A high-speed five-DOF parallel robot based on a linkage slide and a defined axis of rotation.

Abstract

This invention relates to a high-speed five-DOF parallel robot based on a linkage mechanism with a defined axis of rotation, belonging to the field of robot technology. It includes a frame, a moving platform, an end effector, five drive motors, and first, second, and third branches connected in parallel between the frame and the moving platform, wherein the first and second branches have identical structures. This invention employs a linkage mechanism with a three-branch parallel configuration to achieve five-DOF motion. It features a compact structure, high load capacity, and a large workspace. Furthermore, the mechanism has a defined axis of rotation and analytical forward kinematics, allowing for better integration with vision positioning systems. It shows promising application prospects in assembly, sorting, and machining.

Description

Technical Field

[0001] This invention relates to a high-speed five-degree-of-freedom parallel robot based on a linkage slide and having a defined axis of rotation, belonging to the field of robot technology. Technical Background

[0002] With increasing automation in domestic industrial production, the market demand for robots with higher rigidity and stability is becoming more urgent. Currently, common robot mechanisms are divided into serial and parallel types. Serial mechanisms are simple to control and have a large workspace, but their rigidity is insufficient, and errors accumulate. Parallel mechanisms have high rigidity, do not accumulate errors, and offer high precision and good dynamic performance. In sorting and assembly, the end effector of a five-degree-of-freedom robot has rotational freedom in two directions, enabling it to perform tasks that four-degree-of-freedom robots cannot, such as side placement, oblique insertion, and inclined screw locking. In the mechanical manufacturing field, the structural design and processing technology of parts are becoming increasingly complex. Parts used in automobiles, aerospace, and shipbuilding often have complex curved surfaces, requiring at least a five-degree-of-freedom robot with high load-bearing capacity to meet the processing requirements of curved surfaces such as machining, inspection, welding, and grinding. Therefore, a five-degree-of-freedom parallel robot with high load capacity, high precision, few branches, a large workspace, and the ability to mount different actuators at its end effector is urgently needed.

[0003] Chinese patent (CN 108858142 A) proposes a five-degree-of-freedom parallel robot that can be used to process complex curved surfaces such as eddies, and perform tasks such as welding, surface inspection, gluing, and laser processing. However, its mechanism has many links, does not employ a sliding table mechanism, has weak load-bearing capacity, and has a chain connecting it to the center of the moving platform, which compresses the installation space of the end effector; Chinese patent (CN 115741639) A) A five-DOF parallel robot for grinding ship bulkheads is proposed. Equipped with a grinding head, it can complete grinding tasks on free-curved surfaces such as ship bulkheads. However, its configuration has five branches from the frame to the moving platform, with many links that are prone to interference. The workspace is limited, and the mechanism does not have a definite axis of rotation, so there is no analytical positive solution. Chinese patent (CN115741638A) proposes a six-branch five-DOF parallel machining robot. Its unconstrained branches are driven by motors to achieve changes in the pose of the output assembly. The whole machine has high rigidity and good flexibility. However, it is essentially a six-branch parallel mechanism with the motors mounted on the branches, resulting in a complex kinematic model and large inertia. Chinese patent (CN 115771135A) proposes a parallel machining robot with a large workspace and few branches. It has high rigidity and a large workspace. However, its pose adjustment drive is mounted on a slide, and it moves with the movement of the drive slide, resulting in large inertia.

[0004] Existing five-degree-of-freedom parallel robots have the following problems:

[0005] (1) The multi-branch configuration has many restrictions on the interference of rods and joint movement, and the workspace is limited; (2) The drive components are arranged on the branches and move with the end of the mechanism. The mechanism has large inertia and is not suitable for high-speed motion scenarios; (3) The mechanism does not have a defined axis of rotation, the motion model is complex, lacks analytical forward solution or has high solution difficulty, and is not suitable for use with a vision positioning system. The level of intelligence is low; (4) There is a lack of a scheme in which a single branch contains two drive slides fixed on the frame; (5) It cannot simultaneously satisfy the requirements of few branches, low inertia, large workspace and relatively simple analytical forward solution, which will result in obvious shortcomings in practical applications.

[0006] To overcome the shortcomings of the aforementioned robot designs, this invention proposes a high-speed five-DOF parallel robot based on a linkage mechanism with a defined axis of rotation. By employing a novel linkage mechanism, five-DOF motion is achieved using only a three-branch parallel configuration. A key advantage of this robot compared to other five-DOF parallel robots with sliding mechanisms is that the linkage mechanism effectively reduces the number of branches through dual-slide linkage, minimizing joint constraints and link interference, resulting in a larger end-effector workspace. All drive components are fixed to the frame, resulting in lightweight branches and the end-effector, low inertia, and superior motion performance. Furthermore, the defined axis of rotation for both end-effector postures is crucial for mechanism calibration and trajectory planning, providing a relatively simple analytical forward kinematic solution. This allows for better integration with visual positioning systems and enables fully closed-loop feedforward control, leading to improved positioning accuracy and work efficiency. The proposed solution simultaneously satisfies the advantages of fewer branches, lower inertia, larger workspace, defined axis of rotation, and a relatively simple analytical forward kinematic solution, showing promising application prospects in complex component processing, assembly, and sorting. Summary of the Invention

[0007] To address the aforementioned issues, this invention provides a high-speed five-degree-of-freedom parallel robot based on a linkage slide and a defined axis of rotation. It employs a three-branch parallel mechanism to achieve five-degree-of-freedom motion. The mechanism has analytical forward solutions, a compact structure, high load capacity, and low manufacturing cost. It also possesses high rigidity and a large workspace. The moving platform can connect to various end effectors, including vacuum chucks, laser heads, spindle heads, and grinding heads. It can meet the needs of sorting and assembly scenarios, and can achieve composite processing while ensuring the machining accuracy of complex curved surfaces of workpieces.

[0008] The technical solution adopted to achieve the purpose of this invention is a high-speed five-degree-of-freedom parallel robot based on a linkage slide and a defined axis of rotation, belonging to the field of robot technology. It includes a frame, a moving platform, an end effector, five drive motors, and first, second, and third branches installed in parallel between the frame and the moving platform. The key feature is that one end of each of the first, second, and third branches is connected at equal intervals to a circle centered on the center of the upper surface of the frame, and the other end is connected at equal intervals to a circle centered on the center of the upper surface of the moving platform. The first branch has the same structure as the second branch. The first branch, from the frame to the moving platform, sequentially connects a linkage slide rod assembly 1, a long swing rod 1, a U-shaped fork 1, and a connecting short shaft 1. The linkage slide rod assembly 1 is fixed to the frame. The long swing rod 1 and the intermediate rod of the linkage slide rod assembly 1 are connected by a revolute joint 6. The U-shaped fork 1 and the long swing rod 1 are connected by a revolute joint 7. The connecting short shaft 1 and the U-shaped fork 1 are connected by a revolute joint 8. The connecting short shaft 1 and the moving platform are connected by a revolute joint 9. The axis of the revolute joint 6 is parallel to the upper part of the linkage slide rod assembly 1. In the plane, the axis of revolute joint seven is perpendicular to and intersects with the axis of revolute joint six; the axis of revolute joint eight is perpendicular to and intersects with the axis of revolute joint seven; the axis of revolute joint nine is perpendicular to and intersects with the axis of revolute joint eight; the axes of revolute joint seven, revolute joint eight, and revolute joint nine intersect; the third branch III is sequentially connected from the frame to the moving platform with a single-drive slide group and a four-way universal joint parallelogram mechanism. The single-drive slide group is fixed to the frame, and the bearing seat of the four-way universal joint parallelogram mechanism is fixed to the slider of the single-drive slide group. The bearing of the four-way universal joint parallelogram mechanism... Seat 2 is connected to the moving platform via rotating joint 18; motor 1 and motor 2 are installed on the linkage slide rod group 1 to jointly drive the movement and rotation of the middle rod of linkage slide rod group 1; motor 3 and motor 4 are installed on the linkage slide rod group 2 to jointly drive the movement and rotation of the driving short rod 3 of linkage slide rod group 2; motor 5 is installed on the single drive slide group to drive the movement of bearing seat 1 of the four universal joint parallelogram mechanism; the end effector is fixed to the moving platform and, according to the working requirements, is a suction cup, assembly gripper, dispensing head, welding head, or spindle head.

[0009] The high-speed five-degree-of-freedom parallel robot based on a linkage slide and a defined axis of rotation is characterized in that the four-universal-hinged parallelogram mechanism of the third branch of the robot is replaced with a four-ball-hinged parallelogram mechanism.

[0010] The beneficial effects provided by this invention are as follows: Compared with the existing technical solutions, the robot of this invention has a definite axis of rotation, which is beneficial for mechanism calibration and kinematic solution. It has analytical forward solutions and can not only be better matched with the vision positioning system, but also perform full closed-loop feedforward control. The robot has better positioning accuracy and work efficiency. The mechanism cleverly adopts a linkage slide linkage mechanism, which realizes three-dimensional movement and two-dimensional rotation with only three branches. The drive motor, reducer and other components are arranged on the frame. The branches and end effectors are lightweight, the mechanism has low inertia and excellent motion performance. At the same time, there is less interference between the links, and it has the advantages of large working space, high precision and high speed. The moving platform can connect to a variety of end effectors, including vacuum suction cups, laser heads, spindle heads and grinding heads, which can meet the needs of sorting and assembly scenarios and can realize composite processing and ensure the processing accuracy of complex curved surfaces of workpieces. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the overall structure of a high-speed five-degree-of-freedom parallel robot based on a linkage slide and a defined axis of rotation, as described in Example 1 of the present invention.

[0012] Among them, 1-frame, 2-moving platform, 3-end effector, a-motor one, b-motor two, c-motor three, d-motor four, e-motor five, H1-linkage slide rod group one, H2-linkage slide rod group two, H3-single drive slide group, L15-drive short rod three, Ⅰ-first branch, Ⅱ-second branch, Ⅲ-third branch, P-four universal joint parallelogram mechanism.

[0013] Figure 2 This is a schematic diagram of the first and second branch structures of a high-speed five-degree-of-freedom parallel robot based on a linkage slide and a defined axis of rotation, as described in Example 1 of the present invention.

[0014] Among them, G1-Slide Rail 1, G2-Slide Rail 2, G3-Slide Rail 3, K1-Slider 1, K2-Slider 2, K3-Slider 3, L1-Drive Short Rod 1, L2-Intermediate Rod, L3-Drive Short Rod 2, L4-Long Swing Rod 1, L5-U-shaped Fork 1, L6-Connecting Short Shaft 1, R1-Revolute Joint 1, R2-Revolute Joint 2, R3-Revolute Joint 3, R4-Revolute Joint 4, R5-Revolute Joint 5, R6-Revolute Joint 6, R7-Revolute Joint 7, R8-Revolute Joint 8, R9-Revolute Joint 9, Y1-Sliding Joint 1, Y2-Sliding Joint 2, Y3-Sliding Joint 3.

[0015] Figure 3 This is a schematic diagram of the third branch structure of the high-speed five-degree-of-freedom parallel robot based on the linkage of the sliding table and the defined axis of rotation, as described in Example 1 of the present invention.

[0016] G4 - Slide rail four, K4 - Slider four, L7 - Bearing seat one, L8 - Parallelogram short rod one, L9 - Parallelogram short rod two, L10 - Parallelogram long rod one, L11 - Parallelogram long rod two, L12 - Parallelogram short rod three, L13 - Parallelogram short rod four, L14 - Bearing seat two, R10 - Revolute joint ten, R11 - Revolute joint eleven, R12 - Revolute joint twelfth, R13 - Revolute joint thirteenth, R14 - Revolute joint fourteenth, R15 - Revolute joint fifteenth, R16 - Revolute joint sixteenth, R17 - Revolute joint seventeenth, R18 - Revolute joint eighteenth, Y4 - Sliding joint four. Detailed Implementation

[0017] In the following examples, the axis of rotation of the revolute joint refers to the center line around which the revolute joint rotates. The terms "up," "down," "left," "right," and "horizontal" are based on the orientations indicated in the accompanying drawings and are used for the convenience of describing the invention and for simplification, not to indicate or imply that the elements referred to must have a specific orientation.

[0018] The present invention relates to a high-speed five-degree-of-freedom parallel robot based on a linkage slide table and having a defined axis of rotation, which is described in detail below with reference to the accompanying drawings and examples:

[0019] This invention provides a high-speed five-degree-of-freedom parallel robot based on a linkage slide and having a defined axis of rotation, the structure of which is as follows: Figure 1 As shown, it includes a frame 1, a moving platform 2, an end effector 3, five drive motors, and first I, second II, and third III branches installed in parallel between the frame 1 and the moving platform 2.

[0020] One end of the first I, the second II, and the third III branches are connected at equal intervals to a circle centered on the center of the upper surface of the frame 1, and the other end is connected at equal intervals to a circle centered on the center of the upper surface of the moving platform 2, wherein the first branch I and the second branch II have the same structure.

[0021] The first branch I, from frame 1 to moving platform 2, is sequentially connected by a linkage slide rod assembly H1, a long swing rod L4, a U-shaped fork L5, and a connecting short shaft L6; the linkage slide rod assembly H1 consists of slide rail G1, slide rail G2, slide rail G3, slider K1, slider K2, slider K3, driving short rod L1, intermediate rod L2, driving short rod L3, revolute joint R1, revolute joint R2, revolute joint R3, revolute joint R4, revolute joint R5, prismatic joint Y1, prismatic joint Y2, and prismatic joint Y3; the linkage slide rod... Group 1 H1 is fixed on frame 1. The slider 1 K1 of the linkage group 1 H1 is connected to slide rail 1 G1 via sliding joint 1 Y1; slider 2 K2 is connected to slide rail 2 G2 via sliding joint 2 Y2; slider 3 K3 is connected to slide rail 3 G3 via sliding joint 3 Y3; drive short rod 1 L1 is connected to slider 2 K2 via revolute joint 1 R1; intermediate rod L2 is connected to drive short rod 1 L1 via revolute joint 2 R2; intermediate rod L2 is connected to slider 3 K3 via revolute joint 6 R6; intermediate rod L2 is connected to drive short rod 2 L3 via revolute joint 4 R4; and drive short rod 2 L3 is connected to… Slider K1 is connected via revolute joint 5 R5; long swing rod L4 is connected to intermediate rod L2 via revolute joint 6 R6; U-shaped fork L5 is connected to long swing rod L4 via revolute joint 7 R7; connecting short shaft L6 is connected to U-shaped fork L5 via revolute joint 8 R8; connecting short shaft L6 is connected to moving platform 2 via revolute joint 9 R9. Sliding joints Y1, Y2, and Y3 are parallel to each other and form a 60-degree angle with the plane of frame 1. The axis of revolute joint 1 R1 is perpendicular to sliding joint 2 Y2, and the axis of revolute joint 3 R3 is perpendicular to sliding joint 3 Y3. 3. The axis of rotary joint 5 R5 is perpendicular to the axis of prismatic joint 1 Y1. The axes of rotary joint 1 R1, rotary joint 2 R2, rotary joint 3 R3, rotary joint 4 R4, and rotary joint 5 R5 are parallel to each other. The axis of rotary joint 6 R6 is perpendicular to and intersects with the axis of rotary joint 3 R3. The axis of rotary joint 7 R7 is perpendicular to and intersects with the axis of rotary joint 6 R6. The axis of rotary joint 8 R8 is perpendicular to and intersects with the axis of rotary joint 7 R7. The axis of rotary joint 9 R9 is perpendicular to and intersects with the axis of rotary joint 8 R8. The axes of rotary joint 7 R7, rotary joint 8 R8, and rotary joint 9 R9 intersect.

[0022] The third branch III, from frame 1 to moving platform 2, is sequentially connected to a single-drive slide group H3 and a four-way universal joint parallelogram mechanism P. The single-drive slide group H3 consists of a slide rail G4, a slider K4, and a sliding joint Y4. The single-drive slide group H3 is fixed on frame 1. The slider K4 of the single-drive slide group H3 is connected to the slide rail G4 via the sliding joint Y4. The four-way universal joint parallelogram mechanism P consists of a bearing seat L7, a parallelogram short rod L8, a parallelogram short rod L9, a parallelogram long rod L10, a parallelogram long rod L11, a parallelogram short rod L12, a parallelogram short rod L13, a bearing seat L14, a revolute joint R10, and a revolute joint R11. Rotary joints 12 (R12), 13 (R13), 14 (R14), 15 (R15), 16 (R16), 17 (R17), and 18 (R18) together constitute the bearing housing 1 (L7) which is fixedly connected to the slider 4 (K4). Parallelogram short rod 1 (L8) is connected to bearing housing 1 (L7) via rotary joint 10 (R10). Parallelogram short rod 2 (L9) is connected to bearing housing 1 (L7) via rotary joint 11 (R11). Parallelogram long rod 1 (L10) is connected to parallelogram short rod 2 (L9) via rotary joint 12 (R12). Parallelogram long rod 2 (L11) is connected to parallelogram short rod 1 (L8) via rotary joint 13 (R13). Parallelogram short rod 3 (L12) is connected to parallelogram long rod 2 (L11) via rotary joint 13 (R13). The moving joint is connected by R14. Parallelogram short rod 3 L12 is connected to bearing housing 2 L14 via revolute joint R17. Bearing housing 2 L14 is connected to parallelogram short rod 4 L13 via revolute joint R16. Parallelogram short rod 4 L13 is connected to parallelogram long rod 1 L10 via revolute joint R15. Bearing housing 2 L14 is connected to moving platform 2 via revolute joint R18. The moving joint 4 Y4 forms a 60-degree angle with the plane of frame 1. The axes of revolute joint 10 R10 and revolute joint 11 R11 are collinear and perpendicular to moving joint 4 Y4. The axis of revolute joint 12 R12 is perpendicular to and intersects the axis of revolute joint 11 R11. The axis of revolute joint 13 R13 is perpendicular to and intersects the axis of revolute joint 11 R11 R12. The axes of revolute joints 11, 16 and 17 are collinear and parallel to the axes of revolute joints 10 and 11. The axis of revolute joint 14 is perpendicular to and intersects the axis of revolute joint 17. The axis of revolute joint 15 is perpendicular to and intersects the axis of revolute joint 16. The axes of revolute joints 12, 13, 14, and 15 are parallel to each other. The distance between the axes of revolute joints 12 and 13 is equal to the distance between the axes of revolute joints 14 and 15. The axis of revolute joint 18 is perpendicular to and intersects the axes of revolute joints 16 and 17.

[0023] The linkage slide group H1 is equipped with motors a and b, which together drive the movement and rotation of the intermediate rod L2 of the linkage slide group H1. The linkage slide group H2 is equipped with motors d and e, which together drive the movement and rotation of the drive rod L15 of the linkage slide group H2. The single drive slide group H3 is equipped with motor e, which drives the movement of the bearing seat L17 of the four-way universal joint parallelogram mechanism p. The four-way universal joint parallelogram mechanism P is replaced with a four-ball joint parallelogram mechanism. The end effector 3 is fixed to the moving platform 2 and, according to the working requirements, is a suction cup, assembly gripper, dispensing head, welding head, or spindle head.

Claims

1. A high-speed five-degree-of-freedom parallel robot based on a linkage slide and having a defined axis of rotation, belonging to the field of robot technology, comprising a frame, a moving platform, an end effector, five drive motors, and first, second, and third branches connected in parallel between the frame and the moving platform, characterized in that: One end of each of the first, second, and third branches is connected at equal intervals to a circle centered on the upper surface of the frame, and the other end is connected at equal intervals to a circle centered on the upper surface of the moving platform. The first branch has the same structure as the second branch. The first branch, from the frame to the moving platform, is sequentially connected to a first linkage slide rod assembly, a first long swing rod, a first U-shaped fork, and a first connecting short shaft. The first linkage slide rod assembly is fixed to the frame. The first long swing rod and the middle rod of the first linkage slide rod assembly are connected by a revolute joint six. The first U-shaped fork and the first long swing rod are connected by a revolute joint seven. The first connecting short shaft and the first U-shaped fork are connected by a revolute joint eight. The first connecting short shaft and the moving platform are connected by a revolute joint nine. The axis of the sixth revolute joint is parallel to the upper plane of the first linkage slide rod assembly. The axis of the seventh revolute joint is perpendicular to and intersects the axis of the sixth revolute joint. The axis of the eighth revolute joint is perpendicular to and intersects the axis of the seventh revolute joint. The axis of the ninth revolute joint is perpendicular to and intersects the axis of the sixth revolute joint. The axes of revolute joint 8, revolute joint 7, revolute joint 8, and revolute joint 9 intersect; the third branch III is sequentially connected from the frame to the moving platform with a single-drive slide group and a four-way universal joint parallelogram mechanism. The single-drive slide group is fixed to the frame, and the bearing seat 1 of the four-way universal joint parallelogram mechanism is fixed to the slider of the single-drive slide group. The bearing seat 2 of the four-way universal joint parallelogram mechanism is connected to the moving platform through revolute joint 18; motors 1 and 2 are installed on the linkage slide group 1 to jointly drive the movement and rotation of the intermediate rod of linkage slide group 1; motors 3 and 4 are installed on linkage slide group 2 to jointly drive the movement and rotation of the drive rod 3 of linkage slide group 2; motor 5 is installed on the single-drive slide group to drive the movement of the bearing seat 1 of the four-way universal joint parallelogram mechanism; the end effector is fixed to the moving platform and, according to the working requirements, is a suction cup, assembly gripper, dispensing head, welding head, or spindle head.

2. The high-speed five-degree-of-freedom parallel robot based on a linkage slide and having a defined axis of rotation as described in claim 1, characterized in that... The robot's third branch's four-way omnidirectional parallelogram mechanism was replaced with a four-ball-joint parallelogram mechanism.

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