针对采用方波偏置调制、阶梯波反馈调制方案的全数字闭环光纤陀螺"死区"现象的机理进行了实验和仿真研究。为了考察闭环检测反馈环节对干扰的影响,在开环检测的状态下,叠加了长周期固定台阶高度的数字阶梯波,得到阶梯波总高度和开环输出之间的相关性,建立了含干扰通道的光纤陀螺开环检测模型。根据形成数字阶梯波电压大小的等价性,将上述开环模型转换为闭环模型,对闭环简化模型进行了理论分析和仿真计算,并与闭环"死区"测量曲线进行了对比。实验样机阶梯波电压和开环输出线性相关系数为0.97,根据开环测得的耦合系数仿真出的闭环"死区"范围与实验值相差6.7%。结果表明:干扰随阶梯波电压线性变化是闭环光纤陀螺"死区"产生的机理之一。

The dead-zone attached with all-digital close-loop Fiber Optic Gyro (FOG) which employs square wave bias modulation and step wave feedback modulation was researched. The dependence between the height of step wave and open-loop output of the FOG was obtained with a correlation coefficient equaling 0.97,and an open-loop detection model taking this correlation into account was established. Based on the equivalence of digital step wave height set up by fixed step or feedback step,the above open-loop model was modified to close-loop model. The close-loop model was analyzed by theory and simulation. The simulation dead-zone range was compatible with the experimental one with an error of 6.7%. The results show that the linear correlation between the height of step wave and the output is one of the factors of dead zone.