A four-branched chain redundant drive 2R1T parallel mechanism

Abstract

The application discloses a four-branch-chain redundant driving 2R1T parallel mechanism and belongs to the technical field of low-freedom parallel mechanisms. The four-branch-chain redundant driving 2R1T parallel mechanism comprises a static platform, a dynamic platform, four driving branch chains and a central constraint branch chain arranged between the static platform and the dynamic platform, the four driving branch chains are evenly distributed on the periphery of the central constraint branch chain, and the static platform, the dynamic platform, the central constraint branch chain and the four driving branch chains jointly form any one of 2PUP-R-2PUP configuration, 2PRU-R-2PRU configuration and 4-PPRR-P configuration. Compared with common three-branch-chain driving, the four-branch-chain redundant driving in the application is a new antagonistic driving mode, has a larger supporting area and a more uniform force distribution due to the additional branch chain, and can bear a larger load.

Description

Technical Field

[0001] This invention relates to the field of parallel mechanisms with few degrees of freedom, and in particular to a 2R1T parallel mechanism with redundant four-branch drive. Background Technology

[0002] In mechanics, parallel robots with few degrees of freedom (DOFs) have always been a research focus, with these mechanisms having between 2 and 5 DDFs. Compared to 6-DOF parallel mechanisms, DDF parallel mechanisms offer advantages in terms of the number of drives, components, control complexity, manufacturing difficulty, assembly difficulty, and manufacturing cost. Compared to 6-DOF parallel mechanisms, DDF parallel mechanisms exhibit more complex motion characteristics because the movement and rotation of the moving platform are restricted, resulting in many unique properties. In the industrial field, the parallel section of a 5-DOF parallel machine tool is the most widely used form of the 2R1T parallel configuration; in the field of rehabilitation robots, ankle rehabilitation robots need to meet the 3-DOF motion capability of 2R1T; in the medical field, the 2R1T configuration can be used as a remote motion center mechanism for minimally invasive surgery and a novel dexterous endoscopic parallel manipulator for minimally invasive surgery; in addition, parallel mechanisms with 2R1T motion capability can also be applied to the leg design of mobile robots and the wrist and ankle joint design of exoskeleton robots.

[0003] Parallel mechanisms with few degrees of freedom have two main applications: one is standalone application, but this is relatively rare, such as the Tricept assembly robot; the other is to be used in series with other mechanisms to form a hybrid mechanism, which is more common, such as the Exechon hybrid robot.

[0004] Common three-chain drives have a small support area and uneven force distribution, cannot withstand larger loads, have average stability and stiffness, uneven load distribution in various directions, make the dynamic behavior of the mechanism difficult to predict, have complex mathematical models, and the corresponding control algorithms have high complexity.

[0005] Therefore, how to provide a 2R1T parallel mechanism with four redundant drives that can overcome the above problems is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To achieve the above objectives, the present invention provides a 2R1T parallel mechanism with four-branch redundant drive, including a static platform, a moving platform, four drive branches, and a central constraint branch disposed between the static platform and the moving platform. The four drive branches are evenly distributed around the central constraint branch. The static platform, the moving platform, the central constraint branch, and the four drive branches together constitute any one of the following configurations: 2PUP-R-2PUP, 2PRU-R-2PRU, and 4-PPRR-P.

[0007] Preferably, the static platform, the dynamic platform, the central constraint branch, and the four driving branches together constitute a 2PUP-R-2PUP configuration, wherein the driving branches are PUP branches and the central constraint branches are R constraint branches.

[0008] Preferably, four telescopic components are fixed on the static platform, and the telescopic directions of the telescopic ends of the four telescopic components are parallel to each other; one end of each of the four Hooke hinges is fixedly connected to the telescopic end of the four telescopic components, and the other end of each of the four Hooke hinges is fixedly connected to the four sliders; two connecting rods are rotatably connected and have a rotation axis, which is perpendicular to the length direction of the connecting rods; two sliders are slidably mounted on each connecting rod; the rotation axis is located within the area defined by the four sliders; and the four sliders together constitute the moving platform.

[0009] Preferably, the static platform, the dynamic platform, the central constraint branch, and the four driving branches together constitute a 2PRU-R-2PRU configuration, wherein the driving branches are PRU branches and the central constraint branches are R constraint branches.

[0010] Preferably, four telescopic members 2 are fixed on the static platform, and the telescopic directions of the telescopic ends of the four telescopic members 2 are parallel to each other; one end of each of the four hinge members is hinged to the telescopic end of the four telescopic members 2, and the other end of each of the four hinge members is connected to one end of the four Hooke hinges 2. The other end of each of the four Hooke hinges 2 is connected to a rotating base, and a turntable is rotatably mounted on the rotating base. The turntable has a rotation axis 2 relative to the rotating base, and the rotation axis 2 is located within the area jointly defined by the four Hooke hinges 2. The turntable is the moving platform.

[0011] Preferably, the static platform, the dynamic platform, the central constraint branch, and the four driving branches together constitute a 4-PPRR-P configuration, wherein the driving branches are PPRR branches and the central constraint branches are P constraint branches.

[0012] Preferably, four connecting rods 2 are slidably mounted on the static platform. The length directions of the four connecting rods 2 are parallel to each other, and the direction of movement of the connecting rods 2 relative to the static platform is the same as the length direction of the connecting rods 2. A slider 2 is fixed at one end of each connecting rod 2. Four connecting rods 3 are slidably inserted into the four sliders 2. The length direction of the connecting rods 3 is perpendicular to the length direction of the connecting rods 2, and the direction of movement of the connecting rods 3 relative to the sliders 2 is the same as the length direction of the connecting rods 3. A connector is rotatably mounted at one end of each connecting rod 3. Two moving blocks are arranged within the area defined by the four connecting rods 2. Each moving block is rotatably connected to two connectors simultaneously. Each moving block is provided with a hole and a rod. The rod on one moving block is slidably inserted into the hole on the other moving block. The two moving blocks together constitute the moving platform.

[0013] The advantages and positive effects of the four-branch redundant drive 2R1T parallel mechanism described in this invention are: 1. Compared with the common three-branch drive, the four-branch redundant drive in this invention is a new antagonistic drive method. Due to the addition of one branch, it has a larger support area and a more uniform force distribution, and can withstand a larger load.

[0014] 2. Due to the increased number of fulcrums, this mechanism offers better stability and rigidity, making it suitable for mechanical systems requiring high-precision positioning and operation.

[0015] 3. The mechanism has a symmetrical configuration, with the load evenly distributed in all directions, reducing additional wear and damage caused by off-center loading and imbalance. Due to its uniform geometric distribution, the dynamic behavior of the mechanism is more predictable and consistent, simplifying the mathematical model. This not only reduces the complexity of the control algorithm but also improves its efficiency and reliability, and enhances the coordination of the overall system response. Attached Figure Description

[0016] Figure 1 This is an isometric view of the present invention in the 2PUP-R-2PUP configuration; Figure 2 This is an isometric view of the present invention in the 2PRU-R-2PRU configuration; Figure 3 This is an isometric view of the present invention in the 4-PPRR-P configuration.

[0017] Figure Labels 1. Static platform; 2. Telescopic component one; 3. Hooke hinge one; 4. Slider one; 5. Link one; 6. Telescopic component two; 7. Hinge; 8. Hooke hinge two; 9. Rotating base; 10. Turntable; 11. Link two; 12. Slider two; 13. Link three; 14. Connector; 15. Moving block; 16. Insert rod. Detailed Implementation

[0018] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing the 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 the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0020] See appendix Figure 1-3 This is a schematic diagram of the overall and partial structure of one embodiment of the present invention. Specifically, the present invention discloses a 2R1T parallel mechanism with four redundant drives, including a static platform 1, a moving platform, four drive branches, and a central constraint branch located between the static platform 1 and the moving platform. The four drive branches are evenly distributed around the central constraint branch circumferentially. Each of the four drive branches is equipped with an active drive pair, and the number of drive inputs is greater than the overall degrees of freedom of the mechanism, forming a redundant drive layout. The mechanism outputs a 2R1T three-degree-of-freedom motion with two rotations and one translation.

[0021] The static platform 1 and the moving platform are connected by four driving branches and a central constraint branch to form an integrated mechanism. The naming rule for the mechanism configuration is "driving branch - central constraint branch". The mechanism can be any one of the following configurations: 2PUP-R-2PUP, 2PRU-R-2PRU, or 4-PPRR-P. Where: P represents a prismatic joint, R represents a revolute joint, and U represents a Hooke's joint.

[0022] When the static platform 1, the moving platform, the central constraint branch, and the four driving branches together form a 2PUP-R-2PUP configuration, the driving branches are PUP branches and the central constraint branches are R constraint branches.

[0023] Specifically, four telescopic components 2 are fixed on the static platform 1. The telescopic ends of the four telescopic components 2 are parallel to each other, and their telescopic ends can move synchronously or independently. One end of each of the four Hooke hinges 3 is fixedly connected to the telescopic end of the four telescopic components 2, and the other end of each of the four Hooke hinges 3 is fixedly connected to four sliders 4. Two connecting rods 5 are rotatably connected and have a rotation axis 1, which is perpendicular to the length direction of the connecting rods 5. Two sliders 4 are slidably mounted on each connecting rod 5. The rotation axis 1 is located within the area defined by the four sliders 4, and the four sliders 4 together constitute the moving platform. When the four telescopic components 2 move synchronously, the Hooke hinges 3 themselves do not rotate, and the four Hooke hinges 3 move synchronously with the four telescopic components 2, thus realizing the translation of the moving platform. When the telescopic ends of the four telescopic components 2 move asynchronously and at different speeds, the Hooke hinges themselves will deflect, and the two connecting rods 5 will also rotate relative to each other, thus realizing the overturning motion of the moving platform.

[0024] When the static platform 1, the moving platform, the central constraint branch, and the four driving branches together form a 2PRU-R-2PRU configuration, the driving branches are PRU branches, and the central constraint branches are R constraint branches. This configuration is based on the same principle as the aforementioned 2PUP-R-2PUP configuration.

[0025] Specifically, four telescopic components 6 are fixed on the static platform 1, and the telescopic directions of the four telescopic components 6 are parallel to each other. One end of each of the four hinge components 7 is hinged to the telescopic end of the four telescopic components 6, and the other end of each of the four hinge components 7 is connected to one end of each of the four Hooke hinges 8. The other ends of the four Hooke hinges 8 are all connected to a rotating base 9. A turntable 10 is rotatably mounted on the rotating base 9. The turntable 10 has a rotation axis line 2 relative to the rotating base 9. The rotation axis line 2 is located within the area jointly defined by the four Hooke hinges 8. The turntable 10 is the moving platform.

[0026] When the static platform 1, the moving platform, the central constraint branch, and the four driving branches together form a 4-PPRR-P configuration, the driving branches are PPRR branches, and the central constraint branches are P constraint branches.

[0027] Specifically, four connecting rods 11 are slidably mounted on the static platform 1. These four connecting rods 11 can connect to external telescopic devices, which can drive the four connecting rods 11 to move synchronously or independently. The lengths of the four connecting rods 11 are parallel to each other, and the direction of movement of each connecting rod relative to the static platform 1 is the same as its length. A slider 12 is fixed to one end of each connecting rod 11. Four connecting rods 13 are slidably inserted onto the four sliders 12. The length of each connecting rod 13 is perpendicular to the length of each connecting rod 11, and the direction of movement of each connecting rod relative to the sliders 12 is the same as its length. A connector 14 is rotatably mounted to one end of each connecting rod 13. Two movable blocks 15 are arranged in the area defined by the four connecting rods 11. Each movable block 15 is rotatably connected to two connecting parts 14. Each movable block 15 is provided with a socket and a rod 16. The rod 16 on one movable block 15 is slidably inserted into the socket on the other movable block 15. The two movable blocks 15 together constitute a moving platform.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A 2R1T parallel mechanism with four-branch redundant drive, characterized in that, It includes a static platform, a moving platform, four drive branches, and a central constraint branch located between the static platform and the moving platform. The four drive branches are evenly distributed around the central constraint branch. The static platform, the moving platform, the central constraint branch, and the four drive branches together constitute any one of the following configurations: 2PUP-R-2PUP, 2PRU-R-2PRU, and 4-PPRR-P.

2. The 2R1T parallel mechanism with four-branch redundant drive according to claim 1, characterized in that, The static platform, the dynamic platform, the central constraint branch, and the four driving branches together constitute a 2PUP-R-2PUP configuration, wherein the driving branches are PUP branches and the central constraint branches are R constraint branches.

3. The 2R1T parallel mechanism with four-branch redundant drive according to claim 2, characterized in that, Four telescopic components are fixed on the static platform, and the telescopic ends of the four telescopic components are parallel to each other. One end of each of the four Hooke hinges is fixedly connected to the telescopic end of the four telescopic components, and the other end of each of the four Hooke hinges is fixedly connected to the four sliders. Two connecting rods are rotatably connected and have a rotation axis line, which is perpendicular to the length direction of the connecting rods. Two sliders are slidably mounted on each connecting rod. The rotation axis line is located within the area defined by the four sliders. The four sliders together constitute the moving platform.

4. The 2R1T parallel mechanism with four-branch redundant drive according to claim 1, characterized in that, The static platform, the dynamic platform, the central constraint branch, and the four driving branches together constitute a 2PRU-R-2PRU configuration, where the driving branches are PRU branches and the central constraint branches are R constraint branches.

5. The 2R1T parallel mechanism with four-branch redundant drive according to claim 4, characterized in that, Four telescopic components are fixed on the static platform, and the telescopic ends of the four telescopic components are parallel to each other. One end of each of the four hinges is hinged to the telescopic end of the four telescopic components, and the other end of each of the four hinges is connected to one end of the four Hooke hinges. The other end of each of the four Hooke hinges is connected to a rotating base. A turntable is rotatably mounted on the rotating base. The turntable has a rotation axis line II relative to the rotating base. The rotation axis line II is located within the area jointly defined by the four Hooke hinges. The turntable is the moving platform.

6. The 2R1T parallel mechanism with four-branch redundant drive according to claim 1, characterized in that, The static platform, the dynamic platform, the central constraint branch, and the four driving branches together constitute a 4-PPRR-P configuration, wherein the driving branches are PPRR branches and the central constraint branches are P constraint branches.

7. A four-branch redundant-drive 2R1T parallel mechanism according to claim 6, characterized in that, Four connecting rods 2 are slidably mounted on the static platform. The length directions of the four connecting rods 2 are parallel to each other, and the direction of movement of each connecting rod 2 relative to the static platform is the same as the length direction of the connecting rod 2. A slider 2 is fixed at one end of each connecting rod 2. Four connecting rods 3 are slidably inserted into the four sliders 2. The length direction of each connecting rod 3 is perpendicular to the length direction of the connecting rod 2, and the direction of movement of each connecting rod 3 relative to the slider 2 is the same as the length direction of the connecting rod 3. A connector is rotatably mounted at one end of each connecting rod 3. Two moving blocks are arranged within the area defined by the four connecting rods 2. Each moving block is rotatably connected to both connectors simultaneously. Each moving block is provided with a hole and a rod. The rod on one moving block is slidably inserted into the hole on the other moving block. The two moving blocks together constitute the moving platform.

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