Foldable structure and soft body mechanical structure
By designing a foldable unit that includes trapezoidal and triangular folding pieces, a stable configuration that remains stable under bending deformation is achieved, solving the problem that existing origami structures cannot maintain stability under bending deformation and expanding the scope of applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TSINGHUA UNIVERSITY
- Filing Date
- 2024-04-30
- Publication Date
- 2026-07-21
Smart Images
Figure CN118404570B_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of mechanical structures, specifically relating to a foldable structure and a soft mechanical structure. Background Technology
[0002] Origami structures are widely used in robotics, aerospace, and other fields due to their advantages such as light weight, high structural strength, and small folded volume. Most existing tubular origami structures can only achieve a certain degree of elongation and cannot achieve a stable configuration under different bending deformations. For specific space applications, there are specific requirements for the tubular structure of the origami structure, necessitating that the tubular structure can achieve a certain degree of bending while maintaining a stable configuration. Summary of the Invention
[0003] The purpose of this application is to provide a foldable structure and a soft mechanical structure, at least to solve the problem in the prior art that foldable structures cannot be bent or cannot maintain a stable configuration after bending.
[0004] In a first aspect, embodiments of this application provide a foldable structure, the foldable structure comprising:
[0005] Multiple folded units arranged along the first direction Z, and the multiple folded units connected to form a hollow tubular structure;
[0006] Each folding unit includes two folding units stacked along the first direction Z, with a first crease formed at the connection between the two folding units, and the two folding units are symmetrically distributed about the plane formed by the first crease.
[0007] Each folding unit includes multiple trapezoidal folding pieces and at least two triangular folding pieces, wherein the number of trapezoidal folding pieces is greater than the number of triangular folding pieces, and the difference between the number of trapezoidal folding pieces and the number of triangular folding pieces is 2;
[0008] A plurality of trapezoidal folded pieces and at least two triangular folded pieces form a tubular structure. At least three of the trapezoidal folded pieces have their lower base edges coplanar. Each pair of adjacent trapezoidal folded pieces is connected by a triangular folded piece or at least one trapezoidal folded piece.
[0009] When the included angle between the two symmetrically distributed trapezoidal folding pieces included in the two folding units of the folding unit changes, the folding unit undergoes expansion, contraction, or bending deformation, wherein the first direction Z is consistent with the expansion and contraction direction of the folding unit.
[0010] Optionally, when the foldable structure shrinks to its minimum size along the first direction Z, the plurality of folding units shrink into a polygonal plate-like structure.
[0011] Optionally, the surface of the polygonal plate structure includes a plurality of trapezoidal shapes and at least two triangular shapes, wherein the number of trapezoidal shapes is greater than the number of triangular shapes, and the difference between the number of trapezoidal shapes and the number of triangular shapes is 2;
[0012] The surface of the polygonal plate structure conforms to the formula for the sum of interior angles of a polygon: (n-2)×180°, where n is the number of sides of the polygonal plate structure. The obtuse interior angle of one of the two adjacent trapezoidal folded pieces and the acute interior angle of the other trapezoidal folded piece are supplementary. The obtuse interior angle of the trapezoidal folded piece and the base angle of the triangle folded piece are supplementary. The acute interior angle of the trapezoidal folded piece and the vertex angle of the triangle folded piece are supplementary. The height of the trapezoidal folded piece and the height of the triangle folded piece are equal.
[0013] Optionally, the foldable structure further includes a drive element;
[0014] The drive unit is connected to the folding unit located at the end in the first direction Z among the plurality of folding units. Under the driving force of the drive unit, the plurality of folding units extend, retract, or bend.
[0015] Optionally, when the included angle between the two symmetrically distributed trapezoidal folding pieces included in the two folding units of the folding unit increases, the length of the folding unit body in the first direction increases;
[0016] Wherein, when the included angle between the two symmetrically distributed trapezoidal folding pieces included in the two folding units of the folding unit increases to 180°, the length of the folding unit body in the first direction Z increases to its maximum value.
[0017] Optionally, if the included angle between the two symmetrically distributed trapezoidal folding pieces included in the two folding units of the folding unit decreases, the length of the folding unit body in the first direction Z decreases;
[0018] Wherein, when the included angle between the two symmetrically distributed trapezoidal folding pieces of the two folding units included in the folding unit decreases to approximately 0°, the length of the folding unit body in the first direction tends to be at its minimum value.
[0019] Optionally, the angle between the two trapezoidal folding pieces symmetrically distributed on the first side of the second direction X of the folding unit body is a first angle, and the angle between the two trapezoidal folding pieces symmetrically distributed on the second side of the second direction X of the folding unit body is a second angle. When the first angle is smaller than the second angle, the folding unit bends toward the first side of the second direction X, and when the second angle is smaller than the first angle, the folding unit bends toward the second side of the second direction X. The second direction X and the first direction Z intersect.
[0020] Optionally, each folded unit includes four of the trapezoidal folding pieces and two of the triangular folding pieces;
[0021] The lower base edges of the three trapezoidal folded pieces and the upper base edge of the other trapezoidal folded piece are arranged on the same plane;
[0022] The top base edges of the three trapezoidal folded pieces, the top base edge of the other trapezoidal folded piece, and the base edges of the three triangular folded pieces are arranged in the same plane;
[0023] The fold between two adjacent folding units is the second crease. The second crease is the outer contour of the polygonal structure formed by the coplanar arrangement of the lower bottom edge of the three trapezoidal folding pieces and the upper bottom edge of the other trapezoidal folding piece.
[0024] The first crease is the outer contour of a polygonal structure formed by the coplanar arrangement of the upper base edges of the three trapezoidal folded pieces, the upper base edge of the other trapezoidal folded piece, and the base edges of the three triangular folded pieces.
[0025] The trapezoidal folded piece is an isosceles trapezoidal sheet structure, the triangular folded piece is an isosceles triangular sheet structure, the degree measure of the two obtuse interior angles of the trapezoidal folded piece is 150°, the degree measure of the two acute interior angles of the trapezoidal folded piece is 30°, the base angle of the triangular folded piece is 30°, and the vertex angle of the triangular folded piece is 120°.
[0026] Optionally, the folding unit is made of an elastic material, which has an elastic modulus of 634 MPa and a Poisson's ratio of 0.3.
[0027] Secondly, embodiments of this application provide a soft mechanical structure, which includes the foldable structure described in any one of the first aspects above;
[0028] The mechanical component is fixed to at least one end of the plurality of folding units in the first direction Z, wherein the mechanical component is a suction cup or a robotic gripper.
[0029] In this embodiment of the invention, since multiple folding units are connected to form a hollow tubular structure, each folding unit includes two folding units stacked along the first direction Z. A first crease is formed at the connection between the two folding units. The two folding units are symmetrically distributed with respect to the plane formed by the first crease. Therefore, under the action of external force, the size and shape of the folding unit in the first direction Z can be changed through the first crease formed between the two folding units.
[0030] Furthermore, since each folding unit includes multiple trapezoidal folding pieces and at least two triangular folding pieces, the number of trapezoidal folding pieces is greater than the number of triangular folding pieces, and the difference between the number of trapezoidal folding pieces and the number of triangular folding pieces is 2. The multiple trapezoidal folding pieces and at least two triangular folding pieces form a tubular structure. The lower base edges of at least three of the multiple trapezoidal folding pieces are coplanar, and each pair of adjacent trapezoidal folding pieces is connected by a triangular folding piece or at least one trapezoidal folding piece. Therefore, creases can be formed at the connection points between adjacent trapezoidal folding pieces in each folding unit, and creases can be formed at the connection points between adjacent trapezoidal folding pieces and triangular folding pieces in each folding unit. This allows support edges and stress concentration edges to be formed at the creases between each folding unit. Thus, after the external force is removed, each folding unit can maintain its size and shape after folding under the support of the support edges and stress concentration edges formed at the creases.
[0031] In summary, since the folding unit undergoes expansion or bending deformation when the included angle between the two symmetrically distributed trapezoidal folding pieces in the two folding units of the folding unit changes, the foldable structure in the embodiments of the present invention can both extend and shorten, and can also bend and deform. After extension, shortening or bending deformation, the foldable structure can maintain a stable configuration after folding, thereby broadening the application range of the foldable structure and making its use scenarios unrestricted. Attached Figure Description
[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0033] Figure 1 This is a schematic diagram showing the structure of a foldable structure provided in this application in its extended state.
[0034] Figure 2This is a schematic diagram showing the structure of a foldable structure provided in this application embodiment, including a folding unit in an extended state;
[0035] Figure 3 This is a schematic diagram illustrating the structure of a foldable structure provided in this application embodiment in a bent state;
[0036] Figure 4 This is a schematic diagram showing the structure of a foldable structure provided in this application embodiment, including a folding unit in a bent state;
[0037] Figure 5 This is a schematic diagram of a foldable structure provided in an embodiment of this application in its fully collapsed state;
[0038] Figure 6 This is a schematic diagram illustrating the structure of a soft mechanical structure provided in this application under a bending state.
[0039] Figure 7 This is a schematic diagram illustrating the structure of a soft mechanical structure provided in an embodiment of this application in an elongated state;
[0040] Figure 8 This is a schematic diagram showing the structure of another soft mechanical structure provided in this application embodiment in a bent state;
[0041] Figure 9 This is a schematic diagram showing another soft mechanical structure provided in the embodiments of this application in an elongated state.
[0042] Figure label:
[0043] 1: Foldable structure; 2: Mechanical component; 10: Folding unit; 101: Folding unit; 1011: Trapezoidal folding piece; 1012: Triangular folding piece. Detailed Implementation
[0044] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.
[0045] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0046] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0047] In a first aspect, embodiments of the present invention provide a foldable structure, such as Figures 1 to 5 As shown, the foldable structure includes:
[0048] Multiple folding units 10 are arranged along the first direction Z, and the multiple folding units 10 are connected to form a hollow tubular structure.
[0049] Each folding unit 10 includes two folding units 101 stacked along a first direction Z. A first crease is formed at the connection between the two folding units 101, and the two folding units 101 are symmetrically distributed about the plane formed by the first crease.
[0050] Each folded unit 101 includes a plurality of trapezoidal folded pieces 1011 and at least two triangular folded pieces 1012, wherein the number of trapezoidal folded pieces 1011 is greater than the number of triangular folded pieces 1012, and the difference between the number of trapezoidal folded pieces 1011 and the number of triangular folded pieces 1012 is 2.
[0051] Multiple trapezoidal folded pieces 1011 and at least two triangular folded pieces 1012 form a tubular structure. At least three of the trapezoidal folded pieces 1011 have their lower base edges coplanar. Each pair of adjacent trapezoidal folded pieces 1011 is connected by a triangular folded piece 1012 or at least one trapezoidal folded piece 1011.
[0052] When the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 changes, the folding unit 10 undergoes expansion, contraction or bending deformation, wherein the first direction Z is consistent with the expansion and contraction direction of the folding unit 10.
[0053] As can be seen from the above embodiments, in the embodiments of the present invention, since multiple folding units 10 are connected to form a hollow tubular structure, each folding unit 10 includes two folding single units 101 stacked along the first direction Z. A first crease is formed at the connection of the two folding single units 101. The two folding single units 101 are symmetrically distributed with respect to the plane formed by the first crease. Therefore, under the action of external force, the size and shape of the folding unit 10 in the first direction Z can be changed through the first crease formed between the two folding single units 101.
[0054] Furthermore, since each folded unit 101 includes multiple trapezoidal folded pieces 1011 and at least two triangular folded pieces 1012, the number of trapezoidal folded pieces 1011 is greater than the number of triangular folded pieces 1012, and the difference between the number of trapezoidal folded pieces 1011 and the number of triangular folded pieces 1012 is 2, the multiple trapezoidal folded pieces 1011 and at least two triangular folded pieces 1012 form a tubular structure, at least three of the multiple trapezoidal folded pieces 1011 have their lower base edges coplanar, and among the at least three trapezoidal folded pieces 1011 with their lower base edges coplanar, every two adjacent trapezoidal folded pieces 1011... A triangular folding piece 1012 or at least a trapezoidal folding piece 1011 is connected between each folding unit 101. Therefore, a crease can be formed at the connection between two adjacent trapezoidal folding pieces 1011 in each folding unit 101. A crease can also be formed at the connection between adjacent trapezoidal folding pieces 1011 and triangular folding pieces 1012 in each folding unit 101. This allows support edges and stress concentration edges to be formed at the creases between each folding unit 10. After the external force is removed, each folding unit 10 can maintain its size and shape after folding under the support of the support edges and stress concentration edges formed at the creases.
[0055] In summary, since the folding unit 10 undergoes expansion or bending deformation when the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 of the two folding units 101 included in the folding unit 10 changes, the foldable structure in the embodiment of the present invention can both extend and shorten, and can also bend and deform. After extension, shortening or bending deformation, the foldable structure can maintain a stable configuration after folding, thereby broadening the application range of the foldable structure and making the application scenarios of the foldable structure unrestricted.
[0056] In the above embodiments, the number of folding units 10 can be either even or odd. The number of folding units 10 is determined based on the required extension and bending dimensions of the foldable structure, and this embodiment of the invention does not impose any limitation on this. That is, the number of folding units 10 is directly proportional to the required extension and bending dimensions of the foldable structure, and the number of folding units 10 is directly proportional to the required bending dimensions of the foldable structure. In other words, the larger the required extension dimension and the larger the bending angle of the foldable structure, the more folding units 10 are required. Multiple folding units 10 are stacked along the first direction Z, thus forming a tubular structure extending along the first direction Z. This tubular structure is hollow, allowing other devices to be arranged inside the foldable structure.
[0057] Each folding unit 10 has a consistent shape and size. Each folding unit 10 includes two folding single units 101 stacked along the first direction Z. The two folding single units 101 are symmetrically distributed on the plane formed by the first fold crease. That is, the folding units 10 on both sides of the plane formed by the first fold crease have the same shape and structure. Specifically, each folding single unit 101 includes a plurality of trapezoidal folding pieces 1011 and at least two triangular folding pieces 1012. For example, each folding single unit 101 may include four trapezoidal folding pieces 1011 and two triangular folding pieces 1012. Alternatively, each folding single unit 101 may include six trapezoidal folding pieces 1011 and four triangular folding pieces 1012. The number of trapezoidal folding pieces 1011 in each folding single unit 101 only needs to be two more than the number of triangular folding pieces 1012. This embodiment of the invention does not limit this.
[0058] Furthermore, a plurality of trapezoidal folded pieces 1011 and at least two triangular folded pieces 1012 form a tubular structure. At least three of the trapezoidal folded pieces 1011 have their lower base edges coplanar, such that the plane formed by the lower base edges of at least three of the trapezoidal folded pieces 1011 forms one end face of the folded unit 101. The upper base edges of the remaining trapezoidal folded pieces 1011 and the base edges of the at least two triangles form the other end face of the folded unit 101. Each pair of adjacent trapezoidal folded pieces 1011 with their lower base edges coplanar is connected by a triangular folded piece 1012 or at least one trapezoidal folded piece 1011. That is, each pair of adjacent trapezoidal folded pieces 1011 with the same lower base edge orientation is either adjacent through a trapezoidal folded piece 1011 with the opposite lower base edge orientation or connected through a triangular folded piece 1011. In this way, the two non-coplanar trapezoidal folded pieces 1011 support and interact with each other through one trapezoidal folded piece 1011 or one triangular folded piece 1012. Supporting edges and stress concentration edges are formed by the waist edges of the trapezoidal folded piece 1011 and the triangular folded piece 1012. Therefore, after the external force is removed, each folding unit 10 can maintain its size and shape after folding due to the support of the supporting edges and stress concentration edges formed at the creases. In this embodiment, the upper base edge is the shorter of the two parallel base edges of the trapezoidal folded piece 1011, and the lower base edge is the longer of the two parallel base edges of the trapezoidal folded piece 1011.
[0059] It should be noted that, according to Figure 1 In this embodiment of the invention, the X-axis and Z-axis intersect. For ease of explanation, the first direction is defined as the Z-axis direction, and the second direction is defined as the X-axis direction. Further explanation: the definition of perpendicularity in the specification should be understood as perpendicular if it fluctuates by 10% within 90 degrees; that is, the angle between the defined first and second directions should be understood as perpendicular if it is between 80 and 90 degrees.
[0060] The structure of the embodiments of the present invention in various forms will be described in detail below:
[0061] In some embodiments, such as Figure 5 As shown, when the foldable structure is contracted to its minimum size along the first direction Z, the multiple folding units 10 contract into a polygonal plate-like structure. This allows the foldable structure to form a polygonal plate-like structure, which can then be contracted into a polygonal plate-like structure in the non-working state, facilitating the storage and folding of the foldable structure and reducing the space occupied by the foldable structure in the non-working state.
[0062] For the polygonal plate structure in the above embodiments, in some embodiments, the surface of the polygonal plate structure includes multiple trapezoidal shapes and at least two triangular shapes, the number of trapezoidal shapes is greater than the number of triangular shapes, and the difference between the number of trapezoidal shapes and the number of triangular shapes is 2; the surface of the polygonal plate structure conforms to the polygon interior angle sum formula: (n-2)×180°, where n is the number of sides of the polygonal plate structure, the obtuse interior angle of one trapezoidal folding piece 1011 and the acute interior angle of the other trapezoidal folding piece 1011 are complementary, the obtuse interior angle of the trapezoidal folding piece 1011 and the base angle of the triangular folding piece 1012 of the adjacent trapezoidal folding piece 1011 and the triangular folding piece 1012 are complementary, the acute interior angle of the trapezoidal folding piece 1011 and the vertex angle of the triangular folding piece 1012 of the adjacent trapezoidal folding piece 1011 and the triangular folding piece 1012 are complementary, and the height of the trapezoidal folding piece 1011 and the height of the triangular folding piece 1012 are equal.
[0063] It should be noted that, in the above embodiments, the polygonal plate-like structure formed by folding includes at least three trapezoidal folding pieces 1011 located on the first layer plane, and the remaining trapezoidal folding pieces 1011 and triangular folding pieces 1012 located on the second layer plane. The first layer plane and the second layer plane are stacked together to form the surface of the polygonal plate-like structure. The surface includes multiple trapezoidal shapes and at least two triangular shapes, with a triangular shape or trapezoidal shape disposed between each two adjacent trapezoidal shapes. Thus, when the surface of the polygonal plate structure conforms to the formula for the sum of interior angles of a polygon: (n-2)×180°, the obtuse interior angle of one of the two adjacent trapezoidal folded pieces 1011 and the acute interior angle of the other trapezoidal folded piece 1011 are complementary, the obtuse interior angle of the trapezoidal folded piece 1011 and the base angle of the triangular folded piece 1012 are complementary, the acute interior angle of the trapezoidal folded piece 1011 and the vertex angle of the triangular folded piece 1012 are complementary, and the height of the trapezoidal folded piece 1011 and the height of the triangular folded piece 1012 are equal, each folded unit 101 can be completely folded to form a polygonal plate structure. In the above embodiment, the height of the trapezoidal folding piece 1011 is shown as h1 in the figure, the height of the triangular folding piece 1012 in the above embodiment is shown as h2 in the figure, the obtuse interior angle of the trapezoidal folding piece 1011 in the above embodiment is shown as ∠1 in the figure, the acute interior angle of the trapezoidal folding piece 1011 in the above embodiment is shown as ∠2 in the figure, the base angle of the triangular folding piece 1012 in the above embodiment is shown as ∠3 in the figure, and the apex angle of the triangular folding piece 1012 in the above embodiment is shown as ∠4 in the figure.
[0064] In one possible implementation, such as Figure 1 As shown, when the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 increases, the length of the folding unit 10 body in the first direction increases; wherein, when the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 increases to 180°, the length of the folding unit 10 body in the first direction Z increases to its maximum value.
[0065] In this embodiment, when the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 increases, the distance between the end faces formed by the coplanar lower base edges of at least three trapezoidal folding pieces 1011 in two adjacent folding units 101 increases, that is, the size of each folding unit 10 in the first direction Z increases. This allows the foldable structure to be applied to application scenarios requiring elongation and increased size in the first direction Z. Furthermore, when the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 increases to 180°, the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 are coplanar in the first direction Z, and the two symmetrically distributed triangles included in the two folding units 101 of the folding unit 10 are coplanar in the first direction Z, thereby increasing the length of the folding unit body in the first direction Z to its maximum value.
[0066] It should be noted that the above description only takes the case where the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 increases as an example. When the length of the folding unit 10 increases in the first direction Z, the included angle between the two symmetrically distributed triangular folding pieces 1012 included in the two folding units 101 of the folding unit 10 also increases accordingly. This will not be elaborated further in the embodiments of the present invention.
[0067] In one possible implementation, such as Figure 5 As shown, when the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 decreases, the length of the folding unit 10 body in the first direction Z decreases; wherein, when the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 decreases to approximately 0°, the length of the folding unit 10 body in the first direction approaches its minimum value.
[0068] In this embodiment, when the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 decreases, the distance between the end faces formed by the coplanar lower base edges of at least three trapezoidal folding pieces 1011 in two adjacent folding units 101 decreases, that is, the size of each folding unit 10 in the first direction Z decreases. This allows the foldable structure to be applied to application scenarios requiring expansion and contraction to reduce the size of the foldable structure in the first direction Z. Furthermore, when the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 decreases, the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 tend to be arranged nearly parallel (i.e., tend to be stacked) in the first direction Z, making the length of the folding unit 10 body in the first direction approach its minimum value. Because there is a crease between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10, and the trapezoidal folding pieces 1011 have a thickness, the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 cannot reach 0°, but can only approach 0°.
[0069] It should be noted that the above description only takes the case where the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 decreases as an example. When the length of the folding unit 10 body in the first direction Z decreases, the included angle between the two symmetrically distributed triangular folding pieces 1012 included in the two folding units 101 of the folding unit 10 also decreases accordingly. This will not be elaborated further in the embodiments of the present invention.
[0070] In another possible implementation, such as Figure 3 and Figure 4 As shown, the folding unit 10 includes two folding units 101, and the included angle between the two trapezoidal folding pieces 1011 symmetrically distributed on the first side of the second direction X is a first included angle. The included angle between the two folding units 101 and the two trapezoidal folding pieces 1011 symmetrically distributed on the second side of the second direction X is a second included angle. When the first included angle is smaller than the second included angle, the folding unit 10 bends towards the first side of the second direction X. When the second included angle is smaller than the first included angle, the folding unit 10 bends towards the second side of the second direction X. The second direction X and the first direction Z intersect. Thus, in this embodiment, the foldable structure can be applied to application scenarios that require bending deformation.
[0071] It should be noted that during the bending process, as the included angle between the two trapezoidal folding pieces 1011 symmetrically distributed on the second side of the second direction X of the two folding units 101 included in the bending side of the folding unit 10 gradually decreases, that is, the size of the shape formed by the two trapezoidal folding pieces 1011 symmetrically distributed on the second side of the second direction X of the two folding units 101 included in the bending side of the folding unit 10 gradually shrinks, while the included angle between the two trapezoidal folding pieces 1011 symmetrically distributed on the first side of the second direction X of the two folding units 101 included in the bending side of the folding unit 10 gradually increases, that is, the size of the shape formed by the two trapezoidal folding pieces 1011 symmetrically distributed on the first side of the second direction X of the two folding units 101 included in the bending side of the folding unit 10 gradually elongates, thereby causing the multiple folding units 10 connected to form a hollow tubular structure to bend to one side, forming a bending deformation. Furthermore, it should be noted that the above description only takes the case of bending deformation caused by the change of the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 included in the two folding units 101 of the folding unit 10 as an example. During the bending deformation process, the included angle between the two symmetrically distributed triangular folding pieces 1012 included in the two folding units 101 of the folding unit 10 also changes accordingly. That is, the foldable structure can be bent and deformed in any direction intersecting the first direction Z, thereby increasing the bending deformation range of the foldable structure.
[0072] In some exemplary embodiments, each folding unit 101 includes four trapezoidal folding pieces 1011 and two triangular folding pieces 1012; the lower base edges of three trapezoidal folding pieces 1011 and the upper base edge of another trapezoidal folding piece 1011 are coplanar; the upper base edges of three trapezoidal folding pieces 1011, the upper base edge of another trapezoidal folding piece 1011, and the base edges of three triangular folding pieces 1012 are coplanar; wherein, the fold between two adjacent folding units 10 is a second crease, the second crease being the outer contour of a polygonal structure formed after the lower base edges of three trapezoidal folding pieces 1011 and the upper base edge of another trapezoidal folding piece 1011 are coplanar; the first crease is the outer contour of a polygonal structure formed after the upper base edges of three trapezoidal folding pieces 1011, the upper base edge of another trapezoidal folding piece 1011, and the base edges of three triangular folding pieces 1012 are coplanar.
[0073] It should be noted that, in this embodiment, since each folding unit 101 includes four trapezoidal folding pieces 1011 and two triangular folding pieces 1012, the lower base edges of three trapezoidal folding pieces 1011 and the upper base edge of another trapezoidal folding piece 1011 are coplanar, and the upper base edges of three trapezoidal folding pieces 1011, the upper base edge of another trapezoidal folding piece 1011 and the base edges of three triangular folding pieces 1012 are coplanar, the creases between each folding unit 101 are all inclined edges (the waist edge of the triangular folding piece 1012 and the waist edge of the trapezoidal folding piece 1011), and the number of creases is 6, which is more conducive to the distribution of the supporting edges and stress concentration edges formed by the inclined edges around the axis of the hollow tubular structure formed by the connection of multiple folding units 10. Furthermore, the fold between two adjacent folding units 10 forms a second crease. The second crease is the outer contour of a polygonal structure formed by the coplanar arrangement of the lower base edges of three trapezoidal folding pieces 1011 and the upper base edge of another trapezoidal folding piece 1011. The second crease comprises four creases. The first crease is the outer contour of a polygonal structure formed by the coplanar arrangement of the upper base edges of three trapezoidal folding pieces 1011, the upper base edge of another trapezoidal folding piece 1011, and the base edges of three trapezoidal folding pieces 1011. The first crease also comprises four creases. Thus, regardless of whether folding is done through the first crease or the second crease, the hollow tubular structure formed by connecting multiple folding units 10 can be bent and deformed in at least four directions along its axis.
[0074] In the above embodiments, the trapezoidal folded piece 1011 is an isosceles trapezoidal sheet structure, and the triangular folded piece 1012 is an isosceles triangular sheet structure.
[0075] Thus, since the trapezoidal folding piece 1011 is an isosceles trapezoidal sheet structure and the triangular folding piece 1012 is an isosceles triangular sheet structure, the foldable structure, when contracted into a polygonal plate structure, more easily satisfies the condition that the surface of the polygonal plate structure conforms to the polygonal interior angle sum formula: (n-2)×180°. The obtuse interior angle of one of the two adjacent trapezoidal folding pieces 1011 and the acute interior angle of the other trapezoidal folding piece 1011 are complementary. The obtuse interior angle of the trapezoidal folding piece 1011 and the base angle of the triangular folding piece 1012 are complementary. The acute interior angle of the trapezoidal folding piece 1011 and the vertex angle of the triangular folding piece 1012 are complementary. The height of the trapezoidal folding piece 1011 and the height of the triangular folding piece 1012 are equal. This makes it easier for each folding unit 101 to be completely folded to form a polygonal plate structure. Furthermore, since the trapezoidal folding piece 1011 is an isosceles trapezoidal sheet structure and the triangular folding piece 1012 is an isosceles triangular sheet structure, both the trapezoidal folding piece 1011 and the triangular folding piece 1012 are regular sheet structures, which is more conducive to the manufacturing and processing of a single folding unit 10 and helps to reduce costs.
[0076] Furthermore, regarding the specific structures of the trapezoidal folding piece 1011 and the triangular folding piece 1012, in some exemplary embodiments, the degree measure of the two obtuse interior angles of the trapezoidal folding piece 1011 is 150°, the degree measure of the two acute interior angles of the trapezoidal folding piece 1011 is 30°, the base angle of the triangular folding piece 1012 is 30°, and the apex angle of the triangular folding piece 1012 is 120°. This allows the degree of the lower base of the trapezoidal folding piece 1011 to be equal to the degree of the upper base and the height of the trapezoidal folding piece 1011. The sum of these two times makes the base of the triangular folded piece 1012 equal to the height of the triangular folded piece 1012. This makes the length of the waist side of the triangular folding piece 1012 and the length of the waist side of the isosceles triangle equal to twice the height of the triangular folding piece 1012. In this way, the height of each folding unit 101 is proportional to the sides of the triangular folding piece 1012 and the sides of the trapezoidal folding piece 1011, which is more conducive to precisely controlling the length of the foldable structure's extension and retraction.
[0077] Optionally, in some embodiments, the foldable structure further includes a driving member; the driving member is connected to the folding unit 10 located at the end in the first direction Z among the plurality of folding units 10, and the plurality of folding units 10 extend, retract or bend under the driving force of the driving member.
[0078] It should be noted that the driving component can be a cylinder, motor or other device with driving force, which can generate external force on multiple folding units 10 so that the multiple folding units 10 can extend, retract or bend.
[0079] Regarding the material of the folding unit 10 in the embodiments of the present invention, in some embodiments, the material of the folding unit 10 is an elastic material, which is a material with an elastic modulus of 634 MPa and a Poisson's ratio of 0.3.
[0080] It should be noted that the elastic material can be craft paper, silicone, plastic, or thermoplastic polyurethane elastomer rubber, etc., and the embodiments of the present invention are not limited to this. In this way, not only can the foldable structure achieve multi-angle bending and maintain a stable configuration after folding, but it can also enhance the deformation capacity of the foldable structure, making it convenient for processing, manufacturing, and use.
[0081] In this embodiment of the invention, since multiple folding units 10 are connected to form a hollow tubular structure, each folding unit 10 includes two folding single units 101 stacked along the first direction Z. A first crease is formed at the connection between the two folding single units 101. The two folding single units 101 are symmetrically distributed with respect to the plane formed by the first crease. Therefore, under the action of external force, the size and shape of the folding unit 10 in the first direction Z can be changed through the first crease formed between the two folding single units 101.
[0082] Furthermore, since each folded unit 101 includes multiple trapezoidal folded pieces 1011 and at least two triangular folded pieces 1012, the number of trapezoidal folded pieces 1011 is greater than the number of triangular folded pieces 1012, and the difference between the number of trapezoidal folded pieces 1011 and the number of triangular folded pieces 1012 is 2, the multiple trapezoidal folded pieces 1011 and at least two triangular folded pieces 1012 form a tubular structure, at least three of the multiple trapezoidal folded pieces 1011 have their lower base edges coplanar, and among the at least three trapezoidal folded pieces 1011 with their lower base edges coplanar, every two adjacent trapezoidal folded pieces 1011... A triangular folding piece 1012 or at least a trapezoidal folding piece 1011 is connected between 011, so that a crease can be formed at the connection between two adjacent trapezoidal folding pieces 1011 in each folding unit 101, and a crease can be formed at the connection between adjacent trapezoidal folding pieces 1011 and triangular folding pieces 1012 in each folding unit 101, so that a support edge and a stress concentration edge can be formed at the crease between each folding unit 10, and after the external force is removed, each folding unit 10 can maintain its size and shape after folding under the support of the support edge and stress concentration edge formed at the crease.
[0083] In summary, since the folding unit 10 undergoes expansion or bending deformation when the included angle between the two symmetrically distributed trapezoidal folding pieces 1011 of the two folding units 101 included in the folding unit 10 changes, the foldable structure in the embodiment of the present invention can both extend and shorten, and can also bend and deform. After extension, shortening or bending deformation, the foldable structure can maintain a stable configuration after folding, thereby broadening the application range of the foldable structure and making the application scenarios of the foldable structure unrestricted.
[0084] Secondly, such as Figures 6 to 9 As shown, this embodiment of the invention also provides a soft mechanical structure, which includes mechanical components and a foldable structure as described in any embodiment of the first aspect; the mechanical components are fixed to at least one end of a plurality of folding units 10 in a first direction Z.
[0085] It should be noted that, since the soft mechanical structure includes mechanical components and the foldable structure described in any embodiment of the first aspect, with the mechanical components fixed to at least one end of the plurality of folding units 10 in the first direction Z, the foldable structure can both extend and shorten, and can also bend and deform. Furthermore, after extension, shortening, or bending deformation, the foldable structure can maintain a stable configuration after folding. This allows the soft mechanical structure to achieve flexible deformability, possessing advantages such as large bending degree, negative Poisson's ratio, large fold-to-spread ratio, and multi-steady-state performance, thus making its application scenarios unrestricted. In addition, the soft mechanical structure can be a robot manipulator, flexible solar wing deployment and support, space sunshade, etc. The embodiments of this invention do not limit this; while solving the turning problem of the soft mechanical structure, it can also solve the spatial accommodation problem of the soft mechanical structure.
[0086] Optionally, in some embodiments, the mechanical component is a suction cup or a robotic gripper. It should be noted that the suction cup or robotic gripper is connected to at least one end of multiple folding units 10 in the first direction Z via a mounting structure such as a connecting plate or mounting block, and then the suction cup or robotic gripper is detachably connected to the structure to facilitate replacement of the suction cup or robotic gripper, so that the same foldable structure can be applied to different mechanical components.
[0087] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0088] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.
Claims
1. A foldable structure, characterized in that, The foldable structure includes: Multiple folded units arranged along the first direction Z, and the multiple folded units connected to form a hollow tubular structure; Each folding unit includes two folding units stacked along the first direction Z, with a first crease formed at the connection between the two folding units, and the two folding units are symmetrically distributed about the plane formed by the first crease. Each folding unit includes multiple trapezoidal folding pieces and at least two triangular folding pieces, wherein the number of trapezoidal folding pieces is greater than the number of triangular folding pieces, and the difference between the number of trapezoidal folding pieces and the number of triangular folding pieces is 2; A plurality of trapezoidal folded pieces and at least two triangular folded pieces form a tubular structure. At least three of the trapezoidal folded pieces have their lower base edges coplanar. Each pair of adjacent trapezoidal folded pieces is connected by a triangular folded piece or at least one trapezoidal folded piece. When the included angle between the two symmetrically distributed trapezoidal folding pieces included in the two folding units of the folding unit changes, the folding unit undergoes expansion, contraction, or bending deformation, wherein the first direction Z is consistent with the expansion and contraction direction of the folding unit.
2. The foldable structure according to claim 1, characterized in that, When the foldable structure shrinks to its minimum size along the first direction Z, the plurality of folding units shrink into a polygonal plate-like structure.
3. The foldable structure according to claim 2, characterized in that, The surface of the polygonal plate structure includes multiple trapezoidal shapes and at least two triangular shapes, wherein the number of trapezoidal shapes is greater than the number of triangular shapes, and the difference between the number of trapezoidal shapes and the number of triangular shapes is 2; The surface of the polygonal plate structure conforms to the formula for the sum of interior angles of a polygon: (n-2)×180°, where n is the number of sides of the polygonal plate structure. The obtuse interior angle of one of the two adjacent trapezoidal folded pieces and the acute interior angle of the other trapezoidal folded piece are supplementary. The obtuse interior angle of the trapezoidal folded piece and the base angle of the triangle folded piece are supplementary. The acute interior angle of the trapezoidal folded piece and the vertex angle of the triangle folded piece are supplementary. The height of the trapezoidal folded piece and the height of the triangle folded piece are equal.
4. The foldable structure according to claim 1, characterized in that, The foldable structure also includes a drive component; The drive unit is connected to the folding unit located at the end in the first direction Z among the plurality of folding units. Under the driving force of the drive unit, the plurality of folding units extend, retract, or bend.
5. The foldable structure according to claim 1, characterized in that, When the included angle between the two symmetrically distributed trapezoidal folding pieces included in the two folding units of the folding unit increases, the length of the folding unit body in the first direction increases; Wherein, when the included angle between the two symmetrically distributed trapezoidal folding pieces included in the two folding units of the folding unit increases to 180°, the length of the folding unit body in the first direction Z increases to its maximum value.
6. The foldable structure according to claim 1, characterized in that, When the included angle between the two symmetrically distributed trapezoidal folding pieces included in the two folding units of the folding unit decreases, the length of the folding unit body in the first direction Z decreases; Wherein, when the included angle between the two symmetrically distributed trapezoidal folding pieces of the two folding units included in the folding unit decreases to approximately 0°, the length of the folding unit body in the first direction tends to be at its minimum value.
7. The foldable structure according to claim 1, characterized in that, The angle between the two trapezoidal folding pieces symmetrically distributed on the first side of the second direction X of the folding unit body is a first angle, and the angle between the two trapezoidal folding pieces symmetrically distributed on the second side of the second direction X of the folding unit body is a second angle. When the first angle is smaller than the second angle, the folding unit bends toward the first side of the second direction X. When the second angle is smaller than the first angle, the folding unit bends toward the second side of the second direction X. The second direction X and the first direction Z intersect.
8. The foldable structure according to claim 1, characterized in that, Each folded unit includes four of the said trapezoidal folding pieces and two of the said triangular folding pieces; The lower base edges of the three trapezoidal folded pieces and the upper base edge of the other trapezoidal folded piece are arranged on the same plane; The top base edges of the three trapezoidal folded pieces, the top base edge of the other trapezoidal folded piece, and the base edges of the three triangular folded pieces are arranged in the same plane; The fold between two adjacent folding units is the second crease. The second crease is the outer contour of the polygonal structure formed by the coplanar arrangement of the lower bottom edge of the three trapezoidal folding pieces and the upper bottom edge of the other trapezoidal folding piece. The first crease is the outer contour of a polygonal structure formed by the coplanar arrangement of the upper base edges of the three trapezoidal folded pieces, the upper base edge of the other trapezoidal folded piece, and the base edges of the three triangular folded pieces. The trapezoidal folded piece is an isosceles trapezoidal sheet structure, the triangular folded piece is an isosceles triangular sheet structure, the degree measure of the two obtuse interior angles of the trapezoidal folded piece is 150°, the degree measure of the two acute interior angles of the trapezoidal folded piece is 30°, the base angle of the triangular folded piece is 30°, and the vertex angle of the triangular folded piece is 120°.
9. The foldable structure according to claim 1, characterized in that, The folding unit is made of an elastic material with an elastic modulus of 634 MPa and a Poisson's ratio of 0.
3.
10. A soft mechanical structure, characterized in that, The soft mechanical structure includes mechanical components and the foldable structure according to any one of claims 1 to 9; The mechanical component is fixed to at least one end of the plurality of folding units in the first direction Z, wherein the mechanical component is a suction cup or a robotic gripper.