【作者】 宋辞；

【导师】 戴一帆；

【作者基本信息】 国防科学技术大学 ， 机械工程， 2012， 博士

【摘要】 现代科学技术的飞速发展，使得基于离轴非球面光学零件的反射式光学系统在对空观测、对地观测、极紫外光刻等前沿领域得到了广泛应用。相比同轴光学零件而言，离轴非球面光学零件复杂的制造特征使得其制造过程不仅存在面形误差收敛特性、加工精度可达性等问题，而且面临特征量参数控制、面形误差检测以及高精高效工艺路线等难题。因此，离轴非球面光学零件的加工一直是现代光学制造领域的重点和难点问题。目前，现代光学系统对离轴非球面光学零件需求日益增长，传统光学零件加工技术已经无法满足实际应用需求。磁流变抛光技术作为一种新兴的光学加工方法，具有去除函数稳定可调、加工过程确定可控、加工结果精确可预测、边缘效应小、表面质量高、亚表面损伤低以及工艺适应性强等独特优势，在离轴非球面光学零件制造方面具有潜在的应用前景。本论文以离轴非球面光学零件的高精高效制造为需求牵引，针对离轴非球面磁流变抛光过程中的关键理论和工艺问题开展研究，旨在实现面形误差和特征量参数双重约束条件下的离轴非球面光学零件的磁流变抛光，形成基于磁流变抛光技术的加工工艺路线，从而提升我国离轴非球面光学零件的制造水平。论文的研究工作主要包括以下几个部分：1、基于离轴非球面的曲率半径连续变化、非线性、大矢高、大离轴量、大口径等制造特征，衍生出相关理论问题：变曲率去除函数建模、非线性成形过程建模、高动态性驻留时间模型及算法。通过这些理论问题的研究，旨在为离轴非球面光学零件磁流变抛光修形提供理论基础和工艺依据。2、在离轴非球面磁流变抛光修形理论的基础上，考虑磁流变抛光修形的实际应用，对离轴非球面磁流变抛光的修形工艺进行优化。通过优化离轴非球面的加工位姿，从而降低离轴非球面的加工难度，提高加工可达性和加工精度。通过离轴非球面的去除函数进行特性评估，形成离轴非球面磁流变抛光修形的两种优化补偿工艺—去除函数线性补偿修形工艺和去除函数非线性补偿修形工艺。本文的修形工艺研究为离轴非球面磁流变抛光修形提供了实现的技术途径。3、面形精度和特征量参数是离轴非球面的双重约束指标，因此在磁流变抛光修形的基础上，还需要对离轴非球面的特征量参数进行有效控制。通过建立离轴非球面光学零件关键特征量参数(离轴量、顶点曲率半径以及二次曲面常数等)的理论模型，可以实现加工过程中的特征量参数控制，保证特征量参数的指标要求。针对离轴非球面零位补偿测量中的两大关键问题：非线性畸变效应和调整量引入误差，分别提出非线性畸变误差控制模型和特征量参数公差域约束条件下的像差分离模型，能够实现离轴非球面面形误差的准确定位和合理评价。特征量参数的控制研究为离轴非球面的磁流变抛光修形提供了加工前提和约束依据。4、基于离轴非球面光学零件的传统加工工艺路线分析，建立基于磁流变抛光技术的创新工艺路线，并结合本文研究的理论和工艺对离轴非球面光学零件进行加工实验验证，最终加工得到同时满足面形精度和特征量参数公差要求的离轴非球面光学零件，为本文的研究结论提供了有效支撑。更多还原

【Abstract】 With the rapid development of modern science and technology, lots of reflectingoptical systems based on off-axis aspheric optical elements are employed widely inmany leading edge fileds which includes space-based observation, ground-basedobservation, and extreme-ultraviolet lithography (EUVL) etc. Compared to theseon-axis optical elements, not only the convergence of surface form error and thereachability of figuring accuracy, but also the control of characteristic parameters, themetrology of surface form error and the high-precision and high-efficiency processingtechnics are all present in the process due to the complicated manufacturing features ofthe off-axis aspheric optical elements. Therefore, the fabrication of off-axis asphericoptical elements is always the emphasis and difficulty in the field of opticalmanufacturing.Nowadays, the requirement of off-axis aspheric optical elements increases a lot inmodern optical system, so the conventional machining methods can not satisfy therequirements of practical application. As one of these new optical machining methods,Magnetorheological Finishing (MRF) owns many unique advantages includinginvariable and controllable influence function, deterministic and controllable figuringprocess, accurate and forecast machining result, little edge effect, good surface quality,low sub-surface damage, as well as excellent flexibility of technics, which is proposedto be potentially applied in the fabrication of off-axis aspheric optical elements. Thisthesis focuses on the high-precision/high-efficiency fabrication of off-axis asphericoptical elements and the key theory and technology in MRF process, aims at thedouble-control of surface form accuracy and characteristic parameters, as well as theestablishment of technological chain, which should improve the national manufacturingability of the off-axis aspheric optical elements.This thesis’s outline is as follows:1、The complex manufacturing features of the off-axis aspheric optical elementsincluding the variant curvature, nonlinear forming, large sagitta, large off-axis distanceand large aperture etc produce lots of theoretical problems which are referred tocurvature-variant influence function model, nonlinear surfacing process model, and highdynamic dwell time model and algorithm. The study of these theoretical problemsprovides the theoretical basis and technology reference for MRF figuring of off-axisaspheric optical elements.2、Based on the MRF figuring theory and its application, the MRF figuringtechnics of off-axis aspheric optical elements are optimized. By means of optimizing themachining position-attitude model, the machining difficulty can be reduced; moreoverthe machining ability and accuracy should be improved. The influence function characteristic of off-axis aspheric optical elements is estimated in order to establish twocompensating figuring processes which refer to influence function linear-compensatedfiguring technology and influence function nonlinear-compensated figuring technology.The study of figuring technology provides the technical approach for MRF figuring ofoff-axis aspheric optical elements.3、Surface accuracy and characteristic parameters evaluate the quality of off-axisaspherical mirrors from two aspects, so we need to effectively control the characteristicparameters as well as the surface accuracy. Theoretical model describing the keycharacteristic parameters (off-axis distance, conic constant and vertex radius ofcurvature) of off-axis aspheric optical elements are established to achieve themonitorition and qualification of characteristic parameters. The nonlinear distortioneffect and the adjustment-induced aberration are two key problems presenting in thenull test of the off-axis aspheric optical elements. To realize the accuracy positioningand effective evaluation of surface form error, the nonlinear distortion control modeland the aberration-separated model of constrained characteristic parameters’ toleranceare both established. The control of characteristic parameters provides the machiningprecondition and constraint criteria for MRF of off-axis aspheric optical elements.4、Based on the analysis of conventional machining technological chain of theoff-axis aspheric optical elements, the novel technological chain with MRF is proposed.The theory and technology in this thesis are both applied in experimental validation, andthe surface form accuracy and tolerance of characteristic parameters are qualified finally,which provides an effective support for the study achievement of this thesis.更多还原