Design Of Objective Driver Control System For Focus Variation

Focus variation is an important optical measurement method.The objective positioning system plays an important role in the measurement system,since its positioning accuracy and response speed have great influence on the measurement accuracy and speed of the focus variation system.This thesis focuses on the research of high precision objective positioning control system and designs a VCM-based positioning system.Contents and achievements of this research are listed as follows:First,it designs a VCM-based and directly driven objective positioning control system and establishes a mathematical model for this system through analysis on Electromechanical model.Second,a fully simulated VCM drive circuit is designed in this thesis.The PID control parameters of the current loop are determined by MATLAB simulation.The rationality of the design of the whole drive circuit is verified by Multism software,and upon this basis VCM drive plate is also produced.Third,a motion control card based on STM32F103 is designed.It uses USB and host computer communication in integrating high precision DA signal output,collecting signals from laser interferometric displacement sensors,programming the position loop control algorithm based on variable integral PID and setting up relevant parameters.Finally,the research also conducts experiments on current loop driving circuit and integrated objective lens positioning system,The experiment results verify the validity of this design on control system.