| As a kind of high precision,high reliability,long working life and shock resistance solid state wave gyro,hemispherical resonant gyroscope has a broad development prospect,it has been widely used in aerospace,navigation guidance and other fields,and the research on improving the accuracy of hemispherical resonant gyroscope has become a hot research topic in recent years.Therefore,it is important to study the error mechanism and suppression method of hemispherical resonant gyroscope.In this paper,the hemispherical resonant gyroscope has been taken as the research object,and several aspects have been studied from the kinetic equations,error analysis,full-angle mode control loops and error restraint methods,etc.The main research contents of this paper are as follows:(1)Analysis of the working principle of hemispheric gyroscope.The structure of the hemispherical resonant gyroscope is introduced and the operating principle of the hemispherical gyroscope is analysed;the hemispherical thin-shell model is simplified to a two-dimensional vibration model of a two-dimensional spring-damped-mass and the dynamical equations of the gyroscope are derived in detail;the principle of outof-plane capacitance detection and electrostatic excitation of the hemispherical resonant gyroscope is analysed;and the operating mode of the hemispherical gyroscope is introduced.(2)Structural error analysis of hemispherical gyroscopes.The structural errors of hemispherical resonant gyroscopes are investigated;the error model of hemispherical resonant gyroscopes is analysed,the effects of resonator stiffness asymmetry,damping non-uniformity and mass error on resonator vibration orbital parameters are theoretically derived,and the error propagation equations are established based on the averaging method;on the basis of the out-of-plane capacitance model,the out-of-plane capacitance errors caused by the eccentricity of resonator assembly and mounting inclination are analysed.(3)Analysis of whole-angle mode rate threshold effect and research on suppression methods.The rate threshold problem of the gyroscope due to uneven damping is analysed through the derivation of the equation.Aiming at the misalignment of the preset virtual speed caused by the non-repetitive error,the virtual speed caused by the preset virtual Coriolis force is calibrated before entering the working mode.Finally,the virtual rotational speed obtained by subtracting the calibration from the detected output angular velocity is used as the actual detected angular velocity output,thereby suppressing the gyro output zero error caused by the virtual rotational speed drift.(4)Stiffness error analysis and research on suppression methods.The negative effect of stiffness error on gyro accuracy is analyzed,the working principle of adaptive filter is analysed,and the method of stiffness defect parameter identification based on adaptive filtering algorithm is introduced.Based on the electrostatic force equation of out-of-plane capacitance,the principle of electrostatic tuning based on electrostatic negative stiffness effect is analysed,and the stiffness matrix is adjusted by closed-loop tuning method,followed by the simulation verification of the stiffness correction scheme to achieve the suppression of stiffness defect parameters.(5)Error analysis and optimization of control variables in whole-angle mode.The hemispherical resonant gyroscope whole-angle mode control method is analysed;the working principle of the control loop required to maintain the resonant oscillator amplitude,suppress quadrature and track phase is introduced;theoretical derivation and simulation analysis of the control loop error caused by the mismatch between the gyroscope detection and drive signal gain and the control system delay are carried out;an algorithm optimisation method is proposed on the basis of the conventional control algorithm,so as to improve the response accuracy of the control loop and reduce the angle estimation error. |
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