A new five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation

Abstract

This invention provides a novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation, belonging to the technical field of five-degree-of-freedom parallel mechanisms. It includes a motion platform, a first branch, a universal joint assembly, a ball joint assembly, two transverse linear modules, two revolute joint assemblies, two second branches, and two Hooke hinges. The telescopic end of the first branch is fixedly connected to the side of the motion platform via the ball joint assembly, and the fixed end of the first branch is connected to the universal joint assembly. The telescopic ends of both second branches are connected to Hooke hinges, and the fixed ends of both second branches are connected to the transverse linear modules via the revolute joint assemblies. The two transverse linear modules are arranged in parallel, and the telescopic ends of the two second branches are respectively fixedly connected to the bottom of the motion platform via Hooke hinges. This invention not only has a simple structure, but also ensures that the motion platform plane always has only a transverse couple, guaranteeing stable three-dimensional spatial movement and vertical and longitudinal rotational motion across the entire omnidirectional range.

Description

Technical Field

[0001] This invention relates to the field of five-degree-of-freedom parallel mechanism technology, and in particular to a novel five-degree-of-freedom parallel mechanism capable of realizing three-dimensional translation and two-dimensional rotation. Background Technology

[0002] Parallel mechanisms, characterized by multi-closed-loop structures, achieve end-effector motion output through the coordinated action of multiple kinematic chains, complementing traditional mechanisms. Compared to serial mechanisms, parallel mechanisms offer advantages such as lower cumulative error, higher precision, better dynamic response, compact structure, high rigidity, and greater load-bearing capacity, attracting widespread research attention. Low-DOF parallel mechanisms, defined as those with fewer than 6 degrees of freedom, are applicable to many tasks suitable for parallel operation but not requiring all 6 degrees of freedom, such as surface machining, welding, cutting, and assembly. These mechanisms require at least 5 spatial degrees of freedom for the robot's end effector. Compared to 6-DOF parallel mechanisms, low-DOF parallel mechanisms offer advantages such as fewer driving components, fewer parts, simpler and more convenient control, easier manufacturing, and lower cost.

[0003] There are currently two main structures for parallel mechanisms with few degrees of freedom. One type involves installing an AC oscillating head on the motion platform of the parallel mechanism to achieve 5 degrees of freedom motion (two rotations and three translations). However, because the attitude adjustment of this structure is the composite motion of two series-connected oscillating axes, there are poles within the attitude workspace, and the pole attitudes correspond to multiple sets of inverse solutions. Due to the limitations of its own structure, the tool needs to pause the feed to prioritize attitude adjustment, or move along an inverted conical path to avoid the poles, reducing attitude adjustment efficiency and even scratching the part surface. The other type combines a constrained branch of the 5 degrees of freedom (two rotations and three translations) with an unconstrained branch, resulting in a more complex structure. Summary of the Invention

[0004] The purpose of this invention is to provide a novel five-degree-of-freedom parallel mechanism that can realize three-dimensional translation and two-dimensional rotation. It is not only simple in structure, but also ensures that the motion platform plane always has only a lateral couple, thus ensuring that the motion platform can achieve stable three-dimensional spatial movement and vertical and longitudinal rotational movements in all directions.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation includes a motion platform, a first branch, a universal joint assembly, a ball joint assembly, two transverse linear modules, two revolute joint assemblies, two second branches, and two Hooke hinges. The telescopic end of the first branch is fixedly connected to the side of the motion platform via the ball joint assembly, and the fixed end of the first branch is connected to the universal joint assembly. The telescopic ends of the two second branches are each connected to a Hooke hinge, and the fixed ends of the two second branches are each connected to a transverse linear module via the revolute joint assembly. The two transverse linear modules are arranged in parallel, and the telescopic ends of the two second branches are respectively fixedly connected to the bottom of the motion platform via Hooke hinges.

[0006] Furthermore, the first branch includes an optical shaft seat, a gearbox assembly, a lead screw, a nut, a positioning ring, an optical shaft, and an end cap. The gearbox assembly includes a gearbox housing, a gearbox end cap, a large wheel, a small wheel, a belt, a wheel axle, a bearing, a bearing seat, and a bearing seat nut.

[0007] The small wheel is externally connected to a servo motor and forms a belt drive with the large wheel. The large wheel is fixedly connected to the axle by set screws. The bearing housing is connected between the gearbox end cover and the optical shaft seat by screws. The bearing housing is sleeved on the axle, and the bearing is set between the bearing housing and the axle. The axle, bearing, and bearing housing are coaxial. A bearing housing nut is provided at one end of the bearing housing to limit the axial movement of the bearing and fix it. The gearbox outer shell is fixedly connected to the gearbox end cover. This device is used to encapsulate large wheels, small wheels, belts, and axles. The lead screw is fixedly connected to the axle by screws. The lead screw and the axle are coaxial. The bearing seat nut is sleeved on the outside of the lead screw. The lead screw and the nut form a helical transmission pair. The nut is sleeved on the lead screw and moves along the lead screw axis. The nut is fixedly connected to the optical shaft by a positioning ring. The end cover is sleeved on the outside of the optical shaft and fixed to one end of the optical shaft seat by screws. The optical shaft seat seals the internal positioning ring, nut, and lead screw. The optical shaft, the optical shaft seat, and the gearbox assembly form a sliding pair.

[0008] Furthermore, the universal joint assembly includes a first double-ear seat, a first rotating shaft, and a second double-ear seat. The first double-ear seat is connected to the second double-ear seat via the first rotating shaft to form a universal joint. The first double-ear seat is connected to the gearbox housing.

[0009] Furthermore, the ball joint assembly is a ball hinge, the ball joint assembly includes a ball seat and a ball head, the ball seat is disposed at the bottom of the ball head, the ball joint assembly is threadedly connected to the bottom of the optical bar through the ball seat, and the ball joint assembly is fixedly connected to the side of the motion platform through the ball head.

[0010] Furthermore, the transverse linear module includes a first profile, a first motor support, a first ball screw, a first slide, and a first ball screw support plate. The first ball screw is disposed inside the first profile. The first motor support is connected to one end of the first profile. A first motor is disposed inside the first motor support. The first motor is drivenly connected to one end of the first ball screw. The other end of the first ball screw is connected to the first ball screw support plate. A first slide is sleeved and connected to the first ball screw near the first ball screw support plate.

[0011] Furthermore, the rotating joint assembly includes a double-ear seat, a single-ear seat, and a rotating shaft. The single-ear seat is connected to the double-ear seat via the rotating shaft to form a rotating joint. The fixed ends of the two second branches are both connected to the surface of the first slide via the double-ear seat.

[0012] Furthermore, the Hooke hinge includes a first shaft end coupling, a slotted shaft, a second shaft end coupling, and a universal joint connector. The first shaft end coupling and the second shaft end coupling are connected by the slotted shaft to achieve relative movement. The second shaft end coupling is connected to the universal joint connector and maintains a coaxial rotational relationship. The telescopic ends of the two second branches are both connected to the Hooke hinge through the first shaft end coupling. The universal joint connector is fixed to the bottom of the motion platform by screws. The rotation center axis of the Hooke hinge is parallel to the rotation center axis of the rotating pair assembly.

[0013] Furthermore, both the first branch and the two second branches are electric actuators.

[0014] Furthermore, the motion platform has a cuboid structure.

[0015] Advantages of this invention: This invention adopts the concept of a few-degree-of-freedom branch plus an unconstrained branch. The few-degree-of-freedom branch uses a single-degree-of-freedom prismatic joint plus a four-degree-of-freedom closed-loop structure with two rotations and two translations to achieve the requirement of a five-degree-of-freedom constrained branch with two rotations and three translations. This ensures that the motion platform plane always has only a lateral couple, thus ensuring that the motion platform can achieve stable two-rotation and three-translation motion in all directions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the structure of the first branch in this invention.

[0018] Figure 3 This is a schematic diagram of the internal structure and lead screw connection of the gearbox assembly in this invention.

[0019] Figure 4 This is a schematic diagram of the connection structure between the wheel axle and the bearing in this invention.

[0020] Figure 5 This is a schematic diagram of the universal joint component in this invention.

[0021] Figure 6 This is a schematic diagram of the structure of the horizontal linear module in this invention.

[0022] Figure 7 This is a schematic diagram of the rotating pair assembly in this invention.

[0023] Figure 8 This is a schematic diagram of the connection structure between the second branch, the rotating pair assembly, and the Hooke's hinge in this invention.

[0024] Figure 9 This is a schematic diagram of the Hooke's hinge in this invention.

[0025] In the diagram: 1. Motion platform; 2. First branch chain; 21. Optical shaft seat; 22. Gearbox assembly; 221. Gearbox housing; 222. Gearbox end cover; 223. Large wheel; 224. Small wheel; 225. Belt; 226. Axle; 227. Bearing; 228. Bearing seat; 229. Bearing seat nut; 23. Lead screw; 24. Nut; 25. Positioning ring; 26. Optical shaft; 27. End cover; 3. Universal joint assembly; 31. First double-ear seat; 32. First rotating shaft; 33. The... 4. Ball joint assembly, 41. Ball seat, 42. Ball head, 5. Transverse linear module, 51. First profile, 52. First motor support seat, 53. First ball screw, 54. First slide, 55. First ball screw support plate, 6. Rotary joint assembly, 61. Double ear seat, 62. Single ear seat, 63. Rotating shaft, 7. Second branch, 8. Hooke hinge, 801. First shaft end coupling, 802. Slotted shaft, 803. Second shaft end coupling, 804. Universal joint connector. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0027] like Figure 1As shown, a novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation includes a motion platform 1, a first branch 2, a universal joint assembly 3, a ball joint assembly 4, two transverse linear modules 5, two revolute joint assemblies 6, two second branches 7, and two Hooke hinges 8. The telescopic end of the first branch 2 is fixedly connected to the side of the motion platform 1 through the ball joint assembly 4. The fixed end of the first branch 2 is connected to the universal joint assembly 3. The telescopic ends of the two second branches 7 are each connected to the Hooke hinges 8. The fixed ends of the two second branches 7 are each connected to the transverse linear modules 5 through the revolute joint assemblies 6. The two transverse linear modules 5 are arranged in parallel. The telescopic ends of the two second branches 7 are respectively fixedly connected to the bottom of the motion platform 1 through the Hooke hinges 8.

[0028] As a preferred embodiment of the present invention, such as Figures 2-4 As shown, the first branch 2 includes an optical shaft seat 21, a gearbox assembly 22, a lead screw 23, a nut 24, a positioning ring 25, an optical shaft 26, and an end cap 27. The gearbox assembly 22 includes a gearbox housing 221, a gearbox end cap 222, a large wheel 223, a small wheel 224, a belt 225, a wheel axle 226, a bearing 227, a bearing seat 228, and a bearing seat nut 229.

[0029] The small wheel 224 is externally connected to a servo motor and forms a belt drive with the large wheel 223 via a belt 225. The large wheel 223 is fixedly connected to the axle 226 by a set screw. The bearing housing 228 is connected between the gearbox end cover 222 and the optical shaft seat 21 by screws. The bearing housing 228 is sleeved on the axle 226. The bearing 227 is disposed between the bearing housing 228 and the axle 226. The axle 226, bearing 227, and bearing housing 228 are coaxial. A bearing housing nut 229 is provided at one end of the bearing housing 228. The bearing housing nut 229 is used to limit the axial movement of the bearing 227 and fix it. The gearbox housing 221 is fixedly connected to the gearbox end cover 222. 221 is used to encapsulate the large wheel 223, the small wheel 224, the belt 225, and the axle 226. The lead screw 23 is fixedly connected to the axle 226 by screws. The lead screw 23 and the axle 226 are coaxial. The bearing seat nut 229 is sleeved on the outside of the lead screw 23. The lead screw 23 and the nut 24 form a helical transmission pair. The nut 24 is sleeved on the lead screw 23 and moves along the axial direction of the lead screw 23. The nut 24 is fixedly connected to the optical shaft 26 by a positioning ring 25. The end cover 27 is sleeved on the outside of the optical shaft 26 and fixed to one end of the optical shaft seat 21 by screws. The optical shaft seat 21 seals the internal positioning ring 25, nut 24, and lead screw 23. The optical shaft 26, the optical shaft seat 21, and the gearbox assembly 22 form a sliding pair.

[0030] As a preferred embodiment of the present invention, such as Figure 5As shown, the universal joint assembly 3 includes a first double-ear seat 31, a first rotating shaft 32, and a second double-ear seat 33. The first double-ear seat 31 is connected to the second double-ear seat 33 through the first rotating shaft 32 to form a universal joint. The first double-ear seat 31 is connected to the gearbox housing 221.

[0031] As a preferred embodiment of the present invention, such as Figure 2 As shown, the ball joint assembly 4 is a ball hinge. The ball joint assembly 4 includes a ball seat 41 and a ball head 42. The ball seat 41 is located at the bottom of the ball head 42. The ball joint assembly 4 is threadedly connected to the bottom of the light bar 26 through the ball seat 41. The ball joint assembly 4 is fixedly connected to the side of the motion platform 1 through the ball head 42.

[0032] As a preferred embodiment of the present invention, such as Figure 6 As shown, the transverse linear module 5 includes a first profile 51, a first motor support 52, a first ball screw 53, a first slide 54, and a first ball screw support plate 55. The first ball screw 53 is disposed inside the first profile 51. The first motor support 52 is connected to one end of the first profile 51. A first motor is disposed inside the first motor support 52. The first motor is drivenly connected to one end of the first ball screw 53. The other end of the first ball screw 53 is connected to the first ball screw support plate 55. The first slide 54 is sleeved and connected to the first ball screw 53 near the first ball screw support plate 55.

[0033] As a preferred embodiment of the present invention, such as Figure 7 As shown, the rotary joint assembly 6 is a rotary joint. The rotary joint assembly 6 includes a double-ear seat 61, a single-ear seat 62, and a rotating shaft 63. The single-ear seat 62 is connected to the double-ear seat 61 through the rotating shaft 63 to form a rotary joint. The fixed ends of the two second branches 7 are both connected to the upper surface of the first slide table 54 through the double-ear seat 61.

[0034] As a preferred embodiment of the present invention, such as Figure 8 and Figure 9 As shown, the Hooke hinge 8 includes a first shaft end coupling 801, a slotted shaft 802, a second shaft end coupling 803, and a universal joint connector 804. The first shaft end coupling 801 and the second shaft end coupling 803 are connected by the slotted shaft 802 to achieve relative movement. The second shaft end coupling 803 is connected to the universal joint connector 804 and maintains a coaxial rotational relationship. The telescopic ends of the two second branches 7 are connected to the Hooke hinge 8 through the first shaft end coupling 801. The universal joint connector 804 is fixed to the bottom of the motion platform 1 by screws. The rotation center axis of the Hooke hinge 8 is parallel to the rotation center axis of the rotating pair assembly 6.

[0035] In a preferred embodiment of the present invention, the first branch 2 and the two second branches 7 are both electric push rods, and the structure of the two second branches 7 is the same as that of the first branch 2, which will not be described in detail here.

[0036] In a preferred embodiment of the present invention, the motion platform 1 is a cuboid structure.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can still adjust the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Therefore, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation, characterized in that: The system includes a motion platform (1), a first branch (2), a universal joint assembly (3), a ball joint assembly (4), two transverse linear modules (5), two rotary joint assemblies (6), two second branches (7), and two Hooke hinges (8). The telescopic end of the first branch (2) is fixedly connected to the side of the motion platform (1) through the ball joint assembly (4). The fixed end of the first branch (2) is connected to the universal joint assembly (3). The telescopic ends of the two second branches (7) are connected to the Hooke hinges (8). The fixed ends of the two second branches (7) are connected to the transverse linear modules (5) through the rotary joint assembly (6). The two transverse linear modules (5) are arranged in parallel. The telescopic ends of the two second branches (7) are fixedly connected to the bottom of the motion platform (1) through the Hooke hinges (8).

2. The novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation according to claim 1, characterized in that: The first branch (2) includes an optical shaft seat (21), a gearbox assembly (22), a lead screw (23), a nut (24), a positioning ring (25), an optical shaft (26), and an end cap (27). The gearbox assembly (22) includes a gearbox housing (221), a gearbox end cap (222), a large wheel (223), a small wheel (224), a belt (225), a wheel axle (226), a bearing (227), a bearing seat (228), and a bearing seat nut (229). The small wheel (224) is connected to an external servo motor and forms a belt drive with the large wheel (223) via a belt (225). The large wheel (223) is fixedly connected to the axle (226) by a set screw. The bearing seat (228) is connected between the gearbox end cover (222) and the optical shaft seat (21) by screws. The bearing seat (228) is sleeved on the axle (226). The bearing (227) is set between the bearing seat (228) and the axle (226). The axle (226), bearing (227) and bearing seat (228) are coaxial. One end of the bearing seat (228) is provided with a bearing seat nut (229). The bearing seat nut (229) is used to limit the axial movement of the bearing (227) and fix it. The gearbox outer shell (221) is fixedly connected to the gearbox end cover (222). The gearbox outer shell (221) is used to... The package includes a large wheel (223), a small wheel (224), a belt (225), and a wheel axle (226). The lead screw (23) is fixedly connected to the wheel axle (226) by screws. The lead screw (23) and the wheel axle (226) are coaxial. The bearing seat nut (229) is sleeved on the outside of the lead screw (23). The lead screw (23) and the nut (24) form a helical transmission pair. The nut (24) is sleeved on the lead screw (23) and moves along the axial direction of the lead screw (23). The nut (24) is fixedly connected to the optical shaft (26) by a positioning ring (25). The end cap (27) is sleeved on the outside of the optical shaft (26) and fixed to one end of the optical shaft seat (21) by screws. The optical shaft seat (21) seals the internal positioning ring (25), nut (24), and lead screw (23). The optical shaft (26), the optical shaft seat (21), and the gearbox assembly (22) form a sliding pair.

3. A novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation according to claim 2, characterized in that: The universal joint assembly (3) includes a first double-ear seat (31), a first rotating shaft (32), and a second double-ear seat (33). The first double-ear seat (31) is connected to the second double-ear seat (33) through the first rotating shaft (32) to form a universal joint. The first double-ear seat (31) is connected to the gearbox housing (221).

4. A novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation according to claim 3, characterized in that: The ball joint assembly (4) is a ball hinge. The ball joint assembly (4) includes a ball seat (41) and a ball head (42). The ball seat (41) is located at the bottom of the ball head (42). The ball joint assembly (4) is threaded to the bottom of the light bar (26) through the ball seat (41). The ball joint assembly (4) is fixedly connected to the side of the motion platform (1) through the ball head (42).

5. A novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation according to claim 4, characterized in that: The transverse linear module (5) includes a first profile (51), a first motor support (52), a first ball screw (53), a first slide (54), and a first ball screw support plate (55). The first ball screw (53) is disposed inside the first profile (51). The first motor support (52) is connected to one end of the first profile (51). A first motor is disposed inside the first motor support (52). The first motor is connected to one end of the first ball screw (53) for transmission. The other end of the first ball screw (53) is connected to the first ball screw support plate (55). The first slide (54) is sleeved and connected to the first ball screw (53) near the first ball screw support plate (55).

6. A novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation according to claim 5, characterized in that: The rotating joint assembly (6) includes a double ear seat (61), a single ear seat (62) and a rotating shaft (63). The single ear seat (62) is connected to the double ear seat (61) through the rotating shaft (63) to form a rotating joint. The fixed ends of the two second branches (7) are connected to the upper surface of the first slide (54) through the double ear seat (61).

7. A novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation according to claim 6, characterized in that: The Hooke hinge (8) includes a first shaft end coupling (801), a slotted shaft (802), a second shaft end coupling (803), and a universal joint connector (804). The first shaft end coupling (801) and the second shaft end coupling (803) are connected by the slotted shaft (802) to achieve relative movement. The second shaft end coupling (803) is connected to the universal joint connector (804) and maintains a coaxial rotational relationship. The telescopic ends of the two second branches (7) are connected to the Hooke hinge (8) through the first shaft end coupling (801). The universal joint connector (804) is fixed to the bottom of the motion platform (1) by screws. The rotation center axis of the Hooke hinge (8) is parallel to the rotation center axis of the rotating pair assembly (6).

8. A novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation according to claim 7, characterized in that: The first branch (2) and the two second branches (7) are all electric actuators.

9. A novel five-degree-of-freedom parallel mechanism capable of three-dimensional translation and two-dimensional rotation according to claim 8, characterized in that: The motion platform (1) has a cuboid structure.

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