| Compared with the traditional wireless microwave communication,laser communication has the advantages of high data rate,high frequency,large communication capacity,large optical gain,small divergence angle,strong anti-interference and anti-interception ability.Its system is small size,light weight and low power consumption.And it's very suitable for communication in space environment.The ground terminal structure of laser communication is an important part of the satellite-to-ground laser communication experiment.The excellent optical axis stability and mirror surface quality of its primary mirror and support structure can make laser communication more stable and reliable.Based on the application background of satellite-to-ground laser communication,the primary mirror and its supporting structure of ground terminal for satellite-to-ground laser communication are researched in this paper.In order to ensure the stability of optical axis and mirror surface quality of the primary mirror structure,the following research contents are mainly carried out:Firstly,the ground terminal structure of the laser communication ground at home and abroad is analyzed.The primary mirror support methods are discussed and analyzed.The overall supporting plan of the primary mirror is determined based on the optical parameters of this paper.And the primary mirror surface evaluation method is analyzed and discussed.Secondly,according to the determined supporting plan of primary mirror,the parametric modeling of the supporting position of primary mirror is carried out by using integrated analysis method,and the approximate model of neural network is established.The optimum supporting position of primary mirror is obtained by parametric optimization,and the surface figure of primary mirror is calculated from 0 to 90 degrees.The supporting structure of the primary mirror is optimized and analyzed by finite element method.Thirdly,compared with different of the lightweight mirror,Based on the theory of multi-objective optimization and compromise programming method,the paper has established a mathematical model of multi-objective topology optimization considering multiple stiffness condition and minimization of the weight.And the lightweight design of the primary mirror is carried out.The size of the primary mirror after topology optimization is optimized twice.The mass of primary mirror is 6.9kg,and the RMS value is 2.77 nm when the optical axis is vertical.Compared with original modal,the primary mirror has lighter weight and higher surface figure.It can meet the target requirements,which verifies the feasibility of the method.Finally,the supporting structure bottom plate is optimized.The primary mirror and its supporting structure is assembled and the finite element model is established to carry out static and dynamic analysis.The analysis results show that the surface figure of the primary mirror meets the technical requirements and the minimum frequency meets the requirements. |
