JPH01122800A - Expansion antenna - Google Patents

Abstract

PURPOSE: To provide a high collection ratio and proper rigidity after development by arranging a plurality of pairs of extension masts consisting of a primary series of a plurality of members, extendable parabolically toward the same direction, in a developing antenna mounted in a satellite. CONSTITUTION: For developing a developing antenna in a storage condition, actuators 15 installed to the respective corner parts of a central hub 0 constructed of polygonal plate type conductive plate are driven, and a driving pulley 16 is rotated so as to rotate a developing synchronous pulley 8a on a hinge 7a. Because of this rotation, the adjacent synchronous pulley 8c is turned via a synchronous cable 9a. Subsequently, synchronous pulleys 8e, 8f are turned in the similar way, and extension mass including mast members 6a-6d are developed parabolically substantially, so that a mesh folded between the mast members 6a-6d is developed simultaneously, and then, development of the antenna is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a deployable antenna mounted on, for example, an artificial satellite.

[Conventional technology]

In recent years, as the capabilities of artificial satellite launchers such as the Space Shuttle and Ariane rocket have improved, the use of outer space in the communications field has been increasing. Under these circumstances, research and development is being actively conducted in various countries to increase the diameter of satellite antennas, which will enable the expansion of the number of users by downsizing ground-side receiving stations, as this will be an essential element for future satellite communications. Requirements for a large-diameter antenna for use on a satellite include a high storage rate due to space constraints on the launch vehicle, weight reduction to reduce launch costs, rigidity after the antenna is deployed, precision of the antenna mirror surface, and stability. .

There are various types of products that are being researched to meet these requirements.

Figures 7 and 8 are named hoop columns by Harris Co., Ltd., and published in the American academic journal [Large Space Ant].
Enna Systems Technology J
1 is a diagram illustrating a conventional deployable antenna disclosed in NAS A CP 236B (1984). FIG. 7 is a diagram showing the stored shape, FIG. 8 is a diagram showing the state in the middle of deployment, and FIG. 9 is a diagram showing the shape after deployment. (2) is - the above hoop (
The column (3), which is an axially expandable member located at the center of 2), is stretched inside the hoop, and 1! A conductive and flexible mesh (4) that serves as a wave reflecting surface has one end attached to the hoop +11 and the other end to the tip of the column (2), and is a hoop control that is stretched when deployed. The cable (5) has one end attached to the mesh (3) and the other end to the tip of the column (2), and is a surface that is stretched so that the mesh (3) becomes a paraboloid of revolution when expanded. It is a control cable.

The operation of the hoop/column type deployable antenna configured as described above is as follows. In other words, at the time of launch, as shown in Figure 1, the 7-p (1) and column (2)
It is folded 9 times and stored in a small size.

At a predetermined position or time on the orbit, as shown in Figures 8 and 9, the antenna expands by extending the hoop (1) and column (2), and the mesh (3) A mirror surface of the antenna is formed by being pulled by the control cable (5).

[Problem that the invention seeks to solve]

In addition to the above-mentioned hoop/column type deployable antenna, conventionally proposed deployable antennas include lap rib type, tension truss type, umbrella type, etc., but the hoop/column type deployable antenna has the above configuration. This has the drawback that the rigidity of the rotating eye with the column as its axis basically depends only on the tension balance of the hoop control couple, and therefore the rigidity of one rotation υ becomes a very low value. . A radially flexible rib is placed on the back side of the antenna mirror surface.

The wrap rib type, which has a structure in which the ribs are wrapped and stored around a central drum, has the same drawback. - On the other hand, it is possible to provide sufficient rigidity after deployment.

The tension truss type has a support truss with a complicated structure on the back side of the antenna mirror surface, so it has many parts, making it difficult to assemble and adjust, and it is technically difficult to develop a truss structure with high storage efficiency. . Additionally, there is an umbrella type method that can solve both of these drawbacks at the same time.

This type basically has the same structure as an umbrella, so its diameter after unfolding is twice the height when folded, making it suitable for storage space for large launch vehicles such as Ashi, Space Shuttle, Ariane Rocket, etc. Even if taken into consideration, it cannot be applied to large diameter deployable antennas such as 30m class and 50m class.

This invention was made to solve these problems, and it is possible to maintain appropriate rigidity after deployment, has a small number of parts, and is relatively easy to assemble and adjust.
It has storage efficiency that can be applied to large-diameter deployable antennas such as 50m class and 50m class antennas.

Furthermore, the present invention provides a large-diameter deployable antenna that has an unprecedented feature of being able to form a parabolic surface with a variable focus within a certain range.

[Means for Solving the Problems] The deployable antenna according to the present invention includes a polygonal flat central hub, and hinges at both ends that have a degree of freedom of rotation in a direction perpendicular to the longitudinal direction except for the free end. the central A plurality of extendable masts are attached near the apexes of the polygon of the hub in a radial manner with respect to the center of the central hub, and a pulley is attached to the central hub near the extendable mast attachment portion and is located on the zero rotation axis. Attach the provided actuator, a wire that connects the pulley on the actuator and the pulley on the hinge of the extension mast attachment part, and a conductive flexible membrane that is attached between the extension masts and is stretched during extension. It is something that

[Effect]

In this invention, when the length between the hinges of all the members and the diameter of all the pulleys are the same, the extension movement of all the members is synchronized in the same rotational direction, and The angle is always kept constant. That is,
The angle θn formed by the n-th member counted from the fixed end and the plane normal to the axis of the fixed end member in the initial state is n times the angle θ1 formed by the fixed end member and the above plane. Because of the property that the slope of the tangent to a parabola is proportional to the distance from the origin, the mast always forms an approximately parabolic shape at a deployment angle greater than a certain angle. Therefore, in a deployable antenna using this extendable mast as a support structure, the extendable mast is efficiently stored from a parabolic shape to a spiral shape or a helical shape, thereby increasing the storage efficiency of the deployable antenna.

By giving appropriate rigidity to the mast member, appropriate rigidity is given to the antenna after deployment, and by changing the mast deployment angle within a certain range, the focal point of the paraboloid of the antenna mirror surface can be adjusted. It can be made variable.

〔Example〕

FIG. 1 shows an embodiment of the deployable antenna according to the present invention in its stored state, FIG. 2 shows it in the middle of being deployed, and FIG. 3 shows it in its deployed state. In the figure, (3) is a mesh that forms the mirror surface of the antenna, (6) is a mast member that becomes the rib end of the antenna, (7) is a hinge that connects the mast member (6), and αG is a polygonal flat conductive plate. The figure shows a central hub that is connected to the mast member (6) through the hinge (7) near the apex of the polygon.

Figures 4 to 6 are diagrams showing details of the vicinity of the mast member (6) in Figure 1, with Figure 4 showing the stored state, Figure 5 showing it in the middle of extension, and Figure 6 showing it in the extended state. This is what is shown. In FIG. 4, (8) is a deployment synchronization boot IJ + mounted on the hinge (7) so as to have the same axis as the rotation axis of the hinge (7), (91 is the two adjacent Deployment synchronization pulley (deployment synchronization cable stretched like a raccoon between 81, α9 is the actuator mounted on the central hub (l), αe is the drive pulley installed on the rotation axis of the actuator, αη is stretched between the drive pulley αe, the deployment synchronization pulley (8) on the hinge (7) connecting the central hub a1 and the mast member (6), and transfers the force of the actuator α9 to the deployment synchronization pulley (8). ). In Fig. 6, αυ is the adjacent mast member (6).
Alternatively, the angle φn (n=0.1, . . . 4) formed by the central hub αG and the mast member (6) α2 is a reference plane including each vertex of the central hub αG.

α3 is the angle θn (n=1.2.=4) that each mast member (6) makes with the reference plane α2, and Q41 is the central hub αG when the hinge (7) is projected onto the reference plane α2. The distance Xn (n=1...4) from the attachment point of the mast member (6) is shown.

The deployment operation of the deployable antenna configured as described above will be described below. The deployable antenna in the retracted shape is driven by the actuator αS, and the drive pulley (le) rotates, and the drive cable tiG connects the central hub a1 and the mast member (→deployment synchronization boot I on the hinge (7a) of the coupling part).
Rotate J-(8a). The expansion synchronization pulley above (
The rotation of 8a) connects the adjacent deployment synchronization pulley (8c) with the deployment synchronization cable (strung between the deployment synchronization pulleys).
9a) Rotate by the same angle. All the deployment synchronization pulleys (8) rotate by the same mechanism as the rotation angle of the drive pulley αe.

For convenience of explanation, the mast member (6) and hinge (7) will be described below.
), Deployment synchronization pulley (8), Deployment synchronization cable (9)
A mast with multiple structures is called an extension mast.

In the process of this unfolding movement, the mast members (6a) to (
6d) Length and deployment synchronization pulleys (8a) to (8h)
Assuming that all are the same, the length X n (14a) ~ (1
Within the range of expansion angles where 4d) can be considered linear with respect to n, the angle φn (11a) ~ (11d), the angle θn (13a) ~ (15d), and the length Xn (14
The following +1+ formula holds between a) and (14d),
The extending mast has an approximately parabolic shape.

θn=nX(180'-φn) 0eXn (
11 In an embodiment of the present invention, the above-mentioned extendable mast is used as a support structure on the back surface of the antenna mirror.

When stored, the mesh (3) is attached to the mast members (6a) to (6f).
) is folded and stored so as to be rolled up, and when the extendable mast is extended by the actuators (15a) to (15f), it is expanded, and the above-mentioned extendable mast takes an approximately parabolic shape. Forms a paraboloid, that is, a parabolic surface. The focus of this parabolic surface can be changed arbitrarily by changing the unfolding angle of the drive pulley ae.

〔Effect of the invention〕

As described above, according to the present invention, in a one-dimensional continuous extension mast of υ, in which a plurality of members are one-dimensionally continuous, the expansion motion of all the members is synchronized in the same direction, thereby changing the shape from a spiral or spiral shape to a parabolic or linear shape. By using a simple structure that extends into a shape as a supporting structure member of the deployable antenna, we have achieved both a high storage rate and appropriate laterality after deployment, and also a large-diameter deployable antenna with a parabolic surface with variable focus. can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a state in which the antenna according to the present invention is housed. FIG. 2 is a diagram showing the state during the development, and FIG. 3 is a diagram showing the state after the development. Figure 4 is a diagram of the retracted state of the extension mast, Figure 5 is a diagram of its state in the middle of extension, Figure 6 is a diagram of its state after extension, and
The figure shows a state in which a conventional antenna is stored, FIG. 8 shows a state in the middle of deployment, and FIG. 1 shows a state after deployment. In the figure, (l) is a hoop, (2) is a column, (3)
is mesh, <4) ha hoop control cable, t
5>Hasurf S control cable, (611d
: Mast member, (7) is hinge, (8) is deployment synchronization pulley, (9) is deployment synchronization cable, αG is central hub, α9 is adjacent mast member and central hub α1
The angle φn (n=1 to 4), (13 is the reference plane, and α is the angle θn (n=1 to 4) that each mast member makes with the reference plane α2.
4). I is the length Xn (n-1 ~ 4)
, α9 is the actuator, αe is the drive pulley, α
D indicates a drive cable. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A polygonal flat central hub, a plurality of mast members having hinges at both ends that have a degree of freedom of rotation in a direction orthogonal to the longitudinal direction except for the free end, and connected in series via the hinges. , a pulley arranged on the rotation axis of the hinge, and a wire connecting two adjacent pulleys, and a wire radially relative to the center of the central hub near the apex of the polygon of the central hub. a plurality of extendable masts attached to the extendable mast; an actuator that is attached to the central hub near the extendable mast attachment portion and includes a pulley on a rotating shaft; a pulley on the actuator and a hinge of the extendable mast attachment portion; A deployable antenna comprising a wire that connects the pulley to the extendable mast, and a conductive flexible membrane that is attached between the extendable masts and stretched when extended.