LI Haiteng， LI Xinghua
（State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin 300072, China）
Abstract： To solve the problems of small measurement range and poor accuracy of the spectral confocal non-contact probes, a four-piece lens group with a large measurement range is designed. Furthermore, a peak wavelength extraction algorithm based on the Adam algorithm and a piecewise fitting curve calibration method are also proposed. The lens group has a displacement measurement range of 4 500 μm in 470 nm-730 nm band. After the probe system is built using the lens group, it is experimentally verified that the displacement average measurement error using the Adam algorithm is 0.3 μm, which is 68.3% less than that of the centroid algorithm, 26.0% less than that of the traditional Gaussian fitting algorithm, and 24.3% less than that of the parabolic fitting algorithm, and at the same time, the displacement average measurement error using the piecewise fitting method is 92.4% less than that using the conventional polynomial fitting method. The experimental results show that the proposed probe system can achieve high-precision non-contact displacement measurement over a large range, which provides a theoretical and experimental basis for further research on high-precision displacement sensors based on spectral confocal technology.
Key words： spectral confocal; non-contact displacement measurement; peak wavelength extraction; Adam algorithm
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基于光谱共焦技术的高精度非接触测头
李海腾， 李杏华
（天津大学 精密测试技术及仪器国家重点实验室， 天津 300072）
摘要：为了解决光谱共焦非接触测头存在的量程较小、 精度差等问题， 设计了一种四片式大量程透镜组， 并提出了一种基于Adam算法的峰值波长提取算法和一种分段拟合曲线标定方法。 透镜组在大约470-730 nm波段内， 位移测量范围可达4 500 μm。 利用设计的透镜组搭建了测头系统， 通过实验验证了使用Adam算法的位移误差为0.3 μm， 比质心法减小了68.3%， 比传统高斯拟合法减小了26.0%， 比抛物线拟合法减小了24.3%， 而使用分段拟合方法的位移误差比使用传统多项式标定方法减小了92.4%。 实验结果表明， 所设计的测头系统可以实现较大量程的高精度非接触位移测量， 为进一步研究基于光谱共焦技术的高精度位移传感器提供了理论和实验依据。
关键词：光谱共焦； 非接触位移测量； 峰值波长提取； Adam算法
引用格式：LI Haiteng, LI Xinghua． High-precision non-contact probes based on spectral confocal technology． Journal of Measurement Science and Instrumentation， 2023， 14（3）： 270-279. DOI： 10．3969／j．issn．1674-8042．2023．03．003
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