.3.3 --- Estimation of Cutting Force and Workpiece Deflection --- p.32 / Chapter 2.4 --- Synchronization Test --- p.33 / Chapter 2.4.1 --- Experimental Results --- p.34 / Chapter 2.5 --- Gear Hobbing Test --- p.36 / Chapter 3 --- Diagnostic Tool: Gear Hobbing Simulation --- p.40 / Chapter 3.1 --- Simulation Model --- p.41 / Chapter 3.2 --- Simulations with Process Defects --- p.44 / Chapter 3.2.1 --- Asynchronous motion between tool and workpiece spindle --- p.44 / Chapter 3.2.2 --- Pitch error of the cutter hob --- p.45 / Chapter 3.2.3 --- Tool spindle run-out error --- p.47 / Chapter 3.2.4 --- Combination of process defects --- p.49 / Chapter 3.3 --- Experiment Validation --- p.50 / Chapter 4 --- Technical know-hows --- p.55 / Chapter 4.1 --- Premature Part Break-off --- p.55 / Chapter 4.2 --- Tool Alignment and Centering --- p.58 / Chapter 4.2.1 --- Two-turns Aligning Algorithm --- p.59 / Chapter 5 --- Conclusion and Future Work --- p.63 / References --- p.67 / Publication Record --- p.71 / Appendix --- p.72
219

Position determination of mobile unit based on inertial navigation system.

January 2008 (has links)
Yip, Wai Lee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 119-124). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.ii / Acknowledgement --- p.iii / Table of Content --- p.iv / List of Figure --- p.vi / List of table --- p.viii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Background information --- p.2 / Chapter 1.2.1 --- Overview of positioning technologies --- p.2 / Chapter 1.2.2 --- Comparison between different positioning systems --- p.7 / Chapter 1.2.3 --- Recent works related to INS --- p.9 / Chapter 1.3 --- Objective --- p.11 / Chapter 1.4 --- Organization of thesis --- p.11 / Chapter Chapter 2 --- Literature Study --- p.13 / Chapter 2.1 --- Introduction to INS --- p.13 / Chapter 2.1.1 --- Coordinate Frames --- p.13 / Chapter 2.1.2 --- Gimbaled INS --- p.16 / Chapter 2.1.3 --- Strapdown INS --- p.17 / Chapter 2.1.4 --- Conventional algorithm of strapdown INS --- p.17 / Chapter 2.2 --- Inertial sensors --- p.19 / Chapter 2.2.1 --- Gyroscope --- p.19 / Chapter 2.2.2 --- Accelerometer --- p.20 / Chapter 2.3 --- Previous works --- p.22 / Chapter 2.4 --- GF-INS --- p.23 / Chapter 2.5 --- Summary --- p.25 / Chapter Chapter 3 --- Performance of MEMS accelerometer in position determination --- p.27 / Chapter 3.1 --- Basic principle --- p.27 / Chapter 3.2 --- Numeric integration --- p.28 / Chapter 3.3 --- Experimental setup --- p.30 / Chapter 3.3.1 --- MEMS Accelerometer --- p.30 / Chapter 3.3.2 --- Microcontroller --- p.32 / Chapter 3.3.3 --- System architecture --- p.33 / Chapter 3.3.4 --- Testing platform --- p.34 / Chapter 3.4 --- Initial calibration and filtering --- p.37 / Chapter 3.4.1 --- Convert ADC reading to acceleration --- p.37 / Chapter 3.4.2 --- Identify configuration error --- p.38 / Chapter 3.4.3 --- Implement low pass filter --- p.39 / Chapter 3.5 --- Experimental results --- p.40 / Chapter 3.5.1 --- Results --- p.40 / Chapter 3.5.2 --- Discussion --- p.43 / Chapter 3.6 --- Summary --- p.45 / Chapter Chapter 4 --- Performance Improvement --- p.46 / Chapter 4.1 --- Fuzzy logic based steady state detector --- p.46 / Chapter 4.1.1 --- Principle --- p.46 / Chapter 4.1.2 --- Experimental result --- p.48 / Chapter 4.2 --- Kalman filtering --- p.50 / Chapter 4.2.1 --- Discrete Kalman filter --- p.50 / Chapter 4.2.2 --- Combine with fuzzy logic based steady state detector --- p.52 / Chapter 4.2.3 --- Experimental results --- p.54 / Chapter 4.3 --- Summary --- p.58 / Chapter Chapter 5 --- Construction of GF-INS --- p.59 / Chapter 5.1 --- Principle of GF-INS --- p.59 / Chapter 5.1.1 --- Algorithm --- p.59 / Chapter 5.1.2 --- Comparing error of GF-INS and conventional INS --- p.66 / Chapter 5.1.3 --- Simulation study --- p.67 / Chapter 5.2 --- Experimental setup --- p.73 / Chapter 5.3 --- Experimental Results --- p.75 / Chapter 5.4 --- Summary --- p.81 / Chapter Chapter 6 --- Improvement on the GF-INS --- p.82 / Chapter 6.1 --- Configuration error compensation --- p.82 / Chapter 6.1.1 --- "Identify bias, scale factor and sensing direction error" --- p.83 / Chapter 6.1.2 --- Identify position error --- p.86 / Chapter 6.1.3 --- Compensator design --- p.89 / Chapter 6.1.4 --- Simulation --- p.91 / Chapter 6.2 --- Fuzzy rule based motion state detector --- p.97 / Chapter 6.2.1 --- Relation of data in different motions --- p.97 / Chapter 6.2.2 --- Fuzzy system --- p.99 / Chapter 6.2.3 --- Membership function training with gradient descent --- p.101 / Chapter 6.3 --- Experimental results and discussion --- p.104 / Chapter 6.3.1 --- Configuration errors --- p.104 / Chapter 6.3.2 --- Compensator --- p.106 / Chapter 6.3.3 --- Fuzzy rule based motion state detector --- p.107 / Chapter 6.3.4 --- Comparing the performance of both methods --- p.110 / Chapter 6.3.5 --- Comparing GF-INS and one dimensional INS --- p.112 / Chapter 6.3.6 --- Discussion --- p.113 / Chapter 6.4 --- Summary --- p.115 / Chapter Chapter 7 --- Conclusions and Future works --- p.116 / Reference --- p.119
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Development of 3-D Printed Hybrid Packaging for GaAs-MEMS Oscillators based on Piezoelectrically-Transduced ZnO-on-SOI Micromechanical Resonators

Lan, Di 19 June 2018 (has links)
Prior research focused on CMOS-MEMS integrated oscillator has been done using various foundry compatible integration techniques. In order to compensate the integration compatibility, MEMS resonators built on standard CMOS foundry process could not take full advantage of highest achievable quality factor on chip. System-in-package (SiP) and system-on-chip (SoC) is becoming the next generation of electronic packaging due to the need of multi-functional devices and multi-sensor systems, thus wafer level hybrid integration becomes the key to enable the full assembly of dissimilar devices. In this way, every active circuit and passive component can be individually optimized, so do the MEMS resonators and sustaining amplifier circuits. In this dissertation, GaAs-MEMS integrated oscillator in a hybrid packaging has been fully explored as an important functional block in the RF transceiver systems. This dissertation first presents design, micro-fabrication, simulation, testing and modeling of ZnO piezoelectrically-transduced MEMS resonators. A newly designed rectangular plate with curved resonator body fabricated in-house exhibits a very high Q of more 6,000 in the air for its width-extensional mode resonance at 166 MHz. In addition, a rectangular plate resonator with multiple Phononic Crystal (PC) strip tethers shows low insertion loss of -11.5 dB at 473.9 MHz with a Q of 2722.5 in the air. An oscillator technology with high-Q MEMS resonator as its tank circuit is presented to validate its key functionality as a stable frequency reference across a wide spectrum of frequencies. Particularly, a piezoelectrically-transduced width-extensional mode MEMS resonator is strategically designed to operate at two distinct layout-defined mechanical modal frequencies (259.5MHz and 436.7MHz). These devices were characterized and modeled by an extracted equivalent LCR circuit to facilitate the design of the oscillator using a standard circuit simulator. MEMS resonators have been integrated with the sustaining amplifier circuit at PCB level using wire-bonding technique and coaxial connectors. As shown by the time-domain measurements and frequency-domain measurements, these oscillators are capable of selectively locking into the resonance frequency of the tank circuit and generating a stable sinusoidal waveform. Meanwhile, the phase noise performance is rigorously investigated within a few oscillator designs. At last, 3-D printed hybrid packaging using additive manufacturing and laser machining technique has been developed for integrating a MEMS resonator on a silicon-on-insulator (SOI) substrate and a GaAs sustaining amplifier. Fabrication process and fundamental characterization of this hybrid packaging has been demonstrated. On-wafer probe measurements of a 50 Ω microstrip line on ABS substrate exhibit its insertion loss of 0.028 dB/mm at 5 GHz, 0.187 dB/mm at 20 GHz and 0.512 dB/mm at 30 GHz, and show satisfactory input and output return loss with the 3-D printed package. Parylene N is also experimentally coated on the package for improving water resistance as a form of hermetic packaging.

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