JPH01245707A - Expanded antenna structure - Google Patents

Abstract

PURPOSE:To attain small size, light weight, to improve the accuracy of mirror surface and to simplify the mirror surface adjustment by providing a polygonal expansion truss to be freely folded and expanded, an expansion truss with a couple of cable trusses connected by a tensile cable and a reflection mirror surface formed by the combination of plural mesh members of nearly triangle shape so as to form the antenna. CONSTITUTION:A controller selectively applies drive control of an actuator of each expanded truss 11 to apply expansion/contract control to an expanding member 10d thereby expanding or holding the antenna. The mesh member constituting the expansion truss 20 and the reflection mirror surface is expanded or folded. Moreover, if the shape of parabola is changed due to a cause such as an alignment error or thermal distortion in a universe environment, the shape is adjusted into a desired parabolic shape by using the controller again. Since the mirror surface accuracy is set by both the expansion trusses 10 and 20, the highly accurate mirror surface accuracy is ensured. Furthermore, since many hard points exist, the mirror surface adjustment is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a deployable antenna structure used, for example, in an antenna device for radio wave communication of several tens of GHz.

(Prior art) Recently, future space antenna devices have been developed using methods that transport component parts from the ground to outer space and assemble them.
A deployment method in which the antenna device is folded and stored on the ground and then transported to space and expanded, or a method in which each part of the antenna device is divided into several parts in advance and assembled in space are being considered. However, with either method, there are various problems in terms of assembly workability and assembly accuracy of the antenna structure, but currently it is considered effective to use a deployable antenna structure. ing.

By the way, as the antenna structure of the above-mentioned deployment method, there are known a deployment truss structure in which a polyhedral truss is combined with rigid members, and a deployment truss structure in which a cable such as a wire is used.

The former includes the deployable truss described in JP-A No. 61-98699 and NASA cp2368.213-23.
Box truss antenna described on page 3, NASA
cp2368. There are deployable tetrahedral truss antennas described on pages 237 to 250, and the latter includes NASA
Examples include a hoop force uneven antenna described in 0p-2269, pages 381 to 421, and a tension truss antenna described in IAF-87-317.

However, the above-described expanded truss structure is basically constructed by combining polyhedral elements such as tetrahedrons to form a macroscopic parabola, so the size of one element determines the mirror accuracy. So, for example, 20GHz
When forming a large device that targets high frequencies, such as a band, it is difficult to realize it unless a large number of very small elements are combined. According to this, there is a problem that it is inevitably heavy and large in size, making it difficult to transport to outer space.

In addition, the above-mentioned extension truss structure is effective in terms of assembly requirements and weight, but the so-called hard point in the structure is that the cable is supported by arranging a truss/boom that expands and contracts one-dimensionally. Therefore, since there are very few hard points, it is very troublesome to adjust the mirror surface, and the mirror surface adjustment work is very complicated.

Therefore, there is a strong need to develop a deployable antenna structure that can be applied to future space antenna devices.

<Problems to be Solved by the Invention> As detailed above, conventional deployable truss structures and extensible truss structures are large and heavy, and adjustment of mirror surface accuracy is complicated. However, due to poor workability, it was difficult to apply it to space applications.

This invention was made in view of the above circumstances, and is compact and
It is an object of the present invention to provide a deployable antenna structure that is lightweight, improves mirror surface precision, and simplifies mirror surface adjustment work.

[Structure of the Invention (Means for Solving the Problems) This invention consists of a polyhedral-shaped deployable trust that can be folded and deployed, and a pair of cable trusses that are constructed on this deployable truss via struts so that they can be freely expanded. A deployable antenna structure is constructed by comprising an extension truss connected to each other, and a reflecting mirror surface formed by combining a plurality of substantially triangular mesh members supported at three points on the extension truss.

(Function) According to the above configuration, the mirror surface precision is set by both the expansion truss and the expansion truss, and can be improved by the expansion truss without increasing the number of elements of the expansion truss. As a result, the expansion truss is supported by multiple struts and has multiple hard points at its corners, which simplifies the work of adjusting the mirror surface of the expansion truss, and allows for a compact and lightweight antenna structure. will also be realized.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a deployable antenna structure according to an embodiment of the present invention, in which numeral 10 denotes a tetrahedral deployable truss;
For example, 25 tetrahedral deployable truss bodies 11 are arranged in combination. The plurality of deployable truss bodies 11 are, for example,
As shown in FIG. 2, strut members 11a are erected at the four corners, and beam members 11 are provided at both ends of the strut members 11a.
b is installed and rotatably connected. Then, on a predetermined diagonal line between these support members 118, an extension member 11d equipped with an actuator 11c for driving deployment is installed.

Moreover, an expansion truss 20 having a cable truss structure is constructed on the expansion truss 10 with struts 22 disposed at the corners. As shown in FIG.
, :21a are connected by a tension cable 21b. On this cable truss 21a, a plurality of flexible substantially triangular mesh members 23 each forming a reflecting mirror surface called a mesh surface are supported at three points, as shown in FIG. laid down by This mesh member 23 has a triangular shape whose dimensions are appropriately set, for example, when the frequency used is high and high mirror accuracy is required, and the number of divisions is increased. As a result, the mirror surface precision can be improved.

The 25 deployable truss bodies 11 are each formed into a tetrahedron with four support members 11a and eight beam members 11b, and depending on the arrangement position in the deployable truss 10, for example, As shown in FIG. 4, extending members 10d or bending members 10e are appropriately combined on diagonals different from those shown in FIG. 2, so that they can be folded and unfolded.

In the above configuration, the deployable truss 10 in which the deployable truss bodies 11 are installed in appropriate combinations is deployed by selectively driving and controlling the actuators in each deployable truss body 11 by a control device (not shown) to control the expansion and contraction of the extension member 10d. Alternatively, folding is performed (see Fig. 2 (a>, (b)). In conjunction with this, the expansion truss 20 constructed on the expansion truss 10 and the mesh member 23 forming the reflective mirror surface.
is expanded or folded (Fig. 2(a)).

(see (b)). In the deployed state of the deployment truss 10 and the expansion truss 20, if the desired parabolic shape changes due to alignment error, thermal distortion, etc. in the space environment, the control device (not shown) The actuator 11c of the deployable truss body 11 is drive-controlled and adjusted to a desired parabolic shape. The mesh member 23 laid on the expansion truss 20 is adjusted in accordance with the adjustment of the mirror surface of the expansion truss 20.

In this way, the deployable antenna structure has a cable truss 21a on the tetrahedral-shaped deployable truss 10.

Expansion truss 20 in which 21a is connected with a tension cable 21b
was constructed, and a plurality of substantially triangular mesh members 23 were laid on this extension truss 20 to form a reflecting mirror surface. According to this, since the mirror surface accuracy is set by both the expansion truss 10 and the expansion truss 20, the expansion truss 20 can be This ensures high mirror surface accuracy. Further, according to this, when the expansion truss 20 is constructed on the plurality of expansion trusses 10, the corners are supported by the supports 22, and the number of hard points is increased compared to the conventional expansion truss structure.
Mirror surface adjustment work is easily accomplished.

In addition, in the above embodiment, the tetrahedral-shaped deployment truss body 11
Although the tetrahedral-shaped deployable truss 10 is constructed by combining 25 of these, the deployable truss is not limited to this, and it is also possible to construct the deployable truss with one polyhedral-shaped deployable truss body.

Furthermore, the present invention also provides the deployment truss 10 used in the above embodiments.
The present invention is not limited to this, and it is also possible to construct it using various polyhedral-shaped unfolding trusses that can be folded and unfolded, and similar effects can be expected. Therefore, it goes without saying that the present invention is not limited to the embodiments described above, and that various modifications can be made without departing from the spirit of the invention.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to improve the precision of the mirror surface while ensuring compactness and weight reduction, and to simplify the mirror surface adjustment work. It is possible to provide a deployable antenna structure with the following characteristics.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a deployable antenna structure according to an embodiment of the present invention, and FIGS. 2 to 4 are detailed diagrams showing a part of FIG. 1 in order to explain the details. be. 10... Deployment truss, 11... Deployment truss body, 11
a... Support member, 11b... Beam member, llc...
Actuator, 11d... Extension member, 11e...
Bending member, 20... Extension truss, 21a... Cable truss, 21b... Tension cable, 22... Support column, 23... Mesh member. Applicant's agent Patent attorney Takehiko Suzue (a) (b)

Claims (1)

[Claims] A polyhedral-shaped deployment trust that can be folded and deployed, an extension truss that is constructed by connecting a pair of cable trusses that can be extended via struts on this deployment truss with a tension cable, and a system that is supported at three points on this extension truss. A deployable antenna structure characterized by comprising a reflecting mirror surface formed by combining a plurality of substantially triangular mesh members laid down.