| As a new instrument for angular velocity measurement in inertial navigation,fiber optic gyroscopes are widely used in military fields such as aviation,aerospace,navigation,and tactical weapons.Aircraft,ships,artillery,tanks and other weapons and equipment are prone to large shocks during operation.Because the fiber optic gyroscope is directly connected to the carrier in the strapdown inertial navigation system,the impact of the impact will be directly transmitted to the fiber optic gyroscope,causing measurement errors.Therefore,this article focuses on the research on the impact characteristics of fiber optic gyroscopes,and aims to reduce the impact errors and improve the measurement accuracy of fiber optic gyroscopes by studying the causes and compensation methods of fiber optic gyroscope shock errors.The fiber optic gyroscope adopts a digital closed-loop feedback control structure.This structure improves the anti-interference ability of the fiber optic gyroscope,but also introduces time lag.Therefore,when the fiber optic gyroscope is subjected to external shocks,the closed loop of the fiber optic gyroscope will cause time delay and cause measurement errors.This paper starts with the causes of measurement error of fiber optic gyroscope under impact conditions.Firstly,the influence of impact on fiber optic loop is studied.The impact error model of fiber optic loop,the generation mechanism of stress-induced additional phase shift and the methods to reduce the impact error of fiber optic loop are studied;then focused on the impact of the impact on the gyro circuit,established the closed-loop control system error model,theoretically derives and simulates the response of the system under different parameters and different inputs,and analyzes the impact of the closed-loop system parameters on the system bandwidth.Since changing the system forward channel gain and sampling frequency can reduce the impact of the impact on the closed-loop system,improving the impact characteristics of the gyro closed-loop system can be improved in three aspects:reducing the steady-state error,increasing the bandwidth and extending the range.Three improvement schemes:fast compensation,frequency doubling modulation and range extension.The relationship between the system forward channel gain in the fast compensation scheme and the phase shift of the system feedback compensation is studied;the relationship between the system detection bandwidth and the optical path bandwidth and the influence of the system sampling frequency on the angular velocity modulation and demodulation in the frequency doubling modulation scheme are studied;the range is studied The influence of the system feedback loop gain on the system range in the expansion scheme.Finally,the impact method of the fiber optic gyroscope in the experiment,the method of analyzing the impact characteristic of the fiber optic gyroscope,the model of the fiber optic gyroscope and the simple calibration method are studied.The three proposed schemes are verified by experiments,and the angular acceleration and impact error of the fiber optic gyroscope when the impact is compensated are analyzed.The fast compensation experiment shows that adjusting the system forward channel gain can ensure that the system can compensate for the nonreciprocal phase shift caused by the impact stably,accurately and quickly;the multiplication modulation experiment results show that this scheme reduces the system sampling time and improves the system detection The bandwidth is better than the fundamental frequency modulation scheme in terms of compensation speed and impact error;the experimental results of range expansion show that when the system is sensitive to external impact,the system can automatically perform range expansion to prevent cross-fringe interference in the system.The experimental research concludes that the improved scheme of the fiber optic gyroscope circuit proposed in this subject has theoretical reference and practical application value. |
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