| With the advantages of high gain,strong directivity and easy automatic beam scanning,parabolic cylindrical antenna has become one of the main development directions of space-borne antennas.The existing parabolic cylindrical antennas have the problems of high area density and low storage ratio,which restrict the wide application of large parabolic cylindrical antenna in the space field.In this paper,a cable-rib tensioned parabolic cylindrical deployable antenna is proposed by combining the advantages of high stiffness to mass ratio and simple structure of the tensegrity structure,and the key issues such as structural modeling and analysis,form-finding design,pre-optimization design for space environment,feed array design and software platform development of the parabolic cylindrical antenna are thoroughly studied.The main works can be described as follows:1.A design scheme of cable-rib tensioned parabolic cylindrical deployable antenna is proposed.Firstly,the parabolic cylindrical antenna adopts simple parallel four-bar mechanisms to construct the basic deployment unit,and the cylindrical direction dimension can be easily extended by modularization,which has obvious advantages in storage ratio and area density.Then,the geometric modeling process of antenna deployment mechanism is studied systematically,and the corresponding relationship between rod dimensions and antenna geometric characteristic parameters is established.A synchronous deployment method of multi-module parabolic cylindrical antenna driven by torsion spring and driving cable considering the influence of cable net tension is proposed.Finally,the kinematics analysis model of the parabolic cylindrical antenna is established,and the motion characteristics of the end of the mechanism corresponding to acceleration-constant speed-deceleration state are obtained,which verifies the feasibility of the scheme.2.A form-finding design method for cable-truss composite structures considering the geometric nonlinearity of trusses is presented.Firstly,through systematically considering relationshape between the cable network and flexible truss,a method for calculating the equilibrium state of the mesh antenna suitable for the geometric nonlinearity of the beam element is established by using the Newton-Raphson iterative method,and the sensitivity matrix of the cable net nodes and element length with respect to the force density in the equilibrium state is derived.Then,a double-layer cyclic iterative form-finding design method for mesh antennas is proposed.The inner cycle improves the form-finding design efficiency using the linear equilibrium equation and the sensitivity matrix.The outer cycle improves the form-finding design accuracy by considering the geometric nonlinearity of the trusses.The simulation results show that the proposed method has good versatility and has good design results for cable net-truss structures such as parabolic cylindrical antenna and ring antenna.3.A pre-optimization design method of parabolic cylindrical antenna considering space thermal environment loads is presented.Firstly,the equilibrium equation of mesh antenna system under space thermal loads is established based on finite element theory and force density equation.Due to the complexity of directly analyzing the influence of thermal loads on the entire mesh antenna,a research strategy of applying thermal loads step by step from flexible truss to cable network is adopted,and the force density increment equation of cable net under space thermal loads is derived.Then,taking the force density vector of the cable net as the design variable and the square sum of the thermal deformation of the reflector nodes as the objective function,a pre-optimization design model considering the space thermal loads is established,which meets the accuracy requirements of the reflector surface in the whole temperature interval.4.The prototype software for shape analysis and deployment process dynamics analysis of parabolic cylindrical antenna is developed.Based on the basic principle,structural characteristics and service environment of parabolic cylindrical antenna,the design flow of morphological analysis software and deployment process dynamic analysis software is determined.Several key technologies in the development of prototype software platforms have been broken through,realizing the parameterization,integration and rapidity of parabolic cylindrical antenna modeling and simulation analysis,and obviously improving the efficiency of parabolic cylindrical antenna research and development.5.The prototype model design and experimental research of the parabolic cylindrical antenna are carried out.Firstly,based on the model dimensions and form-finding design results of the antenna prototype,the deployable truss members,joints and flexible cable-network structures are designed and manufactured,and then the envelope dimensions of the parabolic cylindrical antenna are obtained.Then,a set of detachable ground support device for the prototype of parabolic cylindrical antenna is designed.Through repeated deployment experiments on the parabolic cylindrical antenna prototype,driving cable tension testing,and reflective surface accuracy measurement,the effectiveness of relevant theories for parabolic cylindrical antenna design was verified. |
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