Deployable cylindrical light shield based on shape memory polymer composite material and method

Abstract

The invention discloses an expandable cylindrical light shield based on a shape memory polymer composite material and a method, and belongs to the technical field of spaceflight expansion devices. A plurality of middle light blocking rings are arranged between the top light blocking ring and the bottom light blocking ring, the bottom end of the top light blocking ring, the top end of the bottom light blocking ring and the upper end and the lower end of each middle light blocking ring are hinged to one ends of a plurality of corresponding connecting beams respectively, and the opposite ends of every two corresponding connecting beams are fixedly connected with the corresponding ends of the corresponding elbow-shaped joints respectively. And the light shielding ring is glued with the light shielding film. The variable stiffness characteristic and the shape memory effect of the elbow-shaped joint truss and the shape memory polymer composite material elbow-shaped joint are utilized, under the action of electric heating driving excitation, the light shield mechanism in the folded state is unfolded, the light shield mechanism in the unfolded state can be folded and shaped, heating stimulation is stopped, the elbow-shaped joint stiffness is improved, and the structure is self-locked; integration of unfolding and self-locking of the light shield unfolding mechanism is achieved.

Description

Technical Field

[0001] The invention relates to a deployable cylindrical sunshade based on a shape memory polymer composite material and a method thereof, belonging to the technical field of aerospace deployment devices. Background Art

[0002] Stray light from light sources such as the sun is widely present in the space environment and has a great impact on the optical system. Installing a sunshade on the optical system can directly prevent the input of stray light. Due to the low rigidity of the sunshade and the large space it occupies, the sunshade needs to be folded and fixed during the launch phase and then unfolded during the in-orbit operation phase. However, the traditional sunshade deployment mechanism has the problems of heavy mass, low storage ratio, complex mechanical structure, large deployment impact and low mechanism reliability, which limits its widespread application in optical systems. Summary of the invention

[0003] In order to solve the problems existing in the background technology, the present invention provides a deployable cylindrical sunshade based on shape memory polymer composite material and a method.

[0004] To achieve the above object, the present invention adopts the following technical scheme: a deployable cylindrical sunshade based on a shape memory polymer composite material, comprising an elbow-shaped articulated truss and a sunshade film; the outer side of the elbow-shaped articulated truss is coated with an origami-type deployable sunshade film

[0005] The elbow-shaped joint truss includes a top light-blocking ring, a connecting beam, an elbow-shaped joint and a bottom light-blocking ring; the top light-blocking ring and the bottom light-blocking ring are horizontally arranged in parallel up and down, the bottom end of the top light-blocking ring and the top end of the bottom light-blocking ring are respectively hinged to one end of the corresponding multiple connecting beams, the multiple connecting beams on the top light-blocking ring and the multiple connecting beams on the bottom light-blocking ring are arranged one by one, and the opposite ends of every two corresponding connecting beams are respectively fixedly connected to the corresponding ends of the corresponding elbow-shaped joints; the top light-blocking ring is glued to the upper end of the shading film, and the bottom light-blocking ring is glued to the lower end of the shading film.

[0006] The elbow-shaped joint truss includes a top light-blocking ring, a connecting beam, an elbow-shaped joint, a middle light-blocking ring and a bottom light-blocking ring; the top light-blocking ring and the bottom light-blocking ring are horizontally arranged in parallel up and down, and a plurality of middle light-blocking rings are horizontally arranged in parallel up and down between the top light-blocking ring and the bottom light-blocking ring. The bottom end of the top light-blocking ring, the top end of the bottom light-blocking ring and the upper and lower ends of each middle light-blocking ring are respectively hinged to one end of the corresponding plurality of connecting beams, the plurality of connecting beams on the top light-blocking ring, the plurality of connecting beams on the bottom light-blocking ring and the plurality of connecting beams on each middle light-blocking ring are all arranged in one-to-one correspondence, and the opposite ends of every two corresponding connecting beams are respectively fixedly connected to the corresponding ends of the corresponding elbow-shaped joints; the top light-blocking ring is glued to the upper end of the light-shielding film, the bottom light-blocking ring is glued to the lower end of the light-shielding film, and each middle light-blocking ring is glued to the middle end of the light-shielding film.

[0007] The elbow joint includes two end fixings, two shape memory polymer composite sheets and two heating films; the two shape memory polymer composite sheets are arranged side by side inside and outside, and the two ends of the two shape memory polymer composite sheets are respectively fixedly connected to the corresponding end fixings, and the outer wall of each shape memory polymer composite sheet is fixed with a heating film, and each of the end fixings is respectively fixedly connected to the corresponding end of the corresponding connecting beam.

[0008] A working method of a deployable cylindrical sunshade based on a shape memory polymer composite material, the method comprising the following steps:

[0009] S1: Turn on the heating switch to energize one side of the heating film;

[0010] S2: When the temperature reaches the glass transition temperature of the shape memory polymer composite material, the stiffness of the shape memory polymer material decreases, and driven by the shape memory recovery force, the shape memory polymer composite sheet recovers from a bent state to a straight state;

[0011] S3: elbow joint driven elbow articulated truss extension;

[0012] S4: drives the shading film to unfold;

[0013] S5: Turn off the heating switch of the heating film;

[0014] S6: The surface temperature of the shape memory polymer composite material is reduced and the stiffness of the shape memory polymer material is increased, ensuring that the deployable sunshade is in a locked state.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention has a low overall weight, does not require a motor and a complex mechanical mechanism, and adopts an elbow-shaped joint truss made of a low-density shape memory polymer composite material and an ultra-thin origami unfolded shading film to solve the problem of insufficient carrying capacity of the launch vehicle;

[0017] 2. The present invention has a high volume storage ratio. When folded, the elbow joints of the elbow joint truss made of shape memory polymer composite material are folded inwards. When unfolded, no external transmission mechanism is required. The elbow joints are self-driven to unfold, thereby reducing the volume of rocket launch.

[0018] 3. The deployment of the present invention is driven by the shape memory restoring force of the elbow joint of the shape memory polymer composite material, the process is controllable, the deployment speed is slow, the impact on the system is small, and the impact on the attitude control of the spacecraft is reduced;

[0019] 4. After the invention is deployed on track, the shape memory polymer composite material is rigidified, and the structure presents high rigidity, which meets the requirements of on-track work, has a simple structure, and does not require other redundant supports;

[0020] 5. The present invention utilizes the variable stiffness characteristics and shape memory effect of the elbow joint truss and the shape memory polymer composite elbow joint. Under the action of electric heating drive stimulation, the folded state of the light shield mechanism is unfolded, and the unfolded state of the light shield mechanism can be folded and shaped. When the heating stimulation is stopped, the stiffness of the elbow joint is improved and the structure is self-locking, thereby realizing the integration of the unfolding and self-locking of the light shield unfolding mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the hood of the present invention in a folded state;

[0022] Figure 2 It is a schematic diagram of the light shield of the present invention in an unfolded state;

[0023] Figure 3 is a schematic diagram of the elbow-shaped joint truss of the present invention in a folded state;

[0024] Figure 4 is a schematic diagram of the elbow-shaped articulated truss of the present invention in an expanded state;

[0025] Figure 5 is a schematic diagram of the shading film of the present invention in a folded state;

[0026] Figure 6 is a schematic diagram of the light shielding film of the present invention in an unfolded state;

[0027] Figure 7 is a schematic diagram of the elbow joint of the present invention in a folded state;

[0028] Figure 8 It is a schematic diagram of the elbow joint of the present invention in an expanded state;

[0029] Fig. 9 is a schematic diagram of a connecting beam of the present invention;

[0030] Fig.10 is a schematic diagram of a connecting shaft of the present invention;

[0031] Fig.11 is a schematic diagram of a top light blocking ring of the present invention;

[0032] Fig.12 is a schematic diagram of the middle light blocking ring of the present invention;

[0033] Fig.13 It is a schematic diagram of the bottom light blocking ring of the present invention. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] Embodiment 1:

[0036] A deployable cylindrical sunshade based on a shape memory polymer composite material comprises an elbow-shaped articulated truss and a sunshade film 1; the outer side of the elbow-shaped articulated truss is coated with an origami-shaped unfolded sunshade film 1. The sunshade film 1 is a component for realizing the sunshade function. The elbow-shaped articulated truss is a driving component.

[0037] The elbow-shaped articulated truss comprises a top light-blocking ring 2, a connecting beam 3, an elbow-shaped joint 4 and a bottom light-blocking ring 8; the top light-blocking ring 2 and the bottom light-blocking ring 8 are arranged horizontally in parallel, the bottom end of the top light-blocking ring 2 and the top end of the bottom light-blocking ring 8 are respectively hinged to one end of the corresponding multiple connecting beams 3 through corresponding connecting shafts 6, the multiple connecting beams 3 on the top light-blocking ring 2 and the multiple connecting beams 3 on the bottom light-blocking ring 8 are arranged one by one, and are evenly distributed along the circumference of the light-blocking ring, and the connecting shafts 6 are as shown in FIG. Fig.10 As shown, the connecting shaft 6 is used to connect the light-blocking ring and the connecting beam 3, forming a rotation node between the light-blocking ring and the connecting beam 3, and is fixed to the light-blocking ring by a retaining spring to limit axial movement. The opposite ends of each two corresponding connecting beams 3 are respectively fixedly connected to the corresponding ends of the corresponding elbow joints 4; the top light-blocking ring 2 is glued to the upper end of the light-shielding film 1, and the bottom light-blocking ring 8 is glued to the lower end of the light-shielding film 1. The top light-blocking ring 2 moves to drive the light-shielding film 1 to unfold.

[0038] The elbow joint 4 includes two end fixings 4-1, two shape memory polymer composite sheets 4-2 and two heating films 4-3; the two shape memory polymer composite sheets 4-2 are arranged side by side inside and outside, and the two ends of the two shape memory polymer composite sheets 4-2 are respectively fixedly connected to the corresponding end fixings 4-1 by screws, and the outer wall of each shape memory polymer composite sheet 4-2 is fixed with a heating film 4-3, and each of the end fixings 4-1 is respectively fixedly connected to the corresponding end of the corresponding connecting beam 3 by screws.

[0039] The shape memory polymer composite sheet 4-2 is initially flat and is shaped into a folded state before being mounted on the mechanism. The folding action is achieved with the help of external force and tooling, and the unfolding action is achieved using the shape memory restoring force of the structure.

[0040] A working method of a deployable cylindrical sunshade based on a shape memory polymer composite material, the method comprising the following steps:

[0041] S1: Turn on the heating switch to energize one side (preferably the outer side) of the heating film 4-3 to heat the shape memory polymer composite sheet 4-2;

[0042] S2: When the temperature reaches the glass transition temperature of the shape memory polymer composite material, the stiffness of the shape memory polymer material decreases, and driven by the shape memory restoring force, the shape memory polymer composite sheet 4-2 recovers from the bent state to the straight state;

[0043] S3: Elbow joint 4 drives the elbow joint truss to extend;

[0044] S4: driving the light shielding film 1 to unfold;

[0045] S5: Turn off the heating switch of the heating film 4-3;

[0046] S6: The surface temperature of the shape memory polymer composite material is reduced, the stiffness of the shape memory polymer material is increased, and the deployable sunshade is locked to ensure that the deployable sunshade is in a locked state.

[0047] The above is the unfolding process of the deployable sunshade in the on-track state. When the deployable sunshade is used on the ground, it should also be folded so that it can be used next time, as follows:

[0048] Step 1: energize one side (preferably the outer side) of the heating film 4-3 to heat the shape memory polymer composite sheet 4-2;

[0049] Step 2: Since the stiffness of the shape memory polymer composite material is very small, when the temperature reaches the glass transition temperature of the shape memory polymer composite material, the elbow joint 4 is transformed into a bent shape, ie, a collapsed state, under external stimulation.

[0050] Shape memory polymer composites (SMPC) have the advantages of high strength, good damping properties, large recoverable deformation, high reliability and relatively low cost. The working principle of shape memory composites is: when the shape memory composite is heated to a temperature above the glass transition temperature T g After a certain degree, if an external force is applied to the material, the shape of the material changes. After the material cools down and the external force is removed, the changed shape is maintained. If the material is heated again to above the glass transition temperature Tg, the material automatically restores its original shape. The present invention applies it to the deployable light shielding mechanism for the preparation of the elbow joint 4.

[0051] Embodiment 2:

[0052] The difference between this embodiment and embodiment 1 is that:

[0053] The elbow-shaped joint truss includes a top light-blocking ring 2, a connecting beam 3, an elbow-shaped joint 4, a middle light-blocking ring 5 and a bottom light-blocking ring 8; the top light-blocking ring 2 and the bottom light-blocking ring 8 are horizontally arranged in parallel up and down, and a plurality of (at least one) middle light-blocking rings 5 ​​are horizontally arranged in parallel up and down between the top light-blocking ring 2 and the bottom light-blocking ring 8. The bottom end of the top light-blocking ring 2, the top end of the bottom light-blocking ring 8 and the upper and lower ends of each middle light-blocking ring 5 are respectively hinged to one end of the corresponding plurality of connecting beams 3 through corresponding connecting shafts 6. The plurality of connecting beams 3 on the top light-blocking ring 2, the plurality of connecting beams 3 on the bottom light-blocking ring 8 and the plurality of connecting beams 3 on each middle light-blocking ring 5 are all arranged in one-to-one correspondence and are evenly distributed along the circumference of the light-blocking rings. The connecting shafts 6 are as shown in FIG. Fig.10 As shown, the connecting shaft 6 is used to connect the light-blocking ring and the connecting beam 3, forming a rotation node between the light-blocking ring and the connecting beam 3, and is fixed to the light-blocking ring by a retaining spring to limit axial movement. The opposite ends of each two corresponding connecting beams 3 are respectively fixedly connected to the corresponding ends of the corresponding elbow joints 4; the top light-blocking ring 2 is glued to the upper end of the light-shielding film 1, the bottom light-blocking ring 8 is glued to the lower end of the light-shielding film 1, and each middle light-blocking ring 5 is glued to the middle end of the light-shielding film 1. The movement of the top light-blocking ring 2 drives the light-shielding film 1 to unfold.

[0054] The top and outer ring of the top light-blocking ring 2 are glued to the light-shielding film 1, and light enters from the inner ring of the top light-blocking ring 2, which plays a primary light-extinction role.

[0055] The middle light blocking ring 5 plays a secondary light extinction role.

[0056] The lower end of the bottom light-blocking ring 8 is fixed to the single-machine equipment by bolts, playing a three-level extinction effect.

[0057] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0058] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A deployable cylindrical sunshade based on a shape memory polymer composite material, characterized in that: It comprises an elbow-shaped joint truss and a light-shielding film (1); the outer side of the elbow-shaped joint truss is coated with an origami-expanded light-shielding film (1).

2. The expandable cylindrical sunshade based on a shape memory polymer composite material according to claim 1, characterized in that: The elbow-shaped joint truss comprises a top light-blocking ring (2), a connecting beam (3), an elbow-shaped joint (4) and a bottom light-blocking ring (8); the top light-blocking ring (2) and the bottom light-blocking ring (8) are arranged horizontally in parallel up and down, the bottom end of the top light-blocking ring (2) and the top end of the bottom light-blocking ring (8) are respectively hinged to one end of a corresponding plurality of connecting beams (3), the plurality of connecting beams (3) on the top light-blocking ring (2) and the plurality of connecting beams (3) on the bottom light-blocking ring (8) are arranged in a one-to-one correspondence, and the opposite ends of every two corresponding connecting beams (3) are respectively fixedly connected to the corresponding ends of the corresponding elbow-shaped joint (4); the top light-blocking ring (2) is glued to the upper end of the light-shielding film (1), and the bottom light-blocking ring (8) is glued to the lower end of the light-shielding film (1).

3. The expandable cylindrical sunshade based on a shape memory polymer composite material according to claim 1, characterized in that: The elbow-shaped joint truss comprises a top light blocking ring (2), a connecting beam (3), an elbow-shaped joint (4), a middle light blocking ring (5) and a bottom light blocking ring (8); the top light blocking ring (2) and the bottom light blocking ring (8) are arranged horizontally in parallel vertically, and a plurality of middle light blocking rings (5) are arranged horizontally in parallel vertically between the top light blocking ring (2) and the bottom light blocking ring (8); the bottom end of the top light blocking ring (2), the top end of the bottom light blocking ring (8) and the upper end and the lower end of each middle light blocking ring (5) are respectively connected to the corresponding plurality of connecting beams (3). One end of the light-blocking ring (2) is hinged, and a plurality of connecting beams (3) on the top light-blocking ring (2), a plurality of connecting beams (3) on the bottom light-blocking ring (8), and a plurality of connecting beams (3) on each middle light-blocking ring (5) are arranged in a one-to-one correspondence, and the opposite ends of every two corresponding connecting beams (3) are respectively fixedly connected to the corresponding ends of the corresponding elbow-shaped joints (4); the top light-blocking ring (2) is glued to the upper end of the light-blocking film (1), the bottom light-blocking ring (8) is glued to the lower end of the light-blocking film (1), and each middle light-blocking ring (5) is glued to the middle end of the light-blocking film (1).

4. The expandable cylindrical sunshade based on a shape memory polymer composite material according to claim 2 or 3, characterized in that: The elbow joint (4) comprises two end fixings (4-1), two shape memory polymer composite sheets (4-2) and two heating films (4-3); the two shape memory polymer composite sheets (4-2) are arranged in parallel inside and outside, the two ends of the two shape memory polymer composite sheets (4-2) are respectively fixedly connected to the corresponding end fixings (4-1), the outer wall of each shape memory polymer composite sheet (4-2) is fixedly connected to the heating film (4-3), and each end fixing (4-1) is respectively fixedly connected to the corresponding end of the corresponding connecting beam (3).

5. A method for operating the deployable cylindrical sunshade based on a shape memory polymer composite material according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: S1: Turn on the heating switch to energize the heating film (4-3) on one side; S2: When the temperature reaches the glass transition temperature of the shape memory polymer composite material, the stiffness of the shape memory polymer material decreases, and driven by the shape memory restoring force, the shape memory polymer composite sheet (4-2) recovers from a bent state to a straight state; S3: The elbow joint (4) drives the elbow joint truss to extend; S4: driving the light shielding film (1) to unfold; S5: Turn off the heating switch of the heating film (4-3); S6: The surface temperature of the shape memory polymer composite material is reduced and the stiffness of the shape memory polymer material is increased, ensuring that the deployable sunshade is in a locked state.

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