Research On Signal Processing And Calibration Of Spectral Confocal Displacement Sensor

Spectral confocal displacement sensor is a non-contact displacement sensor be widely used in advanced manufacturing field with many advantages,such as small size,high precision and fast speed.At present,spectral confocal displacement sensor is almost monopolized by foreign companies in the market.So it is of great significance to study the key technologies of spectral confocal displacement sensor,realize the self-manufacturing of spectral confocal sensor and further improve its performance level.This paper focuses on the signal processing and calibration technology of spectral confocal displacement sensor.The main contents are as follows:(1)The influence of uneven distribution of light intensity,dark signal and noise on peak wavelength extraction of spectral confocal displacement sensor signal is analyzed.Aiming at the problem that peak extraction algorithm can not take into account both efficiency and accuracy,a peak wavelength extraction algorithm based on mean-shift theory is proposed.The experimental results show that the accuracy of this method is equal to that of Gauss fitting method,and the efficiency is improved by 73 times.(2)Aiming at the non-linear relationship between peak wavelength and displacement of spectral confocal displacement sensor signal,a calibration method based on piecewise fitting of characteristic curve is proposed,which effectively improves the calibration accuracy.(3)Aiming at the problem that the tilt of the measured target surface will affect the accuracy of the sensor,a compensation method based on calibration model of experimental test is proposed,which reduces the influence of the tilt of the target surface on the measurement of spectral confocal displacement.The maximum measurement error before compensation is 8 ?m,and the measurement error after compensation is reduced to 2 ?m.The compensation effect is obvious.(4)An experimental device for measuring the performance of the spectral confocal displacement sensor was built,and the performance test was carried out.The validity of peak extraction and wavelength-displacement calibration of the spectral confocal signal was verified.