| Space deployable antenna is an indispensable space equipment in aerospace engineering and mainly developed to large size,light quality and high precision.As a very potential structural form in the space deployable antenna,modular deployable antenna is mainly composed of several basic deployable units.In order to achieve seamless splicing and synchronous and smoothly expansion,it is necessary to do some exploration and research on the characteristics of the basic deployable units and splicing forms of the mechanism while designing the structure of the modularized deployable antenna.In this paper,a modular parabolic cylindrical antenna reflector is considered as the research object,and the deployment mechanism and cable net structures of the parabolic cylindrical antenna reflector is mainly studied.The specific research content and results are as follows:(1)The modeling method of space geometry of deployable mechanism of parabolic cylinder antenna reflector are studied.Summarized the existing basic deployable units,and a planar eight bar mechanism is adopted as the basic deployable unit of the parabolic cylinder antenna reflector deployment mechanism.The circular is fitted to the paraboloid,and the fiting circle equation of the deployable mechanism is obtained.The modular space geometry modeling of the parabolic cylinder antenna reflector deployment mechanism is carried out,and the key node coordinates of each module are obtained.The key nodes are numbered,and the connection topology of the key nodes of each module is determined.The space geometric model of the deployment mechanism is obtained.(2)The structure design and scale optimization design of the basic deployable units of the parabolic cylinder antenna reflector deployment mechanism are studied.With the planar eight bar mechanism as the basic unit of the parabolic cylindrical antenna deployment mechanism,the closed loop vector method is adopted to complete the position analysis of the mechanism position.And then taking the angle between the part length and the mechanism position of the basic deployable unit as the designing variable,minimizing the driving stroke and minimizing the maximum transmission angle of the mechanism as the optimal target,the scale optimal design of the basic deployable unit is carried out with the help of Isight optimization software,and the optimum parameter of the mechanism under the optimal target is obtained.The kinematics simulation and verification of the basic deployable unit and the whole expansion mechanism were carried out by using Adams software.The final result shows that the basic deployable unit having optimized can reach the driving stroke of 59.7 mm,the minimum transmission angle of 5.836 degrees and the expansion ratio of 33 to 1,and the basic units and the whole deployable mechanism can achieve synchronous and stable development.(3)The mesh design method and pretension design method are studied for cable net structures of parabolic cylindrical antenna reflector.The mesh of the cable net is designed by the quadrilateral double-layer cable net,and the geometrical model of the cable net structure is obtained.Based on the idea of force density,the pretension design of cable net structure is completed,and a set of pretension values which make the cable net structure have the certain rigidity and maintain regular shape is obtained.The finite element model of cable net structure is established in the Ansys software and performed the static analysis to obtain the error value of the surface. |
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