Design And Analysis Of An Large Hoop Truss Deployable Antenna Mechanism

In recent years, scientific researches on various aspects such as earth-observing, space communication, deep-space exploration etc, have experienced rapid development, which expands demand for the certain type of large hoop Truss deployable antenna mechanism,especially for the products with high stability in performance, light in weight, large in size. large hoop truss deployable antenna,due to its high folding ratio, high stiffness, which enable the antenna keep a stable quality and avoid radical quality fluctuation when aperture is increasing.With its numerous virtues in capabilities, hoop truss deployable antenna share more frequent application and popularity in aerospace. Therefore, it comes out a critical problem,the creation of this type hoop truss deployable antenna mechanisms with sufficient rigidity to ensure that its smooth and normal operation in space might be the initial key.This paper lay the basis of analyzing the large-sized hoop truss deployable antenna mechanism firstly, then make the summary that seven types of fundamental unrolled units that constitute the system. The next section would calculate the comprehensive evaluation index and singular or double layers hoop truss deployable antenna empirical formula,based on this, an optimal decision for the structure optimization for mechinism patterns is represented in paper. It originally puts forward that new design scheme based on the new theory referig to the large-sized antenna, which would stretch the double layers after increasing its aperture.Based on energy equivalence principle, equivalent modeling for foldable and stretchable units of this mechanism is made and equivalent continuous model with the dynamic characteristics of double-layer antenna mechanism is attained. In order to justify the correctness of applying this equivalence method, we need to compare the former result with results from the finite element calculation. Therefore, it would greatly simplify the process of analyzing the dynamic characteristics in the antenna mechanism.Next, it figures out value range of the pre-tightening force in diagonal cables, according to the force bearing of joints in double-layer hoop truss structure and then makes analysis of these two types of structures(including about cable- free antenna and antenna with cables.) before making the respective finite element models), finally, researchers have calculated natural frequency of all phrases in the experiment and their relevant modal shapes respectively, and then analyzs the necessity of approaching the diagonal cable-stayed structure with rigidity optimum. Meanwhile, the effective strategies for improving the vibration frequency in antenna mechanism are also received after making sensitivity analysis of the factors which affect the natural frequency of double-layers structure.Reviewing the former analysis and conclusion, we have processed the structural optimization design for interior layer and outer layer of the hoop truss mechanism as well as the design of the drivers and synchronization mechanism in the deployable hoop truss mechanism in details, which contributes to its function in developing and folding repeated.Furthermore, the research not only develops the two kinds of new sample machines, both contained with elastic-plastic hinge: one for the singular-layer hoop truss deployable antenna mechanism which caliber is 2m and the other for unit-structure of the double-layer hoop truss antenna but also takes experimental verification for functions and dynamic characteristics for these two sample machines.