Thesis (Ph. D.)--State University of New York at Binghamton, Department of Mechanical Engineering, 2007. / Includes bibliographical references (leaves 177-179).

University of Macau / Faculty of Science and Technology / Department of Electromechanical Engineering

University of Macau / Faculty of Science and Technology / Department of Electromechanical Engineering

This thesis presents the theoretical analysis and experiment results of MEMS sensors designed for the application of low frequency vibration sensing. Each sensor consists of a proof mass connected to a folded beam micro-flexure, with an attached capacitive comb drive for displacement sensing. Three comb drive arrangements are evaluated, the transverse, lateral, and tri-plate differential. The sensors are fabricated using the well developed foundry processes of PolyMUMPS and SoiMUMPS. In addition, a capacitance to voltage readout circuit is fabricated using discrete components. Static tests, evaluating the capacitance to displacement relation, are conducted on a six degree of freedom robotic manipulator, and dynamic tests evaluating the sensor response to sinusoidal excitations are conducted on a vibrating beam. The end use of the sensor involves real-time vibration monitoring of automobile mechanical systems, such as power seats, windshield wipers, mirrors, trunks, and windows, allowing for early detection of mechanical faults before catastrophic failure.

This thesis presents the theoretical analysis and experiment results of MEMS sensors designed for the application of low frequency vibration sensing. Each sensor consists of a proof mass connected to a folded beam micro-flexure, with an attached capacitive comb drive for displacement sensing. Three comb drive arrangements are evaluated, the transverse, lateral, and tri-plate differential. The sensors are fabricated using the well developed foundry processes of PolyMUMPS and SoiMUMPS. In addition, a capacitance to voltage readout circuit is fabricated using discrete components. Static tests, evaluating the capacitance to displacement relation, are conducted on a six degree of freedom robotic manipulator, and dynamic tests evaluating the sensor response to sinusoidal excitations are conducted on a vibrating beam. The end use of the sensor involves real-time vibration monitoring of automobile mechanical systems, such as power seats, windshield wipers, mirrors, trunks, and windows, allowing for early detection of mechanical faults before catastrophic failure.

Microelectromechanical System (MEMS) technology is advancing rapidly. Gyroscopes, accelerometers and magnetometers, also referred to as an Inertial Measurement Unit (IMU), has traditionally been associated with aerospace and industrial robotics but is now within every smart phone. The proliferation of these low-cost devices has facilitated countless new applications with many more still unrealised. This dissertation presents work towards this end. A significant contribution of this work was the development of novel Attitude and Heading Reference System (AHRS) algorithms that fuse together sensor data from an IMU to provide an absolute measurement of orientation relative to the Earth. The novel work presented on non-gyro IMU s demonstrated the potential practical benefits of such kinematically redundant sensor arrays. Low-cost MEMS can only be fully utilised if they are combined with a calibration solution to provide precise measurements with a determined accuracy. This dissertation presents a comprehensive calibration solution to the specific requirements of these sensors based on extensive characterisations investigations. The calibration solutions enable sensors costing <10 United States Dollar (USD) to achieve a static pitch/roll accuracy of <10 and a static heading accuracy of <2°. This performance is equivalent to commercial 1M Us costing up to 3000 USD. The AHRS algorithm and sensor calibration works were brought together in the development of three IMU hardware platforms. To date, >500 have been sold and the open-source associated algorithm downloaded> 10,000 times. Each platform addressed a specific design need and together these facilitated a wide range of new applications; demonstrated by the numerous scientific publications that resulted from collaborative projects and user projects.

Micro-electro-mechanical Systems (MEMS) technology has revolutionized the micro/nano world by making micro/nano devices feasible. These devices allow more exploration and understanding of the micro/nano world. In this dissertation, we will discuss the measurement of wall shear stress in an integrated microfluidic system built by MEMS technology. Specifically, carbon nanotubes (CNTs) were used as the sensing element for gas-flow shear stress measurement in this work. CNTs have already been proven to have an excellent sensing response to temperature, pressure, and alcohol vapour. Based on the thermal sensing response of CNTs, the sensor was designed to operate using convective heat transfer principles in fluid flow. Dielectrophretic manipulation was used to batch fabricate CNTs on a PMMA substrate. The CNT sensor was then integrated into a PMMA microchannel, which was fabricated by a rapid prototyping technique using moulding/hot-embossing processes. The sensor responded to impinging flow as well as gas-flow shear stress. The sensor activation power was found to be linearly related to the 1/3 exponential power of the wall shear stress. With the measurements of an array of sensors, the flow profile of a microchannel with various types of flow could be studied. Compared with the conventional polysilicon sensor, the CNT sensor has the advantage of small dimensions, i.e. a greater spatial resolution for fluidic measurements, and low power consumption, i.e. it consumes &sim;1,000 times less power than polysilicon sensors. Therefore, CNT sensors have a great potential to serve as an alternative to silicon-based sensors. / Chow, Wing Yin Winnie. / Adviser: Wen J. Li. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3743. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 105-110). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Kwok, Yiu-fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 87-89). / Abstracts in English and Chinese. / ABSTRACT --- p.I / ACKNOWLEDGMENTS --- p.II / TABLE OF CONTENT --- p.III / LIST OF FIGURES --- p.V / Chapter 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Motivation of this project --- p.1 / Chapter 1.3 --- Organization --- p.2 / Chapter 2 --- LITERATURE SURVEY --- p.3 / Chapter 2.1 --- Ionic Conducting Polymer Film (ICPF) --- p.3 / Chapter 2.2 --- Electroactive Polymer (EAP) --- p.4 / Chapter 2.3 --- Micro Active Guide Wire Catheter System --- p.5 / Chapter 2.4 --- Space Application - Dust Wiper --- p.6 / Chapter 2.5 --- Micro gripper --- p.8 / Chapter 2.6 --- Summary of literature survey --- p.14 / Chapter 3 --- METAL-POLYMER COMPOSITIONS --- p.15 / Chapter 3.1 --- Introduction --- p.15 / Chapter 3.2 --- Perfluorosulfonic acid polymer (Nafion) --- p.15 / Chapter 3.3 --- Working principle of ICPF --- p.19 / Chapter 3.4 --- Different types of composition --- p.21 / Chapter 3.4.1 --- Chromium-Gold-polymer composite --- p.23 / Chapter 3.4.2 --- Platinum-Gold-polymer composite --- p.25 / Chapter 3.4.3 --- Silver-polymer composite --- p.27 / Chapter 3.4.4 --- Silver/Copper-gold polymer composite --- p.27 / Chapter 3.4.5 --- Gold-polymer composite --- p.28 / Chapter 4 --- ICPF FABRICATION --- p.30 / Chapter 4.1 --- Introduction --- p.30 / Chapter 4.2 --- ICPF fabrication process --- p.31 / Chapter 4.3 --- Surface pre-treatment --- p.33 / Chapter 4.4 --- Gold thin film deposition (Evaporation) --- p.34 / Chapter 4.4.1. --- Filament evaporation --- p.35 / Chapter 4.4.2 --- Electronic-beam evaporation --- p.39 / Chapter 4.4.3 --- Structural analysis of evaporation --- p.40 / Chapter 4.5 --- Chemical electroplating --- p.42 / Chapter 4.5.1. --- Deposition rate calibration --- p.44 / Chapter 5 --- DESIGN AND PACKAGE --- p.46 / Chapter 6 --- LASER MICROMACHINING --- p.49 / Chapter 6.1 --- Introduction to Laser micromachining --- p.49 / Chapter 6.2 --- C02 laser --- p.50 / Chapter 6.3 --- Nd:YAG Laser --- p.51 / Chapter 6.4 --- Laser micromachining of ICPF actuator --- p.52 / Chapter 7 --- EXPERIMENTAL RESULTS AND ANALYSIS --- p.61 / Chapter 7.1 --- Introduction --- p.61 / Chapter 7.2 --- Measurement setup --- p.62 / Chapter 7.3 --- Width test --- p.68 / Chapter 7.4 --- Length test --- p.73 / Chapter 7.5 --- Voltage test --- p.76 / Chapter 8 --- MICRO GRIPPER ACTUATION --- p.79 / Chapter 8.1 --- Development of micro gripper --- p.79 / Chapter 8.2 --- Micro gripper --- p.80 / Chapter 9 --- CONCLUSION --- p.82 / Chapter 10 --- APPENDIX --- p.83 / Chapter 10.1 --- Procedures in using E-beam evaporator --- p.83 / Chapter 10.2 --- Procedures in using Thermo couple evaporator --- p.85 / Chapter 11 --- REFERENCE --- p.87

Ho Chi-hong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 50-51). / Abstracts in English and Chinese. / Chapter CHAPTER ONE: --- INTRODUCTION --- p.1 / Introduction --- p.1 / Motivation of the Problem --- p.1 / Organization of this Thesis --- p.2 / Chapter CHAPTER TWO: --- LITERATURE SURVEY --- p.3 / Introduction --- p.3 / Electrorheological Fluid --- p.3 / Magnetorheological Fluid --- p.4 / Ferrofluid --- p.4 / "Comparison Amount ER, MR and Ferrofluid" --- p.5 / Chapter CHAPTER THREE: --- THEORETICAL ANALYSIS OF MR FLUIDS FOR MICRO DEVICES --- p.8 / Introduction --- p.8 / Minimal Volume --- p.8 / Magnetic Field Requirement --- p.10 / Particle Size --- p.14 / Chapter CHAPTER FOUR: --- PROCESSING TECHNOLOGY --- p.15 / Introduction --- p.15 / Processing Technology --- p.15 / Chapter CHAPTER FIVE: --- MR FLUID PILLARS --- p.18 / Introduction --- p.18 / Description of Experimental Setup --- p.18 / Finite element Analysis of the Experiment --- p.23 / Alignment Theory of MR Fluid Pillar --- p.29 / Discussion of Fluid Surface Tension --- p.36 / Chapter CHAPTER SIX: --- APPLICATIONS --- p.39 / Introduction --- p.39 / MR Fluid Actuator --- p.39 / Micro Brake --- p.45 / Micro Brake --- p.46 / Micro Clutches --- p.46 / Damper for Micro-Robot System --- p.46 / Chapter CHAPTER SEVEN: --- CONCLUSION --- p.48 / APPENDIX --- p.49 / BIBLIOGRAPHY --- p.50

Tsang Tin-Tak. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 78-80). / Abstract also in Chinese. / Chapter CHAPTER ONE: --- INTRODUCTION --- p.2 / Literature Survey --- p.3 / Project overview --- p.4 / Chapter CHAPTER TWO: --- SENSOR --- p.6 / Chapter 2.1. --- Background --- p.6 / Chapter 2.1.1. --- Piezoresistive effect --- p.6 / Chapter 2.1.2. --- Wheatstone bridge --- p.7 / Chapter 2.2. --- Strain Gauge --- p.10 / Chapter 2.2.1. --- Experimental setup for strain gauge --- p.11 / Chapter 2.2.2. --- Position of the strain gauge --- p.12 / Chapter 2.2.3. --- Selection of the value for the resistor to complete the bridge --- p.13 / Chapter 2.3. --- Pressure sensor --- p.15 / Chapter 2.3.1. --- Structure of pressure sensor die --- p.15 / Chapter 2.3.2. --- Modeling of the pressure sensor die --- p.17 / Chapter 2.3.3. --- Alternative application of the pressure sensor die --- p.20 / Chapter CHAPTER THREE: --- WIRELESS TRANSMISSION --- p.24 / Chapter 3.1. --- Introduction --- p.24 / Chapter 3.2. --- Analogue Transmission --- p.25 / Chapter 3.2.1. --- Transmitter (MC2833) --- p.26 / Chapter 3.2.2. --- Receiver (MC13135) --- p.29 / Chapter 3.3. --- Digital transmission --- p.30 / Chapter 3.3.1. --- Advantage of using Digital transmission --- p.30 / Chapter 3.3.2. --- Digital Transmitter and receiver 1 (H2000 & RX2020) --- p.30 / Chapter 3.3.3. --- Digital Transmitter and receiver 2 (TX2) --- p.32 / Chapter 3.4. --- Comparison between the three sets of transmitter --- p.34 / Chapter 3.4.1. --- Analogue Vs Digital --- p.34 / Chapter 3.4.2. --- Number of components (Complexity) --- p.35 / Chapter 3.4.3. --- Excepted size --- p.35 / Chapter 3.4.4. --- Transmitting distance --- p.36 / Chapter 3.4.5. --- Power supply --- p.36 / Chapter 3.4.6. --- Conclusion --- p.36 / Chapter 3.5. --- The detail investigation of HX2000 and RX2020/RX2056 --- p.37 / Chapter 3.5.1. --- Transmitting distance --- p.37 / Chapter 3.5.2. --- Shape of the received signal --- p.37 / Chapter 3.5.3. --- Orientation of the chips --- p.39 / Chapter 3.5.4. --- Conclusion for the transmitter --- p.39 / Chapter CHAPTER FOUR: --- ENCODING AND DECODING CIRCUIT --- p.40 / Chapter 4.1. --- Introduction --- p.40 / Chapter 4.2. --- Serial binary converter (MAX 1240) --- p.40 / Chapter 4.2.1. --- Features of MAX1240 --- p.41 / Chapter 4.2.2. --- Implementation of MAX1240 --- p.43 / Chapter 4.2.3. --- Method to decode the signal generated by MAX1240 --- p.46 / Chapter 4.3. --- Voltage-to-Frequency Converter (AD654) --- p.52 / Chapter 4.3.1. --- Advantages of using AD654 as the A/D converter --- p.54 / Chapter 4.3.2. --- Disadvantages of using AD654 as the A/D converter --- p.55 / Chapter 4.3.3. --- Method to read the frequency --- p.56 / Chapter 4.4. --- Frequency counter --- p.57 / Chapter 4.4.1. --- Schmitt trigger NAND-gate --- p.58 / Chapter 4.4.2. --- Ripple counter --- p.61 / Chapter 4.4.3. --- Implementation of the counter --- p.63 / Chapter 4.5. --- Conclusion --- p.66 / Chapter CHAPTER FIVE: --- INTERGATION OF THE THREE COMPONENTS --- p.67 / Implementation of the Circuit --- p.67 / Chapter 5.2. --- The result before transmission --- p.70 / Chapter 5.2.1. --- Analysis and Discussion for the experimental result (before transmission) --- p.72 / Chapter 5.3. --- The result after transmission --- p.74 / Chapter 5.3.1. --- Analysis and Discussion for the experimental result (after transmission) --- p.76 / Chapter CHAPTER SIX: --- SUMMARY --- p.77 / BIBLIOGRAPHY --- p.78