JPS6118599A - Stiffness holder for space missile expanding structure - 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 The present invention provides a rigidity retaining device useful for increasing the rigidity of a deployable structure such as a solar array paddle or an antenna mounted on a spacecraft such as an artificial satellite in an expanded state after deployment. Regarding.

BACKGROUND ART Deployable structures mounted on spacecraft such as artificial satellites are becoming larger as spacecraft become larger. In terms of design, such deployment structures are strongly required to be lightweight and compact when stored in the satellite body. In order to satisfy the requirements for reducing the weight of the deployable structure and making it more compact during storage, structures in which the deployable product is made of honeycomb plates and the like have been replaced by structures using film-like thin films. Hereinafter, this thin film developed structure will be referred to as a blanket. FIG. 1 shows a state in which this blanket is in the middle of being deployed.As shown in this figure, conventionally, this blanket 3 is deployed by an extension boom 2, and after deployment, the extension of the extension boom 2 is performed. The force exerts tension on the blanket 3. 1 is a spacecraft, 4 is a pallet, and 5 is a plate at the tip.

Generally, the primary vibration mode when the deployable structure shown in FIG. Also, the primary frequency is approximately 0. It is around IH2.

As described above, the attitude control system of a spacecraft that has a deployed structure with a natural frequency around fxO, IH2 has difficulty in attitude control because the natural frequency of the deployed structure and the bandwidth of the closed loop frequency characteristic of the control system are close. It has been difficult to achieve stable posture control with high accuracy. In addition, in order to improve the accuracy of attitude control, a more complicated control circuit must be incorporated.

In order to eliminate these drawbacks, the present invention increases the torsional rigidity of the entire deployable structure by routing a tensioned cable around the deployable structure in the deployed state. In addition to increasing the primary natural frequency, the tension of the cable is kept constant by inserting a compression spring in the middle of the cable against changes in cable tension due to expansion and contraction of the deployable structure due to temperature changes, The present invention provides a rigidity maintaining device for a spacecraft deployable structure that reduces changes in natural frequency.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a perspective view of a spacecraft deployable structure to which the present invention is applied, in a state in the middle of deployment, and FIG. 4 is a front view of the deployable structure after completion of deployment in the embodiment of FIG. . In addition, in FIG. 3, the blanket 3 which is a deployed structure is shown.
is in a state where it is expanded by the extension pool 2, which corresponds to FIG.

The extendable boom 2 extends from the side of the aircraft body 1.

One end of the cable 6 is fixed to a pulley 8 attached to the pallet 4, and the other end is connected to a guide 7 fixed to every other end of the fold line 3a of the blanket 3.
through the hole (shown in detail in Figure 5) and the plate 5 at the tip.
The tension adjuster 10 (shown in detail in FIG. 6) is fixed to both ends of the tension adjuster 10 fixed to the plate 5 through a pulley 9 attached to the plate 5. In the stored state, the cable 6 is wrapped tightly around the blanket 3 and the cable 6, and as the extension pool 2 extends, the blanket 3 and the cable 6 extend.
It becomes the expanded state shown in the figure. By extending the cable 6 in this way, the torsional rigidity increases with respect to the vibration mode shown in FIG. 2, so that it is possible to increase the natural frequency when it is stretched.

The tension adjuster 10 is used to keep the tension of the cable 6 as constant as possible against thermal deformation that occurs when the temperature changes due to shade, sunlight, etc. of a deployable structure in space. .

As shown in detail in FIG. 6, the tension adjuster 10 includes a tension adjuster case 13, a compression spring 11 housed in the case, and a piston rod that holds one end of the compression spring and protrudes from the case 13. 12, and the cable 6 is fixed to these case 13 and piston rod 12. Tension is applied to the cable 6 by the spring force of the compression spring 11. By setting the compression spring 11 to a spring constant such that the compression force changes little with respect to the displacement of the spring as shown in FIG.
It becomes possible to keep the tension of the pull 6 almost constant. Therefore, with such a configuration, it is possible to increase the natural frequency of the deployable structure in the expanded state, and furthermore, it is possible to keep the change in the natural frequency due to temperature changes of the deployable structure in space almost constant. It becomes possible.

As explained above, the present invention can increase the first natural frequency of the deployable structure, and the first natural frequency of the deployable structure can be increased from the bandwidth of the closed-loop frequency/wavenumber characteristics of the attitude control system of the spacecraft. moves away, making stable posture control possible.
This has the advantage of providing highly accurate attitude control.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional spacecraft deployable structure in the middle of deployment, FIG. 2 is a diagram showing vibration modes of the conventional deployable structure, and FIG. 3 is a deployment according to an embodiment of the present invention. FIG. 4 is a front view of the deployed structure of the present invention in a fully deployed state; FIG. 5 is an enlarged perspective view of the cable guide of the embodiment of the present invention; FIG. 6 is a perspective view of the structure in the middle of deployment; FIG. 7 is an enlarged longitudinal sectional view of the tension adjuster, and is a diagram showing the spring characteristics of the tension adjuster. 1...Spacecraft body, 2...Extension boom, 3.
...Blanket, 4...Pallet, 5...
Plate, 6... Cable, 7... Guide, 8, 9... Pulley, 10... Tension adjuster, 11... Compression spring, 12... Piston rod, 13... Tension adjuster case .

Claims (1)

[Claims] 1. A device for maintaining the rigidity of a deployable spacecraft structure, characterized in that a cable to which tension is applied via a spring means is routed around the periphery of the deployable spacecraft structure in the deployed state.