Network Modeling And Optimization Design On Modular Deployable Antenna

In recent years, with the rapid development of the space industry, space deployable antenna is developing towards large-scale and high precision. On the basis of the research of deployable antenna, a mod ular mechanism is designed. According to design requirements, the basic unit is determined based on a synthesis method. Then select basic module to construct a large-scale antenna. In order to ensure the accuracy of the antenna surface, the least squares method is used to fit the paraboloid by sphere. And then establish the experimental model of deployable mechanism.In order that the deployable mechanism can fully expand and collapse, the expanded and collapsed status is analyzed and then the geometric relationship among length of each rod is determined. From the kinematic analysis of basic unit, it is showed that the expand speed need to be small to reduce the impact at the beginning. Programming in Matlab according to the principle of finite element method, the first ten natural frequencies of the mechanism is solved. Three form-finding methods which are commonly used in cable net design are introduced. Then the force density is selected after analysis and comparison. According to the characteristics of the mechanism, a method of three-way networking is used to design the cable net structure. The force density method is improved in order to meet the requirements of parabolic shape of the surface, and the calculations are carried out to find form of the cable net structure. The results show that the change of the force and the length of the cable net unit is relatively small, which means the cable net structure is available.When the antenna is fully extended, it forms a fixed structure. Therefore, this thesis presents the structure dynamic analysis. The first ten natural frequencies of the mechanism is obtained by modeling in A nsys. Compared with the calculation results of Matlab, the accuracy of programming algorithm is verified. Also, the mechanism vibration modes of the first ten natura l frequencies are obtained, which mainly reverse around the fixed end. Analyze the main factors which impact the structural dynamic properties, including materials and structural dimensions. Finally, sectional dimensions of the rod are optimized to make the weight lighter and the stiffness higher.