A four-degree-of-freedom non-overconstrained parallel mechanism with identical branches

Abstract

The present invention relates to a robot. The purpose is to provide a four-degree-of-freedom non-overconstrained parallel mechanism with identical branches. The parallel mechanism should have the characteristics of structural symmetry, simple assembly, and good force-bearing performance. The technical solution is a four-degree-of-freedom non-overconstrained parallel mechanism with identical branches, comprising a frame, a moving platform, a first rotating pair, a second rotating pair, a first intermediate platform, a second intermediate platform, and four series branches with identical structures; wherein two series branches are connected in parallel between the frame and the first intermediate platform, and the other two series branches are connected in parallel between the frame and the second intermediate platform; the first intermediate platform is connected to the moving platform via a first rotating pair, and the second intermediate platform is connected to the moving platform via a second rotating pair; the first rotating pair axis and the second rotating pair axis are non-coplanar straight lines.

Description

Technical Field

[0001] The invention relates to a robot, in particular to a four-degree-of-freedom non-overconstrained parallel mechanism with identical branches. Background Art

[0002] The parallel mechanism is a closed-loop mechanism consisting of a moving platform, a frame, and multiple branches connected between the moving platform and the fixed platform. It has the advantages of compact structure, fast speed, high rigidity, high precision, and good dynamic characteristics. It is widely used in motion simulation, packaging sorting, mechanical processing and other fields.

[0003] Parallel mechanisms with three movements and one rotation are widely used in motion simulation, packaging sorting, mechanical processing and other fields; for example, CN114378792A, CN105729450A. However, there are overconstraints in these three movements and one rotation mechanisms; although the overconstraints can improve the rigidity of the mechanism, they have higher requirements on the precision of parts manufacturing and assembly. In the case of inevitable errors, there are internal forces inside the mechanism, which have an adverse effect on its strength and reliability. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a four-degree-of-freedom non-overconstrained parallel mechanism with the same branches. The parallel mechanism should have the characteristics of symmetrical structure, simple assembly and good force bearing performance.

[0005] The technical solution of the present invention is:

[0006] A four-degree-of-freedom non-overconstrained parallel mechanism with identical branches, comprising a frame, a moving platform, a first rotation pair, a second rotation pair, a first intermediate platform, a second intermediate platform, and four series branches with identical structures; wherein two series branches are connected in parallel between the frame and the first intermediate platform, and the other two series branches are connected in parallel between the frame and the second intermediate platform; the first intermediate platform is connected to the moving platform via a first rotation pair, and the second intermediate platform is connected to the moving platform via a second rotation pair; the axis of the first rotation pair and the axis of the second rotation pair are skew lines;

[0007] The series branch includes a mounting seat, a third rotation pair, a first connecting rod, a fourth rotation pair, a second connecting rod, a fifth rotation pair, a third connecting rod, a sixth rotation pair, a fourth connecting rod and a seventh rotation pair, which are sequentially connected between the frame and the first intermediate platform or sequentially connected between the frame and the second intermediate platform; or,

[0008] Each series branch includes a mounting seat, a third rotation pair, a first movement pair, a fifth rotation pair, a third connecting rod, a sixth rotation pair, a fourth connecting rod and a seventh rotation pair, which are sequentially connected between the frame and the first intermediate platform or sequentially connected between the frame and the second intermediate platform; wherein the axis of the first movement pair is perpendicular to the axis of the third rotation pair; or,

[0009] The series branch includes a second moving pair, a fourth rotating pair, a second connecting rod, a fifth rotating pair, a third connecting rod, a sixth rotating pair, a fourth connecting rod and a seventh rotating pair, which are sequentially connected between the frame and the first intermediate platform or sequentially connected between the frame and the second intermediate platform; wherein the axis of the second moving pair is perpendicular to the axis of the fourth rotating pair;

[0010] In each series branch, the fifth rotation secondary axis, the sixth rotation secondary axis and the seventh rotation secondary axis intersect at one point; among the four series branches, the line connecting the two intersection points in the two series branches connected to the first intermediate platform is parallel to the first rotation secondary axis, and the line connecting the two intersection points in the two series branches connected to the second intermediate platform is parallel to the second rotation secondary axis.

[0011] In the four series branches, the third rotation sub-axes are parallel to each other, the fourth rotation sub-axes are parallel to each other, and the third rotation sub-axis is parallel to the fourth rotation sub-axis.

[0012] The first moving pair is formed by the cooperation of a sleeve and a telescopic rod.

[0013] The second moving pair is formed by the cooperation of a moving pair guide rail and a sliding block.

[0014] The movable pair guide rail is fixed to the frame, and the slide block is connected to the fourth rotating pair.

[0015] The mounting seat is fixed to the frame.

[0016] The beneficial effects of the present invention are:

[0017] The parallel mechanism proposed in the present invention has the same series branches, no redundant constraints, and has the advantages of the same branches, simple assembly, good force performance, etc., and can be widely used in motion simulation, packaging sorting, mechanical processing and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional structure of the first embodiment of the present invention.

[0019] Figure 2 It is a schematic diagram of the three-dimensional structure of the second embodiment of the present invention.

[0020] Figure 3 It is a schematic diagram of the three-dimensional structure of embodiment 3 of the present invention.

[0021] Figure 4 It is a schematic diagram of the three-dimensional structure of the series branches in the first embodiment.

[0022] Figure 5 It is a schematic diagram of the three-dimensional structure of the series branches in the second embodiment.

[0023] Figure 6 It is a schematic diagram of the three-dimensional structure of the series branches in the third embodiment. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

[0025] Embodiment 1

[0026] like Figure 1 and Figure 4 The four-DOF non-overconstrained parallel mechanism with the same branches shown includes a frame (omitted in the figure), a moving platform 1, a first rotation pair 2, a second rotation pair 3, a first intermediate platform 4, a second intermediate platform 5, and four series branches with the same structure. Among them, two series branches are connected in parallel between the frame and the first intermediate platform, and the other two series branches are connected in parallel between the frame and the second intermediate platform. The first intermediate platform is connected to the moving platform through the first rotation pair, and the second intermediate platform is connected to the moving platform through the second rotation pair. The axis of the first rotation pair and the axis of the second rotation pair are skew lines.

[0027] The series branches include a mounting seat 6, a third rotation pair 7, a first connecting rod 8, a fourth rotation pair 9, a second connecting rod 10, a fifth rotation pair 11, a third connecting rod 12, a sixth rotation pair 13, a fourth connecting rod 14 and a seventh rotation pair 15, which are sequentially connected between the frame and the first intermediate platform or between the frame and the second intermediate platform. The mounting seat is fixed to the frame; for the four series branches, all the third rotation pair axes are parallel to each other, all the fourth rotation pair axes are parallel to each other, and the third rotation pair axis is parallel to the fourth rotation pair axis.

[0028] In each series branch, the fifth rotation secondary axis, the sixth rotation secondary axis and the seventh rotation secondary axis intersect at one point. In the two series branches connected to the first intermediate platform, the line connecting the two intersection points is parallel to the first rotation secondary axis. In the two series branches connected to the second intermediate platform, the line connecting the two intersection points is parallel to the second rotation secondary axis.

[0029] In this embodiment, the driving pair is selected from the rotating pair connected to the frame on each series branch, and the driving method can be a reduction motor (omitted in the figure); by controlling the movement of the driving pair, the platform can perform three movements and one rotation.

[0030] Embodiment 2

[0031] like Figure 2 and Figure 5 The four-degree-of-freedom non-overconstrained parallel mechanism with the same branches shown includes a frame (omitted in the figure), a moving platform 1, a first rotating pair 2, a second rotating pair 3, a first intermediate platform 4, a second intermediate platform 5, and four series branches with the same structure. The structure of the second embodiment is similar to that of the first embodiment, but the difference is that each series branch of the second embodiment includes a mounting seat 6, a third rotating pair 7, a sleeve 16, a telescopic rod 17 (the sleeve and the telescopic rod cooperate to form a first moving pair), a fifth rotating pair 11, a third connecting rod 12, a sixth rotating pair 13, a fourth connecting rod 14, and a seventh rotating pair 15, which are sequentially connected between the frame and the first intermediate platform or sequentially connected between the frame and the second intermediate platform. Among them, the axis of the first moving pair is perpendicular to the axis of the third rotating pair; the sleeve is connected to the third rotating pair, and the telescopic rod is connected to the fifth rotating pair.

[0032] Except for the above differences, the rest of the structure of this embodiment is the same as that of embodiment 1. The driving pair can be selected from the moving pair on each series branch, and the driving method can be selected from the ball screw (omitted in the figure); by controlling the movement of the driving pair, the movable platform can perform three movements and one rotation.

[0033] Embodiment 3

[0034] like Figure 3 and Figure 6 The four-degree-of-freedom non-overconstrained parallel mechanism with the same branches shown includes a frame (omitted in the figure), a moving platform 1, a first rotating pair 2, a second rotating pair 3, a first intermediate platform 4, a second intermediate platform 5, and four series branches with the same structure. The structure of the third embodiment is similar to that of the first embodiment, except that each series branch of the third embodiment includes a moving pair guide rail 18, a slider 19 (the slider cooperates with the moving pair guide rail to form a second moving pair), a fourth rotating pair 9, a second connecting rod 10, a fifth rotating pair 11, a third connecting rod 12, a sixth rotating pair 13, a fourth connecting rod 14, and a seventh rotating pair 15, which are sequentially connected between the frame and the first intermediate platform or sequentially connected between the frame and the second intermediate platform. Among them, the second moving pair axis is perpendicular to the fourth rotating pair axis; the moving pair guide rail is fixed to the frame, and the slider is connected to the fourth rotating pair 9.

[0035] Except for the above differences, the rest of the structure of this embodiment is the same as that of embodiment 1. The driving pair can be selected from the moving pair on each series branch, and the driving method can be selected from the ball screw (omitted in the figure); by controlling the movement of the driving pair, the movable platform can perform three movements and one rotation.

Claims

1. A four-degree-of-freedom non-overconstrained parallel mechanism with identical branches, comprising a frame, a moving platform (1), a first rotational pair (2), a second rotational pair (3), a first intermediate platform (4), a second intermediate platform (5), and four series branches with identical structures; wherein: Two series branches are connected in parallel between the frame and the first intermediate platform, and the other two series branches are connected in parallel between the frame and the second intermediate platform; the first intermediate platform is connected to the moving platform through a first rotating pair, and the second intermediate platform is connected to the moving platform through a second rotating pair; the first rotating pair axis and the second rotating pair axis are skew lines; The series branches include a mounting base (6) connected in sequence between the frame and the first intermediate platform or in sequence between the frame and the second intermediate platform, a third rotation pair (7), a first connecting rod (8), a fourth rotation pair (9), a second connecting rod (10), a fifth rotation pair (11), a third connecting rod (12), a sixth rotation pair (13), a fourth connecting rod (14) and a seventh rotation pair (15); or, Each series branch includes a mounting seat, a third rotation pair, a first movement pair, a fifth rotation pair, a third connecting rod, a sixth rotation pair, a fourth connecting rod and a seventh rotation pair, which are sequentially connected between the frame and the first intermediate platform or sequentially connected between the frame and the second intermediate platform; wherein the axis of the first movement pair is perpendicular to the axis of the third rotation pair; or, The series branch includes a second moving pair, a fourth rotating pair, a second connecting rod, a fifth rotating pair, a third connecting rod, a sixth rotating pair, a fourth connecting rod and a seventh rotating pair, which are sequentially connected between the frame and the first intermediate platform or sequentially connected between the frame and the second intermediate platform; wherein the axis of the second moving pair is perpendicular to the axis of the fourth rotating pair; In each series branch, the fifth rotation secondary axis, the sixth rotation secondary axis and the seventh rotation secondary axis intersect at one point; among the four series branches, the line connecting the two intersection points in the two series branches connected to the first intermediate platform is parallel to the first rotation secondary axis, and the line connecting the two intersection points in the two series branches connected to the second intermediate platform is parallel to the second rotation secondary axis.

2. The four-degree-of-freedom non-overconstrained parallel mechanism with the same branches according to claim 1, characterized in that: In the four series branches, the third rotation sub-axes are parallel to each other, the fourth rotation sub-axes are parallel to each other, and the third rotation sub-axis is parallel to the fourth rotation sub-axis.

3. The four-degree-of-freedom non-overconstrained parallel mechanism with identical branches according to claim 2, characterized in that: The first moving pair is formed by the cooperation of a sleeve (16) and a telescopic rod (17).

4. The four-degree-of-freedom non-overconstrained parallel mechanism with identical branches according to claim 3, characterized in that: The second moving pair is formed by the cooperation of a moving pair guide rail (18) and a sliding block (19).

5. The four-degree-of-freedom non-overconstrained parallel mechanism with identical branches according to claim 4, characterized in that: The movable pair guide rail is fixed to the frame, and the slide block is connected to the fourth rotating pair.

6. The four-degree-of-freedom non-overconstrained parallel mechanism with identical branches according to claim 5, characterized in that: The mounting seat is fixed to the frame.

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