4pus-3ups redundant drive parallel robot

Abstract

A 4PUS-3UPS redundant drive parallel robot belongs to the technical field of precision machining, and can guarantee that the parallel robot has the advantages of high rigidity, large bearing capacity, low inertia and no cumulative error, and overcome the problems of poor tilting ability of a moving platform and kinematic singularity in a working space. Four PUS branch chains and three UPS branch chains are connected between a fixed frame and the moving platform. The four PUS branch chains and the three UPS branch chains with independent linear modules are used to realize the redundant drive of the six-degree-of-freedom parallel mechanism, the PUS branch chains and the UPS branch chains drive simultaneously, the moving platform realizes large-angle tilting, and the singular shape position in the movement process is overcome. The inverse kinematics solution of the UPS branch chain in the application is easy to obtain, and kinematics analysis is easy to carry out. The rotating center of the Hooke joint in the UPS branch chain is on the extension line of the UPS connecting rod, so that the UPS connecting rod is only subjected to tension, and dynamics analysis is easy to carry out. The UPS branch chain has only one moving linear module, so that the inertia of the branch chain is small and there is no cumulative error.

Description

Technical Field

[0001] This invention belongs to the field of precision machining technology, specifically relating to a 4PUS-3UPS redundant drive parallel robot. Background Technology

[0002] Parallel robots can be defined as closed-loop mechanisms with at least two independent kinematic chains connecting a moving platform and a stationary platform, the moving platform having two or more degrees of freedom, and driven in parallel.

[0003] Parallel robots possess advantages such as high rigidity, large load-bearing capacity, low inertia, and no cumulative error, and are therefore widely used in the field of mechanical manufacturing. Existing parallel robot technology can fully leverage these advantages, but problems such as small workspace, poor tilting ability of the moving platform, and singularities in motion within the workspace still urgently need to be addressed.

[0004] A parallel robot based on redundant drive, proposed by Huang Hailin et al. from Harbin Institute of Technology (Shenzhen) (patent application number 201911210453.6), employs four follower branches and one central branch. Each follower branch has six degrees of freedom and one translational drive joint, while the central branch has six degrees of freedom and three mutually orthogonal translational drive joints. Its unique central branch structure effectively enables large-angle tilting of the moving platform and overcomes the singularity of motion within the workspace through redundant drive. However, because the central branch has three translational drive joints connected in series, it suffers from significant inertia and substantial cumulative error.

[0005] Based on this, the present invention proposes a 4PUS-3UPS redundant drive parallel robot, which aims to solve the problems of poor tilting ability and singularity in the workspace of parallel robots, while ensuring that the original advantages of parallel robots are not lost. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a 4PUS-3UPS redundant drive parallel robot. The aim is to overcome the problems of poor tilting ability of the moving platform and motion singularity within the workspace while ensuring that the parallel robot has the advantages of high rigidity, large load-bearing capacity, low inertia, and no cumulative error.

[0007] The technical solution adopted in this invention is:

[0008] A 4PUS-3UPS redundant drive parallel robot includes a fixed frame and a moving platform; the fixed frame and the moving platform are connected by four PUS branches and three UPS branches.

[0009] Compared with the prior art, the present invention has the following advantages:

[0010] 1. This invention achieves redundant drive of a six-degree-of-freedom parallel mechanism through four PUS branches and three UPS branches with independent linear modules. The simultaneous drive of the PUS and UPS branches enables the moving platform to tilt at large angles and overcomes singular shapes and positions during motion. The UPS branches in this invention are easy to derive inverse kinematics from, facilitating kinematic analysis. Furthermore, the Hooke's joint rotation center in the UPS branches is located on the extension line of the UPS link, ensuring the UPS link is only subjected to tension, thus facilitating dynamic analysis.

[0011] 2. This invention does not use a central branch; instead, it uses three UPS branches. The advantage is that each branch has only one moving linear module, resulting in low branch inertia and no cumulative error, while still maintaining the large tilting capability of the moving platform and the ability to overcome motion singularities in the workspace. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 ;

[0013] Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 ;

[0014] Figure 3 This is a schematic diagram of the PUS branched linear module structure of the present invention;

[0015] Figure 4 This is a schematic diagram of the UPS branch chain linear module structure of the present invention;

[0016] Figure 5 This is a schematic diagram of a large tilt state according to the present invention;

[0017] Figure 6 This is a schematic diagram of another large tilt state of the present invention;

[0018] The components are as follows: 10. Fixed frame; 11. Column; 12. Cover plate; 13. Base plate; 20. Moving platform; 30. PUS branch chain; 31. Sliding pair 1; 311. Drive motor 1; 312. Lead screw 1; 313. Guide rod 1; 314. Slider 1; 315. Adapter plate 1; 32. Hooke hinge 1; 33. PUS connecting rod; 34. Ball joint 1; 40. UPS branch chain; 41. Hooke hinge 2; 42. Sliding pair 2; 421. Drive motor 2; 422. Lead screw 2; 423. Guide rod 2; 424. Slider 2; 425. Adapter plate 2; 43. UPS connecting rod; 44. Ball joint 2. Detailed Implementation

[0019] To better understand the purpose, structure, and function of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0020] Reference Figures 1-6 As shown, a 4PUS-3UPS redundant drive parallel robot of the present invention includes a fixed frame 10 and a moving platform 20; the fixed frame 10 and the moving platform 20 are connected by four PUS branches 30 and three UPS branches 40. The four PUS branches 30 are evenly distributed at the four corners of the fixed frame 10, and the three UPS branches 40 are evenly distributed around the moving platform 20 and intersected between the four PUS branches 30. Specifically, the lower ends of the four PUS branches 30 are connected to the lower part of the moving platform 20, and the lower ends of the three UPS branches 40 are connected to the upper part of the moving platform 20, enabling the moving platform 20 to rotate smoothly.

[0021] The fixed frame 10 includes a cover plate 12, a base plate 13, and four columns 11 installed between the cover plate 12 and the base plate 13. The cover plate 12 is provided with three UPS branch chains 40 with Hooke hinge 2 41 installation positions.

[0022] like Figure 1 , Figure 2 As shown, each PUS branch chain 30 has the same structure, including a sliding joint 31, a Hooke hinge 32, a PUS link 33, and a ball joint 34. The upper end of the PUS link 33 is connected to the slider 314 of the sliding joint 31 through the Hooke hinge 32, and the lower end of the PUS link 33 is connected to the lower part of the moving platform 20 through the ball joint 34. The sliding joint 31 is mounted on the fixed frame 10.

[0023] Each PUS branch 30 has an independent linear module 31 for its moving joints, and each moving joint 31 has the same structure, such as... Figure 3 As shown, each component includes a drive motor 311, a lead screw 312, a guide rod 313, a slider 314, and an adapter plate 315. The lead screw 312 is rotatably mounted on the adapter plate 315. The drive motor 311 is driven by the lead screw 312. The guide rod 313 is arranged parallel to the lead screw 312 and is fixed to the adapter plate 315 along with the drive motor 311. The slider 314 passes through the guide rod 313 and is driven by the lead screw 312. The adapter plate 315 is fixed to the column 11 of the fixed frame 10.

[0024] like Figure 1 , Figure 2 As shown, each UPS branch chain 40 has the same structure, including Hooke hinge 2 41, sliding joint 2 42, UPS connecting rod 43 and ball joint 2 44; Hooke hinge 2 41 is fixedly connected to the upper end of the fixed frame 10, the upper end of sliding joint 2 42 is hinged to Hooke hinge 2 41, the upper end of UPS connecting rod 43 is fixedly connected to the slider 2 424 of sliding joint 2 42, the lower end of UPS connecting rod 43 is connected to the upper part of the moving platform 20 through ball joint 2 44, and the rotation center of Hooke hinge 2 41 is located on the extension line of UPS connecting rod 43.

[0025] Each UPS branch 40 has an independent linear module 42 for its moving auxiliary unit 2. Each moving auxiliary unit 2 42 has the same structure, such as... Figure 4 As shown, each component includes a second drive motor 421, a second lead screw 422, a second guide rod 423, a second slider 424, and a second adapter plate 425. The second lead screw 422 is rotatably mounted on the second adapter plate 425. The second drive motor 421 is driven by the second lead screw 422. The second guide rod 423 is arranged parallel to the second lead screw 422 and is fixed to the second adapter plate 425 along with the second drive motor 421. The second slider 424 passes through the second guide rod 423 and is driven by the second lead screw 422. The second adapter plate 425 is hinged to the cover plate 12 of the fixed frame 10.

[0026] In this invention, the linear modules of four prismatic joints 31 and three prismatic joints 42 provide seven input drives for the parallel robot, enabling the 4PUS-3UPS parallel mechanism with six degrees of freedom to achieve redundant drive, thereby overcoming the singular shape and position of the workspace and improving stiffness and load-bearing capacity. Furthermore, under the action of the four surrounding PUS branches and the three UPS branches at the top, a large-angle tilting of the moving platform is achieved. See [link to relevant documentation]. Figure 5 , Figure 6 .

[0027] In this invention, each branch has only one linear module, that is, each branch has only one drive joint, so that each branch has no cumulative error during movement and has low inertia, which allows for high-speed movement.

[0028] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A 4PUS-3UPS redundant drive parallel robot, comprising a fixed frame (10) and a moving platform (20); characterized in that: The fixed frame (10) and the moving platform (20) are connected by four PUS branches (30) and three UPS branches (40). The lower ends of the four PUS branches (30) are connected to the lower part of the moving platform (20), and the lower ends of the three UPS branches (40) are connected to the upper part of the moving platform (20), enabling the moving platform (20) to tilt. Each UPS branch (40) includes a second Hooke hinge (41), a second sliding joint (42), and a UPS connecting rod (43). The second ball joint (44) and the second ball joint (41); the second Hooke hinge (41) is fixedly connected to the upper end of the fixed frame (10), the upper end of the second movable joint (42) is hinged on the second Hooke hinge (41), the upper end of the UPS connecting rod (43) is fixedly connected to the second slider (424) of the second movable joint (42), the lower end of the UPS connecting rod (43) is connected to the upper part of the moving platform (20) through the second ball joint (44), and the rotation center of the second Hooke hinge (41) is located on the extension line of the UPS connecting rod (43).

2. The 4PUS-3UPS redundant drive parallel robot according to claim 1, characterized in that: The four PUS branches (30) are evenly distributed at the four corners of the fixed frame (10), and the three UPS branches (40) are evenly distributed around the moving platform (20) and intersected between the four PUS branches (30).

3. The 4PUS-3UPS redundant drive parallel robot according to claim 1, characterized in that: Each of the PUS branches (30) includes a sliding joint (31), a Hooke hinge (32), a PUS link (33), and a ball joint (34); the upper end of the PUS link (33) is connected to the slider (314) of the sliding joint (31) through the Hooke hinge (32), and the lower end of the PUS link (33) is connected to the lower part of the moving platform (20) through the ball joint (34). The sliding joint (31) is mounted on the fixed frame (10).

4. A 4PUS-3UPS redundant drive parallel robot according to claim 3, characterized in that: Each of the PUS branch chains (30) has a moving joint (31) that is an independent linear module. Each moving joint (31) includes a drive motor (311), a lead screw (312), a guide rod (313), a slider (314), and an adapter plate (315). The lead screw (312) is rotatably mounted on the adapter plate (315). The drive motor (311) is driven to connect with the lead screw (312). The guide rod (313) is parallel to the lead screw (312). The guide rod (313) and the drive motor (311) are fixed on the adapter plate (315). The slider (314) passes through the guide rod (313) and is driven to connect with the lead screw (312). The adapter plate (315) is fixed on the column (11) of the fixed frame (10).

5. A 4PUS-3UPS redundant drive parallel robot according to claim 1, characterized in that: Each UPS branch (40) has a movable sub-module (42) that is an independent linear module. Each movable sub-module (42) includes a drive motor (421), a lead screw (422), a guide rod (423), a slider (424), and an adapter plate (425). The lead screw (422) is rotatably mounted on the adapter plate (425). The drive motor (421) is driven to the lead screw (422). The guide rod (423) is parallel to the lead screw (422). The guide rod (423) and the drive motor (421) are fixed on the adapter plate (425). The slider (424) passes through the guide rod (423) and is driven to the lead screw (422). The adapter plate (425) is hinged to the cover plate (12) of the fixed frame (10).

6. A 4PUS-3UPS redundant drive parallel robot according to claim 1, characterized in that: The fixed frame (10) includes a cover plate (12), a base plate (13) and four columns (11) installed between the cover plate (12) and the base plate (13). The cover plate (12) is provided with the installation positions of the three UPS branches (40) Hooke hinges (41).

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