Performance Of Gyroscope Research Articles

Identification and correction of phase delay errors for hemispherical resonator gyroscopes

The phase-delay error of the circuit system is the primary source of the output error observed in the hemispherical resonator gyroscope (HRG). Additionally, the temperature-dependent nature of the phase-delay error results in a deterioration of the initial calibration parameters, which, in turn, significantly impairs the performance of the gyroscope in its intended application. This paper proposes a self-calibration method to effectively suppress the impact of phase-delay error on the application performance of gyroscopes. Firstly, based on the analysis of the influence of phase-delay error on the performance of the whole-angle mode HRG, a sinusoidal interference signal with a small amplitude is introduced into the quadrature control loop of the gyroscope. Then, the angular rate signal is demodulated and calculated to obtain the phase-delay error of the system, which is employed as the compensation value of the reference phase of the PLL to offset the phase-delay error of the circuit system in real-time. The experimental results demonstrate that after the phase-delay error is self-calibrated, the zero-bias output error of the gyroscope is reduced by 5 times, the bias instability is improved by 37.7%, and the self-calibration method of the phase-delay error presented is more strongly robust to temperature changes.

Research on the control method to improve the dynamic performance of high-precision fiber optic gyroscope

Research on the control method to improve the dynamic performance of high-precision fiber optic gyroscope

Innovative Modeling of IMU Arrays Under the Generic Multi-Sensor Integration Strategy.

This research proposes a novel modeling method for integrating IMU arrays into multi-sensor kinematic positioning/navigation systems. This method characterizes sensor errors (biases/scale factor errors) for each IMU in an IMU array, leveraging the novel Generic Multisensor Integration Strategy (GMIS) and the framework for comprehensive error analysis in Discrete Kalman filtering developed through the authors' previous research. This work enables the time-varying estimation of all individual sensor errors for an IMU array, as well as rigorous fault detection and exclusion for outlying measurements from all constituent sensors. This research explores the feasibility of applying Variance Component Estimation (VCE) to IMU array data, using separate variance components to characterize the performance of each IMU's gyroscopes and accelerometers. This analysis is only made possible by directly modeling IMU inertial measurements under the GMIS. A real land-vehicle kinematic dataset was used to demonstrate the proposed technique. The a posteriori positioning/attitude standard deviations were compared between multi-IMU and single IMU solutions, with the multi-IMU solution providing an average accuracy improvement of ca. 14-16% in the estimated position, 30% in the estimated roll and pitch, and 40% in the estimated heading. The results of this research demonstrate that IMUs in an array do not generally exhibit homogeneous behavior, even when using the same model of tactical-grade MEMS IMU. Furthermore, VCE was used to compare the performance of three IMU sensors, which is not possible under other IMU array data fusion techniques. This research lays the groundwork for the future evaluation of IMU array sensor configurations.

Improve the performance of MEMS gyroscope by combination of virtual gyroscope and improved Sage-Husa adaptive filtering algorithm

Improve the performance of MEMS gyroscope by combination of virtual gyroscope and improved Sage-Husa adaptive filtering algorithm

Nonlinear performance enhancement of imperfect ring-based Coriolis Vibratory Gyroscopes

Abstract The rate sensing performance of ring-based capacitive Coriolis Vibratory Gyroscopes (CVGs) is susceptible to the effects of imperfections and electrostatic nonlinearities. This research investigates the use of the nonlinear electrostatic forces to nullify these effects and replicate linear and trimmed sensor performance at increased vibration amplitudes. The approach used involves applying a suitable voltage distribution to modify the mechanical sensing mode, and a mathematical model is used to demonstrate the implementation of this scheme. For the case of 8 evenly distributed electrodes, a balancing voltage component is introduced to counteract the net forces stemming from the imperfection-induced quadrature coupling and the nonlinear frequency imbalance. The effects of the implementation are demonstrated in terms of improvements to rate sensitivity, bias rate and quadrature error of the device mechanical output. Finite element results are also included to validate the potential of this force balancing scheme. It is shown that the proposed scheme enhances device performance by reducing the bias rate and mechanical quadrature response to negligible levels and increasing rate sensitivity at increased drive amplitudes.

Range Expansion Technology for Ring MEMS Gyroscopes Based on Drive Voltage Modulation.

This paper proposes a method to control the sensitivity of a ring MEMS gyroscope by adjusting the driving control voltage via MEMS. The aim is to explore the relationship between the range of the ring MEMS gyroscope and the driving control voltage, establishing a mathematical model that correlates driving control voltage with sensitivity. By applying different driving voltages to the same gyroscope, the study evaluates the performance and range of the gyroscope. Experimental results demonstrate that lower driving voltages increase the gyroscope's range. At a driving voltage of 10.85 V, the gyroscope achieves a range of ±200°/s, a minimum resolution of 0.019°/s, and a nonlinearity of 22.37 ppm. At 1.46 V, the gyroscope range expands to ±1000°/s, with a minimum resolution of 0.05138°/s and a nonlinearity of 60.73 ppm. As the measurement range increased fivefold, the degradation in gyroscope performance was significantly less than the scale of range expansion. Compared to the gain in modulation detection circuitry, gyroscope performance was optimized across the entire operational range.

Multi-Frame Vibration MEMS Gyroscope Temperature Compensation Based on Combined GWO-VMD-TCN-LSTM Algorithm.

This paper presents a temperature compensation model for the Multi-Frame Vibration MEMS Gyroscope (DMFVMG) based on Grey Wolf Optimization Variational Mode Decomposition (GWO-VMD) for denoising and a combination of the Temporal Convolutional Network (TCN) and the Long Short-Term Memory (LSTM) network for temperature drift prediction. Initially, the gyroscope output signal was denoised using GWO-VMD, retaining the useful signal components and eliminating noise. Subsequently, the denoised signal was utilized to predict temperature drift using the TCN-LSTM model. The experimental results demonstrate that the compensation model significantly enhanced the gyroscope's performance across various temperatures, reducing the rate random wander from 102.929°/h/√Hz to 17.6903°/h/√Hz and the bias instability from 63.70°/h to 1.38°/h, with reductions of 82.81% and 97.83%, respectively. This study validates the effectiveness and superiority of the proposed temperature compensation model.

Sensitivity improvement of the closed-loop resonant fiber-optic gyroscope interrogated with a broadband source

The resonant fiber-optic gyroscope (RFOG), interrogated with a broadband light source, represents an intriguing optical gyroscope that has been proposed as an extension of the traditional RFOG, which is driven by a narrow linewidth laser source. The implementation of a closed-loop detection system enhances the linearity and dynamic range of the gyroscope output. This paper is devoted to improving the sensitivity of the closed-loop broadband source-driven RFOG. First, a model for analysis and optimization of the feedback loop gain of a closed-loop broadband source-driven resonant fiber-optic gyroscope (RFOG) is developed, and the feedback loop gain is optimized. The experimental results indicate that the influence of the feedback loop noise on the gyro performance can be neglected. Subsequently, the noise contributions, including the shot noise, detector noise, and relative intensity noise, in the broadband source-driven RFOG system are investigated. A theoretical derivation and experimental verification of an expression for the reduction of the relative intensity noise by a fiber-optic ring resonator are presented. Finally, a packaged broadband source-driven RFOG prototype using a 175 m long fiber coil with an average diameter of 5.7 cm was constructed and evaluated. The experimental results demonstrate that the prototype achieves navigation-grade precision with an angular random walk of 0.003∘/h1/2 and a bias instability of 0.005°/h.

Noise Analysis and Suppression Methods for the Front-End Readout Circuit of a Microelectromechanical Systems Gyroscope

Circuit noise is a critical factor that affects the performances of an MEMS gyroscope. Therefore, it is essential to analyze and suppress the noises in the key analog circuits, which are the main noise sources. This study presents an optimized front-end readout circuit and noise suppression methods. First, the noise analysis of the front-end readout circuit is carried out with theoretical derivation to clarify the main noise contributors. To suppress the output noise, an improved readout circuit based on the T-resistor networks is proposed, and the corresponding noise equation is derived in detail. In addition, the noise analysis of the critical circuits of the detection and control system, such as the inverting amplifiers, the first-order low-pass filters, and the first-order high-pass filters, is carried out, and the noise suppression strategy with the optimization of the resistances and is proposed. Taking the inverting amplifier as an example, the theoretical derivation is verified by measuring and comparing the output noises of different resistance schemes. In addition, the output noises of the gyroscope before and after circuit optimization are measured. Experimental results demonstrate that the output noise with the circuit optimization is reduced from 60 μV/Hz1/2 to 30 μV/Hz1/2 and the bias instability is reduced from 3.8 deg/h to 1.38 deg/h. In addition, the ARW is significantly improved from 0.035 deg/h1/2 to 0.018 deg/h1/2, which indicates that the proposed noise analysis and suppression methods are effective and feasible.

Mitigating rim bending in fused silica micro shell resonators by a chamfered mold

In this work, we addressed the bending of a micro shell resonator’s rim toward the stem during glass-blowing process. This phenomenon occurs due to increased heat loss at the mold’s edge and reduced heat flux at the side of the Gaussian heat source. To mitigate rim bending and the subsequent reduction in capacitance between the rim and 3D electrodes, which can degrade performance in micro glass-blown shell resonators for gyroscopes, we propose two potential mold solutions, using short-stem mold and chamfered mold. To quantitatively compare resonators created by these two types of molds, we calculated the noise factor for predicting its gyroscope performance. From these calculations, we find out that using the chamfered mold enables us to increase in the resonator’s effective mass, eigenfrequency, angular gain, and quality factor, consequently reducing the noise factor compared to using the short-stem mold. We also demonstrated these results by manufacturing shell resonators and measuring its vibrational characteristics. After metalization of the glass shell resonator, Q factor and eigen frequency of n = 2 vibration mode along the primary (secondary) axis were measured to 622,466 ± 6,427 (619,793 ± 6,402) and 4,343 ± 40 Hz (4,350 ± 40 Hz), respectively. This simulation process will assist us in getting insight into understanding a shell resonator as a gyroscope, designing a mold and determining experimental conditions.

Low-Damage Trimming of Micro Hemispherical Resonators by Chemical Etching.

To enhance the performance of micro-hemispherical gyroscopes, achieving low-damage and high-surface-quality trimming is essential. This enables greater stability and reliability for the gyroscopes. Current methods for reducing frequency split often come with drawbacks such as high cost, adverse effects on the Q-factor, or surface damage. In this paper, a chemical etching trimming method is proposed to reduce frequency split in micro-hemispherical resonators. This method allows for trimming with minimal damage, while also being cost-effective and easy to implement. The theoretical basis of this method was analyzed, followed by a simulation to determine the optimal trimming range and location on the resonator. The simulated Q-factor analysis before and after trimming preliminarily validated the method's low-damage characteristics. Ultimately, the frequency split of the resonator was reduced to below 1 Hz. Additionally, test results of the Q-factor and surface quality before and after trimming further confirmed that chemical etching offers effective low-damage trimming capabilities. The proposed method holds significant potential for improving the performance of micro-hemispherical resonator gyroscopes.

4H silicon carbide bulk acoustic wave gyroscope with ultra-high Q-factor for on-chip inertial navigation

Inertial navigation on a chip has long been constrained by the noise and stability issues of micromechanical Coriolis gyroscopes, as silicon, the dominant material for microelectromechanical system devices, has reached the physical limits of its material properties. To address these challenges, this study explores silicon carbide, specifically its monocrystalline 4H polytype, as a substrate to improve gyroscope performance due to its low phonon Akhiezer dissipation and its isotropic hexagonal crystal lattice. We report on low-noise electrostatic acoustic resonant gyroscopes with mechanical quality factors exceeding several millions, fabricated on bonded 4H silicon carbide-on-insulator wafers. These gyroscopes operate using megahertz frequency bulk acoustic wave modes for large open-loop bandwidth and are tuned electrostatically using capacitive transducers created by wafer-level deep reactive ion etching. Experimental results show these gyroscopes achieve superior performance under various conditions and demonstrate higher quality factors at increased temperatures, enabling enhanced performance in an ovenized or high-temperature stabilized configuration.

Design and analysis of mode-matched decoupled mass MEMS gyroscope with improved thermal stability

This paper presents an efficient design approach for microelectromechanical systems (MEMS) gyroscope considering the design constraint of MEMSCAP’s Silicon-on-Insulator Multi-User MEMS Processes (SOIMUMPs). A design for a decoupled mass MEMS resonant gyroscope with tuning electrodes is presented to minimize cross-axis coupling and optimize the gyroscope’s performance. The device features a size of 1.8 ×2.772 mm2 . A decoupled mass MEMS gyroscope has been designed using a novel mechanical beam configuration that optimizes the structural design to reduce unwanted interactions between drive and sense axes motions. Mode order has been achieved by obtaining the first two modes as drive and sense modes at 9946.3 Hz and 10 202.7 Hz, respectively. Parallel plate electrostatic tuning electrodes have been added to adjust and match the drive and sense modes at the resonant frequencies of 9946 Hz. This mode matching is crucial for optimizing gyroscope performance, accuracy, and sensitivity. The effects of temperature variation on the performance of the designed decoupled mass MEMS gyroscope have been investigated, particularly in terms of its mode-matched operation achieved using tuning electrodes. Finite element method (FEM) simulations were conducted, demonstrating that thermal stability was achieved, and mode-matched operation was maintained within the temperature range of −40 °C to 80 °C. The gyroscope exhibits enhanced performance compared to existing MEMS gyroscopes under mode-matched conditions, featuring a lower temperature coefficient of frequency (TCF) at 0.0415 Hz °C−1 in the drive mode and 0.0165 Hz °C−1 in the sense mode. FEM analysis for the fabrication process tolerances has been done, where MEMS gyroscope’s resonant frequencies, output capacitance, output displacement, and sense mode quality factor have shown negligible changes to fabrication process tolerances. Transient analysis was conducted using CoventorWare MEMS+ 3D schematic, which was integrated with MATLAB Simulink to measure the MEMS gyroscope’s output response, which corresponded with the varying input angular velocity signal.

Influence of the average wavelength on the scale factor stability of interferometric fiber optic gyroscope

The introduction of closed-loop mechanisms has significantly enhanced the performance of interferometric fiber optic gyroscopes (IFOGs). However, the poor scale factor (SF) stability limits its further application due to the use of broadband light sources. This study first reviewed the impact of the average wavelength of a light source on SF stability in a closed-loop IFOG setup. A simulation model is developed according to modulation and demodulation principles, and the SF error is found to be proportional to the wavelength drift in a closed-loop IFOG. Additionally, employing a laser with a more stable average wavelength instead of a super fluorescent fiber source (SFS) for driving the IFOG enhanced the SF stability by an order of magnitude to 0.38 ppm in ambient-air experiments, which is one of the best SF performances achieved thus far. With the significant improvement in stability during the variable temperature tests, the IFOG measures rotation rates more accurately.

Design of an integrable double-sided optoplasmonic gyroscope via a bent hybrid structure

This paper presents an optoplasmonic gyroscope that employs a novel bent-hybrid structure, and works double-sided. The proposed device is integrable without moving parts, and simply has a robust configuration. The detection mechanism is based on surface plasmon polaritons (SPPs), and the sensor consists of a laser, a bent-metal layer, and a photo-detector (PD). Based on the simulations, the proposed gyroscope provides significant characteristics of a measurement range of ± 45000°/s, an optical sensitivity of 6.025 µ/(°/s), a total sensitivity of 2.41 µA/W(°/s), an ultra-high resolution ability of 16.598 µ°/s, and an accuracy of 99.999%. The dimensions are 5 × 5 × 5 µm3, and the measurement time is 1 ms. The operational wavelength is at visible range of λ = 630 nm. Additionally, the effects of various parameters, including metal material, metal thickness, and laser wavelength, on the gyroscope performance are comprehensively studied.

A toroidal SAW gyroscope with focused IDTs for sensitivity enhancement

A surface acoustic wave (SAW) gyroscope measures the rate of rotational angular velocity by exploiting a phenomenon known as the SAW gyroscope effect. Such a gyroscope is a great candidate for application in harsh environments because of the simplification of the suspension vibration mechanism necessary for traditional microelectromechanical system (MEMS) gyroscopes. Here, for the first time, we propose a novel toroidal standing-wave-mode SAW gyroscope using focused interdigitated transducers (FIDTs). Unlike traditional SAW gyroscopes that use linear IDTs to generate surface acoustic waves, which cause beam deflection and result in energy dissipation, this study uses FIDTs to concentrate the SAW energy based on structural features, resulting in better focusing performance and increased SAW amplitude. The experimental results reveal that the sensitivity of the structure is 1.51 µV/(°/s), and the bias instability is 0.77°/s, which are improved by an order of magnitude compared to those of a traditional SAW gyroscope. Thus, the FIDT component can enhance the performance of the SAW gyroscope, demonstrating its superiority for angular velocity measurements. This work provides new insights into improving the sensitivity and performance of SAW gyroscopes.

An Adaptive Multi-Population Approach for Sphericity Error Evaluation in the Manufacture of Hemispherical Shell Resonators.

The performance of a hemispherical resonant gyroscope (HRG) is directly affected by the sphericity error of the thin-walled spherical shell of the hemispherical shell resonator (HSR). In the production process of the HSRs, high-speed, high-accuracy, and high-robustness requirements are necessary for evaluating sphericity errors. We designed a sphericity error evaluation method based on the minimum zone criterion with an adaptive number of subpopulations. The method utilizes the global optimal solution and the subpopulations' optimal solution to guide the search, initializes the subpopulations through clustering, and dynamically eliminates inferior subpopulations. Simulation experiments demonstrate that the algorithm exhibits excellent evaluation accuracy when processing simulation datasets with different sphericity errors, radii, and numbers of sampling points. The uncertainty of the results reached the order of 10-9 mm. When processing up to 6000 simulation datasets, the algorithm's solution deviation from the ideal sphericity error remained around -3 × 10-9 mm. And the sphericity error evaluation was completed within 1 s on average. Additionally, comparison experiments further confirmed the evaluation accuracy of the algorithm. In the HSR sample measurement experiments, our algorithm improved the sphericity error assessment accuracy of the HSR's inner and outer contour sampling datasets by 17% and 4%, compared with the results given by the coordinate measuring machine. The experiment results demonstrated that the algorithm meets the requirements of sphericity error assessment in the manufacturing process of the HSRs and has the potential to be widely used in the future.

Gyroscopic precession control for maneuvering two‐wheeled robot recoil stabilization

AbstractA two‐wheeled robot has high maneuverability and can spin around with a high velocity but is prone to roll over under a recoil force. Because the wheels are only used to control the maneuver speed of the robot. However, a two‐wheeled robot using a gyroscope does not need the control of the wheels and can maintain the stability of the robot under a recoil force during maneuvers even if the gimbal of the gyroscope is not controlled by a torque. In this study, the equations of motion of the gyroscopic robot are derived via Lagrangian equations, and the balancing performance of the uncontrolled gyroscope is simulated via Matlab to determine a desired configuration for mechatronics system design. Then, a linear‐quadratic regulator (LQR) is implemented to the chosen control moment gyroscope (CMG) configuration and compared in simulations of RecurDyn. LQR controller was used to prevent oscillating motions of double CMGs under the recoil force of a weapon. The simulation results showed that the gyroscopic two‐wheeled robot is improved using an LQR controller and powerfully balanced in static with excellent performance.

Separation of mass and gap errors of hemispherical resonator gyroscopes by varying bias voltage

For hemispherical resonator gyroscopes (HRGs), mass imperfections and capacitive gap nonuniformity jointly influence the frequency mismatch and degrade the gyroscope performance. However, the coupling mechanism and separation of these two errors are rarely discussed. This paper proposes, for the first time, a novel method of separating mass imperfections and gap nonuniformity of HRGs, based on a dynamics model considering both the two errors. By measuring the frequency mismatches and principal axes of stiffness at different bias voltages, the mass imperfections and gap nonuniformity can be separately obtained. The method is investigated in detail by simulation, and validated by experiment on three different HRGs. The experimental results agree well with the theoretical analysis, demonstrating the effectiveness of the model and the separation method. Our method may contribute to high-precision HRG manufacture, and can be conveniently applied to other Coriolis vibrating gyroscopes (CVGs) with electrostatic actuation.

Low-cost MEMS gyroscope performance improvement under unknown disturbances through deep learning-based array

The performance of low-cost Micro Electro Mechanical systems (MEMS) gyroscope severely deteriorates under unknown disturbances, such as temperature, vibration and shock. In this paper, gyroscope array based on deep learning is proposed to improve the accuracy of single gyroscope during unknown disturbances. First, the gyroscope raw data are subjected to modeling and estimation within long short-term memory (LSTM) neural network. By training the model within the LSTM network, the intricate patterns and dynamic variations present in the gyroscope data could be captured, resulting in the generation of high-quality state estimates. Furthermore, the dropout technique is introduced to finely adjust the LSTM model, with the aim of reducing overfitting risks and effectively diminishing the computational complexity of the network. Lastly, state estimates generated by the LSTM are ingeniously combined with the raw gyroscope observations, furnishing the Kalman filter (KF) with input. The simulation and experiment results demonstrate that compared with the gyroscope array based on KF and H∞, the proposed method exhibits better performance and robustness.