Design Of Gyroscope Research Articles

Design and Vibration Sensitivity Analysis of a MEMS Tuning Fork Gyroscope with an Anchored Diamond Coupling Mechanism.

In this paper, a new micromachined tuning fork gyroscope (TFG) with an anchored diamond coupling mechanism is proposed while the mode ordering and the vibration sensitivity are also investigated. The sense-mode of the proposed TFG was optimized through use of an anchored diamond coupling spring, which enables the in-phase mode frequency to be 108.3% higher than the anti-phase one. The frequencies of the in- and anti-phase modes in the sense direction are 9799.6 Hz and 4705.3 Hz, respectively. The analytical solutions illustrate that the stiffness difference ratio of the in- and anti-phase modes is inversely proportional to the output induced by the vibration from the sense direction. Additionally, FEM simulations demonstrate that the stiffness difference ratio of the anchored diamond coupling TFG is 16.08 times larger than the direct coupling one while the vibration output is reduced by 94.1%. Consequently, the proposed new anchored diamond coupling TFG can structurally increase the stiffness difference ratio to improve the mode ordering and considerably reduce the vibration sensitivity without sacrificing the scale factor.

Nodal vibration and pattern angle error analysis of the imperfect resonators for vibratory cylinder gyroscopes

In this paper, vibration of imperfect resonators for vibratory cylinder gyroscopes is investigated. A model of the vibration based on the wave superposition is established. For an imperfect resonator, the principal stiffness axis does not coincide with the driving electrodes, so the primary mode and the secondary mode of the resonator are both excited. Superposition of these two pattern components produces the resultant pattern, which leads to a complicated vibration near the nodes and the pattern angle error. The influence of the frequency split and the driving vector orientation on the nodal vibration and the pattern angle error is particularly analyzed. Theoretical results show that the amplitude and phase of the nodal vibration are affected by the frequency split and the driving vector orientation. The pattern angle error has a positive correlation with the frequency split, and this angle also has a positive proportion with sin(8α), where α is the angle between the drive electrodes and the principal stiffness axis of the primary mode. Experiments are also included in this work to validate these influence factors. The theoretical and measured results are in close agreement. These results are useful for the mechanical balance, the electrodes assembly and the control circuit design of the cylindrical gyroscopes.

MEMS RR-type gyro with a moving electrode

A MEMS RR-type gyro design, immune to translational vibration and constant linear accelerations, is proposed. The gyro mechanical performance is improved through arranging the electrodes of the torquer and angular sensor on elastic suspension of certain stiffness. Design features of the proposed gyro are described, analytical formulas relating the natural frequencies of inertial body suspension and the electrode are given, along with the results of mathematical modeling of gyro dynamics on a vibrating foundation.

The emergence of resonance within acoustic fields of the float gyroscope suspension

The formation nature of resonance phenomena, which give rise to the rapid growth of the gyro errors in hypersonic flight conditions in the suspension of a two-stage float gyroscope is revealed. On the example of the industrial design of the float gyroscope, computational models are built. They allowed determining the influence of the antisymmetric and symmetric impedance of the housing on the emergence of resonance conditions in the suspension. The influence of the propagation direction of acoustic radiation on the occurrence of the features, leading to the rapid growth of additional autonomous positioning errors is determined. The resonance content at high (above the cutoff) and low (below the cutoff) frequencies is revealed. It is shown that at high frequencies the resonance is formed by only bending vibration of the housing in the sound field provided that the antisymmetric impedance is much lower than the symmetrical impedance. It is found that the low-frequency resonance can be formed only by the circumferential vibration of the housing depending on the sound wave incidence angles. It appears in the form of the wave coincidence of the trace of the incident and circumferential waves, or coincidence of the circumference of the frame and the circumferential wave on the plane of the incident wavefront. The resonance methods of dealing with the influence of the sound fields as the only effective ones in the resonance conditions of hypersonic flight are analyzed.

Micro-clamps for precise positioning of 120° silicon double mirrors in a MOEMS gyroscope

Micro-silicon double mirrors have been developed specifically for the design of a novel micro-optical gyroscope. By using wafers with a well-defined angular offset to the (100) plane, an etching angle of 60° can be achieved by wet-chemical etching with KOH. Two likewise structured wafers are connected by means of silicon direct bonding and consequently form 120° double mirrors. A big advantage of these double mirrors is that inaccuracies during assembly onto a micro-optical table, such as shifts in the x- and y-direction and twists around the vertical axis are compensated by the mirror and a fixed angle of reflection is maintained. Assembly tolerances for the other two rotational degrees of freedom cannot be compensated in this way yet and a precise rotational alignment of the mirror elements in an optical resonator is still required. Therefore a micro-clamping device was developed that can be used in the assembly of a micro-optical gyroscope. The key elements are micro-spring structures integrated in the micro-optical table which can be pushed back to allow the insertion of the mirror elements and press the mirrors against two lithographically defined mechanical stops. Various designs of clamping devices were fabricated and their suitability in an optical gyroscope was evaluated.

Design and optimization of a resonant output frequency gyroscope for robust sensitivity and bandwidth performance

This paper presents the architecture and optimization verification of a designed mode-mismatching gyroscope prototype made with fused silica in atmospheric pressure. The gyroscope prototype uses the decoupling frame and double-ended tuning fork (DETF) to achieve high sensitivity and quality factor. This structure can suppress residual quadrature error due to fabrication errors and imperfections. The angle rate-sensitive elements of the proposed gyroscope prototype with quasi-digital FM output are two DETF resonators resulting in differential implementation. We describe the principle of operation characterization of our micromechanical vibratory rate gyroscope based on resonant sensing of the Coriolis force and establish mathematical model called multi-parameters excitation system dynamics of Mathieu equation based on our previous work. We specify and quantify the impact functions of mechanical parameters on the properties of gyroscopes and identify sensitivity and limitation of sensitivity and bandwidth each other. A sample-based stochastic model is established to investigate the influence of different uncertain structure size on gyroscope performance. According to the uncertainty analysis, we modify the previous gyroscope structure, and then the parameters and structure of the improved third version gyroscope are obtained. This research can provide a reference for design and optimization of the structure size to improve robustness and performance of resonant angle rate sensor.

A Compiler Based Approach for Design and Analysis of Gyroscopes

A Compiler Based Approach for Design and Analysis of Gyroscopes

A Simple, Full-Dynamic-Range Optical Heterodyne Single-Mode Fiber Gyroscope

In this study, a theoretical design of a simple fiber-optic gyroscope is proposed. This fiber-optic gyroscope not only realizes the full-dynamic-range of Sagnac-phase measurement, but also eliminates the excess phase affected by the elliptical birefringence of a single-mode fiber coil. Under the conditions that the fiber coil has 1100 turns and the fiber length is 242.9 m, the bias stability of this gyroscope is theoretically evaluated as 9.44 °/h. In this study, we also discuss the error signal that arises from the intensity stability, as well as the polarization nonreciprocity. We generate 1000 random values to simulate the possible distribution of a bias drift, and the result shows that the drift of the Sagnac phase is less than 10 $^{-3{\circ}}$ . In addition, we deduce the influence of the error signal induced by polarization nonreciprocity. The result indicates that the maximum error arises if the reciprocal phase of the SMF is $\varphi = 2m\pi $ ( $m = 0, \pm 1, \pm 2, \pm 3,\ldots$ ) and the optical rotation angle is $\theta = 45^{\circ}$ .

Study of a Novel Micro-mechanical Gyroscope using for Rotation Carrier

In this paper, a novel silicon micro-machined gyroscope is introduced, which is driven by the rotating carrier’s angular velocity. The principle of structure is analyzed .The mathematic module is also established and the dynamics parameters of the gyroscope is calculated, Design and analysis of signal processing circuit, design and processing of the gyroscope sensing head, at last, the gyroscope is tested, the test results and the theoretical analysis is consistent。

Impact study of anisotropic optical fibers winding with different tension value on the H-parameter invariance degree

Subject of Research. We have investigated the effect of anisotropic optical fibers winding with an elliptical sheath subjecting to stress on the H-parameter invariance degree. This type of optical fiber is used in the manufacture of fiber loop in fiber-optic gyroscopes. Method of Research. The method of research is based on the application of Michelson polarization scanning interferometer as a measuring device. Superluminescent diode with a central wavelength of 1575 nm and a half-width of the spectrum equal to 45 nm is used as a radiation source. The studies were carried out with anisotropic optical fiber with 50 m long elliptical sheath subjecting to stress. The fiber was wound with one layer turn to turn on the coil with a diameter of 18 cm, which is used in the design of fiber-optic gyroscope. The tension force of the optical fiber was controlled during winding on a special machine. Main Results. It was found that at the increase of tension force from 0.05 N to 0.8 H the value of H -parameter increases from 7×10-6 1/m up to 178×10-6 1/m, respectively; i.e. the coupling coefficient of orthogonal modes in the test fiber is being increased. Thus, it is necessary to consider the longitudinal tension force of fiber in the design and manufacture of the fiber-optic sensors of high accuracy class: the less the fiber winding power, the higher invariance degree of distributed H -parameter. The longitudinal tension force of anisotropic optical fiber with elliptical sheath subjecting to stress equal to 0.2 N is recommended in the process of designing fiber-optic gyroscopes. Practical Relevance. The proposed method of Michelson scanning interferometer is usable in the production process for quality determination of the optical fiber winding: no local defects, value controlling of fiber H -parameter.

Vibration Control of a Column Using a Gyroscope

Inthispaper, the characteristics of a vibration control system utilizing a gyro and its effectiveness in the control of the motion subjected to a seismic ground motion acceleration were studied. A gyro design was presented as a vibration absorber for reduction of the column vibration, which has a potential for application to towers, high-rise buildings and other structures.Thenon-linear motions of the gyro-column system and the equations of motion for the system are derived following energy (Lagrange) based approaches and examples provided. On the otherhand, the effect of the angular velocity of thegyroscope is studied, and it is shown that the angular velocity (spin velocity) Ω of gyroscope has a significant effect on the behavior of the dynamic motion.It is also shown how the damper and spring due to the motion between the suporting gimbaland tip mass influence the dynamic behavior of the gyroscope.

Enhancing the mechanical resistance of micromechanical gyros

The paper considers the methods improving the mechanical resistance of MEMS gyros. A multi-aspect classification is proposed for systematizing data on mechanical performance of various gyro designs, and new perspective design principles are considered.

Research on a Micro Piezoelectric Gyroscope with Concentrated Rocking‐Mass

This study introduces a Micro Electro Mechanical Systems (MEMS) piezoelectric gyroscope with a concentrated rocking‐mass, made from PZT ceramic. The gyroscope operates in the rocking mode with a frequency of 91.3 kHz. This gyroscope follows the study of the MEMS piezoelectric BAW gyroscope with an improvement of fewer boundary constraints, which enhances the device's operability and characteristic. Through the MEMS fabrication process, the device with a side of length 12 mm achieves a rate sensitivity of 30.7 μV/°/s and a bias stability of 8.6°/s. This study describes the design, fabrication, circuit system, and characteristics of this micro piezoelectric gyroscope.

Parametric design of mechanical dither with bimorph piezoelectric actuator for ring laser gyroscope

This paper presents a mathematical model and a finite element model to investigate the model parameters of me- chanical dither in a ring laser gyroscope in which the bimorph piezoelectric actuator are employed as driving mechanisms to avoid the problem of so-called lock-in effects. The validity and efficiency of the mathematical model and finite element model are conformed by comparing with the sinusoidal experimental results, and the errors are 3.14% and 1.79% respectively. Moreover, the parametric design for the geometric dimensions of mechanical dither and the bimorph piezoelectric actuators is easily achieved through finite element model. It is shown that careful selection of the structural parameters allows the resonant frequency to be suitable. These results are important for the mechanical dither design and improvement of high accuracy ring laser gyroscopes and inertial navigation system.

Design and vibration sensitivity of a MEMS tuning fork gyroscope with anchored coupling mechanism

In this paper, a novel MEMS tuning fork gyroscope with anchored coupling mechanism is designed to analyze the mode ordering and vibration sensitivity. The proposed TFG prioritizes anti-phase drive-mode by using a levered mechanism while the sense-mode is prioritized utilizing an anchored coupling ring spring linked by four linear beams, which eliminates the lower frequency parasitic mode and provides true mechanical suppression of external vibration. In order to make a contrast with the proposed novel anchored coupling TFG, a conventional one with a direct coupling ring spring between two tines is also designed. The simulated frequencies of the in-phase and anti-phase in the sense mode are 4,006.8 and 4,463.5 Hz, respectively. Meanwhile, the in-phase frequency of the anchored coupling TFG is 5,958.4 Hz, improving by 48.7 %, and the anti-phase frequency is increased a little. Additionally, we carry out the FEM simulations on the vibration sensitivity induced by the stiffness imbalance for the two types of TFGs. Our results demonstrate that the vibration output is reduced by 74.8 and 88.1 % in the anti-phase mode and in-phase mode, respectively. Therefore, the novel anchored coupling TFG can provide improved mode ordering and substantially suppress the vibration output without compromising the scale factor.

A Novel Design of Fiber Optic Gyroscope Based INS System for UAS Applications

This paper describes an inertial navigation system (INS) for autonomous quad copter application, based on Fiber Optic Gyroscopes (FOG). As the FOG lack the mechanical components of the age old traditional Gyroscopes, they show good performance in terms of weight, size, sensitivity, robustness and resistance to physical forces. These characteristics make a FOG very efficient and extremely useful in strap down altitude navigational systems using heading reference. In this paper, an effort has been made to design and test run an INS based on FOG, which tries to satisfy the generic positioning requirements for typical UAS applications. The paper also cover lab-evaluations of testing the response of the system based on several test cases which also include errors owing from alignment and those induced by the sensor itself. Simulation results suggest good performance of the test system developed. Detailed results of system simulation are also reproduced.

Design and fabrication of a novel tri-axis gyroscope with sensing diagonal-pendulums

In this paper, we present a novel design of tri-axis gyroscope which consists of two diagonal-pendulum masses for lateral sensing, coupled with and enclosed in a traditional tuning fork driving frame. The diagonal-pendulums are driven to swing via tilted transforming beams as the driving frame oscillated in plane, and rotate around their torsional beam out-of-plane as orthogonal lateral angular rate applied. The symmetric arrangement of whole structure lowers mechanical complexity and the sensing way of "one diagonal-pendulum for one lateral axis" eliminates sensing proof mass sharing which can effectively suppress the cross-talk effect. The prototype device has been successfully fabricated by using SOI-based bulk micromachining processes and vacuum packaged by Al---Ge eutectic bonding. The sensitivities for three axes are 4.83, 1.47 and 1.38 mV/(°/s), respectively, with nonlinearity of less 1 % and bandwidth of above 600 Hz.

New design architecture of a 3-DOF vibratory gyroscope with robust drive operation mode and implementation

This paper presents new gyroscope design architecture with the complete 2-DOF drive and 1-DOF sense mode oscillators that enable the implementation of reduced drive bandwidth without significantly decreasing the sense-to-drive mass ratio of the device. The mechanical structure has an additional anchoring of the decoupling frame mass which allows for the specification of the drive mode resonances and the coupling between the masses independent of the sense mode frequency. This feature eliminates the requirement of an increased design space for realizing a high operational frequency device with robust operation. In addition to this, a reduction in the bandwidth enabled by the additional anchor, leads to the increase in drive mass amplitude, which in turn results in an increased mechanical gain. With this arrangement, the actuation voltage can be further reduced for the same drive displacement as of non-anchored structure. This device has been mathematically modelled considering decoupled frame anchoring effect, designed and then fabricated by using the economical UV-LIGA technology with nickel as a key structural layer of 8 µm thickness; with an overall reduced key structure size of 2.13 by 1.93 mm. Experimental characterization demonstrates the two drive resonances at 8.55 and 10.6 kHz with a bandwidth of 1.0 kHz and the sense mode resonance at 9.2 kHz.

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

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 ~103; 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.

A MEMS piezoelectric solid disk gyroscope with improved sensitivity

This paper introduces a MEMS piezoelectric solid disk gyroscope. The gyroscope operates in an in-plane elliptic bulk acoustic wave mode with a frequency of 284 kHz. This gyroscope is an improvement of the solid piezoelectric gyroscope. A device, 6 mm in diameter, has been fabricated through the microelectromechanical systems process, and achieved a relatively high sensitivity and bias instability. In this paper, it is described that the design, fabrication, circuit system and characteristics of the piezoelectric solid disk gyroscope.