Novel multi-metamorphic mechanism for multifunctional design

Abstract

The invention discloses a novel multi-metamorphic mechanism for multifunctional design, which is an 8R single-ring connecting rod mechanism and comprises eight connecting rods and eight revolute pair joints, and the connecting rods are connected through the revolute pair joints; the eight connecting rods are connected end to end. According to the novel multiple metamorphic mechanism disclosed by the invention, different single-degree-of-freedom 7R metamorphic mechanisms can be formed by stiffening different revolute pairs. Each derivative metamorphic mechanism has various motion branches and bifurcation structures, the mechanism can be bifurcated when moving to a bifurcation point, and enters another motion branch from one motion branch, so that the metamorphic process of the mechanism is realized; by means of the different motion branches, different motion modes can be achieved, and then different functions are achieved. The novel multi-metamorphic mechanism has multiple different motion branches, so that different motion modes can be derived, and different function applications such as a carrying function, a rolling function, a hooking function, a wriggling function and in-hand rotation can be realized by analyzing motion characteristics of the different motion modes.

Description

Technical Field

[0001] The invention belongs to the technical field of robots, and in particular relates to a novel multi-metamorphosis mechanism designed for multi-functions. Background Art

[0002] Compared with the single-task function of traditional robots, the new generation of intelligent robots can work adaptively according to environmental requirements and task requirements, and have the characteristics of "one machine for multiple uses". Reconfigurable robots can change their own configurations and have many advantages such as high intelligence, high adaptability, and low cost. Accordingly, reconfigurable mechanisms require the use of only one mechanism to meet multiple task requirements, which is not achievable by traditional mechanisms with only a single motion characteristic under complex working conditions. Metamorphosis is a type of reconfigurable mechanism, which is a new type of linkage mechanism: when the mechanism is in a singular position, the instantaneous activity of the mechanism will change; and after passing through the singular position, the topological structure or activity will change.

[0003] In the prior art, the main research contents on metamorphic mechanisms are new metamorphic mechanisms and their metamorphic forms, among which the metamorphic mechanisms based on Bennett mechanism and Bricard mechanism are the most extensively studied. However, most of the metamorphic mechanisms constructed around these two over-constrained mechanisms are six-bar mechanisms, and the number of metamorphic times and motion branches that these metamorphic mechanisms can achieve are generally small.

[0004] In addition, the research on metamorphic mechanisms based on Bennett mechanism and Bricard mechanism is mostly focused on six-bar mechanisms; the research on more complex seven-bar and eight-bar mechanisms is relatively scarce. At the same time, the simpler metamorphic mechanisms have fewer motion branches. In addition, there is little exploration of the functional application of metamorphic mechanisms in the prior art, and research on how to make the mechanism "one machine for multiple uses" is also relatively rare.

[0005] Therefore, providing a new type of multi-metamorphosis mechanism with multiple motion branches and capable of deriving multiple motion modes has become a problem that the industry needs to solve. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the main purpose of the present invention is to provide a new type of multiple metamorphic mechanism, which has multiple motion branches and can derive multiple motion modes corresponding to multiple different functions.

[0007] In order to achieve the above main objectives, the present invention discloses a new type of multi-metamorphosis mechanism with multi-functional design. The new type of multi-metamorphosis mechanism is an 8R single-ring connecting rod mechanism, which includes eight connecting rods and eight revolute joints. The connecting rods are connected by revolute joints; the eight connecting rods are connected end to end.

[0008] The novel multiple metamorphic mechanism of the present invention can form different single-degree-of-freedom 7R metamorphic mechanisms (derivative metamorphic mechanisms) by rigidifying different revolute pairs. Each derivative metamorphic mechanism has multiple motion branches (deformation modes) and bifurcation configurations. When the mechanism moves to a bifurcation point, it can bifurcate and enter from one motion branch to another motion branch, thereby realizing the metamorphic process of the mechanism; through these different motion branches, different motion modes can be realized, thereby realizing different functions.

[0009] The novel multiple metamorphosis 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: carrying function, rolling function, hooking function, peristalsis function and intra-hand rotation.

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

[0011] A rod: a A =L,α A =45°,d A =0;

[0012] B rod: a B =L,α B =90°,d B =0;

[0013] C rod: a C =L,α C =0°,d C =0;

[0014] Where L is the length constant.

[0015] According to a specific implementation of the present invention, the two sides of the A rod are the B rod and the C rod, the two sides of the B rod are the A rod, and the two sides of the C rod are the A rod.

[0016] According to a specific implementation of the present invention, the eight connecting rods are arranged in the following manner: ABACABAC (both clockwise and counterclockwise directions are possible).

[0017] According to a specific embodiment of the present invention, the angle between AB is fixed to 0°, and a derived 7R single-degree-of-freedom metamorphic mechanism is obtained.

[0018] According to a specific embodiment of the present invention, the angle between AB is fixed to 180°, and a second derivative 7R single-degree-of-freedom metamorphic mechanism is obtained.

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

[0020] The novel multiple metamorphic mechanism of the present invention has multiple derivative metamorphic mechanisms, and multiple motion modes can be derived according to the motion characteristics of different motion branches, corresponding to multiple different functions, such as carrying function, rolling function, etc. The design of the novel multiple metamorphic mechanism and the exploration of the "one machine with multiple uses" of the metamorphic mechanism are helpful for the research and development of reconfigurable robots with multi-functional design in the field of robotics.

[0021] In order to more clearly illustrate the purpose, technical solutions and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of the novel multiple metamorphosis mechanism of Example 1;

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

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

[0025] Figure 4 is a schematic structural diagram of the second derived 7R single-degree-of-freedom metamorphic mechanism in Example 1;

[0026] Figure 5 It is a schematic diagram of the motion branches and bifurcation configurations and their metamorphosis relationships of the second derived 7R single-degree-of-freedom metamorphic mechanism in Example 1;

[0027] Fig. 6A is a schematic diagram of the application of the transport function of the novel multiple metamorphosis mechanism of Example 1;

[0028] Figure 6B is a schematic diagram of the application of the rolling function of the novel multiple metamorphic cell mechanism of Example 1;

[0029] Figure 6C is a schematic diagram of the application of the hooking function of the novel multiple metamorphosis mechanism of Example 1;

[0030] Fig.6D Schematic diagram of the application of the peristaltic function of the novel multiple metamorphosis mechanism of Example 1;

[0031] Fig. 6E Schematic diagram of the application of the intra-hand rotation function of the novel multiple metamorphosis mechanism of Example 1. DETAILED DESCRIPTION

[0032] In the following description, many specific details are explained in conjunction with the embodiments to facilitate a full understanding of the present invention. However, it should be understood that the following embodiments and detailed descriptions are only for illustrative purposes and do not limit the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment provides a novel multiple metamorphic mechanism, which is an 8R single-ring connecting rod mechanism, including eight connecting rods and eight revolute joints, and the connecting rods are connected by revolute joints; the eight connecting rods are connected end to end.

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

[0036] A rod: a A =L,α A =45°,d A =0;

[0037] B rod: a B =L,α B =90°,d B =0;

[0038] C rod: a C =L,α C =0°,d C =0;

[0039] Among them, L is the length constant, that is, the connecting rod parameter defined according to the DH law, and the eight connecting rods have the same length.

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

[0041] The arrangement of the eight connecting rods is: ABACABAC.

[0042] like Figure 1 As shown, the eight connecting rods are: connecting rod 1 (A rod), connecting rod 2 (B rod), connecting rod 3 (A rod), connecting rod 4 (C rod), connecting rod 5 (A rod), connecting rod 6 (B rod), connecting rod 7 (A rod) and connecting rod 8 (C rod). 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. The joints are located at the head and tail ends of the connecting rods, and the connecting rods are connected through the joints. Figure 1 The relationship between each connecting rod and the joint can be seen as shown.

[0043] When the 8R single-loop linkage mechanism is in other special configurations and a certain joint is rigidified, different derivative 7R single-degree-of-freedom metamorphic mechanisms are obtained.

[0044] See also Figure 2 , when the joint angle between link 1 (A rod) and link 2 (B rod) of the 8R single-loop linkage mechanism is 0, the joint 2 10 is rigidified to obtain a derived 7R single-degree-of-freedom metamorphic mechanism 1. At this time, link 1 and link 2 are essentially merged into one rod, called rigidified link 17, and joint 2 10 essentially disappears. The derived 7R single-degree-of-freedom metamorphic mechanism 1 has nine motion branches and seven bifurcation points. The nine motion branches are: unfolded Bennett 4R mechanism, folded Bennett 4R mechanism, line-symmetric Bricard 6R mechanism, unfolded planar parallelogram 4R mechanism, anti-planar parallelogram 4R mechanism, space folded parallelogram 6R mechanism and three different 7R mechanisms. The metamorphic path relationship of these motion branches formed through bifurcation points can be found in Figure 3 .

[0045] See also Figure 4 When the joint angle between link 2 (B rod) and link 3 (A rod) of the 8R single-loop linkage mechanism is 180°, the joint 3 11 is rigidified to obtain the derived 7R single-degree-of-freedom metamorphic mechanism 2. At this time, link 2 2 and link 3 3 are essentially merged into one rod, called rigidified link 2 18, and joint 3 11 essentially disappears. The derived 7R single-degree-of-freedom metamorphic mechanism 2 has ten motion branches and eight bifurcation points. The ten motion branches are: line-symmetric Bricard 6R mechanism, folded Bennett 4R mechanism, spherical 4R mechanism, 3 different double-joint coaxial mechanisms, folded plane parallelogram 4R mechanism, space folded parallelogram 6R mechanism and 2 different 7R mechanisms. The metamorphic path relationship of these motion branches formed through bifurcation points can be found in Figure 5 .

[0046] When the 8R single-loop linkage mechanism is in other special configurations and a certain joint is rigidified, different derivative 7R single-degree-of-freedom metamorphic mechanisms can be obtained, which will not be given as examples in this embodiment.

[0047] The following discusses the functional applications derived from the novel multiple metamorphosis mechanism of this embodiment. The novel multiple metamorphosis mechanism of this embodiment is a novel metamorphosis mechanism designed for multi-functions. Among the above-mentioned motion branches, some branches with clear motion patterns are selected to evolve into five different mechanism functions, namely, carrying function, rolling function, hooking function, peristalsis function and intra-hand rotation, see Figure 6A-6E .

[0048] like Fig. 6AAs shown, the transport function can be realized by motion branch 1, which is a Bennett 4R mechanism. At this time, joint 2 10 is rigidified, and joint 4 12, joint 6 14 and joint 8 16 are constrained by geometric parameters under this motion branch to keep the joint angle unchanged. In this Bennett 4R mechanism, the four movable joints are joint 1 9, joint 3 11, joint 5 13 and joint 7 15; because the joints are subject to geometric constraints, link 3 3 and link 4 4 remain relatively fixed, link 5 5 and link 6 6 remain relatively fixed, link 7 7 and link 8 8 remain relatively fixed, and these three groups of links each as a whole together with the rigidified link 1 constitute the four links of the Bennett 4R mechanism. The transport function in this embodiment uses the rigidified link 1 17 as the frame, joint 1 9 or joint 3 11 as the driving joint, and a clamp or other end effector is attached to the link 5 5. The Bennett 4R mechanism is driven to move by driving the joint, so that the connecting rod 5 moves relative to the frame and drives the clamping claw to move, thereby realizing the transportation function of the specified route.

[0049] like Figure 6B As shown, the rolling function can be realized by the motion branch 4, which is a plane parallelogram 4R mechanism. At this time, the joint 2 10 is rigidified, and the joint 3 11, the joint 6 14 and the joint 7 15 are constrained by geometric parameters under this motion branch to keep the joint angle unchanged. In this plane parallelogram 4R mechanism, the four movable joints are joint 1 9, joint 4 12, joint 5 13 and joint 8 16; because the joints are subject to geometric constraints, the rigidified link 1 17 and the link 3 3 remain relatively fixed, and the link 5 5, the link 6 6 and the link 7 7 remain relatively fixed. These two groups of links, as a whole, together with the link 5 4 and the link 8 8, form the four links of the plane parallelogram 4R mechanism. The rolling function in this embodiment does not have a fixed frame. The plane where the parallelogram formed by the mechanism is located is perpendicular to the ground. By controlling the driving joints differently, a certain link is made to roll forward relative to the ground, and the rolling function of the mechanism can be realized by alternately controlling different links of the plane parallelogram 4R mechanism. For example, when the rigidified link 1 17 and link 3 3 are in contact with the ground, the joint 1 9 is used as the driving joint to control the link 8 8 to rotate and drive the other links to move; after all the links are in contact with the ground, the joint 8 19 is used as the driving joint to control the link 8 8 to rotate and drive the other links to move; the above two steps are performed alternately to realize the directional rolling function of the mechanism.

[0050] like Figure 6CAs shown, the hooking function can be realized by the motion branch 6, which is a space folding parallelogram 6R mechanism. At this time, the joint 2 10 is rigidified, and the joint 7 15 is constrained by geometric parameters under this motion branch to keep the joint angle unchanged. In this space folding parallelogram 6R mechanism, the 6 movable joints are joint 1 9, joint 3 11, joint 4 12, joint 5 13, joint 6 14 and joint 8 16; because the joints are subject to geometric constraints, the link 6 6 and the link 7 7 remain relatively fixed as a whole, and together with the rigidized link 1 17, link 3 3, link 4 4, link 5 5 and link 8 8, they form the 6 links of the space folding parallelogram 6R mechanism. The hooking function in this embodiment uses the rigidized link 1 17 as the frame, the rigidized link 1 17, the link 6 6, the link 7 7 and the link 8 8 form three sides of a parallelogram, and the link 3 3, the link 4 4 and the link 5 5 form three sides of another parallelogram. The joint 3 11 is used as the driving joint, and through the control of the driving joint, the mechanism moves to the "L-shaped" configuration formed by the above two parallelograms in space, so that it can be used as a tool in the form of a hook claw to realize the hooking function of the mechanism.

[0051] like Fig.6D As shown, the creep function can be realized by the motion branch 15, which is a double-joint coaxial mechanism. At this time, joint three 11 is rigidified, while joint two 10, joint four 12, joint six 14, joint seven 15 and joint eight 16 are constrained by geometric parameters under this motion branch to keep the joint angle unchanged. In this double-joint coaxial mechanism, the two movable joints are joint one 9 and joint five 13; because the joints are subject to geometric constraints, connecting rod one 1, rigidified connecting rod two 18 and connecting rod four 4 remain relatively fixed, connecting rod five 5, connecting rod six 6, connecting rod seven 7 and connecting rod eight 8 remain relatively fixed, and these two groups of connecting rods each serve as a whole to form two connecting rods of the double-joint coaxial mechanism. The creep function in this embodiment does not have a fixed frame. The mechanism controls the driving joints so that the mechanism alternates between the two configurations of unfolding and folding, thereby realizing the creep function of the mechanism. For example, when the double-joint coaxial mechanism is in the expanded state, both parts are in contact with the ground. At this time, using joint 1 9 or joint 5 13 as the driving joint can make the mechanism fold; then the driving joint moves in the opposite direction to make the mechanism expand again; the above two steps are performed alternately to realize the creeping function of the mechanism.

[0052] like Fig. 6EAs shown, the internal rotation function of the hand can be realized by the motion branch 12, which is a spherical 4R mechanism. At this time, joint three 11 is rigidified, while joint one 9, joint five 13 and joint seven 15 are constrained by geometric parameters under this motion branch to keep the joint angle unchanged. In this spherical 4R mechanism, the four movable joints are joint two 10, joint four 12, joint six 14 and joint eight 16; because the joints are subject to geometric constraints, connecting rod four 4 and connecting rod five 5 remain relatively fixed, connecting rod six 6 and connecting rod seven 7 remain relatively fixed, and connecting rod eight 8 and connecting rod one 1 remain relatively fixed. These three groups of connecting rods are each as a whole together with the rigidized connecting rod two 18 to form the four connecting rods of the spherical 4R mechanism. The spherical 4R mechanism in this embodiment uses the rigidized connecting rod two 18 as the frame and any movable joint, such as: joint two 10, as the driving joint. The mechanism controls the driving joints to make the four connecting rods of the spherical 4R mechanism produce relative motion; for the object grasped between the four rods, it exhibits rotational motion, realizing the in-hand rotation function of the mechanism.

[0053] Although the present invention has been described above through embodiments, the above embodiments are only used to exemplarily describe the feasible implementation schemes of the present invention, and are not used to limit the protection scope 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 protection scope defined by the claims of the present invention.

Claims

1. A novel multi-metamorphosis mechanism for multi-functional design, characterized in that: The novel multiple metamorphic mechanism is an 8R single-ring connecting rod mechanism, which includes eight connecting rods and eight revolute joints. The connecting rods are connected by revolute joints; the eight connecting rods are connected end to end.

2. The novel multiple metamorphosis mechanism according to claim 1, characterized in that: The eight connecting rods include four A rods, two B rods, and two C rods; the connecting rod length a, torsion angle α, and offset d in the DH parameters 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 the length constant.

3. The novel multiple metamorphosis mechanism according to claim 2, characterized in that: The two sides of rod A are rod B and rod C, the two sides of rod B are rod A, and the two sides of rod C are rod A.

4. The novel multiple metamorphosis mechanism according to claim 3, characterized in that: The eight connecting rods are arranged in the following manner: ABACABAC.

5. The novel multiple metamorphosis mechanism according to claim 4, characterized in that: Fix the angle between AB to 0° and obtain a derived 7R single-degree-of-freedom metamorphic mechanism.

6. The novel multiple metamorphosis mechanism according to claim 4, characterized in that: Fix the angle between AB to be 180°, and obtain the second derived 7R single-degree-of-freedom metamorphic mechanism.

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