CN108417991B - Synchronously-deployable ring beam for annular truss type reflector - Google Patents

Abstract

The invention provides a synchronously deployable ring beam for a ring-shaped truss reflector, which belongs to the technical field of satellite antennas. , two horizontal rods, one oblique rod and two identical synchronous deployment mechanisms; each synchronous deployment mechanism includes a sliding hinge, a synchronous rope and three pulleys that are matched together; the sliding hinge is located on a vertical rod, and the sliding hinge and The T-shaped hinge located on the other longitudinal rod is respectively connected with the two ends of a horizontal rod through the rotating pair; the first pulley and the second pulley are fixed on the sliding hinge and both are tangent to the synchronizing rope, and the third pulley is fixed On the T-shaped hinge of the other longitudinal rod; one end of the synchronizing rope is fixed on the longitudinal rod fixed joint of one longitudinal rod, and the other end goes around the three pulleys in turn and is fixedly connected with the sliding hinge on the other longitudinal rod. The invention has the characteristics of simple structure, good synchronization, and constant synchronization rope length and tension value.

Description

A synchronously deployable ring beam for a ring truss reflector

technical field

The invention belongs to the technical field of satellite antennas, and relates to a synchronously deployable ring beam for a ring truss reflector.

Background technique

In recent years, with the increasing demand for communication and deep space exploration, the diameter of satellite antennas has gradually increased. However, due to the limitation of rocket launch space, it is necessary to develop a satellite antenna that can be deployed. The annular truss-type deployable (understood as both deployable and retractable) reflector Astromesh (US Patent No. 5680145) is one of the typical successful representatives of deployable satellite antennas, which has the advantages of light weight, high stiffness, large shrinkage ratio and easy The advantages of unfolding. The reflector Astromesh is composed of a deployable ring beam and a mesh surface supported by the ring beam, wherein the ring beam can realize the transition of the annular reflector from a retracted state to an expanded state (for now, after the annular reflector is fully expanded , will remain in this state). Specifically, the ring beam is a periodic structure distributed along the ring direction, which is formed by connecting the same quadrilateral elements. The quadrilateral elements can be collapsed and expanded. See Figure 1, in which Figure (a) shows the intermediate process configuration of the expansion of the ring beam. Schematic diagram, Figure (b) is a schematic diagram of the fully expanded configuration of the ring beam. According to the difference in the way of folding, the annular reflector can be divided into a first-generation configuration (abbreviated as AM1) and a second-generation configuration (abbreviated as AM2). The notable feature of AM2 is that it adopts a sliding hinge to slide along the longitudinal rod to reduce the retracted height. Under the same focal-to-diameter ratio, the retracted height of AM2 is 40% lower than that of AM1. Considering the limited space for rocket transportation, the height of AM2 is smaller when it is folded, so AM2 is suitable for realizing a larger diameter annular reflector.

For the deployable ring beam of the second-generation annular reflector, see (c) and (d) in Figure 1, each quadrilateral element in the ring beam includes two parallel and equal-length longitudinal rods (3 and 9). ), two equal-length transverse rods (6 and 11) and a diagonal rod 12, and a longitudinal rod fixing joint (1 and 7) and a T-shaped hinge (4 and 10) are respectively fixed at both ends of each longitudinal rod, Moreover, the longitudinal rod fixed joints and the T-shaped hinges on the two longitudinal rods (3 and 9) are arranged diagonally, and the two ends of the inclined rod 12 are respectively connected with a T-shaped hinge through a rotating pair. Each basic quadrilateral element of the ring beam is rectangular in the fully expanded state. The key to the expansion of the ring beam is that each quadrilateral element should be expanded synchronously, that is, to ensure that the motion of each basic quadrilateral element is consistent. To this end, each basic quadrilateral unit in the existing ring beam is also provided with two synchronous deployment mechanisms, and each synchronous deployment mechanism ensures that the adjacent sliding hinges slide the same on the longitudinal rod through a set of synchronous ropes bypassing the pulley. the distance. For one of the synchronous deployment mechanisms (located at the lower left), it specifically includes a matching sliding hinge 2, a synchronous rope 13 and two pulleys (5 and 14), and the other synchronous deployment mechanism (located at the upper right) Similar to it; each sliding hinge is located on one longitudinal rod, and can slide up and down along the corresponding longitudinal rod; each sliding hinge and the T-shaped hinge located on the other longitudinal rod are respectively connected with the two ends of the corresponding transverse rod through a rotating pair; The two pulleys are respectively fixed on the T-shaped hinges and the sliding hinges fixed with different longitudinal rods; the lower synchronizing rope 13 bypasses the two pulleys 5 and 14 at the two inflection points respectively, and one end of the lower synchronizing rope 13 is fixed on the left sliding hinge 2. The upper and other ends are fixed on the right longitudinal rod fixing joint 7. The arrangement and winding method of the upper synchronizing rope 16 is similar to that of the lower synchronizing rope 13 . During the movement of the basic quadrilateral unit from retracting to unfolding, the wrapping angle of each pulley (the central angle corresponding to the contact arc length between the synchronizing rope and the pulley) will decrease from about 180 degrees to about 90 degrees, considering the size of the pulleys It cannot be ignored that the length of the entire synchronizing rope will change during the unwinding process. If the synchronizing rope is tensioned in the retracted state, it will gradually loosen during the unfolding process, thus greatly weakening the synchronizing effect. Therefore, the motion consistency of each quadrilateral element cannot be guaranteed, and even the ring beam cannot be fully unfolded in severe cases.

SUMMARY OF THE INVENTION

In order to overcome the shortcomings of the prior art, the present invention provides a synchronously deployable ring beam for a ring-shaped truss reflector, which can realize the synchronous deployment of each basic quadrilateral element of the ring beam, and has the characteristics of simple form and easy realization. .

For realizing the purpose of the present invention, adopt following technical scheme:

A synchronously deployable ring beam for a ring-shaped truss reflector is formed by connecting a plurality of identical basic quadrilateral units distributed along the circumferential direction, and each basic quadrilateral unit includes two longitudinal rods, two transverse rods, A diagonal rod and two identical synchronous deployment mechanisms, a longitudinal rod fixed joint and a T-shaped hinge are respectively fixed at both ends of each longitudinal rod, and the longitudinal rod fixed joint and T-shaped hinge on the two longitudinal rods are diagonal. Arrangement, the two ends of the inclined rod are respectively connected with a T-shaped hinge through a rotating pair; two adjacent basic quadrilateral units share a longitudinal rod, and the two basic quadrilateral units are symmetrically arranged about the longitudinal rod;

Each synchronous deployment mechanism includes a matching sliding hinge, a synchronizing rope with a fixed rope length, and three pulleys; wherein, the sliding hinge is located on a longitudinal rod and slides up and down along the longitudinal rod, and the sliding The hinge and the T-shaped hinge located on the other longitudinal rod are respectively connected with the two ends of a horizontal rod through a rotating pair; the first pulley and the second pulley are fixed on the sliding hinge and both are tangent to the synchronizing rope, The third pulley is fixed on the T-shaped hinge of the other vertical rod, one end of the synchronization rope is fixed on the vertical rod fixed joint of one vertical rod, and the other end goes around the three pulleys in turn and slides on the other vertical rod hinged connection;

The setting of the three pulleys also needs to meet the following requirements: the radius of the second pulley and the third pulley are equal; the circle centers of the second pulley and the third pulley respectively coincide with the rotation centers of both ends of a crossbar; The horizontal distance between the center of the pulley and the corresponding crossbar is closer than that of the first pulley, and at the same time, the vertical distance between the center of the second pulley and the fixed joint of the vertical rod on the corresponding vertical rod is closer than that of the first pulley, and the first pulley is closer to the corresponding vertical rod. The direction of the synchronization rope between the fixed joints of the longitudinal rod on the rod and the direction of the synchronization rope between the first pulley and the second pulley are both parallel to the longitudinal rod, and the direction of the synchronization rope between the sliding hinges on the third pulley to the other longitudinal rod is the same as that of the other longitudinal rod. a longitudinal bar parallel;

The two synchronous deployment mechanisms are arranged centrally symmetrically with respect to the geometric centroid of the basic quadrilateral unit.

The beneficial effects of the present invention are:

The present invention proposes a synchronously deployable ring beam for an annular truss reflector. By improving the synchronous deployment mechanism, it is ensured that the length of the synchronizing rope does not change with the configuration of the basic quadrilateral unit during the deployment of the annular reflector. Each sliding hinge in the beam produces the same displacement, thus ensuring the synchronization of the motion of the basic quadrilateral elements. The invention has the characteristics of simple structure, good synchronization, and constant synchronizing rope length and tension value.

Description of drawings

Figure 1 is a schematic diagram of the existing Astromesh second-generation configuration (AM2) ring beam deployment, Figure (a) is a schematic diagram of the intermediate process configuration of the ring beam deployment, Figure (b) is a fully deployed configuration schematic diagram of the ring beam, Figure (c) ) is a schematic structural diagram of the basic quadrilateral unit in Figure (a), and Figure (d) is a schematic structural diagram of the basic quadrilateral unit in Figure (b).

FIG. 2 is a schematic structural diagram of the basic quadrilateral unit of the ring beam of the present invention in a folded state.

FIG. 3 is a schematic structural diagram of the basic quadrilateral unit of the ring beam of the present invention in a fully expanded state.

FIG. 4 is the sliding distance of the left and right sliding hinges in this embodiment.

FIG. 5 is the change in length of the upper and lower synchronizing ropes of this embodiment.

FIG. 6 is a graph of the difference between the slip distance and the input distance in this embodiment.

Detailed ways

The synchronously deployable ring beam of the annular truss reflector proposed by the present invention is further described as follows with reference to the accompanying drawings and embodiments:

A synchronously deployable ring beam for a ring-shaped truss reflector proposed by the present invention is formed by connecting a plurality of basic quadrilateral units with the same structure distributed along the circumferential direction, and each basic quadrilateral unit includes two parallel and equal lengths A longitudinal rod, two equal-length transverse rods and a diagonal rod are respectively fixed at both ends of each longitudinal rod with a longitudinal rod fixed joint and a T-shaped hinge, and the longitudinal rod fixed joint and T-shaped hinge on the two longitudinal rods are respectively fixed. The hinges are arranged diagonally, and the two ends of the inclined rod are respectively connected with a T-shaped hinge through a rotating pair; two adjacent basic quadrilateral units share a longitudinal rod, and the two basic quadrilateral units are symmetrically arranged about the longitudinal rod; each basic quadrilateral The units also respectively include two identical synchronous deployment mechanisms, and each synchronous deployment mechanism includes a matching sliding hinge, a synchronous rope with a fixed rope length, and three pulleys; the sliding hinge is located on a vertical rod, and It can slide up and down along the vertical rod; the sliding hinge and the T-shaped hinge located on the other vertical rod are respectively connected with the two ends of a horizontal rod through a rotating pair, and the first pulley and the second pulley are fixed on one vertical rod. On the sliding hinge and both are tangent to the synchronizing rope, the third pulley is fixed on the T-shaped hinge of the other longitudinal rod, one end of the synchronizing rope is fixed on the longitudinal rod fixing joint of one longitudinal rod, and the other end goes around the three longitudinal rods in turn. After one pulley is fixedly connected to the sliding hinge on the other longitudinal rod; the setting of the three pulleys must also meet the following requirements: (1) the radius of the second pulley and the third pulley are equal; (2) the second pulley and the third pulley have the same radius; The center of the circle coincides with the rotation center of the two ends of a crossbar respectively; (3) The horizontal distance between the center of the second pulley and the corresponding crossbar is closer than that of the first pulley, and at the same time the center of the second pulley is fixed with the vertical rod on the corresponding vertical rod The vertical distance of the joint is closer than that of the first pulley, and the direction of the synchronizing rope between the first pulley and a vertical rod fixed joint and the first pulley to the second pulley is parallel to the vertical rod, and the third pulley to The direction of the synchronizing rope between the sliding hinges on the other longitudinal rod is parallel to the other longitudinal rod; the two synchronous deployment mechanisms are arranged symmetrically with respect to the geometric centroid of the basic quadrilateral unit.

The ring beam of the annular truss reflector of the present invention can be expanded synchronously. During the expansion movement of the basic quadrilateral unit, the improved synchronous expansion mechanism can ensure that each segment of the synchronization rope is parallel to the corresponding transverse rod and longitudinal rod respectively; the synchronization rope goes around and slides The wrapping angle of the pulley on the hinge close to the longitudinal rod remains unchanged, and is constant at 180 degrees; the wrapping angle of the pulley on the synchronous rope around the T-shaped hinge gradually decreases with the increase of the expansion degree of the basic quadrilateral unit, but the wrapping angle of the synchronous rope around the sliding hinge increases The wrap angle of the pulley that is far away from the longitudinal bar increases gradually with the expansion of the basic quadrilateral unit. It can be proved geometrically that the sum of the above two wrap angles is always 180 degrees. Therefore, the total length of the synchronizing rope can be maintained during the expansion process. constant. When the annular truss reflector is unfolded, the sliding hinge on one side moves from the middle position of the longitudinal rod to the top of the longitudinal rod, so under the action of the synchronizing rope, the sliding hinge on the other side also moves the same distance. Considering that each basic quadrilateral unit is connected in series to form a whole ring beam, the synchronous deployment mechanism can ensure that the sliding hinges on each longitudinal rod will move the same distance, so that the deployment process of each unit can be synchronized, and the synchronizing rope The tension value remains unchanged. When the basic quadrilateral unit is in the unfolded state, the wrapping angle of the synchronizing rope on the pulley of the sliding hinge close to the cross bar (the central angle corresponding to the arc length of the contact portion) is equal to 90 degrees.

Example:

The specific structure of this embodiment is shown in FIG. 2 and FIG. 3 . Fig. 2 is the transition state (between the collapsed state and the expanded state) of a basic quadrilateral element in the deployable ring beam of the second-generation configuration of the annular truss reflector Astromesh shown in Fig. 1, and Fig. 3 is the transition state of a basic quadrilateral element. expanded state. The components of a basic quadrilateral unit include parallel and equal-length left and right longitudinal bars 3 and 9, equal-length lower cross bars 6 and upper cross bars 11, and one oblique bar 12. Both ends of the left longitudinal bar 3 are respectively fixed with The upper longitudinal rod fixing joint 1 and the lower T-shaped hinge 4, the lower longitudinal rod fixing joint 7 and the upper T-shaped hinge 10 are respectively fixed at both ends of the right longitudinal rod 9, and the longitudinal rod fixing joints on the two longitudinal rods (3 and 9) The two ends of the inclined rod 12 are respectively connected with a T-shaped hinge through a rotating pair. Each basic quadrilateral unit also includes two identical synchronous deployment mechanisms, each synchronous deployment mechanism includes a matching sliding hinge, a synchronous rope with a fixed rope length, and three pulleys, and one of the synchronous deployment mechanisms is now used. Examples are described in detail. The sliding hinge 8 is located on the right longitudinal rod, and can slide up and down along the longitudinal rod. The sliding hinge and the T-shaped hinge 4 located on the left longitudinal rod 3 are respectively connected with the two ends of the lower transverse rod 6 through a rotating pair. The pulley 15 and The pulleys 14 are fixed on the sliding hinge 8 of the right longitudinal rod 9 and both are tangent to the synchronizing rope 13 , the pulley 5 is fixed on the T-shaped hinge 4 of the right longitudinal rod 3 , and one end of the synchronizing rope 13 is fixed on the right longitudinal rod 9 On the fixed joint 7 of the vertical rod, the other end goes around the three pulleys in turn and is fixedly connected with the sliding hinge 2 on the left vertical rod 3 (specifically, the other end of the synchronization rope 13 is first parallel to the right vertical rod 9 upward, and then goes around The pulley 15 on the sliding hinge 8 then turns parallel to the right longitudinal bar 9 downward, then turns around the pulley 14 and turns parallel to the lower cross bar 6 to the left, then bypasses the pulley 5 on the T-shaped hinge 4 and turns parallel In order to ensure that the length of the synchronous rope remains unchanged during the unfolding process, the setting of the three pulleys also meets the following requirements: (1) The radius of the pulley 14 and the pulley 5 are equal, and the pulley The radius of 15 is not required to be equal to the pulleys 5 and 14; (2) the center of the pulley 14 and the pulley 5 coincide with the rotation centers of both ends of the lower cross bar 6 respectively; (3) The center of the pulley 14 is horizontal to the lower cross bar 6 The distance is closer than that of the pulley 15, and at the same time, the vertical distance between the center of the pulley 14 and the longitudinal rod fixing joint 7 on the right longitudinal rod 9 is closer than that of the pulley 15. And the direction of the synchronization rope between the pulley 15 and the longitudinal rod fixed joint 7 on the right longitudinal rod 9 and between the pulley 15 and the pulley 14 are all parallel to the right longitudinal rod 9, and the pulley 5 to the left longitudinal rod 3. The direction is parallel to the left longitudinal bar 3 . Specifically, the center of the pulley 15 is located at the upper right of the pulley 14, and the horizontal position of the pulley 15 relative to the pulley 14 should keep the synchronization rope 13 between the two pulleys parallel to the right longitudinal rod 9, and the vertical direction of the pulley 15 The position only needs to be located above the pulley 14, and the specific size is not required; the two synchronous deployment mechanisms are arranged symmetrically with respect to the geometric centroid of the basic quadrilateral unit, and the setting method of the other synchronous rope 16 is similar to that of the synchronous rope 13. It will not be repeated here. In actual work, the sliding of the sliding hinge along the longitudinal rod is realized by the drive rope controlled by the motor, but this does not guarantee that each sliding hinge slides the same distance along the longitudinal rod, so the above-mentioned synchronous deployment mechanism is required to ensure that each sliding hinge is Slide the same distance to ensure the synchronization of the basic quadrilateral elements of the ring beam. Since the synchronous rope driving mechanism and the above-mentioned synchronous deployment mechanism are independent and unrelated, the implementation scheme of the driving mechanism will not be described in detail here.

The dimensions of each component in this embodiment are as follows: the ring beam is composed of 6 basic quadrilateral units connected in the circumferential direction, the diameter of the ring beam is 2 meters when fully unfolded, the length of each transverse rod is 530.2 mm, the length of each longitudinal rod is 1384.7 mm, and the length of each pulley is 530.2 mm. The radius is 7mm; the installation distance of the two pulleys on the T-shaped hinge is 97mm; a total of 4 pulleys (for the use of two adjacent quadrilateral units) need to be installed on the sliding hinge, which can be divided into two parts according to the symmetry of the center line of the sliding hinge. The installation distance of two pulleys in the group close to each other is 69mm, and the installation distance of the other two pulleys is 97mm; the length of the two synchronizing ropes is 1970.9mm. The individual components are conventional parts.

Example validity verification:

Firstly, simulation is used to verify the effectiveness of the synchronous rope winding pulley scheme proposed by the present invention in which the rope length remains unchanged during the unfolding process. A basic quadrilateral unit is established, which is in a fully unfolded state at the initial moment, and a displacement drive is applied to the sliding hinge 2, so that it gradually slides down from the top along the left longitudinal rod 3. Under the action of the synchronizing rope, the sliding hinge 8 on the right side will slide upward, so that the basic quadrilateral unit is gradually closed. The change of the sliding distance of the sliding hinge 2 and the sliding hinge 8 with time is shown in Fig. 4, and it can be seen that the displacements of the two remain the same. After that, continue to apply displacement drive to the sliding hinge 2, so that it gradually slides upward along the left longitudinal rod 3 from the bottom end, under the action of the synchronizing rope, the sliding hinge 8 on the right slides down, so that the basic quadrilateral unit Gradually until fully expanded. The sliding distance of the two sliding hinges 2 and 8 on the longitudinal rod during the deployment process is quantitatively counted, as shown in Figure 4, it can be seen that the two sliding hinges 2 and 8 can ensure the same displacement during the entire deployment process, That is, the synchronization of the movement can be guaranteed. In addition, the changes in the lengths of the upper synchronizing rope 16 and the lower side synchronizing rope 13 during the deployment process are also counted, as shown in FIG. 5 . It can be seen that the length of the synchronization rope can remain unchanged during the unfolding process.

Afterwards, the sliding hinges are numbered from 0 to 6 in sequence. The sliding hinge No. 0 is the active displacement driving end, and the other points are passively moved under the action of the synchronizing rope. Measure the displacement of each sliding hinge Δ _i , i=1,2 ,…,5. When the movement of the sliding hinge is less than 150mm, use a vernier caliper to measure, and the measurement error is about ±1mm; when it is greater than 150mm, use a tape measure to measure, and the measurement error is about ±2mm. The active drive end makes the displacement Δ0 on the No. ₀ sliding hinge first increase from 0 to 686 mm (the ring beam retraction stage), and then decrease from 686 mm to 0 mm (the ring beam deployment phase). In order to obtain the difference between the displacement of No. 1-5 sliding hinges and the displacement of No. 0 input sliding hinge according to the measurement results, the results are shown in Figure 6. It can be seen that the largest difference occurs in the unfolded state, about 10mm, and the largest difference in the middle state of motion is about 6mm. Considering the errors of machining and assembly, it can be seen that the present invention has good synchronization in the experiment.

The above are only preferred embodiments of the present invention, and do not limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are all included in the present invention. within the scope of protection.

Claims (1)

1. A synchronously deployable ring beam for a ring-shaped truss reflector is formed by connecting a plurality of identical basic quadrilateral units distributed along the circumferential direction, and each basic quadrilateral unit includes two longitudinal rods, two horizontal rod, a diagonal rod and two identical synchronous deployment mechanisms; at both ends of each longitudinal rod, a longitudinal rod fixing joint is fixed at one end, and a T-shaped hinge is fixed at the other end, and the longitudinal rod fixing joints on the two longitudinal rods are It is arranged diagonally with the fixed joint of the longitudinal rod, and the T-shaped hinge and the T-shaped hinge are arranged diagonally; the two ends of the inclined rod are respectively connected with a T-shaped hinge through a rotating pair; the adjacent two basic quadrilateral units share a longitudinal rod, And two basic quadrilateral units are symmetrically arranged about the longitudinal rod; it is characterized in that: Each synchronous deployment mechanism respectively includes a sliding hinge, a synchronous rope with a fixed rope length, and three pulleys; wherein, the sliding hinge is located on a vertical rod, and slides up and down along the vertical rod, the sliding The hinge is connected with one end of a horizontal bar through a rotating pair, and the T-shaped hinge located on the other vertical bar is connected with the other end of the horizontal bar through a rotating pair; the first pulley and the second pulley are fixed on the sliding hinge and Both are tangent to the synchronization rope, the third pulley is fixed on the T-shaped hinge of the other longitudinal rod, one end of the synchronization rope is fixed on the longitudinal rod fixed joint of one longitudinal rod, and the other end goes around the three pulleys in turn. Afterwards, it is fixedly connected with the sliding hinge on the other longitudinal rod; The setting of the three pulleys also needs to meet the following requirements: the radius of the second pulley and the third pulley are equal; the circle centers of the second pulley and the third pulley respectively coincide with the rotation centers of both ends of a crossbar; The horizontal distance between the center of the pulley and the corresponding crossbar is closer than that of the first pulley, and at the same time, the vertical distance between the center of the second pulley and the fixed joint of the vertical rod on the corresponding vertical rod is closer than that of the first pulley, and the first pulley is closer to the corresponding vertical rod. The direction of the synchronization rope between the fixed joints of the longitudinal rod on the rod and the direction of the synchronization rope between the first pulley and the second pulley are both parallel to the longitudinal rod, and the direction of the synchronization rope between the sliding hinges on the third pulley to the other longitudinal rod is the same as that of the other longitudinal rod. a longitudinal bar parallel; The two synchronous deployment mechanisms are arranged centrally symmetrically with respect to the geometric centroid of the basic quadrilateral unit.

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