Research On Ultra-Lightweight Method Of Small Space Optical Imaging System

With the development of space technology,space remote sensing camera can develop rapidly.Space camera plays an important role in geodesy,resource exploration,navigation and positioning,national defense reconnaissance and other fields.Since the 1980 s,the miniaturization of satellites has become the development trend of space technology.So far,small satellites have played an important role in surveillance,reconnaissance,navigation,communication mapping and meteorology because of their advantages such as light weight,small size,low manufacturing cost and short R & D cycle.Therefore,the lightweight of space structure and comprehensive performance is an inevitable requirement for the application of small and light remote sensing satellites,and also an urgent need for the development of small and light high-resolution space cameras.It is of great significance to realize high lightweight and performance optimization of optical structures.With the development of small-scale space optical imaging system,the research of microsatellites in China is in a rapid development stage.In order to reduce the launch cost,reduce the volume and gravity of the whole machine,and solve the practical engineering problems,the following work is carried out for a small space optical imaging system.1.Research on the lightweight design of space camera with coaxial TMA optical system.Including the space mirror material,the mirror support mode,the main support structure and the development status and trend of the space imaging system.2.The optical design requirements of a small space imaging system are described,and the space use environment of the imaging system is analyzed,including static environment and dynamic environment,to provide ideas for optimization methods.3.According to the requirements of optical design tolerance,ultra-lightweight optimization design is carried out for primary,secondary and tertiary mirrors in small-scale space imaging system.Taking the lightest mirror quality as the optimization objective,the multi-objective optimization method is used to get the optimal solution of the mirror.At the same time,the supporting mechanism of the mirror is explored,the mechanical analysis of the flexible structure is carried out,and a new supporting structure of the mirror is designed,in which the accuracy of the main mirror surface is high It is better than the requirement of 40%,the secondary / tertiary mirror is better than the requirement of 50%,and the lightweight rate of the primary mirror is over 92%,which meets the requirement of ultra-lightweight.4.By comparing the existing space main support materials,carbon fiber(M40)is selected as the first choice material to design the secondary mirror truss system.According to the ultra-lightweight design requirements,a new secondary mirror truss system is designed.The first-order resonant frequency is 210.099 Hz,and the secondary mirror type accuracy is better than the use requirements.This kind of truss has high stability and structural rigidity.5.The structure of the whole machine has good static and dynamic stiffness,meets the overall use requirements,and has the transmitter conditions;at the same time,the main mirror assembly is tested and verified,the results show that the super lightweight optimization design of the main mirror is consistent with the test results,and the super lightweight method of the main mirror is feasible,which can provide reference for the design of similar small space imaging system.The research of this subject provides theoretical support for the ultra-lightweight and back support of the small space optical imaging system,and technical support for the main support mechanism of the light small space camera.The experiment shows that the method and technical path proposed in this paper are feasible and have certain guiding significance and reference value.