Research On A Single Alternating Light Field Time Grating Linear Displacement Sensor

As an important measurement of national industrial competitiveness and comprehensive national strength,high-precision displacement measurement is widely used in some national major engineering area such as aerospace industry,national defense and military industry,ultra-precision NC machining industry.With high precision,large range,high stability,high resolution and non-contact mode,optical displacement measurement has held a dominant position in the field of high precision measurement.Traditional optical measuring instruments are difficult to manufacture,complicated and expensive.Furthermore,in the previous research,the size of measuring head could scarcely be integrated,and the light source characteristics are different.Thus,a single light field time grating linear displacement sensor is designed in the paper to achieve high precision displacement measurement by single illuminant and low level manufacturing process.The main research contents are as follows:(1)The structure difference between the multiple alternating light field time grating and the single alternating light field time grating are compared and discussed.The sensing mechanism of single alternating light field time grating is expounded and derived in detail.(2)According to the structure of single alternating light field time grating,the simulation model is established,the light field distribution is calculated quantitatively,and the critical factor of measuring error are analyzed in detail.(3)Based on the sensing mechanism of single alternating light field time grating,a measurement system of single alternating light field time grating is designed,including the design of polar plate structure and installed structure,the excitation hardware circuit and the acquisition hardware circuit,and the software realized method of excitation signal and programmable digital potentiometer using FPGA.(4)The experimental platform of single alternating light field time grating is built,and the excitatory signal and the travelling wave signal were tested respectively.The measurement error is corrected according to the error model analysis.The experiment result showed that in the measuring range of 60 mm,the measuring error of prototype are controlled within ±0.4?m with grid spacing of 0.6mm,which verify the feasibility that using single illuminant and low level manufacturing process to achieve high precision displacement measurement.In summary,the correctness of the basic theory of single alternating light field time grating measurement is verified via the derivation and analysis of theory model,the design and debug of experimental installation,and the test and confirmation of experimental system,which lays a solid foundation for the research of high speed and high precision light field type time-grating displacement senor.