基于伪随机罗斯轨迹的光学表面中频误差抑制研究

Research on mid-frequency error suppression of optical surface based on pseudo-random Rose trajectory

光学表面的中频误差的控制长期以来一直是光学加工中的热点、难点问题。对于接触式的计算机控制光学表面成形技术,传统的加工路径如光栅式路径和螺旋线式路径通常会引入固有的中频误差,而新型的伪随机轨迹对机床的动态性能要求过高,使其难以普遍应用。基于对伪随机轨迹的研究,本文提出了利用伪随机罗斯轨迹对光学表面中频误差进行抑制的方法。在保证加工路径不重合和遍历工件表面的基础上,建立了伪随机罗斯轨迹的参数模型。针对传统的加工路径和伪随机罗斯轨迹进行了工艺对比实验,并对干涉结果进行功率谱密度分析。实验结果表明,三种路径对于低频误差均可以实现有效地抑制,而传统路径对于1/0.07 mm以上的频段误差会则会产生不良的影响,而伪随机罗斯轨迹则对于中频误差可以实现有效地抑制。

The control of mid-frequency error of optical surface has been a hot and difficult problem in optical processing field for a long time.For computer controlled optical surfacing technology,traditional processing paths such as grating path and spiral path usually introduce inherent mid-frequency frequency error,while the new pseudo-random path requires too much dynamic performance of machine tools to make it difficult to be widely used.Based on the study of pseudo-random trajectory,this paper proposes a method to suppress the mid-frequency error of optical surface by using pseudo-random Rose trajectory.On the basis of ensuring the non-coincidence of machining paths and traversing the optical surface,the parametric model of pseudo-random Rose trajectory is established.A comparison experiment was carried out between the traditional processing trajectory and pseudo-random Rose trajectory,and the interference results were analyzed by power spectral density.The experimental results show that the three paths can effectively suppress the low-frequency error,while the traditional path has a negative impact on the frequency band error of more than 1/0.07 mm,while the pseudo-random Rose trajectory can effectively suppress the mid-frequency error.