Position adjustment device with kinematic reduction

Abstract

The invention relates to a device (1) for adjusting the position of a space apparatus, comprising: an actuator (10) for generating movement along an axis (XX), a kinematic reduction stage (20) comprising an interface (201) for joining the apparatus, comprising: either two input arms (21) of the reduction stage, which are articulated to each other at a second interface for joining the actuator; or two external arms (22) which are articulated to the frame (19) and to the two input arms;or two internal arms (24) that are articulated at the joints between the external arms and the input arms and an interface arm (23) arranged transversely to the axis, the reduction stage being dimensioned such that a movement of the interface with the actuator along the axis causes a movement of the interface arm, in the same direction and with a reduced amplitude of a reduction ratio that is based on the relative lengths of the arms.;

Description

Domaine technique

[0001] This disclosure relates to a device for adjusting the position of equipment, in particular space equipment such as a telescope mirror, prism, or radio frequency antenna. Technique antérieure

[0002] To finely adjust the position of equipment, for example, to precisely orient a space telescope, it is common to use mechanisms comprising an actuator and a reduction stage for the motion generated by the actuator. The reduction stage provides a significant kinematic reduction ratio between the input motion, generated by the motor or geared motor, and the output translational motion, which is connected to the equipment and thus allows for its orientation.

[0003] For example, US patent 5,969,892 and Robert M. Warden's publication, "Cryogenic Nano-Actuator for JWST," in Proceedings of the 38th Aerospace Mechanisms Symposium, Langley Research Center, May 17-19, 2006, describe a device for adjusting the position of an instrument. This device comprises lateral walls with a tapered intermediate portion connected to a transverse wall. The tapered middle portion of this transverse wall is connected to the actuator and thus moved translationally by the actuator's motion. A second transverse wall, superimposed on the first, is connected to the upper ends of the lateral walls and is also connected to the instrument.The deformation of the transverse wall under the effect of the translation of its median portion induces a deformation of the lateral walls, and consequently a displacement of the second transverse wall, and therefore of the instrument, with a reduction ratio between the displacement of the second transverse wall and the displacement of the first transverse wall.

[0004] This equipment allows for very high resolution, defined as the instrument's translation for one step of the actuator's stepper motor, with a resolution of 7 nm per step. However, the stroke permitted by this device is limited to only 10 µm, the stroke being defined as the maximum distance traveled by the instrument at the second transverse wall.

[0005] A device for adjusting the positioning of a secondary mirror of the GAIA telescope is also known from the document by E. Urgoiti et al., "Gaia M2M Positioning Mechanism." This device includes a structure of flexible blades, one of which is driven in translation by an actuator. It is connected to an opposing blade by flexible lateral blades, thus driving the opposing blade, which is connected to the instrument, in translation. This device has a resolution of 0.2 µm and a stroke of 400 µm. A mechanism comprising a base, a moving part, and three kinematic chains interposed between the base and the moving part is also known from document FR3047614. Each chain includes an arm and a forearm connected by a joint allowing rotations about three axes, and the arm is connected to the base via a rotary actuator.

[0006] However, some applications require superior performance in terms of resolution and stroke, namely a resolution on the order of nanometers, and in any case less than 30 nm, with a stroke of several hundred microns. The devices presented above do not meet these requirements. Résumé

[0007] This disclosure improves the situation.

[0008] In particular, one purpose of this disclosure is to propose a device with a resolution of less than 30 nm and a stroke of several hundred microns.

[0009] Another purpose of this disclosure is to propose a device whose kinematic behavior is invariant with respect to temperature.

[0010] Another purpose of this disclosure is to propose a robust device capable of withstanding significant stresses, particularly for space applications in which the device is launched into space.

[0011] In this regard, a suitable positioning adjustment device for space equipment is proposed, comprising: an actuator fixed on a support frame adapted to generate a translational displacement around a central axis, and a kinematic reduction stage fixed to the frame and comprising a first interface for connection to the equipment, characterized in that the kinematic reduction stage comprises: two arms at the input of the reduction stage articulated to each other at a second junction interface with the actuator, the two arms at the input of the reduction stage forming an obtuse angle with each other, two external lateral arms articulated on one side with the frame and on the other side with the two arms at the input of the reduction stage and two internal lateral arms articulated on one side at the junctions between the external lateral arms and the arms at the input of the reduction stage and on the other side with an interface arm arranged transversely to the central axis to form the first junction interface to the equipment, each internal lateral arm forming an acute angle with one of the arms at the input of the reduction stage and with one of the external lateral arms, the kinematic reduction stage being dimensioned so that a displacement of the second junction interface with the actuator along the central axis, in one direction and with an amplitude causes a displacement of the interface arm along the central axis, in the same direction and with said amplitude reduced by a reduction ratio which is a function of the relative lengths of the arms belonging to the kinematic reduction stage.

[0012] In some embodiments, the input arms of the reduction stage and the external side arms form an M-shaped profile.

[0013] In some embodiments, the projection, on the central axis, of the joints of the external lateral arms with the frame is arranged between on the one hand the second junction interface with the actuator and on the other hand a central portion of the interface arm.

[0014] In embodiments, when considering the projection, on the central axis, of the joints of the external lateral arms with the frame, a distance taken between this projection and the second junction interface with the actuator is greater than twice a distance taken between this projection and the central portion of the interface arm.

[0015] In some embodiments, the arms, belonging to the kinematic reduction stage, which terminate in joints, are each made up of a blade whose portions at both ends have a reduced thickness.

[0016] In some embodiments, the kinematic reduction stage has a plane of symmetry, the central axis being disposed in this plane of symmetry.

[0017] In some embodiments, the internal lateral arms are inclined with respect to the central axis, so that their end connected to the interface arm is closer to the central axis than their end connected to the junction between one of the external lateral arms and one of the input arms of the reduction stage.

[0018] In some embodiments, the length of the external lateral arms is strictly less than the length of the internal lateral arms.

[0019] In some embodiments, the interface arm is further connected to the frame by a flexible blade extending perpendicularly to the interface arm and perpendicularly to the central axis.

[0020] In some embodiments, the internal side arms, the interface arm, the external side arms and the inlet arms of the reduction stage are made of a single material.

[0021] In some embodiments, the device further includes a suitable holding and releasing equipment for temporarily holding the interface arm or the external side arms.

[0022] According to another object, there is also described an assembly, comprising at least one optical or radio frequency space equipment and at least three devices according to the preceding description, for an adjustment of the position, at at least three points, of each space equipment.

[0023] In some embodiments, the space equipment is optical equipment in the form of a prism or a mirror.

[0024] In some embodiments, the space equipment is radio frequency equipment in the form of an antenna.

[0025] Advantageously, the kinematics of the device according to the present disclosure allows for high performance in terms of both resolution and stroke.

[0026] Furthermore, according to another advantage of the invention, the symmetrical configuration of the device according to the invention and the possibility of making a single-material device makes it possible to obtain temperature-invariant behavior because it allows a substantially unchanged reduction ratio to be maintained.

[0027] Advantageously, the device according to the invention exhibits high rigidity along the axis of actuation.

[0028] In some embodiments, according to yet another advantage, the lower blade of the device, which is connected to the equipment to be positioned, can also be connected to the device's support frame by a flexible lateral blade. This lateral blade allows the device to absorb forces directed perpendicular to the direction of travel and perpendicular to the direction of the blade. Such a lateral blade is useful for absorbing lateral forces during launching and thus protecting the equipment. The blade also improves transverse rigidity. Brève description des dessins

[0029] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which: Fig. 1 [ Fig. 1 ] schematically represents, in front view, a device for adjusting the positioning of equipment according to an embodiment. Fig. 2a [ Fig. 2a ] schematically represents, in front view, a translation of the equipment in a first direction. Fig. 2b [ Fig. 2b ] schematically represents, in front view, a translation of the equipment in a second direction. Fig. 3a [ Fig. 3a ] schematically represents a front view of a device for adjusting the positioning of equipment according to an embodiment in which the device includes a lateral blade connecting the lower blade to the support frame. Fig. 3b [ Fig. 3b ] schematically represents a side view of the implementation of the figure 3a . Fig. 4a [ Fig. 4a ] schematically represents an assembly comprising a wall of a piece of equipment and several devices for adjusting the position of a piece of equipment, viewed from below. Fig. 4b [ Fig. 4b [ ] schematically represents a side view of the entire figure 4a . Fig. 5a [ Fig. 5a ] schematically represents, in front view, a first configuration for maintaining the launch of a device for adjusting the positioning of equipment. Fig. 5b [ Fig. 5b ] schematically represents, in front view, a second configuration for maintaining the launch of a device for adjusting the positioning of equipment. Fig. 6 [ Fig. 6 ] shows the conventions used for the kinematic analysis of the device in front view. Description des modes de réalisation

[0030] Reference is now being made to the figure 1 which schematically represents a device 1 for adjusting the position of a piece of equipment 9, in particular a space equipment 9 such as, for example, a component of a telescope, for example a telescope mirror, a prism, or a radio frequency antenna.

[0031] One or more adjustment devices 1 can thus be used to adjust the position of a piece of equipment 9. In the case of a single device, the position of the equipment 9 can be adjusted in translation. Alternatively, with reference to figures 4a et 4b These three adjustment devices 1, representing an assembly comprising equipment 9 and devices 1 for adjusting the position of equipment 9, respectively viewed from below and from the side, can be used to adjust the position of equipment 9 at three points, thus allowing for fine adjustment of the equipment's translational position and orientation along two axes of rotation. If equipment 9 is circular or exhibits axial symmetry, the devices are advantageously evenly distributed around this axis.

[0032] Back to the figure 1 The position adjustment device 1 comprises an actuator 10, fixed on a support frame 19, the actuator 10 being adapted to generate a translational displacement about an axis XX, hereinafter referred to as the central axis. The actuator 10 may include a motor, for example a stepper motor, generating a rotational motion and a device for converting the rotational motion generated by the motor into a translational motion about the axis XX. In embodiments and according to the example shown in the figure 1 The actuator 10 may comprise a geared motor 11 consisting of a stepper motor and a planetary gearbox, driving a screw-nut system 12. The actuator has a defined input resolution, this input resolution being defined, for example, by the displacement obtained along the XX axis (in the example given above, the displacement of the nut) for one step of the stepper motor. This input resolution can be several hundred nanometers, for example, between 250 and 500 nm.

[0033] In addition, the position adjustment device 1 of a piece of equipment 9 includes a kinematic reduction stage 20, the arms of which are dimensioned and arranged, as detailed later, to have an output resolution of several tens of nanometers, for example between 20 and 50 nm for the input resolution between 250 and 500 nm.

[0034] The kinematic reduction stage 20 is also fixed to the frame and comprises, on the one hand, a first interface 201 for connection with the equipment, at which the kinematic reduction stage 20 is integral with the equipment 9, and on the other hand, a second interface 202 for connection with the actuator 10, at which point the kinematic reduction stage 20 is integral with the actuator 10. The support frame 19 is a load-bearing structure for the equipment and the positioning adjustment device 1. In the case of space equipment, this equipment may be carried on a spacecraft such as a satellite, probe, or space station, and the support frame may be a load-bearing structure, for example, a wall, of the spacecraft.

[0035] The kinematic reduction stage 20 comprises a set of articulated arms between the two junction interfaces 201,202 and the support frame 19, and whose dimensions and relative movements are configured to allow, when the second interface moves along the XX axis, that the first junction interface 201 also moves along the XX axis, in the same direction, and with a reduced amplitude of a determined reduction ratio.

[0036] The articulated arm assembly of the kinematic reduction stage 20 comprises two arms 21 at the input of the reduction stage 20. These two arms are articulated to each other at the second interface 202, which connects to the actuator 10. For example, each arm can be connected to the output of the actuator, this output being, for instance, formed by the translating nut, as in the example mentioned above. The connection of each arm 21 to the actuator output is articulated to allow articulation between the two arms. The two arms form an obtuse angle with each other, i.e., an angle between 90° and 180°. Furthermore, the two arms extend transversely to the central axis XX.

[0037] The articulated arms of the kinematic reduction stage 20 also include two external lateral arms 22, connected on one side to the frame 19 and on the other to the arms 21 at the input of the reduction stage. Thus, each external lateral arm 22 is connected on one side to the frame 19 and on the other to one end of one of the arms 21 at the input of the reduction stage, opposite the interface 202 connecting to the actuator. The external lateral arms 22 are therefore articulated on one side with the frame and on the other with the arms 21 at the input of the reduction stage.

[0038] As schematically represented in the front views of the figures 1, 2a And 2bThe input arms of the reduction stage 21 and the external lateral arms 22 form, in a neutral configuration of the kinematic reduction stage, an M-shaped profile, the midpoint of which corresponds to the interface 202 connecting to the actuator. In some embodiments, the angle formed between the external lateral arm 22 and the arm 21 to which it is connected is, for example, between 60 and 100°. The external lateral arms 22 can be inclined with respect to the central axis XX so that their ends connected to the arms 21 are closer to the central axis than their ends connected to the frame 19.

[0039] The assembly of arms of the kinematic reduction stage 20 also includes two internal lateral arms 24, articulated on one side to the junctions between the external lateral arms 22 and the arms 21 at the input of the reduction stage, and on the other side with an interface arm 23 with the equipment 9. This arm 23 extends transversely to the central axis XX and forms the first interface 201. Each internal lateral arm 24 is therefore connected at one end to the junction between an external lateral arm 22 and an arm 21 at the input of the reduction stage, and at the other end to one end of the interface arm 23, with a joint at each connection to allow relative movement between the lower internal lateral arm 24 and the other arms to which it is connected.

[0040] Each internal lateral arm 24 forms an acute angle, i.e., between 0 and 90°, with the arm 21 at the input of the reduction stage and with the external lateral arm 22 to which it is connected. In some embodiments, each internal lateral arm 24 forms an angle between 0 and 30° with the external lateral arm 22 to which it is connected, and an angle between 60 and 90° with the arm 21 at the input of the reduction stage to which it is connected. In some embodiments, the internal lateral arms 24 are inclined with respect to the central axis XX, such that their end connected to the interface arm 23 with the equipment is closer to the central axis XX than the opposite end, which is connected to an external lateral arm 22 and one of the arms 21 at the input of the reduction stage.

[0041] We have represented on the figures 2a And 2bThe possible position variations of the reduction stage 20, represented by dashed lines, relative to a neutral position represented by solid lines. The direction of movement of the junction interface with the actuator is represented by the arrow. Thus, during a movement of the second junction interface with the actuator, this movement tends to increase respectively ( figure 2a ) or reduce ( figure 2b ) the angle between the two arms 21 at the input of the reduction stage, and therefore respectively to move the external ends of the two arms 21 away from each other. As a result, the internal lateral arms 24 move apart or, respectively, towards each other, which tends to move the interface arm 23 with the equipment in the same direction of movement as the junction interface with the actuator, and according to a reduction ratio that is a function of the relative lengths of the different arms.

[0042] In some embodiments, to simplify the kinematics of device 1, device 1, and in particular the kinematic reduction stage 20, are symmetrical with respect to a plane of symmetry, the central axis XX being included in this plane of symmetry. The plane of symmetry is perpendicular to the plane of the figure 1 In this case, the two outer lateral arms 22 are of the same length, as are the two inner lateral arms 24, and the input arms 21 of the reduction stage. Also in this case, the second interface between the arms 21 and the actuator lies in the plane of symmetry and on the axis XX, midway between the two input arms 21 of the reduction stage. Finally, the interface arm 23, which forms the interface with the equipment, is also symmetrical with respect to the plane of symmetry and is therefore centered on this plane and intersected at its midpoint by the axis XX.

[0043] Regarding the relative lengths of the different arms, in some embodiments, the external lateral arms 22 have a length strictly less than that of the internal lateral arms 24. Since an internal lateral arm 24 is connected to an external lateral arm 22 at a common end, the projection, on the axis XX, of the joints between the external lateral arms and the frame 19 is located between the projection of this common end on the axis XX and the interface arm 23. In particular, the projection on the axis XX of the joints between the external lateral arms and the frame 19 can be located on the one hand between the second junction interface with the actuator 10 and the central portion of the interface arm 23.

[0044] Furthermore, and with reference to the figure 6 , considering the projection on the XX axis of the joints of the external lateral arms 22 with the frame, a distance, referenced y, between this projection and the second junction interface with the actuator is preferably greater than twice the distance referenced z between this same projection and the central portion of the interface arm 23.

[0045] In embodiments, the distance separating the ends of the arms 21 at the input of the reduction stage which are connected to the external lateral arms 22 and internal 24 is strictly greater than the length of the interface arm 23 with the equipment.

[0046] In some embodiments, the arms 21, 22, 23 and 24 are formed by blades having end portions of reduced thickness, as schematically shown in the figure 3a This allows the arms to be rigid, but the reduced-thickness end portions give the blades flexibility, enabling the joints between the arms and thus permitting the relative movements between the arms induced by the actuator's movements. The blades, for example, have a thickness between 2.5 mm and 5 mm, and their pivoting portions have a thickness between 0.5 mm and 1 mm. The blades have a specific width, for example, between 10 mm and 25 mm, as shown in the diagram. figure 3b .

[0047] In some embodiments, the internal lateral arms 24, the interface arm 23, the external lateral arms 22, and the arms 21 at the input of the reduction stage are made of a single material, meaning that each arm is formed from a single material, for example, titanium or steel. Preferably, all the arms are made of the same material, which allows all the arms to exhibit the same thermal expansion characteristics and thus prevents the kinematic behavior of the reduction stage from changing with temperature variations. In embodiments where a single common material is chosen for all the arms and the device configuration is symmetrical, the resulting kinematic reduction stage is temperature-invariant, thus maintaining a constant reduction ratio despite temperature variations.

[0048] As depicted in the [ Fig. 3a ] Or [ Fig. 3b [ ], the device 1 for adjusting the position of equipment may include a lateral blade 25, extending perpendicularly to the interface arm 23 and perpendicularly to the central axis XX. This lateral blade may be connected at one end to the interface arm 23 with the equipment, advantageously on a central portion thereof, and at the other end to the support frame 19. This lateral blade is schematically represented on the figure 3a , which represents a front view of device 1, and on the figure 3b , which represents a side view along a plane parallel to the plane of symmetry, if any, of the device. Such a lateral blade can be flexible or articulated on one side with the frame and on the other with the interface arm, so as not to impede the movement of the equipment 9 at the level of the interface arm 23. The lateral blade 25 thus allows it to absorb forces oriented in a direction normal to the plane of symmetry, represented by the double arrow of the figure 3a In particular, in the case of space equipment 9 being launched from Earth, the lateral blade allows for the resumption of forces during launch.

[0049] With reference to figures 5a et 5b In the case where the equipment 9 is space-based equipment launched from Earth, the equipment positioning adjustment device 1 may also include a holding and releasing device 30 adapted to temporarily hold, for launch, either the interface arm 23 or the external lateral arms 22 of the reduction stage 20, and to withstand the launch-induced forces on this reduction stage. figure 5a schematically represents the first configuration of the holding and releasing device 30 in which the moving part of the kinematic reduction stage, at the interface with the equipment, is rigidly held and the joints of the external lateral arms 22 vis-à-vis the frame are left free to allow the forces to be transferred. figure 5b This schematically represents the second configuration of the holding and releasing device 30, in which the interface with the kinematic reduction stage equipment is free and the joints of the external lateral arms 22 relative to the frame are rigidly held. In both cases, the kinematic reduction stage includes joints that are not rigidly held to allow for withstanding the forces during launch.

[0050] With reference to the front view of the figure 6 , we note l 1. The length of each inner lateral arm is 24. l 2 the length of each arm 21 at the input of the kinematic reduction stage, l 3 the length of each external lateral arm 22 and l 5 half the length of the interface arm 23 with the equipment.

[0051] Furthermore, it should be noted, with reference to the front view of the [ Fig. 6 ], φ 1. The angle formed between an internal lateral arm 24 and the axis XX of displacement, φ 2 the angle formed between the angle formed between an external lateral arm 24 and the axis XX of displacement, and θ the angle formed between an arm 21 at the input of the reduction stage and an axis perpendicular to the axis XX of displacement.

[0052] We also note, with reference to the front view of the [ Fig. 6 ], y the distance between the junction interface with the actuator and the projection, on the axis XX, of the joint between the external lateral arm 22 with the frame; z the distance between the junction interface with the equipment and the projection, on the axis XX, of the joint between the external lateral arm 22 with the frame; and b the distance between the joint between the external lateral arm 22 with the frame and the axis XX of movement.

[0053] Finally, with reference to the front view of the [ Fig. 6 ], we denote f the maximum stroke of the interface junction with the equipment, corresponding to the extreme displacements of actuator 10. Without going into the details of the equation, it is clear that the reduction ratio can be adjusted by adjusting the arm lengths. During a displacement of the interface with the actuator, increasing or decreasing θ results in increasing or decreasing φ 2 to cause the interface arm 23 to move in one direction or the other. Furthermore, the fact that the internal lateral arms and the interface with the equipment are positioned below the M allows for movements that meet the required precision and linear output stroke. The internal lateral arms, for example, are longer than the external lateral arms.

[0054] The resolution obtained can thus be less than 25 nm and even less than 10 nm, particularly over a portion of the actuator's input stroke, and the maximum output stroke of the device can advantageously exceed 500 µm, for example, for an input stroke between 5 mm and 20 mm. Furthermore, for a given geometric configuration, even if the reduction ratio is not constant, it remains known in advance, thus enabling the advantageous use of the invention.

[0055] The structure according to the invention includes in particular a pair of joints each connecting a link arm 21 with the actuator, an arm 22 articulated furthermore with the frame and a link arm 24 with the interface of the equipment, thus allowing a particular and advantageous kinematic compared to the prior art.

Claims

1. A position adjustment device (1) suitable for space equipment (9), comprising: - an actuator (10) fixed to a support frame (19) adapted to generate a translational displacement along a central axis (X-X) and - a kinematic reduction stage (20) fixed to the frame (19) and comprising a first connection interface (201) to the equipment, characterized in that the kinematic reduction stage (20) comprises: - two input arms (21) of the reduction stage articulated with each other at a second connection interface with the actuator, the two input arms (21) of the reduction stage forming an obtuse angle between them, - two external lateral arms (22) articulated on the one hand with the frame (19) and on the other hand with the two input arms (21) of the reduction stage and - two internal lateral arms (24) articulated on the one hand at the junctions between the external lateral arms (22) and the input arms (21) of the reduction stage and on the other hand with an interface arm (23) disposed transversely to the central axis (X-X) to form the first connection interface to the equipment, each internal lateral arm (24) forming an acute angle with one of the input arms (21) of the reduction stage and with one of the external lateral arms (22), the kinematic reduction stage being dimensioned such that a displacement of the second connection interface with the actuator along the central axis, in one direction and with a certain amplitude, causes a displacement of the interface arm (23) along the central axis, in the same direction and with said amplitude reduced by a reduction ratio which is a function of the relative lengths of the arms belonging to the kinematic reduction stage.

2. The device according to claim 1, wherein the input arms (21) of the reduction stage and the external lateral arms (22) form an M-shaped profile.

3. The device according to claim 1 or 2, wherein the projection, on the central axis, of the articulations of the external lateral arms (22) with the frame (19) is disposed between, on the one hand, the second connection interface with the actuator and, on the other hand, a central portion of the interface arm (23).

4. The device according to claim 3, wherein when considering the projection, on the central axis, of the articulations of the external lateral arms (22) with the frame (19), a distance (y) taken between this projection and the second connection interface with the actuator is greater than twice a distance (z) taken between this projection and the central portion of the interface arm (23).

5. The device according to any one of the preceding claims, wherein the arms, belonging to the kinematic reduction stage, which terminate in articulations, are each constituted by a blade, portions of which at its two ends have a reduced thickness.

6. The device according to any one of the preceding claims, wherein the kinematic reduction stage has a plane of symmetry, the central axis (X-X) being disposed in this plane of symmetry.

7. The device according to any one of the preceding claims, wherein the internal lateral arms (24) are inclined with respect to the central axis, such that their end connected to the interface arm (23) is closer to the central axis (X-X) than their end connected to the junction between one of the external lateral arms (22) and one of the input arms (21) of the reduction stage.

8. The device according to any one of the preceding claims, wherein the length of the external lateral arms (22) is strictly less than the length of the internal lateral arms (24).

9. The device according to any one of the preceding claims, wherein the interface arm (23) is furthermore connected to the frame (19) by a flexible blade (25) extending perpendicularly to the interface arm (23) and perpendicularly to the central axis.

10. The device according to any one of the preceding claims, wherein the internal lateral arms (24), the interface arm (23), the external lateral arms (22) and the input arms (21) of the reduction stage are of a single material.

11. The device according to any one of the preceding claims, for the position adjustment of space equipment (9), wherein the device further comprises holding and release equipment adapted to temporarily hold the interface arm (23) or the external lateral arms (22).

12. An assembly, comprising at least one optical or radiofrequency space equipment (9) and at least three devices (1) according to any one of the preceding claims, for a position adjustment, at at least three points, of each space equipment.

13. he assembly according to claim 12, wherein the space equipment is an optical equipment in the form of a prism or a mirror.

14. The assembly according to claim 12, wherein the space equipment is a radiofrequency equipment in the form of an antenna.

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