数字机械抖动控制的一种改进方案及噪声注入方法

Introduction of an improved digital mechanically dithered control and noise injection method

数字机械抖动控制是机抖激光陀螺小型化发展的关键技术,有必要对其进行详细探讨。与模拟机械抖动电路的正弦波驱动方式不同,数字机械抖动电路采用方波驱动方式,具有其特殊性,本文主要关注数字机械抖动控制系统的两大关键问题,抖动效率问题和随机噪声注入问题。首先,在介绍抖动机构传递函数的基础上,分析了数字抖动控制原理,指出由于附加相位导致谐振频率偏离进而影响抖动效率的问题,基于此提出了通过移相来保证高抖动效率的方法;文中还关注数字抖动系统注入随机噪声的方法,经过计算,指出了向数字抖动控制系统注入抖动随机噪声的特殊性,并给出了一种利用软件对随机数进行处理以注入随机噪声的方法。实验结果表明,经过改进的数字机抖控制回路能够保证陀螺抖动在谐振点且抖动效率提高30%,同时采用新方法注入的抖动随机噪声保证陀螺消除动态闭锁误差。

Digital control of mechanical dither is an important technology for minimizing circuit scale of mechanically dithered ring laser gyro.The analog dithered circuit applies sinusoidal wave to drive,while the digital mechanically dithered circuit applies square wave to drive and has some special characters.In this paper,two main problems of the digital dithered control system are concerned,one is dithered efficiency and the other is noise injection method.Firstly,the digital dithered control loop is analyzed based on transfer function of the dithered mechanism.Experiment result shows that the dithered efficiency falls greatly because of the additional phase,and the dithered controller is not actually working on resonance point.Based on this,an improved digital control loop is introduced.Secondly,the method of random noise injection is concerned.The character of noise injection into digital dithered control loop is analyzed,and a random noise injection method is introduced which deal with random number using software.Experiment result shows that the improved digital mechanically dithered loop works on the resonance point of the dithered mechanism and has improved dithered efficiency by 30%.In addition,the new noise injection method can also eliminate the frequency lock-in error.