Study Of The Filtering System For The Active Optical Micro-displacement Sensor Based On ZYNQ Platform

Active optical technology is widely used in astronomical telescopes as a wavefront correction technology,which can eliminate the deformation of the optical system and support frame caused by environmental factors.The precise measurement of the axial displacement between the lens by the displacement sensor is the core of real-time correction of the active optical system.In the application background of active optical system,this paper specifically designed a sensor filtering system based on the ZYNQ platform for dual differential variable area capacitive sensors.This paper designed a digital filtering system for the sensor by analying plate structure of the capacitive displacement sensor and the signal-to-noise characteristics of the analog circuit.Adopting the BP neural network filtering algorithm to aim the characteristics of complex system signal and unknown noise,relied on the network adaptive ability and function approximation,through MATLAB simulation curve fitting and Pearson correlation coefficient comparison,the paper proved that the filtering algorithm can filter and denoise the sensor displacement signal.The system adopted a collaborative design method for embedded system software and hardware,taking ZYNQ7000 series XC7Z020-2CLG400 I as the core,using ARM processor to control FPGA for high-speed data interaction,and using Vivado design tools to complete the construction of the filtering system.With AD7606 as an analog-to-digital converter,the realization of the signal acquisition module was completed through the design idea of a state machine.With the BP filter algorithm was integrated with the median average filter algorithm,the signal processing module was implemented by filtering the collected signals.Through the design of VDMA,HDMI and Qt interfaces,the implementation of data visualization module by the filtered signals were displayed in real time.Through the design of baud rate control and serial port transmission,the data transmission and storage module was completed by sending the data to the upper computer.Through the filtering system was run in the ZYNQ & petalinux embedded environment,combined with signal reproduction and measured results of precision displacement platform,it showed that the filtering system can achieve the purpose of extracting weak displacement signals under the background of strong noise.