A new type of multiple metamorphic mechanism for multifunctional design

Abstract

This invention discloses a novel multi-variable cell mechanism designed for multifunctional applications. It is an 8R single-ring linkage mechanism comprising eight links and eight revolute joints, with the links connected end-to-end. This novel multi-variable cell mechanism, by stiffening different revolute joints, can form different single-degree-of-freedom 7R variable cell mechanisms. Each derived variable cell mechanism has multiple motion branches and bifurcation configurations. The mechanism can bifurcate at bifurcation points, transitioning from one motion branch to another, thus realizing the cell transformation process. Through these different motion branches, different motion modes can be achieved, thereby realizing different functions. The novel multi-variable cell mechanism of this invention has multiple different motion branches, which can derive different motion modes. By analyzing the motion characteristics of different motion modes, different functional applications can be realized, such as: handling, rolling, hooking, peristalsis, and internal rotation.

Description

Technical Field

[0001] This invention belongs to the field of robotics technology, specifically relating to a novel multi-celled mechanism designed for multifunctional applications. Background Technology

[0002] Compared to the single-task characteristics of traditional robots, the new generation of intelligent robots can adapt to environmental and task requirements, exhibiting a "multi-purpose" capability. Reconfigurable robots can change their configuration, offering advantages such as high intelligence, high adaptability, and low cost. Correspondingly, reconfigurable mechanisms require only a single mechanism to meet multiple task requirements, something traditional mechanisms with only a single motion characteristic cannot achieve under complex working conditions. Variable-cell mechanisms are a type of reconfigurable mechanism; they are a novel type of linkage mechanism where the instantaneous degree of motion changes when the mechanism is in a singular position; subsequently, after passing through the singular position, the topology or degree of motion changes.

[0003] In the existing technology, the main research content on variable-cell mechanisms is on novel variable-cell mechanisms and their variable-cell forms, among which variable-cell mechanisms based on Bennett mechanisms and Bricard mechanisms have been studied most extensively. However, most of the variable-cell mechanisms constructed around these two over-constrained mechanisms are six-bar mechanisms, and these variable-cell mechanisms generally have fewer variable-cell numbers and fewer motion branches.

[0004] Furthermore, research on variable-cell mechanisms based on Bennett and Bricard mechanisms primarily focuses on six-bar mechanisms; studies on more complex seven-bar and eight-bar mechanisms are relatively scarce. Simultaneously, simpler variable-cell mechanisms have fewer kinematic branches. Additionally, existing technologies offer limited exploration of the functional applications of variable-cell mechanisms, and research on how to achieve "multi-purpose" mechanisms is also quite rare.

[0005] Therefore, providing a novel multi-variable cell mechanism with multiple motion branches and the ability to derive multiple motion modes has become a problem that the industry needs to solve. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the main objective of this invention is to provide a novel multi-variable cell mechanism that has multiple motion branches, can derive multiple motion modes, and corresponds to multiple different functions.

[0007] To achieve the above-mentioned main objectives, this invention discloses a novel multi-variable cell mechanism for multifunctional design. This novel multi-variable cell mechanism is an 8R single-ring linkage mechanism, which includes eight links and eight rotary joints. The links are connected to each other through the rotary joints; the eight links are connected end to end.

[0008] The novel multi-variable cell mechanism of this invention can form different single-degree-of-freedom 7R variable cell mechanisms (derived variable cell mechanisms) by stiffening different revolute pairs. Each derived variable cell mechanism has multiple motion branches (deformation modes) and bifurcation configurations. When the mechanism moves to the bifurcation point, it can bifurcate, moving from one motion branch to another, thereby realizing the variable cell process of the mechanism. Through these different motion branches, different motion modes can be realized, thereby achieving different functions.

[0009] The novel multi-variable cell mechanism of the present invention has a variety of different motion branches, which can lead to different motion modes. By analyzing the motion characteristics of different motion modes, different functional applications can be realized, such as: handling function, rolling function, hooking function, peristalsis function and internal rotation.

[0010] According to a specific embodiment of the present invention, the eight links include four A links, two B links, and two C links; the link length a, torsion angle α, and offset d in its DH parameters are as follows:

[0011] A rod: a A =L,α A =45°,d A =0;

[0012] B-stick: a B =L,α B =90°,d B =0;

[0013] C-bar: a C =L,α C =0°,d C =0;

[0014] Where L is a length constant.

[0015] According to one specific embodiment of the present invention, rod A has rods B and C on both sides, rod B has rod A on both sides, and rod C has rod A on both sides.

[0016] According to a specific embodiment of the present invention, the arrangement of the eight connecting rods is: ABACABAC (either clockwise or counterclockwise).

[0017] According to a specific embodiment of the present invention, by fixing the included angle between A and B to 0°, a derivative 7R single-degree-of-freedom variable cell mechanism is obtained.

[0018] According to a specific embodiment of the present invention, the included angle between A and B is fixed at 180° to obtain a derivative 7R single-degree-of-freedom variable cell mechanism II.

[0019] The present invention has the following beneficial effects:

[0020] The novel multi-variable cell mechanism of this invention has multiple derived variable cell mechanisms. Based on the motion characteristics of different motion branches, various motion modes can be derived, corresponding to various functions, such as handling and rolling functions. The design of this novel multi-variable cell mechanism and the exploration of the "one machine, multiple uses" of variable cell mechanisms will contribute to the research and development of reconfigurable robots for multi-functional design in the field of robotics.

[0021] To more clearly illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the novel multi-celled structure of Example 1;

[0023] Figure 2 This is a schematic diagram of the structure of the derived 7R single-degree-of-freedom variable cell mechanism in Example 1.

[0024] Figure 3 This is a schematic diagram of the motion branches and bifurcation configurations and their variable cell relationships of the derived 7R single-degree-of-freedom variable cell mechanism in Example 1;

[0025] Figure 4 This is a schematic diagram of the structure of the derived 7R single-degree-of-freedom variable cell mechanism II in Example 1;

[0026] Figure 5 This is a schematic diagram of the motion branches and bifurcation configurations and their variable cell relationships of the derived 7R single-degree-of-freedom variable cell mechanism II in Example 1;

[0027] Figure 6A This is a schematic diagram illustrating the transport function application of the novel multi-celled structure in Example 1;

[0028] Figure 6B This is a schematic diagram illustrating the rolling function application of the novel multi-celled structure in Example 1;

[0029] Figure 6C This is a schematic diagram illustrating the hooking function application of the novel multi-celled mechanism in Example 1;

[0030] Figure 6D This is a schematic diagram illustrating the peristaltic function application of the novel multi-celled structure in Example 1;

[0031] Figure 6E This is a schematic diagram of the in-hand rotation function application of the novel multi-celled mechanism in Example 1. Detailed Implementation

[0032] Many specific details are set forth in the following description in conjunction with embodiments in order to provide a full understanding of the invention. However, it should be understood that the following embodiments and detailed descriptions are for illustrative purposes only and do not limit the scope of protection of the invention.

[0033] Example 1

[0034] This embodiment provides a novel multi-variable structure, which is an 8R single-ring linkage mechanism, comprising eight links and eight revolute joints, with the links connected to each other via the revolute joints; the eight links are connected end to end.

[0035] The eight links include four A links, two B links, and two C links; the link length a, torsion angle α, and offset d in their DH parameters are as follows:

[0036] A rod: a A =L,α A =45°,d A =0;

[0037] B-stick: a B =L,α B =90°,d B =0;

[0038] C-bar: a C =L,α C =0°,d C =0;

[0039] Where L is a length constant, that is, the link parameter defined according to the DH rule, and the eight links have the same length.

[0040] The two sides of pole A are poles B and C, the two sides of pole B are pole A, and the two sides of pole C are pole A.

[0041] The eight connecting rods are arranged as follows: ABACABAC.

[0042] like Figure 1 As shown, the eight links are: Link 1 (A), Link 2 (B), Link 3 (A), Link 4 (C), Link 5 (A), Link 6 (B), Link 7 (A), and Link 8 (C). The eight revolute joints are: Joint 1 (9), Joint 2 (10), Joint 3 (11), Joint 4 (12), Joint 5 (13), Joint 6 (14), Joint 7 (15), and Joint 8 (16). These joints are located at the beginning and end of the links, and the links are connected through these joints. Figure 1 The relationship between each link and joint is shown in the diagram.

[0043] When the 8R single-ring linkage mechanism is stiffened in other special configurations, different derivative 7R single-degree-of-freedom variable-cell mechanisms are obtained.

[0044] See Figure 2 When the joint angle between link 1 (link A) and link 2 (link B) in the 8R single-ring linkage mechanism is 0, joint 2 (link B) is stiffened, resulting in a derived 7R single-degree-of-freedom variable-cell mechanism. At this point, link 1 and link 2 (link B) are essentially merged into a single link, called stiffened link 1 (link B), and joint 2 (link B) essentially disappears. The derived 7R single-degree-of-freedom variable-cell mechanism has nine motion branches and seven bifurcation points. The nine motion branches are, in order: unfolded Bennett 4R mechanism, folded Bennett 4R mechanism, linearly symmetric Bricard 6R mechanism, unfolded planar parallelogram 4R mechanism, anti-planar parallelogram 4R mechanism, spatial folded parallelogram 6R mechanism, and three different 7R mechanisms. The variable-cell path relationships formed by these motion branches through the bifurcation points are described in [reference needed]. Figure 3 .

[0045] See Figure 4 When the joint angle between link 2 (link B) and link 3 (link A) in the 8R single-ring linkage mechanism is 180°, joint 31 is stiffened, resulting in the derived 7R single-degree-of-freedom variable-cell mechanism 2. At this point, link 2 and link 3 are essentially merged into a single link, called stiffened link 218, and joint 31 essentially disappears. The derived 7R single-degree-of-freedom variable-cell mechanism 2 has ten motion branches and eight bifurcation points. The ten motion branches are, in order: a line-symmetric Bricard 6R mechanism, a folded Bennett 4R mechanism, a spherical 4R mechanism, three different double-joint coaxial mechanisms, a folded planar parallelogram 4R mechanism, a spatial unfolded parallelogram 6R mechanism, and two different 7R mechanisms. The variable-cell path relationships formed by these motion branches through the bifurcation points are described in [reference needed]. Figure 5 .

[0046] When the 8R single-ring linkage mechanism is rigidified in other special configurations, different derivative 7R single-degree-of-freedom variable cell mechanisms can be obtained. Examples will not be given in this embodiment.

[0047] The functional applications derived from the novel multi-variable cell mechanism of this embodiment are discussed below. This novel multi-variable cell mechanism is a novel variable cell mechanism designed for multi-functionality. Among the aforementioned motion branches, some branches with clear motion patterns are selected and evolved into five different mechanism functions: conveying function, rolling function, hooking function, peristaltic function, and in-hand rotation. (See [link to relevant documentation]). Figures 6A-6E .

[0048] like Figure 6AAs shown, the transport function can be achieved by motion branch 1, which is a Bennett 4R mechanism. In this mechanism, joint 2 (10) is rigidified, and joints 4 (12), 6 (14), and 8 (16) maintain their joint angles under the constraints of geometric parameters. In this Bennett 4R mechanism, the four movable joints are joint 1 (9), joint 3 (11), joint 5 (13), and joint 7 (15). Due to the geometric constraints on the joints, links 3 (3) and 4 (4) remain relatively fixed, links 5 (5) and 6 (6) remain relatively fixed, and links 7 (7) and 8 (8) remain relatively fixed. These three sets of links, each as a whole, together with the rigidified link 1, form the four links of the Bennett 4R mechanism. In this embodiment, the transport function uses the rigidified link 1 (17) as the frame, joint 1 (9) or joint 3 (11) as the drive joint, and a gripper or other end effector is attached to link 5 (5). By driving the Bennett 4R mechanism through the drive joint, the fifth link moves relative to the frame, which in turn drives the gripper to move, thereby achieving the transport function along a specified route.

[0049] like Figure 6B As shown, the rolling function can be achieved by motion branch 4, which is a planar parallelogram 4R mechanism. In this mechanism, joint 2 (10) is rigidified, and joints 3 (11), 6 (14), and 7 (15) maintain their joint angles under the constraints of geometric parameters. In this planar parallelogram 4R mechanism, the four movable joints are joint 1 (9), joint 4 (12), joint 5 (13), and joint 8 (16). Due to the geometric constraints on the joints, rigidified links 1 (17) and 3 (3) remain relatively fixed, as do links 5 (5), 6 (6), and 7 (7). These two sets of links, each acting as a unit, together with links 5 (4) and 8 (8), form the four links of the planar parallelogram 4R mechanism. In this embodiment, the rolling function does not have a fixed frame; the plane of the parallelogram formed by the mechanism is perpendicular to the ground. By controlling the drive joints differently, a certain link can roll forward relative to the ground. Alternating control of different links in the planar parallelogram 4R mechanism achieves the rolling function. For example, when the rigid link 17 and link 3 form a whole that contacts the ground, link 8 can be rotated by using joint 9 as the driving joint, thereby driving the other links to move; after all the links are in contact with the ground, link 8 can be rotated by using joint 19 as the driving joint, thereby driving the other links to move; the above two steps are performed alternately, which can realize the rolling function of the mechanism.

[0050] like Figure 6CAs shown, the hooking function can be achieved by motion branch 6, which is a spatial unfolded parallelogram 6R mechanism. At this time, joint 2 10 is stiffened, while joint 7 15, under the constraints of geometric parameters, maintains a constant joint angle. In this spatial unfolded parallelogram 6R mechanism, the six movable joints are joint 1 9, joint 3 11, joint 4 12, joint 5 13, joint 6 14, and joint 8 16. Due to the geometric constraints on the joints, link 6 6 and link 7 7 remain relatively fixed as a whole, together with the stiffened link 1 17, link 3 3, link 4 4, link 5 5, and link 8 8, forming the six links of the spatial unfolded parallelogram 6R mechanism. In this embodiment, the hooking function uses rigid link 17 as the frame. Rigid link 17, link 6, link 7, and link 8 form three sides of a parallelogram, while link 3, link 4, and link 5 form three sides of another parallelogram. Joint 3 11 is the driving joint. By controlling the driving joint, the mechanism moves until the two parallelograms form an "L-shaped" configuration in space, thus enabling it to function as a hook-like tool for hooking.

[0051] like Figure 6D As shown, the peristaltic function can be achieved by motion branch 15, which is a double-joint coaxial mechanism. In this mechanism, joint three 11 is rigidified, while joints two 10, four 12, six 14, seven 15, and eight 16, under this motion branch, are constrained by geometric parameters to maintain their joint angles. In this double-joint coaxial mechanism, the two movable joints are joint one 9 and joint five 13. Due to the geometric constraints on the joints, connecting rod one 1, rigid connecting rod two 18, and connecting rod four 4 remain relatively fixed, while connecting rod five 5, connecting rod six 6, connecting rod seven 7, and connecting rod eight 8 remain relatively fixed. These two sets of connecting rods, each acting as a unit, form the two connecting rods of the double-joint coaxial mechanism. In this embodiment, the peristaltic function does not have a fixed frame. The mechanism achieves its peristaltic function by controlling the drive joints, allowing the mechanism to alternate between unfolded and folded configurations. For example, when the double-joint coaxial mechanism is in the unfolded state, both parts are in contact with the ground. At this time, joint 9 or joint 13 can be used as the driving joint to fold the mechanism. Then, the driving joint can be moved in the opposite direction to unfold the mechanism again. The above two steps are repeated to achieve the peristaltic function of the mechanism.

[0052] like Figure 6EAs shown, the internal rotation function can be achieved by motion branch 12, which is a spherical 4R mechanism. In this mechanism, joint 3 11 is rigidified, while joints 1 9, 5 13, and 7 15, under this motion branch, are constrained by geometric parameters to maintain their joint angles. In this spherical 4R mechanism, the four movable joints are joint 2 10, joint 4 12, joint 6 14, and joint 8 16. Due to the geometric constraints on the joints, connecting rods 4 and 5 remain relatively fixed, connecting rods 6 and 7 remain relatively fixed, and connecting rod 8 and 1 remain relatively fixed. These three sets of connecting rods, each as a whole, together with the rigidified connecting rod 2 18, form the four connecting rods of the spherical 4R mechanism. In this embodiment, the spherical 4R mechanism uses the rigidified connecting rod 2 18 as the frame and any movable joint, such as joint 2 10, as the driving joint. The mechanism controls the drive joints to make the four links of the spherical 4R mechanism move relative to each other; for an object held between the four links, it exhibits rotational motion, realizing the mechanism's in-hand rotation function.

[0053] Although the present invention has been described above by way of embodiments, the above embodiments are only used to exemplify possible implementations of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent substitutions or changes made by those skilled in the art in accordance with the present invention should also be covered by the scope of protection defined by the claims of the present invention.

Claims

1. A novel multi-variable cell mechanism designed for multi-functional applications, characterized in that, The novel multi-variable cell mechanism is an 8R single-ring linkage mechanism, which includes eight linkages and eight revolute joints. The linkages are connected to each other through the revolute joints. The eight linkages are connected end to end. The eight linkages include four A-links, two B-links, and two C-links. Links B and C are on both sides of link A, links A are on both sides of link B, and links A are on both sides of link C. By fixing the included angle between A and B as 0°, a derived 7R single-degree-of-freedom variable cell mechanism is obtained. The derived 7R single-degree-of-freedom variable cell mechanism has nine motion branches and seven bifurcation points. The nine motion branches are, in order: unfolded Bennett 4R mechanism, folded Bennett 4R mechanism, linearly symmetric Bricard 6R mechanism, unfolded planar parallelogram 4R mechanism, anti-planar parallelogram 4R mechanism, spatial unfolded parallelogram 6R mechanism, and three different 7R mechanisms. By fixing the included angle between A and B to 180°, a second derivative 7R single-degree-of-freedom variable cell mechanism is obtained. The second derivative 7R single-degree-of-freedom variable cell mechanism has ten motion branches and eight bifurcation points. The ten motion branches are, in order: a line-symmetric Bricard 6R mechanism, a folded Bennett 4R mechanism, a spherical 4R mechanism, three different double-joint coaxial mechanisms, a folded planar parallelogram 4R mechanism, a spatial unfolded parallelogram 6R mechanism, and two different 7R mechanisms.

2. The novel multi-variable cell mechanism for multifunctional design according to claim 1, characterized in that, The link length a, torsion angle α, and offset d in the DH parameters of the eight links are as follows: Adequate: a A =L,a A =45°,d A =0; B. a B =L,a B =90°,d B =0; CD: a C =L,a C =0°,d C =0; Where L is a length constant.

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