Performance Of Gyroscope Research Articles

宽谱光源相对强度噪声及对闭环光纤陀螺影响研究

宽谱光源相对强度噪声及对闭环光纤陀螺影响研究

Finite Element Modeling of Optical Path Length Control Device for Laser Gyroscope

Optical path length variations due to temperature, manufacturing misalignments, operation environments can affect the performance of ring laser gyroscope (RLG). This paper presents a structural design of optical path length control device (PLC) using finite element analysis. The static analysis and harmonic response analysis of the PLC is performed to investigate the deformation on different voltage, and model analysis is selected to determine the natural frequency and eigenmodes. To validate the simulation results, an experiment on RLG with mode-scanning is carried out and the maximum errors are within 0.025um. The experiment results are found to be in good agreement with the simulation results. The results indicate that the finite element model can be beneficial to designing and optimizing the structural parameters for the PLC.

Modeling of Thermal-Induced Rate Error for FOG With Temperature Ranging From -40 °C to 60 °C

The performance of fiber optic gyroscope (FOG) exhibits temperature dependence due to nonreciprocity phase shift in the fiber coil induced by environmental temperature variation. Research on temperature characteristic is meaningful for high precision FOG working in harsh environment. In this letter, modeling of thermal-induced rate error for FOG with environmental temperature ranging from -40°C to 60 °C is investigated. Temperature dependence of fiber refractive index, thermal expansion of the fiber, and thermal stress of the fiber coating are all considered in our model. Experiments with different temperature change rates between -40°C and 60 °C are performed to verify the effectiveness of the proposed model. Experimental results show great agreement with theoretical values.

An Adaptive Nonlinear Control for Gyro Stabilized Platform Based on Neural Networks and Disturbance Observer

In order to improve the tracking performance of gyro stabilized platform with disturbances and uncertainties, an adaptive nonlinear control based on neural networks and reduced-order disturbance observer for disturbance compensation is developed. First the reduced-order disturbance observer estimates the disturbance directly. The error of the estimated disturbance caused by parameter variation and measurement noise is then approximated by neural networks. The phase compensation is also introduced to the proposed control law for the desired sinusoidal tracking. The stability of the proposed scheme is analyzed by the Lyapunov criterion. Experimental results show the validity of the proposed control approach.

Low‐Loss Polymer‐Based Ring Resonator for Resonant Integrated Optical Gyroscopes

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.

Modal and whirling analysis of coupled lateral and torsional vibration of herringbone gear

The coupled lateral and torsional motions are significant for the herringbone gear in high-speed applications. The present work attempts to investigate the influences of damping, eccentric mass and time varying mesh stiffness of gear pair on the modal vibration of a herringbone gear pair. Under high-speed condition, the gyroscopic performance as a result of coupled lateral and torsional motions cannot be ignored. To achieve a targeted analysis, the equivalent mesh stiffness of the herringbone gear pair is calculated in preprocessing based on the finite element method by considering the thin rim and web. Subsequently, an analytical model for coupled lateral and torsional motions of the herringbone gear is proposed. Then, the natural frequencies, synchronous whirling speed, critical speed, as well as the transient behaviors with time invariant and time varying stiffness, are calculated numerically. The results in Campbell diagram show that the damping affects the critical speed slightly while the eccentric mass will reduce the critical speed significantly. Transient dynamics analysis shows that no matter which stiffness models are used, the high frequency components are predominant, which may be the results of frequency veering phenomena at high order natural frequency. The present work indicates the necessity of paying attention to the critical speed relative to mesh frequency in high speed gear applications.

Dynamics of an all-optical atomic spin gyroscope

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.

Transmitting spectra-temperature characteristic of single-mode fiber coupler for fiber gyro application

The relationship between the transmitting spectra characteristic of a fused single mode fiber coupler (SMFC) and the performance of interferometric fiber-optic gyroscope (IFOG) is analyzed in theory firstly. Then the transmitting spectra-temperature characteristic of SMFC is experimented, and the influence of the spectrum-stability of the SMFC on IFOG is simulated and experimented. Through the theory analysis and experiment research, it is confirmed that the spectrum output from the SMFC's throughput port is more stable than that output from the coupled port, and the bias instability of the rotation errors induced by the variation of spectrum output from the SMFC's coupled port is 10 times of that output from the throughput port. Therefore, to choose the SMFC's throughput port as the input port for navigation-grade gyroscope is an effective method to improve the IFOG's performance.

Design and performance analysis of a nanogyroscope based on electrostatic actuation and capacitive sensing

In this paper, a vibrating beam gyroscope with high operational frequencies at mode-matched condition is proposed. The model comprises a micro-cantilever with attached tip mass operating in the flextural–flextural mode. The drive mode is actuated via the electrostatic force, and due to the angular rotation of the base about the longitudinal axis. The secondary sub-nanometric vibration is induced in the sense direction which causes a capacitive change in the sense electrodes. The coupled electro-mechanical equation of motion is derived using the extended Hamilton's principle, and it is solved by direct numerical integration method. The gyroscope performance is investigated through the simulation results, where the device dynamic response, rate sensitivity, resolution, bandwidth, dynamic range, g sensitivity and shock resistance are studied. The obtained results show that the proposed device may have better performance compared to commercial micro electromechanical gyroscope characteristics.

Improving mechanical performance of mems gyros

The article focuses on improving the mechanical performance of MEMS gyros exposed to constant accelerations, linear and angular vibrations, and shocks. New designs of MEMS gyros are covered, and development trends are analyzed. The use of elastic systems with several inertial bodies, being an important trend in MEMS gyro technology, is discussed.

Liquid-Suspended Rotor Gyroscope Multiphase Driving Technology

Liquid-suspended rotor micro-mechanical gyroscope uses a high-speed rotating hollow rotor in response to the density of the liquid as the mass to do the angular velocity detection. In order to improve the liquid-suspended gyroscope's performance, this paper suggested a new high performance magnetic driving technology. In this technology, the driving performance is optimized by applying six-phase overlapped driving signal to the twelve driving coils of the stator. With this driving technology, the rotating speed of rotor in 3# industrial white oil can go up to 8700rpm.

Experimental Observation of Low Noise and Low Drift in a Laser-Driven Fiber Optic Gyroscope

We demonstrate that by driving a fiber optic gyroscope (FOG) with a laser of relatively broad linewidth ( ~ 10 MHz), both the noise and the bias drift are reduced to very low levels (0.058°/√h and 1.1°/h, respectively), comparable to the performance of the same gyroscope conventionally driven with a broadband light source. When the laser linewidth is reduced to a low enough value ( ~ 2.2 kHz), the FOG exhibits a higher drift but an even lower noise, about 4 dB lower than with a broadband source, and only 3.5 dB above shot noise. The measured dependencies of the noise and drift on laser linewidth are in good quantitative agreement with the predictions of an advanced model of backscattering errors in a FOG interrogated with coherent light, which confirms that the noise and drift are predominantly limited by backscattering. The use of a laser comes with the additional benefit of a much greater wavelength stability compared to a broadband source, which is expected to translate directly into a much more stable scale factor than possible in conventional FOGs. Residual sources of drift and the prospects for reducing them in order to achieve inertial navigation performance are discussed.

Capillary Condensation Adhesion Phenomena and Analysis of the Micromechanical Gyroscope

In MEMS, the size of micro-structure is usually in the micron and even nanoscale. It's easier to form capillary phenomenon than the macroscopic system. In view of this phenomenon, this article is based on the micro-mechanical gyroscope as the research object, to analyze the occurrence of capillary condensation of adhesion phenomenon. Firstly, we derive the Kelvin equation for capillary condensation, and then combination of the Kelvin equation introduce the capillary condensation of the adhesion phenomenon; Secondly, it analyzes the dynamics characteristics of its structure existing the liquid bridge, and analyzes the causes of the liquid bridge; Finally, it analyzes the capillary adhesion phenomena on the performance of the micro-mechanical gyroscope,as well as how to avoid the generation of capillary condensation adhesion.

Slow-fast light and optical gain effects on sensitivity of integrated optical gyroscope

Since the growing trend requires gyroscopes with compact size, low cost and high integration, the integrated optical waveguide gyroscope was suggested. However, the research in this field is still at a preliminary stage which only focuses on the studies of the material research of core device (i.e. coupled resonator) and the optimization of structural design, limited to the current technology level. In this paper, the development and related theory of slow-light gyro, the impact of optical gain on the waveguide gyro performance are both reviewed, as well as the progress of fast-light laser gyro research. Compared to traditional fiber-optic gyro, the sensitivity of passive slow-light gyro cannot be substantially improved because of the existence of the waveguide transmission loss. Two options are presented to improve the sensitivity, including the schemes of slow-light gyro with active gain and fast-light laser gyro. The development process of the two schemes which has been thoroughly discussed in this paper indicates that no direct experimental or test results have been reported by now, and further studies on theoretical analysis and calculation still need to be done. In the end, a new type of integrated fast-light enhanced laser gyro structure is proposed, which may have great potential applications in low-cost civilian areas.

Research on the Method of Laser Trimming to Reduce the Mode Coupling Error of Micro-Machined Vibratory Gyroscopes

Large mode coupling error would seriously restrict the improvement of gyroscope performance. In order to decrease the adverse influence from mode coupling error, this paper studied the formation mechanism of mode coupling error for a micro-machined vibratory gyroscope and certified the result studied by ANSYS analysis. Based on our analysis, it is found that removing material from both sides of the center lines of oscillation could arouse errors of anti-phase each other, which demonstrates that trimming could reduce mode coupling error on the other hand. Finally, experimental study was implemented on the micro-machined vibratory gyroscope by UV laser micromachining technology. Results indicated that laser trimming method on the basis of the phase relationship between mode coupling error signal and driving signal could effectively degrade the error. For certain prototype, the peak-peak voltage of the mode coupling error could be reduced from 6.6V to 0.2V after trimming when there is no angular velocity input.

Analysis and Optimization of Dynamic Measurement Precision of Fiber Optic Gyroscope

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.

Drift Error Analysis of Atomic Spin Gyroscope

With the rapid development of quantum manipulation technique, atomic spin gyroscope has been demonstrated in recent years. Understanding the sources and the influence of error on the performance of atomic spin gyroscope is important during the design of such devices. The basic principle of atomic spin gyroscope was reviewed and the analysis of error sources presented began with the coupled Bloch equations describing the dynamics of atomic spin gyroscope including magnetic field, light shift and pump-probe non-orthogonality. It was shown analytically that the first order effects of the transverse magnetic fields and imperfections can be eliminated by turning the longitudinal magnetic field on the magnetic field compensation point. The effects of longitudinal magnetic field and light shift imperfections with other terms zeroed contributed only to scale factor of the atomic spin gyroscope. Furthermore, the effects magneto-optical crystal and magnetic shielding due to temperature drift were described and according approaches to suppress these errors were also proposed.

Influence of Sensitive Cavity Structure on the Resolution of Fluidic Gyroscope

The flow distribution of fluidic gyroscope with three different cavities was researched when angular velocity ωi is input. Using Finite element method we calculated two-dimensional flow distribution of fluidic gyroscope with rectangular cavity and two streamlined cavity structures when ωi input. The results show that: with ωi increasing, the fluidic beam centers in three cavities have a more deviation on one side, while in two streamlined cavities it deviates obviously. When ωi is 10rad/s, velocity difference of two thermal wires in streamlined cavity 1 and cavity 2 increase 42.59% and 59.30% respectively compared with rectangular cavity, velocity and y-axial velocity of two thermal wires in streamlined cavity 1 are smaller than rectangular cavity but larger than streamlined cavity 2, but x-axial velocity of two thermal wires in streamlined cavity 1 are smaller than other two cavities, and so is ωi = 15rad/s. It also shows that velocity difference between two thermal wires in streamlined cavity 1 is larger than others, and temperature difference is larger, which can improve the resolution of fluidic gyroscope. This article has laid a theoretical foundation to further enhance performance of fluidic gyroscopes.

Er-doped fiber ring laser gyroscope with reciprocal polarization maintaining cavity

To suppress spatial hole burning, a direction related polarizer is adopted in Er-doped fiber ring laser gyroscope. To decrease the frequency drift caused by fluctuation of environment temperature, the polarization maintaining (PM) fiber is substituted for single mode fiber in the ring cavity. To obtain better reciprocity, two 90-deg rotations of PM fiber are introduced. Through the manners, the stable single-mode continuous wave lasers are observed simultaneously in both output directions. At last, better performance of the ring laser gyroscope based on Er-doped fiber is achieved.

Research on Optimal Weight Choice of Multi-MEMS Gyroscope Data Fusion

The performance of MEMS gyroscope is crucial to its application, and the zero-bias stability is the main characteristic parameter of gyroscope performance. When fusing several outputs of similar MEMS gyroscope, we often use the weighted mean method. The weight has great influence on the fusing result. In this paper, the optimal weight choice used in the fusion of Multi-MEMS gyroscope data is derived based on multivariate numerical theory. Experimental results show that after simulating multi-MEMS gyroscope data fusion on the measurement result of several gyroscopes, the zero-bias stability will effectively improve.