【作者】 杨智；

【导师】 戴一帆；

【作者基本信息】 国防科学技术大学 ， 机械工程， 2008， 博士

【摘要】 相对于传统光学手工加工,确定性光学加工大幅提高了光学加工的精度和效率。但在确定性加工中,被加工表面除了低频的面形误差外,往往还包含较多的中高频成分。这些空间频带误差的存在严重影响了系统的光学性能,且难以得到控制。其中的关键在于:①目前缺乏与光学性能建立联系的频带误差定量评价方法;②现有功率谱密度方法在分析不同的确定性加工方法或者不同的工艺参数对频带误差及光学性能的影响时存在不足。为此,论文围绕确定性加工频带误差的评价与分析两方面展开研究,以达到为确定性加工频带误差的控制提供参考的目的。论文的研究工作包括以下几个部分:①在现有功率谱密度特征曲线的基础上,提出基于功率谱密度特征曲线的小波评价方法,在反映误差频谱特征、评价光学表面的同时,还可表达不合格频率在光学表面的分布,对确定性加工进行指导;②提出基于Harvey-Shack散射理论的小波评价方法,为建立确定性加工中频带误差与光学性能之间定量关系提供理论基础;③提出基于光学性能的确定性加工频带误差评价方法。利用基于Harvey-Shack散射理论的小波评价方法分析的实验结果,结合统计光学理论,对不同光学性能产生主要影响的频带误差进行理论探索,得出了频带误差对光学性能的影响规律;④提出基于小波理论的确定性加工频带误差分析方法,分析了加工工艺参数与元件表面频谱分布特征之间的关系,寻找敏感频率误差产生的原因,并将这一方法在确定性加工(重点是离子束加工和磁流变加工)及子孔径拼接测量中应用实验,得出一些初步结论;⑤提出基于光学性能的确定性加工频带误差分析方法。将基于小波理论的频带误差分析方法与基于光学性能的频带误差评价方法相结合,将频带误差的评价穿插于误差的分析当中,为选择合适的确定性加工方法及合适的工艺参数,实现光学元件表面频带误差的合理控制提供参考,并通过三个实验介绍了其在确定性加工中的应用。更多还原

【Abstract】 Deterministic optical machining method improves the accuracy and the efficiency of optical machining compared with conventional optical manual fabrication. But there are many Mid- and High-spatial frequencies in deterministic machining. These spatial frequency band errors degrade optical performances significantly and are difficult to be controlled. The key reasons are:①There is lack of a quantitative specification method of frequency band errors relation to optical performances at present.②There are limitations in present Power Spectral Density (PSD) method to analyze the influence of different deterministic machining method or different technical parameters on frequency band errors and optical performances. The major research efforts in the dissertation are to offer the references for the control of frequency band errors in deterministic machining, and include the following points revolving about specification and analysis of frequency band errors in deterministic machining:①A wavelet specification method based on PSD Character Curve is proposed. The character of frequency errors spectrum is reflected and the optical surface is evaluated, moreover, the corresponding region of unqualified frequency is found to provide effective guidance for deterministic machining.②A wavelet specification method based on Harvey-Shack scattering theory is proposed. The quantitative relation between frequency band errors in deterministic machining and optical performances is established.③A specification method of frequency band errors in deterministic machining based on optical performances is proposed. According to the experiment result of the wavelet specification method based on Harvey-Shack scattering theory and statistical optics theory, the influences of frequency band errors on optical performances are obtained.④An analysis method of frequency band errors in deterministic machining based on wavelet theory is proposed. The relation between technical parameters and distribution of frequency spectrum of workpiece surface is established and the occurred reason of notable frequency error is found, and moreover, some elementary conclusions are obtained through some experiments in deterministic machining (emphasis on Ion Beam Figuring and Magnetorheological Finishing) and subaperture stitching test according to the analysis method.⑤An analysis method of frequency band errors in deterministic machining based on optical performances is proposed. The analysis method of frequency band errors based on wavelet theory and the specification method of frequency band errors based on optical performances are combined by inserting the specification method of frequency band errors in the analysis of errors, thereby the references for selecting appropriate deterministic machining method and appropriate technical parameters to control frequency band errors of optical surface are offered. Finally three maching experiments are introduced in deterministic machining by using this analysis method.更多还原