Yu Hai, Wan Qiuhua, Lu Xinran, Zhao Changhai, Liang Lihui
Appl Opt. 2022 Jan 1;61(1):287-293. doi: 10.1364/AO.446859.
As the feedback link of a numerical control system, the measurement accuracy of absolute angular displacement measurements directly affects the control performance of a numerical control system. In previous research, angular displacement measurements based on dual image sensors can achieve higher measurement performance. However, the elimination of harmonic error by the dual image sensor is still limited. For this reason, this paper proposes an image-type angular displacement measurement method based on self-correction error compensation of three image sensors. First, the mathematical model of harmonic error is established, and the shortcomings of using dual image sensors to compensate the error are analyzed. Then, a high precision angular displacement measurement method based on three image sensors is proposed. Finally, the self-correction error compensation method of three image sensors is applied to the angular displacement measurement system, and the measurement performance is verified. The experimental results show that a measurement accuracy of 1.76 can be achieved on the circular grating with a diameter of 96 mm. In contrast, the dual image sensor can only achieve a measurement accuracy of 2.88. It is concluded that the odd number of image sensors can achieve higher measurement accuracy than the even number. This research lays a foundation for the realization of high precision image angular displacement measurement.
作为数控系统的反馈环节，绝对角位移测量的精度直接影响数控系统的控制性能。在以往的研究中，基于双图像传感器的角位移测量能够实现较高的测量性能。然而，双图像传感器对谐波误差的消除仍然有限。为此，本文提出一种基于三个图像传感器自校正误差补偿的图像型角位移测量方法。首先，建立谐波误差的数学模型，分析使用双图像传感器补偿误差的不足。然后，提出一种基于三个图像传感器的高精度角位移测量方法。最后，将三个图像传感器的自校正误差补偿方法应用于角位移测量系统，并验证其测量性能。实验结果表明，在直径为96mm的圆形光栅上可实现1.76的测量精度。相比之下，双图像传感器只能达到2.88的测量精度。得出奇数个图像传感器比偶数个图像传感器能实现更高测量精度的结论。该研究为实现高精度图像角位移测量奠定了基础。
