Design And Optimization Of2m-class Space Reflector Assemblies

With the continuous improvement of the accuracy of task demand for spaceexploration, the primary mirror of the space camera caliber greater demands. Withthe increasing of diameter, the mirror deformation due to its own weight and thechanges of temperature increased. According to the difference between groundenvironment and space environment, it is key technologies of large aperturereflectors that the design and optimization of the reflector and its support structure,enhance the mirror resistance to surface error degradation caused by its own weightand temperature changes.As for the study of2m-class reflector assemblies, the research work was carriedout in the following aspects:(1) On the foundation of the mathematical description of the optimizationproblem, it was introduced that the relevant techologies, such as Design ofExperiments (DOE), Approximation Models and optimization. That laid thetheoretical foundation for the next design analysis and optimization.(2) It was studied that the relationship between reflector deformation suffered tosome loads and the optical system, and rms value was regards as evaluation criteriaof reflector surface error. However, surface error rms value can not be used as afinite element commercial software optimization goal, account for the properties ofprocess integration and process automation capabilities, iSight, a computer aided optimization(CAO) software, was introduced to realize finite element modelupdating, calculation, optimization of the evaluation platform.(3) The triditional methold applied to support2m-class space reflectors was faraway from meetting the surface error requirements. This paper refered to multisupports proposal, and some basic theories was studied, such as the number andlocation of the large aperture reflector support points, the materials and structure ofthe reflector; Finally, classical theory formula was applied to determine supportlocations of2m-class space reflectors, and the preliminary proposal of naked mirrorstructure was designed.(4) Account for the limitation of multi supports from classical theory formula,RSM(Response Surface Methodology) is applied to probe the optimum of supportslocation, and make clearly the relationship between surface error and varities, suchas diameter, center thickness and the location of supports mirror-shaped precisionrms and support points position. According to some project requirements, a reflectorwith2m diameter is studied and compared to the preliminary design. As the result ofoptimization, reflector structure with better surface accuracy and stability received(5) The overall design with same structure and similar materials is proposed, thebackplane and reflector gets the same deformations, reducing the dependence on aflexible structure, improve reflector assmblity environmental adaptability.(6) Due to mechanical environments and space thermal environments, thedeformaction of large aperature reflectors cannot meet the demand optical system, itwas proposed that it was the major reason that the identical flexures with differentloads leads to different deformation. With the RSM, the stiffness of flexure isoptimization, and the large aperturereflector Assemblies got a sound surface error.Using response surface approximation model study on the the mirror nakedMirror optimal support for flexible structure stiffness optimization is to get a soundmirror surface accuracy, the results are significant to engineering.