Design And Optimization On The Structure Of The Extra-wide Coverage Space Camera

As the continuous development of the science and technology and the continuousimprovement of the observation requirement, the space camera with high resolutionand extra-wide coverage is becoming the development tendency of the opticalremote sensor. The coverage width of space extra-wide coverage camera researchedin the paper is more than500km. The length-width ratio of the structure is close to1:1.2. Based on the structure characteristic, the mirror and frame of camera have tobe adjusted in the material and structure form, in order to reducing camera weight,enhancing structure stiffness and stability. Besides, the camera has to undergoexternal loads and environmental factors, such as manufacturing, assembling,transporting, launching and working process, which influence the imaging quality.Thus, according to optical structure characteristics of camera and designrequirements, the space camera with the large-aperture mirror and frame structure isresearched deeply.First, the evaluation method for the environmental characteristics and mechanicalresponse of space camera is presented, by introducing mechanical environmentsexperienced. The principal factor affected by contact stiffness is analyzedtheoretically, combining with finite element analysis principle; a novel finite elementmodelling method for bolt joint is presented. And the efficiency and precision of dynamics analysis are improved by considering synthetically the influences of thecontact and bolt pre-tightening on structure stiffness matrixes.Second, the design basis of space camera mirror structure is described. Thematerial of mirror and support structure is selected, in accordance with performanceand manufacturability of materials. A novel design of flexible support structure and alight-weight design of the mirror are accomplished. The results of finite elementanalysis show that the design is reasonable, and the mirror has desirable properties,such as high specific stiffness, temperature suitability, which meets the imagingquality requirements.Third, the designing scheme of the integral frame and truss frame structure ispresented. The influence of the angle between the girder poles on frame frequency isstudied, and the design and optimization on truss frame structure are completed,based on the principle of conservation of energy and Rayleigh algorithm unit forcemethod. Applying the high volume fraction SiC/Al composites with high specificstiffness and thermal stability, and constructing the interpolation model of SIMPmaterial, the integral frame structure is designed and optimized through settingconstraint condition and objective function. And finally the integral frame structureis designated by means of contrastive analysis.Fourth, the finite element analysis and mechanical testing are carried out and theinfluences of environmental factors on the imaging quality are analyzed. The resultsshow that the space camera has good mechanics property and thermal stability, andthe dynamic response is in a reasonable range. The error between the finite elementanalysis and tests is small, which proves the rationality of structure design by finiteelement analysis method. And the structure design target of space camera with highspecific stiffness and light-weight is finally completed.