The present invention relates to a segmented structure.
This segmented structure comprises at least two panels connected together and intended for deployment in space.
Although not exclusively, the present invention applies more particularly to a segmented structure forming part of a telecommunication satellite antenna reflector, in particular to a large antenna reflector, functioning in high frequency bands. The size of the reflector is inversely proportional to the frequency (at constant gain). Such an antenna reflector generally comprises a rigid structure (referred to as the shell) provided with a reflective surface and reinforcement means at the rear of this surface, which participate in the holding of the shell and in the connection to the satellite.
The large size of the shell of such a reflector poses problems of space requirement when a satellite provided with such a reflector is sent into space by means of a space launcher.
Thus, for rigid reflectors having diameters of several meters, a segmented structure is provided, provided with a plurality of panels, in particular a structure with three panels comprising a middle panel and two end panels.
This segmented structure also comprises a deployment device for each end panel, which is able to bring the end panel, relative to the main panel:
In such a segmented structure, each end panel can therefore adopt a storage position for transport in the space launcher and a deployed position when the satellite is in space.
Through the document EP-1 043 802, a segmented structure is known, comprising various panel-deployment means. In a particular embodiment, the deployment means comprise, in addition to a pivoting arm, a cable. This cable is a single cable that solely implements a step of the deployment phase.
The present invention relates to a segmented structure, in particular for a satellite antenna reflector, comprising at least two panels and a deployment device making it possible to carry out in space effective and advantageous deployment of these two panels.
According to the invention, said segmented structure of the type comprising:
Thus, by virtue of the invention, the secondary panel of the segmented structure may be deployed effectively and advantageously in space, from the storage position to the deployed position, as specified below.
Moreover, in a preferred embodiment, said segmented structure comprises removable means for holding the secondary panel on the main panel, said holding means being controllable and making it possible to release the secondary panel from the main panel when they are controlled, such a release releasing the movement between said secondary panel and said main panel.
Advantageously, said strip, of the technically “tape-measure” type, has at least one of the following features:
It should be noted that the document EP-1 043 802 does not disclose the use of a particular strip that makes it possible to implement main deployment steps, namely a “tape measure” that has simultaneously all the aforementioned characteristics.
Moreover, advantageously:
Moreover, in a particular embodiment, each deployment device is configured so as to achieve the simultaneous deployment of the secondary panel and of at least one intermediate panel that are such that said intermediate panel is arranged between the secondary panel and the main panel, superimposed in the storage position and in lateral contact in the deployed position, and the intermediate panel is connected to the strip so as to be able to slide along said strip. Preferably, said strip passes at least partly through the structure of said intermediate panel. In a particular embodiment, the segmented structure comprises a plurality of intermediate panels between the main panel and a secondary panel.
Moreover, in a preferred embodiment, the segmented structure comprises:
The present invention also relates to:
The present invention also relates to a method for deploying a segmented structure as aforementioned.
According to the invention, this method comprises successive steps consisting, during deployment from the storage position to the deployed position, of:
a) releasing the movement of the secondary panel with respect to the main panel, this release allowing automatic unwinding of the prestressed strip so as to bring the secondary panel from a superimposed position to a position substantially in the same mid-plane as the main panel, said strip self-locking when it is completely unwound; and
b) reeling up the strip, by means of the reel device, so as to bring the secondary panel towards the main panel until the respective contact faces thereof are substantially in contact, in particular so that end guidance can be implemented.
Advantageously, the pivoting method comprises a supplementary step consisting of effecting end guidance for achieving the deployed position.
The figures of the accompanying drawings will give a clear understanding as to how the invention can be implemented. In these figures, identical references designate similar elements.
The segmented structure 1, illustrating the invention and depicted schematically in
More precisely, the present invention relates to a segmented structure 1 of the type comprising:
This deployment device 5 is suitable for bringing the corresponding secondary panel, for example the secondary panel 3, into one or other of the following two positions, relative to the main panel 2:
In the description of the present invention:
In the preferred embodiment, depicted in
According to the invention, each of the deployment devices 5 of the segmented structure 1 comprises:
To do this, according to the invention, each strip 6 is fixed by a first of the ends thereof to the secondary panel 3, at a so-called contact face 3C thereof (which comes into contact with a so-called contact face 2C of the main panel 20 in the deployed position P2). In addition, the strip 6 is connected to the main panel 2 at the contact face 20 thereof.
Furthermore, according to the invention, each strip 6:
The segmented structure 1 therefore comprises one or more reel devices 7, in the vicinity of the contact edge 2C between the middle main panel 2 and the movable secondary panel 3, 4 when it is deployed. In the storage position P1 (
The embodiment depicted in particular in
The segmented structure 1 moreover comprises means (not shown) for holding the secondary panel 3, 4 on the main panel 2 that are distributed around each deployable secondary panel and are of the separable (or removable) type. These holding means are controllable and make it possible to release the secondary panel 3, 4 from the main panel 2 when they are controlled (via a normal deployment instruction), such release allowing the movement between the corresponding secondary panel 3, 4 and the main panel 2 and allowing the strip or strips 6 to come into action.
Such a deployment device 5 makes it possible to achieve effective and advantageous deployment of the secondary panel 3, 4, with which it is associated, from the storage position P1 (
The order of magnitude of the thickness of the strip 6 is a few tenths of a millimeter, so as to have the necessary flexibility for holding in the wound position (in the “Z” shape). The strip 6 has, in cross section, a curved shape that is such that, when the strip 6 unwinds, itself-lochs in the straight position (a “ratchet” phenomenon or effect) like a “tape measure”. The form of the strip 6 is such that, for this “ratchet” effect to occur, the strip 6 is folded in one direction or in the other (symmetrical shape and action). In a particular embodiment, the strip 6 has, as a symmetrically shaped cross section:
The strip 6 is provided with special regions (hinge regions 8A, 8B) having significantly lower bending stiffness, for example over a few centimeters, in order to localise folding regions of the strip 6 (virtual pivot connection), so that the deployment kinematics are reproducible and predictable. This effect can be obtained by a local narrowing of the curved shape and/or by a minor modification to the thickness of the strip 6. In particular, the deployment and rewinding can thus be achieved many times on the ground, using a gravity compensation system.
The stiffness of the strip 6 is determined so that the deployment kinematics are suited to the inertias of the secondary panels 3 and 4, and cause a minimum of parasitic vibratory movements.
For the strip 6 (spring), a high modulus of resilience, satisfactory strength and good resistance to alternating bending are sought. It is possible for example to use a 45Si7 steel alloy (leaf spring) or a “piano wire” type spring. It is also possible to use Elinvar (steel with 33% nickel, 12% chromium, 1.2% manganese) in order to obtain a Young's modulus independent of the temperature.
Moreover, in a particular embodiment, in which the strip 6 also serves to transmit a signal (in electrical form) or electrical power, it is possible to use a cuproberyllium (Cu—Be) alloy. Its resilient limit is as high as a 1000 MPa, with very good resistance, and very good thermal and electrical conductivity.
It is also possible to use composite materials, in particular based on glass fibres or carbon fibres, which have advantageous strength and mass characteristics.
In addition to the choice of material, the performance of the strip 6 is also dependent on a surface treatment applied to said strip 6. This treatment may for example be prestressing blasting on a metal material.
In the folded position, the deployable secondary panels 3 and 4 are stacked by points distributed at the periphery of the main panel 2. Release of the stacking points allows automatic deployment of the secondary panels 3 and 4 through the spring effect of the strips 6.
In a particular embodiment, the segmented structure 1 comprises auxiliary means (not shown) suitable for generating thrust on the secondary panel 3, 4 in order to move it away from the main panel 2, so as to assist the deployment thereof. Preferably, to do this, springs are incorporated in the panel stacking device, in order to generate a pulse (thrust) at the start of the deployment of the deployable secondary panels 3 and 4.
Moreover, in order to limit the influence of the temperature on the stiffness of the strip or strips 6, each strip 6 is provided with flexible thermal shields at least at said flexible hinge regions 8A, 8B.
Moreover, in a particular embodiment, the strips 6, the natural frequency of which is very low (very slender flexible structure), are secured to the structure of the middle main panel 2 by means of aramid fibres or other similar systems. These fibres are cut at the same time as the stacking points (or just a short time before) by a hot wire at the moment of deployment.
The present invention has numerous advantages, and in particular:
The reel device 7 is provided with an electric motor (not shown) arranged in the structure of the main panel 2, which rotates a reeling spindle 10 (depicted in
The segmented structure 1 also comprises a damping device 11 suitable for damping any shocks liable to be generated at least at the moment of locking of the strip 6 in the unwound position.
In a particular embodiment depicted in
Once the strip 6 is unwound in the straight position (
If necessary, it is possible to provide synchronisation between the two (or even more than two) reel devices 7 of the deployment device 5, in particular by a flexible mechanical connection or by homokinetic constant velocity joints (of the tripod or Rzeppa type). It is also possible to envisage a single offset motor, intended for the various reel devices 7 of the deployment device 5.
The segmented structure 1 also comprises means configured so as to effect end guidance making it possible to achieve the deployed position P2. In a particular embodiment, these means comprise a normal cone/counter-cone system.
The deployment devices 5 of the segmented structure 1, associated with the various secondary panels 3 and 4 of this segmented structure 1, therefore make it possible to achieve deployment of the segmented structure 1 from a fully stowed position (in which all the secondary panels 3 and 4 are in a storage position P1, as depicted in
The deployment device 5 also comprises means that are not shown (for example a central unit) for controlling in particular the electric motors of the reel devices 7 and/or generating a deployment instruction.
The functioning of the deployment device 5, for deploying one 3 of said secondary panels 3, 4, from the storage position P1 in
a) the movement of the secondary panel 3 with respect to the main panel 2 is released, from the storage position P1 in
b) the two strips 6 are reeled, by means of the associated reel devices 7, as illustrated by an intermediate position PE in
The deployment method also comprises an additional step consisting of effecting normal end guidance in order to achieve the deployed position P2, by bringing the secondary panel 3 in contact with the main panel 2 in the required final position, as illustrated in
To do this, the segmented structure 1 comprises means (not shown) for allowing a precise final positioning between the secondary panel 3 and the main panel 2, as well as means for locking the panel or panels in the deployed position P2.
The same deployment method is used for the secondary panel 4 so as finally to obtain a fully deployed position of the segmented structure 1, as depicted in
Of course, the device 5 can also bring the segmented structure 1 from the deployed position P2 to the storage position P1, if this were to prove necessary, for example for a validation operation, by performing the aforementioned operations in the reverse order (b, a), with each operation performed in the reverse direction.
Moreover, in a particular embodiment, depicted schematically in
In this case, the deployment device 5 is configured so as to effect the simultaneous deployment of the secondary panel 3, 4 and at least one intermediate panel 23, 24. This intermediate panel 23, 24 is arranged between the secondary panel 3, 4 and the main panel 2, superimposed in the storage position P1, as depicted in
In this case, in a particular embodiment, the strip 6 passes at least partly through the structure of the intermediate panel 23, 24, as depicted by the dashes in
In the example in
In
The intermediate panels 23, 24 are floatingly mounted on the deployment strip or strips 6. In order to ensure absence of collision of the panels with each other and controlled and reproducible kinematics, the segmented structure 1 comprises a system 27 for blocking in translation the intermediate panels 23, 24 with respect to the strip or strips 6. This blocking system 27 is automatically retracted in a reliable manner during the operation of reeling the strips 6.
In a particular embodiment depicted in
Moreover, in order to activate the stacking systems 25 offset on the intermediate panels, the strips 6 may be used to directly conduct the necessary electrical energy without the addition of dedicated cabling, which has advantages in terms of simplicity and robustness.
In a variant depicted in
In this case, the left-hand panels (with respect to the plane L) are released before or after the right-hand panels in order not to cause a collision.
In the example in
The segmented structure 1 as described above, comprising in particular a deployment device 5, makes it possible to achieve a deployment that is simple and reliable by design, very light, and very compact in terms of payload, and has a low production and integration cost. In addition, it is possible to deploy a plurality of superimposed panels in order to deploy large systems 1 in a plurality of directions.
Number | Date | Country | Kind |
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13 02971 | Dec 2013 | FR | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/FR2014/000267 | 12/10/2014 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2015/092160 | 6/25/2015 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
4811034 | Kaminskas | Mar 1989 | A |
Number | Date | Country |
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1 043 802 | Oct 2000 | EP |
2 777 118 | Oct 1999 | FR |
S58 101507 | Jun 1983 | JP |
2009153454 | Dec 2009 | WO |
Entry |
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International Search Report dated Mar. 30, 2015, issued in corresponding International Application No. PCT/FR2014/000267, filed Dec. 10, 2014, 8 pages. |
Written Opinion dated Mar. 30, 2015, issued in corresponding International Application No. PCT/FR2014/000267, filed Dec. 10, 2014, 6 pages. |
International Preliminary Report on Patentability dated Jun. 21, 2016, issued in corresponding International Application No. PCT/FR2014/000267, filed Dec. 10, 2014, 1 page. |
Written Opinion of the International Searching Authority dated Mar. 30, 2015, issued in corresponding International Application No. PCT/FR2014/000267, filed Dec. 10, 2014, 8 pages. |
Number | Date | Country | |
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20160315393 A1 | Oct 2016 | US |