Error Analysis and Measurement Method Design for the Hemispherical Resonator Gyro
|School||Harbin Institute of Technology|
|Course||Control Theory and Control Engineering|
|Keywords||HRG Allan variance Error analysis Measurement method design|
Hemispherical Resonator Gyro （HRG） is a promising sensitive device used in SINS fixed on aeronautics and aerospace flying vehicle, it has the features of longevity and high-precision which is the trend of gyros development. HRG has a wide application in military arms, aeronautics, and aerospace fields etc, especially in the field of deep space exploring because of it is structural characteristics and outstanding specifications, so it’s the optimum option for gyroscopes which will be used in environment satellites, communications satellites, lunar probe astronomical telescopes and deep space exploring etc.The structure and the advantages over other kind of gyro were presented at first, the practical applications in the space task were introduced, and the research situation and shortcomings of domestic and overseas HRGs were summarized. Then the fundamental theory for the HRG was discussed and analysed, and the loop-shaped model motion equations were deduced using Bubonov-Galerkin method under Kirchhoff-Lyav hypothesis. After that the concept for the quality factor of resonator was derived, the principle of the position excitation and signal acquisition system were deduced, and the main error sources of HRG were given, which laid a foundation for the further work.The characteristics of noise sources in the semiconductor device and the concept for Allan variance were expounded, aiming at the stochastic noise features of HRG, the schemes including sampling the outputs of different HRGs at the same sampling frequency, sampling the outputs of the same HRG at the different sampling frequencies and the 24-position test plan were designed for measuring Allan variance coefficients of domestic HRGs, by which the shortcomings of domestic HRGs were determined, and the contrast of the new HRGs to the old ones is made. It is proved that the new type of HRGs has the higher accuracy than the old ones by analyzing Allan variance coefficients, although the burst noises exist in the new ones and can not be neglected.The working principle of excitation and signal acquisition system, the sensitivity of the mass unbalance of the resonator to the vibration were studied using the second-order vibration model of HRG.The influences of angular alignment errors of the drive electrodes and the exciting-electrodes, the circumferential distribution errors of drive electrodes and the exciting-electrodes, the mass unbalance error of the resonator, on the output of HRG were analyzed by MATLAB simulation, and their concerned formulas are achieved.The methods of identifying gyro errors were studied, the measurement principle for the 1st, 2nd, 3rd harmonic deviations of gyro mass, the drift concerned with the specific force were induced under the current condition of our lab, polar axis tumble test is conducted, the conclusion that the drift errors of HRG concerned specific force can not be neglected is reached.The output of the gyro affected by the radial angular velocity is calibrated, so mass balancing technology and welding technology of domestic HRGs must be improved further.