Symmetrical two-translational one-rotational three-degree-of-freedom parallel mechanism

Abstract

This invention relates to a type of symmetrical two-transfer-one-helical three-degree-of-freedom parallel mechanism, comprising a fixed platform, a moving platform, and a first branch, a second branch, and a third branch connecting the fixed platform and the moving platform. The two ends of the first branch, the second branch, and the third branch are respectively connected to the endpoints of the fixed platform and the moving platform. Each of the first branch, the second branch, and the third branch is a PRR series branch composed of a first prismatic joint, a first revolute joint, a second prismatic joint, a first connecting rod, a second revolute joint, a second connecting rod, and a third revolute joint. This parallel mechanism, without using helical joints, achieves spatially independent two-dimensional translation and one-dimensional independent helical degree of freedom using only prismatic and revolute joints. Furthermore, it can control the independent helical motion at the end via linear drive, which not only improves the dynamic performance and load-bearing capacity of the mechanism but also has advantages such as a large working space, symmetrical structure, wide application range, and strong adaptability.

Description

Technical Field

[0001] This invention belongs to the field of parallel mechanism technology, and specifically relates to a type of symmetrical two-transfer one-helical three-degree-of-freedom parallel mechanism. Background Technology

[0002] Currently, parallel mechanisms containing independent helical motions are very rare. Only a few parallel mechanisms can achieve independent helical motions through bifurcated motions, and most of them directly achieve this using helical pairs, which severely affects the performance of the mechanism. Furthermore, these mechanisms employ asymmetrical structures or add extra constraint branches, lacking complete symmetry, resulting in complex structures and high manufacturing difficulty. They cannot meet the requirements of isotropic robots and three-degree-of-freedom motion (two translations and one helical motion) for tasks such as assembly, material handling, packaging, and sorting. Therefore, this invention provides a class of symmetrical two-translation and one-helical three-degree-of-freedom parallel mechanisms to solve the above problems. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a type of symmetrical two-transfer-one-helical three-degree-of-freedom parallel mechanism, which enriches the types of end motions of parallel mechanisms. It utilizes a combination of translating pairs and revolute pairs to achieve two-dimensional translation parallel to the moving platform and independent helical motion around any axis perpendicular to the fixed platform, without using helical pairs. This simplifies the structure, improves the dynamic performance and load-bearing capacity of the mechanism, and reduces the processing cost and manufacturing difficulty by using a fully symmetrical mechanism. This type of mechanism has advantages such as a large working space and easy control.

[0004] The technical solution adopted in this invention is a symmetrical two-transfer-one-screw three-degree-of-freedom parallel mechanism.

[0005] It includes a fixed platform, a moving platform, and three branches connecting the fixed platform and the moving platform. The fixed platform includes a first frame, a second frame, and a third frame, which are located in the same plane and whose first ends intersect at a point, with adjacent frames having the same included angle. The moving platform has an equilateral triangle structure, and the three branches connecting the fixed platform and the moving platform include a first branch, a second branch, and a third branch. The two ends of the first branch, the second branch, and the third branch are respectively connected to the endpoints of the fixed platform and the moving platform, and the first branch, the second branch, and the third branch are all driving branches. The first sliding joint in the first branch, the second branch, and the third branch are all driving joints. The first branch, the second branch, and the third branch are all composed of a first sliding joint and a first rotating joint. The PRRRR series branch consists of a first sliding joint, a second sliding joint, a first connecting rod, a second revolute joint, a second connecting rod, and a third revolute joint. The first end of the first sliding joint is connected to the corresponding frame in the fixed platform, and the second end of the first sliding joint is connected to the first end of the second sliding joint through the first revolute joint. The axis of the first revolute joint coincides with that of the second sliding joint. The first sliding joint, the first revolute joint, and the second sliding joint are all located in the plane of the fixed platform. The second end of the second sliding joint is connected to the first end of the first connecting rod, and the second end of the first connecting rod is connected to the first end of the second connecting rod through the second revolute joint. The second end of the second connecting rod is connected to the corresponding endpoint in the moving platform through the third revolute joint. The axes of the third revolute joint in the first branch, the second branch, and the third branch intersect at a point.

[0006] Furthermore, the first prismatic joint is perpendicular to the axis of the first revolute joint, the second prismatic joint is perpendicular to the first connecting rod, the axes of the first connecting rod, the second revolute joint, and the second connecting rod coincide, and the second connecting rod is perpendicular to the axis of the third revolute joint.

[0007] The second aspect of the present invention adopts a symmetrical two-transfer-one-helical three-degree-of-freedom parallel mechanism, which includes a fixed platform, a moving platform, and three branches connecting the fixed platform and the moving platform. The fixed platform includes a first frame, a second frame, and a third frame, which are located in the same plane and whose first ends intersect at a point, with the included angle between adjacent frames being the same. The moving platform is an equilateral triangle, and the three branches connecting the fixed platform and the moving platform include a first branch, a second branch, and a third branch. The two ends of the first branch, the second branch, and the third branch are respectively connected to the endpoints of the fixed platform and the moving platform, and the first branch, the second branch, and the third branch are all driving branches. The first moving joints in the first branch, the second branch, and the third branch are all driving joints. All three branches are PPRRR series branches consisting of a first prismatic joint, a second prismatic joint, a first revolute joint, a first connecting rod, a second revolute joint, a second connecting rod, and a third revolute joint. The first end of the first prismatic joint is connected to the corresponding frame in the fixed platform, and the second end of the first prismatic joint is connected to the first end of the second prismatic joint. The second end of the second prismatic joint is connected to the first end of the first connecting rod through the first revolute joint. The axis of the first revolute joint is parallel to the first prismatic joint, and the first prismatic joint, the second prismatic joint, and the first revolute joint are all located in the plane of the fixed platform. The second end of the first connecting rod is connected to the first end of the second connecting rod through the second revolute joint, and the second end of the second connecting rod is connected to the corresponding endpoint in the moving platform through the third revolute joint. The axes of the third revolute joints in the first branch, the second branch, and the third branch intersect at a single point.

[0008] Furthermore, the first prismatic joint is perpendicular to the second prismatic joint, the first revolute joint is perpendicular to the first connecting rod, the second revolute joint is perpendicular to the first connecting rod and the second connecting rod, and the second connecting rod is perpendicular to the axis of the third revolute joint.

[0009] The features and beneficial effects of this invention are:

[0010] 1. The present invention provides a type of symmetrical two-transfer-one-helical three-degree-of-freedom parallel mechanism, which can realize the helical motion of the end platform by using only the translating pair and the revolute pair without using the helical pair. Furthermore, it can control the independent helical motion of the end platform by linear drive, thereby simplifying the structure and improving the dynamic performance and load-bearing capacity of the mechanism.

[0011] 2. The present invention provides a type of symmetrical two-transfer one-helical three-degree-of-freedom parallel mechanism, which adopts a fully symmetrical mechanism to reduce the processing cost and manufacturing difficulty. It has the advantages of large working space, symmetrical structure and easy control. At the same time, this mechanism can also be applied to robotic equipment such as assembly, material handling, packaging and sorting, with a wide range of applications and strong adaptability. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of a symmetrical two-transfer-one-screw three-degree-of-freedom parallel mechanism of the present invention;

[0013] Figure 2a This is a top view of the initial pose of Embodiment 1 of the present invention;

[0014] Figure 2b This is a schematic diagram of the moving platform translating along the X direction from its initial pose in Embodiment 1 of the present invention;

[0015] Figure 2c This is a schematic diagram of the moving platform translating along the Y direction from its initial pose in Embodiment 1 of the present invention;

[0016] Figure 2d This is a schematic diagram of the moving platform translating in any direction parallel to the fixed platform 1 in Embodiment 1 of the present invention;

[0017] Figure 2e This is a side view of the initial pose of Embodiment 1 of the present invention;

[0018] Figure 2f This is a schematic diagram of the moving platform spiraling along the Z direction from an initial pose in Embodiment 1 of the present invention;

[0019] Figure 2g This is a schematic diagram of the general pose of Embodiment 1 of the present invention;

[0020] Figure 3 This is a schematic diagram of the working space of Embodiment 1 of a symmetrical two-transfer-one-screw three-degree-of-freedom parallel mechanism of the present invention;

[0021] Figure 4 This is a schematic diagram of the structure of Embodiment 2 of a symmetrical two-transfer one-screw three-degree-of-freedom parallel mechanism of the present invention.

[0022] Key reference numerals:

[0023] Fixed platform 1; First frame A1; Second frame A2; Third frame A3; Moving platform 2; First branch 3; Second branch 4; Third branch 5; Sliding joint P; Rotating joint R; Universal joint U; Connecting rod L. Detailed Implementation

[0024] To fully describe the technical content, structural features, objectives, and effects of this invention, a detailed description will be provided below in conjunction with the accompanying drawings.

[0025] Example 1

[0026] The present invention provides a symmetrical two-transfer-one-screw three-degree-of-freedom parallel mechanism, such as... Figure 1 As shown, it includes a fixed platform 1, a moving platform 2, and three branches connecting the fixed platform 1 and the moving platform 2.

[0027] The fixed platform 1 includes a first frame A1, a second frame A2 and a third frame A3. The first frame A1, the second frame A2 and the third frame A3 are located in the same plane, and the first ends of the first frame A1, the second frame A2 and the third frame intersect at a point O1. The included angle between adjacent frames is the same. In a preferred embodiment, this same included angle is 120°.

[0028] The moving platform 2 is in the shape of an equilateral triangle, and the three branches connecting the fixed platform 1 and the moving platform 2 include the first branch 3, the second branch 4 and the third branch 5. The two ends of the first branch 3, the second branch 4 and the third branch 5 are respectively connected to the endpoints of the fixed platform 1 and the moving platform 2. The first branch 3, the second branch 4 and the third branch 5 are all driving branches, and the first sliding joint P1 in the first branch 3, the second branch 4 and the third branch 5 are all driving joints.

[0029] The first branch 3, the second branch 4, and the third branch 5 are all PRRRR series branches composed of the first prismatic joint P1, the first rotary joint R1, the second prismatic joint P2, the first connecting rod L1, the second rotary joint R2, the second connecting rod L2, and the third rotary joint R3. The first end of the first prismatic joint P1 is connected to the corresponding frame in the fixed platform 1, and the second end of the first prismatic joint P1 is connected to the first end of the second prismatic joint P2 through the first rotary joint R1. The first prismatic joint P1 is perpendicular to the axis of the first rotary joint R1, and the axis of the first rotary joint R1 coincides with the axis of the second prismatic joint P2. The first prismatic joint P1, the first rotary joint R1, and the second prismatic joint P2 form a series connection. All joints P2 are located in the plane of the fixed platform 1. The second end of the second sliding joint P2 is connected to the first end of the first link L1. The second sliding joint P2 is perpendicular to the first link L1, and the second end of the first link L1 is connected to the first end of the second link L2 through the second revolute joint R2. The axes of the first link L1, the second revolute joint R2 and the second link L2 coincide. The second end of the second link L2 is connected to the corresponding endpoint in the moving platform 2 through the third revolute joint R3, and the second link L2 is perpendicular to the axis of the third revolute joint R3. The axes of the third revolute joint R3 in the first branch 3, the second branch 4 and the third branch 5 intersect at a point O2.

[0030] This invention discloses a type of symmetrical two-transfer-one-helical three-degree-of-freedom parallel mechanism, in which the first branch 3, the second branch 4, and the third branch 5 are all driving branches. The first translational joint P1 in the first branch 3, the second branch 4, and the third branch 5 serves as the active driving joint, and the moving platform 2 serves as the end effector. As shown in Figure 2. Figure 2a This is a top view of the initial pose of an embodiment 1 of a symmetrical two-transfer-one-helical three-degree-of-freedom parallel mechanism of the present invention. When the active drive pair is controlled to move, the moving platform 2 can perform two-dimensional independent movements parallel to the fixed platform 1, for example... Figure 2b , Figure 2c and Figure 2d These are schematic diagrams showing the translation of the moving platform 2 from its initial pose along the X direction, Y direction, and any direction parallel to the fixed platform 1. Figure 2e This is a side view of the initial pose of an embodiment 1 of a symmetrical two-transfer-one-helical three-degree-of-freedom parallel mechanism of the present invention. When the active drive pair is controlled to move, the moving platform 2 can perform a one-dimensional independent helical motion perpendicular to the fixed platform 1, for example... Figure 2f This is a schematic diagram of the moving platform 2 spiraling along the Z direction from its initial pose. Figure 2g This is a schematic diagram of a typical embodiment of the symmetrical two-transfer-one-helical three-degree-of-freedom parallel mechanism of the present invention in a general pose. The working space of the moving platform 2 is relatively large, such as... Figure 3 The diagram shown is a schematic diagram of the working space of a type of symmetrical two-transfer one-screw three-degree-of-freedom parallel mechanism according to the present invention. It has a large working space, a symmetrical structure, and is easy to control.

[0031] Example 2

[0032] The technical solution adopted in the second aspect of the present invention, as shown in FIG2, includes a fixed platform 1, a moving platform 2, and three branches connecting the fixed platform 1 and the moving platform 2.

[0033] The fixed platform includes a first frame A1, a second frame A2 and a third frame A3. The first frame A1, the second frame A2 and the third frame A3 are located in the same plane, and the first ends of the first frame A1, the second frame A2 and the third frame intersect at a point O1. The included angle between adjacent frames is the same, and in a preferred embodiment, this same included angle is 120°.

[0034] The moving platform 2 is in the shape of an equilateral triangle, and the three branches connecting the fixed platform 1 and the moving platform 2 include the first branch 3, the second branch 4 and the third branch 5. The two ends of the first branch 3, the second branch 4 and the third branch 5 are respectively connected to the endpoints of the fixed platform 1 and the moving platform 2. The first branch 3, the second branch 4 and the third branch 5 are all driving branches, and the first sliding joint P1 in the first branch 3, the second branch 4 and the third branch 5 are all driving joints.

[0035] The first branch 3, the second branch 4, and the third branch 5 are all PPRRR series branches composed of the first prismatic joint P1, the second prismatic joint P2, the first rotary joint R1, the first connecting rod L1, the second rotary joint R2, the second connecting rod L2, and the third rotary joint R3. The first end of the first prismatic joint P1 is connected to the corresponding frame in the fixed platform 1, and the second end of the first prismatic joint P1 is connected to the first end of the second prismatic joint P2. The first prismatic joint P1 is perpendicular to the second prismatic joint P2. The second end of the second prismatic joint P2 is connected to the first end of the first connecting rod L1 through the first rotary joint R1. The axis of the first rotary joint R1 is parallel to the first prismatic joint P2. The moving P1 joint, and the first prismatic joint P1, the second prismatic joint P2 and the first revolute joint R1 are all located in the plane of the fixed platform 1. The first revolute joint R1 is perpendicular to the first link L1. The second end of the first link L1 is connected to the first end of the second link L2 through the second revolute joint R2. The second revolute joint R2 is perpendicular to the first link L1 and the second link L2. The second end of the second link L2 is connected to the corresponding end point in the moving platform 2 through the third revolute joint R3. The second link L2 is perpendicular to the axis of the third revolute joint R3. The axes of the third revolute joint R3 in the first branch 3, the second branch 4 and the third branch 5 intersect at a point O2.

[0036] The present invention relates to a type of symmetrical two-transfer-one-helical three-degree-of-freedom parallel mechanism, wherein the first branch 3, the second branch 4, and the third branch 5 are all driving branches. The first translating pair P1 in the first branch 3, the second branch 4, and the third branch 5 serves as the active driving pair, and the moving platform 2 serves as the end effector. When the active driving pair is controlled to move, the moving platform 2 can perform two-dimensional independent movement parallel to the fixed platform 1 and one-dimensional independent helical movement around any axis perpendicular to the fixed platform 1. The working space of the moving platform 2 is relatively large.

[0037] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A symmetrical two-transfer-one-screw three-degree-of-freedom parallel mechanism, characterized in that, It includes a fixed platform, a moving platform, and three branches connecting the fixed platform and the moving platform. The fixed platform includes a first frame, a second frame, and a third frame. The first frame, the second frame, and the third frame are located in the same plane, and the first ends of the first frame, the second frame, and the third frame intersect at a point. The included angle between adjacent frames is the same. The moving platform has an equilateral triangle structure, and the three branches connecting the fixed platform and the moving platform include a first branch, a second branch and a third branch. The two ends of the first branch, the second branch and the third branch are respectively connected to the endpoints of the fixed platform and the moving platform. The first branch, the second branch and the third branch are all driving branches, and the first sliding joint in the first branch, the second branch and the third branch are all driving joints. The first branch, the second branch, and the third branch are all PPRR series branches composed of a first prismatic joint, a first rotary joint, a second prismatic joint, a first connecting rod, a second rotary joint, a second connecting rod, and a third rotary joint. The first end of the first prismatic joint is connected to the corresponding frame in the fixed platform, and the second end of the first prismatic joint is connected to the first end of the second prismatic joint through the first rotary joint. The axis of the first rotary joint and the second prismatic joint coincide. The first prismatic joint, the first rotary joint, and the second prismatic joint are all located in the plane of the fixed platform. The second end of the second prismatic joint is connected to the first end of the first connecting rod, and the second end of the first connecting rod is connected to the first end of the second connecting rod through the second rotary joint. The second end of the second connecting rod is connected to the corresponding endpoint in the moving platform through the third rotary joint. The axes of the third rotary joints in the first branch, the second branch, and the third branch intersect at one point. The first sliding joint is perpendicular to the axis of the first rotating joint, the second sliding joint is perpendicular to the first connecting rod, the axes of the first connecting rod, the second rotating joint, and the second connecting rod are collinear, and the second connecting rod is perpendicular to the axis of the third rotating joint.

2. A symmetrical three-degree-of-freedom parallel mechanism with two translations and one helical component, characterized in that: It includes a fixed platform, a moving platform, and three branches connecting the fixed platform and the moving platform. The fixed platform includes a first frame, a second frame, and a third frame. The first frame, the second frame, and the third frame are located in the same plane, and the first ends of the first frame, the second frame, and the third frame intersect at a point. The included angle between adjacent frames is the same. The moving platform is in the shape of an equilateral triangle, and the three branches connecting the fixed platform and the moving platform include a first branch, a second branch and a third branch. The two ends of the first branch, the second branch and the third branch are respectively connected to the endpoints of the fixed platform and the moving platform, and the first branch, the second branch and the third branch are all driving branches, and the first sliding joint in the first branch, the second branch and the third branch are all driving joints. The first branch, the second branch, and the third branch are all PPRRR series branches composed of a first prismatic joint, a second prismatic joint, a first revolute joint, a first connecting rod, a second revolute joint, a second connecting rod, and a third revolute joint. The first end of the first prismatic joint is connected to the corresponding frame in the fixed platform, and the second end of the first prismatic joint is connected to the first end of the second prismatic joint. The second end of the second prismatic joint is connected to the first end of the first connecting rod through the first revolute joint. The axis of the first revolute joint is parallel to the first prismatic joint, and the first prismatic joint, the second prismatic joint, and the first revolute joint are all located in the plane of the fixed platform. The second end of the first connecting rod is connected to the first end of the second connecting rod through the second revolute joint, and the second end of the second connecting rod is connected to the corresponding endpoint in the moving platform through the third revolute joint. The axes of the third revolute joints in the first branch, the second branch, and the third branch intersect at a point.

3. The symmetrical two-transfer-one-screw three-degree-of-freedom parallel mechanism according to claim 2, characterized in that, The first prismatic joint is perpendicular to the second prismatic joint, the axis of the first revolute joint is perpendicular to the first connecting rod, the axis of the second revolute joint is perpendicular to the first connecting rod and the second connecting rod, and the second connecting rod is perpendicular to the axis of the third revolute joint.

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