Single-degree-of-freedom folding and unfolding mechanism for the transformation between regular hexagon in plane and octadecahedron in space

Abstract

The present invention discloses a single-degree-of-freedom folding and unfolding mechanism for converting a plane regular hexagon to a space tetradecahedron, belonging to the field of mechanism application technology. The mechanism comprises a derived regular hexagonal frame, a cylindrical connecting rod, a bent rod, a hollow arc-shaped moving pair, a solid arc-shaped moving pair, a type I semi-cylindrical connecting rod, and a type II semi-cylindrical connecting rod. The bent rod has an angle of 60 degrees, and the angles of the arc-shaped moving pairs are both 60 degrees. The type I semi-cylindrical connecting rod and the type II semi-cylindrical connecting rod can converge to form a cylinder. Two type II semi-cylindrical connecting rods are connected by a hollow arc-shaped moving pair and a solid arc-shaped moving pair. The type II semi-cylindrical connecting rods can converge to form a cylinder. The present invention drives the folding and unfolding of the entire mechanism through the revolute pair of the connecting rod I, and finally fully closes to form a spatial polyhedron. The mechanism can realize the conversion from a plane geometric body to a spatial geometric body. The mechanism can be applied to small and medium-sized folding and unfolding antennas, envelope capture of objects in space exploration, and docking of space stations.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanism application, and in particular relates to a single-degree-of-freedom folding and unfolding mechanism capable of realizing conversion between a plane regular hexagon and a space tetraoctadecahedron. Background Art

[0002] Spatial foldable mechanisms have the ability to fold from a collapsed state into a predetermined configuration, offering advantages such as high rigidity, high reliability, and high stability. With the development of the aerospace industry, their applications are becoming increasingly widespread. In recent years, spatial foldable mechanisms have developed towards modularity, with multi-ring foldable mechanisms gaining popularity due to their excellent performance. However, due to dimensional constraints, their folding performance is limited. Existing multi-ring foldable mechanisms have relatively limited functionality, with few capable of switching between a planar truss mode and a polyhedron mode. Therefore, a new technical solution is urgently needed to address this problem. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a single-degree-of-freedom multi-ring spatial foldable mechanism, which can be fully unfolded to form a planar regular hexagonal configuration, or completely closed to form a spatial tetraoctadecahedron configuration through the connection and movement of the revolving pair, and the mechanism is easy to control during the shape conversion process.

[0004] A single-degree-of-freedom folding and unfolding mechanism capable of realizing conversion between a plane regular hexagon and a spatial tetraoctadecahedron is characterized by comprising a derived regular hexagonal frame, a type I connecting rod, a type II connecting rod, a bent rod with an angle of 60 degrees, a hollow arc-shaped moving pair I with an angle of 60 degrees, a solid arc-shaped moving pair II with an angle of 60 degrees, a type I semi-cylindrical connecting rod, and a type II semi-cylindrical connecting rod, wherein each semi-cylindrical connecting rod has a revolute pair on the side close to the cylinder.

[0005] The middle of the frame is a circular base, from which six branch connecting rods extend. They are arranged in a completely symmetrical manner, and the angle between each two connecting rods is 60 degrees.

[0006] There are six I-type connecting rods, one end of which is hinged to the connecting rod of the frame through a rotating pair, the connecting rod is parallel to the connecting rod of the frame, and the other end is hinged to the II-type connecting rod through a rotating pair.

[0007] There are twelve Type II connecting rods, and every two Type II connecting rods are hingedly connected to the same Type I connecting rod through a revolute pair. The angle between the connecting rods is 120 degrees, and their axes coincide with each other. The rods do not interfere with each other, and the other end is hingedly connected to the bent rod through a revolute pair.

[0008] There are six bent rods with an included angle of 60 degrees. There is a cylindrical revolute pair at the vertex of the bent rod, where the geometric center of the cylinder is located at the vertex of the bent rod. The two ends of the bent rod are respectively hingedly connected to two II-type connecting rods connected to different I-type connecting rods through a revolute pair. The revolute pair at the vertex of the bent rod is hingedly connected to the revolute pair of the I-type semi-cylindrical connecting rod.

[0009] There are twelve I-shaped semi-cylindrical connecting rods, and every two connecting rods are hingedly connected to a bent rod through a revolute pair. The rectangular cross-sections of the connecting rods are located on the outside, and the rectangular cross-sections of every two adjacent semi-cylindrical connecting rods are coplanar.

[0010] There are twelve Type II semi-cylindrical connecting rods, each with a revolute joint at one end and a curved boss with an arcuate groove at the other. The boss and the arcuate groove are both at a 60-degree angle and share a common axis. The Type II connecting rods are hingedly connected to the Type I semi-cylindrical connecting rods via a revolute joint, with their rectangular cross-sections coplanar. The angle between two adjacent Type II semi-cylindrical connecting rods is 120 degrees.

[0011] The hollow arc-shaped moving pair I is fixedly connected to the type II semi-cylindrical connecting rod, the arc surfaces between the two are tangent, the axes coincide, and the rectangular section of one side of the arc-shaped pair coincides with the rectangular section of the semi-cylinder.

[0012] The solid arc-shaped moving pair II is fixedly connected to the II-type semi-cylindrical connecting rod, and the rectangular cross section of one side of the arc-shaped moving pair coincides with the rectangular cross section of the semi-cylinder. The arc-shaped moving pair II is tangent to the arc surface of the arc-shaped moving pair I, and the axes coincide.

[0013] The present invention contains twelve rhombus single rings, with angles of 60 degrees and 120 degrees respectively. There are 12 symmetry planes in total, and there are six layers of connecting rod nodes from the inside to the outside. Among them, the center point A of the rotating joint of the I-type connecting rod is i Located on a circle with the geometric center point o of the frame as the center and R1 as the radius, the center point of the rotating joint B i Located on a circle with a radius of R2; the center point C of the revolute joint of the II-type connecting rod i Located on a circle with radius R3; the center point of the rotating joint at the top of the bending rod is D i Located on a circle with radius R4; the rotation center E of the hollow arc motion pair I and the solid arc motion pair II i Located on a circle with radius R5.

[0014] Through the above-mentioned design scheme, the present invention can achieve the following beneficial effects: a single-degree-of-freedom folding and unfolding mechanism capable of converting a planar regular hexagon to a spatial tetraoctadecahedron, driven by the revolute pair of connecting rod I to achieve folding and unfolding of the entire mechanism, ultimately fully closing to form a spatial polyhedron. The mechanism exhibits good enveloping properties during folding and unfolding, and is easy to control during the folding and unfolding process. A novel deployable unit containing a coupling rod and its derived spatial deployable mechanism have high rigidity, high reliability, and high operability, can achieve conversion from a planar geometric body to a spatial geometric body, and can be applied to small and medium-sized folding and unfolding antennas, envelope capture of objects in space exploration, and docking with space stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0016] Figure 1 The figure is a schematic diagram of a bending rod structure of a single-degree-of-freedom folding and unfolding mechanism capable of realizing conversion between a plane regular hexagon and a space tetraoctadecahedron according to the present invention.

[0017] Figure 2 The figure is a schematic diagram of the assembly structure of a single-degree-of-freedom folding and unfolding mechanism II, which can realize the conversion between a plane regular hexagon and a spatial tetraoctadecahedron, and includes a semi-cylindrical connecting rod, a hollow arc-shaped kinematic pair I, and a solid arc-shaped kinematic pair II.

[0018] Figure 3 (a) is a schematic diagram of the overall structure of a single-degree-of-freedom folding and unfolding mechanism of the present invention that can realize the conversion between a plane regular hexagon and a spatial tetraoctadecahedron.

[0019] Figure 3 (b) is a schematic structural diagram of a single-degree-of-freedom folding and unfolding mechanism of the present invention that can realize the conversion between a planar regular hexagon and a spatial tetraoctadecahedron in a fully unfolded planar configuration.

[0020] Figure 3 (c) is a schematic structural diagram of a single-degree-of-freedom folding and unfolding mechanism of the present invention that can realize the conversion between a planar regular hexagon and a spatial tetraoctadecahedron in a completely closed polyhedron configuration.

[0021] In the figure, 1 - frame, 2 - type I connecting rod, 3 - type II connecting rod, 4 - bent rod, 5 - type I semi-cylindrical connecting rod, 6 - type II semi-cylindrical connecting rod, 7 - hollow arc kinematic joint I, 8 - solid arc kinematic joint II. Except for 1 - frame, a unit with one lead line indicates six units, and a unit with two leads indicates twelve units. DETAILED DESCRIPTION

[0022] A single-degree-of-freedom folding and unfolding mechanism capable of realizing the transformation between a regular hexagon in plane and a tetraoctadecahedron in space, such as Figure 1 、 Figure 2 、 Figure 3 (a) Figure 3 (b) Figure 3 As shown in (c), it includes a derived regular hexagonal frame 1, a type I connecting rod 2, a type II connecting rod 3, a bent rod 4 with an angle of 60 degrees, a type I semi-cylindrical connecting rod 5, and a type II semi-cylindrical connecting rod 6, wherein the semi-cylindrical connecting rods all have a revolute pair on the side close to the cylinder, a hollow arc-shaped moving pair 7 with an angle of 60 degrees, and a solid arc-shaped moving pair 8 with an angle of 60 degrees, and the lengths of the connecting rods are all equal.

[0023] The center of the frame 1 is a circular base, from which six branch connecting rods extend. They are arranged in a completely symmetrical manner. The angle between each two connecting rods is 60 degrees. The six branch connecting rods are respectively connected to the I-type connecting rod 2 through a revolute pair. The geometric center A of the revolute pair is i They are respectively located on a circle with o as the center and R1 as the radius.

[0024] There are six I-type connecting rods 2, one end of which is connected to the connecting rod of the frame through a revolute joint, and the connecting rod is parallel to the connecting rod of the frame, and the other end is connected to the II-type connecting rod 3 through a revolute joint, and the geometric center B of the revolute joint is i They are located on a circle with o as the center and R2 as the radius. The axis of the connecting rod 2 intersects the center of the frame 1.

[0025] There are twelve type II connecting rods 3. One end of each two type II connecting rods is hingedly connected to the same connecting rod 2 through a revolute pair. The angle between the connecting rods 3 is 120 degrees. Their axes coincide with each other. There is no interference between the rods. The geometric center C of the revolute pair is i They are respectively located on a circle with o as the center and R3 as the radius. The other end of the connecting rod 3 is hingedly connected to the bent rod 4 through a revolute pair.

[0026] There are six curved rods 4, with an included angle of 60 degrees. There is a cylindrical revolute pair at the top of the curved rod, where the geometric center of the cylinder is located at the top of the curved rod. The two ends of the branches extending from the curved rod 4 are respectively connected to two II-type connecting rods connected to different I-type connecting rods through a revolute pair. The revolute pair at the top of the curved rod is hinged to the revolute pair of the I-type semi-cylindrical connecting rod 5, and the geometric center D of the revolute pair is 1 / 4 of the revolute pair. i They are respectively located on a circle with o as the center and R4 as the radius.

[0027] There are twelve I-shaped semi-cylindrical connecting rods 5, and every two connecting rods 5 are hingedly connected to a bent rod 4 through a revolute pair, and their rectangular cross sections are located on the outside, and the rectangular cross sections of every two adjacent connecting rods 5 are coplanar.

[0028] There are twelve II-type semi-cylindrical connecting rods 6, one end of which is a revolute pair, and is hingedly connected to the I-type semi-cylindrical connecting rod 5 through a revolute pair. The rectangular cross-sections of the two are coplanar, and the other end is an arc-shaped boss with an arc-shaped groove, wherein the angle of the boss and the arc-shaped groove are both 60 degrees, and they share a common axis, axis E. i They are located on a circle with o as the center and R5 as the radius. The angle between two adjacent connecting rods 6 is 120 degrees, and connecting rods 5 and 6 form a planar regular hexagon.

[0029] There are six hollow arc-shaped moving pairs I7, which are fixedly connected to six II-type semi-cylindrical connecting rods 6 respectively. The arc surfaces between the two are tangent, the axes coincide, and the rectangular cross-section of one side of the arc-shaped pair coincides with the rectangular cross-section of the semi-cylinder.

[0030] The solid arc-shaped moving pair II8 is fixedly connected to the six II-type semi-cylindrical connecting rods 6. The rectangular cross section of one side of the arc-shaped moving pair coincides with the rectangular cross section of the semi-cylinder. The arc-shaped moving pair 8 is tangent to the arc-shaped surface of the arc-shaped moving pair 7, and their axes coincide, allowing relative motion between the two moving pairs.

[0031] The mechanism contains twelve single rings, wherein every three single rings form a regular hexagonal multi-ring mechanism, and every two regular hexagonal multi-ring mechanisms share a single ring. There are a total of six regular hexagonal multi-rings, and finally a regular hexagonal multi-ring mechanism containing twelve single rings is formed.

[0032] The present invention discloses a single-degree-of-freedom folding and unfolding mechanism capable of converting a planar regular hexagon to a spatial tetraoctadecahedron. The folding and unfolding of the entire mechanism is driven by the revolving pair of the connecting rod 1, and the mechanism is finally completely closed to form a spatial polyhedron. The mechanism has good enveloping properties during the folding and unfolding process and is easy to control. A novel deployable unit containing a coupling rod and a derived spatial deployable mechanism thereof have high rigidity, high reliability, and high operability, can realize the conversion from a planar geometric body to a spatial geometric body, and can be applied to small and medium-sized folding and unfolding antennas, envelope capture of objects by space exploration, and docking of space stations.

Claims

1. A single-degree-of-freedom folding and unfolding mechanism capable of converting a regular hexagon in plane into a tetraoctadecahedron in space, comprising: A frame (1), a type I connecting rod (2), a type II connecting rod (3), a bent rod with an angle of 60 degrees (4), a type I semi-cylindrical connecting rod (5), and a type II semi-cylindrical connecting rod (6); The center of the frame (1) is a circular base, from which six branch connecting rods extend. The six branch connecting rods are arranged in a completely symmetrical manner, and the angle between each two connecting rods is 60 degrees. The six branch connecting rods are respectively hingedly connected to the I-shaped connecting rod (2) through a revolute pair. There are six I-type connecting rods (2), one end of which is hingedly connected to the connecting rod of the frame through a revolute pair, and the connecting rod is parallel to the connecting rod of the frame; the other end is hingedly connected to the II-type connecting rod (3) through a revolute pair, and the axis of the rod of the I-type connecting rod (2) intersects with the center of the frame (1); There are twelve II-type connecting rods (3), one end of each two II-type connecting rods is hingedly connected to the same I-type connecting rod (2) through a revolute pair, the angle between the II-type connecting rods (3) is 120 degrees, the axes thereof coincide with each other, and the rods do not interfere with each other, and the other end of the II-type connecting rod (3) is hingedly connected to the bent rod (4) through a revolute pair; There are six bent rods (4), and the angle between the bent rods (4) is 60 degrees. The two ends of the branches extending from the bent rods (4) are respectively connected to two II-type connecting rods connected to different I-type connecting rods through a revolute pair; the revolute pair at the top of the bent rod is connected to the revolute pair of the I-type semi-cylindrical connecting rod (5) through a revolute pair. There are twelve I-shaped semi-cylindrical connecting rods (5), and every two I-shaped semi-cylindrical connecting rods (5) are hingedly connected to a bent rod (4) through a revolute pair, and their rectangular cross sections are located on the outside, and the rectangular cross sections of every two adjacent I-shaped semi-cylindrical connecting rods (5) are coplanar; There are twelve Type II semi-cylindrical connecting rods (6), one end of which is a revolute pair, which is hingedly connected to the Type I semi-cylindrical connecting rod (5) through a revolute pair, and the rectangular cross-sections of the two are coplanar; the other end is an arc-shaped boss with an arc-shaped groove, wherein the angle of the boss and the arc-shaped groove are both 60 degrees, and they share an axis, and the angle between two adjacent connecting rods is 120 degrees. The Type I semi-cylindrical connecting rod (5) and the Type II semi-cylindrical connecting rod (6) form a planar regular hexagon.

2. The single-degree-of-freedom folding and unfolding mechanism for converting a regular hexagon into a tetraoctadecahedron according to claim 1, characterized in that: There are six hollow arc-shaped moving pairs I (7), which are fixedly connected to six II-type semi-cylindrical connecting rods (6) respectively. The arc surfaces between the two are tangent, and the axes coincide with each other. The rectangular cross-section of one side of the hollow arc-shaped moving pair I (7) coincides with the rectangular cross-section of the semi-cylinder.

3. The single-degree-of-freedom folding and unfolding mechanism for converting a regular hexagon into a tetraoctadecahedron according to claim 2, characterized in that: The solid arc-shaped moving pair II (8) is fixedly connected to the six II-type semi-cylindrical connecting rods (6), and the rectangular cross-section of one side of the solid arc-shaped moving pair II (8) coincides with the rectangular cross-section of the semi-cylinder; the arc-shaped surfaces of the solid arc-shaped moving pair II (8) and the hollow arc-shaped moving pair I (7) are tangent, and the axes coincide, so that the two moving pairs can move relative to each other.

4. The single-degree-of-freedom folding and unfolding mechanism for converting a regular hexagon into a tetraoctadecahedron according to claim 1, characterized in that: The mechanism contains twelve single rings, wherein every three single rings form a regular hexagonal multi-ring mechanism, and every two regular hexagonal multi-ring mechanisms share a single ring. There are a total of six regular hexagonal multi-rings, and finally a regular hexagonal multi-ring mechanism containing twelve single rings is formed.

5. The single-degree-of-freedom folding and unfolding mechanism for converting a regular hexagon into a tetraoctadecahedron according to claim 1, characterized in that: The vertex of the bending rod has a cylindrical revolute pair, wherein the geometric center of the cylinder is located at the vertex of the bending rod.

6. The single-degree-of-freedom folding and unfolding mechanism for converting a regular hexagon into a tetraoctadecahedron according to claim 3, characterized in that: The I-type semi-cylindrical connecting rod (5) and the II-type semi-cylindrical connecting rod (6) both have a revolute pair on the side close to the cylinder, a hollow arc-shaped moving pair I (7) with an angle of 60 degrees, and a solid arc-shaped moving pair II (8) with an angle of 60 degrees. The lengths of the connecting rods are all equal.

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