快速反射镜驱动形式对伺服带宽的影响

Influence of driving forms on servo bandwidth in fast steering mirror

为了提高大行程快速反射镜系统的伺服带宽,提出一种直线驱动形式的快速反射镜。该快速反射镜以音圈电机作为驱动器,利用滚珠花键约束驱动器工作方向,将传统的弧线驱动转变为直线驱动。首先,对直线驱动快速反射镜进行了结构设计,重点分析了直线驱动单元的组成形式与特点;接着,从约束条件分析驱动形式对系统伺服带宽的影响因素,并推导两种驱动形式下,快速反射镜在大行程运动时的动力学方程;最后,利用有限元分析得出快速反射镜的机械谐振频率,并通过实验测试对两种驱动形式下快速反射镜的伺服带宽进行了验证。结果表明,在相同的实验条件下,相较于传统弧线驱动形式,直线驱动形式快速反射镜的机械谐振频率由121.8Hz提高至229.9Hz,伺服带宽由40.3Hz提高至75.1Hz,分别提高了88.8%、86.4%,满足快速反射镜在大行程工作状态下的高带宽设计要求。

To improve the servo bandwidth of fast steering mirrors with large stroke,a fast steering mirror with linear driving mode was proposed.Voice coil actuators were used to drive the fast steering mirror,and ball splines were used to constrain the direction of the drive,which transforms the traditional arc drive into a linear drive.First,the structure of a fast steering mirror driven by linearity was designed.Subsequently,the composition and characteristics of linear driving were analyzed.Subsequently,after the influence of the factors of the driving forms on the servo bandwidth was analyzed considering the constraint condition,the dynamic equations of the fast steering mirror with large stroke in the two driving modes were obtained.Finally,the mechanical resonance frequencies of the fast steering mirror were obtained through finite element analysis,and its servo bandwidths were verified through experimental tests. The experimental results indicate that,under the same experimental conditions,compared with the traditional arc drive,the resonant frequency of the fast steering mirror increases from 121.8 Hz to 229.9 Hz,and the servo bandwidth increases from40.3 Hz to 75.1 Hz,indicating an increase of 88.8%and 86.4%,respectively.These results satisfy the design requirement of high servo bandwidth for fast steering mirrors in large stroke state.