Motion redundancy six-degree-of-freedom 6-PSPS parallel mechanism with symmetrical structure

Abstract

The utility model relates to the technical field of robots, in particular to a motion redundancy six-degree-of-freedom 6-PSPS parallel mechanism with a symmetrical structure, which comprises a static platform, a movable platform with an electric spindle and branch chains connected between the static platform and the movable platform, and the branch chains comprise a first branch chain, a second branch chain, a third branch chain, a fourth branch chain, a fifth branch chain and a sixth branch chain. The six branch chains are the same in structure and are evenly distributed in the circumferential direction of the movable platform at 60-degree intervals, one end of each branch chain is connected with the movable platform, the other end of each branch chain is connected with the fixed platform, and the parallel mechanism has the advantages of being high in speed, precision and rigidity, large in rotation angle, high in flexibility and the like and can be used for machining and polishing large aviation structural parts.

Description

Technical Field

[0001] The utility model relates to the technical field of robots, and specifically to a motion-redundant six-degree-of-freedom 6-PSPS parallel mechanism with a symmetric structure. Background Art

[0002] Compared with serial mechanisms, parallel mechanisms have significant advantages in terms of stiffness, accuracy, speed, and dynamic performance. Therefore, they have been widely used in industrial production, such as in fields like material handling and palletizing, motion simulation, surgical medicine, and component processing. The six-degree-of-freedom Stewart platform is a typical parallel mechanism. From the perspective of mechanism theory, the six-degree-of-freedom Stewart platform is a 6-SPS parallel mechanism. Through the telescopic motion of six branches, the load platform can achieve six-degree-of-freedom motion within the workspace, including three translational degrees of freedom and three rotational degrees of freedom. It has advantages such as high stiffness, high accuracy, strong load-bearing capacity, and good dynamic characteristics. Therefore, it has been widely applied to parallel machine tools, precision positioning platforms, and vibration isolation platforms in recent years. Parallel machine tools are an important type of high-end equipment, which are used for processing complex components and are also the high-end equipment support for China's transformation from a "manufacturing giant" to a "manufacturing powerhouse".

[0003] Although the 6-SPS parallel mechanism has been applied to a certain extent in industrial production, there are still some deficiencies that limit its further promotion in the market. For example, the mechanism does not have redundant degrees of freedom of motion, the tool workspace and rotation angle are relatively small, there are many singular configurations within the workspace, the flexibility is insufficient, and it is difficult to achieve high-speed and high-precision machining and grinding of some complex components. Therefore, based on the 6-SPS parallel mechanism, it is necessary to develop and design a motion-redundant six-degree-of-freedom parallel mechanism. Content of the Utility Model

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present utility model is to provide a motion-redundant six-degree-of-freedom 6-PSPS parallel mechanism with a symmetric structure.

[0005] To achieve the above purpose, the present utility model provides the following technical solution: A motion-redundant six-degree-of-freedom 6-PSPS parallel mechanism with a symmetric structure, comprising a static platform, a moving platform with an electric spindle, and branches connecting the static platform and the moving platform. The branches include a first branch, a second branch, a third branch, a fourth branch, a fifth branch, and a sixth branch. The six branches have the same structure and are evenly distributed at intervals of 60° along the circumferential direction of the moving platform. One end of each branch is connected to the moving platform, and the other end is connected to a fixed platform.

[0006] In some of these embodiments, the six branch chains each include a first prismatic pair, a first spherical pair, a second prismatic pair, and a second spherical pair. The first prismatic pair is provided on the fixed platform, the first spherical pair is provided on the first prismatic pair and is connected to the second prismatic pair, the second spherical pair is provided on the second prismatic pair and is connected to the fixed platform.

[0007] In some of these embodiments, the first prismatic pair includes a slider, a guide rail, and a lead screw. The guide rail is mounted on the fixed platform, the slider is slidably mounted on the guide rail, and the lead screw is mounted on the fixed platform and is matched with the slider.

[0008] In some of these embodiments, the second prismatic pair is a hydraulic cylinder. One end of the hydraulic cylinder is rotatably connected to the slider through the first spherical pair, and the other end of the hydraulic cylinder is provided with the second spherical pair.

[0009] In some of these embodiments, the first prismatic pairs and the second prismatic pairs of the six branch chains are coplanar and perpendicular to the revolute pair. The connection points of each branch chain to the static platform and the moving platform respectively form equilateral hexagons.

[0010] Compared with the prior art, the beneficial effects of the present utility model are as follows: The parallel mechanism proposed in this application has the characteristic of motion redundancy. The output motion of the moving platform is still six degrees of freedom, including three rotational degrees of freedom and three translational degrees of freedom. It has the advantages of high speed, high precision, high stiffness, large rotation angle, high flexibility, etc., and can be used for the processing and grinding of large aviation structural parts.

[0011] The details of one or more embodiments of this application are set forth in the following drawings and description, so that the other features, purposes, and advantages of this application are more concise and understandable. The present application is described in detail and understood through the embodiments of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic structural diagram of the present utility model;

[0013] Figure 2 is a schematic structural diagram of the first branch chain of the present utility model;

[0014] Figure 3 is a schematic structural diagram of the moving platform of the present utility model.

[0015] In the figure: 1, static platform; 2, first branch chain; 3, second branch chain; 4, third branch chain; 5, fourth branch chain; 6, fifth branch chain; 7, sixth branch chain; 8, moving platform; 9, electric spindle. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] Please refer to Figures 1-3 , the present invention provides a technical solution: a kinematically redundant six-degree-of-freedom 6-PSPS parallel mechanism with symmetric structure, including a static platform, a moving platform with an electric spindle, and a chain connected between the static platform and the moving platform. The chain includes a first chain, a second chain, a third chain, a fourth chain, a fifth chain, and a sixth chain. The six chains have the same structure and are evenly distributed at intervals of 60° along the circumferential direction of the moving platform. One end of each chain is connected to the moving platform, and the other end is connected to a fixed platform.

[0018] The six chains all include a first moving pair, a first spherical pair, a second moving pair, and a second spherical pair. The first moving pair is arranged on the fixed platform, the first spherical pair is arranged on the first moving pair and is connected to the second moving pair, and the second spherical pair is arranged on the second moving pair and is connected to the fixed platform.

[0019] The driving mode of the moving pair can be selected as ball screw or hydraulic drive, and the driving mode of the rotating pair can be selected as servo motor drive.

[0020] The first moving pair includes a slider, a guide rail, and a screw rod. The guide rail is installed on the fixed platform, the slider is slidably installed on the guide rail, the screw rod is installed on the fixed platform, and a threaded hole matching the screw rod is provided on the slider. The rotation of the screw rod drives the slider to move on the guide rail.

[0021] A servo motor is arranged at the end of the screw rod. The rotation of the screw rod is driven by the servo motor, and the slider is linked to move on the guide rail, so as to realize the movement of the slider on the fixed platform.

[0022] The second moving pair is a hydraulic cylinder. One end of the hydraulic cylinder is rotatably connected to the slider through a first spherical pair, and a second spherical pair is arranged at the other end of the hydraulic cylinder. The hydraulic cylinder includes a telescopic rod inner rod and a telescopic rod outer rod that cooperate with each other.

[0023] A spherical outer shell is arranged on the slider and forms a first spherical pair with the ball head on the telescopic rod outer rod;

[0024] The telescopic rod inner rod is connected to the moving platform through a second spherical pair;

[0025] The first and second moving pairs of the six branch chains are coplanar and perpendicular to the rotating pair, and the connection points of each branch chain to the static platform and the moving platform respectively form an equilateral hexagon.

[0026] Through this technical solution, from the beginning, by controlling the movement of 12 driving pairs, the six branches of the mechanism can generate redundant degrees of freedom of motion, reduce input singular configurations, increase the rotation angle of the moving platform, and improve the flexibility of the mechanism. For a motion-redundant six-degree-of-freedom 6-PSPS parallel mechanism used for processing large-scale aviation structural parts, the parallel mechanism should have the advantages of high stiffness accuracy, good flexibility, fast processing speed, large working space, and few singular configurations.

[0027] The above embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

[0028] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A symmetrical, redundant, six-DOF 6-PSPS parallel mechanism, characterized in that: It includes a static platform, a dynamic platform with an electric spindle, and a branch chain connected between the static platform and the dynamic platform. The branch chain includes a first branch chain, a second branch chain, a third branch chain, a fourth branch chain, a fifth branch chain and a sixth branch chain. The six branch chains have the same structure and are evenly distributed at 60° intervals along the circumferential direction of the dynamic platform. One end of each branch chain is connected to the dynamic platform, and the other end is connected to a certain platform. The six branch chains each include a first moving pair, a first ball pair, a second moving pair and a second ball pair. The first moving pair is arranged on the fixed platform, the first ball pair is arranged on the first moving pair and is connected to the second moving pair, and the second ball pair is arranged on the second moving pair and is connected to the fixed platform.

2. A structurally symmetrical motion redundant six-DOF 6-PSPS parallel mechanism according to claim 1, characterized in that: The first moving pair comprises a slider, a guide rail and a screw, wherein the guide rail is mounted on a fixed platform, the slider is slidably mounted on the guide rail, the screw is mounted on the fixed platform, and the screw matches the slider.

3. A structurally symmetrical motion redundant six-DOF 6-PSPS parallel mechanism according to claim 1, characterized in that: The second moving pair is a hydraulic cylinder, one end of which is rotatably connected to the slider via a first ball pair, and the other end of the hydraulic cylinder is provided with a second ball pair.

4. The structurally symmetrical kinematically redundant six-DOF 6-PSPS parallel mechanism according to claim 1, characterized in that: The first moving pairs and the second moving pairs of the six branches are coplanar and perpendicular to the rotating pairs, and the connection points of each branch chain with the static platform and the dynamic platform respectively form an equilateral hexagon.

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