Control Of Piezoelectric Deformable Mirror Based On Zernike Polynomials

Adaptive optics(AO)is a subject that emerging recently,using the phase conjugate compensation principle of DM to measure and compensate wavefront aberrations in real-time,eliminate the influence of atmospheric turbulence.Nowadays,AO are widely used in laser beam shaping,free space communication,biological microscope,retinal imaging and laser communications and other fields.Piezoelectric deformable mirror has the advantages of high bandwidth,large deformation,getting the favour of a large number of researchers,this experiment adopted piezoelectric deformable mirror.Based on DM of adaptive optics system control method research is an important research direction.In order to improve the control accuracy of piezoelectric deformable mirror and simplifying the control,It is proposed PID control algorithm based on the Zernike polynomials,realize the closed-loop feedback control of the piezoelectric deformable mirror.This paper adopts the piezoelectric deformable mirror control method as the research object,and do the following several aspects of research content.(1)Firstly,it is studied the influence function matrix pseudo-inverse algorithm and PID closed-loop control algorithm,the direct closed-loop feedback control model and the PID closed-loop feedback control model based on Zernike polynomials is established.(2)Secondly,the AO closed-loop control system was built in laboratory,mainly includes the hardware platform and software platformthe 62 element piezoelectric deformable mirror was used to build AO test platfrom,and programmed the drive control system based on LabVIEW,it is realized the real-time display of hartmann wavefront sensor and the real-time precise control of piezoelectric deformable mirror.(3)Finally,the outside dynamic disturbance was simulated by phase plate,the AO test platform and driving control system was used to realized real-time closed-loop feedback correction.Experimental results show that the rotation speed of phase plate is 6 r/min,using the PID algorithm the RMS of the residual error is 0.032?m,compared with only using SVD algorithm calibration precision is improved by 50.8%.When speeding up the phase plate and the same correction aberration disturbances before correcting,correction effect and the effect of PID control algorithm is commonly weak,when the rotating speed of phase plate is 18 r/min,the PID correction effect than using improved SVD algorithm only 26.9%.The rotating speed of phase plate and external disturbances is considered under the same conditions,the PID control algorithm based on Zernike polynomial of wavefront aberration correction,than adopting the method of direct feedback correction precision is improved by about 50%.It is proved that the PID control algorithm based on the Zernike polynomial can improve the the outside dynamic aberration correction precision of piezoelectric deformable mirror and simplify control system.