Research On The Topology Optimization And Support Of The Space Mirror

With the constant development of space optical technology, the space camera has played a decisive role in the field of space exploration, energy resource survey, weather forecast, military detective, nation building, marine research, etc. Mirror is an important part of the space optical remote sensor, and its surface shape accuracy has assignable influence upon the imaging quality of whole remote sensor. The large aperture mirror will become an important trend in the development of space optical remote sensor technology. However the increase of the primary mirror diameter makes the mirror self-weight deformation and thermal deformation caused by temperature change increase dramatically, and the launch and transport cost of the whole system will be greatly increased. So the design of the mirror must be as much as possible to reduce weight in guarantee under the premise of surface shape accuracy and structural stiffness.The traditional lightweight design is very difficult to satisfy these requirements at the same time. Therefore topology optimization design as a new type of lightweight technology of reflector is an important aspect of the current research of space camera technology. For topology optimization design of the rectangular mirror with dimensions of 800mm*240mm, and the flexible supporting structure reasonable for it, this article has mainly made the following aspects of work: Making topology optimization design of reflector, creating the reinforcing ribs based on the topology result, and carrying on further parameter optimization design on the reinforcing ribs with the finite element software, then we get the optimized model structure. At the same time, we establish three traditional lightweight structures with different shapes for comparison, then analyze performance parameter of several lightweight models. Support structure uses the flexible hinge which have been parameter optimization designed, so as to make the structure have good stiffness and thermal stability. In order to verify the reliability design of the mirror and its support mechanism, we build the finite element model of the whole assembly of the mirror, and analyze its mechanical analysis under different working conditions. The PV value and RMS value of the mirror deformation obtained through data Zernike polynomial fitting with the help of Matlab is the important evaluation criteria of the surface shape. The topology optimization model is much better than the traditional lightweight models whether in lightweight rate or the surface shape accuracy. Analyzing the mechanical property of the mirror assembly on flexible structure under different working conditions, the PV value of the mirror surface shape accuracy of is less thanλ/10,the RMS value is less thanλ/50(λ=632.8nm), and the first three order resonance frequency is much higher than the natural frequency of the structure. The results show that the mirror assembly can achieve sufficiently high static stiffness, dynamic stiffness and thermal stability, with sufficient ability to resist external environment disturbance, could be meaningful to other mirror assembly design.