【摘要】 空间光学相机是高精度系统,其主镜由重复伸展机构支撑到位并实现系统成像。为了提高空间光学相机可重复展收机构的精度,基于Miura折纸原理提出薄膜防护罩折叠方法并进行了参数分析。采用NX/SST仿真软件分析了伸展机构有无防护罩包覆的温度场,研究了主镜安装面在不同温度梯度下的变形规律,利用伸展机构防护罩样机进行了伸展机构可重复展收实验。结果表明本文设计的可重复折展薄膜防护罩的展开角θ_A=120°时,结构已完成接近85%的展开,此时模型形状依然规整,验证了防护罩的随动重复展收功能。通过热分析发现,有防护罩时伸展机构最高温度为12℃,最低温度为3.5℃,与无防护罩相比,最高温度降低了22℃,最低温度提高了51.5℃,防护罩有效降低了伸展机构的温度梯度。实验结果表明,伸展机构在进行了10次重复展开试验后,在X方向重复精度平均值的绝对值为0.002 16mm,Y方向为0.005 96 mm,Z方向为0.003 48 mm。本文设计的伸展机构具有较高的重复展收精度,基于折纸原理设计的薄膜防护罩具有良好的可重复展收、遮光和热控效果,可以有效保证光学相机在空间环境的应用。更多还原

【Abstract】 The space optical camera is a high-precision system,and its primary mirror is supported by the repeatable development and collapse mechanism to achieve system imaging. To improve the accuracy of a space optical camera’s repeatable development and collapse mechanism,the folding method of the membrane protective cover is proposed,and a parameter analysis is conducted based on the Miura origami principle. The NX/SST simulation software is used to calculate the temperature field of the repeatable development and collapse mechanism with and without the membrane protective cover. Further,the deformation law of the primary mirror mounting surface under different temperature gradients is studied. The extension mechanism membrane protective cover prototype is used to perform the repeatable development and collapse experiment of the extension mechanism. The results show that when the expansion angle of the repeatable expansion and collapse film protective cover,designed in this study,is 120°,the structure has completed nearly 85% of the expansion. Moreover,the shape of the model is still regular at this time,which verifies the passively repeatable development and collapse function of the protective cover. Through thermal analysis,it is found that the maximum temperature of the camera’s internal extension mechanism with a protective cover is 12℃,and the minimum temperature is 3. 5 ℃. Compared with the no protective cover case,the maximum temperature is reduced by 22 ℃,and the minimum temperature is increased by 51. 5 ℃. The protective cover effectively reduces the temperature gradient of the extension mechanism.The experimental results show that after 10 repeated development tests of the extension mechanism,the average repeatability accuracy absolute value in the X,Y,and Z direction are 0. 002 16 mm,0. 005 96 mm,and 0. 003 48 mm,respectively. The extension mechanism designed in the study has a high repeatable expansion accuracy,and the film protective cover designed based on the origami principle has good repeatable development and collapse,shading,and thermal control effects,which can effectively ensure the application of the optical cameras in space environments.更多还原