Parallel mechanical joint simulating human ankle movement

Abstract

The invention relates to a humanoid robot, in particular to a parallel mechanical joint simulating human ankle movement. The invention relates to a parallel mechanical joint, and aims to provide a parallel mechanical joint simulating human ankle movement so as to realize two degrees of freedom of simulating human ankle movement on the basis of ensuring high rigidity and movement precision, and the parallel mechanical joint is simple in structure, good in supporting performance and capable of ensuring a certain movement space. According to the technical scheme, the parallel mechanical joint simulating human ankle movement is characterized by comprising a vertically-arranged shank, a foot connected to the bottom end of the shank through a composite rotating shaft, an RPR push rod branch connected between the shank and the composite rotating shaft and an SPS push rod branch connected between the shank and the foot.

Description

Technical Field

[0001] The present invention relates to a humanoid robot, specifically a parallel mechanical joint that mimics the movement of the human ankle. Background Art

[0002] In recent years, due to its highly humanoid form and motion capabilities, humanoid robots have shown broad application prospects in fields such as service, medical treatment, rescue, and industrial collaboration. As an ideal carrier for humans to interact with complex environments, humanoid robots need to possess motion flexibility, environmental adaptability, and energy efficiency similar to those of the human body. The mechanical lower limbs, as the core motion units, directly determine the implementation effects of dynamic behaviors such as walking, running, and obstacle crossing. The ankle joint, which connects the foot and the calf and is the part that directly contacts the ground, is of utmost importance.

[0003] However, there is currently little research on the ankle joints of humanoid robots. Although traditional serial ankle joint structures (such as the single-axis or double-axis rotation mechanisms commonly found in humanoid robots) have the characteristics of a wide range of motion and simple control logic, they suffer from problems such as low load-bearing stiffness and delayed dynamic response, making it difficult to meet the requirements of the human ankle joint to withstand multi-directional impact loads during movements such as walking and jumping. Existing parallel ankle joint designs (such as the multi-degree-of-freedom mechanical ankle described in CN119568309A) have improved structural rigidity, but due to the complex coupling of the motion chain, it is difficult to solve the degrees of freedom, and it is difficult to accurately simulate the motion characteristics of the bending degree of the human ankle joint. In addition, most existing solutions use a full-drive mode to achieve multi-degree-of-freedom motion, resulting in a large system inertia, high energy consumption, and a lack of adaptive compensation ability for uneven ground. In complex terrains such as slopes and gravel roads, joint locking or trajectory misalignment is likely to occur, severely restricting the motion flexibility and scene applicability of humanoid robots.

[0004] Therefore, there is an urgent need to propose a parallel mechanical joint that mimics the movement of the human ankle to overcome the above defects. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the above background art and provide a parallel mechanical joint that mimics the movement of the human ankle. On the basis of ensuring high stiffness and motion accuracy, it can achieve two degrees of freedom of bionic human ankle joint movement, and has a simple structure, good support performance, and can ensure a certain movement space.

[0006] The technical solution provided by the present invention is as follows:

[0007] A parallel mechanical joint that mimics the movement of the human ankle, characterized in that it includes a vertically arranged calf, a foot connected to the bottom end of the calf through a composite rotating shaft, an RPR push rod branch connected between the calf and the composite rotating shaft, and an SPS push rod branch connected between the calf and the foot.

[0008] The composite rotating shaft includes a third connecting rod, a fourth connecting rod, and a fifth connecting rod that are integrally connected; one end of the third connecting rod is fixed to the middle part of the fifth connecting rod and is perpendicular to the fifth connecting rod; one end of the fourth connecting rod is fixed to the middle part of the third connecting rod and is perpendicular to the third connecting rod, and is parallel to the fifth connecting rod; the axes of the third connecting rod, the fourth connecting rod, and the fifth connecting rod are coplanar; or,

[0009] The composite rotating shaft includes a third connecting rod, a fourth connecting rod, a fifth connecting rod, and a sixth connecting rod that are integrally connected; one end of the fourth connecting rod is fixed to the middle part of the third connecting rod and is perpendicular to the third connecting rod; the fifth connecting rod is connected to the third connecting rod through the sixth connecting rod and is parallel to the fourth connecting rod; both ends of the sixth connecting rod are respectively connected to the middle part of the fifth connecting rod and the middle part of the third connecting rod, and the sixth connecting rod is perpendicular to the third connecting rod, the fourth connecting rod, and the fifth connecting rod; the axes of the third connecting rod, the fourth connecting rod, and the fifth connecting rod are coplanar.

[0010] The RPR push rod branch includes a first connecting rod, a second rotating pair, a first electric push rod, and a third rotating pair that are sequentially connected between the calf and the composite rotating shaft.

[0011] The first electric push rod includes a first driving motor installed on a first push rod base, a first push rod sleeve with one end installed on the first push rod base, and a first push rod with one end slidably engaged with the other end of the first push rod sleeve.

[0012] The SPS push rod branch includes a second connecting rod, a first ball hinge, a second electric push rod, and a second ball hinge that are sequentially connected between the calf and the foot.

[0013] The second electric push rod includes a second driving motor installed on a second push rod base, a second push rod sleeve with one end installed on the second push rod base, and a second push rod with one end slidably engaged with the other end of the second push rod sleeve.

[0014] The calf is vertically arranged, and the hinge ear at the bottom end of the calf cooperates with the third connecting rod to form a first rotating pair that can swing around a horizontal axis; one end of the first connecting rod and one end of the second connecting rod are fixed to the upper part of the calf, the horizontal plane projection of the axis of the first connecting rod is perpendicular to the horizontal plane projection of the axis of the second connecting rod and perpendicular to the axis of the first rotating pair at the bottom end of the calf; the other end of the first connecting rod is connected to the second rotating pair; the other end of the second connecting rod is fixed with a first spherical shell for cooperating with a first sphere to form a first ball hinge.

[0015] The foot is connected to the composite rotating shaft through a fourth rotating pair; the fourth rotating pair is formed by the hinge ear at the upper end of the foot cooperating with the fifth connecting rod, the axis of the fourth rotating pair is horizontally arranged and perpendicular to the front-back direction of the foot; a second spherical shell for cooperating with a second sphere to form a second ball hinge is also installed at the upper end of the foot.

[0016] One end of the first push rod sleeve and the first drive motor are both installed at the bottom end of the first push rod base; the hinge ear provided at the top end of the first push rod base is engaged with the other end of the first link through a hinge shaft to form a second rotating pair; the other end of the first push rod is engaged with the other end of the fourth link through a hinge shaft to form a third rotating pair.

[0017] One end of the second push rod sleeve and the second drive motor are both installed at the bottom end of the second push rod base; a first sphere that forms a first spherical hinge with the first spherical shell is provided at the top end of the second push rod base; the second push rod extends downward from the second electric push rod and a second sphere for forming a second spherical hinge with the second spherical shell is fixed at the end.

[0018] The axis of the first rotating pair, the axis of the second rotating pair, and the axis of the third rotating pair are parallel to each other and perpendicular to the axis of the fourth rotating pair.

[0019] The beneficial effects of the present invention are as follows:

[0020] The present invention can realize the function of imitating the human ankle with a double-branch parallel mechanical joint, having good support performance and high load-bearing capacity. By driving the cooperation of the two push rod branches, two degrees of freedom can be achieved, and the pose control of the mechanical ankle joint can be flexibly realized, which helps to ensure the balance of the fuselage during the movement of the connected machine legs and the like. The present invention can, while ensuring the motion accuracy, stiffness and support performance, increase the calf reinforcing ribs, cut off the inner space of the foot, simplify the structure, reduce the material cost, and ensure the motion space of the ankle joint. Description of the Drawings

[0021] Figure 1 It is a three-dimensional structural schematic diagram of Embodiment 1 of the present invention.

[0022] Figure 2 It is Figure 1 a three-dimensional structural schematic diagram of the calf in

[0023] Figure 3 It is Figure 1 a three-dimensional structural schematic diagram of the RPR push rod branch in

[0024] Figure 4 It is Figure 1 a three-dimensional structural schematic diagram of the SPS push rod branch in

[0025] Figure 5 It is Figure 1 a three-dimensional structural schematic diagram of the composite rotating shaft in

[0026] Figure 6 It is Figure 1 a three-dimensional structural schematic diagram of the foot in

[0027] Figure 7 It is a three-dimensional structural schematic diagram of Embodiment 2 of the present invention.

[0028] Figure 8 For Figure 7 the three-dimensional structural schematic diagram of the composite rotating shaft in

[0029] Reference numerals:

[0030]

[0031] Specific embodiments

[0032] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0033] The present invention will be further described below in conjunction with the embodiments shown in the accompanying drawings.

[0034] Embodiment 1

[0035] Figure 1 The parallel mechanical joint imitating the movement of a human ankle shown includes a calf 1, a foot 5 connected to the bottom end of the calf through a composite rotating shaft 4, an RPR push rod branch 2 connected between the calf and the composite rotating shaft 4, and an SPS push rod branch 3 connected between the calf and the foot.

[0036] As Figure 2 shown, the calf is vertically arranged. One end of the first link 11 and one end of the second link 14 are both fixed to the upper part of the calf 1. The horizontal projection of the axis of the first link is perpendicular to the horizontal projection of the sixth link and perpendicular to the axis of the first rotating pair 13 at the bottom end of the calf; a first spherical shell 12 is fixed to the other end of the second link 14.

[0037] As Figure 5 shown, the composite rotating shaft 4 includes a third link 41, a fourth link 42 and a fifth link 43 connected as a whole; one end of the third link 41 is fixed to the middle part of the fifth link 43 and perpendicular to the fifth link; one end of the fourth link 42 is fixed to the middle part of the third link 41 and perpendicular to the third link, and parallel to the fifth link; the axes of the third link, the fourth link and the fifth link are coplanar.

[0038] As Figure 3As shown in the figure, the RPR push rod branch 2 includes a first connecting rod 11, a second rotating pair 21, a first electric push rod, and a third rotating pair 26 that are sequentially connected between the lower leg 1 and the composite rotating shaft 4; the first electric push rod includes a first push rod base 22, a first driving motor 23, a first push rod sleeve 24, and a first push rod 25; one end of the first push rod 25 is inserted into one end of the first push rod sleeve 24 and is slidably matched with the first push rod sleeve, and the other end of the first push rod sleeve and the first driving motor 23 are both installed at the bottom end of the first push rod base 22; a hinge ear for forming the second rotating pair 21 is provided at the top end of the first push rod base; the other end of the first push rod 25 is matched with the other end of the fourth connecting rod 42 through a hinge shaft to form the third rotating pair 26.

[0039] As Figure 4 shown in the figure, the SPS push rod branch 3 includes a second connecting rod 14, a first ball joint 31, a second electric push rod, and a second ball joint 36 that are sequentially connected between the lower leg 1 and the foot 5; the second electric push rod includes a second push rod base 32, a second driving motor 33, a second push rod sleeve 34, and a second push rod 35. One end of the second push rod 35 is inserted into one end of the second push rod sleeve 34 and is slidably matched with the second push rod sleeve. The other end of the second push rod sleeve and the second driving motor 33 are both installed at the bottom end of the second push rod base 32; a first sphere is provided at the top end of the second push rod base, and the first sphere and the first spherical shell 12 cooperate to form the first ball joint 31; the second push rod extends downward from the second push rod sleeve, and a second sphere is fixed at the other end of the second push rod. The second sphere and the second spherical shell 52 cooperate to form the second ball joint 36.

[0040] As Figure 6 shown in the figure, a hinge ear is provided at the upper end of the foot 5, and the hinge ear and the fifth connecting rod 43 that can rotate around the horizontal axis cooperate to form a fourth rotating pair 51, and the axis of the fourth rotating pair is perpendicular to the front-back direction of the foot; and a second spherical shell 52 is also installed at the upper end of the foot 5, and the second spherical shell and the second sphere 36 cooperate to form the second ball joint 36. From Figure 1 it can be seen that in the horizontal plane projection, the third connecting rod 41 and the fourth connecting rod 42 are located on the left side of the fifth connecting rod 43, and the second ball joint 36 is located on the right side of the fifth connecting rod 43.

[0041] In this embodiment, the third connecting rod 41 is horizontally arranged and is rotatably matched with the hinge ear at the bottom end of the lower leg 1 to form a first rotating pair 13. The other end of the fourth connecting rod 42 is rotatably matched with the hinge ear at one end of the first push rod 25 of the RPR push rod branch 2 through a hinge shaft to form a third rotating pair 26. The fifth connecting rod 43 is rotatably matched with the hinge ear at the upper end of the foot 5 to form a fourth rotating pair 51.

[0042] In this embodiment, the axis of the first driving motor 23 is parallel to the axis of the first push rod sleeve 24. The first driving motor and the first push rod sleeve are installed on the same side of the first push rod base 22, and the second rotating pair 21 is on the other side of the first push rod base 22. The axes of the second rotating pair 21 and the third rotating pair 26 are parallel and perpendicular to the axis of the first push rod.

[0043] The axis of the second driving motor 33 is parallel to the axis of the second push rod sleeve 34. The second driving motor and the second push rod sleeve are installed on the same side of the second push rod base 32, and the first ball hinge 31 is installed on the other side of the second push rod base 32.

[0044] In this embodiment, the axes of the first rotating pair 13, the second rotating pair 21, and the third rotating pair 26 are parallel to each other and perpendicular to the axis of the fourth rotating pair 51.

[0045] Embodiment 2

[0046] The difference between this embodiment and Embodiment 1 lies only in the structure of the composite rotating shaft, and the rest are the same.

[0047] As Figure 7 、 8 shown, the difference between the composite rotating shaft 4 in this embodiment and the composite rotating shaft in Embodiment 1 is that a sixth connecting rod 44 is added, and the fifth connecting rod 43 is no longer directly connected to the third connecting rod 41. It can be seen from Figure 8 that: the fifth connecting rod 43 is connected to the third connecting rod 41 through the sixth connecting rod 44; both ends of the sixth connecting rod 44 are respectively connected to the middle parts of the fifth connecting rod 43 and the third connecting rod 41, and the sixth connecting rod is perpendicular to the third connecting rod 41, the fourth connecting rod 42, and the fifth connecting rod 43. It can be seen from Figure 8 the horizontal projection that: the axis of the fourth connecting rod 42 coincides with the axis of the fifth connecting rod 43 and is orthogonal to the axis of the third connecting rod 41, and the axis of the sixth connecting rod is located at the intersection point.

[0048] In this embodiment, the axes of the third connecting rod 41 and the fourth connecting rod 42 are coplanar, the axes of the fourth connecting rod 42, the fifth connecting rod 43, and the sixth connecting rod 44 are coplanar, and the axes of the third connecting rod 41 and the fifth connecting rod 43 are skew; the third connecting rod 41 is the rotating shaft of the first rotating pair 13, and the fifth connecting rod 43 is the rotating shaft of the fourth rotating pair 51;

[0049] The axes of the second rotating pair 21, the third rotating pair 26, and the first rotating pair are parallel to each other and perpendicular to the axis of the fourth rotating pair 51; the axes of the fourth connecting rod 42 and the fifth connecting rod 43 are parallel to each other and perpendicular to the axis of the sixth connecting rod 44 and the axis of the third connecting rod 41.

[0050] Working principle:

[0051] The parallel mechanical joint can achieve the degrees of freedom and functions required for bionic human ankle joint movement, including the radial rotation degrees of freedom in two directions. The composite rotating shaft is similar to a Hooke joint and is connected to the calf and the foot, with two rotating degrees of freedom. By driving the RPR push rod branch with a motor, the left and right swing of the foot can be achieved, and by driving the SPS push rod branch with a motor, the front and back swing of the foot can be achieved ( Figure 6 The arrow in Figure 6 indicates the front). When the two push rod branches cooperate with each other, precise movement control of the foot component can be achieved. When combined with other mechanical components to form a robot, the balance of the fuselage movement can be ensured, and the function of bionic human ankle joint movement can be realized.

Claims

1. A parallel mechanical joint imitating human ankle movement, characterized in that: It includes a vertically arranged calf (1), a foot (5) connected to the bottom end of the calf through a composite rotating shaft (4), an RPR push rod branch (2) connected between the calf (1) and the composite rotating shaft, and an SPS push rod branch (3) connected between the calf and the foot.

2. The parallel mechanical joint imitating human ankle movement according to claim 1, wherein: The composite rotating shaft includes a third connecting rod (41), a fourth connecting rod (42), and a fifth connecting rod (43) that are integrally connected; one end of the third connecting rod is fixed to the middle part of the fifth connecting rod and perpendicular to the fifth connecting rod; one end of the fourth connecting rod is fixed to the middle part of the third connecting rod and perpendicular to the third connecting rod, and parallel to the fifth connecting rod; the axes of the third connecting rod, the fourth connecting rod, and the fifth connecting rod are coplanar; or, The composite rotating shaft includes a third connecting rod, a fourth connecting rod, a fifth connecting rod, and a sixth connecting rod (44) that are integrally connected; one end of the fourth connecting rod is fixed to the middle part of the third connecting rod and perpendicular to the third connecting rod; the fifth connecting rod is connected to the third connecting rod through the sixth connecting rod and is parallel to the fourth connecting rod; both ends of the sixth connecting rod are respectively connected to the middle part of the fifth connecting rod and the middle part of the third connecting rod, and the sixth connecting rod is perpendicular to the third connecting rod, the fourth connecting rod, and the fifth connecting rod.

3. The parallel mechanical joint imitating human ankle movement according to claim 2, characterized in that: The RPR push rod branch (2) includes a first connecting rod (11), a second rotating pair (21), a first electric push rod, and a third rotating pair (26) that are sequentially connected between the calf (1) and the composite rotating shaft (4). The first electric push rod includes a first driving motor (23) installed on a first push rod base (22), a first push rod sleeve (24) with one end installed on the first push rod base, and a first push rod (25) with one end slidingly matched with the other end of the first push rod sleeve.

4. The parallel mechanical joint imitating human ankle movement according to claim 3, characterized in that: The SPS push rod branch (3) includes a second connecting rod (14), a first spherical hinge (31), a second electric push rod, and a second spherical hinge (36) that are sequentially connected between the calf (1) and the foot (5); The second electric push rod includes a second driving motor (33) installed on a second push rod base (32), a second push rod sleeve (34) with one end installed on the second push rod base, and a second push rod (35) with one end slidingly matched with the other end of the second push rod sleeve.

5. The parallel mechanical joint imitating human ankle movement according to claim 4, characterized in that: The calf (1) is vertically arranged, and the hinge ear at the bottom end of the calf cooperates with the third connecting rod (41) to form a first rotating pair (13) that can swing around a horizontal axis; one end of the first connecting rod (11) and one end of the second connecting rod (14) are fixed to the upper part of the calf. The horizontal plane projection of the axis of the first connecting rod is perpendicular to the horizontal plane projection of the axis of the second connecting rod and perpendicular to the axis of the first rotating pair; the other end of the first connecting rod is connected to the second rotating pair (21); the other end of the second connecting rod (14) is fixed with a first spherical shell (12) for cooperating with a first sphere to form a first spherical hinge.

6. The parallel mechanical joint imitating human ankle movement according to claim 5, wherein: The foot (5) is connected to the composite rotating shaft through a fourth rotating pair (51); the fourth rotating pair is formed by the hinge ear at the upper end of the foot and the fifth connecting rod (43). The axis of the fourth rotating pair is horizontally arranged and perpendicular to the front-back direction of the foot; a second spherical shell (52) for cooperating with a second sphere to form a second spherical hinge (36) is also installed at the upper end of the foot.

7. The parallel mechanical joint imitating human ankle movement according to claim 6, wherein: One end of the first push rod sleeve and the first driving motor are both installed at the bottom end of the first push rod base; the hinge ear provided at the top end of the first push rod base is engaged with the other end of the first connecting rod (11) through a hinge shaft to form a second rotating pair (21); the other end of the first push rod (25) is engaged with the other end of the fourth connecting rod (42) through a hinge shaft to form a third rotating pair (26).

8. The parallel mechanical joint imitating human ankle movement according to claim 7, characterized in that: One end of the second push rod sleeve and the second driving motor are both installed at the bottom end of the second push rod base; a first sphere that cooperates with the first spherical shell (12) to form a first spherical hinge (31) is provided at the top end of the second push rod base; the second push rod extends downward from the second electric push rod and a second sphere for cooperating with the second spherical shell 52 to form a second spherical hinge (36) is fixed at the end.

9. The parallel mechanical joint imitating human ankle movement according to claim 8, wherein: The axes of the first rotating pair (13), the second rotating pair (21), and the third rotating pair (26) are parallel to each other and perpendicular to the axis of the fourth rotating pair (51).

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