Truss Deployable Antenna Research Articles

Configuration synthesis of hoop truss deployable mechanisms for space antenna based on screw theory

Hoop truss deployable antenna can realize the communication and data transmission between satellite and earth, which is an important type of satellite antennas, and its configuration design is currently one of the research hotspots in the field of aerospace. Based on screw theory, configuration synthesis of the hoop truss deployable mechanisms for space antenna is studied in this paper. First, the constraint synthesis method based on screw theory is briefly described, the structure and folding principle of hoop truss deployable mechanism are analyzed. Then, structure decomposition of the hoop truss deployable mechanism is carried out, it is divided into upper hoop edge, lower hoop edge and connected rods. The movement features of the nodes are described by the prismatic (P) joints, configuration synthesis of the hoop edge mechanisms is carried out, and 18 kinds of constrained branch mechanisms are obtained, two kinds of constrained branch mechanisms are selected through analysis and optimization. Furthermore, hoop edge mechanisms are obtained by combining the constrained branch mechanisms, and five hoop truss deployable mechanisms are obtained through different connection combinations. Finally, simulation models of the five kinds of hoop truss deployable mechanism are built in Solidworks and Matlab software, the deployment processes are simulated and verified, and their characteristics are analyzed and discussed. The research in this paper provides a good reference for the configuration synthesis of spatial deployable mechanisms, and the hoop truss mechanisms obtained in this paper can be well applied in the field of aerospace.

Design and analysis of a truss deployable antenna mechanism based on a 3UU-3URU unit

Space deployable structures with large calibers, high accuracy, and large folding ratios are indispensable equipment in the aerospace field. Given that the single-DOF 3RR-3RRR deployable unit cannot be fully folded, this study proposes a 3UU-3URU deployable unit with two kinds of DOF: folding movement and orientation adjustment. First, based on the G-K formula, the DOF of the 3UU-3URU unit is analyzed. Then, the 3UU-3URU unit is used to construct a deployable truss antenna with a curved surface, and the DOF of the whole deployable antenna containing multiple 3UU-3URU units is calculated. The structural design of a deployable antenna with two loops is carried out with specific parameters and geometric relations. Next, a DOF simulation of a basic combination unit composed of three 3UU-3URU units is performed. Finally, a prototype of the basic combination unit is manufactured, and the DOF of the mechanism is experimentally verified.

Deployment Kinematic Analysis and Control of a New Hoop Truss Deployable Antenna

Firstly, based on the structural characteristics of a new type of hoop truss deployable antenna, this paper derives the motion transformation relation between two hoop modules by using the method of coordinate transformation, and establishes the general model for deployment kinematic analysis, which can be applied to analyze the position, velocity and acceleration of any point on the structure. Secondly, according to the relation between the driving cable and the hoop module, the motion planning of the hoop module is transformed into the motion control of the driving cable, which can realize the deploying position control of the antenna. Finally, numerical simulations show the control method can make the antenna smoothly deploy following the specified deployable motion.

Kinematic Characteristics and Dynamics Analysis of an Overconstrained Scissors Double-Hoop Truss Deployable Antenna Mechanism Based on Screw Theory

Large diameter space deployable antenna is the key equipment for communication and data transmission between spacecraft and base stations on earth. Based on the overconstrained scissors mechanism, a double-hoop truss deployable antenna mechanism is constructed in this paper, which can be used as the antenna support mechanism for satellites and other spacecraft, and its kinematic characteristics and dynamics are analyzed based on screw theory. First, the configuration and the overconstrained features of the double-hoop truss deployable mechanism are analyzed with the truss mechanism divided into a plurality of mechanism units. The geometric conditions for the double-hoop form are also investigated with the consideration of joint size effects. Then, based on the screw theory, the degree of freedom (DOF) of the mechanism is analyzed, showing that this mechanism has only one DOF. Next, the velocity and acceleration of the components in the mechanism are examined. Through the screw and screw derivatives operation, the velocities and accelerations of the components and the Jacobian matrixes are obtained. Finally, a dynamic model of the double-hoop truss deployable mechanism is established based on the Newton-Euler equation and the principle of virtual work, and this model is verified by the numerical calculation and simulation verification. The overconstrained scissors double-hoop truss deployable antenna mechanism proposed in this paper has a good application prospect in the field of space deployable antennas, and the theoretical analysis method in this paper can provide insights into other complex spatial deployable mechanisms.

Synthesis and optimization of modular deployable truss antenna reflector

PurposeThis paper aims to synthesize a modular deployable truss antenna with the lower degree of freedom (DOF) and larger folding ratio. Because of the advantages of this kind of new truss antenna, the modules that make up the antenna can be deployed together by the synchronous motor drivers instead of twist springs to realize the controllable deployment.Design/methodology/approachThe closed-loop branch equivalence method is proposed to synthesize the single DOF module and the large deployable reflector. The complex mechanism can be equivalently replaced by a simpler mechanism based on screw theory. The motion pairs are synthesized and optimized to make the curved surface achieve to the maximum folding ratio when the modular parabolic truss antenna is folded.FindingsThe results show that the 3(3RR-3RRR)-3RRR-3RRR planar module is a single DOF mechanism. Additionally, the adjacent parts of every two modules are connected with universal joints to obtain the new truss antenna when the modules are networked.Practical implicationsThe configuration of this new modular deployable truss antenna can be synthesized to design the structure, and the proposed method can be applied to other space multi-loop coupling mechanism and other spacecraft.Originality/valueThis paper presents an approach to synthesizing the motion pairs, as well as the DOF analysis. The results lay a foundation for the further analysis of the deployable control and dynamics of this kind of antenna. And the new modular truss antenna has a practical application in aerospace engineering.

Design of Deployable Antenna Based on SMPC

In order to get the deployable antenna with light weight but large size and high stiffness, this study investigated SMPC self-deployable driver mechanism based on the deformation mechanism of SMPC, and designed the SMPC space deployable antenna. The laminated shell structure with two pieces of back-to-back configuration was analyzed. Finite element analysis revealed that the reasonable central angle of the laminated shell cross-section was 90°. The ends fixing structure of the SMPC hinge was given. The function and structure of the hoop truss deployable antenna were designed to meet the functional and accuracy requirements.

Structure–electronic synthesis design of deployable truss antenna

This paper deals with a kind of deployable truss antenna that consists of tetrahedral modules. The structure–electronic synthesis design method is proposed and mechanical performance and electrical performance of the antenna are researched together. The basic module and structural topology are described. The coordinate of each joint, the joint angles, the length of the struts and the pattern of the joint are formulated on the basis of the topology method. By employing these formulas, numerical models of deployed and folded configuration can be built. According to the feature of the deployable truss antenna, the numerical algorithm for computing the scattered field of the antenna is developed based on geometric optics theory. The radiation integral of reflector is discrete approximated when the projection area of triangular facet onto the caliber plane is meshed by rectangular grid. Combining these two components, the structure–electronic synthesis design method of antenna is presented. A 6-meter deployable truss antenna was designed by the corresponding design procedures. The results indicated that the structure parameter and radiation-patterns of the antenna can be designed and optimized by the synthesis design method. Additionally, a scaled model of the antenna was manufactured to illustrate its feasibility.

Asynchronous Phenomenon of the Ring Truss Deployable Antenna

The deployable structure of the ring truss have advantage properties, which can be used as an effective supporting structure of deployable antenna. The deployable experiment of ring truss antenna showed that there was asynchronous phenomenon at the course of the deployment. Dynamics theory including constraint equations and considering friction factor are built firstly. Then simulation is studied systematically for the deployment process of ring truss deployable antenna. At last, the conclusions are obtained that the friction insulted in tensile forces of the cable drive decrease and the asynchronous phenomenon in the process of the deployment. It will give some help to the design and manufacture of the ring truss antenna.

Kinematics Modeling and Driving Spring Design of Truss Structure for Deployable Truss Antenna

To design a truss structure of deployable truss antenna with 7 modules and ensure that the truss structure can be deployed successfully in space environment, kinematics equation of single module with homogeneous coordinate transformation method is built based on the structure and deployment principle of truss structure. By using dynamics software ADAMS, simulation analysis on the deployment is carried out and the driving force of single module is obtained in the ground condition. On this basis, driving spring is designed, and all the important design parameters are obtained. The analytical results show that the driving spring can meet the requirement of deployment in the ground condition. So it can be deployed in orbit (0G). This method can be taken as the theoretical basis for the design and deployment experiment of truss structure.

Kinematics Modeling and Driving Spring Design of Truss Structure for Deployable Truss Antenna

Kinematics Modeling and Driving Spring Design of Truss Structure for Deployable Truss Antenna

Research on the Natural Frequency Prediction Method for Ring Tension Truss Deployable Antenna

It is nearly impossible to carry out prototype experiments of large deployable space antennas because of their large dimensions. To solve this problem, a performance prediction approach is proposed in this paper. The prototype’s working performance is predicted by the scale model of the large deployable antenna. Based on this method, the natural frequency of the ring tension truss deployable antenna working in space is studied. The effect of the structural parameter distortion is taken into consideration by similarity criteria, and a similarity experimental formula of structural natural frequency is obtained. Four finite element models are established to validate the correction of the prediction method. The simulation results show that it’s valid for the prediction method to analyze the prototype in space, and it can be applied to promote the design, and performance prediction of the large deployable antennas.

Deployment analysis and control of deployable space antenna

A deployable space antenna has a deployment mechanism which has high precision and reliability. The articulated mechanism is able to alter its configuration without failure from a compact to deployed shape to meet specific operational requirements. Consequently, the analysis of the dynamic characteristic of the deployment mechanism must be done at an initial design stage. In this paper, the kinematic, dynamic analysis and control methods to predict the deployment motions of the hoop truss deployable antenna are presented. First, the general model of deployment kinematic analysis is established. The model can be applied to carrying out the position, velocity and acceleration analysis of any point on the structure. Second, the dynamic model for the hoop truss deployable antenna is established based on the Lagrange method in multibody dynamic systems and using absolute generalized coordinates, which takes into consideration the dissipative force, torques of torsional springs in hinges and the pretension forces in nets. The force-controlled method is presented to control the deployment motion, and the relation between the driving force and the deployment motion is derived. The variation of the driving force is obtained according to the planned deployment motion. The deployment dynamics of the hoop truss deployable antenna is simulated, and the effects of initial velocity, damping and gravity upon deployment are summarized. Deployment dynamic analysis and control of the hoop truss deployable antenna are carried out taking into account the stiffness of torsional spring, damping in joints, gravity and the pretension forces in nets. The results of simulation experiment validated the proposed method.

Electro-magnetic Performance Research on Tetrahedron Truss Antenna

提出了一种构架单元式的展开桁架天线. 对构架式可展天线的电性能进行了研究, 以确定较优的设计参数和结构方案. 针对可展 反射面形态的具体特点, 基于几何光学原理, 推导了可展天线远场的电场强度公式, 将口径面划分成矩形网格, 用数值方法对远场场强进行积分, 得到天线反射面 的方向图. 进而编制相应程序, 用于分析不同设计参数的构架式天线反射面的电性能. 该方法直接将结构变形与天线电性能相联系, 避免了通过均方根换算带来的额外 误差, 使得设计更准确. 此方法同样适用于标准抛物面或者任何已知缺陷反射面的辐射场计算.

Analysis of Dynamic Characteristics of Space Deployable Antenna Based on ANSYS

Analysis of dynamic characteristics is one of the important parts of structure analysis for space deployable antenna. In order to study the dynamic characteristics of truss structure for space deployable truss antenna, according to the structure composition, the finite element model of truss structure is built by using ANSYS software, and the modal analysis is carried out by finite element method, then the natural frequencies and the features of vibration modes are obtained. It is emphatically analyzed that the influence of structure parameters such as chords, vertical beams, diagonal beams and crossing cables on the first natural frequency, and the change curves of natural frequency are given. The results can provide the theoretical basis for the antenna’s structural optimization design and dynamic modification.

Deployment Experiment of Deployable Truss Antenna

Experimental study of a proportional deployable truss antenna model is presented.The experimental scheme was discussed.The motioning acceleration of measuring nodes was gathered during movement.Then the experimental result was compared with the analytical result using the program based on the Moore-Penrose generalized inverse matrix theory.The reliability of the generalized inverse matrix theory to analyze this kind of structures was proved.

Design Method of Truss Structure with the Same Size Module for Deployable Truss Antenna

Design Method of Truss Structure with the Same Size Module for Deployable Truss Antenna

Deployment dynamic analysis of deployable antennas considering thermal effect

Dynamic analysis of flexible multibody systems is complex. Several successful methods have been demonstrated. However, few works discussed the dynamic performance of the flexible multibody under different temperatures. This paper uses the absolute nodal coordinate formulation to analyze the flexible body dynamics of deployment structures under different temperatures to simulate space environments. The dynamic equations of finite element in temperature field are developed. Then a computer-aided simulation of flexible multibody systems in temperature field is implemented. A general four-bar mechanism under different temperatures as a simulation example is demonstrated, and the deployment characteristics of a special four-bar mechanism as a basic module of the hoop truss deployable antenna is analyzed under different temperatures in order to evaluate the dynamic performance of the deployable antenna in space environments. The simulation results indicate the influence factors of deployment dynamic characteristics include the structural form, material properties, geometric parameters and deployment planning in ambient and thermal/vacuum environments.

Theoretical Analysis of Surface Error for Deployable Truss Antenna

摘要: 针对可展桁架天线杆件多和转动铰多的特点, 研究杆件加工公差和转动铰间隙对天线反射面精度和重复展开精度的影响. 根据杆件加工公差和转动铰间隙发生的随机性, 建立相应的随机数据模型和Monte-Carlo随机有限元模型, 计算杆件加工公差和转动铰间隙所引起的天线反射面精度误差. 研究表明, 间隙所引起的反射面精度误差远大于杆件公差所引起的误差, 并且天线重复展开精度差值不宜忽视. 关键词: 展开桁架天线 / 公差 / 间隙 / Monte-Carlo法 / 随机有限元 / 形面精度误差

Thermal Analysis of Deployable Truss Antenna in Orbit

Using conduction-radiation theory,considering the orbit of the antenna,temperature fields of a deployable truss parabolic antenna in orbit can be calculated at different local time.Using Visual Fortran,a finite element program based on the theory above is built,and temperature fields of antennas in different orbits can be calculated at different local time.The result is useful to thermal displacement analysis and thermal control design.

Deployment Dynamic Analysis of Circular Truss Deployable Antenna With Friction

结合一种周边桁架式可展天线的模型制作,介绍了该类天线的总体布局、展开收纳机理和设计要点;然后提出了切实有效的数学算法,有效地构造了约束方程及其Jacobi矩阵,实时地模拟了结构收纳过程的约束条件,采用广义逆矩阵的方法分析了周边可展桁架运动过程;研究了摩擦这一非线性因素在其展开过程中的作用机理,建立其展开动力学模型,实现了考虑摩擦的周边桁架式可展天线结构展开动力学分析.编制了仿真程序进行算例分析,验证了分析方法的有效性.