Research On Signal Processing Technology Of Active Optical Micro-displacement Sensor Based On High-speed FPGA

With the wide application of the large and ultra large aperture telescope,there are increasing requirements on the combination technology of the splicing mirror and thin mirror in active optics.Therefore,it is proposed to study a new type of capacitive micro-displacement sensor to measure the displacement between the sub-mirrors accurately,and so as to adjust the sub-mirror to the ideal position.The sensor design mainly includes sensor principle analysis,signal acquisition and signal processing technology,this paper mainly researches the design of signal processing technology scheme by using the precision displacement sensor with high-speed FPGA.Based on the principle of the precision displacement sensor,this paper analyses the characteristics of the input signal,and carries out the overall analysis and design in analog signal processing,A/D converter controlling as well as digital signal processing and transmission.Moreover,since the sensor system cannot obtain the characteristics of noise signal,this paper focuses on the research and simulation analysis of the filtering methods which are suitable for this feature,including the median filtering algorithm,fixed-step adaptive filtering algorithm,as well as NLMS,SVSLMS and CLMS three variable-step self-Adaptive filtering algorithm.The median filter algorithm and the adaptive filter algorithm are designed and implemented by using FPGA.The CHIPSCOPE is used to observe the data variation and debugging online.In the final experiment,these data are qualitatively analyzed and quantitatively analyzed respectively.The digital signals are generated by MATLAB and stored in the FPGA chip ROM for digital signal processing and a combination simulation of CHIPSCOPE and MATLAB is used for data error calculation and analysis.Through the experiment,it can be seen that the system has good filtering effect.