Research On Displacement Sensor Based On DVD Reader

Precision measurement is the basis of precision machining and plays an important role in ensuring advanced manufacturing technology.With the development of advanced manufacturing technology,high-precision displacement sensors are facing a wider demand.The DVD reader is the core component on the optical driver of the optical disc signal tracking and reading,with high sensing accuracy and low cost.It is practical to develop the displacement sensor with the existing structure of the reader combined with the hardware and software design for precision measurement.This paper focuses on the development of DVD reader and develops displacement sensors.The main work is as follows:I.The DVD reader focus error signal acquisition circuit and the voice coil motor drive control circuit are designed.The focus error signal acquisition is given to the voice coil motor servo feedback control to realize the self-focusing of the DVD reader,and the displacement is reading by the voice coil motor control voltage.II.Based on the simulation analysis of the parameter identification effects of least squares method,extremum method and genetic algorithm,the identification method of dynamic characteristics of voice coil motor with initial identification of extreme value method and re-identification of genetic algorithm is proposed.The parameter identification of the voice coil motor system is realized after completing the step response experiment of the voice coil motor system based on the focus error signal of the DVD reader.III.On the basis of parameter identification,PID parameter tuning is completed by experiment and trial method in Simulink environment.Then with experiments PID control parameters are optimized.An integral saturation separation algorithm is proposed to prevent the system overshoot from exceeding the linear range of the focus error signal during the control process which can result in control failure.IV.The relationship between sensor voltage and displacement is measured by experiment,then the sensor hysteresis effect was compensated by Preisach model.V.The sensor performance test experiment was completed,which verified its good accuracy characteristics.