柔性铰链结构特性对快速反射镜性能影响分析

Impact analysis of flexure hinge structural characteristics on performance of fast steering mirror

  • 摘要: 柔性铰链作为快速反射镜(fast steering mirror,FSM)的关键部件之一,分析其结构特性对FSM性能的影响,用于指导FSM结构设计。通过将柔性铰链简化为弹性环节,等效为3轴的平动刚度和3轴的转动刚度,基于欧拉动力学,建立了两轴FSM的运动微分方程,搭建了FSM控制系统的Simulink仿真模型;在给定振动环境下,仿真分析了结构谐振频率对FSM性能的影响,指出平动固有频率越大,FSM锁零精度越高,平动固有频率选择在伺服系统增益交界频率2倍以上;考虑到锁零精度要求和电机力矩限制,转动固有频率选择在25 Hz~50 Hz。最后结合实物进行了振动试验,仿真结果与振动试验结果一致,验证了仿真模型的正确性。

     

    Abstract: The flexure hinge is one of the important components of fast steering mirror (FSM). The impact of its structural characteristic on FSM performance was analyzed to guide the structure design of FSM. The flexure hinge was simplified as an elastic joint, which could be equivalent to triaxial translational stiffness and triaxial rotational stiffness. Based on the Euler dynamics theory, the motion differential equation of a two-axis FSM was derived, and the Simulink model of the FSM control system was established. Under the given vibration condition, the influence of structural resonant frequency on FSM performance was simulated. The results showed that the higher the translational resonant frequency, the higher the FSM lock zero accuracy, and the translational resonant frequency should be more than two times of the gain crossover frequency. Considering the requirements of lock zero accuracy and limitation of the motor torque, the rotational resonant frequency should be from 25 Hz to 50 Hz. Finally, the vibration experiment was carried out. The simulation results are accord with the experimental results, which verifies the correctness of the simulation model.

     

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