A four-degree-of-freedom parallel robot with analytical positive solution and pitch rotation

Abstract

The present application relates to a kind of four-degree-of-freedom parallel robots with analytical positive solution and pitch rotation, belong to robot technical field, including fixed platform, mobile platform, end effector and parallelly connected between fixed platform and mobile platform first, second, third branch;The first, second branch structure is completely identical and symmetrically arranged, and first branch sequentially connected with active arm one, four universal hinge parallelogram mechanism from fixed platform to mobile platform;Third branch sequentially connected with parallelogram mechanism one, parallelogram mechanism two, U-shaped fork, connecting short shaft four, bearing seat two from fixed platform to mobile platform;Compared with prior art, the robot of the present application has analytical positive solution and is simple to solve, easy to combine with machine vision technology;Only three branches are used to realize three-dimensional movement and pitch rotation, and the structure is simple and compact, and the manufacturing cost is low;It has the advantages of large workspace, high speed, high precision, and can be widely applied in sorting, assembly and other fields.

Description

Technical Field

[0001] This invention relates to a four-degree-of-freedom parallel robot with analytical forward homing and pitch / rotation capabilities, belonging to the field of robotics technology. Background Technology

[0002] The degrees of freedom of a four-degree-of-freedom parallel robot include: three-dimensional translation plus one-dimensional rotation, two-dimensional translation plus two-dimensional rotation, one-dimensional translation plus three-dimensional rotation, etc. Among them, three-dimensional translation plus one-dimensional rotation includes: three-dimensional translation plus rotation and three-dimensional translation plus pitch rotation. Four-degree-of-freedom parallel robots with three-dimensional translation plus pitch rotation are not common. They can be widely used in sorting, assembly, processing and other fields to meet the needs of industrial production.

[0003] Chinese patent (CN 108274457 B) proposes a four-degree-of-freedom robot manipulator. The planar motion component realizes the up-and-down and forward-and-backward movements of the end effector, while the helical motion component realizes the left-and-right translation and flipping movements of the end effector. The entire manipulator is a hybrid structure, capable of neatly and efficiently stacking workpieces, but it is complex, occupies a large area, has poor flexibility, and requires high levels of assembly and daily maintenance. Chinese patent (CN 105234922 A) proposes a three-translational-one-rotation parallel robot device, providing two operating positions for user selection. It has advantages such as control decoupling and simple motion analysis. Although it has a kinematic analytical positive solution, the four-branch structure makes the links prone to interference, and the workspace is small. Chinese patent (CN 112743519)... A) A parallel mechanism with three spatial translations and one rotation, consisting of pitch and rotation, is proposed. It includes four drive chains supported at four different positions on the frame assembly. The sliders of the four drive chains are all set to move along mutually parallel straight lines. The mechanism has high stiffness, compact structure, and is easy to assemble, but it has a small workspace, is prone to singular configurations, and has a complex analytical forward solution.

[0004] The existing four-degree-of-freedom parallel robots of different types have the following problems: (1) Most four-degree-of-freedom parallel robots are three-dimensional translation plus rotation, and there are few robot configurations that can achieve three-dimensional translation plus pitch rotation; (2) Existing parallel robots with three-dimensional translation plus pitch rotation do not have analytical forward kinematics or the analytical forward kinematics is complex to calculate, making it difficult to combine with machine vision technology; (3) Existing parallel robots with three-dimensional translation plus pitch rotation have at least four branches, small workspace, and are prone to singular configurations, lacking three-branch schemes; (4) They cannot simultaneously have the advantages of simple and compact structure, simple analytical forward kinematics calculation, few kinematic branches, large workspace, and few singular configurations, and cannot meet the needs of industrial engineering applications.

[0005] This invention proposes a four-DOF parallel robot with analytical forward kinematics and pitch and rotation capabilities. It possesses analytical forward kinematics with simple calculations, making it easy to integrate with machine vision technology. The robot achieves three-dimensional movement plus pitch and rotation using only three branches, resulting in a simple and compact structure, low manufacturing cost, and convenient assembly and daily maintenance. All drive components are arranged on a fixed platform, with lightweight branches and end effectors, low inertia, and superior motion performance. Furthermore, the robot has fewer moving parts, offering advantages such as a large workspace, fewer singular configurations, high precision, and high speed, meeting the needs of scenarios such as food sorting and industrial assembly. Summary of the Invention

[0006] To address the above problems, this invention proposes a four-degree-of-freedom parallel robot with analytical forward homing and pitch rotation capabilities. The technical solution adopted to achieve the purpose of this invention is as follows:

[0007] A four-DOF parallel robot with analytical forward kinematics and pitch / rotation capabilities, belonging to the field of robot technology, includes a fixed platform, a moving platform, an end effector, four drive motors, and first, second, and third branches connected in parallel between the fixed and moving platforms. The first and second branches are characterized by their identical and symmetrical structures. The first branch, from the fixed platform to the moving platform, sequentially connects a revolute joint, an active arm, and a four-way parallelogram mechanism. One end of the active arm is connected to the fixed platform via the revolute joint, and the other end is connected to the four-way parallelogram mechanism via the revolute joint. The moving platform is fixedly connected to the four-way parallelogram mechanism. The end effector is mounted on the moving platform. The axis of the revolute joint is parallel to the plane of the fixed platform. The third branch, from the fixed platform to the moving platform, sequentially connects a parallelogram mechanism, a parallelogram mechanism, a U-shaped fork, a revolute joint seventeen, a connecting short shaft four, a revolute joint eighteen, and a bearing seat two. The input end of mechanism one is connected to the fixed platform via revolute joint eight and revolute joint nine. The output end of parallelogram mechanism one is fixedly connected to the input end of parallelogram mechanism two. Parallelogram mechanism two and parallelogram mechanism one share a Y-shaped connecting rod. The U-shaped fork is fixedly connected to the output end of parallelogram mechanism two. The connecting short shaft four is connected to the U-shaped fork via revolute joint seventeen. The bearing seat two is connected to the connecting short shaft four via revolute joint eighteen. The plane where parallelogram mechanism one is located is perpendicular to the plane where parallelogram mechanism two is located. The axis of revolute joint seventeen is perpendicular to and intersects the axis of revolute joint eighteen. The axis of revolute joint eighteen is parallel to the plane of the moving platform. Four motors are installed on the fixed platform. Motor one and motor two drive the movement of the active arm one of branch one and the active arm one of branch two, respectively. Motor three and motor four jointly drive the movement of parallelogram mechanism one. The four universal joint parallelogram mechanism in the first branch and the second branch is replaced with a four ball joint parallelogram mechanism.

[0008] The beneficial effects of the technical solution of the present invention are as follows: the robot has a kinematic analytical forward solution and the solution is simple, making it easy to combine with machine vision technology; it achieves three-dimensional movement plus pitch and rotation using only three branches, with a simple and compact structure, low manufacturing cost, and convenient assembly and daily maintenance; all drive components are arranged on a fixed platform, the branches and end effector are lightweight, the mechanism has low inertia, and excellent motion performance; at the same time, the robot has fewer moving parts, and has the advantages of large working space, few singular configurations, high speed, and high precision. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the overall structure of a four-degree-of-freedom parallel robot with analytical forward calculus and pitch and rotation according to the present invention.

[0010] Figure 2 This is a schematic diagram of the first branch of a four-degree-of-freedom parallel robot with analytical forward inequality and pitch rotation according to the present invention.

[0011] Figure 3 This is a schematic diagram of the third branch of a four-degree-of-freedom parallel robot with analytical forward calculus and pitch and rotation capabilities according to the present invention.

[0012] Among them, 1-fixed platform, 2-moving platform, 3-end effector, a-motor one, b-motor two, c-motor three, d-motor four, Ⅰ-first branch, Ⅱ-second branch, Ⅲ-third branch, W-four universal joint parallelogram mechanism, P1-parallelogram mechanism one, P2-parallelogram mechanism two, L1-drive arm one, L2-connecting short shaft one, L3-long connecting rod one, L4-long connecting rod two, L5-bearing seat one, L6-connecting short shaft two, L7-drive arm two, L8-drive arm three, L9-short connecting rod, L10-Y-shaped connecting rod, L11-long connecting rod three, L12-long connecting rod four, L13-connecting short shaft three, L 14-U-shaped fork, L15-Connecting short shaft four, L16-Bearing seat two, L17-Active arm four, R1-Revolute joint one, R2-Revolute joint two, R3-Revolute joint three, R4-Revolute joint four, R5-Revolute joint five, R6-Revolute joint six, R7-Revolute joint seven, R8-Revolute joint eight, R9-Revolute joint nine, 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, R19-Revolute joint nineteenth, R20-Revolute joint twentieth. Detailed Implementation

[0013] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0014] In the examples described below, the axis of rotation of the revolute joint refers to the center line around which the revolute joint rotates. The terms "up," "down," "left," and "right" 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.

[0015] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixed connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0016] This invention proposes a four-degree-of-freedom parallel robot with analytical forward homing and pitch / rotation capabilities, the structure of which is as follows: Figure 1 As shown, it includes a fixed platform 1, a moving platform 2, an end effector 3, four drive motors a, b, c, and d, and a first branch I, a second branch II, and a third branch III connected in parallel between the fixed platform 1 and the moving platform 2.

[0017] The first branch I and the second branch II have identical structures and are symmetrically arranged. The first branch I, from the fixed platform 1 to the moving platform 2, is sequentially connected by a revolute joint R1, an active arm L1, and a four-way universal joint parallelogram mechanism W. One end of the active arm L1 is connected to the fixed platform 1 via the revolute joint R1, and the other end is connected to the four-way universal joint parallelogram mechanism W via the revolute joint R2. The four-way universal joint parallelogram mechanism W consists of a connecting short shaft L2, a long connecting rod L3, a long connecting rod L4, a bearing seat L5, a connecting short shaft L6, a revolute joint R2, a revolute joint R3, a revolute joint R4, a revolute joint R5, a revolute joint R6, and a revolute joint R7. The connecting short shaft L2 is connected to the active arm L1 via the revolute joint R2, and the long connecting rods L3 and L4 are connected to the connecting short shaft L2 via the revolute joints R3 and R4, respectively. Long connecting rod 1 L3 and long connecting rod 2 L4 are connected to connecting short shaft 2 L6 via rotating joint 6 R6 and rotating joint 7 R7 respectively. Connecting short shaft 2 L6 is connected to bearing housing 1 L5 via rotating joint 5 R5. Bearing housing 1 L5 is fixedly connected to moving platform 2. The axis of rotating joint 1 R1 is parallel to the plane of fixed platform 1. The axis of rotating joint 2 R2 is parallel to the axis of rotating joint 1 R1. The axes of rotating joint 3 R3 and rotating joint 4 R4 are perpendicular to and intersect the axis of rotating joint 2 R2. The axes of rotating joint 6 R6 and rotating joint 7 R7 are perpendicular to and intersect the axis of rotating joint 5 R5. The axes of rotating joint 3 R3, rotating joint 4 R4, rotating joint 6 R6, and rotating joint 7 R7 are parallel to each other. The axis of rotating joint 5 R5 is parallel to the plane of moving platform 2. The axis of rotating joint 19 R19 of the second branch II is parallel to the axis of rotating joint 1 R1. The axis of rotating joint 20 R20 is parallel to the axis of rotating joint 5 R5.The third branch III, from the fixed platform 1 to the moving platform 2, is sequentially connected by parallelogram mechanism 1 P1, parallelogram mechanism 2 P2, U-shaped fork L14, revolute joint 17 R17, connecting short shaft 4 L15, revolute joint 18 R18, and bearing seat 2 L16. Parallelogram mechanism 1 P1 consists of active arm 2 L7, active arm 3 L8, short connecting rod L9, Y-shaped connecting rod L10, revolute joint 8 R8, revolute joint 9 R9, revolute joint 10 R10, revolute joint 11 R11, and revolute joint 12 R12. Active arm 2 L7 is connected to the fixed platform 1 via revolute joint 8 R8, and active arm 3 L8 is connected to the fixed platform 1 via revolute joint 9 R9. Short connecting rod L9... The Y-shaped link L10 is connected to the active arm L7 via revolute joint 10. The Y-shaped link L10 is connected to the short link L9 and the active arm L8 via revolute joint 11 R11 and revolute joint 12 R12, respectively. The parallelogram mechanism P2 consists of the Y-shaped link L10, long link L11 and long link L12, connecting short shaft L13, revolute joint 13 R13, revolute joint 14 R14, revolute joint 15 R15, and revolute joint 16 R16. Parallelogram mechanism P2 and parallelogram mechanism P1 share the Y-shaped link L10. Long link L11 and long link L12 are connected to the Y-shaped link L9 via revolute joint 13 R13 and revolute joint 14 R14, respectively. 10. Long connecting rods 3 L11 and 4 L12 are connected to connecting short shaft 3 L13 via revolute joints 16 R16 and 15 R15, respectively. U-shaped fork L14 is fixedly connected to connecting short shaft 3 L13. Connecting short shaft 4 L15 is connected to U-shaped fork L14 via revolute joint 17 R17. Bearing seat 2 L16 is connected to connecting short shaft 4 L15 via revolute joint 18 R18. Bearing seat 2 L16 is fixedly connected to moving platform 2. End effector 3 is mounted on moving platform 2. The plane where parallelogram mechanism 1 P1 is located is perpendicular to the plane where parallelogram mechanism 2 P2 is located. The axes of revolute joints 8 R8 and 9 R9 are parallel to fixed platform 1. In the plane, the axis of revolute joint 8 (R8) is parallel to the axis of revolute joint 1 (R1). The axes of revolute joint 8 (R8), revolute joint 9 (R9), revolute joint 10 (R10), revolute joint 11 (R11), and revolute joint 12 (R12) are parallel to each other. The axis of revolute joint 13 (R13) is perpendicular to the axis of revolute joint 12 (R12). The axes of revolute joint 13 (R13), revolute joint 14 (R14), revolute joint 15 (R15), and revolute joint 16 (R16) are parallel to each other. The axis of revolute joint 17 (R17) is perpendicular to the axis of revolute joint 16 (R16). The axis of revolute joint 18 (R18) is perpendicular to and intersects the axis of revolute joint 17 (R17). The axis of revolute joint 18 (R18) is parallel to the axis of revolute joint 5 (R5).

[0018] Four motors are installed on the fixed platform 1. Motor 1a and motor 2b drive the rotation of the first active arm L1 and the fourth active arm L17, respectively. Motor 3c and motor 4d drive the rotation of the second active arm L7 and the third active arm L8, respectively. The four universal joint parallelogram mechanism is replaced with a four ball joint parallelogram mechanism.

Claims

1. A four-degree-of-freedom parallel robot with analytical forward kinematics and pitch / rotation capabilities, belonging to the field of robot technology; comprising a fixed platform, a moving platform, an end effector, four drive motors, and first, second, and third branches connected in parallel between the fixed platform and the moving platform, characterized in that: The first and second branches have identical structures and are symmetrically arranged. The first branch, from the fixed platform to the moving platform, is sequentially connected to a revolute joint one, an active arm one, and a four-way universal joint parallelogram mechanism. One end of the active arm one is connected to the fixed platform via revolute joint one, and the other end is connected to the four-way universal joint parallelogram mechanism via revolute joint two. The moving platform is fixedly connected to the four-way universal joint parallelogram mechanism. The end effector is mounted on the moving platform. The axis of revolute joint one is parallel to the plane of the fixed platform. The third branch, from the fixed platform to the moving platform, is sequentially connected to a parallelogram mechanism one, a parallelogram mechanism two, a U-shaped fork, a revolute joint seventeen, a connecting short shaft four, a revolute joint eighteen, and a bearing seat two. The input end of parallelogram mechanism one is connected to the fixed platform via revolute joint eight and revolute joint nine. The output end of parallelogram mechanism one is fixedly connected to the input end of parallelogram mechanism two. Parallelogram mechanism two and parallelogram mechanism one share a Y-shaped connecting rod. The U-shaped fork is fixedly connected to the output end of parallelogram mechanism two. The connecting short shaft four is connected to the U-shaped fork through revolute joint seventeen. The bearing seat two is connected to the connecting short shaft four through revolute joint eighteen. The plane where parallelogram mechanism one is located is perpendicular to the plane where parallelogram mechanism two is located. The axis of revolute joint seventeen is perpendicular to and intersects the axis of revolute joint eighteen. The axis of revolute joint eighteen is parallel to the plane of the moving platform. Four motors are installed on the fixed platform. Motor one and motor two drive the movement of the active arm one of the first branch and the active arm one of the second branch, respectively. Motor three and motor four jointly drive the movement of parallelogram mechanism one.

2. The four-degree-of-freedom parallel robot with analytical forward calculus and pitch / rotation as described in claim 1, characterized in that, The four-way parallelogram mechanism of the first and second branches of the robot has been replaced with a four-ball-joint parallelogram mechanism.

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