Five-degree-of-freedom hybrid robot

Abstract

The application discloses a five-degree-of-freedom hybrid robot, and relates to the technical field of robots, comprising a fixed platform, wherein the fixed platform is provided with first fixed supports and second fixed supports with axes perpendicular to each other, two first fixed supports are rotationally connected with a first rotating frame, the first rotating frame is sequentially provided with a first motion branch chain, a fourth motion branch chain and a second motion branch chain, the ends of the first motion branch chain and the second motion branch chain are symmetrically hinged to the opposite sides of a movable platform, the second fixed supports are rotationally connected with a second rotating frame, the second rotating frame is provided with a third motion branch chain, and the third motion branch chain and the fourth motion branch chain are respectively hinged to the other opposite sides of the movable platform through mutually perpendicular rotating pairs; and the bottom of the movable platform is provided with a two-degree-of-freedom double-pendulum head. The five-degree-of-freedom hybrid robot has the advantages of high rigidity, large rotation angle, high flexibility, large working space and the like, and can be used for the machining and manufacturing of complex parts.

Description

Technical Field

[0001] This invention relates to the field of robotics, and more particularly to a five-degree-of-freedom hybrid robot. Background Technology

[0002] In the field of friction stir welding, gantry-type friction stir welding equipment is commonly used for processing and manufacturing, but it is difficult to apply to complex curved structures. A five-degree-of-freedom hybrid robot with a three-degree-of-freedom parallel mechanism consisting of two rotations and one transfer is the main mechanism. It has the characteristics of high flexibility, high rigidity and large working space, providing a good solution for friction stir welding.

[0003] Currently, classic five-DOF hybrid robots, such as Exechon (WO2006054935), employ a 2UPR-SPR parallel mechanism with a two-DOF dual-swivel head, where the UPR branch provides two constraints. The Ecospeed horizontal five-axis machining center uses a 3-PRS Z3 spindle head (US6431802) as its main mechanism, connected to a two-DOF moving table to achieve five-axis linkage machining, where each branch of the Z3 spindle head provides one constraint. Chinese patent application CN201910059217.2 uses a 2UPU-SP two-rotation-one-transfer parallel mechanism with a two-DOF dual-swivel head, where the SP branch provides two constraints. All of these five-DOF hybrid robots are constructed using a three-branch configuration of a two-rotation-one-transfer three-DOF parallel mechanism as their main mechanism and are widely used in various light-load machining applications, such as drilling and milling. Compared to a parallel mechanism with four branches, two rotations, and one transfer, it still has shortcomings in terms of stiffness and load-bearing capacity.

[0004] Five-DOF hybrid robots such as Tricept (US4732525) and TriMule (CN201520494616.9) employ a four-branch, two-rotation, one-transfer parallel mechanism. Both consist of a two-DOF dual-swing head connected in series with this parallel mechanism. Tricept's parallel mechanism comprises three UPS branches and one UP branch. The UP branch provides two translational and one rotational constraints for the moving platform, and only the UP branch participates in resisting the forces acting on the moving platform. In TriMule's parallel section, the UPS branch is located at the rear, while the other three branches are in the front plane. Two of these branches can be configured as UPR or UPS, symmetrically arranged about the central UP branch. In this configuration, the load-bearing capacity primarily relies on the branches in the front plane.

[0005] In addition, many research units and scientific research institutions have developed various five-degree-of-freedom hybrid robots. However, five-degree-of-freedom hybrid robots with a four-branch, two-rotation, one-transfer parallel mechanism that has a spatial constraint force system, high stiffness, and balanced load bearing are still relatively few. Summary of the Invention

[0006] The purpose of this invention is to propose a five-degree-of-freedom hybrid robot with a spatial constraint force system, high stiffness, and balanced load-bearing capacity.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A five-degree-of-freedom hybrid robot includes a fixed platform. The fixed platform has a first fixed support and a second fixed support with mutually perpendicular axes. A first rotating frame is rotatably connected between the two first fixed supports. A first motion branch, a fourth motion branch, and a second motion branch are sequentially arranged on the first rotating frame. The ends of the first and second motion branches are symmetrically hinged to opposite sides of the moving platform. A second rotating frame is rotatably connected to the second fixed support. A third motion branch is arranged on the second rotating frame. The third and fourth motion branches are respectively hinged to other opposite sides of the moving platform with mutually perpendicular revolute joints. A two-degree-of-freedom double-swing head is provided at the bottom of the moving platform.

[0009] Furthermore, the first and second motion branches have the same structure and are symmetrically arranged on both sides of the fourth motion branch. The first, second, and fourth motion branches are coplanar and are all rotatably connected to the fixed platform through the first rotating frame. The axes formed by the first rotating frame and the fourth motion branch are parallel to each other. The axes formed by the first, second, and fourth motion branches and the first rotating frame are perpendicular to the axis formed by the first rotating frame and the first fixed support. The axes formed by the first rotating frame and the first fixed support, and the axes formed by the second rotating frame and the second fixed support are perpendicular to each other. The third motion branch is connected to the fixed platform through the second rotating frame.

[0010] Furthermore, the ends of the first and second motion chains are symmetrically connected to opposite sides of the moving platform via the first and second Hooke hinges, respectively, and the ends of the third and fourth motion chains are rotatably connected to the other opposite sides of the moving platform.

[0011] The first Hooke hinge is connected to the axis of the moving platform, the second Hooke hinge is connected to the axis of the moving platform, the rotation axis of the front end of the third motion branch connected to the moving platform is coplanar with the rotation axis of the front end of the fourth motion branch connected to the moving platform; the rotation axis of the third motion branch connected to the moving platform is perpendicular to the rotation axis of the fourth motion branch connected to the moving platform; the axis of the first Hooke hinge connected to the moving platform and the axis of the second Hooke hinge connected to the moving platform coincide, and are perpendicular to or coincide with the rotation axis of the front end of the fourth motion branch connected to the moving platform.

[0012] Furthermore, the first motion chain includes a first chain base, on which two parallel first guide rails are provided. A first slider is slidably connected to the first guide rails, and a first nut assembly is fixedly connected to the first slider. The first nut assembly cooperates with a first ball screw. One end of the first ball screw is connected to a first drive motor via a first coupling and cooperates with a first front bearing, while the other end is connected to a first tail bearing. Both the first drive motor and the first tail bearing are fixedly connected to the first chain base. The first nut assembly is connected to a first lug assembly, which is rotatably connected to a first rotating frame. A first Hooke hinge is provided at the end of the first chain base. The first Hooke hinge is rotatably connected to the moving platform via a first U-shaped member. The first Hooke hinge is connected to the axis of rotation of the first motion chain, which is parallel to the axis of rotation formed by the first motion chain and the first rotating frame.

[0013] Furthermore, the fourth motion branch includes a fourth branch base, on which two parallel fourth guide rails are provided. A fourth slider is slidably connected to the fourth guide rails. The fourth slider is provided with a fourth support lug assembly. The fourth support lug assembly is rotatably connected to the first rotating frame and rotatably connected to the fourth slider via a fourth bearing, and can rotate relative to the fourth branch itself. The end of the fourth branch base is rotatably connected to the moving platform via a rotating joint. The axis of the rotating joint is parallel or perpendicular to the axis formed by the fourth branch and the first rotating frame.

[0014] Furthermore, the third motion branch includes a third branch base, on which two parallel third guide rails are provided. A third slider is slidably connected to the third guide rails, and a third nut assembly is fixedly connected to the third slider. The third nut assembly is provided with a third ear assembly, which is rotatably connected to the second rotating frame and rotatably connected to the third slider through a third bearing, and can rotate relative to the third branch itself. The end of the third branch base is rotatably connected to the moving platform through a rotating pair, and its axis is coplanar and perpendicular to the rotation axis connecting the fourth motion branch and the moving platform.

[0015] Furthermore, the two-degree-of-freedom double pendulum head includes a first pendulum joint and a second pendulum joint arranged sequentially from top to bottom.

[0016] Beneficial effects

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] In the parallel section of this invention, each branch provides a constraint, and the four branches work together to resist the load, resulting in a more balanced load. Therefore, the five-degree-of-freedom hybrid robot of this invention is more likely to meet the needs of heavy-duty processing applications.

[0019] The parallel part of this invention is an over-constraint mechanism that connects two-degree-of-freedom double swing heads in series. The entire system has advantages such as high rigidity, large rotation angle, high flexibility, and large working space, and can be used for the processing and manufacturing of complex parts. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0021] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of the first kinematic branch in Embodiment 1 of the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of the second kinematic branch in Embodiment 1 of the present invention;

[0024] Figure 4 This is a schematic diagram of the third kinematic branch in Embodiment 1 of the present invention;

[0025] Figure 5 This is a schematic diagram of the fourth kinematic branch in Embodiment 1 of the present invention;

[0026] Figure 6 This is a schematic diagram of the two-degree-of-freedom double-swing head structure of the present invention;

[0027] Figure 7 This is a schematic diagram of the overall structure of Embodiment 2 of the present invention;

[0028] Figure 8 This is a schematic diagram of the third kinematic branch in Embodiment 2 of the present invention;

[0029] Figure 9 This is a schematic diagram of the fourth kinematic branch in Embodiment 2 of the present invention.

[0030] In the diagram: 1. First kinematic branch; 2. Second kinematic branch; 3. Third kinematic branch; 4. Fourth kinematic branch; 5. Fixed platform; 6. Moving platform; 7. First rotating frame; 8. First fixed support; 9. Second rotating frame; 10. Second fixed support; 11. Two-degree-of-freedom double pendulum head;

[0031] 1101, First swing joint; 1102, Second swing joint;

[0032] 101. First support chain base; 102. First drive motor; 103. First ball screw; 104. First coupling; 105. First nut assembly; 106. First guide rail; 107. First slider; 108. First lug assembly; 109. First Hooke hinge; 110. First U-shaped component; 111. First front bearing; 112. First tail bearing;

[0033] 201. Second branch base; 202. Second drive motor; 203. Second ball screw; 204. Second coupling; 205. Second nut assembly; 206. Second guide rail; 207. Second slider; 208. Second lug assembly; 209. Second Hooke hinge; 210. Second U-shaped component; 211. Second front bearing; 212. Second tail bearing;

[0034] 301. Third branch chain base; 302. Third drive motor; 303. Third ball screw; 304. Third coupling; 305. Third nut assembly; 306. Third guide rail; 307. Third slider; 308. Third lug assembly; 309. Third front bearing; 310. Third tail bearing; 311. Third middle bearing;

[0035] 401. Fourth branch base; 402. Fourth guide rail; 403. Fourth slider; 404. Connecting plate; 405. Fourth support lug assembly; 406. Fourth bearing. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0037] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] Example 1: Refer to Figures 1-6 ,

[0039] A five-degree-of-freedom hybrid robot includes a fixed platform 5, on which are mounted a first fixed support 8 and a second fixed support 10 with mutually perpendicular axes. A first rotating frame 7 is rotatably connected between the two first fixed supports 8. A first motion chain 1, a fourth motion chain 4, and a second motion chain 2 are sequentially mounted on the first rotating frame 7. The ends of the first motion chain 1 and the second motion chain 2 are symmetrically hinged to opposite sides of a moving platform 6 via Hooke's joints. A second rotating frame 9 is rotatably connected to the second fixed support 10. A third motion chain 3 is mounted on the second rotating frame 9. The third motion chain 3 and the fourth motion chain 4 are respectively hinged to the other opposite sides of the moving platform 6 via revolute joints with mutually perpendicular axes. A two-degree-of-freedom double-swivel head 11 is provided at the bottom of the moving platform 6.

[0040] The first motion branch 1 and the second motion branch 2 have the same structure and are symmetrically arranged on both sides of the fourth motion branch 4. The first motion branch 1, the second motion branch 2, and the fourth motion branch 4 are coplanar and rotatably connected to the fixed platform 5 via the first rotating frame 7, and their axes are parallel to each other. The axes formed by the first, second, and fourth motion branches (1, 2, 4) and the first rotating frame 7 are perpendicular to the axis formed by the first rotating frame 7 and the first fixed support 8. The third motion branch 3 is connected to the fixed platform 5 via the second rotating frame 9, and the axis formed by the third motion branch 3 and the second rotating frame 9 is perpendicular to the rotation axis of the second rotating frame 9 connected to the fixed platform 5. The axes formed by the first rotating frame 7 and the first fixed support 8, and the axes formed by the second rotating frame 9 and the second fixed support 10 are perpendicular to each other.

[0041] The ends of the first and second motion branches (1, 2) are symmetrically connected to opposite sides of the moving platform 6 via the first and second Hooke hinges (109, 209), respectively. The ends of the third and fourth motion branches (3, 4) are rotatably connected to the other opposite sides of the moving platform 6. The rotation axis of the first Hooke hinge 109 and the moving platform 6, the rotation axis of the second Hooke hinge 209 and the moving platform 6, the rotation axis of the front end of the third motion branch 3 connected to the moving platform 6, and the rotation axis of the front end of the fourth motion branch 4 connected to the moving platform 6 are coplanar. The axes of the first and second Hooke hinges (109, 209) connected to the branches are parallel to the axis of the fourth motion branch 4 connected to the moving platform 6. The axes of the first Hooke hinge 109 connected to the moving platform 6 and the axes of the second Hooke hinge 209 connected to the moving platform 6 coincide and are perpendicular to the rotation axis of the fourth motion branch 4 connected to the moving platform 6. The rotation axis connecting the third motion branch 3 and the moving platform 6 is perpendicular to the rotation axis connecting the fourth motion branch 4 and the moving platform 6, that is, parallel to the rotation axis connecting the first Hooke hinge 109 to the first motion branch 1.

[0042] In a preferred embodiment, the first motion chain 1 includes a first chain base 101, on which two parallel first guide rails 106 are provided. A first slider 107 is slidably connected to the first guide rails 106. A first screw nut assembly 105 is fixedly connected to the first slider 107. The first screw nut assembly 105 cooperates with a first ball screw 103. One end of the first ball screw 103 is connected to a first drive motor 102 through a first coupling 104 and cooperates with a first front bearing 111. The other end is connected to a first tail bearing 112. The first drive motor 102 and the first tail bearing 112 are both fixedly connected to the first chain base 101. The first screw nut assembly 105 is connected to a first support lug assembly 108, which is rotatably connected to a first rotating frame 7. A first Hooke's hinge 109 is provided at the end of the first branch base 101. The first Hooke's hinge 109 is realized by a first U-shaped member 110, wherein the U-shaped frame is rotatably connected to the front end of the first moving branch 1, and the short shaft portion outside the U-shaped frame is rotatably connected to the moving platform 6. The axis formed by the U-shaped frame connected to the front end of the first moving branch 1 is parallel to the axis formed by the first moving branch 1 connected to the first rotating frame 7, and is perpendicular to the moving direction of the first moving branch 1. The axis formed by the short shaft portion outside the U-shaped frame connected to the moving platform 6 is coplanar with the axis formed by the first rotating frame 7 connected to the first fixed support 8.

[0043] In a preferred embodiment, the fourth motion branch 4 includes a fourth branch base 401, on which two parallel fourth guide rails 402 are provided. A fourth slider 403 is slidably connected to the fourth guide rails 402, and the fourth slider 403 is provided with a fourth support assembly 405. The fourth support assembly 405 is rotatably connected to the first rotating frame 7 and rotatably connected to the fourth slider 403 via a fourth bearing 406, and can rotate relative to the fourth branch itself. The end of the fourth branch base 401 is rotatably connected to the moving platform 6 via a revolute joint. The axis of the revolute joint is parallel to the axis formed by the fourth branch and the first rotating frame 7, and perpendicular to the direction of movement of the fourth branch. The axis formed by the first rotating frame 7 connected to the first fixed support 8, the axis formed by the fourth support assembly 405 connected to the first rotating frame 7, and the axis of rotation formed by the fourth support assembly 405 connected to the fourth slider 403 are not coplanar but intersect at a point, forming a second ball joint.

[0044] In a preferred embodiment, the third motion branch 3 includes a third branch base 301, on which two parallel third guide rails 306 are provided. A third slider 307 is slidably connected to the third guide rails 306, and a third nut assembly 305 is fixedly connected to the third slider 307. The third nut assembly 305 is provided with a third ear assembly. The third ear assembly is rotatably connected to the second rotating frame 9 and rotatably connected to the third slider 307 via a third bearing, and can rotate relative to the third branch itself. The end of the third branch base 301 is rotatably connected to the moving platform 6 via a rotating joint. Its axis is coplanar and perpendicular to the rotation axis connecting the fourth motion branch 4 and the moving platform 6, and parallel to the axis of the first Hooke hinge 109 connected to the moving platform 6, and perpendicular to the direction of movement of the third branch. The axis formed by the second rotating frame 9 connected to the second fixed support 10, the axis formed by the third ear assembly connected to the second rotating frame 9, and the axis of rotation formed by the third ear assembly connected to the third nut assembly 305 are not coplanar but intersect at a point, forming a first ball joint.

[0045] In a preferred embodiment, the line connecting the center of the first ball joint and the center of the second ball joint intersects perpendicularly with the axis formed by the first rotating frame 7 and the first fixed support 8.

[0046] In a preferred embodiment, the two-degree-of-freedom double pendulum head 11 includes a first pendulum joint 1101 and a second pendulum joint 1102 arranged sequentially from top to bottom.

[0047] Example 2: Refer to Figure 7 - Figure 9 ,

[0048] Compared to Embodiment 1, the connection methods of the third motion branch 3 and the fourth motion branch 4 to the moving platform 6 differ: the first Hooke hinge 109 connected to the axis of the moving platform 6, the second Hooke hinge 209 connected to the axis of the moving platform 6, and the rotation axis of the fourth motion branch 4 connected to the moving platform 6 coincide. The rotation axis connecting the third motion branch 3 to the moving platform 6 remains perpendicular to the rotation axis connecting the fourth motion branch 4 to the moving platform 6, that is, perpendicular to the rotation axis connecting the first Hooke hinge 109 to the first motion branch 1.

[0049] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A five-degree-of-freedom hybrid robot, characterized in that, The system includes a fixed platform, on which are mounted a first fixed support and a second fixed support with mutually perpendicular axes. A first rotating frame is rotatably connected between the two first fixed supports. A first kinematic branch, a fourth kinematic branch, and a second kinematic branch are sequentially mounted on the first rotating frame. The ends of the first and second kinematic branches are symmetrically hinged to opposite sides of the moving platform. A second rotating frame is rotatably connected to the second fixed support, and a third kinematic branch is mounted on the second rotating frame. The third and fourth kinematic branches are respectively hinged to the other opposite sides of the moving platform with mutually perpendicular revolute joints. A two-degree-of-freedom double-swing head is provided at the bottom of the moving platform. The ends of the first and second motion chains are symmetrically connected to opposite sides of the moving platform via the first and second Hooke hinges, respectively, while the ends of the third and fourth motion chains are rotatably connected to the other opposite sides of the moving platform. The first Hooke hinge is connected to the axis of the moving platform, the second Hooke hinge is connected to the axis of the moving platform, the rotation axis of the front end of the third motion branch connected to the moving platform is coplanar with the rotation axis of the front end of the fourth motion branch connected to the moving platform; the rotation axis of the third motion branch connected to the moving platform is perpendicular to the rotation axis of the fourth motion branch connected to the moving platform; the axis of the first Hooke hinge connected to the moving platform and the axis of the second Hooke hinge connected to the moving platform coincide, and are perpendicular to or coincide with the rotation axis of the front end of the fourth motion branch connected to the moving platform.

2. The five-degree-of-freedom hybrid robot according to claim 1, characterized in that, The first and second motion branches have the same structure and are symmetrically arranged on both sides of the fourth motion branch. The first, second, and fourth motion branches are coplanar and are all rotatably connected to the fixed platform through the first rotating frame. The axes formed by the first rotating frame and the fourth motion branch are parallel to each other. The axes formed by the first, second, and fourth motion branches and the first rotating frame are perpendicular to the axis formed by the first rotating frame and the first fixed support. The axes formed by the first rotating frame and the first fixed support, and the axes formed by the second rotating frame and the second fixed support are perpendicular to each other. The third motion branch is connected to the fixed platform through the second rotating frame.

3. A five-degree-of-freedom hybrid robot according to any one of claims 1-2, characterized in that, The first motion chain includes a first chain base, on which two parallel first guide rails are provided. A first slider is slidably connected to the first guide rails, and a first nut assembly is fixedly connected to the first slider. The first nut assembly cooperates with a first ball screw. One end of the first ball screw is connected to a first drive motor via a first coupling and cooperates with a first front bearing, while the other end is connected to a first tail bearing. Both the first drive motor and the first tail bearing are fixedly connected to the first chain base. The first nut assembly is connected to a first lug assembly, which is rotatably connected to a first rotating frame. A first Hooke hinge is provided at the end of the first chain base. The first Hooke hinge is rotatably connected to the moving platform via a first U-shaped member. The first Hooke hinge is connected to the axis of rotation of the first motion chain, which is parallel to the axis of rotation formed by the first motion chain and the first rotating frame.

4. A five-degree-of-freedom hybrid robot according to any one of claims 1-2, characterized in that, The fourth motion branch includes a fourth branch base, on which two parallel fourth guide rails are provided. A fourth slider is slidably connected to the fourth guide rails. The fourth slider is provided with a fourth support lug assembly. The fourth support lug assembly is rotatably connected to the first rotating frame and rotatably connected to the fourth slider through a fourth bearing, and can rotate relative to the fourth branch itself. The end of the fourth branch base is rotatably connected to the moving platform through a rotating joint. The axis of the rotating joint is parallel or perpendicular to the axis formed by the fourth branch and the first rotating frame.

5. A five-degree-of-freedom hybrid robot according to any one of claims 1-2, characterized in that, The third motion branch includes a third branch base, on which two parallel third guide rails are provided. A third slider is slidably connected to the third guide rails. A third nut assembly is fixedly connected to the third slider. The third nut assembly is provided with a third ear assembly. The third ear assembly is rotatably connected to the second rotating frame and rotatably connected to the third slider through a third bearing. It can rotate relative to the third branch itself. The end of the third branch base is rotatably connected to the moving platform through a rotating pair. Its axis is coplanar and perpendicular to the rotation axis connecting the fourth motion branch and the moving platform.

6. A five-degree-of-freedom hybrid robot according to claim 1, characterized in that, The two-degree-of-freedom double pendulum head includes a first pendulum joint and a second pendulum joint arranged sequentially from top to bottom.

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