Precision Enhancement by Compensation of Hemispherical Resonator Gyroscope Dynamic Output Errors.

In order to compensate for the hemispherical resonator gyroscope (HRG) dynamic output drift errors, a novel compensation method is presented. Through deriving the resonator motion equations and analyzing the mechanism of HRG dynamic output drift errors, it is found that the resonator defect nonuniformity is the main cause of the HRG dynamic output errors. By analyzing the mechanisms of these errors, the influence of these error sources is interacted and coupled, and it is difficult to analyze the HRG output error mechanism and establish an error model comprehensively. We proposed a compensation prediction model for the HRG dynamic output to suppress the influence of these errors comprehensively. To establish the high-precision HRG dynamic output compensation model, we proposed an improved variational mode decomposition (VMD) method to achieve an accurate HRG output. First, we used VMD to decompose the HRG output, and the optimal VMD decomposition parameters are achieved by a genetic algorithm. In order to better achieve the effective information, the decomposed components of HRG drift are classified using the sample entropy. Then, the mixed components are further processed using time–frequency peak filtering. Finally, the accurate HRG output is achieved by reconstructing all the effective components. The accurate HRG output is used to construct the training set, and the high-precision HRG dynamic output prediction model is established by long short-term memory (LSTM). The software compensation of the HRG dynamic output drift is realized by the prediction model. The experiment shows that the HRG dynamic output drift is mainly produced by the resonator nonuniformity, and it is strongly correlated with the standing wave azimuth, which verifies the correctness of the mechanism analysis. The HRG dynamic drift peak-to-peak value decreases to $5.715\times 10^{-3 \circ }$ /s, which verifies the effectiveness of the compensation method.