Design Of A Displacement Measurement System Based On Dual-grating Interference

With the development of modern manufacturing toward high precisionlevel,high-precision displacement measurement sensor with a wide measurement range isneeded.The displacement sensor based on the principle of double diffraction gratinginterference is introduced in this paper. This kind of sensor has advantages of largemeasurement range and high accuracy,which is practical valuable.The measurement principle of the dual-grating interferometer displacement sensor isanalyzed.The principle is explained and simulated with ZEMAX.At the same time,the lightintensity distribution in the interference field is studied based on the angular spectrumtheory.Simulation and derivation results verify the feasibility of the measuring principleAccording to the measurement features and demands of the dual-grating interferencemeasurement sensor,the optical system and mechanical system of the sensor aredeveloped,based on software simulation and theoretical derivation.In addition,signal processing circuits for interference fringes are designed.A photoelectricdetector is adopted to convert the fringe signals to electric signals.Series of voltageadjustment and signal amplification circuits are developed to obtain two Sinusoidal signalswhose amplitude are equal and phase are orthogonal.Analog multiplier is used to achievehardware two subdivision.The traditional hysteresis comparator shaping circuit is improvedfor convenience of adjustment.At last,fringe counting circuit, signal acquisition circuit,software segment circuit and results show circuit based on MCU are designed to obtain themeasurement results.Testing experiment is carried out based on the dual-grating interferometer displacementsensor.The factors which may result in displacement measurements errors of dual-gratingsensors and the effect of these factors on the results are studied,and suggestion forimprovement are proposed.