A single degree of freedom conoid-like deployable structure

Abstract

The present application provides a single degree of freedom conical-like deployable structure, which is used to solve the technical problems of low deployment precision and low structural stiffness of the existing conical deployable optical shield, and the existing optical shield with high stiffness cannot cope with the technical problem of gradient transformation of the radial size of the conical configuration along the axial direction. The single degree of freedom conical-like deployable structure provided by the present application comprises a plurality of folding and deploying branch chains, and each folding and deploying branch chain comprises a plurality of folding and deploying units connected in sequence from top to bottom. The single folding and deploying branch chain is designed to rotate around itself by designing the upper folding and deploying part and the lower folding and deploying part in the folding and deploying unit. The single degree of freedom conical-like deployable structure is formed by connecting the first coupling platform and the second coupling platform with the top end and the bottom end of the folding and deploying branch chain. The single degree of freedom conical-like deployable structure can be equivalent to a spatial Sarrus mechanism comprising a plurality of folding and deploying branch chains, and realizes the single degree of freedom folding and deployment of the conical-like deployable structure along the axial direction, and perfectly adapts to the conical field of view of the large field of view of the optical load.

Description

Technical Field

[0001] This invention relates to deployable structures, and more specifically to a single-degree-of-freedom cone-shaped deployable structure. Background Technology

[0002] Deployable structures are a novel type of structure with diverse configuration variations. Driven by external force, they can gradually unfold from a folded state to a fully deployed state, and then lock into a stable working state. Depending on the application and operating method, deployable structures can be designed with planar, parabolic, and cylindrical surfaces. Among these, the cylindrical surface, as a closed curved surface around an axis, provides effective protection for aerospace equipment and is therefore often used in space equipment with high environmental requirements, such as sunshades and light shields for optical payloads. With the development of space exploration missions, optical cameras are trending towards larger fields of view. The cylindrical surface configuration can no longer meet the needs of large-field-of-view optical payloads, thus creating a new requirement for the envelope of optical payload components such as sunshades and light shields to evolve from a cylindrical to a conical shape. Unlike the cylindrical surface configuration, which can be achieved through one-dimensional unfolding, the conical configuration has the characteristic of radial dimensions varying with an axial gradient. This requires the motion trajectory of the deployable structure to cover three-dimensional space. However, most existing research on cylindrical surface configurations uses traditional planar mechanisms as the basic unit for unfolding, and their planar motion characteristics are difficult to adapt to the axial and radial coupling expansion mode of the conical configuration.

[0003] Currently, existing deployable cone-shaped light shields mainly employ rigid frames, elastic materials, and inflatable composite materials. However, these solutions suffer from low deployment accuracy and low structural stiffness. Existing light shields with higher stiffness, such as spring-driven cone-shaped light shields, can only be applied to smaller-sized space optical systems and cannot address the technical challenges of requiring radial dimension gradient transformation along the axial direction in large-sized space optical systems. Therefore, a rigid, cone-like deployable structure suitable for large-sized applications, applicable to cone-like light shield structures, is needed to fill this gap in the field. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of low deployment accuracy and low structural stiffness of existing conical deployable light shields, while light shields with high stiffness cannot cope with the technical difficulty of the radial dimension of the conical configuration being gradient along the axial direction when used in large-size space optical systems. Therefore, this invention provides a single-degree-of-freedom conical deployable structure.

[0005] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0006] A single-degree-of-freedom cone-shaped deployable structure, characterized in that it includes M folding branches, multiple first connecting joints, multiple second connecting joints, a first coupling connecting platform, and a second coupling connecting platform, where M≥3;

[0007] The unfolded branch is a flat plate structure in the shape of an inverted isosceles trapezoid in its unfolded state, which includes N unfolded units connected sequentially from top to bottom, where N≥2; each unfolded unit is a flat plate structure in the shape of an inverted isosceles trapezoid in its unfolded state.

[0008] The folding unit includes an upper folding section and a lower folding section; the upper folding section includes a first main board in the shape of an inverted isosceles trapezoid and two first folding plates in the shape of trapezoids, which are symmetrically hinged to both sides of the first main board by a first connecting joint, and the upper and lower ends of the first main board and the first folding plates are flush with each other; the lower folding section includes a second main board in the shape of an isosceles trapezoid and two second folding plates in the shape of inverted trapezoids, which are symmetrically hinged to both sides of the second main board by a first connecting joint, and the upper and lower ends of the second main board and the second folding plates are flush with each other;

[0009] In the same folding unit, the short base of the first main board is equal to and corresponding to the short base of the second main board; the long base of the first folding plate on the same side is equal to the long base of the second folding plate and is hinged by the first connecting joint; the short bases of the two second folding plates in each folding unit are equal to the short bases of the two first folding plates in the next folding unit and are hinged by the first connecting joint; the long base of the second main board in each folding unit is equal to the long base of the first main board in the next folding unit, and there is a clearance between them; the first folding plates on both sides and the second folding plates on both sides in the same folding unit do not interfere with each other when folded.

[0010] Both the first and second coupling connection platforms are flat plate structures, and each has a light-transmitting hole at its center. The first coupling connection platform is connected to the top of the first main board of the first folding unit in the M folding branches through the second connection joint. The second coupling connection platform is connected to the bottom of the second main board of the Nth folding unit in the M folding branches through the second connection joint, so that the M folding branches, the first coupling connection platform, and the second coupling connection platform are combined to form a cone-shaped deployable structure.

[0011] Furthermore, at least one of the plurality of first connecting joints is a drive-type connecting joint.

[0012] Furthermore, mounting grooves are provided at the positions where the first folding plate connects to the outer wall of the first main board, the second folding plate connects to the outer wall of the second main board, the first folding plate connects to the inner wall of the second folding plate in the same folding unit, and the second folding plate connects to the outer wall of the first folding plate in adjacent folding units.

[0013] Multiple first connecting joints are respectively installed in corresponding mounting slots.

[0014] Furthermore, a first protrusion is provided on the outer wall surface at the position corresponding to the short bottom of the second folding plate in the first to N-1 folding units, and a second protrusion is provided on the outer wall surface at the position corresponding to the short bottom of the first folding plate in the second to N folding units;

[0015] The first boss and the second boss are respectively provided with mounting grooves;

[0016] The first connecting joint is installed in the corresponding mounting slot to achieve the hinge connection between the second folding plate and the short bottom of the first folding plate in the adjacent unfolding unit.

[0017] Furthermore, the folding branch is a thick-plate paper-cutting array designed using a thick-plate paper-cutting folding method.

[0018] Furthermore, the thick-plate paper-cutting array is formed by multiple U1 units and multiple U2 units arranged alternately from top to bottom, and connected by a common crease coupling;

[0019] The U1 unit includes U1 A Part and U1 B Part of the U2 unit includes U2 B Part and U2 A Part; U1 in the first U1 unit A The structure of the upper folding section in the first folding unit is the same, and its U1 B The structure of the lower folding section in the first folding unit is the same as that in the first U1 unit. A Part of U1 B The connection relationship of some parts is the same as the connection relationship between the upper and lower folded parts in the first folded unit; the U2 in the first U2 unit B Part of it has the same structure as the lower folding section in the first folding unit, its U2 A The structure of the upper folding section in the first U2 unit is the same as that in the second folding unit. B Part of U2 A The connection relationship is the same as that between the lower folding part in the first folding unit and the upper folding part in the second folding unit; to ensure that there is no interference in the thickness direction during the folding process, the U2 in the first U2 unit is removed. B Partially, and the U1 in the first U1 unit A Part of U1 B The connection points are coupled together as a shared crease between the first U1 unit and the first U2 unit;

[0020] U2 in the first U2 unit A The structure of the upper folding section in the second folding unit is the same as that in the second U1 unit. APart of the structure is the same as the upper folding section in the second folding unit, and the U1 in the second U1 unit is also the same. B Part of the structure is the same as the lower folding section in the second folding unit, and U1 in the second U1 unit A Part of U1 B The connection relationship of some parts is the same as the connection relationship between the upper and lower folding parts in the second folding unit; in order to ensure that there is no interference in the thickness direction during the folding process, U1 in the second U1 unit is removed. A Partially, and the U2 in the first U2 unit B Part of U2 A The connection point is used as a shared crease between the first U2 unit and the second U1 unit for coupling connection;

[0021] Similarly, multiple U1 units and multiple U2 units are arranged alternately from top to bottom, and they share a common crease to achieve coupling connection.

[0022] Furthermore, let's define the axis connecting the first connecting joint between the left first folding plate and the first main board as folding axis A, the axis connecting the first connecting joint between the right first folding plate and the first main board as folding axis B, the axis connecting the first connecting joint between the left second folding plate and the second main board as folding axis C, and the axis connecting the first connecting joint between the right second folding plate and the second main board as folding axis D. Simultaneously, let's define the axis connecting the first connecting joint between the long bottom of the first folding plate and the long bottom of the second folding plate in the same folding unit as crease axis E, and the axis connecting the first connecting joint between the short bottom of the second folding plate and the short bottom of the first folding plate in adjacent folding units as crease axis F. Then, the angle between folding axis A and crease axis E is α1. The first main board... The angle between the short base and the crease axis E is α2; the angle between the folding axis B and the crease axis E is α3; the angle between the folding axis D and the crease axis E is α4; the angle between the short base of the second main plate and the crease axis E is α5; the angle between the folding axis C and the crease axis E is α6; the angle between the folding axis C and the crease axis F is β1; the angle between the folding axis C and the folding axis D is β2; the angle between the folding axis D and the crease axis F is β3; the angle between the folding axis B and the crease axis F is β4; the angle between the folding axis B and the folding axis A is β5; the angle between the folding axis A and the crease axis F is β6; additionally, the thickness of the first folding plate on the left is defined as t. 1-U1 Its base length is L 1-U1 The thickness of the first folding plate on the right is t. 2-U1 Its base length is L 2-U1 The thickness of the second fold plate on the right is t. 3-U1 Its base length is L 2-U2 The thickness of the second fold plate on the left is t. 4-U1 Its long base length is L 1-U2Define the total thickness of the second fold plate on the left and the first boss at the corresponding position as t. 1-U2 The total thickness of the second fold plate on the right and the corresponding first protrusion is t. 2-U2 The total thickness of the first folding plate on the right and the corresponding second protrusion is t. 3-U2 The total thickness of the first folding plate on the left and the corresponding second protrusion is t. 4-U2 ;

[0023] Each parameter must meet the following conditions:

[0024] ;

[0025] ;

[0026] .

[0027] Furthermore, the height of the second motherboard in the same folding unit is less than the height of the first motherboard, and the height of the first motherboard in each folding unit is less than the height of the first motherboard in the next folding unit.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] 1. The present invention provides a single-degree-of-freedom cone-shaped deployable structure, comprising multiple folding branches, and each folding branch further comprising multiple folding units connected sequentially from top to bottom. By designing the upper and lower folding portions in the folding units, a single folding branch can rotate around itself. Combined with the connection of the first coupling connection platform and the second coupling connection platform to the top and bottom ends of the folding branches, a cone-shaped deployable structure is formed. This cone-shaped deployable structure can be equivalent to a spatial Sarrus mechanism containing multiple folding branches, thereby realizing the folding and unfolding of the cone-shaped deployable structure along the axial direction with a single degree of freedom.

[0030] 2. The present invention provides a single-degree-of-freedom cone-shaped deployable structure. In the fully deployed state, each folded branch forms a fully deployed flat state, which can perfectly adapt to the cone-shaped field of view with a large field of view of the optical load. At the same time, since each folded branch unfolds into a flat configuration in the fully deployed state, the cone-shaped deployable structure is in the dead point configuration of the mechanism, which can achieve self-locking limit in this state.

[0031] 3. The present invention provides a single-degree-of-freedom cone-shaped deployable structure, which contains only a plurality of first connecting joints and a plurality of second connecting joints. At least one of the plurality of first connecting joints is designed as a drive-type connecting joint. It can realize the deployment motion of the cone-shaped deployable structure along the axial direction without the need for a sliding pair, and can be widely used in the field of aerospace engineering.

[0032] 4. The present invention provides a single-degree-of-freedom cone-shaped expandable structure, wherein the folding branch is a thick plate paper-cutting array designed using a thick plate paper-cutting folding method. This structure can achieve infinite expansion in one direction, thereby realizing the single-degree-of-freedom expansion of the entire cone-shaped expandable structure.

[0033] 5. The present invention provides a single-degree-of-freedom cone-shaped deployable structure, which connects a first coupling connection platform and a second coupling connection platform through multiple folding and unfolding branches, and can form a spatial single-degree-of-freedom Sarrus mechanism. During launch, it folds and retracts to achieve a small spatial volume, and unfolds and locks when it reaches the expected position in orbit. This not only provides a new idea for the in-orbit application of large-size light shields with cone-shaped field of view, but can also be extended to other deployable structure fields, such as robotic arms, protective shields, etc. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of an embodiment of a single-degree-of-freedom cone-shaped deployable structure according to the present invention;

[0035] Figure 2 This is a schematic diagram of the structure of the folded branch in the fully unfolded state in an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of the structure of the folding branch in the semi-folded state in an embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram illustrating the unfolding process of a single folding branch from a fully folded state to a fully unfolded state in an embodiment of the present invention.

[0038] Figure 5 This is a schematic diagram illustrating the principle of the folding and unfolding branch chain of the thick-plate paper-cutting array formed by multiple U1 units and U2 units arranged alternately from top to bottom and sharing a common fold line coupling connection in an embodiment of the present invention.

[0039] Figure 6 This is a schematic diagram of the parameters of unit U1 in an embodiment of the present invention;

[0040] Figure 7 This is a schematic diagram of the parameters of unit U2 in an embodiment of the present invention;

[0041] Figure 8 This is a schematic diagram of the semi-folded state of the cone-shaped expandable structure in an embodiment of the present invention, wherein (a) is a three-dimensional structural schematic diagram of the semi-folded state, and (b) is an equivalent schematic diagram of the semi-folded state.

[0042] Figure 9 This is a schematic diagram illustrating the unfolding process of the cone-shaped deployable structure from a fully folded state to a fully unfolded state in an embodiment of the present invention. Figure 1 (3D structural diagram);

[0043] Figure 10 This is a schematic diagram illustrating the unfolding process of the cone-shaped deployable structure from a fully folded state to a fully unfolded state in an embodiment of the present invention. Figure 2 (Planar structure diagram).

[0044] The annotations in the attached figures are explained as follows:

[0045] 1-Folding branch chain; 11-First main board; 12-First folding plate; 13-Second main board; 14-Second folding plate; 2-First connecting joint; 3-Second connecting joint; 4-First coupling connecting platform. Detailed Implementation

[0046] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0047] like Figure 1 As shown, a single-degree-of-freedom cone-shaped deployable structure, serving as a large-size light shield with a cone-shaped field of view, specifically includes six deployable branches 1, multiple first connecting joints 2, multiple second connecting joints 3, a first coupling connecting platform 4, and a second coupling connecting platform. Each deployable branch 1 includes five deployable units connected sequentially from top to bottom, and each deployable branch 1 as a whole is an isosceles inverted trapezoidal flat plate structure in its deployed state.

[0048] like Figure 2 , Figure 3 As shown, each unfolding unit is also a flat plate structure in the shape of an inverted isosceles trapezoid in its unfolded state. The unfolding unit includes an upper unfolding section and a lower unfolding section. The upper unfolding section includes a first main plate 11 in the shape of an inverted isosceles trapezoid and two first folding plates 12, which are symmetrically hinged to both sides of the first main plate 11 using first connecting joints 2 and are also trapezoidal in shape. The upper and lower ends of the first main plate 11 and the first folding plates 12 are flush. The lower unfolding section includes a second main plate 13 in the shape of an isosceles trapezoid and two second folding plates 14, which are symmetrically hinged to both sides of the second main plate 13 using first connecting joints 2 and are also inverted trapezoidal in shape. The upper and lower ends of the second main plate 13 and the second folding plates 14 are also flush. In the same unfolding unit, the height of the second main plate 13 is less than the height of the first main plate 11, and the height of the first main plate 11 in each unfolding unit is less than the height of the first main plate 11 in the next unfolding unit, so that the entire unfolding unit also has the shape of an inverted isosceles trapezoid in its unfolded state.

[0049] In the same folding unit, the short base of the first main board 11 is equal to and corresponding to the short base of the second main board 13. In the same folding unit, the long base of the first folding plate 12 on the same side is equal to the long base of the second folding plate 14 and is hinged via the first connecting joint 2. The short bases of the two second folding plates 14 in each folding unit are equal to the short bases of the two first folding plates 12 in the next folding unit and are correspondingly hinged via the first connecting joint 2. Furthermore, a clearance gap is provided between the long base of the second main board 13 in each folding unit and the long base of the first main board 11 in the next folding unit. Additionally, the first folding plates 12 on both sides and the second folding plates 14 on both sides in the same folding unit do not interfere with each other when folded.

[0050] Preferably, mounting grooves are provided at the connection points of the outer walls of the first folding plate 12 and the first main plate 11, the connection points of the outer walls of the second folding plate 14 and the second main plate 13, and the connection points of the inner walls of the first folding plate 12 and the second folding plate 14 in the same folding unit. Multiple first connecting joints 2 are installed in their respective mounting grooves to avoid internal self-intersecting interference in the fully folded state. Simultaneously, a first protrusion is provided on the outer wall surface corresponding to the short bottom of each second folding plate 14 in the first to fourth folding units, and a second protrusion is provided on the outer wall surface corresponding to the short bottom of each first folding plate 12 in the second to fifth folding units. Mounting grooves are provided on the first and second protrusions, and multiple other first connecting joints 2 are installed in their respective mounting grooves to achieve hinged connection between the short bottoms of the second folding plate 14 and the first folding plate 12 in adjacent folding units.

[0051] The process of a single folding branch 1 from complete folding to complete unfolding is as follows: Figure 4 As shown, in the fully folded state, the first main plate 11, the first folding plate 12, the second main plate 13, and the second folding plate 14 in the unfolding branch 1 are arranged parallel and compactly to each other, forming an inverted trapezoidal folding configuration. The surfaces of the first main plate 11, the first folding plate 12, the second main plate 13, and the second folding plate 14 rotate around their respective first connecting joint axes to unfold the unfolding branch 1; in the fully unfolded state, the unfolding branch 1 is flattened as a whole, forming an isosceles inverted trapezoidal configuration with a planar structure.

[0052] Both the first coupling connection platform 4 and the second coupling connection platform are flat plate structures, and each has a light-transmitting hole at its center. Second connecting joints 3 are added to the top and bottom of the six folding branches 1. The top of the first main board 11 of the first folding unit in the six folding branches 1 is connected to the first coupling connection platform 4 via its respective second connecting joint 3. The bottom of the second main board 13 of the fifth folding unit in the six folding branches 1 is connected to the second coupling connection platform via its respective second connecting joint 3. This allows the six folding branches 1, the first coupling connection platform 4, and the second coupling connection platform to form a cone-shaped deployable structure. In its fully unfolded state, the folding branches 1 fit together perfectly to form a closed polygon, providing stray light protection for the cone-shaped field of view of the space optical camera.

[0053] In this invention, the unfolding branch 1 is a thick-plate paper-cutting array designed using a thick-plate paper-cutting folding method. The thick-plate paper-cutting array is formed by multiple U1 units and multiple U2 units arranged alternately from top to bottom and connected by a common fold line. Therefore, the unfolding branch 1 can achieve infinite expansion in one direction, thereby realizing the single degree of freedom expansion of the entire cone-shaped unfoldable structure.

[0054] like Figure 5 As shown, unit U1 includes U1 A Part and U1 B Part of the U2 unit includes U2 B Part and U2 A Partial. Following the top-to-bottom order, the first U1 unit contains U1. A Part of it is equivalent to the upper folding section of the first folding unit, its U1 B Part equivalent to the lower folded section of the first folded unit, U1 in the first U1 unit A Part of U1 B The connection relationship of some parts is the same as the connection relationship between the upper and lower folded parts in the first folded unit; the U2 in the first U2 unit B This part is also equivalent to the lower folding section of the first folding unit, its U2 A This part is equivalent to the upper folding section in the second folding unit, and the U2 in the first U2 unit. B Part of U2 A The connection relationship of some parts is the same as the connection relationship between the lower folded part in the first folded unit and the upper folded part in the second folded unit; because U1 in the first U1 unit B Part of the U2 in the first U2 unit B Since some structures are identical and designed in the same location, to ensure that there is no interference in the thickness direction during the unfolding process, one of the identical structures is removed. For example, the U2 element in the first U2 unit is removed. BPartially, and the U1 in the first U1 unit A Part of U1 B The connection point is coupled together as a shared crease between the first U1 unit and the first U2 unit. The U2 in the first U2 unit... A This part corresponds to the upper folding section in the second folding unit, and U1 in the second U1 unit. A This part is also equivalent to the upper folding section in the second folding unit, and the U1 in the second U1 unit. B Part of it corresponds to the lower folded section of the second folded unit, U1 in the second U1 unit A Part of U1 B The connection relationship of the part is the same as the connection relationship between the upper and lower folded parts in the second folded unit; because of the U2 in the first U2 unit A Part of U1 in the second U1 unit A Since some structures are identical and designed in the same location, to ensure that there is no interference in the thickness direction during the unfolding process, the U1 element in the second U1 unit is removed. A Partially, and the U2 in the first U2 unit B Part of U2 A The connection point serves as a shared crease between the first U2 unit and the second U1 unit for coupling connection. This process is repeated, with multiple U1 units and multiple U2 units arranged alternately from top to bottom, and the shared creases achieving alternating coupling connections.

[0055] Taking one of the folded units as an example, such as Figure 6 , Figure 7As shown, the axis connecting the first connecting joint 2 between the left first folding plate 12 and the first main plate 11 is defined as folding axis A; the axis connecting the first connecting joint 2 between the right first folding plate 12 and the first main plate 11 is defined as folding axis B; the axis connecting the first connecting joint 2 between the left second folding plate 14 and the second main plate 13 is defined as folding axis C; and the axis connecting the first connecting joint 2 between the right second folding plate 14 and the second main plate 13 is defined as folding axis D. Simultaneously, the axis connecting the first connecting joint 2 between the long bottom of the first folding plate 12 and the long bottom of the second folding plate 14 in the same folding unit is defined as crease axis E; and the axis connecting the first connecting joint 2 between the short bottom of the second folding plate 14 and the short bottom of the first folding plate 12 in adjacent folding units is defined as crease axis F. Therefore, the folding axes... The angle between A and the crease axis E is α1; the angle between the short bottom of the first main plate 11 and the crease axis E is α2; the angle between folding axis B and the crease axis E is α3; the angle between folding axis D and the crease axis E is α4; the angle between the short bottom of the second main plate 13 and the crease axis E is α5; the angle between folding axis C and the crease axis E is α6; the angle between folding axis C and the crease axis F is β1; the angle between folding axis C and folding axis D is β2; the angle between folding axis D and crease axis F is β3; the angle between folding axis B and crease axis F is β4; the angle between folding axis B and folding axis A is β5; and the angle between folding axis A and crease axis F is β6. Additionally, the thickness of the first folding plate 12 on the left is defined as t. 1-U1 Its long base length is L 1-U1 The thickness of the first folding plate 12 on the right is t. 2-U1 Its long base length is L 2-U1 The thickness of the second folding plate 14 on the right is t. 3-U1 Its long base length is L 2-U2 The thickness of the second folding plate 14 on the left is t. 4-U1 Its long base length is L 1-U2 Define the total thickness of the second fold plate 14 on the left and the corresponding first protrusion as t. 1-U2 The total thickness of the second folding plate 14 on the right and the corresponding first protrusion is t. 2-U2 The total thickness of the first folding plate 12 on the right side and the corresponding second protrusion is t. 3-U2 The total thickness of the first folding plate 12 on the left and the corresponding second protrusion is t. 4-U2 .

[0056] Since each folding unit in folding branch 1 needs to achieve complete folding and unfolding, its design parameters need to meet the following conditions:

[0057] Unit U1: ;

[0058] Unit U2: .

[0059] When the above conditions are met, a single folded branch 1 can be kinematically equivalent to the network form of a 6R Waldorn spatial over-constrained mechanism.

[0060] Meanwhile, since the folded branch 1 is formed by alternating arrangement of multiple U1 units and multiple U2 units from top to bottom, and is connected by a shared fold line, it needs to satisfy: L 1-U1 =L 1-U2 L 2-U1 = L 2-U2 Since the U1 and U2 units share a crease coupling connection, the unfolding branch 1 can achieve folding and unfolding with a single degree of freedom.

[0061] Figure 8 The diagram shows a semi-folded state of a cone-shaped deployable structure. (a) is a three-dimensional schematic of the semi-folded state, and (b) is an equivalent schematic. In the equivalent schematic, the virtual axis R on a single folding branch 1 is a single-degree-of-freedom revolute joint rotating about itself, and it is parallel to the joint axis connecting the first coupling platform 4 and the second coupling platform. At this point, the cone-shaped deployable structure can be considered as a network structure containing six folding branches 1. From a kinematic perspective, it can be considered as a spatial Sarrus mechanism containing six folding branches 1. Correspondingly, this network structure can also achieve single-degree-of-freedom motion, i.e., folding and unfolding the cone-shaped deployable structure along its axial direction. A schematic diagram of the process from complete folding to complete unfolding of the cone-shaped deployable structure is shown below. Figure 9 , Figure 10 As shown.

[0062] Specifically, the folding and unfolding process of this type of conical deployable structure is achieved through the folding and unfolding movements of each folding and unfolding branch 1. In its fully folded state, each folding and unfolding branch 1 is in a folded and compressed state. The unfolding process of each folding and unfolding branch 1 is achieved by inputting the rotation angle at each connecting joint position. In the fully unfolded state, each folding and unfolding branch 1 forms a fully unfolded flat state. At this time, this type of conical deployable structure forms a fully unfolded polygonal conical configuration, which can adapt to a conical field of view with a large field of view. At the same time, since each folding and unfolding branch 1 is fully unfolded into a flat configuration, this type of conical deployable structure is precisely in the dead point configuration of the mechanism, which can achieve self-locking limit in this state.

[0063] Since the spatial Sarrus mechanism containing multiple folding branches 1 has a single degree of freedom, some of the multiple first connecting joints 2 can be set as driving connecting joints, such as torsion spring driven joints, to provide driving torque for the unfolding process, so as to drive the single degree of freedom cone-shaped deployable structure to be deployed from the fully folded state.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A single-degree-of-freedom cone-shaped developable structure, characterized in that: It includes M folding branches (1), multiple first connecting joints (2), multiple second connecting joints (3), a first coupling connecting platform (4), and a second coupling connecting platform, where M≥3; The unfolded branch (1) is a flat plate structure in the unfolded state of an inverted isosceles trapezoid, which includes N unfolded units connected from top to bottom, where N≥2; each unfolded unit is a flat plate structure in the unfolded state of an inverted isosceles trapezoid. The folding unit includes an upper folding section and a lower folding section; the upper folding section includes a first main board (11) in the shape of an inverted isosceles trapezoid and two first folding plates (12) in the shape of trapezoids, which are symmetrically hinged to both sides of the first main board (11) by a first connecting joint (2), and the upper and lower ends of the first main board (11) and the first folding plates (12) are flush; the lower folding section includes a second main board (13) in the shape of an isosceles trapezoid and two second folding plates (14) in the shape of inverted trapezoids, which are symmetrically hinged to both sides of the second main board (13) by a first connecting joint (2), and the upper and lower ends of the second main board (13) and the second folding plates (14) are flush; In the same folding unit, the short bottom of the first main board (11) is equal to and corresponding to the short bottom of the second main board (13), and the long bottom of the first folding plate (12) on the same side is equal to the long bottom of the second folding plate (14) and is hinged through the first connecting joint (2); the short bottom of the two second folding plates (14) in each folding unit is equal to the short bottom of the two first folding plates (12) in the next folding unit and is hinged through the first connecting joint (2); the long bottom of the second main board (13) in each folding unit is equal to the long bottom of the first main board (11) in the next folding unit, and there is a clearance between them; Both the first coupling connection platform (4) and the second coupling connection platform are flat plate structures, and light-transmitting holes are respectively opened at their center positions. The first coupling connection platform (4) is connected to the top of the first main board (11) of the first folding unit in the M folding branches (1) through the second connection joint (3). The second coupling connection platform is connected to the bottom of the second main board (13) of the Nth folding unit in the M folding branches (1) through the second connection joint (3), so that the M folding branches (1), the first coupling connection platform (4), and the second coupling connection platform are combined to form a cone-shaped deployable structure.

2. The single-degree-of-freedom cone-shaped developable structure according to claim 1, characterized in that: At least one of the multiple first connecting joints (2) is a drive-type connecting joint.

3. The single-degree-of-freedom cone-shaped developable structure according to claim 2, characterized in that: Mounting grooves are provided at the following locations: the first folding plate (12) and the outer wall of the first main plate (11) corresponding to their connection point; the second folding plate (14) and the outer wall of the second main plate (13) corresponding to their connection point; the inner wall of the first folding plate (12) and the second folding plate (14) in the same folding unit corresponding to their connection point; and the second folding plate (14) and the outer wall of the first folding plate (12) in adjacent folding units corresponding to their connection point. Multiple first connecting joints (2) are respectively installed in corresponding mounting slots.

4. The single-degree-of-freedom cone-shaped developable structure according to claim 3, characterized in that: A first protrusion is provided on the outer wall surface of the second fold plate (14) at the corresponding position of the short bottom in each of the first to N-1 folding units, and a second protrusion is provided on the outer wall surface of the first fold plate (12) at the corresponding position of the short bottom in each of the second to N-1 folding units; The first boss and the second boss are respectively provided with mounting grooves; The first connecting joint (2) is installed in the corresponding mounting slot to achieve the hinge connection between the second folding plate (14) and the short bottom of the first folding plate (12) in the adjacent unfolding unit.

5. The single-degree-of-freedom cone-shaped developable structure according to claim 4, characterized in that: The folding branch (1) is a thick-plate paper-cutting array designed using a thick-plate paper-cutting folding method.

6. The single-degree-of-freedom cone-shaped developable structure according to claim 5, characterized in that: The thick-plate paper-cutting array is formed by multiple U1 units and multiple U2 units arranged alternately from top to bottom, and connected by a common crease coupling. The U1 unit includes U1 A Part and U1 B Part of the U2 unit includes U2 B Part and U2 A Part; U1 in the first U1 unit A The structure of the upper folding section in the first folding unit is the same, and its U1 B The structure of the lower folding section in the first folding unit is the same as that in the first U1 unit. A Part of U1 B The connection relationship of some parts is the same as the connection relationship between the upper and lower folded parts in the first folded unit; the U2 in the first U2 unit B Part of it has the same structure as the lower folding section in the first folding unit, its U2 A The structure of the upper folding section in the first U2 unit is the same as that in the second folding unit. B Part of U2 A The connection relationship is the same as that between the lower folding part in the first folding unit and the upper folding part in the second folding unit; to ensure that there is no interference in the thickness direction during the folding process, the U2 in the first U2 unit is removed. B Partially, and the U1 in the first U1 unit A Part of U1 B The connection points are coupled together as a shared crease between the first U1 unit and the first U2 unit; U2 in the first U2 unit A The structure of the upper folding section in the second folding unit is the same as that in the second U1 unit. A Part of the structure is the same as the upper folding section in the second folding unit, and the U1 in the second U1 unit is also the same. B Part of the structure is the same as the lower folding section in the second folding unit, and U1 in the second U1 unit A Part of U1 B The connection relationship of some parts is the same as the connection relationship between the upper and lower folding parts in the second folding unit; in order to ensure that there is no interference in the thickness direction during the folding process, U1 in the second U1 unit is removed. A Partially, and the U2 in the first U2 unit B Part of U2 A The connection point is used as a shared crease between the first U2 unit and the second U1 unit for coupling connection; Similarly, multiple U1 units and multiple U2 units are arranged alternately from top to bottom, and they share a common crease to achieve coupling connection.

7. The single-degree-of-freedom cone-shaped developable structure according to claim 6, characterized in that: Define the axis of the first connecting joint (2) connecting the first folding plate (12) on the left and the first main plate (11) as the folding axis A, the axis of the first connecting joint (2) connecting the first folding plate (12) on the right and the first main plate (11) as the folding axis B, the axis of the first connecting joint (2) connecting the second folding plate (14) on the left and the second main plate (13) as the folding axis C, and the axis of the first connecting joint (2) connecting the second folding plate (14) on the right and the second main plate (13) as the folding axis D. At the same time, define the axis of the first connecting joint (2) connecting the long bottom of the first folding plate (12) and the long bottom of the second folding plate (14) in the same folding unit as the crease axis E, and the axis of the first connecting joint (2) connecting the short bottom of the second folding plate (14) and the short bottom of the first folding plate (12) in adjacent folding units as the crease axis F. The angle between folding axis A and crease axis E is α1; the angle between the short bottom of the first main board (11) and crease axis E is α2; the angle between folding axis B and crease axis E is α3; the angle between folding axis D and crease axis E is α4; the angle between the short bottom of the second main board (13) and crease axis E is α5; the angle between folding axis C and crease axis E is α6; the angle between folding axis C and crease axis F is β1; the angle between folding axis C and folding axis D is β2; the angle between folding axis D and crease axis F is β3; the angle between folding axis B and crease axis F is β4; the angle between folding axis B and folding axis A is β5; the angle between folding axis A and crease axis F is β6; in addition, the thickness of the first folding plate (12) on the left is defined as t. 1-U1 Its base length is L 1-U1 The thickness of the first fold plate (12) on the right is t. 2-U1 Its base length is L 2-U1 The thickness of the second fold plate (14) on the right is t. 3-U1 Its base length is L 2-U2 The thickness of the second fold plate (14) on the left is t. 4-U1 Its base length is L 1-U2 Define the total thickness of the second fold plate (14) on the left and the first protrusion at the corresponding position as t. 1-U2 The total thickness of the second fold plate (14) on the right side and the first protrusion at the corresponding position is t. 2-U2 The total thickness of the first fold plate (12) on the right side and the corresponding second protrusion is t. 3-U2 The total thickness of the first folding plate (12) on the left and the corresponding second protrusion is t. 4-U2 ; Each parameter must meet the following conditions: ； ； 。 8. The single-degree-of-freedom cone-shaped developable structure according to claim 7, characterized in that: The height of the second motherboard (13) in the same folding unit is less than the height of the first motherboard (11), and the height of the first motherboard (11) in each folding unit is less than the height of the first motherboard (11) in its next folding unit.

Images