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.
With the rapid advancements in inertial technology and Micro-Electro-Mechanical System (MEMS) fabrication, MEMS gyroscopes have gained widespread use across various industries. To address the ...problems of bad temperature stability and high noise in MEMS gyroscopes, this paper proposes a novel fusion algorithm based on the double U-beam vibration ring gyroscope (DUVRG), which incorporates temperature compensation and noise suppression. The proposed algorithm constructs a gyro temperature error model using a signal extraction method based on quantized temperature. Noise suppression is achieved by integrating a Kalman filter (KF) and a statistical calibration filter (SCF) based on an adaptive sliding window (ASW). After three sets of temperature experiments with different temperature change rates, the compensated experimental results show that the gyro angular random walk (ARW) is reduced to 0.58°/√h and the bias instability (BI) is reduced to 1.10°/h in the range of -40°C to 60°C. Compared with the original signals, the ARW and BI are reduced by 71.8% and 98.8%, respectively. The proposed novel temperature compensation and noise suppression method effectively enhances the temperature stability and noise performance of the gyroscope. Furthermore, this fusion algorithm requires less computational resources and satisfies the requirements of real-time signal processing, distinguishing it from conventional algorithms.
Toward the objective of direct angle measurement using a rate integrating gyroscope (RIG) without a minimum rate threshold and with performance limited only by electrical and mechanical thermal ...noise, in this paper, we present the implementation of a generalized electronic feedback method for the compensation of MEMS gyroscope damping asymmetry (anisodamping) and stiffness asymmetry (anisoelasticity) on a stand-alone digital signal processing platform. Using the new method, the precession angle-dependent bias error and minimum rate threshold, two issues identified by Lynch for a MEMS RIG 1 due to anisodamping are overcome. To minimize angle-dependent bias, we augment the electronic feedback force of the amplitude regulator with a non-unity gain output distribution matrix selected to correct for anisodamping. Using this method, we have decreased the angle-dependent bias error by a factor of 12, resulting in a minimum rate threshold of ~3 °/s. To further improve RIG performance, an electronically induced self-precession rate is incorporated and successfully demonstrated to lower the rate threshold.
This paper demonstrates a dual-mode actuation and sensing scheme for differential operation and self-calibration of axisymmetric Coriolis resonant gyroscopes. The proposed scheme actuates both modes ...of an axisymmetric gyroscope with two identical in-phase excitation signals, and senses both modes concurrently. This dual-mode actuation architecture utilizes the difference of the individual mode outputs to cancel out the common-mode bias terms, and provide rate-independent frequency split monitoring. The symmetry of the dual-mode architecture can be utilized to provide in-run scale factor calibration capability by mimicking the mechanical Coriolis force in the electrical domain, thereby providing a virtual electrical rotation to the gyroscope, to estimate the drift of the physical scale factor over time and temperature. The dual-mode architecture is demonstrated on a 2.625-MHz substrate-decoupled bulk acoustic wave gyroscope. The inherent bias cancellation provides sub10°/hr bias instability, with 1.4× improvement of angle random walk, as compared with the conventional single-mode actuation scheme. Benefiting from the in-run mode-matching capability, the dual-mode actuation scheme exhibits 45× reduction of bias drift over a temperature range of 10-80 °C. In-run scale factor calibration achieves 150× reduction of scale factor turn-on repeatability error down to 62 ppm, and over 100× reduction of the temperature drift of scale factor over 10-50 °C.
This letter presents a fused silica inductive vibrating ring gyroscope (IVRG). The resonator of the gyroscope is fabricated on a 4-inch fused silica wafer. Benefiting from the technique of ...laser-induced assisted etching (LIAE), the microstructures on the fused silica wafers have an extremely high aspect ratio of 60.2 and the average roughness of the sidewall is <inline-formula> <tex-math notation="LaTeX">0.41~\mu </tex-math></inline-formula> m. The voltage can be directly extracted from the resonator without performing a C/V converter. This device has a Q factor of 1007196 and 1104764 and a resonant frequency of 17950.77 Hz and 17950.86 Hz after vacuum packaged. Although the gyroscope has a maximum angle-dependent bias drift of <inline-formula> <tex-math notation="LaTeX">0.42~^{\circ } </tex-math></inline-formula>/s when operated in the rate-integration mode, the angle tracking error is only 4.3° (34.1ppm) after 30 seconds high-speed rotation test.
Reducing the dimensions of optical gyroscopes is a crucial task and resonant fiber optic gyroscopes are promising candidates for its solution. The paper presents a prototype of a miniature resonant ...interferometric gyroscope of a strategic accuracy class. Due to the use of passive optical elements in this gyroscope, it has a great potential for miniaturization, alongside a low production cost and ease of implementation, since it does not require many feedback loops. The presented prototype shows results on a zero instability of 20°/h and an angle random walk of 0.16°/√h. A theoretical model explaining the nature of the multipath interference of resonant spectra and establishing the relationship between the resonator parameters and the output parameters of the presented prototype is proposed. The results predicted are in agreement with the experimental data. The prototype gyroscope demonstrates a scale factor instability and a change in the average signal level, which is due to the presence of polarization non-reciprocity, occurring due to the induced birefringence in the single-mode fiber of the contour. This problem requires further investigation to be performed.
Quality factor has played a crucial role in determining the temperature and anti-shock performance of a microelectromechanical system (MEMS) gyroscope. This paper presents an innovative approach to ...enhance the thermal stability of quality factor for a micro resonant sensors based on Joule effect in-situ dynamic tuning for the first time. By unitizing an active control loop that adjusts the dissipation energy of a resistive element connected to the mechanical structure via monitoring the driving voltage, the device damping can be effectively tuned in real-time, thus stabilizing the quality factor. The proposed method is demonstrated on a vacuumed sealed monolithic dual-axis gyroscope. The results show that the relative variation of the Q-factor significantly reduced by more than 3000× down to ∼150ppm from -40℃ to +60℃, which achieves only ∼30ppm of driving voltage stability with ∼3500× reduction. Benefiting from the quality factor precise control capability, the electrical coupling from the drive mode to the sense mode is therefore suppressed, exhibiting more than three-fold times improvement of the zero bias thermal drift over 100℃ range. This technique is also promising for enhancing the anti-shock performance.
In order to improve the temperature drift modeling precision of a tuning fork micro-electromechanical system (MEMS) gyroscope, a novel multiple inputs/single output model based on genetic algorithm ...(GA) and Elman neural network (Elman NN) is proposed. First, the temperature experiment of MEMS gyroscope is carried out and the outputs of MEMS gyroscope and temperature sensors are collected; then the temperature drift model based on temperature, temperature variation rate and the coupling term is proposed, and the Elman NN is employed to guarantee the generalization ability of the model; at last the genetic algorithm is used to tune the parameters of Elman NN in order to improve the modeling precision. The Allan analysis results validate that, compared to traditional single input/single output model, the novel multiple inputs/single output model can guarantee high accurate fitting ability because the proposed model can provide more plentiful controllable information. By the way, the generalization ability of the Elman neural network can be improved significantly due to the parameters are optimized by genetic algorithm.
•The temperature variation experiment based on temperature change rate is carried out.•Temperature drift model based on T, temperature change rate and △T is proposed;•The genetic-Elman NN is proposed to establish the temperature drift model.
With the rapid development of modern physics, atomic gyroscopes have been demonstrated in recent years. There are two types of atomic gyroscope. The Atomic Interferometer Gyroscope (AIG), which ...utilizes the atomic interferometer to sense rotation, is an ultra-high precision gyroscope; and the Atomic Spin Gyroscope (ASG), which utilizes atomic spin to sense rotation, features high precision, compact size and the possibility to make a chip-scale one. Recent developments in the atomic gyroscope field have created new ways to obtain high precision gyroscopes which were previously unavailable with mechanical or optical gyroscopes, but there are still lots of problems that need to be overcome to meet the requirements of inertial navigation systems. This paper reviews the basic principles of AIG and ASG, introduces the recent progress in this area, focusing on discussing their technical difficulties for inertial navigation applications, and suggests methods for developing high performance atomic gyroscopes in the near future.
In the present study, the size- and time-dependent viscoelastic bending analysis of rotating spherical nanostructures made of functionally graded materials (FGMs) is performed. To simulate gyroscopic ...rotation, the structure is assumed to be rotated around two axes with constant angular accelerations. The nonhomogeneous nanostructure with functionally variable thickness (FVT) is assumed as FGM/FVT structure. Geometrically, the inner side of the structure has a spherical shape and the outer side is considered as an ellipse or any other arbitrary function. The size-dependent governing equations and related boundary conditions are obtained by implementing Hamilton's principle based on Eringen's nonlocal elasticity and first-order shear deformation theories. The resulting equations are solved using the Semi-Analytical Polynomial Method (SAPM). The time-dependent deflection is obtained by applying the boundary and initial time conditions. The effects of a hygro-thermal environment and porosity are also considered for a comprehensive analysis. Since no research has been conducted so far on the nonlocal viscoelastic dynamic analysis of FGM/FVT gyroscopes, the classical results are compared with the previously published works and ABAQUS software as well as the effect of many parameters on the results including nonlocality, FGM properties of the structure, thickness changes, angular velocities and accelerations, hygro-thermal environment, porosity, and viscoelastic properties are thoroughly conducted.
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