We studied the superiority of two different control methods for adaptive optics using the Shack-Hartmann Wave-Front Sensors (SHWFS) using a compact AO system (CRAO), which were developed at the Koyama Astronomical Observatory of Kyoto Sangyo University. Direct Gradient Control (DGC) method experimentally derives a control matrix that directly converts slope vectors to DM voltage vectors. Zernike Modal Control (ZMC) method generates a control matrix with two reconstruction matrices in modal representation for a Deformable Mirror (DM) and wavefront slope vectors obtained from the SHWFS images.We simulated the various atmospheric conditions with windspeed at r0=3.7cm by laboratory experiments and investigated the AO performances (FWHM and residual WFE) between these two methods.The results showed that at wind speeds V>12m/s, there was no difference among the methods, and the temporal error was dominant. V<12m/s, ZMC method performance improves as the number of Fringe Zernike terms, and it was found that the use of up to 36 terms produces better performance than DGC method. The reason for the worse DGC method was found to be that the applied voltage calculated for the TT-arm is large and the PSF is not stable.
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