Dynamically Tuned Gyroscope Research Articles

INDIRECT CONTROL GYROCOMPASS FOR LAND MOBILE VEHICLES

This work consists of two parts. The first part is a historical overview of the creation of two generations of marine and land gyrocompasses with direct and indirect control. During the review of pendulum or direct control gyrocompasses, using primary sources and authoritative secondary sources, the main practical and analytical developments that led to the creation of the first industrially applicable marine gyrocompass are highlighted. The review of non pendulum or indirect control gyrocompasses is largely an original study of the origins of their creation that is provided through an analysis of available patents taking into account the lack of other available early sources. There are distinguished the developments according to the patent of Narciss Ach (1906, Germany) where the scheme of the gyrocompass with indirect control probably appeared for the first time, the developments according to the patent of Preston R. Basset (1923, USA), where the scheme of proper tuning of indirect control gyrocompass appeared for the first time, and other developments as well. There are also considered the developments of a gyrocompass with electromagnetic correction by Pavel Koptyaev (1932, 1951-1954, USSR) and the main industrial developments of corrected gyrocompasses in the territory of the former USSR. The review also briefly indicates the main operational properties of marine and land gyrocompasses, including a new generation of gyrocompasses based on fiber-optic gyroscopes (FOG) and hemispherical resonator gyroscopes (HRG), attitude heading reference system (AHRS). The second part of this work reasonably follows from the first part, in which the gyrocompass with indirect control for land mobile vehicles based on a dynamically tuned gyroscope (DTG) on a platform stabilized in the horizon plane is studied. A general model of errors of such gyrocompass is determined, when the main axis of the gyroscope is brought into the plane of the true (geographical) meridian in the direction to the North and in the direction to the South. A hardware compensation scheme for the systematic errors of the gyrocompass is provided. A problem of determining and compensating for the gyroscope own drift relative to the horizontal axis of the suspension is solved through indirect measurements. The estimation of parameters of the indirect control gyrocompass is provided as a device of a navigation accuracy class

动力调谐陀螺仪子空间辨识

To deal with the problems of complex structure parameters,unknown interference factors and lower modeling precision in the Dynamically Tuned Gyroscope(DTG)mechanism modeling by the traditional Subspace Identification Method(SIM),an improved SIM was proposed.Firstly,the DTG state space model sets were determined and DTG inherent colored noises were discussed.Then,the traditional SIM were modified for the colored noise problem and the orthogonal projection of a data Hankel matrix was used to eliminate the SIM bias of traditional method.Finally,a confidence ellipse was introduced in the numerical simulation to analyze the statistics feature of the modified algorithm.Simulation results indicate that the identified results of modified algorithm are unbiased at different colored noise influences,and the variance is related to the noise strength and data length.The identification experiments show that the identification performance of modified SIM is apparently better than that of the traditional SIM,and the identification fitting degree is more than 90%,which means that the modified algorithm is suitable for the DTG system modeling.

A novel calibration procedure for dynamically tuned gyroscope designed by D-optimal approach

Effective calibration and compensation of the deterministic errors of Dynamically Tuned Gyroscope (DTG) are crucial in improving the application precision and performance of DTG. However, conventional calibration procedures used empirical parameter-setting and provided no evidence on optimization in terms of accuracy and calibration time. In this paper, D-optimal experimental designs were constructed to propose a practical 12-position calibration procedure of DTG which can be implemented by the medium-precision turntable. The proposed procedure was tested by a tactical-grade DTG. Test results show that, the fit uncertainty is reduced about 62% for the ox axis and 39% for the oy axis respectively. Furthermore, the new calibration procedure achieves D-optimal accuracy with half of the calibration time of the widely adopted 24-position calibration procedure.

A New Hybrid Gyroscope with Electrostatic Negative Stiffness Tuning

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.

Optimized Design of PM Torquer for Dynamically Tuned Gyroscope

The torquer is an important part of the dynamically tuned gyroscope (DTG). Usually, it can be used as a sensor of angular velocity and acceleration. There are different types of torquer, but the permanent magnet (PM) torquer type is more reliable than the other types. This type of torquer offers significant advantages over other torquers particularly for DTG, such as high reliability, high accuracy, fast response, less volume and weight, etc. As a torquer consists of different parts with different geometry and materials, optimal design could make more convenient solution for different cases. In this paper, a PM torquer is designed in order to achieve maximum torque per ampere; for this purpose, the first governing equations of the torquer will be written, and for the desired object, functions will be arranged. By this procedure, a PM torquer will be designed, and torque performance will be evaluated by 3-D finite-element method. Comparison between the performances of the optimized motor and the initial case shows the prominence of the optimized motor and result improvement.

Modal Analysis of Dynamically Tuned Gyroscope Based on ANSYS11.0

This paper proposed a method to analyses and obtain the vibration identities of DTG(Dynamically Tuned Gyroscope) within the vibration-overloading environment based on ANSYS11.0. Finite element model of DTG was constructed by ANSYS11.0. The Natural Frequencies and vibration modals of DTG in the cases of both being stationary and rotating were studied respectively through the method of modal analysis. The influence of each-rank vibration model of DTG on its output was investigated. The result of this paper provides a stable basis for improving the design of DTG and enhancing the functions of it.

A novel hybrid EMD-based drift denoising method for a dynamically tuned gyroscope (DTG)

Empirical mode decomposition (EMD), a new self-adaptive signal processing method, has been recently developed for nonlinear and non-stationary time series analysis. In this paper, EMD method is described and employed for signal denoising. Aiming at the problems of intrinsic mode function (IMF) criterion in the EMD method, neural network (NN) prediction model and wavelet packet transform (WPT) technology are simultaneously introduced into the EMD method to improve the border effect and to enhance the ability of signal denoising, and thus a type of hybrid EMD-based model is proposed and applied in drift denoising for a dynamically tuned gyroscope (DTG). Experimental results on real drift data from the long-term measurement system of a certain DTG indicate that the proposed hybrid model is feasible and more effective in drift denoising compared with the wavelet and single EMD denoising methods.

EMD- and SVM-based temperature drift modeling and compensation for a dynamically tuned gyroscope (DTG)

In this paper, support vector machine (SVM) is described and applied in the temperature drift modeling and compensation to reduce the influence of temperature variation on the output of dynamically tuned gyroscope (DTG) and to enhance its precision. To improve the modeling capability, empirical mode decomposition (EMD) is introduced into the SVM model to eliminate any impactive noises. The real temperature drift data set from the long-term measurement system of a certain DTG is employed to validate the effectiveness of the proposed combination model. The modeling and compensation results indicate that the proposed EMD-SVM model outperforms the neural network (NN) and single SVM models, and is feasible and effective in temperature drift modeling and compensation of the DTG.

Temperature drift modelling and compensation for a dynamically tuned gyroscope by combining WT and SVM method

Temperature drift is the main source of errors affecting the precision and performance of a dynamically tuned gyroscope (DTG). In this paper, the support vector machine (SVM), a novel learning machine based on statistical learning theory (SLT), is described and applied in the temperature drift modelling and compensation to reduce the influence of temperature variation on the output of the DTG and to enhance its precision. To improve the modelling and compensation capability, wavelet transform (WT) is introduced into the SVM model to eliminate any impactive noises. The real temperature drift data set from the long-term measurement system of a certain DTG is employed to validate the effectiveness of the proposed combination strategy. Moreover, the traditional neural network (NN) approach is also investigated as a comparison with the SVM based method. The modelling and compensation results indicate that the proposed WT-SVM model outperforms the NN and single SVM models, and is feasible and effective in temperature drift modelling and compensation of the DTG.

Stability Analysis of a Dynamically Tuned Gyroscope

Using energy and state space methods, the characteristic equation for a dynamically tuned gyroscope (DTG) is determined and subsequently used in a stability analysis of the system. The stability analysis assumes an ideal system and operation of the DTG within small angles of the nominal position. Finally, stable and unstable configurations of the DTG are demonstrated. The analysis shows that for practical configurations of a DTG, the device is inherently stable.

An AGO–SVM drift modelling method for a dynamically tuned gyroscope

In this paper, the support vector machine (SVM), a novel learning machine based on statistical learning theory (SLT), is described and applied in the drift modelling of the dynamically tuned gyroscope (DTG). As a data preprocessing method, accumulated generating operation (AGO) is applied to the SVM for further improving the modelling precision and the learning performance of the drift model. The grey modelling method and RBF neural network are also investigated as a comparison to the SVM and AGO–SVM modelling methods. The modelling results of the real drift data from the long-term measurement system of a DTG indicate that the SVM method is available practically in the modelling of DTG drift and the proposed strategy of combining SVM with AGO is effective in improving the modelling precision and the learning performance.

A novel hybrid grey-based strategy for improving the model precision of adynamically tuned gyroscope

This paper addresses several grey-based models for reducing the modelling errorof a dynamically tuned gyroscope (DTG). Wavelet transform (WT) and linearregression techniques are introduced into the grey model to enhance the modellingcapability of the GM (1, 1), which is a single variable first-order grey model. Theraw DTG drift data are preprocessed by the WT to eliminate any disturbingimpactive noise. The post-processing data are then used to construct thegrey model. Due to the inherent errors between the modelling outputvalues and actual data, the grey model is further compensated by thelinear regression method. Long-term numerical results that measuredx-axis andy-axisdrift data of a DTG verify the effectiveness of the proposed hybrid strategies. Theneural-network modelling method is also investigated to provide a comparisonwith the grey-based models. It is shown that the hybrid grey model gives a verysatisfactory performance when both the WT and the linear regression methodsare employed.

Digital rebalance loop design for a dynamically tuned gyroscope using H2 methodology

Abstract Presented in this paper is a wide-bandwidth digital torquing rebalance loop for a dynamically tuned gyroscope (DTG) based on H 2 methodology. The role and the importance of a rebalance loop are explained first. The augmented plant model including gyroscope and integrator is composed. Next, an H 2 -based controller is designed for the augmented plant model. Frequency analyses show that the proposed controller maintains a linear relationship between applied input rate and the output of the controller over a wide operating range and keeps the tilt angle small thereby reducing dynamic errors. To verify the performance of the controller in a real environment, a digital rebalance loop for a DTG is designed, fabricated, and examined. From simulation and experimental results, it is confirmed that the controller is robustly stable and has a wide bandwidth, significantly improving the performance of a DTG.