Optimized Design Of The Topological Structure Of The Large-aperture Mirror Assembly

With the continuous improvement of the precision requirements of space observation satellites,the resolution requirements of space optical remote sensors are getting higher and higher,and the diameter of the mirrors is getting larger and larger,and the mirror shape is subject to conditions such as vacuum,gravity release,vibration and thermal cycling.The impact will also be greater.Therefore,for high-precision large-caliber mirrors,the light weight of the mirror body and the stable and reliable support structure are the keys to improving the observation capability of the space optical system.This subject studies the mirror body,support method,and support structure for a large-aperture mirror of 1m.According to the relevant parameters and design index requirements of the main mirror in an optical system,combined with traditional design methods,the open-back type is selected as the basic form of lightweight,and the triangular lightweight hole structure is selected.In order to achieve the high weight and weight of the mirror,the topology optimization method is adopted.The mirror density is used as a design variable,the mirror base frequency is used as the optimization target,and the shape RMS value and quality are used as constraints to optimize the design of the mirror.The mirror weight is 40.4kg,and the mirror surface shape is 0.001λ.Compared with the traditional optimization method,the topology optimization method has more advantages,and the weight reduction rate can reach 81%.In this paper,the support structure of the mirror is studied.Finally,a light and small flexible support structure is designed using a six-point support method on the back.In the design,finite element method was used to optimize the position of the support points to ensure the optimal mirror surface shape.In order to reduce the thermal stress between the mirror components,a flexible link was designed and verified by finite element.The finite element software was used to simulate the component.The static results showed that the reflector and the mirror component meet the requirements in the following three cases: 1g radial gravity,4℃ temperature rise,and 1g radial gravity + 4℃ temperature rise.The dynamic results show that the mirror assembly meets the requirements of strength and stiffness.The mirror and support structure are designed to meet the requirements.