Heimsten Rikard, MacMynowski Douglas G, Andersen Torben, Owner-Petersen Mette
Lund Observatory, Lund University, Sweden.
Appl Opt. 2012 Feb 10;51(5):515-24. doi: 10.1364/AO.51.000515.
While it is attractive to integrate a deformable mirror (DM) for adaptive optics (AO) into the telescope itself rather than using relay optics within an instrument, the resulting large DM can be expensive, particularly for extremely large telescopes. A low-cost approach for building a large DM is to use voice-coil actuators connected to the back of the DM through suction cups. Use of such inexpensive voice-coil actuators leads to a poorly damped system with many structural modes within the desired bandwidth. Control of the mirror dynamics using electro-mechanical sensors is thus required for integration within an AO system. We introduce a distributed control approach, and we show that the "inner" back sensor control loop does not need to function at low frequencies, leading to significant cost reduction for the sensors. Incorporating realistic models of low-cost actuators and sensors together with an atmospheric seeing model, we demonstrate that the low-cost mirror strategy is feasible within a closed-loop AO system.
虽然将用于自适应光学（AO）的变形镜（DM）集成到望远镜本身而不是在仪器中使用中继光学器件很有吸引力，但由此产生的大型DM可能很昂贵，特别是对于极大的望远镜。构建大型DM的一种低成本方法是使用通过吸盘连接到DM背面的音圈致动器。使用这种廉价的音圈致动器会导致系统阻尼不佳，在所需带宽内存在许多结构模式。因此，在AO系统中集成时需要使用机电传感器来控制镜面动力学。我们引入了一种分布式控制方法，并表明“内部”背面传感器控制回路不需要在低频下运行，从而显著降低了传感器成本。将低成本致动器和传感器的实际模型与大气视宁度模型相结合，我们证明了低成本镜面策略在闭环AO系统中是可行的。
