Collaborative Research: Improved Freeform Measurement through Fiber-based Metrology

合作研究：通过基于光纤的计量改进自由形状测量

• 批准号: 1663210
• 负责人: ChaBum Lee
• 金额: $ 18.49万
• 依托单位: Tennessee Technological University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-15 至 2019-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1663210&HistoricalAwards=false
• 关键词: Collaborative; Research; Improved; Freeform; Measurement

Metrology is the art and science of measurement, and is central to advanced manufacturing. There is a critical need for improved metrology science in micro- and nano-scale ultra-precision manufacturing of freeform surfaces. The objective of this research is to improve measurement capabilities for such ultra-precision optical surfaces. This surface measurement is important not only after an optic device has been produced, but also during manufacturing to assess the process performance. Existing measurement methods suffer from fundamental errors that limit the achievable accuracy. Additionally, traditional techniques often interrupt the manufacturing process and limit productivity. In this research, on-machine metrology using a novel measurement strategy will be used to improve manufacturing capabilities for challenging optical components. The results of this work will be used to improve freeform measurement capabilities and will therefore lead to scientific advances in the optical, illumination, energy, aerospace, and biomedical fields. Other broader impacts include the two-week "Precision Engineering-Oriented Multidisciplinary Internship Program" at Tennessee Technological University, a permanent gallery that highlights precision engineering-based historic devices at the Cookeville Children's Museum, Cookeville, Tennessee, and "Project Engineering for Me (E4Me)" that targets middle school girls in the urban Charlotte-Mecklenburg school system. These educational efforts will expose K-12 students to STEM research and careers with a focus on precision engineering. The research objective is to eliminate cosine error in freeform surface measurement by integrating a novel fiber-optic sensor in an on-machine measurement configuration. Cosine error in surface profile measurement results from an angular misalignment between the measurement axis and the axis of motion and limits the measurement accuracy. This is especially true in measurements of Fresnel lenses, gratings, spherical/aspherical surfaces, and high-order polynomial surfaces, for example. Cosine error cannot be eliminated in current freeform surface measurement strategies because the measuring tools do not measure along the direction normal to the measurement plane. A novel methodology for freeform surfaces by integrating fiber optic techniques (autofocusing, Fizeau interferometry) in an on-machine configuration is planned. The project's approach also avoids machine tool error motions because the measurement path coincides with the machining path. By answering fundamental questions regarding the performance limits of the approach, it is expected that this research will produce new knowledge in high-precision, on-machine instrumentation.

计量学是测量的艺术和科学，是先进制造的核心。在自由曲面的微米级和纳米级超精密制造中迫切需要改进计量科学。这项研究的目的是提高此类超精密光学表面的测量能力。这种表面测量不仅在光学器件生产后很重要，而且在制造过程中评估工艺性能也很重要。现有的测量方法存在基本误差，限制了可达到的精度。此外，传统技术经常会中断制造过程并限制生产率。在这项研究中，采用新颖测量策略的机上计量将用于提高具有挑战性的光学元件的制造能力。这项工作的成果将用于提高自由形状测量能力，从而推动光学、照明、能源、航空航天和生物医学领域的科学进步。其他更广泛的影响包括田纳西理工大学为期两周的“面向精密工程的多学科实习计划”，这是一个永久画廊，在田纳西州库克维尔的库克维尔儿童博物馆重点展示基于精密工程的历史设备，以及“我的项目工程（ E4Me)”，针对夏洛特-梅克伦堡城市学校系统的中学生。这些教育工作将使 K-12 学生接触到以精密工程为重点的 STEM 研究和职业。研究目标是通过在机上测量配置中集成新型光纤传感器来消除自由曲面测量中的余弦误差。表面轮廓测量中的余弦误差是由测量轴和运动轴之间的角度失准引起的，并限制了测量精度。例如，在菲涅耳透镜、光栅、球面/非球面和高阶多项式表面的测量中尤其如此。在当前的自由曲面测量策略中无法消除余弦误差，因为测量工具不沿着垂直于测量平面的方向进行测量。计划通过将光纤技术（自动聚焦、斐索干涉测量）集成到机上配置中来实现自由曲面的新颖方法。该项目的方法还避免了机床误差运动，因为测量路径与加工路径重合。通过回答有关该方法性能限制的基本问题，预计这项研究将产生高精度机载仪器方面的新知识。