Research On Similarity And Topological Synthesis Of Large Deployable Antenna

The deployable large space antenna works in the space environments of weightless and large differences in temperatures, while its assembling, debugging and testing are on the ground. In order to ensure the antenna can deploy successfully and have perfect performances in space, plenty of experiments on the ground are necessary. However, it is impossible or arduous to carry out the experiments on the antenna because of the large aperture and the limitations of the ground environments, field, expenditures and testing equipments. It is feasible to use the scale model of the large antenna to achieve the performance testing. In this paper, the hoop truss deployable antenna is taken as an example and an analysis method of two-step approach is proposed. The first step is to analyze the similarity between the prototype and the model in the same environment. The different methods are adopted to derive the scaling laws according to the different performances of the antenna. The scaling laws of the driving force of the hoop truss deployable antenna are established through the differential equations, while the scaling laws of frequency are derived by the dimensional analysis method. Because the prototype and the scaled model are not completely similar, the effects of the distortions of structure parameters to the performances are taken into consideration. Then the scaling laws considering distortion coefficients are obtained. The second step is to analyze the performance relationships of the scale model in the different environments. It is much easier to do experiments on the scale model because of its smaller aperture. Based on the above work, we can predict the performance of prototype in the space according to the test data of the model on the ground.The space deployable structures are special topology-changing structures. In order to invent a superior and new type of space deployable structure, researching the methods of topological synthesis is the key. Because the space deployable structures and the metamorphic mechanisms both belong to the topology-changing structures, the topological synthesis of space deployable structures are studied with the help of metamorphic synthesis. The configuration of a space deployable structure is represented by adjacency matrix. The transformations among different configurations are implemented with the metamorphic synthesis methods of increasing the members, decreasing the members and changing the connection. Then the hybrid deployment different with the synchronous deployment and the configurations of the new deployable structures are obtained.