A superconducting gyroscope to test Einstein's general theory of relativity
Everitt, C. W. F.
1978-01-01
Schiff (1960) proposed a new test of general relativity based on measuring the precessions of the spin axes of gyroscopes in earth orbit. Since 1963 a Stanford research team has been developing an experiment to measure the two effects calculated by Schiff. The gyroscope consists of a uniform sphere of fused quartz 38 mm in diameter, coated with superconductor, electrically suspended and spinning at about 170 Hz in vacuum. The paper describes the proposed flight apparatus and the current state of development of the gyroscope, including techniques for manufacturing and measuring the gyro rotor and housing, generating ultralow magnetic fields, and mechanizing the readout.
Relative Pose Estimation Algorithm with Gyroscope Sensor
Shanshan Wei
2016-01-01
Full Text Available This paper proposes a novel vision and inertial fusion algorithm S2fM (Simplified Structure from Motion for camera relative pose estimation. Different from current existing algorithms, our algorithm estimates rotation parameter and translation parameter separately. S2fM employs gyroscopes to estimate camera rotation parameter, which is later fused with the image data to estimate camera translation parameter. Our contributions are in two aspects. (1 Under the circumstance that no inertial sensor can estimate accurately enough translation parameter, we propose a translation estimation algorithm by fusing gyroscope sensor and image data. (2 Our S2fM algorithm is efficient and suitable for smart devices. Experimental results validate efficiency of the proposed S2fM algorithm.
Gyroscope precession in special and general relativity from basic principles
Jonsson, Rickard M.
2007-05-01
In special relativity a gyroscope that is suspended in a torque-free manner will precess as it is moved along a curved path relative to an inertial frame S. We explain this effect, which is known as Thomas precession, by considering a real grid that moves along with the gyroscope, and that by definition is not rotating as observed from its own momentary inertial rest frame. From the basic properties of the Lorentz transformation we deduce how the form and rotation of the grid (and hence the gyroscope) will evolve relative to S. As an intermediate step we consider how the grid would appear if it were not length contracted along the direction of motion. We show that the uncontracted grid obeys a simple law of rotation. This law simplifies the analysis of spin precession compared to more traditional approaches based on Fermi transport. We also consider gyroscope precession relative to an accelerated reference frame and show that there are extra precession effects that can be explained in a way analogous to the Thomas precession. Although fully relativistically correct, the entire analysis is carried out using three-vectors. By using the equivalence principle the formalism can also be applied to static spacetimes in general relativity. As an example, we calculate the precession of a gyroscope orbiting a static black hole.
Analysis and testing of gyroscope performance for the Gravity Probe B relativity mission
Ohshima, Yoshimi
2000-11-01
This dissertation describes the analysis and experimental testing of the performance of electrostatically suspended vacuum gyroscopes (ESVG) designed for the Gravity Probe B Relativity Experiment (GP-B). The GP-B mission is a satellite-based gyroscope experiment currently under joint development by NASA and Stanford University. It is designed to test two predictions of Einstein's General Theory of Relativity: the geodetic effect and the frame-dragging effect. They are predicted to be 6.6 and 0.042 arc-sec/year, respectively, for a planned circular polar orbit. The primary goal of the GP-B mission is to measure the geodetic effect to better than 0.01%, and the frame-dragging effect to better than 1%. In order to achieve this goal, the non-relativistic drift rate of the gyroscope must be less than 0.3 milli-arc-sec/year. Presented is the analysis of the part of the Newtonian torque on the gyroscope rotor that is due to the electrostatic support, estimation of the science-mission drift rate, and experimental validation of the theoretical torque modeling. The analysis of the electrostatic torque indicates that the torque depends on both the close-to-perfect rotor shape with very minor manufacturing asphericity, and the voltage applied to the electrodes. To estimate the science-mission drift rate, we used the measured asphericity of an existing rotor that was below flight quality. Throughout the analysis, the estimated drift rate of the gyroscope induced by the non-relativistic effect was less than the maximum allowed drift rate of 0.3 milli-arc-sec/year for this effect. This result is gratifying because the actual flight rotors will exhibit a much lower non-relativistic drift rate. In the laboratory, parameters that characterize the electrostatic torque were measured by changing the voltages applied to the electrodes and the position of the gyroscope rotor in its housing cavity. The results match well with the theoretical expectations, confirming the validity of the
Unger, Glenn; Kaufman, David M.; Krainak, Michael; Sanders, Glenn; Taylor, Bill; Schulze, Norman R.
1993-01-01
A technology experiment on the X-ray Timing Explorer spacecraft to determine the feasibility of Interferometric Fiber Optic Gyroscopes for space flight navigation is described. The experiment consists of placing a medium grade fiber optic gyroscope in parallel with the spacecraft's inertial reference unit. The performance of the fiber optic gyroscope will be monitored and compared to the primary mechanical gyroscope's performance throughout the two-year mission life.
Hoots, F. R.; Fitzpatrick, P. M.
1979-01-01
The classical Poisson equations of rotational motion are used to study the attitude motions of an earth orbiting, rapidly spinning gyroscope perturbed by the effects of general relativity (Einstein theory). The center of mass of the gyroscope is assumed to move about a rotating oblate earth in an evolving elliptic orbit which includes all first-order oblateness effects produced by the earth. A method of averaging is used to obtain a transformation of variables, for the nonresonance case, which significantly simplifies the Poisson differential equations of motion of the gyroscope. Long-term solutions are obtained by an exact analytical integration of the simplified transformed equations. These solutions may be used to predict both the orientation of the gyroscope and the motion of its rotational angular momentum vector as viewed from its center of mass. The results are valid for all eccentricities and all inclinations not near the critical inclination.
The Initial Flight Calibration of the Gyroscopes for the Relativity Mission, Gravity Probe B
Buchman, S.; Bencze, W. J.; Brumley, R. W.; Muhlfelder, B.
The Relativity Mission, Gravity Probe B (GP-B), uses four redundant high precision gyroscopes for measuring the relativistic precessions of the frame of reference in a 640 km polar orbit. The two precessions to be measured are predicted in General Relativity to be the geodetic effect, 6.6 arcsec/year, and the frame dragging effect, 0.042 arcsec/year. The principal performance requirement for the gyroscopes is an accuracy capability of better than 0.3 marcsec/year. Results from more than 120,000 hours of gyroscope operation, testing on simulators, and analysis indicate that the residual Newtonian drift will be about 0.05 marcsec/year for a supported gyroscope and 0.01 marcsec/year for an unsupported gyroscope in a fully inertial orbit. Further disturbance reduction is achievable by optimizing the preload suspension voltage using measured flight parameters. Consistent with the presently scheduled launch of the Gravity Probe on April 17 2004, preliminary results from the initial testing, calibration, and spin-up of the gyroscopes will be presented.
Buchman, Saps; Everitt, Francis; Parkinson, Brad; Turneaure, John; MacKeiser; Taber, Mike; Bardas, Doron; Lockhart, Jim; Muhlfelder, Barry; Mester, John; Xiao, Yueming; Gutt, Gregory; Gill, Dale; Brumley, Robert; Di Donna, Brian
1996-11-01
The Gravity Probe B relativity mission experiment is designed to measure the frame dragging and geodetic relativistic precessions in a 650 km polar orbit. We describe some of the advanced experimental techniques used to achieve the required gyroscope accuracy of between 0.05 and 0264-9381/13/11A/026/img1. The subjects discussed are: (i) the development of high-precision gyroscopes with drift rates of less than 0264-9381/13/11A/026/img2, (ii) a low-temperature bake-out procedure resulting in a helium pressure of less than 0264-9381/13/11A/026/img3 at 2.5 K, (iii) a read-out system using DC SQUID magnetometers with a noise figure of 0264-9381/13/11A/026/img4 at 5 mHz and (iv) AC and DC magnetic shielding techniques which produce an AC attenuation factor in excess of 0264-9381/13/11A/026/img5 and a residual DC field of less than 0264-9381/13/11A/026/img6.
Bencze, W. J.; Eglington, M. E.; Brumley, R. W.; Buchman, S.
Presented here is a hybrid digital/analog electrostatic suspension control system for the NASA/Stanford University Gravity Probe B Relativity Mission’s science gyroscopes. An adaptive LQE algorithm, called Authority-on-Demand (AOD), has been developed to meet the high dynamic range requirements for mission’s electrostatic suspension, while minimizing suspension induced torques on the rotor. AOD is novel because it uses plant state estimates, rather than plant parameter estimates, as inputs for adaptation. In addition minimizing disturbance torques on the gyroscope, this suspension system can also maximize and control disturbances torques to perform a post spin-up alignment of the gyroscope spin axes. A backup all-analog proportional-derivative (PD) controller subsystem is provided to maintain control of the rotor in the event of computer faults/radiation induced upsets. A precision mechanical simulation of the gyroscope’s capacitive interface and dynamic response is used to verify performance of the overall system.
Measuring general relativity effects in a terrestrial lab by means of laser gyroscopes
Beverini, N; Beghi, A; Belfi, J; Bouhadef, B; Calamai, M; Carelli, G; Cuccato, D; Di Virgilio, A; Maccioni, E; Ortolan, A; Porzio, A; Santagata, R; Solimeno, S; Tartaglia, A
2013-01-01
GINGER is a proposed tridimensional array of laser gyroscopes with the aim of measuring the Lense-Thirring effect, predicted by the General Relativity theory, in a terrestrial laboratory environment. We discuss the required accuracy, the methods to achieve it, and the preliminary experimental work in this direction.
Local spacetime effects on gyroscope systems
Wohlfarth, Mattias N R
2012-01-01
We give a precise theoretical description of initially aligned sets of orthogonal gyroscopes which are transported along different paths from some initial point to the same final point in spacetime. These gyroscope systems can be used to synchronize separated observers' spatial frames by free fall along timelike geodesics. We find that initially aligned gyroscope systems, or spatial frames, lose their synchronization due to the curvature of spacetime and their relative motion. On the basis of our results we propose a simple experiment which enables observers to determine locally whether their spacetime is described by a rotating Kerr or a non-rotating Schwarzschild metric.
Local spacetime effects on gyroscope systems
Wohlfarth, Mattias N. R.; Pfeifer, Christian
2013-01-01
We give a precise theoretical description of initially aligned sets of orthogonal gyroscopes which are transported along different paths from some initial point to the same final point in spacetime. These gyroscope systems can be used to synchronize separated observers’ spatial frames by free fall along timelike geodesics. We find that initially aligned gyroscope systems, or spatial frames, lose their synchronization due to the curvature of spacetime and their relative motion. On the basis of our results we propose a simple experiment that enables observers to determine locally whether their spacetime is described by a rotating Kerr or a nonrotating Schwarzschild metric.
Range, Shannon K'doah; Mullins, Jennifer
This teaching guide introduces a relativity gyroscope experiment aiming to test two unverified predictions of Albert Einstein's general theory of relativity. An introduction to the theory includes the following sections: (1) "Spacetime, Curved Spacetime, and Frame-Dragging"; (2) "'Seeing' Spacetime with Gyroscopes"; (3)…
Microelectromechanical gyroscope
Garcia, Ernest J.
1999-01-01
A gyroscope powered by an engine, all fabricated on a common substrate in the form of an integrated circuit. Preferably, both the gyroscope and the engine are fabricated in the micrometer domain, although in some embodiments of the present invention, the gyroscope can be fabricated in the millimeter domain. The engine disclosed herein provides torque to the gyroscope rotor for continuous rotation at varying speeds and direction. The present invention is preferably fabricated of polysilicon or other suitable materials on a single wafer using surface micromachining batch fabrication techniques or millimachining techniques that are well known in the art. Fabrication of the present invention is preferably accomplished without the need for assembly of multiple wafers which require alignment and bonding, and without piece-part assembly.
Gravity Probe B Gyroscope Rotor
2003-01-01
The Gravity Probe B (GP-B) is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. This photograph is a close up of a niobium-coated gyroscope motor and its housing halves. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. Launched April 20, 2004 , the GP-B program was managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Don Harley.)
Online camera-gyroscope autocalibration for cell phones.
Jia, Chao; Evans, Brian L
2014-12-01
The gyroscope is playing a key role in helping estimate 3D camera rotation for various vision applications on cell phones, including video stabilization and feature tracking. Successful fusion of gyroscope and camera data requires that the camera, gyroscope, and their relative pose to be calibrated. In addition, the timestamps of gyroscope readings and video frames are usually not well synchronized. Previous paper performed camera-gyroscope calibration and synchronization offline after the entire video sequence has been captured with restrictions on the camera motion, which is unnecessarily restrictive for everyday users to run apps that directly use the gyroscope. In this paper, we propose an online method that estimates all the necessary parameters, whereas a user is capturing video. Our contributions are: 1) simultaneous online camera self-calibration and camera-gyroscope calibration based on an implicit extended Kalman filter and 2) generalization of the multiple-view coplanarity constraint on camera rotation in a rolling shutter camera model for cell phones. The proposed method is able to estimate the needed calibration and synchronization parameters online with all kinds of camera motion and can be embedded in gyro-aided applications, such as video stabilization and feature tracking. Both Monte Carlo simulation and cell phone experiments show that the proposed online calibration and synchronization method converge fast to the ground truth values.
Precise laser gyroscope for autonomous inertial navigation
Kuznetsov, A G; Molchanov, A V; Izmailov, E A [Joint Stock Company ' Moscow Institute of Electromechanics and Automatics' , Moscow (Russian Federation); Chirkin, M V [Ryazan State Radio Engineering University (Russian Federation)
2015-01-31
Requirements to gyroscopes of strapdown inertial navigation systems for aircraft application are formulated. The construction of a ring helium – neon laser designed for autonomous navigation is described. The processes that determine the laser service life and the relation between the random error of the angular velocity measurement and the surface relief features of the cavity mirrors are analysed. The results of modelling one of the promising approaches to processing the laser gyroscope signals are presented. (laser gyroscopes)
The confrontation between general relativity and experiment
Clifford M Will
2004-10-01
We review the experimental evidence for Einstein's general relativity. Tests of the Einstein equivalence principle support the postulates of curved space-time and bound variations of fundamental constants in space and time, while solar system experiments strongly confirm weak-field general relativity. The binary pulsar provides tests of gravitational wave damping and of strong-field general relativity. Future experiments, such as the gravity probe B gyroscope experiment, a satellite test of the equivalence principle, and tests of gravity at short distance to look for extra spatial dimensions could further constrain alternatives to general relativity. Laser Interferometric Gravitational Wave Observatories on Earth and in space may provide new tests of scalar–tensor gravity and graviton-mass theories via the properties of gravitational waves.
GINGER (Gyroscopes IN General Relativity), a ring lasers array to measure the Lense-Thirring effect
Di Virgilio, Angela D. V.
The purpose of the GINGER is to perform the first test of general relativity (not considering the gravitational redshift measurements) in a terrestrial laboratory, using light as a probe. The experiment will complement the ones in space, performed or under way, with an entirely different technique and at a far lower cost. The methodology is based on ring-lasers, which are extremely accurate rotation sensors and can not only sense purely kinematical rotations (Sagnac effect accounting for the Earth rotation, polar motion of the terrestrial axis, local rotational movements of the laboratory due to the Earth crust dynamics...), but also general relativistic contributions such as the de Sitter effect (coupling between the gravito-electric field of the earth and the kinematical rotation) and the Lense-Thirring effect (inertial frame dragging due to the angular momentum of the earth). In order to reveal the latter effects, ring-laser response must be improved to be able to measure the effective rotation vector (kinematic plus GR terms) with an accuracy of 1 part in 109 or better. This is a challenging technological aspect, which however has been accurately taken into account by designing a system of ring lasers that will be implemented in this project. A ring laser have been installed inside the underground laboratory of GranSasso, with the purpose to see if an underground location is the right choice for GINGER. The apparatus and the preliminary results will be discussed.
'It Has to Go Down A Little, In Order to Go Around'- Following Feynman on the Gyroscope
Kostov, Svilen; Hammer, Daniel
2010-01-01
In this paper we show that with the help of accessible, teaching quality equipment, some interesting details of the motion of a gyroscope, typically overlooked in introductory courses, can be measured and compared to theory. We begin by deriving a simple relation between the asymptotic dip angle of a gyroscope released from rest and its precession velocity. We then describe an experiment which measures these parameters. The data gives excellent agreement with the model. The idea for this proj...
The Gravity Probe B Gyroscopes
Buchman, Saps; Clarke, Bruce; Keiser, Mac; Gill, Dale; Marcelja, Frane; Brumley, Robert
2007-04-01
The four redundant GP-B electrostatically suspended gyroscopes measure the orientation of the local inertial frame of reference as influenced by the spinning Earth. The GP-B gyros are designed to improve the drift performance of ground based instruments by a factor of about 10^6 or 0.3 milliarcsec/year. Four factors make possible this improvement: 1) low (10-11 m/s^2) acceleration environment provided by the drag free system, 2) averaging of suspension related torques provided by the roll of the spacecraft, 3) geometry of the sensors, and 4) low gas pressure environment. The gyros are fused quartz spheres of 19 mm radius, coated with 1.3 μm niobium, with a peak to valley surface uniformity of better than 1 ppm and a separation of centers of geometry and mass of better than 1 ppm of the radius. The gyroscopes were spun to ˜70 Hz and exhibited characteristic spin down times of 7000 to 25,700 years. The gyroscopes potential was maintained to within 15 mV of local ground (15 pC charge) using a fiber coupled mercury vapor lamp to produce UV photoemission at 254 nm. The system allowed charge management and measurement to 2 mV. We present engineering data of the gyroscope and UV systems, as well as novel technologies employed and lessons learned.
Azarova, V V; Golyaev, Yu D; Saveliev, I I [Open Joint-Stock Company M.F. Stel' makh Polyus Research Institute, Moscow (Russian Federation)
2015-02-28
The history of invention and development of Zeeman laser gyroscopes, specific features of their optical scheme and operation principle are described. The construction and element base of modern laser angular velocity sensors with Zeeman-based frequency biasing are considered. The problems and prospects of their development are discussed. (laser gyroscopes)
Model Design of Piezoelectric Micromachined Modal Gyroscope
Xiaojun Hu
2011-01-01
Full Text Available This paper reports a novel kind of solid-state microgyroscope, which is called piezoelectric micromachined modal gyroscope (PMMG. PMMG has large stiffness and robust resistance to shake and strike because there is no evident mass-spring component in its structure. This work focused on quantitative optimization of the gyroscope, which is still blank for such gyroscope. The modal analysis by the finite element method (FEM was firstly conducted. A set of quantitative indicators were developed to optimize the operation mode. By FEM, the harmonic analysis was conducted to find the way to efficiently actuate the operational mode needed. The optimal configuration of driving electrodes was obtained. At last, the Coriolis analysis was conducted to show the relation between angular velocity and differential output voltage by the Coriolis force under working condition. The results obtained in this paper provide theoretical basis for realizing this novel kind of micromachined gyroscope.
Reflection-induced bias error in an air-core photonic bandgap fiber optic gyroscope.
Zhang, Zuchen; Xu, Xiaobin; Zhang, Zhihao; Song, Ningfang; Zhang, Chunxi
2016-01-15
Analysis of the bias error induced by reflections in an air-core photonic bandgap fiber gyroscope is performed by both simulation and experiment. The bias error is sinusoidally periodic under modulation, and its intensity is related to the relative positions of the reflection points. A simple and effective method for the suppression of the error is proposed, and it has been verified experimentally.
Aerodynamic Drag and Gyroscopic Stability
Courtney, Elya R
2013-01-01
This paper describes the effects on aerodynamic drag of rifle bullets as the gyroscopic stability is lowered from 1.3 to 1.0. It is well known that a bullet can tumble for stability less than 1.0. The Sierra Loading Manuals (4th and 5th Editions) have previously reported that ballistic coefficient decreases significantly as gyroscopic stability, Sg, is lowered below 1.3. These observations are further confirmed by the experiments reported here. Measured ballistic coefficients were compared with gyroscopic stabilities computed using the Miller Twist Rule for nearly solid metal bullets with uniform density and computed using the Courtney-Miller formula for plastic-tipped bullets. The experiments reported here also demonstrate a decrease in aerodynamic drag near Sg = 1.23 +/- 0.02. It is hypothesized that this decrease in drag over a narrow band of Sg values is due to a rapid damping of coning motions (precession and nutation). Observation of this drag decrease at a consistent value of Sg demonstrates the relati...
Fiberless Optical Gyroscope Project
National Aeronautics and Space Administration — We propose a radical new approach for to the design and fabrication of a fiber-less Interferometric Optical Gyroscope (IOG) that enables the production of a very...
Fiberless Optical Gyroscope Project
National Aeronautics and Space Administration — We propose a radical new approach for to the design and fabrication of a fiber-less Interferometric Optical Gyroscope (IOG) that enables the production of a...
V. N. Saxena
1983-04-01
Full Text Available Comparative study of mechanical, ring-laser and fibre-optic gyroscopes has been made. The single mode fibre-optic gyroscope having a large number of turns of the optical fibre in the spool, replacing He-Ne gas laser by a GaAs laser diode, there by reducing the noise level, and using fully integrated fibre-optics, works out to be the best in the final analysis, for safe navigation and homing of the guided missiles.
2015-07-15
Progress Report (ONR Award No. N00014-14-1-0804) Quantum Spin Gyroscope August 2014-July 2015 Report Type: Annual Report Primary Contact E-mail... Quantum Spin Gyroscope Grant/Contract Number: N00014-14-1-0804 Principal Investigator Name: Paola Cappellaro Program Manager: Richard Tommy Willis...required large volumes. Our project aims at overcoming these drawbacks by developing a novel solid-state quantum spin gyro- scope associated with the
Nuclear-Spin Gyroscope Based on an Atomic Co-Magnetometer
Romalis, Michael; Komack, Tom; Ghost, Rajat
2008-01-01
An experimental nuclear-spin gyroscope is based on an alkali-metal/noblegas co-magnetometer, which automatically cancels the effects of magnetic fields. Whereas the performances of prior nuclear-spin gyroscopes are limited by sensitivity to magnetic fields, this gyroscope is insensitive to magnetic fields and to other external perturbations. In addition, relative to prior nuclear-spin gyroscopes, this one exhibits greater sensitivity to rotation. There is commercial interest in development of small, highly sensitive gyroscopes. The present experimental device could be a prototype for development of nuclear spin gyroscopes suitable for navigation. In comparison with fiber-optic gyroscopes, these gyroscopes would draw less power and would be smaller, lighter, more sensitive, and less costly.
An Integrated MEMS Gyroscope Array with Higher Accuracy Output.
Chang, Honglong; Xue, Liang; Qin, Wei; Yuan, Guangmin; Yuan, Weizheng
2008-04-28
In this paper, an integrated MEMS gyroscope array method composed of two levels of optimal filtering was designed to improve the accuracy of gyroscopes. In the firstlevel filtering, several identical gyroscopes were combined through Kalman filtering into a single effective device, whose performance could surpass that of any individual sensor. The key of the performance improving lies in the optimal estimation of the random noise sources such as rate random walk and angular random walk for compensating the measurement values. Especially, the cross correlation between the noises from different gyroscopes of the same type was used to establish the system noise covariance matrix and the measurement noise covariance matrix for Kalman filtering to improve the performance further. Secondly, an integrated Kalman filter with six states was designed to further improve the accuracy with the aid of external sensors such as magnetometers and accelerometers in attitude determination. Experiments showed that three gyroscopes with a bias drift of 35 degree per hour could be combined into a virtual gyroscope with a drift of 1.07 degree per hour through the first-level filter, and the bias drift was reduced to 0.53 degree per hour after the second-level filtering. It proved that the proposed integrated MEMS gyroscope array is capable of improving the accuracy of the MEMS gyroscopes, which provides the possibility of using these low cost MEMS sensors in high-accuracy application areas.
An Integrated MEMS Gyroscope Array with Higher Accuracy Output
Weizheng Yuan
2008-04-01
Full Text Available In this paper, an integrated MEMS gyroscope array method composed of two levels of optimal filtering was designed to improve the accuracy of gyroscopes. In the firstlevel filtering, several identical gyroscopes were combined through Kalman filtering into a single effective device, whose performance could surpass that of any individual sensor. The key of the performance improving lies in the optimal estimation of the random noise sources such as rate random walk and angular random walk for compensating the measurement values. Especially, the cross correlation between the noises from different gyroscopes of the same type was used to establish the system noise covariance matrix and the measurement noise covariance matrix for Kalman filtering to improve the performance further. Secondly, an integrated Kalman filter with six states was designed to further improve the accuracy with the aid of external sensors such as magnetometers and accelerometers in attitude determination. Experiments showed that three gyroscopes with a bias drift of 35 degree per hour could be combined into a virtual gyroscope with a drift of 1.07 degree per hour through the first-level filter, and the bias drift was reduced to 0.53 degree per hour after the second-level filtering. It proved that the proposed integrated MEMS gyroscope array is capable of improving the accuracy of the MEMS gyroscopes, which provides the possibility of using these low cost MEMS sensors in high-accuracy application areas.
Instability of Gyroscopic Systems
Lancaster, Peter; Kliem, Wolfhard
1997-01-01
A conjecture of Renshaw and Mote concerning gyroscopic systems with parameters predicts the eigenvalue locus in the neighbourhood of a double zero eigenvalue. In the present paper this conjecture is reformulated in the language of generalized eigenvectors, angular splitting and analytic behaviour...
Temperature Experiment and Computer Simulation Analysis of Fiber Optical Gyroscope%光纤陀螺的温度实验与仿真分析
杨昌均; 冯志刚; 廖良斌; 杨宏源
2011-01-01
Thermally induced non reciprocity phase shift has affected working-accuracy of fiber optical gyroscope (FOG). By the analysis of this phase shift, the relationship of it and temperature characteristic (TC)in FOG were established. Based on it, the temperature experiment (TE)and computer simulation analysis (SA)have been carried on. The results show that SA of temperature distribution(TD)in FOG can be realized, and the way of TC and SA can help to clear up TC in FOG.%热致非互易相移的存在影响了光纤陀螺的工作精度.通过对热致非互易相移的分析,把握了该相移与光纤陀螺温度特性的关系.在此基础上,进行了光纤陀螺的温度实验与仿真分析.结果表明,仿真分析光纤陀螺的整体温度分布是可行的;温度实验与仿真分析相结合的办法有助于光纤陀螺温度特性的把握.
Electromagnetic fields and torque for a rotating gyroscope with a superconducting shield
Ebner, C.; Sung, C. C.
1975-01-01
In a proposed experiment, a measurement is to be made of the angular precession of a rotating superconducting gyroscope for the purpose of testing different general-relativity theories. For various reasons having to do with the design of the experiment, the superconducting shield surrounding the gyroscope is not spherically symmetric and produces a torque. There are two distinct features of the shield which lead to a torque on the gyroscope. First, its shape is a sphere intersected by a plane. If the angular momentum of the gyroscope is not parallel to the rotational symmetry axis of the shield, there is a torque which is calculated. Second, there are small holes in the spherical portion of the shield. The earth's field can penetrate through these holes and give an additional torque which is also calculated. In the actual experiment, these torques must be accurately known or made very small in order to obtain meaningful results. The present calculation is sufficiently general for application over a wide range of experimental design parameters.
Temperature compensation method using readout signals of ring laser gyroscope.
Li, Geng; Wang, Fei; Xiao, Guangzong; Wei, Guo; Zhang, Pengfei; Long, Xingwu
2015-05-18
Traditional compensation methods using temperature-related parameters have little effect when the ring laser gyroscope (RLG) bias changes rapidly. To solve this problem, a novel RLG bias temperature compensation method using readout signals is proposed in this paper. Combined with the least squares support vector machine (LS-SVM) algorithm, the novel method can improve the precision of the RLG bias. Experiments show that by utilizing the readout signals in the LS-SVM model, the RLG bias stability can be significantly raised compared to the original data. The novel method proposed in this paper is shown to be feasible, even when the RLG bias changes rapidly.
Modeling and Formulation of a Novel Microoptoelectromechanical Gyroscope
Bohua Sun
2008-01-01
Full Text Available This paper proposed a novel design of microgyroscope based on MEMS structures and optic interferometric microdisplacement measurement technique. The gyroscope consists of microvibrator and interferometric readout. Using Coriolis force, the vibrator transfers the system rotation into a forced vibration; the induced vibration can be sensed by the interferometric microdisplacement measurement system. The optic measurement system has two mirrors which will reflect two rays into a detector. The comprehensive studies on the formulation and analysis of the proposed gyroscope have been undertaken; two key sensor equations have been derived in the first time in the world: (1 relation between rotation and phase shift of light Δφ=(4πl0/λ+(8π/λ(xmaxQy/ωyΩ(tsin(ωdt, (2 relation between rotation and interferometric intensity of light I(t≈(8π/λ(xmaxQy/ωyΩ(tsin(ωdtsin(4πl0/λ. The comparison of the proposed gyroscope and well-know Sagnac formulation has been investigated; it shown that the proposed model is much better than Sagnac ones. The new model has finally get rid of needing very long fiber in the case of Sagnac gyroscope. The innovative model gives a new hope to fabricate high accurate and cheaper gyroscope. To date, the proposed gyroscope is the most accurate gyroscope.
The Gravity Probe B electrostatic gyroscope suspension system (GSS)
Bencze, W. J.; Brumley, R. W.; Eglington, M. L.; Hipkins, D. N.; Holmes, T. J.; Parkinson, B. W.; Ohshima, Y.; Everitt, C. W. F.
2015-11-01
A spaceflight electrostatic suspension system was developed for the Gravity Probe B (GP-B) Relativity Mission’s cryogenic electrostatic vacuum gyroscopes which serve as an indicator of the local inertial frame about Earth. The Gyroscope Suspension System (GSS) regulates the translational position of the gyroscope rotors within their housings, while (1) minimizing classical electrostatic torques on the gyroscope to preserve the instrument’s sensitivity to effects of General Relativity, (2) handling the effects of external forces on the space vehicle, (3) providing a means of precisely aligning the spin axis of the gyroscopes after spin-up, and (4) acting as an accelerometer as part of the spacecraft’s drag-free control system. The flight design was tested using an innovative, precision gyroscope simulator Testbed that could faithfully mimic the behavior of a physical gyroscope under all operational conditions, from ground test to science data collection. Four GSS systems were built, tested, and operated successfully aboard the GP-B spacecraft from launch in 2004 to the end of the mission in 2008.
'It Has to Go Down A Little, In Order to Go Around'- Following Feynman on the Gyroscope
Kostov, Svilen
2010-01-01
In this paper we show that with the help of accessible, teaching quality equipment, some interesting details of the motion of a gyroscope, typically overlooked in introductory courses, can be measured and compared to theory. We begin by deriving a simple relation between the asymptotic dip angle of a gyroscope released from rest and its precession velocity. We then describe an experiment which measures these parameters. The data gives excellent agreement with the model. The idea for this project was suggested by the discussion of gyroscopic motion in The Feynman Lectures on Physics. Feynman's conclusion (stated in colloquial terms and quoted in the title) is confirmed and, in addition, conservation of angular momentum, which underlies this effect, is quantitatively demonstrated.
`It Has to Go Down a Little, in Order to Go Around' -- Revisiting Feynman on the Gyroscope
Kostov, Svilen; Hammer, Daniel
2011-04-01
In this paper we show that with the help of accessible, teaching-quality equipment, some interesting and important details of the motion of a gyroscope, which are typically overlooked in introductory courses, can be measured and compared to theory. We begin by deriving a simple relation between the dip angle of a gyroscope released from rest and its precession velocity. We then describe an experiment that measures these parameters. The data are in excellent agreement with the theoretical prediction. The idea for this project was suggested by the discussion of gyroscopic motion in The Feynman Lectures on Physics. Feynman's (Fig. 1) conclusion (stated in colloquial language and quoted in the title) is confirmed and, in addition, conservation of angular momentum, which underlies this effect, is quantitatively demonstrated.
A precision closed-loop driving scheme of silicon micromachined vibratory gyroscope
Yang Bo; Zhou Bailing; Wang Shourong [Instrument Science and Engineering Department, Southeast University Nanjing 210096 (China)
2006-04-01
This paper describes a precision closed-loop driving scheme for Silicon Micromachined Vibratory Gyroscope (SMVG). It decouples the angle and gain of the selfoscillation- driven, optimizes the angle to reduce the relative difference between drive frequency and resonant frequency of the drive mode and achieves the closed-loop selfoscillation- driven by nonlinear relation between DC voltage using for control and drive force. The experiments show that the standard deviation of drive frequency is 0.009Hz, with relative drift 2.2ppm and the standard deviation of the amplitude is 0.0025mV, with relative drift 15ppm in one hour respectively. The closed-loop drive scheme improves the precision and stability of drive frequency and the amplitude of the gyroscope well. The paper analyses and tests the noise of the self-oscillation-driven. The result shows that the self-oscillation-driven has a rms noise below -100dB.
Advances in Gyroscope Technologies
Armenise, Mario N; Dell'Olio, Francesco; Passaro, Vittorio MN
2011-01-01
This monograph collects and critically reviews the main results obtained by the scientific community in gyroscope technologies research field. It describes architectures, design techniques and fabrication technology of angular rate sensors proposed in literature. MEMS, MOEMS, optical and mechanical technologies are discussed together with achievable performance. The book also considers future research trends aimed to cover special applications. The book is intended for researchers and Ph.D. students interested in modelling, design and fabrication of gyros. The book may be a useful education su
GYROSCOPIC MANAGEMENT AND GENERATION Y
Orhei Loredana
2012-12-01
Full Text Available In the professional field of business and management there is still little research done on the possibility if the Generation Y members (born between 1980 and 2000, which are the managers off the future, need a different approach in education and training to be prepared for the future. The authors will explain how a new didactical approach in business and management called â€œGyroscopic Managementâ€ can prepare these new managers to be of added value for the business. This specific approach was the start in 2007 of a specific (international HRQM Bachelor study programme at Arnhem Business School, HAN University in the Netherlands. During this study programme, students are confronting this specific training and didactical approach with characteristics as self-reliance, self-study, and Socratic dialogue, ethical and â€œgyroscopicâ€ management. The programme has a clear vision and mission and didactical approach that triggers the above-mentioned elements. The approach focuses on the need for development of specific competencies like â€œIntercultural adaptabilityâ€, â€œInternational business awarenessâ€ and â€œSocial entrepreneurshipâ€ as added to the existing competencies needed for a Bachelor level in business and management education. As researchers, lecturers and trainers, the authors used and researched this approach during many lectures, seminars, trainings and workshops in the last years at Universities in Romania and The Netherlands. The authors present the characteristics of the members of the new Y generation and relate them to main elements of gyroscopic management as practice and the results of this practice for students. For this, the authors did a so-called â€œGrounded action researchâ€, from 2009 until 2012, among students of business and management studies. Further, the research was supported by focus groups over the same period. The authors have the opinion that this research is
Vorticity, Gyroscopic precession, and Spin-Curvature Force
Liang, Wei Chieh; Lee, Si Chen
2012-01-01
In investigating the relation between vorticity and gyroscopic precession, we calculate the vorticity vector in Godel, Kerr, Lewis, Schwarzschild, Minkowski metric and find out the vorticity vector of the specific observers is the angular velocity of gyroscopic precession. Furthermore, considering space-time torsion will flip the vorticity and spin-curvature force to opposite sign. This result is very similar to the behavior of positive and negative helicity of quantum spin in Stern-Gerlach f...
Nuclear Magnetic Resonance Gyroscope
Larsen, Michael; Griffith, Robert; Bulatowicz, Michael
2014-03-01
The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This presentation will describe the operational principles, design basics, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.
Design of a Novel MEMS Gyroscope Array
Feng Sun; Wei Wang; Xiaoyong Lv
2013-01-01
This paper reports a novel four degree-of-freedom (DOF) MEMS vibratory gyroscope. A MEMS gyroscope array is then presented using the novel gyroscope unit. In the design of the proposed 4-DOF MEMS vibratory gyroscope, the elements of the drive-mode are set inside the whole gyroscope architecture, and the elements of sense-mode are set around the drive-mode, which thus makes it possible to combine several gyroscope units into a gyroscope array through sense-modes of all the units. The complete ...
Tuning of MEMS Gyroscope using Evolutionary Algorithm and "Switched Drive-Angle" Method
Keymeulen, Didier; Ferguson, Michael I.; Breuer, Luke; Peay, Chris; Oks, Boris; Cheng, Yen; Kim, Dennis; MacDonald, Eric; Foor, David; Terrile, Rich; Yee, Karl
2006-01-01
We propose a tuning method for Micro-Electro-Mechanical Systems (MEMS) gyroscopes based on evolutionary computation that has the capacity to efficiently increase the sensitivity of MEMS gyroscopes through tuning and, furthermore, to find the optimally tuned configuration for this state of increased sensitivity. We present the results of an experiment to determine the speed and efficiency of an evolutionary algorithm applied to electrostatic tuning of MEMS micro gyros. The MEMS gyro used in this experiment is a pyrex post resonator gyro (PRG) in a closed-loop control system. A measure of the quality of tuning is given by the difference in resonant frequencies, or frequency split, for the two orthogonal rocking axes. The current implementation of the closed-loop platform is able to measure and attain a relative stability in the sub-millihertz range, leading to a reduction of the frequency split to less than 100 mHz.
Gravitation experiments at Stanford. [using general relativity theory
Lipa, J. A.
1980-01-01
The experimental situation in post-Newtonian gravitation is briefly reviewed in order to reexamine the extent to which experiment supports or refutes general relativity. A description is given of the equivalence principle project, the gyroscope experiment, and the search for gravity waves. It is noted that even though some doubt has been cast on the value of the perihelion advance and the gravitational redshift as precise tests of general relativity in the past few years, many competing theories have been ruled out; in particular, the results from the Viking mission significantly reduce the credibility of the Brans-Dicke theory (Brans and Dicke, 1961). The dimensionless constant omega in this theory is now forced to exceed 50, while the value originally proposed was 6 (omega being infinity in general relativity). It is noted that the gyro experiment described is capable of putting much tighter limits on this parameter, and together with the other experiments in progress will help place gravitational theory on a firmer experimental footing.
Coriolis vibratory gyroscopes theory and design
Apostolyuk, Vladislav
2016-01-01
This book provides the latest theoretical analysis and design methodologies of different types of Coriolis vibratory gyroscopes (CVG). Together, the chapters analyze different types of sensitive element designs and their kinematics, derivation of motion equations, analysis of sensitive elements dynamics in modulated and demodulated signals, calculation and optimization of main performance characteristics, and signal processing and control. Essential aspects of numerical simulation of CVG using Simulink® are also covered. This is an ideal book for graduate students, researchers, and engineers working in fields that require gyroscope application, including but not limited to: inertial sensors and systems, automotive and consumer electronics, small unmanned aircraft control systems, personal mobile navigation systems and related software development, and augmented and virtual reality systems.
The development of micromachined gyroscope structure and circuitry technology.
Xia, Dunzhu; Yu, Cheng; Kong, Lun
2014-01-14
This review surveys micromachined gyroscope structure and circuitry technology. The principle of micromachined gyroscopes is first introduced. Then, different kinds of MEMS gyroscope structures, materials and fabrication technologies are illustrated. Micromachined gyroscopes are mainly categorized into micromachined vibrating gyroscopes (MVGs), piezoelectric vibrating gyroscopes (PVGs), surface acoustic wave (SAW) gyroscopes, bulk acoustic wave (BAW) gyroscopes, micromachined electrostatically suspended gyroscopes (MESGs), magnetically suspended gyroscopes (MSGs), micro fiber optic gyroscopes (MFOGs), micro fluid gyroscopes (MFGs), micro atom gyroscopes (MAGs), and special micromachined gyroscopes. Next, the control electronics of micromachined gyroscopes are analyzed. The control circuits are categorized into typical circuitry and special circuitry technologies. The typical circuitry technologies include typical analog circuitry and digital circuitry, while the special circuitry consists of sigma delta, mode matching, temperature/quadrature compensation and novel special technologies. Finally, the characteristics of various typical gyroscopes and their development tendency are discussed and investigated in detail.
The Development of Micromachined Gyroscope Structure and Circuitry Technology
Dunzhu Xia
2014-01-01
Full Text Available This review surveys micromachined gyroscope structure and circuitry technology. The principle of micromachined gyroscopes is first introduced. Then, different kinds of MEMS gyroscope structures, materials and fabrication technologies are illustrated. Micromachined gyroscopes are mainly categorized into micromachined vibrating gyroscopes (MVGs, piezoelectric vibrating gyroscopes (PVGs, surface acoustic wave (SAW gyroscopes, bulk acoustic wave (BAW gyroscopes, micromachined electrostatically suspended gyroscopes (MESGs, magnetically suspended gyroscopes (MSGs, micro fiber optic gyroscopes (MFOGs, micro fluid gyroscopes (MFGs, micro atom gyroscopes (MAGs, and special micromachined gyroscopes. Next, the control electronics of micromachined gyroscopes are analyzed. The control circuits are categorized into typical circuitry and special circuitry technologies. The typical circuitry technologies include typical analog circuitry and digital circuitry, while the special circuitry consists of sigma delta, mode matching, temperature/quadrature compensation and novel special technologies. Finally, the characteristics of various typical gyroscopes and their development tendency are discussed and investigated in detail.
The Development of Micromachined Gyroscope Structure and Circuitry Technology
Xia, Dunzhu; Yu, Cheng; Kong, Lun
2014-01-01
This review surveys micromachined gyroscope structure and circuitry technology. The principle of micromachined gyroscopes is first introduced. Then, different kinds of MEMS gyroscope structures, materials and fabrication technologies are illustrated. Micromachined gyroscopes are mainly categorized into micromachined vibrating gyroscopes (MVGs), piezoelectric vibrating gyroscopes (PVGs), surface acoustic wave (SAW) gyroscopes, bulk acoustic wave (BAW) gyroscopes, micromachined electrostatically suspended gyroscopes (MESGs), magnetically suspended gyroscopes (MSGs), micro fiber optic gyroscopes (MFOGs), micro fluid gyroscopes (MFGs), micro atom gyroscopes (MAGs), and special micromachined gyroscopes. Next, the control electronics of micromachined gyroscopes are analyzed. The control circuits are categorized into typical circuitry and special circuitry technologies. The typical circuitry technologies include typical analog circuitry and digital circuitry, while the special circuitry consists of sigma delta, mode matching, temperature/quadrature compensation and novel special technologies. Finally, the characteristics of various typical gyroscopes and their development tendency are discussed and investigated in detail. PMID:24424468
Smith, David D.
2015-01-01
Next-generation space missions are currently constrained by existing spacecraft navigation systems which are not fully autonomous. These systems suffer from accumulated dead-reckoning errors and must therefore rely on periodic corrections provided by supplementary technologies that depend on line-of-sight signals from Earth, satellites, or other celestial bodies for absolute attitude and position determination, which can be spoofed, incorrectly identified, occluded, obscured, attenuated, or insufficiently available. These dead-reckoning errors originate in the ring laser gyros themselves, which constitute inertial measurement units. Increasing the time for standalone spacecraft navigation therefore requires fundamental improvements in gyroscope technologies. One promising solution to enhance gyro sensitivity is to place an anomalous dispersion or fast light material inside the gyro cavity. The fast light essentially provides a positive feedback to the gyro response, resulting in a larger measured beat frequency for a given rotation rate as shown in figure 1. Game Changing Development has been investing in this idea through the Fast Light Optical Gyros (FLOG) project, a collaborative effort which began in FY 2013 between NASA Marshall Space Flight Center (MSFC), the U.S. Army Aviation and Missile Research, Development, and Engineering Center (AMRDEC), and Northwestern University. MSFC and AMRDEC are working on the development of a passive FLOG (PFLOG), while Northwestern is developing an active FLOG (AFLOG). The project has demonstrated new benchmarks in the state of the art for scale factor sensitivity enhancement. Recent results show cavity scale factor enhancements of approx.100 for passive cavities.
Stability Analysis of MEMS Gyroscope Dynamic Systems
M. Naser-Moghadasi; S. A. Olamaei; F. Setoudeh
2013-01-01
In this paper, the existence of a common quadratic Lyapunov function for stability analysis of MEMS Gyroscope dynamic systems has been studied then a new method based on stochastic stability of MEMS Gyroscope system has been proposed.
Selecting Aquifer Wells for Planned Gyroscopic Logging
Rohe, Michael James; Studley, Gregory Wayne
2002-04-01
surveying. Nineteen (19) of the 44 wells without magnetic deviation data were selected for the planned gyroscopic logging based on their location relative to facilities, site boundaries, and contaminant transport concerns. In total, 44 aquifer wells (25 with magnetic deviation data and 19 without) are recommended for planned gyroscopic logging.
Design of a Novel MEMS Gyroscope Array
Feng Sun
2013-01-01
Full Text Available This paper reports a novel four degree-of-freedom (DOF MEMS vibratory gyroscope. A MEMS gyroscope array is then presented using the novel gyroscope unit. In the design of the proposed 4-DOF MEMS vibratory gyroscope, the elements of the drive-mode are set inside the whole gyroscope architecture, and the elements of sense-mode are set around the drive-mode, which thus makes it possible to combine several gyroscope units into a gyroscope array through sense-modes of all the units. The complete 2-DOF vibratory structure is utilized in both the drive-mode and sense-mode of the gyroscope unit, thereby providing the desired bandwidth and inherent robustness. The gyroscope array combines several gyroscope units by using the unique detection mass, which will increase the gain of sense-mode and improve the sensitivity of the system. The simulation results demonstrate that, compared to a single gyroscope unit, the gain of gyroscope array (n = 6 is increased by about 8 dB; a 3 dB bandwidth of 100 Hz in sense-mode and 190 Hz in drive-mode are also provided. The bandwidths of both modes are highly matched with each other, providing a bandwidth of 100 Hz for the entire system, thus illustrating that it could satisfy the requirements in practical applications.
High performance MEMS micro-gyroscope
Bae, S. Y.; Hayworth, K. J.; Yee, K. Y.; Shcheglov, K.; Challoner, A. D.; Wiberg, D. V.
2002-01-01
This paper reports on JPL's on-going research into MEMS gyroscopes. This paper will describe the gyroscope's fabrication-methods, a new 8-electrode layout developed to improve performance, and performance statistics of a batch of six gyroscopes recently rate tested.
Design of a novel MEMS gyroscope array.
Wang, Wei; Lv, Xiaoyong; Sun, Feng
2013-01-28
This paper reports a novel four degree-of-freedom (DOF) MEMS vibratory gyroscope. A MEMS gyroscope array is then presented using the novel gyroscope unit. In the design of the proposed 4-DOF MEMS vibratory gyroscope, the elements of the drive-mode are set inside the whole gyroscope architecture, and the elements of sense-mode are set around the drive-mode, which thus makes it possible to combine several gyroscope units into a gyroscope array through sense-modes of all the units. The complete 2-DOF vibratory structure is utilized in both the drive-mode and sense-mode of the gyroscope unit, thereby providing the desired bandwidth and inherent robustness. The gyroscope array combines several gyroscope units by using the unique detection mass, which will increase the gain of sense-mode and improve the sensitivity of the system. The simulation results demonstrate that, compared to a single gyroscope unit, the gain of gyroscope array (n = 6) is increased by about 8 dB; a 3 dB bandwidth of 100 Hz in sense-mode and 190 Hz in drive-mode are also provided. The bandwidths of both modes are highly matched with each other, providing a bandwidth of 100 Hz for the entire system, thus illustrating that it could satisfy the requirements in practical applications.
Light-shift measurement and suppression in atomic spin gyroscope.
Fang, Jiancheng; Wan, Shuangai; Chen, Yao; Li, Rujie
2012-11-01
We present a method to determine and suppress the light shift in an atomic spin gyroscope. This method doesn't require additional drive source or frequency modulation, and it is based on the dynamics of an atomic spin gyroscope to determine a clean curve as a function of the frequency of the pump beam that predicts the zero light shift. We experimentally validate the method in a Cs-(129)Xe atomic spin gyroscope and verify the results through numerical simulations. This method can also be applied to an atomic spin magnetometer based on the spin-exchange relaxation-free exchange that experiences light shift. The method is useful for atomic spin devices because it can improve long-term performance and reduce the influence of the laser.
Controllable Dispersion in an Optical Laser Gyroscope
Wolfe, Owen; Du, Shuangli; Rochester, Simon; Budker, Dmitry; Novikova, Irina; Mikhailov, Eugeniy
2016-05-01
Optical gyroscopes use Sagnac interferometry to make precise measurements of angular velocity. Increased gyroscope sensitivity will allow for more accurate control of aerospace systems and allow for more precise measurements of the Earth's rotation. Severalfold improvements to optical gyroscope sensitivity were predicted for fast light regimes (ng gyroscope response via tuning the experimental parameters. Gyroscope sensitivity was shown to be dependent on several parameters including pump power, pump detunning, and vapor density. This work was supported by the NSF and Naval Air Warfare Center STTR program N68335-11-C-0428.
Rate Gyroscopic Wellbore Survey System
Sheng Limin
1997-01-01
@@ The rate gyroscopic wellbore survey system as a new type of survey instruments adopts the inertial-grade rate gyro and quartz flexible accelerometers to compose a gyrocompassing system, transiting data to surface instrument by single core cable. The azimuth, inclination and tool-face angle can be computed from these data by surface computer.
Vorticity, Gyroscopic precession, and Spin-Curvature Force
Liang, Wei Chieh
2012-01-01
In investigating the relation between vorticity and gyroscopic precession, we calculate the vorticity vector in Godel, Kerr, Lewis, Schwarzschild, Minkowski metric and find out the vorticity vector of the specific observers is the angular velocity of gyroscopic precession. Furthermore, considering space-time torsion will flip the vorticity and spin-curvature force to opposite sign. This result is very similar to the behavior of positive and negative helicity of quantum spin in Stern-Gerlach force. It implies that the inclusion of torsion will lead to analogous property of quantum spin even in classical treatment.
基于阵列技术的MEMS陀螺温度补偿方法%An Array Technique Based Method for Temperature Compensation of MEMS Gyroscopes
沈强; 刘洁瑜
2015-01-01
为了减少温度对MEMS陀螺测量精度的影响，提出了一种采用阵列技术的MEMS陀螺仪温度误差补偿新方法。该方法不需要进行温度测量，通过对多陀螺输出进行数据融合以消除温度对陀螺仪输出的影响，达到正确检测角速率的目的，简化了系统结构。采用遗传算法优化的BP神经网络来进行陀螺阵列数据的融合，抛开通常把零偏和标度因数分开建模补偿的思想，将两者统一进行补偿。实验结果表明，该方法能够大幅度降低温度造成的陀螺误差，从而满足工程应用需要。%In order to decrease temperature related errors in MEMS gyroscope, a novel method based on array technique is proposed for temperature compensation of the gyroscope. The advantage of this method is that it is not need to measure the temperature, in stead, data fusion of the output of several gyroscopes is used to reduce the influence of temperature, and the system structure is simplified. The BP neural network optimized by genetic algorithms is used in data fusion of the gyroscope data, which compensates the error of the output of gyroscopes directly, while the zero bias and scale factors are compensated separately in general. The results of the experiments show that the method proposed can significantly reduce the error of gyroscope caused by temperature, and thus can improve the accuracy.
Development of Vibrating Disc Piezoelectric Gyroscope
A.K. Singh
2004-07-01
Full Text Available The paper presents an indigenously developed vibrating disc piezoelectric gyroscope, in which both excitation and detection have been done through piezoelectric, using PZT-5H material. The gyroscope has been driven to resonant state by direct piezoelectric effect, using 20 V ac signal at 93 kHz, and the output has been detected by the reverse piezoelectric effect.The performance of this gyroscope has been tested with 3 microprocessor-controlled turntable, and the output of the gyroscope has been found" to be linearly proportional to the rotationspeed within a range ± 150 °/s. The sensitivity of the gyroscope is about 0.5 mV/°/s, which is comparable to that of other gyroscopes of similar category
GEC Ferranti piezo vibratory gyroscope
Nuttall, J. D.
1993-01-01
Prototypes of a piezo-electric vibratory angular rate transducer (gyroscope) (PVG) have been constructed and evaluated. The construction is on the lines suggested by Burdess. The sensitive element is a cylinder of radially poled piezo-electric ceramic. The cylinder is metallized inside and out, and the outer metallization is divided into eight electrodes. The metallization on the inside is earthed. A phase locked loop, using pairs of the electrodes, causes the cylinder to vibrate in one of its two fundamental, degenerate modes. In the presence of rotation, some of the vibration is coupled into the outer mode. This can be detected, or suppressed with a closed-up technique and provides a measure of rotation rate. The gyroscope provides a number of advantages over rotating mass and optical instruments: low size and mass, lower power consumption, potentially high reliability, potentially good dormancy, low cost and high maximum rate.
A novel ring vibrating gyroscope based on side piezo-electrodes
ZHOU Xin; WU Yu-lie; WU Xue-zhong; ZHANG Yong-meng; ZHENG Yu
2016-01-01
Solid-state wave gyroscope is one kind of high-performance vibrating gyroscopes. The present work develops a new type of solid-state wave gyroscope—a ring vibrating gyroscope driven by piezo-electrodes located on the sidewall of the structure. It has advantages of large vibrating amplitude, high energy conversion efficiency and compact structure. The working principle of the piezoelectric ring vibrating gyroscope is based on the inertia effect of the standing wave in the axisymmetric resonator caused by Coriolis force. The finite element method (FEM) analysis has been implemented to characterize the ring type resonator. The prototypal gyroscope was manufactured and has been trimmed by mechanical way. The harmonic response of the ring vibrating gyroscope has been tested. The resonating frequency of the ring type resonator is 3715.6 Hz and the frequency split of the two working modes before trimming was about 5 Hz and was reduced to sub-0.01 Hz after trimming procedure. The Q-factor of the ring type resonator was 2504. Then, the turntable experiment was implemented. The measured scale factor k is 9.24 mV/[(°)·s] and the full scale range of the gyroscope is larger than ±300 (°)/s.
Thermal MEMS gyroscope design and characteristics analysis
Zarei, Nilgoon
2013-01-01
Thermal MEMS gyroscope characteristics have been studied to optimize gyroscope performance. Different parameters such as gas properties, heaters power and switching frequency have been optimized to increase the device sensitivity. A new Thermal MEMS gyroscope model referred to as “Forced Convection MEMS Gyroscope” has been introduced. In this design the output signal has been increased by adding external force to the system. Parameter optimization to increase the device efficiency has also...
Design and analysis of a gyroscopically controlled micro air vehicle
Thorne, Christopher Everett
Much of the current research on micro air vehicle design relies on aerodynamic forces for attitude control. The aerodynamic environment in which micro air vehicles operate is characterized by a low Reynolds number and is not fully understood, resulting in decreased performance and efficiency when compared to large-scale vehicles. In this work, we propose a new rotary-wing micro air vehicle design that utilizes gyroscopic dynamics for attitude control. Unlike traditional micro air vehicles where attitude control moments are generated by aerodynamic control surfaces, the proposed vehicle will leverage the existing angular momentum of its rotating components to generate gyroscopic moments for controlling attitude. We explore this paradigm in an effort to reduce mechanical complexity that is inherent in blade pitch modulation mechanisms such as the swashplate, and to increase agility and possibly even efficiency when compared to state-of-the-art micro vertical-take-off-and-landing vehicles. The evolution of the mechanical design, including the evaluation of three prototypes that explore the use of gyroscopic attitude control, is presented along with a comprehensive dynamic and aerodynamic model of the third prototype. Two controllers that utilize gyroscopic moments are developed and tested in simulation. In addition, several experiments were performed using a VICON motion tracking system and off-board control. These results will also be presented.
Gravity Probe B Gyroscope Electrostatic Suspension System (GSS)
Bencze, William; Hipkins, David; Holmes, Tom; Buchman, Saps; Brumley, Robert
2007-04-01
Presented here is a hybrid digital/analog electrostatic suspension control system for the Gravity Probe B Relativity Mission's science gyroscopes. The chief challenge for this system is to operate over 8 orders of force magnitude while minimizing classical torques on the gyroscope. A novel, adaptive LQE digital control algorithm was developed to meet the high dynamic range requirements for rotor suspension, while minimizing suspension-induced torques. A set of three backup, all-analog proportional-derivative (PD) controllers were provided to maintain rotor centering in the event of computer faults during all phases of the mission. The capacitive position sensing system measured rotor position to a noise floor of 0.15 nm/Hz in the science band (5 - 30 mHz). In addition, this system also applied controlled torques to perform a post spin-up alignment of the gyroscope spin axes to within 10 arc-sec of a desired orientation, and measured the rotor charge to the 2 pC (2 mV) level. The GSS contributed to drag-free operation of the space vehicle by using one of the gyroscopes as an isolated, inertial proof mass and was able to resolve accelerations to the 10-12 g level. On-orbit performance of this system will be discussed in detail.
MEMS Gyroscopes Based on Acoustic Sagnac Effect
Yuanyuan Yu
2016-12-01
Full Text Available This paper reports on the design, fabrication and preliminary test results of a novel microelectromechanical systems (MEMS device—the acoustic gyroscope. The unique operating mechanism is based on the “acoustic version” of the Sagnac effect in fiber-optic gyros. The device measures the phase difference between two sound waves traveling in opposite directions, and correlates the signal to the angular velocity of the hosting frame. As sound travels significantly slower than light and develops a larger phase change within the same path length, the acoustic gyro can potentially outperform fiber-optic gyros in sensitivity and form factor. It also promises superior stability compared to vibratory MEMS gyros as the design contains no moving parts and is largely insensitive to mechanical stress or temperature. We have carried out systematic simulations and experiments, and developed a series of processes and design rules to implement the device.
Design and analysis of a novel virtual gyroscope with multi-gyroscope and accelerometer array
Luo, Zhang; Liu, Chaojun; Yu, Shuai; Zhang, Shengzhi; Liu, Sheng
2016-08-01
A new virtual gyroscope with multi-gyroscope and accelerometer array (MGAA) is proposed in this article for improving the performance of angular rate measurement. Outputs of the virtual gyroscope are obtained by merging the signals from gyroscopes and accelerometers through a novel Kalman filter, which intentionally takes the consideration of the MEMS gyroscope error model and kinematics theory of rigid body. A typical configuration of the virtual gyroscope, consisting of four accelerometers and three gyroscopes mounted on designated positions, is initiated to verify the feasibility of the virtual gyroscope with MGAA. Static test and dynamic test are performed subsequently to evaluate its performance. The angular random walk (ARW) and bias instability, two static performance parameters of gyroscope, are reduced from 0.019°/√s and 14.4°/h to 0.0074°/√s and 8.7°/h, respectively. The average root mean square error (RMSE) is reduced from 0.274°/s to 0.133°/s under dynamic test. Compared with the published multi-gyroscope array method, the virtual gyroscope proposed here has a better performance both in static and dynamic tests, with improvement factors of ARW and RMSE about 44.1% and 44.5% higher, respectively.
Impact of assembly on signal detection from thin-wall rotors of micro-gyroscopes
Hai Li
2014-03-01
Full Text Available The assembly of sealed hollow rotors, a key component in achieving liquid-levitated micro-gyroscopes, represents a significant challenge. The rotor is a thin-wall cylinder composed of materials that are only 100-μm thick. Furnace soldering and hand soldering are used to join the work pieces, but produce defects evident from deformations and surface roughness. Modeling and experiments show that the deformation is related to the temperature during assembly and the mode by which heat is applied to the components. Temperature affects the deformation through thermal stress and air pressure on the rotor, but the mode of heating creates a big difference. Surface deformation of the rotor alters the detecting capacitance and introduces uncertainty in detection sensitivity of the gyroscope. Experiments show that at 220°C, furnace soldering of rotors causes a great decrease in detection sensitivity, leading to a relative uncertainty of nearly 40%. In contrast, hand soldering leads to a relative uncertainty of about 5%. Spot heating of the rotor during assembly is much better than total heating as less thermal stress is generated and the air pressure difference is almost eliminated. Lowering the temperature is helpful to as long as the connection is sufficiently strengthened.
"It Has to Go down a Little, in Order to Go around"--Revisiting Feynman on the Gyroscope
Kostov, Svilen; Hammer, Daniel
2011-01-01
In this paper we show that with the help of accessible, teaching-quality equipment, some interesting and important details of the motion of a gyroscope, which are typically overlooked in introductory courses, can be measured and compared to theory. We begin by deriving a simple relation between the "dip angle" of a gyroscope released from rest and…
Nonlinear fiber gyroscope for quantum metrology
Luis, Alfredo; Rivas, Ángel
2016-01-01
We examine the performance of a nonlinear fiber gyroscope for improved signal detection beating the quantum limits of its linear counterparts. The performance is examined when the nonlinear gyroscope is illuminated by practical field states, such as coherent and quadrature squeezed states. This is compared with the case of more ideal probes such as photon-number states.
Design and Fabrication of a Micromechanical Gyroscope
1995-12-01
Background 2.1 Vibrating Gyroscopes In 1851 a French scientist named Leon Focault studied the earth’s rotation through the use of a large pendulum [11...Workshop, Ft. Lauderdale, FL, Feb. 1993, pp. 143-148. 9. A. Boxenhorn and P. Greiff , "A vibratory micromechanical gyroscope," in AIAA Guidance, Navigation
A Precise Bound for Gyroscopic Stabilization
Hryniv, Rostyslav; Kliem, Wolfhard; Lancaster, Peter;
1998-01-01
ABSTRACT: We consider gyroscopic systems $M\\ddot x(t) + hG\\dot x(t) + Kx(t) = 0$ where $M>0,\\;G^T=-G$, and $K......ABSTRACT: We consider gyroscopic systems $M\\ddot x(t) + hG\\dot x(t) + Kx(t) = 0$ where $M>0,\\;G^T=-G$, and $K...
Gyroscopic Motion: Show Me the Forces!
Kaplan, Harvey; Hirsch, Andrew
2014-01-01
Gyroscopes are frequently used in physics lecture demonstrations and in laboratory activities to teach students about rotational dynamics, namely, angular momentum and torque. Use of these powerful concepts makes it difficult for students to fully comprehend the mechanism that keeps the gyroscope from falling under the force of gravity. The…
Nonlinear fiber gyroscope for quantum metrology
Luis, Alfredo; Morales, Irene; Rivas, Ángel
2016-07-01
We examine the performance of a nonlinear fiber gyroscope for improved signal detection beating the quantum limits of its linear counterparts. The performance is examined when the nonlinear gyroscope is illuminated by practical field states, such as coherent and quadrature squeezed states. This is compared with the case of more ideal probes such as photon-number states.
The Gyroscope Sensor Test by Using Arduino Platform
Yi-Jen Mon
2015-06-01
Full Text Available Abstract The gyroscope has ability to get accurate data of motions for space of three dimensions such as axes of x y and z. Its applications are covered very widely such as in mobile phone consumer electronics etc. due to the robust sense abilities of direction and motion. In this paper it is used to get data from motion and these data are shown in window and LCD screen. The experiment results show that it has good performance.
On the Late Invention of the Gyroscope
Brecher, Kenneth
2012-03-01
The invention of the gyroscope is usually attributed to the French physicist Jean-Bernard-Leon Foucault in 1852. He certainly invented the word and also used his gyroscope to demonstrate the rotation of the Earth. However, the gyroscope was actually invented around 1812 by German physicist Johann Bohnenberger who called his device simply the ``machine''. Several others, including American physicist Walter R. Johnson (who called his apparatus the ``rotascope''), independently invented the gyroscope in the 1830's. Each of these devices employed a central object (sphere or disc) that could spin freely on a shaft. This was placed between three independent gimbals, which could also move freely. Bohnenberger's ``machine'' has much the same appearance as an armillary sphere. Such devices had been produced for at least the preceding three centuries. They were used to display the movements of various celestial bodies. However, armillary spheres are only simulations of celestial appearances, not actual demonstrations of physical phenomena. Gimbal systems similar to those found in gyroscopes were used on ships to level oil lamps from at least the sixteenth century and the ideas behind armillary spheres date back at least a millennium before that. So why was the gyroscope invented so late? Some possible reasons will be presented for the long delay between the development of the individual underlying components and the eventual appearance of the gyroscope in its modern form.
Instabilities of a gyroscope produced by rapidly rotating, highly viscous liquids
Damico, W. P., Jr.
1983-06-01
A series of experiments were conducted to determine the yaw behavior of a gyroscope that contained a liquid-filled rotor. Spin rates, liquid viscosities, and cylinder geometries were selected to produce a wide range of Reynolds numbers (5 aspect ratios (height/diameter) were tested: 1/1, 3/2, and 3/1. Coning frequencies for the free gyroscope were selected to be typical of spin-stabilized projectiles. Two distinct types of yaw behavior were observed with Reynolds number being the major controlling parameter. For RE > 1,000, the motion of the gyroscope was reasonably well predicted by classical liquid-filled shell theories that postulate a resonance between a natural frequency of the spinning liquid and the yaw frequency of the gyroscope. For these conditions the maximum yaw growth rate will occur when an eigenfrequency of the liquid is approximately equal to the gyroscope yaw frequency. For cases where RE< 1,000, the behavior of the gyroscope was not characterized by a resonant mechanism. Instead, the liquid-induced yaw moments and yaw growth rates grew monotonically with increasing yaw frequencies.
Uncertainty Relations and Possible Experience
Gregg Jaeger
2016-06-01
Full Text Available The uncertainty principle can be understood as a condition of joint indeterminacy of classes of properties in quantum theory. The mathematical expressions most closely associated with this principle have been the uncertainty relations, various inequalities exemplified by the well known expression regarding position and momentum introduced by Heisenberg. Here, recent work involving a new sort of “logical” indeterminacy principle and associated relations introduced by Pitowsky, expressable directly in terms of probabilities of outcomes of measurements of sharp quantum observables, is reviewed and its quantum nature is discussed. These novel relations are derivable from Boolean “conditions of possible experience” of the quantum realm and have been considered both as fundamentally logical and as fundamentally geometrical. This work focuses on the relationship of indeterminacy to the propositions regarding the values of discrete, sharp observables of quantum systems. Here, reasons for favoring each of these two positions are considered. Finally, with an eye toward future research related to indeterminacy relations, further novel approaches grounded in category theory and intended to capture and reconceptualize the complementarity characteristics of quantum propositions are discussed in relation to the former.
Carbon Nanotube Tape Vibrating Gyroscope
Tucker, Dennis Stephen (Inventor)
2016-01-01
A vibrating gyroscope includes a piezoelectric strip having length and width dimensions. The piezoelectric strip includes a piezoelectric material and carbon nanotubes (CNTs) substantially aligned and polled along the strip's length dimension. A spindle having an axis of rotation is coupled to the piezoelectric strip. The axis of rotation is parallel to the strip's width dimension. A first capacitance sensor is mechanically coupled to the spindle for rotation therewith. The first capacitance sensor is positioned at one of the strip's opposing ends and is spaced apart from one of the strip's opposing faces. A second capacitance sensor is mechanically coupled to the spindle for rotation therewith. The second capacitance sensor is positioned at another of the strip's opposing ends and is spaced apart from another of the strip's opposing faces. A voltage source applies an AC voltage to the piezoelectric strip.
Fiber Ring Optical Gyroscope (FROG)
1979-01-01
The design, construction, and testing of a one meter diameter fiber ring optical gyro, using 1.57 kilometers of single mode fiber, are described. The various noise components: electronic, thermal, mechanical, and optical, were evaluated. Both dc and ac methods were used. An attempt was made to measure the Earth rotation rate; however, the results were questionable because of the optical and electronic noise present. It was concluded that fiber ring optical gyroscopes using all discrete components have many serious problems that can only be overcome by discarding the discrete approach and adapting an all integrated optic technique that has the laser source, modulator, detector, beamsplitters, and bias element on a single chip.
High resolution capacitance detection circuit for rotor micro-gyroscope
Ming-Yuan Ren
2014-03-01
Full Text Available Conventional methods for rotor position detection of micro-gyroscopes include common exciting electrodes (single frequency and common sensing electrodes (frequency multiplex, but they have encountered some problems. So we present a high resolution and low noise pick-off circuit for micro-gyroscopes which utilizes the time multiplex method. The detecting circuit adopts a continuous-time current sensing circuit for capacitance measurement, and its noise analysis of the charge amplifier is introduced. The equivalent output noise power spectral density of phase-sensitive demodulation is 120 nV/Hz1/2. Tests revealed that the whole circuitry has a relative capacitance resolution of 1 × 10−8.
MEMS Gyroscope with Interferometric Detection Project
National Aeronautics and Space Administration — This SBIR Phase I project will develop a MEMS gyroscope that uses an ultra high resolution sensing technique for measuring proof mass motion. The goal is to...
Miniaturized High Performance Optical Gyroscope Project
National Aeronautics and Space Administration — We propose a new approach for to the design and fabrication of miniaturized Interferometric Fiber Optical Gyroscope (FOG) that enables the production of smaller IRU...
MEMS Gyroscope with Interferometric Detection Project
National Aeronautics and Space Administration — The proposed innovation is a novel MEMS gyroscope that uses micro-interferometric detection to measure the motion of the proof mass. Using an interferometric...
Wireless tuning fork gyroscope for biomedical applications
Abraham, Jose K.; Varadan, Vijay K.; Whitchurch, Ashwin K.; Sarukesi, K.
2003-07-01
This paper presents the development of a Bluetooth enabled wireless tuning fork gyroscope for the biomedical applications, including gait phase detection system, human motion analysis and physical therapy. This gyroscope is capable of measuring rotation rates between -90 and 90 and it can read the rotation information using a computer. Currently, the information from a gyroscope can trigger automobile airbag deployment during rollover, improve the accuracy and reliability of GPS navigation systems and stabilize moving platforms such as automobiles, airplanes, robots, antennas, and industrial equipment. Adding wireless capability to the existing gyroscope could help to expand its applications in many areas particularly in biomedical applications, where a continuous patient monitoring is quite difficult. This wireless system provides information on several aspects of activities of patients for real-time monitoring in hospitals.
Parametrically disciplined operation of a vibratory gyroscope
Shcheglov, Kirill V. (Inventor); Hayworth, Ken J. (Inventor); Challoner, A. Dorian (Inventor); Peay, Chris S. (Inventor)
2008-01-01
Parametrically disciplined operation of a symmetric nearly degenerate mode vibratory gyroscope is disclosed. A parametrically-disciplined inertial wave gyroscope having a natural oscillation frequency in the neighborhood of a sub-harmonic of an external stable clock reference is produced by driving an electrostatic bias electrode at approximately twice this sub-harmonic frequency to achieve disciplined frequency and phase operation of the resonator. A nearly symmetric parametrically-disciplined inertial wave gyroscope that can oscillate in any transverse direction and has more than one bias electrostatic electrode that can be independently driven at twice its oscillation frequency at an amplitude and phase that disciplines its damping to zero in any vibration direction. In addition, operation of a parametrically-disciplined inertial wave gyroscope is taught in which the precession rate of the driven vibration pattern is digitally disciplined to a prescribed non-zero reference value.
Nonlinear oscillations in coriolis based gyroscopes
Dag Kristiansen
1999-01-01
Full Text Available In this paper we model and analyze nonlinear oscillations which are known to exist in some Coriolis based gyroscopes due to large amplitude excitation in the drive loop. A detailed derivation of a dynamic model for a cylinder gyroscope which includes geometric nonlinearities is given, and energy transfer between the system's modes are analyzed using perturbation theory and by proposing a simplified model. The model is also simulated, and the results are shown to give an accurate description of the experimental results. This work is done in order to gain a better understanding of the gyroscope's dynamics, and is intended to be a starting point for designing nonlinear observers and vibration controllers for the gyroscope in order to increase the performance.
System Identification of MEMS Vibratory Gyroscope Sensor
Juntao Fei; Yuzheng Yang
2011-01-01
Fabrication defects and perturbations affect the behavior of a vibratory MEMS gyroscope sensor, which makes it difficult to measure the rotation angular rate. This paper presents a novel adaptive approach that can identify, in an online fashion, angular rate and other system parameters. The proposed approach develops an online identifier scheme, by rewriting the dynamic model of MEMS gyroscope sensor, that can update the estimator of angular rate adaptively and converge to its true value asy...
Estimates of errors of a gyroscope stabilized platform
Zbrutskiy, A. V.; Balabanov, I. V.
1984-08-01
A gyrostabilized platform has a four-frame cardan suspension in which one of the dynamically adjusted gyroscopes placed on the stabilized platform measures the angle of its deviation in the plane of the platform, while the second such gyroscope measures the deviation relative to this plane. The redundant first gyro can be used to correct the system and may also be a closed system itself. This paper studies the errors in the gyro stabilized platform due to the nonperpendicularity of the axes of the cardan suspension of the platform due to the nonperpendicularity of the axes of the cardan suspension of the platform as well as the disbalance of the components and dynamically adjustable gyroscopes. The cumbersome equations of motion for the system are written, neglecting dry frictional forces in the shafts of platform suspension, second order nonlinearities relative to the angular coordinates and their derivatives as well as terms with periodic coefficients which can affect the dynamics of the platform only in narrow ranges of frequency variations at parametric resonances.
Xukai Ding
2015-01-01
Full Text Available This paper presents a study of the frequency response and the scale-factor of a tuning fork micro-gyroscope operating at atmospheric pressure in the presence of an interference sense mode by utilizing the approximate transfer function. The optimal demodulation phase (ODP, which is always ignored in vacuum packaged micro-gyroscopes but quite important in gyroscopes operating at atmospheric pressure, is obtained through the transfer function of the sense mode, including the primary mode and the interference mode. The approximate transfer function of the micro-gyroscope is deduced in consideration of the interference mode and the ODP. Then, the equation describing the scale-factor of the gyroscope is also obtained. The impacts of the interference mode and Q-factor on the frequency response and the scale-factor of the gyroscope are analyzed through numerical simulations. The relationship between the scale-factor and the demodulation phase is also illustrated and gives an effective way to find out the ODP in practice. The simulation results predicted by the transfer functions are in close agreement with the results of the experiments. The analyses and simulations can provide constructive guidance on bandwidth and sensitivity designs of the micro-gyroscopes operating at atmospheric pressure.
Ding, Xukai; Li, Hongsheng; Ni, Yunfang; Sang, Pengcheng
2015-01-01
This paper presents a study of the frequency response and the scale-factor of a tuning fork micro-gyroscope operating at atmospheric pressure in the presence of an interference sense mode by utilizing the approximate transfer function. The optimal demodulation phase (ODP), which is always ignored in vacuum packaged micro-gyroscopes but quite important in gyroscopes operating at atmospheric pressure, is obtained through the transfer function of the sense mode, including the primary mode and the interference mode. The approximate transfer function of the micro-gyroscope is deduced in consideration of the interference mode and the ODP. Then, the equation describing the scale-factor of the gyroscope is also obtained. The impacts of the interference mode and Q-factor on the frequency response and the scale-factor of the gyroscope are analyzed through numerical simulations. The relationship between the scale-factor and the demodulation phase is also illustrated and gives an effective way to find out the ODP in practice. The simulation results predicted by the transfer functions are in close agreement with the results of the experiments. The analyses and simulations can provide constructive guidance on bandwidth and sensitivity designs of the micro-gyroscopes operating at atmospheric pressure.
XIAO Wen; LIU De-Wen; LIU Yang; YI Xiao-Su; CONG Lin
2008-01-01
@@ In the space environment, the precision of fibre optic gyroscopes (FOGs) degrades because of space radiation.Photonic components of FOGs axe affected by radiation, especially the polaxization-maintaining (PM) fibre coil.In relation to the space radiation environment characteristic, we have carried out a series of radiation experiments on a PM fibre coil with 60Co radiation source at different dose rates. Based on the experimental results, the formula between the PM-fibre loss and radiation dose rata is built, and the relation between the precision of FOG and radiation dose is obtained accordingly. The results strongly show that the precision of our FOG degrades owing to the attenuation of the polarization-maintaining fibre, which provides theoretical foundation for the radiation-resistant design of the FOG.
Dispersion-Enhanced Laser Gyroscope
Smith, David D.; Chang, Hongrok; Arissian, L.; Diels, J. C.
2008-01-01
We analyze the effect of a highly dispersive element placed inside a modulated optical cavity on the frequency and amplitude of the output modulation to determine the conditions for enhanced gyroscopic sensitivities. The element is treated as both a phase and amplitude filter, and the time-dependence of the cavity field is considered. Both atomic gases (two-level and multi-level) and optical resonators (single and coupled) are considered and compared as dispersive elements. We find that it is possible to simultaneously enhance the gyro scale factor sensitivity and suppress the dead band by using an element with anomalous dispersion that has greater loss at the carrier frequency than at the side-band frequencies, i.e., an element that simultaneously pushes and intensifies the perturbed cavity modes, e.g. a two-level absorber or an under-coupled optical resonator. The sensitivity enhancement is inversely proportional to the effective group index, becoming infinite at a group index of zero. However, the number of round trips required to reach a steady-state also becomes infinite when the group index is zero (or two). For even larger dispersions a steady-state cannot be achieved, and nonlinear dynamic effects such as bistability and periodic oscillations are predicted in the gyro response.
Dispersion-enhanced laser gyroscope
Smith, David D.; Chang, Hongrok; Arissian, L.; Diels, J. C.
2008-11-01
We analyze the effect of a highly dispersive element placed inside a modulated optical cavity on the frequency and amplitude of the output modulation to determine the conditions for enhanced gyroscopic sensitivities. The element is treated as both a phase and amplitude filter, and the time dependence of the cavity field is considered. Both atomic gases (two level and multilevel) and optical resonators (single and coupled) are considered and compared as dispersive elements. We find that it is possible to simultaneously enhance the gyro scale factor sensitivity and suppress the dead band by using an element with anomalous dispersion that has greater loss at the carrier frequency than at the sideband frequencies, i.e., an element that simultaneously pushes and intensifies the perturbed cavity modes, e.g. a two-level absorber or an undercoupled optical resonator. The sensitivity enhancement is inversely proportional to the effective group index, becoming infinite at a group index of zero. However, the number of round trips required to reach a steady state also becomes infinite when the group index is zero (or two). For even larger dispersions a steady state cannot be achieved, and nonlinear dynamic effects such as bistability and periodic oscillations are predicted in the gyro response.
Gas Damping Coefficient Research for MEMS Comb Linear Vibration Gyroscope
Qiufen, G; Feng, S; Fuqiang, L
2008-01-01
Silicon-MEMS gyroscope is an important part of MEMS (Micro Electrical Mechanical System). There are some disturb ignored in traditional gyroscope that must be evaluated newly because of its smaller size (reach the level of micron). In these disturb, the air pressure largely influences the performance of MEMS gyroscope. Different air pressure causes different gas damping coefficient for the MEMS comb linear vibration gyroscope and different gas damping coefficient influences the quality factor of the gyroscope directive. The quality factor influences the dynamic working bandwidth of the MEMS comb linear vibration gyroscope, so it is influences the output characteristic of the MEMS comb linear vibration gyroscope. The paper shows the relationship between the air pressure and the output amplified and phase of the detecting axis through analyzing the air pressure influence on the MEMS comb linear vibration gyroscope. It discusses the influence on the frequency distribute and quality factor of the MEMS comb linear...
Bandwidth optimization design of a multi degree of freedom MEMS gyroscope.
Si, Chaowei; Han, Guowei; Ning, Jin; Yang, Fuhua
2013-08-14
A new robust multi-degree of freedom (multi-DOF) MEMS gyroscope is presented in this paper. The designed gyroscope has its bandwidth and amplification factor of the sense mode adjusted more easily than the previous reported multi-DOF MEMS gyroscopes. Besides, a novel spring system with very small coupling stiffness is proposed, which helps achieve a narrow bandwidth and a high amplification factor for a 2-DOF vibration system. A multi-DOF gyroscope with the proposed weak spring system is designed, and simulations indicate that when the operating frequency is set at 12.59 kHz, the flat frequency response region of the sense mode can be designed as narrow as 80 Hz, and the amplification factor of the sense mode at the operating frequency is up to 91, which not only protects the amplification factor from instability against process and temperature variations, but also sacrifices less performance. An experiment is also carried out to demonstrate the validity of the design. The multi-DOF gyroscope with the proposed weak coupling spring system is capable of achieving a good tradeoff between robustness and the performance.
Bandwidth Optimization Design of a Multi Degree of Freedom MEMS Gyroscope
Fuhua Yang
2013-08-01
Full Text Available A new robust multi-degree of freedom (multi-DOF MEMS gyroscope is presented in this paper. The designed gyroscope has its bandwidth and amplification factor of the sense mode adjusted more easily than the previous reported multi-DOF MEMS gyroscopes. Besides, a novel spring system with very small coupling stiffness is proposed, which helps achieve a narrow bandwidth and a high amplification factor for a 2-DOF vibration system. A multi-DOF gyroscope with the proposed weak spring system is designed, and simulations indicate that when the operating frequency is set at 12.59 kHz, the flat frequency response region of the sense mode can be designed as narrow as 80 Hz, and the amplification factor of the sense mode at the operating frequency is up to 91, which not only protects the amplification factor from instability against process and temperature variations, but also sacrifices less performance. An experiment is also carried out to demonstrate the validity of the design. The multi-DOF gyroscope with the proposed weak coupling spring system is capable of achieving a good tradeoff between robustness and the performance.
A systematic approach for precision electrostatic mode tuning of a MEMS gyroscope
Hu, Z. X.; Gallacher, B. J.; Burdess, J. S.; Bowles, S. R.; Grigg, H. T. D.
2014-12-01
In this paper a systematic approach to precision electrostatic frequency tuning of the operational modes of a MEMS ring vibratory gyroscope is presented. In both rate and rate integrating gyroscopes the frequency split between the two modes of vibration which detect the Coriolis acceleration is one of the principal factors in determining the sensitivity and noise floor of the sensor. In high precision applications in the defence/aerospace sector a frequency split of the order of 10 mHz or less is highly desirable. In the ground-breaking Hemispherical Resonator Gyroscope (HRG) electrostatic tuning has been employed as a tuning mechanism. However, a description of the procedure is not available in the literature. The tuning scheme described here involves assessing mode mistuning by the ratio of the in-phase and quadrature components of the response to an external force that has similar properties to the gyroscopic force resulting from Coriolis action, and choosing the tuning voltages so that independent modification of the elements of the system stiffness matrix can be achieved. Experiments on a commercially available gyroscope with a natural frequency of 14 kHz show that the frequency split can be reduced from 1.5 Hz to 6 mHz. This represents a frequency precision of better than 1 part in a million.
A Digitalized Gyroscope System Based on a Modified Adaptive Control Method
Dunzhu Xia
2016-03-01
Full Text Available In this work we investigate the possibility of applying the adaptive control algorithm to Micro-Electro-Mechanical System (MEMS gyroscopes. Through comparing the gyroscope working conditions with the reference model, the adaptive control method can provide online estimation of the key parameters and the proper control strategy for the system. The digital second-order oscillators in the reference model are substituted for two phase locked loops (PLLs to achieve a more steady amplitude and frequency control. The adaptive law is modified to satisfy the condition of unequal coupling stiffness and coupling damping coefficient. The rotation mode of the gyroscope system is considered in our work and a rotation elimination section is added to the digitalized system. Before implementing the algorithm in the hardware platform, different simulations are conducted to ensure the algorithm can meet the requirement of the angular rate sensor, and some of the key adaptive law coefficients are optimized. The coupling components are detected and suppressed respectively and Lyapunov criterion is applied to prove the stability of the system. The modified adaptive control algorithm is verified in a set of digitalized gyroscope system, the control system is realized in digital domain, with the application of Field Programmable Gate Array (FPGA. Key structure parameters are measured and compared with the estimation results, which validated that the algorithm is feasible in the setup. Extra gyroscopes are used in repeated experiments to prove the commonality of the algorithm.
A Digitalized Gyroscope System Based on a Modified Adaptive Control Method.
Xia, Dunzhu; Hu, Yiwei; Ni, Peizhen
2016-01-01
In this work we investigate the possibility of applying the adaptive control algorithm to Micro-Electro-Mechanical System (MEMS) gyroscopes. Through comparing the gyroscope working conditions with the reference model, the adaptive control method can provide online estimation of the key parameters and the proper control strategy for the system. The digital second-order oscillators in the reference model are substituted for two phase locked loops (PLLs) to achieve a more steady amplitude and frequency control. The adaptive law is modified to satisfy the condition of unequal coupling stiffness and coupling damping coefficient. The rotation mode of the gyroscope system is considered in our work and a rotation elimination section is added to the digitalized system. Before implementing the algorithm in the hardware platform, different simulations are conducted to ensure the algorithm can meet the requirement of the angular rate sensor, and some of the key adaptive law coefficients are optimized. The coupling components are detected and suppressed respectively and Lyapunov criterion is applied to prove the stability of the system. The modified adaptive control algorithm is verified in a set of digitalized gyroscope system, the control system is realized in digital domain, with the application of Field Programmable Gate Array (FPGA). Key structure parameters are measured and compared with the estimation results, which validated that the algorithm is feasible in the setup. Extra gyroscopes are used in repeated experiments to prove the commonality of the algorithm.
Direct comparison of nuclear-spin-gyroscope schemes
Dong, Haifeng; Gao, Yang
2016-01-01
We demonstrate that NMR gyroscope and comagnetometer SERF gyroscope can be described with a common model, which explains the compensation and enhancement effects in the same way. The error models and the advantage/disadvantage of two kinds of atomic spin gyroscope are also discussed.
Dynamics of micromachined vibrating gimbal and wheel gyroscope
TijingCAI
2000-01-01
We deduce dynamic equations of micromachined vibrating gimbal and wheel gyroscope and give an approximate solution of enough accuracy. The comparison between the approximate solution and the solution used often in the literature is given. According to property of the approximate solution a decoupled two-axes gyroscope will be composed of two single-axes gyroscopes.
Analysis of compensation for a g-sensitivity scale-factor error for a MEMS vibratory gyroscope
Park, Byung Su; Han, KyungJun; Lee, SangWoo; Yu, MyeongJong
2015-11-01
In this paper, we present recent work on the g-sensitivity error of the MEMS vibratory gyroscope. Generally, the g-sensitivity error has been ignored in the use of commercial MEMS vibratory gyroscopes, but it deserves our attention if we are to achieve tactical grade performance for military applications. First, we mathematically show the reason the g-sensitivity error occurs as an additional scale-factor error during the use of MEMS vibratory gyroscopes. Then, we estimate the g-sensitivity error using FEM simulation and verify it by experiment using a centrifugal machine. Consequently, we propose a compensation model to accommodate the g-sensitivity error of a gyroscope and confirm the theoretical prediction with experimental results.
Passive, free-space laser gyroscope
Korth, W Zach; Hall, Evan D; Arai, Koji; Gustafson, Eric K; Adhikari, Rana X
2015-01-01
Laser gyroscopes making use of the Sagnac effect have been used as highly accurate rotation sensors for many years. First used in aerospace and defense applications, these devices have more recently been used for precision seismology and in other research settings. In particular, mid-sized (~1 m-scale) laser gyros have been under development as tilt sensors to augment the adaptive active seismic isolation systems in terrestrial interferometric gravitational wave detectors. The most prevalent design is the "active" gyroscope, in which the optical ring cavity used to measure the Sagnac degeneracy breaking is itself a laser resonator. In this article, we describe another topology: a "passive" gyroscope, in which the sensing cavity is not itself a laser but is instead tracked using external laser beams. While subject to its own limitations, this design is free from the deleterious lock-in effects observed in active systems, and has the advantage that it can be constructed using commercially available components. ...
Non-gyroscope DR and adaptive information fusion algorithm used in GPS/DR device
Li Qingli; Xue Yongqi; Shang Yanlei; Shi Pengfei
2006-01-01
In view of the problems existing in GPS, a non-gyroscope DR is introduced. The operating principle and the algorithm of the GPS/DR device are also presented. By operating measured data synthetically, linear observation equations are obtained for the information fusion algorithm. This approach avoids model error due to linearizing nonlinear observation equations in the conventional algorithm, so that the stability of information fusion algorithm is improved and computation expenses are reduced. Field running experiments show that satisfactory accuracy can be obtained by the proposed navigation model and algorithm for the non-gyroscope GPS/DR device.
Yibo Feng
2015-05-01
Full Text Available We present an adaptive algorithm for a system integrated with micro-electro-mechanical systems (MEMS gyroscopes and a compass to eliminate the influence from the environment, compensate the temperature drift precisely, and improve the accuracy of the MEMS gyroscope. We use a simplified drift model and changing but appropriate model parameters to implement this algorithm. The model of MEMS gyroscope temperature drift is constructed mostly on the basis of the temperature sensitivity of the gyroscope. As the state variables of a strong tracking Kalman filter (STKF, the parameters of the temperature drift model can be calculated to adapt to the environment under the support of the compass. These parameters change intelligently with the environment to maintain the precision of the MEMS gyroscope in the changing temperature. The heading error is less than 0.6° in the static temperature experiment, and also is kept in the range from 5° to −2° in the dynamic outdoor experiment. This demonstrates that the proposed algorithm exhibits strong adaptability to a changing temperature, and performs significantly better than KF and MLR to compensate the temperature drift of a gyroscope and eliminate the influence of temperature variation.
Feng, Yibo; Li, Xisheng; Zhang, Xiaojuan
2015-05-13
We present an adaptive algorithm for a system integrated with micro-electro-mechanical systems (MEMS) gyroscopes and a compass to eliminate the influence from the environment, compensate the temperature drift precisely, and improve the accuracy of the MEMS gyroscope. We use a simplified drift model and changing but appropriate model parameters to implement this algorithm. The model of MEMS gyroscope temperature drift is constructed mostly on the basis of the temperature sensitivity of the gyroscope. As the state variables of a strong tracking Kalman filter (STKF), the parameters of the temperature drift model can be calculated to adapt to the environment under the support of the compass. These parameters change intelligently with the environment to maintain the precision of the MEMS gyroscope in the changing temperature. The heading error is less than 0.6° in the static temperature experiment, and also is kept in the range from 5° to -2° in the dynamic outdoor experiment. This demonstrates that the proposed algorithm exhibits strong adaptability to a changing temperature, and performs significantly better than KF and MLR to compensate the temperature drift of a gyroscope and eliminate the influence of temperature variation.
System Identification of MEMS Vibratory Gyroscope Sensor
Juntao Fei
2011-01-01
Full Text Available Fabrication defects and perturbations affect the behavior of a vibratory MEMS gyroscope sensor, which makes it difficult to measure the rotation angular rate. This paper presents a novel adaptive approach that can identify, in an online fashion, angular rate and other system parameters. The proposed approach develops an online identifier scheme, by rewriting the dynamic model of MEMS gyroscope sensor, that can update the estimator of angular rate adaptively and converge to its true value asymptotically. The feasibility of the proposed approach is analyzed and proved by Lyapunov's direct method. Simulation results show the validity and effectiveness of the online identifier.
Problem of the gyroscopic stabilizer damping
Šklíba J.
2009-06-01
Full Text Available The gyroscopic stabilization of the vibro-isolation system of an ambulance couch is analyzed. This paper follows several previous papers, which concern the derivation of the complete system of appropriate differential equations and some analyses were provided there, as well. It was supposed that mass matrix, stiffness matrix and gyroscope impulse-moment remain constant and the stability of equilibrium state was solved according to different alternatives of the damping and of the radial correction. Little known theorems of the stability were used there. With respect to these theorems, vibro-isolation systems can be classified according to odd or even number of generalized coordinates.
The Confrontation between General Relativity and Experiment
Will Clifford
2001-01-01
Full Text Available The status of experimental tests of general relativity and of theoretical frameworks for analysing them are reviewed. Einstein's equivalence principle (EEP is well supported by experiments such as the Eötvös experiment, tests of special relativity, and the gravitational redshift experiment. Future tests of EEP and of the inverse square law will search for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, and the Nordtvedt effect in lunar motion. Gravitational wave damping has been detected in an amount that agrees with general relativity to half a percent using the Hulse-Taylor binary pulsar, and new binary pulsar systems may yield further improvements.When direct observation of gravitational radiation from astrophysical sources begins, new tests of general relativity will be possible.
Research of thermal characteristic and compensation algorithm for MEMS-gyroscope%微机械陀螺温度特性及其补偿算法研究
温祖强; 钱峰
2011-01-01
微机械陀螺是近年发展起来的一种角速率传感器,具有体积小、重量轻、价格便宜等优点.但是微机械陀螺的精度很容易受到温度的影响.本文介绍了微机械陀螺的温度特性,并且通过实验推导出陀螺输出与温度的关系,在此基础上使用了最小二乘拟合与神经网络两种算法进行温度补偿并将结果进行了对比.通过实验验证对于由温度导致的误差有很好的补偿效果,为今后在实际中的应用提供了一种参考途径.%MEMS-gyroscope is a kind of angular-rate-sensor developed in recent years, which has smaller size, lighter weight and lower cost than traditional rate-sensor. But temperature changing largely influences the performance of MEMS-gyroscope. The influence by temperature changing is analyzed. Relation among zero-rate-output, phase of driveaxis and temperature is derived. Therefore, two compensation algorithms which are least square method and neural network method are introduced. The thermal bias drift of the gyroscope compensated by temperature-experiment is reduced. The result gives a reference of the future use of MEMS-gyroscope.
The Confrontation between General Relativity and Experiment
Will, Clifford M
2014-01-01
The status of experimental tests of general relativity and of theoretical frameworks for analyzing them are reviewed and updated. Einstein's equivalence principle (EEP) is well supported by experiments such as the Eotvos experiment, tests of local Lorentz invariance and clock experiments. Ongoing tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, the Nordtvedt effect in lunar motion, and frame-dragging. Gravitational-wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse-Taylor binary pulsar, and a growing family of other binary pulsar systems is yielding new tests, especially of strong-field effects. Current and future tests of relativity will center on strong gravity and gravitational waves.
The Confrontation between General Relativity and Experiment.
Will, Clifford M
2014-01-01
The status of experimental tests of general relativity and of theoretical frameworks for analyzing them is reviewed and updated. Einstein's equivalence principle (EEP) is well supported by experiments such as the Eötvös experiment, tests of local Lorentz invariance and clock experiments. Ongoing tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, the Nordtvedt effect in lunar motion, and frame-dragging. Gravitational wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse-Taylor binary pulsar, and a growing family of other binary pulsar systems is yielding new tests, especially of strong-field effects. Current and future tests of relativity will center on strong gravity and gravitational waves.
Smooth Archimedean-spiral ring waveguide for cold atomic gyroscope
Xiaojun Jiang; Xiaolin Li; Haichao Zhang; Yuzhu Wang
2016-01-01
We propose a robust scheme that creates a toroidal magnetic potential on a single-layer atom chip.The wire layout consists of two interleaved Archimedean spirals,which avoids the trapping perturbation caused by the input and output ports.By using a rotation bias field,the minimum of the time-averaged orbiting potential is lifted from zero,and then a relatively smooth and harmonic ring trap is formed.The location of the waveguide is immune to the magnetic variations,as it is only determined by the wire layout.The ring waveguide offers an ideal solution to developing a compact and portable atomic gyroscope.
High-performance micromachined gyroscope with a slanted suspension cantilever
Xiao Dingbang; Wu Xuezhong; Hou Zhanqiang; Chen Zhihua; Dong Peitao; Li Shengyi, E-mail: Dingbangxiao@yahoo.com.c [Microsystem Laboratory, National University of Defense Technology, Changsha 410073 (China)
2009-04-15
This paper presents a novel structure for improving the stability and the mechanical noise of micromachined gyroscopes. Only one slanted cantilever is used for suspension in this gyroscope, so the asymmetry spring and the thermal stress, which most micromachined gyroscopes suffer from, are reduced. In order to reduce the mechanical noise, the proof masses are designed to be much larger than in most micromachined gyroscopes. The gyroscope chip is sealed at 0.001 Pa vacuum. A gyroscope sample and its read-out circuit are fabricated. The scale factor of this gyroscope is measured as 57.6 mV/(deg/sec) with a nonlinearity better than 0.12% in a measurement range of +-100 deg/sec. The short-term bias stability in 20 min is 60 deg/h.
High-performance micromachined gyroscope with a slanted suspension cantilever
Xiao Dingbang; Wu Xuezhong; Hou Zhanqiang; Chen Zhihua; Dong Peitao; Li Shengyi
2009-01-01
This paper presents a novel structure for improving the stability and the mechanical noise of micromachined gyroscopes.Only one slanted cantilever is used for suspension in this gyroscope,so the asymmetry spring and the thermal stress,which most micromachined gyroscopes suffer from,are reduced.In order to reduce the mechanical noise,the proof masses are designed to be much larger than in most micromachined gyroscopes.The gyroscope chip is sealed at 0.00 1 Pa vacuum.A gyroscope sample and its read-out circuit are fabricated.The scale factor of this gyroscope is measured as 57.6 mV/(deg/sec) with a nonlinearity better than 0.12%in a measurement range of ±100 deg/sec.The short-term bias stability in 20 min is 60 deg/h.
Gyroscopic stabilization of non-conservative systems
Kirillov, Oleg N. [Dynamics Group, Department of Mechanical Engineering, Technical University of Darmstadt, Hochschulstr. 1, 64289 Darmstadt (Germany) and Institute of Mechanics, Moscow State Lomonosov University, Michurinskii pr. 1, 119192 Moscow (Russian Federation)]. E-mail: kirillov@dyn.tu-darmstadt.de
2006-11-20
Gyroscopic stabilization of a linear conservative system, which is statically unstable, can be either improved or destroyed by weak damping and circulatory forces. This is governed by Whitney umbrella singularity of the boundary of the asymptotic stability domain of the perturbed system.
Design and analysis of a micromachined gyroscope
Zarei, Nilgoon; Leung, Albert; Jones, John D.
2012-03-01
This paper describes the simulation and design of a MEMS thermal gyroscope and optimizing the design for increased sensitivity through the use of the Comsol Multiphysics software package. Two different designs are described, and the effects of working fluid properties are explored. A prototype of this device has been fabricated using techniques for rapid prototyping of MEMS transducers.
Bias Drift Estimation for MEMS Gyroscope Used in Inertial Navigation
Cechowicz Radosław
2017-06-01
Full Text Available MEMS gyroscopes can provide useful information for dead-reckoning navigation systems if suitable error compensation algorithm is applied. If there is information from other sources available, usually the Kalman filter is used for this task. This work focuses on improving the performance of the sensor if no other information is available and the integration error should be kept low during periods of still (no movement operation. A filtering algorithm is proposed to follow bias change during sensor operation to reduce integration error and extend time between successive sensor calibrations. The advantage of the proposed solution is its low computational complexity which allows implementing it directly in the micro-controller of controlling the MEMS gyroscope. An intelligent sensor can be build this way, suitable for use in control systems for mobile platforms. Presented results of a simple experiment show the improvement of the angle estimation. During the 12 hours experiment with a common MEMS sensor and no thermal compensation, the maximum orientation angle error was below 8 degrees.
The gyroscope testbed: A verification of the gravity probe B suspension system
Brumley, Robert Willard
The verification of precision control systems for use in space-based applications can be extremely challenging. Often, the presence of the 1-g field substantively changes the control problem, making it impossible to test directly on the Earth. This talk discusses a new approach to testing and verification of the gyroscope suspension system for the Gravity Probe B (GP-B) experimental test of General Relativity. The verification approach involves the creation of a new testbed that has the same input-output characteristics and dynamics as a GP-B gyroscope. This involves real physical hardware that moves like a real gyroscope, allowing the suspension system's performance to be measured directly without the need to break any internal connections or bypass internal subsystems. The user free to define any set of disturbances from a 1-g ground levitation to a 10-8 g science mission. The testbed has two main subsystems. The mechanical subsystem is comprised of six parallel plate capacitors whose spacing is controlled by precision actuators. These actuators are the physical interface to the suspension system and create the electrode-rotor capacitances present in a real gyroscope. The closed-loop positioning noise of the system is approximately 10 pm/√Hz, enabling the commanding of position variations a fraction the size of a single atom of Silicon. The control subsystem has a DSP-based high-speed nonlinear controller that forces the actuators to follow the dynamics of a gyroscope. The device has been shown to faithfully represent a gyroscope in 1-g levitation, and a robustness analysis has been performed to prove that it correctly tests the stability of the on-orbit system. The testbed is then used to measure directly suspension system performance in a variety of on-orbit scenarios. Gyroscope levitation in 10-8 g conditions is demonstrated. The robustness of gyroscope levitation to transient disturbances such as micrometeorite impacts on the space vehicle and transitions
Science Instrument Support Electronics Systems for the Relativity Mission Satellite, Gravity Probe B
Bencze, W. J.; Brumley, R. W.; Buchman, S.; Clarke, B.; Hipkins, D. N.; Farley, R.; Shestople, P.; Meriwether, D.; Gray, C.
The Relativity Mission, Gravity Probe B (GP-B), uses four redundant high precision electrostatically suspended mechanical gyroscopes for measuring the relativistic precessions of the frame of reference in a 640 km polar orbit. The two precessions to be measured are predicted in General Relativity are the geodetic effect, 6.6 arcsec/year, and the frame dragging effect, 0.042 arcsec/year. The Science Instrument Support Electronics or Payload Electronics Package enables this measurement to be performed by providing the necessary control and monitoring functions for the Science Instrument Assembly that contains the four gyroscopes and reference star tracking telescope. This paper describes the overall architecture of the Payload Electronics system and the design and operation of its component parts: 1) the SQUID Readout electronics (SRE) for gyroscope orientation measurement, 2) The Gyroscope Suspension System (GSS) for gyroscope electrostatic suspension and spin axis alignment, 3) the Telescope Readout Electronics (TRE) for measurement of the reference star location, 4) the Experiment Control Unit (ECU) for heater, valve, and rotor electrostatic charge control and thermometry, 5) the custom GPS receiver for orbital position determination and time reference generation, and 6) the Gas Management Assembly (GMA) that controls and routes the gaseous helium used for initial gyroscope spin-up. Contingent upon a successful launch of Gravity Probe on April 17 2004, preliminary performance results will be presented along side the predicated performance estimates derived from system analysis and test on the ground prior to launch.
The signal detection for the levitated rotor micro gyroscope
Huang Xiaogang; Chen Wenyuan; Liu Wu; Zhang Weiping; Wu Xiaosheng [National Key Laboratory of Nano/Micro Fabrication Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai, 200030 (China)
2006-04-01
In the novel prototype of micro gyroscope structure, the new configured capacitance sensing scheme for the micro gyroscope is analyzed and the virtual instrument based detection scheme is implemented. The digital lock-in amplifier is employed in the capacitance detection to restrain the noise interference. The capacitance analysis shows that 1000aF capacitance variation corresponds to 0.1 degree of the turn angle. The differential capacitance bridge and the charge integral amplifier are used as the front signal input interface. In the implementation of digital lock-in amplifier, a new routine which warranted the exactly matching of the reference phase to signal phase was proposed. The result of the experiment shows that digital lock-in amplifier can greatly eliminate the noise in the output signal. The linearity of the turn angle output is 2.3% and the minimum resolution of turn angle is 0.04 degree. The application of the digital lock-in amplifier in the field of micro-electro-mechanical-system (MEMS) device signal detection is a new attempt, and it shows the prospective for a high-performance application.
Optimal Design of a Center Support Quadruple Mass Gyroscope (CSQMG
Tian Zhang
2016-04-01
Full Text Available This paper reports a more complete description of the design process of the Center Support Quadruple Mass Gyroscope (CSQMG, a gyro expected to provide breakthrough performance for flat structures. The operation of the CSQMG is based on four lumped masses in a circumferential symmetric distribution, oscillating in anti-phase motion, and providing differential signal extraction. With its 4-fold symmetrical axes pattern, the CSQMG achieves a similar operation mode to Hemispherical Resonant Gyroscopes (HRGs. Compared to the conventional flat design, four Y-shaped coupling beams are used in this new pattern in order to adjust mode distribution and enhance the synchronization mechanism of operation modes. For the purpose of obtaining the optimal design of the CSQMG, a kind of applicative optimization flow is developed with a comprehensive derivation of the operation mode coordination, the pseudo mode inhibition, and the lumped mass twisting motion elimination. The experimental characterization of the CSQMG was performed at room temperature, and the center operation frequency is 6.8 kHz after tuning. Experiments show an Allan variance stability 0.12°/h (@100 s and a white noise level about 0.72°/h/√Hz, which means that the CSQMG possesses great potential to achieve navigation grade performance.
Optimal Design of a Center Support Quadruple Mass Gyroscope (CSQMG).
Zhang, Tian; Zhou, Bin; Yin, Peng; Chen, Zhiyong; Zhang, Rong
2016-01-01
This paper reports a more complete description of the design process of the Center Support Quadruple Mass Gyroscope (CSQMG), a gyro expected to provide breakthrough performance for flat structures. The operation of the CSQMG is based on four lumped masses in a circumferential symmetric distribution, oscillating in anti-phase motion, and providing differential signal extraction. With its 4-fold symmetrical axes pattern, the CSQMG achieves a similar operation mode to Hemispherical Resonant Gyroscopes (HRGs). Compared to the conventional flat design, four Y-shaped coupling beams are used in this new pattern in order to adjust mode distribution and enhance the synchronization mechanism of operation modes. For the purpose of obtaining the optimal design of the CSQMG, a kind of applicative optimization flow is developed with a comprehensive derivation of the operation mode coordination, the pseudo mode inhibition, and the lumped mass twisting motion elimination. The experimental characterization of the CSQMG was performed at room temperature, and the center operation frequency is 6.8 kHz after tuning. Experiments show an Allan variance stability 0.12°/h (@100 s) and a white noise level about 0.72°/h/√Hz, which means that the CSQMG possesses great potential to achieve navigation grade performance.
The Confrontation between General Relativity and Experiment
Will Clifford M.
2006-03-01
Full Text Available The status of experimental tests of general relativity and of theoretical frameworks for analyzing them is reviewed. Einstein’s equivalence principle (EEP is well supported by experiments such as the Eötvös experiment, tests of special relativity, and the gravitational redshift experiment. Ongoing tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, and the Nordtvedt effect in lunar motion. Gravitational wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse-Taylor binary pulsar, and other binary pulsar systems have yielded other tests, especially of strong-field effects. When direct observation of gravitational radiation from astrophysical sources begins, new tests of general relativity will be possible.
陀螺技术分类与动作结构分析%An analysis on the technology classification and movement structure of gyroscope
宋卫
2014-01-01
结合十多年从事民族传统体育陀螺项目教学、训练及竞赛的实践经验，对民族传统体育陀螺项目的技术进行了分类，就陀螺技术的特点、技术动作结构等进行了分析。%Combine the teaching,training and competition experience of gyroscope in recent ten years,this article classification the technology of gyroscope,and analyzes the technology characteristics,technology movement structure of gyroscope.
The Confrontation between General Relativity and Experiment
Clifford M. Will
2014-06-01
Full Text Available The status of experimental tests of general relativity and of theoretical frameworks for analyzing them is reviewed and updated. Einstein’s equivalence principle (EEP is well supported by experiments such as the Eötvös experiment, tests of local Lorentz invariance and clock experiments. Ongoing tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, the Nordtvedt effect in lunar motion, and frame-dragging. Gravitational wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse–Taylor binary pulsar, and a growing family of other binary pulsar systems is yielding new tests, especially of strong-field effects. Current and future tests of relativity will center on strong gravity and gravitational waves.
EIGENVALUE PROBLEM OF A LARGE SCALE INDEFINITE GYROSCOPIC DYNAMIC SYSTEM
SUI Yong-feng; ZHONG Wan-xie
2006-01-01
Gyroscopic dynamic system can be introduced to Hamiltonian system. Based on an adjoint symplectic subspace iteration method of Hamiltonian gyroscopic system,an adjoint symplectic subspace iteration method of indefinite Hamiltonian function gyroscopic system was proposed to solve the eigenvalue problem of indefinite Hamiltonian function gyroscopic system. The character that the eigenvalues of Hamiltonian gyroscopic system are only pure imaginary or zero was used. The eigenvalues that Hamiltonian function is negative can be separated so that the eigenvalue problem of positive definite Hamiltonian function system was presented, and an adjoint symplectic subspace iteration method of positive definite Hamiltonian function system was used to solve the separated eigenvalue problem. Therefore, the eigenvalue problem of indefinite Hamiltonian function gyroscopic system was solved, and two numerical examples were given to demonstrate that the eigensolutions converge exactly.
Passive ring resonator micro-optical gyroscopes
Venediktov, V. Yu; Filatov, Yu V.; Shalymov, E. V.
2016-05-01
This paper reviews recent advances in passive micro-optical gyroscopes. In the last decade, most research effort in the area of micro-optical gyros has been concentrated on a configuration that takes advantage of a single-mode passive ring resonator, which is usually fabricated using integrated optical technologies. The dimensions of such micro-optical gyros are comparable to those of micromechanical gyroscopes (area of 10 to 100 mm2) and their sensitivity is considerably better than the sensitivity of the latter, approaching that of fibre-optic and laser gyros. Moreover, microoptical gyros can be made as a single integrated circuit, like the micromechanical gyros, but they have no movable parts, in contrast to their micromechanical counterparts. We also describe the development and investigation of micro-optical gyros produced in our studies.
Optimization of the geometrical stability in square ring laser gyroscopes
Santagata, R; Belfi, J; Beverini, N; Cuccato, D; Di Virgilio, A; Ortolan, A; Porzio, A; Solimeno, S
2014-01-01
Ultra sensitive ring laser gyroscopes are regarded as potential detectors of the general relativistic frame-dragging effect due to the rotation of the Earth: the project name is GINGER (Gyroscopes IN GEneral Relativity), a ground-based triaxial array of ring lasers aiming at measuring the Earth rotation rate with an accuracy of 10^-14 rad/s. Such ambitious goal is now within reach as large area ring lasers are very close to the necessary sensitivity and stability. However, demanding constraints on the geometrical stability of the laser optical path inside the ring cavity are required. Thus we have started a detailed study of the geometry of an optical cavity, in order to find a control strategy for its geometry which could meet the specifications of the GINGER project. As the cavity perimeter has a stationary point for the square configuration, we identify a set of transformations on the mirror positions which allows us to adjust the laser beam steering to the shape of a square. We show that the geometrical s...
Klein-Gordon and Dirac gyroscopes
SadurnI, E [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos (Mexico)], E-mail: sadurni@fis.unam.mx
2009-01-09
The formulation of a rigid body in relativistic quantum mechanics is studied. Departing from an alternate approach at the relativistic classical level, the corresponding Klein-Gordon and Dirac operators for the rigid body are obtained in covariant form. The resulting wave equations are shown to be consistent, by construction, with earlier definitions of a relativistic rigid body by Aldinger et al (1983 Phys. Rev. D 28 3020). Wavefunctions and spectra for both cases are obtained explicitly, including the Dirac gyroscope with asymmetries.
Gas Damping Coefficient Research for MEMS Comb Linear Vibration Gyroscope
Qiufen, G.; Yuansheng, G.; Feng, S.; Fuqiang, L.
2007-01-01
Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing); International audience; Silicon-MEMS gyroscope is an important part of MEMS ( Micro Electrical Mechanical System). There are some disturb ignored in traditional gyroscope that must be evaluated newly because of its smaller size (reach the level of micron). In these disturb, the air pressure largely influences the performance of MEMS gyroscope. Different air pressure causes different gas damping coeffic...
Evolutionary Computation Applied to the Tuning of MEMS Gyroscopes
Keymeulen, Didier; Fink, Wolfgang; Ferguson, Michael I.; Peay, Chris; Oks, Boris; Terrile, Richard; Yee, Karl
2005-01-01
We propose a tuning method for MEMS gyroscopes based on evolutionary computation to efficiently increase the sensitivity of MEMS gyroscopes through tuning and, furthermore, to find the optimally tuned configuration for this state of increased sensitivity. The tuning method was tested for the second generation JPL/Boeing Post-resonator MEMS gyroscope using the measurement of the frequency response of the MEMS device in open-loop operation.
System Dynamics and Adaptive Control for MEMS Gyroscope Sensor
Juntao Fei; Hongfei Ding
2010-01-01
This paper presents an adaptive control approach for Micro-Electro-Mechanical Systems (MEMS) z-axis gyroscope sensor. The dynamical model of MEMS gyroscope sensor is derived and adaptive state tracking control for MEMS gyroscope is developed. The proposed adaptive control approaches can estimate the angular velocity and the damping and stiffness coefficients including the coupling terms due to the fabrication imperfection. The stability of the closed-loop systems is established with the propo...
A Large Area Fiber Optic Gyroscope on multiplexed fiber network
Clivati, Cecilia; Calonico, Davide; Costanzo, Giovanni A.; Mura, Alberto; Pizzocaro, Marco; Levi, Filippo
2012-01-01
We describe a fiber optical gyroscope based on the Sagnac effect realized on a multiplexed telecom fiber network. Our loop encloses an area of 20 km^2 and coexists with Internet data traffic. This Sagnac interferometer achieves a sensitivity of about 1e-8 (rad/s)/sqrt(Hz), thus approaching ring laser gyroscopes without using narrow-linewidth laser nor sophisticated optics. The proposed gyroscope is sensitive enough for seismic applications, opening new possibilities for this kind of optical f...
A Large Area Fiber Optic Gyroscope on multiplexed fiber network
Clivati, Cecilia; Costanzo, Giovanni A; Mura, Alberto; Pizzocaro, Marco; Levi, Filippo
2012-01-01
We describe a fiber optical gyroscope based on the Sagnac effect realized on a multiplexed telecom fiber network. Our loop encloses an area of 20 km^2 and coexists with Internet data traffic. This Sagnac interferometer achieves a sensitivity of about 1e-8 (rad/s)/sqrt(Hz), thus approaching ring laser gyroscopes without using narrow-linewidth laser nor sophisticated optics. The proposed gyroscope is sensitive enough for seismic applications, opening new possibilities for this kind of optical fiber sensors
A Silicon Micromachined Gyroscope Driven by the Rotating Carrier Self
Fuxue Zhang; Xu Mao; Yu Liu; Nan Zhang; Wei Zhang
2006-01-01
This paper reported a silicon micromachined gyroscope which is driven by the rotating carrier's angular velocity, the silicon was manufactured by anisotropy etching. The design, fabrication and packing of the sensing element were introduced in the paper. The imitation experimentation and performance test have certificated that the principle of the gyroscope is correct and the gyroscope can be used to sense yawing or pitching angular velocity of the rotating carrier, and the angular velocity of the rotating carrier itself.
System Dynamics and Adaptive Control for MEMS Gyroscope Sensor
Juntao Fei; Hongfei Ding
2011-01-01
This paper presents an adaptive control approach for Micro-Electro-Mechanical Systems (MEMS) z-axis gyroscope sensor. The dynamical model of MEMS gyroscope sensor is derived and adaptive state tracking control for MEMS gyroscope is developed. The proposed adaptive control approaches can estimate the angular velocity and the damping and stiffness coefficients including the coupling terms due to the fabrication imperfection. The stability of the closed-loop systems is established with the propo...
Gyroscopic Inertial Micro-Balance Azimuth Locator (GIMBAL) Project
National Aeronautics and Space Administration — Research Support Instruments, Inc. (RSI) proposes the Gyroscopic Inertial Micro-Balance Azimuth Locator (GIMBAL) program to use an innovative encapsulated spinning...
The development of piezoelectric crystal gyroscopes in China
Chen, Feng-Yu; Qing, Rong-Kang
The operation principles and basic characteristics of a newly-developed vibrating-beam piezoelectric crystal angular rate gyroscope are discussed along with the gyroscope applications. Several applications of piezoelectric gyroscopes are described, including its use as a telemetering sensor, attidude measuring device in automobiles, in geological exploraton drilling, and as a sensing element in ship and aircraft control systems. Specifications are presented for several gyroscopes, including those for two piezoelectric angular rate gyros with different applications (telemetering and control), a typical piezoelectric angular displacement gyro, and a piezoelectric inclinometer.
Applications of Fuzzy Sliding Mode Control for a Gyroscope System
Shih-Chung Chen
2013-01-01
Full Text Available The study proposed the application of the fuzzy sliding mode for a gyroscope system status control. The state response analysis of the gyroscope system revealed highly nonlinear and chaotic subharmonic motions of 2T during state formation. The current study discussed the use of tracking control on the sliding mode control and fuzzy sliding mode control of a gyroscope control system. Consequently, the gyroscope system drives from chaotic motion to periodic motion. The numerical simulation results confirm that the proposed controller provides good system stability and convergence without chattering phenomena.
Chernichenko, V. S.; Bidenko, A. I.; Krobka, N. I.; Tribulev, N. V.; Volyntsev, A. A.
2012-12-01
The first prototypes of superfluid gyroscopes were demonstrated in Saclay in 1996 [1] and in Berkeley in 1997 [2]. These gyroscopes were direct hydrodynamic analogues of electrodynamic rf-SQUIDs, based on superfluid 4He. Analogues of dc-SQUID based on 3He had been worked out in 2001 [3]. The first dc-SQUID on 4He was built in 2005 [4]. Comparing the different technical solutions we are gathering the world experience of superfluid gyro schemes to design own ones.
Split-resonator integrated-post MEMS gyroscope
Bae, Youngsam (Inventor); Hayworth, Ken J. (Inventor); Shcheglov, Kirill V. (Inventor)
2004-01-01
A split-resonator integrated-post vibratory microgyroscope may be fabricated using micro electrical mechanical systems (MEMS) fabrication techniques. The microgyroscope may include two gyroscope sections bonded together, each gyroscope section including resonator petals, electrodes, and an integrated half post. The half posts are aligned and bonded to act as a single post.
Vibration Control of Tower Structure with Multiple Cardan Gyroscopes
Haoxiang He
2017-01-01
Full Text Available Tower structure is sensitive to hurricane and earthquake, and it is easy to generate large deflection and dynamic response. The multiple cardan gyroscope has two rotational degrees of freedom, which can generate strong moments to constrain the two horizontal orthogonal deflections if the rotor operates in high speeds, so the structural dynamic responses can be decreased. Hence, the method of dynamic control of the tower structure under wind load and earthquake action is proposed by using the multiple cardan gyroscopes as the dampers. The dynamic mechanism and the fixed axis principle of the multiple cardan gyroscope are introduced, and the dynamic equation of the gyroscope is established. The damping mechanism of the gyroscope is also described. For the tower structure equipped with the multiple cardan gyroscope dampers, the multidimensional control equation considering torsion effect is established, and the equivalent state space equation is presented. Taking a TV Tower with a number of gyroscope dampers as an analysis example, the structural dynamic responses and damping performance under fluctuating wind loads and earthquake action is studied. The results show that the multiple cardan gyroscope dampers with suitable parameters can effectively decrease the structural vibration in horizontal directions and torsional direction.
Coupled Thermal Field of the Rotor of Liquid Floated Gyroscope
Wang Zhengjun
2015-01-01
Full Text Available Inertial navigation devices include star sensor, GPS, and gyroscope. Optical fiber and laser gyroscopes provide high accuracy, and their manufacturing costs are also high. Magnetic suspension rotor gyroscope improves the accuracy and reduces the production cost of the device because of the influence of thermodynamic coupling. Therefore, the precision of the gyroscope is reduced and drift rate is increased. In this study, the rotor of liquid floated gyroscope, particularly the dished rotor gyroscope, was placed under a thermal field, which improved the measurement accuracy of the gyroscope. A dynamic theory of the rotor of liquid floated gyroscope was proposed, and the thermal field of the rotor was simulated. The maximum stress was in x, 1.4; y, 8.43; min 97.23; and max 154.34. This stress occurred at the border of the dished rotor at a high-speed rotation. The secondary flow reached 5549 r/min, and the generated heat increased. Meanwhile, the high-speed rotation of the rotor was volatile, and the dished rotor movement was unstable. Thus, nanomaterials must be added to reduce the thermal coupling fluctuations in the dished rotor and improve the accuracy of the measurement error and drift rate.
Micromachined dual input axis rate gyroscope
Juneau, Thor Nelson
The need for inexpensive yet reliable angular rate sensors in fields ranging from automotive to consumer electronics has motivated prolific micromachined rate gyroscope research. The vast majority of research has focused on single input axis rate gyroscopes based upon either translational resonance, such as tuning forks, or structural mode resonance, such as vibrating rings. However, this work presents a novel, contrasting approach based on angular resonance of a rotating rigid rotor suspended by torsional springs. The inherent symmetry of the circular design allows angular rate measurement about two axes simultaneously, hence the name micromachined dual-axis rate gyroscope. The underlying theory of operation, mechanical structure design optimization, electrical interface circuitry, and signal processing are described in detail. Several operational versions were fabricated using two different fully integrated surface micromachining processes as proof of concept. The heart of the dual-axis rate gyroscope is a ˜2 mum thick polysilicon disk or rotor suspended above the substrate by a four beam suspension. When this rotor in driven into angular oscillation about the axis perpendicular to the substrate, a rotation rate about the two axes parallel to the substrate invokes an out of plane rotor tilting motion due to Coriolis acceleration. This tilting motion is capacitively measured and on board integrated signal processing provides two output voltages proportional to angular rate input about the two axes parallel to the substrate. The design process begins with the derivation of gyroscopic dynamics. The equations suggest that tuning sense mode frequencies to the drive oscillation frequency can vastly increase mechanical sensitivity. Hence the supporting four beam suspension is designed such that electrostatic tuning can match modes despite process variations. The electrostatic tuning range is limited only by rotor collapse to the substrate when tuning-voltage induced
Structure optimization and simulation analysis of the quartz micromachined gyroscope
Wu, Xuezhong; Wang, Haoxu; Xie, Liqiang; Dong, Peitao
2014-03-01
Structure optimization and simulation analysis of the quartz micromachined gyroscope are reported in this paper. The relationships between the structure parameters and the frequencies of work mode were analysed by finite element analysis. The structure parameters of the quartz micromachined gyroscope were optimized to reduce the difference between the frequencies of the drive mode and the sense mode. The simulation results were proved by testing the prototype gyroscope, which was fabricated by micro-electromechanical systems (MEMS) technology. Therefore, the frequencies of the drive mode and the sense mode can match each other by the structure optimization and simulation analysis of the quartz micromachined gyroscope, which is helpful in the design of the high sensitivity quartz micromachined gyroscope.
Structure optimization and simulation analysis of the quartz micromachined gyroscope
Xuezhong Wu
2014-02-01
Full Text Available Structure optimization and simulation analysis of the quartz micromachined gyroscope are reported in this paper. The relationships between the structure parameters and the frequencies of work mode were analysed by finite element analysis. The structure parameters of the quartz micromachined gyroscope were optimized to reduce the difference between the frequencies of the drive mode and the sense mode. The simulation results were proved by testing the prototype gyroscope, which was fabricated by micro-electromechanical systems (MEMS technology. Therefore, the frequencies of the drive mode and the sense mode can match each other by the structure optimization and simulation analysis of the quartz micromachined gyroscope, which is helpful in the design of the high sensitivity quartz micromachined gyroscope.
Gait event detection during stair walking using a rate gyroscope.
Formento, Paola Catalfamo; Acevedo, Ruben; Ghoussayni, Salim; Ewins, David
2014-01-01
Gyroscopes have been proposed as sensors for ambulatory gait analysis and functional electrical stimulation systems. These applications often require detection of the initial contact (IC) of the foot with the floor and/or final contact or foot off (FO) from the floor during outdoor walking. Previous investigations have reported the use of a single gyroscope placed on the shank for detection of IC and FO on level ground and incline walking. This paper describes the evaluation of a gyroscope placed on the shank for determination of IC and FO in subjects ascending and descending a set of stairs. Performance was compared with a reference pressure measurement system. The absolute mean difference between the gyroscope and the reference was less than 45 ms for IC and better than 135 ms for FO for both activities. Detection success was over 93%. These results provide preliminary evidence supporting the use of a gyroscope for gait event detection when walking up and down stairs.
Gait Event Detection during Stair Walking Using a Rate Gyroscope
Formento, Paola Catalfamo; Acevedo, Ruben; Ghoussayni, Salim; Ewins, David
2014-01-01
Gyroscopes have been proposed as sensors for ambulatory gait analysis and functional electrical stimulation systems. These applications often require detection of the initial contact (IC) of the foot with the floor and/or final contact or foot off (FO) from the floor during outdoor walking. Previous investigations have reported the use of a single gyroscope placed on the shank for detection of IC and FO on level ground and incline walking. This paper describes the evaluation of a gyroscope placed on the shank for determination of IC and FO in subjects ascending and descending a set of stairs. Performance was compared with a reference pressure measurement system. The absolute mean difference between the gyroscope and the reference was less than 45 ms for IC and better than 135 ms for FO for both activities. Detection success was over 93%. These results provide preliminary evidence supporting the use of a gyroscope for gait event detection when walking up and down stairs. PMID:24651724
Fiber optic gyroscopes for vehicle navigation systems
Kumagai, Tatsuya; Soekawa, Hirokazu; Yuhara, Toshiya; Kajioka, Hiroshi; Oho, Shigeru; Sonobe, Hisao
1994-03-01
Fiber optic gyroscopes (FOGs) have been developed for vehicle navigation systems and are used in Toyota Motor Corporation models Mark II, Chaser and Cresta in Japan. Use of FOGs in these systems requires high reliability under a wide range of conditions, especially in a temperature range between -40 and 85 degree(s)C. In addition, a high cost-performance ratio is needed. We have developed optical and electrical systems that are inexpensive and can perform well. They are ready to be mass-produced. FOGs have already been installed in luxury automobiles, and will soon be included in more basic vehicles. We have developed more inexpensive FOGs for this purpose.
Vortex gyroscope imaging of planar superfluids.
Powis, A T; Sammut, S J; Simula, T P
2014-10-17
We propose a robust imaging technique that makes it possible to distinguish vortices from antivortices in quasi-two-dimensional Bose-Einstein condensates from a single image of the density of the atoms. Tilting the planar condensate prior to standard absorption imaging excites a generalized gyroscopic mode of the condensate, revealing the sign and location of each vortex. This technique is anticipated to enable experimental measurement of the incompressible kinetic energy spectrum of the condensate and the observation of a negative-temperature phase transition of the vortex gas, driven by two-dimensional superfluid turbulence.
Microwave gyroscope-novel rotation sensor
Karapetyan, G G
2000-01-01
High performance microwave gyroscope (MG) is theoretically developed for the first time to our knowledge. MG is based on Sagnac effect in microwave ring resonator (RR), where a specially taylored phase shifter (PS) on the basis of surface acoustic waves is inserted. Due to that beat frequency becomes proportional to square (or cubic) root upon rotation rate and therefore hugely increases. In the result MG has few order higher sensitivity and dynamic range than state-of-the-art laser gyros, so it can serve as an advanced rotation sensor in navigation and fundamental sciences.
Er-doped fiber ring laser gyroscopes operating in continuous waves
Jingren Qian; Jue Su; Xuxu Wang; Bing Zhu
2007-01-01
A direction related polarizer was inserted into a ring laser cavity to eliminate one of the two eigen-modes as well as spatial hole burning of the gain medium in a bidirectional Er-doped fiber ring laser. Thus, a fiber ring laser gyroscope (FRLG) operating in continuous wave was demonstrated. A beat signal of over 30-dB noise was observed and a good inear relation between the beat frequency shift and cavity rotation rate was obtained.
Space Station Control Moment Gyroscope Lessons Learned
Gurrisi, Charles; Seidel, Raymond; Dickerson, Scott; Didziulis, Stephen; Frantz, Peter; Ferguson, Kevin
2010-01-01
Four 4760 Nms (3510 ft-lbf-s) Double Gimbal Control Moment Gyroscopes (DGCMG) with unlimited gimbal freedom about each axis were adopted by the International Space Station (ISS) Program as the non-propulsive solution for continuous attitude control. These CMGs with a life expectancy of approximately 10 years contain a flywheel spinning at 691 rad/s (6600 rpm) and can produce an output torque of 258 Nm (190 ft-lbf)1. One CMG unexpectedly failed after approximately 1.3 years and one developed anomalous behavior after approximately six years. Both units were returned to earth for failure investigation. This paper describes the Space Station Double Gimbal Control Moment Gyroscope design, on-orbit telemetry signatures and a summary of the results of both failure investigations. The lessons learned from these combined sources have lead to improvements in the design that will provide CMGs with greater reliability to assure the success of the Space Station. These lessons learned and design improvements are not only applicable to CMGs but can be applied to spacecraft mechanisms in general.
A novel differential frequency micro-gyroscope
Nayfeh, A. H.
2013-07-10
We present a frequency-domain method to measure angular speeds using electrostatic micro-electro-mechanical system actuators. Towards this end, we study a single-axis gyroscope made of a micro-cantilever and a proof-mass coupled to two fixed electrodes. The gyroscope possesses two orthogonal axes of symmetry and identical flexural mode shapes along these axes. We develop the equations of motion describing the coupled bending modes in the presence of electrostatic and Coriolis forces. Furthermore, we derive a consistent closed-form higher-order expression for the natural frequencies of the coupled flexural modes. The closed-form expression is verified by comparing its results to those obtained from numerical integration of the equations of motion. We find that rotations around the beam axis couple each pair of identical bending modes to produce a pair of global modes. They also split their common natural frequency into a pair of closely spaced natural frequencies. We propose the use of the difference between this pair of frequencies, which is linearly proportional to the speed of rotation around the beam axis, as a detector for the angular speed.
A novel artificial fish swarm algorithm for recalibration of fiber optic gyroscope error parameters.
Gao, Yanbin; Guan, Lianwu; Wang, Tingjun; Sun, Yunlong
2015-05-05
The artificial fish swarm algorithm (AFSA) is one of the state-of-the-art swarm intelligent techniques, which is widely utilized for optimization purposes. Fiber optic gyroscope (FOG) error parameters such as scale factors, biases and misalignment errors are relatively unstable, especially with the environmental disturbances and the aging of fiber coils. These uncalibrated error parameters are the main reasons that the precision of FOG-based strapdown inertial navigation system (SINS) degraded. This research is mainly on the application of a novel artificial fish swarm algorithm (NAFSA) on FOG error coefficients recalibration/identification. First, the NAFSA avoided the demerits (e.g., lack of using artificial fishes' pervious experiences, lack of existing balance between exploration and exploitation, and high computational cost) of the standard AFSA during the optimization process. To solve these weak points, functional behaviors and the overall procedures of AFSA have been improved with some parameters eliminated and several supplementary parameters added. Second, a hybrid FOG error coefficients recalibration algorithm has been proposed based on NAFSA and Monte Carlo simulation (MCS) approaches. This combination leads to maximum utilization of the involved approaches for FOG error coefficients recalibration. After that, the NAFSA is verified with simulation and experiments and its priorities are compared with that of the conventional calibration method and optimal AFSA. Results demonstrate high efficiency of the NAFSA on FOG error coefficients recalibration.
A Novel Artificial Fish Swarm Algorithm for Recalibration of Fiber Optic Gyroscope Error Parameters
Yanbin Gao
2015-05-01
Full Text Available The artificial fish swarm algorithm (AFSA is one of the state-of-the-art swarm intelligent techniques, which is widely utilized for optimization purposes. Fiber optic gyroscope (FOG error parameters such as scale factors, biases and misalignment errors are relatively unstable, especially with the environmental disturbances and the aging of fiber coils. These uncalibrated error parameters are the main reasons that the precision of FOG-based strapdown inertial navigation system (SINS degraded. This research is mainly on the application of a novel artificial fish swarm algorithm (NAFSA on FOG error coefficients recalibration/identification. First, the NAFSA avoided the demerits (e.g., lack of using artificial fishes’ pervious experiences, lack of existing balance between exploration and exploitation, and high computational cost of the standard AFSA during the optimization process. To solve these weak points, functional behaviors and the overall procedures of AFSA have been improved with some parameters eliminated and several supplementary parameters added. Second, a hybrid FOG error coefficients recalibration algorithm has been proposed based on NAFSA and Monte Carlo simulation (MCS approaches. This combination leads to maximum utilization of the involved approaches for FOG error coefficients recalibration. After that, the NAFSA is verified with simulation and experiments and its priorities are compared with that of the conventional calibration method and optimal AFSA. Results demonstrate high efficiency of the NAFSA on FOG error coefficients recalibration.
Jieyu Liu
2015-06-01
Full Text Available A signal processing technique is presented to improve the angular rate accuracy of Micro-Electro-Mechanical System (MEMS gyroscope by combining numerous gyroscopes. Based on the conditional correlation between gyroscopes, a dynamic data fusion model is established. Firstly, the gyroscope error model is built through Generalized Autoregressive Conditional Heteroskedasticity (GARCH process to improve overall performance. Then the conditional covariance obtained through dynamic conditional correlation (DCC estimator is used to describe the correlation quantitatively. Finally, the approach is validated by a prototype of the virtual gyroscope, which consists of six-gyroscope array. The experimental results indicate that the weights of gyroscopes change with the value of error. Also, the accuracy of combined rate signal is improved dramatically compared to individual gyroscope. The results indicate that the approach not only improves the accuracy of the MEMS gyroscope, but also discovers the fault gyroscope and eliminates its influence.
System Dynamics and Adaptive Control for MEMS Gyroscope Sensor
Juntao Fei
2011-01-01
Full Text Available This paper presents an adaptive control approach for Micro-Electro-Mechanical Systems (MEMS z-axis gyroscope sensor. The dynamical model of MEMS gyroscope sensor is derived and adaptive state tracking control for MEMS gyroscope is developed. The proposed adaptive control approaches can estimate the angular velocity and the damping and stiffness coefficients including the coupling terms due to the fabrication imperfection. The stability of the closed-loop systems is established with the proposed adaptive control strategy. Numerical simulation is investigated to verify the effectiveness of the proposed control scheme.
Design of a LC-tuned magnetically suspended rotating gyroscope
Jin, Lichuan; Zhang, Huaiwu; Zhong, Zhiyong
2011-04-01
A inductor-capacitor (LC) tuned magnetically suspended rotating gyroscope prototype is designed and analyzed. High permeability ferrite cores are used for providing suspension force, and the rotation system is designed using the switched reluctance motor (SRM) principle. According to the LC-tuned principle, magnetic suspension force expression has been derived. The electromagnetic properties of the gyroscope are simulated by the Ansoft Maxwell software. And our result is expected to be able to serve as a prototype of micro-electromechanical system (MEMS) magnetically suspended rotating gyroscope in future practical applications.
Analysis of mathematical model for micromechanical vibratory wheel gyroscope
LUO Yue-sheng; FAN Chong-jin; TAN Zhen-fan
2003-01-01
By the sketch of structure of MVWG,the working laws of this kind of gyroscope were explained.To the aid of Euler′s Dynamics Equation,a mathematical model of the gyroscope was constructed,and then by the basic working laws of MVWG the model was simplified.Under the conditions of the three axial direction rotations and general rotation,the mathematical model was resolved.And finally by the solutions, the working laws of the gyroscope, the working disparity among all sorts of gyrations and the influences from the gyrations in the axial directions were analysed.
GPS-Aided Gyroscope-Free Inertial Navigation Systems
Park, Sungsu; Tan, Chin-Woo
2002-01-01
A gyroscope-free inertial navigation system uses only accelerometers to compute navigation trajectories. It is a low-cost navigation system, but its output error diverges at a rate that is an order faster than that of a conventional gyroscope-based system. So integration with an external reference system, such as the Global Positioning System, is necessary for long-term navigation applications. In this pa-per, an integrated GPS and gyroscope-free INS system is designed to achieve stable long-...
Development of thin film encapsulation process for piezoresistive MEMS gyroscope with wide gaps
Ayanoor-Vitikkate, Vipin
The gyroscope is an inertial sensor used to measure the angular rate of a rotating object. This helps to determine the pitch and yaw rate of any moving body. A number of applications have been developed for consumer and automotive markets, for e.g. vehicle stability control, navigation assist, roll over detection. These are primarily used in high-end cars, where cost is not a major factor. Other areas where a MEMS Gyro can be used are robotics, camcorder stabilization, virtual reality, and more. Primarily due to cost and the size most of these applications have not reached any significant volume. One reason for this is the relatively high cost of MEMS gyros compared to other MEMS sensors like accelerometers or pressure sensors. Generally the cost of packaging a MEMS sensor is about 85-90% of the total cost. Currently most MEMS based gyroscopes are made using bulk or surface micromachining, after which they are packaged using wafer bonding. This unfortunately leads to wastage of silicon and increase in the package size, thus reducing the yield. One way to reduce the cost of packaging is by wafer scale thin film encapsulation of MEMS gyroscopes. The goal of the present work is to fabricate a rate grade MEMS gyroscope and encapsulate it by modifying an existing thin-film encapsulation technique. Packaging is an important step towards commercialization of the device and we plan to use thin wafer scale encapsulation technique developed previously in our group to package these devices. The silicon micro machined gyroscope will be fabricated on SOI (Silicon-on-Insulator) wafers using Bosch DRIE etching techniques. The encapsulation of the device is carried out using epitaxial polysilicon in order to provide a high vacuum inside the device chamber. The advantages offered by this technique are the reduction in area of the die and thus less silicon surface is wasted. In addition to this the encapsulation technique helps in creating a vacuum inside the micro device, which
Gyroscopic g factor of rare earth metals
Ogata, Y.; Chudo, H.; Ono, M.; Harii, K.; Matsuo, M.; Maekawa, S.; Saitoh, E.
2017-02-01
We develop the in situ magnetization measurement apparatus for observing the Barnett effect consisting of a fluxgate sensor, a high speed rotor with frequencies of up to 1.5 kHz, and a magnetic shield at room temperature. The effective magnetic field (Barnett field) in a sample arising from rotation magnetizes the sample and is proportional to the rotational frequency. The gyroscopic g factor, g ' , of rare earth metals, in particular, Gd, Tb, and Dy, was estimated to be 2.00 ± 0.08, 1.53 ± 0.17, and 1.15 ± 0.32, respectively, from the slopes of the rotation dependence of the Barnett field. This study provides a technique to determine the g ' factor even in samples where the spectroscopic method may not be available.
Solid-state ring laser gyroscope
Schwartz, S.
The ring laser gyroscope is a rotation sensor used in most kinds of inertial navigation units. It usually consists in a ring cavity filled with a mixture of helium and neon, together with high-voltage pumping electrodes. The use of a gaseous gain medium, while resulting naturally in a stable bidirectional regime enabling rotation sensing, is however the main industrially limiting factor for the ring laser gyroscopes in terms of cost, reliability and lifetime. We study in this book the possibility of substituting for the gaseous gain medium a solid-state medium (diode-pumped Nd-YAG). For this, a theoretical and experimental overview of the lasing regimes of the solid-state ring laser is reported. We show that the bidirectional emission can be obtained thanks to a feedback loop acting on the states of polarization and inducing differential losses proportional to the difference of intensity between the counterpropagating modes. This leads to the achievement of a solid-state ring laser gyroscope, whose frequency response is modified by mode coupling effects. Several configurations, either mechanically or optically based, are then successively studied, with a view to improving the quality of this frequency response. In particular, vibration of the gain crystal along the longitudinal axis appears to be a very promising technique for reaching high inertial performances with a solid-state ring laser gyroscope. Gyrolaser à état solide. Le gyrolaser est un capteur de rotation utilisé dans la plupart des centrales de navigation inertielle. Dans sa forme usuelle, il est constitué d'une cavité laser en anneau remplie d'un mélange d'hélium et de néon pompé par des électrodes à haute tension. L'utilisation d'un milieu amplificateur gazeux, si elle permet de garantir naturellement le fonctionnement bidirectionnel stable nécessaire à la mesure des rotations, constitue en revanche la principale limitation industrielle des gyrolasers actuels en termes de coût, fiabilit
Educators' relational experiences with learners identified with fetal ...
Educators' relational experiences with learners identified with fetal alcohol ... is an integral aspect of the learning environment, relational functioning within this ... the negative impact of these experiences on educators' personal resources and ...
Reproducibility of a 3-dimensional gyroscope in measuring shoulder anteflexion and abduction
Penning Ludo I F
2012-07-01
Full Text Available Abstract Background Few studies have investigated the use of a 3-dimensional gyroscope for measuring the range of motion (ROM in the impaired shoulder. Reproducibility of digital inclinometer and visual estimation is poor. This study aims to investigate the reproducibility of a tri axial gyroscope in measurement of anteflexion, abduction and related rotations in the impaired shoulder. Methods Fifty-eight patients with either subacromial impingement (27 or osteoarthritis of the shoulder (31 participated. Active anteflexion, abduction and related rotations were measured with a tri axial gyroscope according to a test retest protocol. Severity of shoulder impairment and patient perceived pain were assessed by the Disability of Arm Shoulder and Hand score (DASH and the Visual Analogue Scale (VAS. VAS scores were recorded before and after testing. Results In two out of three hospitals patients with osteoarthritis (n = 31 were measured, in the third hospital patients with subacromial impingement (n = 27. There were significant differences among hospitals for the VAS and DASH scores measured before and after testing. The mean differences between the test and retest means for anteflexion were −6 degrees (affected side, 9 (contralateral side and for abduction 15 degrees (affected side and 10 degrees (contralateral side. Bland & Altman plots showed that the confidence intervals for the mean differences fall within −6 up to 15 degrees, individual test - retest differences could exceed these limits. A simulation according to ‘Generalizability Theory’ produces very good coefficients for anteflexion and related rotation as a comprehensive measure of reproducibility. Optimal reproducibility is achieved with 2 repetitions for anteflexion. Conclusions Measurements were influenced by patient perceived pain. Differences in VAS and DASH might be explained by different underlying pathology. These differences in shoulder pathology however did not alter
The carrier-generating analysis of MEMS gyroscope interface circuit
GuangMin Yuan
2014-03-01
Full Text Available In this paper, the main factors which influence the noise ratio of gyroscope output signal were analysed, according to the MEMS gyro interface circuit technology. A working principle of a carrier in the gyroscope circuit was discussed, the process formula of the carrier amplitude and frequency in the interface circuit of modulation and demodulation was deduced, and the error components lead-in from carrier to gyroscope circuit was distinguished. Several commonly used carrier-generating circuit schemes were analysed and compared, and a carrier-generating program in the interface circuits of the micro-gyroscope was designed, which was applied in a MEMS gyro developed by our laboratory. The measurement results show that the amplitude stability and frequency stability is 1.3 ppm and 12 ppm, respectively, meeting the performance requirements of carrier generating in the MEMS gyro circuit.
Temperature Dependent Characteristics of the JPL Silcon MEMS Gyroscope
Shcheglov, K.; Evans, C.; Gutierrez, R.; Tang, T.
2000-01-01
Advances in aeronautics and space technology have created a need for miniaturized navigation instruments such as gyroscopes, a need wich is currently beig addressed by a number of micromachined designs.
The carrier-generating analysis of MEMS gyroscope interface circuit
Yuan, GuangMin; Yuan, Weizheng; Zhu, Xiaobo; Chang, HongLong
2014-03-01
In this paper, the main factors which influence the noise ratio of gyroscope output signal were analysed, according to the MEMS gyro interface circuit technology. A working principle of a carrier in the gyroscope circuit was discussed, the process formula of the carrier amplitude and frequency in the interface circuit of modulation and demodulation was deduced, and the error components lead-in from carrier to gyroscope circuit was distinguished. Several commonly used carrier-generating circuit schemes were analysed and compared, and a carrier-generating program in the interface circuits of the micro-gyroscope was designed, which was applied in a MEMS gyro developed by our laboratory. The measurement results show that the amplitude stability and frequency stability is 1.3 ppm and 12 ppm, respectively, meeting the performance requirements of carrier generating in the MEMS gyro circuit.
Dual axis operation of a micromachined rate gyroscope
Juneau, T. [BSAC, Berkeley, CA (United States); Pisano, A.P. [Univ. California, Berkeley, CA (United States). Dept. of Mechanical Engineering; Smith, J. [Sandia National Lab., Albuquerque, NM (United States)
1997-04-01
Since micromachining technology has raised the prospect of fabricating high performance sensors without the associated high cost and large size, many researchers have investigated micromachined rate gyroscopes. The vast majority of research has focused on single input axis rate gyroscopes, but this paper presents work on a dual input axis micromachined rate gyroscope. The key to successful simultaneous dual axis operation is the quad symmetry of the circular oscillating rotor design. Untuned gyroscopes with mismatched modes yielded random walk as low as 10{degrees}/{radical}hour with cross sensitivity ranging from 6% to 16%. Mode frequency matching via electrostatic tuning allowed performance better than 2{degrees}/{radical}hour, but at the expense of excessive cross sensitivity.
Modification of piezoelectric vibratory gyroscope resonator parameters by feedback control
Loveday, PW
1998-09-01
Full Text Available A method for analyzing the effect of feedback control on the dynamics of piezoelectric resonators used in vibratory gyroscopes has been developed. This method can be used to determine the feasibility of replacing the traditional mechanical balancing...
Miniature, Variable-Speed Control Moment Gyroscope Project
National Aeronautics and Space Administration — The overall goal of this project is to design, develop, demonstrate, and deliver a miniature, variable speed control moment gyroscope (MVS CMG) for use on small...
Dynamics of an all-optical atomic spin gyroscope.
Fang, Jiancheng; Wan, Shuangai; Yuan, Heng
2013-10-20
We present the transfer function of an all-optical atomic spin gyroscope through a series of differential equations and validate the transfer function by experimental test. A transfer function is the basis for further control system design. We build the differential equations based on a complete set of Bloch equations describing the all-optical atomic spin gyroscope, and obtain the transfer function through application of the Laplace transformation to these differential equations. Moreover, we experimentally validate the transfer function in an all-optical Cs-Xe129 atomic spin gyroscope through a series of step responses. This transfer function is convenient for analysis of the form of control system required. Furthermore, it is available for the design of the control system specifically to improve the performance of all-optical atomic spin gyroscopes.
Surface Roughness Effects on Vortex Torque of Air Supported Gyroscope
LIANG Yingchun; LIU Jingshi; SUN Yazhou; LU Lihua
2011-01-01
In order to improve the drift precision of air supported gyroscope, effects of surface roughness magnitude and direction on vortex torque of air supported gyroscope are studied. Based on Christensen's rough surface stochastic model and consistency transformation method, Reynolds equation of air supported gyroscope containing surface roughness information is established.Also effects of mathematical models of main machining errors on vortex torque are established. By using finite element method,the Reynolds equation is solved numerically and the vortex torque in the presence of machining errors and surface roughness is calculated. The results show that surface roughness of slit has a significant effect on vortex torque. Transverse surface roughness makes vortex torque greater, while longitudinal surface roughness makes vortex torque smaller. The maximal difference approaches 11.4％ during the range analyzed in this article. However surface roughness of journal influences vortex torque insignificantly. The research is of great significance for designing and manufacturing air supported gyroscope and predicting its performance.
Resonant microsphere gyroscope based on a double Faraday rotator system.
Xie, Chengfeng; Tang, Jun; Cui, Danfeng; Wu, Dajin; Zhang, Chengfei; Li, Chunming; Zhen, Yongqiu; Xue, Chenyang; Liu, Jun
2016-10-15
The resonant microsphere gyroscope is proposed based on a double Faraday rotator system for the resonant microsphere gyroscope (RMSG) that is characterized by low insertion losses and does not destroy the reciprocity of the gyroscope system. Use of the echo suppression structure and the orthogonal polarization method can effectively inhibit both the backscattering noise and the polarization error, and reduce them below the system sensitivity limit. The resonance asymmetry rate dropped from 34.2% to 2.9% after optimization of the backscattering noise and the polarization noise, which greatly improved the bias stability and the scale factor linearity of the proposed system. Additionally, based on the optimum parameters for the double Faraday rotator system, a bias stability of 0.04°/s has been established for an integration time of 10 s in 1000 s in a resonator microsphere gyroscope using a microsphere resonator with a diameter of 1 mm and a Q of 7.2×106.
李金涛; 房建成
2011-01-01
惯性测量单元(IMU)是位置姿态系统(POS)的核心部分,IMU的精度很大程度上决定着POS精度.由于高精度光纤陀螺(FOG)的光纤线圈对磁场敏感,基于高精度FOG的IMU精度会受磁场影响而降低.本文研究了FOG磁敏感性机理,通过实验得出高精度光纤IMU对磁场敏感的结论.采用电磁场有限元分析软件Ansoft Maxwell研究了磁屏蔽体采用不同材料、不同厚度时的磁屏蔽效能(SE),并进行了IMU磁屏蔽结构设计.通过亥姆霍兹线圈测试得到的磁屏蔽体实际屏蔽效能最高为48.20 dB,与有限元分析结果基本一致.转台环境测试表明:屏蔽体使FOG漂移减小到9％以上；亥姆霍兹线圈测试表明:通过磁屏蔽使FOG零偏磁敏感度衰减2～21 dB,漂移磁敏感度衰减9～23 dB,对提高光纤IMU测试和应用精度以及机载环境适应性有重要意义.%The inertial measurement unit (IMU) is the core of a position and orientation system (POS), whose accuracy has a crucial impact on POS accuracy. But the IMU accuracy based on high precision fiber-optic gyroscope (FOG) is degraded because of the sensitivity of the FOG fiber coil to the magnetic field. This paper studied the magnetic sensitivity mechanism of the FOG. And through experimental study reached the conclusion that the IMU based on a high precision FOG is also sensitive to the magnetic field. An IMU shielding is designed, and its shielding effectiveness (SE) is analyzed by electromagnetic field finite element analysis software Ansoft Maxwell for different materials with different thicknesses. The best SE of 48.20 Db is achieved with a Helmholtz coil test, which is consistent with the results of the finite element analysis. The turn table test shows that a reduction of over 9% of the FOG drift is achieved with the enclosure. The Helmholtz coil test with magnetic shielding demonstrates that the bias and drift magnetic sensitivity of the FOG are decreased by 2-21 Db and 9-23 Db
Structural-Acoustic Coupling Effects on the Non-Vacuum Packaging Vibratory Cylinder Gyroscope
Xiang Xi
2013-12-01
Full Text Available The resonant shells of vibratory cylinder gyroscopes are commonly packaged in metallic caps. In order to lower the production cost, a portion of vibratory cylinder gyroscopes do not employ vacuum packaging. However, under non-vacuum packaging conditions there can be internal acoustic noise leading to considerable acoustic pressure which is exerted on the resonant shell. Based on the theory of the structural-acoustic coupling, the dynamical behavior of the resonant shell under acoustic pressure is presented in this paper. A finite element (FE model is introduced to quantitatively analyze the effect of the structural-acoustic coupling. Several main factors, such as sealing cap sizes and degree of vacuum which directly affect the vibration of the resonant shell, are studied. The results indicate that the vibration amplitude and the operating frequency of the resonant shell will be changed when the effect of structural-acoustic coupling is taken into account. In addition, an experiment was set up to study the effect of structural-acoustic coupling on the sensitivity of the gyroscope. A 32.4 mV/°/s increase of the scale factor and a 6.2 Hz variation of the operating frequency were observed when the radial gap size between the resonant shell and the sealing cap was changed from 0.5 mm to 20 mm.
Structural-acoustic coupling effects on the non-vacuum packaging vibratory cylinder gyroscope.
Xi, Xiang; Wu, Xuezhong; Wu, Yulie; Zhang, Yongmeng; Tao, Yi; Zheng, Yu; Xiao, Dingbang
2013-12-13
The resonant shells of vibratory cylinder gyroscopes are commonly packaged in metallic caps. In order to lower the production cost, a portion of vibratory cylinder gyroscopes do not employ vacuum packaging. However, under non-vacuum packaging conditions there can be internal acoustic noise leading to considerable acoustic pressure which is exerted on the resonant shell. Based on the theory of the structural-acoustic coupling, the dynamical behavior of the resonant shell under acoustic pressure is presented in this paper. A finite element (FE) model is introduced to quantitatively analyze the effect of the structural-acoustic coupling. Several main factors, such as sealing cap sizes and degree of vacuum which directly affect the vibration of the resonant shell, are studied. The results indicate that the vibration amplitude and the operating frequency of the resonant shell will be changed when the effect of structural-acoustic coupling is taken into account. In addition, an experiment was set up to study the effect of structural-acoustic coupling on the sensitivity of the gyroscope. A 32.4 mV/°/s increase of the scale factor and a 6.2 Hz variation of the operating frequency were observed when the radial gap size between the resonant shell and the sealing cap was changed from 0.5 mm to 20 mm.
Design and Application of Quadrature Compensation Patterns in Bulk Silicon Micro-Gyroscopes
Yunfang Ni
2014-10-01
Full Text Available This paper focuses on the detailed design issues of a peculiar quadrature reduction method named system stiffness matrix diagonalization, whose key technology is the design and application of quadrature compensation patterns. For bulk silicon micro-gyroscopes, a complete design and application case was presented. The compensation principle was described first. In the mechanical design, four types of basic structure units were presented to obtain the basic compensation function. A novel layout design was proposed to eliminate the additional disturbing static forces and torques. Parameter optimization was carried out to maximize the available compensation capability in a limited layout area. Two types of voltage loading methods were presented. Their influences on the sense mode dynamics were analyzed. The proposed design was applied on a dual-mass silicon micro-gyroscope developed in our laboratory. The theoretical compensation capability of a quadrature equivalent angular rate no more than 412 °/s was designed. In experiments, an actual quadrature equivalent angular rate of 357 °/s was compensated successfully. The actual compensation voltages were a little larger than the theoretical ones. The correctness of the design and the theoretical analyses was verified. They can be commonly used in planar linear vibratory silicon micro-gyroscopes for quadrature compensation purpose.
Temperature drift modeling of MEMS gyroscope based on genetic-Elman neural network
Chong, Shen; Rui, Song; Jie, Li; Xiaoming, Zhang; Jun, Tang; Yunbo, Shi; Jun, Liu; Huiliang, Cao
2016-05-01
In order to improve the temperature drift modeling precision of a tuning fork micro-electromechanical system (MEMS) gyroscope, a novel multiple inputs/single output model based on genetic algorithm (GA) and Elman neural network (Elman NN) is proposed. First, the temperature experiment of MEMS gyroscope is carried out and the outputs of MEMS gyroscope and temperature sensors are collected; then the temperature drift model based on temperature, temperature variation rate and the coupling term is proposed, and the Elman NN is employed to guarantee the generalization ability of the model; at last the genetic algorithm is used to tune the parameters of Elman NN in order to improve the modeling precision. The Allan analysis results validate that, compared to traditional single input/single output model, the novel multiple inputs/single output model can guarantee high accurate fitting ability because the proposed model can provide more plentiful controllable information. By the way, the generalization ability of the Elman neural network can be improved significantly due to the parameters are optimized by genetic algorithm.
Scale Factor Measurements for a Gyroscope Based on an Expanding Cloud of Atoms
Hoth, Gregory; Pelle, Bruno; Riedl, Stefan; Kitching, John; Donley, Elizabeth
2016-05-01
We present an atom interferometer that can simultaneously measure two-axis rotations and one-axis accelerations with a single cloud of atoms in an active evacuated volume of about 1 cm3. This is accomplished by extending the point-source interferometry technique (Dickerson et al. PRL, 111, 083001, 2013) to a compact regime. In this technique, the cloud of atoms is imaged after the interferometer sequence. Rotations cause spatial fringes to appear across the cloud. To realize a gyroscope with this method, it is necessary to know how the wave-vector of the spatial fringes, k, is related to the rotation rate, Ω. If the cloud is initially infinitesimally small, it can be shown that k = FΩ with a scale factor F determined by the time between interferometer pulses, the total free expansion time, and the wavelength of the interrogating laser. However, the point-source approximation is not appropriate in our case because the final size of the cloud in our experiment is between 1.4 and 5 times its initial size. We show experimentally that in this finite expansion regime the phase gradient is still well described by k = FΩ , but the scale factor F depends on the initial distribution of the atoms. We also present modeling that explains this dependence.
Gyroscope based on a crystalline optical WGM microresonator (Conference Presentation)
Liang, Wei; Ilchenko, Vladimir S.; Eliyahu, Danny; Savchenkov, Anatoliy A.; Matsko, Andrey B.; Maleki, Lute
2017-02-01
We report on a study of performance of both active and passive optical gyroscopes based on high finesse crystalline whispering gallery mode (WGM) resonators. We show that the sensitivity of the devices is ultimately limited due to the nonlinearity of the resonator host material. A gyroscope characterized with 0.02 deg/hr^1/2 angle random walk and 2 deg/hr bias drift is demonstrated.
Ring-laser gyroscope system using dispersive element(s)
Smith, David D. (Inventor)
2010-01-01
A ring-laser gyroscope system includes a ring-laser gyroscope (RLG) and at least one dispersive element optically coupled to the RLG's ring-shaped optical path. Each dispersive element has a resonant frequency that is approximately equal to the RLG's lasing frequency. A group index of refraction defined collectively by the dispersive element(s) has (i) a real portion that is greater than zero and less than one, and (ii) an imaginary portion that is less than zero.
Optimal design of SAW-based gyroscope to improve sensitivity
Oh, Haekwan; Yang, Sangsik; Lee, Keekeun
2010-02-01
A surface acoustic wave (SAW)-based gyroscope was developed on a piezoelectric substrate. The developed gyroscope consists of two SAW oscillators, metallic dots, and absorber. Coupling of mode (COM) modeling was conducted to determine the optimal device parameters prior to fabrication. Depending on the angular velocity, the difference of the oscillation frequency was modulated. The obtained sensitivity was approximately 52.35 Hz/deg.s at an angular rate range of 0~1000 deg/s.
Relation of validation experiments to applications.
Hamilton, James R. (New Mexico State University, Las Cruces, NM); Hills, Richard Guy
2009-02-01
Computational and mathematical models are developed in engineering to represent the behavior of physical systems to various system inputs and conditions. These models are often used to predict at other conditions, rather than to just reproduce the behavior of data obtained at the experimental conditions. For example, the boundary or initial conditions, time of prediction, geometry, material properties, and other model parameters can be different at test conditions than those for an anticipated application of a model. Situations for which the conditions may differ include those for which (1) one is in the design phase and a prototype of the system has not been constructed and tested under the anticipated conditions, (2) only one version of a final system can be built and destructive testing is not feasible, or (3) the anticipated design conditions are variable and one cannot easily reproduce the range of conditions with a limited number of carefully controlled experiments. Because data from these supporting experiments have value in model validation, even if the model was tested at different conditions than an anticipated application, methodology is required to evaluate the ability of the validation experiments to resolve the critical behavior for the anticipated application. The methodology presented uses models for the validation experiments and a model for the application to address how well the validation experiments resolve the application. More specifically, the methodology investigates the tradeoff that exists between the uncertainty (variability) in the behavior of the resolved critical variables for the anticipated application and the ability of the validation experiments to resolve this behavior. The important features of this approach are demonstrated through simple linear and non-linear heat conduction examples.
Initial Test Results from a 3-axis Vibrating Ring Gyroscope
Gallacher, B J; Neasham, J A; Burdess, J S; Harris, A J [INSAT University of Newcastle upon Tyne NE1 7RU (United Kingdom)
2006-04-01
There are several application areas where the simultaneous measurement of rates of rotation about three mutually orthogonal axes is required. In this paper the principle features of a 3-axis vibrating ring gyroscope are described. The fabrication process for the gyroscope is presented and employs standard MEMS techniques. The modal properties for the ring are measured experimentally using laser vibrometry and electrostatic sensing and compared with the design predictions. In operation as a rate gyroscope it is necessary to excite the primary motion of the gyroscope and control is amplitude. As Q-factors of vibratory gyroscope are typically of the order 10{sup 3}-10{sup 4} slight variations in environmental conditions will perturb the natural frequency of the primary mode significantly. To ensure the primary motion of the gyroscope is maintained with constant amplitude a control scheme employing both frequency tracking and amplitude control is required. An electronic control system using digital signal processing (DSP) has been developed to ensure excitation of the primary motion occurs at resonance with controlled amplitude. The control scheme employs an embedded processor to generate the drive frequency (via a D/A converter) and to monitor the primary vibration (via an A/D converter). Experimental results from the control scheme highlighting its effectiveness over conventional PLL approaches are presented.
Stellar Gyroscope for Determining Attitude of a Spacecraft
Pain, Bedabrata; Hancock, Bruce; Liebe, Carl; Mellstrom, Jeffrey
2005-01-01
A paper introduces the concept of a stellar gyroscope, currently at an early stage of development, for determining the attitude or spin axis, and spin rate of a spacecraft. Like star trackers, which are commercially available, a stellar gyroscope would capture and process images of stars to determine the orientation of a spacecraft in celestial coordinates. Star trackers utilize chargecoupled devices as image detectors and are capable of tracking attitudes at spin rates of no more than a few degrees per second and update rates typically gyroscope would utilize an activepixel sensor as an image detector and would be capable of tracking attitude at a slew rate as high as 50 deg/s, with an update rate as high as 200 Hz. Moreover, a stellar gyroscope would be capable of measuring a slew rate up to 420 deg/s. Whereas a Sun sensor and a three-axis mechanical gyroscope are typically needed to complement a star tracker, a stellar gyroscope would function without them; consequently, the mass, power consumption, and mechanical complexity of an attitude-determination system could be reduced considerably.
The fiber optic gyroscope - a portable rotational ground motion sensor
Wassermann, J. M.; Bernauer, F.; Guattari, F.; Igel, H.
2016-12-01
It was already shown that a portable broadband rotational ground motion sensor will have large impact on several fields of seismological research such as volcanology, marine geophysics, seismic tomography and planetary seismology. Here, we present results of tests and experiments with one of the first broadband rotational motion sensors available. BlueSeis-3A, is a fiber optic gyroscope (FOG) especially designed for the needs of seismology, developed by iXBlue, France, in close collaboration with researchers financed by the European Research council project ROMY (Rotational motions - a new observable for seismology). We first present the instrument characteristics which were estimated by different standard laboratory tests, e.g. self noise using operational range diagrams or Allan deviation. Next we present the results of a field experiment which was designed to demonstrate the value of a 6C measurement (3 components of translation and 3 components of rotation). This field test took place at Mt. Stromboli volcano, Italy, and is accompanied by seismic array installation to proof the FOG output against more commonly known array derived rotation. As already shown with synthetic data an additional direct measurement of three components of rotation can reduce the ambiguity in source mechanism estimation and can be taken to correct for dynamic tilt of the translational sensors (i.e. seismometers). We can therefore demonstrate that the deployment of a weak motion broadband rotational motion sensor is in fact producing superior results by a reduction of the number of deployed instruments.
Molecular quantum rotors in gyroscopic motion with a nonspreading rotational wavepacket
Yun, Sang Jae
2015-01-01
We provide a way of generating and observing molecular quantum gyroscopic motion that resembles gyroscopic motion of classical rotors. After producing a nonspreading rotational wavepacket called a cogwheel state, one can generate a gyroscopic precession motion by applying an external magnetic field interacting through a rotational magnetic dipole moment. The quantum rotors, realized with linear nonparamagnetic ionic molecules trapped in an ion trap, can keep their gyroscopic motion for a long time in a collectively synchronized fashion. A Coulomb-explosion technique is suggested to observe the gyroscopic motion. Despite limited molecular species, the observation of the gyroscopic motion can be adopted as a method to measure rotational g factors of molecules.
Parallel Relational Universes – experiments in modularity
Pagliarini, Luigi; Lund, Henrik Hautop
2015-01-01
: We here describe Parallel Relational Universes, an artistic method used for the psychological analysis of group dynamics. The design of the artistic system, which mediates group dynamics, emerges from our studies of modular playware and remixing playware. Inspired from remixing modular playware......, where users remix samples in the form of physical and functional modules, we created an artistic instantiation of such a concept with the Parallel Relational Universes, allowing arts alumni to remix artistic expressions. Here, we report the data emerged from a first pre-test, run with gymnasium’s alumni...
Online technique for detecting state of onboard fiber optic gyroscope.
Miao, Zhiyong; Xu, Dingjie; He, Kunpeng; Pang, Shuwan; Tian, Chunmiao
2015-02-01
Although angle random walk (ARW) of fiber optic gyroscope (FOG) has been well modeled and identified before being integrated into the high-accuracy attitude control system of satellite, aging and unexpected failures can affect the performance of FOG after launch, resulting in the variation of ARW coefficient. Therefore, the ARW coefficient can be regarded as an indicator of "state of health" for FOG diagnosis in some sense. The Allan variance method can be used to estimate ARW coefficient of FOG, however, it requires a large amount of data to be stored. Moreover, the procedure of drawing slope lines for estimation is painful. To overcome the barriers, a weighted state-space model that directly models the ARW to obtain a nonlinear state-space model was established for FOG. Then, a neural extended-Kalman filter algorithm was implemented to estimate and track the variation of ARW in real time. The results of experiment show that the proposed approach is valid to detect the state of FOG. Moreover, the proposed technique effectively avoids the storage of data.
Online technique for detecting state of onboard fiber optic gyroscope
Miao, Zhiyong; He, Kunpeng, E-mail: pengkhe@126.com; Pang, Shuwan [Department of Automation, Harbin Engineering University, Harbin, Heilongjiang 150000 (China); Xu, Dingjie [School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin, Heilongjiang 150000 (China); Tian, Chunmiao [Department of Information and Communication Engineering, Harbin Engineering University, Harbin, Heilongjiang 150000 (China)
2015-02-15
Although angle random walk (ARW) of fiber optic gyroscope (FOG) has been well modeled and identified before being integrated into the high-accuracy attitude control system of satellite, aging and unexpected failures can affect the performance of FOG after launch, resulting in the variation of ARW coefficient. Therefore, the ARW coefficient can be regarded as an indicator of “state of health” for FOG diagnosis in some sense. The Allan variance method can be used to estimate ARW coefficient of FOG, however, it requires a large amount of data to be stored. Moreover, the procedure of drawing slope lines for estimation is painful. To overcome the barriers, a weighted state-space model that directly models the ARW to obtain a nonlinear state-space model was established for FOG. Then, a neural extended-Kalman filter algorithm was implemented to estimate and track the variation of ARW in real time. The results of experiment show that the proposed approach is valid to detect the state of FOG. Moreover, the proposed technique effectively avoids the storage of data.
Effect of 60Co-gamma radiation on the random walk error of interferometric fiber optic gyroscopes
无
2010-01-01
Two 60Co-gamma radiation experiments were launched to explore the radiation effect on optical components and interferometric fiber optic gyroscope （IFOG）. In optical components radiation experiment, the result showed that polarization-maintaining （PM） fiber coil loss was the most affected parameter in all the RWC （random walk coefficient） related parameters, compared with the weak sensitivity of other components parameters. In the IFOG radiation experiment, the RWC performance degradation was found to be almost due to an increase of the PM fiber attenuation. Based on the experiment result, a RWC prediction model in radiation, which is obtained by embedding PM fiber loss expression into the RWC model, was built following a power law of dose and dose rate. An IFOG RWC in space radiation environment was predicted from radiation dose and dose rate by the RWC prediction model. This RWC value calculated from test data is fully accorded to the RWC value predicted from radiation dose.
Gyroscopic stabilization and indefimite damped systems
Pommer, Christian
a class of feasibel skew-Hermitian matrices A depending on the choise of M. The theory can be applied to dynamical systems of the form x''(t) + ( dD + g G) x'(t) + K x(t) = 0 where G is a skew symmetric gyrocopic matrix, D is a symmetric indefinite damping matrix and K > 0 is a positive definite stiffness......An important issue is how to modify a given unstable matrix in such a way that the resulting matrix is stable. We investigate in general under which condition a matrix M+A is stable,where M is an arbitrary matrix and A is skew-Hermitian. We show that if trace(M) > 0 it is always possible to find...... matrix. d and g are scaling factors used to control the stability of the system. It is quite astonnishing that when the damping matrix D is indefinite the system can under certain conditions be stable even if there are no gyroscopic forces G present The Lyapunov matrix equation is used to predict...
Modeling and optimizing of the random atomic spin gyroscope drift based on the atomic spin gyroscope
Quan, Wei; Lv, Lin; Liu, Baiqi
2014-11-01
In order to improve the atom spin gyroscope's operational accuracy and compensate the random error caused by the nonlinear and weak-stability characteristic of the random atomic spin gyroscope (ASG) drift, the hybrid random drift error model based on autoregressive (AR) and genetic programming (GP) + genetic algorithm (GA) technique is established. The time series of random ASG drift is taken as the study object. The time series of random ASG drift is acquired by analyzing and preprocessing the measured data of ASG. The linear section model is established based on AR technique. After that, the nonlinear section model is built based on GP technique and GA is used to optimize the coefficients of the mathematic expression acquired by GP in order to obtain a more accurate model. The simulation result indicates that this hybrid model can effectively reflect the characteristics of the ASG's random drift. The square error of the ASG's random drift is reduced by 92.40%. Comparing with the AR technique and the GP + GA technique, the random drift is reduced by 9.34% and 5.06%, respectively. The hybrid modeling method can effectively compensate the ASG's random drift and improve the stability of the system.
Modeling and optimizing of the random atomic spin gyroscope drift based on the atomic spin gyroscope
Quan, Wei; Lv, Lin, E-mail: lvlinlch1990@163.com; Liu, Baiqi [School of Instrument Science and Opto-Electronics Engineering, Beihang University, Beijing 100191 (China)
2014-11-15
In order to improve the atom spin gyroscope's operational accuracy and compensate the random error caused by the nonlinear and weak-stability characteristic of the random atomic spin gyroscope (ASG) drift, the hybrid random drift error model based on autoregressive (AR) and genetic programming (GP) + genetic algorithm (GA) technique is established. The time series of random ASG drift is taken as the study object. The time series of random ASG drift is acquired by analyzing and preprocessing the measured data of ASG. The linear section model is established based on AR technique. After that, the nonlinear section model is built based on GP technique and GA is used to optimize the coefficients of the mathematic expression acquired by GP in order to obtain a more accurate model. The simulation result indicates that this hybrid model can effectively reflect the characteristics of the ASG's random drift. The square error of the ASG's random drift is reduced by 92.40%. Comparing with the AR technique and the GP + GA technique, the random drift is reduced by 9.34% and 5.06%, respectively. The hybrid modeling method can effectively compensate the ASG's random drift and improve the stability of the system.
Quan, Wei; Lv, Lin; Liu, Baiqi
2014-11-01
In order to improve the atom spin gyroscope's operational accuracy and compensate the random error caused by the nonlinear and weak-stability characteristic of the random atomic spin gyroscope (ASG) drift, the hybrid random drift error model based on autoregressive (AR) and genetic programming (GP) + genetic algorithm (GA) technique is established. The time series of random ASG drift is taken as the study object. The time series of random ASG drift is acquired by analyzing and preprocessing the measured data of ASG. The linear section model is established based on AR technique. After that, the nonlinear section model is built based on GP technique and GA is used to optimize the coefficients of the mathematic expression acquired by GP in order to obtain a more accurate model. The simulation result indicates that this hybrid model can effectively reflect the characteristics of the ASG's random drift. The square error of the ASG's random drift is reduced by 92.40%. Comparing with the AR technique and the GP + GA technique, the random drift is reduced by 9.34% and 5.06%, respectively. The hybrid modeling method can effectively compensate the ASG's random drift and improve the stability of the system.
TEGUH PERKASA
2017-01-01
part and lower part of leg. The data is then processed into value-based knee angle using Arduino controller. All three system were tested to measure the lower limb angle and the upper limb angel. The results showed that error angle measurment of the lower limb and upper limb are 3 degrees and 2 degrees, respectively, relative to a goniometer measurement as a standard non electronics tool to measure the knee angle. In addition, the data was also successfully transferred wirelessly.Keywords: Arduino, Gyroscope, Radio Frequency, Knee angle, Wireless.
Jieyu Liu; Qiang Shen; Weiwei Qin
2015-01-01
A signal processing technique is presented to improve the angular rate accuracy of Micro-Electro-Mechanical System (MEMS) gyroscope by combining numerous gyroscopes. Based on the conditional correlation between gyroscopes, a dynamic data fusion model is established. Firstly, the gyroscope error model is built through Generalized Autoregressive Conditional Heteroskedasticity (GARCH) process to improve overall performance. Then the conditional covariance obtained through dynamic conditional cor...
Unstable transient response of gyroscopic systems with stable eigenvalues
Giannini, O.
2016-06-01
Gyroscopic conservative dynamical systems may exhibit flutter instability that leads to a pair of complex conjugate eigenvalues, one of which has a positive real part and thus leads to a divergent free response of the system. When dealing with non-conservative systems, the pitch fork bifurcation shifts toward the negative real part of the root locus, presenting a pair of eigenvalues with equal imaginary parts, while the real parts may or may not be negative. Several works study the stability of these systems for relevant engineering applications such as the flutter in airplane wings or suspended bridges, brake squeal, etc. and a common approach to detect the stability is the complex eigenvalue analysis that considers systems with all negative real part eigenvalues as stable systems. This paper studies analytically and numerically the cases where the free response of these systems exhibits a transient divergent time history even if all the eigenvalues have negative real part thus usually considered as stable, and relates such a behaviour to the non orthogonality of the eigenvectors. Finally, a numerical method to evaluate the presence of such instability is proposed.
Uncertainty of angular displacement measurement with a MEMS gyroscope integrated in a smartphone
de Campos Porath, Maurício; Dolci, Ricardo
2015-10-01
Low-cost inertial sensors have recently gained popularity and are now widely used in electronic devices such as smartphones and tablets. In this paper we present the results of a set of experiments aiming to assess the angular displacement measurement errors of a gyroscope integrated in a smartphone of a recent model. The goal is to verify whether these sensors could substitute dedicated electronic inclinometers for the measurement of angular displacement. We estimated a maximum error of 0.3° (sum of expanded uncertainty and maximum absolute bias) for the roll and pitch axes, for a measurement time without referencing up to 1 h.
Space radiation effect on fibre optical gyroscope control circuit and compensation algorithm
Zhang Chun-Xi; Tian Hai-Ting; Li Min; Jin Jing; Song Ning-Fang
2008-01-01
The process of a γ-irradiation experiment of fibre optical gyroscope (FOG) control circuit was described,in which it is demonstrated that the FOG control circuit,except for D/A converter,could endure the dose of 10krad with the protection of cabin material.The distortion and drift in D/A converter due to radiation,which affect the performance of FOG seriously,was indicated based on the elemental analysis.Finally,a compensation network based on adaptive neuro-fuzzy inference system is proposed and its function is verified by simulation.
Yang, Xiao-Dong; An, Hua-Zhen; Qian, Ying-Jing; Zhang, Wei; Melnik, Roderick V. N.
2016-12-01
The synchronous in-unison motions in vibrational mechanics and the non-synchronous out-of-unison motions are the most frequently found periodic motions in every fields of science and everywhere in the universe. In contrast to the in-unison normal modes, the out-of-unison complex modes feature a π/2 phase difference. By the complex mode analysis we classify the out-of-unison planar motion into two types, gyroscopic motions and elliptic motions. It is found that the gyroscopic and elliptic motions have different characteristics for a two degree-of-freedom (2DOF) system. The gyroscopic motion involves two distinct frequencies with, respectively, two corresponding complex modes. However, the elliptic motion the nonlinear non-gyroscopic 2DOF system with repeated frequencies involves only single frequency with corresponding two complex modes. The study of the differences and similarities of the gyroscopic and elliptic modes sheds new light on the in-depth mechanism of the planar motions in the universe and the man-made engineering systems.
Subjective Relational Experiences and Employee Innovative Behaviors in the Workplace
Vinarski-Peretz, Hedva; Binyamin, Galy; Carmeli, Abraham
2011-01-01
This paper presents two studies that explore the implications of subjective relational experiences (positive regard, mutuality and vitality) on employee engagement in innovative behaviors at work. Data collected at two points in time were used to test two mediation models that link subjective relational experiences and innovative behaviors. The…
Subjective Relational Experiences and Employee Innovative Behaviors in the Workplace
Vinarski-Peretz, Hedva; Binyamin, Galy; Carmeli, Abraham
2011-01-01
This paper presents two studies that explore the implications of subjective relational experiences (positive regard, mutuality and vitality) on employee engagement in innovative behaviors at work. Data collected at two points in time were used to test two mediation models that link subjective relational experiences and innovative behaviors. The…
Does the Saenger gedanken experiment advance Einstein's special relativity theory?
Schmidt, Werner
1987-12-01
The basics of Einstein's theory of special relativity are reviewed, and the impact of the Saenger gedanken experiment on the theory is considered. The application of this experiment to the clock paradox is stressed. The relevance of special relativity on some current astrophysical problems is addressed.
A Micro-Machined Gyroscope for Rotating Aircraft
Yan, Qingwen; Zhang, Fuxue; Zhang, Wei
2012-01-01
In this paper we present recent work on the design, fabrication by silicon micromachining, and packaging of a new gyroscope for stabilizing the autopilot of rotating aircraft. It operates based on oscillation of the silicon pendulum between two torsion girders for detecting the Coriolis force. The oscillation of the pendulum is initiated by the rolling and deflecting motion of the rotating carrier. Therefore, the frequency and amplitude of the oscillation are proportional to the rolling frequency and deflecting angular rate of the rotating carrier, and are measured by the sensing electrodes. A modulated pulse with constant amplitude and unequal width is obtained by a linearizing process of the gyroscope output signal and used to control the deflection of the rotating aircraft. Experimental results show that the gyroscope has a resolution of 0.008 °/s and a bias of 56.18 °/h. PMID:23012572
Hybrid fiber resonator employing LRSPP waveguide coupler for gyroscope
Qian, Guang; Fu, Xing-Chang; Zhang, Li-Jiang; Tang, Jie; Liu, Yi-Ran; Zhang, Xiao-Yang; Zhang, Tong
2017-01-01
Polarization error and temperature noise are two main limits to the performance of resonant fiber optic gyroscope (RFOG). To overcome these limits, we demonstrated a hybrid resonator consisting of a polymer-based long-range surface plasmon polariton (LRSPP) waveguide coupler and a silica fiber. Single-polarization property of LRSPP waveguide and the offsetting of the opposite thermo-optical characteristics between the polymer-based LRSPP waveguide and the silica fiber can effectively inhibit both the polarization error and the temperature noise of RFOG. The measured resonance spectrum of the hybrid resonator shows the absence of polarization noise. The temperature dependence of wavelength shift (TDWS) of resonator dropped to about 2 pm/°C, or even to 0 pm/°C with optimal structure, which dramatically improves the temperature stability of gyroscope system. In addition, the hybrid resonator also shows tremendous application potential in rate-grade and tactical-grade gyroscopes. PMID:28117412
Optical gyroscope with controllable dispersion in four wave mixing regime.
Mikhailov, Eugeniy; Wolfe, Owen; Du, Shuangli; Rochester, Simon; Budker, Dmitry; Novikova, Irina
2016-05-01
We present our work towards realization of the fast-light gyroscope prototype, in which the sensitivity enhancement (compared to a regular laser gyroscopes) is achieved by adjusting the intra-cavity dispersion. We discuss schematics and underlying nonlinear effects leading to the negative dispersion in Rb vapor: level structure, optically addressed transitions, and configuration of the resonant cavity. We investigate dependence of the pulling factor (i.e., the ratio of the lasing frequency shift with the change of the cavity length to the equivalent resonance frequency shift in the empty cavity) on pump lasers detunings, power, and density of the atomic vapor. The observation of the pulling factor exceeding unity implies the gyroscope sensitivity improvement over the regular system This work is supported by Naval Air Warfare Center STTR program N68335-11-C-0428.
Thermal and Quantum Mechanical Noise of a Superfluid Gyroscope
Chui, Talso; Penanen, Konstantin
2004-01-01
A potential application of a superfluid gyroscope is for real-time measurements of the small variations in the rotational speed of the Earth, the Moon, and Mars. Such rotational jitter, if not measured and corrected for, will be a limiting factor on the resolution potential of a GPS system. This limitation will prevent many automation concepts in navigation, construction, and biomedical examination from being realized. We present the calculation of thermal and quantum-mechanical phase noise across the Josephson junction of a superfluid gyroscope. This allows us to derive the fundamental limits on the performance of a superfluid gyroscope. We show that the fundamental limit on real-time GPS due to rotational jitter can be reduced to well below 1 millimeter/day. Other limitations and their potential mitigation will also be discussed.
Scale factor characteristics of laser gyroscopes of different sizes
Fan, Zhenfang; Lu, Guangfeng; Hu, Shomin; Wang, Zhiguo; Luo, Hui
2016-04-01
The scale factor correction characteristics of two ring laser gyroscopes of different sizes are investigated systematically in this paper. The variation in the scale factor can reach 144 or 70 ppm for square gyroscopes with arm lengths of 8.4 cm or 15.6 cm, respectively, during frequency tuning. A dip in the scale factor is observed at the line center of the gain characteristic for both gyroscope sizes. When a different longitudinal mode is excited, the scale factor behavior remains the same, but the scale factor values differ slightly from those derived from geometric prediction. The scale factor tends to decrease with increasing discharge current, but the sensitivity of the scale factor to variations in the excitation decreases with increasing discharge current.
Periodic Error Compensation for Quartz MEMS Gyroscope Drift of INS
Xu Jianmao; Zhang Haipeng; Sun Junzhong
2007-01-01
In order to improve the navigation accuracy of an inertial navigation system (INS), composed of quartz gyroscopes, the existing real-time compensation methods for periodic errors in quartz gyroscope drift and the periodic error term relationship between sampled original data and smoothed data are reviewed. On the base of the results, a new compensation method called using former period characteristics to compensate latter smoothness data (UFCL for short) method is proposed considering the INS working characteristics. This new method uses the original data without smoothing to work out an error conversion formula at the INS initial alignment time and then compensate the smoothed data errors by way of the formula at the navigation time. Both theoretical analysis and experimental results demonstrate that this method is able to cut down on computational time and raise the accuracy which makes it a better real-time compensation approach for periodic error terms of quartz micro electronic mechanical system (MEMS) gyroscope's zero drift.
A Micro-Machined Gyroscope for Rotating Aircraft
Fuxue Zhang
2012-07-01
Full Text Available In this paper we present recent work on the design, fabrication by silicon micromachining, and packaging of a new gyroscope for stabilizing the autopilot of rotating aircraft. It operates based on oscillation of the silicon pendulum between two torsion girders for detecting the Coriolis force. The oscillation of the pendulum is initiated by the rolling and deflecting motion of the rotating carrier. Therefore, the frequency and amplitude of the oscillation are proportional to the rolling frequency and deflecting angular rate of the rotating carrier, and are measured by the sensing electrodes. A modulated pulse with constant amplitude and unequal width is obtained by a linearizing process of the gyroscope output signal and used to control the deflection of the rotating aircraft. Experimental results show that the gyroscope has a resolution of 0.008 °/s and a bias of 56.18 °/h.
Miniature, Variable-Speed Control Moment Gyroscope
Bilski, Steve; Kline-Schoder, Robert; Sorensen, Paul
2011-01-01
The Miniature Variable-Speed Control Moment Gyroscope (MVS-CMG) was designed for small satellites (mass from less than 1 kg up to 500 kg). Currently available CMGs are too large and heavy, and available miniature CMGs do not provide sufficient control authority for use on practical satellites. This primarily results from the need to greatly increase the speed of rotation of the flywheel in order to reduce the flywheel size and mass. This goal was achieved by making use of a proprietary, space-qualified, high-speed (100,000 rpm) motor technology to spin the flywheel at a speed ten times faster than other known miniature CMGs under development. NASA is supporting innovations in propulsion, power, and guidance and navigation systems for low-cost small spacecraft. One of the key enabling technologies is attitude control mechanisms. CMGs are particularly attractive for spacecraft attitude control since they can achieve higher torques with lower mass and power than reaction wheels, and they provide continuous torque capability that enables precision pointing (in contrast to on-off thruster control). The aim of this work was to develop a miniature, variable-speed CMG that is sized for use on small satellites. To achieve improved agility, these spacecraft must be able to slew at high rate, which requires attitude control actuators that can apply torques on the order of 5 N-m. The MVS-CMG is specifically designed to achieve a high-torque output with a minimum flywheel and system mass. The flywheel can be run over a wide range of speeds, which is important to help reduce/eliminate potential gimbal lock, and can be used to optimize the operational envelope of the CMG.
LeMoyne, Robert; Mastroianni, Timothy
2016-08-01
Natural gait consists of synchronous and rhythmic patterns for both the lower and upper limb. People with hemiplegia can experience reduced arm swing, which can negatively impact the quality of gait. Wearable and wireless sensors, such as through a smartphone, have demonstrated the ability to quantify various features of gait. With a software application the smartphone (iPhone) can function as a wireless gyroscope platform capable of conveying a gyroscope signal recording as an email attachment by wireless connectivity to the Internet. The gyroscope signal recordings of the affected hemiplegic arm with reduced arm swing arm and the unaffected arm are post-processed into a feature set for machine learning. Using a multilayer perceptron neural network a considerable degree of classification accuracy is attained to distinguish between the affected hemiplegic arm with reduced arm swing arm and the unaffected arm.
Microfibrous metallic cloth for acoustic isolation of a MEMS gyroscope
Dean, Robert; Burch, Nesha; Black, Meagan; Beal, Aubrey; Flowers, George
2011-04-01
The response of a MEMS device that is exposed to a harsh environment may range from an increased noise floor to a completely erroneous output to temporary or even permanent device failure. One such harsh environment is high power acoustic energy possessing high frequency components. This type of environment sometimes occurs in small aerospace vehicles. In this type of operating environment, high frequency acoustic energy can be transferred to a MEMS gyroscope die through the device packaging. If the acoustic noise possesses a sufficiently strong component at the resonant frequency of the gyroscope, it will overexcite the motion of the proof mass, resulting in the deleterious effect of corrupted angular rate measurement. Therefore if the device or system packaging can be improved to sufficiently isolate the gyroscope die from environmental acoustic energy, the sensor may find new applications in this type of harsh environment. This research effort explored the use of microfibrous metallic cloth for isolating the gyroscope die from environmental acoustic excitation. Microfibrous cloth is a composite of fused, intermingled metal fibers and has a variety of typical uses involving chemical processing applications and filtering. Specifically, this research consisted of experimental evaluations of multiple layers of packed microfibrous cloth composed of sintered nickel material. The packed cloth was used to provide acoustic isolation for a test MEMS gyroscope, the Analog Devices ADXRS300. The results of this investigation revealed that the intermingling of the various fibers of the metallic cloth provided a significant contact area between the fiber strands and voids, which enhanced the acoustic damping of the material. As a result, the nickel cloth was discovered to be an effective acoustic isolation material for this particular MEMS gyroscope.
A New MEMS Gyroscope Used for Single-Channel Damping.
Zhang, Zengping; Zhang, Wei; Zhang, Fuxue; Wang, Biao
2015-04-30
The silicon micromechanical gyroscope, which will be introduced in this paper, represents a novel MEMS gyroscope concept. It is used for the damping of a single-channel control system of rotating aircraft. It differs from common MEMS gyroscopes in that does not have a drive structure, itself, and only has a sense structure. It is installed on a rotating aircraft, and utilizes the aircraft spin to make its sensing element obtain angular momentum. When the aircraft is subjected to an angular rotation, a periodic Coriolis force is induced in the direction orthogonal to both the angular momentum and the angular velocity input axis. This novel MEMS gyroscope can thus sense angular velocity inputs. The output sensing signal is exactly an amplitude-modulation signal. Its envelope is proportional to the input angular velocity, and the carrier frequency corresponds to the spin frequency of the rotating aircraft, so the MEMS gyroscope can not only sense the transverse angular rotation of an aircraft, but also automatically change the carrier frequency over the change of spin frequency, making it very suitable for the damping of a single-channel control system of a rotating aircraft. In this paper, the motion equation of the MEMS gyroscope has been derived. Then, an analysis has been carried to solve the motion equation and dynamic parameters. Finally, an experimental validation has been done based on a precision three axis rate table. The correlation coefficients between the tested data and the theoretical values are 0.9969, 0.9872 and 0.9842, respectively. These results demonstrate that both the design and sensing mechanism are correct.
A New MEMS Gyroscope Used for Single-Channel Damping
Zengping Zhang
2015-04-01
Full Text Available The silicon micromechanical gyroscope, which will be introduced in this paper, represents a novel MEMS gyroscope concept. It is used for the damping of a single-channel control system of rotating aircraft. It differs from common MEMS gyroscopes in that does not have a drive structure, itself, and only has a sense structure. It is installed on a rotating aircraft, and utilizes the aircraft spin to make its sensing element obtain angular momentum. When the aircraft is subjected to an angular rotation, a periodic Coriolis force is induced in the direction orthogonal to both the angular momentum and the angular velocity input axis. This novel MEMS gyroscope can thus sense angular velocity inputs. The output sensing signal is exactly an amplitude-modulation signal. Its envelope is proportional to the input angular velocity, and the carrier frequency corresponds to the spin frequency of the rotating aircraft, so the MEMS gyroscope can not only sense the transverse angular rotation of an aircraft, but also automatically change the carrier frequency over the change of spin frequency, making it very suitable for the damping of a single-channel control system of a rotating aircraft. In this paper, the motion equation of the MEMS gyroscope has been derived. Then, an analysis has been carried to solve the motion equation and dynamic parameters. Finally, an experimental validation has been done based on a precision three axis rate table. The correlation coefficients between the tested data and the theoretical values are 0.9969, 0.9872 and 0.9842, respectively. These results demonstrate that both the design and sensing mechanism are correct.
Zuoming, Sun; Shuhua, Wang; Junwei, Li; Yazhou, Zhang; Dapeng, Chen
2016-12-01
Bias thermal stability of a fiber-optic gyroscope using polarization-maintaining photonic crystal (PM-PCF) was studied. The thermal sensitivity of birefringence in PM-PCF and polarization cross talking in fiber coil was measured. Using an OCDP method, the polarization cross talking causing phase error of the fiber-optic gyroscope (FOG) was analyzed. The contrast experiment result of the FOGs with the PM-PCF coil and PMF coil showed that using PM-PCF instead of PMF can improve the FOG's bias thermal stability by about 50 %.
Vorticity, gyroscopic precession, and spin-curvature force
Liang, Wei Chieh; Lee, Si Chen
2013-02-01
In investigating the relationship between vorticity and gyroscopic precession, we calculate the vorticity vector in Godel, Kerr, Lewis, Schwarzschild, and Minkowski metrics and find that the vorticity vector of the specific observers is the angular velocity of the gyroscopic precession. Furthermore, when space-time torsion is included, the vorticity and spin-curvature force change sign. This result is very similar to the behavior of the positive and negative helicities of quantum spin in the Stern-Gerlach force. It implies that the inclusion of torsion will lead to an analogous property of quantum spin even in classical treatment.
Studying rotational dynamics with a smartphone—accelerometer versus gyroscope
Braskén, Mats; Pörn, Ray
2017-07-01
The wide-spread availability of smartphones makes them a valuable addition to the measurement equipment of both the physics classroom and the instructional physics laboratory, encouraging an active interaction between measurements and modeling activities. Two useful sensors, available in most modern smartphones and tablets, are the 3-axis acceleration sensor and the 3-axis gyroscope. We explore the strengths and weaknesses of each type of sensor and use them to study the rotational dynamics of objects rotating about a fixed axis. Care has to be taken when interpreting acceleration sensor data, and in some cases the gyroscope will allow for rotational measurements not easily replicated using the acceleration sensor.
Bifurcations of Eigenvalues of Gyroscopic Systems with Parameters Near Stability Boundaries
Seyranian, Alexander P.; Kliem, Wolfhard
1999-01-01
. It is shown that the bifurcation (splitting) of double eigenvalues is closely related to the stability, flutter and divergence boundaries in the parameter space. Normal vectors to these boundaries are derived using only information at a boundary point: eigenvalues, eigenvectors and generalized eigenvectors......The paper deals with stability problems of linear gyroscopic systems with finite or infinite degrees of freedom, where the system matrices or operators depend smoothly on several real parameters. Explicit formulae for the behavior of eigenvalues under a change of parameters are obtained...
Droogendijk, H; Brookhuis, R A; de Boer, M J; Sanders, R G P; Krijnen, G J M
2014-10-06
Flies use so-called halteres to sense body rotation based on Coriolis forces for supporting equilibrium reflexes. Inspired by these halteres, a biomimetic gimbal-suspended gyroscope has been developed using microelectromechanical systems (MEMS) technology. Design rules for this type of gyroscope are derived, in which the haltere-inspired MEMS gyroscope is geared towards a large measurement bandwidth and a fast response, rather than towards a high responsivity. Measurements for the biomimetic gyroscope indicate a (drive mode) resonance frequency of about 550 Hz and a damping ratio of 0.9. Further, the theoretical performance of the fly's gyroscopic system and the developed MEMS haltere-based gyroscope is assessed and the potential of this MEMS gyroscope is discussed.
Construction of Lyapunov Function for Dissipative Gyroscopic System
XU Wei; YUAN Bo; AO Ping
2011-01-01
@@ We introduce a force decomposition to construct a potential function in deterministic dynamics described by ordinary differential equations in the context of dissipative gyroscopic systems.Such a potential function serves as the corresponding Lyapunov function for the dynamics,hence it gives both quantitative and qualitative descriptions for stability of motion.As an example we apply our force decomposition to a four-dimensional dissipative gyroscopic system.We explicitly obtain the potential function for all parameter regimes in the linear limit,including those regimes where the Lyapunov function was previously believed not to exist.%We introduce a force decomposition to construct a potential function in deterministic dynamics described by ordinary differential equations in the context of dissipative gyroscopic systems. Such a potential function serves as the corresponding Lyapunov function for the dynamics, hence it gives both quantitative and qualitative descriptions for stability of motion. As an example we apply our force decomposition to a four-dimensional dissipative gyroscopic system. We explicitly obtain the potential function for all parameter regimes in the linear limit, including those regimes where the Lyapunov function was previously believed not to exist.
Understanding Organizational Culture and Communication through a Gyroscope Metaphor
Bisel, Ryan S.; Messersmith, Amber S.; Keyton, Joann
2010-01-01
To fill a critical void in organizational culture pedagogy, the authors present an instructional system that employs the metaphor of a gyroscope to help students understand implicit assumptions in culture research. Working from Martin's nexus approach to organizational culture and Fairhurst and Putnam's tripartite theory of organizational…
Laser gyroscopes. Citations from the NTIS data base
Young, C. G.
1980-05-01
Laser inertial rotation sensors are discussed in approximately 27 citations. Ring lasers, fiber optic ring lasers, and laser or optical gyroscopes are discussed. Technical problems, such as mode coupling and competition, stray scattering, error sources, and analyses, are treated. The design, engineering, construction, and performance of operational hardware are described.
Fiber gyroscope with a double sensitivity employing a polarization splitter.
Zhou, Kejiang; Pan, Shuming; Liu, Shujun; Hu, Keke
2013-04-15
An effective method for enhancing the sensitivity of interferometric fiber-optic gyroscope (IFOG) is presented. Light waves propagate twice along the same sensing coil made of polarization-maintaining fiber in different polarization states by inducing a fiber polarization splitter/combining in the IFOG. Preliminary performance data of a gyro prototype exhibits 0.006°/h bias stability.
Understanding Organizational Culture and Communication through a Gyroscope Metaphor
Bisel, Ryan S.; Messersmith, Amber S.; Keyton, Joann
2010-01-01
To fill a critical void in organizational culture pedagogy, the authors present an instructional system that employs the metaphor of a gyroscope to help students understand implicit assumptions in culture research. Working from Martin's nexus approach to organizational culture and Fairhurst and Putnam's tripartite theory of organizational…
General problems of dynamics and control of vibratory gyroscopes
Shatalov, MY
2008-05-01
Full Text Available A general model of operation of vibratory gyroscopes, which is applicable to a broad class of instruments, including cylindrical, disc and micro-machined gyros, is formulated on the basis of analysis of dynamics and control of a hemispherical...
Comments on Stability Properties of Conservative Gyroscopic Systems
Lancaster, Peter; Kliem, Wolfhard
1999-01-01
A conjecture of Renshaw and Mote concerning gyroscopic systems with parameters predicts the eigenvalue locus in the neighborhood of a double-zero eigenvalue. In the present paper, this conjecture is reformulated in the language of generalized eigenvectors, angular splitting, and analytic behavior...
14 CFR 23.371 - Gyroscopic and aerodynamic loads.
2010-01-01
... Flight Loads § 23.371 Gyroscopic and aerodynamic loads. (a) Each engine mount and its supporting... engine mount and its supporting structure must meet the requirements of paragraph (a) of this section and.... (c) For airplanes certificated in the commuter category, each engine mount and its...
Coupled electromechanical model of an imperfect piezoelectric vibrating cylinder gyroscope
Loveday, PW
1996-01-01
Full Text Available which is closed at one end with discrete piezoceramic actuation and sensing elements bonded close to the open end. The operation of the gyroscope and the effect of imperfections are briefly described. The model allows direct comparison with experimental...
Noise Reduction for a MEMS-Gyroscope-Based Head Mouse.
Du, Jiaying; Gerdtman, Christer; Lindén, Maria
2015-01-01
In this paper, four different signal processing algorithms which can be applied to reduce the noise from a MEMS-gyroscope-based computer head mouse are presented. MEMS-gyroscopes are small, light, cheap and widely used in many electrical products. MultiPos, a MEMS-gyroscope-based computer head mouse system was designed for persons with movement disorders. Noise such as physiological tremor and electrical noise is a common problem for the MultiPos system. In this study four different signal processing algorithms were applied and evaluated by simulation in MATLAB and implementation in a dsPIC, with aim to minimize the noise in MultiPos. The algorithms were low-pass filter, Least Mean Square (LMS) algorithm, Kalman filter and Weighted Fourier Linear Combiner (WFLC) algorithm. Comparisons and system tests show that these signal processing algorithms can be used to improve the MultiPos system. The WFLC algorithm was found the best method for noise reduction in the application of a MEMS-gyroscope-based head mouse.
Introducing Gyroscopes Quantitatively without Putting Students into a Spin
McGlynn, Enda
2007-01-01
The uniform precession of a simple form of gyroscope is analysed via a direct application of Newton's laws, using only concepts generally taught to physics and engineering students in the first two years of an undergraduate programme, with an emphasis on understanding the forces and torques acting on the system. This type of approach, in the…
Measuring Experiences of Interest-Related Pursuits in Connected Learning
Maul, Andrew; Penuel, William R.; Dadey, Nathan; Gallagher, Lawrence P.; Podkul, Timothy; Price, Emily
2017-01-01
This paper describes an effort to develop a survey instrument capable of measuring important aspects of adolescents' experiences of interest-related pursuits that are supported by technology. The measure focuses on youths' experiences of "connected learning" (Ito et al. in Connected learning: an agenda for research and design. Digital…
Does the Fizeau Experiment Really Test Special Relativity?
Clement, Gerard
1980-01-01
The motivation and interpretation of the Fizeau experiment are reviewed, and its status as a test of special relativity is discussed. It is shown, with the aid of a simplified, purely mechanical model of the propagation of light in matter, that the experiment actually cannot discriminate between Galilean and relativistic kinematics. (Author/SK)
Experiments in Special Relativity Using Compton Scattering of Gamma Rays.
Egelstaff, P. A.; And Others
1981-01-01
Some simple undergraduate laboratory experiments are described, which verify the energy-momentum relationship of special relativity. These experiments have been designed either to be used as classroom demonstrations or to be carried out by second-year students. (Author/JN)
Robust MEMS gyroscope for oil and gas exploration
Lin, David; Miller, Todd
2014-06-01
To satisfy the performance and reliability requirement of a MEMS based harsh environment sensor, the sensor development needs to depart from the classic method of single-discipline technology improvement. In this paper, the authors will describe a Microsystem-based design methodology which considers simultaneous multiple technology domain interaction and achieves performance optimization at the system level to address the harsh environment sensing challenge. This is demonstrated through specific examples of investigating a robust MEMS gyroscope suitable for high temperature and high vibration environments such as down-hole drilling for Oil and Gas applications. In particular, the different mechanisms of temperature-induced errors in MEMS gyroscope are discussed. The error sources include both the direct impact of the gyroscope dynamics by temperature and the indirect perturbation by temperature-induced package stress. For vibration and shock induced failure, the error contributions from the low frequency and high frequency contents are discussed. Different transducer designs with equivalent rate sensitivity can vary with several orders of magnitude in terms of the susceptibility to mechanical vibration. Also shown are the complex interactions among the gyroscopic transducer, packaging and the control electronics, resulting from these temperature and vibration error sources. The microsystem-based design methodology is able to capture such complex interactions and improve the gyroscope temperature and vibration performance. In contrast to other efforts in harsh environment sensing which focus on specific technology domains, the authors strive to demonstrate the need and advantage of addressing MEMS performance and reliability in harsh environment from a microsystem perspective.
SCALE FACTOR DETERMINATION METHOD OF ELECTRO-OPTICAL MODULATOR IN FIBER-OPTIC GYROSCOPE
A. S. Aleynik
2016-05-01
Full Text Available Subject of Research. We propose a method for dynamic measurement of half-wave voltage of electro-optic modulator as part of a fiber optic gyroscope. Excluding the impact of the angular acceleration on measurement of the electro-optical coefficient is achieved through the use of homodyne demodulation method that allows a division of the Sagnac phase shift signal and an auxiliary signal for measuring the electro-optical coefficient in the frequency domain. Method. The method essence reduces to decomposition of step of digital serrodyne modulation in two parts with equal duration. The first part is used for quadrature modulation signals. The second part comprises samples of the auxiliary signal used to determine the value of the scale factor of the modulator. Modeling is done in standalone model, and as part of a general model of the gyroscope. The applicability of the proposed method is investigated as well as its qualitative and quantitative characteristics: absolute and relative accuracy of the electro-optic coefficient, the stability of the method to the effects of angular velocities and accelerations, method resistance to noise in actual devices. Main Results. The simulation has showed the ability to measure angular velocity changing under the influence of angular acceleration, acting on the device, and simultaneous measurement of electro-optical coefficient of the phase modulator without interference between these processes. Practical Relevance. Featured in the paper the ability to eliminate the influence of the angular acceleration on the measurement accuracy of the electro-optical coefficient of the phase modulator will allow implementing accurate measurement algorithms for fiber optic gyroscopes resistant to a significant acceleration in real devices.
HUANG Xiao-gang; CHEN Wen-yuan; LIU Wu; ZHANG Wei-ping; WU Xiao-sheng
2007-01-01
In the novel prototype of micro-gyroscope structure, the new configured capacitance sensing scheme for the micro gyroscope was analyzed and the virtual instrument based detection scheme was implemented. The digital lock-in amplifier was employed in the capacitance detection to restrain the noise interference. The capacitance analysis shows that 1 fF capacitance variation corresponds to 0.1 degree of the turn angle. The differential capacitance bridge and the charge integral amplifier were used as the front signal input interface. In the implementation of digital lock-in amplifier, a new routine which warranted the exactly matching of the reference phase to signal phase was proposed. The result of the experiment shows that digital lock-in amplifier can greatly eliminate the noise in the output signal. The non linearity of the turn angle output is 2.3 % and the minimum resolution of turn angle is 0.04 degrees. The application of the software demodulation in the signal detection of micro-electro-mechanical-system (MEMS) device is a new attempt, and it shows the prospective for a high-performance application.
Wang, Kai; Fan, Zhenfang; Wang, Dongya; Wang, Yanyan; Pan, Yao; Qu, Tianliang; Xu, Guangming
2016-10-01
The existence of mode deflection angle in the cylindrical resonator gyroscope (CRG) leads to the signal drift on the detecting nodes of the gyro vibration and significantly decreases the performance of the CRG. Measuring the mode deflection angle efficiently is the foundation of tuning for the imperfect cylindrical shell resonator. In this paper, an optical method based on the measuring gyroscopic resonator's vibration amplitude with the laser Doppler vibrometer and an electrical method based on measuring the output voltage of the electrodes on the resonator are both presented to measure the mode deflection angle. Comparative experiments were implemented to verify the methodology and the results show that both of the two methods could recognize the mode deflection angle efficiently. The precision of the optical method relies on the number and position of testing points distributed on the resonator. The electrical method with simple circuit shows high accuracy of measuring in a less time compared to the optical method and its error source arises from the influence of circuit noise as well as the inconsistent distribution of the piezoelectric electrodes.
Analysis of dead zone sources in a closed-loop fiber optic gyroscope.
Chong, Kyoung-Ho; Choi, Woo-Seok; Chong, Kil-To
2016-01-01
Analysis of the dead zone is among the intensive studies in a closed-loop fiber optic gyroscope. In a dead zone, a gyroscope cannot detect any rotation and produces a zero bias. In this study, an analysis of dead zone sources is performed in simulation and experiments. In general, the problem is mainly due to electrical cross coupling and phase modulation drift. Electrical cross coupling is caused by interference between modulation voltage and the photodetector. The cross-coupled signal produces spurious gyro bias and leads to a dead zone if it is larger than the input rate. Phase modulation drift as another dead zone source is due to the electrode contamination, the piezoelectric effect of the LiNbO3 substrate, or to organic fouling. This modulation drift lasts for a short or long period of time like a lead-lag filter response and produces gyro bias error, noise spikes, or dead zone. For a more detailed analysis, the cross-coupling effect and modulation phase drift are modeled as a filter and are simulated in both the open-loop and closed-loop modes. The sources of dead zone are more clearly analyzed in the simulation and experimental results.
Online self-compensation for enhanced the scale factor stability of a micromachined gyroscope
Zhou Bin; Zhang Rong; Chen Zhiyong [Department of Precision Instrument, Tsinghua University, Beijing, 100084 (China)], E-mail: zhoubin98@tsinghua.org.cn
2009-09-01
In this paper, an online self-compensation control scheme for micromachined gyroscope has been presented to eliminate the scale factor drift due to temperature influence. Firstly, the error sources of scale factor have been analyzed. According the analysis results, a novel control scheme which contains three loops has been proposed: a phase-locked loop of driving mode is to drive the proof mass oscillation in its' resonant frequency, an AGC loop of driving mode is to keep a constant value of the drive amplitude, an additional scale factor error online detection and cancellation loop is to keep the scale factor stable. A digital hardware prototype has been implemented to perform the precision loop control and self-compensation loop. Scale factor of the gyroscope has been measured in a temperature-controlled turntable. Experiment results show that the scale factor drift is -3.5% to 5.2% over the temperature range of -45 deg. C to +80 deg. C without the self-compensation loop, while the scale factor drift decrease to -0.009% to 0.15% after the self-compensation loop is applied.
Amel'kin, N. I.
2010-01-01
Steady motions of a rigid body with a control momentum gyroscope are studied versus the gimbal axis direction relative to the body and the magnitude of the system angular momentum. The study is based on a formula that gives a parametric representation of the set of the system steady motions in terms
Teaching Quantum Mechanical Commutation Relations via an Optical Experiment
Billur, A Alper; Bursal, Murat
2015-01-01
The quantum mechanical commutation relations, which are directly related to the Heisenberg uncertainty principle, have a crucial importance for understanding the quantum mechanics of students. During undergraduate level courses, the operator formalisms are generally given theoretically and it is documented that these abstract formalisms are usually misunderstood by the students. Based on the idea that quantum mechanical phenomena can be investigated via geometric optical tools, this study aims to introduce an experiment, where the quantum mechanical commutation relations are represented in a concrete way to provide students an easy and permanent learning. The experimental tools are chosen to be easily accessible and economic. The experiment introduced in this paper can be done with students or used as a demonstrative experiment in laboratory based or theory based courses requiring quantum physics content; particularly in physics, physics education and science education programs.
Wang, Yang-Yang; Zhang, Tong
2014-01-01
Spontaneous emission noise is an important limit to the performance of active plasmonic devices. Here, we investigate the spontaneous emission noise in the long-range surface plasmon-polariton waveguide based optical gyroscope. A theoretical model of the sensitivity is established to study the incoherent multi-beam interference of spontaneous emission in the gyroscope. Numerical results show that spontaneous emission produces a drift in the transmittance spectra and lowers the signal-to-noise-ratio of the gyroscope. It also strengthens the shot noise to be the main limit to the sensitivity of the gyroscope for high propagation loss. To reduce the negative effects of the spontaneous emission noise on the gyroscope, an external feedback loop is suggested to estimate the drift in the transmittance spectra and therefor enhance the sensitivity. Our work lays a foundation for the improvement of long-range surface plasmon-polariton gyroscope and paves the way to its practical application.
Robust adaptive control of MEMS triaxial gyroscope using fuzzy compensator.
Fei, Juntao; Zhou, Jian
2012-12-01
In this paper, a robust adaptive control strategy using a fuzzy compensator for MEMS triaxial gyroscope, which has system nonlinearities, including model uncertainties and external disturbances, is proposed. A fuzzy logic controller that could compensate for the model uncertainties and external disturbances is incorporated into the adaptive control scheme in the Lyapunov framework. The proposed adaptive fuzzy controller can guarantee the convergence and asymptotical stability of the closed-loop system. The proposed adaptive fuzzy control strategy does not depend on accurate mathematical models, which simplifies the design procedure. The innovative development of intelligent control methods incorporated with conventional control for the MEMS gyroscope is derived with the strict theoretical proof of the Lyapunov stability. Numerical simulations are investigated to verify the effectiveness of the proposed adaptive fuzzy control scheme and demonstrate the satisfactory tracking performance and robustness against model uncertainties and external disturbances compared with conventional adaptive control method.
Sliding mode control of a simulated MEMS gyroscope.
Batur, C; Sreeramreddy, T; Khasawneh, Q
2006-01-01
The microelectromechanical systems (MEMS) are penetrating more and more into measurement and control problems because of their small size, low cost, and low power consumption. The vibrating gyroscope is one of those MEMS devices that will have a significant impact on the stability control systems in transportation industry. This paper studies the design and control of a vibrating gyroscope. The device has been constructed in a Pro-E environment and its model has been simulated in the finite-element domain in order to approximate its dynamic characteristics with a lumped model. A model reference adaptive feedback controller and the sliding mode controller have been considered to guarantee the stability of the device. It is shown that the sliding mode controller of the vibrating proof mass results in a better estimate of the unknown angular velocity than that of the model reference adaptive feedback controller.
Coriolis effects are principally caused by gyroscopic angular acceleration.
Isu, N; Yanagihara, M; Mikuni, T; Koo, J
1994-07-01
A cause of nausea evoked by cross-coupled rotation (termed Coriolis stimulus) was determined. Subjects were provided with two types of cross-coupled rotations: neck-forward flexion (Neck Flx) and upper body-forward flexion (Body Flx) during horizontal whole body rotation at a constant angular velocity. These Coriolis stimuli were given alternatively in an experimental sequence, and the severity of the nausea they evoked was compared by the subjects. The results indicated that the same quality of nausea was evoked by a slightly higher angular velocity during Body Flx (100.5 degrees/s) than during Neck Flx (90 degrees/s). While Body Flx generated Coriolis linear acceleration several times larger than Neck Flx, both the stimuli generated a similar magnitude of gyroscopic angular acceleration in this condition. Therefore, it was inferred that the nausea evoked by a Coriolis stimulus is principally caused by gyroscopic angular acceleration.
A Multi-Fork Z-Axis Quartz Micromachined Gyroscope
Aiying Yang
2013-09-01
Full Text Available A novel multi-fork z-axis gyroscope is presented in this paper. Different from traditional quartz gyroscopes, the lateral electrodes of the sense beam can be arranged in simple patterns; as a result, the fabrication is simplified. High sensitivity is achieved by the multi-fork design. The working principles are introduced, while the finite element method (FEM is used to simulate the modal and sensitivity. A quartz fork is fabricated, and a prototype is assembled. Impedance testing shows that the drive frequency and sense frequency are similar to the simulations, and the quality factor is approximately 10,000 in air. The scale factor is measured to be 18.134 mV/(°/s and the nonlinearity is 0.40% in a full-scale input range of ±250 °/s.
Quantum Spin Gyroscope using NV centers in Diamond
Jaskula, Jean-Christophe; Saha, Kasturi; Ajoy, Ashok; Cappellaro, Paola
2015-05-01
Gyroscopes find wide applications in everyday life from navigation and inertial sensing to rotation sensors in hand-held devices and automobiles. Current devices, based on either atomic or solid-state systems, impose a choice between long-time stability and high sensitivity in a miniaturized system. We are building a solid-state spin gyroscope associated with the Nitrogen-Vacancy (NV) centers in diamond to overcome these constraints. More specifically, we will take advantage of the 14N nuclear spin coherence properties of NV centers and side-collection techniques to achieve high sensitivity of about 1 (mdeg s-1) /√{ (} Hz mm3) . Moreover, by exploiting the four classes of the NV axes, we will be able to determine axis of rotation as well as its rate.
Design and Optimization of Composite Gyroscope Momentum Wheel Rings
Bednarcyk, Brett A.; Arnold, Steven M.
2007-01-01
Stress analysis and preliminary design/optimization procedures are presented for gyroscope momentum wheel rings composed of metallic, metal matrix composite, and polymer matrix composite materials. The design of these components involves simultaneously minimizing both true part volume and mass, while maximizing angular momentum. The stress analysis results are combined with an anisotropic failure criterion to formulate a new sizing procedure that provides considerable insight into the design of gyroscope momentum wheel ring components. Results compare the performance of two optimized metallic designs, an optimized SiC/Ti composite design, and an optimized graphite/epoxy composite design. The graphite/epoxy design appears to be far superior to the competitors considered unless a much greater premium is placed on volume efficiency compared to mass efficiency.
A multi-fork z-axis quartz micromachined gyroscope.
Feng, Lihui; Zhao, Ke; Sun, Yunan; Cui, Jianmin; Cui, Fang; Yang, Aiying
2013-01-01
A novel multi-fork z-axis gyroscope is presented in this paper. Different from traditional quartz gyroscopes, the lateral electrodes of the sense beam can be arranged in simple patterns; as a result, the fabrication is simplified. High sensitivity is achieved by the multi-fork design. The working principles are introduced, while the finite element method (FEM) is used to simulate the modal and sensitivity. A quartz fork is fabricated, and a prototype is assembled. Impedance testing shows that the drive frequency and sense frequency are similar to the simulations, and the quality factor is approximately 10,000 in air. The scale factor is measured to be 18.134 mV/(°/s) and the nonlinearity is 0.40% in a full-scale input range of ±250 °/s.
Analytic solution of differential equation for gyroscope's motions
Tyurekhodjaev, Abibulla N.; Mamatova, Gulnar U.
2016-08-01
Problems of motion of a rigid body with a fixed point are one of the urgent problems in classical mechanics. A feature of this problem is that, despite the important results achieved by outstanding mathematicians in the last two centuries, there is still no complete solution. This paper obtains an analytical solution of the problem of motion of an axisymmetric rigid body with variable inertia moments in resistant environment described by the system of nonlinear differential equations of L. Euler, involving the partial discretization method for nonlinear differential equations, which was built by A. N. Tyurekhodjaev based on the theory of generalized functions. To such problems belong gyroscopic instruments, in particular, and especially gyroscopes.
A Low-Noise Readout Circuit for Gyroscopes
Guanshi Wang; Xiaowei Liu; Changchun Dong
2015-01-01
In order to suppress the noise of gyroscopes, the method based on lock⁃in amplifier and capacitor matching of the low⁃noise readout circuit is proposed. Firstly, the principle to suppress the noise by lock⁃in amplifier is analyzed, and the noise model of front end is proposed. Secondly, the noise optimization for the charge amplifier is presented according to the noise model of front end. Finally, a readout circuit is constructed by this approach. The measurement results show that the parasitic capacitance of front end is 18 pF, and the noise at resonant frequency ( 4 kHz) is 133 nV/Hz1/2 , and the overall bias stability is 30°/h, and the noise level is 0�003°/( s·Hz1/2 ) . The noise of the gyroscope with the low⁃noise readout by this method is suppressed effectively.
Student Teachers' Experiences of Relation Building in Teaching Practice
Nielsen, Anne Maj; Laursen, Per Fibæk
The study explores how 22 student teachers in a Danish college of education experience and interpret their own becoming a teacher and the implied attitudes to pupils. The student teachers attending mainstream teacher education and a course in mindful awareness and relational competencies have...... – to a larger extend than the mainstream educated student teachers - learned a reflexive attitude to their state of being in teaching practice and to their relational interaction with children in class....
Dynamics and bifurcations in a Dn-symmetric Hamiltonian network. Application to coupled gyroscopes
Buono, Pietro-Luciano; Chan, Bernard S.; Palacios, Antonio; In, Visarath
2015-01-01
The advent of novel engineered or smart materials, whose properties can be significantly altered in a controlled fashion by external stimuli, has stimulated the design and fabrication of smaller, faster, and more energy-efficient devices. As the need for even more powerful devices grows, networks have become popular alternatives to advance the fundamental limits of performance of individual units. In many cases, the collective rhythmic behavior of a network can be studied through the classical theory of nonlinear oscillators or through the more recent development of the coupled cell formalism. However, the current theory does not account yet for networks in which cells, or individual units, possess a Hamiltonian structure. One such example is a ring array of vibratory gyroscopes, where certain network topologies favor stable synchronized oscillations. Previous perturbation-based studies have shown that synchronized oscillations may, in principle, increase performance by reducing phase drift. The governing equations for larger array sizes are, however, not amenable to similar analysis. To circumvent this problem, the model equations are now reformulated in a Hamiltonian structure and the corresponding normal forms are derived. Through a normal form analysis, we investigate the effects of various coupling schemes and unravel the nature of the bifurcations that lead a ring of gyroscopes of any size into and out of synchronization. The Hamiltonian approach can, in principle, be readily extended to other symmetry-related systems.
Nitzan, Sarah H; Zega, Valentina; Li, Mo; Ahn, Chae H; Corigliano, Alberto; Kenny, Thomas W; Horsley, David A
2015-01-01
Parametric amplification, resulting from intentionally varying a parameter in a resonator at twice its resonant frequency, has been successfully employed to increase the sensitivity of many micro- and nano-scale sensors. Here, we introduce the concept of self-induced parametric amplification, which arises naturally from nonlinear elastic coupling between the degenerate vibration modes in a micromechanical disk-resonator, and is not externally applied. The device functions as a gyroscope wherein angular rotation is detected from Coriolis coupling of elastic vibration energy from a driven vibration mode into a second degenerate sensing mode. While nonlinear elasticity in silicon resonators is extremely weak, in this high quality-factor device, ppm-level nonlinear elastic effects result in an order-of-magnitude increase in the observed sensitivity to Coriolis force relative to linear theory. Perfect degeneracy of the primary and secondary vibration modes is achieved through electrostatic frequency tuning, which also enables the phase and frequency of the parametric coupling to be varied, and we show that the resulting phase and frequency dependence of the amplification follow the theory of parametric resonance. We expect that this phenomenon will be useful for both fundamental studies of dynamic systems with low dissipation and for increasing signal-to-noise ratio in practical applications such as gyroscopes.
Staab, Wieland; Hottowitz, Ralf; Sohns, Christian; Sohns, Jan Martin; Gilbert, Fabian; Menke, Jan; Niklas, Andree; Lotz, Joachim
2014-07-01
[Purpose] A wide variety of accelerometer tools are used to estimate human movement, but there are no adequate data relating to gait symmetry parameters in the context of knee osteoarthritis. This study's purpose was to evaluate a 3D-kinematic system using body-mounted sensors (gyroscopes and accelerometers) on the trunk and limbs. This is the first study to use spectral analysis for data post processing. [Subjects] Twelve patients with unilateral knee osteoarthritis (OA) (10 male) and seven age-matched controls (6 male) were studied. [Methods] Measurements with 3-D accelerometers and gyroscopes were compared to video analysis with marker positions tracked by a six-camera optoelectronic system (VICON 460, Oxford Metrics). Data were recorded using the 3D-kinematic system. [Results] The results of both gait analysis systems were significantly correlated. Five parameters were significantly different between the knee OA and control groups. To overcome time spent in expensive post-processing routines, spectral analysis was performed for fast differentiation between normal gait and pathological gait signals using the 3D-kinematic system. [Conclusions] The 3D-kinematic system is objective, inexpensive, accurate and portable, and allows long-term recordings in clinical, sport as well as ergonomic or functional capacity evaluation (FCE) settings. For fast post-processing, spectral analysis of the recorded data is recommended.
From the Foucault pendulum to the galactical gyroscope and LHC
Pardy, M
2006-01-01
We consider the Foucault pendulum, isosceles triangle pendulum and the general triangle pendulum rotating on the Earth. As an analogue, planet orbiting in the rotating galaxy is considered as the giant galactical gyroscope. The Lorentz and the Bargman-Michel-Telegdi equations are generalized for the rotating system. These equations are inevitable for LHC where orbital photons "feels" the Coriolis force caused by the rotation ofthe Earth.
Vibration Control of Tower Structure with Multiple Cardan Gyroscopes
Haoxiang He; Xin Xie; Wentao Wang
2017-01-01
Tower structure is sensitive to hurricane and earthquake, and it is easy to generate large deflection and dynamic response. The multiple cardan gyroscope has two rotational degrees of freedom, which can generate strong moments to constrain the two horizontal orthogonal deflections if the rotor operates in high speeds, so the structural dynamic responses can be decreased. Hence, the method of dynamic control of the tower structure under wind load and earthquake action is proposed by using the ...
Gyroscope Pivot Bearing Dimension and Surface Defect Detection
2011-01-01
Because of the perceived lack of systematic analysis in illumination system design processes and a lack of criteria for design methods in vision detection a method for the design of a task-oriented illumination system is proposed. After detecting the micro-defects of a gyroscope pivot bearing with a high curvature glabrous surface and analyzing the characteristics of the surface detection and reflection model, a complex illumination system with coaxial and ring lights is proposed. The illumin...
The role of entanglement in calibrating optical quantum gyroscopes
Kok, Pieter; Dunningham, Jacob; Ralph, Jason F.
2015-01-01
We consider the calibration of an optical quantum gyroscope by modeling two Sagnac interferometers, mounted approximately at right angles to each other. Reliable operation requires that we know the angle between the interferometers with high precision, and we show that a procedure akin to multi-position testing in inertial navigation systems can be generalized to the case of quantum interferometry. We find that while entanglement is a key resource within an individual Sagnac interferometer, i...
Optimized geometric configuration of active ring laser gyroscopes
Gormley, John; Salloum, Tony
2016-05-01
We present a thorough derivation of the Sagnac effect for a ring laser gyroscope of any arbitrary polygonal configuration. We determine optimized alternative geometric configurations for the mirrors. The simulations incur the implementation of a lasing medium with the standard square system, triangular, pentagonal, and oblongated square configuration (diamond). Simulations of possible new geometric configurations are considered, as well as the possibility of adjusting the concavity of the mirrors.
Design of integrated hybrid silicon waveguide optical gyroscope.
Srinivasan, Sudharsanan; Moreira, Renan; Blumenthal, Daniel; Bowers, John E
2014-10-20
We propose and analyze a novel highly integrated optical gyroscope using low loss silicon nitride waveguides. By integrating the active optical components on chip, we show the possibility of reaching a detection limit on the order of 19°/hr/√Hz in an area smaller than 10 cm(2). This study examines a number of parameters, including the dependence of sensitivity on sensor area.
Mobile Robot Integrated with Gyroscope by Using IKF
Surachai Panich; Nitin Afzulpurkar
2011-01-01
This paper mainly proposes absolute positioning instruments using camera positioning system and compass.The absolute positioning systems are used to estimate absolute position and orientation errors combined with estimated position and orientation from differential odometry integrated with gyroscope to calculate absolute position and orientation of mobile robot. In the method, the indirect Kalman filter is used to estimate absolute position and orientation errors and the estimated errors are ...
Polarization decoherence differential frequency-modulated continuous-wave gyroscope.
Zheng, Chao; Zheng, Gang; Han, Liwei; Luo, Jianhua; Teng, Fei; Wang, Bing; Song, Ping; Gao, Kun; Hou, Zhiqing
2014-12-01
A polarization decoherence differential frequency-modulated continuous-wave (FMCW) gyroscope is presented. The impact of coherent polarization crosstalk noise on the differential FMCW gyro is analyzed. In order to suppress coherent polarization crosstalk noise, a novel method was proposed to produce two incoherent orthogonal polarization narrow band beams from laser diode. In this way, the random drift has been reduced about one order.
Converging coolness and investigating its relation to user experience
Raptis, Dimitrios; Bruun, Anders; Kjeldskov, Jesper
2017-01-01
Recently a number of studies appeared that operationalised coolness and explored its relation to digital products. Literature suggests that perceived coolness is another factor of user experience, and this adds to an existing explosion of dimensions related to aesthetics, hedonic quality, pragmatic...... quality, attractiveness, etc. A critical challenge highlighted in prior research is to study the relationships among those factors and so far, no studies have empirically examined the relationship between coolness and other established user experience factors. In this paper, we address this challenge...... by presenting two studies one that focuses on factors from two cool questionnaires, and one that compares them against existing User eXperience (UX) factors. Our findings show that factors from the two cool questionnaires converge and they also converge to existing, established UX factors. Thus, 11 distinct...
Couples constructing their experiences of dementia: A relational perspective.
Merrick, Kimberley; Camic, Paul M; O'Shaughnessy, Margaret
2016-01-01
Many people with dementia are cared for by their spouse or partner, therefore there is a need to understand the ways in which dementia and couple relationships impact upon each other. This study aimed to contribute to our understanding of the experience of dementia from a relational perspective. Seven couples, in which one person had a diagnosis of dementia, were interviewed about their experience of being in a couple where one partner had a diagnosis of dementia. Using interpretative phenomenological analysis, five master themes were identified, which illustrated how couples constructed their experience of dementia in order to make sense of it, and describe the processes that they adopt in order to adjust to dementia. Findings were supported by existing empirical and theoretical literature and suggest that services and interventions could be enhanced if a relational understanding of dementia were more fully considered.
Dynamic Incentive Effects of Relative Performance Pay: A Field Experiment
J. Delfgaauw (Josse); A.J. Dur (Robert); J.A. Non (Arjan); W.J.M.I. Verbeke (Willem)
2010-01-01
textabstractWe conduct a field experiment among 189 stores of a retail chain to study dynamic incentive effects of relative performance pay. Employees in the randomly selected treatment stores could win a bonus by outperforming three comparable stores from the control group over the course of four w
Weight-Related Attitudes and Experiences of Nutrition Professionals
Learners will describe the attitudes and experiences of nutrition professionals regarding professional responsibility to model an appropriate weight status and the role of personal weight-related issues in nutrition counseling interactions. The purpose of this study was to describe the attitudes an...
Model experiments related to outdoor propagation over an earth berm
Rasmussen, Karsten Bo
1994-01-01
A series of scale model experiments related to outdoor propagation over an earth berm is described. The measurements are performed with a triggered spark source. The results are compared with data from an existing calculation model based upon uniform diffraction theory. Comparisons are made...
Fabrication and characterization of an SOI MEMS gyroscope
Weiwei, Zhong; Guowei, Han; Chaowei, Si; Jin, Ning; Fuhua, Yang
2013-06-01
This paper presents an SOI (silicon on insulator) MEMS (micro-electro-mechanical systems) vibratory gyroscope that was fabricated using bulk micromachining processes. In the gyroscope architecture, a frame structure that nests the proof mass is used to decouple the drive motion and sense motion. This approach ensures that the drive motion is well aligned with the designed drive axis, and minimizes the actual drive motion component along the sense detection axis. The thickness of the structural layer of the device is 100 μm, which induces a high elastic stiffness in the thickness direction, so it can suppress the high-order out-of-plane resonant modes to reduce deviation. In addition, the dynamics of the gyroscope indicate that higher driving mass brings about higher sensing displacements. The thick structural layer can improve the output of the device by offering a sufficient mass weight and large sensing capacitance. The preliminary test results of the vacuum packaged device under atmospheric pressure will be provided. The scale factor is 1.316 × 10-4 V/(deg/s), the scale factor nonlinearity and asymmetry are 1.87% and 0.36%, the zero-rate offset is 7.74 × 10-4 V, and the zero-rate stability is 404 deg/h, respectively.
A New Hybrid Gyroscope with Electrostatic Negative Stiffness Tuning
Xian Chu
2013-05-01
Full Text Available A variety of gyroscopes have been extensively studied due to their capability of precision detection of rotation rates and extensive applications in navigation, guidance and motion control. In this work, a new Hybrid Gyroscope (HG which combines the traditional Dynamically Tuned Gyroscope (DTG with silicon micromachined technology is investigated. The HG not only has the potentiality of achieving the same high precision as the traditional DTG, but also features a small size and low cost. The theoretical mechanism of the HG with a capacitance transducer and an electrostatic torquer is derived and the influence of the installation errors from the capacitance plate and the disc rotor module is investigated. A new tuning mechanism based on negative stiffness rather than the traditional dynamic tuning is proposed. The experimental results prove that the negative stiffness tuning is practicable and a tuning voltage of as high as 63 V is demonstrated. Due to the decreased installation error, the non-linearity of the scale factor is reduced significantly from 11.78% to 0.64%, as well as the asymmetry from 93.3% to 1.56% in the open loop condition. The rebalancing close-loop control is simulated and achieved experimentally, which proves that the fundamental principle of the HG is feasible.
A new hybrid gyroscope with electrostatic negative stiffness tuning.
Yang, Bo; Guan, Yumei; Wang, Shourong; Zou, Qi; Chu, Xian; Xue, Haiyan
2013-01-01
A variety of gyroscopes have been extensively studied due to their capability of precision detection of rotation rates and extensive applications in navigation, guidance and motion control. In this work, a new Hybrid Gyroscope (HG) which combines the traditional Dynamically Tuned Gyroscope (DTG) with silicon micromachined technology is investigated. The HG not only has the potentiality of achieving the same high precision as the traditional DTG, but also features a small size and low cost. The theoretical mechanism of the HG with a capacitance transducer and an electrostatic torquer is derived and the influence of the installation errors from the capacitance plate and the disc rotor module is investigated. A new tuning mechanism based on negative stiffness rather than the traditional dynamic tuning is proposed. The experimental results prove that the negative stiffness tuning is practicable and a tuning voltage of as high as 63 V is demonstrated. Due to the decreased installation error, the non-linearity of the scale factor is reduced significantly from 11.78% to 0.64%, as well as the asymmetry from 93.3% to 1.56% in the open loop condition. The rebalancing close-loop control is simulated and achieved experimentally, which proves that the fundamental principle of the HG is feasible.
An Advanced Micromachined Package for the Quartz Disk Resonant Gyroscope Project
National Aeronautics and Space Administration — The objective of this proposal is to demonstrate the feasibility of a fully packaged microelectromechanical (MEMS) gyroscope with a 7 milliarcsecond pointing...
Benchmarking NMR experiments: a relational database of protein pulse sequences.
Senthamarai, Russell R P; Kuprov, Ilya; Pervushin, Konstantin
2010-03-01
Systematic benchmarking of multi-dimensional protein NMR experiments is a critical prerequisite for optimal allocation of NMR resources for structural analysis of challenging proteins, e.g. large proteins with limited solubility or proteins prone to aggregation. We propose a set of benchmarking parameters for essential protein NMR experiments organized into a lightweight (single XML file) relational database (RDB), which includes all the necessary auxiliaries (waveforms, decoupling sequences, calibration tables, setup algorithms and an RDB management system). The database is interfaced to the Spinach library (http://spindynamics.org), which enables accurate simulation and benchmarking of NMR experiments on large spin systems. A key feature is the ability to use a single user-specified spin system to simulate the majority of deposited solution state NMR experiments, thus providing the (hitherto unavailable) unified framework for pulse sequence evaluation. This development enables predicting relative sensitivity of deposited implementations of NMR experiments, thus providing a basis for comparison, optimization and, eventually, automation of NMR analysis. The benchmarking is demonstrated with two proteins, of 170 amino acids I domain of alphaXbeta2 Integrin and 440 amino acids NS3 helicase.
A Highly Miniaturized Inertial Grade Gyroscope for Space Applications
Wiberg, D. V.; Challoner, A. D.; Shcheglov, K.; Hayworth, K.; Bae, S.; Yee, K.; Blaes, B.; DAgostino, S.; Stock, T.
2001-01-01
The evolution of inertial grade gyroscopes for space applications represents well over 50 years of technology development and an investment of hundreds of millions of dollars. The workhorse product which represents the current state-of-the art for commercially available high performance devices is the Litton-Hemishperical Resonator Gyro (HRG) Inertial Measurement Unit (IMU). This product has a performance figure of merit of 0.003 deg/hr bias drift, a volume of 567 cubic inches, weighs 19 pounds, draws about 30 watts and costs over 1 million each. Clearly devices of this magnitude are not conducive to the minimized mass, volume, power, and cost constraints of outer planet missions. An approach to breaking these potential barriers is the use of Microelectromechanical Systems (MEMS) based inertial devices. Although substantially reduced in size, mass power and cost, this approach has produced devices in the tactical performance range of greater than 1 deg/hour bias drift. This level of performance satisfies the preponderance of high market volume requirements such as automotive and tactical munitions but does not meet the limited market quantity requirements for the high precision space based market. Because of the very limited size of the space based market, there is little economic incentive for commercial fabricators of tactical grade devices to address the necessary performance improvements. The Jet Propulsion Laboratory (JPL) in conjunction with Boeing Space Systems (BSS) is addressing this void to satisfy our mutual requirements in this area. The project objective to is to achieve 0.01 deg/hr performance in an IMU which is less than 10 cubic inches in volume, weighs less than 0.5 pounds, draws less than 1 watt and is available in volume production for less than 2500. Reductions of this magnitude will be mission enabling capabilities for a variety of anticipated outer planet mission attributes such as autonomous control and docking, formation flying and robotic
Application of MEMS gyroscope and encoder in robot self-localization%MEMS陀螺与编码器在机器人自主定位中的应用
张磊; 蒋刚; 肖志峰; 叶登金
2011-01-01
为提高微机械陀螺仪输出精度及移动机器人定位精度,研究了基于微机械陀螺仪与光电编码器的移动机器人自主定位方法.实时小波滤波法算法去除微机械陀螺仪输出数据噪声；通过微陀螺精度校正平台,用加权最小二乘支持向量回归机算法对微机械的先验数据作回归运算,构造先验回归决策函数,运用回归决策函数补偿微机械陀螺仪输出误差,提高微机械陀螺仪的角速率输出准确度；实验证实了方法能较好提高了MEMS陀螺仪的准确度,可以应用于移动机器人的自主定位之中.%To improve output precision of MEMS gyroscope and positioning accuracy of the mobilerobot, a localization approach for mobile robot self-localization based on MEMS gyroscopes and optical en-coder is presentedAnd a real-time wavelet filter algorithm is used to remove the noise made by data outputof MEMS gyroscopes.Through the accuracy corrections equipment of MEMS gyroscopes ,prior data of MEMSgyroscope were taken as the input of weighted least squares support vector regression for prior regressiondecision function-To improve accuracy of the angular rate of gyroscope,the prior regression decision June-tion is used to compensate the output error of MEMS gyroscopes.The results of the experiment show that ac-curacy of gyroscope is improved,and can be used in the mobile robot self-localization.
International experience in the use of leasing relations in Ukraine
L.V. Mikhalchuk
2015-09-01
Full Text Available The article examines the market of leasing relations in the UK, Germany, France, the USA. Comparative analysis of development of leasing in foreign countries has been carried out in order to use international experience of leasing relations in Ukraine at the present stage of development of state economy. In spite of prevalence of leasing in developed countries, this kind of relationship is still uncommon in the economic environment of Ukraine because of its novelty and lack of experience. Relevance of leasing development in Ukraine, including the formation of leasing market, primarily is caused by a significant proportion of obsolete equipment and low efficiency of its use. One of solutions to these problems can be leasing which brings together all the elements of international trade, credit, and investment operations.
Elite Athletes experiences with risk related to Cardiac Screening
Christensen, Jonas Schmidt; Thing, Lone Friis
Elite Athletes experiences with risks related to Cardiac Screening Jonas Schmidt Christensen1, Lone Friis Thing1 1University of Copenhagen - Department of Nutrition, Exercise and Sports (NEXS), Cardiac screening of elite athletes are recommended by both the American Heart Association & the European...... is dominated by studies with a clinical medical focus and studies of athlete’s perspectives on cardiac screening are consequently an absence. By using an interpretive sociological perspective (Denzin 2001) and qualitative research done with elite athletes of both gender this paper seeks to explore how elite...... athletes experience risks associated with cardiac screening. To make possible an analysis of how elite athletes come to an understanding of and position themselves in relation to the risk discourse (Lupton 2013) they are met by, the focus is on Foucault’s technologies of the self and a subjectivity...
Yuan, Guangmin; Yuan, Weizheng; Xue, Liang; Xie, Jianbing; Chang, Honglong
2015-10-30
In this paper, the performance of two Kalman filter (KF) schemes based on the direct estimated model and differencing estimated model for input rate signal was thoroughly analyzed and compared for combining measurements of a sensor array to improve the accuracy of microelectromechanical system (MEMS) gyroscopes. The principles for noise reduction were presented and KF algorithms were designed to obtain the optimal rate signal estimates. The input rate signal in the direct estimated KF model was modeled with a random walk process and treated as the estimated system state. In the differencing estimated KF model, a differencing operation was established between outputs of the gyroscope array, and then the optimal estimation of input rate signal was achieved by compensating for the estimations of bias drifts for the component gyroscopes. Finally, dynamic simulations and experiments with a six-gyroscope array were implemented to compare the dynamic performance of the two KF models. The 1σ error of the gyroscopes was reduced from 1.4558°/s to 0.1203°/s by the direct estimated KF model in a constant rate test and to 0.5974°/s by the differencing estimated KF model. The estimated rate signal filtered by both models could reflect the amplitude variation of the input signal in the swing rate test and displayed a reduction factor of about three for the 1σ noise. Results illustrate that the performance of the direct estimated KF model is much higher than that of the differencing estimated KF model, with a constant input signal or lower dynamic variation. A similarity in the two KFs' performance is observed if the input signal has a high dynamic variation.
Guangmin Yuan
2015-10-01
Full Text Available In this paper, the performance of two Kalman filter (KF schemes based on the direct estimated model and differencing estimated model for input rate signal was thoroughly analyzed and compared for combining measurements of a sensor array to improve the accuracy of microelectromechanical system (MEMS gyroscopes. The principles for noise reduction were presented and KF algorithms were designed to obtain the optimal rate signal estimates. The input rate signal in the direct estimated KF model was modeled with a random walk process and treated as the estimated system state. In the differencing estimated KF model, a differencing operation was established between outputs of the gyroscope array, and then the optimal estimation of input rate signal was achieved by compensating for the estimations of bias drifts for the component gyroscopes. Finally, dynamic simulations and experiments with a six-gyroscope array were implemented to compare the dynamic performance of the two KF models. The 1σ error of the gyroscopes was reduced from 1.4558°/s to 0.1203°/s by the direct estimated KF model in a constant rate test and to 0.5974°/s by the differencing estimated KF model. The estimated rate signal filtered by both models could reflect the amplitude variation of the input signal in the swing rate test and displayed a reduction factor of about three for the 1σ noise. Results illustrate that the performance of the direct estimated KF model is much higher than that of the differencing estimated KF model, with a constant input signal or lower dynamic variation. A similarity in the two KFs’ performance is observed if the input signal has a high dynamic variation.
Converging coolness and investigating its relation to user experience
Raptis, Dimitrios; Bruun, Anders; Kjeldskov, Jesper
2016-01-01
cool and UX factors converge into 5 for the case of mobile devices. Our findings are important for researchers, as we demonstrate through a validated model that coolness is part of UX research, as well as for practitioners, by developing a questionnaire that can reliably measure both perceived inner......Recently a number of studies appeared that operationalised coolness and explored its relation to digital products. Literature suggests that perceived coolness is another factor of user experience, and this adds to an existing explosion of dimensions related to aesthetics, hedonic quality, pragmatic...
Electrostatic stiffness correction for quadrature error in decoupled dual-mass MEMS gyroscope
Li, Hongsheng; Cao, Huiliang; Ni, Yunfang
2014-07-01
This paper proposes an electrostatic stiffness correction method for the quadrature error (QUER) in a decoupled dual-mass gyroscope structure. The QUER is caused by the imperfections during the structure manufacturing process, and the two masses usually have different QUERs. The harm contribution to the Coriolis signal is analyzed and quantified. The generating forms of QUER motion in both masses are analyzed, the correction electrodes' working principle is introduced, and a single mass individual correction method is proposed. The QUER stiffness correction system is designed based on a PI controller, and the experiments are arranged to verify the theoretical analysis. The bias stability decreases from 2.06 to 0.64 deg/h after the QUER correction, and the parameters of scale factor such as nonlinearly, asymmetry, and repeatability, reduce from 143, 557, and 210 ppm to 84, 242, and 175 ppm, respectively.
A D-optimal Multi-position Calibration Method for Dynamically Tuned Gyroscopes
FU Li; ZHU Yongquan; WANG Lingling; WANG Xinling
2011-01-01
This paper presents a novel experimental design to greatly improve the calibration accuracy of the acceleration-insensitive bias and the acceleration-sensitive bias of the dynamically tuned gyroscopes (DTGs). In order to reduce experimental cost, the D-optimal criteria with constraints are constructed. The turntable positions and the number of test points are chosen to build D-optimal experimental designs. The D-optimal experimental designs are tested by multi-position calibration experiment for tactical-grade DTGs. Test results show that, with the same cost, the fit uncertainty is reduced by about 50％ by using the D-optimal 8-position experimental procedure, compared to using a defacto standard experimental procedure in ANSI/IEEE Std 813-1988. Furthermore, the new experimental procedure almost achieves optimal accuracy with only 12-position which is half the cost of the widely adopted 24-position experimental procedure for achieving optimal accuracy.
Measurements of complex coupling coefficients in a ring resonator of a laser gyroscope
Bessonov, A. S.; Makeev, A. P.; Petrukhin, E. A.
2017-07-01
A method is proposed for measuring complex coupling coefficients in a ring optical resonator in the absence of an active gas mixture. A setup is described on which measurements are performed in ring resonators of ring He-Ne lasers with a wavelength of 632.8 nm. A model of backscattering field interference between conservative and dissipative sources is presented. Within the framework of this model, the unusual behaviour of backscattering fields in ring resonators observed in experiments is explained: a significant difference in the moduli of coupling coefficients of counterpropagating waves and variation of the magnitude of the total phase shift in a wide range. It is proposed to use this method as a metrological method when assembling and aligning a ring resonator of a laser gyroscope.
Lin, Jian; Liu, Jiaming; Zhang, Hao; Li, Wenxiu; Zhao, Lu; Jin, Junjie; Huang, Anping; Zhang, Xiaofu; Xiao, Zhisong
2016-12-01
Rigorous expressions of resonant frequency shift (RFS) in anomalous dispersion enhanced resonant optical gyroscopes (ADEROGs) are deduced without making approximation, which provides a precise theoretical guidance to achieve ultra-sensitive ADEROGs. A refractive index related modification factor is introduced when considering special theory of relativity (STR). We demonstrate that the RFS will not be ”infinitely large” by using critical anomalous dispersion (CAD) and negative modification does not exist, which make the mechanism of anomalous dispersion enhancement clear and coherent. Although step change of RFS will happen when the anomalous dispersion condition varies, the amplification of RFS is limited by attainable variation of refractive index in practice. Moreover, it is shown that the properties of anomalous dispersion will influence not only the amplification of RFS, but also the detection range of ADEROGs.
Changsheng Li; Chunxi Zhang; Ningfang Song; Hongjie Xu
2011-01-01
@@ A novel polarization maintaining fiber (PMP) loop is proposed and used for an interferometric fiber optic gyroscope (FOG). By splicing a conventional PMF loop with two pigtailed polarization beam splitters, polarized light can be guided to propagate along the slow and fast axes of the PMF in sequence to double its effective optical length in the loop. In particular, the resultant optical length in the combined loop is partially self-compensated for some external disturbances, such as transverse strain. Primary experiments on the FOG using the proposed loop demonstrate that the average static bias deviation between -40 and +60 ℃ is less than 0.050 deg./h, and the average bias variation under conventional random vibration test is less than 0.10 deg./h.%A novel polarization maintaining fiber (PMF) loop is proposed and used for an interferometric fiber optic gyroscope (FOG). By splicing a conventional PMF loop with two pigtailed polarization beam splitters,polarized light can be guided to propagate along the slow and fast axes of the PMF in sequence to double its effective optical length in the loop. In particular, the resultant optical length in the combined loop is partially self-compensated for some external disturbances, such as transverse strain. Primary experiments on the FOG using the proposed loop demonstrate that the average static bias deviation between -40 and +60 ℃ is less than 0.050 deg./h, and the average bias variation under conventional random vibration test is less than 0.10 deg./h.
Smartstones: a small e-compass, accelerometer and gyroscope embedded in stones
Gronz, Oliver; Hiller, Priska H.; Wirtz, Stefan; Becker, Kerstin; Iserloh, Thomas; Aberle, Jochen; Casper, Markus C.
2015-04-01
Pebbles or rock fragments influence soil erosion processes in various ways: they can protect the soil but also enhance the erosion as soon as they are moved by water and impact onto soil. So far, stone-embedded devices to measure the movements have been quite big, up to several decimetres, which does not allow for the analysis of pebbles from medium and coarse gravel classes. In this study, we used a novel device called Smartstones, which is significantly smaller. The Smartstone device's dimensions are 55 mm in length, 8 mm in diameter and an approximately 70 mm long flexible antenna (device developer: SMART-RFID solutions Rheinberg, Germany). It is powered by two button cells, contains an own data storage and is able to wait inactive for longer times until it is activated by movement. It communicates via active RFID (radio frequency identification) technology to a Linux gateway, which stores the sensor data in a database after transmission and is able to handle several devices simultaneously. The device contains a Bosch sensor that measures magnetic flux density, acceleration and rotation, in each case for / around three axes. In our study, the device has been used in a laboratory flume (270 cm in length, 5° to 10° slope, approx. 2 cm water level, mean flow velocities between 0.66 and 1 ms-1) in combination with a high speed camera to capture the movement of the pebbles. The simultaneous usage of two capture devices allows for a comparison of the results: movement patterns derived from image analysis and sensor data analysis. In the device's first software version, all three sensors - acceleration, compass, and gyroscope - were active. The acquisition of all values resulted in a sampling rate of 10 Hz. After the experiments using this setup, the data analysis of the high speed images and the device's data showed that the pebble reached rotation velocities beyond 5 rotations per second, even on the relatively short flume and low water levels. Thus, the device
Touch and relate: body experience among staff in habilitation services
Görel Råsmark
2014-02-01
Full Text Available In habilitation centres staff meet children with different impairments, children who need extensive support and training while growing up. A prevailing biomedical view of the body in habilitation services is gradually becoming supplemented by a perspective on the body as constantly involved in experiencing and communicating, the latter involving also the bodies of the therapists. Investigating body experience in habilitation staff in their encounters with the children may provide concepts that make it easier to reflect on what is going on in the interaction. When shared among larger number of peers and supported by further research in the field, reflected body experience may become a substantial aspect of professional self-knowledge. Our aim with this study was to contribute to the understanding of what it means to be a body for other bodies in the specific relational context of child habilitation, and more specifically to investigate what role the therapists’ body experience may play for professional awareness and practice. In the study, five physiotherapists and three special-education teachers spoke of physical and emotional closeness (the body as affection but also of a provoking closeness (the body as provoked with the children and of how their own body experience made them more attentive to the children's experience (the body as reference. Situations that included bodily limitations (the body as restriction were described, as were situations where the body came into focus through the gazes of others or one's own (the body as observed. The body was described as a flexible tool (the body as tool, and hands were given an exclusive position as a body part that was constantly communicating. Three shifts of intentionality that form a comprehensive structure for this body experience were discerned. When professional reflection is evoked it may further body awareness, deepen reflection in practice and strengthen intercorporeality.
Design and fabrication of a biomimetic gyroscope inspired by the fly's haltere
Droogendijk, H.; Brookhuis, R.A.; Boer, de M.J.; Sanders, R.G.P.; Krijnen, G.J.M.
2012-01-01
We report on the design and fabrication of a MEMS-based gyroscopic system inspired by the fly's haltere system. Two types of so-called biomimetic gyroscopes have been designed, fabricated and their drive mode has been characterized. First measurements indicate excitable gyropscopes with natural freq
A gyroscope fabrication method for high sensitivity and robustness to fabrication tolerances
Sung, Jungwoo; Kim, Jin Young; Seok, Seyeong; Kwon, Hyuckjin J.; Kim, Minseo; Kim, Geonhwee; Lim, Geunbae
2014-07-01
MEMS gyroscopes have favorable characteristics, including small size, high throughput, and low cost. The performance of MEMS gyroscopes depends on the displacement sensitivity of the capacitors. In this paper, we describe the fabrication of 300-µm-thick gyroscopes that can provide high displacement sensitivity and are robust to fabrication tolerances, i.e. deep reactive ion etch (DRIE) rate uniformity. When thick structures are perforated using DRIE to achieve high-aspect-ratio features, footing is commonly observed. However, we describe a fabrication method that circumvents problems associated with footing and side-wall etching, so that the gyroscopes can have uniform dimensions and small variations across the wafer. Using a post-fabrication translation approach, the position of capacitors is modified following DRIE, and the gap in the gyroscopes can be reduced to 3 μm, which leads to an aspect ratio of 100. Using this method, we fabricated MEMS gyroscopes that can overcome the DRIE aspect ratio limit and have capacitors with higher sensitivities than those of other gyroscopes, which typically employ substrates that are less than 100 µm thick. The gyroscope had a resonant frequency of 9.91 kHz, a quality factor of 2500 and a sensitivity of 23 mV/[deg/s].
Design and fabrication of a biomimetic gyroscope inspired by the fly’s haltere
Droogendijk, H.; Brookhuis, R.A.; Boer, de M.J.; Sanders, R.G.P.; Krijnen, G.J.M.
2013-01-01
We report on the design and fabrication of a MEMS-based gyroscopic system inspired by the fly’s haltere system. Two types of so-called biomimetic gyroscopes have been designed, fabricated and partially characterized. First measurements indicate excitable gyropscopes with natural frequencies in the o
Droogendijk, H.; Brookhuis, R.A.; Boer, de M.J.; Sanders, R.G.P.; Krijnen, G.J.M.
2014-01-01
Flies use so-called halteres to sense body rotation based on Coriolis forces for supporting equilibrium reflexes. Inspired by these halteres, a biomimetic gimbal-suspended gyroscope has been developed using microelectromechanical systems (MEMS) technology. Design rules for this type of gyroscope are
Gyroscopes and gyro-stabilized systems. Citations from the NTIS data base
Young, C. G.
1980-05-01
The theory, design, construction, applications, and uses of gyroscopes are described in approximately 188 citations. Fiberoptic, electrostatic, microelectrostatic, cryogenic or super conducting, nuclear magnetic gyroscopes are discussed. Geophysical measurements, verifications of Einstein's theories, missile guidance, inertial navigation, platform stabilization are included.
1.3μm Superluminescence Diode with Butterfly Package for Fiber Gyroscope
无
2001-01-01
Superluminescence diode(SLD) modules with wide spectrum characteristics are required in fiber gyroscopes. A 1.3μm butterfly packaged superluminescence diode with the spectrum width over 30nm is reported and recent advances in process of SLD is described in the paper. The SLD modules have been applied to fiber gyroscopes.
Reproducibility of a 3-dimensional gyroscope in measuring shoulder anteflexion and abduction
Penning, L.I.F.; Guldemond, N.A.; De Bie, R.A.; Walenkamp, G.H.I.M.
2012-01-01
Background: Few studies have investigated the use of a 3-dimensional gyroscope for measuring the range of motion (ROM) in the impaired shoulder. Reproducibility of digital inclinometer and visual estimation is poor. This study aims to investigate the reproducibility of a tri axial gyroscope in measu
Stability analysis of the Gyroscopic Power Take-Off wave energy point absorber
Nielsen, Søren R. K.; Zhang, Zili; Kramer, Morten Mejlhede
2015-01-01
The Gyroscopic Power Take-Off (GyroPTO) wave energy point absorber consists of a float rigidly connected to a lever. The operational principle is somewhat similar to that of the so-called gyroscopic hand wrist exercisers, where the rotation of the float is brought forward by the rotational partic...
Digital Readout System for Micromachined Gyroscope and Analysis for its Demodulation Algorithm
ZHOU Bin; GAO Zhong-yu; CHEN Huai; ZHANG Rong; CHEN Zhi-yong
2006-01-01
A new digital readout system for micromachined gyroscope has been proposed to implement flexible parameter adiustment,improve the control performance of gyroscope,and make error compensation.By digitalizing the output of the gyroscope,this system uses a floatingtype digital signal processor(DSP)to process the signal demodulation and achieve the feedback conffol of the gyroscope.Therefore.the small change of capacitance in the micromachined gyroscope Can be detected.A new demodulation algorithm of least mean square demodulation(LMSD)has been developed inside DSP Simulation and measurement results show that LMSD Can improve 29%of the noise performance compared with the typical multiplication method.In air pressure.a kind ofvibration-wheel micmmachined over the 100-Hz bandwidth by using this digital readout technology.
Fan Shang-Chun; Li Yan; Guo Zhan-She; Li Jing; Zhuang Hai-Han
2012-01-01
Dynamic characteristics of the resonant gyroscope are studied based on the Mathieu equation approximate solution in this paper.The Mathieu equation is used to analyze the parametric resonant characteristics and the approximate output of the resonant gyroscope.The method of small parameter perturbation is used to analyze the approximate solution of the Mathieu equation.The theoretical analysis and the numerical simulations show that the approximate solution of the Mathieu equation is close to the dynamic output characteristics of the resonant gyroscope.The experimental analysis shows that the theoretical curve and the experimental data processing results coincide perfectly,which means that the approximate solution of the Mathieu equation can present the dynamic output characteristic of the resonant gyroscope.The theoretical approach and the experimental results of the Mathieu equation approximate solution are obtained,which provides a reference for the robust design of the resonant gyroscope.
Z-Axis Micromachined Tuning Fork Gyroscope with Low Air Damping
Minh Ngoc Nguyen
2017-02-01
Full Text Available This paper reports on the design and fabrication of a z-axis tuning fork gyroscope which has a freestanding architecture. In order to improve the performance of the tuning fork gyroscope by eliminating the influence of the squeeze-film air damping, the driving and sensing parts of the gyroscope were designed to oscillate in-plane. Furthermore, by removing the substrate underneath the device, the slide-ﬁlm air damping in the gap between the proof masses and the substrate was eliminated. The proposed architecture was analyzed by the finite element method using ANSYS software. The simulated frequencies of the driving and sensing modes were 9.788 and 9.761 kHz, respectively. The gyroscope was fabricated using bulk micromachining technology. The quality factor and sensitivity of the gyroscope operating in atmospheric conditions were measured to be 111.2 and 11.56 mV/°/s, respectively.
The dissociative experiences taxon is related to fantasy proneness.
Giesbrecht, Timo; Merckelbach, Harald; Geraerts, Elke
2007-09-01
Some authors have argued that nonpathological dissociation should be distinguished from a taxon form of pathological dissociation, which is indexed by the Dissociative Experiences Scale Taxon (DES-T). We tested to what extent DES-T scores are independent from fantasy immersion and whether DES-T scores are uniquely related to trauma self-reports. To this end, subsamples of undergraduate students (n = 930), healthy adults (n = 20), schizophrenic patients (n = 22), borderline personality disordered patients (n = 20), patients with mood disorder without psychosis (n = 19), and women with a history of childhood sexual abuse (n = 55) completed the Dissociative Experiences Scale and a measure of fantasy immersion. DES-T scores were related to absorption and fantasy immersion to a lesser extent than the original DES. However, the fact that nontrivial percentages within all groups, except for the healthy adults, were classified as taxon members casts doubts on the assumption that DES-T is a reliable index of pathological dissociation. Also, we found that the DES-T was not exclusively related to reports of childhood sexual abuse.
Measuring the Virgo area tilt noise with a laser gyroscope
Belfi, Jacopo; Bosi, Filippo; Carelli, Giorgio; Di Virgilio, Angela; Maccioni, Enrico; Stefani, Fabio
2011-01-01
We report on the measurements of tilt noise performed at the Virgo site with a ring laser gyroscope. The apparatus is a He-Ne laser operating in a square cavity mounted on a vertical plane perpendicular to the north-south arm of the inteferometer. We discuss the possibility of using the ring laser signal to improve the performances of the control system of the Virgo seismic suspensions. The comparison between the ring laser signal and the control signals for the longitudinal translations of the inverted pendulum (IP) shows remarkable coherence in the frequency range 20-200 mHz.
Motion of the Tippe Top : Gyroscopic Balance Condition and Stability
Ueda, Takahiro(Nikhef Theory Group, Science Park 105, 1098 XG, Amsterdam, The Netherlands); Sasaki, Ken; Watanabe, Shinsuke
2005-01-01
We reexamine a very classical problem, the spinning behavior of the tippe top on a horizontal table. The analysis is made for an eccentric sphere version of the tippe top, assuming a modified Coulomb law for the sliding friction, which is a continuous function of the slip velocity $\\vec v_P$ at the point of contact and vanishes at $\\vec v_P=0$. We study the relevance of the gyroscopic balance condition (GBC), which was discovered to hold for a rapidly spinning hard-boiled egg by Moffatt and S...
Indefinite damping in mechanical systems and gyroscopic stabilization
Kliem, Wolfhard; Pommer, Christian
2009-01-01
This paper deals with gyroscopic stabilization of the unstable system Mx + D(x) over dot + K-x = 0, with positive definite mass and stiffness matrices M and K, respectively, and an indefinite damping matrix D. The main question if for which skew-symmetric matrices G the system Mx (D+ G)(x) over d...... + K-x = 0 can become stable? After investigating special cases we find an appropriat solution of the Lyapunov matrix equation for the general case. Examples show the deviation of the stability limit found by the Lyapunov method from the exact value....
Assessment of postural stability in patients with cerebellar disease using gyroscope data.
Kutílek, Patrik; Socha, Vladimír; Čakrt, Ondřej; Svoboda, Zdeněk
2015-07-01
This study examines a relatively new method of studying and quantifying human postural stability in patients with degenerative cerebellar disease. Trunk sway and feet sway were measured during quiet stance. To test the method, ten patients and eleven healthy subjects performed two different stance tasks: standing with eyes open on a firm surface and standing with eyes closed on a foam support surface. Data were recorded using three body-worn gyroscopes (Xsens Technologies B.V.) to measure roll and pitch angular movements of the lower trunk, and left and right foot. The pitch versus roll plots of the trunk and feet were created, and the areas of the convex hull shapes were calculated. It was found that the area of the convex hull of the pitch versus roll plots is suitable for the identification of postural instability disorders caused by degenerative cerebellar disease.
Statistical Extremes of Turbulence and a Cascade Generalisation of Euler's Gyroscope Equation
Tchiguirinskaia, Ioulia; Scherzer, Daniel
2016-04-01
Turbulence refers to a rather well defined hydrodynamical phenomenon uncovered by Reynolds. Nowadays, the word turbulence is used to designate the loss of order in many different geophysical fields and the related fundamental extreme variability of environmental data over a wide range of scales. Classical statistical techniques for estimating the extremes, being largely limited to statistical distributions, do not take into account the mechanisms generating such extreme variability. An alternative approaches to nonlinear variability are based on a fundamental property of the non-linear equations: scale invariance, which means that these equations are formally invariant under given scale transforms. Its specific framework is that of multifractals. In this framework extreme variability builds up scale by scale leading to non-classical statistics. Although multifractals are increasingly understood as a basic framework for handling such variability, there is still a gap between their potential and their actual use. In this presentation we discuss how to dealt with highly theoretical problems of mathematical physics together with a wide range of geophysical applications. We use Euler's gyroscope equation as a basic element in constructing a complex deterministic system that preserves not only the scale symmetry of the Navier-Stokes equations, but some more of their symmetries. Euler's equation has been not only the object of many theoretical investigations of the gyroscope device, but also generalised enough to become the basic equation of fluid mechanics. Therefore, there is no surprise that a cascade generalisation of this equation can be used to characterise the intermittency of turbulence, to better understand the links between the multifractal exponents and the structure of a simplified, but not simplistic, version of the Navier-Stokes equations. In a given way, this approach is similar to that of Lorenz, who studied how the flap of a butterfly wing could generate
Occupational health-related experiences in rural Tasmania.
Newman, Barbara; Berens, Heidi
2010-07-01
This descriptive, explorative study sought to identify the occupational-related health experiences of community nurses in their workday within rural North West Tasmania. Tasmania is one of eight states and territories that form Australia. The findings indicate the majority of community nurses consider their health average or better, although 30% reported being overweight; 5% reported smoking; 60% reported feeling tense, anxious or depressed sometimes during the week. In the 12 months prior to survey 48% of participants had experienced a work-related injury or illness. At least two thirds of participants spent an average of 1.5 hours teaching nursing students and 2 hours teaching medical students, per week. Hazards (needlestick injury, items obstructing passageways, debris within homes), dogs and use of mobile telephones were regularly associated with weekly work incidents. Interestingly, more time was spent in a day on documentation than with clients or professional development.
PATIENTS' AND RELATIVES' EXPERIENCES OF PERITONITIS WHEN USING PERITONEAL DIALYSIS.
Baillie, Jessica; Lankshear, Annette
2015-09-01
Internationally, increasing numbers of patients are requiring treatment for end-stage kidney disease and greater use of peritoneal dialysis is thus being promoted. However, peritonitis can be a significant problem in this population. It is the leading cause of technique failure in patients using peritoneal dialysis and results in considerable morbidity and mortality. There is a dearth of research exploring patients' and their families' experiences of peritonitis. The aim of this paper is to explore patients' and their families' perspectives and experiences of peritonitis. An ethnographic study was conducted in 2011 in the United Kingdom. Sixteen patients and nine of their relatives were recruited through purposive and convenience sampling. In-depth interviews were undertaken with patients and their families, who were also observed using peritoneal dialysis in their homes. The data were analysed thematically using Wolcott's (1994) three-stage approach. This article describes four themes: learning about the risk of peritonitis; measures taken to prevent the infection; how participants monitored continuously for signs and symptoms of the infection; how they then identified and intervened once peritonitis was suspected. Overall, peritonitis was associated with fear and uncertainty, pain and learning from episodes of the infection. Overall, peritonitis was a distressing experience that participants sought to prevent. However, there was some confusion amongst participants about the signs and symptoms of the infection and further education for patients and their families is thus crucial. © 2015 European Dialysis and Transplant Nurses Association/European Renal Care Association.
Track Detection in Railway Sidings Based on MEMS Gyroscope Sensors
Miguel A. López
2012-11-01
Full Text Available The paper presents a two-step technique for real-time track detection in single-track railway sidings using low-cost MEMS gyroscopes. The objective is to reliably know the path the train has taken in a switch, diverted or main road, immediately after the train head leaves the switch. The signal delivered by the gyroscope is first processed by an adaptive low-pass filter that rejects noise and converts the temporal turn rate data in degree/second units into spatial turn rate data in degree/meter. The conversion is based on the travelled distance taken from odometer data. The filter is implemented to achieve a speed-dependent cut-off frequency to maximize the signal-to-noise ratio. Although direct comparison of the filtered turn rate signal with a predetermined threshold is possible, the paper shows that better detection performance can be achieved by processing the turn rate signal with a filter matched to the rail switch curvature parameters. Implementation aspects of the track detector have been optimized for real-time operation. The detector has been tested with both simulated data and real data acquired in railway campaigns.
Track detection in railway sidings based on MEMS gyroscope sensors.
Broquetas, Antoni; Comerón, Adolf; Gelonch, Antoni; Fuertes, Josep M; Castro, J Antonio; Felip, Damià; López, Miguel A; Pulido, José A
2012-11-23
The paper presents a two-step technique for real-time track detection in single-track railway sidings using low-cost MEMS gyroscopes. The objective is to reliably know the path the train has taken in a switch, diverted or main road, immediately after the train head leaves the switch. The signal delivered by the gyroscope is first processed by an adaptive low-pass filter that rejects noise and converts the temporal turn rate data in degree/second units into spatial turn rate data in degree/meter. The conversion is based on the travelled distance taken from odometer data. The filter is implemented to achieve a speed-dependent cut-off frequency to maximize the signal-to-noise ratio. Although direct comparison of the filtered turn rate signal with a predetermined threshold is possible, the paper shows that better detection performance can be achieved by processing the turn rate signal with a filter matched to the rail switch curvature parameters. Implementation aspects of the track detector have been optimized for real-time operation. The detector has been tested with both simulated data and real data acquired in railway campaigns.
Design, modelling and simulation of vibratory micromachined gyroscopes
Mohite, Suhas; Patil, Nishad; Pratap, Rudra [CranesSci MEMS Lab, Department of Mechanical Engineering, Indian Institute of Science, Bangalore, 560012 (India)
2006-04-01
Among various MEMS sensors, a rate gyroscope is one of the most complex sensors from the design point of view. The gyro normally consists of a proof mass suspended by an elaborate assembly of beams that allow the system to vibrate in two transverse modes. The structure is normally analysed and designed using commercial FEM packages such as ANSYS or MEMS specific commercial tools such as Coventor or Intellisuite. In either case, the complexity in analysis rises manyfolds when one considers the etch hole topography and the associated .uid flow calculation for damping. In most cases, the FEM analysis becomes prohibitive and one resorts to equivalent electrical circuit simulations using tools like SABER in Coventor. Here, we present a simpli.ed lumped parameter model of the tuning fork gyro and show how easily it can be implemented using a generic tool like SIMULINK. The results obtained are compared with those obtained from more elaborate and intense simulations in Coventor. The comparison shows that lumped parameter SIMULINK model gives equally good results with fractional e.ort in modelling and computation. Next, the performance of a symmetric and decoupled vibratory gyroscope structure is also evaluated using this approach and a few modifications are made in this design to enhance the sensitivity of the device.
Track Detection in Railway Sidings Based on MEMS Gyroscope Sensors
Broquetas, Antoni; Comerón, Adolf; Gelonch, Antoni; Fuertes, Josep M.; Castro, J. Antonio; Felip, Damià; López, Miguel A.; Pulido, José A.
2012-01-01
The paper presents a two-step technique for real-time track detection in single-track railway sidings using low-cost MEMS gyroscopes. The objective is to reliably know the path the train has taken in a switch, diverted or main road, immediately after the train head leaves the switch. The signal delivered by the gyroscope is first processed by an adaptive low-pass filter that rejects noise and converts the temporal turn rate data in degree/second units into spatial turn rate data in degree/meter. The conversion is based on the travelled distance taken from odometer data. The filter is implemented to achieve a speed-dependent cut-off frequency to maximize the signal-to-noise ratio. Although direct comparison of the filtered turn rate signal with a predetermined threshold is possible, the paper shows that better detection performance can be achieved by processing the turn rate signal with a filter matched to the rail switch curvature parameters. Implementation aspects of the track detector have been optimized for real-time operation. The detector has been tested with both simulated data and real data acquired in railway campaigns. PMID:23443376
刘宇; 段耀宇; 刘利; 潘英俊
2012-01-01
为了提高悬臂梁振动陀螺仪在惯性测量系统中的测量精度,改进了悬臂梁振动陀螺仪的敏感结构,开发了基于该陀螺仪的测量系统,研究了改进悬臂梁陀螺仪的结构特性、温度特性、零位漂移和线性度.首先,根据悬臂梁振动陀螺仪的工作原理分析了影响其测量精度的原因.针对原有悬臂梁振动陀螺仪压电片耦合结构的不足提出了一种新的压电片耦合结构.接着,结合50、60、100mm悬臂梁和ANSYS软件对改进结构进行了建模仿真,证明了新结构的工程可行性.最后,基于改进结构制作了陀螺仪样机,并进行了相关的测试实验.仿真实验和样机实验表明,改进后的陀螺仪灵敏度平均提高了8.73％,25℃时的零位漂移平均下降了30.5％,温度漂移平均降低了10％,证明了新结构陀螺仪在工程应用中的可行性.%To improve the measurement accuracy of a cantilever vibration gyroscope in an inertial measurement system, the sensitive structure of the cantilever vibration gyroscope was modified and a measurement system was developed based on the gyroscope. The structural and temperature characteristics of the improved gyroscope were analyzed and the zero drift and linearity were researched in detail. Firstly, the reasons that affect the gyroscope measurement accuracy were analyzed base on the working principle of the cantilever vibration gyroscope. According to the insignificance of the piezoelectric film coupling structure of the original cantilever vibration gyroscope, a new piezoelectric film coupling structure was proposed. Then, the new structure was simulated by ANSYS software combined with 50, 60, 100 mmcantilevers to prove its engineering feasibility. Finally, a prototype of thegyroscope based on the new structure and test performance was produced in a laboratory. Simulation and prototype experiments show that the average sensitivity of the new structure gyroscope increases by 8. 73% > and
Behavior of a test gyroscope moving towards a rotating traversable wormhole
Chakraborty, Chandrachur; Pradhan, Parthapratim
2017-03-01
The geodesic structure of the Teo wormhole is briefly discussed and some observables are derived that promise to be of use in detecting a rotating traversable wormhole indirectly, if it does exist. We also deduce the exact Lense-Thirring (LT) precession frequency of a test gyroscope moving toward a rotating traversable Teo wormhole. The precession frequency diverges on the ergoregion, a behavior intimately related to and governed by the geometry of the ergoregion, analogous to the situation in a Kerr spacetime. Interestingly, it turns out that here the LT precession is inversely proportional to the angular momentum (a) of the wormhole along the pole and around it in the strong gravity regime, a behavior contrasting with its direct variation with a in the case of other compact objects. In fact, divergence of LT precession inside the ergoregion can also be avoided if the gyro moves with a non-zero angular velocity in a certain range. As a result, the spin precession frequency of the gyro can be made finite throughout its whole path, even very close to the throat, during its travel to the wormhole. Furthermore, it is evident from our formulation that this spin precession not only arises due to curvature or rotation of the spacetime but also due to the non-zero angular velocity of the spin when it does not move along a geodesic in the strong gravity regime. If in the future, interstellar travel indeed becomes possible through a wormhole or at least in its vicinity, our results would prove useful in determining the behavior of a test gyroscope which is known to serve as a fundamental navigation device.
An Overview of A Perturbation Analysis for Uni-directionally Coupled Vibratory Gyroscopes
Vu, Huy; Palacios, Antonio; In, Visarath; Longhini, Patrick; Neff, Joseph
2011-04-01
The complex behaviours of gyroscope systems have been scientifically researched and thoroughly studied for decades. Most of scientific research involving gyroscopes specifically concentrates on studying the designs and fabrications at the circuitry level. Although gaining a recent popularity with the low cost of MEMS device that offers an attractive approach for gyroscope fabrications, its performance is far from meeting the requirements for an inertial grade guidance system. To improve the performance, our current research is theoretically focusing upon investigating the dynamics of vibratory gyroscopes coupled in a ring configuration. Particularly, a certain topology of arrangements among coupled gyroscopes can be designed and studied to enhance robustness. The main operation depends mostly on an external source for a stable oscillation in the drive axis, while an oscillatory motion in the sense axis, which is used to detect an angular rate of rotation, is enabled through the transfers of energy from the drive via the Coriolis force. With the mathematical model depicted as Duffing oscillators, however, by adding a certain coupling among gyroscopes, a similar behavior to a Duffing oscillator is expected, only with more complicated dynamics at a higher dimension. A number of Perturbation methods have popularly been carried out, to seek for a general asymptotic solution of typical Duffing oscillators. In this work as an overview, the two-time scale Perturbation expansion is asymptotically applied on the uni-directionally coupled vibratory gyroscopes to find an analytical solution which is then compared to the numerical one.
Miyake, Yoshinori; Hirata, Masaki; Suzuki, Kenichiro
2012-09-01
Over the past ten years, much effort to develop microelectromechanical system (MEMS) gyroscopes with the “tactical” and “inertial” grade has been made. Although several techniques are proposed to increase the sensitivity, each of them has serious tradeoffs with other characteristics. We propose a new approach to accomplish the increase in sensitivity. The overall gyroscope consists of gyroscope elements arrayed in an X-Y matrix. Each gyroscope element is connected with two types of beams, coupling and connecting beams, and is excited in the antiphase vibration mode. First, this array configuration takes the advantage of the large scale factor of N2, the square of the number of elements, for the sensitivity over a simply large chip (the sensitivity is proportional to N). Second, the vibrational characteristics are not changed from those for a single element irrespective of the number of elements. Therefore, much effort in design can be saved. 1×2 and 2×2 arrays with the resonant frequency of approximately 5 kHz were fabricated and evaluated in terms of the resonant frequency and amplitude for each element. They agreed well with those of a single gyroscope. This indicates that the proposed array helps to reduce the task of frequency tuning, which is needed for conventional 1×2 gyroscope arrays. It is also useful to fabricate a highly resonant gyroscope, which is immune to environmental noise.
The San Andreas fault experiment. [gross tectonic plates relative velocity
Smith, D. E.; Vonbun, F. O.
1973-01-01
A plan was developed during 1971 to determine gross tectonic plate motions along the San Andreas Fault System in California. Knowledge of the gross motion along the total fault system is an essential component in the construction of realistic deformation models of fault regions. Such mathematical models will be used in the future for studies which will eventually lead to prediction of major earthquakes. The main purpose of the experiment described is the determination of the relative velocity of the North American and the Pacific Plates. This motion being so extremely small, cannot be measured directly but can be deduced from distance measurements between points on opposite sites of the plate boundary taken over a number of years.
Numerical analysis of two experiments related to thermal fatigue
Bieder, Ulrich; Errante, Paolo [DEN-STMF, Commissariat a l' Energie Atomique et aux Energies Alternatives, Universite Paris-Saclay, Gif-sur-Yvette (France)
2017-06-15
Jets in cross flow are of fundamental industrial importance and play an important role in validating turbulence models. Two jet configurations related to thermal fatigue phenomena are investigated: • T-junction of circular tubes where a heated jet discharges into a cold main flow and • Rectangular jet marked by a scalar discharging into a main flow in a rectangular channel. The T-junction configuration is a classical test case for thermal fatigue phenomena. The Vattenfall T-junction experiment was already subject of an OECD/NEA benchmark. A LES modelling and calculation strategy is developed and validated on this data. The rectangular-jet configuration is important for basic physical understanding and modelling and has been analyzed experimentally at CEA. The experimental work was focused on turbulent mixing between a slightly heated rectangular jet which is injected perpendicularly into the cold main flow of a rectangular channel. These experiments are analyzed for the first time with LES. The overall results show a good agreement between the experimental data and the CFD calculation. Mean values of velocity and temperature are well captured by both RANS calculation and LES. The range of critical frequencies and their amplitudes, however, are only captured by LES.
Medication Errors In Relation To Education & Years of Nursing Experience
Shweta D Singh
2012-06-01
Full Text Available Medication error is defined as any preventable event that might cause or lead to an inappropriate use orharming of the patient. The purpose of this study was to determine the relationship between the level ofeducation and medication errors; years of work experience and medication errors. With a betterunderstanding of these relationships, nursing professionals can learn what characteristics tend to make anurse prone to medication errors and can develop methods and procedures to reduce incidence. Thesurvey was conducted in 6 hospitals in Anand city. Approval had been obtained from the hospitalswhere the study was to be conducted. The survey form was divided into 5 different sections. Eachsection comprises of minimum 3 questions which relates to their basic information and their perceptionstowards medication error. The results of the study suggested that there is a direct relationship betweeneducation/experiences and medication errors. The study showed that medication error occurs due to lackof qualified nursing staff. The results showed that medication error were reported due to increaseworkload on nurses because of lack of number of nurses in hospitals.
Lived experience of economic and political trends related to globalization.
Cushon, Jennifer A; Muhajarine, Nazeem; Labonte, Ronald
2010-01-01
A multi-method case study examined how the economic and political processes of globalization have influenced the determinants of health among low-income children in Saskatoon, Saskatchewan, Canada. This paper presents the results from the qualitative interview component of the case study. The purpose of the interviews was to uncover the lived experience of low-income families and their children in Saskatoon with regards to political and economic trends related to globalization, an important addition to the usual globalization and health research that relies primarily on cross-country regressions in which the personal impacts remain hidden. In-depth phenomenological interviews with 26 low-income parents of young children (aged zero to five) who were residents of Saskatoon. A combination of volunteer and criterion sampling was used. Interview questions were open-ended and based upon an analytical framework. Analysis proceeded through immersion in the data, a process of open coding, and finally through a process of selective coding. The larger case study and interviews indicate that globalization has largely not been benefiting low-income parents with young children. Low-income families with young children were struggling to survive, despite the tremendous economic growth occurring in Saskatchewan and Saskatoon at the time of the interviews. This often led to participants expressing a sense of helplessness, despair, isolation, and/or anger. Respondents' experiences suggest that globalization-related changes in social conditions and public policies and programs have great potential to negatively affect family health through either psychosocial effects in individuals and/or decreased levels of social cohesion in the community.
Error analysis and compensation research of scale factor for MEMS gyroscope
Liu, Chang-zheng; Wang, Xiangjun; Tang, Qi-jian
2014-11-01
In dynamic condition, scale factor has been one of the main errors for MEMS (micro electromechanical system) gyroscopes. This paper, based on one kind of gyroscope in the airborne optoelectronic pod, studies the variation law of the scale factor and its compensation under different environment temperature and operating speed, and then puts forward to the method of combination of ambient temperature and actual angular velocity when compensating the MEMS gyroscope's scale factor error. Test result demonstrates that the scale factor error can be effectively suppressed, and compared with compensation method only based on temperature or angular velocity separately, this new method is easy practical and presents better performance.
Large-area fiber-optic gyroscope on a multiplexed fiber network.
Clivati, C; Calonico, D; Costanzo, G A; Mura, A; Pizzocaro, M; Levi, F
2013-04-01
We describe a fiber-optic gyroscope based on the Sagnac effect, realized on a multiplexed telecom fiber network. Our loop encloses an area of 20 km² and coexists with Internet data traffic. This Sagnac interferometer is capable of detecting signals that are larger than 10(-8) (rad/s)/√Hz, thus approaching ring laser gyroscopes without using a narrow-linewidth laser or sophisticated optics. The proposed gyroscope could be useful for seismic applications, opening new possibilities for this kind of optical fiber sensor.
Dance experience sculpts aesthetic perception and related brain circuits.
Kirsch, Louise P; Dawson, Kelvin; Cross, Emily S
2015-03-01
Previous research on aesthetic preferences demonstrates that people are more likely to judge a stimulus as pleasing if it is familiar. Although general familiarity and liking are related, it is less clear how motor familiarity, or embodiment, relates to a viewer's aesthetic appraisal. This study directly compared how learning to embody an action impacts the neural response when watching and aesthetically evaluating the same action. Twenty-two participants trained for 4 days on dance sequences. Each day they physically rehearsed one set of sequences, passively watched a second set, listened to the music of a third set, and a fourth set remained untrained. Functional MRI was obtained prior to and immediately following the training period, as were affective and physical ability ratings for each dance sequence. This approach enabled precise comparison of self-report methods of embodiment with nonbiased, empirical measures of action performance. Results suggest that after experience, participants most enjoy watching those dance sequences they danced or observed. Moreover, brain regions involved in mediating the aesthetic response shift from subcortical regions associated with dopaminergic reward processing to posterior temporal regions involved in processing multisensory integration, emotion, and biological motion.
Theoretical z -pinch scaling relations for thermonuclear-fusion experiments.
Stygar, W A; Cuneo, M E; Vesey, R A; Ives, H C; Mazarakis, M G; Chandler, G A; Fehl, D L; Leeper, R J; Matzen, M K; McDaniel, D H; McGurn, J S; McKenney, J L; Muron, D J; Olson, C L; Porter, J L; Ramirez, J J; Seamen, J F; Speas, C S; Spielman, R B; Struve, K W; Torres, J A; Waisman, E M; Wagoner, T C; Gilliland, T L
2005-08-01
We have developed wire-array z -pinch scaling relations for plasma-physics and inertial-confinement-fusion (ICF) experiments. The relations can be applied to the design of z -pinch accelerators for high-fusion-yield (approximately 0.4 GJ/shot) and inertial-fusion-energy (approximately 3 GJ/shot) research. We find that (delta(a)/delta(RT)) proportional (m/l)1/4 (Rgamma)(-1/2), where delta(a) is the imploding-sheath thickness of a wire-ablation-dominated pinch, delta(RT) is the sheath thickness of a Rayleigh-Taylor-dominated pinch, m is the total wire-array mass, l is the axial length of the array, R is the initial array radius, and gamma is a dimensionless functional of the shape of the current pulse that drives the pinch implosion. When the product Rgamma is held constant the sheath thickness is, at sufficiently large values of m/l, determined primarily by wire ablation. For an ablation-dominated pinch, we estimate that the peak radiated x-ray power P(r) proportional (I/tau(i))(3/2)Rlphigamma, where I is the peak pinch current, tau(i) is the pinch implosion time, and phi is a dimensionless functional of the current-pulse shape. This scaling relation is consistent with experiment when 13 MA tau(i) tau(i)P(r)(7/9 ))(-1), where P(a) is the peak accelerator power. The pinch current and accelerator power required to achieve a given value of P(r) are proportional to tau(i), and the requisite accelerator energy E(a) is proportional to tau2(i). These results suggest that the performance of an ablation-dominated pinch, and the efficiency of a coupled pinch-accelerator system, can be improved substantially by decreasing the implosion time tau(i). For an accelerator coupled to a double-pinch-driven hohlraum that drives the implosion of an ICF fuel capsule, we find that the accelerator power and energy required to achieve high-yield fusion scale as tau(i)0.36 and tau(i)1.36, respectively. Thus the accelerator requirements decrease as the implosion time is decreased. However
Video games and collaborative learning. Experiences related to Primary Education
Marta MARTÍN DEL POZO
2015-07-01
Full Text Available Video games are not only a way of entertainment, but also they can be used for learning as an educational resource. In that sense, the aim of this article is to perform a systematic review about experiences and research about the use of video games in the stage of Primary Education (that is to say, with children between 6 and 12 years old, but, in particularly, experiences with a collaborative learning approach and, also, with a pre and post achievement or learning test to show if students made learning gains. In order to fulfill the main objective, the article will be divided in five key sections showing the main aspects related to this topic: video games in education, collaborative learning, the methodology for the systematic review, results and conclusions about the results. As a result, a total of 8 studies met the inclusion criteria and they were selected for the analysis. In that sense, we show that video games can be used in a collaborative learning approach, in contrast to the common idea that video games generate isolate persons, above all children and, furthermore, in general, students improve their learning achievement. In conclusion, video games can be a good resource for learning process and, for example, they can be used in a collaborative learning approach but it is necessary more information about that because of the limits we show at the end of the article, like, for example, more studies are required with pre and post achievement tests and using experimental and control groups.
Disc resonator gyroscope fabrication process requiring no bonding alignment
Shcheglov, Kirill V. (Inventor)
2010-01-01
A method of fabricating a resonant vibratory sensor, such as a disc resonator gyro. A silicon baseplate wafer for a disc resonator gyro is provided with one or more locating marks. The disc resonator gyro is fabricated by bonding a blank resonator wafer, such as an SOI wafer, to the fabricated baseplate, and fabricating the resonator structure according to a pattern based at least in part upon the location of the at least one locating mark of the fabricated baseplate. MEMS-based processing is used for the fabrication processing. In some embodiments, the locating mark is visualized using optical and/or infrared viewing methods. A disc resonator gyroscope manufactured according to these methods is described.
Role of entanglement in calibrating optical quantum gyroscopes
Kok, Pieter; Dunningham, Jacob; Ralph, Jason F.
2017-01-01
We consider the calibration of an optical quantum gyroscope by modeling two Sagnac interferometers, mounted approximately at right angles to each other. Reliable operation requires that we know the angle between the interferometers with high precision, and we show that a procedure akin to multiposition testing in inertial navigation systems can be generalized to the case of quantum interferometry. We find that while entanglement is a key resource within an individual Sagnac interferometer, its presence between the interferometers is a far more complicated story. The optimum level of entanglement depends strongly on the sought parameter values, and small but significant improvements may be gained from choosing states with the optimal amount of entanglement between the interferometers.
Asymmetric coherent transmission for single particle diode and gyroscope
Yang, S; Sun, C P
2009-01-01
We study the single particle scattering process in a coherent multi-site system consisting of a tight-binding ring threaded by an Aharonov-Bohm flux and several attaching leads. The asymmetric behavior of scattering matrix is discovered analytically in the framework of both Bethe Ansatz and Green's function formalism. It is found that, under certain conditions, a three-site electronic system can behave analogous to a perfect semiconductor diode where current flows only in one direction. The general result is also valid for a neutral particle system since the effective magnetic flux may be implemented by a globe rotation. This observation means that the three-site system can serve as an orientation measuring gyroscope due to the approximate linear dependence of the current difference of two output leads on the rotational angular velocity.
SIMULASI FILTER KALMAN UNTUK ESTIMASI SUDUT DENGAN MENGGUNAKAN SENSOR GYROSCOPE
Wahyudi Wahyudi
2012-02-01
Full Text Available The Kalman filter is a recursive solution to the process linear filtering problem that can remove the noisefrom signal and then the information can useful. The process that use Kalman filter must be approximatedas two equations of linear system, state equation and output equation. Computation of Kalman filter isminimizes the mean of the square error. This paper explore the basic consepts of the Kalman filteralgorithm and simulate its to filter data of gyroscope to get a rotation. The measurement noise covariancedetermines how much information from the sample is used. If measurement noise covariance is high showthat the measurement isn’t very accurate. The process noise covariance contributes to the overalluncertainty of the estimate as it is added to the error covariance matrix in each time step. If the errorcovariance matrix is small the Kalman filter incorporates a lot less of the measurement into estimate ofrotation.
Digitalization optical open loop test system for fiber optic gyroscope
ZHANG Deng-wei; SHU Xiao-wu; MU Xu-dong; LIU Cheng
2006-01-01
In order to receive and process the open loop signal from fiber optic gyroscopes speedily,stably and expediently,and to realize the amity interface between human and machine,a digital system that can convert GPIB (general purpose interface bus ) parallel bus into Universal Serial Bus is developed.All the interface functions of GP1B and the hardware system are realized through FPGA.With a digital sampling and processing system designed with VC++ in Windows platform,the real-time controlling procedure,high-speed receiving and sending data can be carried out,and the results can be displayed too.So the design of the system is flexible,the reliability and the stability are improved,error rate is no more than 10-11,the highest bit rate is 8 MB/s and the open loop detection system for optic fiber gyros achieves standardization and complete digitalization simultaneously.
Model of a laser gyroscope with frequency dithering
Sakharov, V. K.
2016-06-01
The model of a laser gyroscope (LG) with frequency dithering is described by a system of recurrent equations for the electric fields of counterpropagating waves. The phenomenon of frequency locking is taken into account in the form of the wave coupling through backward scattering; the frequency bias factor is the controlled phase nonreciprocity. The character of the output signal is considered, which corresponds to two types of frequency dithering, namely, sinusoidal and in the form of meander that are produced by various methods, including intracavity phase modulation. Results of calculation of a frequency characteristic of the LG are presented as functions of frequency dithering, rotational velocity and LG parameters. It is shown that the method of processing an output signal by measuring the time interval between intensity oscillations has an advantage due to the absence of so-called dynamic lock-in zones in the output characteristic.
Regional Community and International Relations: the Volgograd Region Experience
Danakari Richard A.
2016-06-01
Full Text Available The article deals with the complex and controversial problems of the new regional communities’ formation and the impact of the interethnic relations sphere on them. The author notes that the processes of interaction between representatives of different cultures and civilizations, ethnic groups and religions have become increasingly controversial and tense in the context of continuous social dynamics. Similarly to the Russian society as a whole, regional communities are in a state of transitivity. They get transformed, they acquire new qualities such as multicasting and heterogeneity, multi-ethnicity and multi-confessionalism, fragmentarity and multiculturality. This fact increases the risks and uncertainties, problematizes future prospects. National non-governmental organizations are increasingly positioning themselves as civil society institutions at the present stage of social development at the regional level. They perform a difficult dual task: on the one hand, they ensure the preservation and development of history, native language, culture, ethnic traditions, and on the other hand, they work on the integration, on the common identity and the Russian nation formation. On the territory of the Volgograd region, largely due to the active cooperation of regional authorities and local authorities with national public associations, international and inter-confessional relations are stable. The basis of such activity is respect for history, native language, culture, tradition, religion, national dignity of all people in the region, regardless of their belonging to a certain ethnic group or religion. Over two decades of accumulated considerable experience of joint inter-ethnic dialogue and cooperation, provided tolerance and peace, harmony and mutual understanding between people of different ethnicities and religions in the country.
Optical system components for navigation grade fiber optic gyroscopes
Heimann, Marcus; Liesegang, Maximilian; Arndt-Staufenbiel, Norbert; Schröder, Henning; Lang, Klaus-Dieter
2013-10-01
Interferometric fiber optic gyroscopes belong to the class of inertial sensors. Due to their high accuracy they are used for absolute position and rotation measurement in manned/unmanned vehicles, e.g. submarines, ground vehicles, aircraft or satellites. The important system components are the light source, the electro optical phase modulator, the optical fiber coil and the photodetector. This paper is focused on approaches to realize a stable light source and fiber coil. Superluminescent diode and erbium doped fiber laser were studied to realize an accurate and stable light source. Therefor the influence of the polarization grade of the source and the effects due to back reflections to the source were studied. During operation thermal working conditions severely affect accuracy and stability of the optical fiber coil, which is the sensor element. Thermal gradients that are applied to the fiber coil have large negative effects on the achievable system accuracy of the optic gyroscope. Therefore a way of calculating and compensating the rotation rate error of a fiber coil due to thermal change is introduced. A simplified 3 dimensional FEM of a quadrupole wound fiber coil is used to determine the build-up of thermal fields in the polarization maintaining fiber due to outside heating sources. The rotation rate error due to these sources is then calculated and compared to measurement data. A simple regression model is used to compensate the rotation rate error with temperature measurement at the outside of the fiber coil. To realize a compact and robust optical package for some of the relevant optical system components an approach based on ion exchanged waveguides in thin glass was developed. This waveguides are used to realize 1x2 and 1x4 splitter with fiber coupling interface or direct photodiode coupling.
Ahrens, Markus; Kucera, Ladislav
1996-01-01
For flywheel rotors or other rotors with significant ratios of moments of inertia, the influence of gyroscopic effects has to be considered. While conservative or damped systems remain stable even under gyroscopic effects, magnetically suspended rotors can be destabilized with increasing rotational speed. The influence of gyroscopic effects on the stability and behavior of a magnetic bearing system is analyzed. The analysis is carried out with a rigid body model for the rotor and a nonlinear model for the magnetic bearing and its amplifier. Cross feedback control can compensate gyroscopic effects. This compensation leads to better system performance and can avoid instability. Furthermore, the implementation of this compensation is simple. The main structure of a decentralized controller can still be used. It has only to be expanded by the cross feedback path.
Li, Rongsheng (Inventor); Kurland, Jeffrey A. (Inventor); Dawson, Alec M. (Inventor); Wu, Yeong-Wei A. (Inventor); Uetrecht, David S. (Inventor)
2004-01-01
Methods and structures are provided that enhance attitude control during gyroscope substitutions by insuring that a spacecraft's attitude control system does not drive its absolute-attitude sensors out of their capture ranges. In a method embodiment, an operational process-noise covariance Q of a Kalman filter is temporarily replaced with a substantially greater interim process-noise covariance Q. This replacement increases the weight given to the most recent attitude measurements and hastens the reduction of attitude errors and gyroscope bias errors. The error effect of the substituted gyroscopes is reduced and the absolute-attitude sensors are not driven out of their capture range. In another method embodiment, this replacement is preceded by the temporary replacement of an operational measurement-noise variance R with a substantially larger interim measurement-noise variance R to reduce transients during the gyroscope substitutions.
Analysis and Design of a 3rd Order Velocity-Controlled Closed-Loop for MEMS Vibratory Gyroscopes
Ji-wei Jiao
2013-09-01
Full Text Available The time-average method currently available is limited to analyzing the specific performance of the automatic gain control-proportional and integral (AGC-PI based velocity-controlled closed-loop in a micro-electro-mechanical systems (MEMS vibratory gyroscope, since it is hard to solve nonlinear functions in the time domain when the control loop reaches to 3rd order. In this paper, we propose a linearization design approach to overcome this limitation by establishing a 3rd order linear model of the control loop and transferring the analysis to the frequency domain. Order reduction is applied on the built linear model’s transfer function by constructing a zero-pole doublet, and therefore mathematical expression of each control loop’s performance specification is obtained. Then an optimization methodology is summarized, which reveals that a robust, stable and swift control loop can be achieved by carefully selecting the system parameters following a priority order. Closed-loop drive circuits are designed and implemented using 0.35 μm complementary metal oxide semiconductor (CMOS process, and experiments carried out on a gyroscope prototype verify the optimization methodology that an optimized stability of the control loop can be achieved by constructing the zero-pole doublet, and disturbance rejection capability (D.R.C of the control loop can be improved by increasing the integral term.
Analysis and design of a 3rd order velocity-controlled closed-loop for MEMS vibratory gyroscopes.
Wu, Huan-ming; Yang, Hai-gang; Yin, Tao; Jiao, Ji-wei
2013-09-18
The time-average method currently available is limited to analyzing the specific performance of the automatic gain control-proportional and integral (AGC-PI) based velocity-controlled closed-loop in a micro-electro-mechanical systems (MEMS) vibratory gyroscope, since it is hard to solve nonlinear functions in the time domain when the control loop reaches to 3rd order. In this paper, we propose a linearization design approach to overcome this limitation by establishing a 3rd order linear model of the control loop and transferring the analysis to the frequency domain. Order reduction is applied on the built linear model's transfer function by constructing a zero-pole doublet, and therefore mathematical expression of each control loop's performance specification is obtained. Then an optimization methodology is summarized, which reveals that a robust, stable and swift control loop can be achieved by carefully selecting the system parameters following a priority order. Closed-loop drive circuits are designed and implemented using 0.35 μm complementary metal oxide semiconductor (CMOS) process, and experiments carried out on a gyroscope prototype verify the optimization methodology that an optimized stability of the control loop can be achieved by constructing the zero-pole doublet, and disturbance rejection capability (D.R.C) of the control loop can be improved by increasing the integral term.
Adaptive tracking control of an MEMS gyroscope with H-infinity performance
无
2011-01-01
Microelectromechanical systems (MEMSs) pose unique measurement and control problems compared with conventional ones because of their small size,low cost,and low power consumption.The vibrating gyroscope is one of those MEMS devices that have significant potential in many industry applications.When the MEMS gyroscope system is considered simultaneously with the coupling terms,the exogenous disturbances and the parameter variations,the controller design of this system becomes very challenging.This paper inves...
Study of a MEMS Vibratory Gyroscope Using Adaptive Iterative Learning Control
Xiaochun Lu; Juntao Fei
2014-01-01
This paper proposes a framework, namely adaptive iterative learning control (AILC), which is used in the control of a microelectromechanical system (MEMS) gyroscope, to realize high-precision trajectory tracking control. According to the characteristics of the MEMS gyroscope’s model, the proposed AILC algorithm includes an adaptive law of parametric estimation and an iteration control law, which is updated in the iterative domain without any prior knowledge of MEMS gyroscopes. The convergence...
Noise Reduction of MEMS Gyroscope Based on Direct Modeling for an Angular Rate Signal
Liang Xue; Chengyu Jiang; Lixin Wang; Jieyu Liu; Weizheng Yuan
2015-01-01
In this paper, a novel approach for processing the outputs signal of the microelectromechanical systems (MEMS) gyroscopes was presented to reduce the bias drift and noise. The principle for the noise reduction was presented, and an optimal Kalman filter (KF) was designed by a steady-state filter gain obtained from the analysis of KF observability. In particular, the true angular rate signal was directly modeled to obtain an optimal estimate and make a self-compensation for the gyroscope witho...
1980-06-13
tue outer ring of Cardan joints for the suspension of this gyroscope can be attached to a stabilizing platform. Let the intrinsic Kinetic momant of...type of stabilization. The plane of the platform P, which is connected with the object by a three-dimensional cardan suspension (not shown in the figure...of the outer ring of this DOC = 0925 PAGE 15 gyroscope’s cardan suspension are arranged on the stabilized platform so that the axis itself lies in tn
Analysis of the gyroscopic stabilization of a system of rigid bodies
Kliem, Wolfhard; Seyranian, Alexander P.
1997-01-01
We study the gyroscopic stability of a three-body system. A new method of finding stability regions, based on mechanism and criteria for gyroscopic stabilization, is presented. Of particular interest in this connection is the theory of interaction of eigenvalues. This leads to a complete 3......-dimensional analysis, which shows the regions of stability, divergence, and flutter of a simple model of a rotating spaceship....
The Natural Frequency Analysis of Gyroscope%陀螺仪固有频率分析
朱鹏华; 荆建平; 白晓林
2012-01-01
Micro gyroscopes have very important application in the aircraft,missile and ships inertial navigation system.The natural frequency of the gyroscope is analyzed according to the principle and structure of the gyroscopes.Since the test of the missile gyroscope is not easy,the software ABAQUS is used to build the model of the gyroscope and analyzed the theoretic natural frequency of the gyroscope,also experimental test is done to measure the natural frequency of the gyroscope using the LMS device and software.The results show that the theoretical analysis and the experimental results are basically the same,which also indicates the finite model of gyroscope is effective.%微机械陀螺仪在飞机、导弹、轮船的惯性导航系统中具有重要应用。依据陀螺仪的结构和工作原理,对该微机械陀螺仪的固有频率进行了分析。由于单独的陀螺仪实验测试比较困难,利用ABAQUS有限元分析软件建立了陀螺仪的有限元模型,计算出了其各阶模态,并与陀螺仪试验模态分析进行了对比。结果显示：有限元分析结果和实验结果基本一致,表明所建立的陀螺仪有限元模型是正确的。
Oscillation control algorithms for resonant sensors with applications to vibratory gyroscopes.
Park, Sungsu; Tan, Chin-Woo; Kim, Haedong; Hong, Sung Kyung
2009-01-01
We present two oscillation control algorithms for resonant sensors such as vibratory gyroscopes. One control algorithm tracks the resonant frequency of the resonator and the other algorithm tunes it to the specified resonant frequency by altering the resonator dynamics. Both algorithms maintain the specified amplitude of oscillations. The stability of each of the control systems is analyzed using the averaging method, and quantitative guidelines are given for selecting the control gains needed to achieve stability. The effects of displacement measurement noise on the accuracy of tracking and estimation of the resonant frequency are also analyzed. The proposed control algorithms are applied to two important problems in a vibratory gyroscope. The first is the leading-following resonator problem in the drive axis of MEMS dual-mass vibratory gyroscope where there is no mechanical linkage between the two proof-masses and the second is the on-line modal frequency matching problem in a general vibratory gyroscope. Simulation results demonstrate that the proposed control algorithms are effective. They ensure the proof-masses to oscillate in an anti-phase manner with the same resonant frequency and oscillation amplitude in a dual-mass gyroscope, and two modal frequencies to match in a general vibratory gyroscope.
On Bandwidth Characteristics of Tuning Fork Micro-Gyroscope with Mechanically Coupled Sense Mode
Yunfang Ni
2014-07-01
Full Text Available The bandwidth characteristics of a tuning fork micro-gyroscope with mechanically coupled sense mode were investigated in this paper to provide some references for mechanical bandwidth design. The concept of sense mode mechanical coupling is introduced first. Theoretical frequency response analyses were then carried out on the mechanical part of the gyroscope. Equations representing the relationships between the differential output signal and the frequency of the input angular rate were deduced in full frequency range and further simplified in low frequency range. Based on these equations, bandwidth characteristics under ideal and non-ideal conditions are discussed. Analytical results show that under ideal conditions, the bandwidth characteristics of a tuning fork micro-gyroscope are similar to those of a single mass micro-gyroscope, but under non-ideal conditions, especially when sense mass and/or stiffness are asymmetric, the bandwidth characteristics would be quite different because the in-phase mode would participate in the anti-phase vibration response. Experimental verifications were carried out on two micro-gyroscope prototypes designed in our laboratory. The deduced equations and analytical results can be used in guiding the mechanical bandwidth design of tuning fork micro-gyroscopes with mechanically coupled sense mode.
On bandwidth characteristics of tuning fork micro-gyroscope with mechanically coupled sense mode.
Ni, Yunfang; Li, Hongsheng; Huang, Libin; Ding, Xukai; Wang, Haipeng
2014-01-01
The bandwidth characteristics of a tuning fork micro-gyroscope with mechanically coupled sense mode were investigated in this paper to provide some references for mechanical bandwidth design. The concept of sense mode mechanical coupling is introduced first. Theoretical frequency response analyses were then carried out on the mechanical part of the gyroscope. Equations representing the relationships between the differential output signal and the frequency of the input angular rate were deduced in full frequency range and further simplified in low frequency range. Based on these equations, bandwidth characteristics under ideal and non-ideal conditions are discussed. Analytical results show that under ideal conditions, the bandwidth characteristics of a tuning fork micro-gyroscope are similar to those of a single mass micro-gyroscope, but under non-ideal conditions, especially when sense mass and/or stiffness are asymmetric, the bandwidth characteristics would be quite different because the in-phase mode would participate in the anti-phase vibration response. Experimental verifications were carried out on two micro-gyroscope prototypes designed in our laboratory. The deduced equations and analytical results can be used in guiding the mechanical bandwidth design of tuning fork micro-gyroscopes with mechanically coupled sense mode.
Oscillation Control Algorithms for Resonant Sensors with Applications to Vibratory Gyroscopes
Sung Kyung Hong
2009-07-01
Full Text Available We present two oscillation control algorithms for resonant sensors such as vibratory gyroscopes. One control algorithm tracks the resonant frequency of the resonator and the other algorithm tunes it to the specified resonant frequency by altering the resonator dynamics. Both algorithms maintain the specified amplitude of oscillations. The stability of each of the control systems is analyzed using the averaging method, and quantitative guidelines are given for selecting the control gains needed to achieve stability. The effects of displacement measurement noise on the accuracy of tracking and estimation of the resonant frequency are also analyzed. The proposed control algorithms are applied to two important problems in a vibratory gyroscope. The first is the leading-following resonator problem in the drive axis of MEMS dual-mass vibratory gyroscope where there is no mechanical linkage between the two proof-masses and the second is the on-line modal frequency matching problem in a general vibratory gyroscope. Simulation results demonstrate that the proposed control algorithms are effective. They ensure the proof-masses to oscillate in an anti-phase manner with the same resonant frequency and oscillation amplitude in a dual-mass gyroscope, and two modal frequencies to match in a general vibratory gyroscope.
Relating triggering processes in lab experiments with earthquakes.
Baro Urbea, J.; Davidsen, J.; Kwiatek, G.; Charalampidou, E. M.; Goebel, T.; Stanchits, S. A.; Vives, E.; Dresen, G.
2016-12-01
Statistical relations such as Gutenberg-Richter's, Omori-Utsu's and the productivity of aftershocks were first observed in seismology, but are also common to other physical phenomena exhibiting avalanche dynamics such as solar flares, rock fracture, structural phase transitions and even stock market transactions. All these examples exhibit spatio-temporal correlations that can be explained as triggering processes: Instead of being activated as a response to external driving or fluctuations, some events are consequence of previous activity. Although different plausible explanations have been suggested in each system, the ubiquity of such statistical laws remains unknown. However, the case of rock fracture may exhibit a physical connection with seismology. It has been suggested that some features of seismology have a microscopic origin and are reproducible over a vast range of scales. This hypothesis has motivated mechanical experiments to generate artificial catalogues of earthquakes at a laboratory scale -so called labquakes- and under controlled conditions. Microscopic fractures in lab tests release elastic waves that are recorded as ultrasonic (kHz-MHz) acoustic emission (AE) events by means of piezoelectric transducers. Here, we analyse the statistics of labquakes recorded during the failure of small samples of natural rocks and artificial porous materials under different controlled compression regimes. Temporal and spatio-temporal correlations are identified in certain cases. Specifically, we distinguish between the background and triggered events, revealing some differences in the statistical properties. We fit the data to statistical models of seismicity. As a particular case, we explore the branching process approach simplified in the Epidemic Type Aftershock Sequence (ETAS) model. We evaluate the empirical spatio-temporal kernel of the model and investigate the physical origins of triggering. Our analysis of the focal mechanisms implies that the occurrence
Piecewise compensation for the nonlinear error of fiber-optic gyroscope scale factor
Zhang, Yonggang; Wu, Xunfeng; Yuan, Shun; Wu, Lei
2013-08-01
Fiber-Optic Gyroscope (FOG) scale factor nonlinear error will result in errors in Strapdown Inertial Navigation System (SINS). In order to reduce nonlinear error of FOG scale factor in SINS, a compensation method is proposed in this paper based on curve piecewise fitting of FOG output. Firstly, reasons which can result in FOG scale factor error are introduced and the definition of nonlinear degree is provided. Then we introduce the method to divide the output range of FOG into several small pieces, and curve fitting is performed in each output range of FOG to obtain scale factor parameter. Different scale factor parameters of FOG are used in different pieces to improve FOG output precision. These parameters are identified by using three-axis turntable, and nonlinear error of FOG scale factor can be reduced. Finally, three-axis swing experiment of SINS verifies that the proposed method can reduce attitude output errors of SINS by compensating the nonlinear error of FOG scale factor and improve the precision of navigation. The results of experiments also demonstrate that the compensation scheme is easy to implement. It can effectively compensate the nonlinear error of FOG scale factor with slightly increased computation complexity. This method can be used in inertial technology based on FOG to improve precision.
Li, Min; Huang, Xiaokai; Jin, Jing; Chen, Yunxia; Kang, Rui
Noise failure, particularly due to random walk error (RWE) degradation behavior, is one of the critical failure modes for fiber-optic gyroscopes (FOGs) in space applications. In this paper, firstly, the analytical model of RWE is presented and the affected parameters are listed according to the gamma irradiation damage mechanism. In addition, the influence of temperature is also included. The deterioration of affected parameters is determined through a 60Co radiation experiment on optic and optoelectronic components. Based on the parameters’ deterioration range and assumed distribution properties, their importance to the noise failure is calculated through the Sobol method, a global sensitivity analysis method. In the computation steps, the Latin Hyper Sampling (LHS) based Monte-Carlo numerical simulation technique is adopted. It is determined from calculation results that the detected light power (DLP) is the noise failure characteristic which is the most sensitive parameter in the space environment. Finally, another 60Co radiation experiment with the same conditions is performed on a superluminescent diode (SLD) FOG. The original noise degradation behavior is compared to the simulated RWE, calculated according to DLP, and the result shows that they follow trend almost identical. This supports the conclusion that DLP is the most sensitive noise failure characteristic for SLD-based FOGs.
Mechanical-Thermal Noise in Drive-Mode of a Silicon Micro-Gyroscope
Bailing Zhou
2009-05-01
Full Text Available A new closed-loop drive scheme which decouples the phase and the gain of the closed-loop driving system was designed in a Silicon Micro-Gyroscope (SMG. We deduce the system model of closed-loop driving and use stochastic averaging to obtain an approximate “slow” system that clarifies the effect of thermal noise. The effects of mechanical-thermal noise on the driving performance of the SMG, including the noise spectral density of the driving amplitude and frequency, are derived. By calculating and comparing the noise amplitude due to thermal noise both in the opened-loop driving and in the closed-loop driving, we find that the closed-loop driving does not reduce the RMS noise amplitude. We observe that the RMS noise frequency can be reduced by increasing the quality factor and the drive amplitude in the closed-loop driving system. The experiment and simulation validate the feasibility of closed-loop driving and confirm the validity of the averaged equation and its stablility criterion. The experiment and simulation results indicate the electrical noise of closed-loop driving circuitry is bigger than the mechanical-thermal noise and as the driving mass decreases, the mechanical-thermal noise may get bigger than the electrical noise of the closed-loop driving circuitry.
Prior Computer-Related Experiences and Hypermedia Metacognition.
Reed, W. Michael; Giessler, Steven F.
1995-01-01
Discusses the relationship between prior computer experiences and the linear or nonlinear steps students choose when working with hypermedia environments and time spent on task (based on a study of graduate students). Experience with content-area software, word processing, databases, spreadsheets, programming, hypermedia, and authoring are…
Improved Kennedy-Thorndike experiment to test special relativity
Hils, Dieter; Hall, J. L.
1990-01-01
A modern version of the Kennedy-Thorndike experiment was carried out by searching for sidereal variations between the frequency of a laser locked to an I2 reference line and a laser locked to the resonance frequency of a highly stable cavity. No variations were found at the level of 2 x 10 to the -12th. This represents a 300-fold improvement over the original Kennedy-Thorndike experiment and allows the Lorentz transformations to be deduced entirely from experiment at an accuracy level of 70 ppm.
Costa, L Filipe O; Herdeiro, Carlos A R, E-mail: filipezola@fc.up.p, E-mail: crherdei@fc.up.p [Centro de Fisica do Porto, Faculdade de Ciencias Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)
2010-05-01
We compare the covariant expression of the electromagnetic force exerted on a magnetic dipole with Papapetrou's equation for the gravitational force exerted on a spinning test particle. We show that if Pirani's supplementary spin condition holds, there is an exact, covariant, and fully general analogy relating these two forces: both are determined by a contraction of the spin 4-vector with a magnetic-type tidal tensor. Moreover, these tidal tensors obey strikingly analogous equations which are covariant forms for (some of) Maxwell's and Einstein's field equations. These equations allow for an insightful comparison between the two interactions. It is shown that, in the special case that the gyroscope/dipole are 'at rest' and far away from a stationary source, the two forces are similar (in accordance with the results known from linearized theory); but that for generic dynamics key differences arise. In particular we show that the time projection of the force on a dipole is the power transferred to it by Faraday's induction, whereas the fact that the force on a gyroscope is spatial signals the absence of an analogous gravitational effect; that whereas the total work done on a magnetic dipole by a stationary magnetic field is zero, a stationary gravitomagnetic field, by contrast, does work on mass currents, which quantitatively explains the Hawking-Wald spin interaction energy.
Some experiences related to innovation methodologies within the university classroom
Beatriz Amante García
2012-03-01
Full Text Available In this second year of our Journal JOTSE our main challenge is to publish experiences related to innovation methodologies within the university classroom. Thus, allowing for the implementation and/or evaluation of competences throughout students’ learning process and, especially, in the scientific and technological fields. We understand competences as the combination of knowledge, skills and attitudes necessary to perform a task efficiently. Thereby, demonstrating abilities in action and developing them through activities that integrate all these aspects. In the area of higher studies in the scientific and/or technological fields it is rather common that the methodologies developed have a very practical component and, in addition, they are closely linked to the professional career our students are being trained for. Particularly, in the last academic years and at the end of their studies it is when students attend more applied subjects, such as Projects in the case of Engineering Studies that together with the Degree’s Final Project (PFC allow to integrate a wide range of generic or cross-curricular competences and specific ones within the field. These types of subjects have shown to be very efficient to make students become closer to the professional reality that they will face at the end of their studies and where they will have to provide a solution for problematic situations or to meet the needs nowadays society demands. (Dochy et al. (2003, Prince (2004,Prince and Felder (2006 Furthermore, with the incorporation to Bologna process, targeting a more active role of students during their learning process, it is even more relevant that students face real problems from the very beginning of their studies so that they gradually acquire generic competences, which are vital for their training both as individuals and as professionals in our present society. It is within this context that Problem-Based Learning (PBL has proved its usefulness to
翁海诠; 任春华; 张敬栋; 杨佳蒙; 赵巧宏
2011-01-01
Aiming at the disadvantages of micro electro mechanical systems ( MEMS ) gyroscope directional inclinometers in oil and gas well directional measurement, this paper presents a method of decreasing the drift of MEMS gyroscope based on minimum resolution. On the basis of studying the drift characteristics of the MEMS gyroscope output signal, the new method utilizes the sampling difference value to separate valid signal from drift signal in MEMS gyroscope output and estimates the drift with static experiments to suppress the drift of MEMS gyroscope. Experiments show that this method greatly improves the directional accuracy by about 50% ; and also provides a useful reference for estimating and suppressing the drift of other similar sensors.%针对油气井MEMS陀螺定向测斜仪存在的漂移大,精度较低的问题,本文从实际工程应用角度出发,在研究MEMS陀螺仪输出信号漂移特性的基础上,提出了基于最小分辨率的MEMS陀螺漂移抑制方法,利用输出采样的差分值,从MEMS陀螺输出中将传感信号和漂移信号分离,同时通过静态测点对漂移进行估计.实验表明,该方法大幅提高了仪器测量精度,使定向精度提高50％以上,同时该方法为其它类似传感器漂移抑制提供了一种有益的参考.
Special Relativity and the Michelson-Morley Experiment.
Chapman, Bryan R.
1979-01-01
Presents selective and representative evidence relating to the genesis of the theory of special relativity. The evidence seems to defy most of the philosophic preconceptions which many physics teachers appear to have about the nature of physics. (GA)
Velikoseltsev, A A; Luk' yanov, D P [St. Petersburg Electrotechnical University ' ' LETI' ' , St. Petersburg (Russian Federation); Vinogradov, V I [OJSC Tambov factory Elektropribor (Russian Federation); Shreiber, K U [Forschungseinrichtung Satellitengeodaesie, Technosche Universitaet Muenchen, Geodaetisches Observatorium Wettzell, Sackenrieder str. 25, 93444 Bad Koetzting (Germany)
2014-12-31
A brief survey of the history of the invention and development of super-large laser gyroscopes (SLLGs) is presented. The basic results achieved using SLLGs in geodesy, seismology, fundamental physics and other fields are summarised. The concept of SLLG design, specific features of construction and implementation are considered, as well as the prospects of applying the present-day optical technologies to laser gyroscope engineering. The possibilities of using fibre-optical gyroscopes in seismologic studies are analysed and the results of preliminary experimental studies are presented. (laser gyroscopes)
Teachers' literacy-related knowledge and self-perceptions in relation to preparation and experience.
Spear-Swerling, Louise; Brucker, Pamela Owen; Alfano, Michael P
2005-12-01
After rating their own literacy-related knowledge in three areas (knowledge about reading/reading development, phonemic awareness/phonics, and morpheme awareness/structural analysis), graduate teacher-education students completed five tasks intended to measure their actual disciplinary knowledge in these areas. Teachers with high levels of prior background (i.e., course preparation and experience) rated themselves as significantly more knowledgeable than did low-background teachers in all areas; high-background participants also significantly outperformed low-background participants on all tasks. However, even high-background teachers scored well below ceiling on the tasks. Regression analyses indicated that teachers' self-perceptions and knowledge were positively influenced by both level of preparation and teaching experience, although the influences on teachers' knowledge differed by task. Teachers had some accurate perceptions of their own knowledge, especially in the area of phonics. Results suggest that differentiating levels of preparation may be useful in studying teacher knowledge, and also support the notion of a substantial gap between research on reading and teacher preparation in reading.
Experiments in Planetary and Related Sciences and the Space Station
Greeley, Ronald (Editor); Williams, Richard J. (Editor)
1987-01-01
Numerous workshops were held to provide a forum for discussing the full range of possible experiments, their science rationale, and the requirements on the Space Station, should such experiments eventually be flown. During the workshops, subgroups met to discuss areas of common interest. Summaries of each group and abstracts of contributed papers as they developed from a workshop on September 15 to 16, 1986, are included. Topics addressed include: planetary impact experimentation; physics of windblown particles; particle formation and interaction; experimental cosmochemistry in the space station; and an overview of the program to place advanced automation and robotics on the space station.
A Thought Experiment to Distinguish the Kerr Black Hole and Over-spinning Singularities
Chakraborty, Chandrachur; Joshi, Pankaj S
2016-01-01
We propose a thought experiment here to distinguish an over-spinning Kerr singularity from a Kerr black hole, using the gyroscopic precession due to the frame-dragging effect. We show that there is an important characteristic difference in behavior of the gyroscope precession frequency for these objects, which can be used to distinguish one from the other. Specifically, if we lower the gyroscope along the pole of the Kerr black hole, the precession frequency becomes arbitrarily high, blowing up as the event horizon is approached. However, in the case of an over-spinning Kerr singularity, this frequency always remains finite and is fully well-behaved. It turns out that this behavior is intimately related to and governed by the nature of ergoregions in each of these cases. Interestingly, it turns out that in the over-spinning singularity case, the precession frequency ($\\Omega_{LT}$) of the gyro decreases as ($\\Omega_{LT}\\propto r$) after reaching a maximum, in the limit of approach to the singularity. In princ...
THE STABILIZATION SYSTEM ON PAYLOAD BUILT ON A DYNAMICALLY TUNED GYROSCOPE
D. M. Malyutin
2016-01-01
Full Text Available It is now widely distributed systems stabilization based on gyroscopes with three-degree-freedom and based on gyroscopes with ball suspension. The accuracy and resource of operation of such systems requires an increase. The problem of improving the accuracy and increasing the service life of information – measuring systems of stabilization can be solved by using as a sensitive element of a dynamically tuned gyroscope. Today the issue of achieving the potential of the metrological characteristics of information-measuring systems stabilization on dynamically tuned gyroscope is not fully resolved. It requires the development of mathematical models, different from the known, detailed description of the perturbations acting on a device. In addition, it is necessary to develop structures amplifying-transforming paths of the contours stabilization of information-measuring systems of stabilization on dynamically tuned gyroscopes, assuring higher accuracy and noise immunity of the system, what is the purpose of the work. In using the Euler equations obtained a complete mathematical model of functioning system with three motion bases, in detail taking into account the disturbances acting on the device. Considered are the peculiarities of mathematical description of dynamically tuned gyroscope. Dominant frequencies of components noise is identified in the output signal of the gyroscope. The original scheme of the contours stabilization is presented, that help increase the accuracy of stabilization at low frequencies and of providing the absence of systematic drift of the gyrostabilizer from the action of the permanent disturbing moment along the axis of stabilization. The dynamic calculations show the possibility of providing error of stabilization on payload not more than 0,0042 degree.
Two Novel Measurements for the Drive-Mode Resonant Frequency of a Micromachined Vibratory Gyroscope
Ancheng Wang
2013-11-01
Full Text Available To investigate the drive-mode resonance frequency of a micromachined vibratory gyroscope (MVG, one needs to measure it accurately and efficiently. The conventional approach to measure the resonant frequency is by performing a sweep frequency test and spectrum analysis. The method is time-consuming and inconvenient because of the requirements of many test points, a lot of data storage and off-line analyses. In this paper, we propose two novel measurement methods, the search method and track method, respectively. The former is based on the magnitude-frequency characteristics of the drive mode, utilizing a one-dimensional search technique. The latter is based on the phase-frequency characteristics, applying a feedback control loop. Their performances in precision, noise resistivity and efficiency are analyzed through detailed simulations. A test system is implemented based on a field programmable gate array (FPGA and experiments are carried out. By comparing with the common approach, feasibility and superiorities of the proposed methods are validated. In particular, significant efficiency improvements are achieved whereby the conventional frequency method consumes nearly 5,000 s to finish a measurement, while only 5 s is needed for the track method and 1 s for the search method.
Boschmann, Alexander; Nofen, Barbara; Platzner, Marco
2013-01-01
Pattern recognition of myoelectric signals in upper-limb prosthesis control has been subject to intense research for several years. However, few systems have yet been successfully clinically implemented. One possible explanation for this discrepancy is that published reports mostly focus on classification accuracy of myoelectric signals recorded under laboratory conditions as the metric for the system's performance. These data are usually acquired only during the static state of the contraction in a fixed seated position. This supports the test subject in performing repeatable contractions throughout the experiment and generally results in an unrealistically high classification accuracy. In clinical testing however, subjects have to perform various activities of daily living, causing the limb to move in different positions. These variations in limb positions can significantly decrease robustness and usability of myoelectric control systems. Recent reports have shown that the so-called limb position effect can be resolved for the static state of the signal by adding accelerometer data to the feature vector. Including data from the transient state of the signals for classifier training generally significantly increases the classification error so it is mostly not considered in published reports. In this paper, we investigate the classification accuracy of transient EMG data, taking into account the limb position effect. We demonstrate that a classifier trained with features from EMG, accelerometer and gyroscope outperforms classifiers using only EMG or EMG and accelerometer data when classifying transient EMG data.
Two novel measurements for the drive-mode resonant frequency of a micromachined vibratory gyroscope.
Wang, Ancheng; Hu, Xiaoping; Luo, Bing; Jiang, Mingming; He, Xiaofeng; Tang, Kanghua
2013-01-01
To investigate the drive-mode resonance frequency of a micromachined vibratory gyroscope (MVG), one needs to measure it accurately and efficiently. The conventional approach to measure the resonant frequency is by performing a sweep frequency test and spectrum analysis. The method is time-consuming and inconvenient because of the requirements of many test points, a lot of data storage and off-line analyses. In this paper, we propose two novel measurement methods, the search method and track method, respectively. The former is based on the magnitude-frequency characteristics of the drive mode, utilizing a one-dimensional search technique. The latter is based on the phase-frequency characteristics, applying a feedback control loop. Their performances in precision, noise resistivity and efficiency are analyzed through detailed simulations. A test system is implemented based on a field programmable gate array (FPGA) and experiments are carried out. By comparing with the common approach, feasibility and superiorities of the proposed methods are validated. In particular, significant efficiency improvements are achieved whereby the conventional frequency method consumes nearly 5,000 s to finish a measurement, while only 5 s is needed for the track method and 1 s for the search method.
Analysis and Optimization of Dynamic Measurement Precision of Fiber Optic Gyroscope
Hui Li
2013-01-01
Full Text Available In order to improve the dynamic performance of high precision interferometer fiber optic gyroscope (IFOG, the influencing factors of the fast response characteristics are analyzed based on a proposed assistant design setup, and a high dynamic detection method is proposed to suppress the adverse effects of the key influencing factors. The assistant design platform is built by using the virtual instrument technology for IFOG, which can monitor the closed-loop state variables in real time for analyzing the influence of both the optical components and detection circuit on the dynamic performance of IFOG. The analysis results indicate that nonlinearity of optical Sagnac effect, optical parameter uncertainty, dynamic characteristics of internal modules and time delay of signal detection circuit are the major causes of dynamic performance deterioration, which can induce potential system instability in practical control systems. By taking all these factors into consideration, we design a robust control algorithm to realize the high dynamic closed-loop detection of IFOG. Finally, experiments show that the improved 0.01 deg/h high precision IFOG with the proposed control algorithm can achieve fast tracking and good dynamic measurement precision.
Leadership Behaviors and Its Relation with Principals' Management Experience
Mehdinezhad, Vali; Sardarzahi, Zaid
2016-01-01
This paper aims at studying the leadership behaviors reported by principals and observed by teachers and its relationship with management experience of principals. A quantitative method was used in this study. The target population included all principals and teachers of guidance schools and high schools in the Dashtiari District, Iran. A sample…
The challenges and related strategies of planning for wilderness experiences
Kerri Cahill
2012-01-01
Planning is where science, public interests and management of wilderness areas come together. Unfortunately, science and information specifically supporting wilderness experiences, if any exists, is often perceived by managers as subjective, value laden, and hard to defend. This can sometimes lead to the tough decisions about providing high quality wilderness...
Dance experience sculpts aesthetic perception and related brain circuits
Kirsch, L.; Dawson, K.; Cross, E.S.
2015-01-01
Previous research on aesthetic preferences demonstrates that people are more likely to judge a stimulus as pleasing if it is familiar. Although general familiarity and liking are related, it is less clear how motor familiarity, or embodiment, relates to a viewer's aesthetic appraisal. This study dir
Design and Simulation of a New Decoupled Micromachined Gyroscope
Sharaf, Abdelhameed [NCRRT, EAEA, 3 Ahmed Elzomer Street, Nasr City, Cairo (Egypt); STRC, AUC, 113 Kasr El Eini Street, 11215, Cairo (Egypt); Sedky, Sherif [STRC, AUC, 113 Kasr El Eini Street, 11215, Cairo (Egypt); Physics Department, AUC, 113 Kasr El Eini Street, 11215, Cairo (Egypt); Habib, S E-D [Electronics and Communication Department, Faculty of Engineering, Cairo University, 12613, Giza (Egypt)
2006-04-01
This paper reports on a new decoupled micromachined gyroscope. The proposed sensor is a dual mass type, electrostatically driven to primary mode oscillation and senses, capacitively, the output signal. Full decoupling between drive and sense modes minimizes the mechanical crosstalk. Three different designs are introduced in this work. Drive and sense amplitudes, mechanical and electrical sensitivities, quality factors and approximate bandwidths are extracted analytically and the results are confirmed using finite element analysis. The first design shows drive and sense modes resonance frequencies of 4077 Hz and 4081 Hz respectively; with a frequency mismatch lower than 0.1%. The drive and sense capacitance are 0.213 pF and 0.142 pF respectively. The mechanical and electrical sensitivities are 0.011 {mu}m/ ({sup 0}/s) and 2.75 mV/ ({sup 0}/s) respectively. The third design shows significantly improved mechanical and electrical sensitivities of 0.027 {mu}m/ ({sup 0}/s) and 6.85 mV/ ({sup 0}/s) respectively.
Gyroscope Pivot Bearing Dimension and Surface Defect Detection
Xudong Li
2011-03-01
Full Text Available Because of the perceived lack of systematic analysis in illumination system design processes and a lack of criteria for design methods in vision detection a method for the design of a task-oriented illumination system is proposed. After detecting the micro-defects of a gyroscope pivot bearing with a high curvature glabrous surface and analyzing the characteristics of the surface detection and reflection model, a complex illumination system with coaxial and ring lights is proposed. The illumination system is then optimized based on the analysis of illuminance uniformity of target regions by simulation and grey scale uniformity and articulation that are calculated from grey imagery. Currently, in order to apply the Pulse Coupled Neural Network (PCNN method, structural parameters must be tested and adjusted repeatedly. Therefore, this paper proposes the use of a particle swarm optimization (PSO algorithm, in which the maximum between cluster variance rules is used as fitness function with a linearily reduced inertia factor. This algorithm is used to adaptively set PCNN connection coefficients and dynamic threshold, which avoids algorithmic precocity and local oscillations. The proposed method is used for pivot bearing defect image processing. The segmentation results of the maximum entropy and minimum error method and the one described in this paper are compared using buffer region matching, and the experimental results show that the method of this paper is effective.
Gyroscope pivot bearing dimension and surface defect detection.
Ge, Wenqian; Zhao, Huijie; Li, Xudong
2011-01-01
Because of the perceived lack of systematic analysis in illumination system design processes and a lack of criteria for design methods in vision detection a method for the design of a task-oriented illumination system is proposed. After detecting the micro-defects of a gyroscope pivot bearing with a high curvature glabrous surface and analyzing the characteristics of the surface detection and reflection model, a complex illumination system with coaxial and ring lights is proposed. The illumination system is then optimized based on the analysis of illuminance uniformity of target regions by simulation and grey scale uniformity and articulation that are calculated from grey imagery. Currently, in order to apply the Pulse Coupled Neural Network (PCNN) method, structural parameters must be tested and adjusted repeatedly. Therefore, this paper proposes the use of a particle swarm optimization (PSO) algorithm, in which the maximum between cluster variance rules is used as fitness function with a linearily reduced inertia factor. This algorithm is used to adaptively set PCNN connection coefficients and dynamic threshold, which avoids algorithmic precocity and local oscillations. The proposed method is used for pivot bearing defect image processing. The segmentation results of the maximum entropy and minimum error method and the one described in this paper are compared using buffer region matching, and the experimental results show that the method of this paper is effective.
A Micro Dynamically Tuned Gyroscope with Adjustable Static Capacitance
Lun Kong
2013-02-01
Full Text Available This paper presents a novel micro dynamically tuned gyroscope (MDTG with adjustable static capacitance. First, the principle of MDTG is theoretically analyzed. Next, some simulations under the optimized structure parameters are given as a reference for the mask design of the rotor wafer and electrode plates. As two key components, the process flows of the rotor wafer and electrode plates are described in detail. All the scanning electron microscopy (SEM photos show that the fabrication process is effective and optimized. Then, an assembly model is designed for the static capacitance adjustable MDTG, whose static capacitance can be changed by rotating the lower electrode plate support and substituting gasket rings of different thicknesses. Thus, the scale factor is easily changeable. Afterwards, the digitalized closed-loop measurement circuit is simulated. The discrete correction and decoupling modules are designed to make the closed-loop stable and cross-coupling effect small. The dual axis closed-loop system bandwidths can reach more than 60 Hz and the dual axis scale factors are completely symmetrical. All the simulation results demonstrate the proposed fabrication of the MDTG can meet the application requirements. Finally, the paper presents the test results of static and dynamic capacitance values which are consistent with the simulation values.
A micro dynamically tuned gyroscope with adjustable static capacitance.
Xia, Dunzhu; Yu, Cheng; Kong, Lun
2013-02-06
This paper presents a novel micro dynamically tuned gyroscope (MDTG) with adjustable static capacitance. First, the principle of MDTG is theoretically analyzed. Next, some simulations under the optimized structure parameters are given as a reference for the mask design of the rotor wafer and electrode plates. As two key components, the process flows of the rotor wafer and electrode plates are described in detail. All the scanning electron microscopy (SEM) photos show that the fabrication process is effective and optimized. Then, an assembly model is designed for the static capacitance adjustable MDTG, whose static capacitance can be changed by rotating the lower electrode plate support and substituting gasket rings of different thicknesses. Thus, the scale factor is easily changeable. Afterwards, the digitalized closed-loop measurement circuit is simulated. The discrete correction and decoupling modules are designed to make the closed-loop stable and cross-coupling effect small. The dual axis closed-loop system bandwidths can reach more than 60 Hz and the dual axis scale factors are completely symmetrical. All the simulation results demonstrate the proposed fabrication of the MDTG can meet the application requirements. Finally, the paper presents the test results of static and dynamic capacitance values which are consistent with the simulation values.
Modal Analysis of a Single-Structure Multiaxis MEMS Gyroscope
Muhammad Ali Shah
2016-01-01
Full Text Available This paper reports on designing a single-structure triaxes MEMS capacitive gyroscope which is capable of measuring the three angular velocities on a single drive. A Z-shaped beam for the support of folded coupling spring has been applied to suppress the unwanted mode and decrease the stress effect at the spring ends. The unique coupling spring has changed the driving motion, due to which slide film damping in the driving mode has been reduced. This reduction can lead to higher performance of the sensor with less requirements on vacuum level which decreases the cost of fabrication. Simulation analysis has been performed in COMSOL Multiphysics and Matlab Simulink to finalize the design for fabrication. After finite element analysis, the driving, x-sensing, z-sensing, and y-sensing are, respectively, found to be 13.30 KHz, 13.40 KHz, 13.47 KHz, and 13.51 KHz.
Development of fiber optic gyroscopes for industrial and consumer applications
Ikeda, Yukio; Yuhara, Toshiya; Kumagai, Tatsuya; Soekawa, Hirokazu; Kajioka, Hiroshi
1995-01-01
This paper will present the current status of the fiber optic gyroscope (FOG), a ring interferometric rotation sensor for commercial applications by industries and consumers. An open-loop FOG with all polarization-maintaining fiber components is being used in these applications. One primary application is in vehicle navigation systems for automobiles, and a mass-produced has already been installed in luxury automobiles in Japan. Another application is in sweeper robots, Other applications such as a route-measuring system for boreholes, an attitude-controlling system for industrial helicopters, and an optocompass or north-seeking instrument will also be described. These FOGs are compact and reliable and need only a +12 V or a +24 V DC power source. This bias error is determined by the electrical system rather than the optical system and varies between 0.01 and 36 deg/h depending on the design of the signal-processing unit. The scale factor error varies between 0.1% and 1% also depending on the design, however, it is stable over the temperature range from -30 to 85 degree(s)C.
Atom gyroscope with disordered arrays of quantum rings
Dayon, Daniel J; Toland, John R E; Search, Chris P, E-mail: csearch@stevens.ed [Department of Physics and Engineering Physics, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)
2010-06-14
Atom interferometry is of considerable interest in part because of the ability to interferometrically detect inertial rotations via the Sagnac effect with a potential sensitivity 10{sup 10} greater than optical gyroscopes. It has been shown recently that a coherently coupled array of identical interferometers can significantly enhance the sensitivity to rotations due to the appearance of transmission bands as a function of the inertial rotation rate {Omega}. Here we consider phase coherent transport of atomic matter waves in a chain of ring interferometers with a single occupied transverse mode in the presence of a rotation, {Omega}, and study the effect of variations in the size of the rings. We show that for randomly sized rings, the entire array functions as a highly sensitive Sagnac interferometer provided the level of random size fluctuations does not exceed a few per cent of the mean size. We also analyse how the use of individual defect states and controlled variations of the sizes in the array can be used to further enhance the sensitivity by creating narrow transmission resonances inside of a zero transmission gap.
Gyroscopic stimulation of the semicircular canals during sensory deprivation.
Newsom, B. D.; Brady, J. F.; Stumm, J. E.
1971-01-01
A static object revolving at a constant velocity is stationary with respect to that environment. When the object is rotated outside the plane of spin, a gyroscopic or cross-coupled acceleration is produced orthogonal to the two planes of rotation. In this situation, a man feels himself moving in a direction other than that which his visual or proprioceptive sensors perceive. The conflict in spatial orientation is the cross-coupled acceleration imposed on the semicircular canals. This perceptual conflict and the thresholds involved were studied by partial isolation of the physiological stimuli through sensory deprivation. Subjects weighted to neutral buoyancy were submerged in 94 F water in the dark. The subjects were then rotated while being revolved about a displaced axis. Thresholds for detection of angular acceleration were higher than those reported in the literature for detection of acceleration of a single plane. This discrepancy may be attributable to the length of time the stimuli are imposed to each of the canals and the cupular response periods.
Medication Errors In Relation To Education & Years of Nursing Experience
2012-01-01
Medication error is defined as any preventable event that might cause or lead to an inappropriate use orharming of the patient. The purpose of this study was to determine the relationship between the level ofeducation and medication errors; years of work experience and medication errors. With a betterunderstanding of these relationships, nursing professionals can learn what characteristics tend to make anurse prone to medication errors and can develop methods and procedures to reduce incidenc...
Hypervelocity Impact Experiments in the Laboratory Relating to Lunar Astrobiology
Burchell, M. J.; Parnell, J.; Bowden, S. A.; Crawford, I. A.
2010-12-01
The results of a set of laboratory impact experiments (speeds in the range 1-5 km s-1) are reviewed. They are discussed in the context of terrestrial impact ejecta impacting the Moon and hence lunar astrobiology through using the Moon to learn about the history of life on Earth. A review of recent results indicates that survival of quite complex organic molecules can be expected in terrestrial meteorites impacting the lunar surface, but they may have undergone selective thermal processing both during ejection from the Earth and during lunar impact. Depending on the conditions of the lunar impact (speed, angle of impact etc.) the shock pressures generated can cause significant but not complete sterilisation of any microbial load on a meteorite (e.g. at a few GPa 1-0.1% of the microbial load can survive, but at 20 GPa this falls to typically 0.01-0.001%). For more sophisticated biological products such as seeds (trapped in rocks) the lunar impact speeds generate shock pressures that disrupt the seeds (experiments show this occurs at approximately 1 GPa or semi-equivalently 1 km s-1). Overall, the delivery of terrestrial material of astrobiological interest to the Moon is supported by these experiments, although its long term survival on the Moon is a separate issue not discussed here.
Subjective experiences in first-degree relatives of schizophrenic subjects.
Loas, Gwenolé; Dimassi, Hajer; Yon, Valérie; Monestes, Jean Louis
2012-10-01
First-degree relatives of patients with schizophrenia may score higher on the Frankfurt Complaint Questionnaire (FCQ) than controls. The present study was designed to provide evidence of validity for the French version of the 24-item subscale of the Frankfurt Complaint Questionnaire (FCQ-24). In 27 first-degree relatives of patients with schizophrenia (high-risk group) and 30 controls, the high-risk group scored significantly higher on the FCQ, as expected.
Mian, Muhammad Umer, E-mail: umermian@gmail.com; Khir, M. H. Md.; Tang, T. B. [Department of Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia); Dennis, John Ojur [Department of Fundamental & Applied Sciences, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia); Riaz, Kashif; Iqbal, Abid [Faculty of Electronics Engineering, GIK Institute of Engineering Sciences and Technology, Topi, Khyber Pakhtunkhaw (Pakistan); Bazaz, Shafaat A. [Department of Computer Science, Center for Advance Studies in Engineering, Islamabad (Pakistan)
2015-07-22
Pre-fabrication, behavioural and performance analysis with computer aided design (CAD) tools is a common and fabrication cost effective practice. In light of this we present a simulation methodology for a dual-mass oscillator based 3 Degree of Freedom (3-DoF) MEMS gyroscope. 3-DoF Gyroscope is modeled through lumped parameter models using equivalent circuit elements. These equivalent circuits consist of elementary components which are counterpart of their respective mechanical components, used to design and fabricate 3-DoF MEMS gyroscope. Complete designing of equivalent circuit model, mathematical modeling and simulation are being presented in this paper. Behaviors of the equivalent lumped models derived for the proposed device design are simulated in MEMSPRO T-SPICE software. Simulations are carried out with the design specifications following design rules of the MetalMUMPS fabrication process. Drive mass resonant frequencies simulated by this technique are 1.59 kHz and 2.05 kHz respectively, which are close to the resonant frequencies found by the analytical formulation of the gyroscope. The lumped equivalent circuit modeling technique proved to be a time efficient modeling technique for the analysis of complex MEMS devices like 3-DoF gyroscopes. The technique proves to be an alternative approach to the complex and time consuming couple field analysis Finite Element Analysis (FEA) previously used.
Mian, Muhammad Umer; Dennis, John Ojur; Khir, M. H. Md.; Riaz, Kashif; Iqbal, Abid; Bazaz, Shafaat A.; Tang, T. B.
2015-07-01
Pre-fabrication, behavioural and performance analysis with computer aided design (CAD) tools is a common and fabrication cost effective practice. In light of this we present a simulation methodology for a dual-mass oscillator based 3 Degree of Freedom (3-DoF) MEMS gyroscope. 3-DoF Gyroscope is modeled through lumped parameter models using equivalent circuit elements. These equivalent circuits consist of elementary components which are counterpart of their respective mechanical components, used to design and fabricate 3-DoF MEMS gyroscope. Complete designing of equivalent circuit model, mathematical modeling and simulation are being presented in this paper. Behaviors of the equivalent lumped models derived for the proposed device design are simulated in MEMSPRO T-SPICE software. Simulations are carried out with the design specifications following design rules of the MetalMUMPS fabrication process. Drive mass resonant frequencies simulated by this technique are 1.59 kHz and 2.05 kHz respectively, which are close to the resonant frequencies found by the analytical formulation of the gyroscope. The lumped equivalent circuit modeling technique proved to be a time efficient modeling technique for the analysis of complex MEMS devices like 3-DoF gyroscopes. The technique proves to be an alternative approach to the complex and time consuming couple field analysis Finite Element Analysis (FEA) previously used.
Relativity effects for space-based coherent lidar experiments
Gudimetla, V. S. Rao
1996-01-01
An effort was initiated last year in the Astrionics Laboratory at Marshall Space Flight Center to examine and incorporate, if necessary, the effects of relativity in the design of space-based lidar systems. A space-based lidar system, named AEOLUS, is under development at Marshall Space Flight Center and it will be used to accurately measure atmospheric wind profiles. Effects of relativity were also observed in the performance of space-based systems, for example in case of global positioning systems, and corrections were incorporated into the design of instruments. During the last summer, the effects of special relativity on the design of space-based lidar systems were studied in detail, by analyzing the problem of laser scattering off a fixed target when the source and a co-located receiver are moving on a spacecraft. Since the proposed lidar system uses a coherent detection system, errors even in the order of a few microradians must be corrected to achieve a good signal-to-noise ratio. Previous analysis assumed that the ground is flat and the spacecraft is moving parallel to the ground, and developed analytical expressions for the location, direction and Doppler shift of the returning radiation. Because of the assumptions used in that analysis, only special relativity effects were involved. In this report, that analysis is extended to include general relativity and calculate its effects on the design.
Williams, Christine M.; Subich, Linda M.
2006-01-01
The learning experiences questionnaire (LEQ; Schaub & Tokar, 2005) was used to examine learning experiences as they relate to SCCT (Lent, Brown, & Hackett, 1994) across the Holland (1997) RIASEC typology. In particular, differences in men's and women's career related learning experiences were examined. A sample of 319 undergraduates at a public…
Sports-related shoulder dislocations: a state-hospital experience.
Hazmy, C H Wan; Parwathi, A
2005-07-01
This retrospective study was conducted in a state hospital set-up and aimed at identifying the incidence of sports-related shoulder dislocations and their characteristics and the sports events involved. All patients with shoulder dislocation related to sporting activities admitted to the hospital from January 1999 to December 2002 were included in the study. There were 18 sports-related shoulder dislocations out of 106 all shoulder dislocations admitted during this 4-year period. The average age of the patients was 25.4 years. All but two were male. All were anterior dislocations. Recurrent dislocation constitutes 78% of the cases with an average of 3 times re-dislocation. Rugby and badminton were the major contributors to the injuries followed by volleyball, soccer and swimming. Conservative treatment was successfully instituted for 88% of the patients and 12% opted for surgical intervention.
Being a team leader: newly registered nurses relate their experiences.
Ekström, Louise; Idvall, Ewa
2015-01-01
This paper presents a study that explores how newly qualified registered nurses experience their leadership role in the ward-based nursing care team. A nurse's clinical leadership affects the quality of care provided. Newly qualified nurses experience difficulties during the transition period from student to qualified professional and find it challenging to lead nursing care. Twelve nurses were interviewed and the transcribed texts analysed using qualitative content analysis to assess both manifest and latent content. Five themes were identified: feeling stranded; forming well-functioning teams; learning to lead; having the courage, strength, and desire to lead; and ensuring appropriate care. The findings indicate that many factors limit nurses' leadership but some circumstances are supportive. The leadership prerequisites for newly registered nurses need to improve, emphasizing different ways to create a supportive atmosphere that promotes professional development and job satisfaction. To increase nurse retention and promote quality of care, nurse managers need to clarify expectations and guide and support newly qualified nurses in a planned way. © 2013 John Wiley & Sons Ltd.
Xudong Yu; Yu Wang; Guo Wei; Pengfei Zhang; Xingwu Long
2011-01-01
Bias of ring-laser-gyroscope (RLG) changes with temperature in a nonlinear way. This is an important restraining factor for improving the accuracy of RLG. Considering the limitations of least-squares regression and neural network, we propose a new method of temperature compensation of RLG bias-building function regression model using least-squares support vector machine (LS-SVM). Static and dynamic temperature experiments of RLG bias are carried out to validate the effectiveness of the proposed method. Moreover,the traditional least-squares regression method is compared with the LS-SVM-based method. The results show the maximum error of RLG bias drops by almost two orders of magnitude after static temperature compensation, while bias stability of RLG improves by one order of magnitude after dynamic temperature compensation. Thus, the proposed method reduces the influence of temperature variation on the bias of the RLG effectively and improves the accuracy of the gyro scope considerably.%@@ Bias of ring-laser-gyroscope (RLG) changes with temperature in a nonlinear way.This is an important restraining factor for improving the accuracy of RLG.Considering the limitations of least-squares regression and neural network, we propose a new method of temperature compensation of RLG bias-building function regression model using least-squares support vector machine (LS-SVM).Static and dynamic temperature experiments of RLG bias are carried out to validate the effectiveness of the proposed method.Moreover,the traditional least-squares regression method is compared with the LS-SVM-based method.
The GINGERino ring laser gyroscope, seismological observations at one year from the first light
Simonelli, Andreino; Belfi, Jacopo; Beverini, Nicolò; Di Virgilio, Angela; Carelli, Giorgio; Maccioni, Enrico; De Luca, Gaetano; Saccorotti, Gilberto
2016-04-01
The GINGERino ring laser gyroscope (RLG) is a new large observatory-class RLG located in Gran Sasso underground laboratory (LNGS), one national laboratory of the INFN (Istituto Nazionale di Fisica Nucleare). The GINGERino apparatus funded by INFN in the context of a larger project of fundamental physics is intended as a pathfinder instrument to reach the high sensitivity needed to observe general relativity effects; more details are found at the URL (https://web2.infn.it/GINGER/index.php/it/). The sensitivity reached by our instrument in the first year after the set up permitted us to acquire important seismological data of ground rotations during the transit of seismic waves generated by seisms at different epicentral distances. RLGs are in fact the best sensors for capturing the rotational motions associated with the transit of seismic waves, thanks to the optical measurement principle, these instruments are in fact insensitive to translations. Ground translations are recorded by two seismometers: a Nanometrics Trillium 240 s and Guralp CMG 3T 360 s, the first instrument is part of the national earthquake monitoring program of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and provides the ground translation data to be compared to the RLG rotational data. We report the waveforms and the seismological analysis of some seismic events recorded during our first year of activity inside the LNGS laboratory.
Stair climbing detection during daily physical activity using a miniature gyroscope.
Coley, Brian; Najafi, Bijan; Paraschiv-Ionescu, Anisoara; Aminian, Kamiar
2005-12-01
A new method of monitoring physical activity that is able to detect walking upstairs using a miniature gyroscope attached to the shank is presented. Wavelet transformation, in conjunction with a simple kinematics model, was used to detect toe-off, heel-strike and foot-flat, as well cycles corresponding to stair ascent. To evaluate the system, three studies were performed. The method was first tested on 10 healthy young volunteer subjects in a gait laboratory where an ultrasonic motion system was used as a reference system. In the second study, the system was tested on three hospitalized elderly people to classify walking upstairs from walking downstairs and flat walking. In the third study, monitoring was performed on seven patients with peripheral vascular disease for 60min during their daily physical activity. The first study revealed a close relationship between the ambulatory and the reference systems. Compared to the reference system, the ambulatory system had an overall sensitivity and specificity of 98% and 97%, respectively. In the second study, the ambulatory system also showed a very high sensitivity (>94%) in identifying a 50 stairs ascent from walking on the flat and walking downstairs. Finally, compared with visual surveillance, we observed a relatively high accuracy in identifying 196 walking upstairs cycles through daily physical activity in the third study. Our results demonstrated a reliable technique of measuring walking upstairs during physical activity.
Modeling and Analysis of Mechanical Quality Factor of the Resonator for Cylinder Vibratory Gyroscope
XI Xiang; WU Xuezhong; WU Yulie; ZHANG Yongmeng
2017-01-01
Mechanical Quality factor(Q factor) of the resonator is an important parameter for the cylinder vibratory gyroscope(CVG).Traditional analytical methods mainly focus on a partial energy loss during the vibration process of the CVG resonator,thus are not accurate for the mechanical Q factor prediction.Therefore an integrated model including air damping loss,surface defect loss,support loss,thermoelastic damping loss and internal friction loss is proposed to obtain the mechanical Q factor of the CVG resonator.Based on structural dynamics and energy dissipation analysis,the contribution of each energy loss to the total mechanical Q factor is quantificationally analyzed.For the resonator with radius ranging from 10 mm to 20 mm,its mechanical Q factor is mainly related to the support loss,thermoelastic damping loss and internal friction loss,which are fundamentally determined by the geometric sizes and material properties of the resonator.In addition,resonators made of alloy 3J53 (Ni42CrTiA1),with different sizes,were experimentally fabricated to test the mechanical Q factor.The theoretical model is well verified by the experimental data,thus provides an effective theoretical method to design and predict the mechanical Q factor of the CVG resonator.
High-Q microsphere resonators for angular velocity sensing in gyroscopes
An, Panlong [Key Laboratory of Instrumentation Science and Dynamic Measurement, Ministry of Education, Taiyuan 030051 (China); School of Science, North University of China, Taiyuan 030051 (China); Zheng, Yongqiu [Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051 (China); Yan, Shubin, E-mail: shubin-yan@nuc.edu.cn; Xue, Chenyang, E-mail: xuechenyang@nuc.edu.cn; Liu, Jun, E-mail: liuj@nuc.edu.cn [Key Laboratory of Instrumentation Science and Dynamic Measurement, Ministry of Education, Taiyuan 030051 (China); Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051 (China); Wang, Wanjun [Department of Mechanical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)
2015-02-09
A resonator gyroscope based on the Sagnac effect is proposed using a core unit that is generated by water-hydrogen flame melting. The relationship between the quality factor Q and diameter D is revealed. The Q factor of the spectral lines of the microsphere cavity coupling system, which uses tapered fibers, is found to be 10{sup 6} or more before packaging with a low refractive curable ultraviolet polymer, although it drops to approximately 10{sup 5} after packaging. In addition, a rotating test platform is built, and the transmission spectrum and discriminator curves of a microsphere cavity with Q of 3.22×10{sup 6} are measured using a semiconductor laser (linewidth less than 1 kHz) and a real-time proportional-integral circuit tracking and feedback technique. Equations fitting the relation between the voltage and angular rotation rate are obtained. According to the experimentally measured parameters, the sensitivity of the microsphere-coupled system can reach 0.095{sup ∘}/s.
Fall-detection solution for mobile platforms using accelerometer and gyroscope data.
De Cillisy, Francesca; De Simioy, Francesca; Guidoy, Floriana; Incalzi, Raffaele Antonelli; Setolay, Roberto
2015-08-01
Falls are a major health risk that diminish the quality of life among elderly people. Apart from falls themselves, most dramatic consequences are usually related with long lying periods that can cause serious side effects. These findings call for pervasive long-term fall detection systems able to automatically detect falls. In this paper, we propose an effective fall detection algorithm for mobile platforms. Using data retrieved from wearable sensors, such as Inertial Measurements Units (IMUs) and/or SmartPhones (SPs), our algorithm is able to detect falls using features extracted from accelerometer and gyroscope. While mostly of the mobile-based solutions for fall management deal only with accelerometer data, in the proposed approach we combine the instantaneous acceleration magnitude vector with changes of the user's heading in a Threshold Based Algorithm (TBA). In such a way, we were able to handle falls detection with minimal computational load, increasing the overall system accuracy with respect to traditional fall management methods. Experimental results show the strong detection performance of the proposed solution in discriminating between falls and typical Activities of Daily Living (ADLs) presenting fall-like acceleration patterns.
Modeling and analysis of mechanical Quality factor of the resonator for cylinder vibratory gyroscope
Xi, Xiang; Wu, Xuezhong; Wu, Yulie; Zhang, Yongmeng
2016-08-01
Mechanical Quality factor(Q factor) of the resonator is an important parameter for the cylinder vibratory gyroscope(CVG). Traditional analytical methods mainly focus on a partial energy loss during the vibration process of the CVG resonator, thus are not accurate for the mechanical Q factor prediction. Therefore an integrated model including air damping loss, surface defect loss, support loss, thermoelastic damping loss and internal friction loss is proposed to obtain the mechanical Q factor of the CVG resonator. Based on structural dynamics and energy dissipation analysis, the contribution of each energy loss to the total mechanical Q factor is quantificationally analyzed. For the resonator with radius ranging from 10 mm to 20 mm, its mechanical Q factor is mainly related to the support loss, thermoelastic damping loss and internal friction loss, which are fundamentally determined by the geometric sizes and material properties of the resonator. In addition, resonators made of alloy 3J53 (Ni42CrTiAl), with different sizes, were experimentally fabricated to test the mechanical Q factor. The theoretical model is well verified by the experimental data, thus provides an effective theoretical method to design and predict the mechanical Q factor of the CVG resonator.
CETA and Sex Related Wage Differentials: The Boston Experience.
Sawhney, Pawan K.; Jantzen, Robert H.
1981-01-01
This study assessed the impact of the CETA program on the sexual wage differential of participants. The sources of sex-related wage differentials among CETA Title I (now Title IIB) participants before and after program participation are analyzed in order to examine the impact of training on the earnings gap. (CT)
Clinician experiences assessing work disability related to mental disorders
Dewa, C.S.; Hees, H.; Trojanowski, L.; Schene, A.H.
2015-01-01
OBJECTIVE: Medical certification is one of the basic administrative mechanisms used by social policies aimed at income protection. The assessment of work disability is central to the income protection application. Yet, there is evidence suggesting that determining work disability related to mental
The Experience of Age-Related Macular Degeneration
Wong, Elaine Y. H.; Guymer, Robyn H.; Hassell, Jennifer B.; Keeffe, Jill E.
2004-01-01
This qualitative article describes the impact of age-related macular degeneration (ARMD) among 15 participants: how a person makes sense of ARMD, the effect of ARMD on the person's quality of life, the psychological disturbances associated with the limitations of ARMD, and the influence of ARMD on social interactions. Such in-depth appreciation of…
Commercial Aircraft Maintenance Experience Relating to Engine External Hardware
Soditus, Sharon M.
2006-01-01
Airlines are extremely sensitive to the amount of dollars spent on maintaining the external engine hardware in the field. Analysis reveals that many problems revolve around a central issue, reliability. Fuel and oil leakage due to seal failure and electrical fault messages due to wire harness failures play a major role in aircraft delays and cancellations (D&C's) and scheduled maintenance. Correcting these items on the line requires a large investment of engineering resources and manpower after the fact. The smartest and most cost effective philosophy is to build the best hardware the first time. The only way to do that is to completely understand and model the operating environment, study the field experience of similar designs and to perform extensive testing.
Utilization of the BARC critical facility for ADS related experiments
Rajeev Kumar; R Srivenkatesan
2007-02-01
The paper discusses the basic design of the critical facility, whose main purpose is the physics validation of AHWR. Apart from moderator level control, the facility will have shutdown systems based on shutoff rods and multiple ranges of neutron detection systems. In addition, it will have a flux mapping system based on 25 fission chambers, distributed in the core. We are planning to use this reactor for experiments with a suitable source to simulate an ADS system. Any desired sub-criticality can be achieved by adjusting the moderator level. Apart from perfecting our experimental techniques, in simple configurations, we intend to study the one-way coupled core in this facility. Preliminary calculations, employing a Monte Carlo code TRIPOLI, are presented.
Setaka, Wataru; Ohmizu, Soichiro; Kira, Mitsuo
2014-02-01
Macrocage molecules with a bridged rotor have been synthesized as molecular gyroscopes. The kinetics of the oxidation reaction of the thiophene-bridged molecular gyroscope, whose thiophene ring was bridged inside a silaalkane cage, was investigated. A remarkable kinetic stabilization against the oxidation of the thiophene moiety induced by the molecular cage framework was observed.
Limits to relational autonomy--the Singaporean experience.
Krishna, Lalit Kumar Radha; Watkinson, Deborah S; Beng, Ng Lee
2015-05-01
Recognition that the Principle of Respect for Autonomy fails to work in family-centric societies such as Singapore has recently led to the promotion of relational autonomy as a suitable framework within which to place healthcare decision making. However, empirical data, relating to patient and family opinions and the practices of healthcare professionals in Confucian-inspired Singapore, demonstrate clear limitations on the ability of a relational autonomy framework to provide the anticipated compromise between prevailing family decision-making norms and adopted Western led atomistic concepts of autonomy. Evidence suggests that despite a growing infusion of Western influence, there is still little to indicate any major shift to individual decision making, particularly in light of the way society and healthcare are structured. Similarly, the lack of employing a shared decision-making model and data that discredit the notion that the complex psychosocial and cultural factors that affect the decision making may be considered "content neutral" not only prevents the application of relational autonomy but questions the viability of the values behind the Principle of Respect for Autonomy. Taking into account local data and drawing upon a wider concept of personhood that extends beyond prevailing family-centric ideals along with the complex interests that are focused upon the preservation of the unique nature of personhood that arises from the Ring Theory of Personhood, we propose and "operationalize" the employing of an authoritative welfare-based approach, within the confines of best interest decision making, to better meet the current care needs within Singapore. © The Author(s) 2014.
Design and simulation of a tuning fork micromachined gyroscope with slide film damping
CHE Lu-feng; XIONG Bin; JIAO Ji-wei; WANG Yue-lin
2005-01-01
A novel tuning fork micromachined gyroscope, based on slide-film damping, is presented. The electrostatic driving gyroscope consists of two driving masses each of which supports one sensitive mass. The angular rate is sensed by the differential capacitances consisted of movable bar electrodes and fixed bar electrodes located on the glass wafer. The gyroscope can operate at atmospheric pressure with slide film damping in the driving and sensing directions, eliminate vacuum packaging and restrain cross-axis acceleration signal. The results of design and simulation show that the driving and sensing mode frequencies are 3 106 Hz and 3 175 Hz,respectively, and the Q-values in driving and sensitive modes are 1 721 and 1 450 respectively. The design resolution is 0.025°/s.
Adaptive Global Sliding Mode Control for MEMS Gyroscope Using RBF Neural Network
Yundi Chu
2015-01-01
Full Text Available An adaptive global sliding mode control (AGSMC using RBF neural network (RBFNN is proposed for the system identification and tracking control of micro-electro-mechanical system (MEMS gyroscope. Firstly, a new kind of adaptive identification method based on the global sliding mode controller is designed to update and estimate angular velocity and other system parameters of MEMS gyroscope online. Moreover, the output of adaptive neural network control is used to adjust the switch gain of sliding mode control dynamically to approach the upper bound of unknown disturbances. In this way, the switch item of sliding mode control can be converted to the output of continuous neural network which can weaken the chattering in the sliding mode control in contrast to the conventional fixed gain sliding mode control. Simulation results show that the designed control system can get satisfactory tracking performance and effective estimation of unknown parameters of MEMS gyroscope.
Integrated optical gyroscope using active long-range surface plasmon-polariton waveguide resonator.
Zhang, Tong; Qian, Guang; Wang, Yang-Yang; Xue, Xiao-Jun; Shan, Feng; Li, Ruo-Zhou; Wu, Jing-Yuan; Zhang, Xiao-Yang
2014-01-24
Optical gyroscopes with high sensitivity are important rotation sensors for inertial navigation systems. Here, we present the concept of integrated resonant optical gyroscope constructed by active long-range surface plasmon-polariton (LRSPP) waveguide resonator. In this gyroscope, LRSPP waveguide doped gain medium is pumped to compensate the propagation loss, which has lower pump noise than that of conventional optical waveguide. Peculiar properties of single-polarization of LRSPP waveguide have been found to significantly reduce the polarization error. The metal layer of LRSPP waveguide is electro-optical multiplexed for suppression of reciprocal noises. It shows a limited sensitivity of ~10(-4) deg/h, and a maximum zero drift which is 4 orders of magnitude lower than that constructed by conventional single-mode waveguide.
Anomalous Fiber Optic Gyroscope Signals Observed above Spinning Rings at Low Temperature
Tajmar, M; Seifert, B
2008-01-01
Precision fiber optic gyroscopes were mounted mechanically de-coupled above spinning rings inside a cryostat. Below a critical temperature (typically <30 K), the gyroscopes measure a significant deviation from their usual Earth rotation offset proportional to the applied angular ring velocity with maximum signals towards lower temperatures. The anomalous gyroscope signal is about 8 orders of magnitude smaller then the applied angular ring velocity, compensating about one third of the Earth rotation offset at an angular top speed of 420 rad/s. Moreover, our data shows a parity violation as the effect appears to be dominant for rotation against the Earth's spin. No systematic effect was found to explain this effect including the magnetic environment, vibration and helium gas friction suggesting that our observation is a new low temperature phenomenon. Tests in various configurations suggest that the anomalous signals is originating from the rotating helium in our facilities.
Deng, Yan; Zhou, Bin; Xing, Chao; Zhang, Rong
2014-10-17
A novel multifrequency excitation (MFE) method is proposed to realize rapid and accurate dynamic testing of micromachined gyroscope chips. Compared with the traditional sweep-frequency excitation (SFE) method, the computational time for testing one chip under four modes at a 1-Hz frequency resolution and 600-Hz bandwidth was dramatically reduced from 10 min to 6 s. A multifrequency signal with an equal amplitude and initial linear-phase-difference distribution was generated to ensure test repeatability and accuracy. The current test system based on LabVIEW using the SFE method was modified to use the MFE method without any hardware changes. The experimental results verified that the MFE method can be an ideal solution for large-scale dynamic testing of gyroscope chips and gyroscopes.
Zhentao Wang
2012-01-01
Full Text Available Fault detection and isolation (FDI in rotor systems often faces the problem that the system dynamics is dependent on the rotor rotary frequency because of the gyroscopic effect. In unbalance excited rotor systems, the continuously distributed unbalances are hard to be determined or estimated accurately. The unbalance forces as disturbances make fault detection more complicated. The aim of this paper is to develop linear time invariant (LTI FDI methods (i.e., with constant parameters for rotor systems under consideration of gyroscopic effect and disturbances. Two approaches to describe the gyroscopic effect, that is, as unknown inputs and as model uncertainties, are investigated. Based on these two approaches, FDI methods are developed and the results are compared regarding the resulting FDI performances. Results are obtained by the application in a rotor test rig. Restrictions for the application of these methods are discussed.
Research on Time-series Modeling and Filtering Methods for MEMS Gyroscope Random Drift Error
Wang, Xiao Yi; Meng, Xiu Yun
2017-03-01
The precision of MEMS gyroscope is reduced by random drift error. This paper applied time series analysis to model random drift error of MEMS gyroscope. Based on the model established, Kalman filter was employed to compensate for the error. To overcome the disadvantages of conventional Kalman filter, Sage-Husa adaptive filtering algorithm was utilized to improve the accuracy of filtering results and the orthogonal property of innovation in the process of filtering was utilized to deal with outliers. The results showed that, compared with conventional Kalman filter, the modified filter can not only enhance filter accuracy, but also resist to outliers and this assured the stability of filtering thus improving the performance of gyroscopes.
Study on digital correlation demodulation technology of micro quartz tuning fork gyroscope
Zhang, Zhixiong; Feng, Lihui; Sun, Yu-Nan
2010-11-01
A signal demodulation scheme for micro quartz tuning fork gyroscope based on digital correlation demodulation technology is proposed. In the operation of quartz gyroscope the reference signal should be in the resonance state with steady amplitude and the reference signal should be in-phase and has the same frequency with the driving signal. The quartz gyroscope signal processing platform is designed on the foundation of DEC6713 DSP development board successfully. The adaptive algorithm including the reference signal frequency tacking, the amplitude automatic gain controlling, the reference signal phase locking, and complex correlation demodulation are devised, and the algorithm is programmed. It is proved that the digital signal process scheme is feasible by means of experimentation.
Yan Deng
2014-10-01
Full Text Available A novel multifrequency excitation (MFE method is proposed to realize rapid and accurate dynamic testing of micromachined gyroscope chips. Compared with the traditional sweep-frequency excitation (SFE method, the computational time for testing one chip under four modes at a 1-Hz frequency resolution and 600-Hz bandwidth was dramatically reduced from 10 min to 6 s. A multifrequency signal with an equal amplitude and initial linear-phase-difference distribution was generated to ensure test repeatability and accuracy. The current test system based on LabVIEW using the SFE method was modified to use the MFE method without any hardware changes. The experimental results verified that the MFE method can be an ideal solution for large-scale dynamic testing of gyroscope chips and gyroscopes.
Tian, W.
2016-07-01
Ring laser gyroscope technique directly senses the Earth's instantaneous rotation pole (IRP), whose polar motion contains strong retrograde diurnal components induced by external torques due to the gravitational attraction of the Moon and Sun. The first direct measurement of this retrograde diurnal motion with three large ring lasers was reported by Schreiber et al. (J Geophys Res 109(B18):B06405, 2004). Since then many technical improvements led to a significant increase in precision and stability of ring laser gyroscopes; however, precise determination of amplitude and phase at main partial waves has not been given in the literature. In this paper, I will report on determination of the retrograde diurnal motion of the IRP at main partial waves (Oo_1, J_1, K_1, M_1, O_1, Q_1 ) by the ring laser "G", located in Wettzell, Germany, which is the most stable one amongst the currently running large ring laser gyroscopes.
Tian, W.
2017-01-01
Ring laser gyroscope technique directly senses the Earth's instantaneous rotation pole (IRP), whose polar motion contains strong retrograde diurnal components induced by external torques due to the gravitational attraction of the Moon and Sun. The first direct measurement of this retrograde diurnal motion with three large ring lasers was reported by Schreiber et al. (J Geophys Res 109(B18):B06405, significant increase in precision and stability of ring laser gyroscopes; however, precise determination of amplitude and phase at main partial waves has not been given in the literature. In this paper, I will report on determination of the retrograde diurnal motion of the IRP at main partial waves (Oo_1, J_1, K_1, M_1, O_1, Q_1) by the ring laser "G", located in Wettzell, Germany, which is the most stable one amongst the currently running large ring laser gyroscopes.
Anomalous fiber optic gyroscope signals observed above spinning rings at low temperature
Tajmar, M; Plesescu, F; Seifert, B [Space Propulsion and Advanced Concepts, Austrian Research Centers GmbH - ARC, A-2444 Seibersdorf (Austria)], E-mail: martin.tajmar@arcs.ac.at
2009-02-01
Precision fiber optic gyroscopes were mounted mechanically de-coupled above spinning rings inside a cryostat. Below a critical temperature (typically <30 K), the gyroscopes measure a significant deviation from their usual offset due to Earth's rotation. This deviation is proportional to the applied angular ring velocity with maximum signals towards lower temperatures. The anomalous gyroscope signal is about 8 orders of magnitude smaller then the applied angular ring velocity, compensating about one third of the Earth rotation offset at an angular top speed of 420 rad/s. Moreover, our data shows a parity violation as the effect appears to be dominant for rotation against the Earth's spin. No systematic effect was found to explain this effect including the magnetic environment, vibration and helium gas friction suggesting that our observation is a new low temperature phenomenon. Tests in various configurations suggest that the rotating low temperature helium may be the source of our anomalous signals.
Enhanced sensitivity in a butterfly gyroscope with a hexagonal oblique beam
Xiao, Dingbang; Cao, Shijie; Hou, Zhanqiang, E-mail: houzhanqiang@nudt.edu.cn; Chen, Zhihua; Wang, Xinghua; Wu, Xuezhong [College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha, Hunan, 410073 (China)
2015-04-15
A new approach to improve the performance of a butterfly gyroscope is developed. The methodology provides a simple way to improve the gyroscope’s sensitivity and stability, by reducing the resonant frequency mismatch between the drive and sense modes. This method was verified by simulations and theoretical analysis. The size of the hexagonal section oblique beam is the major factor that influences the resonant frequency mismatch. A prototype, which has the appropriately sized oblique beam, was fabricated using precise, time-controlled multilayer pre-buried masks. The performance of this prototype was compared with a non-tuned gyroscope. The scale factor of the prototype reaches 30.13 mV/ °/s, which is 15 times larger than that obtained from the non-tuned gyroscope. The bias stability of the prototype is 0.8 °/h, which is better than the 5.2 °/h of the non-tuned devices.
Propagation-related AMT design aspects and supporting experiments
Dessouky, Khaled; Estabrook, Polly
1991-01-01
The ACTS Mobile Terminal (AMT) is presently being developed with the goal of significantly extending commercial satellite applications and their user base. A thorough knowledge of the Ka-band channel characteristics is essential to the proper design of a commercially viable system that efficiently utilizes the valuable resources. To date, only limited tests have been performed to characterize the Ka-band channel, and they have focused on the needs of fixed terminals. As part of the value of the AMT as a Ka-band test bed is its function as a vehicle through which tests specifically applicable to the mobile satellite communications can be performed. The exact propagation environment with the proper set of elevation angles, vehicle antenna gains and patterns, roadside shadowing, rain, and Doppler is encountered. The ability to measure all of the above, as well as correlate their effects with observed communication system performance, creates an invaluable opportunity to understand in depth Ka-band's potential in supporting mobile and personal communications. This paper discusses the propagation information required for system design, the setup with ACTS that will enable obtaining this information, and finally the types of experiments to be performed and data to be gathered by the AMT to meet this objective.
Alloys compatibility in molten salt fluorides: Kurchatov Institute related experience
Ignatiev, Victor, E-mail: ignatiev@vver.kiae.ru; Surenkov, Alexandr
2013-10-15
In the last several years, there has been an increased interest in the use of high-temperature molten salt fluorides in nuclear power systems. For all molten salt reactor designs, materials selection is a very important issue. This paper summarizes results, which led to selection of materials for molten salt reactors in Russia. Operating experience with corrosion thermal convection loops has demonstrated good capability of the “nickel–molybdenum alloys + fluoride salt fueled by UF{sub 4} and PuF{sub 3} + cover gas” system up to 750 °C. A brief description is given of the container material work in progress. Tellurium corrosion of Ni-based alloys in stressed and unloaded conditions studies was also tested in different molten salt mixtures at temperatures up to 700–750 °C, also with measurement of the redox potential. HN80MTY alloy with 1% added Al is the most resistant to tellurium intergranular cracking of Ni-base alloys under study.
Suicide in Relation to the Experience of Stressful Life Events
Fjeldsted, Rita; Teasdale, Thomas William; Jensen, Martin
2016-01-01
Stressful life events have been associated with high risk of suicidal behavior. The aim of this study was to examine whether persons who died by suicide in Denmark had more frequently been exposed to stressful life events, specifically divorce, death of a close relative, exposure to violence...... compared to controls. People who died by suicide had 1.5-fold (CI-95%: 1.3–1.6) higher risk of having experienced a divorce. Stressful life events, such as divorce and imprisonment, were more frequent in temporal proximity to the date of death among the suicide cases than for end of exposure for controls...
Profile of living related kidney donors: A single center experience
Hajji S
2010-01-01
Full Text Available The living related donor still represents the unique source for renal transplantation in Morocco. Since 1986, 127 living related potential donors have been evaluated and 100 patients have been transplanted at the Ibn Rochd UHC in Casablanca. We retrospectively studied the potential donors and determined their profile and the exclusion criteria. The mean age at the time of donation was 37 +/- 11 years (range 18-66 years and 60% of donors were women. The predominant sources of donors were sisters, brothers and mothers of recipients in 34%, 31% and 24% respectively. Forty three percent of them were married, 20% housewives and 17% unemployed. In addition, 37% were illiterate, 45% school graduates, and 18% university graduates. Donors and recipients were incom-plete HLA match in 72.7%, identical in 19% and different in 8.3%. The cross matching test was negative in all cases. The mean plasma creatinine was 0.8 ± 0.1 mg/dL with mean creatinine clearance of 103.16 ± 18.18 mL/min.
Optimization and Experimentation of Dual-Mass MEMS Gyroscope Quadrature Error Correction Methods
Huiliang Cao
2016-01-01
Full Text Available This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses’ quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC, Quadrature Force Correction (QFC and Coupling Stiffness Correction (CSC methods are introduced. The correction objects of these three methods are the quadrature error signal, force and the coupling stiffness, respectively. The three methods are investigated through control theory analysis, model simulation and circuit experiments, and the results support the theoretical analysis. The bias stability results based on CIC, QFC and CSC are 48 °/h, 9.9 °/h and 3.7 °/h, respectively, and this value is 38 °/h before quadrature error correction. The CSC method is proved to be the better method for quadrature correction, and it improves the Angle Random Walking (ARW value, increasing it from 0.66 °/√h to 0.21 °/√h. The CSC system general test results show that it works well across the full temperature range, and the bias stabilities of the six groups’ output data are 3.8 °/h, 3.6 °/h, 3.4 °/h, 3.1 °/h, 3.0 °/h and 4.2 °/h, respectively, which proves the system has excellent repeatability.
Optimization and Experimentation of Dual-Mass MEMS Gyroscope Quadrature Error Correction Methods.
Cao, Huiliang; Li, Hongsheng; Kou, Zhiwei; Shi, Yunbo; Tang, Jun; Ma, Zongmin; Shen, Chong; Liu, Jun
2016-01-07
This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses' quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC), Quadrature Force Correction (QFC) and Coupling Stiffness Correction (CSC) methods are introduced. The correction objects of these three methods are the quadrature error signal, force and the coupling stiffness, respectively. The three methods are investigated through control theory analysis, model simulation and circuit experiments, and the results support the theoretical analysis. The bias stability results based on CIC, QFC and CSC are 48 °/h, 9.9 °/h and 3.7 °/h, respectively, and this value is 38 °/h before quadrature error correction. The CSC method is proved to be the better method for quadrature correction, and it improves the Angle Random Walking (ARW) value, increasing it from 0.66 °/√h to 0.21 °/√h. The CSC system general test results show that it works well across the full temperature range, and the bias stabilities of the six groups' output data are 3.8 °/h, 3.6 °/h, 3.4 °/h, 3.1 °/h, 3.0 °/h and 4.2 °/h, respectively, which proves the system has excellent repeatability.
The mode matching technology for MEMS gyroscopes with mutually spaced eigenfrequencies
Morozov, O.; Postnikov, A.; Kozin, I.; Soloviev, A.; Tarasov, A.
2013-01-01
Paper presents a new technology for silicon micromachined gyroscope mode matching with mutually spaced eigenfrequencies. The fabrication of gyroscope sensing element is based on double-sided deep reactive ion etching (DRIE) of standard silicon wafer and allows full 3D control of the gimbals and flexures geometry. The developed finite element model allows predicting dynamic characteristics of sensing element versus geometry of flexible suspension beams. Oxidation and successive wet etching of SiO2 layer lead to flexure geometry change (thinning). One-to-one correspondence of measured resonant frequencies and flexures geometry defines the oxidation depth. The mode matching condition is achieved by repeated oxidation-wet etching cycles.
Real-Time Estimation of Pathological Tremor Parameters from Gyroscope Data
José L. Pons
2010-03-01
Full Text Available This paper presents a two stage algorithm for real-time estimation of instantaneous tremor parameters from gyroscope recordings. Gyroscopes possess the advantage of providing directly joint rotational speed, overcoming the limitations of traditional tremor recording based on accelerometers. The proposed algorithm first extracts tremor patterns from raw angular data, and afterwards estimates its instantaneous amplitude and frequency. Real-time separation of voluntary and tremorous motion relies on their different frequency contents, whereas tremor modelling is based on an adaptive LMS algorithm and a Kalman filter. Tremor parameters will be employed to drive a neuroprosthesis for tremor suppression based on biomechanical loading.
Modeling and Simulation of MOEMS Gyroscope Based on TE-TM Mode Converter
ZHAO Yi; CHEN Shu-fen
2009-01-01
A novel structure design of micro optic electro mechanical system (MOEMS) gyroscope is presented in this paper. The structure combining surface acoustic wave (SAW) sensor, optical waveguide diffractive component, electro-optical modulator etc. is integrated on a LiNbO3 substrate as the gyroscope for sensing rotating angular velocity, and an optical readout device is added on the traditional SAW typed TE-TM mode converter as the detecting device. The principles of the MOEMS are discussed in the paper, and simulation result shows that there would be apparent advantages of higher precision and stronger anti-vibration capacity.
Gyroscope vs. accelerometer measurements of motion from wrist PPG during physical exercise
Alexander J. Casson
2016-12-01
Full Text Available Many wearable devices include PPG (photoplethysmography sensors for non-invasive heart rate monitoring. However, PPG signals are heavily corrupted by motion interference, and rely on simultaneous motion measurements to remove the interference. Accelerometers are used commonly, but cannot differentiate between acceleration due to movement and acceleration due to gravity. This paper compares measurements of motion using accelerometers and gyroscopes to give a more complete estimate of wrist motion. Results show the two sensor signals are very different, with low correlations present. When used in a wrist PPG heart rate algorithm gyroscope motion estimates obtain better performance in half of the cases.
Techniques for searching first integrals by Lie group and application to gyroscope system
HU Yanxia; GUAN Keying
2005-01-01
In the paper, the methods of finding first integrals of an autonomous system using one-parameter Lie groups are discussed. A class of nontrivial one-parameter Lie groups admitted by the classical gyroscope system is found, and based on the properties of first integral determined by the one-parameter Lie group, the fourth first integral of the gyroscope system in Euler case, Lagrange case and Kovalevskaya case can be obtained in a uniform idea. An error on the fourth first integral in general Kovalevskaya case (A=B=2C,zG=0), which appeared in literature is found and corrected.
Low-Loss Polymer-Based Ring Resonator for Resonant Integrated Optical Gyroscopes
Guang Qian
2014-01-01
Full Text Available Waveguide ring resonator is the sensing element of resonant integrated optical gyroscope (RIOG. This paper reports a polymer-based ring resonator with a low propagation loss of about 0.476 dB/cm for RIOG. The geometrical parameters of the waveguide and the coupler of the resonator were optimally designed. We also discussed the optical properties and gyroscope performance of the polymer resonator which shows a high quality factor of about 105. The polymer-based RIOG exhibits a limited sensitivity of less than 20 deg/h for the low and medium resolution navigation systems.
Venediktov, V Yu [Department of Physics, St. Petersburg State University, St. Petersburg (Russian Federation); Filatov, Yu V; Shalymov, E V [St. Petersburg Electrotechnical University " LETI" , St. Petersburg (Russian Federation)
2014-12-31
The prototype schemes of a microoptical gyroscope (MOG) developed to date on the basis of passive ring cavities imply the use of the amplitude characteristic only, since they operate using the dip in the transmission coefficient. We have analysed the possibility of creating a MOG, in which the phase characteristic is used as well. The phase characteristic of a ring interferometer has distinctive features in the vicinity of the cavity eigenfrequencies, which may be used to determine the angular velocity. A method for the angular velocity determination using both the phase and the amplitude characteristics of the interferometer is considered. (laser gyroscopes)
On-chip tunable dispersion in a ring laser gyroscope for enhanced rotation sensing
Zhang, Hao; Liu, Jiaming; Lin, Jian; Li, Wenxiu; Xue, Xia; Huang, Anping; Xiao, Zhisong
2016-05-01
A gyroscope structure with tailored local dispersion profile to enhance sensitivity is proposed, which uses lithium niobate (LiNbO3) thin film as the on-chip material of gyroscope's resonator. A Mach-Zehnder interferometer (MZI) structure as a coupler, which induces a different reference phase shift in each arm, is inserted into the position between ring resonator and output bus waveguide. Through modulating reference phase shift in MZI, theoretical rotation sensitivity enhancement as large as one order of magnitude is presented.
The Use of Accelerometers and Gyroscopes to Estimate Hip and Knee Angles on Gait Analysis
Francesco Alonge
2014-05-01
Full Text Available In this paper the performance of a sensor system, which has been developed to estimate hip and knee angles and the beginning of the gait phase, have been investigated. The sensor system consists of accelerometers and gyroscopes. A new algorithm was developed in order to avoid the error accumulation due to the gyroscopes drift and vibrations due to the ground contact at the beginning of the stance phase. The proposed algorithm have been tested and compared to some existing algorithms on over-ground walking trials with a commercial device for assisted gait. The results have shown the good accuracy of the angles estimation, also in high angle rate movement.
Relational experiences of partnered Japanese immigrant women with affect disorders.
Kozuki, Yoriko; Kennedy, Michael G; Tsai, Jenny Hsin-Chun
2006-03-01
This paper reports the findings of a study that explored characteristics of relationships of Japanese immigrant women partnered both intraculturally and interculturally, and analysed the role of Japanese culture in these relationships. Immigration can cause shifts in interpersonal structures with partners. When there are large discrepancies in gender roles and communication styles between the original and host cultures, the psychological impact on both partners may be significant. However, currently no empirical data are available to support this assumption. Ten cases selected from the 68 medical records of Japanese-speaking women seen at a mental health clinic from September 2001 to September 2004 were analysed. All of the 10 women met DSM IV-TR criteria of major depressive disorder and were taking antidepressants. Half of the 10 women were in intimate intercultural partnered relationships and the remainder of the matched cases were in intracultural relationships at the time of treatment. The two cohorts were matched in age (36.2 and 43.2 years), length of stay in the United States of America (12 and 16.2 years), and length of treatment (1.2 and 1 years). The length of time of the sample in individual psychodynamic psychotherapy ranged from 20 to 317 hours, depending on the intensity of therapy. Inductive data analysis revealed two themes: (1) Lack of awareness of differences in culturally bound communication by Japanese women in intercultural partnerships; (2) Lack of individuality in Japanese women in intracultural partnerships. Neither group appeared to consider relational aspects of partnership, or to make efforts to improve direct communication with their partners. The influence of Japanese culture on gender role and communication styles functions contrary to the mainstream Western culture of the United States of America. In the future, interpersonal elements of cultural differences between host and original cultures in immigration should be considered in
Special relativity effects for space-based coherent lidar experiments
Raogudimetla, V. S.
1994-01-01
There is a great need to develop a system that can measure accurately atmospheric wind profiles because an accurate data of wind profiles in the atmosphere constitutes single most input for reliable simulations of global climate numerical methods. Also such data helps us understand atmospheric circulation and climate dynamics better. Because of this need for accurate wind measurements, a space-based Laser Atmospheric Winds Sounder (LAWS) is being designed at MSFC to measure wind profiles in the lower atmosphere of the earth with an accuracy of 1 m/s at lower altitudes to 5m/s at higher altitudes. This system uses an orbiting spacecraft with a pulsed laser source and measures the Doppler shift between the transmitted and received frequencies to estimate the atmospheric wind velocities. If a significant return from the ground (sea) is possible, the spacecraft speed and height are estimated from it and these results and the Doppler shift are then used to estimate the wind velocities in the atmosphere. It is expected that at the proposed wavelengths, there will be enough backscatter from the aerosols but there may no be significant return from the ground. So a coherent (heterodyne) detection system is being proposed for signal processing because it can provide high signal to noise ratio and sensitivity and thus make the best use of low ground return. However, for a heterodyne detection scheme to provide the best results, it is important that the receiving aperture be aligned properly for the proposed wind sounder, this amounts to only a few microradians tolerance in alignment. It is suspected that the satellite motion relative to the ground may introduce errors in the order of a few microradians because of special relativity. Hence, the problem of laser scattering off a moving fixed target when the source and receiver are moving, which was not treated in the past in the literature, was analyzed in the following, using relativistic electrodynamics and applied to the
Causality, relativity and quantum correlation experiments with moving reference frames
H Zbinden; J Brendel; W Tittel; N Gisin
2001-02-01
Entanglement, one of the most important features of quantum mechanics, is at the core of the famous Einstein–Bohr philosophical debate [1] and is the principal resource for quantum information processing [2]. We report on new experimental investigations of the properties of entangled photon pairs with emphasis on the tension between quantum mechanics and relativity [3,4]. Entangled photons are sent via an optical ﬁber network to two villages near Geneva, separated by more than 10 km where they are analyzed by interferometers [5]. The photon pair source is set as precisely as possible in the center so that the two photons arrive at the detectors within a time interval of less than 5 ps (corresponding to a path length difference of less than 1 mm). This sets a lower bound on the ‘speed of quantum information’ to 107 times the speed of light. Next, one detector is set in motion [6] so that both detectors, each in its own inertial reference frame, are ﬁrst to do the measurement! The data always reproduces the quantum correlations.
Life Experience with Death: Relation to Death Attitudes and to the Use of Death-Related Memories
Bluck, Susan; Dirk, Judith; Mackay, Michael M.; Hux, Ashley
2008-01-01
The study examines the relation of death experience to death attitudes and to autobiographical memory use. Participants (N = 52) completed standard death attitude measures and wrote narratives about a death-related autobiographical memory and (for comparison) a memory of a low point. Self-ratings of the memory narratives were used to assess their…
Developments in Pursuit of a Micro-Optic Gyroscope
VAWTER, GREGORY A.; ZUBRZYCKI, WALTER J.; PEAKE, GREGORY M.; ALFORD, CHARLES; HARGETT, TERRY; SALTERS, BETTY; HUDGENS, JAMES J.; KINNEY, RAGON D.
2003-03-01
have developed the photonic elements necessary for a resonant micro-optical gyro. We individually designed an AlGaAs distributed Bragg reflector laser; GaAs phase modulator and GaAs photodiode detector. Furthermore, we have fabricated a breadboard gyroscope, which was used to confirm modeling and evaluate signal processing and control circuits.
Watson, D
2001-11-01
The author examined the associations among sleep-related experiences (e.g., hypnagogic hallucinations, nightmares, waking dreams, and lucid dreams), dissociation, schizotypy, and the Big Five personality traits in 2 large student samples. Confirmatory factor analyses indicated that (a) dissociation and schizotypy are strongly correlated-yet distinguishable-constructs, and (b) the differentiation between them can be enhanced by eliminating detachment/depersonalization items from the dissociation scales. A general measure of sleep experiences was substantially correlated with both schizotypy and dissociation (especially the latter) and more weakly related to the Big Five. In contrast, an index of lucid dreaming was weakly related to all of these other scales. These results suggest that measures of dissociation, schizotypy, and sleep-related experiences all define a common domain characterized by unusual cognitions and perceptions.
Song, O; Jeong, N H; Librescu, L
2001-03-01
Problems related with the implications of conservative and gyroscopic forces on vibration and the stability of a circular cylindrical shaft modeled as a thin-walled composite beam and spinning with constant angular speed about its longitudinal axis are addressed. Taking into account the directionality property of fiber reinforced composite materials, it is shown that for a shaft featuring flapwise-chordwise-bending coupling, a dramatic enhancement of both the vibrational and stability behavior can be reached. In addition, the effects played in the same context by transverse shear, rotatory inertias as well as by the various boundary conditions are discussed and pertinent conclusions are outlined.
Experience-Based Mitigation of Age-Related Performance Declines: Evidence from Air Traffic Control
Nunes, Ashley; Kramer, Arthur F.
2009-01-01
Previous research has found age-related deficits in a variety of cognitive processes. However, some studies have demonstrated age-related sparing on tasks where individuals have substantial experience, often attained over many decades. Here, the authors examined whether decades of experience in a fast-paced demanding profession, air traffic…
Modeling the Spin Motor Current of the International Space Station's Control Moment Gyroscopes
Pereira, Miguel A.
2008-01-01
The International Space Station (ISS) attitude control is provided by two means: The Russian Segment uses thrusters and the U.S. Segment uses double-gimbaled control moment gyroscopes (CMG). CMGs are used as momentum exchange devices, providing non propulsive attitude control for the vehicle. The CMGs are very important for the ISS program because, first, they save propellant - which needs to be transferred to the Station in special cargo vehicles - and, second, they provide the microgravity environment on the Station - which is necessary for scientific experiments planned for the ISS mission. Since 2002, when one of the CMG on the ISS failed, all CMGs are closely monitored. High gimbal rates, vibration spikes, unusual variations of spin motor current and bearing temperatures are of great concern, since these parameters are the CMG health indicators. The telemetry analysis of these and some other CMG parameters is used to determine constrains and make changes to the CMGs operation on board. These CMG limitations, in turn, may limit the ISS attitude control capabilities and may be critical to ISS operation. Therefore, it is important to know whether the CMG parameter is nominal or out of family, and why. The goal of this project is to analyze an important CMG parameter - spin motor current. Some operational decisions are made now based on the spin motor current signatures. The spin motor current depends on gimbal rates, ISS rates, and spin bearing friction. The spin bearing friction in turn depends on the bearing temperatures, wheel rates, normal load - which is a function of gimbal and wheel rates - lubrication, etc. The first task of this project is to create a spin motor current mathematical model based on CMG dynamics model and the current knowledge on bearing friction in microgravity.
Modeling the Spin Motor Current of the International Space Station's Control Moment Gyroscopes
Pereira, Miguel A.
2008-01-01
The International Space Station (ISS) attitude control is provided by two means: The Russian Segment uses thrusters and the U.S. Segment uses double-gimbaled control moment gyroscopes (CMG). CMGs are used as momentum exchange devices, providing non propulsive attitude control for the vehicle. The CMGs are very important for the ISS program because, first, they save propellant - which needs to be transferred to the Station in special cargo vehicles - and, second, they provide the microgravity environment on the Station - which is necessary for scientific experiments planned for the ISS mission. Since 2002, when one of the CMG on the ISS failed, all CMGs are closely monitored. High gimbal rates, vibration spikes, unusual variations of spin motor current and bearing temperatures are of great concern, since these parameters are the CMG health indicators. The telemetry analysis of these and some other CMG parameters is used to determine constrains and make changes to the CMGs operation on board. These CMG limitations, in turn, may limit the ISS attitude control capabilities and may be critical to ISS operation. Therefore, it is important to know whether the CMG parameter is nominal or out of family, and why. The goal of this project is to analyze an important CMG parameter - spin motor current. Some operational decisions are made now based on the spin motor current signatures. The spin motor current depends on gimbal rates, ISS rates, and spin bearing friction. The spin bearing friction in turn depends on the bearing temperatures, wheel rates, normal load - which is a function of gimbal and wheel rates - lubrication, etc. The first task of this project is to create a spin motor current mathematical model based on CMG dynamics model and the current knowledge on bearing friction in microgravity.
Novel Kalman filtering algorithmfor virtual gyroscop%虚拟陀螺改进卡尔曼滤波设计
吕琦炜; 鲍其莲
2015-01-01
本文针对提高低精度微陀螺精度的问题展开研究，基于陀螺阵列的虚拟陀螺技术，利用滤波补偿算法，将多个具有相似特性的低精度陀螺组成陀螺阵列，提出改进的卡尔曼滤波算法将多个陀螺的输出进行数据融合，构成虚拟陀螺，并利用多陀螺数据间的相关性，对误差进行补偿消除。仿真实验结果表明，所构成的虚拟陀螺其估计残差比单陀螺减小80%以上。%This paper focuses on virtual gyroscope technology based algorithms. In order to improve accuracy of MEMS gyroscope, a virtual gyroscope system based on multiple MEMS gyroscopes is designed. A novel improved Kalman filtering algorithm is presented to integrated the outputs of those MEMS gyroscopes. The simulation results show that the presented virtual gyroscope can reduce 80%of the output error comparing to a single gyroscope.
Aono, T.; Suzuki, K.; Kanamaru, M.; Okada, R.; Maeda, D.; Hayashi, M.; Isono, Y.
2016-10-01
This research demonstrates a newly developed anodic bonding-based wafer-level-packaging technique to simultaneously seal an accelerometer in the atmosphere and a gyroscope in a vacuum with a glass cap for micro-electromechanical systems sensors. It is necessary for the accelerometer, with a damping oscillator, to be sealed in the atmosphere to achieve a high-speed response. As the gyroscope can achieve high sensitivity with a large displacement at the resonant frequency without air-damping, the gyroscope must be sealed in a vacuum. The technique consists of three processing steps: the first bonding step in the atmosphere for the accelerometer, the pressure control step and the second bonding step in a vacuum for the gyroscope. The process conditions were experimentally determined to achieve higher shear strength at the interface of the packaging. The packaging performance of the accelerometer and gyroscope after wafer-level packaging was also investigated using a laser Doppler velocimeter at room temperature. The amplitude at the resonant frequency of the accelerometer was reduced by air damping, and the quality factor of the gyroscope showed a value higher than 1000. The reliability of the gyroscope was also confirmed by a thermal cyclic test and an endurance test at high humidity and high temperature.
Svetoslav Ganchev Nikolov
2015-07-01
Full Text Available The study of the dynamic behavior of a rigid body with one fixed point (gyroscope has a long history. A number of famous mathematicians and mechanical engineers have devoted enormous time and effort to clarify the role of dynamic effects on its movement (behavior – stable, periodic, quasi-periodic or chaotic. The main objectives of this review are: 1 to outline the characteristic features of the theory of dynamical systems and 2 to reveal the specific properties of the motion of a rigid body with one fixed point (gyroscope.This article consists of six sections. The first section addresses the main concepts of the theory of dynamical systems. Section two presents the main theoretical results (obtained so far concerning the dynamic behavior of a solid with one fixed point (gyroscope. Section three examines the problem of gyroscopic stabilization. Section four deals with the non-linear (chaotic dynamics of the gyroscope. Section five is a brief analysis of the gyroscope applications in engineering. The final section provides conclusions and generalizations on why the theory of dynamical systems should be used in the study of the movement of gyroscopic systems.
A universal gyroscope driving circuit with 70dB amplitude control range
Abdelghany, Mohamed A.
2010-08-01
A CMOS variable gain driving circuit with output signal amplitude control for gyroscopes with wide range of quality factors is presented. The driving circuit can be used for gyroscopes with Q values higher than 500. The circuit uses a current-commutating switching mixer to control the gyroscope driving signal level. Conventional driving circuits use automatic gain control (AGC) which suffers from limited linear range and the need for an off-chip capacitor for the peak detector and loop filter. Two stage variable gain amplifier is used in the proposed design to ensure enough gain for oscillation for such a wide range of quality factors. Analog and digital amplitude control methods are used to cover wide range of driving signal amplitude with enough accuracy to hit the maximum driving signal level without sacrificing gyroscope linearity. Due to the high DC gain of the amplifier chain, DC offset resulting from mismatches might saturate the amplifier output. DC offset correction is employed using a secondary negative feedback loop. The proposed driving circuit is being fabricated in 0.6μm CMOS technology. © 2010 IEEE.
Sadaghzadeh N, Nargess; Poshtan, Javad; Wagner, Achim; Nordheimer, Eugen; Badreddin, Essameddin
2014-03-01
Based on a cascaded Kalman-Particle Filtering, gyroscope drift and robot attitude estimation method is proposed in this paper. Due to noisy and erroneous measurements of MEMS gyroscope, it is combined with Photogrammetry based vision navigation scenario. Quaternions kinematics and robot angular velocity dynamics with augmented drift dynamics of gyroscope are employed as system state space model. Nonlinear attitude kinematics, drift and robot angular movement dynamics each in 3 dimensions result in a nonlinear high dimensional system. To reduce the complexity, we propose a decomposition of system to cascaded subsystems and then design separate cascaded observers. This design leads to an easier tuning and more precise debugging from the perspective of programming and such a setting is well suited for a cooperative modular system with noticeably reduced computation time. Kalman Filtering (KF) is employed for the linear and Gaussian subsystem consisting of angular velocity and drift dynamics together with gyroscope measurement. The estimated angular velocity is utilized as input of the second Particle Filtering (PF) based observer in two scenarios of stochastic and deterministic inputs. Simulation results are provided to show the efficiency of the proposed method. Moreover, the experimental results based on data from a 3D MEMS IMU and a 3D camera system are used to demonstrate the efficiency of the method.
Using a MEMS gyroscope to measure the Earth’s rotation for gyrocompassing applications
Iozan, L. I.; Kirkko-Jaakkola, M.; Collin, J.; Takala, J.; Rusu, C.
2012-02-01
In this paper, a method and system for gyrocompassing based on a low-cost micro-electro-mechanical (MEMS) gyroscope are described. The proposed setup is based on the choice of a gyroscope with specified bias instability better than 2 deg h-1 and on careful error compensation. The gyroscope is aligned parallel to the local level, which helps to eliminate the g-sensitivity effect but also sacrifices a fraction of the Earth’s rotation rate that can be observed. The additive bias is compensated for by rotating the sensor mechanically and by extended Kalman filtering. In this paper, it is demonstrated that the proposed system is capable of observing the Earth’s rotation, and the north finding results show that a two-sigma accuracy of 4.03° was attained at latitude 61°N. With current MEMS gyroscopes, the system requires hours of time to achieve this accuracy, but the results demonstrate the theoretical accuracy potential of these small self-contained, low-cost sensors.
An Adaptive Fuzzy Control Approach for the Robust Tracking of a MEMS Gyroscope Sensor
Juntao Fei
2011-11-01
Full Text Available In this paper, a direct adaptive fuzzy control using a supervisory compensator is designed for the robust tracking of a MEMS gyroscope sensor. The parameters of the membership functions are adjusted according to the designed adaptive law for the purpose of tracking a reference trajectory. A fuzzy controller that can approximate the unknown nonlinear function and compensate the system
Application of MEMS Accelerometers and Gyroscopes in Fast Steering Mirror Control Systems.
Tian, Jing; Yang, Wenshu; Peng, Zhenming; Tang, Tao; Li, Zhijun
2016-03-25
In a charge-coupled device (CCD)-based fast steering mirror (FSM) tracking control system, high control bandwidth is the most effective way to enhance the closed-loop performance. However, the control system usually suffers a great deal from mechanical resonances and time delays induced by the low sampling rate of CCDs. To meet the requirements of high precision and load restriction, fiber-optic gyroscopes (FOGs) are usually used in traditional FSM tracking control systems. In recent years, the MEMS accelerometer and gyroscope are becoming smaller and lighter and their performance have improved gradually, so that they can be used in a fast steering mirror (FSM) to realize the stabilization of the line-of-sight (LOS) of the control system. Therefore, a tentative approach to implement a CCD-based FSM tracking control system, which uses MEMS accelerometers and gyroscopes as feedback components and contains an acceleration loop, a velocity loop and a position loop, is proposed. The disturbance suppression of the proposed method is the product of the error attenuation of the acceleration loop, the velocity loop and the position loop. Extensive experimental results show that the MEMS accelerometers and gyroscopes can act the similar role as the FOG with lower cost for stabilizing the LOS of the FSM tracking control system.
Abedi, Maryam; Jin, Tian; Sun, Kewen
2015-08-31
In this paper, the efficiency of the gyroscopic mounting method is studied for a highly dynamic GNSS receiver's reference oscillator for reducing signal loss. Analyses are performed separately in two phases, atmospheric and upper atmospheric flights. Results show that the proposed mounting reduces signal loss, especially in parts of the trajectory where its probability is the highest. This reduction effect appears especially for crystal oscillators with a low elevation angle g-sensitivity vector. The gyroscopic mounting influences frequency deviation or jitter caused by dynamic loads on replica carrier and affects the frequency locked loop (FLL) as the dominant tracking loop in highly dynamic GNSS receivers. In terms of steady-state load, the proposed mounting mostly reduces the frequency deviation below the one-sigma threshold of FLL (1σ(FLL)). The mounting method can also reduce the frequency jitter caused by sinusoidal vibrations and reduces the probability of signal loss in parts of the trajectory where the other error sources accompany this vibration load. In the case of random vibration, which is the main disturbance source of FLL, gyroscopic mounting is even able to suppress the disturbances greater than the three-sigma threshold of FLL (3σ(FLL)). In this way, signal tracking performance can be improved by the gyroscopic mounting method for highly dynamic GNSS receivers.
Efficiency of a gyroscopic device for conversion of mechanical wave energy to electrical energy
Carlsen, Martin; Darula, Radoslav; Gravesen, Jens;
2011-01-01
We consider a recently proposed gyroscopic device for conversion of mechanical ocean wave energy to electrical energy. Two models of the device derived from standard engineering mechanics from the literature are analysed, and a model is derived from analytical mechanics considerations. From...
Analysis of Drift Errors in the JPL/UCLA Micromachined Gyroscope
Chakraborty, I.
1996-01-01
The model of the JPL/UCLA micromachined vibratory gyroscope will be enhanced to include time varying effects. First, they will be shown to exist through trends in the experimental results. Causes of mechanical error will be further explained by analyzing possible perturbations to the physical model.
Acar, Cenk; Shkel, Andrei M.
2002-07-01
This paper reports a design concept for MEMS gyroscopes that shifts the complexity of the design from control architecture to system dynamics, utilizing the passive disturbance rejection capability of the 4-DOF dynamical system. Specifically, a novel wide-bandwidth micromachined gyroscope design approach based on increasing the degrees-of-freedom of the oscillatory system by the use of two independently oscillating interconnected proof masses is presented along with preliminary experimental demonstration of implementation feasibility. With the concept of using a 4-DOF system, inherent disturbance rejection is achieved due to the wide operation frequency range of the dynamic system, providing reduced sensitivity to structural and thermal parameter fluctuations. Thus, less demanding active control strategies are required for operation under presence of perturbations. The fabricated prototype dual-mass gyroscopes successfully demonstrated a dramatically wide driving frequency range within where the drive direction oscillation amplitude varies insignificantly without any active control, in contrast to the conventional gyroscopes where the mass has to be sustained in constant amplitude oscillation in a very narrow frequency band. Mechanical amplification of driven mass oscillation by the sensing element was also experimentally demonstrated, providing large oscillation amplitudes, which is crucial for sensor performance.
Identification of Error Sources in High Precision Weight Measurements of Gyroscopes
Lőrincz, I
2015-01-01
A number of weight anomalies have been reported in the past with respect to gyroscopes. Much attention was gained from a paper in Physical Review Letters, when Japanese scientists announced that a gyroscope loses weight up to $0.005\\%$ when spinning only in the clockwise rotation with the gyroscope's axis in the vertical direction. Immediately afterwards, a number of other teams tried to replicate the effect, obtaining a null result. It was suggested that the reported effect by the Japanese was probably due to a vibration artifact, however, no final conclusion on the real cause has been obtained. We decided to build a dedicated high precision setup to test weight anomalies of spinning gyroscopes in various configurations. A number of error sources like precession and vibration and the nature of their influence on the measurements have been clearly identified, which led to the conclusive explanation of the conflicting reports. We found no anomaly within $\\Delta m/m<2.6 \\times 10^{-6}$ valid for both horizon...
Decoupling Control of Micromachined Spinning-Rotor Gyroscope with Electrostatic Suspension.
Sun, Boqian; Wang, Shunyue; Li, Haixia; He, Xiaoxia
2016-10-20
A micromachined gyroscope in which a high-speed spinning rotor is suspended electrostatically in a vacuum cavity usually functions as a dual-axis angular rate sensor. An inherent coupling error between the two sensing axes exists owing to the angular motion of the spinning rotor being controlled by a torque-rebalance loop. In this paper, a decoupling compensation method is proposed and investigated experimentally based on an electrostatically suspended micromachined gyroscope. In order to eliminate the negative spring effect inherent in the gyroscope dynamics, a stiffness compensation scheme was utilized in design of the decoupled rebalance loop to ensure loop stability and increase suspension stiffness. The experimental results show an overall stiffness increase of 30.3% after compensation. A decoupling method comprised of inner- and outer-loop decoupling compensators is proposed to minimize the cross-axis coupling error. The inner-loop decoupling compensator aims to attenuate the angular position coupling. The experimental frequency response shows a position coupling attenuation by 14.36 dB at 1 Hz. Moreover, the cross-axis coupling between the two angular rate output signals can be attenuated theoretically from -56.2 dB down to -102 dB by further appending the outer-loop decoupling compensator. The proposed dual-loop decoupling compensation algorithm could be applied to other dual-axis spinning-rotor gyroscopes with various suspension solutions.
On gyroscopic effects in vibrating and axially rotating solid and annular discs
Joubert, SV
2007-05-01
Full Text Available , such as cylindrical, hemispherical and planar circular disc rotational sensors. The model of a thin circular disc vibrating in its plane and subjected to inertial rotation is considered. The dynamics of the disc gyroscope are considered in terms of linear elasticity...
Analysis and design of the system of a total digital Si-gyroscope
Huang, Fuxiang; Liang, Yin
2017-03-01
In order to get a thorough understanding of the total digital silicon micro-gyroscope, a novel system-level model with details of both the sense and circuit is presented in this paper. Unlike the traditional structures of the digital part of the digital gyroscope, a structure with programmable delay units (PDUs) instead of DPLLs gives a brief and robust character of the whole system. And the PDUs coordinating with the FIR filter could lead to a removal of the IF filters of the sigma-delta DAC for feedback, which saves a lot of consumption. Two MASH sigma-delta ADCs are designed to convert the output of the charge-voltage converters to digital signals, which also bring a better stability. The ADCs achieve an SNR of 102.5 dB with a 10 kHz bandwidth. The stabilization of the closed drive mode has also been analyzed including how the noise caused by the quantization of the digital circuit is affecting the stabilization of both the amplitude and frequency of the driving signals. In the end, a final result of simulation of the gyroscope shows the correctness and accuracy of the whole model of the gyroscope.
Application of MEMS Accelerometers and Gyroscopes in Fast Steering Mirror Control Systems
Jing Tian
2016-03-01
Full Text Available In a charge-coupled device (CCD-based fast steering mirror (FSM tracking control system, high control bandwidth is the most effective way to enhance the closed-loop performance. However, the control system usually suffers a great deal from mechanical resonances and time delays induced by the low sampling rate of CCDs. To meet the requirements of high precision and load restriction, fiber-optic gyroscopes (FOGs are usually used in traditional FSM tracking control systems. In recent years, the MEMS accelerometer and gyroscope are becoming smaller and lighter and their performance have improved gradually, so that they can be used in a fast steering mirror (FSM to realize the stabilization of the line-of-sight (LOS of the control system. Therefore, a tentative approach to implement a CCD-based FSM tracking control system, which uses MEMS accelerometers and gyroscopes as feedback components and contains an acceleration loop, a velocity loop and a position loop, is proposed. The disturbance suppression of the proposed method is the product of the error attenuation of the acceleration loop, the velocity loop and the position loop. Extensive experimental results show that the MEMS accelerometers and gyroscopes can act the similar role as the FOG with lower cost for stabilizing the LOS of the FSM tracking control system.
Monaghan, C.C.; Riel, W.J.B.M.; Veltink, P.H.
2009-01-01
This article presents a stimulation control method using a uniaxial gyroscope measuring angular velocity of the shank in the sagittal plane, to control functional electrical stimulation of the triceps surae to improve push-off of stroke subjects during gait. The algorithm is triggered during each sw
The kinematics of the swing phase obtained from accelerometer and gyroscope measurements
Heyn, Andreas; Mayagoitia, Ruth E.; Nene, Anand V.; Veltink, Peter H.
1996-01-01
The kinematics needed to calculate the knee moment during the initial swing phase were obtained from a set of eight leg-mounted uni-axial accelerometers and two gyroscopes. The angular and linear accelerations of shank and thigh were calculated from the signals of two accelerometers mounted on each
Mechanical Coupling Error Suppression Technology for an Improved Decoupled Dual-Mass Micro-Gyroscope
Bo Yang
2016-04-01
Full Text Available This paper presents technology for the suppression of the mechanical coupling errors for an improved decoupled dual-mass micro-gyroscope (DDMG. The improved micro-gyroscope structure decreases the moment arm of the drive decoupled torque, which benefits the suppression of the non-ideal decoupled error. Quadrature correction electrodes are added to eliminate the residual quadrature error. The structure principle and the quadrature error suppression means of the DDMG are described in detail. ANSYS software is used to simulate the micro-gyroscope structure to verify the mechanical coupling error suppression effect. Compared with the former structure, simulation results demonstrate that the rotational displacements of the sense frame in the improved structure are substantially suppressed in the drive mode. The improved DDMG structure chip is fabricated by the deep dry silicon on glass (DDSOG process. The feedback control circuits with quadrature control loops are designed to suppress the residual mechanical coupling error. Finally, the system performance of the DDMG prototype is tested. Compared with the former DDMG, the quadrature error in the improved dual-mass micro-gyroscope is decreased 9.66-fold, and the offset error is decreased 6.36-fold. Compared with the open loop sense, the feedback control circuits with quadrature control loop decrease the bias drift by 20.59-fold and the scale factor non-linearity by 2.81-fold in the ±400°/s range.
Yang, Bo; Wang, Xingjun; Deng, Yunpeng; Hu, Di
2016-01-01
This paper presents technology for the suppression of the mechanical coupling errors for an improved decoupled dual-mass micro-gyroscope (DDMG). The improved micro-gyroscope structure decreases the moment arm of the drive decoupled torque, which benefits the suppression of the non-ideal decoupled error. Quadrature correction electrodes are added to eliminate the residual quadrature error. The structure principle and the quadrature error suppression means of the DDMG are described in detail. ANSYS software is used to simulate the micro-gyroscope structure to verify the mechanical coupling error suppression effect. Compared with the former structure, simulation results demonstrate that the rotational displacements of the sense frame in the improved structure are substantially suppressed in the drive mode. The improved DDMG structure chip is fabricated by the deep dry silicon on glass (DDSOG) process. The feedback control circuits with quadrature control loops are designed to suppress the residual mechanical coupling error. Finally, the system performance of the DDMG prototype is tested. Compared with the former DDMG, the quadrature error in the improved dual-mass micro-gyroscope is decreased 9.66-fold, and the offset error is decreased 6.36-fold. Compared with the open loop sense, the feedback control circuits with quadrature control loop decrease the bias drift by 20.59-fold and the scale factor non-linearity by 2.81-fold in the ±400°/s range.
Analysis of the Gyroscopic Stabilization of a System of Rigid Bodies
Kliem, Wolfhard
1996-01-01
We study the gyroscopic of a three-body system. A new method offinding stability regions, based on mechanism and criteria for gyroscopicstabilization, is presented. Of particular interest in this connection isthe theory of interaction of eigenvalues. This leads to a complete 3-dimensionalanalysis...
Modeling and Simulation of Non-idealities in a Z-axis CMOS-MEMS Gyroscope
2003-04-01
Analog Hardware Description Language ( AHDL ) model implementation of mechanical second-order systems, such as the resonating structure in a gyroscope. AHDL ... AHDL ) was obtained by extend- ing time-discretized interpretation of electrical components such as resistors, inductors and capacitors to the...mechanical domain. Pointers for AHDL implementation with better simulation convergence and speed were deduced. Important guidelines to be considered during
Mayagoitia, Ruth E.; Nene, Anand V.; Veltink, Peter H.
2002-01-01
A general-purpose system to obtain the kinematics of gait in the sagittal plane based on body-mounted sensors was developed. It consisted of four uniaxial seismic accelerometers and one rate gyroscope per body segment. Tests were done with 10 young healthy volunteers, walking at five different speed
A new cantilever beam-rigid-body MEMS gyroscope: mathematical model and linear dynamics
Lajimi, Seyed Amir Mousavi; Abdel-Rahman, Eihab
2014-01-01
A new microbeam-rigid-body gyroscope is introduced and its static and dynamic behaviours are studied. The main structure includes a microbeam and an eccentric end-rigid-body influencing the dynamic and static characteristics of the sensor. The sensitivity of the device and the effect of system parameters on the microsystem's response are investigated.
van der Werf, Christian; Onderwater, Astrid T.; van Langen, Irene M.; Smets, Ellen M. A.
2014-01-01
Relatives of young sudden cardiac death (SCD) victims are at increased risk of carrying a potentially fatal inherited cardiac disease. Hence, it is recommended to perform an autopsy on the victim and to refer his or her relatives to a cardiogenetics clinic for a full evaluation to identify those at
Relation of tolerance of ambiguity to global and specific paranormal experience.
Houran, J; Williams, C
1998-12-01
We examined the relationship of tolerance of ambiguity to severe global factors and specific types of anomalous or paranormal experience. 107 undergraduate students completed MacDonald's 1970 AT-20 and the Anomalous Experiences Inventory of Kumar, Pekala, and Gallagher. Scores on the five subscales of the Anomalous Experiences Inventory correlated differently with tolerance of ambiguity. Global paranormal beliefs, abilities, experiences, and drug use were positively associated with tolerance of ambiguity, whereas a fear of paranormal experience showed a negative relation. The specific types of anomalous experiences that correlated with tolerance of ambiguity often involved internal or physiological experience, e.g., precognitive dreams, memories of reincarnation, visual apparitions, and vestibular alterations. We generally found no effects of age of sex. These results are consistent with the idea that some paranormal experiences are misattributions of internal experience to external ('paranormal') sources, a process analogous to mechanisms underpinning delusions and hallucinations.
On the Late Development and Possible Astronomical Origin of the Gyroscope
Brecher, Kenneth
2013-01-01
The invention of the gyroscope is usually attributed to the French physicist Jean-Bernard-Leon Foucault in the year 1852. He certainly created the word and also used his gyroscope to demonstrate the rotation of the Earth. However, the gyroscope was actually invented around 1812 by the German scientist Johann Bohnenberger who called his device simply the “machine”. Bohnenberger was a professor of astronomy and mathematics and published a book about astronomy in 1811. Several other scientists, including American physicist Walter R. Johnson (who called his apparatus the “rotascope”), independently invented the gyroscope. Each of these devices employed a central object (sphere or disc) that could spin on a shaft. This object was placed between three independent gimbals, two of which could move freely. Bohnenberger’s “machine” has much the same appearance as an armillary sphere. Those astronomical devices had been produced for at least the preceding three centuries and were widely dispersed and well known throughout Europe. They were used to display the apparent motion of celestial bodies. However, armillary spheres were used only as simulations of celestial appearances, not as actual demonstrations of physical phenomena. It is not known if the inertial properties of armillary spheres (and also of terrestrial and celestial globes) had been studied before about 1800. Nonetheless, as a matter of practice, gimbal systems similar to those found in gyroscopes were used on ships to level oil lamps at least as early as the sixteenth century AD. And the ideas behind armillary spheres date back at least a millennium before that. So why did the invention of the gyroscope in its modern form take such a long time when the individual underlying components had been around and utilized for some two millennia? Perhaps because the understanding of angular momentum, including its conservation, was not developed until the start of the 19th century and also because the
MEMS微陀螺仪研究进展%Research Development of MEMS Micro-Gyroscopes
成宇翔; 张卫平; 陈文元; 崔峰; 刘武; 吴校生
2011-01-01
回顾了MEMS微陀螺仪的研究进展,简单介绍了MEMS微陀螺仪的市场应用.微陀螺仪是MEMS器件中非常重要的一类器件.它的运用已经从单纯的航空领域逐渐转向汽车、消费电子行业等低端市场,这意味着微陀螺仪除了传统意义上的高精度高稳定性的要求,也可以向低精度商品化发展.传统的振动式陀螺,由于原理的局限性和加工技术的限制,很难达到战术级和惯性级的要求.导航级集成微陀螺(NGIMG)项目建议使用其他途径,以减少器件的可移动部件和降低工艺难度,从而提高其精度和抗干扰能力.各种设计方法近年来层出不穷,其中悬浮转子式微陀螺是目前精度最高的陀螺仪,微集成光学式陀螺也将在未来一段时间拥有巨大的研究潜力和发展空间.%The research progress of MEMS micro-gyroscopes are reviewed. The market applications of MEMS micro-gyroscopes are introduced briefly. Micro gyroscopes play a significant role in the MEMS devices. From aviation fields, its application has gradually shifted to the low-end market, such as automobile and consumer electronics, which means that instead of the high precision and stability, commercialization is another development direction. As the limitation of the principle and the fabrication technology, the traditional vibrating gyroscopes can hardly reach the tactical grade and the inertial grade. The NGIMG program, supported by DARPA, suggests to use other methods to reduce flexible components, decrease the processing difficulty and improve the precision and antijamming capability. In the recent years, endless varieties of designs are proposed. The micro levitated rotational gyroscope is the most precise gyroscope in the world now, and the MEOMS gyroscope also has a great research potential and development in the future.
田晓春; 李杰; 范玉宝; 陈伟; 刘俊
2012-01-01
针对传统MEMS陀螺仪输出信息为模拟量且易受干扰、噪声较大的问题,结合SAR150陀螺仪可以直接输出数字信号的特点,提出了一种新型的数字陀螺仪实时数据采集系统；该系统以FPGA为主控制器,通过SPI接口完成对MEMS陀螺仪SAR150的控制与数据的传输,实现了对陀螺仪输出信号的采集、实时传输及存储；通过将所研制的数据采集系统应用于SAR150陀螺仪测量角速率实验,并对测得数据进行误差分析,实验结果表明:数据采集系统采集输出的角速率值与理论值的绝对误差标准差均小于0.2°/s；且该系统的可靠性高、实时性好,为后续的陀螺仪测试及标定奠定了基础,有一定的工程应用价值.%According to the problem of traditional MEMS gyroscope output information for analog quantities and easy interference and larger noise, combining the characteristic of SAR150 gyroscope with digital signal, this paper introduces a new kind of real —time data acquisition system for digital gyroscope. The system which using FPGA as the main controller finished controlling the MEMS gyroscope SAR150 and data transmission through SPI interface, realizing the function of collection, real — time transmission and storage for the output information of gyroscope. By applying the data acquisition for angular rate measurement experiment and analyzing the measurement data error, the experimental results show that the absolute error standard deviation of the actual value and theoretical value is less than 0. 2°/s, at the same time, the reliability and real —time of the system was verified, which lay a foundation for the follow—up of the gyroscope test and calibration, and have certain engineering application value.
Research on MEMS gyroscope signal denoising based compressed sensing theory%基于压缩感知理论的MEMS陀螺仪信号降噪研究
程承; 潘泉; 王申龙; 程咏梅
2012-01-01
Through analyzing the limitation of wavelet threshold filter, this paper applies wavelet filter based on compressed sensing to reduce the signal noise of low accuracy (micro electro mechanical system,MEMS) gyroscope, and compares the two methods through experiments. The experiment result shows that the wavelet filter based on compressed sensing can effectively reduce the signal noise of MEMS gyroscope; and the denoising effect of the method is better than that of wavelet filter while its compression rate is comparatively large. The method can improve the bias stability of low accuracy MEMS gyroscope, and provide a new approach for reducing the signal noise of low accuracy MEMS gyroscope in practice.%通过分析传统小波阈值滤波的局限性,将基于压缩感知的小波滤波方法应用于低精度MEMS( micro electro mechanical system)陀螺仪信号降噪中,并与小波阈值滤波方法进行了实验对比,实验结果表明:基于压缩感知的小波滤波方法可以有效地去除MEMS陀螺仪输出信号中的噪声,并且在压缩比较大时基于压缩感知的滤波方法去噪效果优于小波阈值滤波方法,改善了低精度MEMS陀螺仪零偏稳定性,为工程中解决低精度MEMS陀螺仪降噪问题提供了新思路.
Effect of axial force on the performance of micromachined vibratory rate gyroscopes.
Hou, Zhanqiang; Xiao, Dingbang; Wu, Xuezhong; Dong, Peitao; Chen, Zhihua; Niu, Zhengyi; Zhang, Xu
2011-01-01
It is reported in the published literature that the resonant frequency of a silicon micromachined gyroscope decreases linearly with increasing temperature. However, when the axial force is considerable, the resonant frequency might increase as the temperature increases. The axial force is mainly induced by thermal stress due to the mismatch between the thermal expansion coefficients of the structure and substrate. In this paper, two types of micromachined suspended vibratory gyroscopes with slanted beams were proposed to evaluate the effect of the axial force. One type was suspended with a clamped-free (C-F) beam and the other one was suspended with a clamped-clamped (C-C) beam. Their drive modes are the bending of the slanted beam, and their sense modes are the torsion of the slanted beam. The relationships between the resonant frequencies of the two types were developed. The prototypes were packaged by vacuum under 0.1 mbar and an analytical solution for the axial force effect on the resonant frequency was obtained. The temperature dependent performances of the operated mode responses of the micromachined gyroscopes were measured. The experimental values of the temperature coefficients of resonant frequencies (TCF) due to axial force were 101.5 ppm/°C for the drive mode and 21.6 ppm/°C for the sense mode. The axial force has a great influence on the modal frequency of the micromachined gyroscopes suspended with a C-C beam, especially for the flexure mode. The quality factors of the operated modes decreased with increasing temperature, and changed drastically when the micromachined gyroscopes worked at higher temperatures.
Effect of Axial Force on the Performance of Micromachined Vibratory Rate Gyroscopes
Zhengyi Niu
2010-12-01
Full Text Available It is reported in the published literature that the resonant frequency of a silicon micromachined gyroscope decreases linearly with increasing temperature. However, when the axial force is considerable, the resonant frequency might increase as the temperature increases. The axial force is mainly induced by thermal stress due to the mismatch between the thermal expansion coefficients of the structure and substrate. In this paper, two types of micromachined suspended vibratory gyroscopes with slanted beams were proposed to evaluate the effect of the axial force. One type was suspended with a clamped-free (C-F beam and the other one was suspended with a clamped-clamped (C-C beam. Their drive modes are the bending of the slanted beam, and their sense modes are the torsion of the slanted beam. The relationships between the resonant frequencies of the two types were developed. The prototypes were packaged by vacuum under 0.1 mbar and an analytical solution for the axial force effect on the resonant frequency was obtained. The temperature dependent performances of the operated mode responses of the micromachined gyroscopes were measured. The experimental values of the temperature coefficients of resonant frequencies (TCF due to axial force were 101.5 ppm/°C for the drive mode and 21.6 ppm/°C for the sense mode. The axial force has a great influence on the modal frequency of the micromachined gyroscopes suspended with a C-C beam, especially for the flexure mode. The quality factors of the operated modes decreased with increasing temperature, and changed drastically when the micromachined gyroscopes worked at higher temperatures.
Avants, Brian B; Hackman, Daniel A; Betancourt, Laura M; Lawson, Gwendolyn M; Hurt, Hallam; Farah, Martha J
2015-01-01
What are the long-term effects of childhood experience on brain development? Research with animals shows that the quality of environmental stimulation and parental nurturance both play important roles in shaping lifelong brain structure and function. Human research has so far been limited to the effects of abnormal experience and pathological development. Using a unique longitudinal dataset of in-home measures of childhood experience at ages 4 and 8 and MRI acquired in late adolescence, we were able to relate normal variation in childhood experience to later life cortical thickness. Environmental stimulation at age 4 predicted cortical thickness in a set of automatically derived regions in temporal and prefrontal cortex. In contrast, age 8 experience was not predictive. Parental nurturance was not predictive at either age. This work reveals an association between childhood experience and later brain structure that is specific relative to aspects of experience, regions of brain, and timing.
van Dongen, Jeroen
2015-01-01
The Einstein-Rupp experiments have been unduly neglected in the history of quantum mechanics. While this is to be explained by the fact that Emil Rupp was later exposed as a fraud and had fabricated the results, it is not justified, due to the importance attached to the experiments at the time. This paper discusses Rupp's fraud, the relation between Albert Einstein and Rupp, and the Einstein-Rupp experiments, and argues that these experiments were an influence on Niels Bohr's development of complementarity and Werner Heisenberg's formulation of the uncertainty relations.
2016-01-01
Language acquisition is based on our knowledge about the world and forms through multiple sensory-motor interactions with the environment. We link the properties of individual experience formed at different stages of ontogeny with the phased development of sensory modalities and with the acquisition of words describing the appropriate forms of sensitivity. To test whether early-formed experience related to skin sensations, olfaction and taste differs from later-formed experience related to vision and hearing, we asked Russian-speaking participants to categorize or to assess the pleasantness of experience mentally reactivated by sense-related adjectives found in common dictionaries. It was found that categorizing adjectives in relation to vision, hearing and skin sensations took longer than categorizing adjectives in relation to olfaction and taste. In addition, experience described by adjectives predominantly related to vision, hearing and skin sensations took more time for the pleasantness judgment and generated less intense emotions than that described by adjectives predominantly related to olfaction and taste. Interestingly the dynamics of skin resistance corresponded to the intensity and pleasantness of reported emotions. We also found that sense-related experience described by early-acquired adjectives took less time for the pleasantness judgment and generated more intense and more positive emotions than that described by later-acquired adjectives. Correlations were found between the time of the pleasantness judgment of experience, intensity and pleasantness of reported emotions, age of acquisition, frequency, imageability and length of sense-related adjectives. All in all these findings support the hypothesis that early-formed experience is less differentiated than later-formed experience. PMID:27400090
Teachers' Literacy-Related Knowledge and Self-Perceptions in Relation to Preparation and Experience
Spear-Swerling, Louise; Brucker, Pamela Owen; Alfano, Michael P.
2005-01-01
After rating their own literacy-related knowledge in three areas (knowledge about reading/reading development, phonemic awareness/phonics, and morpheme awareness/structural analysis), graduate teacher-education students completed five tasks intended to measure their actual disciplinary knowledge in these areas. Teachers with high levels of prior…
Action Video Game Experience Related to Altered Large-Scale White Matter Networks.
Gong, Diankun; Ma, Weiyi; Gong, Jinnan; He, Hui; Dong, Li; Zhang, Dan; Li, Jianfu; Luo, Cheng; Yao, Dezhong
2017-01-01
With action video games (AVGs) becoming increasingly popular worldwide, the cognitive benefits of AVG experience have attracted continuous research attention over the past two decades. Research has repeatedly shown that AVG experience can causally enhance cognitive ability and is related to neural plasticity in gray matter and functional networks in the brain. However, the relation between AVG experience and the plasticity of white matter (WM) network still remains unclear. WM network modulates the distribution of action potentials, coordinating the communication between brain regions and acting as the framework of neural networks. And various types of cognitive deficits are usually accompanied by impairments of WM networks. Thus, understanding this relation is essential in assessing the influence of AVG experience on neural plasticity and using AVG experience as an interventional tool for impairments of WM networks. Using graph theory, this study analyzed WM networks in AVG experts and amateurs. Results showed that AVG experience is related to altered WM networks in prefrontal networks, limbic system, and sensorimotor networks, which are related to cognitive control and sensorimotor functions. These results shed new light on the influence of AVG experience on the plasticity of WM networks and suggested the clinical applicability of AVG experience.
Action Video Game Experience Related to Altered Large-Scale White Matter Networks
Diankun Gong
2017-01-01
Full Text Available With action video games (AVGs becoming increasingly popular worldwide, the cognitive benefits of AVG experience have attracted continuous research attention over the past two decades. Research has repeatedly shown that AVG experience can causally enhance cognitive ability and is related to neural plasticity in gray matter and functional networks in the brain. However, the relation between AVG experience and the plasticity of white matter (WM network still remains unclear. WM network modulates the distribution of action potentials, coordinating the communication between brain regions and acting as the framework of neural networks. And various types of cognitive deficits are usually accompanied by impairments of WM networks. Thus, understanding this relation is essential in assessing the influence of AVG experience on neural plasticity and using AVG experience as an interventional tool for impairments of WM networks. Using graph theory, this study analyzed WM networks in AVG experts and amateurs. Results showed that AVG experience is related to altered WM networks in prefrontal networks, limbic system, and sensorimotor networks, which are related to cognitive control and sensorimotor functions. These results shed new light on the influence of AVG experience on the plasticity of WM networks and suggested the clinical applicability of AVG experience.
Conover, David R.
2014-09-11
The purpose of this document is to identify laws, rules, model codes, codes, standards, regulations, specifications (CSR) related to safety that could apply to stationary energy storage systems (ESS) and experiences to date securing approval of ESS in relation to CSR. This information is intended to assist in securing approval of ESS under current CSR and to identification of new CRS or revisions to existing CRS and necessary supporting research and documentation that can foster the deployment of safe ESS.
Hendriks, A.; Janssen, G.T.L.; Kaarsemaker, M.; Mey, H.R.A. De
2013-01-01
Objective: One of the abilities involved in social cognition is perspective taking. According to Relational Frame Theory (RFT), perspective taking skills are based on the derivation of relations of perspective, and are learned and practiced in social interactions. Pronounced deficits in the
Keymeulen, Didier; Ferguson, Michael I.; Fink, Wolfgang; Oks, Boris; Peay, Chris; Terrile, Richard; Cheng, Yen; Kim, Dennis; MacDonald, Eric; Foor, David
2005-01-01
We propose a tuning method for MEMS gyroscopes based on evolutionary computation to efficiently increase the sensitivity of MEMS gyroscopes through tuning. The tuning method was tested for the second generation JPL/Boeing Post-resonator MEMS gyroscope using the measurement of the frequency response of the MEMS device in open-loop operation. We also report on the development of a hardware platform for integrated tuning and closed loop operation of MEMS gyroscopes. The control of this device is implemented through a digital design on a Field Programmable Gate Array (FPGA). The hardware platform easily transitions to an embedded solution that allows for the miniaturization of the system to a single chip.
Professionals’ Experiences of the Relations between Personal History and Professional Role
Hege Sjølie
2013-01-01
Full Text Available The purpose of this paper is to explore whether and how workers in a crisis resolution home treatment (CRHT team experience the relationship between their personal history and professional role. This paper is based on 13 in-depth interviews with health professionals working in CRHT. The interviews were analysed using a hermeneutic-phenomenological approach. Participants expressed that there is a relationship between their personal history and professional role, and three themes are highlighted as particularly important in, namely experiences related to the participants as individuals, work-related experiences and family-related experiences. The participants write meaning into the relationship between their personal history and professional role. By relating and exploring their own life stories in the interviews, they work on forming meaning and identity.
Event-by-event simulation of single-neutron experiments to test uncertainty relations
De Raedt, H.; Michielsen, K.
2014-01-01
Results from a discrete-event simulation of a recent single-neutron experiment that tests Ozawa's generalization of Heisenberg's uncertainty relation are presented. The event-based simulation algorithm reproduces the results of the quantum theoretical description of the experiment but does not requi
The Doppler effect and the three most famous experiments for special relativity
Klinaku, Shukri
Using the general formula for the Doppler effect at any arbitrary angle, the three famous experiments for special theory of relativity will be examined. Explanation of the experiments of Michelson, Kennedy-Thorndike and Ives-Stilwell will be given in a precise and elegant way without postulates, arbitrary assumptions or approximations.
Valiente, Carlos; Eisenberg, Nancy; Shepard, Stephanie A.; Fabes, Richard A.; Cumberland, Amanda J.; Losoya, Sandra H.; Spinrad, Tracy L.
2004-01-01
Guided by the heuristic model proposed by Eisenberg et al. [Psychol. Inq. 9 (1998) 241], we examined the relations of mothers' reported and observed negative expressivity to children's (N = 159; 74 girls; M age = 7.67 years) experience and expression of emotion. Children's experience and/or expression of emotion in response to a distressing film…
2015-01-01
In this paper, a gyroscopic mounting method for crystal oscillators to reduce the impact of dynamic loads on their output stability has been proposed. In order to prove the efficiency of this mounting approach, each dynamic load-induced instability has been analyzed in detail. A statistical study has been performed on the elevation angle of the g-sensitivity vector of Stress Compensated-cut (SC-cut) crystals. The analysis results show that the proposed gyroscopic mounting method gives good p...
Design and analysis of a dual-axis resonator fiber-optic gyroscope employing a single source.
Pinnoji, Prerana Dabral; Nayak, Jagannath
2013-08-01
In this paper, design of a resonator fiber-optic gyroscope comprised of a single laser source and two optical fiber resonator rings is presented. A typical gyroscope measures angular rotation around a fixed axis, whereas the proposed design can sense simultaneous rotation about two orthogonal axes. Two variants of the design are proposed and analyzed using a mathematical model based on Jones matrix methodology.
Brillouin/Raman compensation of the Kerr-effect-induced bias in a nonlinear ring laser gyroscope.
Luo, Zhang; Yuan, Xiaodong; Zhu, Zhihong; Liu, Ken; Ye, Weimin; Zeng, Chun; Ji, Jiarong
2013-04-01
In this Letter, the beat frequency at rest of a ring laser gyroscope with nonlinear effects is discussed in detail. Even without an additional intensity-stabilizing system, the random nullshift bias induced by the Kerr effect is compensated by the phase shift associated with the stimulated Brillouin/Raman scattering. And the nonlinear stimulated scattering also serves as the gain mechanism of the gyroscope. And thus the influence of the fluctuation of the injected pump intensity on the beat frequency is eliminated.
Petrović Ivana B.
2014-01-01
Full Text Available Workplace bullying has been identified as a widespread problem in contemporary organizational research. The aim of the paper was to acquire theoretically based and comparable findings about workplace bullying in Serbia: to explore the behavioral experience and self-labeling approaches (applying the Negative Acts Questionnaire - Revised, NAQ-R and their relationship with job-related behaviors. The sample comprised 1,998 employees. Prevalence rates of workplace bullying based on self-labeling and behavior experience approaches overlap significantly (70% of employees operationally identified as bullied had also labeled themselves as bullied. Both the self-labeling and behavioral experience approach showed significant correlations with job-related behaviors (perceived threat to a total job, absenteeism, intention to leave, and perceived productivity. Previously bullied, presently bullied and non-bullied employees differed significantly on all four job-related behaviors, with large effect size for the intention to leave and medium effect size for the perceived threat to a total job. The findings support combining self-labeling and behavioral experience approaches in workplace bullying research. [Projekat Ministarstva nauke Republike Srbije, br. 179018
Collin-Vezina, Delphine; Coleman, Kim; Milne, Lise; Sell, Jody; Daigneault, Isabelle
2011-01-01
The aim of this paper was to provide a description of the trauma experiences, trauma-related sequels, and resilience features of a sample of Canadian youth in residential care facilities, as well as to explore the impact of gender and of the number of different traumas experienced on trauma-related sequels and resilience features. A convenience…
Syed, Moin; Azmitia, Margarita
2010-01-01
The purpose in this longitudinal study was to investigate further the link between ethnic identity processes and content through an examination of emerging adults' narratives of ethnicity-related experiences. Seventy ethnically diverse college students completed an ethnic identity exploration index and told an ethnicity-related narrative on 2…
Psychometric Properties of Work-Related Behavior and Experience Patterns (AVEM) Scale
Gencer, R. Timucin; Boyacioglu, Hayal; Kiremitci, Olcay; Dogan, Birol
2010-01-01
"Work-Related Behaviour and Experience Patterns" (AVEM) has been developed with the intention of determining the occupation related behaviour and lifestyle models of professionals. This study has been conducted to test the validity and reliability of MEDYAM, the abbreviated Turkish equivalent of AVEM. 373 teachers from 10 different…