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1
Azgin, Kivanc. "High Performance Mems Gyroscopes." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608194/index.pdf.
Full textAbstract:
This thesis reports development of three different high performance, low g-sensitive micromachined gyroscopes having single, double, and quadruple masses. The single mass gyroscope (SMG) is developed for comparison of its performance with the double mass gyroscope (DMG) and quadruple mass gyroscope (QMG). DMG is a tuning fork gyroscope, diminishing the effects of unpredictable g-loadings during regular operation, while QMG is a twin tuning fork gyroscope, developed for a uniform and minimized g-sensitivity. DMG and QMG use novel ring spring connections for merging the masses in drive modes, providing uniform and anti-phase drive mode vibrations that minimize the cross-coupling and the effects of intrinsic and extrinsic accelerations on the scale factor and bias levels of the gyroscopes. The sense mode of each mass of the multi-mass gyroscopes is designed to have higher resonance frequencies than that of the drive mode for possible matching requirements, and these sense modes have dedicated frequency tuning electrodes for frequency matching or tuning. Detailed performance simulations are performed with a very sophisticated computer model using the ARCHITECT software.
These gyroscopes are fabricated using a standard SOIMUMPs process of MEMSCAP Inc., which provides capacitive gaps of 2 µm and structural layer thickness of 25 µ
m. Die sizes of the fabricated gyroscope chips are 4.1 mm x 4.1 mm for the single mass, 4.1 mm x 8.9 mm for the double mass, and 8.9 mm x 8.9 mm for the quadruple mass gyroscope. Fabricated gyroscopes are tested with dedicated differential readout electronics constructed with discrete components. Drive mode resonance frequencies of these gyroscopes are in a range of 3.4 kHz to 5.1 kHz. Depending on the drive mode mechanics, the drive mode quality (Q) factors of the fabricated gyroscopes are about 300 at atmospheric pressure and reaches to a value of 2500 at a vacuum ambient of 50 mTorr. Resolvable rates of the fabricated gyroscopes at atmospheric pressure are measured to be 0.109 deg/sec, 0.055 deg/sec, and 1.80 deg/sec for SMG, DMG, and QMG, respectively. At vacuum, the respective resolutions of these gyroscopes improve significantly, reaching to 106 deg/hr with the SMG and 780 deg/hr with the QMG, even though discrete readout electronics are used. Acceleration sensitivity measurements at atmosphere reveal that QMG has the lowest bias g-sensitivity and the scale factor g sensitivity of 1.02deg/sec/g and 1.59(mV/(deg/sec))/g, respectively. The performance levels of these multi-mass gyroscopes can be even further improved with high performance integrated capacitive readout electronics and precise sense mode phase matching.
2
Johnson, Brian. "The electronic control of gyroscopes." Thesis, University of Bath, 1985. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.767553.
Full textAbstract:
The work reported in this thesis describes the design and implementation of three electronic controllers for a miniature two axis gyroscope. In particular the design is based upon the Microflex Gyroscope, which is manufactured by British Aerospace. Two variants of the Microflex gyroscope have been considered; the combined pickoff and torquer gyroscope and the separate pickoff and torquer gyroscope. These two gyroscopes are mechanically identical but feature different pickoff and torquer arrangements. The thesis traces the history of the gyroscope from its origins to the development of small two axis rate sensors. It includes a detailed description of the Microflex gyroscope and develops mathematical models to describe its behaviour. The electronic controllers are used to sense the angular displacement of the gyroscope, condition these signals then apply them as feedback to the gyroscope to null the displacement. The control is applied in the form of a type II servo system, hence the output from the system is a measure of the angular rate which is applied to the gyroscope. The design of an analogue controller is developed for the combined pickoff and torquer gyroscope. The restrictions of the design of the controller due to this transducer configuration are identified. To overcome these restrictions and to increase the design options an analogue controller for the separate pickoff and torquer gyroscope was developed and implemented. This work lead into the design and implementation of a digital controller. The advantages of this design over a traditional analogue system are discussed. Both modelled and practical results for all three systems are presented in the thesis. These show that design objectives can be achieved using simple design rules which have been developed as the designs progressed.
3
Zarinetchi, Farhad. "Studies in optical resonator gyroscopes." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/13227.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1992.Includes bibliographical references (leaves 193-194).
by Farhad Zarinetchi.
Ph.D.
4
Shao, Peng. "Microscale hemispherical shell resonating gyroscopes." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54266.
Full textAbstract:
MEMS gyroscopes are electromechanical devices that measure rate or angle of rotation. They are one of the fastest growing segments of the microsensor market. Advances in microfabrication technologies have enabled the implementation of chip scale monolithic gyroscopes (MEMS gyroscopes) with very small form factor that are lightweight and consume little power. Over the past decade, significant amount of research have been directed towards the development of high performance and very small size MEMS gyroscopes for applications in consumer electronics such as smart phones. In this dissertation, high aspect-ratio hemispherical shell structure with continuously curved surface is utilized as the high Q resonator. Being an axial symmetric structure, the 3D hemispherical shell is able to achieve low frequency (3 ~ 5 kHz) within 2 mm X 2mm die area. Detailed analysis on energy dissipation also shows its potential to achieve ultra-high quality factor with the selection of high Q material and proper design of support structure. This dissertation presents, for the first time, the analysis, design, fabrication and characterization of a micro-hemispherical resonating gyroscope (μHRG) that has the potential to be used as a whole angle micro-gyroscope. A three-dimensional high aspect-ratio poly- and single crystalline silicon (3D HARPSS) process is developed to fabricate free-standing, stem-supported hemispherical shell with self-aligned deep electrodes for driving, sensing and quadrature control of the gyroscope. This monolithic process consists of seven lithography steps and combines 3D micro-structure with curved surfaces with the HARPSS process to create capacitive electrodes with arbitrary gaps around the micro-hemispherical shell resonator (μHSR). Polysilicon is utilized as the structural material due to its isotropic mechanical properties and the potential of achieving high quality factor. The fabrication is demonstrated successfully by prototypes of polysilicon μHRG with diameter of 1.2 mm and thickness of 700 nm. Frequency response and gyro operation are electronically measured using the integrated electrodes. Quality factor of 8,500 is measured with frequency mismatch of 105 Hz. Electronic mode matching and alignment are successfully performed by applying tuning voltages and quadrature nulling voltages. An open loop rate sensitivity scale factor of 4.42 mV/°/s was measured. Design and process optimization of the support structure improved the quality factor to 40,000. Further improvement of quality factor will enable the demonstration of high performance RIG using polysilicon μHRG.
5
Gow, Joel A. "Testing the HG1700 inertial measurement unit for implementation into the AIRES unmanned underwater vehicle." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Jun%5FGow.pdf.
Full textAbstract:
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.
6
Rabeendran, Nishanthan. "A Study of Ring Laser Gyroscopes." Thesis, University of Canterbury. Physics and Astronomy, 2008. http://hdl.handle.net/10092/1989.
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This thesis presents a study of a 1.6 metre square, helium-neon based ring laser gyroscope (denoted PR-1). This device is mounted on one of the internal walls of a high rise building. After optimisation a cavity Q of 2.9x10¹¹ and a sensitivity to rotation of approximately 10⁻³ of the background Earth bias was obtained. A detailed investigation of the single mode operating regime and multi-mode thresholds was undertaken and could be well accounted for with a simple model of the gain curves. A key feature of the operation of PR-1 is persistent longitudinal mode hopping. It is shown that by running the laser at selective high powers, one obtains CW mode locked operation thereby negating the influence of mode hopping and allowing for long time data acquisition. PR-1 was used to demonstrate oscillation of the Rutherford building on its second fundamental mode during an earthquake. In a separate investigation, a range of supermirrors were studied to determine the optimum configuration in a 4 by 4 metre ring laser. The set with the highest finesse prevailed despite the comparatively low light levels on the photo detectors. The geometric stability of the lasers was not found to be a significant factor.
7
Sharma, Mrigank. "Design and modeling of advanced gyroscopes." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/1889.
Full textAbstract:
This thesis reports on a design and modeling of a micro-machined gyroscope.
The proposed sensor is a dual mass type, electro-statically driven to primary mode oscillation and senses, capacitively, the output signal. Full decoupling between drive and sense modes minimizes the mechanical crosstalk and based on this a novel gyroscope is designed and modeled which has separate
sensing and driving masses. The dual mass gyroscope is designed such that driving and sensing resonant frequency is 23101 Hz with 0% mismatch (in simulation)with quality factor of 31.6227 and bandwidth of 730.51Hz.
The gyroscope when actuated in simulation with 25V ac and 10V dc showed sensing capacitance variation of 126aF for 1 rad/s with base capacitance of 244.16fF. To the design of the gyroscope a new semi automatic tool was formulated for the noise analysis and noise based optimization of the resonant
MEMS structures. Design of a sensitive gyroscope needs to take into account
the noise shaping induced by damping phenomena at micro scale and
is critical for optimization. The analysis was further extended to the design
of the gyroscope and estimation shows that there is a trade of between the
S/N ratio and the sensitivity and the design could be made much better
in-terms of S/N by tuning its resonant frequency to 10⁶Hz.
8
Sung, Wang-Kyung. "High-frequency tri-axial resonant gyroscopes." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52936.
Full textAbstract:
This dissertation reports on the design and implementation of a high-frequency, tri-axial capacitive resonant gyroscopes integrated on a single chip. The components that construct tri-axial rotation sensing consist of a yaw, a pitch and a roll device. The yaw-rate gyroscope has a wide bandwidth and a large full-scale range, and operates at a mode-matched condition with DC polarization voltage of 10V without frequency tuning requirement. The large bandwidth of 3kHz and expected full-scale range over 30,000˚/sec make the device exhibit fast rate response for rapid motion sensing application. For the pitch-and-roll rate sensing, an in-plane drive-mode and two orthogonal out-of-plane sense-modes are employed. The rotation-rate sensing from lateral axes is performed by mode-matching the in-plane drive-mode with out-of-plane sense-modes to detect Coriolis-force induced deflection of the resonant mass. To compensate process variations and thickness deviations in the employed silicon-on-insulator (SOI) substrates, large electrostatic frequency tunings of both the drive and sense modes are realized. A revised high aspect ratio combined polysilicon and silicon (HARPSS) process is developed to resolve the Coriolis response that exists toward out-of-plane direction while drive-mode exists on in-plane, and tune individual frequencies with minimal interference to unintended modes. To conclude and overcome the performance limitation, design optimization of high-frequency tri-axial gyroscopes is suggested. Q-factor enhancement through reduction of thermoelastic damping (TED) and optimizations of physical dimensions are suggested for the yaw disk gyroscope. For the pitch-and-roll gyroscope, scaling property of physical dimension and its subsequent performance enhancement are analyzed.
9
Patil, Nishad. "Design And Analysis Of MEMS Angular Rate Sensors." Thesis, Indian Institute of Science, 2006. http://hdl.handle.net/2005/291.
Full textAbstract:
Design and analysis of polysilicon and single crystal silicon gyroscopes have been carried out. Variations in suspension design have been explored. Designs that utilize in-plane and out-of-plane sensing are studied.
Damping plays an important role in determining the sense response. Reduction in damping directly affects sensor performance. The various damping mechanisms that are prevalent in gyroscopes are studied.
Perforations on the proof mass are observed to significantly reduce the damping in the device when operated in air. The effects of perforation geometry and density have been analyzed. The analysis results show that there is a two orders of magnitude reduction in damping of thick gyroscope structures with optimized perforation design.
Equivalent circuit lumped parameter models have been developed to analyze gyroscope performance. The simulation results of these models have been compared with results obtained from SABER, a MEMS specific system level design tool from Coventor-ware. The lumped parameter models are observed to produce faster simulation results with an accuracy comparable to that of Coventorware
Three gyroscopes specific to the PolyMUMPS fabrication process have been designed and their performance analyzed. Two of the designs sense motion out-of-plane and the other senses motion in-plane. Results of the simulation show that for a given damping, the gyro design with in-plane modes gives a resolution of 4◦/s. The out-of-plane gyroscopes have two variations in suspension. The hammock suspension resolves a rate of 25◦/s in a 200 Hz bandwidth while the design with folded beam suspension resolves a rate of 2◦/s in a 12 Hz bandwidth. A single crystal silicon in-plane gyroscope has been designed with vertical electrodes to sense Coriolis motion. This design gives an order of magnitude higher
capacitance change for a given rotation in comparison to conventional comb-finger design.
The effects of process induced residual stress on the characteristic frequencies of the polysilicon gyroscopes are also studied. The in-plane gyroscope is found to be robust to stress variations. Analysis results indicate that the tuning fork gyroscope with the hammock suspension is the most susceptible to compressive residual stress, with a significant drop in sensitivity at high stress values.
10
Steward, Victoria. "Modeling of a folded spring supporting MEMS gyroscope." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-1007103-133256/.
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11
Bel, Olivier. "Gyromètre à quartz 2-D micro-usine." Besançon, 2001. http://www.theses.fr/2001BESA2010.
Full textAbstract:
Indispensables pour la navigation inertielle, les gyroscopes et les gyromètres font l'objet de nombreuses recherches, particulièrement dans le domaine microtechnique. Le travail de recherche proposé par SFIM industries (puis SAGEM à partir de 1999) consistait à démontrer le principe d'une mesure sur deux axes de la vitesse angulaire, principe dont le brevet est détenu par SFIM. Le principe d'usinabilité du quartz par attaque chimique de dispositifs de ce type ayant été démontré dans un avant-projet, il restait à valider le principe de fonctionnement par la réalisation du capteur et de l'électronique permettant de mesurer la vitesse angulaire. . .
12
Johari, Houri. "Micromachined capacitive silicon bulk acoustic wave gyroscopes." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/31656.
Full textAbstract:
Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Dr. Farrokh Ayazi; Committee Co-Chair: Dr. F. Levant Degertekin; Committee Member: Dr. Paul Kohl; Committee Member: Dr. Peter Hesketh; Committee Member: Dr. Suresh K. Sitaraman. Part of the SMARTech Electronic Thesis and Dissertation Collection.
13
Graham, Richard Douglas. "New Concepts for Operating Ring Laser Gyroscopes." Thesis, University of Canterbury. Physics and Astronomy, 2010. http://hdl.handle.net/10092/5058.
Full textAbstract:
A ring laser gyroscope (gyro) is an active laser interferometer designed to sense rotation through the Sagnac frequency shift encountered by two beams travelling in opposite directions around a closed path. The classes of devices considered in this thesis are the large and ultra-large ring laser gyros. These instruments are designed
for direct measurement of earth rotation rate and find applications in geodesy, geophysics, and tests of physical theories.
The research presented in this thesis focuses on the demonstration of new techniques for operating ring laser gyros. The main goal of these techniques has been the
correction for variations in the geometry of an ultra-large ring laser gyro, UG-3. This instrument is a 77 m perimeter ultra-large ring laser gyro of heterolithic construction
and is the primary instrument used in the experiments presented here.
UG-3 has been used to demonstrate measurement of earth strains which have been used to correct for changes in the geometry of the instrument. It has also been used to demonstrate a control technique where the co-rotating beams were alternately offset allowing the number of wavelengths around the perimeter to be counted and a Sagnac rotation signal to be obtained.
Among the most important outcomes of this research of interest to the large ring laser gyro community is that we now understand most of the problems that would affect a next generation ring laser gyro. This understanding allows us to choose an operational technique best suited to the measurements being made and thus maximise
the scientific potential of the instrument. Additionally, the development of a new standard for data storage and an associated suite of software to acquire, query and
analyse ring laser data is expected to improve collaboration with the wider research community.
Other research outcomes of more general interest include the analysis of how oscillation of a single mode is established in a high finesse laser cavity. We demonstrate that the ultimate mode of operation can be selected with a ‘seed’ beam of exceptionally low intensity. An interesting related outcome is the demonstration of Sagnac beat
frequency measurement during the ring down of a ring cavity, a type of measurement immune to dispersive and flow related frequency shifts.
14
Poreddy, Surender Reddy. "Design and dynamic analysis of MEMS gyroscopes /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1422956.
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15
Erismis, Mehmet Akif. "Mems Accelerometers And Gyroscopes For Inertial Measurement Units." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605331/index.pdf.
Full textAbstract:
This thesis reports the development of micromachined accelerometers and gyroscopes that can be used for micromachined inertial measurement units (IMUs). Micromachined IMUs started to appear in the market in the past decade as low cost, moderate performance alternative in many inertial applications including military, industrial, medical, and consumer applications. In the framework of this thesis, a number of accelerometers and gyroscopes have been developed in three different fabrication processes, and the operation of these fabricated devices is verified with extensive tests. In addition, the fabricated accelerometers were combined with external readout electronics to obtain hybrid accelerometer systems, which were tested in industrial test facilities.
The accelerometers and gyroscopes are designed and optimized using the MATLAB analytical simulator and COVENTORWARE finite element simulation tool. First set of devices is fabricated using a commercial foundry process called SOIMUMPs, while the second set of devices is fabricated using the electroplating processes developed at METU-MET facilities. The third set of devices is designed for a new advanced process based on DRIE, which is under development.
Mechanical and electrical test results of the fabricated accelerometers and gyroscopes are in close agreement with the designed values. The testing of the SOI and nickel accelerometers is also performed in industrial test environments. In order to perform these tests, accelerometers are hybrid connected to commercially available capacitive readout circuits. These accelerometer systems require only two DC supply voltages for operation and provide an analog output voltage related to the input acceleration. The industrial tests show that the SOI accelerometer system yields a 799 µg/&
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Hz average noise floor, a 1.8 mg/&
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Hz peak noise floor, a 22.2 mV/g sensitivity, and a 0.1 % nonlinearity, while the nickel accelerometer system yields a 228 µ
g/&
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Hz average noise floor, a 375 µ
g/&
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Hz peak noise floor, a 1.02 V/g sensitivity, and a 0.23 % nonlinearity. Long-term drift components of the accelerometers are determined to be smaller than 20 mg. These systems are the highest performance micromachined accelerometer systems developed in Turkey, and they can be used in implementation of a national inertial measurement unit.
16
Alper, Said Emre. "Mems Gyroscopes For Tactical-grade Inertial Measurement Applications." Phd thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606483/index.pdf.
Full textAbstract:
This thesis reports the development of high-performance symmetric and decoupled micromachined gyroscopes for tactical-grade inertial measurement applications. The symmetric structure allows easy matching of the resonance frequencies of the drive and sense modes of the gyroscopes for achieving high angular rate sensitivitywhile the decoupled drive and sense modes minimizes mechanical cross-coupling for low-noise and stable operation. Three different and new symmetric and decoupled gyroscope structures with unique features are presented. These structures are fabricated in four different micromachining processes: nickel electroforming (NE), dissolved-wafer silicon micromachining (DWSM), silicon-on-insulator (SOI) micromachining, and silicon-on-glass (SOG) micromachining. The fabricated gyroscopes have capacitive gaps from 1.5µ
m to 5.5µ
m and structural layer thicknesses from 12µ
m to 100µ
m, yielding aspect ratios up to 20 depending on the fabrication process. The size of fabricated gyroscope chips varies from 1x1mm2 up to 4.2x4.6mm2. Fabricated gyroscopes are hybrid-connected to a designed capacitive interface circuit, fabricated in a standard 0.6µ
m CMOS process. They have resonance frequencies as small as 2kHz and as large as 40kHz
sense-mode resonance frequencies can be electrostatically tuned to the drive-mode frequency by DC voltages less than 16V. The quality factors reach to 500 at atmospheric pressure and exceed 10,000 for the silicon gyroscopes at vacuum. The parasitic capacitance of the gyroscopes on glass substrates is measured to be as small as 120fF. The gyroscope and interface assemblies are then combined with electronic control and feedback circuits constructed with off-the-shelf IC components to perform angular rate measurements. Measured angular rate sensitivities are in the range from 12µ
V/(deg/sec) to 180µ
V/(deg/sec), at atmospheric pressure. The SOI gyroscope demonstrates the best performance at atmospheric pressure, with noise equivalent rate (NER) of 0.025(deg/sec)/Hz1/2, whereas the remaining gyroscopes has an NER better than 0.1(deg/sec)/Hz1/2, limited by either the small sensor size or by small quality factors. Gyroscopes have scale-factor nonlinearities better than 1.1% with the best value of 0.06%, and their bias drifts are dominated by the phase errors in the demodulation electronics and are over 1deg/sec. The characterization of the SOI and SOG gyroscopes at below 50mTorr vacuum ambient yield angular rate sensitivities as high as 1.6mV/(deg/sec) and 0.9mV/(deg/sec), respectively. The NER values of these gyroscopes at vacuum are smaller than 50(deg/hr)/Hz1/2 and 36(deg/hr)/Hz1/2, respectively, being close to the tactical-grade application limits. Gyroscope structures are expected to provide a performance better than 10 deg/hr in a practical measurement bandwidth such as 50Hz, provided that capacitive gaps are minimized while preserving the aspect ratio, and the demodulation electronics are improved.
17
Temiz, Yuksel. "Advanced Readout And Control Electronics For Mems Gyroscopes." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12608664/index.pdf.
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This thesis reports the development of advanced readout and control electronics for MEMS gyroscopes developed at METU. These gyroscope electronics are separated into three main groups: high sensitive interface circuits, drive mode amplitude controlled self oscillation loops, and sense mode phase sensitive amplitude demodulators. The proposed circuits are first implemented with discrete components, and then integrated on CMOS chips. A self oscillation loop enabling constant amplitude drive mode vibrations independent of sensor parameters and ambient conditions is developed. A fully functional angular rate system, which is constructed by employing this advanced control electronics together with the transresistance amplifier type interfaces and sense mode electronics, is implemented on a dedicated PCB having 5.4x2.4 cm2 area. This system demonstrates an impressive performance far better than the best performance achieved by any angular rate system developed at METU. Bias instability and angle random walk values are measured as 14.3 º/hr and 0.126 º
/&
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hr, respectively. The scale factor of the system is found as 22.2 mV/(º
/sec) with a nonlinearity of 0.01%, and a zero rate output of 0.1 º
/sec, in ±
50 º
/sec measurement range. CMOS unity gain buffer (UGB) and transimpedance amplifier (TIA) type resistive and capacitive interfaces are characterized through AC, transient, and noise tests. It is observed that on chip biasing mechanisms properly DC-bias the high impedance nodes to 0 V potential. UGB type capacitive interfaces demonstrate superior performance than TIA counterparts due to stability problems associated with TIA interfaces. CMOS differential drive mode control and sense mode demodulation electronics give promising results for the future performance tests.
18
Dreyer, Antonie Christoffel. "Modelling of MEMS vibratory gyroscopes utilizing phase detection." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/823.
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Miao, Binglin. "Design, fabrication, and characterization of microring resonators used in micro gyroscopes." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 5.09 Mb., 85 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1432292.
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20
Moussa, Hassan. "Gyrometres vibrants à sortie fréquentielle." Besançon, 2005. http://www.theses.fr/2005BESA2038.
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21
Constancis, Pierre. "Modélisation et commande des gyroscopes secs accordés d'une centrale inertielle à composants liés." Paris 9, 1990. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=1990PA090005.
Full textAbstract:
Cette étude présente la modélisation mécanique d'un gyroscope sec accordé balourde et son application à la conception d'un système inertiel à composants liés de grand bande passante. Les performances mesurées sont aussi données. On présente d'abord un modèle non stationnaire du gyroscope à deux degrés de liberté qui prend en compte couplages d'axes, défauts d'accord, balourd et rectification cinématique. Puis on présente la conception d'un estimateur et d'un asservissement numérique, pour estimer la vitesse angulaire et l'accélération (plus précisément accélération moins la gravité) d'un système inertiel compose de trois gyroscopes balourdes
22
Patil, Nishad. "Design And Analysis Of MEMS Angular Rate Sensors." Thesis, Indian Institute of Science, 2006. http://etd.iisc.ac.in/handle/2005/439.
Full textAbstract:
Design and analysis of polysilicon and single crystal silicon gyroscopes have been carried out. Variations in suspension design have been explored. Designs that utilize in-plane and out-of-plane sensing are studied.
Damping plays an important role in determining the sense response. Reduction in damping directly affects sensor performance. The various damping mechanisms that are prevalent in gyroscopes are studied. Perforations on the proof mass are observed to significantly reduce the damping in the device when operated in air. The effects of perforation geometry and density have been analyzed. The analysis results show that there is a two orders of magnitude reduction in damping of thick gyroscope structures with optimized perforation design.
Equivalent circuit lumped parameter models have been developed to analyze gyroscope performance. The simulation results of these models have been compared with results obtained from SABER, a MEMS specific system level design tool from Coventorware. The lumped parameter models are observed to produce faster simulation results with an accuracy comparable to that of Coventorware
Three gyroscopes specific to the PolyMUMPS fabrication process have been designed and their performance analyzed. Two of the designs sense motion out-of-plane and the other senses motion in-plane. Results of the simulation show that for a given damping, the gyro design with in-plane modes gives a resolution of 4º/s. The out-of-plane gyroscopes have two variations in suspension. The hammock suspension resolves a rate of 25º/s in a 200 Hz bandwidth while the design with folded beam suspension resolves a rate of 2º/s in a 12 Hz bandwidth. A single crystal silicon in-plane gyroscope has been designed with vertical electrodes to sense Coriolis motion. This design gives an order of magnitude higher
Capacitance change for a given rotation in comparison to conventional comb-finger design.
The effects of process induced residual stress on the characteristic frequencies of the polysilicon gyroscopes are also studied. The in-plane gyroscope is found to be robust to stress variations. Analysis results indicate that the tuning fork gyroscope with the hammock suspension is the most susceptible to compressive residual stress, with a significant drop in sensitivity at high stress values.
23
Silay, Kanber Mithat. "High Performance Cmos Capacitive Interface Circuits For Mems Gyroscopes." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607518/index.pdf.
Full textAbstract:
This thesis reports the development and analysis of high performance CMOS readout electronics for increasing the performance of MEMS gyroscopes developed at Middle East Technical University (METU). These readout electronics are based on unity gain buffers implemented with source followers. High impedance node biasing problem present in capacitive interfaces is solved with the implementation of a transistor operating in the subthreshold region.
A generalized fully differential gyroscope model with force feedback electrodes has been developed in order to simulate the capacitive interfaces with the model of the gyroscope. This model is simplified for the single ended gyroscopes fabricated at METU, and simulations of resonance characteristics are done.
Three gyroscope interfaces are designed by considering the problems faced in previous interface architectures. The first design is implemented using a single ended source follower biased with a subthreshold transistor. From the simulations, it is observed that biasing impedances up to several gigaohms can be achieved. The second design is the fully differential version of the first design with the addition of a self biasing scheme. In another interface, the second design is modified with an instrumentation amplifier which is used for fully differential to single ended conversion. All of these interfaces are fabricated in a standard 0.6 µm CMOS process. Fabricated interfaces are characterized by measuring their ac responses, noise response and transient characteristics for a sinusoidal input. It is observed that, biasing impedances up to 60 gigaohms can be obtained with subthreshold transistors. Self biasing architecture eliminates the need for biasing the source of the subthreshold transistor to set the output dc point to 0 V. Single ended SOG gyroscopes are characterized with the single ended capacitive interfaces, and a 45 dB gain improvement is observed with the addition of capacitive interface to the drive mode. Minimum resolvable capacitance change and displacement that can be measured are found to be 58.31 zF and 38.87 Fermi, respectively. The scale factor of the gyroscope is found to be 1.97 mV/(°
/sec) with a nonlinearity of only 0.001% in ±
100 °
/sec measurement range. The bias instability and angle random walk of the gyroscope are determined using Allan variance method as 2.158 °
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hr and 124.7 °
/hr, respectively.
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Sahin, Emre. "High Performance Readout And Control Electronics For Mems Gyroscopes." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610386/index.pdf.
Full textAbstract:
This thesis reports the development of various high performance readout and control electronics for implementing angular rate sensing systems using MEMS gyroscopes developed at METU. First, three systems with open loop sensing mechanisms are implemented, where each system has a different drive-mode automatic gain controlled (AGC) self-oscillation loop approach, including (i) square wave driving signal with DC off-set named as OLS_SquD, (ii) sinusoidal driving signal with DC off-set named as OLS_SineD, and iii) off-resonance driving signal named as OLS_OffD. A forth system is also constructed with a closed loop sensing mechanism where the drive mode automatic gain controlled (AGC) self-oscillation loop approach with square wave driving signal with DC off-set named as CLS_SquD. Sense and drive mode electronics employ transimpedance and transresistance amplifiers as readout electronics, respectively. Each of the systems is implemented with commercial discrete components on a dedicated PCB. Then, the angular rate sensing systems are tested with SOG (Silicon-on-Glass) gyroscopes that are adjusted to have two different mechanical bandwidths, more specially 100 Hz and 30 Hz. Test results of all of these cases verify the high performance of the systems.
For the 100 Hz bandwidth, the OLS_SquD system shows a bias instability of 4.67 ˚
/hr, an angle random walk (ARW) 0.080 &
#730
/&
#8730
hr, and a scale factor of 22.6 mV/(&
#730
/sec). For the 30 Hz bandwidth, the OLS_SquD system shows a bias instability of 5.12 &
#730
/hr, an ARW better than 0.017 &
#730
/&
#8730
hr, and a scale factor of 49.8 mV/(&
#730
/sec). For the 100 Hz bandwidth, the OLS_SineD system shows a bias instability of 6.92 &
#730
/hr, an ARW of 0.049 &
#730
/&
#8730
hr, and a scale factor of 17.97 mV/(&
#730
/sec). For the 30 Hz bandwidth, the OLS_SineD system shows a bias instability of 4.51 &
#730
/hr, an ARW of 0.030 &
#730
/&
#8730
hr, and a scale factor of 43.24 mV/(&
#730
/sec). For the 100 Hz bandwidth, the OLS_OffD system shows a bias instability of 8.43 &
#730
/hr, an ARW of 0.086 &
#730
/&
#8730
hr, and a scale factor of 20.97 mV/(&
#730
/sec). For the 30 Hz bandwidth, the OLS_OffD system shows a bias instability of 5.72 &
#730
/hr, an ARW of 0.046 &
#730
/&
#8730
hr, and a scale factor of 47.26 mV/(&
#730
/sec). For the 100 Hz bandwidth, the CLS_SquD system shows a bias instability of 6.32 &
#730
/hr, an ARW of 0.055 &
#730
/&
#8730
hr, and a scale factor of 1.79 mV/(&
#730
/sec). For the 30 Hz bandwidth, the CLS_SquD system shows a bias instability of 5.42 &
#730
/hr, an ARW of 0.057 &
#730
/&
#8730
hr, and a scale factor of 1.98 mV/(&
#730
/sec). For the 100 Hz bandwidth, the R2 nonlinearities of the measured scale factors of all systems are between 0.0001% and 0.0003% in the ±
100 &
#730
/sec measurement range, while for the 30 Hz bandwidth the R2 nonlinearities are between 0.0002% and 0.0062% in the ±
80&
#730
/sec measurement range. These performance results are the best results obtained at METU, satisfying the tactical-grade performances, and the measured bias instabilities and ARWs are comparable to the best results in the literature for a silicon micromachined vibratory gyroscope.
25
Cooper, George. "The design, simulation and fabrication of microengineered silicon gyroscopes." Thesis, Durham University, 1996. http://etheses.dur.ac.uk/5297/.
Full textAbstract:
This thesis is concerned with the development of a low cost resonant gyroscope, or rate of turn sensor, which is capable of being mass produced. The history and theory of the resonant gyroscope is reviewed, and then a survey of resonant gyroscope technology is presented. Two novel designs of resonant gyroscopes are described. These designs are developed using the finite element analysis method. The fabrication procedure required to manufacture these devices is also developed and presented. The fabrication procedures are based upon silicon micromachining technology developed from the semiconductor industry. Prototype structures are fabricated. The first of these devices has been demonstrated to operate successfully as a gyroscopic rate of turn sensor. A third design is also presented and developed using finite element analysis. This design demonstrates for the first time that it is possible to sense rates of turn about all three orthogonal axes independently, using just a single structure. A successful implementation of a structure of this type would eliminate the traditional requirement of one gyroscope per axis of rotation. The finite element simulations of the structure indicate that the design is suitable for mass production using silicon micromachining techniques.
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Tian, Wei. "Modeling and Data Analysis of Large Ring Laser Gyroscopes." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-130967.
Full textAbstract:
Ringlaser dienen dazu, durch genaue inertiale Messungen Rotationen ohne Bezug auf ein externes Referenzsystem lokal und praktisch in Echtzeit zu bestimmen. Sie wurden in den 1970er Jahren insbesondere für die Navigation von Flugzeugen entwickelt. In den letzten Jahrzehnten wurden Ringlaser dann so weit verbessert, dass sie nun auch als eigenständige Messinstrumente in der Geodäsie Verwendung finden. Aufgrund der erreichbaren Genauigkeit ist es inzwischen möglich, Variationen in der Erdrotation mit der dafür erforderlichen Präzision zu detektieren. Der stabilste unter den Ringlasern, der so genannte Ringlaser "G" der geodätischen Fundamentalstation Wettzell, erreicht eine Sensitivität von 1.2 x 10 -11 nrad. Damit ist dieses Instrument in der Lage, Neigungen von bis zu 1 nrad (dies entspricht einem Signal von 0.2 mas in der Polbewegung, in Änderung der Rotationsgeschwindigkeit der Erde) im täglichen und halb-täglichen Frequenzband zu messen. Motivation dieser Arbeit ist es, der in den letzten Jahren erreichten Verbesserung des Auflösungsvermögens und der Sensorstabilität Rechnung zu tragen und die für die Auswertung von Ringlaserdaten benutzten geophysikalischen Modelle weiter zu verbessern, um dadurch die variable Rotation der Erde noch präziser vermessen zu können. Die dafür relevanten Effekte werden in den einzelnen Kapiteln dieser Arbeit separat behandelt. Nach einer Einführung werden in Kapitel 2 dieser Arbeit drei lokale, topozentrische Koordinatensysteme konstruiert, mit welchen sich das zu beobachtende Sagnac-Signal eines Ringlasers in der ersten post-Newtonischen Näherung der Allgemeinen Relativitätstheorie adäquat beschrieben lässt. In Kapitel 3 wird ein verbessertes Modell für die Orientierung des Ringlasers, basierend auf Ergebnissen von Dehant et al. (1999), entwickelt. Ein in den bislang benutzten Modellen vernachlässigter Neigungsterm konnte dabei identifiziert werden. Ein Modell für die retrograde tägliche Polbewegung der Erde wird in Kapitel 4 entwickelt. Ausgehend von den dynamischen Gleichungen für eine starre Erde werden diese um elastische Effekte und Einflüsse der Mehrschichtigkeit der Erde ergänzt und die entsprechenden Euler-Liouvilleschen Gleichungen und Transfer-Funktionen abgeleitet. Gezeiteneinflüsse des Ozeans, speziell die dadurch hervorgerufene sub-tägliche Variation der Erdrotation und ozeanische Auflasteffekte, werden in Kapitel 5 behandelt. Es wird gezeigt, dass die ozeanischen Signale größer als 10 -9 Δf0 (Δf0 348 Hz für den Ringlaser "G") sind und damit in den Messdaten des Ringlasers "G" nachweisbar sein sollten. Auf Grundlage der in dieser Arbeit entwickelten Modelle wurde eine 168 Tage (30. April 17. Oktober 2010) umfassenden Datenreihe des Ringlasers "G" in Kapitel 6 ausgewertet. Für die Auswertung wurde die Software ETERNA 3.40 genutzt und entsprechend angepasst. Die tägliche retrograde Polbewegung konnte dabei mit einer Genauigkeit von 0.15 mas bestimmt werden. Diese Auswertung beweist ein weiteres Mal die Existenz eines flüssigen Erdkerns. Des weiteren konnte gezeigt werden, dass bestimmte Gezeitenparameter des halb-täglichen Frequenzbandes durch lokale Effekte beeinflusst werden. Lokal gemessene Luftdruckdaten wurden benutzt, um den Einfluss atmosphärischer Auflasteffekte auf den Ringlaser "G" zu untersuchen. Die Ergebnisse dieser Arbeit zeigen, dass sich für diese Effekte kein signifikanter Einfluss nachweisen lässt. Die Arbeit schließt mit einer Zusammenfassung der Resultate, einer Beschreibung der sich ergebenden Schlussfolgerungen und einem Ausblick auf zukünftige Arbeiten auf dem Gebiet der RinglaseranalyseRing laser gyroscopes measure inertial rotations locally and in real-time without the need for an external reference system. Initially, they were developed for aircraft navigation applications in the 1970s. With the improvement of ring laser technology during the last decades large ring laser gyroscopes (RLGs) are nowadays used as independent geodetic instruments. Due to the achievable accuracy more and more geophysical signals become observable in the data. The G-ring located at the Geodetic Observatory Wettzell is reckoned as the most stable one amongst the running large RLGs and reaches a sensitivity of 1.2 x 10 -11 nrad. Therefore, the instrument is able to detect a tilt signal of 1 nrad (equivalent to a signal of 0.2 mas in polar motion or 10 -9 Ω0 in variation of Earth rotation rate) in the diurnal and semi-diurnal band. This motivates us to improve previous geophysical models and estimate associated tilt and Earth rotation signals, which are the focuses of this Thesis. Firstly, we construct three local proper topocentric reference frames and interpret the Sagnac effect observed by large RLGs in the first post-Newtonian (PN) approximation of Einstein's theory of gravity. Secondly, in Chapter 3 we develop an improved orientation model for the Sagnac platform, based on the numerical results of Dehant et al. (1999). A missing tilt term in previous RLG tilt models is found. In Chapter 4, based on the Euler-Liouville equations or nutation transfer functions for a rigid Earth, a purely elastic Earth, a two-layered Earth and a three-layered Earth, five retrograde diurnal polar motion models are computed with the HW95 tidal potential catalogue. Thirdly, ocean tide effects (two aspects: effects on sub-daily variations of Earth rotation and loading effect on tilt) are considered in Chapter 5. We show that the Sagnac signals induced by ocean tides are larger than 10 -9 Δf0 (Δf0 348 Hz for the G-ring) and their influences are visible in the G-ring. Fourthly, based on the above-mentioned improved models and 168 days (from Apr.30 to Oct.17 in 2010) of G-ring data, in the diurnal band, we estimate the retrograde diurnal polar motion signal with an accuracy of 0.15 mas. The Earth tide software ETERNA 3.40 was adopted and modified to analyse this data. Our estimation provides one more evidence for the existence of the Earth's fluid outer core. Furthermore, we found that the tidal parameters for the G-ring are affected by the cavity and topographic effects in the semi-diurnal band. The local air pressure record is used in order to investigate the atmospheric loading effect on the G-ring by a simple regression model. Nevertheless, the preliminary result shows that no significant influence from atmospheric loading on our estimation is found. This Thesis closes with a summary of the obtained results, conclusions and suggestions how the analysis of ring laser data could be improved in future work
27
Zaman, Mohammad Faisal. "Degree-per-hour mode-matched micromachined silicon vibratory gyroscopes." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28168.
Full textAbstract:
Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.Committee Chair: Dr. Farrokh Ayazi; Committee Member: Dr. Mark G. Allen; Committee Member: Dr. Oliver Brand; Committee Member: Dr. Paul A. Kohl; Committee Member: Dr. Thomas E. Michaels.
28
Rahbarnia, Shohreh. "Synthesis and properties of helical oligothiophenes and molecular gyroscopes." Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3359908.
Full textAbstract:
Thesis (Ph. D.)--University of California, Riverside, 2009.Includes abstract. Title from first page of PDF file (viewed Jan. 29, 2009). Includes bibliographical references. Issued in print and online. Available via ProQuest Digital Dissertations.
29
Sharma, Ajit. "CMOS systems and circuits for sub-degree per hour MEMS gyroscopes." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/26636.
Full textAbstract:
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.
30
Weisman, Ryan M. "Robust longitudinal rate gyro bias estimation for reliable pitch attitude observation through utilization of a displaced accelerometer array /." Online version of thesis, 2008. http://hdl.handle.net/1850/7920.
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31
Rabeendran, Nishanthan. "New Approaches to Gyroscopic Lasers." Thesis, University of Canterbury. Physics and Astronomy, 2013. http://hdl.handle.net/10092/8609.
Full textAbstract:
This thesis presents a study of two aspects of ring laser gyroscopes: Correction of systematic errors due to optical backscatter, and development of solid-state ring laser gyroscopes.
Backscatter at the optical surfaces of ring laser gyroscopes causes systematic measurement errors. These errors were modelled and corrected for in large ring lasers. The model included backscattering, hole burning and dispersion in the gain medium. The model predictions were used in conjunction with measurements of
the intensity modulation of each beam and the phase difference between these modulation to correct the measured Sagnac frequency of the large ring lasers, PR-1 and G-0. Dramatic improvements in the sensitivity of both lasers were achieved.
Most current laser gyroscopes use He-Ne plasma as the gain medium. This makes the devices fragile, the plasma creates UV light that degrades the cavity mirrors and the gas itself degrades over time. As a alternative, solid state materials might be used as the gain medium for the gyroscope. Both neodymium doped and erbium ytterbium co-doped phosphate glass lasers were constructed. Initially linear cavity designs were constructed to test the suitability of the gain media. Both laser systems employed longitudinal laser diode pumping. Thirty six perimeter ring lasers were then developed using both gain media. In both cases successful rotation sensing was achieved on a turntable which provided external rotation. For rotation rates between 0.1 and 0.85 rad/s, the gyroscope built using Er-Yb and Nd phosphate glass are superior to Nd:YAG (the only other material known to have been used in a continuous wave solid state gyroscope). This improvement is due to the use of thin heavily doped gain medium, which decreases the detrimental effect caused by gain gratings.
32
Egretzberger, Markus [Verfasser]. "Mathematical Modeling and Control of Micro Electromechanical Gyroscopes / Markus Egretzberger." Aachen : Shaker, 2010. http://d-nb.info/1080767010/34.
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Serrano, Diego Emilio. "Integrated inertial measurement units using silicon bulk-acoustic wave gyroscopes." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54283.
Full textAbstract:
This dissertation discusses the design, simulation and characterization of process-compatible accelerometers and gyroscopes for the implementation of multi-degree-of-freedom (multi-DOF) systems. All components presented herein were designed to operate under the same vacuum-sealed environment to facilitate batch fabrication and wafer-level packaging (WLP), enabling the development of small form-factor single-die inertial measurement units (IMUs). The high-aspect-ratio poly and single-crystal silicon (HARPSS) process flow was used to co-fabricate the devices that compose the system, enabling the implementation ultra-narrow capacitive gaps (< 300 nm) in thick device-layer substrates (40 um).
The presented gyroscopes were implemented as high-frequency BAW disk resonators operating in a mode-matched condition. A new technique to reduced dependencies on environmental stimuli such as temperature, vibration and shock was introduced. Novel decoupling springs were utilized to effectively isolate the gyros from their substrate, minimizing the effect that external sources of error have on offset and scale-factor. The substrate-decoupled (SD) BAW gyros were interfaced with a customized IC to achieve supreme random-vibration immunity (0.012 (deg/s)/g) and excellent rejection to shock (0.075 (deg/s)/g). With a scale factor of 800 uV/(deg/s), the complete SD-BAW gyro system attains a large full-scale range (2500 deg/s) with excellent linearity. The measured angle-random walk (ARW) of 0.36 deg/rthr and bias-instability of 10.5 deg/hr are dominated by the thermal and flicker noise of the IC, respectively. Additional measurements using external electronics show bias-instability values as low as 3.5 deg/hr.
To implement the final monolithic multi-DOF IMU, accelerometers were carefully designed to operate in the same vacuum environment required for the gyroscopes. Narrow capacitive gaps were used to adjust the accelerometer squeeze-film damping (SFD) levels, preventing an under-damped response. Robust simulation techniques were developed using finite-element analysis (FEA) tools to extract accurate values of SFD, which were then match with measured results. Ultra-small single proof-mass tri-axial accelerometers with Brownian-noise as low as 30 ug/rtHz were interfaced with front-end electronics exhibiting scale-factor values in the order of 5 to 10 mV/g and cross-axis sensitivities of less than 3% before any electronic compensation.
34
Royo, Serrano Daniel. "Development of a calibration procedure for gyroscopes in CubeSat missions." Thesis, Luleå tekniska universitet, Rymdteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-83278.
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Loveday, Philip Wayne. "Analysis and Compensation of Imperfection Effects in Piezoelectric Vibratory Gyroscopes." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/26231.
Full textAbstract:
Vibratory gyroscopes are inertial sensors, used to measure rotation rates in a number of applications. The performance of these sensors is limited by imperfections that occur during manufacture of the resonators. The effects of resonator imperfections, in piezoelectric vibratory gyroscopes, were studied.
Hamilton's principle and the Rayleigh-Ritz method provided an effective approach for modeling the coupled electromechanical dynamics of piezoelectric resonators. This method produced accurate results when applied to an imperfect piezoelectric vibrating cylinder gyroscope. The effects of elastic boundary conditions, on the dynamics of rotating thin-walled cylinders, were analyzed by an exact solution of the Flügge shell theory equations of motion. A range of stiffnesses in which the cylinder dynamics was sensitive to boundary stiffness variations was established. The support structure, of a cylinder used in a vibratory gyroscope, should be designed to have stiffness outside of this range. Variations in the piezoelectric material properties were investigated. A figure-of- merit was proposed which could be used to select an existing piezoceramic material or to optimize a new composition for use in vibratory gyroscopes.
The effects of displacement and velocity feedback on the resonator dynamics were analyzed. It was shown that displacement feedback could be used to eliminate the natural frequency errors, that occur during manufacture, of a typical piezoelectric vibrating cylinder gyroscope. The problem of designing the control system to reduce the effects of resonator imperfections was investigated. Averaged equations of motion, for a general resonator, were presented. These equations provided useful insight into the dynamics of the imperfect resonator and were used to motivate the control system functions. Two control schemes were investigated numerically and experimentally. It was shown that it is possible to completely suppress the first-order effects of resonator mass/stiffness imperfections. Damping imperfections, are not compensated by the control system and are believed to be the major source of residual error. Experiments performed on a piezoelectric vibrating cylinder gyroscope showed an order of magnitude improvement, in the zero-rate offset variation over a temperature range of 60°C, when the control systems were implemented.Ph. D.
36
Roth, Grant Flowers George T. "Simulation of the effects of acoustic noise on MEMS gyroscopes." Auburn, Ala., 2009. http://hdl.handle.net/10415/1773.
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SANTAGATA, ROSA. "Sub-nanometer length metrology for ultra-stable ring laser gyroscopes." Doctoral thesis, Rosa Santagata, 2015. http://hdl.handle.net/11365/1004514.
Full textAbstract:
Large-frame ring laser gyroscopes are extremely sensitive inertial detectors of rotational motion. When properly coupled to the ground, they provide precise measurements of the Earth rotation rate and give important informations to geodesy and geophysics. Recent advances in this technology led to consider the application of ring laser gyroscopes to fundamental physics. In this context is GINGER (Gyroscopes IN GEneral Relativity), a scientic proposal for testing General Relativity (local observation of the Lense-Thirring eect) with a ground-based array of ring laser gyroscopes. The experimental target is to locally measure the Earth rotation rate with a relative precision better than one part in 109, corresponding to an absolute rotational resolution of 10−14 rad/s. The main factor limiting the performances of the presently most stable ring laser gyroscopes is the uncontrolled deformation of their optical cavity, since instabilities in the cavity geometry introduce systematic errors in the rotational signal. Cavity geometry is typically kept stable by using monolithic frames made of ultra-low thermal expansion materials, and operating in very well isolated environments. An alternative approach is based on the active control of the shape in heterolithic cavities, by measuring and stabilizing the mirrors positions by means of laser-based length metrology.
The goal of this thesis is the development of a stabilization system based on interferometric length metrology, with a view to improve the sensitivity of the new generation square ring laser gyroscopes, going beyond the level achievable with passive methods. The main idea proposed in this work is to exploit the diagonal resonators formed by opposite cavity mirrors, and to use their lengths as observables to constraint, against an optical reference standard, residual deformation degrees of freedom of the square cavity.
As a rst step, a detailed model of the light propagation along the square cavity has been developed. This allowed us to quantify the eectiveness of the
v
xed length constraint of the diagonal resonators, and gave precise indications for the optimization strategy of the residual degrees of freedom.
The optical frequency reference is a helium neon laser stabilized to the iodine molecular absorption. Since the power emitted by this laser is of only 300 µW, an optical amplier, based on the injection locking of a 15 mW diode laser, has been developed to guarantee a proper signal to noise ratio in the interferometric absolute length measurements.
To stabilize the absolute lengths of the two diagonals, we proposed an original experimental method for the determination of both the optical resonance frequency and the free spectral range of each cavity. It is based on a triple-frequency modulation of the interrogating laser beam by electro-optic modulators. In a rst tabletop experiment, the method has been veried on two Fabry-Perot resonators that, composed by couples of spherical mirrors typically used in the He-Ne ring cavities, simulate the diagonals of a ring laser gyroscope on an optical bench. Here, the capability of setting equal the two lengths at the level of 500 nm, with residual uctuations only limited by the laser frequency noise, has been experimentally proved.
As a nal result, we have applied the developed method to lock the diagonal cavities lengths of GP2 ring laser gyroscope, a square cavity 1.6 m in side length dedicated to the interferometric control of the cavity geometry deformations, and fully set up at the INFN laboratories in Pisa in June 2015
38
Royle, Christopher Michael. "The mechanics of a micro-engineered gyroscope with piezoelectric actuation and sensing." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342484.
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Hope, Julian Charles. "A multi-sensor global navigation system for autonomous mobile robots." Thesis, University of Salford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284443.
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Plantier, Guy. "Analyse de la fonction de transfert de cavites gyrometriques acoustiques et de leurs transducteurs." Le Mans, 1991. http://www.theses.fr/1991LEMA1025.
Full textAbstract:
Lorsqu'une cavite acoustique remplie de gaz est mise en rotation, la force d'inertie de coriolis qui apparait, donne naissance (dans les couches limites visqueuses) a un couplage de modes acoustiques entre des modes principaux, entretenus a leur frequence de resonance par une source, et des modes secondaires orthogonaux. La mesure du taux de couplage entre ces modes, effectues a l'aide d'un microphone, permet de connaitre la vitesse de rotation. Un modele analytique precis, decrivant la structure du champ acoustique en fluide dissipatif dans une cavite en rotation, et prenant en compte notamment les diverses imperfections geometriques de la cavite, est propose. L'accord entre les resultats numeriques obtenus a l'issue d'une simulation, et les resultats experimentaux, a permis une avancee dans la conception de ce type de capteur. Par ailleurs, la miniaturisation du gyrometre, impose une taille reduite des microphones. Ils ont ete etudies dans le cadre de ce travail et realises par des techniques de micro-usinage du silicium dans un laboratoire specialise
41
Wong, Chor-fai Terence. "A gyroscopic approach to biped dynamic walking /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2073170X.
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Ahmadi, Amin. "Using MEMS inertial sensors to monitor and assess the performance of tennis serve." Thesis, Griffith University, 2010. http://hdl.handle.net/10072/366864.
Full textAbstract:
In recent years, there has been a growing interest in using Micro Electro Mechanical Systems or MEMS inertial sensors (accelerometers and gyroscopes) in monitoring the performance of athletes. Although it is in experimental stage, the main features of the MEMS technology including miniaturized, light, inexpensive, real time environment monitoring, close to real time feedback were appealing for athletes, coaches, sports scientistic and engineers. The use of the MEMS inertial sensors gained popularity due to the ability to measure the linear and rotational movement of the body segments without hindering the performance of athletes in many sporting activities including swimming, golf, soccer and cricket.
This thesis investigates the feasibility of using wearable inertial sensors to monitor and assess the tennis players’ first serve. Suitable high rate gyroscopes were not developed at the time of the PhD candidature, therefore a novel technique to simulate the behaviour of gyroscopes (virtual gyroscopes) to measure the angular velocity of body segments was developed. This virtual gyroscope can be attached on any segment to measure the angular velocity of that segment. The virtual gyroscope proposed in this dissertation allows for extraction of simulated angular velocity data from virtually any point on an athlete’s body or equipment. The novel one-dimensional virtual gyroscope can also measure angular velocities of any range, as opposed to real gyroscope sensors which suffer from limited measurement range.
This novel technique was applied to measure the upper arm internal rotation (one of the main contributors of the tennis serve with approximately 54% contribution) of athletes during the first tennis serve. Wrist flexion and shoulder rotation contribute approximately 31% and 10% respectively, were also measured using common vector based techniques. The results were verified against the real gyroscope and found to have a relationship and follow the same trends ((r = 0.9470, p < 0.0001), (r = 0.98914, p < 0.0001), (r = 0.8734, p < 0.0001) for the upper arm internal rotation, wrist flexion and shoulder rotation respectively).
Additionally, the use of accelerometers to detect the kinematic chain and virtual gyroscopes to assess the players from different skill levels was investigated. The peak values of the upper arm internal rotation, wrist flexion, and shoulder rotation just before impact were measured and used to categorize athletes in different levels from amateur to elite. It was shown that all the three parameters as well as the racquet head speed increased as the level of proficiency of the subjects increased. A line ( ) was fit to the scatter data containing the upper arm internal rotation, wrist flexion, and racquet head speed. The fit line is a function of upper arm rotation and wrist flexion. It was shown that the fit line can be used as a potential skill improvement tool to provide feedback on which variables (upper arm internal rotation, wrist flexion or shoulder rotation) needed to be improved. Therefore, it is envisaged that gyroscope sensors could be used for skill assessment and skill improvement for a first tennis serve. These results have great potential benefit for athletes to use non-invasive wearable inertial sensors to monitor and enhance their performance during training sessions on the tennis court.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Information and Communication Technology
Science, Environment, Engineering and Technology
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Uppalapati, Balaadithya. "Design and Analysis of Wafer-Level Vacuum-Encapsulated Disk Resonator Gyroscope Using a Commercial MEMS Process." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1510764485530995.
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Riedinger, Christophe. "Proposition of a new FDTD (Finite Difference Time Domain) algorithm for modelling a rotating Sagnac gyroscope and its applications to the reduction of perturbations." Université Louis Pasteur (Strasbourg) (1971-2008), 2007. http://www.theses.fr/2007STR13217.
Full textAbstract:
Proposition of a new FDTD (Finite Difference Time Domain) algorithm for modelling a rotating Sagnac gyroscope and its applications to the reduction of perturbations [. . . ]Proposition d'un nouvel algorithme FDTD (Finite Difference Time Domain) simulant un gyroscope Sagnac en rotation : application à la réduction des perturbations [. . . ]
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Renko, Zafiarisoa Dolor. "Synthèse totale de porphyrines protégées sur leurs deux faces (Porphyrines "Gyroscopes")." Paris 6, 1986. http://www.theses.fr/1986PA066274.
Full textAbstract:
La synthèse d'une nouvelle génération de porphyrines protégées sur leurs deux faces a été réalisée. Il s'agit d'un dérivé d'une octamethylporphyrine substituée en ses positions méso alpha et gamma par deux groupes phényles eux-mêmes fonctionnalises en position ortho et ortho par des anses peptidiques d'acides aminés optiquement actifs. L'une des anses comporte une pyridine. La synthèse totale de cette porphyrine a été effectuée en vue d'obtenir de nouveaux modèles d'hémoprotéines et de nouveaux catalyseurs d'époxydation asymétrique.
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Renko, Zafiarisoa Dolor. "Synthèse totale de porphyrines protégées sur leurs deux faces, porphyrines "gyroscopes"." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37600711z.
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Nagabhushan, Vivek. "Development of control moment gyroscopes for attitude control of small satellites." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0025032.
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Kassalias, Ioannis. "Attitude determination for the three-axis spacecraft simulator (TASS) by application of particle filtering techniques." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Jun%5FKassalias.pdf.
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Dalal, Milap. "Low noise, low power interface circuits and systems for high frequency resonant micro-gyroscopes." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44861.
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Today's state-of-the-art rate vibratory gyroscopes use a large proof mass that vibrates at a low resonance frequency (3-30 kHz), a condition that creates a performance tradeoff in which the gyroscope can either offer large bandwidth or high resolution, but not both. This tradeoff led to the development of the capacitive bulk acoustic wave (BAW) silicon disk gyroscope, a new class of micromachined rate vibratory gyroscopes operating in the frequency range of 1-10MHz with high device bandwidth and shock/vibration tolerance. By scaling the frequency, BAW gyroscopes can provide low mechanical noise without sacrificing the high bandwidth performance needed for most commercial applications. The drive loop of the BAW gyroscope can also be exploited as a timing device that can be integrated in existing commercial systems to provide competitive clock performance to the state-of-the-art using less area and power.
This dissertation discusses the design and implementation of a CMOS ASIC architecture that interfaces with a high-Q, wide-bandwidth BAW gyroscope and the challenges associated with optimizing the noise performance to achieve navigation-grade levels of sensitivity as the frequency is scaled into the MHz regime. Mathematical models are derived to describe the operation of the sensor and are used to generate equivalent electrical circuit models of the gyroscope. A design strategy is then outlined for the ASIC to optimize the drive loop and sense channel for power and noise, and steps toward reducing this noise as the system is pushed to navigation-grade performance are presented that maintain optimum system power consumption.
After analyzing the BAW gyroscope and identifying a strategy for developing the drive and sense interface circuitry, a complete fully-differential ASIC is designed in 0.18μm CMOS to interface with a bulk acoustic wave (BAW) disk gyroscope. As an oscillator, the gyroscope provides an uncompensated clock signal at ~9.64 MHz with a temperature sensitivity of -27 ppm/°C and phase noise of -104 dBc at 1 kHz from carrier. When the complete ASIC is interfaced with the gyroscope, the sensor shows a measured rate sensitivity of 1.15 mV/o/s with an open-loop bandwidth of 280 Hz and a bias instability of 0.095 o/s, suitable for the rate-grade performance commonly required for commercial and consumer electronics applications. The system is recorded to have a total power of 1.6 mW and a total area of 0.64 mm2.
Following the design of the interface ASIC, this dissertation investigates in further detail the requirements for designing and optimizing charge pumps for capacitive MEMS devices. Basic charge pump design is outlined, followed by an overview of techniques that can be used to generate larger polarization voltages from the ASIC. Lastly, an alternate measurement technique for measuring the rotation rate of the gyroscope is discussed. This technique is based on the phase-shift modulation of the gyroscope output signal when the device is driven with two orthogonal signal inputs and can be easily modified to provide either linear scale factor measurement or a linear calibration curve that can be used to track and adjust the variation of the sensor scale factor over time.
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Gaponov, Dmitry. "Propriétés optiques de fibres optiques microstructurées et laser à fibre de Bragg à grande aire modale." Limoges, 2008. http://aurore.unilim.fr/theses/nxfile/default/2af9d018-b039-4465-886e-0261ba1e73f3/blobholder:0/2008LIMO4067.pdf.
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De nos jours, nous observons une augmentation constante de la quantité de publications liées aux fibres microstructurées (MOFs). Bien que les aspects fondamentaux de leurs propriétés soient souvent éludés, leurs applications sont attrayantes pour de nombreux domaines de la science et la technologie en raison de leurs propriétés optiques uniques. Mon travail est consacré, d'une part à l'analyse comparative de certaines MOF bien connues à l'aide de différentes méthodes numériques et d'autre part, à la création expérimentale d'un laser à fibre monomode à grande aire modale (LMA) basé sur une fibre à bande photonique 1-D. Au cours de l'étude théorique, nous avons porté une attention particulière à l'étude de la structure de gaine. Nous avons en particulier montré le rôle de la réflexion radiale du champ sur l'interface silice polymère dans la hiérarchie des modes pour des fibres à cœur creux ou plein. Dans la partie expérimentale, nous avons étudié des fibres de Bragg dopées à l'ytterbium. Nous avons obtenu, pour la première fois, l'émission d'un faisceau monomode et démontré l'excellente résistance aux pertes par courbure de ce type de fibre en régime d'oscillation laserNowadays we observe a constant increasing of the amount of publications connected with Micro-structured Optical Fibers (MOFs). Nevertheless the unclear physical questions are still remaining in this field. From the other hand, applying of such structures is attractive in different fields of science and technology due to their unique optical properties. Our work is devoted to the theoretical analysis of some of the basic MOF types and to the experimental creation of fiber laser based on large mode area (LMA) 1-D photonic bandgap fiber (i. E. Bragg Fiber, BF). In the experimental part we investigated the Yb-doped LMA BF. We created a fiber laser based on this fiber with pumping into the cladding. We obtained the efficient singlemode lasing with low bend sensitivity, to the best of our knowledge, for the first time in such type of fibers