The measurement of five degrees-of-freedom (5-DOF) error motions, including radial, axial, and tilt motions, is crucial for ultra-precision rotary axes, which are key components of ultra-precision machine tools and instrumentation. In this study, we propose an interference-enhanced micro-vision technique to concurrently derive the 5-DOF error motions from a single-shot two-dimensional image, which was captured by a standard industrial camera equipped with an interference objective lens. By consolidating the essential features into a single optical path, the interference-enhanced micro-vision technique ingeniously merges machine micro-vision and modified white-light interference to detect in-plane and out-of-plane motions. Numerical simulations demonstrated, the basic principle for deriving the 5-DOF error motions, and the magnification of objective lens had inconsistent effects on the measurement accuracy for the radial and tilt motions, i.e. higher magnification led to higher radial accuracy but lower tilt accuracy. As practical application, the error motion detection capability was demonstrated by simultaneously measuring the 5-DOF synchronous and asynchronous error motions for a typical air bearing spindle at rotation speeds of 8.33, 108.33, and 308.33 rpm. The synchronous errors were nearly identical at various spindle speeds. However, because of system dynamics, increased vibrations were observed to be superimposed on the basic tilt error motions as the spindle speeds increased, which were verified by the vibration marks imprinted on the turned surfaces. For the 5-DOF motion measurements, the least-square fitting using large-volume edge and greyscale data of the captured image enabled super-high resolutions, despite using a camera with a relatively large pixel size and low bit depth. These results demonstrate that the proposed interference-enhanced micro-vision technique is a simple and effective tool for measuring spatial error motions in ultra-precision rotary axes.

中文翻译：

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基于干涉增强微视觉的超精密旋转轴五自由度误差运动单次成像


五自由度 (5-DOF) 误差运动（包括径向、轴向和倾斜运动）的测量对于超精密旋转轴至关重要，而超精密旋转轴是超精密机床和仪器仪表的关键部件。在本研究中，我们提出了一种干涉增强微视觉技术，可以从单次拍摄的二维图像中同时导出 5 自由度误差运动，该图像是由配备干涉物镜的标准工业相机捕获的。通过将基本特征整合到单个光路中，干涉增强型微视觉技术巧妙地融合了机器微视觉和改进的白光干涉，以检测面内和面外运动。数值模拟表明，推导五自由度误差运动的基本原理以及物镜的放大倍数对径向运动和倾斜运动的测量精度的影响不一致，即放大倍数越高，径向精度越高，但倾斜精度越低。作为实际应用，通过同时测量典型空气轴承主轴在 8.33、108.33 和 308.33 rpm 转速下的 5 自由度同步和异步误差运动，证明了误差运动检测能力。不同主轴速度下的同步误差几乎相同。然而，由于系统动力学的原因，随着主轴速度的增加，观察到振动增加叠加在基本倾斜误差运动上，这通过车削表面上压印的振动标记得到了验证。 对于五自由度运动测量，尽管使用具有相对较大像素尺寸和较低位深度的相机，但使用捕获图像的大量边缘和灰度数据的最小二乘拟合实现了超高分辨率。这些结果表明，所提出的干涉增强微视觉技术是测量超精密旋转轴空间误差运动的简单而有效的工具。