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The Global ETD Search service is a free service for researchers
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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.
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Showing 1 to 9 of 9 (0.091 seconds)Spelling suggestions: "subject:"gyroscopic instruments"" "subject:"croscopic instruments""
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CMOS systems and circuits for sub-degree per hour MEMS gyroscopesSharma, Ajit. January 2007 (has links)
Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Farrokh Ayazi; Committee Member: Jennifer Michaels; Committee Member: Levent Degertekin; Committee Member: Paul Hasler; Committee Member: W. Marshall Leach. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Testing the HG1700 inertial measurement unit for implementation into the AIRES unmanned underwater vehicleGow, Joel A. 06 1900 (has links)
The ARIES Unmanned Underwater Vehicle (UUV) currently uses an Inertial Measurement Unit (IMU) with an inherent rotation rate error bias of 10 degrees/hour. Then need for a more accurate IMU for long term missions has led to the purchase of the Honeywell HG1700 IMU. The HG1700 is a ring laser gyroscope designed specifically as part of the navigation software in multiple U.S. missiles. The objective of this research is to perform numerous bench tests on the HG1700 to test its capabilities and to begin the process of implementing the IMU into the ARIES unmanned underwater vehicle. Specifically, the IMU is tested for correct setup configurations, angle of rotation accuracies, the rotation rate error bias, and positional accuracies. Also, guidelines for integrating the IMU with the current software in the ARIES vehicle are discussed.
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Learning approaches for the early detection of kickback in chainsawsArnold, Drew D. 27 November 2012 (has links)
Among the many safety hazards facing chainsaw operators, the phenomenon known as kickback is the most dangerous. Kickback occurs when the chain at the tip of the chainsaw is caused to stop abruptly, and transfers the energy of the cutting chain to motion of the saw. The saw will rotate backward toward the operator rapidly. The limited amount of published research on the topic of chainsaw kickback was conducted to develop standardized testing for consumer chainsaws. Modern chainsaws are equipped with safety measures such as low-kickback cutting chains and hand-guard braking mechanisms. These mechanisms have greatly improved the safety of chainsaws, but their inherent mechanical simplicity leaves room for improvement.
The current work presents the research that analyzed the possible methods for detecting kickback electronically. Phase 1 of this work utilized a set of two accelerometers and a single gyroscope to determine if it is possible to distinguish a kickback event from normal cutting operations. A method for applying weighting coefficients to the three sensor readings, then summing the three signal values was optimized to obtain the greatest margin between kickback and normal cutting. The result of this study was that kickback is most easily identified by using only a gyroscope and setting a threshold. Phase 2 focused on detecting kickback as early as possible. Three methods were attempted: Signal Differentiation, a Simplified Bag of Words method, and applying a Support Vector Machine with selective undersampling and a stack of classifier vectors. Signal differentiation, while detecting the kickback events earlier, also suffered from many false positives. The Bag of Words method was unsuccessful in creating results different than the threshold method from Phase 1. The Support Vector Machine classification was able to detect kickback an average of 19.4 ms before the simple threshold method with no occurrence of either false positives or false negatives. This method is the most reliable and provides the greatest likelihood of detecting kickback early. / Graduation Date: 2013
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Embedded system software development for a single-gimbaled control moment gyroscope and the vibration damping of a clamped-free cantilevered beam.Shi, Jian-Feng. January 2004 (has links)
Thesis (M.A. Sc.)--University of Toronto, 2004. / Adviser: Chris Damaren.
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Development of a Control Moment Gyroscope controlled, three axis satellite simulator, with active balancing for the bifocal relay mirror initiative /Kulick, Wayne J. January 2004 (has links) (PDF)
Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, Dec. 2004. / Thesis Advisor(s): Brij N. Agrawal. Includes bibliographical references (p. 103-104). Also available online.
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Testing the HG1700 inertial measurement unit for implementation into the AIRES unmanned underwater vehicle /Gow, Joel A. January 2005 (has links) (PDF)
Thesis (M.S. in Applied Science (Physical Oceanography))--Naval Postgraduate School, June 2005. / Thesis Advisor(s): Anthony J. Healey, Edward B. Thornton. Includes bibliographical references (p. 49). Also available online.
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Development of a Control Moment Gyroscope controlled, three axis satellite simulator, with active balancing for the bifocal relay mirror initiativeKulick, Wayne J. 12 1900 (has links)
Approved for public release; distribution in unlimited. / This thesis develops and implements a Control Moment Gyroscope (CMG) steering law, controller and active balancing system for a three-axis satellite simulator (TASS). The CMGs are configured in a typical pyramid configuration (the fourth CMG position being null). The development was done primarily with simulation and experiments utilizing Real Time Workshop and XPC Target of MATLAB and SIMULINK. The TASS is a double circular platform mounted on a spherical air bearing with the center of rotation (CR) about the approximate physical geometric center of the simulator. The TASS utilizes three moveable masses in the three body axes for balancing which actively eliminate any center of gravity (CG) offset and return the CG to the CR. The TASS supports an optics payload designed to acquire, track and point a received laser beam onto an off-satellite target. The target may be stationary or moving. Actively balancing the TASS reduces the torque output requirement for the CMGs while maintaining either a stabilized level platform or a particular commanded attitude. Reduction or elimination of torque output from the CMGs results in a more stabilized platform, less structural induced vibration, less jitter in payload optics and less power required in spacecraft applications. / Lieutenant Commander, United States Navy
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CMOS systems and circuits for sub-degree per hour MEMS gyroscopesSharma, Ajit 14 November 2007 (has links)
The objective of our research is to develop system architectures and CMOS circuits that interface with high-Q silicon microgyroscopes to implement navigation-grade angular rate sensors. The MEMS sensor used in this work is an in-plane bulk-micromachined mode-matched tuning fork gyroscope (M² – TFG
), fabricated on silicon-on-insulator substrate. The use of CMOS transimpedance amplifiers (TIA) as front-ends in high-Q MEMS resonant sensors is explored. A T-network TIA is proposed as the front-end for resonant capacitive detection. The T-TIA provides on-chip transimpedance gains of 25MΩ, has a measured capacitive resolution of 0.02aF /√Hz at 15kHz, a dynamic range of 104dB in a bandwidth of 10Hz and consumes 400μW of power. A second contribution is the development of an automated scheme to adaptively bias the mechanical structure, such that the sensor is operated in the mode-matched condition. Mode-matching leverages the inherently high quality factors of the microgyroscope, resulting in significant improvement in the Brownian noise floor, electronic noise, sensitivity and bias drift of the microsensor. We developed a novel architecture that utilizes the often ignored residual quadrature error in a gyroscope to achieve and maintain perfect mode-matching (i.e.0Hz split between the drive and sense mode frequencies), as well as electronically control the sensor bandwidth. A CMOS implementation is developed that allows mode-matching of the drive and sense frequencies of a gyroscope at a fraction of the time taken by current state of-the-art techniques. Further, this mode-matching technique allows for maintaining a controlled separation between the drive and sense resonant frequencies, providing a means of increasing sensor bandwidth and dynamic range. The mode-matching CMOS IC, implemented in a 0.5μm 2P3M process, and control algorithm have been interfaced with a 60μm thick M2−TFG to implement an angular rate sensor with bias drift as low as 0.1°/hr ℃ the lowest recorded to date for a silicon MEMS gyro.
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Interface circuits for readout and control of a micro-hemispherical resonating gyroscopeMayberry, Curtis Lee 12 January 2015 (has links)
Gyroscopes are inertial sensors that measure the rate or angle of rotation. One of the most promising technologies for reaching a high-performance MEMS gyroscope has been development of the micro-hemispherical shell resonator. (μHSR) This thesis presents the electronic control and read-out interface that has been developed to turn the μHSR into a fully functional micro-hemispherical resonating gyroscope (μHRG) capable of measuring the rate of rotation. First, the μHSR was characterized, which both enabled the design of the interface and led to new insights into the linearity and feed-through characteristics of the μHSR. Then a detailed analysis of the rate mode interface including calculations and simulations was performed. This interface was then implemented on custom printed circuit boards for both the analog front-end and analog back-end, along with a custom on-board vacuum chamber and chassis to house the μHSR and interface electronics. Finally the performance of the rate mode gyroscope interface was characterized, showing a linear scale factor of 8.57 mv/deg/s, an angle random walk (ARW) of 34 deg/sqrt(hr) and a bias instability of 330 deg/hr.
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