抑制闭环光纤陀螺高动态角运动测量误差的校正回路设计

Design of correction loop for suppressing high dynamic angular motion measurement error of closed-loop FOG

闭环光纤陀螺控制回路存在固有延迟,若通过约束回路增益来抑制回路超调和振动零偏效应,会在一定程度上限制光纤陀螺带宽。这导致陀螺在高动态条件应用时会产生较大的角速率跟踪误差,进而影响系统的动态性能。为此,提出了一种回路校正技术,以减小大动态角速率跟踪误差及瞬态角误差。对校正后的回路稳定裕度及频率特性进行了分析,对特征角速率跟踪误差及瞬态角误差进行了仿真。仿真结果表明,对于某型光纤陀螺,采用所提出的回路校正技术和设计参数,在100°/s^(2)的角加速度输入条件下,角速率跟踪误差和最大瞬态角误差分别为13.1μrad/s和6.99μrad,比未经校正前降低了一个数量级以上,带宽提高为原来的4倍且依然保证了光纤陀螺的稳定性能,满足特定车载冲击振动条件下的角运动测量精度要求。

The control loop of closed-loop fiber optic gyroscope(FOG)has inherent delay.If the loop gain is constrained to suppress the loop overshoot and vibration bias effect,the bandwidth of FOG will be limited to a certain extent,which leads to a large angular rate tracking error when the gyroscope is applied in high dynamic conditions and affects the dynamic performance of the system.A loop correction technique is proposed to reduce large dynamic angular rate tracking error and transient angular error.The loop stability margin and frequency characteristics after correction are analyzed,and the characteristic angular rate tracking error and transient angular error are simulated.The simulation results show that for a certain type of FOG,by using the proposed loop correction technique and design parameters,the angular rate tracking error and the maximum transient angular error are 13.1μrad/s and 6.99μrad respectively under the condition of angular acceleration input of 100°/s^(2),which are more than one order of magnitude lower than before correction.The bandwidth is increased by 4 times and the correction loop does not affect the stability performance of the closed-loop FOG,which can meet the requirements of angular motion measurement accuracy under the condition of specific vehicle impact vibration.