Research On Active Optical Micro-displacement Sensor And Its Testing System

The Active Optical System combines automatic control and precision mechanical technology,and is often used to realize the deformation of large-aperture splicing mirrors in astronomical telescopes,requiring real-time detection of small displacements between submirrors.Aiming at the problem of micro-displacement detection in splicing mirror technology,a capacitive sensor circuit based on the differential pulse width modulation method and a microdisplacement generating device for sensor debugging were designed.Based on the comparison of various capacitance detection methods,a capacitance detection circuit based on the differential pulse width modulation method,which outputs width modulation pulses with the change of the differential capacitance,and a low-pass filter circuit to extract the effective pulse value were designed.With the high-precision analog-to-digital conversion chip ADS1256 as the core,the analog-to-digital conversion module was designed,and the STM32 single-chip microcomputer was used to realize the sampling of analog signals.The data processed by the single-chip microcomputer is transmitted to the upper computer through the serial port while being displayed on the LCD screen for storage and display.At the same time,a micro-displacement generating device based on high-precision stepping motor and STM32 single-chip microcomputer and the control scheme of the displacement generating device were designed.Experiments on the capacitive sensor and the displacement generating device show that both of them can work normally,basically reaching the expected design goal.