Research On The Test Techniques And Drive Control Of The Segmented Mirror

The telescope’s aperture is made increasingly bigger with the growing demanding of thetesting ability of optical telescopes. Segmented mirror is developed to replace the verybeginning technique single primary mirror. Also, due to the fact that relative motion bysegments affects the surface during system operation, and therefore segmented mirror brought anew problem is how to ensure all of the segment coplane. This thesis analyzes the error ofsegment, investigates the error detection methods and actuator drive control. Theoreticalderivation and numerical simulation are also investigated.This thesis focuses on investigating the influence of piston error、tip-tilt error、gapsbetween segments、turned down/up segment edges and radius of curvature error on the systemimage quality, obtains the morphological changes of far-field spot by numerical simulation andinvestigates the Strehl ratio of curve. Determine the minimum system limit. Secondly, analyzesthe hole Fraunhofer diffraction theory, the diffraction templates between two segments underdifferent phase error template is obtained. Using image correlation algorithms to performmatching process to detected image to obtain phase error. Investigates the hole detectionmethod under the19segments and process the phase error between each segment bysimulations. Also, design a segmented mirror error detection method based on hole columndiaphragm or the corresponding arrangement of micro-lenses according to the circular aperturediffraction theory, obtain the white light diffraction spot model through ZEMAX modeling andsimulation. Through the analysis of the diffraction spot characteristics of F, d, C ray under thesituation that higher then half wavelength piston error, a new technique that usingpolychromatic light in detection process has been proposed, which increases the error detectionrange. Last, using three-dimensional coordinate transformation principle to obtain thecorrection matrix of single actuator under piston error and tilt error, and then get correctionmatrix of an arbitrary number of sub-mirror through the sub-mirror extensions, analyze PIDcontrol algorithm and fuzzy algorithm, compare the correction capabilities of fuzzy self-tuningPID control to traditional PID control, finally determine to use fuzzy self-tuning PID controlalgorithm to control the sub-mirror drive...