基于系统模型反馈的开环液晶自适应光学系统优化控制方法研究

Earth-based large aperture optical telescope with adaptive optics system could observe and monitor artificial objects, which is of great significance to guarantee the space security of our country. Traditional adaptive optics system is limited by the actuator number of deformable mirror, so it could hardly satisfy the requirement of high resolution imaging in visible light for next generation extremely large aperture telescopes. Due to the huge number of pixels of liquid crystal wavefront corrector, open loop liquid crystal adaptive optics technology is very potential to meet this requirement, and has already got application in some telescopes, but it still couldn’t perform diffraction limited imaging due to its low system bandwidth. In this project, we will solve the problem that open loop systems couldn’t sense the residual error by introducing system model feedback, so as to realize optimal control of open loop liquid crystal adaptive optics system to reduce residual error, and finally increase system bandwidth and imaging resolution, on the basis of no adding or upgrading hardware. This work will realize the high resolution imaging of high speed and dark space target in visible light on Earth-based large aperture optical telescope, and has significant value in space defense and astronomical research.

带有自适应光学系统的地基大口径光学望远镜可以对人造天体进行观测与监视，对保障我国空间安全具有重要意义.传统的变形镜自适应光学技术受限于驱动单元少，很难满足下一代超大口径望远镜可见光波段高分辨率成像的要求。具有高像素密度的开环液晶自适应光学技术的提出，有望满足这一需求，并且已经开始逐步得到工程化应用，但受限于系统带宽，成像分辨率距离系统衍射极限还有一定的差距。本项目拟在不增加、不升级系统硬件的基础上，通过引入系统模型反馈，解决开环系统不能感知系统校正残差的难题，实现开环液晶自适应光学系统的优化控制，来降低系统校正残差，从而提高系统带宽和成像分辨率。本项目的实施将实现地基大口径望远镜对高速和暗弱空间目标在可见光波段的高分辨率成像，在我国空间防卫以及天文研究等领域具有重要的科学及应用价值。

带有自适应光学系统的地基大口径光学望远镜可以对人造天体进行观测与监视，对保障我国空间安全具有重要意义。传统的变形镜自适应光学技术受限于驱动单元少，很难满足下一代超大口径望远镜可见光波段高分辨率成像的要求。具有高像素密度的开环液晶自适应光学技术的提出，有望满足这一需求，并且已经开始逐步得到工程化应用，但受限于系统带宽，成像分辨率距离系统衍射极限还有一定的差距。本项目提出了液晶自适应光学系统的高精度建模方法，成功获得了精度达到97%的系统模型；基于系统模型提出了开环液晶自适应光学系统的优化控制方法，在不增加或更新硬件的基础上，使得系统的误差抑制带宽提高了49%，成像平均对比度提高了80%；相关研究成果成功应用到了一套2米口径望远镜液晶自适应光学系统中，获得了接近衍射极限的高分辨率成像结果。本项目的实施推动了液晶自适应光学技术在地基大口径望远镜上的应用，也为该技术在自由空间激光通讯、眼底视网膜成像、生物显微成像等其他领域的应用打好了基础。