风载对4m地基望远镜成像质量的影响及其校正

发布时间：2017-12-27 05:27

本文关键词：风载对4m地基望远镜成像质量的影响及其校正　出处：《中国科学院长春光学精密机械与物理研究所》2017年博士论文　论文类型：学位论文

【摘要】：随着地基光电望远镜口径的不断增大,以及开放式圆顶的广泛应用,风载作为外力扰动引起的望远镜系统成像质量下降的问题越来越严重。为了满足地基光电望远镜对空间目标的探测能力,保证光学系统的成像质量,在设计阶段定量地分析风载对成像质量的影响并对其进行有效地校正至关重要。4m地基望远镜系统涉及机械,液压,控制和光学等领域,本文采用集成建模的方法分析了风载对4m地基望远镜成像质量的影响,并提出了相应的校正措施。本文首先对4m地基望远镜外流场的计算流体力学模型进行了瞬态分析,采用Zernike多项式拟合主镜镜面的风压值,对拟合系数进行主成分分析和谐波叠加模拟,生成了主镜镜面的时序风压值。其次,基于失调光学系统线性化理论,推导出了光学系统的灵敏度矩阵。通过光机接口前处理,建立了4m地基望远镜的光机系统模型,并对其进行内平衡模型缩减。然后,采用键合图方法建立了4m主镜液压whiffletree支撑系统的动力学模型,对主镜的位置进行了解算,并建立了主镜液压伺服系统的控制模型。接着,采用Guyan缩减技术求出4m望远镜主镜的响应矩阵,通过奇异值分解得到主动光学系统主镜镜面变形的弯曲模式,以液压支反力作为反馈信号对风载引起的主镜镜面变形进行主动光学校正,校正效率达到了70%以上。最后,在Simulink中分别建立4m地基望远镜的集成模型,然后分析不同风速不同俯仰角下系统的斯特列尔比。分析结果表明80%v风速任意俯仰角的情况下,光学系统的斯特列尔比大于0.8,望远镜系统可以正常工作;95%v风速任意俯仰角情况下系统的斯特列尔比小于0.8,望远镜成像质量受到严重的影响,系统无法正常工作。最后搭建1.2m反射镜液压Whiffletree支撑系统动力学性能测试实验,将实验测得的系统动力学性能指标与集成模型仿真分析得到的性能指标对比,误差在15%以内,验证了主镜液压支撑系统集成模型的准确性。
[Abstract]:With the ever increasing caliber of ground-based electro-optical telescope and the wide application of open dome, the problem of the imaging quality degradation of the telescope system caused by wind load is becoming more and more serious. In order to satisfy the ground-based photoelectric telescope's ability to detect space targets and ensure the imaging quality of optical system, it is very important to quantitatively analyze the influence of wind load on imaging quality and correct it effectively in the design stage. The 4m ground-based telescope system involves mechanical, hydraulic, control and optical fields. In this paper, the influence of wind load on the imaging quality of 4m ground-based telescope is analyzed by using the integrated modeling method, and corresponding correction measures are put forward. In this paper, we first analyzed the computational fluid dynamics model of the external flow field of the 4m foundation telescope. The Zernike polynomial was used to fit the wind pressure value of the main mirror surface. Principal component analysis and harmonic superposition simulation were applied to the fitting coefficient, and the time series wind pressure value of the primary mirror surface was generated. Secondly, based on the linearization theory of the misaligned optical system, the sensitivity matrix of the optical system is derived. The optical machine system model of the 4m foundation telescope is established by the optical machine interface pretreatment, and the internal balance model is reduced. Then, we use bond graph method to establish the dynamic model of the 4m main mirror hydraulic whiffletree supporting system. We calculate the location of the primary mirror and establish the control model of the main mirror hydraulic servo system. Then, using the Guyan reduction technology response matrix 4m telescope primary mirror is calculated, the decomposed bending mode active optical system of primary mirror deformation by singular value, with hydraulic force as the feedback mirror signal of wind load caused by the active optical distortion correction, the correction efficiency reached more than 70%. Finally, the integrated model was established by 4m foundation telescope in Simulink, and then analyzes the different wind speed different pitching angle of system under the Strehl ratio. The results show that the 80%v velocity of arbitrary pitching angle under the condition that the optical system of the Strehl ratio is greater than 0.8, the telescope system can work normally; the wind speed 95%v arbitrary pitching angle system under the conditions of the Strehl ratio is less than 0.8, telescope imaging quality was seriously affected, the system does not work properly. Finally, the 1.2m mirror Whiffletree support hydraulic experimental system dynamic performance test, the index system of dynamic performance testing and integration model simulation comparative analysis of performance indicators, the error is less than 15%, to verify the accuracy of the primary mirror support hydraulic system integration model.
【学位授予单位】：中国科学院长春光学精密机械与物理研究所
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TH751

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