摘要
在数字闭环光纤陀螺中,电子交叉耦合误差对低角速率下陀螺的测量精度有着很大的影响,限制了光纤陀螺的应用。从电子交叉耦合误差产生的机理出发,以经典四态调制法为例进行分析。结果表明,该误差由于复位操作在不同的调制阶段对陀螺输出产生了不同的影响,并直接导致低角速率下死区效应的产生。为解决该问题,通过模拟相加反馈法和比例四态解调法,减少了陀螺的复位阶段,并抑制了调制序列与解调序列的相关性。实验结果表明该方案在保持陀螺静态性能的同时可有效抑制电子交叉耦合误差。
Objective In digital closed-loop interferometric fiber optic gyroscopes(IFOGs),electrical cross-coupling errors significantly affect measurement accuracy,especially at low angular velocities.This limitation restricts application of IFOGs in high-precision environments.Addressing these errors is crucial for enhancing the gyroscope’s performance and reliability.This study aims to explore the mechanisms of electrical cross-coupling errors and develop effective techniques to suppress these errors,thereby improving the overall accuracy and reliability of IFOGs.Methods We begin with a comprehensive analysis of the generation mechanisms of electrical cross-coupling errors in IFOGs.Classical four-state modulation is used as a case study to examine the influence of these errors during different phases of modulation.The four-state modulation method obtains angular velocity information by demodulating four discrete states.However,the reset operations during various modulation phases affect the output differently,leading to dead zone effects at low angular velocities.We propose two methods to address this issue.1)Analog adding feedback method.This method minimizes reset operations by resetting only the feedback phase during modulation.This reduction in reset operations maintains the modulation consistently in the same phase,thus suppressing the dead zone.Nonetheless,due to the inherent influence of electrical cross-coupling,this method introduces an additional bias that must be accounted for in the overall system accuracy.2)Ratio four-state demodulation method.By adjusting the demodulation ratio of the feedback signal,this method mitigates correlation between modulation and demodulation sequences,enhancing measurement accuracy.This technique,combined with the analog adding feedback method,not only addresses the dead zone issue but also helps in reducing the additional biases introduced by electrical cross-coupling.We conduct detailed experiments in a digital closed-loop IFOG system specifically designed to monitor electrical cross-coupling errors under controlled conditions,analyzing the system’s response to low angular velocities and quantifying the dead zone effects caused by these errors.Results and Discussions The results present a detailed analysis of the influence of electrical cross-coupling errors on IFOG performance.These errors cause significant deviations in the gyroscope’s output,particularly at low angular velocities,leading to the dead zone effect where the output remains zero despite of changes in input angular velocity(Fig.7).The anglar velocity of experimentally tested dead zone is 0.2(°)/h,demonstrating the critical need for effective error suppression methods.The analog adding feedback method significantly reduces the number of reset operations,resulting in a substantial decrease in the dead zone.Experimental data(Fig.8)show that this method reduces the dead zone to below the measurement threshold of 0.022(°)/h,thereby improving the gyroscope’s performance.Nonetheless,due to electrical cross-coupling,this method inevitably introduces an additional bias of approximately-0.06(°)/h,which must be carefully managed to ensure accurate measurements.Further analysis(Fig.9)reveals that the combined method of analog adding feedback and ratio four-state demodulation provides a significant improvement in measurement accuracy.By minimizing the correlation between modulation and demodulation sequences,this approach ensures that the gyroscope can operate accurately even at low angular velocities.Experimental results(Table 2)indicate that this method effectively suppresses electrical cross-coupling errors,resulting in more reliable and precise measurements.Conclusions Our study demonstrates the feasibility and effectiveness of the proposed methods in suppressing electrical cross-coupling errors in digital closed-loop IFOGs.The combination of the analog adding feedback method with the ratio four-state demodulation method shows significant improvements in measurement accuracy,particularly at low angular velocities.These techniques mitigate the dead zone effects and guarantee the overall stability and reliability of the gyroscope’s performance.The findings have significant implications for the design and operation of high-precision IFOGs.By addressing the critical issue of electrical cross-coupling errors,the proposed methods pave the way for developing more accurate and reliable gyroscopes,essential for various high-precision applications.Future research will focus on further refining these techniques.
作者
王月恒
王昌朝
缪立军
周一览
张登伟
黄腾超
Wang Yueheng;Wang Changchao;Miao Lijun;Zhou Yilan;Zhang Dengwei;Huang Tengchao(College of Optical Science and Engineering,Zhejiang University,Hangzhou 310027,Zhejiang,China)
出处
《光学学报》
北大核心
2025年第2期118-125,共8页
Acta Optica Sinica
基金
基础研究项目(JCKY2022110C165)。
关键词
数字闭环光纤陀螺
电子交叉耦合误差
死区抑制
相位调制
digital closed-loop fiber optic gyroscope
electrical cross-coupling error
dead zone suppression
phase modulation
