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Sample records for vibratory gyroscope principle

  1. Silicon Bulk Micromachined Vibratory Gyroscope

    Science.gov (United States)

    Tang, T. K.; Gutierrez, R. C.; Wilcox, J. Z.; Stell, C.; Vorperian, V.; Calvet, R.; Li, W. J.; Charkaborty, I.; Bartman, R.; Kaiser, W. J.

    1996-01-01

    This paper reports on design, modeling, fabrication, and characterization of a novel silicon bulk micromachined vibratory rate gyroscope designed for microspacecraft applications. The new microgyroscope consists of a silicon four leaf cloverstructure with a post attached to the center.

  2. A vibratory micromechanical gyroscope

    Science.gov (United States)

    Boxenhorn, Burton; Greiff, Paul

    A novel vibratory micromechanical gyro with an active area less than one millimeter square has been analyzed, designed, and built. It has been demonstrated that such a gyro can be built using semiconductor fabrication techniques, and that the resulting performance is reasonably predictable. Further improvement of this gyro will result in an instrument that is small, low power, and in particular, will be very cheap in large quantitites.

  3. GEC Ferranti piezo vibratory gyroscope

    Science.gov (United States)

    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.

  4. Parametrically disciplined operation of a vibratory gyroscope

    Science.gov (United States)

    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.

  5. Coriolis vibratory gyroscopes theory and design

    CERN Document Server

    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.

  6. Modification of piezoelectric vibratory gyroscope resonator parameters by feedback control

    CSIR Research Space (South Africa)

    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...

  7. Vibratory gyroscopes : identification of mathematical model from test data

    CSIR Research Space (South Africa)

    Shatalov, MY

    2007-05-01

    Full Text Available Simple mathematical model of vibratory gyroscopes imperfections is formulated, which includes anisotropic damping and variation of mass-stiffness parameters and their harmonics. The method of identification of parameters of the mathematical model...

  8. Adaptive Control of a Vibratory Angle Measuring Gyroscope

    Science.gov (United States)

    Park, Sungsu

    2010-01-01

    This paper presents an adaptive control algorithm for realizing a vibratory angle measuring gyroscope so that rotation angle can be directly measured without integration of angular rate, thus eliminating the accumulation of numerical integration errors. The proposed control algorithm uses a trajectory following approach and the reference trajectory is generated by an ideal angle measuring gyroscope driven by the estimate of angular rate and the auxiliary sinusoidal input so that the persistent excitation condition is satisfied. The developed control algorithm can compensate for all types of fabrication imperfections such as coupled damping and stiffness, and mismatched stiffness and un-equal damping term in an on-line fashion. The simulation results show the feasibility and effectiveness of the developed control algorithm that is capable of directly measuring rotation angle without the integration of angular rate. PMID:22163667

  9. General problems of dynamics and control of vibratory gyroscopes

    CSIR Research Space (South Africa)

    Shatalov, MY

    2008-05-01

    Full Text Available resonator gyroscope. The foundations of feedback control in the gyroscopes are considered and classification of the main operational regimes is given in terms of the integral manifolds and new classes of nonlinear parametric excitation forces are added...

  10. Compensation of Imperfections for Vibratory Gyroscope Systems Using State Observers

    Directory of Open Access Journals (Sweden)

    Chien-Yu CHI

    2009-08-01

    Full Text Available This paper presents a novel approach that can compensate errors resulting from the imperfections of mechanical structures and interface circuits for MEMS gyroscope systems. Different from most of existing researches on gyroscopes wherein the mechanical structure and interface circuit are either assumed to be ideal or optimized individually, this approach uses state estimation techniques to compensate all those errors and to obtain correct angular rates in real time. The mechanical structure errors discussed in this paper may come from structure designs and fabrication imperfections. The interface circuit errors include: mismatch of differential capacitors, parasitic capacitance, offset voltage of operation amplifiers, and circuit noise. Simulation results indicates that, with the presence of those errors and a signal-to-noise ratio around 20, the proposed method can measure time-varying angular rates with a bandwidth up to 30 Hz and a sensing accuracy of 1×10-2 rad/sec.

  11. Mechanical and Electrical Noise in Sense Channel of MEMS Vibratory Gyroscopes.

    Science.gov (United States)

    Ding, Xukai; Jia, Jia; Gao, Yang; Li, Hongsheng

    2017-10-11

    This paper presents a theoretical analysis of mechanical and electrical noise in the sense channel of micro-electromechanical systems (MEMS) vibratory gyroscopes. Closed-form expressions for the power spectral density (PSD) of the noise equivalent rate (NER) of gyroscopes in the open-loop and the force-rebalance operations are derived by using an averaged PSD model and an equivalent transfer function. The obtained expressions are verified through numerical simulations, demonstrating close agreements between the analytic and the numerical models. Based on the derived expressions for the PSD of the NER, the impacts of the modal frequency split, quality factor, and the gain of the feedback forcer, as well as the gain of the signal conditioning circuit, on the gyroscope noise characteristics are theoretically analyzed. In addition, the angle random walk (ARW) and the standard deviation of the NER are also discussed through the PSD models. Finally, the effects of the loop closing, the mode matching, and the gain of the feedback forcer on the PSD of the NER were verified via a MEMS vibratory gyroscope with a tunable modal frequency split.

  12. System Modeling of a MEMS Vibratory Gyroscope and Integration to Circuit Simulation.

    Science.gov (United States)

    Kwon, Hyukjin J; Seok, Seyeong; Lim, Geunbae

    2017-11-18

    Recently, consumer applications have dramatically created the demand for low-cost and compact gyroscopes. Therefore, on the basis of microelectromechanical systems (MEMS) technology, many gyroscopes have been developed and successfully commercialized. A MEMS gyroscope consists of a MEMS device and an electrical circuit for self-oscillation and angular-rate detection. Since the MEMS device and circuit are interactively related, the entire system should be analyzed together to design or test the gyroscope. In this study, a MEMS vibratory gyroscope is analyzed based on the system dynamic modeling; thus, it can be mathematically expressed and integrated into a circuit simulator. A behavioral simulation of the entire system was conducted to prove the self-oscillation and angular-rate detection and to determine the circuit parameters to be optimized. From the simulation, the operating characteristic according to the vacuum pressure and scale factor was obtained, which indicated similar trends compared with those of the experimental results. The simulation method presented in this paper can be generalized to a wide range of MEMS devices.

  13. System Modeling of a MEMS Vibratory Gyroscope and Integration to Circuit Simulation

    Directory of Open Access Journals (Sweden)

    Hyukjin J. Kwon

    2017-11-01

    Full Text Available Recently, consumer applications have dramatically created the demand for low-cost and compact gyroscopes. Therefore, on the basis of microelectromechanical systems (MEMS technology, many gyroscopes have been developed and successfully commercialized. A MEMS gyroscope consists of a MEMS device and an electrical circuit for self-oscillation and angular-rate detection. Since the MEMS device and circuit are interactively related, the entire system should be analyzed together to design or test the gyroscope. In this study, a MEMS vibratory gyroscope is analyzed based on the system dynamic modeling; thus, it can be mathematically expressed and integrated into a circuit simulator. A behavioral simulation of the entire system was conducted to prove the self-oscillation and angular-rate detection and to determine the circuit parameters to be optimized. From the simulation, the operating characteristic according to the vacuum pressure and scale factor was obtained, which indicated similar trends compared with those of the experimental results. The simulation method presented in this paper can be generalized to a wide range of MEMS devices.

  14. Structural-Acoustic Coupling Effects on the Non-Vacuum Packaging Vibratory Cylinder Gyroscope

    Science.gov (United States)

    Xi, Xiang; Wu, Xuezhong; Wu, Yulie; Zhang, Yongmeng; Tao, Yi; Zheng, Yu; Xiao, Dingbang

    2013-01-01

    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. PMID:24351631

  15. Effect of Axial Force on the Performance of Micromachined Vibratory Rate Gyroscopes

    Directory of Open Access Journals (Sweden)

    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.

  16. Effect of axial force on the performance of micromachined vibratory rate gyroscopes.

    Science.gov (United States)

    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.

  17. A novel oscillation control for MEMS vibratory gyroscopes using a modified electromechanical amplitude modulation technique

    Science.gov (United States)

    Ma, Wei; Lin, Yiyu; Liu, Siqi; Zheng, Xudong; Jin, Zhonghe

    2017-02-01

    This paper reports a novel oscillation control algorithm for MEMS vibratory gyroscopes using a modified electromechanical amplitude modulation (MEAM) technique, which enhances the robustness against the frequency variation of the driving mode, compared to the conventional EAM (CEAM) scheme. In this approach, the carrier voltage exerted on the proof mass is frequency-modulated by the drive resonant frequency. Accordingly, the pick-up signal from the interface circuit involves a constant-frequency component that contains the amplitude and phase information of the vibration displacement. In other words, this informational detection signal is independent of the mechanical resonant frequency, which varies due to different batches, imprecise micro-fabrication and changing environmental temperature. In this paper, the automatic gain control loop together with the phase-locked loop are simultaneously analyzed using the averaging method and Routh-Hurwitz criterion, deriving the stability condition and the parameter optimization rules of the transient response. Then, a simulation model based on the real system is set up to evaluate the control algorithm. Further, the proposed MEAM method is tested using a field-programmable-gate-array based digital platform on a capacitive vibratory gyroscope. By optimizing the control parameters, the transient response of the drive amplitude reveals a settling time of 45.2 ms without overshoot, according well with the theoretical prediction and simulation results. The first measurement results show that the amplitude variance of the drive displacement is 12 ppm in an hour while the phase standard deviation is as low as 0.0004°. The mode-split gyroscope operating under atmospheric pressure demonstrates an outstanding performance. By virtue of the proposed MEAM method, the bias instability and angle random walk are measured to be 0.9° h-1 (improved by 2.4 times compared to the CEAM method) and 0.068° (√h)-1 (improved by 1.4 times

  18. Effect of residual stress on modal patterns of MEMS vibratory gyroscope

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Shankar, E-mail: shankardutta77@gmail.com; Panchal, Abha; Kumar, Manoj; Pal, Ramjay; Bhan, R. K. [Solid State Physics Laboratory, DRDO, Lucknow Road, Timarpur, Delhi, India 110054 (India)

    2016-04-13

    Deep boron diffusion often induces residual stress in bulk micromachined MEMS structures, which may affect the MEMS devices operation. In this study, we studied the modal patterns of MEMS vibratory gyroscope under the residual stress (100 – 1000 MPa). Modal patterns and modal frequencies of the gyro are found to be dependent on the residual stress values. Without any residual stress, the modal frequencies drive and sense modeswere found to be 20.06 kHz and 20.36 kHz respectively. In presence of 450 MPa residual stress, the modal frequencies of the drive and sense modes were changed to 42.75 kHz and 43.07 kHz respectively.

  19. Two Novel Measurements for the Drive-Mode Resonant Frequency of a Micromachined Vibratory Gyroscope

    Directory of Open Access Journals (Sweden)

    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.

  20. Design and Analysis of a Novel Fully Decoupled Tri-axis Linear Vibratory Gyroscope with Matched Modes.

    Science.gov (United States)

    Xia, Dunzhu; Kong, Lun; Gao, Haiyu

    2015-07-13

    We present in this paper a novel fully decoupled silicon micromachined tri-axis linear vibratory gyroscope. The proposed gyroscope structure is highly symmetrical and can be limited to an area of about 8.5 mm × 8.5 mm. It can differentially detect three axes' angular velocities at the same time. By elaborately arranging different beams, anchors and sensing frames, the drive and sense modes are fully decoupled from each other. Moreover, the quadrature error correction and frequency tuning functions are taken into consideration in the structure design for all the sense modes. Since there exists an unwanted in-plane rotational mode, theoretical analysis is implemented to eliminate it. To accelerate the mode matching process, the particle swam optimization (PSO) algorithm is adopted and a frequency split of 149 Hz is first achieved by this method. Then, after two steps of manual adjustment of the springs' dimensions, the frequency gap is further decreased to 3 Hz. With the help of the finite element method (FEM) software ANSYS, the natural frequencies of drive, yaw, and pitch/roll modes are found to be 14,017 Hz, 14,018 Hz and 14,020 Hz, respectively. The cross-axis effect and scale factor of each mode are also simulated. All the simulation results are in good accordance with the theoretical analysis, which means the design is effective and worthy of further investigation on the integration of tri-axis accelerometers on the same single chip to form an inertial measurement unit.

  1. A Mode Matched Triaxial Vibratory Wheel Gyroscope with Fully Decoupled Structure.

    Science.gov (United States)

    Xia, Dunzhu; Kong, Lun; Gao, Haiyu

    2015-11-17

    To avoid the oscillation of four unequal masses seen in previous triaxial linear gyroscopes, a modified silicon triaxial gyroscope with a rotary wheel is presented in this paper. To maintain a large sensitivity and suppress the coupling of different modes, this novel gyroscope structure is designed be perfectly symmetrical with a relatively large size of about 9.8 mm × 9.8 mm. It is available for differentially detecting three-axis angular rates simultaneously. To overcome the coupling between drive and sense modes, numerous necessary frames, beams, and anchors are delicately figured out and properly arranged. Besides, some frequency tuning and feedback mechanisms are addressed in the case of post processing after fabrication. To facilitate mode matched function, a new artificial fish swarm algorithm (AFSA) performed faster than particle swarm optimization (PSO) with a frequency split of 108 Hz. Then, by entrusting the post adjustment of the springs dimensions to the finite element method (FEM) software ANSYS, the final frequency splits can be below 3 Hz. The simulation results demonstrate that the modal frequencies in drive and different sense modes are respectively 8001.1, 8002.6, 8002.8 and 8003.3 Hz. Subsequently, different axis cross coupling effects and scale factors are also analyzed. The simulation results effectively validate the feasibility of the design and relevant theoretical calculation.

  2. Novel optical gyroscope: proof of principle demonstration and future scope.

    Science.gov (United States)

    Srivastava, Shailesh; Rao D S, Shreesha; Nandakumar, Hari

    2016-10-03

    We report the first proof-of-principle demonstration of the resonant optical gyroscope with reflector that we have recently proposed. The device is very different from traditional optical gyroscopes since it uses the inherent coupling between the clockwise and counterclockwise propagating waves to sense the rotation. Our demonstration confirms our theoretical analysis and simulations. We also demonstrate a novel method of biasing the gyroscope using orthogonal polarization states. The simplicity of the structure and the readout method, the theoretically predicted high sensitivities (better than 0.001 deg/hr), and the possibility of further performance enhancement using a related laser based active device, all have immense potential for attracting fresh research and technological initiatives.

  3. Gyroscope precession in special and general relativity from basic principles

    Science.gov (United States)

    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.

  4. Design of a Novel MEMS Gyroscope Array

    OpenAIRE

    Wang, Wei; Lv, Xiaoyong; Sun, Feng

    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 ...

  5. Design of a novel MEMS gyroscope array.

    Science.gov (United States)

    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.

  6. The development of micromachined gyroscope structure and circuitry technology.

    Science.gov (United States)

    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.

  7. The Development of Micromachined Gyroscope Structure and Circuitry Technology

    Directory of Open Access Journals (Sweden)

    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.

  8. Research on Bell-Shaped Vibratory Angular Rate Gyro’s Character of Resonator

    Directory of Open Access Journals (Sweden)

    Hong Liu

    2013-04-01

    Full Text Available Bell-shaped vibratory angular rate gyro (abbreviated as BVG is a new type Coriolis vibratory gyro that was inspired by Chinese traditional clocks. The resonator fuses based on a variable thickness axisymmetric multicurved surface shell. Its characteristics can directly influence the performance of BVG. The BVG structure not only has capabilities of bearing high overload, high impact and, compared with the tuning fork, vibrating beam, shell and a comb structure, but also a higher frequency to overcome the influence of the disturbance of the exterior environment than the same sized hemispherical resonator gyroscope (HRG and the traditional cylinder vibratory gyroscope. It can be widely applied in high dynamic low precision angular rate measurement occasions. The main work is as follows: the issue mainly analyzes the structure and basic principle, and investigates the bell-shaped resonator’s mathematical model. The reasonable structural parameters are obtained from finite element analysis and an intelligent platform. Using the current solid vibration gyro theory analyzes the structural characteristics and principles of BVG. The bell-shaped resonator is simplified as a paraboloid of the revolution mechanical model, which has a fixed closed end and a free opened end. It obtains the natural frequency and vibration modes based on the theory of elasticity. The structural parameters are obtained from the orthogonal method by the research on the structural parameters of the resonator analysis. It obtains the modal analysis, stress analysis and impact analysis with the chosen parameters. Finally, using the turntable experiment verifies the gyro effect of the BVG.

  9. Split-resonator integrated-post MEMS gyroscope

    Science.gov (United States)

    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.

  10. Genetics Home Reference: vibratory urticaria

    Science.gov (United States)

    ... Facebook Twitter Home Health Conditions vibratory urticaria vibratory urticaria Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Vibratory urticaria is a condition in which exposing the skin ...

  11. Error Model and Compensation of Bell-Shaped Vibratory Gyro

    OpenAIRE

    Zhong Su; Ning Liu; Qing Li

    2015-01-01

    A bell-shaped vibratory angular velocity gyro (BVG), inspired by the Chinese traditional bell, is a type of axisymmetric shell resonator gyroscope. This paper focuses on development of an error model and compensation of the BVG. A dynamic equation is firstly established, based on a study of the BVG working mechanism. This equation is then used to evaluate the relationship between the angular rate output signal and bell-shaped resonator character, analyze the influence of the main error source...

  12. Microelectromechanical gyroscope

    Science.gov (United States)

    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.

  13. Coupled electromechanical model of an imperfect piezoelectric vibrating cylinder gyroscope

    CSIR Research Space (South Africa)

    Loveday, PW

    1996-01-01

    Full Text Available Coupled electromechanical equations of motion, describing the dynamics of a vibrating cylinder gyroscope, are derived using Hamilton's principle and the Rayleigh-Ritz method. The vibrating cylinder gyroscope comprises a thin walled steel cylinder...

  14. Characterization of the Bell-Shaped Vibratory Angular Rate Gyro

    Directory of Open Access Journals (Sweden)

    Junfang Fan

    2013-08-01

    Full Text Available The bell-shaped vibratory angular rate gyro (abbreviated as BVG is a novel shell vibratory gyroscope, which is inspired by the Chinese traditional bell. It sensitizes angular velocity through the standing wave precession effect. The bell-shaped resonator is a core component of the BVG and looks like the millimeter-grade Chinese traditional bell, such as QianLong Bell and Yongle Bell. It is made of Ni43CrTi, which is a constant modulus alloy. The exciting element, control element and detection element are uniformly distributed and attached to the resonator, respectively. This work presents the design, analysis and experimentation on the BVG. It is most important to analyze the vibratory character of the bell-shaped resonator. The strain equation, internal force and the resonator's equilibrium differential equation are derived in the orthogonal curvilinear coordinate system. When the input angular velocity is existent on the sensitive axis, an analysis of the vibratory character is performed using the theory of thin shells. On this basis, the mode shape function and the simplified second order normal vibration mode dynamical equation are obtained. The coriolis coupling relationship about the primary mode and secondary mode is established. The methods of the signal processing and control loop are presented. Analyzing the impact resistance property of the bell-shaped resonator, which is compared with other shell resonators using the Finite Element Method, demonstrates that BVG has the advantage of a better impact resistance property. A reasonable means of installation and a prototypal gyro are designed. The gyroscopic effect of the BVG is characterized through experiments. Experimental results show that the BVG has not only the advantages of low cost, low power, long work life, high sensitivity, and so on, but, also, of a simple structure and a better impact resistance property for low and medium angular velocity measurements.

  15. Dynamics and control of vibratory gyroscopes with special spherical symmetry

    CSIR Research Space (South Africa)

    Shatalov, M

    2006-01-01

    Full Text Available are obtained in the spherical Bessel and the associated Legendre functions, the effects of rotation are investigated and scales factors are determined for different vibrating modes of the spherical body, spheroidal and torsional. Corresponding scales factors...

  16. Quantum Spin Gyroscope

    Science.gov (United States)

    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...Abstract Gyroscopes find wide application in everyday life, from navigation to rotation sensors in hand-held devices and automobiles. In addition, they can

  17. Design, Modelling and Fabrication of a 40-330 Hz Dual-Mass MEMS Gyroscope on Thick-SOI Technology

    NARCIS (Netherlands)

    Rajaraman, V.; Sabageh, I.; French, P.; Pansraud, G.; Cretu, E.

    2011-01-01

    This work reports the design, modelling, fabrication and preliminary functionality testing of a dual-mass MEMS vibratory gyroscope for application in medical instrumentation, among others. The two-framed gyro has drive and sense mode resonance frequencies of 2500Hz and 2830Hz, with its bandwidth

  18. MEMS Gyroscopes Based on Acoustic Sagnac Effect

    Directory of Open Access Journals (Sweden)

    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.

  19. Design of a LC-tuned magnetically suspended rotating gyroscope

    Science.gov (United States)

    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.

  20. Dynamic Characteristics of Vertically Coupled Structures and the Design of a Decoupled Micro Gyroscope

    Science.gov (United States)

    Choi, Bumkyoo; Lee, Seung-Yop; Kim, Taekhyun; Baek, Seog Soon

    2008-01-01

    In a vertical type, vibratory gyroscope, the coupled motion between reference (driving) and sensing vibrations causes the zero-point output, which is the unwanted sensing vibration without angular velocity. This structural coupling leads to an inherent discrepancy between the natural frequencies of the reference and the sensing oscillations, causing curve veering in frequency loci. The coupled motion deteriorates sensing performance and dynamic stability. In this paper, the dynamic characteristics associated with the coupling phenomenon are theoretically analyzed. The effects of reference frequency and coupling factor on the rotational direction and amplitude of elliptic oscillation are determined. Based on the analytical studies on the coupling effects, we propose and fabricate a vertically decoupled vibratory gyroscope with the frequency matching. PMID:27879903

  1. Fiberless Optical Gyroscope Project

    Data.gov (United States)

    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...

  2. Fiberless Optical Gyroscope Project

    Data.gov (United States)

    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...

  3. Error Model and Compensation of Bell-Shaped Vibratory Gyro.

    Science.gov (United States)

    Su, Zhong; Liu, Ning; Li, Qing

    2015-09-17

    A bell-shaped vibratory angular velocity gyro (BVG), inspired by the Chinese traditional bell, is a type of axisymmetric shell resonator gyroscope. This paper focuses on development of an error model and compensation of the BVG. A dynamic equation is firstly established, based on a study of the BVG working mechanism. This equation is then used to evaluate the relationship between the angular rate output signal and bell-shaped resonator character, analyze the influence of the main error sources and set up an error model for the BVG. The error sources are classified from the error propagation characteristics, and the compensation method is presented based on the error model. Finally, using the error model and compensation method, the BVG is calibrated experimentally including rough compensation, temperature and bias compensation, scale factor compensation and noise filter. The experimentally obtained bias instability is from 20.5°/h to 4.7°/h, the random walk is from 2.8°/h(1/2) to 0.7°/h(1/2) and the nonlinearity is from 0.2% to 0.03%. Based on the error compensation, it is shown that there is a good linear relationship between the sensing signal and the angular velocity, suggesting that the BVG is a good candidate for the field of low and medium rotational speed measurement.

  4. Topological Gyroscopic Metamaterials

    Science.gov (United States)

    Nash, Lisa Michelle

    Topological materials are generally insulating in their bulk, with protected conducting states on their boundaries that are robust against disorder and perturbation of material property. The existence of these conducting edge states is characterized by an integer topological invariant. Though the phenomenon was first discovered in electronic systems, recent years have shown that topological states exist in classical systems as well. In this thesis we are primarily concerned with the topological properties of gyroscopic materials, which are created by coupling networks of fast-spinning objects. Through a series of simulations, numerical calculations, and experiments, we show that these materials can support topological edge states. We find that edge states in these gyroscopic metamaterials bear the hallmarks of topology related to broken time reversal symmetry: they transmit excitations unidirectionally and are extremely robust against experimental disorder. We also explore requirements for topology by studying several lattice configurations and find that topology emerges naturally in gyroscopic systems.A simple prescription can be used to create many gyroscopic lattices. Though many of our gyroscopic networks are periodic, we explore amorphous point-sets and find that topology also emerges in these networks.

  5. Electrostatically controlled micromechanical gyroscope

    Science.gov (United States)

    Hawkey, Timothy (Inventor); Torti, Richard (Inventor); Johnson, Bruce (Inventor)

    1994-01-01

    An integrated electrostatically-controlled micromechanical gyroscope with a rotor encompassed within a rotor cavity and electrostatically spun within the cavity. The gyroscope includes a plurality of axial electrostatic rotor actuators above and below the rotor for controlling the axial and tilt position of the rotor within the cavity, and a plurality of radial electrostatic actuators spaced circumferentially around the rotor for controlling the radial and tilt position of the rotor within the cavity. The position of the rotor within the cavity is then resolved to determine the external forces acting on the rotor.

  6. Instability of Gyroscopic Systems

    DEFF Research Database (Denmark)

    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...

  7. Stability analysis of the Gyroscopic Power Take-Off wave energy point absorber

    DEFF Research Database (Denmark)

    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...

  8. Gyroscope Technology and Applications: A Review in the Industrial Perspective.

    Science.gov (United States)

    Passaro, Vittorio M N; Cuccovillo, Antonello; Vaiani, Lorenzo; Carlo, Martino De; Campanella, Carlo Edoardo

    2017-10-07

    This paper is an overview of current gyroscopes and their roles based on their applications. The considered gyroscopes include mechanical gyroscopes and optical gyroscopes at macro- and micro-scale. Particularly, gyroscope technologies commercially available, such as Mechanical Gyroscopes, silicon MEMS Gyroscopes, Ring Laser Gyroscopes (RLGs) and Fiber-Optic Gyroscopes (FOGs), are discussed. The main features of these gyroscopes and their technologies are linked to their performance.

  9. Disc resonator gyroscope fabrication process requiring no bonding alignment

    Science.gov (United States)

    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.

  10. Advances in Gyroscope Technologies

    CERN Document Server

    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

  11. On dynamics and control of vibratory gyroscopes with special spherical symmetry

    CSIR Research Space (South Africa)

    Shatalov, M

    2006-05-01

    Full Text Available are obtained in the spherical Bessel and the associated Legendre functions, the effects of rotation are investigated and scales factors are determined for different vibrating modes of the spherical body, spheroidal and torsional. Corresponding scales factors...

  12. Fast Light Optical Gyroscopes

    Science.gov (United States)

    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.

  13. Self powered Autonomous Underwater Vehicles (AUVs): Results from a gyroscopic energy scavenging prototype

    OpenAIRE

    TOWNSEND, NICHOLAS

    2016-01-01

    This paper describes and presents preliminary experimental results from a novel prototype energy scavenging system installed in a model 2m cylindrical Autonomous Underwater Vehicle (AUV). The system, which is based on control moment gyroscope (CMG) principles, utilises the gyroscopic response of a gimballed flywheel mounted within an AUV body to generate energy from the wave induced rotational motions of the vehicle. This method, of using the reaction of a spinning wheel under an input torque...

  14. Configuration System for Simulation Based Design of Vibratory Bowl Feeders

    DEFF Research Database (Denmark)

    Hansson, Michael Natapon; Mathiesen, Simon; Ellekilde, Lars-Peter

    2017-01-01

    Vibratory bowl feeders are still among the most commonly used production equipment for automated part feeding, where parts are correctly oriented for further manipulation by being conveyed through a set of orienting devices. Designing vibratory bowl feeders involves selecting and sequencing a num...... the configuration task. To test the approach, the configuration system is used to find three device sequences for feeding three parts in specific orientations. The sequences are validated through simulation and real world experiments, showing good consistency....

  15. High performance MEMS micro-gyroscope

    Science.gov (United States)

    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.

  16. Optimization of vibratory welding process parameters using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Pravin Kumar; Kumar, S. Deepak; Patel, D.; Prasad, S. B. [National Institute of Technology Jamshedpur, Jharkhand (India)

    2017-05-15

    The current investigation was carried out to study the effect of vibratory welding technique on mechanical properties of 6 mm thick butt welded mild steel plates. A new concept of vibratory welding technique has been designed and developed which is capable to transfer vibrations, having resonance frequency of 300 Hz, into the molten weld pool before it solidifies during the Shielded metal arc welding (SMAW) process. The important process parameters of vibratory welding technique namely welding current, welding speed and frequency of the vibrations induced in molten weld pool were optimized using Taguchi’s analysis and Response surface methodology (RSM). The effect of process parameters on tensile strength and hardness were evaluated using optimization techniques. Applying RSM, the effect of vibratory welding parameters on tensile strength and hardness were obtained through two separate regression equations. Results showed that, the most influencing factor for the desired tensile strength and hardness is frequency at its resonance value, i.e. 300 Hz. The micro-hardness and microstructures of the vibratory welded joints were studied in detail and compared with those of conventional SMAW joints. Comparatively, uniform and fine grain structure has been found in vibratory welded joints.

  17. Parameter estimation and interval type-2 fuzzy sliding mode control of a z-axis MEMS gyroscope.

    Science.gov (United States)

    Fazlyab, Mahyar; Pedram, Maysam Zamani; Salarieh, Hassan; Alasty, Aria

    2013-11-01

    This paper reports a hybrid intelligent controller for application in single axis MEMS vibratory gyroscopes. First, unknown parameters of a micro gyroscope including unknown time varying angular velocity are estimated online via normalized continuous time least mean squares algorithm. Then, an additional interval type-2 fuzzy sliding mode control is incorporated in order to match the resonant frequencies and to compensate for undesired mechanical couplings. The main advantage of this control strategy is its robustness to parameters uncertainty, external disturbance and measurement noise. Consistent estimation of parameters is guaranteed and stability of the closed-loop system is proved via the Lyapunov stability theorem. Finally, numerical simulation is done in order to validate the effectiveness of the proposed method, both for a constant and time-varying angular rate. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

  18. The Gravity Probe B Gyroscopes

    Science.gov (United States)

    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.

  19. Effects of ejaculation by penile vibratory stimulation on bladder capacity in men with spinal cord lesions

    DEFF Research Database (Denmark)

    Laessøe, Line; Sønksen, Jens; Bagi, Per

    2003-01-01

    We examined the effects of ejaculation by penile vibratory stimulation on bladder capacity in men with spinal cord lesions.......We examined the effects of ejaculation by penile vibratory stimulation on bladder capacity in men with spinal cord lesions....

  20. A Multi-Fork Z-Axis Quartz Micromachined Gyroscope

    Directory of Open Access Journals (Sweden)

    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.

  1. A Multi-Fork Z-Axis Quartz Micromachined Gyroscope

    Science.gov (United States)

    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. PMID:24048339

  2. Precise laser gyroscope for autonomous inertial navigation

    Energy Technology Data Exchange (ETDEWEB)

    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)

  3. Gravity Probe B Gyroscope Rotor

    Science.gov (United States)

    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.)

  4. Aerodynamic Drag and Gyroscopic Stability

    CERN Document Server

    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...

  5. A subharmonic vibratory pattern in normal vocal folds

    NARCIS (Netherlands)

    Svec, JG; Schutte, HK; Miller, DG

    This study observes in detail an F-0/2 (sounding an octave below an original tone) subharmonic vibratory pattern produced in a normal larynx. Simultaneous electroglottographic and photoglottographic measurements reveal two different open phases within a subharmonic cycle-the first shorter with a

  6. Automation Selection and Sequencing of Traps for Vibratory Feeders

    DEFF Research Database (Denmark)

    Mathiesen, Simon; Ellekilde, Lars-Peter

    2017-01-01

    Vibratory parts feeders with mechanical orienting devices are used extensively in the assembly automation industry. Even so, the design process is based on trial-and-error approaches and is largely manual. In this paper, a methodology is presented for automatic design of this type of feeder...

  7. Design and analysis of a novel virtual gyroscope with multi-gyroscope and accelerometer array.

    Science.gov (United States)

    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.

  8. A New Hybrid Gyroscope with Electrostatic Negative Stiffness Tuning

    Directory of Open Access Journals (Sweden)

    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.

  9. A new hybrid gyroscope with electrostatic negative stiffness tuning.

    Science.gov (United States)

    Yang, Bo; Guan, Yumei; Wang, Shourong; Zou, Qi; Chu, Xian; Xue, Haiyan

    2013-05-30

    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.

  10. A Precise Bound for Gyroscopic Stabilization

    DEFF Research Database (Denmark)

    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...

  11. Nonlinear fiber gyroscope for quantum metrology

    OpenAIRE

    Luis, Alfredo; Morales, Irene; 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.

  12. Gyroscopic Motion: Show Me the Forces!

    Science.gov (United States)

    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…

  13. Laterally self-oscillated and force-balanced microvibratory gyroscope packaged in a vacuum package with a conditioning ASIC

    Science.gov (United States)

    Park, Kyu-Yeon; Lee, Chong-Won; Oh, Yong-Soo; Lee, Byeungleul

    1997-11-01

    A novel concept self-oscillator and dynamically tunable micro vibratory gyroscope, where oscillating, position- sensing and force-balancing take place on the wafer surface, has been developed. The gyroscope consists of: a grid-type planar mass which oscillates on the wafer surface; pairs of the differential capacitor type with LT shape position sense electrodes; a pair of force-balancing electrodes; oppositely placed comb-drive and comb-sensor for mass self-oscillation; fish hook shape springs to match the first and second modes with the mass oscillating and position sensing modes, respectively. The natural frequency of the position sensing mode is lowered and tuned by the DC bias voltage applied to the position sense electrodes and then finely tuned by DC bias on a pair of force-balancing electrodes. To reduce the mass exciting along the sensing direction, we drive the mass by the same DC and opposite AC driving voltage on the oppositely placed comb-drives. It also features that the position sensing electric interference ins reduced. The mass is self-oscillated by the condition of limit cycle, so the mass is always oscillated in the natural frequency even if the natural frequency is varied by the environment and/or it has displacement-force nonlinear behavior. The gyroscope is fabricated on the silicon wafer by surface micromachining technology and the polysilicon is used as an active structure. The gyroscope has an active size of 700 by 600 micro meters, the thickness of the structure is 7 micron meters and the proof mass of 1 micro gram. To improve the resolution of the gyro, it is packaged in the 50 mili-torr vacuum package with a conditioning ASIC. Experimental results show that the gyroscope has the equivalent noise level of 0.1 deg/sec at 2 Hz, the bandwidth of 100 Hz, linearity of 1 percent FS and the sensing range of 90 deg/sec.

  14. Development of vibratory stress relief actuators based on giant magnetostrictive materials

    Science.gov (United States)

    He, Wen

    2005-12-01

    A kind of actuator, which is used in the high frequency Vibratory Stress Relief (VSR), was researched. The actuator is based on the technology of giant magnetostrictive materials. The design principle of the actuator was firstly analyzed, which consists of the analysis of giant magnetostrictive materials and a force generator. Then the design criterion of magnetostrictive actuators was deeply discussed, which includes the dimension design of magnetostrictive materials, the design of magnetic field and the design of elimination of heat. Finally, a real actuator was developed, which has been used in the high frequency VSR. The experimental results show that the developed actuator works very well. Large exciting force but small vibration amplitude will make it widely used in the VSR.

  15. Vibratory synchronization transmission of a cylindrical roller in a vibrating mechanical system excited by two exciters

    Science.gov (United States)

    Zhang, Xueliang; Wen, Bangchun; Zhao, Chunyu

    2017-11-01

    In present work vibratory synchronization transmission (VST) of a cylindrical roller with dry friction in a vibrating mechanical system excited by two exciters, is studied. Using the average method, the criterion of implementing synchronization of two exciters and that of ensuring VST of a roller, are achieved. The criterion of stability of the synchronous states satisfies the Routh-Hurwitz principle. The influences of the structural parameters of the system to synchronization and stability, are discussed numerically, which can be served as the theoretical foundation for engineering designs. An experiment is carried out, which approximately verify the validity of the theoretical and numerical results, as well as the feasibility of the method used. Utilizing the VST theory of a roller, some types of vibrating crushing or grinding equipments, etc., can be designed.

  16. Gyroscope with two-dimensional optomechanical mirror

    Science.gov (United States)

    Davuluri, Sankar; Li, Kai; Li, Yong

    2017-11-01

    We propose an application of two-dimensional optomechanical oscillator as a gyroscope by detecting the Coriolis force which is modulated at the natural frequency of the optomechanical oscillator. Dependence of gyroscope's sensitivity on shot noise, back-action noise, thermal noise, and input laser power is studied. At optimal input laser power, the gyroscope's sensitivity can be improved by increasing the mass or by decreasing the temperature and decay rate of the mechanical oscillator. When the mechanical oscillator's thermal occupation number, n th, is zero, sensitivity improves with decrease in frequency of the mechanical oscillator. For {n}{{th}}\\gg 1, the sensitivity is independent of the mechanical oscillator's frequency.

  17. Carbon Nanotube Tape Vibrating Gyroscope

    Science.gov (United States)

    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.

  18. Miniaturized High Performance Optical Gyroscope Project

    Data.gov (United States)

    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...

  19. MEMS Gyroscope with Interferometric Detection Project

    Data.gov (United States)

    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...

  20. MEMS Gyroscope with Interferometric Detection Project

    Data.gov (United States)

    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...

  1. Model Design of Piezoelectric Micromachined Modal Gyroscope

    Directory of Open Access Journals (Sweden)

    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.

  2. Integrated microelectromechanical gyroscope under shock loads

    Science.gov (United States)

    Nesterenko, T. G.; Koleda, A. N.; Barbin, E. S.

    2018-01-01

    The paper presents a new design of a shock-proof two-axis microelectromechanical gyroscope. Without stoppers, the shock load enables the interaction between the silicon sensor elements. Stoppers were installed in the gyroscope to prevent the contact interaction between electrodes and spring elements with fixed part of the sensor. The contact of stoppers occurs along the plane, thereby preventing the system from serious contact stresses. The shock resistance of the gyroscope is improved by the increase in its eigenfrequency at which the contact interaction does not occur. It is shown that the shock load directed along one axis does not virtually cause the movement of sensing elements along the crosswise axes. Maximum stresses observed in the proposed gyroscope at any loading direction do not exceed the value allowable for silicon.

  3. Nonlinear oscillations in coriolis based gyroscopes

    Directory of Open Access Journals (Sweden)

    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.

  4. Fabrication of a novel quartz micromachined gyroscope

    Science.gov (United States)

    Xie, Liqiang; Xing, Jianchun; Wang, Haoxu; Wu, Xuezhong

    2015-04-01

    A novel quartz micromachined gyroscope is proposed in this paper. The novel gyroscope is realized by quartz anisotropic wet etching and 3-dimensional electrodes deposition. In the quartz wet etching process, the quality of Cr/Au mask films affecting the process are studied by experiment. An excellent mask film with 100 Å Cr and 2000 Å Au is achieved by optimization of experimental parameters. Crystal facets after etching seriously affect the following sidewall electrodes deposition process and the structure's mechanical behaviours. Removal of crystal facets is successfully implemented by increasing etching time based on etching rate ratios between facets and crystal planes. In the electrodes deposition process, an aperture mask evaporation method is employed to prepare electrodes on 3-dimensional surfaces of the gyroscope structure. The alignments among the aperture masks are realized by the ABM™ Mask Aligner System. Based on the processes described above, a z-axis quartz gyroscope is fabricated successfully.

  5. Gyroscopic stabilization and indefimite damped systems

    DEFF Research Database (Denmark)

    Pommer, Christian

    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...... the stabilty limit for pure dissipative systems as well as for dissipative systems with gyroscopic stabilization....

  6. Hemispherical Resonator Gyroscope Accuracy Analysis Under Temperature Influence

    Directory of Open Access Journals (Sweden)

    Boran LI

    2014-06-01

    Full Text Available Frequency splitting of hemispherical resonator gyroscope will change as system operating temperature changes. This phenomenon leads to navigation accuracy of hemispherical resonator gyroscope reduces. By researching on hemispherical resonator gyroscope dynamical model and its frequency characteristic, the frequency splitting formula and the precession angle formula of gyroscope vibrating mode based on hemispherical resonator gyroscope dynamic equation parameters are derived. By comparison, gyroscope precession angle deviation caused by frequency splitting can be obtained. Based on analysis of temperature variation against gyroscope resonator, the design of hemispherical resonator gyroscope feedback controller under temperature variation conditions is researched and the maximum theoretical fluctuation of gyroscope dynamical is determined by using a numerical analysis example.

  7. The dynamics of cavity clusters in ultrasonic (vibratory) cavitation erosion

    DEFF Research Database (Denmark)

    Hansson, I.; Mørch, Knud Aage

    1980-01-01

    The erosion of solids caused by cavitating liquids is a result of the concerted collapse of clusters of cavities. In vibratory cavitation equipment the clusters grow and collapse adjacent to a solid surface and are typically of hemispherical or cylindrical form. In the present paper the collapse...... process of these clusters is described and the collapse equations are developed and solved. The theoretical results are compared with results from high-speed photography of the clusters and with the initial stages of cavitation erosion on metal specimens. Experimental and theoretical results show...

  8. Used Furan Sand Reclamation in REGMAS Vibratory Unit

    Directory of Open Access Journals (Sweden)

    Dańko J.

    2015-09-01

    Full Text Available The paper, especially dealt with problems of reclamation of used furan sand, carried out in new, vibratory sand reclamation unit REGMAS developed by researches from AGH-University of Science and Technology, Faculty of Foundry Engineering in Cracow (Poland. Functional characteristics of reclamation unit as well as the results of reclamation of used sand with furfuryl resin are discussed in the paper. The quality of reclaim was tested by means of the LOI and pH value, dust content in the reclaim and at least by the the quality of the castings produced in moulds prepared with the use of reclaimed matrix.

  9. Dispersion-Enhanced Laser Gyroscope

    Science.gov (United States)

    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.

  10. Field Tests to Investigate the Penetration Rate of Piles Driven by Vibratory Installation

    Directory of Open Access Journals (Sweden)

    Zhaohui Qin

    2017-01-01

    Full Text Available Factors directly affecting the penetration rate of piles installed by vibratory driving technique are summarized and classified into seven aspects which are driving force, resistance, vibratory amplitude, energy consumption, speeding up at the beginning, pile plumbness keeping, and slowing down at the end, from the mechanism and engineering practice of the vibratory pile driving. In order to find out how these factors affect the penetration rate of the pile in three major actors of vibratory pile driving: (i the pile to be driven, (ii the selected driving system, and (iii the imposed soil conditions, field tests on steel sheet piles driven by vibratory driving technique in different soil conditions are conducted. The penetration rates of three different sheet pile types having up to four different lengths installed using two different vibratory driving systems are documented. Piles with different lengths and types driven with or without clutch have different penetration rates. The working parameters of vibratory hammer, such as driving force and vibratory amplitude, have great influences on the penetration rate of the pile, especially at the later stages of the sinking process. Penetration rate of piles driven in different soil conditions is uniform because of the different penetration resistance including shaft friction and toe resistance.

  11. A novel demodulation method in MEMS gyroscope

    Science.gov (United States)

    Sung, Woon-Tahk; Lee, Jang Gyu; Kang, Taesam

    2005-12-01

    This paper presents a novel approach for demodulation method of signal processing circuit in MEMS gyroscope. Since the MEMS gyroscope utilizes Coriolis acceleration that produces a modulated signal of the input angular velocity and driving signal, in order to measure the original angular rate, the demodulation process is essentially needed. The conventional AM demodulation process in MEMS gyroscope is sensitive to the phase difference between the output signal and the modulation reference signal. Moreover, the output is easily affected by nonlinear and noisy properties of a multiplying circuit. Proposed method eliminates the phase tuning of the demodulation stage and the multiplying process of the signal processing circuit that are likely to be major error factors of signal processing circuit but are essential parts of the conventional demodulation process in MEMS gyroscope. The proposed method utilized the envelope detection scheme of AM demodulation in communication system and modified it to apply to the electromechanical system of gyroscope. Experiments were accomplished to verify the performances. From the results, the proposed method shows a satisfactory performance without a multiplying component and tuning effort of the phase in signal process circuit.

  12. 14 CFR 23.371 - Gyroscopic and aerodynamic loads.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Gyroscopic and aerodynamic loads. 23.371... Flight Loads § 23.371 Gyroscopic and aerodynamic loads. (a) Each engine mount and its supporting structure must be designed for the gyroscopic, inertial, and aerodynamic loads that result, with the engine...

  13. Mechanical Coupling Error Suppression Technology for an Improved Decoupled Dual-Mass Micro-Gyroscope.

    Science.gov (United States)

    Yang, Bo; Wang, Xingjun; Deng, Yunpeng; Hu, Di

    2016-04-08

    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.

  14. Fibre optic gyroscope with single-mode fibre and loop-back phase shift compensation

    Science.gov (United States)

    Skalský, Michal; Havránek, Zdeněk.; Fialka, Jiří

    2017-12-01

    An all-fibre optical sensor of an angular velocity (fibre-optic gyroscope) based on the Sagnac interferometer and using a loop-back phase shift compensation is presented. The sensing loop consists of 760 metres of an ordinary single-mode fibre, which makes this setup cost-effective. To ensure principles of beams reciprocity, randomly induced changes of polarization in the fibre are reduced by using an unpolarized light. This is achieved by a fibre Lyot depolarizer and a super fluorescent fibre source consisting of an erbium-doped fibre pumped by a laser diode. Unlike common approaches to the unpolarized fibre-optic gyroscope with a single-mode fibre, whose output is naturally nonlinear, we use a loop-back compensation of a rotation-induced phase shift to achieve a linear response. In most cases, this technique requires fast electro-optical modulator, which is compatible only with an expensive polarization-maintaining fibre. We use a novel loop-back modulation scheme utilizing only harmonic signals and thus compatible with a piezoelectric fibre stretcher, which can be used with any kind of optical fibre. As result of the closed-loop operation, the range of the gyroscope's linearity is greatly increased and a sensitivity to source power changes is suppressed. We describe the gyroscope setup with proposed modulation method and provide a comparison to the common open-loop setup.

  15. Mechanical Coupling Error Suppression Technology for an Improved Decoupled Dual-Mass Micro-Gyroscope

    Directory of Open Access Journals (Sweden)

    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.

  16. Polhode dynamics and gyroscope asymmetry analysis of Gravity Probe B using gyroscope position data

    Science.gov (United States)

    Dolphin, Michael D. M.

    2007-12-01

    Gravity Probe B is a joint NASA/Stanford University satellite-based experiment designed to measure two predictions of Einstein's General Theory of Relativity: the geodetic and frame-dragging effects. The two effects are predicted to cause spin axis drift of a gyroscope with respect to the fixed stars at a rate of 3.203 x10-5 and 1.89x10-7 radians (6606 and 39 milli-arcseconds) per year, respectively. The frame-dragging effect has not previously been observed experimentally. The sensors for this experiment are four round gyroscopes of radius 19 mm, spherical to within 20 nm for largest peak to valley distance on their surface. For the success of the mission, it is essential that the measurement of the spin axis orientation be both precise and accurate to within 5 nrad. Polhode motion is a well understood motion of a body rotating in a torque-free environment. It was believed that the polhode motion would remain constant over the course of the mission. Early in the data analysis it was revealed that the polhode motion changed its behavior over time. To obtain the accuracy desired for the mission, a detailed understanding of the polhode behavior for each of the four gyroscopes is required. The main focus of this research is to understand and fully characterize the polhode motion. Analysis of the equations reveals that one parameter characterizes the shape of the polhode path, designated as Q. The exact timing of the polhode behavior is captured in the analysis of the polhode phase. To obtain an estimate of Q and the polhode phase, the gyroscope suspension system data is analyzed to reveal variations of measured gyroscope position at spin frequency. A model of the gyroscopes' surface shape is created and used to find the most likely value of Q by means of a multi parameter search. The value for Q is obtained to an accuracy of 0.05 for two of the gyroscopes. The parameters defining the gyroscopes' surface shape are obtained to within sub nanometer levels for all four

  17. Climate Change and Some Other Implications of Vibratory Existence

    Directory of Open Access Journals (Sweden)

    Glenn McLaren

    2009-11-01

    Full Text Available Modern Process Philosophy began when Alfred North Whitehead realized that existence is primarily vibratory, not points but processes. Vibrations are best understood as sound waves, or through using auditory metaphors rather than visual ones. Our Universe is more like music than matter, but how does this help us better understand it? In this paper I use the example of the large ocean current oscillators that help drive our climate systems to reveal the more effective nature of auditory approaches. Through an auditory approach, we can better understand the ways these oscillations constrain and interact with other levels of oscillations as well as how they might be destroyed by other levels. This can then lead to us extending our ethics to the conservation of these oscillations.

  18. Single-layer silicon-on-insulator MEMS gyroscope for wide dynamic range and harsh environment applications

    Science.gov (United States)

    Kranz, Michael S.; Hudson, Tracy D.; Ashley, Paul R.; Ruffin, Paul B.; Burgett, Sherrie J.; Temmen, Mark; Tuck, Jerry

    2001-10-01

    The Army Aviation and Missile Command (AMCOM), Morgan Research Corporation, and Aegis Research Corporation are developing an SOI-based vibratory-rate z-axis MEMS gyroscope utilizing force-feedback control, and intended for wide dynamic range and harsh environment applications. Rate sensing in small diameter ballistic missile guidance units requires a rate resolution of less than 1 degree(s)/hr over a range of -3000 to +3000 degree(s)/sec, resulting in a dynamic range of 107. In addition, the devices must operate through military specifications on temperature (-55 degree(s)C to +125 degree(s)C) and vibration (1000 g at 5 - 15 kHz). This paper presents modeling, simulation, and fabrication efforts, as well as initial test data, for an SOI-based rate sensor intended for this application. The prototyped gyroscope is a single layer structure consisting of a proof mass placed in a three-fold mode-decoupled symmetric suspension. The device is fabricated in a cost-effective and highly-controllable Silicon-on-Insulator (SOI) process for in-plane inertial devices. The mechanical structure is integrated in a vacuum-sealed hermetic package with a separate CMOS readout ASIC. At the present time, the device has undergone two design iterations, with the most recent just completed.

  19. Gyroscopic Stabilization of Indefinite Damped Systems

    DEFF Research Database (Denmark)

    Kliem, Wolfhard; Müller, Peter C.

    1997-01-01

    Modelling of mechanical systems with sliding bearings, or with dry friction, can lead to linear systems with an indefinite damping matrix. We ask under what conditions such a system is unstable (the indefiniteness of the damping matrix is not enough) and under what conditions we can stabilize the...... the system by adding a gyroscopic term....

  20. A Dual-Butterfly Structure Gyroscope.

    Science.gov (United States)

    Xu, Xiangming; Xiao, Dingbang; Li, Wenyin; Xu, Qiang; Hou, Zhanqiang; Wu, Xuezhong

    2017-12-11

    This paper reports a dual-butterfly structure gyroscope based on the traditional butterfly structure. This novel structure is composed of two butterfly structures, each of which contains a main vibrational beam, four proof masses, and a coupling mechanism. The coupling mechanism in this proposed structure couples the two single butterfly structures and keeps the driving mode phases of the two single butterfly gyroscopes exactly opposite, increasing the double difference of traditional butterfly gyroscopes to a quad difference, which has the potential advantage of improving bias instability and g-sensitivity. The gyroscope was fabricated using a standard microfabrication method and tested in laboratory conditions. The experimental results show a Q-factor of 10,967 in driving mode and there were two peaks in the frequency responses curve of sensing direction due to unavoidable fabrication errors. Scale factor and bias instability were also measured, reaching a scale factor of 10.9 mV/°/s and a bias instability of 10.7°/h, according to the Allan Variance curve.

  1. The Numerical FEM Model of the Kinematics of the Vibratory Shot Peening Process

    Directory of Open Access Journals (Sweden)

    Stanisław Bławucki

    2017-12-01

    Full Text Available The paper presents the results of numerical calculations, with the finite element method in the ABAQUS program environment, of the vibratory shot peening process with loose peening elements. The behaviour of shot peening elements was analysed in the kinematic aspect. The impact of the initial deployment of vibratory shot peening elements on their behaviour during processing was investigated, including the displacement, velocity, acceleration and the number of collisions. The way of determining the effectiveness of the processing with the vibratory shot peening was illustrated.

  2. Electroejaculation versus vibratory stimulation in spinal cord injured men: sperm quality and patient preference.

    Science.gov (United States)

    Ohl, D A; Sønksen, J; Menge, A C; McCabe, M; Keller, L M

    1997-06-01

    We compared semen quality and patient preference between penile vibratory stimulation and electroejaculation in spinal cord injured men. We treated 11 spinal cord injured men with penile vibratory stimulation and electroejaculation in random order. End points examined were semen analysis, sperm functional assessment, and patient pain scores (1 to 10) and preferred procedure. Differences between the procedures were determined with the paired Student t test. There was no difference in antegrade sperm count but penile vibratory stimulation specimens had greater motility (26.0 versus 10.7%), viability (25.2 versus 9.7%) and motile sperm count (185.0 x 10(6) versus 97.0 x 10(6)). The retrograde sperm count was greater (but not significant) in electroejaculation patients. The total (antegrade plus retrograde) and motile sperm counts were not different. There was no difference in immunobead test (all negative), cervical mucus penetration or sperm penetration assay, although the percent hamster egg penetration approached significance (53.7% for penile vibratory stimulation versus 22.1% for electroejaculation, p = 0.06). There was no difference in the peak blood pressures and no complications were noted. Pain scores were significantly greater for electroejaculation compared to penile vibratory stimulation (5.2 versus 1.7, respectively). All patients preferred penile vibratory stimulation. There was a slight advantage in sperm quality and a high patient preference in favor of penile vibratory stimulation. Penile vibratory stimulation should be attempted first to induce ejaculation in spinal cord injured men, with electroejaculation reserved for failures.

  3. Sphincteric events during penile vibratory ejaculation and electroejaculation in men with spinal cord injuries.

    Science.gov (United States)

    Sønksen, J; Ohl, D A; Wedemeyer, G

    2001-02-01

    We investigate internal and external sphincter responses during penile vibratory stimulation and electroejaculation in men with spinal cord injury. Ejaculation induction with simultaneous recording of external and internal sphincter pressures was performed in 9 spinal cord injured men. Of the patients with upper motor neuron lesions 3 underwent penile vibratory stimulation and 3 underwent electroejaculation. In 3 men who did not respond to PVS, including 1 with upper motor neuron and 2 with lower motor neuron lesions, penile vibratory stimulation and subsequent electroejaculation were performed. In successful penile vibratory stimulation and electroejaculation upper motor neuron cases external sphincter pressure first reached a peak (average 180 cm. H2O) and subsequently decrease followed in 3 to 10 seconds by a peak in internal sphincter pressure (average 178 cm. H2O), which exceeded external sphincter pressure and ejaculation occurred. During electroejaculation, the pattern progressed, despite complete discontinuation of electrical stimulation. In electroejaculation, there was a trend for a more rapid return of external sphincter pressure greater than internal sphincter pressure, which may explain the electroejaculation retrograde fraction. In nonresponders external sphincter pressure never increased to more than 105 cm. H2O in response to penile vibratory stimulation and no ejaculation was induced. In nonresponders to penile vibratory stimulation, electroejaculation induced a typical sustained increase in internal sphincter pressure and external sphincter pressure but at lower peak pressures. Forceful contraction of the external sphincter followed by contraction of the internal sphincter always precedes ejaculation during electroejaculation and penile vibratory stimulation. Similarities between penile vibratory stimulation and electroejaculation suggest that the latter induces ejaculation via a complex neurological pathway rather than by simple direct end organ

  4. Jean-Martin Charcot and his vibratory chair for Parkinson disease.

    Science.gov (United States)

    Goetz, Christopher G

    2009-08-11

    Vibration therapy is currently used in diverse medical specialties ranging from orthopedics to urology to sports medicine. The celebrated 19th-century neurologist, J.-M. Charcot, used vibratory therapy to treat Parkinson disease (PD). This study analyzed printed writings by Charcot and other writers on vibratory therapy and accessed unpublished notes from the Salpêtrière Hospital, Paris. Charcot lectured on several occasions on vibratory therapy and its neurologic applications. He developed a vibration chair for patients with PD after he observed that patients were more comfortable and slept better after a train or carriage ride. He replicated this experience by having patients undergo daily 30-minute sessions in the automated vibratory chair (fauteuil trépidant). His junior colleague, Gilles de la Tourette, extended these observations and developed a helmet that vibrated the head on the premise that the brain responded directly to the pulsations. Although after Charcot's death vibratory therapy was not widely pursued, vibratory appliances are reemerging in 21st century medicine and can be retested using adaptations of Charcot's neurologic protocols.

  5. Vocal fold vibratory characteristics of healthy geriatric females--analysis of high-speed digital images.

    Science.gov (United States)

    Ahmad, Kartini; Yan, Yuling; Bless, Diane

    2012-11-01

    A high proportion of the geriatric population suffers from presbylaryngis and presbyphonia; however, our knowledge of vibratory patterns in this population is almost nonexistent. In this study, we investigate the vocal fold vibratory patterns of healthy elderly females to determine which features or combination of them could best describe the geriatric voices. Cross-sectional study with 20 elderly healthy females with no history of voice problems. Hilbert transformed glottal area waveforms (GAWs) from serial high-speed digital imaging of sustained phonation are used to provide quantitative measures of glottal vibratory characteristics and perturbations; open quotient, jitter, and shimmer. Nyquist plots provide interpretable patterns to portray the vibratory characteristics as clear, pressed, breathy, and atypical patterns. The GAW from most elderly speakers (50%) showed vibratory characteristics associated with a more pressed voice and higher glottal perturbation values: their Nyquist plot patterns show wide scatterings around the rim of the plot reflecting a much-reduced ability in sustaining vibratory oscillation; these were distinct differences from previously reported data on younger speakers. Qualitative examination revealed more anteriorly placed glottal gaps in the geriatric females. These findings have important implications in understanding voice production in the geriatric population and in helping to establish normal perturbation references among female speakers across age. Copyright © 2012 The Voice Foundation. All rights reserved.

  6. Semen quality of spinal cord injured men is better when obtained by vibratory stimulation versus electroejaculation.

    Science.gov (United States)

    Brackett, N L; Padron, O F; Lynne, C M

    1997-01-01

    Most spinal cord injured men require assisted ejaculation procedures to obtain semen, and the majority can achieve this result by vibratory stimulation or electroejaculation. We determined if semen obtained by vibratory stimulation differed in quality from that obtained by electroejaculation. Between subjects and within subjects designs were used. Of 77 spinal cord injured men 23 underwent vibratory stimulation only, 44 electroejaculation only and 10 both procedures. Antegrade, retrograde and total ejaculates were analyzed in each subject for total sperm count, percent motile sperm and percent sperm with rapid linear motion. With vibratory stimulation compared to electroejaculation the percent motile sperm and percent sperm with rapid linear motion were significantly greater, whereas total sperm count was similar, in the antegrade specimens and total ejaculates. This finding was true for different groups of subjects as well as within a group of the same subjects. Semen obtained by vibratory stimulation is of better quality than that obtained by electroejaculation. In medical practices that include assisted ejaculation of spinal cord injured men, we recommend obtaining a specimen by vibratory stimulation. If that method fails electroejaculation should be performed.

  7. Review on Development of Fault Diagnosis for Gyroscope

    OpenAIRE

    Song He; Hu Shao-Lin; Zhou Ke-Yi

    2017-01-01

    Gyroscope is a core part of navigation system, whose working stability and reliability directly affects the navigation performance of navigation system. Therefore, in order to ensure the precision and reliability of navigation system, it is very important to develop the techniques of fault diagnosis for gyroscope. First, the development of gyroscope’s history and the background and significance of fault diagnosis for gyroscope is introduced in this paper. Then, the influence factors of abnorm...

  8. Vibratory device for taking ocean floor sediment cores

    Energy Technology Data Exchange (ETDEWEB)

    Edigariav, Z.P.; Kudinov, E.I.; Sukhov, V.E.

    1973-04-04

    The present invention relates to devices for taking sediment cores from the ocean floor. It consists in a vibratory device, comprising a string of pipe, a vibrator disposed on the string of pipe for sinking the pipe into the ocean floor, an arrangement for providing for periodical engagement and disengagement of the vibrator with the string of pipe, a hoist providing for periodical displacement of the vibrator, which is originally disposed on the lower portion of the string of pipe, up the string as the latter is being sunk into the ocean floor, and operatively coupled with the engaging arrangement. A piston is freely displaceable in the string of pipe and fixed relative to the ocean floor when the pipe is being sunk, to retain the ocean floor sediments in the pipe. The core of sediment is pressed against the piston under the action of hydrostatic and atmospheric pressures. A system is provided for stabilizing the device consisting of a load platform, a float, and guide cables. (6 claims)

  9. Analysis of the Gyroscopic Stability of the Wheelset

    Directory of Open Access Journals (Sweden)

    Hao Dong

    2014-01-01

    Full Text Available The wheelset of the railway vehicle is a rotor which itself has gyroscopic effect. Nowadays, the rolling stock has entered the era of high speed, and the wheel rotates faster than in the past. The influence of gyroscopic effect on stability is little understood. Metelitsyn’s inequality theorem for asymptotic stability has some advantages to analyze this problem although this method is sufficient but not necessary condition. Based on its deduction, the extremal eigenvalues criterion and compared with Routh-Hurwitz criterion, both are applied to solve the critical value of speed. Further, according to the instability criterion, gyroscopic contributory ratio is derived to study how the role the gyroscopic effect plays in stability. Moreover, the effect of gyroscopic matrix or gyroscopic terms pitch rotor inertia Iy on stability coefficient is investigated. The results show that Iy is a key factor to wheelset gyroscopic stability. The gyroscopic effect becomes significant, and the stability increases with increasing Iy. The results also indicate that the critical value of speed solved by Metelitsyn theorem is more conservative than the one it solved by Hurwitz criterion, which proves that Metelitsyn inequality theorem for asymptotic stability is a sufficient but not necessary condition in the way of attaining the numerical simulation result. Finally, the test for the influence of gyroscopic effect on stability needs to be further studied.

  10. Gyroscopic Inertial Micro-Balance Azimuth Locator (GIMBAL) Project

    Data.gov (United States)

    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...

  11. A novel MEMS S-springs vibrating ring gyroscope with atmosphere package

    Science.gov (United States)

    Kou, Zhiwei; Liu, Jun; Cao, Huiliang; Shi, Yunbo; Ren, Jianjun; Zhang, Yingjie

    2017-12-01

    This study presents a new MEMS vibrating ring gyroscope (VRG), which is driven by electrostatic force and detected by capacitance. A novel ring resonator with eight S-shaped symmetrical supporting springs is developed based on the advantageous characteristics of a thin-shell vibrating gyroscope. The capacitance electrodes, including the drive electrodes, the sense electrodes and the mode control electrodes, are designed according to the vibration characteristics of the ring resonator and the shape of the supporting springs. In addition, the operational principle of these electrode capacitors and the electrostatic force of the drive electrodes are discussed in detail. The gyroscope with high aspect-ratio structures is manufactured through an efficient fabrication process. Finally, the performance characteristics of the fabricated VRG are tested, and the experimentally obtained the zero-bias instability is about 0.0167°/s and angle random walk (ARW) is about 0.1363°/s1/2 at room temperature. Experimental results show that the VRG has a simple structure and relatively better performance characteristics for low and medium angular velocity measurements.

  12. A novel MEMS S-springs vibrating ring gyroscope with atmosphere package

    Directory of Open Access Journals (Sweden)

    Zhiwei Kou

    2017-12-01

    Full Text Available This study presents a new MEMS vibrating ring gyroscope (VRG, which is driven by electrostatic force and detected by capacitance. A novel ring resonator with eight S-shaped symmetrical supporting springs is developed based on the advantageous characteristics of a thin-shell vibrating gyroscope. The capacitance electrodes, including the drive electrodes, the sense electrodes and the mode control electrodes, are designed according to the vibration characteristics of the ring resonator and the shape of the supporting springs. In addition, the operational principle of these electrode capacitors and the electrostatic force of the drive electrodes are discussed in detail. The gyroscope with high aspect-ratio structures is manufactured through an efficient fabrication process. Finally, the performance characteristics of the fabricated VRG are tested, and the experimentally obtained the zero-bias instability is about 0.0167°/s and angle random walk (ARW is about 0.1363°/s1/2 at room temperature. Experimental results show that the VRG has a simple structure and relatively better performance characteristics for low and medium angular velocity measurements.

  13. Interference of Overlapping Insect Vibratory Communication Signals: An Eushistus heros Model.

    Directory of Open Access Journals (Sweden)

    Andrej Čokl

    Full Text Available Plants limit the range of insect substrate-borne vibratory communication by their architecture and mechanical properties that change transmitted signal time, amplitude and frequency characteristics. Stinkbugs gain higher signal-to-noise ratio and increase communication distance by emitting narrowband low frequency vibratory signals that are tuned with transmission properties of plants. The objective of the present study was to investigate hitherto overlooked consequences of duetting with mutually overlapped narrowband vibratory signals. The overlapped vibrations of the model stinkbug species Eushistus heros, produced naturally or induced artificially on different plants, have been analysed. They represent female and male strategies to preserve information within a complex masked signal. The brown stinkbugs E. heros communicate with species and gender specific vibratory signals that constitute characteristic duets in the calling, courtship and rivalry phases of mating behaviour. The calling female pulse overlaps the male vibratory response when the latency of the latter is shorter than the duration of the female triggering signal or when the male response does not inhibit the following female pulse. Overlapping of signals induces interference that changes their amplitude pattern to a sequence of regularly repeated pulses in which their duration and the difference between frequencies of overlapped vibrations are related inversely. Interference does not occur in overlapped narrow band female calling pulses and broadband male courtship pulse trains. In a duet with overlapped signals females and males change time parameters and increase the frequency difference between signals by changing the frequency level and frequency modulation pattern of their calls.

  14. An Integrated MEMS Gyroscope Array with Higher Accuracy Output

    Science.gov (United States)

    Chang, Honglong; Xue, Liang; Qin, Wei; Yuan, Guangmin; Yuan, Weizheng

    2008-01-01

    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 first-level 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. PMID:27879855

  15. Coupled Thermal Field of the Rotor of Liquid Floated Gyroscope

    Directory of Open Access Journals (Sweden)

    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.

  16. Noise Reduction of MEMS Gyroscope Based on Direct Modeling for an Angular Rate Signal

    Directory of Open Access Journals (Sweden)

    Liang Xue

    2015-02-01

    Full Text Available 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 without needing other sensor’s information, whether in static or dynamic condition. A linear fit equation that describes the relationship between the KF bandwidth and modeling parameter of true angular rate was derived from the analysis of KF frequency response. The test results indicated that the MEMS gyroscope having an ARW noise of 4.87°/h0.5 and a bias instability of 44.41°/h were reduced to 0.4°/h0.5 and 4.13°/h by the KF under a given bandwidth (10 Hz, respectively. The 1σ estimated error was reduced from 1.9°/s to 0.14°/s and 1.7°/s to 0.5°/s in the constant rate test and swing rate test, respectively. It also showed that the filtered angular rate signal could well reflect the dynamic characteristic of the input rate signal in dynamic conditions. The presented algorithm is proved to be effective at improving the measurement precision of the MEMS gyroscope.

  17. Structure optimization and simulation analysis of the quartz micromachined gyroscope

    Directory of Open Access Journals (Sweden)

    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.

  18. Gait event detection during stair walking using a rate gyroscope.

    Science.gov (United States)

    Formento, Paola Catalfamo; Acevedo, Ruben; Ghoussayni, Salim; Ewins, David

    2014-03-19

    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.

  19. Precession and nutation of a gyroscope

    Science.gov (United States)

    Butikov, Eugene

    2006-09-01

    A simple treatment of the important old problem of the torque-induced rotation of a spinning symmetrical top is suggested. Our discussion is appropriate for teaching introductory mechanics and general physics to undergraduate students and is free from the difficulties of a traditional approach to the problem. The origin of nutation that accompanies forced precession is explained in detail, with an accent on its relationship to the torque-free precession of a symmetrical body. A small simulation program is developed that visualizes the investigated motion and illustrates its principal features. The program facilitates understanding about the counterintuitive behaviour of a gyroscope on a qualitative level.

  20. Gyroscopically Stabilized Robot: Balance and Tracking

    Directory of Open Access Journals (Sweden)

    Yongsheng Ou

    2004-03-01

    Full Text Available The single wheel, gyroscopically stabilized robot - Gyrover, is a dynamically stable but statically unstable, underactuated system. In this paper, based on the dynamic model of the robot, we investigate two classes of nonholonomic constraints associated with the system. Then, based on the backstepping technology, we propose a control law for balance control of Gyrover. Next, through transferring the systems states from Cartesian coordinate to polar coordinate, control laws for point-to-point control and line tracking in Cartesian space are provided.

  1. The effect of penile vibratory stimulation on male fertility potential, spasticity and neurogenic detrusor overactivity in spinal cord lesioned individuals

    DEFF Research Database (Denmark)

    Biering-Sørensen, F; Læssøe, Line; Sønksen, J

    2005-01-01

    Present the possibility for treatment of male infertility, spasticity, and neurogenic detrusor overactivity in spinal cord lesioned (SCL) individuals with penile vibratory stimulation (PVS).......Present the possibility for treatment of male infertility, spasticity, and neurogenic detrusor overactivity in spinal cord lesioned (SCL) individuals with penile vibratory stimulation (PVS)....

  2. Structural Calculations of Drip Shield Exposed to Vibratory Ground Motion

    Energy Technology Data Exchange (ETDEWEB)

    S. Mastilovic

    2003-06-16

    The objective of this calculation is twofold. First, to determine whether or not separation of interlocking drip shield (DS) segments occurs during vibratory ground motion. Second, if DS separation does not occur, to estimate the area of the DS for which the residual 1st principal stress exceeds a certain limit. (The area of DS plate-1 and DS plate-2 [see Attachment I] where the residual 1st principal stress exceeds a certain limit will be, for brevity, referred to as ''the damaged area'' throughout this document; also, DS plate-1 and DS plate-2 will be referred to, for brevity, as ''DS plates'' henceforth.) The stress limit used throughout this document is defined as 50 percent of yield strength of the DS plate material, Titanium Grade 7 (Ti-7) (SB-265 R52400), at temperature of 150 C. A set of 15 calculations is performed at two different annual frequencies of occurrence (annual exceedance frequency): 10{sup -6} per year (1/yr) and 10{sup -7} 1/yr . (Note: Due to computational problems only five realizations at 10{sup -7} 1/yr are presented in this document.) Additionally, one calculation is performed at the annual frequency of occurrence of 5 {center_dot} 10{sup -4} 1/yr. The scope of this document is limited to reporting whether or not the DS separation occurs. If the DS separation does not occur the scope is limited to reporting the calculation results in terms of the damaged area. All these results are evaluated for the DS plates. This calculation is intended for use in support of the Total System Performance Assessment-License Application seismicity modeling. This calculation is associated with the DS design and was performed by the Waste Package Design group. AP-3.12Q, ''Design Calculations and Analyses'' (Ref. 1) is used to perform the calculation and develop the document. The DS is classified as Quality Level 1 (Ref. 5, p. 7). Therefore, this calculation is subject to the Quality Assurance

  3. Fibre optic gyroscopes for space use

    Science.gov (United States)

    Faussot, Nicolas; Cottreau, Yann; Hardy, Guillaume; Simonpietri, Pascal; Gaiffe, Thierry

    2017-11-01

    Among the technologies available for gyroscopes usable in space, the Fibre Optic Gyroscope (FOG) technology appears to be the most suitable: no moving parts, very good lifetime, low power consumption, very low random walk, arbitrarily low angular resolution and very good behaviour in radiations and vacuum. Benefiting from more than ten years of experience with this technology, Ixsea (formerly the Navigation Division of Photonetics) is developing space FOG under both CNES and ESA contracts since many years. In the 1996-1998 period, two space FOG demonstrators in the 0,01°/h class were manufactured, including an optical head (optic and optoelectronic part) designed for space use and a standard ground electronics. Beyond the demonstration of the specified FOG performances, the behaviour of the optical head has been validated for use in typical space environment: vibrations, shocks, radiations (up to 50 krad) and thermal vacuum. Since the beginning of 1999, Ixsea is developing a space electronics in order to manufacture two complete space FOG. The first one entered in qualification in October. The second one will be delivered beginning of next year, it will be used in a CNES attitude measurement experiment (MAGI) onboard the FrenchBrazilian Microsatellite (FBM) partly dedicated to technology evaluation.

  4. Space Station Control Moment Gyroscope Lessons Learned

    Science.gov (United States)

    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.

  5. A novel differential frequency micro-gyroscope

    KAUST Repository

    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.

  6. A Micro Dynamically Tuned Gyroscope with Adjustable Static Capacitance

    Directory of Open Access Journals (Sweden)

    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.

  7. The Gravity Probe B electrostatic gyroscope suspension system (GSS)

    Science.gov (United States)

    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.

  8. Modeling and Formulation of a Novel Microoptoelectromechanical Gyroscope

    Directory of Open Access Journals (Sweden)

    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(xmax⁡Qy/ωyΩ(tsin⁡(ωdt, (2 relation between rotation and interferometric intensity of light I(t≈(8π/λ(xmax⁡Qy/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.

  9. Online camera-gyroscope autocalibration for cell phones.

    Science.gov (United States)

    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.

  10. Ultraviolet-LIGA-based fabrication and characterization of a nonresonant drive-mode vibratory gyro/accelerometer

    Science.gov (United States)

    Verma, Payal; Zaman Khan, Khamar; Khonina, Svetlana Nikolaevna; Kazanskiy, Nikolay Lvovich; Gopal, Ram

    2016-07-01

    A dual-purpose nonresonant 2-degrees of freedom (DOF) drive-mode and 1-DOF sense-mode vibratory gyro/accelerometer fabricated using the economical ultraviolet-lithographie-galvanoformung-abformung (UV-LIGA) fabrication process using SU-8 photoresist is reported. The dual-purpose device presented is capable of detecting acceleration at the lower-frequency band and angular rate at the operating frequency band thereby functioning as both accelerometer and gyroscope. This is achieved by designing the structure such that the frequency response of the drive oscillator has two drive resonances with a flat zone between them, while the sense oscillator has one resonance, which is deliberately placed in the flat region between the two drive resonances. For angular rate detection, the device is operated in the flat zone at the sense resonance frequency at which the device is less susceptible to frequency variations due to both environmental variation and fabrication imperfections and hence is said to be operating in robust mode. The steady-state response and discrimination for angular rate and acceleration sensing have been devised using analytical modeling. The fabrication process is optimized to realize a gyro/accelerometer that has a 9-μm-thick nickel structural layer and 4-μm capacitive gaps. The overall miniature device size is 2.0 mm×1.9 mm. The experimental frequency response of the fabricated devices shows drive-mode resonances at 2.85 and 4.96 kHz and sense resonance at 3.85 kHz compared to the respective design values of drive-mode resonance frequencies 2.97 and 4.81 kHz and sense resonance frequency of 4 kHz. To demonstrate the dual-purpose capability of the device, acceleration characterization has been carried out and presented. The fabricated sensor is packaged in a ceramic package and interfaced with a MS3110 differential capacitive read out IC to characterize the acceleration response of the sensor, using an out-of-plane shaker. The bandwidth for

  11. Characterization and Modeling of a Control Moment Gyroscope

    Science.gov (United States)

    2015-03-26

    Characterization and Modeling of a Control Moment Gyroscope THESIS 2d Lt, Dylan Penn, B.S. AFIT-ENY-MS-15-M-235 DEPARTMENT OF THE AIR FORCE AIR...copyright protection in the United States. AFIT-ENY-MS-15-M-235 CHARACTERIZATION AND MODELING OF A CONTROL MOMENT GYROSCOPE THESIS Presented to the...ENY-MS-15-M-235 CHARACTERIZATION AND MODELING OF A CONTROL MOMENT GYROSCOPE THESIS 2d Lt, Dylan Penn, B.S., B.S. Mechanical Engineering Committee

  12. GPS-Aided Gyroscope-Free Inertial Navigation Systems

    OpenAIRE

    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-...

  13. System Dynamics and Adaptive Control for MEMS Gyroscope Sensor

    Directory of Open Access Journals (Sweden)

    Juntao Fei

    2010-12-01

    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.

  14. A superconducting gyroscope to test Einstein's general theory of relativity

    Science.gov (United States)

    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.

  15. Theoretical and experimental study of the transport of granular materials by inclined vibratory conveyors

    NARCIS (Netherlands)

    Sloot, E.M.; Sloot, E.M.; Kruyt, Nicolaas P.

    1996-01-01

    A theoretical and experimental study was made of the conveying speed with which granular materials are transported by vibratory conveyors. The basic assumption made is that the layer of granular material can be considered as a point mass. The theory incorporates rest, slide, and flight phases of the

  16. Considerations Concerning the Dynamics of Vibratory Mills Used in Powders’ Mechanical Milling Process

    Directory of Open Access Journals (Sweden)

    Radu Panaitescu-Liess

    2010-01-01

    Full Text Available Dynamic mechanical milling process in a powder mill was studied by analyzing the vibratory effects of vibration and shock phenomena on the material microstructure ground. During the milling process, there were noticed both distinct modes of ball motion: the one generated by the periodic vibration and the one produced by chaotic vibration.

  17. Comparison of Axial Capacity of Vibratory-Driven Piles to Impact-Driven Piles.

    Science.gov (United States)

    1987-09-01

    vibratory-driven process results in less compacatiori at the pile tip, thus lowering the tip capacity. Hunter and Davisson (1969), in their...Loading Tests," US Army Engineer District, Little Rock, Ark. Hunter, A. A., and Davisson , M. T. (1969). "Measurement of Pile Load Transfer," Performance

  18. Effects of vibratory pile driver noise on echolocation and vigilance in bottlenose dolphins (Tursiops truncatus).

    Science.gov (United States)

    Branstetter, Brian K; Bowman, Victoria F; Houser, Dorian S; Tormey, Megan; Banks, Patchouly; Finneran, James J; Jenkins, Keith

    2018-01-01

    Vibratory pile drivers, used for marine construction, can produce sustained, high sound pressure levels (SPLs) in areas that overlap with dolphin habitats. Dolphins rely on echolocation for navigation, detecting predators and prey, and to coordinate group behavior. This study examined the effects of vibratory pile driver noise on dolphin sustained target detection capabilities through echolocation. Five dolphins were required to scan their enclosure and indicate the occurrences of phantom echoes during five different source levels of vibratory pile driver playback sound (no-playback control, 110, 120, 130, and 140 dB re 1 μPa). Three of the dolphins demonstrated a significant decrease in target detection performance at 140 dB playback level that was associated with an almost complete secession of echolocation activity. The performance of two dolphins was not affected. All dolphins rapidly returned to baseline levels of target detection performance by their second replication. However, an increased number of clicks was produced at the highest playback SPL. The data suggest that the decrease in vigilant behavior was due to the vibratory pile driver noise distracting the dolphins and decreasing their motivation to perform the task.

  19. ANALYSIS OF VIBRATORY PROTECTION SYSTEM VIBRATION DURING HARMONIC AND POLYHARMONIC EXCITATIONS

    Directory of Open Access Journals (Sweden)

    T. N. Mikulik

    2011-01-01

    Full Text Available The paper considers a mathematical model of local «driver-seat» system and an algorithm for vibratory loading formation at external actions. Results of the investigations on the system vibration according to minimum vibration acceleration depending on transfer force factor acting on the seat and a vibration isolation factor are presented in the paper.

  20. Wave radiation from vibratory and impact pile driving in a layered acousto-elastic medium

    NARCIS (Netherlands)

    Tsouvalas, A.; Metrikine, A.

    2014-01-01

    A steel monopile is the most common foundation type of a wind turbine installed offshore and is driven into place with the help of vibratory or impact hammers. Underwater noise generated during the installation of steel monopiles has recently received considerable attention from international

  1. Assessment of Penile Vibratory Stimulation as a Management Strategy in Men with Secondary Retarded Orgasm

    Science.gov (United States)

    Nelson, Christian J.; Ahmed, Absaar; Valenzuela, Rolando; Parker, Marilyn; Mulhall, John P.

    2016-01-01

    OBJECTIVES To evaluate the effectiveness of penile vibratory stimulation for the management of retarded orgasm. Retarded orgasm, a condition characterized by difficulty achieving orgasm and ejaculation, is one of the most recalcitrant of the male sexual dysfunctions. Currently, no evidence-based treatments have been proven to ameliorate this condition. METHODS Men who had a complete inability to achieve an orgasm during sexual relations in the previous 3 months were instructed in the use of penile vibratory stimulation. The men’s responses were measured by self-report of orgasm function and using the orgasm and satisfaction domains of the International Index of Erectile Function. The responses were assessed at baseline (admission into the study) and at 3 and 6 months. RESULTS A total of 36 men met the inclusion criteria, and 72% reported the restoration of orgasm. These responders reported that orgasm during sexual relations occurred 62% of the time. A statistically and clinically significant increase occurred in the orgasm and satisfaction domains of the International Index of Erectile Function between the baseline visit and the 3-month follow-up visit. These gains were sustained at 6 months. CONCLUSIONS Penile vibratory stimulation is an effective treatment for retarded orgasm. Penile vibratory stimulation should be integrated into current cognitive-behavioral sex therapy techniques to achieve maximal effectiveness and satisfaction. PMID:17382163

  2. Using detrended fluctuation analysis (DFA) to analyze whether vibratory insoles enhance balance stability for elderly fallers.

    Science.gov (United States)

    Wang, Chien-Chih; Yang, Wen-Hung

    2012-01-01

    Falls are a common and devastating problem among elderly people. In a previous study, vibratory insoles were developed to improve postural stability for elderly fallers. To verify the effects of vibratory insoles, a two-stage experiment was conducted to collect center of pressure (COP) signals from 26 elderly fallers and 16 healthy young subjects while standing still. The DFA is used to analyze the behavior of different time-series data obtained from the trajectory of COP. Postural stability was compared by the DFA scaling exponent between a control condition (before using vibratory insoles) and a vibration condition (after using vibratory insoles). For elderly fallers, DFA scaling exponents 95% confidence interval were [1.434, 1.547] and [1.329, 1.451] under control and vibration conditions in the anteroposterior (AP) direction, respectively. The experimental results revealed that temporary stimuli of appropriate amplitude produced by vibration insoles enhanced postural stability in elderly fallers and was more obvious in the AP direction. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  3. Ring laser gyroscope. Ringlaser-Gyroskop

    Energy Technology Data Exchange (ETDEWEB)

    Hutchings, T.

    1984-12-06

    A single laser gyroscope with two laser beams in opposite directions is provided with mirrors at three or four points of reflection, which are mechanically set into vibration. Each mirror is fixed so that it can be moved due to the expansion and contraction of stacks of piezo-electric elements assigned to each mirror. The mirrors are caused to vibrate or oscillate with the same frequency and phase to the outside and inside, so that the spacing for the laser hollow space is kept to a fixed number of wavelengths, but the laser beam is moved backwards and forwards over the surface of the mirrors. This technique avoids the undesirable phenomenon of synchronization at low speeds of rotation, without requiring special optical or magnetic arrangements in the path of the laser beam. (orig.).

  4. Control of Vibratory Energy Harvesters in the Presence of Nonlinearities and Power-Flow Constraints

    Science.gov (United States)

    Cassidy, Ian L.

    Over the past decade, a significant amount of research activity has been devoted to developing electromechanical systems that can convert ambient mechanical vibrations into usable electric power. Such systems, referred to as vibratory energy harvesters, have a number of useful of applications, ranging in scale from self-powered wireless sensors for structural health monitoring in bridges and buildings to energy harvesting from ocean waves. One of the most challenging aspects of this technology concerns the efficient extraction and transmission of power from transducer to storage. Maximizing the rate of power extraction from vibratory energy harvesters is further complicated by the stochastic nature of the disturbance. The primary purpose of this dissertation is to develop feedback control algorithms which optimize the average power generated from stochastically-excited vibratory energy harvesters. This dissertation will illustrate the performance of various controllers using two vibratory energy harvesting systems: an electromagnetic transducer embedded within a flexible structure, and a piezoelectric bimorph cantilever beam. Compared with piezoelectric systems, large-scale electromagnetic systems have received much less attention in the literature despite their ability to generate power at the watt--kilowatt scale. Motivated by this observation, the first part of this dissertation focuses on developing an experimentally validated predictive model of an actively controlled electromagnetic transducer. Following this experimental analysis, linear-quadratic-Gaussian control theory is used to compute unconstrained state feedback controllers for two ideal vibratory energy harvesting systems. This theory is then augmented to account for competing objectives, nonlinearities in the harvester dynamics, and non-quadratic transmission loss models in the electronics. In many vibratory energy harvesting applications, employing a bi-directional power electronic drive to actively

  5. Resonant microsphere gyroscope based on a double Faraday rotator system.

    Science.gov (United States)

    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.

  6. Miniature, Variable-Speed Control Moment Gyroscope Project

    Data.gov (United States)

    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...

  7. Dynamics of an all-optical atomic spin gyroscope.

    Science.gov (United States)

    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.

  8. Gyroscope pivot bearing dimension and surface defect detection

    National Research Council Canada - National Science Library

    Ge, Wenqian; Zhao, Huijie; Li, Xudong

    2011-01-01

    ... 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...

  9. Gyroscope test of gravitation: An analysis of the important perturbations

    Science.gov (United States)

    Oconnell, R. F.

    1971-01-01

    Two perturbations, the earth's quadrupole moment and the earth's revolution around the sun, are discussed. Schiff's proposed gyroscope test of gravitation is analyzed, along with the capability of deciphering each separate contribution to the angular velocity of spin precession.

  10. Non-driven micromechanical gyroscopes and their applications

    CERN Document Server

    Zhang, Fuxue; Wang, Guosheng

    2018-01-01

    This book comprehensively and systematically introduces readers to the theories, structures, performance and applications of non-driven mechanical and non-driven micromechanical gyroscopes. The book is divided into three parts, the first of which mainly addresses mathematic models, precision, performance and operating error in non-driven mechanical gyroscopes. The second part focuses on the operating theory, error, phase shift and performance experiments involving non-driven micromechanical gyroscopes in rotating flight carriers, while the third part shares insights into the application of non-driven micromechanical gyroscopes in control systems for rotating flight carriers. The book offers a unique resource for all researchers and engineers who are interested in the use of inertial devices and automatic control systems for rotating flight carriers.  It can also serve as a reference book for undergraduates, graduates and instructors in related fields at colleges and universities.

  11. Ring-laser gyroscope system using dispersive element(s)

    Science.gov (United States)

    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.

  12. Stellar Gyroscope for Determining Attitude of a Spacecraft

    Science.gov (United States)

    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.

  13. Reproductive Biology, Mating Behavior, and Vibratory Communication of the Brown-Winged Stink Bug, Edessa meditabunda (Fabr. (Heteroptera: Pentatomidae

    Directory of Open Access Journals (Sweden)

    Cleonor Cavalcante A. Silva

    2012-01-01

    Full Text Available We describe different aspects of the reproductive biology, mating behavior, and vibratory communication of the pentatomid Edessa meditabunda (Fabr.. This species shows lower copulation frequency and reproductive potential with longer sexual maturation period compared to other species of pentatomids. Females with multiple mating show increased fecundity when compared with single-mated females and both increased fecundity and reduced longevity when compared with virgin females. Courtship and mating behavior and vibratory signals are typical and similar to what was observed in other species of pentatomids, except that males started the courtship. These results constitute the first paper on biology, behavior, and vibratory communication among species of the subfamily Edessinae.

  14. Spin gyroscope trawlers: profitability of renewing the consumer fleet with vessels equipped with independent spin gyroscope seine and trawl equipment

    National Research Council Canada - National Science Library

    Jorgensen, H.P

    1986-01-01

    The purpose of this report is to throw some light on the profitability of investing in new construction of the so-called spin gyroscope trawler, that is, a vessel which, from the outset, is equipped...

  15. Optimum Tuning of a Gyroscopic Vibration Absorber Using Coupled Gyroscopes for Vibration Control of a Vertical Cantilever Beam

    Directory of Open Access Journals (Sweden)

    F. Ünker

    2016-01-01

    Full Text Available This paper deals with the investigation of optimum values of the stiffness and damping which connect two gyroscopic systems formed by two rotors mounted in gimbal assuming negligible masses for the spring, damper, and gimbal support. These coupled gyroscopes use two gyroscopic flywheels, spinning in opposing directions to have reverse precessions to eliminate the forces due to the torque existing in the torsional spring and the damper between gyroscopes. The system is mounted on a vertical cantilever with the purpose of studying the horizontal and vertical vibrations. The equation of motion of the compound system (gyro-beam system is introduced and solved to find the response measured on the primary system. This is fundamental to design, in some way, the dynamic absorber or neutralizer. On the other hand, the effect of the angular velocities of the gyroscopes are studied, and it is shown that the angular velocity (spin velocity of a gyroscope has a significant effect on the behavior of the dynamic motion. Correctness of the analytical results is verified by numerical simulations. The comparison with the results from the derivation of the corresponding frequency equations shows that the optimized stiffness and damping values are very accurate.

  16. IMPACT OF VIBRATORY AND ROTATIONAL SHOT PEENING ONTO SELECTED PROPERTIES OF TITANIUM ALLOY SURFACE LAYER

    Directory of Open Access Journals (Sweden)

    Kazimierz Zaleski

    2014-06-01

    Full Text Available This study presents the results of tests on impact of vibratory and rotational shot peening of the Ti6A12Mo2Cr titanium alloy onto the processed object surface roughness and surface layer microhardness. The external surfaces of ring-shaped samples were shot peened. The preceding process consisted of turning with a cubic boron nitride blade knife. Steel beads, having a diameter of 6 mm, were used as a processing medium. The variable parameters of shot peening were vibrator amplitude and shot peening time. The range of recommended technological parameters for vibratory and rotational shot peening was determined. As a result of shot peening, the surface roughness could be reduced by approximately 4 times and the surface layer could be hardened to the depth of approximately 0.4 mm.

  17. Vibratory-compacted (vipac/sphere-pac) nuclear fuels - a comparison with pelletized nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    Chidester, K.; Rubin, J. [Los Alamos National Lab., NM (United States); Thompson, M

    2001-07-01

    In order to achieve the packing densities required for nuclear fuel stability, economy and performance, the fuel material must be densified. This has traditionally been performed by high-temperature sintering. (At one time, fuel densification was investigated using cold/hot swaging. However, this fabrication method has become uncommon.) Alternatively, fuel can be densified by vibratory compaction (VIPAC). During the late 1950's and into the 1970's, in the U.S., vibratory compaction fuel was fabricated and test irradiated to evaluate its applicability compared to the more traditional pelletized fuel for nuclear reactors. These activities were primarily focused on light water reactors (LWR) but some work was performed for fast reactors. This paper attempts to summarize these evaluations and proposes to reconsider VIPAC fuel for future use. (author)

  18. Vibratory sensory testing in acute compartment syndromes: a clinical and experimental study.

    Science.gov (United States)

    Phillips, J H; Mackinnon, S E; Beatty, S E; Dellon, A L; O'Brien, J P

    1987-05-01

    Invasive and noninvasive diagnostic testing was correlated in 11 patients with acute compartmental syndromes of the forearm. The excellent correlation between diminished perception of vibration and increasing compartmental pressure suggested that 256 cycle per second (cps) vibratory stimuli may be useful clinically in determining the appropriate time for surgical intervention in the acute compartmental syndrome. In 12 adult male volunteers, elevated compartment pressures were created in the anterior tibial compartment of the leg. A decrease in perception to 256 cycle per second (cps) vibratory stimulus was the earliest sensory abnormality to occur with elevated tissue compartment pressures. Analysis of variance showed significantly that 256-cps vibration was the most reliable and earliest sensory modality to change at pressures of 35 to 40 mmHg. These clinical and experimental findings support the use of the 256-cps tuning fork as a noninvasive diagnostic test in the evaluation of the patient with suspected acute compartment syndrome.

  19. Modeling and optimizing of the random atomic spin gyroscope drift based on the atomic spin gyroscope.

    Science.gov (United States)

    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.

  20. Modeling and optimizing of the random atomic spin gyroscope drift based on the atomic spin gyroscope

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Nuclear-Spin Gyroscope Based on an Atomic Co-Magnetometer

    Science.gov (United States)

    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.

  2. Theoretical and experimental study of the transport of granular materials by inclined vibratory conveyors

    OpenAIRE

    Sloot, E.M.; Kruyt, Nicolaas P.

    1996-01-01

    A theoretical and experimental study was made of the conveying speed with which granular materials are transported by vibratory conveyors. The basic assumption made is that the layer of granular material can be considered as a point mass. The theory incorporates rest, slide, and flight phases of the material. Although the emphasis of this study is on the effect of the inclination (and declination) of the conveyor on the conveying speed, the effects of throw number, friction coefficient and vi...

  3. Simulation of an Electromechanical Spin Motor System of a Control Moment Gyroscope

    Science.gov (United States)

    Inampudi, Ravi; Gordeuk, John

    2016-01-01

    A two-phase brushless DC motor (BDCM) with pulse-width modulated (PWM) voltage drive is simulated to control the flywheel speed of a control moment gyroscope (CMG). An overview of a double-gimballed control moment gyroscope (DGCMG) assembly is presented along with the CMG torque effects on the spacecraft. The operating principles of a two-phase brushless DC motor are presented and the system's electro-mechanical equations of motion are developed for the root-mean-square (RMS) currents and wheel speed. It is shown that the system is an extremely "stiff" set of first-order equations for which an implicit Euler integrator is required for a stable solution. An adaptive proportional voltage controller is presented which adjusts the PWM voltages depending on several control modes for speed, current, and torque. The simulation results illustrate the interaction between the electrical system and the load dynamics and how these influence the overall performance of the system. As will be shown, the CMG spin motor model can directly provide electrical power use and thermal power output to spacecraft subsystems for effective (average) calculations of CMG power consumption.

  4. Modeling and Implementation of Multi-Position Non-Continuous Rotation Gyroscope North Finder.

    Science.gov (United States)

    Luo, Jun; Wang, Zhiqian; Shen, Chengwu; Kuijper, Arjan; Wen, Zhuoman; Liu, Shaojin

    2016-09-20

    Even when the Global Positioning System (GPS) signal is blocked, a rate gyroscope (gyro) north finder is capable of providing the required azimuth reference information to a certain extent. In order to measure the azimuth between the observer and the north direction very accurately, we propose a multi-position non-continuous rotation gyro north finding scheme. Our new generalized mathematical model analyzes the elements that affect the azimuth measurement precision and can thus provide high precision azimuth reference information. Based on the gyro's principle of detecting a projection of the earth rotation rate on its sensitive axis and the proposed north finding scheme, we are able to deduct an accurate mathematical model of the gyro outputs against azimuth with the gyro and shaft misalignments. Combining the gyro outputs model and the theory of propagation of uncertainty, some approaches to optimize north finding are provided, including reducing the gyro bias error, constraining the gyro random error, increasing the number of rotation points, improving rotation angle measurement precision, decreasing the gyro and the shaft misalignment angles. According them, a north finder setup is built and the azimuth uncertainty of 18" is obtained. This paper provides systematic theory for analyzing the details of the gyro north finder scheme from simulation to implementation. The proposed theory can guide both applied researchers in academia and advanced practitioners in industry for designing high precision robust north finder based on different types of rate gyroscopes.

  5. Microelectromechanical System (MEMS) Gyroscope Noise Analysis and Scale Factor Characterization over Temperature Variation

    Science.gov (United States)

    2016-07-01

    ARL-TR-7718 ● JULY 2016 US Army Research Laboratory Microelectromechanical System (MEMS) Gyroscope Noise Analysis and Scale...JULY 2016 US Army Research Laboratory Microelectromechanical System (MEMS) Gyroscope Noise Analysis and Scale Factor Characterization...System (MEMS) Gyroscope Noise Analysis and Scale Factor Characterization over Temperature Variation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  6. A comparative analysis of modal motions for the gyroscopic and non-gyroscopic two degree-of-freedom conservative systems

    Science.gov (United States)

    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.

  7. Hybrid fiber resonator employing LRSPP waveguide coupler for gyroscope.

    Science.gov (United States)

    Qian, Guang; Fu, Xing-Chang; Zhang, Li-Jiang; Tang, Jie; Liu, Yi-Ran; Zhang, Xiao-Yang; Zhang, Tong

    2017-01-24

    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.

  8. Light-shift measurement and suppression in atomic spin gyroscope.

    Science.gov (United States)

    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.

  9. A micro-machined gyroscope for rotating aircraft.

    Science.gov (United States)

    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.

  10. Thermal and Quantum Mechanical Noise of a Superfluid Gyroscope

    Science.gov (United States)

    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.

  11. A Novel Control System Design for Vibrational MEMS Gyroscopes

    Directory of Open Access Journals (Sweden)

    Qing Zheng

    2007-04-01

    Full Text Available There are two major control problems associated with vibrational MEMS gyroscopes: to control two vibrating axes (or modes of the gyroscope, and to estimate a time-varying rotation rate. This paper demonstrates how a novel active disturbance rejection control addresses these problems in the presence of the mismatch of natural frequencies between two axes, mechanical-thermal noises, Quadrature errors, and parameter variations. A demodulation approach based on the estimated dynamics of the system by an extended state observer is used to estimate the rotation rate. The simulation results on a Z-axis MEMS gyroscope show that the controller is very effective by driving the output of the drive axis to a desired trajectory, forcing the vibration of the sense axis to zero for a force-to-rebalance operation and precisely estimating the rotation rate.

  12. A Micro-Machined Gyroscope for Rotating Aircraft

    Directory of Open Access Journals (Sweden)

    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.

  13. Miniature, Variable-Speed Control Moment Gyroscope

    Science.gov (United States)

    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.

  14. A New MEMS Gyroscope Used for Single-Channel Damping.

    Science.gov (United States)

    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.

  15. Full Stokes polarimeter for characterization of fiber optic gyroscope coils.

    Science.gov (United States)

    Lompado, Arthur; Reinhardt, John C; Heaton, L Chris; Williams, Jeff L; Ruffin, Paul B

    2009-05-11

    We describe the design, construction, calibration, and validation of a Stokes vector polarimeter for investigating the polarization characteristics of fiber optic gyroscope coils. The device measures the complete Stokes vector, and reports conventional polarization properties including the Degree of Polarization (DoP), the orientation and Degree of Linear Polarization (DoLP), and the handedness and Degree of Circular Polarization (DoCP). The sensor operates at 1550 nm and employs a division of aperture optical architecture to acquire full Stokes vectors at 8 kHz while calculating polarization properties at a rate of 200 Hz. Preliminary measurements performed on both traditionally and unconventionally wound gyroscope coils are also presented.

  16. Studying rotational dynamics with a smartphone—accelerometer versus gyroscope

    Science.gov (United States)

    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.

  17. Towards a biomimetic gyroscope inspired by the fly's haltere using microelectromechanical systems technology.

    Science.gov (United States)

    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. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  18. Nonlinear vibration analysis of axially moving strings based on gyroscopic modes decoupling

    Science.gov (United States)

    Yang, Xiao-Dong; Wu, Hang; Qian, Ying-Jing; Zhang, Wei; Lim, C. W.

    2017-04-01

    A novel idea that applies the multiple scale analysis to a discretized decoupled system of gyroscopic continua is introduced and an axial moving string is treated as an example. First, the invariant manifold method is applied to the discretized ordinary differential equations of the axially moving string. Complex gyroscopic mode functions that agree well with true analytical results are obtained. The gyroscopic modes are subsequently used for the discretized ordinary differential equations with gyroscopic and nonlinear coupling terms that yield a gyroscopically decoupled system. Further the method of multiple scales is used to obtain the equations at a slow scale. This novel procedure is compared to solutions obtained by directly applying the classical multiple scale analysis to the gyroscopically coupled system without decoupling. The modal decoupled system analysis yields better frequency with comparing to the classic method. The proposed methodology provides a novel alternative for nonlinear dynamic analysis of gyroscopic continua.

  19. Vibratory stimulation and rectal probe electroejaculation as therapy for patients with spinal cord injury: semen parameters and pregnancy rates.

    Science.gov (United States)

    Nehra, A; Werner, M A; Bastuba, M; Title, C; Oates, R D

    1996-02-01

    The conception rate of patients with spinal cord injuries following penile vibratory stimulation and rectal probe electroejaculation in conjunction with self-insemination, intrauterine insemination or assisted reproductive technique is poorly documented. We reviewed our success rates with penile vibratory stimulation and rectal probe electroejaculation, and the pregnancy rates achieved with self-insemination, intrauterine insemination and assisted reproductive techniques. A total of 78 consecutive patients with spinal cord injuries had a complete neurological examination and was treated initially with penile vibratory stimulation. If unsuccessful, rectal probe electroejaculation was performed to obtain an ejaculate. The ejaculate was then used with self-insemination, intrauterine insemination or assisted reproductive techniques and pregnancies were monitored. Vibratory stimulation was successful in 20 of 37 patients (54%) with a cervical lesion, 14 of 26 (54%) with a lesion at or above T10 and none of 15 when the lesion was below T10. All patients except 2 who elected followup rectal probe electroejaculation had antegrade or retrograde ejaculate. Six patients (7.7%) with extremely poor semen quality were not candidates for assisted fertilization. Of 27 couples who attempted conception 17 were successful (5 self-insemination, 5 intrauterine insemination and 7 assisted reproductive techniques). Penile vibratory stimulation should be used as first line therapy in patients with lesions above T10 while rectal probe electroejaculation should be considered as a second option. Motivated patients can achieve success with self-insemination, intrauterine insemination and assisted reproductive techniques.

  20. Understanding Organizational Culture and Communication through a Gyroscope Metaphor

    Science.gov (United States)

    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…

  1. Indefinite damping in mechanical systems and gyroscopic stabilization

    DEFF Research Database (Denmark)

    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 dot...

  2. Noise Reduction for a MEMS-Gyroscope-Based Head Mouse.

    Science.gov (United States)

    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.

  3. Comments on Stability Properties of Conservative Gyroscopic Systems

    DEFF Research Database (Denmark)

    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...

  4. Design and analysis of a gyroscopically controlled micro air vehicle

    Science.gov (United States)

    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.

  5. Identification of the 3D Vibratory Motion of a Rigid Body by Accelerometer Measurements

    Directory of Open Access Journals (Sweden)

    Francesca Di Puccio

    2004-01-01

    Full Text Available The identification of the motion of a rigid body by means of linear accelerometers is a problem already investigated by many researchers, but still debated. The optimisation of the number and placement of accelerometers is also another important aspect of the problem. In this study, an experimental procedure is proposed and applied to identify the rigid-body vibratory motion of the steering wheel of a sporting car, by means of six linear accelerometers. Some numerical simulations for investigating possible errors are also presented.

  6. Fundamental understanding, prediction and validation of rotor vibratory loads in steady-level flight

    Science.gov (United States)

    Datta, Anubhav

    This work isolates the physics of aerodynamics and structural dynamics from the helicopter rotor aeromechanics problem, investigates them separately, identifies the prediction deficiencies in each, improves upon them, and couples them back together. The objective is to develop a comprehensive analysis capability for accurate and consistent prediction of rotor vibratory loads in steady level flight. The rotor vibratory loads are the dominant source of helicopter vibration. There are two critical vibration regimes for helicopters in steady level flight: (1) low speed transition and (2) high speed forward flight. The mechanism of rotor vibration at low speed transition is well understood---inter-twinning of blade tip vortices below the rotor disk. The mechanism of rotor vibration at high speed is not clear. The focus in this research is on high speed flight. The goal is to understand the key mechanisms involved and accurately model them. Measured lift, chord force, pitching moment and damper force from the UH-60A Flight Test Program are used to predict, validate and refine the rotor structural dynamics. The prediction errors originate entirely from structural modeling. Once validated, the resultant blade deformations are used to predict and validate aerodynamics. Air loads are calculated using a table look up based unsteady lifting-line model and compared with predictions from a 3-dimensional unsteady CFD model. Both Navier-Stokes and Euler predictions are studied. (Abstract shortened by UMI.) The 3D Navier-Stokes CFD analysis is then consistently coupled with a rotor comprehensive analysis to improve prediction of rotor vibratory loads at high speed. The CFD-comprehensive code coupling is achieved using a loose coupling methodology. The CFD analysis significantly improves section pitching moment prediction near the blade tip, because it captures the steady and unsteady 3D transonic effects. Accurate pitching moments drive elastic twist deformations which together

  7. Cavitation Erosion Tests Performed by Indirect Vibratory Method on Stainless Steel Welded Samples with Hardened Surface

    Directory of Open Access Journals (Sweden)

    Marian-Dumitru Nedeloni

    2012-09-01

    Full Text Available The paper presents the results of cavitation erosion tests performed on two types of samples. The materials of the samples are frequently used for manufacturing and repairs of the hydro turbines components submitted to cavitation. The first sample was made by welding of an austenitic stainless steel on austenito-feritic base material. The second sample was made similarly with the first but with a martensitic base material. After the welding processes, on both samples was applied a hardening treatment by surface peening. The cavitation erosion tests were performed on vibratory equipment using the indirect method with stationary specimen. The results show a good cavitation erosion resistance on both samples.

  8. Optimization of process parameters during vibratory welding technique using Taguchi's analysis

    OpenAIRE

    Singh, Pravin Kumar; Patel, D.; Prasad,S.B.

    2016-01-01

    With an aim to improve the mechanical properties of a weld joint, a new concept of vibratory setup has been designed which is capable to stir the molten weld pool before it solidifies during shielded metal arc welding (SMAW) operation. Mechanical vibration having resonance frequency of 300 Hz and amplitude of 0.5 mm was transferred to the molten weld pool of 6 mm thick mild steel butt-welded joints during the welding operation. The experimental work was conducted at various ranges of frequenc...

  9. Identification of elasticity modulus by vibratory analysis (Application to a natural composite: Aleppo pine wood

    Directory of Open Access Journals (Sweden)

    DAOUI Abdelhakim

    2018-01-01

    Full Text Available In this paper, we present a method for the determination of the elasticity modulus in the vibratory domain of materials. This approach is based on research and interpretation of the spectrum of natural frequencies resulting from natural vibrations based on the theory of elastic beams. The tests consist of classical tests of longitudinal vibrations of natural composite beams (Aleppo pine wood, long enough to observe some natural frequencies. This identification method showed a good correlation between the theoretical and experimental values, notably the evaluation of the modal parameter for the case of the resonant frequencies and the identification of the modulus of elasticity of the materials used.

  10. Penile vibratory stimulation and electroejaculation in the treatment of ejaculatory dysfunction.

    Science.gov (United States)

    Sønksen, Jens; Ohl, Dana A

    2002-12-01

    The purpose of this review is to present the current understanding of penile vibratory stimulation (PVS) and electroejaculation (EEJ) procedures and its clinical use in men with ejaculatory dysfunction. Unfortunately, the record of treating such individuals has been quite poor, but within recent years development and refinement of PVS and EEJ in men with spinal cord injury (SCI) has significantly enhanced the prospects for treatment of ejaculatory dysfunction. The majority of spinal cord injured men are not able to produce antegrade ejaculation by masturbation or sexual stimulation. However, approximately 80% of all spinal cord injured men with an intact ejaculatory reflex arc (above T10) can obtain antegrade ejaculation with PVS. Electroejaculation may be successful in obtaining ejaculate from men with all types of SCI, including men who do not have major components of the ejaculatory reflex arc. Because vibratory stimulation is very simple in use, non-invasive, it does not require anaesthesia and is preferred by the patients when compared with EEJ, PVS is recommended to be the first choice of treatment in spinal cord injured men. Furthermore, EEJ has been successfully used to induce ejaculation in men with multiple sclerosis and diabetic neuropathy. Any other conditions which affect the ejaculatory mechanism of the central and/or peripheral nervous system including surgical nerve injury may be treated successfully with EEJ. Finally, for sperm retrieval and sperm cryopreservation before intensive anticancer therapy in pubertal boys, PVS and EEJ have been successfully performed in patients who failed to obtain ejaculation by masturbation. Nearly all data concerning semen characteristics in men with ejaculatory dysfuntion originate from spinal cord injured men. Semen analyses demonstrate low sperm motility rates in the majority of spinal cord injured men. The data give evidence of a decline in spermatogenesis and motility of ejaculated spermatozoa shortly after (few

  11. Comparison of energy costs for different control laws of a vibratory robot

    Science.gov (United States)

    Golitsyna, Maria

    2017-01-01

    In the study there are introduced several control methods that maximize average velocity of the vibratory robot subject to several constraints. The robot is presented by a rigid box with a pendulum inside it. It can move forwards and backwards and there is a Coulomb friction between the box and the surface. In the paper it is not only shown the difference and advantages of proposed control laws but there is also done a comparison between efforts done by the motor that provides rotation of the pendulum for different control methods.

  12. Dynamic Performance Comparison of Two Kalman Filters for Rate Signal Direct Modeling and Differencing Modeling for Combining a MEMS Gyroscope Array to Improve Accuracy

    Directory of Open Access Journals (Sweden)

    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.

  13. Dynamic Performance Comparison of Two Kalman Filters for Rate Signal Direct Modeling and Differencing Modeling for Combining a MEMS Gyroscope Array to Improve Accuracy.

    Science.gov (United States)

    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.

  14. The action principle for generalized fluid motion including gyroviscosity

    Energy Technology Data Exchange (ETDEWEB)

    Lingam, M., E-mail: manasvi@physics.utexas.edu; Morrison, P.J., E-mail: morrison@physics.utexas.edu

    2014-11-07

    Highlights: • Method for constructing action principles for a diverse class of fluids with gyroscopic momentum transport is described. • General criteria for the conservation of momentum and angular momentum via Noether's theorem are obtained. • Fluids with intrinsic angular momentum are built as an illustration of the method. - Abstract: A general set of fluid equations that allow for energy-conserving momentum transport by gyroscopic motion of fluid elements is obtained. The equations are produced by a class of action principles that yield a large subset of the known fluid and magnetofluid models, including gyroviscosity. Analysis of the action principle yields broad, model-independent results regarding the conservation laws of energy and linear and angular momenta. The formalism is illustrated by studying fluid models with intrinsic angular momentum that may appear in the contexts of condensed matter, biological, and other areas of physics.

  15. Optimization of process parameters during vibratory welding technique using Taguchi's analysis

    Directory of Open Access Journals (Sweden)

    Pravin Kumar Singh

    2016-09-01

    Full Text Available With an aim to improve the mechanical properties of a weld joint, a new concept of vibratory setup has been designed which is capable to stir the molten weld pool before it solidifies during shielded metal arc welding (SMAW operation. Mechanical vibration having resonance frequency of 300 Hz and amplitude of 0.5 mm was transferred to the molten weld pool of 6 mm thick mild steel butt-welded joints during the welding operation. The experimental work was conducted at various ranges of frequencies, welding current and welding speed. Taguchi's analysis technique has been applied to optimize the process parameters; the response values for analysis are yield strength and micro-hardness. The test results showed that with the application of the vibratory treatment the values of hardness and tensile properties increased. The auxiliary vibrations induced into the weld pool resulted in increased micro-hardness of the weld metal which indicates the orientation of the crystal and refinement of grains took place. This study shows that vibration applied into the weld pool can be successfully improved the mechanical properties of welded joints. Thus this research attempt provided an alternative welding technique for grain refinement of weldments.

  16. [Penile vibratory stimulation and electroejaculation in the treatment of ejaculatory dysfunction].

    Science.gov (United States)

    Fan, Long-chang; Liu, Ji-hong

    2005-03-01

    The fertility potential of infertile men can be enhanced to a great extent by the application of assisted reproduction techniques such as intrauterine insemination or in-vitro fertilization with or without intracytoplasmic sperm injection, but how to obtain semen from men with ejaculatory dysfunction remains a problem. The development and refinement of penile vibratory stimulation (PVS) and electroejaculation (EEJ) have significantly brightened the prospects for the treatment of ejaculatory dysfunction. Because vibratory stimulation is non-invasive and easy to perform, and needs no anaesthesia, it is preferred by most of the patients to EEJ, and recommended to be the first choice of treatment for ejaculatory dysfunction. Approximately 80% of all ejaculatory dysfunction men with an intact ejaculatory reflex arc (above T10 ) can obtain antegrade ejaculation by PVS. Any condition which affects the ejaculatory mechanism of the central and/or peripheral nervous system including surgical nerve injury may be treated successfully by EEJ. The purpose of this review is to present the current understanding of PVS and EEJ procedures and their clinical use in men with ejaculatory dysfunction.

  17. Spontaneous emission noise in long-range surface plasmon polariton waveguide based optical gyroscope.

    Science.gov (United States)

    Wang, Yang-Yang; Zhang, Tong

    2014-09-19

    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.

  18. A Fully Symmetric and Completely Decoupled MEMS-SOI Gyroscope

    Directory of Open Access Journals (Sweden)

    Abdelhameed SHARAF

    2011-04-01

    Full Text Available This paper introduces a novel MEMS gyroscope that is capable of exciting the drive mode differentially. The structure also decouples the drive and sense modes via an intermediate mass and decoupling beams. Both drive and sense modes are fully differential enabling control over the zero-rate-output for the former and maximizing output sensitivity using a bridge circuit for the latter. Further, the structure is fully symmetric about the x- and y- axes which results in minimizing the temperature sensitivity problem. Complete analytical analysis based on the equations of motion was performed and verified using two commercially available finite element software packages. Results from both methods are in good agreement. The analysis of the sensor shows an electrical sensitivity of 1.14 (mV/(º/s. The gyroscope was fabricated using single mask and deep reactive ion etching. The measurement of the resonance frequency performed showing a good agreement with the analytical and numerical analysis.

  19. Facial expression classification using EEG and gyroscope signals.

    Science.gov (United States)

    Toth, Jake; Arvaneh, Mahnaz

    2017-07-01

    In this paper muscle and gyroscope signals provided by a low cost EEG headset were used to classify six different facial expressions. Muscle activities generated by facial expressions are seen in EEG data recorded from scalp. Using the already present EEG device to classify facial expressions allows for a new hybrid brain-computer interface (BCI) system without introducing new hardware such as separate electromyography (EMG) electrodes. To classify facial expressions, time domain and frequency domain EEG data with different sampling rates were used as inputs of the classifiers. The experimental results showed that with sampling rates and classification methods optimized for each participant and feature set, high accuracy classification of facial expressions was achieved. Moreover, adding information extracted from a gyroscope embedded into the used EEG headset increased the performance by an average of 9 to 16%.

  20. Robust adaptive control of MEMS triaxial gyroscope using fuzzy compensator.

    Science.gov (United States)

    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.

  1. High resolution capacitance detection circuit for rotor micro-gyroscope

    Directory of Open Access Journals (Sweden)

    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.

  2. Gyroscope and visual fusion solution for digital video stabilization

    Science.gov (United States)

    Wei, Shanshan; He, Zhiqiang; Xie, Wei

    2016-09-01

    A gyroscope and visual fusion solution for digital video stabilization (DVS) is presented. The solution classifies DVS-related motions into three types: the object motion (OM) in the world space, the camera motion in the camera space (CS), and the pixel motion in the image space (IS). The camera rotation is estimated by gyroscope and smoothed in the CS, while the camera translation is compounded with the OM and smoothed together in the IS. The main contributions of this paper lie in two aspects: (1) propose an inertial and visual fusion method to stabilize both rotational and translational jitters and (2) the fusion method is simple and fast in computation and can be suitable for smart terminals. Experimental results show that the proposed solution performs well in video stabilization.

  3. Collision avoidance for multiple Lagrangian dynamical systems with gyroscopic forces

    Directory of Open Access Journals (Sweden)

    Lorenzo Sabattini

    2017-01-01

    Full Text Available This article introduces a novel methodology for dealing with collision avoidance for groups of mobile robots. In particular, full dynamics are considered, since each robot is modeled as a Lagrangian dynamical system moving in a three-dimensional environment. Gyroscopic forces are utilized for defining the collision avoidance control strategy: This kind of forces leads to avoiding collisions, without interfering with the convergence properties of the multi-robot system’s desired control law. Collision avoidance introduces, in fact, a perturbation on the nominal behavior of the system: We define a method for choosing the direction of the gyroscopic force in an optimal manner, in such a way that perturbation is minimized. Collision avoidance and convergence properties are analytically demonstrated, and simulation results are provided for validation purpose.

  4. A Fully Symmetric and Completely Decoupled MEMS-SOI Gyroscope

    OpenAIRE

    Abdelhameed SHARAF; Sherif SEDKY; Mohamed SERRY; Amro ELSHURAFA; Mahmoud ASHOUR; S. E.-D. HABIB

    2011-01-01

    This paper introduces a novel MEMS gyroscope that is capable of exciting the drive mode differentially. The structure also decouples the drive and sense modes via an intermediate mass and decoupling beams. Both drive and sense modes are fully differential enabling control over the zero-rate-output for the former and maximizing output sensitivity using a bridge circuit for the latter. Further, the structure is fully symmetric about the x- and y- axes which results in minimizing the temperature...

  5. OPTIMIZATION OF HEMISPHERICAL RESONATOR GYROSCOPE STANDING WAVE PARAMETERS

    Directory of Open Access Journals (Sweden)

    Olga Sergeevna Khalyutina

    2017-01-01

    Full Text Available Traditionally, the problem of autonomous navigation is solved by dead reckoning navigation flight parameters (NFP of the aircraft (AC. With increasing requirements to accuracy of definition NFP improved the sensors of the prima- ry navigation information: gyroscopes and accelerometers. the gyroscopes of a new type, the so-called solid-state wave gyroscopes (SSVG are currently developed and put into practice. The work deals with the problem of increasing the accu- racy of measurements of angular velocity of the hemispherical resonator gyroscope (HRG. The reduction in the accuracy characteristics of HRG is caused by the presence of defects in the distribution of mass in the volume of its design. The syn- thesis of control system for optimal damping of the distortion parameters of the standing wave due to the influence of the mass defect resonator is adapted. The research challenge was: to examine and analytically offset the impact of the standing wave (amplitude and frequency parameters defect. Research was performed by mathematical modeling in the environment of SolidWorks Simulation for the case when the characteristics of the sensitive element of the HRG met the technological drawings of a particular type of resonator. The method of the inverse dynamics was chosen for synthesis. The research re- sults are presented in graphs the amplitude-frequency characteristics (AFC of the resonator output signal. Simulation was performed for the cases: the perfect distribution of weight; the presence of the mass defect; the presence of the mass defects are shown using the synthesized control action. Evaluating the effectiveness of the proposed control algorithm is deter- mined by the results of the resonator output signal simulation provided the perfect constructive and its performance in the presence of a mass defect in it. It is assumed that the excitation signals are standing waves in the two cases are identical in both amplitude and frequency. In this

  6. Closed-loop fiber optic gyroscope with homodyne detection

    Science.gov (United States)

    Zhu, Yong; Qin, BingKun; Chen, Shufen

    1996-09-01

    Interferometric fiber optic gyroscope (IFOG) has been analyzed with autocontrol theory in this paper. An open-loop IFOG system is not able to restrain the bias drift, but a closed-loop IFOG system can do it very well using negative feedback in order to suppress zero drift. The result of our theoretic analysis and computer simulation indicate that the bias drift of a closed-loop system is smaller than an open- loop one.

  7. The Gyroscope Sensor Test by Using Arduino Platform

    Directory of Open Access Journals (Sweden)

    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.

  8. A real time self-temperature compensation method used for MEMS gyroscopes

    Science.gov (United States)

    Ma, Zishuai; Qiu, Anping; Shi, Qin; Xia, Guoming; Zhao, Yang

    2017-10-01

    This article presents a self-temperature compensation method used for MEMS gyroscopes. Drive frequency of gyroscope is employed as temperature compensation source, so that no external temperature sensor needed. When gyroscope starts to work, the circuit generates heat, providing the temperature input. Meanwhile, only 120 seconds is needed to calculate compensation parameters without pre-calibration. Therefore, the efficiency of experiment and study can be improved by this method.

  9. Practical Considerations on the Multi-layer Mirrors for Superluminal Ring Laser Gyroscopes

    Science.gov (United States)

    Wang, Zhiguo; Yuan, Baolun

    2015-07-01

    We have created a simple model to analyze the restrictions on superluminal ring laser gyroscopes arising from the absorption of coating materials. For a ring laser gyroscope with a cavity length of 15 cm, the scale factor enhancement is nearly impossible due to absorption from the high dispersion mirror. In order to obtain a practical superluminal ring laser gyroscope, the extinction coefficient of coating materials should be less than 1E-10, which is a challenge at present.

  10. Improving ATV’s stability by means of a gyroscopic mechanism

    Directory of Open Access Journals (Sweden)

    Minkovska Iliyana

    2017-01-01

    Full Text Available This paper presents research carried out to improve ATV stability by means of a built-in gyroscopic mechanism. For this purpose, a mathematical model was used. The negative gyroscopic effect of wheel rotation on ATV stability is considered. The theoretical results for ATV motion and the impact of the built-in gyroscopic mechanism on its stability under various conditions are presented.

  11. Multiple hindered rotators in a gyroscope-inspired tribenzylamine hemicryptophane.

    Science.gov (United States)

    Khan, Najat S; Perez-Aguilar, Jose Manuel; Kaufmann, Tara; Hill, P Aru; Taratula, Olena; Lee, One-Sun; Carroll, Patrick J; Saven, Jeffery G; Dmochowski, Ivan J

    2011-03-04

    A gyroscope-inspired tribenzylamine hemicryptophane provides a vehicle for exploring the structure and properties of multiple p-phenylene rotators within one molecule. The hemicryptophane was synthesized in three steps in good overall yield using mild conditions. Three rotator-forming linkers were cyclized to form a rigid cyclotriveratrylene (CTV) stator framework, which was then closed with an amine. The gyroscope-like molecule was characterized by (1)H NMR and (13)C NMR spectroscopy, and the structure was solved by X-ray crystallography. The rigidity of the two-component CTV-trismethylamine stator was investigated by (1)H variable-temperature (VT) NMR experiments and molecular dynamics simulations. These techniques identified gyration of the three p-phenylene rotators on the millisecond time scale at -93 °C, with more dynamic but still hindered motion at room temperature (27 °C). The activation energy for the p-phenylene rotation was determined to be ~10 kcal mol(-1). Due to the propeller arrangement of the p-phenylenes, their rotation is hindered but not strongly correlated. The compact size, simple synthetic route, and molecular motions of this gyroscope-inspired tribenzylamine hemicryptophane make it an attractive starting point for controlling the direction and coupling of rotators within molecular systems.

  12. Modal Damping Ratio and Optimal Elastic Moduli of Human Body Segments for Anthropometric Vibratory Model of Standing Subjects.

    Science.gov (United States)

    Gupta, Manoj; Gupta, T C

    2017-10-01

    The present study aims to accurately estimate inertial, physical, and dynamic parameters of human body vibratory model consistent with physical structure of the human body that also replicates its dynamic response. A 13 degree-of-freedom (DOF) lumped parameter model for standing person subjected to support excitation is established. Model parameters are determined from anthropometric measurements, uniform mass density, elastic modulus of individual body segments, and modal damping ratios. Elastic moduli of ellipsoidal body segments are initially estimated by comparing stiffness of spring elements, calculated from a detailed scheme, and values available in literature for same. These values are further optimized by minimizing difference between theoretically calculated platform-to-head transmissibility ratio (TR) and experimental measurements. Modal damping ratios are estimated from experimental transmissibility response using two dominant peaks in the frequency range of 0-25 Hz. From comparison between dynamic response determined form modal analysis and experimental results, a set of elastic moduli for different segments of human body and a novel scheme to determine modal damping ratios from TR plots, are established. Acceptable match between transmissibility values calculated from the vibratory model and experimental measurements for 50th percentile U.S. male, except at very low frequencies, establishes the human body model developed. Also, reasonable agreement obtained between theoretical response curve and experimental response envelop for average Indian male, affirms the technique used for constructing vibratory model of a standing person. Present work attempts to develop effective technique for constructing subject specific damped vibratory model based on its physical measurements.

  13. An Advanced Micromachined Package for the Quartz Disk Resonant Gyroscope Project

    Data.gov (United States)

    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...

  14. Characterization of vibratory turning in cutting zone using a pneumatic quick-stop device

    Directory of Open Access Journals (Sweden)

    Saeid Amini

    2017-04-01

    Full Text Available Shear angle and sticking length are two crucial parameters in mechanics of metal cutting. These two parameters directly influence machinability factors such as cutting forces. Thus, shear angle and sticking length were investigated in vibratory turning process by using a pneumatic quick-stop device which was designed and fabricated, in this study. After preparation of ultrasonic assisted turning set-up, experimental tests have been carried out on two types of steel: AISI-1060 and AISI 304. Accordingly, the process of chip formation in each particular cutting test was quickly stopped when deformed chip was still in contact with workpiece. As a result, it was revealed that added linear vibration leads the turning operation to be improved by increase of shear angle and decrease of sticking length. Moreover, the effect of ultrasonic vibration on cutting force and chip micro-hardness is evaluated.

  15. Interspectral combination type resonances of nonlinear conservative/nonconservative distributed parameter vibratory systems

    Science.gov (United States)

    Padovan, J.

    1985-06-01

    This paper investigates the properties/formation of combination type resonances of nonlinear conservative/nonconservative distributed parameter vibratory systems subject to external harmonic inputs containing a profusion of frequencies. Overall, this includes the evaluation of simultaneously excited harmonic, sub/superharmonics as well as combination harmonics created by interactions between external and interspectral system frequency branches. Additionally, effort is also given to handling nonconservative characteristics wherein critical damping levels may suppress specific combination harmonics. The foregoing is made possible through the development of a warped and constrained multiple time scales perturbation solution scheme. To illustrate the scheme as well as the nature and form of external and interspectral interaction, a nonlinear nonconservative version of the wave equation which is excited by complex external harmonic fields is given detailed consideration.

  16. Application of vibratory-percussion crusher for disintegration of supertough materials

    Science.gov (United States)

    Shishkin, E. V.; Kazakov, S. V.

    2017-10-01

    This article describes the results of theoretical and experimental studies of a vibratory-percussion crusher, which is driven from a pair of self-synchronizing vibration exciters, attached to the shell symmetrically about its vertical axis. In addition to that, crusher’s dynamic model is symmetrical and balanced. Forced oscillation laws for crusher working members and their amplitude-frequency characteristics have been inducted. Domains of existence of synchronous opposite-phase oscillations of crusher working members (crusher’s operating mode) and crusher capabilities have been identified. The results of mechanical and technological tests of a pilot crusher presented in the article show that this crusher may be viewed as an advanced machine for disintegration of supertough materials with minimum regrinding of finished products.

  17. Design and fabrication of a biomimetic gyroscope inspired by the fly’s haltere

    NARCIS (Netherlands)

    Droogendijk, H.; Brookhuis, Robert Anton; de Boer, Meint J.; Sanders, Remco G.P.; Krijnen, Gijsbertus 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

  18. Design and fabrication of a biomimetic gyroscope inspired by the fly's haltere

    NARCIS (Netherlands)

    Droogendijk, H.; Brookhuis, Robert Anton; de Boer, Meint J.; Sanders, Remco G.P.; Krijnen, Gijsbertus 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

  19. Towards a biomimetic gyroscope inspired by the fly's haltere using microelectromechanical systems technology

    NARCIS (Netherlands)

    Droogendijk, H.; Brookhuis, Robert Anton; de Boer, Meint J.; Sanders, Remco G.P.; Krijnen, Gijsbertus 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

  20. Analysis of the gyroscopic stabilization of a system of rigid bodies

    DEFF Research Database (Denmark)

    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...

  1. Reproducibility of a 3-dimensional gyroscope in measuring shoulder anteflexion and abduction

    NARCIS (Netherlands)

    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

  2. Vision sensor and dual MEMS gyroscope integrated system for attitude determination on moving base

    Science.gov (United States)

    Guo, Xiaoting; Sun, Changku; Wang, Peng; Huang, Lu

    2018-01-01

    To determine the relative attitude between the objects on a moving base and the base reference system by a MEMS (Micro-Electro-Mechanical Systems) gyroscope, the motion information of the base is redundant, which must be removed from the gyroscope. Our strategy is to add an auxiliary gyroscope attached to the reference system. The master gyroscope is to sense the total motion, and the auxiliary gyroscope is to sense the motion of the moving base. By a generalized difference method, relative attitude in a non-inertial frame can be determined by dual gyroscopes. With the vision sensor suppressing accumulative drift of the MEMS gyroscope, the vision and dual MEMS gyroscope integration system is formed. Coordinate system definitions and spatial transform are executed in order to fuse inertial and visual data from different coordinate systems together. And a nonlinear filter algorithm, Cubature Kalman filter, is used to fuse slow visual data and fast inertial data together. A practical experimental setup is built up and used to validate feasibility and effectiveness of our proposed attitude determination system in the non-inertial frame on the moving base.

  3. Gravity Probe B: Examining Einstein's Spacetime with Gyroscopes. An Educator's Guide with Activities in Space Science.

    Science.gov (United States)

    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)…

  4. Z-Axis Micromachined Tuning Fork Gyroscope with Low Air Damping

    Directory of Open Access Journals (Sweden)

    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.

  5. Temperature compensation method using readout signals of ring laser gyroscope.

    Science.gov (United States)

    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.

  6. Air-Core Photonic-Bandgap Fiber-Optic Gyroscope

    Science.gov (United States)

    Kim, Hyang Kyun; Digonnet, Michel J. F.; Kino, Gordon S.

    2006-08-01

    We report the demonstration of the first air-core photonic-bandgap fiber gyroscope. Because the optical mode in the sensing coil travels largely through air, which has much smaller Kerr, Faraday, and thermal constants than silica, far lower dependencies on power, magnetic field, and temperature fluctuations are predicted. With a 235-m fiber coil, we observe a minimum detectable rotation rate of ~2.7°/h and a long-term stability of ~2°/h, which are consistent with the Rayleigh backscattering coefficient of the fiber and comparable to that measured with a conventional fiber.

  7. Penile vibratory stimulation in the recovery of urinary continence and erectile function after nerve‐sparing radical prostatectomy: a randomized, controlled trial

    National Research Council Canada - National Science Library

    Fode, Mikkel; Borre, Michael; Ohl, Dana A; Lichtbach, Jonas; Sønksen, Jens

    2014-01-01

    To examine the effect of penile vibratory stimulation (PVS) in the preservation and restoration of erectile function and urinary continence in conjunction with nerve-sparing radical prostatectomy (RP...

  8. Optimal Design of a Center Support Quadruple Mass Gyroscope (CSQMG).

    Science.gov (United States)

    Zhang, Tian; Zhou, Bin; Yin, Peng; Chen, Zhiyong; Zhang, Rong

    2016-04-28

    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.

  9. Track Detection in Railway Sidings Based on MEMS Gyroscope Sensors

    Science.gov (United States)

    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

  10. Optimal Design of a Center Support Quadruple Mass Gyroscope (CSQMG

    Directory of Open Access Journals (Sweden)

    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.

  11. Transient Vibration of Gyroscopic Systems with Unsteady Superposed Motion

    Science.gov (United States)

    Wickert, J. A.

    1996-09-01

    The equation of motion for a gyroscopic system with unsteady superposed motion is derived for the prototypical problem in which motion of an oscillating particle is measured relative to a non-inertial frame. The resulting coefficient matrices are time-dependent, and skew-symmetric acceleration terms are present both as Coriolis acceleration and as a component of net stiffness. Such mathematical structure is also demonstrated in the context of other unsteady gyroscopic systems, including flexible media that translate with time-dependent speed. Following the asymptotic approach of Krylov, Bogoliubov, and Mitropolsky, a perturbation method is developed for the case in which the superposed motion varies slowly when viewed on the time scale of the system's natural periods of oscillation. First-order approximations for the modal amplitude and phase are obtained in closed form. The method is illustrated through two examples of technical interest: a two-degree-of-freedom model of a rotating shaft, and a distributed parameter model of a moving tape or web.

  12. Optimization of the geometrical stability in square ring laser gyroscopes

    CERN Document Server

    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...

  13. Track Detection in Railway Sidings Based on MEMS Gyroscope Sensors

    Directory of Open Access Journals (Sweden)

    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.

  14. Vibratory stimulation from powered-toothbrush: A novel approach for orthodontic pain reduction after initial archwire placement

    Directory of Open Access Journals (Sweden)

    Pradeep Raghav

    2015-01-01

    Full Text Available Introduction: Vibratory stimulation has been reported as an effective means in reducing the orthodontic pain. The aim of this study was to evaluate the effectiveness of vibratory stimulation from powered-toothbrushes as a noninvasive and nonpharmacological method of reducing pain caused after initial archwire placement and to compare it with other common modalities of management. Materials and Methods: This clinical trial included 75 patients of age 13–25 years, scheduled for fixed mechanotherapy. Patients were divided into five groups: Control, placebo multivitamin, paracetamol, chewing-gum (Cg, and powered-toothbrush. After placement of 0.016″ Nickel Titanium initial archwire (upper/lower in each patient, the discomfort perceived at 2 h, 6 h, bedtime, 24 h, 2 days, 3 days, and 7 days were marked individually using Wong-Baker (0–5 and numeric (0–10 pain rating scales. Kruskal–Wallis test, Friedman test, unpaired t-test were used for statistical analysis. Results: Vibratory stimulation from powered-toothbrushes effectively reduced pain after initial archwire placement. It did not alter the pattern of pain perception, but significantly reduced the overall intensity of pain at each time interval. Cg was not found effective enough to be recommended as a routine treatment modality. Conclusion: Powered-toothbrushes can be recommended as a nonpharmacological and noninvasive substitute for nonsteroidal anti-inflammatory drugs for effective pain reduction in the clinical practice.

  15. Perception of Frequency, Amplitude and Azimuth of a Vibratory Dipole-Source by the Octavolateralis System of Goldfish (Carassius auratus)

    Science.gov (United States)

    Dailey, Deena D.; Braun, Christopher B.

    2011-01-01

    Goldfish (Carassius auratus) were conditioned to suppress respiration to a 40 Hz vibratory source and subsequently tested for stimulus generalization to frequency, stimulus amplitude and position (azimuth). Animals completely failed to generalize to frequencies separated by octave intervals, both lesser and greater than the CS. However they did appear to generalize weakly to an aerial loudspeaker stimulus of the same frequency (40 Hz) after conditioning with an underwater vibratory source. Animals had a gradually decreasing amount of generalization to amplitude changes, suggesting a perceptual dimension of loudness. Animals generalized largely or completely to the same underwater source presented at a range of source azimuths. When these azimuths were presented at a transect of 3 cm, some animals did show decrements in generalization, while others did not. This suggests that although azimuth may be perceived more saliently at distances closer to a dipole source, perception of position is not immediately salient in conditioned vibratory source detection. Differential responding to test stimuli located towards the head or tail suggests the presence of perceptual differences between sources that are rostral or caudal with respect to the position of the animal or perhaps the head. PMID:21574689

  16. Fiber optic gyroscope dynamic north-finder algorithm modeling and analysis based on Simulink

    Science.gov (United States)

    Zhang, Zhengyi; Liu, Chuntong

    2017-09-01

    In view of the problems such as the lower automation level and the insufficient precision of the traditional fiber optic gyroscope (FOG) static north-finder, this paper focuses on the in-depth analysis of the FOG dynamic north-finder principle and algorithm. The simulation model of the FOG dynamic north found algorithm with the least square method by points is established using Simulink toolbox, and then the platform rotation speed and sampling frequency, which affect FOG dynamic north found precision obviously, are simulated and calculated, and the optimization analysis is carried out as a key consideration. The simulation results show that, when the platform rotation speed is between 4.5 °/s and 8.5 °/s and the sampling frequency is at about 50 Hz in the case of using the parameters of this paper, the FOG dynamic north finding system can reach the higher precision. And the conclusions can provide the reference and validation for the engineering and practical of FOG dynamic north-finder.

  17. Experimental analysis of the dynamic north-finding method based on a fiber optic gyroscope.

    Science.gov (United States)

    Zhou, Zhu; Tan, Zhongwei; Wang, Xinyue; Wang, Ziyu

    2017-08-10

    This paper demonstrates the principles of static and dynamic north-finding methods by measuring the projection of the Earth's rotation rate with a fiber optic gyroscope. For a comprehensive comparison of the two methods, the influence of a closed-loop feedback mechanism of a servo motor in a turntable is taken into consideration. Thus, we proposed the static and dynamic north-finding experimental implementations according to the different impact of the motor jitters and the different seeking times. Experimental results show that the dynamic method can reduce the north-finding bias error and instability by 60.1% and 54.6%, respectively, in the seeking time of 360 s, while the reduced proportions are 81.3% and 82.5%, respectively, in the seeking time of 120 s, compared with the static method under the jittering effect of the turntable. Therefore, it can be concluded that the dynamic method is more accurate and robust to the jittering effect.

  18. The GINGERino ring laser gyroscope, seismological observations at one year from the first light

    Science.gov (United States)

    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.

  19. Design of orienting and aiming instrument based on fiber optic gyroscope

    Science.gov (United States)

    Zhang, Zhijun; Wang, Limin; Sun, Jiyu

    2007-12-01

    In order to improve the ground viability of missile weapon system, a quick orienting and aiming instrument is cried for the missile launching in modern war. The fiber optic gyroscope (FOG) based on Sagnac effect is a new type of all solid state rotation rate sensor that detects angular changes or angular rates relative to inertial space, which has many fine characteristics compared with traditional mechanical electronic gyro, such as low cost, light weight, long life, high reliability, wide dynamic range, etc. For the need of missile photoelectric aiming facility, It is necessary to design and manufacture a set of orienting and aiming instrument based on single axis FOG, to solve the close quarters aiming of missile launching, to measure the azimuth reference. Based on practical project, the principle of FOG orienting system and laser collimation theodolite aiming system is discussed and studied in this paper. Orienting and aiming system are constructed in the same basement. The influence of platform tilt on the precision of orientation is analyzed. An accelerator is used to compensate deviation caused by base tilt. The aiming precision affected by eccentricity of the encoders for laser collimation theodolite and the FOG orientation system are analyzed. The test results show that the aiming accuracy is 6' in three minutes. It is suitable for missile aiming in short range.

  20. Separation of water from metal working emulsions by ultrafiltration using vibratory membranes.

    Science.gov (United States)

    Moulai-Mostefa, Nadji; Frappart, Matthieu; Akoum, Omar; Ding, Luhui; Jaffrin, Michel Y

    2010-05-15

    In this paper, we investigate the application of a vibratory shear-enhanced filtration system (VSEP) to separation of water from oil-in-water emulsions. The VSEP module consists in an annular membrane of 500 cm(2) area which oscillates azimuthally in its own plane with an amplitude depending upon frequency. Polyethersulfone (PES) membranes of 50 and 20 kDa were used. Test fluids consisted of oil-in-water emulsion at an oil concentration of 4% prepared from a concentrated cutting fluid. The critical flux for stable operation was investigated by increasing the permeate flux in steps while monitoring the transmembrane pressure (TMP). With a 50 kDa membrane the flux increased nonlinearly with TMP and reached 250 L h(-1)m(-2) at a TMP of 1500 kPa while permeate turbidity decayed from 1.8 to 0.9 NTU above 600 kPa from an initial emulsion turbidity of 21,900 NTU. With the 20 kDa membrane, the flux increased linearly with TMP until 1600 kPa, but the oil concentration in permeate became negligible (turbidity near zero NTU). Concentration tests showed that the flux decreased linearly with ln(VRR) where VRR is the volume reduction ratio while permeate turbidity increased exponentially to 25NTU above a VRR of 4. This work confirms the high performance of the VSEP for oil separation from water in metal working emulsions. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  1. A high-efficiency self-powered wireless sensor node for monitoring concerning vibratory events

    Science.gov (United States)

    Xu, Dacheng; Li, Suiqiong; Li, Mengyang; Xie, Danpeng; Dong, Chuan; Li, Xinxin

    2017-09-01

    This paper presents a self-powered wireless alarming sensor node (SWASN), which was designed to monitor the occurrence of concerning vibratory events. The major components of the sensor node include a vibration-threshold-triggered energy harvester (VTTEH) that powers the sensor node, a dual threshold voltage control circuit (DTVCC) for power management and a radio frequency (RF) signal transmitting module. The VTTEH generates significant electric energy only when the input vibration reaches certain amplitude. Thus, the VTTEH serves as both the power source and the vibration-event-sensing element for the sensor node. The DTVCC was specifically designed to utilize the limited power supply from the VTTEH to operate the sensor node. Constructed with only voltage detectors and MOSFETs, the DTVCC achieved low power consumption, which was 65% lower compared with the power management circuit designed in our previous work. Meanwhile, a RF transmit circuit was constructed based on the commercially available CC1110-F32 wireless transceiver chip and a compact planar antenna was designed to improve the signal transmission distance. The sensor node was fabricated and was characterized both in the laboratory and in the field. Experimental results showed that the SWASN could automatically send out alarming signals when the simulated concerning event occurred. The waiting time between two consecutive transmission periods is less than 125 s and the transmission distance can reach 1.31 km. The SWASN will have broad applications in field surveillances.

  2. Penile vibratory stimulation and electroejaculation before anticancer therapy in two pubertal boys.

    Science.gov (United States)

    Schmiegelow, M L; Sommer, P; Carlsen, E; Sønksen, J O; Schmiegelow, K; Müller, J R

    1998-01-01

    Because more than 70% of children with cancer become long-term survivors, more emphasis is put on reducing late effects. Cryopreservation of semen and the intracytoplasmic sperm injection technique makes it possible to obtain pregnancy with very poor sperm quality. Two new semen retrieval methods are described that are applicable in pubertal boys with a fertility potential, although not psychologically ready to produce a semen sample, who are likely to become infertile because of anticancer therapy. Two pubertal boys (aged 14 and 15 years) had a late testicular relapse of pre-B acute lymphoblastic leukemia and Hodgkin disease, stage II, respectively. In patient 1, penile vibratory stimulation (PVS) was tried under general anesthesia without success and electroejaculation (EEJ) was performed. Before alkylating chemotherapy and testicular irradiation, PVS was performed with success in patient 2. An antegrade ejaculate of 0.7 ml with 1% motile spermatozoa and an retrograde ejaculate with 1.6 x 10(6)/ml spermatozoa (5% with fair motility) was obtained from patient 1. An antegrade ejaculate of 1.5 ml with 2.5 x 10(6)/ml spermatozoa (29% with fair motility) was obtained from patient 2. PVS should be the first choice of treatment because it is noninvasive, simple, and easily applied. Because EEJ requires general anesthesia, it should be used as a second option.

  3. Penile vibratory stimulation in the treatment of post-prostatectomy incontinence

    DEFF Research Database (Denmark)

    Fode, Mikkel; Sønksen, Jens

    2015-01-01

    AIMS: To examine penile vibratory stimulation (PVS) in the treatment of post-prostatectomy urinary incontinence (UI). METHODS: Patients with post-prostatectomy UI were included in a 12-week trial. A 24-hr pad test and a 72-hr voiding diary were collected at baseline. Participants were randomized...... men were available for analyses. The difference in the change on the pad test between the groups did not reach statistical significance at 6 weeks (P = 0.13) while the change in incontinence episodes between groups approached statistical significance (P = 0.052). However, there was a median reduction...... of -33 g (P = 0.021) on the pad test and a median reduction in daily incontinence episodes of -1 (P = 0.023) in group 1 at 6 weeks. At 12 weeks, group 2 had a median decrease on the pad test of -8 g (P = 0.10) and no change in incontinence episodes. A pooled analysis showed a decline on the pad test...

  4. Modeling of Thermal Phase Noise in a Solid Core Photonic Crystal Fiber-Optic Gyroscope.

    Science.gov (United States)

    Song, Ningfang; Ma, Kun; Jin, Jing; Teng, Fei; Cai, Wei

    2017-10-26

    A theoretical model of the thermal phase noise in a square-wave modulated solid core photonic crystal fiber-optic gyroscope has been established, and then verified by measurements. The results demonstrate a good agreement between theory and experiment. The contribution of the thermal phase noise to the random walk coefficient of the gyroscope is derived. A fiber coil with 2.8 km length is used in the experimental solid core photonic crystal fiber-optic gyroscope, showing a random walk coefficient of 9.25 × 10 -5 deg/√h.

  5. Large-area fiber-optic gyroscope on a multiplexed fiber network.

    Science.gov (United States)

    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.

  6. A SQUID readout system for a superconducting gyroscope. [superconducting quantum interference device

    Science.gov (United States)

    Hendricks, J. B.

    1975-01-01

    A design of a read out system for a superconducting gyroscope to be used in an orbiting gyroscope relativity experiment is discussed. The 'London Moment' of the superconducting rotor, which lies along the spin axis of the rotor, will be measured with a SQUID-type magnetometer. The SQUID will be built around the gyro rotor, with a very close spacing to give an inductance between 10 millionths and 1 millionth Hy. A SQUID of this design should resolve 2.07 times 10 to the minus 19th weber. The angular resolution of the gyroscope will then be 0.0035 arc-second, which is sufficient for the intended experiment.

  7. Modeling of Thermal Phase Noise in a Solid Core Photonic Crystal Fiber-Optic Gyroscope

    Directory of Open Access Journals (Sweden)

    Ningfang Song

    2017-10-01

    Full Text Available A theoretical model of the thermal phase noise in a square-wave modulated solid core photonic crystal fiber-optic gyroscope has been established, and then verified by measurements. The results demonstrate a good agreement between theory and experiment. The contribution of the thermal phase noise to the random walk coefficient of the gyroscope is derived. A fiber coil with 2.8 km length is used in the experimental solid core photonic crystal fiber-optic gyroscope, showing a random walk coefficient of 9.25 × 10−5 deg/√h.

  8. The action principle for generalized fluid motion including gyroviscosity

    CERN Document Server

    Lingam, M

    2014-01-01

    A general set of fluid equations that allow for energy-conserving momentum transport by gyroscopic motion of fluid elements is obtained. The equations are produced by a class of action principles that yield a large subset of the known fluid and magnetofluid models, including gyroviscosity. Analysis of the action principle yields broad, model-independent results regarding the conservation laws of energy and linear and angular momenta. The formalism is illustrated by studying fluid models with intrinsic angular momentum that may appear in the contexts of condensed matter, biological, and other areas of physics.

  9. MEMS gyroscope control using a novel compound robust control.

    Science.gov (United States)

    Rahmani, Mehran

    2018-01-01

    This paper proposes a new compound fractional order integral terminal sliding mode control (FOITSMC) and proportional-derivative control (PD-FOITSMC) for the control of a MEMS gyroscope. In order to improve the robustness of the conventional integral terminal sliding mode control (ITSMC), a fractional integral terminal sliding mode surface is applied. The chattering problem in FOITSMC, which is usually generated by the excitation of fast un-modelled dynamic is the main drawback. A PD controller is employed in order to eliminate chattering phenomenon. The stability of the PD-FOITSMC is proved by Lyapunov theory. The performance of the proposed control method is compared with two other controllers such as ITSMC and FOITSMC. Numerical simulations clearly verified the effectiveness of the proposed control approach. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Classifying Human Leg Motions with Uniaxial Piezoelectric Gyroscopes

    Directory of Open Access Journals (Sweden)

    Kerem Altun

    2009-10-01

    Full Text Available This paper provides a comparative study on the different techniques of classifying human leg motions that are performed using two low-cost uniaxial piezoelectric gyroscopes worn on the leg. A number of feature sets, extracted from the raw inertial sensor data in different ways, are used in the classification process. The classification techniques implemented and compared in this study are: Bayesian decision making (BDM, a rule-based algorithm (RBA or decision tree, least-squares method (LSM, k-nearest neighbor algorithm (k-NN, dynamic time warping (DTW, support vector machines (SVM, and artificial neural networks (ANN. A performance comparison of these classification techniques is provided in terms of their correct differentiation rates, confusion matrices, computational cost, and training and storage requirements. Three different cross-validation techniques are employed to validate the classifiers. The results indicate that BDM, in general, results in the highest correct classification rate with relatively small computational cost.

  11. Spherical gyroscopic moment stabilizer for attitude control of microsatellites

    Science.gov (United States)

    Keshtkar, Sajjad; Moreno, Jaime A.; Kojima, Hirohisa; Uchiyama, Kenji; Nohmi, Masahiro; Takaya, Keisuke

    2018-02-01

    This paper presents a new and improved concept of recently proposed two-degrees of freedom spherical stabilizer for triaxial orientation of microsatellites. The analytical analysis of the advantages of the proposed mechanism over the existing inertial attitude control devices are introduced. The extended equations of motion of the stabilizing satellite including the spherical gyroscope, for control law design and numerical simulations, are studied in detail. A new control algorithm based on continuous high-order sliding mode algorithms, for managing the torque produced by the stabilizer and therefore the attitude control of the satellite in the presence of perturbations/uncertainties, is presented. Some numerical simulations are carried out to prove the performance of the proposed mechanism and control laws.

  12. Assessing bradykinesia in Parkinson's disease using gyroscope signals.

    Science.gov (United States)

    Summa, S; Tosi, J; Taffoni, F; Di Biase, L; Marano, M; Rizzo, A Cascio; Tombini, M; Di Pino, G; Formica, D

    2017-07-01

    Parkinson's disease (PD) is a neurodegenerative brain disorder that slowly brings on the dopaminergic neurons death. The depletion of the dopaminergic signal causes the onset of motor symptoms such as tremor, bradykinesia and rigidity. Usually, neurologists regularly monitor motor symptoms and motor fluctuations using the MDS-UPDRS part III clinical scale. Nevertheless, to have a more objective and quantitative evaluation, it is possible to assess the cardinal motor symptoms of PD using wearable sensors and portable robotic devices. Unfortunately while there are several research papers on the use of these devices on PD patients, their use is not so common in clinical practice. In this work we recorded specific MDS-UPDRS motor tasks using magneto-inertial devices, worn by seven PD subjects and seven age-matched controls, in order to deeply analyze the kinematic and dynamic characteristics of goal-directed movements of upper limb, in addition to extract quantitative indices (peak velocity, smoothness, etc) useful for the assessment of motor symptoms. Using only gyroscope signals we looked at those parameters useful to assess bradykinesia. We observed parameters changes from OFF to ON phase congruent with the MDS-UPDRS changes, especially in the frequency domain. Our results suggest the prono-supination task is the more consistent to describe the bradykinesia symptom with the gyroscopes. Probably because of the amplitude of the movement performed. Moreover the peak power looks appropriate for bradykinesia symptom evaluation. We can conclude that, similar to the studies in which tremor symptom is evaluated, it is possible to monitor the bradykinesia using few wearable sensors and few simple parameters.

  13. Gait event detection on level ground and incline walking using a rate gyroscope.

    Science.gov (United States)

    Catalfamo, Paola; Ghoussayni, Salim; Ewins, David

    2010-01-01

    Gyroscopes have been proposed as sensors for ambulatory gait analysis and functional electrical stimulation systems. Accurate determination of the Initial Contact of the foot with the floor (IC) and the final contact or Foot Off (FO) on different terrains is important. This paper describes the evaluation of a gyroscope placed on the shank for determination of IC and FO in subjects walking outdoors on level ground, and up and down an incline. Performance was compared with a reference pressure measurement system. The mean difference between the gyroscope and the reference was less than -25 ms for IC and less than 75 ms for FO for all terrains. Detection success was over 98%. These results provide preliminary evidence supporting the use of the gyroscope for gait event detection on inclines as well as level walking.

  14. Analysis of the design of a passive resonant miniature optical gyroscope based on integrated optics technologies

    Science.gov (United States)

    Feugnet, Gilles; Ravaille, Alexia; Schwartz, Sylvain; Bretenaker, Fabien

    2017-10-01

    We present a simple analysis of the design of a passive miniature resonant optical gyroscope. By combining the requirements on the angular random walk and the bias stability, we end up with simple expressions of the minimum diameter of the ring waveguide cavity and the maximum power that should be used to probe it. Using state-of-the-art performances of photonic integrated circuit and whispering gallery mode technologies in terms of propagation losses and mode size, we show that tactical grade gyroscope performances can be achieved with a diameter of a few cm provided the detrimental influence of the Kerr effect is mitigated using, for instance, an active control of the unbalance in the intensities. We further extend the analysis to medium performance gyroscope and give some hints on the efforts to be made to potentially demonstrate a miniature resonant optical gyroscope with this level of performance.

  15. The rotational motion of an earth orbiting gyroscope according to the Einstein theory of general relativity

    Science.gov (United States)

    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.

  16. Analysis of coupled resonator optical waveguide gyroscope based on periodically modulated coupling and circumferences

    Science.gov (United States)

    Huang, Jie; Zhang, Hailiang; Yang, Junbo; Zhang, Jingjing; Wu, Wenjun; Chang, Shengli

    2016-12-01

    Based on periodically modulated coupling and circumferences, we developed a new structure for coupled resonator optical waveguide (CROW) gyroscopes. Its sensitivity and resolution were significantly improved. With our new structure, which overcomes the individual limitations of the previous schemes, the sensitivity and resolution of our gyroscope are higher than those with coupling-coefficient modulation alone and circumference modulation alone. The resolution of the gyroscope gradually declines with increasing resonator propagation loss; when the quality factor Q ≤ 2 ×106 , the height of the center resonance peak of the transmission band decreases by more than 90%. Fortunately, this effect can be weakened by increasing the circumference difference. We also numerically analyzed the influence of manufacturing errors on the performance of the gyroscope. We found that the fluctuations of radius have a greater influence than the fluctuations of quality factor.

  17. Penile vibratory stimulation in the treatment of post-prostatectomy incontinence: a randomized pilot study.

    Science.gov (United States)

    Fode, Mikkel; Sønksen, Jens

    2015-02-01

    To examine penile vibratory stimulation (PVS) in the treatment of post-prostatectomy urinary incontinence (UI). Patients with post-prostatectomy UI were included in a 12-week trial. A 24-hr pad test and a 72-hr voiding diary were collected at baseline. Participants were randomized to receive PVS for the first 6 weeks (group 1) or for the final 6 weeks (group 2) of the study. The primary outcome was the difference in leakage between groups 1 and 2 at 6 weeks as measured by changes in the pad test. The trial was registered at www.clinicaltrials.org (NCT01540656). Data from 31 men were available for analyses. The difference in the change on the pad test between the groups did not reach statistical significance at 6 weeks (P = 0.13) while the change in incontinence episodes between groups approached statistical significance (P = 0.052). However, there was a median reduction of -33 g (P = 0.021) on the pad test and a median reduction in daily incontinence episodes of -1 (P = 0.023) in group 1 at 6 weeks. At 12 weeks, group 2 had a median decrease on the pad test of -8 g (P = 0.10) and no change in incontinence episodes. A pooled analysis showed a decline on the pad test of -13.5 g (P = 0.004) after PVS. Small improvements were seen in subjective symptom scores and 58% stated to be satisfied with PVS. Self-limiting side effects were experienced by 15% of patients. PVS is feasible in the treatment of post-prostatectomy UI. Larger trials are needed to document the clinical efficacy. © 2013 Wiley Periodicals, Inc.

  18. A randomized trial of clitoral vacuum suction versus vibratory stimulation in neurogenic female orgasmic dysfunction.

    Science.gov (United States)

    Alexander, Marcalee; Bashir, Khurram; Alexander, Craig; Marson, Lesley; Rosen, Raymond

    2017-09-09

    To examine safety and efficacy of use of a clitoral vacuum suction device (CVSD) versus vibratory stimulation (V) to treat orgasmic dysfunction in women with MS or SCI. Randomized clinical trial. Two academic medical centers. Thirty-one women including 20 with MS and 11 with SCI. A 12-week trial of the use of a CVSD versus V MAIN OUTCOME MEASURES: Female Sexual Function Inventory (FSFI) and Female Sexual Distress Scale (FSDS). 23 women (18 MS; 5 SCI) completed the study including 13/16 randomized to CVSD and 10/15 randomized to V. There was a statistically significant increase in total FSFI score (p=.011), desire (p=. 009), arousal (p=.009), lubrication (p=.008), orgasm (p=.012), and satisfaction (p=.049) and a significant decrease in distress as measured by FSDS (p=.020) in subjects using the CVSD. In subjects who used V, there was a statistically significant increase in the orgasm subscale of the FSFI (p=.028). Subjects using the CVSD maintained improvements 4 weeks after treatment. CVSD is safe and overall efficacious to treat female neurogenic sexual dysfunction related to MS and SCI. V is also safe and efficacious to female neurogenic orgasmic dysfunction; however, results were limited to the active treatment period. Due to ease of access and cost, clinicians can consider use of V for women with MS or SCI with orgasmic dysfunction. CVSD is recommended for women with multiple sexual dysfunctions or for whom V is ineffective. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  19. Development and evaluation of a vibratory-pneumatic pomegranate arils extractor

    Directory of Open Access Journals (Sweden)

    S. M Nassiri

    2017-05-01

    Full Text Available Introduction Iran is a frontier of pomegranate fruit production in the world (with almost 40 % of the world`s production. However due to traditional processing operations is not ranked as the largest pomegranate exporter. Saveh, Neyriz and Ferdows are the top pomegranate producing cities in Iran. Pomegranate is consumed as a fresh fruit as well as processed product as food additive, paste, syrup, jelly, pectin, jam, beverage, essence, vinegar and concentrate. Aril extraction is the first and essential postharvest operation for pomegranate processing. Arils are mostly extracted manually even in large scales for fresh and processed consumption. This labor intensive operation is rational when aril quality is an important index for consumer. But whenever pomegranate juice is desired, the aril quality has no priority for consumer, and therefore arils can be extracted with less care. Sarig (1985 was the first inventor of a pomegranate aril extractor who employed air jet force to extract the arils. Later, other researchers employed the same method as well as water jet to extract fruit juice and sac. In the present study, fabrication and evaluation of vibratory aril extractor augmented with air system was conducted. Materials and Methods The study was conducted using Rabab cultivar samples which were manually harvested from an orchard in Neyriz town, Fars province. Samples were kept in refrigerator at 5 0C till experimental trials. Initial moisture content of fruit skin, arils and internal fleshes were measured by gravimetric method as 31.7±2.6 %, 61.5±1.8 % and 42.8±1.4 %, respectively and for a whole fruit was measured 45.3±11.5 % (w.b.. For conducting laboratory tests, an aril extraction unit was designed and fabricated. It comprised a steel main frame, a 746 W electric motor, drive mechanism (eccentric and shaft, sample retentive unit, air jet unit, aril tank, and an air compressor-tank assembly. Sample retentive unit was designed in such a

  20. Radiation resistant erbium doped fiber for ASE source and fiber gyroscope application

    Science.gov (United States)

    Pinsard, Emmanuel; Laurent, Arnaud; Robin, Thierry; Cadier, Benoît; Ferrand, Sébastien; Bonnefois, Jean-Jacques; Moluçon, Cedric; Boutillier, Mathieu

    2017-11-01

    A radiation resistant optical fiber used in a broadband source is presented. Both ASE source and Fiber Optical Gyroscope (FOG) commonly used in space missions, suffer from failures and degradation after long term exposure to radiative environment. The aim of this article is to present the results of our investigation on fiber and ASE source architecture in order to design a Radiation Resistant Erbium Doped Fiber that offers long term stability of the gyroscope performances.

  1. Design, Fabrication, and Modeling of a Novel Dual-Axis Control Input PZT Gyroscope

    Directory of Open Access Journals (Sweden)

    Cheng-Yang Chang

    2017-10-01

    Full Text Available Conventional gyroscopes are equipped with a single-axis control input, limiting their performance. Although researchers have proposed control algorithms with dual-axis control inputs to improve gyroscope performance, most have verified the control algorithms through numerical simulations because they lacked practical devices with dual-axis control inputs. The aim of this study was to design a piezoelectric gyroscope equipped with a dual-axis control input so that researchers may experimentally verify those control algorithms in future. Designing a piezoelectric gyroscope with a dual-axis control input is more difficult than designing a conventional gyroscope because the control input must be effective over a broad frequency range to compensate for imperfections, and the multiple mode shapes in flexural deformations complicate the relation between flexural deformation and the proof mass position. This study solved these problems by using a lead zirconate titanate (PZT material, introducing additional electrodes for shielding, developing an optimal electrode pattern, and performing calibrations of undesired couplings. The results indicated that the fabricated device could be operated at 5.5±1 kHz to perform dual-axis actuations and position measurements. The calibration of the fabricated device was completed by system identifications of a new dynamic model including gyroscopic motions, electromechanical coupling, mechanical coupling, electrostatic coupling, and capacitive output impedance. Finally, without the assistance of control algorithms, the “open loop sensitivity” of the fabricated gyroscope was 1.82 μV/deg/s with a nonlinearity of 9.5% full-scale output. This sensitivity is comparable with those of other PZT gyroscopes with single-axis control inputs.

  2. Design, Fabrication, and Modeling of a Novel Dual-Axis Control Input PZT Gyroscope.

    Science.gov (United States)

    Chang, Cheng-Yang; Chen, Tsung-Lin

    2017-10-31

    Conventional gyroscopes are equipped with a single-axis control input, limiting their performance. Although researchers have proposed control algorithms with dual-axis control inputs to improve gyroscope performance, most have verified the control algorithms through numerical simulations because they lacked practical devices with dual-axis control inputs. The aim of this study was to design a piezoelectric gyroscope equipped with a dual-axis control input so that researchers may experimentally verify those control algorithms in future. Designing a piezoelectric gyroscope with a dual-axis control input is more difficult than designing a conventional gyroscope because the control input must be effective over a broad frequency range to compensate for imperfections, and the multiple mode shapes in flexural deformations complicate the relation between flexural deformation and the proof mass position. This study solved these problems by using a lead zirconate titanate (PZT) material, introducing additional electrodes for shielding, developing an optimal electrode pattern, and performing calibrations of undesired couplings. The results indicated that the fabricated device could be operated at 5.5±1 kHz to perform dual-axis actuations and position measurements. The calibration of the fabricated device was completed by system identifications of a new dynamic model including gyroscopic motions, electromechanical coupling, mechanical coupling, electrostatic coupling, and capacitive output impedance. Finally, without the assistance of control algorithms, the "open loop sensitivity" of the fabricated gyroscope was 1.82 μV/deg/s with a nonlinearity of 9.5% full-scale output. This sensitivity is comparable with those of other PZT gyroscopes with single-axis control inputs.

  3. On bandwidth characteristics of tuning fork micro-gyroscope with mechanically coupled sense mode.

    Science.gov (United States)

    Ni, Yunfang; Li, Hongsheng; Huang, Libin; Ding, Xukai; Wang, Haipeng

    2014-07-21

    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.

  4. A Rotational Gyroscope with a Water-Film Bearing Based on Magnetic Self-Restoring Effect.

    Science.gov (United States)

    Chen, Dianzhong; Liu, Xiaowei; Zhang, Haifeng; Li, Hai; Weng, Rui; Li, Ling; Rong, Wanting; Zhang, Zhongzhao

    2018-01-31

    Stable rotor levitation is a challenge for rotational gyroscopes (magnetically suspended gyroscopes (MSG) and electrostatically suspended gyroscopes (ESG)) with a ring- or disk-shaped rotor, which restricts further improvement of gyroscope performance. In addition, complicated pick-up circuits and feedback control electronics propose high requirement on fabrication technology. In the proposed gyroscope, a ball-disk shaped rotor is supported by a water-film bearing, formed by centrifugal force to deionized water at the cavity of the lower supporting pillar. Water-film bearing provides stable mechanical support, without the need for complicated electronics and control system for rotor suspension. To decrease sliding friction between the rotor ball and the water-film bearing, a supherhydrophobic surface (SHS) with nano-structures is fabricated on the rotor ball, resulting in a rated spinning speed increase of 12.4% (under the same driving current). Rotor is actuated by the driving scheme of brushless direct current motor (BLDCM). Interaction between the magnetized rotor and the magnetic-conducted stator produces a sinusoidal rotor restoring torque, amplitude of which is proportional to the rotor deflection angle inherently. Utilization of this magnetic restoring effect avoids adding of a high amplitude voltage for electrostatic feedback, which may cause air breakdown. Two differential capacitance pairs are utilized to measure input angular speeds at perpendicular directions of the rotor plane. The bias stability of the fabricated gyroscope is as low as 0.5°/h.

  5. On Bandwidth Characteristics of Tuning Fork Micro-Gyroscope with Mechanically Coupled Sense Mode

    Directory of Open Access Journals (Sweden)

    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.

  6. A Rotational Gyroscope with a Water-Film Bearing Based on Magnetic Self-Restoring Effect

    Directory of Open Access Journals (Sweden)

    Dianzhong Chen

    2018-01-01

    Full Text Available Stable rotor levitation is a challenge for rotational gyroscopes (magnetically suspended gyroscopes (MSG and electrostatically suspended gyroscopes (ESG with a ring- or disk-shaped rotor, which restricts further improvement of gyroscope performance. In addition, complicated pick-up circuits and feedback control electronics propose high requirement on fabrication technology. In the proposed gyroscope, a ball-disk shaped rotor is supported by a water-film bearing, formed by centrifugal force to deionized water at the cavity of the lower supporting pillar. Water-film bearing provides stable mechanical support, without the need for complicated electronics and control system for rotor suspension. To decrease sliding friction between the rotor ball and the water-film bearing, a supherhydrophobic surface (SHS with nano-structures is fabricated on the rotor ball, resulting in a rated spinning speed increase of 12.4% (under the same driving current. Rotor is actuated by the driving scheme of brushless direct current motor (BLDCM. Interaction between the magnetized rotor and the magnetic-conducted stator produces a sinusoidal rotor restoring torque, amplitude of which is proportional to the rotor deflection angle inherently. Utilization of this magnetic restoring effect avoids adding of a high amplitude voltage for electrostatic feedback, which may cause air breakdown. Two differential capacitance pairs are utilized to measure input angular speeds at perpendicular directions of the rotor plane. The bias stability of the fabricated gyroscope is as low as 0.5°/h.

  7. Implementation of the resonant vibratory feeders control algorithm on Simatic S7-1200 from MATLAB Simulink enviroment

    Directory of Open Access Journals (Sweden)

    Mitrović Radomir B.

    2016-01-01

    Full Text Available Simulink is an important tool for modeling and simulation of process and control algorithms. It's expansion, PLC Coder, enables direct conversion of model subsystem into SCL, structured text code, which is then used by PLC IDE to create function blocks. This shortens developing time of algorithms for PLC controller. Also, this reduces possibility for a coding error. This paper describes Simulink PLC Coder and workflow for developing PID control algorithm for Siemens Simatic S7-1200 PLC. Control object used here is resonant vibratory feeder having electromagnetic drive.

  8. Penile vibratory stimulation in the recovery of urinary continence and erectile function after nerve-sparing radical prostatectomy

    DEFF Research Database (Denmark)

    Fode, Mikkel; Borre, Michael; Ohl, Dana A

    2014-01-01

    OBJECTIVE: To examine the effect of penile vibratory stimulation (PVS) in the preservation and restoration of erectile function and urinary continence in conjunction with nerve-sparing radical prostatectomy (RP). PATIENTS AND METHODS: The present study was conducted between July 2010 and March 2013...... and 12 months after surgery with the IIEF-5 questionnaire and questions regarding urinary bother. Patients using up to one pad daily for security reasons only were considered continent. The study was registered at http://clinicaltrials.gov/ (NCT01067261). RESULTS: Data from 68 patients were available...

  9. Super-large optical gyroscopes for applications in geodesy and seismology: state-of-the-art and development prospects

    Energy Technology Data Exchange (ETDEWEB)

    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)

  10. Modelling of soldier fly halteres for gyroscopic oscillations.

    Science.gov (United States)

    Parween, Rizuwana; Pratap, Rudra

    2015-01-08

    Nature has evolved a beautiful design for small-scale vibratory rate-gyro in the form of dipteran halteres that detect body rotations via Coriolis acceleration. In most Diptera, including soldier fly, Hermetia illucens, halteres are a pair of special organs, located in the space between the thorax and the abdomen. The halteres along with their connecting joint with the fly's body constitute a mechanism that is used for muscle-actuated oscillations of the halteres along the actuation direction. These oscillations lead to bending vibrations in the sensing direction (out of the haltere's actuation plane) upon any impressed rotation due to the resulting Coriolis force. This induced vibration is sensed by the sensory organs at the base of the haltere in order to determine the rate of rotation. In this study, we evaluate the boundary conditions and the stiffness of the anesthetized halteres along the actuation and the sensing direction. We take several cross-sectional SEM (scanning electron microscope) images of the soldier fly haltere and construct its three dimensional model to get the mass properties. Based on these measurements, we estimate the natural frequency along both actuation and sensing directions, propose a finite element model of the haltere's joint mechanism, and discuss the significance of the haltere's asymmetric cross-section. The estimated natural frequency along the actuation direction is within the range of the haltere's flapping frequency. However, the natural frequency along the sensing direction is roughly double the haltere's flapping frequency that provides a large bandwidth for sensing the rate of rotation to the soldier flies. © 2015. Published by The Company of Biologists Ltd.

  11. Modelling of soldier fly halteres for gyroscopic oscillations

    Directory of Open Access Journals (Sweden)

    Rizuwana Parween

    2015-01-01

    Full Text Available Nature has evolved a beautiful design for small-scale vibratory rate-gyro in the form of dipteran halteres that detect body rotations via Coriolis acceleration. In most Diptera, including soldier fly, Hermetia illucens, halteres are a pair of special organs, located in the space between the thorax and the abdomen. The halteres along with their connecting joint with the fly's body constitute a mechanism that is used for muscle-actuated oscillations of the halteres along the actuation direction. These oscillations lead to bending vibrations in the sensing direction (out of the haltere's actuation plane upon any impressed rotation due to the resulting Coriolis force. This induced vibration is sensed by the sensory organs at the base of the haltere in order to determine the rate of rotation. In this study, we evaluate the boundary conditions and the stiffness of the anesthetized halteres along the actuation and the sensing direction. We take several cross-sectional SEM (scanning electron microscope images of the soldier fly haltere and construct its three dimensional model to get the mass properties. Based on these measurements, we estimate the natural frequency along both actuation and sensing directions, propose a finite element model of the haltere's joint mechanism, and discuss the significance of the haltere's asymmetric cross-section. The estimated natural frequency along the actuation direction is within the range of the haltere's flapping frequency. However, the natural frequency along the sensing direction is roughly double the haltere's flapping frequency that provides a large bandwidth for sensing the rate of rotation to the soldier flies.

  12. Gamescape Principles

    DEFF Research Database (Denmark)

    Nobaew, Banphot; Ryberg, Thomas

    2011-01-01

    developed by Buckingham. It supplements and extends this framework by offering a more detailed account of how visual principles and elements in games can be analysed. In developing this visual grammar we draw theoretically on existing approaches within: the arts, history, film study, semiotics, multimodal...... and interviews) collected during a game workshop where students, studying to become game designers, developed a number of games. The visual digital literacy framework we propose consists of five main major components: Gamescape Principles, Interpretation, Style, Experiences and Practices. For the purpose...... of this paper we emphasise the gamescape principles dimension, which focuses on the analysis of the visual elements and principles. The framework will open for new ways of conducting in-depth analysis of the basic elements of 3D games, as a means of better understanding visual digital media and game literacy...

  13. THE STABILIZATION SYSTEM ON PAYLOAD BUILT ON A DYNAMICALLY TUNED GYROSCOPE

    Directory of Open Access Journals (Sweden)

    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. 

  14. [Establishment and accuracy examination of gyroscope for recording and transferring natural head position].

    Science.gov (United States)

    Liu, Xiao-jing; Li, Qian-gian; Tian, Kai-yue; Wang, Xiao-xia; Zhang, Yi; Li, Zi-li

    2014-02-18

    To build up and validate a system based on gyroscope to record human natural head position (NHP) and to transfer it into virtual surgical design system. Three dimensional (3D) mechanical gyroscope and 3D design software were integrated in the system. The protocol for recording and transforming NHP included four steps. Firstly, the gyroscope was CT scanned when its position was (0, 0, 0), a virtual model was built up by 3D reconstruction and considered as standard gyroscope model. Secondly, the gyroscope was bounded to the patient's head using bite-jid and face bow. The NHP was recorded when the patient was looking himself into mirror. Thirdly, the virtual head of the patient was overlapped with standard gyroscope model. Finally, when pitch, roll and yaw of NHP were applied to the compound model, the virtual head was orientated to NHP. A standard cube model was used to validate the accuracy of the system. The cube was positioned 30 times, the real and virtual pitch, roll and yaw angles were recorded. The accuracy of the system was presented by the mean ± SD of the Delta. the difference between the real and virtual pitch, roll and yaw angles were analyzed by paired t test,and their correlations were investigated by Pearson test. The accuracy rates of the system were ΔPitch = 0.03 ± 0.28°,ΔRoll = 0.03 ± 0.23°,ΔYaw = 0.07 ± 0.49°. There were no significant differences between the real and virtual pitch, roll and yaw angles (P > 0.05). The two positions were absolutely correlated at the level of α = 0.01 (2-tailed, r = 1.00). The method of recording and transforming NHP using gyroscope is clinically applicable. The accuracy of transferring system meets the needs of virtual surgical design.

  15. Use Videostrobokymography to Quantitatively Analyze the Vibratory Characteristics Before and After Conservative Medical Treatment of Vocal Fold Leukoplakia.

    Science.gov (United States)

    Gao, Xiao-Wei; Huang, Yong-Wang; Liu, Li-Yan; Ouyang, Jie

    2016-03-01

    To quantitatively analyze the vibratory characteristics of vocal folds before and after conservative treatments to evaluate the outcomes of conservative treatments for vocal fold leukoplakia using videostrobokymography (VSK). This is a prospective study. Twenty patients and 20 controls were enrolled into the study. All patients received conservative treatments for 3 weeks and received VSK examination before and 3 weeks after the treatments. All controls only received VSK examination once. Vocal fold lengths of 25%, 50%, and 75% were chosen as the line-scan positions to evaluate the vocal fold vibration. Open quotient (OQ) and asymmetry index (AI) were obtained using VSK. Significant improvements in the main symptoms including voice hoarseness were found. Videostroboscopic findings showed that the white lesions on the vocal folds almost completely disappeared in all patients, and the vocal fold flexibility returned to normal. All OQs and AIs at each line-scan position in patients before the treatments were larger than those in controls (P  0.017). VSK could quantitatively evaluate the vibratory characteristics of vocal folds before and after the treatments, and conservative treatment could improve VSK measurements to normal control values, suggesting that VSK is a tool to assess the outcomes of the conservative treatments for vocal fold leukoplakia. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  16. Design and Simulation of a New Decoupled Micromachined Gyroscope

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. The stabilization system of primary oscillation for a micromechanical gyroscope

    Science.gov (United States)

    Baranov, Pavel; Nesterenko, Tamara; Tsimbalist, Edvard; Vtorushin, Sergey

    2017-06-01

    The mode of primary oscillations of a micromechanical gyroscope (MMG) sensor is provided by an electrostatic comb-drive actuator in which the interaction between the micromechanical structures and electronics occurs by means of a single or differential capacitive sensor. Two pairs of capacitive sensors are traditionally used for frequency stabilization of MMG primary oscillations. The first pair of capacitive sensors excites primary oscillations, while the second measures the amplitude of primary oscillations. The stabilization system provides a continuous frequency tuning of primary oscillations that increases the duration of transition processes, the time of operational readiness, and the instability of the output signal from the secondary oscillation channel of the MMGs. This paper presents a new approach to the primary oscillation control system of the two-component MMG. The method of calculating the natural resonant frequency is based on measurements of the total current passing through the comb-driver actuator capacitances, and a lock-in detection is suggested. This paper consists of the results of the numerical analysis, the description of the proposed approach to the frequency control of the primary MMG oscillations, and the Simulink model of the behaviour of the MMG stabilization system, depending on its mechanical-and-physical properties with regard to a 2% shift of the natural resonant frequency. The frequency control of the primary oscillations at 2% frequency detuning is performed within 0.11 s.

  18. Atrial Fibrillation Detection via Accelerometer and Gyroscope of a Smartphone.

    Science.gov (United States)

    Lahdenoja, Olli; Hurnanen, Tero; Iftikhar, Zuhair; Nieminen, Sami; Knuutila, Timo; Saraste, Antti; Kiviniemi, Tuomas; Vasankari, Tuija; Airaksinen, Juhani; Pankaala, Mikko; Koivisto, Tero

    2018-01-01

    We present a smartphone-only solution for the detection of atrial fibrillation (AFib), which utilizes the built-in accelerometer and gyroscope sensors [inertial measurement unit, (IMU)] in the detection. Depending on the patient's situation, it is possible to use the developed smartphone application either regularly or occasionally for making a measurement of the subject. The smartphone is placed on the chest of the patient who is adviced to lay down and perform a noninvasive recording, while no external sensors are needed. After that, the application determines whether the patient suffers from AFib or not. The presented method has high potential to detect paroxysmal ("silent") AFib from large masses. In this paper, we present the preprocessing, feature extraction, feature analysis, and classification results of the envisioned AFib detection system based on clinical data acquired with a standard mobile phone equipped with Google Android OS. Test data was gathered from 16 AFib patients (validated against ECG), as well as a control group of 23 healthy individuals with no diagnosed heart diseases. We obtained an accuracy of 97.4% in AFib versus healthy classification (a sensitivity of 93.8% and a specificity of 100%). Due to the wide availability of smart devices/sensors with embedded IMU, the proposed methods could potentially also scale to other domains such as embedded body-sensor networks.

  19. Online technique for detecting state of onboard fiber optic gyroscope

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Gyroscope pivot bearing dimension and surface defect detection.

    Science.gov (United States)

    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.

  1. Gyroscope Pivot Bearing Dimension and Surface Defect Detection

    Directory of Open Access Journals (Sweden)

    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.

  2. Realtime assessment of foot orientation by Accelerometers and Gyroscopes

    Directory of Open Access Journals (Sweden)

    Seel Thomas

    2015-09-01

    Full Text Available Foot orientation can be assessed in realtime by means of a foot-mounted inertial sensor. We consider a method that uses only accelerometer and gyroscope readings to calculate the foot pitch and roll angle, i.e. the foot orientation angle in the sagittal and frontal plane, respectively. Since magnetometers are avoided completely, the method can be used indoors as well as in the proximity of ferromagnetic material and magnetic disturbances. Furthermore, we allow for almost arbitrary mounting orientation in the sense that we only assume one of the local IMU coordinate axes to lie in the sagittal plane of the foot. The method is validated with respect to a conventional optical motion capture system in trials with transfemoral amputees walking with shoes and healthy subjects walking barefoot, both at different velocities. Root mean square deviations of less than 4° are found in all scenarios, while values near 2° are found in slow shoe walking. This demonstrates that the proposed method is suitable for realtime application such as the control of FES-based gait neuroprostheses and active orthoses.

  3. ATMOSPHERE PRESSURE EFFECT ON THE FIBER OPTIC GYROSCOPE OUTPUT SYGNAL

    Directory of Open Access Journals (Sweden)

    Ilya A. Sharkov

    2017-05-01

    Full Text Available The paper describes research results of the atmospheric pressure effect on the output signal of a fiber optic gyroscope (FOG. In the course of experiments, FOG was placed into a hermetic chamber. The atmosphere pressure was varying in the range from 0.8 to 1.5 atm. All the data, including the FOG output signal, temperature, and data from the pressure sensor installed inside the FOG, were synchronously registered with the computer software. The separation of scale factor change from zero offset in the experiment was carried out by setting the sensitive FOG axis at 0°, 90° and 270° relative to the East (the FOG was set perpendicular to the horizon. After the data processing it was concluded that the FOG signal error associated with the pressure affects mainly on the additive component. The pressure effect on the multiplicative component appeared to be negligible at rotational velocities used in the experiment (0 - 130 /h. At the same time, the FOG signal has a high linear correlation coefficient with the derivative of pressure over time (in some cases, more than 0.9. The experiment was repeated several times and the high degree of the drift repeatability was shown. That makes it possible to implement the compensation algorithm. Application of the simplest algorithmic compensation based on the polynomial of the first degree (ax + b enabled to reduce the root-mean-square (RMS and drift of the signal by 2-9 times.

  4. A Digitalized Gyroscope System Based on a Modified Adaptive Control Method.

    Science.gov (United States)

    Xia, Dunzhu; Hu, Yiwei; Ni, Peizhen

    2016-03-04

    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.

  5. MEMS 3-DoF gyroscope design, modeling and simulation through equivalent circuit lumped parameter model

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. The design of photoelectric signal processing system for a nuclear magnetic resonance gyroscope based on FPGA

    Science.gov (United States)

    Zhang, Xian; Zhou, Binquan; Li, Hong; Zhao, Xinghua; Mu, Weiwei; Wu, Wenfeng

    2017-10-01

    Navigation technology is crucial to the national defense and military, which can realize the measurement of orientation, positioning, attitude and speed for moving object. Inertial navigation is not only autonomous, real-time, continuous, hidden, undisturbed but also no time-limited and environment-limited. The gyroscope is the core component of the inertial navigation system, whose precision and size are the bottleneck of the performance. However, nuclear magnetic resonance gyroscope is characteristic of the advantage of high precision and small size. Nuclear magnetic resonance gyroscope can meet the urgent needs of high-tech weapons and equipment development of new generation. This paper mainly designs a set of photoelectric signal processing system for nuclear magnetic resonance gyroscope based on FPGA, which process and control the information of detecting laser .The photoelectric signal with high frequency carrier is demodulated by in-phase and quadrature demodulation method. Finally, the processing system of photoelectric signal can compensate the residual magnetism of the shielding barrel and provide the information of nuclear magnetic resonance gyroscope angular velocity.

  7. Bandwidth optimization design of a multi degree of freedom MEMS gyroscope.

    Science.gov (United States)

    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.

  8. A Digitalized Gyroscope System Based on a Modified Adaptive Control Method

    Directory of Open Access Journals (Sweden)

    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.

  9. MEMS 3-DoF gyroscope design, modeling and simulation through equivalent circuit lumped parameter model

    Science.gov (United States)

    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.

  10. Towards a fully integrated optical gyroscope using whispering gallery modes resonators

    Science.gov (United States)

    Amrane, T.; Jager, J.-B.; Jager, T.; Calvo, V.; Léger, J.-M.

    2017-11-01

    Since the developments of lasers and the optical fibers in the 70s, the optical gyroscopes have been subject to an intensive research to improve both their resolution and stability performances. However the best optical gyroscopes currently on the market, the ring laser gyroscope and the interferometer fiber optic gyroscope are still macroscopic devices and cannot address specific applications where size and weight constraints are critical. One solution to overcome these limitations could be to use an integrated resonator as a sensitive part to build a fully Integrated Optical Resonant Gyroscope (IORG). To keep a high rotation sensitivity, which is usually degraded when downsizing this kind of optical sensors based on the Sagnac effect, the resonator has to exhibit a very high quality factor (Q): as detailed in equation (1) where the minimum rotation rate resolution for an IORG is given as a function of the resonator characteristics (Q and diameter D) and of the global system optical system characteristics (i.e. SNR and bandwidth B), the higher the Q×D product, the lower the resolution.

  11. Laser principles.

    Science.gov (United States)

    Bogdan Allemann, Inja; Kaufman, Joely

    2011-01-01

    Since the construction of the first laser in the 1960s, the role that lasers play in various medical specialities, including dermatology, has steadily increased. However, within the last 2 decades, the technological advances and the use of lasers in the field of dermatology have virtually exploded. Many treatments have only become possible with the use of lasers. Especially in aesthetic medicine, lasers are an essential tool in the treatment armamentarium. Due to better research and understanding of the physics of light and skin, there is now a wide and increasing array of different lasers and devices to choose from. The proper laser selection for each indication and treatment requires a profound understanding of laser physics and the basic laser principles. Understanding these principles will allow the laser operator to obtain better results and help avoid complications. This chapter will give an in-depth overview of the physical principles relevant in cutaneous laser surgery. Copyright © 2011 S. Karger AG, Basel.

  12. Variational principles

    CERN Document Server

    Moiseiwitsch, B L

    2004-01-01

    This graduate-level text's primary objective is to demonstrate the expression of the equations of the various branches of mathematical physics in the succinct and elegant form of variational principles (and thereby illuminate their interrelationship). Its related intentions are to show how variational principles may be employed to determine the discrete eigenvalues for stationary state problems and to illustrate how to find the values of quantities (such as the phase shifts) that arise in the theory of scattering. Chapter-by-chapter treatment consists of analytical dynamics; optics, wave mecha

  13. OPTIMIZATION OF MANUFACTURING TEHNOLOGY FOR “ECCENTRIC MASS” COMPONENT OF A NEW TYPE OF VIBRATORY COMPACTOR USING NX 7.5 SOFTWARE

    Directory of Open Access Journals (Sweden)

    Eftimie Dorin

    2013-11-01

    Full Text Available The paper presents the technological optimization process of the eccentric mass component using the NX 7.5 software. The new design of the vibratory compactor with variable amplitudes was modeled 3D. The manufacturing technology presents graphical aspects of operations during mechanical processing.

  14. Nonreciprocal optical element of ring laser gyroscope based on the effect of light entrainment with moving medium

    Science.gov (United States)

    Gladyshev, V. O.; Goryushkina, D. D.; Kuryatov, V. N.

    2017-11-01

    This article describes the use of Fresnel-Fizeau effect in order to reduce the entrapment effect in a ring laser gyroscope. The study gives an analysis of the nonreciprocal optical element impact on the gyroscope output characteristic. Moreover, it numerically estimates the method’s effectiveness.

  15. "It Has to Go down a Little, in Order to Go around"--Revisiting Feynman on the Gyroscope

    Science.gov (United States)

    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…

  16. A low noise photoelectric signal acquisition system applying in nuclear magnetic resonance gyroscope

    Science.gov (United States)

    Lu, Qilin; Zhang, Xian; Zhao, Xinghua; Yang, Dan; Zhou, Binquan; Hu, Zhaohui

    2017-10-01

    The nuclear magnetic resonance gyroscope serves as a new generation of strong support for the development of high-tech weapons, it solves the core problem that limits the development of the long-playing seamless navigation and positioning. In the NMR gyroscope, the output signal with atomic precession frequency is detected by the probe light, the final crucial photoelectric signal of the probe light directly decides the quality of the gyro signal. But the output signal has high sensitivity, resolution and measurement accuracy for the photoelectric detection system. In order to detect the measured signal better, this paper proposed a weak photoelectric signal rapid acquisition system, which has high SNR and the frequency of responded signal is up to 100 KHz to let the weak output signal with high frequency of the NMR gyroscope can be detected better.

  17. Integrated optical gyroscope using active long-range surface plasmon-polariton waveguide resonator.

    Science.gov (United States)

    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.

  18. Multifrequency excitation method for rapid and accurate dynamic test of micromachined gyroscope chips.

    Science.gov (United States)

    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.

  19. Enhanced sensitivity in a butterfly gyroscope with a hexagonal oblique beam

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Multifrequency Excitation Method for Rapid and Accurate Dynamic Test of Micromachined Gyroscope Chips

    Directory of Open Access Journals (Sweden)

    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.

  1. Adaptive Global Sliding Mode Control for MEMS Gyroscope Using RBF Neural Network

    Directory of Open Access Journals (Sweden)

    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.

  2. Ultrasensitive micro-scale parity-time-symmetric ring laser gyroscope.

    Science.gov (United States)

    Ren, J; Hodaei, H; Harari, G; Hassan, A U; Chow, W; Soltani, M; Christodoulides, D; Khajavikhan, M

    2017-04-15

    We propose a new scheme for ultrasensitive laser gyroscopes that utilizes the physics of exceptional points. By exploiting the properties of such non-Hermitian degeneracies, we show that the rotation-induced frequency splitting becomes proportional to the square root of the gyration speed (Ω), thus enhancing the sensitivity to low angular rotations by orders of magnitudes. In addition, at its maximum sensitivity limit, the measurable spectral splitting is independent of the radius of the rings involved. This Letter paves the way toward a new class of ultrasensitive miniature ring laser gyroscopes on chip.

  3. Bifurcations of Eigenvalues of Gyroscopic Systems with Parameters Near Stability Boundaries

    DEFF Research Database (Denmark)

    Seyranian, Alexander P.; Kliem, Wolfhard

    1999-01-01

    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. It is sh......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...

  4. The spontaneous emission noise limit of active resonator optical waveguide gyroscope

    Science.gov (United States)

    Li, Wenxiu; Zhang, Hao; Lin, Jian; Liu, Jiaming; Xue, Xia; Huang, Anping; Xiao, Zhisong

    2017-10-01

    Active resonators based on optical waveguides can significantly enhance the performance of optical gyroscope due to its loss compensation effect. The spontaneous emission noise (SEN) stemmed from optical gain will broaden the linewidth of the resonator and limit the sensitivity and resolution of active resonator optical gyroscope (AROG). In this paper, we modified the sensitivity formula when the spontaneous emission noise is dominant and analyzed theoretically the performance limitations of the AROG. After considering the spontaneous emission noise source, the resolution can be improved through optimizing the design parameters of the AROG

  5. On the possibility of using the phase characteristic of a ring interferometer in microoptical gyroscopes

    Energy Technology Data Exchange (ETDEWEB)

    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)

  6. Gyroscope vs. accelerometer measurements of motion from wrist PPG during physical exercise

    Directory of Open Access Journals (Sweden)

    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.

  7. Low-Loss Polymer-Based Ring Resonator for Resonant Integrated Optical Gyroscopes

    Directory of Open Access Journals (Sweden)

    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.

  8. Gyroscopic dynamics of antiferromagnetic vortices on domain boundaries of yttrium orthoferrite

    CERN Document Server

    Chetkin, M V; Shapaeva, T B

    2001-01-01

    It is experimentally established that the magnetic field along the b-axis weakly effects the velocity of the antiferromagnetic vortices on the domain boundary of the yttrium orthoferrite and doesn't explain the existence of the essential gyroscopic force, effecting these vortices. The existence of such a force is caused by the dynamic slope of the magnetic sublattices, proportional to the domain boundary velocity. The dynamics of the antiferromagnetic vortices in the yttrium orthoferrite domain boundaries is gyroscopic and quasirelativistic one with the threshold velocity of 20 km/s, equal to the spin waves velocity on the linear section of their dispersion law

  9. Ultrasensitive micro-scale parity-time-symmetric ring laser gyroscope

    Science.gov (United States)

    Ren, J.; Hodaei, H.; Harari, G.; Hassan, A. U.; Chow, W.; Soltani, M.; Christodoulides, D.; Khajavikhan, M.

    2017-04-01

    We propose a new scheme for ultra-sensitive laser gyroscopes that utilizes the physics of exceptional points. By exploiting the properties of such non-Hermitian degeneracies, we show that the rotation-induced frequency splitting becomes proportional to the square root of the gyration speed- thus enhancing the sensitivity to low angular rotations by orders of magnitudes. In addition, at its maximum sensitivity limit, the measurable spectral splitting is independent of the radius of the rings involved. Our work paves the way towards a new class of ultra-sensitive miniature ring laser gyroscopes on chip.

  10. The fiber-optic gyroscope: Challenges to become the ultimate rotation-sensing technology

    Science.gov (United States)

    Lefèvre, Hervé C.

    2013-12-01

    Taking advantage of the development of optical-fiber communication technologies, the fiber-optic gyroscope started to be investigated in the mid 1970s, opening the way for a fully solid-state rotation sensor. It was firstly seen as dedicated to medium-grade applications, but today, it reaches strategic-grade performance and surpasses its well-established competitor, the ring-laser gyroscope, in terms of bias noise and long-term stability. Further progresses remain possible, the challenge being the ultimate inertial navigation performance of one nautical mile per month corresponding to a long-term bias stability of 10-5°/h.

  11. Real-Time Estimation of Pathological Tremor Parameters from Gyroscope Data

    Directory of Open Access Journals (Sweden)

    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.

  12. Real-Time Estimation of Pathological Tremor Parameters from Gyroscope Data

    Science.gov (United States)

    Gallego, Juan A.; Rocon, Eduardo; Roa, Javier O.; Moreno, Juan C.; Pons, José L.

    2010-01-01

    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. PMID:22294919

  13. The Use of Accelerometers and Gyroscopes to Estimate Hip and Knee Angles on Gait Analysis

    Directory of Open Access Journals (Sweden)

    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.

  14. Gyroscope precession along general timelike geodesics in a Kerr black hole spacetime

    Science.gov (United States)

    Bini, Donato; Geralico, Andrea; Jantzen, Robert T.

    2017-06-01

    The precession angular velocity of a gyroscope moving along a general geodesic in the Kerr spacetime is analyzed using the geometric properties of the spacetime. Natural frames along the gyroscope world line are explicitly constructed by boosting frames adapted to fundamental observers. A novel geometrical description is given to Marck's construction of a parallel propagated orthonormal frame along a general geodesic, identifying and clarifying the special role played by the Carter family of observers in this general context, thus extending previous discussion for the equatorial plane case.

  15. Engineering applications and analysis of vibratory motion fourth order fluid film over the time dependent heated flat plate

    Science.gov (United States)

    Mohmand, Muhammad Ismail; Mamat, Mustafa Bin; Shah, Qayyum

    2017-07-01

    This article deals with the time dependent analysis of thermally conducting and Magneto-hydrodynamic (MHD) liquid film flow of a fourth order fluid past a vertical and vibratory plate. In this article have been developed for higher order complex nature fluids. The governing-equations have been modeled in the terms of nonlinear partial differential equations with the help of physical boundary circumstances. Two different analytical approaches i.e. Adomian decomposition method (ADM) and the optimal homotopy asymptotic method (OHAM), have been used for discoveryof the series clarification of the problems. Solutions obtained via two diversemethods have been compared using the graphs, tables and found an excellent contract. Variants of the embedded flow parameters in the solution have been analysed through the graphical diagrams.

  16. Low-frequency vibratory exercise reduces the risk of bone fracture more than walking: a randomized controlled trial.

    Science.gov (United States)

    Gusi, Narcís; Raimundo, Armando; Leal, Alejo

    2006-11-30

    Whole-body vibration (WBV) is a new type of exercise that has been increasingly tested for the ability to prevent bone fractures and osteoporosis in frail people. There are two currently marketed vibrating plates: a) the whole plate oscillates up and down; b) reciprocating vertical displacements on the left and right side of a fulcrum, increasing the lateral accelerations. A few studies have shown recently the effectiveness of the up-and-down plate for increasing Bone Mineral Density (BMD) and balance; but the effectiveness of the reciprocating plate technique remains mainly unknown. The aim was to compare the effects of WBV using a reciprocating platform at frequencies lower than 20 Hz and a walking-based exercise programme on BMD and balance in post-menopausal women. Twenty-eight physically untrained post-menopausal women were assigned at random to a WBV group or a Walking group. Both experimental programmes consisted of 3 sessions per week for 8 months. Each vibratory session included 6 bouts of 1 min (12.6 Hz in frequency and 3 cm in amplitude with 60 degrees of knee flexion) with 1 min rest between bouts. Each walking session was 55 minutes of walking and 5 minutes of stretching. Hip and lumbar BMD (g.cm-2) were measured using dual-energy X-ray absorptiometry and balance was assessed by the blind flamingo test. ANOVA for repeated measurements was adjusted by baseline data, weight and age. After 8 months, BMD at the femoral neck in the WBV group was increased by 4.3% (P = 0.011) compared to the Walking group. In contrast, the BMD at the lumbar spine was unaltered in both groups. Balance was improved in the WBV group (29%) but not in the Walking group. The 8-month course of vibratory exercise using a reciprocating plate is feasible and is more effective than walking to improve two major determinants of bone fractures: hip BMD and balance.

  17. Analysis of a Device for Texturing by Burnishing Using Principles from Axiomatic Design

    Directory of Open Access Journals (Sweden)

    Nagîţ Gheorghe

    2017-01-01

    Full Text Available The vibro-burnishing is a process by means a ball or a roller or other tool active surface is pressed and moved, inclusively by applying a vibratory motion, along the surface to be finished, generating a specific microrelief. A device for vibro-burnishing adapted on a universal lathe was analyzed by means of some principles corresponding to the Axiomatic Design theory. The analysis was developed by adopting some simplifying assumptions and it proved an adequate design, by considering some functional requirements and design parameters specific to the device.

  18. Analysis of frequency response and scale-factor of tuning fork micro-gyroscope operating at atmospheric pressure.

    Science.gov (United States)

    Ding, Xukai; Li, Hongsheng; Ni, Yunfang; Sang, Pengcheng

    2015-01-22

    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.

  19. Cascaded Kalman and particle filters for photogrammetry based gyroscope drift and robot attitude estimation.

    Science.gov (United States)

    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. © 2013 ISA Published by ISA All rights reserved.

  20. On gyroscopic effects in vibrating and axially rotating solid and annular discs

    CSIR Research Space (South Africa)

    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...

  1. Efficiency of a gyroscopic device for conversion of mechanical wave energy to electrical energy

    DEFF Research Database (Denmark)

    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...

  2. Sensor fusion for structural tilt estimation using an acceleration-based tilt sensor and a gyroscope

    Science.gov (United States)

    Liu, Cheng; Park, Jong-Woong; Spencer, B. F., Jr.; Moon, Do-Soo; Fan, Jiansheng

    2017-10-01

    A tilt sensor can provide useful information regarding the health of structural systems. Most existing tilt sensors are gravity/acceleration based and can provide accurate measurements of static responses. However, for dynamic tilt, acceleration can dramatically affect the measured responses due to crosstalk. Thus, dynamic tilt measurement is still a challenging problem. One option is to integrate the output of a gyroscope sensor, which measures the angular velocity, to obtain the tilt; however, problems arise because the low-frequency sensitivity of the gyroscope is poor. This paper proposes a new approach to dynamic tilt measurements, fusing together information from a MEMS-based gyroscope and an acceleration-based tilt sensor. The gyroscope provides good estimates of the tilt at higher frequencies, whereas the acceleration measurements are used to estimate the tilt at lower frequencies. The Tikhonov regularization approach is employed to fuse these measurements together and overcome the ill-posed nature of the problem. The solution is carried out in the frequency domain and then implemented in the time domain using FIR filters to ensure stability. The proposed method is validated numerically and experimentally to show that it performs well in estimating both the pseudo-static and dynamic tilt measurements.

  3. Analysis of the Gyroscopic Stabilization of a System of Rigid Bodies

    DEFF Research Database (Denmark)

    Kliem, Wolfhard; 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...

  4. Investigation of gyroscopic effects in vibrating fluid-filled cylinders subjected to axial rotation

    CSIR Research Space (South Africa)

    Shatalov, MY

    2007-07-01

    Full Text Available of the theory of gyroscopic effects in distributed structures. The model of a thick vibrating cylinder filled with a fluid and subjected to inertial rotation is analyzed. The dynamics of the cylinder is considered in terms of linear elasticity and the fluid...

  5. Wireless gyroscope platform enabled by a portable media device for quantifying wobble board therapy.

    Science.gov (United States)

    LeMoyne, Robert; Mastroianni, Timothy

    2017-07-01

    The wobble board enables a therapy strategy for rehabilitation of the ankle foot complex. Quantification of therapy, such as through the use of a wobble board, can facilitate a therapist's acuity for advancing and optimizing the overall therapy strategy. The portable media device, such as an iPod, can be equipped with a software application to function as a wireless gyroscope platform. Integration of the wobble board with the portable media device functioning as a wireless gyroscope enables the potential for patient to therapist interaction through connectivity to the Internet. A patient can conduct wobble board therapy for the ankle foot complex from the convenient vantage point of a homebound setting with therapy data transmitted wirelessly as email attachments. The gyroscope signal of the wobble board therapy can be consolidated into a feature set for machine learning classification. Using a multilayer perceptron neural network considerable classification accuracy has been achieved for differentiating between a hemiplegic affected ankle and unaffected ankle while using a wobble board. The combination of machine learning, wireless systems, such as a portable media device functioning as a wireless gyroscope, and a conventional therapy device, such as a wobble board, are envisioned to advance the capability to optimally impact the rehabilitation experience.

  6. Application of MEMS Accelerometers and Gyroscopes in Fast Steering Mirror Control Systems

    Directory of Open Access Journals (Sweden)

    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.

  7. Reflection-induced bias error in an air-core photonic bandgap fiber optic gyroscope.

    Science.gov (United States)

    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.

  8. Accelerometer and rate gyroscope measurement of kinematics: an inexpensive alternative to optical motion analysis systems

    NARCIS (Netherlands)

    Mayagoitia, R.E.; Mayagoitia, Ruth E.; Nene, A.V.; Veltink, Petrus 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

  9. Control of triceps surae stimulation based on shank orientation using a uniaxial gyroscope during gait

    NARCIS (Netherlands)

    Monaghan, C.C.; van Riel, W.J.B.M.; Veltink, Petrus 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

  10. GNSS Signal Tracking Performance Improvement for Highly Dynamic Receivers by Gyroscopic Mounting Crystal Oscillator.

    Science.gov (United States)

    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.

  11. GNSS Signal Tracking Performance Improvement for Highly Dynamic Receivers by Gyroscopic Mounting Crystal Oscillator

    Directory of Open Access Journals (Sweden)

    Maryam Abedi

    2015-08-01

    Full Text Available 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 (1σFLL. 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 (3σFLL. In this way, signal tracking performance can be improved by the gyroscopic mounting method for highly dynamic GNSS receivers.

  12. A universal gyroscope driving circuit with 70dB amplitude control range

    KAUST Repository

    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.

  13. Study on VCSEL laser heating chip in nuclear magnetic resonance gyroscope

    Science.gov (United States)

    Liang, Xiaoyang; Zhou, Binquan; Wu, Wenfeng; Jia, Yuchen; Wang, Jing

    2017-10-01

    In recent years, atomic gyroscope has become an important direction of inertial navigation. Nuclear magnetic resonance gyroscope has a stronger advantage in the miniaturization of the size. In atomic gyroscope, the lasers are indispensable devices which has an important effect on the improvement of the gyroscope performance. The frequency stability of the VCSEL lasers requires high precision control of temperature. However, the heating current of the laser will definitely bring in the magnetic field, and the sensitive device, alkali vapor cell, is very sensitive to the magnetic field, so that the metal pattern of the heating chip should be designed ingeniously to eliminate the magnetic field introduced by the heating current. In this paper, a heating chip was fabricated by MEMS process, i.e. depositing platinum on semiconductor substrates. Platinum has long been considered as a good resistance material used for measuring temperature The VCSEL laser chip is fixed in the center of the heating chip. The thermometer resistor measures the temperature of the heating chip, which can be considered as the same temperature of the VCSEL laser chip, by turning the temperature signal into voltage signal. The FPGA chip is used as a micro controller, and combined with PID control algorithm constitute a closed loop control circuit. The voltage applied to the heating resistor wire is modified to achieve the temperature control of the VCSEL laser. In this way, the laser frequency can be controlled stably and easily. Ultimately, the temperature stability can be achieved better than 100mK.

  14. A new cantilever beam-rigid-body MEMS gyroscope: mathematical model and linear dynamics

    CERN Document Server

    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.

  15. Measuring general relativity effects in a terrestrial lab by means of laser gyroscopes

    CERN Document Server

    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.

  16. Influence оf 2d Vibratory Motion Conveyed to Billet on Force And Timing Parameters of its Contact Interaction With Sawing Disc

    Directory of Open Access Journals (Sweden)

    M. G. Kiselev

    2014-01-01

    Full Text Available The paper presents an experimental investigation on influence of 2D vibratory dimension conveyed to a billet on force and timing parameters of its contact interaction with a sawing disc. Description of the modernized sawing section ensuring conveyance of 2D vibratory motion to a billet, methodology and  hardware facilities applied for normal force measurement of its impact with the disc and longevity of their contact for the period of the billet circulation motion. The paper provides, analyzes and generalizes experimentally obtained dependences reflecting influence of gap clearance between a boom and an upper stop on the mentioned force and timing parameters of the billet contact interaction with the sawing disc.

  17. Differences in joint-position sense and vibratory threshold in runners with and without a history of overuse injury.

    Science.gov (United States)

    Switlick, Tiffany; Kernozek, Thomas W; Meardon, Stacey

    2015-02-01

    A relationship between altered postural control and injury has been reported in sports. Sensorimotor function serves a fundamental role in postural control and is not often studied in runners. Persons who sustain running injury may have altered sensorimotor function contributing to risk of injury or reinjury. To determine if differences in knee and ankle proprioception or plantar sensation exist between injured and noninjured runners. Retrospective case-control study. University campus. Twenty runners with a history of lower-extremity overuse injury and 20 noninjured runners were examined. Injured runners were subcategorized into 2 groups based on site of injury: foot/ankle and knee/hip. Active absolute joint-repositioning error of the ankle at 20° inversion and 10° eversion and the knee at 15° and 40° flexion was assessed using an isokinetic dynamometer. Vibratory threshold at the calcaneus, arch, and great toe was determined for each subject using a handheld electric sensory threshold instrument. Runners in the injured-foot/ankle group had increased absolute error during ankle-eversion repositioning (6.55° ± 3.58°) compared with those in the noninjured (4.04° ± 1.78°, P = .01) and the hip/knee (3.63° ± 2.2°, P = .01) groups. Runners in the injured group, as a whole, had greater sensitivity in the arch of the plantar surface (2.94 ± 0.52 V) than noninjured runners (2.38 ± 0.53 V, P = .02). Differences in ankle-eversion proprioception between runners with a history of ankle and foot injuries and noninjured runners were observed. Runners with a history of injury also displayed an increased vibratory threshold in the arch region compared with noninjured runners. Poor ankle-joint-position sense and increased plantar sensitivity suggest altered sensorimotor function after injury. These factors may influence underlying postural control and contribute to altered loading responses commonly observed in injured runners.

  18. Low-frequency vibratory exercise reduces the risk of bone fracture more than walking: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Leal Alejo

    2006-11-01

    Full Text Available Abstract Background Whole-body vibration (WBV is a new type of exercise that has been increasingly tested for the ability to prevent bone fractures and osteoporosis in frail people. There are two currently marketed vibrating plates: a the whole plate oscillates up and down; b reciprocating vertical displacements on the left and right side of a fulcrum, increasing the lateral accelerations. A few studies have shown recently the effectiveness of the up-and-down plate for increasing Bone Mineral Density (BMD and balance; but the effectiveness of the reciprocating plate technique remains mainly unknown. The aim was to compare the effects of WBV using a reciprocating platform at frequencies lower than 20 Hz and a walking-based exercise programme on BMD and balance in post-menopausal women. Methods Twenty-eight physically untrained post-menopausal women were assigned at random to a WBV group or a Walking group. Both experimental programmes consisted of 3 sessions per week for 8 months. Each vibratory session included 6 bouts of 1 min (12.6 Hz in frequency and 3 cm in amplitude with 60° of knee flexion with 1 min rest between bouts. Each walking session was 55 minutes of walking and 5 minutes of stretching. Hip and lumbar BMD (g·cm-2 were measured using dual-energy X-ray absorptiometry and balance was assessed by the blind flamingo test. ANOVA for repeated measurements was adjusted by baseline data, weight and age. Results After 8 months, BMD at the femoral neck in the WBV group was increased by 4.3% (P = 0.011 compared to the Walking group. In contrast, the BMD at the lumbar spine was unaltered in both groups. Balance was improved in the WBV group (29% but not in the Walking group. Conclusion The 8-month course of vibratory exercise using a reciprocating plate is feasible and is more effective than walking to improve two major determinants of bone fractures: hip BMD and balance.

  19. Influence of the Radial Clearance of a Squeeze Film Damper on the Vibratory Behavior of a Single Spool Gas Turbine Designed for Unmanned Aerial Vehicle Applications

    OpenAIRE

    Geraldo Creci; José Orlando Balastrero; Sidney Domingues; Luis Vanderlei Torres; João Carlos Menezes

    2017-01-01

    This study presents a numerical investigation using the finite element method on the vibratory behavior of a single spool gas turbine designed for unmanned aerial vehicle applications. The shaft of the rotor-bearing system is supported on a front bearing composed of a deep groove ball bearing with a vibration absorber element and a rear squeeze film damper bearing. Three radial clearances for the squeeze film damper were analyzed to determine the best geometric configuration for the rear bear...

  20. Development of thin film encapsulation process for piezoresistive MEMS gyroscope with wide gaps

    Science.gov (United States)

    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

  1. Design and analysis of a dual-axis resonator fiber-optic gyroscope employing a single source.

    Science.gov (United States)

    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.

  2. Brillouin/Raman compensation of the Kerr-effect-induced bias in a nonlinear ring laser gyroscope.

    Science.gov (United States)

    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.

  3. Integrated Sagnac optical gyroscope sensor using ultra-low loss high aspect ratio silicon nitride waveguide coil

    Science.gov (United States)

    Gundavarapu, Sarat; Belt, Michael; Huffman, Taran; Tran, Minh A.; Komljenovic, Tin; Bowers, John E.; Blumenthal, Daniel J.

    2017-04-01

    We demonstrate operation of an interferometric optical gyroscope that uses an on-chip 3m ultra-low-loss silicon nitride waveguide coil. The measured minimum waveguide loss of the waveguide coil fabricated using lithographic die stitching was 0.78 dB/m. The angle random walk and bias instability of the gyroscope were characterized to be 8.52 deg/hr1/2 and 58.7 deg/hr respectively.

  4. The cosmological principles.

    Science.gov (United States)

    Rudnicki, K.

    The following topics were dealt with: the cosmological principles of Ancient India, Ancient Greece; the genuine Copernican and the generalized Copernican cosmological principles; the perfect, the anthropic and other cosmological principles; comparison of various cosmological principles; Goetheanism in science.

  5. Joint position sense and vibratory perception sense in patients with Ehlers-Danlos syndrome type III (hypermobility type).

    Science.gov (United States)

    Rombaut, Lies; De Paepe, Anne; Malfait, Fransiska; Cools, Ann; Calders, Patrick

    2010-03-01

    Neurophysiological deficits could make patients with Ehlers-Danlos syndrome (EDS) type III (hypermobility type) more vulnerable to musculoskeletal problems, particularly to joint instability. The purpose of this study was to investigate whether joint position sense (JPS) and vibratory perception sense (VPS) in EDS type III patients in the knee and shoulder joints are impaired. Thirty-two female EDS type III patients as defined by the Villefranche criteria and 32 individually gender- and age-matched healthy control subjects were included in the study. Range of motion was determined using a goniometer, passive and active JPS were assessed with an isokinetic dynamometer system, and the VPS was measured by a biothesiometer. Daily physical activity was evaluated by the Baecke questionnaire. The EDS type III group showed significantly larger ranges of movement (P physical activity (SPA) compared to the control group (P = 0.023). Considering SPA as covariate, the EDS type III group demonstrated a significant impairment in knee joint reposition compared to the control group (P = 0.018). No significant differences were found for shoulder JPS. The VPS was not significantly different in the EDS type III group compared to the control group. In addition, no significant correlation was found between JPS and VPS, neither at the knee nor at the shoulder joint. This is the first study examining proprioception deficits in EDS type III patients as defined by the Villefranche criteria. Further research on the neurophysiological dysfunctions and mechanisms in this pathologic entity is needed.

  6. Experimental Investigation on the Fatigue Life of Ti-6Al-4V Treated by Vibratory Stress Relief

    Directory of Open Access Journals (Sweden)

    Han-Jun Gao

    2017-05-01

    Full Text Available Vibratory stress relief (VSR is a highly efficient and low-energy consumption method to relieve and homogenize residual stresses in materials. Thus, the effect of VSR on the fatigue life should be determined. Standard fatigue specimens are fabricated to investigate the fatigue life of Ti-6Al-4V titanium alloy treated by VSR. The dynamic stresses generated under different VSR amplitudes are measured, and then the relationship between the dynamic stress and vibration amplitude is obtained. Different specimen groups are subjected to VSRs with different amplitudes and annealing treatment with typical process parameters. Residual stresses are measured to evaluate the stress relieving effects. Finally, the fatigue behavior under different states is determined by uniaxial tension–compression fatigue experiments. Results show that VSR and annealing treatment have negative effects on the fatigue life of Ti-6Al-4V. The fatigue life is decreased with the increase in VSR amplitude. When the VSR amplitude is less than 0.1 mm, the decrease in fatigue limit is less than 2%. Compared with specimens without VSR or annealing treatment, the fatigue limit of the specimens treated by VSR with 0.2 mm amplitude and annealing treatment decreases by 10.60% and 8.52%, respectively. Although the stress relieving effect is better, high amplitude VSR will lead to the decrease of Ti-6Al-4V fatigue life due to the defects generated during vibration. Low amplitude VSR can effectively relieve the stress with little decrease in fatigue life.

  7. Anesthetic block of the dorsal penile nerve inhibits vibratory-induced ejaculation in men with spinal cord injuries.

    Science.gov (United States)

    Wieder, J A; Brackett, N L; Lynne, C M; Green, J T; Aballa, T C

    2000-06-01

    [corrected] We investigated which nerve pathways are necessary to achieve ejaculation using penile vibratory stimulation (PVS) in men with spinal cord injury (SCI). Eight men with SCI were selected based on the presence of a bulbocavernosus reflex (BCR) and consistent antegrade ejaculation with PVS. Level of injury was cervical (4), upper thoracic (4), and lower thoracic (1). Mean age was 30.4 years (range 22 to 38). Usual responses to PVS included autonomic dysreflexia (4), erection (4), and consistent somatic responses such as abdominal contractions (8). Local anesthesia of the dorsal penile nerves (penile block) was achieved using 1% plain lidocaine injection. Effective penile block was confirmed by loss of the BCR. Two PVS ejaculation trials were performed: one trial during the penile block and one trial when the penile block had worn off. In 4 subjects, the bladder contents were analyzed for retrograde ejaculation. With the penile block, ejaculation was inhibited in 100% of the subjects. None of the bladder washings demonstrated sperm, indicating absence of retrograde ejaculation. None of the subjects exhibited their usual erectile response, somatic responses, or signs of autonomic dysreflexia. After the penile block wore off, PVS induced ejaculation in all subjects. If subjects usually had erection, somatic responses, or signs of autonomic dysreflexia, these also returned. Our data suggest that ejaculatory response to PVS in SCI men requires the presence of intact dorsal penile nerves.

  8. A single-ended CMOS sensing circuit for MEMS gyroscope with noise cancellation

    KAUST Repository

    Elsayed, Mohannad Yomn

    2010-06-01

    In this work, a complete single-ended readout circuit for capacitive MEMS gyroscope using chopper stabilization technique is presented. A novel noise cancellation technique is used to get rid of the bias noise. The circuit offers superior performance over state of the art readout circuits in terms of cost, gain, and noise for the given area and power consumption. The full circuit exhibits a gain of 58dB, a power dissipation of 1.3mW and an input referred noise of 12nV/√Hz. This would significantly improve the overall sensitivity of the gyroscope. The full circuit has been fabricated in 0.6um CMOS technology and it occupies an area of 0.4mm × 1mm. © 2010 IEEE.

  9. Deep underground rotation measurements: GINGERino ring laser gyroscope in Gran Sasso.

    Science.gov (United States)

    Belfi, Jacopo; Beverini, Nicolò; Bosi, Filippo; Carelli, Giorgio; Cuccato, Davide; De Luca, Gaetano; Di Virgilio, Angela; Gebauer, André; Maccioni, Enrico; Ortolan, Antonello; Porzio, Alberto; Saccorotti, Gilberto; Simonelli, Andreino; Terreni, Giuseppe

    2017-03-01

    GINGERino is a large frame laser gyroscope investigating the ground motion in the most inner part of the underground international laboratory of the Gran Sasso, in central Italy. It consists of a square ring laser with a 3.6 m side. Several days of continuous measurements have been collected, with the apparatus running unattended. The power spectral density in the seismic bandwidth is at the level of 10 -10  (rad/s)/Hz. A maximum resolution of 30 prad/s is obtained with an integration time of few hundred seconds. The ring laser routinely detects seismic rotations induced by both regional earthquakes and teleseisms. A broadband seismic station is installed on the same structure of the gyroscope. First analysis of the correlation between the rotational and the translational signal is presented.

  10. The validity of an assessment of maximum angular velocity of knee extension (KE) using a gyroscope.

    Science.gov (United States)

    Arai, Takeshi; Obuchi, Shuichi; Shiba, Yoshitaka; Omuro, Kazuya; Inaba, Yasuko; Kojima, Motonaga

    2012-01-01

    Although it is more important to assess the muscular power of the lower extremities than the strength, no simplified method for doing so has been found. The aim of this study was to assess the validity of the assessment of the angular velocity of KE using a gyroscope. Participants included 105 community-dwelling older people (55 women, 50 men, age ± standard deviation (SD) 75±5.3). Pearson correlation coefficients and Spearman rank-correlation coefficients were used to examine the relationships between the angular velocity of KE and functional performance measurements, a self-efficacy scale and health-related quality of life (HRQOL). The data from the gyroscope were significantly correlated with some physical functions such as muscle strength (r=0.304, pgyroscope could be a feasible and meaningful measurement in the geriatrics field. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  11. In-Orbit Performance Evaluation of a Spaceborne High Precision Fiber Optic Gyroscope.

    Science.gov (United States)

    Jin, Jing; Zhang, Ting; Kong, Linghai; Ma, Kun

    2018-01-01

    An in-orbit experiment was launched to evaluate the performance of the spaceborne high precision fiber optic gyroscopes (FOG). The three-axis in-orbit data of the FOG were analyzed using wavelet analysis method. Features of low frequency period terms and glitch noise were demonstrated. In addition, a method to extract the random noise from the in-orbit data is proposed based on the first-order difference method and the Pauta criterion. In addition, the random walk coefficient (RWC) of the FOG was calculated with the Allan variance method. Compared the ground test results, the in-orbit performance evaluation of Spaceborne High Precision Fiber Optic Gyroscope was verified.

  12. Calibration of atomic trajectories in a large-area dual-atom-interferometer gyroscope

    Science.gov (United States)

    Yao, Zhan-Wei; Lu, Si-Bin; Li, Run-Bing; Luo, Jun; Wang, Jin; Zhan, Ming-Sheng

    2018-01-01

    We propose and demonstrate a method for calibrating atomic trajectories in a large-area dual-atom-interferometer gyroscope. The atom trajectories are monitored by modulating and delaying the Raman transition, and they are precisely calibrated by controlling the laser orientation and the bias magnetic field. To improve the immunity to the gravity effect and the common phase noise, the symmetry and the overlap of two large-area atomic interference loops are optimized by calibrating the atomic trajectories and by aligning the Raman-laser orientations. The dual-atom-interferometer gyroscope is applied in the measurement of the Earth's rotation. The sensitivity is 1.2 ×10-6 rad s -1 Hz-1/2, and the long-term stability is 6.2 ×10-8 rad/s at 2000 s.

  13. Investigation of residual core ellipticity induced nonreciprocity in air-core photonic bandgap fiber optical gyroscope.

    Science.gov (United States)

    Xu, Xiaobin; Zhang, Zuchen; Zhang, Zhihao; Jin, Jing; Song, Ningfang

    2014-11-03

    Air-core photonic bandgap fiber (PBF) is an excellent choice for fiber optic gyroscope owing to its incomparable adaptability of environment. Strong and continuous polarization mode coupling is found in PBFs with an average intensity of ~-30 dB, but the coupling arrives at the limit when the maximum optical path difference between the primary waves and the polarization-mode-coupling-induced secondary waves reaches ~10mm, which is corresponding to the PBF length of ~110 m according to the birefringence in the PBF. Incident light with the low extinction ratio (ER) can suppress the birth of the polarization-mode-coupling-induced secondary waves, but the low-ER light obtained by the conventional Lyot depolarizers does not work here. Consequently, a large nonreciprocity and a bias error of ~13°/h are caused in the air-core photonic bandgap fiber optical gyroscope (PBFOG) with a PBF coil of ~268 m.

  14. Effect of external and internal magnetic fields on the bias stability in a Zeeman laser gyroscope

    Energy Technology Data Exchange (ETDEWEB)

    Kolbas, Yu Yu; Saveliev, I I; Khokhlov, N I [Open Joint-Stock Company M.F. Stel' makh Polyus Research Institute, Moscow (Russian Federation)

    2015-06-30

    With the specific features of electronic systems of a Zeeman laser gyroscope taken into account, the basic physical mechanisms of the magnetic field effect on the bias stability and the factors giving rise to the internal magnetic fields are revealed. The hardware-based methods of reducing the effect of external and internal magnetic fields are considered, as well as the algorithmic methods for increasing the stability of the bias magnetic component by taking into account its reproducible temperature and time dependences. Typical experimental temperature and time dependences of the magnetic component of the Zeeman laser gyro bias are presented, and by their example the efficiency of the proposed methods for reducing the effect of magnetic fields is shown. (laser gyroscopes)

  15. Automatic detection of EEG artefacts arising from head movements using EEG and gyroscope signals.

    Science.gov (United States)

    O'Regan, Simon; Faul, Stephen; Marnane, William

    2013-07-01

    Contamination of EEG signals by artefacts arising from head movements has been a serious obstacle in the deployment of automatic neurological event detection systems in ambulatory EEG. In this paper, we present work on categorizing these head-movement artefacts as one distinct class and on using support vector machines to automatically detect their presence. The use of additional physical signals in detecting head-movement artefacts is also investigated by means of support vector machines classifiers implemented with gyroscope waveforms. Finally, the combination of features extracted from EEG and gyroscope signals is explored in order to design an algorithm which incorporates both physical and physiological signals in accurately detecting artefacts arising from head-movements. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

  16. Application of the vector modulation method to the north finder capability gyroscope as a directional sensor

    Science.gov (United States)

    Celikel, Oguz

    2011-03-01

    This paper presents the application of the vector modulation method (VMM) to an open-loop interferometric fiber optic gyroscope, called the north finder capability gyroscope (NFCG), designed and assembled in TUBITAK UME (National Metrology Institute of Turkey). The method contains a secondary modulation/demodulation circuit with an AD630 chip, depending on the periodic variation of the orientation of the sensing coil sensitive surface vector with respect to geographic north at a laboratory latitude and collection of dc voltage at the secondary demodulation circuit output in the time domain. The resultant dc voltage proportional to the first-kind Bessel function based on Sagnac phase shift for the first order is obtained as a result of vector modulation together with the Earth's rotation. A new model function is developed and introduced to evaluate the angular errors of the NFCG with VMM in finding geographic north.

  17. Reproducibility of a 3-dimensional gyroscope in measuring shoulder anteflexion and abduction.

    Science.gov (United States)

    Penning, Ludo I F; Guldemond, Nick A; de Bie, Rob A; Walenkamp, Geert H I M

    2012-07-30

    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. 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. 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. 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 reproducibility of testing. The use of a tri axial gyroscope is a

  18. From space qualified fiber optic gyroscope to generic fiber optic solutions available for space application

    Science.gov (United States)

    Buret, Thomas; Ramecourt, David; Napolitano, Fabien

    2017-11-01

    The aim of this article is to present how the qualification of the Fiber Optic Gyroscope technology from IXSEA has been achieved through the qualification of a large range of optical devices and related manufacturing processes. These qualified optical devices and processes, that are now fully mastered by IXSEA through vertical integration of the technology, can be used for other space optical sensors. The example of the SWARM project will be discussed.

  19. Accelerometer and Magnetometer Based Gyroscope Emulation on Smart Sensor for a Virtual Reality Application

    Directory of Open Access Journals (Sweden)

    Baptiste Delporte

    2012-03-01

    Full Text Available In this paper, we propose two methods based on quaternions to compute the angles of inclination and the angular velocity with 6 degrees of freedom using the measurements of a 3-axis accelerometer and a 3-axis magnetometer. Each method has singularities which occur during the computation of the orientation of the device in the 3-dimensional space. We propose solutions to avoid these singularities. Experimental results are given to compare our model with a real gyroscope.

  20. Use of a gyroscope sensor to quantify tibial motions during a pivot shift test.

    Science.gov (United States)

    Borgstrom, Per Henrik; Markolf, Keith L; Foster, Brock; Petrigliano, Frank A; McAllister, David R

    2014-09-01

    The purpose of this preliminary study was to evaluate the use of a gyroscope sensor to record rotations of the tibia about its long axis during a clinical pivot shift examination. Ten patients with a unilateral ACL injury were tested under anaesthesia prior to surgery. Each ankle was placed in neutral position, wrapped and stabilized with athletic tape, and a small aluminium plate was taped to the bottom of the foot. A data recovery module was attached to the bottom of each plate using a swivel bracket that allowed alignment of the gyro axis with the long axis of the tibia. The module contained a triaxial gyroscope, battery and circuitry for wireless data broadcast to a laptop computer. Ten pivot shift tests were performed on both knees, and the surgeon's clinical grading of the pivot shift was noted for each limb. Mean values (10 trials) of peak tibial rotational velocity and integrated tibial rotation were compared between knees for each patient during the pivot shift reduction event (external tibial rotation during knee flexion). Five patients (50%) had significantly greater tibial rotation in their injured knee, four showed no difference between knees, and one had significantly greater rotation in the normal knee (p gyroscope measurements did not correctly identify the injured limb in all patients. Peak rotational velocity during the reduction event was a better indicator of ACL deficiency than the integrated rotation. If this technology is to be more useful clinically, gyroscope data may have to be combined with accelerometer data, perhaps with sensors mounted on both the tibia and femur. Diagnostic case-control study, Level III.

  1. State Derivation of a 12-Axis Gyroscope-Free Inertial Measurement Unit

    OpenAIRE

    Pei-Chun Lin; Jau-Ching Lu

    2011-01-01

    The derivation of linear acceleration, angular acceleration, and angular velocity states from a 12-axis gyroscope-free inertial measurement unit that utilizes four 3-axis accelerometer measurements at four distinct locations is reported. Particularly, a new algorithm which derives the angular velocity from its quadratic form and derivative form based on the context-based interacting multiple model is demonstrated. The performance of the system was evaluated under arbitrary 3-dimensional motion.

  2. State derivation of a 12-axis gyroscope-free inertial measurement unit.

    Science.gov (United States)

    Lu, Jau-Ching; Lin, Pei-Chun

    2011-01-01

    The derivation of linear acceleration, angular acceleration, and angular velocity states from a 12-axis gyroscope-free inertial measurement unit that utilizes four 3-axis accelerometer measurements at four distinct locations is reported. Particularly, a new algorithm which derives the angular velocity from its quadratic form and derivative form based on the context-based interacting multiple model is demonstrated. The performance of the system was evaluated under arbitrary 3-dimensional motion.

  3. Gyroscope precession along unbound equatorial plane orbits around a Kerr black hole

    CERN Document Server

    Bini, Donato; Jantzen, Robert T

    2016-01-01

    The precession of a test gyroscope along unbound equatorial plane geodesic orbits around a Kerr black hole is analyzed with respect to a static reference frame whose axes point towards the "fixed stars." The accumulated precession angle after a complete scattering process is evaluated and compared with the corresponding change in the orbital angle. Limiting results for the non-rotating Schwarzschild black hole case are also discussed.

  4. Eigenvalue analysis of a cantilever beam-rigid-body MEMS gyroscope

    CERN Document Server

    Lajimi, Seyed Amir Mousavi; Abdel-Rahman, Eihab

    2014-01-01

    The eigenvalues of a new microbeam-rigid-body gyroscope are computed and studied to show the variation of frequencies versus the input spin rate. To this end, assuming the harmonic solution of the dynamic equation of motion the characteristic equation is obtained and solved for the natural frequencies of the system in the rotating frame. It is shown that the difference between the natural frequencies (eigenvalues) proportionally grows with the input angular displacement rate.

  5. Gyroscope precession along bound equatorial plane orbits around a Kerr black hole

    CERN Document Server

    Bini, Donato; Jantzen, Robert T

    2016-01-01

    The precession of a test gyroscope along stable bound equatorial plane orbits around a Kerr black hole is analyzed and the precession angular velocity of the gyro's parallel transported spin vector and the increment in precession angle after one orbital period is evaluated. The parallel transported Marck frame which enters this discussion is shown to have an elegant geometrical explanation in terms of the electric and magnetic parts of the Killing-Yano 2-form and a Wigner rotation effect.

  6. Time- and Computation-Efficient Calibration of MEMS 3D Accelerometers and Gyroscopes

    Directory of Open Access Journals (Sweden)

    Sara Stančin

    2014-08-01

    Full Text Available We propose calibration methods for microelectromechanical system (MEMS 3D accelerometers and gyroscopes that are efficient in terms of time and computational complexity. The calibration process for both sensors is simple, does not require additional expensive equipment, and can be performed in the field before or between motion measurements. The methods rely on a small number of defined calibration measurements that are used to obtain the values of 12 calibration parameters. This process enables the static compensation of sensor inaccuracies. The values detected by the 3D sensor are interpreted using a generalized 3D sensor model. The model assumes that the values detected by the sensor are equal to the projections of the measured value on the sensor sensitivity axes. Although this finding is trivial for 3D accelerometers, its validity for 3D gyroscopes is not immediately apparent; thus, this paper elaborates on this latter topic. For an example sensor device, calibration parameters were established using calibration measurements of approximately 1.5 min in duration for the 3D accelerometer and 2.5 min in duration for the 3D gyroscope. Correction of each detected 3D value using the established calibration parameters in further measurements requires only nine addition and nine multiplication operations.

  7. Utility of the iPhone 4 Gyroscope Application in the Measurement of Wrist Motion.

    Science.gov (United States)

    Lendner, Nuphar; Wells, Erik; Lavi, Idit; Kwok, Yan Yan; Ho, Pak-Cheong; Wollstein, Ronit

    2017-09-01

    Measurement of wrist range of motion (ROM) is important to all aspects of treatment and rehabilitation of upper extremity conditions. Recently, gyroscopes have been used to measure ROM and may be more precise than manual evaluations. The purpose of this study was to evaluate the use of the iPhone gyroscope application and compare it with use of a goniometer, specifically evaluating its accuracy and ease of use. A cross-sectional study evaluated adult Caucasian participants, with no evidence of wrist pathology. Wrist ROM measurements in 306 wrists using the 2 methods were compared. Demographic information was collected including age, sex, and occupation. Analysis included mixed models and Bland-Altman plots. Wrist motion was similar between the 2 methods. Technical difficulties were encountered with gyroscope use. Age was an independent predictor of ROM. Correct measurement of ROM is critical to guide, compare, and evaluate treatment and rehabilitation of the upper extremity. Inaccurate measurements could mislead the surgeon and harm patient adherence with therapy or surgeon instruction. An application used by the patient could improve adherence but needs to be reliable and easy to use. Evaluation is necessary before utilization of such an application. This study supports revision of the application on the iPhone to improve ease of use.

  8. Implementation of a smartphone as a wireless gyroscope application for the quantification of reflex response.

    Science.gov (United States)

    LeMoyne, Robert; Mastroianni, Timothy

    2014-01-01

    The patellar tendon reflex constitutes a fundamental aspect of the conventional neurological evaluation. Dysfunctional characteristics of the reflex response can augment the diagnostic acuity of a clinician for subsequent referral to more advanced medical resources. The capacity to quantify the reflex response while alleviating the growing strain on specialized medical resources is a topic of interest. The quantification of the tendon reflex response has been successfully demonstrated with considerable accuracy and consistency through using a potential energy impact pendulum attached to a reflex hammer for evoking the tendon reflex with a smartphone, such as an iPhone, application representing a wireless accelerometer platform to quantify reflex response. Another sensor integrated into the smartphone, such as an iPhone, is the gyroscope, which measures rate of angular rotation. A smartphone application enables wireless transmission through Internet connectivity of the gyroscope signal recording of the reflex response as an email attachment. The smartphone wireless gyroscope application demonstrates considerable accuracy and consistency for the quantification of the tendon reflex response.

  9. Design of a full-dynamic-range balanced detection heterodyne gyroscope with common-path configuration.

    Science.gov (United States)

    Lin, Chu-En; Yu, Chih-Jen; Chen, Chii-Chang

    2013-04-22

    In this article, we propose an optical heterodyne common-path gyroscope which has common-path configuration and full-dynamic range. Different from traditional non-common-path optical heterodyne technique such as Mach-Zehnder or Michelson interferometers, we use a two-frequency laser light source (TFLS) which can generate two orthogonally polarized light with a beat frequency has a common-path configuration. By use of phase measurement, this optical heterodyne gyroscope not only has the capability to overcome the drawback of the traditional interferometric fiber optic gyro: lack for full-dynamic range, but also eliminate the total polarization rotation caused by SMFs. Moreover, we also demonstrate the potential of miniaturizing this gyroscope as a chip device. Theoretically, if we assume that the wavelength of the laser light is 1550nm, the SMFs are 250m in length, and the radius of the fiber ring is 3.5cm, the bias stability is 0.872 deg/hr.

  10. Gyroscope-reduced inertial navigation system for flight vehicle motion estimation

    Science.gov (United States)

    Wang, Xin; Xiao, Lu

    2017-01-01

    In this paper, a novel configuration of strategically distributed accelerometer sensors with the aid of one gyro to infer a flight vehicle's angular motion is presented. The MEMS accelerometer and gyro sensors are integrated to form a gyroscope-reduced inertial measurement unit (GR-IMU). The motivation for gyro aided accelerometers array is to have direct measurements of angular rates, which is an improvement to the traditional gyroscope-free inertial system that employs only direct measurements of specific force. Some technical issues regarding error calibration in accelerometers and gyro in GR-IMU are put forward. The GR-IMU based inertial navigation system can be used to find a complete attitude solution for flight vehicle motion estimation. Results of numerical simulation are given to illustrate the effectiveness of the proposed configuration. The gyroscope-reduced inertial navigation system based on distributed accelerometer sensors can be developed into a cost effective solution for a fast reaction, MEMS based motion capture system. Future work will include the aid from external navigation references (e.g. GPS) to improve long time mission performance.

  11. Operation of a high quality-factor gyroscope in electromechanical nonlinearities regime

    Science.gov (United States)

    Taheri-Tehrani, P.; Defoort, M.; Horsley, D. A.

    2017-07-01

    This paper describes the operation of a high quality factor gyroscope in various regimes where electromechanical nonlinearities introduce different forms of amplitude-frequency (A-f) dependence. Experiments are conducted using an epitaxially-encapsulated 2  ×  2 mm2 quad-mass gyroscope (QMG) with a quality factor of 85 000. The device exhibits third-order Duffing nonlinearity at low bias voltages (15 V) due to the mechanical nonlinearity in the flexures and at high bias voltages (35 V) due to third-order electrostatic nonlinearity. At intermediate voltages (~26 V), these third-order nonlinearities cancel and the amplitude-frequency dependence is greatly reduced. A model is developed to demonstrate the connection between the electromechanical nonlinearities and the amplitude-frequency dependence, also known as the backbone curve. Gyroscope operation is demonstrated in each nonlinear operating regime and the key performance measures of the gyroscope’s performance, angle random walk (ARW) and bias instability, are measured as a function of drive-mode vibration amplitude. We find that low ARW can be achieved even though the gyroscope’s drive mode exhibits large amplitude-frequency dependence, and that bias instability is largely independent of the operating regime.

  12. Coupling Mechanism Analysis and Fabrication of Triaxial Gyroscopes in Monolithic MIMU

    Directory of Open Access Journals (Sweden)

    Dunzhu Xia

    2017-10-01

    Full Text Available A novel fully decoupled micro inertial measurement unit (MIMU is presented in this paper. The proposed MIMU structure, mostly focusing on the gyroscope unit, is highly symmetrical and can be limited to an area of 10,000 μm × 10,000 μm. Both the tri-axis gyroscope and tri-axis accelerometer structures are fabricated on the same single silicon chip, which can differentially detect three axes’ angular velocities and linear accelerated velocities at the same time. By elaborately arranging different decoupling beams, anchors and sensing frames, the drive and sense modes of the tri-axis gyroscope are fully decoupled from each other. Several dynamic models, including decoupling beams with fabrication imperfections, are established for theoretical analysis. The numerical simulation made by MATLAB shows the structural decoupling of three sense modes, and indicates that the key decoupling beams, which affect the quadrature error, can be improved in design. The whole fabrication process, including silicon on glass (SOG process, dry/wet etching as well as the methods for improving the fabrication quality, is then shown. Experiments for mode frequency and quality factors of four modes (drive, yaw, pitch and roll have been performed, and are found to be 455 (6950.2 Hz, 66 (7054.4 Hz, 109 (7034.2 Hz and 107 (7040.5 Hz respectively. The analysis and experiment both prove that this novel MIMU has the potential value of further intensive investigation.

  13. Design and Implementation of Model Predictive Control for a Gyroscopic Inverted Pendulum

    Directory of Open Access Journals (Sweden)

    Trung-Dung Chu

    2017-12-01

    Full Text Available This study proposes the design of an active stabilizing system (ASAS for a single-track vehicle. Using the gyroscopic effects of two flywheels, this system can generate control torque to stabilize the vehicle in cases where there is centrifugal force of turning. To control the flywheel gimbals to generate stabilizing torque, a model predictive controller (MPC is applied to control the system. For the controller design and performance evaluations, a model of a gyroscopic inverted pendulum is developed. Control strategies are proposed to stabilize the vehicle in the cases of straight running, circular motion, and path following. The results of the proposed stratgies when controlling the gyroscopic inverted pendulum showed good performance even with physical limitations of the control torques. In order to evaluate the real-time performance and the feasibility of the MPC, a real-time simulator is employed, which includes two embedded STM32F407 boards. The dynamic system and the control algorithms are respectively embedded into two STM32F407 boards for real-time simulation. Implementations of the MPC in this study demonstrate that the proposed controllers are feasible for real-time applications.

  14. A Z-Axis Quartz Cross-Fork Micromachined Gyroscope Based on Shear Stress Detection

    Science.gov (United States)

    Xie, Liqiang; Wu, Xuezhong; Li, Shengyi; Wang, Haoxu; Su, Jianbin; Dong, Peitao

    2010-01-01

    Here we propose a novel quartz micromachined gyroscope. The sensor has a simple cross-fork structure in the x-y plane of quartz crystal. Shear stress rather than normal stress is utilized to sense Coriolis’ force generated by the input angular rate signal. Compared to traditional quartz gyroscopes, which have two separate sense electrodes on each sidewall, there is only one electrode on each sidewall of the sense beam. As a result, the fabrication of the electrodes is simplified and the structure can be easily miniaturized. In order to increase sensitivity, a pair of proof masses is attached to the ends of the drive beam, and the sense beam has a tapered design. The structure is etched from a z-cut quartz wafer and the electrodes are realized by direct evaporation using the aperture mask method. The drive mode frequency of the prototype is 13.38 kHz, and the quality factor is approximately 1,000 in air. Therefore, the gyroscope can work properly without a vacuum package. The measurement ability of the shear stress detection design scheme is validated by the Coriolis’ force test. The performance of the sensor is characterized on a precision rate table using a specially designed readout circuit. The experimentally obtained scale factor is 1.45 mV/°/s and the nonlinearity is 3.6% in range of ±200 °/s. PMID:22294887

  15. Perancangan Alat Ukur Sudut Tekuk Lutut Wireless menggunakan Sensor Gyroscope berbasis ATMega 328 dan ATMega 2560

    Directory of Open Access Journals (Sweden)

    TEGUH PERKASA

    2017-06-01

    Full Text Available ABSTRAKPada penelitian ini, sensor Gyroscope digunakan sebagai alat pengukur sudut lutut. Pengukuran sudut ini dilakukan untuk mendiagnosis penyakit pada pasien yang mengalami gangguan atau cedera lutut dan evaluasi pola jalan manusia. Alat pengukur sudut ini terdiri dari 3 sistem yaitu sistem tungkai bawah, sistem tungkai atas dan sistem komunikasi data. Media komunikasi data yang digunakan adalah radio frekuensi 2,4 GHz untuk mentransfer data sudut lutut antar sistem secara wireless. Sensor Gyroscope ditempelkan pada suatu divais mekanik berbahan acrylic sebagai representasi sistem tungkai kaki bawah dan sistem tungkai kaki atas. Kedua sensor tersebut digunakan untuk mengukur percepatan sudut dari kedua sistem tungkai kaki. Kemudian data tersebut diolah menjadi nilai sudut lutut menggunakan kontroler berbasis Arduino. Pengujian alat ini mencakup pengujian sistem tungkai bawah, sistem tungkai atas dan sistem komunikasi data. Dari hasil pengujian diperoleh nilai error sebesar 3 derajat untuk sistem tungkai bawah dan 2 derajat untuk sistem tungkai atas terhadap hasil pengukuran dengan goniometer yang biasa digunakan untuk mengukur sudut lutut oleh tenaga medis. Sistem komunikasi data wireless juga telah berhasil mengirimkan data sudut secara utuh.Kata Kunci: Arduino, Gyroscope, Radio Frekuensi, Sudut lutut, Wireless.ABSTRACTGyroscope sensor was used to measure a knee angle. The angle measurement is useful to diagnose an early symptom of some patient with disorders or knee injuries as well as to evaluation of gait analysis. The device consist of three system i.e. lower limb system, upper limb system and communication. The radio frequency of 2.4 GHz was used to transfer knee angle data between two systems. Gyroscope sensor were affixed on upper and lower part of the mechanical hinge device that built from acrylic. These device device was representative of the knee joint. Both sensors were used to measure the angular acceleration between the upper

  16. Signal processing of MEMS gyroscope arrays to improve accuracy using a 1st order Markov for rate signal modeling.

    Science.gov (United States)

    Jiang, Chengyu; Xue, Liang; Chang, Honglong; Yuan, Guangmin; Yuan, Weizheng

    2012-01-01

    This paper presents a signal processing technique to improve angular rate accuracy of the gyroscope by combining the outputs of an array of MEMS gyroscope. A mathematical model for the accuracy improvement was described and a Kalman filter (KF) was designed to obtain optimal rate estimates. Especially, the rate signal was modeled by a first-order Markov process instead of a random walk to improve overall performance. The accuracy of the combined rate signal and affecting factors were analyzed using a steady-state covariance. A system comprising a six-gyroscope array was developed to test the presented KF. Experimental tests proved that the presented model was effective at improving the gyroscope accuracy. The experimental results indicated that six identical gyroscopes with an ARW noise of 6.2 °/√h and a bias drift of 54.14 °/h could be combined into a rate signal with an ARW noise of 1.8 °/√h and a bias drift of 16.3 °/h, while the estimated rate signal by the random walk model has an ARW noise of 2.4 °/√h and a bias drift of 20.6 °/h. It revealed that both models could improve the angular rate accuracy and have a similar performance in static condition. In dynamic condition, the test results showed that the first-order Markov process model could reduce the dynamic errors 20% more than the random walk model.

  17. A piezoelectric gyroscope based on thickness-shear modes of an AlN bimorph with inclined c-axes

    Science.gov (United States)

    Cui, Jing; Du, Jianke; Wang, Ji; Yang, Jiashi

    2014-07-01

    We propose a new structure for piezoelectric gyroscope application. It consists of a two-layered plate of AlN with inclined c-axes. Through a theoretical analysis, it is shown that when the plate is electrically driven into thickness-shear (TSh) vibration in one direction and is rotating about the plate normal, the rotation causes a TSh vibration in a perpendicular direction with an electrical output which can be used to measure the angular rate of the rotation. Since AlN can be made into thin film devices much smaller than conventional crystal acoustic wave devices, the proposed gyroscope can be made much smaller than existing piezoelectric gyroscopes. The structure can also work with other crystals of class 6mm such as ZnO and polarized ceramics.

  18. A dynamic system matching technique for improving the accuracy of MEMS gyroscopes

    Energy Technology Data Exchange (ETDEWEB)

    Stubberud, Peter A., E-mail: stubber@ee.unlv.edu [Department of Electrical and Computer Engineering, University of Nevada, Las Vegas, Las Vegas, NV 89154 (United States); Stubberud, Stephen C., E-mail: scstubberud@ieee.org [Oakridge Technology, San Diego, CA 92121 (United States); Stubberud, Allen R., E-mail: stubberud@att.net [Department of Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA 92697 (United States)

    2014-12-10

    A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This can be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design

  19. Dynamics of test particles and pointlike gyroscopes in the brane world and other 5D models

    Science.gov (United States)

    Seahra, Sanjeev S.

    2002-06-01

    We study the dynamics of test particles and pointlike gyroscopes in 5D manifolds such as those used in the Randall-Sundrum brane world and noncompact Kaluza-Klein models. Our analysis is based on a covariant foliation of the manifold using (3+1)-dimensional spacetime slices orthogonal to the extra dimension, and is hence similar to the Arnowitt-Deser-Misner 3+1 split in ordinary general relativity. We derive gauge invariant equations of motion for freely falling test particles in the 5D and 4D affine parametrizations and contrast these results with previous work concerning the so-called ``fifth force.'' Motivated by the conjectured localization of matter fields on a 3-brane, we derive the form of the classical nongravitational force required to confine particles to a 4D hypersurface and show that the resulting trajectories are geometrically identical to the spacetime geodesics of Einstein's theory. We then discuss the issue of determining the 5D dynamics of a torque-free spinning body in the point-dipole approximation, and then perform a covariant (3+1)+1 decomposition of the relevant formulas (i.e., the 5D Fermi-Walker transport equation) for the cases of freely falling and hypersurface-confined point gyroscopes. In both cases, the 4D spin tensor is seen to be subject to an anomalous torque. We solve the spin equations for a gyroscope confined to a single spacetime section in a simple 5D cosmological model and observe a cosmological variation of the magnitude and orientation of the 4D spin.

  20. A dynamic system matching technique for improving the accuracy of MEMS gyroscopes

    Science.gov (United States)

    Stubberud, Peter A.; Stubberud, Stephen C.; Stubberud, Allen R.

    2014-12-01

    A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This can be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design tools for DSMT

  1. SCALE FACTOR DETERMINATION METHOD OF ELECTRO-OPTICAL MODULATOR IN FIBER-OPTIC GYROSCOPE

    Directory of Open Access Journals (Sweden)

    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 o​n 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.

  2. Handbook of force transducers. Principles and components

    Energy Technology Data Exchange (ETDEWEB)

    Stefanescu, Dan Mihai [Romanian Measurement Society, Bucharest (Romania)

    2011-07-01

    Part I introduces the basic ''Principles and Methods of Force Measurement'' according to a classification into a dozen of force transducers types: resistive, inductive, capacitive, piezoelectric, electromagnetic, electrodynamic, magnetoelastic, galvanomagnetic (Hall-effect), vibrating wires, (micro)resonators, acoustic and gyroscopic. Two special chapters refer to force balance techniques and to combined methods in force measurement. Part II discusses the ''(Strain Gauge) Force Transducers Components'', evolving from the classical force transducer to the digital / intelligent one, with the incorporation of three subsystems (sensors, electromechanics and informatics). The elastic element (EE) is the ''heart'' of the force transducer and basically determines its performance. A 12-type elastic element classification is proposed (stretched / compressed column or tube, bending beam, bending and/or torsion shaft, middle bent bar with fixed ends, shear beam, bending ring, yoke or frame, diaphragm, axial-stressed torus, axisymmetrical and voluminous EE), with emphasis on the optimum location of the strain gauges. The main properties of the associated Wheatstone bridge, best suited for the parametrical transducers, are examined, together with the appropriate electronic circuits for SGFTs. The handbook fills a gap in the field of Force Measurement, both experts and newcomers, no matter of their particular interest, finding a lot of useful and valuable subjects in the area of Force Transducers; in fact, it is the first specialized monograph in this inter- and multidisciplinary field. (orig.)

  3. The effect of broadened linewidth induced by dispersion on the performance of resonant optical gyroscope

    Science.gov (United States)

    Zhang, Hao; Li, Wenxiu; Han, Peng; Chang, Xiaoyang; Liu, Jiaming; Lin, Jian; Xue, Xia; Zhu, Fang; Yang, Yang; Liu, Xiaojing; Zhang, Xiaofu; Huang, Anping; Xiao, Zhisong; Fang, Jiancheng

    2018-01-01

    Anomalous dispersion enhancement physical mechanism for Sagnac effect is described by special relativity derivation, and three kinds of definitions of minimum detectable angular rate of resonance optical gyroscope (ROG) are compared and the relations among them are investigated. The effect of linewidth broadening induced by anomalous dispersion on the sensitivity of ROG is discussed in this paper. Material dispersion-broadened resonance linewidth deteriorates the performance of a passive ROG and dispersion enhancement effect, while the sensitivity of a structural dispersion ROG is enhanced by two orders of magnitude even considering the dispersion-broadened resonance linewidth.

  4. Establishment and analysis of coupled dynamic model for dual-mass silicon micro-gyroscope

    Science.gov (United States)

    Wang, Zhanghui; Qiu, Anping; Shi, Qin; Zhang, Taoyuan

    2017-12-01

    This paper presents a coupled dynamic model for a dual-mass silicon micro-gyroscope (DMSG). It can quantitatively analyze the influence of left-right stiffness difference on the natural frequencies, modal matrix and modal coupling coefficient of the DMSG. The analytic results are verified by using the finite element method (FEM) simulation. The model shows that with the left-right stiffness difference of 1%, the modal coupling coefficient is 12% in the driving direction and 31% in the sensing direction. It also shows that in order to achieve good separation, the stiffness of base beam should be small enough in both the driving and sensing direction.

  5. An improved temperature compensation circuit for SLD light source of fiber-optic gyroscope

    Science.gov (United States)

    Chen, Xian; Yang, Jianhua; Zhou, Yilan; Shu, Xiaowu

    2017-10-01

    The super luminescent diode light source is commonly used in Fiber-optic gyroscope. The wavelength temperature stability is one of its key parameters. In this work, simulation model of temperature field of the SLD light source is established, and the temperature distribution of SLD internal structure is simulated and researched. A temperature compensation scheme is designed according to the simulation result and experiment is done to confirm the specific parameter of compensation circuit. Then the designed compensation scheme is used in temperature control circuit of SLD, and the performance of compensated SLD light source is tested. An improvement of 62% is demonstrated compared with uncompensated SLD.

  6. Effective suppression of residual coherent phase error in a dual-polarization fiber optic gyroscope.

    Science.gov (United States)

    Luo, Rongya; Li, Yulin; Deng, Sheng; Peng, Chao; Li, Zhengbin

    2018-02-15

    The impact of residual coherent phase error in a dual-polarization interferometric fiber optic gyroscope (IFOG) is investigated. Although it has been intuitively assumed that the coherence of a light source can be eliminated by a sufficient long fiber delay, the experiment and theory indicate that it still contributes a remarkable portion to long-term instability. After the residual coherent phase error is well handled, we demonstrate a dual-polarization IFOG with bias instability of 3.56×10 -4 °/h. Comparisons show that such performance is even better than the conventional "minimal scheme" that operates on one polarization.

  7. Multiple-Point Temperature Gradient Algorithm for Ring Laser Gyroscope Bias Compensation.

    Science.gov (United States)

    Li, Geng; Zhang, Pengfei; Wei, Guo; Xie, Yuanping; Yu, Xudong; Long, Xingwu

    2015-11-30

    To further improve ring laser gyroscope (RLG) bias stability, a multiple-point temperature gradient algorithm is proposed for RLG bias compensation in this paper. Based on the multiple-point temperature measurement system, a complete thermo-image of the RLG block is developed. Combined with the multiple-point temperature gradients between different points of the RLG block, the particle swarm optimization algorithm is used to tune the support vector machine (SVM) parameters, and an optimized design for selecting the thermometer locations is also discussed. The experimental results validate the superiority of the introduced method and enhance the precision and generalizability in the RLG bias compensation model.

  8. Enhanced environmental performance of fiber optic gyroscope by an adhesive potting technology.

    Science.gov (United States)

    Chen, Jun; Ding, Nengwen; Li, Zhifeng; Wang, Wei

    2015-09-10

    An adhesive potting technology for fiber coils of a fiber optic gyroscope (FOG) is proposed. The fiber coil is immersed in liquid adhesive with superior mechanical properties. The internal air is first removed completely by vacuum pumping, and the adhesive is then evenly pressed into the fiber coil under pressure. The potted fiber core is prepared by ladder-type temperature curing and a stress-release process. With this potting technology, the vibration performance of an FOG is greatly improved and, at the same time, will not lead to degradation of its temperature performance. Using this potting technique of adhesive impregnation, the adaptability of FOGs will be enhanced.

  9. Design of a superluminal ring laser gyroscope using multilayer optical coatings with huge group delay.

    Science.gov (United States)

    Qu, Tianliang; Yang, Kaiyong; Han, Xiang; Wu, Suyong; Huang, Yun; Luo, Hui

    2014-11-18

    We propose and analyze a superluminal ring laser gyroscope (RLG) using multilayer optical coatings with huge group delay (GD). This GD assisted superluminal RLG can measure the absolute rotation with a giant sensitivity-enhancement factor of ~10(3); while, the broadband FWHM of the enhancement factor can reach 20 MHz. This superluminal RLG is based on a traditional RLG with minimal re-engineering, and beneficial for miniaturization according to theoretical calculation. The idea of using GD coatings as a fast-light medium will shed lights on the design and application of fast-light sensors.

  10. Drift suppression in a dual-polarization fiber optic gyroscope caused by the Faraday effect

    Science.gov (United States)

    Liu, Pan; Li, Xuyou; Guang, Xingxing; Xu, Zhenlong; Ling, Weiwei; Yang, Hanrui

    2017-07-01

    An investigation of the drift caused by the Faraday effect in a dual-polarization interferometric fiber optic gyroscope (IFOG) is presented. Both theoretical analysis and experimental results indicate that the Faraday effect phase drifts in two orthogonal polarizations of polarization-maintaining fiber always have opposite polarities that can be compensated effectively. When the interference signals of the two orthogonal polarized light waves are added up, the bias stability of the IFOG is improved significantly. This study is promising for reducing the drift of IFOG caused by the Faraday effect.

  11. Dynamics of the Gyroscopic Power Take-Off Wave Energy Absorber in Irregular Sea States

    DEFF Research Database (Denmark)

    Zhang, Zili; Nielsen, Søren R. K.; Olsen, Jan

    2017-01-01

    Dynamic modelling and analysis of a newly proposed wave energy point absorber, the Gyroscopic power take-off (GyroPTO) absorber, is presented in this study. Inside the float of the GyroPTO, there is a mechanical system made up of a spinning flywheel with its spin axis in rolling contact to a ring....... Linear wave theory has been applied together with rational approximation of the radiation damping moments, leading to an extended state vector formulation of the coupled structure- wave system. Simulation results show that magnetic coupling successfully improves the stability of the flywheel in irregular...

  12. An Alignment Fixture for a Two-Degree-of-Freedom (TDF) Gyroscope.

    Science.gov (United States)

    1984-06-01

    range of + 100 was purchased (Fig. 6). The tip and tilt action of the gyroscope controlled by two micrometers each linked to the moveable tip and tilt...W027 0 S 6 6 S rotation stages type TR 0 - origin of the vernier 50 ’ (reading 1/60) VIEW FROM BOTTOM FACE 4 tapped noles oV. (ISO) (DP B K Neck 1T...and allow tip/tilt. The tip and tilt motions are adjusted, the amount of angles mea- sured by micrometers . The micrometers are each linked to the

  13. Minimal-Learning-Parameter Technique Based Adaptive Neural Sliding Mode Control of MEMS Gyroscope

    Directory of Open Access Journals (Sweden)

    Bin Xu

    2017-01-01

    Full Text Available This paper investigates an adaptive neural sliding mode controller for MEMS gyroscopes with minimal-learning-parameter technique. Considering the system uncertainty in dynamics, neural network is employed for approximation. Minimal-learning-parameter technique is constructed to decrease the number of update parameters, and in this way the computation burden is greatly reduced. Sliding mode control is designed to cancel the effect of time-varying disturbance. The closed-loop stability analysis is established via Lyapunov approach. Simulation results are presented to demonstrate the effectiveness of the method.

  14. A novel Cs-(129)Xe atomic spin gyroscope with closed-loop Faraday modulation.

    Science.gov (United States)

    Fang, Jiancheng; Wan, Shuangai; Qin, Jie; Zhang, Chen; Quan, Wei; Yuan, Heng; Dong, Haifeng

    2013-08-01

    We report a novel Cs-(129)Xe atomic spin gyroscope (ASG) with closed-loop Faraday modulation method. This ASG requires approximately 30 min to start-up and 110 °C to operate. A closed-loop Faraday modulation method for measurement of the optical rotation was used in this ASG. This method uses an additional Faraday modulator to suppress the laser intensity fluctuation and Faraday modulator thermal induced fluctuation. We theoretically and experimentally validate this method in the Cs-(129)Xe ASG and achieved a bias stability of approximately 3.25 °∕h.

  15. Influence of the Radial Clearance of a Squeeze Film Damper on the Vibratory Behavior of a Single Spool Gas Turbine Designed for Unmanned Aerial Vehicle Applications

    Directory of Open Access Journals (Sweden)

    Geraldo Creci

    2017-01-01

    Full Text Available This study presents a numerical investigation using the finite element method on the vibratory behavior of a single spool gas turbine designed for unmanned aerial vehicle applications. The shaft of the rotor-bearing system is supported on a front bearing composed of a deep groove ball bearing with a vibration absorber element and a rear squeeze film damper bearing. Three radial clearances for the squeeze film damper were analyzed to determine the best geometric configuration for the rear bearing, considering the rotordynamic performance of the entire system. Whirl speeds and unbalanced system responses were carefully evaluated to determine the best radial clearance for the squeeze film damper. After defining the best radial clearance, a transient analysis was performed to simulate the transition of the system through resonance, and a spectral map is presented to illustrate the vibratory behavior of the system considering the influence of all related important frequencies. The rotordynamic behavior of the system is predicted, and vibration problems are avoided. Its mechanical drawings were released to manufacturing, and the first prototype is in the experimental test phase, thus indicating that the numerical results presented in this study are consistent.

  16. Obtention of hydroxyapatite submicrometric of bovine origin by vibratory grinding for rapid prototyping; Obtencao de hidroxiapatita submicrometrica de origem bovina por moagem vibratoria visando prototipagem rapida

    Energy Technology Data Exchange (ETDEWEB)

    Meira, C.R.; Purquerio, B.M.; Fortulan, C.A., E-mail: camilameira@sc.usp.br [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Escola de Engenharia; Braga, F.J.C. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Submicron bovine hydroxyapatite was obtained for rapid prototyping. Hydroxyapatite structure originated from bovine mineral bone has great importance among the biomaterials and biocompatibility due to its great similarity with the human bone structure. This study aims to obtain powder for manufacture by rapid prototyping of scaffolds. This technique manufacture requires highly reactive powders to compensate for the absence of pressure forming. Hydroxyapatite was milled in a ball mill and vibratory mill, and analyzed for their average equivalent spherical diameter and surface area. Test specimens were isostatically pressed at 100 MPa and machined into cylindrical test specimens. These specimens were sintered at several temperatures to determine the optimal sintering temperature based on densification and chemistry stability. In grinding ball mill was obtained particles of equivalent diameter of 0.74 micron in vibratory mill of 0.46 micrometers. An average flexural strength of 100 MPa and 99,8% of real density was attained for the sample sintered at 1300 deg C/2h, signaling potential for use in rapid prototyping. (author)

  17. Angle Estimation of Simultaneous Orthogonal Rotations from 3D Gyroscope Measurements

    Directory of Open Access Journals (Sweden)

    Sara Stančin

    2011-09-01

    Full Text Available A 3D gyroscope provides measurements of angular velocities around its three intrinsic orthogonal axes, enabling angular orientation estimation. Because the measured angular velocities represent simultaneous rotations, it is not appropriate to consider them sequentially. Rotations in general are not commutative, and each possible rotation sequence has a different resulting angular orientation. None of these angular orientations is the correct simultaneous rotation result. However, every angular orientation can be represented by a single rotation. This paper presents an analytic derivation of the axis and angle of the single rotation equivalent to three simultaneous rotations around orthogonal axes when the measured angular velocities or their proportions are approximately constant. Based on the resulting expressions, a vector called the simultaneous orthogonal rotations angle (SORA is defined, with components equal to the angles of three simultaneous rotations around coordinate system axes. The orientation and magnitude of this vector are equal to the equivalent single rotation axis and angle, respectively. As long as the orientation of the actual rotation axis is constant, given the SORA, the angular orientation of a rigid body can be calculated in a single step, thus making it possible to avoid computing the iterative infinitesimal rotation approximation. The performed test measurements confirm the validity of the SORA concept. SORA is simple and well-suited for use in the real-time calculation of angular orientation based on angular velocity measurements derived using a gyroscope. Moreover, because of its demonstrated simplicity, SORA can also be used in general angular orientation notation.

  18. Gait Detection in Children with and without Hemiplegia Using Single-Axis Wearable Gyroscopes

    Science.gov (United States)

    Abaid, Nicole; Cappa, Paolo; Palermo, Eduardo; Petrarca, Maurizio; Porfiri, Maurizio

    2013-01-01

    In this work, we develop a novel gait phase detection algorithm based on a hidden Markov model, which uses data from foot-mounted single-axis gyroscopes as input. We explore whether the proposed gait detection algorithm can generate equivalent results as a reference signal provided by force sensitive resistors (FSRs) for typically developing children (TD) and children with hemiplegia (HC). We find that the algorithm faithfully reproduces reference results in terms of high values of sensitivity and specificity with respect to FSR signals. In addition, the algorithm distinguishes between TD and HC and is able to assess the level of gait ability in patients. Finally, we show that the algorithm can be adapted to enable real-time processing with high accuracy. Due to the small, inexpensive nature of gyroscopes utilized in this study and the ease of implementation of the developed algorithm, this work finds application in the on-going development of active orthoses designed for therapy and locomotion in children with gait pathologies. PMID:24023825

  19. Gait detection in children with and without hemiplegia using single-axis wearable gyroscopes.

    Directory of Open Access Journals (Sweden)

    Nicole Abaid

    Full Text Available In this work, we develop a novel gait phase detection algorithm based on a hidden Markov model, which uses data from foot-mounted single-axis gyroscopes as input. We explore whether the proposed gait detection algorithm can generate equivalent results as a reference signal provided by force sensitive resistors (FSRs for typically developing children (TD and children with hemiplegia (HC. We find that the algorithm faithfully reproduces reference results in terms of high values of sensitivity and specificity with respect to FSR signals. In addition, the algorithm distinguishes between TD and HC and is able to assess the level of gait ability in patients. Finally, we show that the algorithm can be adapted to enable real-time processing with high accuracy. Due to the small, inexpensive nature of gyroscopes utilized in this study and the ease of implementation of the developed algorithm, this work finds application in the on-going development of active orthoses designed for therapy and locomotion in children with gait pathologies.

  20. How Angular Velocity Features and Different Gyroscope Noise Types Interact and Determine Orientation Estimation Accuracy.

    Science.gov (United States)

    Pasciuto, Ilaria; Ligorio, Gabriele; Bergamini, Elena; Vannozzi, Giuseppe; Sabatini, Angelo Maria; Cappozzo, Aurelio

    2015-09-18

    In human movement analysis, 3D body segment orientation can be obtained through the numerical integration of gyroscope signals. These signals, however, are affected by errors that, for the case of micro-electro-mechanical systems, are mainly due to: constant bias, scale factor, white noise, and bias instability. The aim of this study is to assess how the orientation estimation accuracy is affected by each of these disturbances, and whether it is influenced by the angular velocity magnitude and 3D distribution across the gyroscope axes. Reference angular velocity signals, either constant or representative of human walking, were corrupted with each of the four noise types within a simulation framework. The magnitude of the angular velocity affected the error in the orientation estimation due to each noise type, except for the white noise. Additionally, the error caused by the constant bias was also influenced by the angular velocity 3D distribution. As the orientation error depends not only on the noise itself but also on the signal it is applied to, different sensor placements could enhance or mitigate the error due to each disturbance, and special attention must be paid in providing and interpreting measures of accuracy for orientation estimation algorithms.

  1. Accelerometer and gyroscope based gait analysis using spectral analysis of patients with osteoarthritis of the knee.

    Science.gov (United States)

    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.

  2. Simulations of the Flow in the Liquid Floating Micro-gyroscope

    Science.gov (United States)

    Tang, Fei; Wang, Chun Ze; Li, Qi; Wang, Xiao Hao

    2017-11-01

    The interactions between the centrifugal force, the cavity and the scale effect make the flow become complicated when the rotor of liquid floating micro-gyroscope rotates in a confined space at a high speed. In this paper, The Reynolds averaged equations were solved with simulation and the distribution laws of the mean flow, turbulent statics and drag were obtained in different Reynolds numbers and aspect ratios of the cavity. The circumferential velocities along z direction changed from linearity to nonlinearity with the increasing of Reynolds number, corresponding to torsional Couette flow To Batchelor flow. The radial velocities kept S shape with different maximum value and the axial velocities were nearly zeros except very close to the inner and the outer cylinders. For Reynolds stresses, they were concentrated in the vicinity of the boundary layer and the normal stresses were slightly higher than shear stresses. The drag coefficients increased with the increasing of the Reynolds number. But the growth rates were not the same in different parameters. This paper provides a guidance for the manufacture of the liquid floating micro-gyroscope.

  3. Angle estimation of simultaneous orthogonal rotations from 3D gyroscope measurements.

    Science.gov (United States)

    Stančin, Sara; Tomažič, Sašo

    2011-01-01

    A 3D gyroscope provides measurements of angular velocities around its three intrinsic orthogonal axes, enabling angular orientation estimation. Because the measured angular velocities represent simultaneous rotations, it is not appropriate to consider them sequentially. Rotations in general are not commutative, and each possible rotation sequence has a different resulting angular orientation. None of these angular orientations is the correct simultaneous rotation result. However, every angular orientation can be represented by a single rotation. This paper presents an analytic derivation of the axis and angle of the single rotation equivalent to three simultaneous rotations around orthogonal axes when the measured angular velocities or their proportions are approximately constant. Based on the resulting expressions, a vector called the simultaneous orthogonal rotations angle (SORA) is defined, with components equal to the angles of three simultaneous rotations around coordinate system axes. The orientation and magnitude of this vector are equal to the equivalent single rotation axis and angle, respectively. As long as the orientation of the actual rotation axis is constant, given the SORA, the angular orientation of a rigid body can be calculated in a single step, thus making it possible to avoid computing the iterative infinitesimal rotation approximation. The performed test measurements confirm the validity of the SORA concept. SORA is simple and well-suited for use in the real-time calculation of angular orientation based on angular velocity measurements derived using a gyroscope. Moreover, because of its demonstrated simplicity, SORA can also be used in general angular orientation notation.

  4. How Angular Velocity Features and Different Gyroscope Noise Types Interact and Determine Orientation Estimation Accuracy

    Directory of Open Access Journals (Sweden)

    Ilaria Pasciuto

    2015-09-01

    Full Text Available In human movement analysis, 3D body segment orientation can be obtained through the numerical integration of gyroscope signals. These signals, however, are affected by errors that, for the case of micro-electro-mechanical systems, are mainly due to: constant bias, scale factor, white noise, and bias instability. The aim of this study is to assess how the orientation estimation accuracy is affected by each of these disturbances, and whether it is influenced by the angular velocity magnitude and 3D distribution across the gyroscope axes. Reference angular velocity signals, either constant or representative of human walking, were corrupted with each of the four noise types within a simulation framework. The magnitude of the angular velocity affected the error in the orientation estimation due to each noise type, except for the white noise. Additionally, the error caused by the constant bias was also influenced by the angular velocity 3D distribution. As the orientation error depends not only on the noise itself but also on the signal it is applied to, different sensor placements could enhance or mitigate the error due to each disturbance, and special attention must be paid in providing and interpreting measures of accuracy for orientation estimation algorithms.

  5. Use of Earth’s Magnetic Field for Mitigating Gyroscope Errors Regardless of Magnetic Perturbation

    Science.gov (United States)

    Afzal, Muhammad Haris; Renaudin, Valérie; Lachapelle, Gérard

    2011-01-01

    Most portable systems like smart-phones are equipped with low cost consumer grade sensors, making them useful as Pedestrian Navigation Systems (PNS). Measurements of these sensors are severely contaminated by errors caused due to instrumentation and environmental issues rendering the unaided navigation solution with these sensors of limited use. The overall navigation error budget associated with pedestrian navigation can be categorized into position/displacement errors and attitude/orientation errors. Most of the research is conducted for tackling and reducing the displacement errors, which either utilize Pedestrian Dead Reckoning (PDR) or special constraints like Zero velocity UPdaTes (ZUPT) and Zero Angular Rate Updates (ZARU). This article targets the orientation/attitude errors encountered in pedestrian navigation and develops a novel sensor fusion technique to utilize the Earth’s magnetic field, even perturbed, for attitude and rate gyroscope error estimation in pedestrian navigation environments where it is assumed that Global Navigation Satellite System (GNSS) navigation is denied. As the Earth’s magnetic field undergoes severe degradations in pedestrian navigation environments, a novel Quasi-Static magnetic Field (QSF) based attitude and angular rate error estimation technique is developed to effectively use magnetic measurements in highly perturbed environments. The QSF scheme is then used for generating the desired measurements for the proposed Extended Kalman Filter (EKF) based attitude estimator. Results indicate that the QSF measurements are capable of effectively estimating attitude and gyroscope errors, reducing the overall navigation error budget by over 80% in urban canyon environment. PMID:22247672

  6. Multi-scale analysis on nonlinear gyroscopic systems with multi-degree-of-freedoms

    Science.gov (United States)

    Chen, Li-Qun; Zhang, Yan-Lei

    2014-09-01

    A method of multiple scales is developed for n-degree-of-freedom weakly nonlinear gyroscopic systems. A general procedure is proposed to establish solvability conditions. The conditions have n different versions whose equivalence cannot be mathematically demonstrated. The procedure is applied to a 4-degree-of-freedom nonlinear gyroscopic system that is the 4-term Galerkin truncation of the governing equation of a pipe conveying fluid flowing in the supercritical speed. The investigation focuses on the primary external resonance in the first frequency ω1 and the two-to-one internal resonance of the first two frequencies ω1 and ω2. The multi-scale analysis shows that the amplitude-frequency response curve in each of the first two modes has a peak bending to the left when ω2>2ω1, two peaks with the same height and the opposite bending directions when ω2=2ω1, and a peak bending to the right when ω2<2ω1. In all those cases, the 4 different versions of the solvability conditions yield same outcomes. The responses in the last two modes uninvolved in the resonances decay to zero exponentially. The numerical integration results are qualitative agreement with the analytical ones.

  7. Comparative research on the methods for measuring the mode deflection angle of cylindrical resonator gyroscope

    Science.gov (United States)

    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.

  8. Self-induced parametric amplification arising from nonlinear elastic coupling in a micromechanical resonating disk gyroscope

    Science.gov (United States)

    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. PMID:25762243

  9. Analysis of dead zone sources in a closed-loop fiber optic gyroscope.

    Science.gov (United States)

    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.

  10. A new twist on gyroscopic sensing: body rotations lead to torsion in flapping, flexing insect wings.

    Science.gov (United States)

    Eberle, A L; Dickerson, B H; Reinhall, P G; Daniel, T L

    2015-03-06

    Insects perform fast rotational manoeuvres during flight. While two insect orders use flapping halteres (specialized organs evolved from wings) to detect body dynamics, it is unknown how other insects detect rotational motions. Like halteres, insect wings experience gyroscopic forces when they are flapped and rotated and recent evidence suggests that wings might indeed mediate reflexes to body rotations. But, can gyroscopic forces be detected using only changes in the structural dynamics of a flapping, flexing insect wing? We built computational and robotic models to rotate a flapping wing about an axis orthogonal to flapping. We recorded high-speed video of the model wing, which had a flexural stiffness similar to the wing of the Manduca sexta hawkmoth, while flapping it at the wingbeat frequency of Manduca (25 Hz). We compared the three-dimensional structural dynamics of the wing with and without a 3 Hz, 10° rotation about the yaw axis. Our computational model revealed that body rotation induces a new dynamic mode: torsion. We verified our result by measuring wing tip displacement, shear strain and normal strain of the robotic wing. The strains we observed could stimulate an insect's mechanoreceptors and trigger reflexive responses to body rotations. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  11. Characterization of membrane curvature in micromachined silicon accelerometers and gyroscopes using optical interferometry

    Science.gov (United States)

    Borenstein, Jeffrey T.; Greiff, Paul; Sohn, Jerome B.; Weinberg, Marc S.

    1996-09-01

    Micromachined silicon sensors often exhibit curvature of released membrane structures due to internal stresses, doping gradients, and crystalline defects. This curvature can be a significant source of error in inertial sensors such as accelerometers and gyroscopes. Development of process conditions that reduce curl requires a rapid, accurate method for obtaining high-resolution flatness data over a complex two-dimensional surface. This work reports on the use of a commercially-available, nondestructive optical characterization tool that provides high-resolution profiles of micromachined structures. This interferometry technique is shown to be a significant extension of traditional process development tools, such as scanning electron microscopy (SEM) and test structures. Statistical information on flatness of test structures, accelerometers, and gyroscopes is reported as a function of processing conditions. Unexpected and previously undetected phenomena are revealed by the interferometry measurement. Optimization of the diffusion-annealing cycle provides structures that are flat to within 0.1 micrometers. The flatter parts now being produced have contributed to recent advances in the performance of Draper Laboratory's inertial sensors.

  12. Modeling and Compensation of Random Drift of MEMS Gyroscopes Based on Least Squares Support Vector Machine Optimized by Chaotic Particle Swarm Optimization.

    Science.gov (United States)

    Xing, Haifeng; Hou, Bo; Lin, Zhihui; Guo, Meifeng

    2017-10-13

    MEMS (Micro Electro Mechanical System) gyroscopes have been widely applied to various fields, but MEMS gyroscope random drift has nonlinear and non-stationary characteristics. It has attracted much attention to model and compensate the random drift because it can improve the precision of inertial devices. This paper has proposed to use wavelet filtering to reduce noise in the original data of MEMS gyroscopes, then reconstruct the random drift data with PSR (phase space reconstruction), and establish the model for the reconstructed data by LSSVM (least squares support vector machine), of which the parameters were optimized using CPSO (chaotic particle swarm optimization). Comparing the effect of modeling the MEMS gyroscope random drift with BP-ANN (back propagation artificial neural network) and the proposed method, the results showed that the latter had a better prediction accuracy. Using the compensation of three groups of MEMS gyroscope random drift data, the standard deviation of three groups of experimental data dropped from 0.00354°/s, 0.00412°/s, and 0.00328°/s to 0.00065°/s, 0.00072°/s and 0.00061°/s, respectively, which demonstrated that the proposed method can reduce the influence of MEMS gyroscope random drift and verified the effectiveness of this method for modeling MEMS gyroscope random drift.

  13. On Steady Motions of a Rigid Body Bearing Three-Degree-of-Freedom Control Momentum Gyroscopes and Their Stability

    NARCIS (Netherlands)

    Amel'kin, N. I.

    Equations of motion are obtained for a rigid body bearing N three-degree-of-freedom control momentum gyroscopes in gimbals and the entire set of steady motions in a homogeneous external field is determined. The steady motion dependence on the magnitude of the system angular momentum is studied and a

  14. A Lever Coupling Mechanism in Dual-Mass Micro-Gyroscopes for Improving the Shock Resistance along the Driving Direction

    Directory of Open Access Journals (Sweden)

    Yang Gao

    2017-04-01

    Full Text Available This paper presents the design and application of a lever coupling mechanism to improve the shock resistance of a dual-mass silicon micro-gyroscope with drive mode coupled along the driving direction without sacrificing the mechanical sensitivity. Firstly, the mechanical sensitivity and the shock response of the micro-gyroscope are theoretically analyzed. In the mechanical design, a novel lever coupling mechanism is proposed to change the modal order and to improve the frequency separation. The micro-gyroscope with the lever coupling mechanism optimizes the drive mode order, increasing the in-phase mode frequency to be much larger than the anti-phase one. Shock analysis results show that the micro-gyroscope structure with the designed lever coupling mechanism can notably reduce the magnitudes of the shock response and cut down the stress produced in the shock process compared with the traditional elastic coupled one. Simulations reveal that the shock resistance along the drive direction is greatly increased. Consequently, the lever coupling mechanism can change the gyroscope’s modal order and improve the frequency separation by structurally offering a higher stiffness difference ratio. The shock resistance along the driving direction is tremendously enhanced without loss of the mechanical sensitivity.

  15. Analysis of nonlinear dynamics of a cantilever beam-rigid-body MEMS gyroscope using a continuation method

    CERN Document Server

    Lajimi, Seyed Amir Mousavi

    2014-01-01

    The nonlinear dynamics of a microbeam-rigid body gyroscope are investigated by using a continuation method. To study the nonlinear dynamics of the system, the Lagrangian of the system is discretized and the reduced-order model is obtained. By using the continuation method, the frequency-response curves are computed and the stability of response is determined.

  16. A Lever Coupling Mechanism in Dual-Mass Micro-Gyroscopes for Improving the Shock Resistance along the Driving Direction

    Science.gov (United States)

    Gao, Yang; Li, Hongsheng; Huang, Libin; Sun, Hui

    2017-01-01

    This paper presents the design and application of a lever coupling mechanism to improve the shock resistance of a dual-mass silicon micro-gyroscope with drive mode coupled along the driving direction without sacrificing the mechanical sensitivity. Firstly, the mechanical sensitivity and the shock response of the micro-gyroscope are theoretically analyzed. In the mechanical design, a novel lever coupling mechanism is proposed to change the modal order and to improve the frequency separation. The micro-gyroscope with the lever coupling mechanism optimizes the drive mode order, increasing the in-phase mode frequency to be much larger than the anti-phase one. Shock analysis results show that the micro-gyroscope structure with the designed lever coupling mechanism can notably reduce the magnitudes of the shock response and cut down the stress produced in the shock process compared with the traditional elastic coupled one. Simulations reveal that the shock resistance along the drive direction is greatly increased. Consequently, the lever coupling mechanism can change the gyroscope’s modal order and improve the frequency separation by structurally offering a higher stiffness difference ratio. The shock resistance along the driving direction is tremendously enhanced without loss of the mechanical sensitivity. PMID:28468288

  17. Atom Interferometer Gyroscope with Spin-Dependent Phase Shifts Induced by Light near a Tune-Out Wavelength

    CERN Document Server

    Trubko, Raisa; Germaine, Michael T St; Gregoire, Maxwell D; Holmgren, William F; Hromada, Ivan; Cronin, Alexander D

    2015-01-01

    Tune-out wavelengths measured with an atom interferometer are sensitive to laboratory rotation rates because of the Sagnac effect, vector polarizability, and dispersion compensation. We observed shifts in measured tune-out wavelengths as large as 213 pm with a potassium atom beam interferometer, and we explore how these shifts can be used for an atom interferometer gyroscope.

  18. Analyze and experiment on AC magnetic field's effect to fiber optic gyroscopes in compact stabilization control systems

    Science.gov (United States)

    Zhang, Chao; Mao, Yao; Tian, Jing; Li, Zhijun

    2015-10-01

    Fiber optic gyroscopes (FOG) are getting more and more attention in areas such as stabilization control systems as they are all solid state and have a wide bandwidth. In stabilization systems that require wide bandwidth control, motors are usually used as actuating mechanism for active disturbance restrain. Voice coil motors (VCMs) are usually used in compact stabilization systems that require large torque and fast response. However, AC magnetic field, which can affect the output of FOG due to Faraday effect, will be generated during operation of VCMs. The frequency range affected by the AC magnetic field to the FOG's output is the same as VCMs drive signal frequency range, which is also exactly the stabilization system's working range. Therefore the effect of the AC magnetic field to FOGs must be evaluated to verify the feasibility of a stable system design that uses both FOGs and VCMs. In this article, the basic structure and operating principle of stabilization system is introduced. The influence of AC magnetic field to FOG is theoretically analyzed. The magnetic field generated by VCMs is numerically simulated based on the theory deduction of the magnetic field near energized wires. To verify the influence of the VCM generated magnetic field to the FOGs in practical designs, a simplified random fiber coil model is built for it's hard to accurately test the exact polarize axis's twisting rate in a fiber coil. The influence to the FOG's output of different random coil model is simulated and the result shows a same trend that the influence of the VCM's magnetic field to the FOG is reduced as the distance between the VCM and the FOG increasing. The influence of a VCM to a FOG with the same parameters is experimentally tested. In the Fourier transformed FOG data the same frequency point as the VCM drive signal frequency can be read. The result fit simulated result that as the distance increases, the influence decreases. The amplitude of the frequency point is just

  19. Principles of project management

    Science.gov (United States)

    1982-01-01

    The basic principles of project management as practiced by NASA management personnel are presented. These principles are given as ground rules and guidelines to be used in the performance of research, development, construction or operational assignments.

  20. Mach's Holographic Principle

    OpenAIRE

    Khoury, Justin; Parikh, Maulik

    2006-01-01

    Mach's principle is the concept that inertial frames are determined by matter. We propose and implement a precise formulation of Mach's principle in which matter and geometry are in one-to-one correspondence. Einstein's equations are not modified and no selection principle is applied to their solutions; Mach's principle is realized wholly within Einstein's general theory of relativity. The key insight is the observation that, in addition to bulk matter, one can also add boundary matter. Speci...

  1. Investigation of a geodesy coexperiment to the Gravity Probe B relativity gyroscope program

    Science.gov (United States)

    Everitt, C. W. F.; Parkinson, Bradford W.; Tapley, Mark

    1993-01-01

    Geodesy is the science of measuring the gravitational field of and positions on the Earth. Estimation of the gravitational field via gravitation gradiometry, the measurement of variations in the direction and magnitude of gravitation with respect to position, is this dissertation's focus. Gravity Probe B (GP-B) is a Stanford satellite experiment in gravitational physics. GP-B will measure the precession the rotating Earth causes on the space time around it by observing the precessions of four gyroscopes in a circular, polar, drag-free orbit at 650 km altitude. The gyroscopes are nearly perfect niobium-coated spheres of quartz, operating at 1.8 K to permit observations with extremely low thermal noise. The permissible gyroscope drift rate is miniscule, so the torques on the gyros must be tiny. A drag-free control system, by canceling accelerations caused by nongravitational forces, minimizes the support forces and hence torques. The GP-B system offers two main possibilities for geodesy. One is as a drag-free satellite to be used in trajectory-based estimates of the Earth's gravity field. We described calculations involving that approach in our previous reports, including comparison of laser only, GPS only, and combined tracking and a preliminary estimate of the possibility of estimating relativistic effects on the orbit. The second possibility is gradiometry. This technique has received a more cursory examination in previous reports, so we concentrate on it here. We explore the feasibility of using the residual suspension forces centering the GP-B gyros as gradiometer signals for geodesy. The objective of this work is a statistical prediction of the formal uncertainty in an estimate of the Earth's gravitation field using data from GP-B. We perform an instrument analysis and apply two mathematical techniques to predict uncertainty. One is an analytical approach using a flat-Earth approximation to predict geopotential information quality as a function of spatial

  2. Simulation of Malfunctions for the ISS Double-Gimbal Control Moment Gyroscope

    Science.gov (United States)

    Inampudi, Ravi; Gordeuk, John

    2016-01-01

    This paper presents a simplified approach to simulation of malfunctions of the Control Moment Gyroscope (CMG) on board the International Space Station (ISS). These malfunctions will be used as part of flight training of CMG failure scenarios in the guidance navigation control (GNC) subsystem of the Training Systems for 21st Century (TS21) simulator. The CMG malfunctions are grouped under mechanical, thermal and electrical categories. A malfunction can be as simple as one which only affects the telemetry or a complex one that changes the state and behavior of the CMG model. In both cases, the ISS GNC flight software will read the telemetry and respond accordingly. The user executes these malfunctions by supplying conditional data which modify internal model states and then elicit a response as seen on the user displays. Ground operators and crew on board the ISS use CMG malfunction procedures to better understand and respond to anomalies observed within the CMG subsystem.

  3. Study on vacuum packaging reliability of micromachined quartz tuning fork gyroscopes

    Science.gov (United States)

    Fan, Maoyan; Zhang, Lifang

    2017-09-01

    Packaging technology of the micromachined quartz tuning fork gyroscopes by vacuum welding has been experimentally studied. The performance of quartz tuning fork is influenced by the encapsulation shell, encapsulation method and fixation of forks. Alloy solder thick film is widely used in the package to avoid the damage of the chip structure by the heat resistance and hot temperature, and this can improve the device performance and welding reliability. The results show that the bases and the lids plated with gold and nickel can significantly improve the airtightness and reliability of the vacuum package. Vacuum packaging is an effective method to reduce the vibration damping, improve the quality factor and further enhance the performance. The threshold can be improved nearly by 10 times.

  4. Common-mode noise reduction in an atomic spin gyroscope using optical differential detection.

    Science.gov (United States)

    Duan, Lihong; Quan, Wei; Jiang, Liwei; Fan, Wenfeng; Ding, Ming; Hu, Zhaohui; Fang, Jiancheng

    2017-09-20

    Optical rotation of linearly polarized light is used to measure atom spin precession in an atomic spin gyroscope (ASG). However, the common-mode noise in the polarization measurement seriously affects the performance of the sensitive ASG. Here we propose an optical differential detection method based on the photoelastic polarization modulation, which could effectively eliminate the light power fluctuation of the laser source and optical elements, while removing the polarization noise and the residual birefringence. The feasibility and efficiency of this method have been verified experimentally. The rotation sensitivity of the ASG is an order of magnitude better, and the long-time stability is significantly improved. In addition, this method is easier to implement because noise sources do not need to be strictly distinguished.

  5. Temperature Dependence of Faraday Effect-Induced Bias Error in a Fiber Optic Gyroscope.

    Science.gov (United States)

    Li, Xuyou; Liu, Pan; Guang, Xingxing; Xu, Zhenlong; Guan, Lianwu; Li, Guangchun

    2017-09-07

    Improving the performance of interferometric fiber optic gyroscope (IFOG) in harsh environments, such as magnetic field and temperature field variation, is necessary for its practical applications. This paper presents an investigation of Faraday effect-induced bias error of IFOG under varying temperature. Jones matrix method is utilized to formulize the temperature dependence of Faraday effect-induced bias error. Theoretical results show that the Faraday effect-induced bias error changes with the temperature in the non-skeleton polarization maintaining (PM) fiber coil. This phenomenon is caused by the temperature dependence of linear birefringence and Verdet constant of PM fiber. Particularly, Faraday effect-induced bias errors of two polarizations always have opposite signs that can be compensated optically regardless of the changes of the temperature. Two experiments with a 1000 m non-skeleton PM fiber coil are performed, and the experimental results support these theoretical predictions. This study is promising for improving the bias stability of IFOG.

  6. Anisotropic kinetic energy release and gyroscopic behavior of CO2 super rotors from an optical centrifuge

    Science.gov (United States)

    Murray, Matthew J.; Ogden, Hannah M.; Mullin, Amy S.

    2017-10-01

    An optical centrifuge is used to generate an ensemble of CO2 super rotors with oriented angular momentum. The collision dynamics and energy transfer behavior of the super rotor molecules are investigated using high-resolution transient IR absorption spectroscopy. New multipass IR detection provides improved sensitivity to perform polarization-dependent transient studies for rotational states with 76 ≤ J ≤ 100. Polarization-dependent measurements show that the collision-induced kinetic energy release is spatially anisotropic and results from both near-resonant energy transfer between super rotor molecules and non-resonant energy transfer between super rotors and thermal molecules. J-dependent studies show that the extent and duration of the orientational anisotropy increase with rotational angular momentum. The super rotors exhibit behavior akin to molecular gyroscopes, wherein molecules with larger amounts of angular momentum are less likely to change their angular momentum orientation through collisions.

  7. Under-Coupling Whispering Gallery Mode Resonator Applied to Resonant Micro-Optic Gyroscope

    Directory of Open Access Journals (Sweden)

    Kun Qian

    2017-01-01

    Full Text Available As an important sensing element, the whispering gallery mode resonator (WGMR parameters seriously affect the resonant micro-optic gyroscope (RMOG performance. This work proposes an under-coupling resonator to improve the resonator’s Q value and to optimize the coupling coefficient to maximize the RMOG’s sensitivity. GeO2-doped silica waveguide-type resonators with different coupling coefficients were simulated, designed, fabricated and tested. An under-coupling ring resonator with a quality factor of 10 million is reported. The RMOG system was built based on this resonator and the scale factor was tested on a uniaxial high-precision rotating platform. Experimental results show that this resonator could improve the RMOG sensitivity by five times.

  8. Effects of gain medium parameters on the sensitivity of semiconductor ring laser gyroscope

    Science.gov (United States)

    Khandelwal, Arpit; Hossein, Y. S.; Syed, Azeemuddin; Sayeh, M. R.; Nayak, Jagannath

    2017-09-01

    The semiconductor gain medium has rich non-linear dynamics and several internal parameters influence the generation and propagation of light through it. With the gain medium being an integral part of semiconductor ring laser gyroscope (SRLG) cavity, its parameters affect the overall performance of the gyro. The effect is further elevated in integrated SRLG due to stronger confinement of charge carriers and photons leading to a more intense interaction between them. In this paper, we evaluate the influence of semiconductor gain medium parameters such as gain saturation coefficient, linewidth, internal quantum efficiency etc. on the sensitivity of bulk fiber-optic SRLG. Ways of controlling these parameters and optimizing their values to enhance the performance of SRLG are also discussed.

  9. Study of double-ring slow-light gyroscope with two input-output waveguides

    Science.gov (United States)

    Gu, Hong; Liu, Xiao-qing

    2017-10-01

    A novel structure of double-ring slow-light gyroscope with two input-output waveguides is studied. We utilize interferometric detection method, and sufficiently combine the advantages of Interferometric Fiber Optic Gyro (I-FOG) and Resonator Optic Gyro (ROG). The responses of the structure are derived and simulated. Here two experimental schemes are also proposed. By applying a square wave to the integrated phase modulator, we can make the structure work at the highest sensitivity. After applied the square wave, the system runs at linear zone, thus the angular velocity can be obtained according to the linear relationship between the phase difference and the angular velocity. The optimal parameters for the largest phase difference of light signal monitored at different output ports are investigated. Some comparisons are done in the condition of various values of transmission loss coefficients.

  10. Compensation method for temperature error of fiber optical gyroscope based on relevance vector machine.

    Science.gov (United States)

    Wang, Guochen; Wang, Qiuying; Zhao, Bo; Wang, Zhenpeng

    2016-02-10

    Aiming to improve the bias stability of the fiber optical gyroscope (FOG) in an ambient temperature-change environment, a temperature-compensation method based on the relevance vector machine (RVM) under Bayesian framework is proposed and applied. Compared with other temperature models such as quadratic polynomial regression, neural network, and the support vector machine, the proposed RVM method possesses higher accuracy to explain the temperature dependence of the FOG gyro bias. Experimental results indicate that, with the proposed RVM method, the bias stability of an FOG can be apparently reduced in the whole temperature ranging from -40°C to 60°C. Therefore, the proposed method can effectively improve the adaptability of the FOG in a changing temperature environment.

  11. Under-Coupling Whispering Gallery Mode Resonator Applied to Resonant Micro-Optic Gyroscope.

    Science.gov (United States)

    Qian, Kun; Tang, Jun; Guo, Hao; Liu, Wenyao; Liu, Jun; Xue, Chenyang; Zheng, Yongqiu; Zhang, Chengfei

    2017-01-06

    As an important sensing element, the whispering gallery mode resonator (WGMR) parameters seriously affect the resonant micro-optic gyroscope (RMOG) performance. This work proposes an under-coupling resonator to improve the resonator's Q value and to optimize the coupling coefficient to maximize the RMOG's sensitivity. GeO₂-doped silica waveguide-type resonators with different coupling coefficients were simulated, designed, fabricated and tested. An under-coupling ring resonator with a quality factor of 10 million is reported. The RMOG system was built based on this resonator and the scale factor was tested on a uniaxial high-precision rotating platform. Experimental results show that this resonator could improve the RMOG sensitivity by five times.

  12. A New Optical Method for Suppressing Radial Magnetic Error in a Depolarized Interference Fiber Optic Gyroscope.

    Science.gov (United States)

    Zhou, Yanru; Zhao, Yuxiang; Zhang, Dengwei; Shu, Xiaowu; Che, Shuangliang

    2018-01-31

    Based on the theory of the radial magnetic error (RME) in depolarized interference fiber optic gyroscopes (D-IFOGs) under magnetic field, a new optical method is proposed to decrease the RME by adding a suppressing section fiber (SSF) in D-IFOGs. A related theoretical model is established, and the solutions of the parameters of the SSF are obtained with numerical calculations. Then the results of the suppressed RME are simulated. An experimental system is set up to verify the theory and simulation, and the experimental results prove that the RME can be suppressed effectively with a SSF added in the D-IFOG. The magnitude of the RME can be reduced to one-tenth of the original.

  13. Pseudo-random-bit-sequence phase modulation for reduced errors in a fiber optic gyroscope.

    Science.gov (United States)

    Chamoun, Jacob; Digonnet, Michel J F

    2016-12-15

    Low noise and drift in a laser-driven fiber optic gyroscope (FOG) are demonstrated by interrogating the sensor with a low-coherence laser. The laser coherence was reduced by broadening its optical spectrum using an external electro-optic phase modulator driven by either a sinusoidal or a pseudo-random bit sequence (PRBS) waveform. The noise reduction measured in a FOG driven by a modulated laser agrees with the calculations based on the broadened laser spectrum. Using PRBS modulation, the linewidth of a laser was broadened from 10 MHz to more than 10 GHz, leading to a measured FOG noise of only 0.00073  deg/√h and a drift of 0.023  deg/h. To the best of our knowledge, these are the lowest noise and drift reported in a laser-driven FOG, and this noise is below the requirement for the inertial navigation of aircraft.

  14. Measurements of complex coupling coefficients in a ring resonator of a laser gyroscope

    Science.gov (United States)

    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.

  15. Compensation of thermal strain induced polarization nonreciprocity in dual-polarization fiber optic gyroscope.

    Science.gov (United States)

    Luo, Rongya; Li, Yulin; Deng, Sheng; He, Dong; Peng, Chao; Li, Zhengbin

    2017-10-30

    Dual-polarization interferometric fiber optic gyroscope (IFOG) is a novel scheme in which the polarization nonreciprocal (PN) phase error of the two orthogonal polarizations can be optically compensated. In this work, we investigate the effective of PN phase error compensation under varying temperature. It is proved that, the thermally induced strain deforms the fiber, and results in perturbations on the birefringence and polarization cross coupling which degrades the IFOG's stability. A wave propagation model and analytical expressions of PN phase error are derived by using coupled-wave equation and Jones matrix. We theoretically and experimentally verify that, although the single-mode (SM) and polarization-maintaining (PM) fiber coils behave different owing to their intrinsic properties of wave propagation, the thermal strain induced PN phase error can still be compensated under slow and adiabatic temperature variations. This could be a promising feature to overcome the temperature fragility of IFOG.

  16. High finesse silica waveguide ring resonators for resonant micro-optic gyroscopes

    Science.gov (United States)

    Zhang, Jianjie; Li, Hanzhao; Ma, Huilian; Jin, Zhonghe

    2017-04-01

    A high-finesse silica waveguide ring resonator (WRR) is designed and a new record is demonstrated experimentally. The finesse and the resonant depth of the silica WRR with a length of 7.9 cm and a diameter of 2.5 cm are 196.7 and 98%, respectively. In addition, the silica WRR is pigtailed with single-polarization fiber to improve the polarization extinction ratio thus to reduce the polarization error. With the application of this high-finesse and high polarization extinction ratio WRR to the resonant micro-optic gyroscope (RMOG), a bias stability of 0.004°/s was observed over a one-hour timeframe.

  17. Stabilizing Gyroscopic Modes in Magnetic-Bearing-Supported Flywheels by Using Cross-Axis Proportional Gains

    Science.gov (United States)

    Brown, Gerald V.; Kascak, Albert F.; Jansen, Ralph H.; Dever, Timothy P.; Duffy, Kirsten P.

    2006-01-01

    For magnetic-bearing-supported high-speed rotating machines with significant gyroscopic effects, it is necessary to stabilize forward and backward tilt whirling modes. Instability or low damping of these modes can prevent the attainment of desired shaft speed. We show analytically that both modes can be stabilized by using cross-axis proportional gains and high- and low-pass filters in the magnetic bearing controller. Furthermore, at high shaft speeds, where system phase lags degrade the stability of the forward-whirl mode, a phasor advance of the control signal can partially counteract the phase lag. In some range of high shaft speed, the derivative gain for the tilt modes (essential for stability for slowly rotating shafts) can be removed entirely. We show analytically how the tilt eigenvalues depend on shaft speed and on various controller feedback parameters.

  18. Integrated Power and Attitude Control for a Spacecraft with Flywheels and Control Moment Gyroscopes

    Science.gov (United States)

    Roithmayr, Carlos M.; Karlgaard, Christopher D.; Kumar, Renjith R.; Bose, David M.

    2003-01-01

    A law is designed for simultaneous control of the orientation of an Earth-pointing spacecraft, the energy stored by counter-rotating flywheels, and the angular momentum of the flywheels and control moment gyroscopes used together as all integrated set of actuators for attitude control. General. nonlinear equations of motion are presented in vector-dyadic form, and used to obtain approximate expressions which are then linearized in preparation for design of control laws that include feedback of flywheel kinetic energy error as it means of compensating for damping exerted by rotor bearings. Two flywheel 'steering laws' are developed such that torque commanded by all attitude control law is achieved while energy is stored or discharged at the required rate. Using the International Space Station as an example, numerical simulations are performed to demonstrate control about a torque equilibrium attitude and illustrate the benefits of kinetic energy error feedback.

  19. A bicycle can be self-stable without gyroscopic or caster effects.

    Science.gov (United States)

    Kooijman, J D G; Meijaard, J P; Papadopoulos, Jim M; Ruina, Andy; Schwab, A L

    2011-04-15

    A riderless bicycle can automatically steer itself so as to recover from falls. The common view is that this self-steering is caused by gyroscopic precession of the front wheel, or by the wheel contact trailing like a caster behind the steer axis. We show that neither effect is necessary for self-stability. Using linearized stability calculations as a guide, we built a bicycle with extra counter-rotating wheels (canceling the wheel spin angular momentum) and with its front-wheel ground-contact forward of the steer axis (making the trailing distance negative). When laterally disturbed from rolling straight, this bicycle automatically recovers to upright travel. Our results show that various design variables, like the front mass location and the steer axis tilt, contribute to stability in complex interacting ways.

  20. Modified Cross Feedback Control for a Magnetically Suspended Flywheel Rotor with Significant Gyroscopic Effects

    Directory of Open Access Journals (Sweden)

    Yuan Ren

    2014-01-01

    Full Text Available For magnetically suspended rigid rotors (MSRs with significant gyroscopic effects, phase lag of the control channel is the main factor influencing the system nutation stability and decoupling performance. At first, this paper proves that the phase lag of the cross channel instead of the decentralized channel is often the main factor influencing the system nutation stability at high speeds. Then a modified cross feedback control strategy based on the phase compensation of cross channel is proposed to improve the stability and decoupling performances. The common issues associated with the traditional control methods have been successfully resolved by this method. Analysis, simulation, and experimental results are presented to demonstrate the feasibility and superiority of the proposed control method.

  1. From gyroscopic to thermal motion: a crossover in the dynamics of molecular superrotors

    CERN Document Server

    Milner, A A; Rezaiezadeh, K; Milner, V

    2015-01-01

    Localized heating of a gas by intense laser pulses leads to interesting acoustic, hydrodynamic and optical effects with numerous applications in science and technology, including controlled wave guiding and remote atmosphere sensing. Rotational excitation of molecules can serve as the energy source for raising the gas temperature. Here, we study the dynamics of energy transfer from the molecular rotation to heat. By optically imaging a cloud of molecular superrotors, created with an optical centrifuge, we experimentally identify two separate and qualitatively different stages of its evolution. The first non-equilibrium "gyroscopic" stage is characterized by the modified optical properties of the centrifuged gas - its refractive index and optical birefringence, owing to the ultrafast directional molecular rotation, which survives tens of collisions. The loss of rotational directionality is found to overlap with the release of rotational energy to heat, which triggers the second stage of thermal expansion. The ...

  2. Method for suppressing the bias drift of interferometric all-fiber optic gyroscopes.

    Science.gov (United States)

    Wang, Xinyue; He, Changhong; Wang, Ziyu

    2011-04-01

    We propose a simple and, to our knowledge, novel method for suppressing the bias drift of interferometric all-fiber optic gyroscopes (I-FOGs) and for self-calibrating the bias of I-FOGs to zero. Using a square wave to reverse the polarity of the sinusoidal voltage on a piezoelectric (PZT) modulator periodically, and calculating the output signal of a demodulator circuit in-phase with the square wave by a digital signal processor (DSP), we successfully reduce the bias drift of I-FOGs. Experimental results show that, at room temperature, the proposed method dramatically reduces the bias instability of an I-FOG from 0.201 deg/h to 0.102 deg/h. With this method, the I-FOGs no longer need zero calibration.

  3. Adaptive Sliding Mode Control of MEMS Gyroscope Based on Neural Network Approximation

    Directory of Open Access Journals (Sweden)

    Yuzheng Yang

    2014-01-01

    Full Text Available An adaptive sliding controller using radial basis function (RBF network to approximate the unknown system dynamics microelectromechanical systems (MEMS gyroscope sensor is proposed. Neural controller is proposed to approximate the unknown system model and sliding controller is employed to eliminate the approximation error and attenuate the model uncertainties and external disturbances. Online neural network (NN weight tuning algorithms, including correction terms, are designed based on Lyapunov stability theory, which can guarantee bounded tracking errors as well as bounded NN weights. The tracking error bound can be made arbitrarily small by increasing a certain feedback gain. Numerical simulation for a MEMS angular velocity sensor is investigated to verify the effectiveness of the proposed adaptive neural control scheme and demonstrate the satisfactory tracking performance and robustness.

  4. Two self-test methods applied to an inertial system problem. [estimating gyroscope and accelerometer bias

    Science.gov (United States)

    Willsky, A. S.; Deyst, J. J.; Crawford, B. S.

    1975-01-01

    The paper describes two self-test procedures applied to the problem of estimating the biases in accelerometers and gyroscopes on an inertial platform. The first technique is the weighted sum-squared residual (WSSR) test, with which accelerator bias jumps are easily isolated, but gyro bias jumps are difficult to isolate. The WSSR method does not take full advantage of the knowledge of system dynamics. The other technique is a multiple hypothesis method developed by Buxbaum and Haddad (1969). It has the advantage of directly providing jump isolation information, but suffers from computational problems. It might be possible to use the WSSR to detect state jumps and then switch to the BH system for jump isolation and estimate compensation.

  5. A Novel Temperature Compensation Method for a MEMS Gyroscope Oriented on a Periphery Circuit

    Directory of Open Access Journals (Sweden)

    Huiliang Cao

    2013-09-01

    Full Text Available This paper investigates temperature compensation methods used for the scale factor and bias of the MEMS gyroscope within the temperature range from − 40°C to 60°C. The structure and periphery monitor circuit are introduced. Then the determinant elements of the MEMS gyroscope's scale factor are analysed and the results indicate that scale factor is directly proportional to drive amplitude and sense loop gain and is inversely proportional to the frequency gap between two modes. After that, the compensation methods are proposed, the thermal resistor's positive temperature coefficient (tempco is utilized to calibrate the scale factor's tempco through regulating the drive mode amplitude and the sense loop gain, and each method is applied respectively and the results are contrasted. The test results of the two specimens express that the most effective compensation method could decrease the scale factor's tempco from 693ppm/°C (640ppm/°C to 250ppm/°C (257ppm/°C, improving it by 63.9% (59.8%. Finally, a method of declining bias's tempco is investigated and implemented after scale factor compensation. A summator with a thermal resistor is utilized at the output level and decreases the bias's tempco from 103.89°/h/°C (100.78°/h/°C to 9.70°/h/°C (12°/h/°C improving it by 90.7% (88%. Repeat tests are performed based on two specimens to prove the repeatability and reproducibility of the methods.

  6. An MR-compatible gyroscope-based arm movement tracking system.

    Science.gov (United States)

    Shirinbayan, S Iman; Rieger, Jochem W

    2017-03-15

    Functional magnetic resonance imaging is well suited to link neural population activation with movement parameters of complex natural arm movements. However, currently existing MR-compatible arm tracking devices are not constructed to measure arm joint movement parameters of unrestricted movements. Therefore, to date most research focuses on simple arm movements or includes very little knowledge about the actual movement kinematics. We developed a low cost gyroscope-based arm movement tracking system (GAMTS) that features MR-compatibility. The system consists of dual-axis analogue gyroscopes that measure rotations of upper and lower arm joints. After MR artifact reduction, the rotation angles of the individual arm joints are calculated and used to animate a realistic arm model that is implemented in the OpenSim platform. The OpenSim platform can then provide the kinematics of any point on the arm model. In order to demonstrate the capabilities of the system, we first assessed the quality of reconstructed wrist movements in a low-noise environment where typical MR-related problems are absent and finally, we validated the reconstruction in the MR environment. The system provides the kinematics of the whole arm when natural unrestricted arm movements are performed inside the MR-scanner. The GAMTS is reliably capable of reconstructing the kinematics of trajectories and the reconstruction error is small in comparison with the movement induced variation of speed, displacement, and rotation. Moreover, the system can be used to probe brain areas for their correlation with movement kinematics. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Behavior of a test gyroscope moving towards a rotating traversable wormhole

    Science.gov (United States)

    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.

  8. Design and Verification of a Digital Controller for a 2-Piece Hemispherical Resonator Gyroscope.

    Science.gov (United States)

    Lee, Jungshin; Yun, Sung Wook; Rhim, Jaewook

    2016-04-20

    A Hemispherical Resonator Gyro (HRG) is the Coriolis Vibratory Gyro (CVG) that measures rotation angle or angular velocity using Coriolis force acting the vibrating mass. A HRG can be used as a rate gyro or integrating gyro without structural modification by simply changing the control scheme. In this paper, differential control algorithms are designed for a 2-piece HRG. To design a precision controller, the electromechanical modelling and signal processing must be pre-performed accurately. Therefore, the equations of motion for the HRG resonator with switched harmonic excitations are derived with the Duhamel Integral method. Electromechanical modeling of the resonator, electric module and charge amplifier is performed by considering the mode shape of a thin hemispherical shell. Further, signal processing and control algorithms are designed. The multi-flexing scheme of sensing, driving cycles and x, y-axis switching cycles is appropriate for high precision and low maneuverability systems. The differential control scheme is easily capable of rejecting the common mode errors of x, y-axis signals and changing the rate integrating mode on basis of these studies. In the rate gyro mode the controller is composed of Phase-Locked Loop (PLL), amplitude, quadrature and rate control loop. All controllers are designed on basis of a digital PI controller. The signal processing and control algorithms are verified through Matlab/Simulink simulations. Finally, a FPGA and DSP board with these algorithms is verified through experiments.

  9. Design and Verification of a Digital Controller for a 2-Piece Hemispherical Resonator Gyroscope

    Directory of Open Access Journals (Sweden)

    Jungshin Lee

    2016-04-01

    Full Text Available A Hemispherical Resonator Gyro (HRG is the Coriolis Vibratory Gyro (CVG that measures rotation angle or angular velocity using Coriolis force acting the vibrating mass. A HRG can be used as a rate gyro or integrating gyro without structural modification by simply changing the control scheme. In this paper, differential control algorithms are designed for a 2-piece HRG. To design a precision controller, the electromechanical modelling and signal processing must be pre-performed accurately. Therefore, the equations of motion for the HRG resonator with switched harmonic excitations are derived with the Duhamel Integral method. Electromechanical modeling of the resonator, electric module and charge amplifier is performed by considering the mode shape of a thin hemispherical shell. Further, signal processing and control algorithms are designed. The multi-flexing scheme of sensing, driving cycles and x, y-axis switching cycles is appropriate for high precision and low maneuverability systems. The differential control scheme is easily capable of rejecting the common mode errors of x, y-axis signals and changing the rate integrating mode on basis of these studies. In the rate gyro mode the controller is composed of Phase-Locked Loop (PLL, amplitude, quadrature and rate control loop. All controllers are designed on basis of a digital PI controller. The signal processing and control algorithms are verified through Matlab/Simulink simulations. Finally, a FPGA and DSP board with these algorithms is verified through experiments.

  10. Minimum magnetizability principle

    Science.gov (United States)

    Tanwar, Akhilesh; Pal, Sourav; Ranjan Roy, Debesh; Kumar Chattaraj, Pratim

    2006-08-01

    A new electronic structure principle, viz., the minimum magnetizability principle, has been proposed and also has been verified through ab initio calculations, to extend the domain of applicability of the conceptual density functional theory in explaining the magnetic interactions and magnetochemistry. This principle may be stated as "a stable configuration/conformation of a molecule or a favorable chemical process is associated with a minimum value of the magnetizability." The behavior of paramagnetic and diamagnetic components has been separately studied.

  11. Minimum Magnetizability Principle

    OpenAIRE

    Tanwar, Akhilesh; Roy, Debesh Ranjan; Pal, Sourav; Chattaraj, Pratim Kumar

    2006-01-01

    A new electronic structure principle, viz. the minimum magnetizability principle (MMP) has been proposed and also has been verified through ab initio calculations, to extend the domain of applicability of the conceptual density functional theory (DFT) in explaining the magnetic interactions and magnetochemistry. This principle may be stated as, "A stable configuration/conformation of a molecule or a favorable chemical process is associated with a minimum value of the magnetizability". It has ...

  12. Fusion research principles

    CERN Document Server

    Dolan, Thomas James

    2013-01-01

    Fusion Research, Volume I: Principles provides a general description of the methods and problems of fusion research. The book contains three main parts: Principles, Experiments, and Technology. The Principles part describes the conditions necessary for a fusion reaction, as well as the fundamentals of plasma confinement, heating, and diagnostics. The Experiments part details about forty plasma confinement schemes and experiments. The last part explores various engineering problems associated with reactor design, vacuum and magnet systems, materials, plasma purity, fueling, blankets, neutronics

  13. Biomechanics principles and practices

    CERN Document Server

    Peterson, Donald R

    2014-01-01

    Presents Current Principles and ApplicationsBiomedical engineering is considered to be the most expansive of all the engineering sciences. Its function involves the direct combination of core engineering sciences as well as knowledge of nonengineering disciplines such as biology and medicine. Drawing on material from the biomechanics section of The Biomedical Engineering Handbook, Fourth Edition and utilizing the expert knowledge of respected published scientists in the application and research of biomechanics, Biomechanics: Principles and Practices discusses the latest principles and applicat

  14. Database principles programming performance

    CERN Document Server

    O'Neil, Patrick

    2014-01-01

    Database: Principles Programming Performance provides an introduction to the fundamental principles of database systems. This book focuses on database programming and the relationships between principles, programming, and performance.Organized into 10 chapters, this book begins with an overview of database design principles and presents a comprehensive introduction to the concepts used by a DBA. This text then provides grounding in many abstract concepts of the relational model. Other chapters introduce SQL, describing its capabilities and covering the statements and functions of the programmi

  15. APPLYING THE PRINCIPLES OF ACCOUNTING IN

    OpenAIRE

    NAGY CRISTINA MIHAELA; SABĂU CRĂCIUN; ”Tibiscus” University of Timişoara, Faculty of Economic Science

    2015-01-01

    The application of accounting principles (accounting principle on accrual basis; principle of business continuity; method consistency principle; prudence principle; independence principle; the principle of separate valuation of assets and liabilities; intangibility principle; non-compensation principle; the principle of substance over form; the principle of threshold significance) to companies that are in bankruptcy procedure has a number of particularities. Thus, some principl...

  16. Novel Compensation Scheme for the Modulation Gain to Suppress the Quantization-Induced Bias in a Fiber Optic Gyroscope.

    Science.gov (United States)

    Pan, Xiong; Liu, Pengcheng; Zhang, Shaobo; Jin, Jing; Song, Ningfang

    2017-04-10

    A novel digital compensation scheme is demonstrated to control the gain of the modulation chain and suppress the influence of quantization error on bias. The error produced by the quantization multiplied by the scaling factor is theoretically analyzed. Simulations indicate that the quantization error varies with the input angular velocity and temperature, which is verified by experiments. By switching the integration and compression operations in the modulation chain, this quantization error is reduced, while automatic reset of the digital phase ramp register is achieved. We test the scheme in a fiber optic gyroscope. The test results reveal that the quantization-induced bias is suppressed and the residual bias is two times less than the desired accuracy with data accumulated over one-second sample interval. The scheme is a feasible method to miniaturize fiber optic gyroscope using a totally digital circuit for compensation of the modulation gain.

  17. Predicting the random drift of MEMS gyroscope based on K-means clustering and OLS RBF Neural Network

    Science.gov (United States)

    Wang, Zhen-yu; Zhang, Li-jie

    2017-10-01

    Measure error of the sensor can be effectively compensated with prediction. Aiming at large random drift error of MEMS(Micro Electro Mechanical System))gyroscope, an improved learning algorithm of Radial Basis Function(RBF) Neural Network(NN) based on K-means clustering and Orthogonal Least-Squares (OLS) is proposed in this paper. The algorithm selects the typical samples as the initial cluster centers of RBF NN firstly, candidates centers with K-means algorithm secondly, and optimizes the candidate centers with OLS algorithm thirdly, which makes the network structure simpler and makes the prediction performance better. Experimental results show that the proposed K-means clustering OLS learning algorithm can predict the random drift of MEMS gyroscope effectively, the prediction error of which is 9.8019e-007°/s and the prediction time of which is 2.4169e-006s

  18. Static deflection and pull-in instability analysis of an electrostatically actuated mirocantilever gyroscope considering geometric nonlinearities

    Energy Technology Data Exchange (ETDEWEB)

    Mojahedi, Mahdi [Sharif University of Technology, Tehran (Iran, Islamic Republic of); Ahmadian, Mohammad Taghi; Firoozabakhsh, Keikhosrow [Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2013-08-15

    In this paper, a mathematical modeling of a microcantilever gyroscope is presented considering the nonlinearities of the system due to electrostatic forces, fringing field, geometry and the inertial terms. The microgyroscope is actuated and detected by electrostatic methods and subjected to coupled bending oscillations. First a system of two nonlinear integro-differential equations is derived which describes flexural-flexural motion of electrostatically actuated and detected microbeam gyroscopes. Afterward, static deflection and pull-in instability of the microgyroscopes acted upon by DC voltages in both (driving and sensing) directions are studied for different parameters. The model's predictions are in good agreement with the experimental data found in the literature and finite element simulation. Results show that the nonlinearities become important when pull-in happens.

  19. Gyroscope-driven mouse pointer with an EMOTIV® EEG headset and data analysis based on Empirical Mode Decomposition.

    Science.gov (United States)

    Rosas-Cholula, Gerardo; Ramirez-Cortes, Juan Manuel; Alarcon-Aquino, Vicente; Gomez-Gil, Pilar; Rangel-Magdaleno, Jose de Jesus; Reyes-Garcia, Carlos

    2013-08-14

    This paper presents a project on the development of a cursor control emulating the typical operations of a computer-mouse, using gyroscope and eye-blinking electromyographic signals which are obtained through a commercial 16-electrode wireless headset, recently released by Emotiv. The cursor position is controlled using information from a gyroscope included in the headset. The clicks are generated through the user's blinking with an adequate detection procedure based on the spectral-like technique called Empirical Mode Decomposition (EMD). EMD is proposed as a simple and quick computational tool, yet effective, aimed to artifact reduction from head movements as well as a method to detect blinking signals for mouse control. Kalman filter is used as state estimator for mouse position control and jitter removal. The detection rate obtained in average was 94.9%. Experimental setup and some obtained results are presented.

  20. Gyroscope-Driven Mouse Pointer with an EMOTIV® EEG Headset and Data Analysis Based on Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Carlos Reyes-Garcia

    2013-08-01

    Full Text Available This paper presents a project on the development of a cursor control emulating the typical operations of a computer-mouse, using gyroscope and eye-blinking electromyographic signals which are obtained through a commercial 16-electrode wireless headset, recently released by Emotiv. The cursor position is controlled using information from a gyroscope included in the headset. The clicks are generated through the user’s blinking with an adequate detection procedure based on the spectral-like technique called Empirical Mode Decomposition (EMD. EMD is proposed as a simple and quick computational tool, yet effective, aimed to artifact reduction from head movements as well as a method to detect blinking signals for mouse control. Kalman filter is used as state estimator for mouse position control and jitter removal. The detection rate obtained in average was 94.9%. Experimental setup and some obtained results are presented.

  1. Gyroscope-Driven Mouse Pointer with an EMOTIV® EEG Headset and Data Analysis Based on Empirical Mode Decomposition

    Science.gov (United States)

    Rosas-Cholula, Gerardo; Ramirez-Cortes, Juan Manuel; Alarcon-Aquino, Vicente; Gomez-Gil, Pilar; Rangel-Magdaleno, Jose de Jesus; Reyes-Garcia, Carlos

    2013-01-01

    This paper presents a project on the development of a cursor control emulating the typical operations of a computer-mouse, using gyroscope and eye-blinking electromyographic signals which are obtained through a commercial 16-electrode wireless headset, recently released by Emotiv. The cursor position is controlled using information from a gyroscope included in the headset. The clicks are generated through the user's blinking with an adequate detection procedure based on the spectral-like technique called Empirical Mode Decomposition (EMD). EMD is proposed as a simple and quick computational tool, yet effective, aimed to artifact reduction from head movements as well as a method to detect blinking signals for mouse control. Kalman filter is used as state estimator for mouse position control and jitter removal. The detection rate obtained in average was 94.9%. Experimental setup and some obtained results are presented. PMID:23948873

  2. Principles of environmental sciences

    NARCIS (Netherlands)

    Boersema, J.J.; Reijnders, L.

    2009-01-01

    Principles of Environmental Sciences provides a comprehensive picture of the principles, concepts and methods that are applicable to problems originating from the interaction between the living and non-living environment and mankind. Both the analysis of such problems and the way solutions to

  3. The Principles of Leadership.

    Science.gov (United States)

    Burns, Gerald P.

    The primary but not exclusive concern in this monograph is the principles and qualities of dynamic leaders of people rather than of ideas or cultural and artistic pursuits. Theories of leadership in the past, present, and future are discussed, as are the principles, rewards, exercise, and philosophy of leadership. A bibliography is included. (MSE)

  4. Enhancing the sensitivity of three-axis detectable surface acoustic wave gyroscope by using a floating thin piezoelectric membrane

    Science.gov (United States)

    Lee, Munhwan; Lee, Keekeun

    2017-06-01

    A new type of surface acoustic wave (SAW) gyroscope was developed on a floating thin piezoelectric membrane to enhance sensitivity and reliability by removing a bulk noise effect and by importing a higher amplitude of SAW. The developed device constitutes a two-port SAW resonator with a metallic dot array between two interdigital transducers (IDTs), and a one-port SAW delay line. The bulk silicon was completely etched away, leaving only a thin piezoelectric membrane with a thickness of one wavelength. A voltage controlled oscillator (VCO) was connected to a SAW resonator to activate the SAW resonator, while the SAW delay line was connected to the oscilloscope to monitor any variations caused by the Coriolis force. When the device was rotated, a secondary wave was generated, changing the amplitude of the SAW delay line. The highest sensitivity was observed in a device with a full acoustic wavelength thickness of the membrane because most of the acoustic field is confined within an acoustic wavelength thickness from the top surface; moreover, the thin-membrane-based gyroscope eliminates the bulk noise effect flowing along the bulk substrate. The obtained sensitivity and linearity of the SAW gyroscope were ˜27.5 µV deg-1 s-1 and ˜4.3%, respectively. Superior directivity was observed. The device surface was vacuum-sealed using poly(dimethylsiloxane) (PDMS) bonding to eliminate environmental interference. A three-axis detectable gyroscope was also implemented by placing three gyrosensors with the same configuration at right angles to each other on a printed circuit board.

  5. On-chip modulation for rotating sensing of gyroscope based on ring resonator coupled with Mach-Zehnder interferometer.

    Science.gov (United States)

    Zhang, Hao; Chen, Jiayang; Jin, Junjie; Lin, Jian; Zhao, Long; Bi, Zhuanfang; Huang, Anping; Xiao, Zhisong

    2016-01-22

    An improving structure for resonance optical gyro inserting a Mach-Zehnder Interferomete (MZI) into coupler region between ring resonator and straight waveguide was proposed. The different reference phase shift parameters in the MZI arms are tunable by thermo-optic effect and can be optimized at every rotation angular rate point without additional phase bias. Four optimum paths are formed to make the gyroscope to work always at the highest sensitivity.

  6. Experimental study on gyroscopic effect of rotating rotor and wind heading angle on floating wind turbine responses

    OpenAIRE

    Bahramiasl, Shabnam; Abbaspour, Madjid; Karimirad, Madjid

    2017-01-01

    Limited fossil resources, daily increasing rate of demand for energy and the environmental pollution fact, have made people revert to renewable sources of energy as a solution. One type of renewable energy is offshore wind energy which has high potential without any sound and visual noises. Recently a lot of researchers have carried out on the issue of offshore wind turbine. Because of incapability of most of software programs to simulate gyroscopic effect of rotating rotors, in this articles...

  7. Variational principles in physics

    CERN Document Server

    Basdevant, Jean-Louis

    2007-01-01

    Optimization under constraints is an essential part of everyday life. Indeed, we routinely solve problems by striking a balance between contradictory interests, individual desires and material contingencies. This notion of equilibrium was dear to thinkers of the enlightenment, as illustrated by Montesquieu’s famous formulation: "In all magistracies, the greatness of the power must be compensated by the brevity of the duration." Astonishingly, natural laws are guided by a similar principle. Variational principles have proven to be surprisingly fertile. For example, Fermat used variational methods to demonstrate that light follows the fastest route from one point to another, an idea which came to be known as Fermat’s principle, a cornerstone of geometrical optics. Variational Principles in Physics explains variational principles and charts their use throughout modern physics. The heart of the book is devoted to the analytical mechanics of Lagrange and Hamilton, the basic tools of any physicist. Prof. Basdev...

  8. Novel Gyroscopic Mounting for Crystal Oscillators to Increase Short and Medium Term Stability under Highly Dynamic Conditions

    Directory of Open Access Journals (Sweden)

    Maryam Abedi

    2015-06-01

    Full Text Available 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 performance for host vehicle attitude changes. A phase noise improvement of 27 dB maximum and 5.7 dB on average can be achieved in the case of steady state loads, while under sinusoidal vibration conditions, the maximum and average phase noise improvement are as high as 24 dB and 7.5 dB respectively. With this gyroscopic mounting method, random vibration-induced phase noise instability is reduced 30 dB maximum and 8.7 dB on average. Good effects are apparent for crystal g-sensitivity vectors with low elevation angle φ and azimuthal angle β. under highly dynamic conditions, indicating the probability that crystal oscillator instability will be significantly reduced by using the proposed mounting approach.

  9. Modal Tilt/Translate Control and Stability of a Rigid Rotor with Gyroscopics on Active Magnetic Bearings

    Directory of Open Access Journals (Sweden)

    Timothy Dimond

    2012-01-01

    Full Text Available Most industrial rotors supported in active magnetic bearings (AMBs are operated well below the first bending critical speed. Also, they are usually controlled using proportional, integral and derivative controllers, which are set up as modally uncoupled parallel and tilt rotor axes. Gyroscopic effects create mode splitting and a speed-dependent plant. Two AMBs with four axes of control must simultaneously control and stabilize the rotor/AMB system. Various analyses have been published considering this problem for different rotor/AMB configurations. There has not been a fully dimensionless analysis of these rigid rotor AMB systems. This paper will perform this analysis with a modal PD controller in terms of translation mode and tilt mode dimensionless eigenvalues and eigenvectors. The number of independent system parameters is significantly reduced. Dimensionless PD controller gains, the ratio of rotor polar to transverse moments of inertia and a dimensionless speed ratio are used to evaluate a fully general system stability rigid rotor analysis. An objective of this work is to quantify the effects of gyroscopics on rigid rotor AMB systems. These gyroscopic forces reduce the system stability margin. The paper is also intended to help provide a common framework for communication between rotating machinery designers and controls engineers

  10. Design, dynamics and control of an Adaptive Singularity-Free Control Moment Gyroscope actuator for microspacecraft Attitude Determination and Control System

    Science.gov (United States)

    Viswanathan, Sasi Prabhakaran

    Design, dynamics, control and implementation of a novel spacecraft attitude control actuator called the "Adaptive Singularity-free Control Moment Gyroscope" (ASCMG) is presented in this dissertation. In order to construct a comprehensive attitude dynamics model of a spacecraft with internal actuators, the dynamics of a spacecraft with an ASCMG, is obtained in the framework of geometric mechanics using the principles of variational mechanics. The resulting dynamics is general and complete model, as it relaxes the simplifying assumptions made in prior literature on Control Moment Gyroscopes (CMGs) and it also addresses the adaptive parameters in the dynamics formulation. The simplifying assumptions include perfect axisymmetry of the rotor and gimbal structures, perfect alignment of the centers of mass of the gimbal and the rotor etc. These set of simplifying assumptions imposed on the design and dynamics of CMGs leads to adverse effects on their performance and results in high manufacturing cost. The dynamics so obtained shows the complex nonlinear coupling between the internal degrees of freedom associated with an ASCMG and the spacecraft bus's attitude motion. By default, the general ASCMG cluster can function as a Variable Speed Control Moment Gyroscope, and reduced to function in CMG mode by spinning the rotor at constant speed, and it is shown that even when operated in CMG mode, the cluster can be free from kinematic singularities. This dynamics model is then extended to include the effects of multiple ASCMGs placed in the spacecraft bus, and sufficient conditions for non-singular ASCMG cluster configurations are obtained to operate the cluster both in VSCMG and CMG modes. The general dynamics model of the ASCMG is then reduced to that of conventional VSCMGs and CMGs by imposing the standard set of simplifying assumptions used in prior literature. The adverse effects of the simplifying assumptions that lead to the complexities in conventional CMG design, and

  11. Biomedical engineering principles

    CERN Document Server

    Ritter, Arthur B; Valdevit, Antonio; Ascione, Alfred N

    2011-01-01

    Introduction: Modeling of Physiological ProcessesCell Physiology and TransportPrinciples and Biomedical Applications of HemodynamicsA Systems Approach to PhysiologyThe Cardiovascular SystemBiomedical Signal ProcessingSignal Acquisition and ProcessingTechniques for Physiological Signal ProcessingExamples of Physiological Signal ProcessingPrinciples of BiomechanicsPractical Applications of BiomechanicsBiomaterialsPrinciples of Biomedical Capstone DesignUnmet Clinical NeedsEntrepreneurship: Reasons why Most Good Designs Never Get to MarketAn Engineering Solution in Search of a Biomedical Problem

  12. Modern electronic maintenance principles

    CERN Document Server

    Garland, DJ

    2013-01-01

    Modern Electronic Maintenance Principles reviews the principles of maintaining modern, complex electronic equipment, with emphasis on preventive and corrective maintenance. Unfamiliar subjects such as the half-split method of fault location, functional diagrams, and fault finding guides are explained. This book consists of 12 chapters and begins by stressing the need for maintenance principles and discussing the problem of complexity as well as the requirements for a maintenance technician. The next chapter deals with the connection between reliability and maintenance and defines the terms fai

  13. Principles of dynamics

    CERN Document Server

    Hill, Rodney

    2013-01-01

    Principles of Dynamics presents classical dynamics primarily as an exemplar of scientific theory and method. This book is divided into three major parts concerned with gravitational theory of planetary systems; general principles of the foundations of mechanics; and general motion of a rigid body. Some of the specific topics covered are Keplerian Laws of Planetary Motion; gravitational potential and potential energy; and fields of axisymmetric bodies. The principles of work and energy, fictitious body-forces, and inertial mass are also looked into. Other specific topics examined are kinematics

  14. [Bioethics of principles].

    Science.gov (United States)

    Pérez-Soba Díez del Corral, Juan José

    2008-01-01

    Bioethics emerges about the tecnological problems of acting in human life. Emerges also the problem of the moral limits determination, because they seem exterior of this practice. The Bioethics of Principles, take his rationality of the teleological thinking, and the autonomism. These divergence manifest the epistemological fragility and the great difficulty of hmoralñ thinking. This is evident in the determination of autonomy's principle, it has not the ethical content of Kant's propose. We need a new ethic rationality with a new refelxion of new Principles whose emerges of the basic ethic experiences.

  15. Environmental Effects in Earth Rotation Data from the Large Laser-Gyroscope 'G

    Science.gov (United States)

    Gebauer, André; Schreiber, Ulrich; Klügel, Thomas

    2010-05-01

    Large laser gyroscopes allow the observation of the global rotation rate of the Earth and provide a direct reference to the instantaneous axis of rotation with high temporal resolution. This measurement method is independent and complementary to the VLBI technique, because it does not depend on external reference objects. Periodic signals from geophysical processes are analyzed in the measured datasets. Based on changes of the G ring laser hardware (see contribution Schreiber et al., this session) the instrumental sensitivity and stability improved significantly. Thus more geophysical processes both on global and local scale become visible. The time series of the measurements also contain irregular transient signals of different origin and magnitude. Several studies were carried out to identify the origin of these signals. First studies showed that the contribution of barometric loading is too small to account for the observed rotational signals. Then the effect of wind load on a local scale was studied. A detailed Finite-Element (FE) Model was developed with a dimension of about 10 km x 10 km and a minimum height of about 2 km. The topography is derived from a digital terrain model (DTM) of 25 m spatial resolution. Depending on the topography and land use the measured wind force loads the model. The results yields rotations in comparable order of magnitude as the observed ring laser data. The talk outlines the current state of ring laser data treatment.

  16. Limit of detection of a fiber optics gyroscope using a super luminescent radiation source

    CERN Document Server

    Sandoval, G E

    2003-01-01

    The main objective of this work is to establish the dependence of characteristics of the fiber optics gyroscope (FOG) with respect to the parameters of the super luminescent emission source based on doped optical fiber with rare earth elements (Super luminescent Fiber Source, SFS), argument the pumping rate election of the SFS to obtain characteristics limits of the FOG sensibility. By using this type of emission source in the FOG is recommend to use the rate when the direction of the pumping signal coincide with the super luminescent signal. The most results are the proposition and argumentation of the SFS election as emission source to be use in the FOG of the phase type. Such a decision allow to increase the characteristics of the FOG sensibility in comparison with the use of luminescent source of semiconductors emission which are extensively used in the present time. The use of emission source of the SFS type allow to come closer to the threshold of the obtained sensibility limit (detection limit) which i...

  17. Noise suppression for the differential detection in nuclear magnetic resonance gyroscope

    Science.gov (United States)

    Yang, Dan; Zhou, Binquan; Chen, LinLin; Jia, YuChen; Lu, QiLin

    2017-10-01

    The nuclear magnetic resonance gyroscope is based on spin-exchange optical pumping of noble gases to detect and measure the angular velocity of the carrier, but it would be challenging to measure the precession signal of noble gas nuclei directly. To solve the problem, the primary detection method utilizes alkali atoms, the precession of nuclear magnetization modulates the alkali atoms at the Larmor frequency of nuclei, relatively speaking, and it is easier to detect the precession signal of alkali atoms. The precession frequency of alkali atoms is detected by the rotation angle of linearly polarized probe light; and differential detection method is commonly used in NMRG in order to detect the linearly polarized light rotation angle. Thus, the detection accuracy of differential detection system will affect the sensitivity of the NMRG. For the purpose of further improvement of the sensitivity level of the NMRG, this paper focuses on the aspects of signal detection, and aims to do an error analysis as well as an experimental research of the linearly light rotation angle detection. Through the theoretical analysis and the experimental illustration, we found that the extinction ratio σ2 and DC bias are the factors that will produce detective noise in the differential detection method.

  18. Silica waveguide-type ring resonators for resonant micro-optic gyroscopes

    Science.gov (United States)

    Lin, Yi; Zhang, Jianjie; Li, Hanzhao; Ma, Huilian; Jin, Zhonghe

    2017-10-01

    The resonant micro-optic gyroscope (RMOG) is an attractive candidate for inertial rotation sensors requiring small, light and robust gyros. A high-performance RMOG needs a low-loss and high finesse waveguide-type ring resonator (WRR). Two general configurations of the WRRs which are made of Ge-doped silica core waveguides based on plasma enhanced chemical vapor deposition including the reflector-type and the transmitter-type are introduced. The reflector-type WRR with a length of 7.9 cm and a diameter of 2.5 cm has a finesse of 196.7 and a resonant depth of 98%. In addition, it's pigtailed with single-polarization fiber to reduce the polarization error. The transmitter-type WRR with a length of 15.9 cm and a diameter of 5.06 cm has a finesse of 128 and a resonant depth of 95%. The waveguide loss low as 0.007 dB/cm has been measured, leading to the shot-noise limited sensitivity of 1.0°/h when the average optical power at the input of the photodetector is 1 mW and the detecting bandwidth is 1 Hz.

  19. Eigenfrequency detecting method with sawtooth wave modulation theory for navigation grade fiber optic gyroscopes

    Science.gov (United States)

    Wang, Xiaxiao; Wang, Xiang; Yu, Jia; Zheng, Yue

    2017-09-01

    Eigenfrequency is a key parameter for the fiber optic gyroscope (FOG). An eigenfrequency detecting method for FOGs, especially for high-grade FOGs, such as the navigation grade FOGs, is proposed. The eigenfrequency is detected with the sawtooth wave modulation theory. Adjusting the frequency of the sawtooth wave to an even integer of the eigenfrequency, the error signal caused by the sawtooth wave modulation will be zero, then the eigenfrequency can be calculated by the value of the sawtooth wave frequency exactly and the bias modulation frequency is at the eigenfrequency accurately. It is demonstrated experimentally with an FOG, the length of whose sensing coil is about 1200 m, that the accuracy of the eigenfrequency measurement is better than 1.2 ppm (0.1 Hz). With its high accuracy, not only can the frequency of the bias modulation be adjusted to the eigenfrequency precisely, but also this method can be used as an eigenfrequency detector for studying the characteristics of the sensing coil according to the eigenfrequency to study the mechanism of the errors generated in the FOGs.

  20. Thermal-induced rate error of a fiber-optic gyroscope considering various defined factors

    Science.gov (United States)

    Zhang, Zhuo; Yu, Fei; Sun, Qian

    2017-09-01

    As a high-precision angular sensor, the interferometric fiber-optic gyroscope (FOG) usually shows high sensitivity to disturbances of the environmental temperature. To research the related influencing factors of influencing the thermal-induced rate error of an FOG is essential to enhance precision and environmental suitability. This paper starts with the factors neglected in past research to derive the thermal-induced error model of a fiber coil including various factors of equivalent radius, asymmetry of fiber tail, cross-layer leap, and so on in detail, and then translates this error into the inner product form of penalty factor matrix and temperature field matrix. Then, the mathematical model and the three-dimensional temperature field model of the fiber coil with the quadrupolar winding pattern is built, which includes the optic core, coating, glue, packing paper, and accurate temperature boundary conditions. The penalty factor matrix and temperature field matrix can be obtained from these models. Finally, the advancement of this revised the thermal-induced rate error model has been verified through simulation and experimental comparison.

  1. Analysis and Optimization of Dynamic Measurement Precision of Fiber Optic Gyroscope

    Directory of Open Access Journals (Sweden)

    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.

  2. High-Q microsphere resonators for angular velocity sensing in gyroscopes

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Friction moment analysis of space gyroscope bearing with ribbon cage under ultra-low oscillatory motion

    Directory of Open Access Journals (Sweden)

    Jiang Shaona

    2014-10-01

    Full Text Available This paper presents the model of calculating the total friction moment of space gyroscope ball bearings which usually work under ultra-low oscillatory motion and are very sensitive to the friction moment. The aim is to know the proportion of the friction moment caused by each frictional source in the bearing’s total friction moment, which is helpful to optimize the bearing design to deduce the friction moment. In the model, the cage dynamic equations considering six degree-of-freedom and the balls dynamic equations considering two degree-of-freedom were solved. The good trends with different loads between the measured friction moments and computational results prove that the model under constant rate was validated. The computational results show that when the speed was set at 5 r/min, the bearing’s maximum total friction moment when oscillation occurred was obviously larger than that occurred at a constant rate. At the onset of each oscillatory motion, the proportion of the friction moment caused by cage in the bearing’s total friction moment was very high, and it increased with the increasing speed. The analyses of different cage thicknesses and different clearances between cage pocket and ball show that smaller thickness and clearance were preferred.

  4. AMA- and RWE- Based Adaptive Kalman Filter for Denoising Fiber Optic Gyroscope Drift Signal.

    Science.gov (United States)

    Yang, Gongliu; Liu, Yuanyuan; Li, Ming; Song, Shunguang

    2015-10-23

    An improved double-factor adaptive Kalman filter called AMA-RWE-DFAKF is proposed to denoise fiber optic gyroscope (FOG) drift signal in both static and dynamic conditions. The first factor is Kalman gain updated by random weighting estimation (RWE) of the covariance matrix of innovation sequence at any time to ensure the lowest noise level of output, but the inertia of KF response increases in dynamic condition. To decrease the inertia, the second factor is the covariance matrix of predicted state vector adjusted by RWE only when discontinuities are detected by adaptive moving average (AMA).The AMA-RWE-DFAKF is applied for denoising FOG static and dynamic signals, its performance is compared with conventional KF (CKF), RWE-based adaptive KF with gain correction (RWE-AKFG), AMA- and RWE- based dual mode adaptive KF (AMA-RWE-DMAKF). Results of Allan variance on static signal and root mean square error (RMSE) on dynamic signal show that this proposed algorithm outperforms all the considered methods in denoising FOG signal.

  5. Classifying Step and Spin Turns Using Wireless Gyroscopes and Implications for Fall Risk Assessments

    Directory of Open Access Journals (Sweden)

    Peter C. Fino

    2015-05-01

    Full Text Available Recent studies have reported a greater prevalence of spin turns, which are more unstable than step turns, in older adults compared to young adults in laboratory settings. Currently, turning strategies can only be identified through visual observation, either in-person or through video. This paper presents two unique methods and their combination to remotely monitor turning behavior using three uniaxial gyroscopes. Five young adults performed 90° turns at slow, normal, and fast walking speeds around a variety of obstacles while instrumented with three IMUs (attached on the trunk, left and right shank. Raw data from 360 trials were analyzed. Compared to visual classification, the two IMU methods’ sensitivity/specificity to detecting spin turns were 76.1%/76.7% and 76.1%/84.4%, respectively. When the two methods were combined, the IMU had an overall 86.8% sensitivity and 92.2% specificity, with 89.4%/100% sensitivity/specificity at slow speeds. This combined method can be implemented into wireless fall prevention systems and used to identify increased use of spin turns. This method allows for longitudinal monitoring of turning strategies and allows researchers to test for potential associations between the frequency of spin turns and clinically relevant outcomes (e.g., falls in non-laboratory settings.

  6. Agent-based algorithm for fault detection and recovery of gyroscope's drift in small satellite missions

    Science.gov (United States)

    Carvajal-Godinez, Johan; Guo, Jian; Gill, Eberhard

    2017-10-01

    Failure detection, isolation, and recovery is an essential requirement of any space mission design. Several spacecraft components, especially sensors, are prone to performance deviation due to intrinsic physical effects. For that reason, innovative approaches for the treatment of faults in onboard sensors are necessary. This work introduces the concept of agent-based fault detection and recovery for sensors used in satellite attitude determination and control. Its focuses on the implementation of an algorithm for addressing linear drift bias in gyroscopes. The algorithm was implemented using an agent-based architecture that can be integrated into the satellite's onboard software. Numerical simulations were carried out to show the effectiveness of this scheme in satellite's operations. The proposed algorithm showed a reduction of up to 50% in the stabilization time for the detumbling maneuver, and also an improvement in the pointing accuracy of up to 20% when it was applied in precise payload pointing procedures. The relevance of this contribution is its added value for optimizing the launch and early operation of small satellite missions, as well as, an enabler for innovative satellite functions, for instance, optical downlink communication.

  7. Decentralized adaptive sliding mode control of a space robot actuated by control moment gyroscopes

    Directory of Open Access Journals (Sweden)

    Jia Yinghong

    2016-06-01

    Full Text Available An adaptive sliding mode control (ASMC law is proposed in decentralized scheme for trajectory tracking control of a new concept space robot. Each joint of the system is a free ball joint capable of rotating with three degrees of freedom (DOF. A cluster of control moment gyroscopes (CMGs is mounted on each link and the base to actuate the system. The modified Rodrigues parameters (MRPs are employed to describe the angular displacements, and the equations of motion are derived using Kane’s equations. The controller for each link or the base is designed separately in decentralized scheme. The unknown disturbances, inertia parameter uncertainties and nonlinear uncertainties are classified as a “lumped” matched uncertainty with unknown upper bound, and a continuous sliding mode control (SMC law is proposed, in which the control gain is tuned by the improved adaptation laws for the upper bound on norm of the uncertainty. A general amplification function is designed and incorporated in the adaptation laws to reduce the control error without conspicuously increasing the magnitude of the control input. Uniformly ultimate boundedness of the closed loop system is proved by Lyapunov’s method. Simulation results based on a three-link system verify the effectiveness of the proposed controller.

  8. A Novel Artificial Fish Swarm Algorithm for Recalibration of Fiber Optic Gyroscope Error Parameters

    Directory of Open Access Journals (Sweden)

    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.

  9. Fall-detection solution for mobile platforms using accelerometer and gyroscope data.

    Science.gov (United States)

    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.

  10. A novel artificial fish swarm algorithm for recalibration of fiber optic gyroscope error parameters.

    Science.gov (United States)

    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.

  11. A low noise interface circuit design of micro-machined gyroscope

    Science.gov (United States)

    Fu, Qiang; Di, Xipeng; Yin, Liang; Liu, Xiaowei

    2017-07-01

    The analyses of MEMS gyroscope interface circuit on thermal noise, 1/f noise and phase noise are made in this paper. A closed-loop differential driving circuit and a low-noise differential detecting circuit based on the high frequency modulation are designed to limit the noise. The interface chip is implemented in a standard 0.5 μm CMOS process. The test results show that the resolution of sensitive capacity can reach to 6.47 × 10-20 F at the bandwidth of 60 Hz. The measuring range is ± 200°/s and the nonlinearity is 310 ppm. The output noise density is 5.8^\\circ/({{h}}\\cdot \\sqrt{{Hz}}). The angular random walk (allen-variance) is 0.092^\\circ/\\sqrt{{{h}}} and the bias instability is 2.63°/h. Project supported by the National Natural Science Foundation of China (No. 61204121), the National Hi-Tech Research and Development Program of China (No. 2013AA041107), and the Fundamental Research Funds for the Central Universities (No. HIT.NSRIF.2013040).

  12. Robust trajectory tracking control of a dual-arm space robot actuated by control moment gyroscopes

    Science.gov (United States)

    Jia, Yinghong; Misra, Arun K.

    2017-08-01

    It is a new design concept to employ control moment gyroscopes (CMGs) as reactionless actuators for space robots. Such actuation has several noticeable advantages such as weak dynamical coupling and low power consumption over traditional joint motor actuation. This paper presents a robust control law for a CMG-actuated space robot in presence of system uncertainties and closed-chain constraints. The control objective is to make the manipulation variables to track the desired trajectories, and reduce the possibility of CMG saturation simultaneously. A reduced-order dynamical equation in terms of independent motion variables is derived using Kane's equations. Desired trajectories of the independent motion variables are derived by minimum-norm trajectory planning algorithm, and an adaptive sliding mode controller with improved adaptation laws is proposed to drive the independent motion variables tracking the desired trajectories. Uniformly ultimate boundedness of the closed loop system is proven using Lyapunov method. The redundancy of the full-order actual control torques is utilized to generate a null torque vector which reduces the possibility of CMG angular momentum saturation while producing no effect on the reduced-order control input. Simulation results demonstrate the effectiveness of the proposed algorithms and the advantage of weak dynamical coupling of the CMG-actuated system.

  13. Particle Filter with Novel Nonlinear Error Model for Miniature Gyroscope-Based Measurement While Drilling Navigation

    Directory of Open Access Journals (Sweden)

    Tao Li

    2016-03-01

    Full Text Available The derivation of a conventional error model for the miniature gyroscope-based measurement while drilling (MGWD system is based on the assumption that the errors of attitude are small enough so that the direction cosine matrix (DCM can be approximated or simplified by the errors of small-angle attitude. However, the simplification of the DCM would introduce errors to the navigation solutions of the MGWD system if the initial alignment cannot provide precise attitude, especially for the low-cost microelectromechanical system (MEMS sensors operated in harsh multilateral horizontal downhole drilling environments. This paper proposes a novel nonlinear error model (NNEM by the introduction of the error of DCM, and the NNEM can reduce the propagated errors under large-angle attitude error conditions. The zero velocity and zero position are the reference points and the innovations in the states estimation of particle filter (PF and Kalman filter (KF. The experimental results illustrate that the performance of PF is better than KF and the PF with NNEM can effectively restrain the errors of system states, especially for the azimuth, velocity, and height in the quasi-stationary condition.

  14. Controlling the nonlinear intracavity dynamics of large He-Ne laser gyroscopes

    CERN Document Server

    Cuccato, Davide; Belfi, Jacopo; Beverini, Nicolò; Ortolan, Antonello; Di Virgilio, Angela

    2013-01-01

    A model based on Lamb's theory of gas lasers is applied to a He-Ne ring laser gyroscope in order to estimate and remove the laser dynamics contribution from the rotation measurements. The intensities of the counter-propagating laser beams exiting one cavity mirror are continuously observed together with a monitor of the laser population inversion. These observables, once properly calibrated with a dedicated procedure, allow us to estimate cold cavity and active medium parameters driving the main part of the nonlinearities of the system. The parameters identification and noise subtraction procedure has been verified by means of a Monte Carlo study of the system, and experimentally tested on the G-Pisa ring laser oriented with the normal to the ring plane almost parallel to the Earth rotation axis. In this configuration the Earth rotation-rate provides the maximum Sagnac effect while the contribution of the orientation error is reduced at minimum. After the subtraction of laser dynamics by a Kalman filter, the ...

  15. Vibration suppression in a flexible gyroscopic system using modal coupling strategies

    Directory of Open Access Journals (Sweden)

    Sultan A. Q. Siddiqui

    1996-01-01

    Full Text Available Several recent studies have shown that vibrations in a two-degree-of-freedom system can be suppressed by using modal coupling based control techniques. This involves making the first two natural frequencies commensurable (e.g, in a ratio of 1:1 or 1:2 to establish a state of Internal Resonance (IR. When the system exhibits IR, vibrations in the two directions are strongly coupled resulting in a beat phenomenon. Upon introducing damping in one direction, oscillations in both directions can be quickly suppressed. In this paper we consider vibration suppression of a flexible two-degree-of-freedom gyroscopic system using 1:1 and 1:2 IR. The possibility of using 1:1 and 1:2 IR to enhance the coupling in the system is established analytically using the perturbation method of multiple scales. The results of IR based control strategy are compared with a new method, which is based on tuning the system parameters to make the mode shapes identical. Results indicate that this new technique is more efficient and easy to implement than IR based control strategies. Another advantage of this method is that there is no restriction on the frequencies as in the case of IR. Finally, a control torque is obtained which on application automatically tunes the system parameters to establish modal coupling.

  16. Principles Scientifiques, Principes Philosophiques

    Directory of Open Access Journals (Sweden)

    Gilles-Gaston Granger

    1999-06-01

    Full Text Available A principle is a starting point of departure as well as a rule. In science principles are either alleged evident rules or generalizations of already accepted laws, or formal determinations for objects in a given domain. Thus two problems arise: first, does their nature have a conventional character? and sencond, what kind of truth is to be assigned to them. In philosophy principles are taken as a method of thinking as well as fundamental experiences. Even though they are points of departure, their true meaning is known only after a philosophical job is done. Thus, paradoxically enough, we can say that in both science and philosophy a principle is at the same time in the begining and in the end.

  17. Vaccinology: principles and practice

    National Research Council Canada - National Science Library

    Morrow, John

    2012-01-01

    ... principles to implementation. This is an authoritative textbook that details a comprehensive and systematic approach to the science of vaccinology focusing on not only basic science, but the many stages required to commercialize...

  18. Archimedes' Principle in Action

    Science.gov (United States)

    Kires, Marian

    2007-01-01

    The conceptual understanding of Archimedes' principle can be verified in experimental procedures which determine mass and density using a floating object. This is demonstrated by simple experiments using graduated beakers. (Contains 5 figures.)

  19. Principles of applied statistics

    National Research Council Canada - National Science Library

    Cox, D. R; Donnelly, Christl A

    2011-01-01

    .... David Cox and Christl Donnelly distil decades of scientific experience into usable principles for the successful application of statistics, showing how good statistical strategy shapes every stage of an investigation...

  20. EFFECT OF MECHANICAL VIBRATION GENERATED IN OSCILLATING/VIBRATORY PLATFORM ON THE CONCENTRATION OF PLASMA BIOMARKERS AND ON THE WEIGHT IN RATS

    Science.gov (United States)

    Frederico, Éric Heleno Freire Ferreira; de Sá-Caputo, Danúbia da Cunha; Moreira-Marconi, Eloá; Guimarães, Carlos Alberto Sampaio; Cardoso, André Luiz Bandeira Dionísio; Dionello, Carla da Fontoura; Morel, Danielle Soares; Sousa-Gonçalves, Cintia Renata; Paineiras-Domingos, Laisa Liana; Cavalcanti, Rebeca Graça Costa; Asad, Nasser Ribeiro; Marin, Pedro Jesus; Bernardo-Filho, Mario

    2017-01-01

    Background: Whole body vibration (WBV) exercise has been used in health sciences. Authors have reported that changes on the concentration of plasma biomarkers could be associated with the WBV effects. The aim of this investigation is to assess the consequences of exposition of 25 Hz mechanical vibration generated in oscillating/vibratory platform (OVP) on the concentration of some plasma biomarkers and on the weight of rats. Materials and Methods: Wistar rats were divided into two groups. The animals of the Experimental Group (EG) were submitted to vibration (25 Hz) generated in an OVP with four bouts of 30 seconds with rest time of 60 seconds between the bouts. This procedure was performed daily for 12 days. The animals of the control group (CG) were not exposed to vibration. Results: Our findings show that the WBV exercise at 25 Hz was not capable to alter significantly (p<0.05) the weight of the rats. A significant alteration in the concentrations of amylase was found. Conclusion: Our results indicate a modulation of the WBV exercise with vibration of 25 Hz of frequency (i) in the pathways related to the weight and (ii) in the concentration of some biomarkers, such as amylase. PMID:28740944