A compliant joint and robot hand for shaft-hole assembly

Abstract

The application provides a compliant joint and a manipulator for shaft hole assembly, and relates to the field of manipulators, and comprises a collar, a center block arranged at the center of the collar, flexible hinges arranged between the center block and the collar, two ends of the flexible hinges connected with the center block and the collar respectively, four flexible hinges orthogonally distributed on the center block, first thinning areas and second thinning areas formed on each flexible hinge, the first thinning areas and the second thinning areas alternately arranged in the length direction of the flexible hinge, a lower end plate coaxially arranged below the collar, flexible legs arranged between the lower end plate and the collar, two ends of the flexible legs connected with the collar and the lower end plate respectively, four flexible legs orthogonally arranged on the lower end plate, third thinning areas and fourth thinning areas formed on each flexible leg, the third thinning areas and the fourth thinning areas alternately arranged in the length direction of the flexible hinge, and the flexible hinges and the flexible legs made of rigid materials.

Description

Technical Field

[0001] This invention relates to the field of robotic arms, and particularly to a compliant joint and robotic arm for shaft-hole assembly. Background Technology

[0002] In shaft assembly operations, it is inevitable to use robotic arms for gripping and assembly. A robotic arm consists of a manipulator, rigid joints, actuators, and a control unit. The actuators are connected to the manipulator via rigid joints, and the control unit controls the movement and gripping of the manipulator and actuator to achieve precise control. However, while this control method can achieve high-precision movement, it cannot handle complex environments and uncertainties.

[0003] like Figure 1 The hole-shaft assembly process shown mainly includes four steps: First, the shaft, held by a robotic arm, gradually approaches the hole while adjusting its posture; second, the shaft contacts the chamfer of the hole; third, guided by the chamfer, the robotic arm performs a second posture adjustment of the shaft; fourth, once the shaft and hole are adjusted to the appropriate position, the robotic arm inserts the shaft into the hole to complete the assembly. In the second and third steps of hole-shaft assembly, because the existing manipulator uses rigid joints, it lacks tactile feedback and flexibility regarding the chamfer. This prevents the existing robotic arm from sensing the force exerted by the chamfer on the shaft through its mechanical structure, hindering real-time interaction with the assembly environment and causing malfunctions and damage to the robotic arm.

[0004] For the reasons mentioned above, this application provides a compliant joint suitable for shaft-hole assembly, which can adaptively adjust the assembly posture of the shaft through feedback from the assembly environment. Summary of the Invention

[0005] This invention provides a compliant joint and a robot for shaft hole assembly. Its purpose is to solve the problem that existing rigid joints cannot adaptively adjust the assembly posture according to the assembly environment when adjusting the posture of shaft parts, making it difficult to perform assembly compliantly.

[0006] To achieve the above objectives, embodiments of the present invention provide a compliant joint for shaft-hole assembly, comprising:

[0007] Ring;

[0008] A center block is located at the center of the collar. A flexible hinge is provided between the center block and the collar. The two ends of the flexible hinge are respectively connected to the center block and the collar. Four flexible hinges are orthogonally distributed on the center block. Each flexible hinge has a first thinning area recessed along the width direction of the flexible hinge and a second thinning area recessed along the thickness direction of the flexible hinge. The first thinning area and the second thinning area are alternately arranged along the length direction of the flexible hinge.

[0009] The lower end plate is coaxially disposed below the collar. A flexible support leg is disposed between the lower end plate and the collar. The two ends of the flexible support leg are respectively connected to the collar and the lower end plate. The four flexible support legs are orthogonally arranged on the lower end plate. Each flexible support leg has a third thinning area recessed along the width direction of the flexible support leg and a fourth thinning area recessed along the thickness direction of the flexible support leg. The third thinning area and the fourth thinning area are alternately disposed along the length direction of the flexible hinge.

[0010] The flexible hinge and the flexible leg are made of rigid material.

[0011] Preferably, the flexible hinge has one first thinning region and one second thinning region in the length direction, and the flexible leg has one third thinning region and one fourth thinning region in the length direction.

[0012] Preferably, the flexible hinge includes a first connecting plate, a second connecting plate, and a first intermediate plate. The first intermediate plate includes a first surface and a second surface facing each other. A first end of the first connecting plate is connected to a central block. A second end of the first connecting plate is perpendicularly connected to the first surface and forms a first thinning area with the first intermediate plate. A first end of the second connecting plate is perpendicularly connected to the second surface and forms a second thinning area with the first intermediate plate. A second end of the second connecting plate is connected to a collar. The projections of the first connecting plate and the second connecting plate on the first surface are perpendicular to each other.

[0013] The flexible support leg includes a third connecting plate, a fourth connecting plate, and a second intermediate plate. The second intermediate plate includes a third surface and a fourth surface facing each other. The first end of the third connecting plate is connected to a collar. The second end of the third connecting plate is perpendicularly connected to the third surface and forms a third thinning zone with the second intermediate plate. The first end of the fourth connecting plate is perpendicularly connected to the fourth surface and forms a fourth thinning zone with the second intermediate plate. The second end of the fourth connecting plate is connected to the lower end plate. The projections of the third connecting plate and the fourth connecting plate on the third surface are perpendicular to each other.

[0014] Preferably, the first connecting plate is perpendicular to the centerline of the first surface and forms two first thinning areas symmetrical about the first connecting plate, and the second connecting plate is perpendicular to the centerline of the second surface and forms two second thinning areas symmetrical about the second connecting plate.

[0015] The third connecting plate is perpendicular to the centerline of the third surface and forms two third thinning zones symmetrical about the third connecting plate. The fourth connecting plate is perpendicular to the centerline of the fourth surface and forms two fourth thinning zones symmetrical about the fourth connecting plate.

[0016] Preferably, the projection of the axis of the central block onto the first intermediate plate is perpendicular or parallel to the thickness direction of the first connecting plate.

[0017] Preferably, the compliant joint for shaft hole assembly further includes an upper end plate, which is disposed below the collar and connected to the flexible support leg.

[0018] Preferably, the compliant joint for shaft hole assembly further includes a connecting flange disposed on the center block.

[0019] This application also discloses a robotic arm employing the aforementioned compliant joint for shaft-hole assembly, further comprising a manipulator and an actuator for gripping parts, wherein the distal end of the manipulator is connected to the central block, and the actuator is connected to the lower end plate.

[0020] The above-described solution of the present invention has the following beneficial effects:

[0021] In this application, flexible hinges and flexible legs that can deform in two directions are respectively provided between the center block and the collar, and between the collar and the lower end plate, so that the compliant joint can achieve six degrees of freedom of movement. When the compliant joint is subjected to external force, the flexible hinges and / or flexible legs passively comply with the environmental resistance through deformation, thereby compensating for the small positional deviation between the shaft and the hole, so that the compliant joint has high flexibility and adaptability in complex assembly environments.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0023] Figure 1 This is a diagram showing the assembly steps of the shaft hole in existing technology;

[0024] Figure 2 This is a diagram illustrating a flexible joint;

[0025] Figure 3 This is a schematic diagram of a flexible hinge;

[0026] Figure 4 This is a schematic diagram of a flexible outrigger;

[0027] Figure 5 This is a schematic diagram of a robotic arm.

[0028] [Explanation of Labels in the Attached Image]

[0029] 1. Collar; 2. Center block; 3. Flexible hinge; 31. First thinning zone; 32. Second thinning zone; 33. First connecting plate; 34. Second connecting plate; 35. First intermediate plate; 4. Lower end plate; 5. Flexible support leg; 51. Third thinning zone; 52. Fourth thinning zone; 53. Third connecting plate; 54. Fourth connecting plate; 55. Second intermediate plate; 56. Pad plate; 6. Upper end plate; 7. Connecting flange; 8. Operating arm; 9. Actuator; A. Compliant joint. Detailed Implementation

[0030] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0031] This application constructs a world coordinate system (XYZ) with compliant joint A, and constructs length, width and height coordinate systems for flexible hinge 3 and flexible support 5 respectively.

[0032] This invention addresses existing problems by providing a compliant joint for shaft-hole assembly, as described above. Figure 2-4 As shown, the device includes a collar 1, a central block 2, and a lower end plate 4. The central block 2 is located at the center of the collar 1, and a flexible hinge 3 is provided between the central block 2 and the collar 1. One end of the flexible hinge 3 is connected to the side of the central block 2, and the other end is connected to the inner wall of the collar 1. Four flexible hinges 3 are orthogonally distributed on the central block 2. In this application, the four flexible hinges 3 are distributed along the X-axis and Y-axis directions, respectively. A first thinning region 31 and a second thinning region 32 are formed on each flexible hinge 3. The first thinning region 31 is recessed along the width direction of the flexible hinge 3, and the second thinning region 32 is recessed along the thickness direction of the flexible hinge 3. The first thinning region 31 and the second thinning region 32 are alternately arranged along the length direction of the flexible hinge 3.

[0033] The aforementioned lower end plate 4 is disposed below the collar 1 and is coaxially arranged with the collar 1. A flexible support leg 5 is provided between the lower end plate 4 and the collar 1. The length direction of the flexible support leg 5 is the same as the Z-axis direction. One end of the flexible support leg 5 is connected to the bottom surface of the collar 1, and the other end is connected to the top surface of the lower end plate 4. Four flexible support legs 5 are orthogonally arranged on the lower end plate 4. A third thinning region 51 and a fourth thinning region 52 are formed on each flexible support leg 5. The third thinning region 51 is recessed along the width direction of the flexible support leg 5, and the fourth thinning region 52 is recessed along the thickness direction of the flexible hinge 3. The third thinning region 51 and the fourth thinning region 52 are alternately arranged along the length direction of the flexible support leg 5.

[0034] The aforementioned flexible hinge 3 and flexible support leg 5 are made of rigid material. Preferably, the compliant joint is made of PTU material.

[0035] Typically, the compliant joint A is used to assemble between the distal end of the manipulator 8 and the actuator 9. The actuator 9 is used to grip the part, and the manipulator 8 is used to move the part to the assembly position for shaft-hole assembly. The reaction force of the chamfer on the shaft is transmitted to the compliant joint A through the actuator 9. The flexible hinge 3 and / or the flexible support leg 5 deform, giving the compliant joint A a certain degree of self-adaptability. It passively complies with the resistance of the chamfer, compensates for the positional deviation between the shaft and the hole, and achieves high-precision compliant assembly of the shaft and hole.

[0036] Specifically, when the compliant joint A is subjected to force, the first thinning region 31, the second thinning region 32, the third thinning region 51, and the fourth thinning region 52 will deform first relative to the non-thinning region of the flexible hinge 3, and relative to the non-thinning region of the flexible support leg 5. This allows each flexible hinge 3 and flexible support leg 5 to deform in two directions. Under the combined action of the flexible hinge 3 and flexible support leg 5, the shaft can move in six degrees of freedom. Furthermore, the force on the compliant joint A originates from the interaction force between the shaft and the hole. At the same time, the flexible hinge 3 and flexible support leg 5 are made of rigid materials, which limits the deformation of the first thinning region 31, the second thinning region 32, the third thinning region 51, and the fourth thinning region 52. This satisfies the requirement of passively conforming to environmental resistance during assembly, compensating for minor positional deviations between the shaft and the hole, while preventing the rigidity of the flexible hinge 3 and flexible support leg 5 from having an excessive impact.

[0037] In this application, multiple thinning regions 31, 32, 51 and 52 may be provided. Considering the rigidity of the flexible hinge 3 and the flexible leg 5, in this embodiment, the flexible hinge 3 is provided with a first thinning region 31 and a second thinning region 32 in the length direction of the flexible hinge 3, and the flexible leg 5 is provided with a third thinning region 51 and a fourth thinning region 52 in the length direction of the flexible leg 5.

[0038] Reference Figure 3 The flexible hinge 3 includes a first connecting plate 33, a second connecting plate 34, and a first intermediate plate 35. The first intermediate plate 35 has a first surface and a second surface, which are arranged opposite to each other. The first end of the first connecting plate 33 is connected to the side of the center block 2. The second end of the second connecting plate 34 is perpendicularly connected to the first surface and forms a first thinning region 31 on the first intermediate plate 35. The first end of the second connecting plate 34 is perpendicularly connected to the second surface and forms a second thinning region 32 on the first intermediate plate 35. The second end of the second connecting plate 34 is connected to the inner wall of the collar 1. The projections of the first connecting plate 33 and the second connecting plate 34 on the first surface are perpendicular to each other.

[0039] Furthermore, the first connecting plate 33 is perpendicular to the center line of the first surface and forms two first thinning regions 31 symmetrical about the first connecting plate 33, and the second connecting plate 34 is perpendicular to the center line of the second surface and forms two second thinning regions 32 symmetrical about the second connecting plate 34.

[0040] Reference Figure 4The flexible support leg 5 includes a third connecting plate 53, a fourth connecting plate 54, and a second intermediate plate 55. The second intermediate plate 55 has a third surface and a fourth surface. The first end of the third connecting plate 53 is connected to the bottom surface of the collar 1. The second end of the third connecting plate 53 is perpendicularly connected to the third surface and forms a third thinning region 51 with the second intermediate plate 55. The first end of the fourth connecting plate 54 is perpendicularly connected to the fourth surface and forms a fourth thinning region 52 with the second intermediate plate 55. The second end of the fourth connecting plate 54 is connected to the lower end plate 4. The projections of the third connecting plate 53 and the fourth connecting plate 54 on the third surface are perpendicular to each other.

[0041] Furthermore, the third connecting plate 53 is perpendicular to the center line of the third surface and forms two third thinning regions 51 symmetrical about the third connecting plate 53, and the fourth connecting plate 54 is perpendicular to the center line of the fourth surface and forms two fourth thinning regions 52 symmetrical about the fourth connecting plate 54.

[0042] Furthermore, the projection of the axis of the center block 2 onto the first connecting plate 33 is perpendicular or parallel to the thickness direction of the first connecting plate 33.

[0043] Preferably, a pad 56 perpendicular to the third connecting plate 53 and the fourth connecting plate 54 is welded to the first end of the third connecting plate 53 and the second end of the fourth connecting plate 54, respectively. The pad 56 is detachably connected to the lower end plate 4 and the collar 1.

[0044] Preferably, an upper end plate 6 with the same shape as the collar 1 is provided below the collar 1, and a pad 56 is connected to the upper end plate 6. The flexible support leg 5 and the collar 1 are fixed through the pad 56 and the upper end plate 6.

[0045] Preferably, the compliant joint for shaft hole assembly further includes a connecting flange 7, which is detachably mounted on the center block 2.

[0046] Reference Figure 5 This application also provides a robotic arm that utilizes the aforementioned compliant joint A, and further includes an operating arm 8 and an actuator 9. The distal end of the operating arm 8 is connected to the center block 2 via a connecting flange 7, and the actuator 9 is connected to the lower end plate 4.

[0047] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A compliant joint for shaft-hole assembly, characterized by, The utility model relates to a kind of flexible hinge and flexible support leg, comprising: A collar (1); Center block (2) is arranged in the center of the collar (1), and flexible hinge (3) is arranged between the center block (2) and the collar (1), two ends of the flexible hinge (3) are connected with the center block (2) and the collar (1) respectively, and four flexible hinges (3) are orthogonally distributed on the center block (2), first thinning area (31) is formed on each flexible hinge (3) along the width direction of flexible hinge (3) recessed, and second thinning area (32) is formed along the thickness direction of flexible hinge (3) recessed, first thinning area (31) and second thinning area (32) are alternately arranged in the length direction of the flexible hinge (3); Lower end plate (4) is coaxially arranged below the collar (1), and flexible support leg (5) is arranged between the lower end plate (4) and the collar (1), two ends of the flexible support leg (5) are connected with the collar (1) and the lower end plate (4) respectively, and four flexible support legs (5) are orthogonally arranged on the lower end plate (4), third thinning area (51) is formed on each flexible support leg (5) along the width direction of flexible support leg (5) recessed, and fourth thinning area (52) is formed along the thickness direction of flexible support leg (5) recessed, third thinning area (51) and fourth thinning area (52) are alternately arranged in the length direction of the flexible hinge (3); The flexible hinge (3) and the flexible support leg (5) are made of rigid material.

2. The compliant joint for shaft-hole assembly of claim 1, wherein: The first thinning area (31) and the second thinning area (32) in the length direction of the flexible hinge (3) are one respectively, and the third thinning area (51) and the fourth thinning area (52) in the length direction of the flexible support leg (5) are one respectively.

3. The compliant joint for shaft-hole assembly of claim 1, wherein: The flexible hinge (3) includes first connecting plate (33), second connecting plate (34) and first intermediate plate (35), the first intermediate plate (35) includes opposite first face and second face, the first end of the first connecting plate (33) is connected with the center block (2), the second end of the first connecting plate (33) is connected with the first face perpendicularly and forms the first thinning area (31) with the first intermediate plate (35), the first end of the second connecting plate (34) is connected with the second face perpendicularly and forms the second thinning area (32) with the first intermediate plate (35), the second end of the second connecting plate (34) is connected with the collar (1), and the projection of the first connecting plate (33) and the second connecting plate (34) on the first face is perpendicular to each other. The flexible support leg (5) includes a third connecting plate (53), a fourth connecting plate (54), and a second intermediate plate (55). The second intermediate plate (55) includes a third surface and a fourth surface facing each other. The first end of the third connecting plate (53) is connected to the collar (1). The second end of the third connecting plate (53) is perpendicularly connected to the third surface and forms a third thinning area (51) with the second intermediate plate (55). The first end of the fourth connecting plate (54) is perpendicularly connected to the fourth surface and forms a fourth thinning area (52) with the second intermediate plate (55). The second end of the fourth connecting plate (54) is connected to the lower end plate (4). The projections of the third connecting plate (53) and the fourth connecting plate (54) on the third surface are perpendicular to each other.

4. The compliant joint for shaft-hole assembly of claim 3, wherein: The first connecting plate (33) is perpendicular to the centerline of the first surface and forms two first thinning regions (31) symmetrical about the first connecting plate (33). The two connecting plates (34) are perpendicular to the centerline of the second surface and form two second thinning zones (32) that are symmetrical about the second connecting plate (34); The third connecting plate (53) is perpendicular to the center line of the third surface and forms two third thinning regions (51) symmetrical about the third connecting plate (53). The fourth connecting plate (54) is perpendicular to the center line of the fourth surface and forms two fourth thinning regions (52) symmetrical about the fourth connecting plate (54).

5. The compliant joint for shaft-hole assembly of claim 3, wherein: The projection of the axis of the central block (2) onto the first intermediate plate (35) is perpendicular or parallel to the thickness direction of the first connecting plate (33).

6. The compliant joint for shaft-hole assembly of claim 1, wherein: The compliant joint (A) for shaft hole assembly also includes an upper end plate (6), which is disposed below the collar (1) and connected to the flexible leg (5).

7. The compliant joint for shaft-hole assembly of claim 1, wherein: The compliant joint (A) for shaft hole assembly also includes a connecting flange (7) disposed on the center block (2).

8. A robot employing the compliant joint for shaft-hole assembly according to any one of claims 1 to 7, characterized by, It also includes an operating arm (8) and an actuator (9) for gripping parts, the distal end of the operating arm (8) being connected to the center block (2) and the actuator (9) being connected to the lower end plate (4).

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