高精度离轴非球面CCOS加工关键技术研究
文献类型：学位论文
| 作者 | 赵璇 |
| 学位类别 | 硕士 |
| 答辩日期 | 2016 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 魏朝阳 |
| 关键词 | 离轴非球面 CCOS 高动态性 加工位姿 组合加工方法 |
| 其他题名 | Study on the CCOS Techniques of Manufacturing High-Precision Off-Axis Aspheric Surfaces |
| 中文摘要 | 离轴非球面元件是一种偏轴非旋转对称的光学元件，在光学系统中采用离轴非球面光学元件可以有效地矫正多种像差，提高成像质量，同时简化系统的结构，减轻系统重量，扩大视场角度且无中心遮拦，因此离轴非球面反射镜及透射镜元件被广泛应用于大型天文望远镜、空间相机及点火装置等光学系统中。现代高精度离轴非球面的制造主要是通过计算机表面成形技术(CCOS)为代表的确定性抛光技术，数控小磨头技术是发展比较早的一种光学加工技术，也是离轴非球面研磨及抛光阶段的主要方法，目前技术上仍存在一些问题需要解决，比如小磨头与非球面表面吻合、高动态性能的要求、加工位姿等。本文以高精度离轴非球制造需求为引导，针对数控小磨头抛光过程中的关键理论和工艺展开研究，以实现高精度离轴非球面的数控加工。论文的主要内容包括： 1.针对离轴非球面高动态工艺性能的要求，对基于线性方程组模型的驻留时间求解算法引入Laplace算子，建立高动态主流时间求解算法，对比低动态驻留时间求解算法，通过matlab仿真，分析其残余误差、驻留速度及驻留速度梯度分布，结果表明高动态驻留时间算法加工精度略小于低动态驻留时间算法，驻留速度梯度分布平缓，能够满足离轴非球面高动态工艺性能要求。在驻留时间的实现上考虑机床动态性能，建立速度约束，缩小实际驻留时间与理论值之间的误差，提高加工精度和效率。 2.针对离轴非球面实际加工位姿摆放问题，通过坐标转换建立子镜坐标系加工模型，对比母镜坐标系加工，仿真结果表明降低了离轴非球面的加工难度，提高加工精度，并通过圆形离轴抛物镜的加工实验验证了子镜坐标系加工模型的有效性。 3.基于CCOS的整体加工思想，设计并完成了离轴非球面数控加工工艺控制软件，实现了工件参数设定、面形及去除函数数据处理、驻留时间计算、抛光路径生成及加工文件输出功能，利用输出的数控代码可以进行实际加工。 4．提出一种CCOS技术与磁流变技术组合加工的加工工艺方法，采用子镜坐标系加工位姿对离轴抛物镜进行铣磨加工，将柔性盘应用于CCOS的抛光修形中，并进行特征参数的测量与控制，最终实现了高精度离轴非球面的制造，加工后的200mm离轴非球面面形精度pv=0.249λ，rms=0.016λ。 |
| 英文摘要 | Off-axis aspheric optical elements are being more and more widely used in large astronomical telescope, space camera and ignition facility modern optical systems, due to the ability of correcting aberrations, improving the image quality, enlarging the field of view without the central obscuration, while simplifying the system structure and reducing the system weight. The modern manufacture of high-precision off-axis aspheric optical elements is mainly through the deterministic polishing technology for which computer controlled optical surfacing (CCOS) technology is as the representative. CCOS technology is proposed early and still the main method for grinding and polishing process of optical elements. However, there are also some problems need to be solved in CCOS to get an off-axis aspheric surface, such as tool fit with the surface, requirements of high dynamic performance and processing position-attitude. This thesis focuses on the high-precision fabrication of off-axis aspheric optical elements and key theory and technology in CCOS polishing process, aims at achieving high-precision off-axis aspheric surface. The thesis’s outline is as follows: 1.Based on the linear equations model dwell time algorithm, by introducing Laplace operator, establish high dynamic dwell time model and algorithm. Compared with low dynamic dwell time model and algorithm, analyzing residual surface error, dwell velocity, and dwell velocity gradient distribution, the results show that machining accuracy of high dynamic dwell time model and algorithm is slightly smaller than that of low dynamic one, dwell velocity gradient distribution is gentle which can meet the requirements of off-axis aspheric high dynamic process performance. Considering the machine dynamic performance in the realization of dwell time, establish velocity constraints to reduce errors between the actual and theoretical value of dwell time which can improve the processing precision and efficiency. 2.For the off-axis aspheric processing position-attitude problem, sub mirror position-attitude model is established through coordinate conversion. Compared with mirror position-attitude model, the simulation results show that sub mirror position-attitude model reduces off-axis aspheric processing difficulty and improve machining accuracy. It is also verified effectively through the circular off-axis parabolic mirror process experiment. 3.The off-axis aspheric process control software is designed based on the mechanism of the removal of CCOS. It realizes the functions of workpiece parameters setting, surface and removal data processing, dwell time calculation, polishing path generation and processing document output(nc code) to make actual polishing. 4.A processing method combined of CCOS and MRF is proposed. In the experiment , sub mirror position-attitude is used successfully and a flexible tool is applied to the CCOS modification polishing . Also the characteristic parameters are measured and controlled effectively. Finally a 200mm high precision off-axis aspheric surface is obtained which the final surface errors is pv=0.249λ,rms=0.016λ. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16959]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 赵璇. 高精度离轴非球面CCOS加工关键技术研究[D]. 中国科学院上海光学精密机械研究所. 2016. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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