Guo Rui, Wei Zhennan, Wang Ning, Wu Hongbo, Yi Guoxing
Hemispherical resonator gyro operating in rate-integrating mode can detect angular rates over a wide rotation range. However, due to limitations in manufacturing processes, damping anisotropy errors are usually inevitable. To address the problems of zero-bias error and dynamic performance degradation in the output angular rate of rate-integrating hemispherical resonator gyro caused by damping anisotropy errors, an online self-calibration method of gyro damping anisotropy errors based on initiative precession control of standing wave is proposed. Firstly, starting from the nonideal motion equation of hemispherical resonator gyro, amplitude control quantity, quadrature control quantity for resonator, and circumferential distribution equations of standing wave drift error are derived. Secondly, with the control condition of constant standing wave initiative precession angular rate, a parameter identification algorithm based on the recursive least squares method is established, and the effectiveness of parameter identification is verified through experiments. Finally, an online compensation method for damping error is designed and verified through physical experiments. The experimental results show that the gyro damping parameter identification results can converge within 150 s with the assistance of offline calibration data, the steady-state value can reflect the actual damping distribution characteristics of the gyro within the range of ±5%. After compensation, the peak-to-peak drift error induced by the gyro’s fourth harmonic is reduced by 97.61%, and the damping anisotropy error is significantly suppressed. Under the condition of standing wave initiative precession, the zero-bias instability decreases by 85.68%, and the gyro noise characteristics reflected by the gyro Allan variance curve are significantly improved.
