JP2008236500A - Expansion type antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an expansion type antenna reflection mirror for space devices that is expansible with high reliability. <P>SOLUTION: An expansion type antenna comprises: a metal mesh 7 constituting a radio wave reflection plane of the antenna; a shape holding cable 2 holding a shape of the metal mesh 7; a network cable including a back cable 3 and a tie cable 4; a plurality of expansion ribs 1 and expansion hinges 5. The expansion ribs 1 and the network cable are separately arranged without being connected to each other and when expanding expansion masts 12, they are expanded independently, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a deployable antenna mounted on a space device such as an artificial satellite or a spacecraft.

  As antenna reflectors mounted in space equipment, larger objects are required with the expansion of space use such as satellite communication and astronomical observation. However, since the launcher storage space at launch is limited, the antenna reflector is housed in a rocket fairing having a diameter of about 2 m to 4 m with the antenna reflector folded down, and the antenna is deployed on the orbit after launch.

  As an example of such an antenna reflector, there is conventionally known a deployable reflector in which a tension is applied to a foldable mesh mirror surface that forms a polyhedral structure with a triangle as one element in the deployed state. ing. In this deployable antenna reflector, a cable having high rigidity is used for the inner surface cable, and a cable having low rigidity is used for the outer peripheral surface cable (see, for example, Patent Document 1).

JP 2006-870578 A

  In addition, by connecting the mirror side cable and the rear cable with a tie cable to form a network cable, holding the mirror mesh that constitutes the antenna mirror surface with the mirror side cable, and holding the anti-leakage film with the rear cable, 2. Description of the Related Art A deployable antenna reflecting mirror that prevents cable entanglement by forming a closed space sandwiched between membrane surfaces is known (see, for example, Patent Document 2).

JP-A-7-142924

  When the antenna is deployed in orbit after the launch of the satellite, the failure of the deployment mechanism hinders the antenna deployment operation. For example, the deployable antenna is composed of a deploying rib, a network cable, and a mirror mesh, and the deploying operation of the antenna is stopped when the mirror mesh, the network cable, and the deploying rib are entangled. In Patent Document 2, a closed space sandwiched between two membrane surfaces is formed so that hard objects such as network cable nodes and deployment rib hinges are not entangled with the cable, and the deployment reliability of the antenna is improved. Can be improved.

  However, since the back cable must also form an accurate network, it is necessary to prevent the shape of the cable from collapsing due to contact with the development rib. For this reason, the rear cable has to be arranged at a position away from the development rib by a predetermined distance or more. At this time, the entire rear cable needs to have a shape close to a flat surface with a small amount of curvature so that the distance between the mirror-side cable and the rear cable does not become too large, thereby increasing the tension applied to the cable. Thus, there has been a problem that the deployment mechanism for applying tension to the cable is also enlarged, and the weight of the entire antenna is increased due to an increase in electric power and an increase in the size of the motor.

  The present invention has been made to solve the above-described problems, and an object thereof is to obtain a deployable antenna reflector that can be deployed with high reliability.

  The deployable antenna reflector according to the present invention has a metal mesh that constitutes the radio wave reflecting surface of the antenna, a shape holding cable that holds the shape of the metal mesh, a back cable, and a tie cable that connects the shape holding cable and the back cable. A network cable, a plurality of deployment ribs and a deployment hinge that deploys the deployment ribs, deploys the metal mesh and the network cable from a folded state, and holds the metal mesh and the network cable after deployment. A plurality of deployment masts and a tendon cable connecting between the deployment masts, and the deployment rib and the network cable are arranged separately without being connected to each other, and are independently provided when the deployment mast is deployed. It is something to deploy.

Further, the development mast is stored so that adjacent development ribs are alternately folded,
Each of the development ribs is composed of a frame member coupled in a rectangular ring shape, and is arranged on a diagonal line in the frame member of the rectangular ring shape for each of the development ribs connecting the base of the development mast to the tip. A rope that connects the two apexes alternately and continuously, and a winding device that winds the rope to unfold the deployment rib may be provided.

  According to the present invention, by separating the network cable and the deployment rib, it is possible to prevent the mirror mesh, the network cable, and the deployment rib from being entangled during deployment.

  Furthermore, since the back cable supporting the cable can be greatly curved and formed on an arc, the tension of the back cable can be reduced. For this reason, it is possible to reduce the weight of the extension mechanism that pushes out the development rib.

Embodiment 1 FIG.
The deployable antenna according to the present invention has a configuration in which the deployable mast and the cable are separated so that the deployable rib and the cable are not entangled, and the rear cable is pushed up from the lower end of the deployable rib. Thus, the rear cable is configured so as to be able to be largely bent while avoiding the development rib.

The first embodiment according to the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing an example of a deployable antenna reflector according to Embodiment 1 of the present invention. FIG. 1A shows a side view of one developing rib, FIG. 1B shows a top view, and FIG. 1C shows an AA ′ cross-sectional view of FIG. . In FIG. 1C, the mirror mesh is removed, and an arrangement relationship of only the network cable and the deployment rib is shown. This deployable antenna reflector is mounted on the launcher in a retracted state, and is launched on a track and then deployed to a large diameter. In FIG. 1, only the state after deployment is shown.

  In the figure, the deployable antenna reflector includes a rectangular deployable rib 1, a shape holding cable 2 disposed on the reflector surface side, a back cable 3 disposed on the opposite side of the reflector surface, and a tie cable 4. The deployment hinge 5, the mirror mesh 7, the tendon cable 8, and the cable support portion (end frame) 10 are configured. The development rib 1 constitutes a truss structure by assembling rod-shaped members into a square shape and further providing rod-shaped members for connecting square diagonal lines. The deployment ribs 1 are connected to each other by a deployment hinge 5 so as to be rotatable. The plurality of deployment ribs 1 are connected by a deployment hinge 5 to form a deployment mast 20. The deployable antenna reflector is attached to the satellite body (center hub) 6 of the artificial satellite through the deployable rib 1 at the base of the deployable mast 20.

  A cable support 10 is attached to the deployment rib 1 at the tip of the deployment mast 20. Six to eight deployment masts 20 are arranged radially around the satellite body 6. One end of the shape retaining cable 2 and the rear cable 3 is connected to the cable support 10. The satellite body 6 is connected to the other end portions of the shape retaining cable 2 and the rear cable 3.

  The shape-preserving cable 2 and the back cable 3 are discretely connected by a plurality of tie cables 4 and are bound at node points. The tie cables 4 are arranged so as to be substantially parallel with a predetermined interval. The shape-preserving cable 2, the back cable 3, and the tie cable 4 are bundled in a mesh to form a cable network. Node points of the mirror mesh 7 are discretely bound to the shape retaining cable 2. The shape retaining cable 2 is appropriately bundled along the mirror surface shape formed by the mirror surface mesh 7 so as to retain the mirror surface shape of the mirror surface mesh 7, and is suitable for the rear cable 3 and the tie cable 4 connecting the same. By applying tension, the curved shape is maintained. The back cable 3 has a shape curved in the opposite direction to the shape retaining cable 2, and the back cable 3 and the shape retaining cable 2 approach each other around the center portion of the deployment mast 20.

  At this time, the cable is held around the central portion of the deployment mast 20 so that the lower end portion of the rear cable 3 is positioned on the mirror mesh 7 side above the lower end portion of the deployment rib 1. In particular, in the example of FIG. 1, the lower end portion of the back cable 3 is positioned above the lower end portion of the development rib 1. In this way, since the tension is applied by connecting the shape retaining cable 2 and the back cable 3 with the tie cable 4, the tie cable 4 can be pulled in the vertical direction to which the tension is applied. In addition, the tendon cable 8 is connected between the development masts in a hexagonal shape so as to surround the satellite body 6 as a center. When the number of deployment masts is 8, the tendon cable 8 connects the deployment masts in an octagonal shape so as to surround the satellite body 6 as a center.

  The unfolded deployable antenna reflector has the cable 2, the mirror mesh 7 and the unfolding rib 1 folded in a small size and stored. That is, the cable 2 and the mirror surface mesh 7 are condensed and arranged in a narrow space. After launching the satellite, when it is put into orbit from this condensed state, a holding / releasing portion (not shown) releases the holding of the developing rib 1.

  At this time, a predetermined tension is applied between the cables by using an extension mechanism (not shown) to open the adjacent deployment ribs 1 until the relative angles of 180 degrees with each other. As the extension mechanism, for example, a mechanism in which a ball screw that sequentially moves the developing rib 1 straight by rotation of a motor is attached to the base of the developing mast 12 may be used. In accordance with the rotation of the ball screw, the development rib 1 is sequentially sent out (extruded) in the direction of the tip of the development mast from the development rib 1 at the tip. As a result, in the deployable antenna reflector, the unfolding rib 1 gradually unfolds on the track as if the folding screen is opened from the end.

However, if the shape retaining cable 2 and the mirror mesh 7 come into contact with the development rib 1 during development and the contact portion is caught by the development rib 1, the cable becomes entangled and cannot be developed.
Therefore, in the first embodiment, as shown in the cross-sectional view of FIG. 1 (c), the development rib 1 and the network cable are separated from each other by separating the development rib 1 and the network cable. Can be.

  Further, as shown in the top view of FIG. 1B, the network cable 20 is partially configured in units of triangular blocks, and the partial cable network 20 is arranged in a circular shape with a slight gap. Then, the partial cable networks 20 are connected by the connection cable 13. Thereby, the partial network cables 20 are separated from each other, and the deployment mast 12 is arranged in the gap between the adjacent partial network cables 20 so that the network cable and the deployment mast 12 are not entangled with each other. be able to. In the example of FIG. 1B, six partial cable networks 20 are configured.

  Further, since the network cable can be stored separately from the development rib, the folding storage method can be determined independently compared to the case where the development rib and the network cable are stored together.

  FIG. 2 is described as a comparative example of the first embodiment. FIG. 2 (a) shows a side view thereof, and FIG. 2 (b) shows a triangular prism-shaped development without separating the development rib 1 and the network cable. The example which has arrange | positioned the navel network so that a rib may be wrapped is shown.

  In the example of FIG. 2B, the strength of the deployment mast can be increased by configuring the deployment mast with triangular prism-shaped deployment ribs. However, in this case, since the triangular prism-shaped development ribs are included in the network cable, it is difficult to completely separate them during storage. For this reason, at the time of expansion | deployment, a network cable, a mirror surface mesh, and an expansion | deployment rib may be entangled.

  On the other hand, as shown in FIG. 2C, an example in which the triangular prism-shaped development rib and the navel network are separated can be considered. However, since the tie cable needs to be inclined so as to avoid the triangular prism-shaped deployment rib, it is difficult to maintain the tension in the inclined tie cable. Further, since the opening of the rear cable located on the bottom surface side in the triangular cross section of the triangular prism-shaped development rib becomes large, the in-plane tension of the deployment antenna cannot be maintained, and the mirror surface accuracy is deteriorated.

  However, since the deployable antenna according to this embodiment separates the network cable from the deployable rib, it is possible to suppress the entanglement between such a cable, mirror mesh, and deployable rib.

  As described above, the deployable antenna according to the first embodiment connects the metal mesh 7 constituting the radio wave reflection surface of the antenna, the shape holding cable 2 that holds the shape of the metal mesh 7, the rear cable 3, and both. It is composed of a network cable having a tie cable 4, a plurality of deployment ribs 1 and a deployment hinge 5, and is deployed from a state in which the metal mesh 7 and the network cable are folded. After deployment, the metal mesh 7 and the network cable are held. A plurality of deployment masts 12 and a tendon cable 8 for connecting the deployment masts. The deployment rib 1 and the network cable are arranged separately without being connected to each other, and are deployed independently when the deployment mast 12 is deployed. Further, the rear cable 2 is bent in the direction opposite to the shape retaining cable 2 so that a part of the rear cable 3 is disposed on the shape retaining cable 2 side above the lower end of the development rib 1. The network cable is divided into a plurality of partial network cables 20 and the deployment mast is arranged in a gap provided between the partial network cables. Further, the development mast 12 is stored so that the adjacent development ribs 1 are alternately folded.

  By comprising in this way, the tangle of the mirror surface mesh 7, the network cable, and the expansion | deployment rib 1 can be prevented at the time of expansion | deployment.

  Furthermore, since the back cable 2 supporting the cable can be greatly curved to form an arc, the tension of the back cable 2 can be reduced. For this reason, it is possible to reduce the weight of the extension mechanism that pushes out the development rib 1.

Embodiment 2. FIG.
The second embodiment according to the present invention will be described below with reference to the drawings.
FIG. 3 is a view showing an example of the deployable antenna reflector according to the second embodiment of the present invention. FIG. 3 shows a state where the development mast 12 is being developed. In the figure, the unfolding mast 12 is constituted by a folding unfolding rib 30. Other configurations are the same as those of the first embodiment. The foldable unfolding rib 30 is constituted by a bar-like member having spring properties.

  As a result, by releasing the restraint of the folding type developing rib 30 from the folded state, the folding type developing rib 30 is instantly opened. That is, the folding-type development rib 30 is developed like a surprise box of a toy.

  In this embodiment, the development rib is constituted by the folding type development rib 30, and the network cable is separated from the development rib as in the first embodiment. For this reason, compared with the case where the deployment rib and the network cable are stored together, the folding storage method can be determined independently.

  Further, by storing and deploying the development rib in a structure in which a spring-like rod-like member is bent and deployed, the deployment hinge can be significantly reduced compared to the first embodiment, and the weight can be reduced. Will improve. Furthermore, the extension mechanism required for deployment with the reduction in weight can also be reduced in size and weight.

Embodiment 3 FIG.
The third embodiment according to the present invention will be described below with reference to the drawings.
FIG. 4 is a diagram showing an example of the deployable antenna reflector according to the third embodiment of the present invention, and shows a state during the deployment. In the drawing, the development rope 41 is connected to two locations on the diagonal line of the development rib 40 and is taken up by the rope winding device 42.

  In the first embodiment, the antenna is deployed using the extension mechanism, but in the present embodiment, the deployment rib 40 is deployed using the rope 41. The development rib 40 is configured by connecting upper and lower horizontal frame members with vertical frame members and connecting the respective frame members in a rectangular ring shape. A rope 41 is slidably connected to two apexes arranged diagonally in the rectangular ring-shaped frame member. At this time, the ropes 41 are stretched in a zigzag manner so that the ropes 41 are line-symmetric with respect to the vertical frame members. That is, the rope 41 is connected so that two diagonal vertices in the rectangular ring-shaped frame member are alternately and continuously connected to each of the development ribs 40 connecting the base to the tip of the development mast. ing.

  By winding the rope 41 with the rope winding device 42, the deployment rib 40 is pulled by the tension of the rope 41 and deployed. That is, when the rope 41 provided on the diagonal line is pulled by the rope winding device 42, the rope 41 is pulled on both sides of the vertical frame member, and the deployment rib 40 is extended according to the pulling force. The rope 41 can be configured to be lightweight, and the rope winding device 42 can also be configured by providing a simple motor. With this configuration, the entire deployable antenna can be reduced in weight.

  In addition, you may provide the winding spring which gives the expansion | deployment torque to the rotating shaft which rotatably supports the expansion | deployment rib 1 as the expansion | deployment hinge 5. As shown in FIG. As a result, an initial rotation angle of, for example, about 30 ° can be given to the development rib 40, so that when the rope 41 is pulled, the development rib 40 can be reliably opened.

It is a figure for demonstrating the structure of the expandable antenna by Embodiment 1 of this invention. 6 is a diagram for explaining a comparative example of the deployable antenna according to Embodiment 1. FIG. It is a figure for demonstrating the structure of the expandable antenna by Embodiment 2 of this invention. It is a figure for demonstrating the structure of the expandable antenna by Embodiment 3 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Deployment rib, 2 Shape retention cable, 3 Back cable, 4 Tie cable, 5 Deployment hinge, 6 Satellite main body (center hub), 7 Mirror surface mesh, 8 Tendon cable, 9 Triangular prism-shaped deployment rib, 10 Cable support part, 12 Deployment Mast, 20 partial network cable, 30 folded unfolding rib, 41 unfolding rope, 42 rope take-up device.

Claims (5)

A metal mesh constituting the radio wave reflection surface of the antenna;
A shape retaining cable for retaining the shape of the metal mesh, a rear cable, and a network cable having a tie cable for connecting the shape retaining cable and the rear cable;
A plurality of unfolding ribs and unfolding hinges for unfolding the unfolding ribs, unfolding the metal mesh and the network cable from a folded state, and after unfolding, a plurality of unfolding masts for holding the metal mesh and the network cable; ,
A tendon cable for connecting the development masts;
With
The deployable antenna is characterized in that the deployment rib and the network cable are arranged separately without being connected to each other, and are deployed independently when the deployment mast is deployed. 2. The back cable is bent in the direction opposite to the shape retaining cable so that a part of the back cable is disposed on the shape retaining cable side above the lower end of the development rib. The deployable antenna described. 2. The deployable antenna according to claim 1, wherein the network cable is divided into a plurality of partial network cables and the deployable mast is disposed in a gap provided between the partial network cables. 3. The deployable antenna according to claim 1, wherein the deployable mast is housed so that adjacent deployable ribs are alternately folded. Each of the deployment ribs is composed of a frame member joined in a rectangular ring shape,
Furthermore, for each deployment rib that connects between the base of the deployment mast to the tip, a rope that connects two consecutive vertices arranged diagonally in the rectangular ring-shaped frame member, and
A rope winder that winds the rope to unfold the unfolded rib;
The deployable antenna according to claim 3, further comprising:

Images