A multi-axis position sensor using a 2-D color-coded binary scale (CCBS) is proposed for measuring absolute 2-D planar position and orientation in a full angle range. Since a color-encoding method provides higher information density with multiple color channels, two absolute position codes and incremental scale patterns could be encoded in the 2-D CCBS using three color channels. Therefore, the absolute position value was obtained with high efficiency and robustness by processing three color channel images of the CCBS separately, and the measurement range of orientation was also extended to 360° using the relationship of two absolute position codes. The proposed method was implemented as a sensor module composed of an imaging lens, a board-level camera, and the CCBS on a flat panel display. The performance of the prototype sensor was evaluated by comparing with a laser interferometer and an angle encoder. The position sensor could measure 0.5- $\mu \text{m}$ linear and 0.005° angular displacements clearly. The repeatability was smaller than $0.13~\mu \text{m}$ , but the positional error of the CCBS increased the measurement errors up to $3.1~\mu \text{m}$ when the sensor was evaluated over 24 mm $\times24$ mm range. The full angle orientation was measured successfully with the accuracy of 0.02°.

中文翻译：

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使用二维彩色编码二进制标尺的绝对平面位置和全角方向传感器

提出了一种使用二维彩色编码二进制标度 (CCBS) 的多轴位置传感器，用于测量全角度范围内的绝对二维平面位置和方向。由于颜色编码方法通过多个颜色通道提供更高的信息密度，因此可以使用三个颜色通道在二维 CCBS 中编码两个绝对位置代码和增量比例模式。因此，通过分别处理CCBS的三个彩色通道图像，高效、鲁棒地获得了绝对位置值，并且利用两个绝对位置码的关系将方向的测量范围也扩展到了360°。所提出的方法被实现为由成像镜头、板级相机和平板显示器上的 CCBS 组成的传感器模块。通过与激光干涉仪和角度编码器的比较来评估原型传感器的性能。位置传感器可以测量 0.5- $\mu \text{m}$ 线性和 0.005° 角位移清晰。重复性小于 $0.13~\mu \text{m}$ ，但 CCBS 的位置误差使测量误差增加到 $3.1~\mu \text{m}$ 当传感器被评估超过 24 毫米时 $\times24$ 毫米范围。以0.02°的精度成功测量了全角定向。