自适应光学系统光轴抖动抑制控制器设计

由于光学平台的结构性谐振以及风吹抖动等因素造成的光轴抖动在很大程度上会降低自适应光学系统的性能,若采用常规积分控制器对这种高频窄带的扰动信号进行抑制,收效甚微,而且有可能将其放大,使得系统无法正常工作。以实际系统观测数据为基础,分析了该扰动的频域特性。针对该扰动的峰值频率以及带宽,借助Smith预测器,提出了一种稳定高效且易于实施的控制器设计方法,讨论了控制器参数与其滤波特性之间的关系,分析了这种控制器对控制对象参数变化的鲁棒性。结果表明,采用新型控制器可以将由光轴抖动引起的单轴倾斜像差的方差降低约60%,弥补了常规控制器的不足。

Design of optical axis jitter rejection controller for adaptive optics systems

Optical axis jitters, which arise from different factors such as wind shaking and structural oscillations of optical platforms, have a significant deleterious impact on the performance of adaptive optics systems. When conventional integrators are utilized to reject such high frequency and narrow band disturbance, the benefits are quite small; even worse, the system may fail to operate normally due to the amplification of jitters. On the basis of observed data, its frequency characteristics were analyzed. With the help of the Smith predictor, one effective and stable technique to design a controller was proposed on account of the peak frequency and bandwidth of the jitter. The relationship between controller parameters and filtering features were discussed, and the robustness of the controller against changing parameters of the control object was investigated. Results show that the variance of one axis aberrations caused by optical axis jitters can be reduced by about 60% as a result of exploiting novel controllers, which compensates the deficiency of conventional controllers.