Design And Implementation Of Single-layer Diffraction Grating Displacement Sensor

Micro-displacement measurement technology is a prerequisite for current precision machining technology,precision assembly process and micro-scale observation,and its development level reflects a country's industrial strength and technical level.At present,the rapid development of micro / nano displacement measurement technology has promoted the rapid development of high-tech fields such as CNC manufacturing,aerospace and military equipment.As one of the current mainstream nano-displacement detection technologies,optical displacement detection has attracted wide attention from researchers in various countries with its advantages of high precision,high resolution,and immunity to electromagnetic interference.Research institutions and universities are improving accuracy and improving resolution.Great efforts have been made.In this paper,the grating is used as a spectroscopic component.By improving the optical structure of the existing single-layer diffraction grating displacement sensor,the output light intensity is expanded from a single-channel sinusoidal signal to four-way orthogonal sinusoidal output,and the resolution of the subdivision interpolation circuit is improved.First,through combing and analyzing the advantages and disadvantages of the current mainstream grating displacement measurement technology,analyzing the current mainstream grating displacement sensor design ideas,combined with the problem of small single-layer diffraction grating displacement sensor range,it is proposed to solve the problem Improvement plan.By using the method of polarization phase shift to realize the output of four orthogonal sinusoidal signals,while improving the range of the sensor,the displacement resolution can be improved by using the more general subdivision interpolation method.Then,use Simulink to model and simulate the arctangent interpolation algorithm,and analyze how to use the arctangent algorithm to improve the linearity and range of the sensor's sine and cosine output signals.At the same time,due to the inevitable existence of amplitude error,offset error and phase error in the output signal,a quantitative analysis of the arctangent interpolation error caused by various errors in the output signal is performed.Finally,by designing an offset conditioning circuit,a phase conditioning circuit,and an amplitude conditioning circuit,the error of the output signal is adjusted.The experiment of arctangent algorithm was verified by subdivision interpolation chip,and the standard sine and cosine signal was output by the signal generator,which can realize 10000 times interpolation subdivision.Finally,through the construction of the optical path and the interpolation of the subdivision of the output signal of the optical path,it is possible to achieve a displacement resolution of 2.54 nm while extending the range.