JPH04132402A - Expansion mesh antenna - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mesh antenna, and more particularly to an expanded mesh antenna.

[Prior Art] FIG. 7 is an explanatory diagram of a lap rib antenna, FIG. 8 is a perspective view of a radial rib antenna, and FIG. 9(a).

(b), (c), and (d) are a storage diagram of the box antenna, a flat unfolded state diagram, a fully developed state diagram, a partially enlarged view,
Figure 1O is a partial diagram of the cable network of a conventional truss-type mesh antenna; Figures 11(a) and (b)
, (c) is a diagram showing the relationship between the storage angle and specific tension for each cable shown in FIG. 10.

Conventionally, a deployable mesh antenna is mounted on a communication satellite or the like and is configured to be deployed in a predetermined shape at a predetermined position in outer space. Three examples based on differences in configuration will be shown below. The lap rib antenna shown in FIG. 7 is an antenna mounted on the US technology test satellite ATS-6, in which ribs 301 extend radially from the periphery of the satellite body 302, and a metal mesh 300 is placed on the concave surface formed by the ribs 301. , and a reflective mirror surface is formed. rib 30
Reference numeral 1 is an elastic material having a "0"-shaped cross section to increase strength and becomes a flat thin plate in the stored state, and is configured to be stored by being wrapped around the circumferential side of the hub 302 together with the metal mesh 300.

Figure 8 shows a radial rib antenna mounted on the US data relay satellite TDRS.A spider web is formed between each rib 312 that extends radially in multiple stages between points equidistant from the radiation center. The antenna is connected with a contour rod 311 to maintain the precision of the mirror surface of the antenna, and is stored in a closed state like an umbrella. A metal mesh 320 is provided on the concave inner surface formed by.

FIGS. 9(a), 9(b), and 9(c) are diagrams showing a deployed mesh antenna called a box truss antenna, respectively, showing the stored state and the order from planar deployment to full deployment. FIG. 9(d) shows a cable network 321 for each unit box truss 322, called a tie-back tie system, which includes a metal mesh 320 and is folded and stored like a paper balloon, as shown in FIG. 9(a). From the stored state, the metal mesh 320 sequentially extends and unfolds one by one toward the front, both sides, and upward, and when fully unfolded, the metal mesh 320 forms a mirror surface. Also, the notes in each cable network 321 were all fixed at each end of the cable.

[Problems to be Solved by the Invention] When attempting to increase the size of the conventional deployable mesh antenna described above by using a rib type (radial rib antenna, lap rib antenna) or to improve the precision of the reflective mirror surface, it is necessary to Since the central hub has a cantilevered beam shape, there are concerns about buckling due to mesh mirror tension and elastic deformation of the rib ends. This is because the buckling load Wc of a cantilever beam is given by Euler's well-known formula. Here, Wc is the buckling load, n is a constant determined by the boundary condition of the long column, E is the Young's modulus of the structure, I2 is the moment of inertia of the long column, and 1 is the length of the long column. Therefore, as the rib becomes longer, the buckling load decreases in inverse proportion to the square of the rib. Furthermore, the elastic deformation y at the end of the cantilever beam is given by assuming that a load P is applied to the end, where E is the Young's modulus of the rib, I2 is the second moment of area of the rib, and 1 is the length of the rib. ) The longer the rib, the greater the amount of deformation even if the same load is applied to the end, making it unsuitable for larger size and higher precision. A method that is considered to compensate for this drawback is to use a deployable truss as a support structure for a mesh antenna, such as the above-mentioned box truss antenna. This method attempts to suppress buckling and elastic deformation by using a more rigid deployable truss structure instead of ribs. In this case, by stretching a cable network between the discrete fixed points provided by the truss structure, it is possible to improve the mirror surface accuracy without impairing storage properties and lightweight properties. However, the box truss antenna has a structure in which all the truss members arranged along the antenna mirror surface bend, and an actuator that applies deployment force is placed at each bending point, which has the disadvantage of increasing weight. . The truss structure devised for this purpose is, for example, a deployable truss as shown in FIG. 6, which is described in Japanese Patent Application No. 63-278344 and is capable of synchronous deployment and storage with a small number of actuators. In this case as well, although it is simply thought that the cable network can improve mirror surface accuracy, it actually poses a serious problem. This means that when the truss member arranged in the in-plane direction of the antenna has a structure that does not bend, which is a feature of the synchronous deployment truss, the tension of the cable on the truss member when it is stored is higher than the tension when it is deployed. If the cable tension is high when stored, it is necessary to perform strength design in the stored state, and fine adjustments in the factory after manufacturing, such as adjusting the mirror surface shape, are usually performed in the unfolded state before storage, so it is necessary to carry out the strength design after adjustment. It is undesirable to add this load to the structure and accommodate it in terms of residual stress.

In order to quantitatively see the effect, we calculated the cable tension when the truss structure is housed using the cable and truss model shown in Figure 10. Figure 11 (a) shows the results.
Shown in (b) and (c). Here, the specific tension is the value obtained by dividing the tension at each storage position by the tension in the unfolded state. Cables 1, 2, and 3 are the Surf Ace cables that are in contact with the mirror surface, and cables 4 to 9 are the cables 1 to 3 that are in contact with the mirror surface. 109 is a standoff that supports the cable tension. The state of development in the factory is θ
= 0, and standoff 1 in the middle of Figure 10 for storage.
09 is kept vertical and its position is developed around the lower end of the other standoff 109, the cable 1.3
．． 4.5, or at least in either the positive or negative direction, the tension in the stored state exceeds the tension in the deployed state. Therefore, when the truss structure is made into a mirror support structure and a cable network method is used, all the truss members parallel to the mesh surface have conventionally been structured to bend; Since this is impossible, it is basically necessary to arrange actuators such as springs at all hinge points H, and an increase in the number of actuators has the disadvantage that it directly leads to an increase in weight.

The purpose of the present invention is to provide a mirror-like support structure in which the truss members arranged parallel to the antenna surface do not bend, so as to reduce the number of actuators as much as possible, that is, the deployable truss structure can be deployed synchronously as a result. An object of the present invention is to provide a deployable mesh antenna using a cable network.

[Means for Solving the Problems] The deployable mesh antenna of the present invention has a structure in which at least one of the truss members along the reflective mirror surface of the antenna does not bend when the antenna is deployed, when the antenna is deployed, The tie cable connecting the Surf Ace cable and the back cable between the standoffs fixed at both ends of the rigid truss member can slide freely over the cable to be connected at one end or It has sliding coupling means.

[Operation] When a truss member with an unbendable structure parallel to the antenna reflecting mirror surface is stored with one end centered and the standoff connected to the other end facing in the same direction as when deployed, Since one end of the tie cable connecting the Surf Ace cable and the back cable supported by the standoff slides freely over the cable, the truss structure of the cable changes, as shown in Figure 4. As the storage angle increases, a smaller tension is applied to each cable than in the unfolded state, making it possible to store the cables without difficulty and to store and deploy the cables including truss members with an unbendable structure that does not require an actuator. Become.

[Example] Next, an example of the present invention will be described with reference to the drawings.

Figure 1 (a), (b), (c), (d)
, (e) are respectively a perspective view of an embodiment of the deployable mesh antenna of the present invention in a deployed state, a perspective view of a cable network, a perspective view of a truss structure, an explanatory diagram around tie cables, and an explanatory diagram of use of a pulley. , Fig. 2(a), (
b) and (c) are perspective views showing the change from the retracted state to the unfolded state of the deployed mesh antenna shown in Fig. 1(a), and Fig. 3 is the perspective view shown in Fig. 1(d). FIG. 4 is a detailed view of the vicinity of the tie cable, and FIG. 5(a) is a diagram showing the relationship between the storage angle and specific tension for each cable shown in FIG. 3.

(b) is a partial perspective view of a multi-module type deployable mesh antenna to which the present invention is applied and a detailed view of the standoff joint part, and Figures 6(a), (b), and (c) are a synchronous deployable truss structure. It is a diagram showing the development sequence of.

The deployed mesh antenna shown in FIGS. 1(a) to (e) is
A metal mesh 100 that serves as a reflective mirror surface, a cable network 101 that forms the shape of the reflective mirror surface, a standoff 109 to which the cable network 101 is attached and holds its tension, and a truss structure 110 that fixes the standoff 109. and an actuator for deploying and retracting the truss structure 110. The cable network 101 includes a plurality of Surf Ace cables 103 that form the shape of a reflective mirror surface, a plurality of back cables 105 that serve as a support network for forming the shape of the Surf Ace cables 103, and connects the Surf Ace cables 103 to the back cables 105. The back cable 105 side of the tie cable 104 is slidable by pulleys 106 and 107 as shown in FIGS. 1(d) and (e). ing. There are six standoffs 109 on the periphery and one in the center, and the Surf Ace cable 103 is attached to the upper end of the standoffs 109.
is attached, a back cable 105 is attached to the lower end, and the lower end is fixed to the longitudinal truss member of the truss structure 110 with its axis parallel to it. The truss structure 110 is a truss structure that holds the vertical truss member fixing the standoff 109 in a predetermined relative position when unfolded, and each notebook is fixed when unfolded, but rotates in a predetermined storage direction. Possibly installed. Further, the hinge H shown in FIG. 1(C) is bent so as to move in the forward direction when stored, and extends linearly by an actuator (not shown) when deployed. When the actuator is deployed, all the hinges H are gradually spaced to hold it fully open, and when it is stored, the actuator gradually bends all the hinges H to fold the truss structure 110.
The entire expanded mesh antenna is brought into the state shown in FIG. 2(a).

FIG. 3 is a diagram showing the state of each cable when the truss member, which has an unbendable structure along the reflecting mirror surface, is stored. The Surf Ace cables 1, 2.3 are attached between two standoffs 109+ and 1092. , back cable 6.7, surf ace cable sides 1 and 2.3 are fixed, back cable 6.7 side is slidably connected with bootsaw, tie cables 4 and 5, and two standoffs 109+
, 1092.

In this structure, when the standoff 1o92- is translated in parallel with the rotation of the truss member 111 for storage around the lower end of the standoff 1091, each Cable 1, 2. ~7
The tension of each cable changes, and the specific tension, which is the ratio of the tension of each cable to the tension at the time of deployment, becomes as shown in FIG. 4, and both values gradually decrease as the storage angle increases from the time of deployment.

Next, the operation of this embodiment will be explained.

First, it is assembled in the expanded state at the factory, and once adjustments are completed, it is stored. When the actuator is operated on the storage side, the hinge H shown in FIG. 1(C) is bent, the truss structure 110 shifts to the state shown in FIG. 2(b), and the cable network 101 is accordingly bent. The boot saw 106.1'07 of the tie cable of the cable network part related to the truss member, which has a structure that does not deform or bend, also moves on each back cable as the standoff 109 moves in parallel, and gradually It is stored in the state shown in (a). Furthermore, during deployment, the hinge H gradually extends due to the extension of the actuator, bringing the hinge H into a straight line, and accordingly, the cable network 101 unfolds into a predetermined shape, and the pulleys 106 and 107 also stop at a predetermined position. This forms the curved surface of the antenna, and the metal mesh 1oo forms a reflective mirror surface.

FIG. 5 shows another embodiment of the deployable mesh antenna of the present invention, in which the deployable mesh antenna having the configuration of the above-described embodiment is used as a unit antenna module 200, and the antenna module 200 is connected by a coupling mechanism 201 including a standoff 109. The truss structure parts are combined to form one large antenna mirror surface as a whole. In this case as well, a sliding pulley is attached to one end of the tie cable associated with the truss member, which has an unbendable structure and is parallel to the antenna mirror surface, and all standoffs 109 are at the same height. . As a result, each antenna module 20
0 enables synchronous deployment, and mechanically speaking, if one antenna module has an actuator, the entire mirror surface can be deployed.

[Effects of the Invention] As explained above, the present invention provides an antenna with a mirror surface by using one end of the tie cable that connects the Surf Ace cable and the back cable as a connection node that freely slides on the cable. It is possible to use the majority of parallel truss members with a structure that does not bend, reducing weight, simplifying the structure, and making it more economical.Furthermore, when applied to a multi-module antenna, only one actuator is required. The coupling mechanism enables detailed adjustment between modules, and manufacturing and testing of antenna mirror surfaces can be performed in units of antenna module aperture diameters. Compared to using an integrated antenna, this method has the advantage of being more economical and more accurate.

[Brief explanation of drawings]

Figure 1 (a), (b), (c), (d)
, (e) are respectively a perspective view of an embodiment of the deployable mesh antenna of the present invention in a deployed state, a perspective view of a cable network, a perspective view of a truss structure, an explanatory diagram around a tie cable, and an explanatory diagram of use of a pulley. , Fig. 2(a), (
b) and (c) are perspective views showing the change from the retracted state to the unfolded state of the deployed mesh antenna shown in FIG. 1(a), and FIG. 3 is a perspective view of the tie shown in FIG. 1(d). A detailed view of the surroundings of the cables, Figure 4 is a diagram showing the relationship between the storage angle and specific tension for each cable shown in Figure 3, Figure 5 (a), (
b) is a partial perspective view of a multi-module type deployable mesh antenna to which the present invention is applied and a detailed view of the standoff joint, and Figures 6(a), (b), and (c) are a synchronous deployable truss structure. FIG. 7 is an explanatory diagram of a lap rib antenna, FIG. 8 is a perspective view of a radial rib antenna, and FIG. 9(a). (b), (c), and (d) are a storage diagram of the HOX antenna, a plan view of the unfolded state, a diagram of the fully developed state, and a partially enlarged view.
Figure 10 is a partial diagram of the cable network of a conventional truss-type mesh antenna, and Figures 11 (a) and (b).
, (c) is a diagram showing the relationship between the storage angle and specific tension for each cable shown in FIG. 10. 1.2,3,103--surf ace cable, 4.
5.106゜107-・tie cable, 6,7,8,9
, 105--Back cable, 100--Metal mesh, 101--Cable network, 109,1
09. ．． 109□--standoff, 110-- truss structure, 111-- truss member, 200-- antenna module, 201-- coupling mechanism. Patent applicant Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] 1. A metal mesh that constitutes the reflective mirror surface of the antenna, a plurality of surface cables that form the metal mesh into a predetermined curved surface, and a back cable that serves as a support network for forming the shape of the surface cable. , a tie cable joining the surface cable and the back cable, with the supporting end of the surface cable attached at one end and the supporting end of the back cable near the other end, so that when the antenna is deployed, the surface cable , a plurality of standoffs and a plurality of truss members to maintain tension in a cable network consisting of back cables, tie cables,
A deployable mesh antenna comprising a hinge for connecting truss members to each other and a three-dimensional deployable truss structure that fixes the plurality of standoffs and includes an actuator for storing and deploying the antenna, the reflecting mirror surface of the antenna when the antenna is deployed. At least one of the truss members along the truss member has a structure that does not bend when stored, and the surface cable and the back cable are connected between standoffs fixed to both ends of the truss member with the unbendable structure. A deployable mesh antenna characterized in that the tie cable has at one end a coupling means that freely slides or slides over the cable to which the end is to be coupled. 2. The deployable mesh antenna according to claim 1, wherein the plurality of three-dimensional deployable truss structures are coupled to each other using a coupling mechanism to form a single antenna mirror surface as a whole.