WO2022117117A1

WO2022117117A1 - Four-degree-of-freedom completely-decoupled compound-drive parallel mechanism

Info

Publication number: WO2022117117A1
Application number: PCT/CN2021/142599
Authority: WO
Inventors: 吴孟丽; 吕东洋; 林玉飞; 李德祚; 李明宇; 王旭浩; 唐杰; 张军
Original assignee: 中国民航大学
Priority date: 2020-12-01
Filing date: 2021-12-29
Publication date: 2022-06-09
Also published as: CN112518721A; CN112518721B

Abstract

A four-degree-of-freedom completely-decoupled compound-drive parallel mechanism. The mechanism comprises a base, a movable platform, a first branch chain, a second branch chain and a third branch chain, and has three degrees of freedom of translation and one degree of freedom of rotation. The present invention has the following advantages: each of the four degrees of freedom of the mechanism is completely controlled by a single kinematic pair, complete decoupling is achieved, and theoretical analysis and control system development on the mechanism are greatly simplified; two driving pairs are used for a branch chain of the mechanism on a rack, compound drive is used, the number of branch chains is reduced, interference between the branch chains is avoided, the number of parts is reduced, and the manufacturing cost is further reduced; and the mechanism uses a double-parallelogram branch chain to replace a common multi-revolute-pair decoupling branch chain, such that motion stability is improved, and rigidity of the mechanism is improved.

Description

A fully decoupled compound drive parallel mechanism with four degrees of freedom

technical field

The invention belongs to the technical field of parallel mechanisms, in particular to a four-degree-of-freedom completely decoupled compound drive parallel mechanism.

Background technique

The structure of the parallel mechanism is a plurality of series branch chains connecting the dynamic and static platforms, which has the advantages of high rigidity, high speed and high precision; and in the field of processing, the parallel mechanism has the advantages of easy modularization and high versatility, which is the most important part of the manufacturing industry in my country. One of the breakthroughs to high-end progress.

Parallel mechanism is a research hotspot at home and abroad, but because of its strong coupling due to its structural characteristics, the structure of multi-spindle machine tools is more complex, and the difficulty of control system development and the problem of accuracy are the main bottlenecks restricting the development of parallel mechanisms in the processing field, and complete decoupling is achieved. It can solve the above problems, but the existing fully decoupled parallel mechanism has a complex structure, a large number of kinematic pairs in the branch chain, and few degrees of freedom, so it has little engineering value, and mostly only exists in the theoretical stage; It can reduce the number of branches and greatly reduce the complexity of the mechanism. Therefore, it will be a revolutionary progress in the manufacturing industry to propose a fully decoupled compound drive parallel mechanism suitable for processing and manufacturing.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention aims to provide a fully decoupled compound drive parallel mechanism with four degrees of freedom.

In order to achieve the above object, the fully decoupled compound drive parallel mechanism with four degrees of freedom provided by the present invention includes a base, a moving platform, a first branch, a second branch and a third branch;

Wherein, the base includes a first rail, a second rail, a third rail, a rack and a bottom plate; the first rail and the second rail are fixed on the surface of the bottom plate in a T-shape; the lower end of the rack is fixed on the bottom of the bottom plate surface, and the first track is located on both sides of the second track respectively; the third track is fixed on the rack facing the side of the first track and is perpendicular to the bottom plate;

The moving platform includes a first hinged support, a second hinged support, a third hinged support and a table board; the first hinged support is fixed in the middle of the bottom surface of the table board; the second hinged support and the third hinged support are respectively set In the middle of both sides of the platen; the rotation axis of the first hinged support is parallel to the bottom surface of the platen and parallel to the rotation axis of the second hinged support; the rotation axis of the third hinged support is parallel to the rotation axis of the first hinged support The axis of rotation is vertical and parallel to the side of the platen;

The first branch chain includes a first slider, a first link and a second link; the first slider is connected to the first track through the first moving pair; the first link and the second link have the same structure, and The rotation axes of the two ends are parallel, and one end of the first connecting rod is connected to the top surface of the first sliding block through the first rotating pair, and the other end is connected to one end of the second connecting rod through the second rotating pair, and the second connecting rod The other end is connected to the second hinged support of the moving platform through the third rotating pair; and the rotation axes of the first rotating pair, the second rotating pair and the third rotating pair are all parallel to the first track;

The second branch chain includes a second sliding block, two third connecting rods, two fourth connecting rods, a fifth connecting rod and a sixth connecting rod; the second sliding block is connected to the second connecting rod of the base through the second moving pair On the track; one end of the two third connecting rods are respectively connected to the top surface of the second sliding block through a fourth rotating pair, and the other end of each third connecting rod is simultaneously connected with the fifth rotating pair through a fifth rotating pair. One end of the connecting rod and one end of a fourth connecting rod are connected; the other ends of the two fourth connecting rods are respectively connected with the two ends of the sixth connecting rod through a sixth rotating pair; The rotation axes of the rotating pair and the sixth rotating pair are parallel to the second track, and the distance between each pair of rotating pairs is equal, so the second branch chain has a double-parallelogram structure as a whole;

The third branch chain includes a third sliding block, a connecting piece, a seventh connecting rod and an eighth connecting rod; the third sliding block is connected to the third track through the third moving pair; one end of the connecting piece is connected to the third rail through the seventh rotating pair On the top surface of the third slider, the other end is connected to one end of the seventh connecting rod through the eighth rotating pair, and the rotational axis of the seventh rotating pair is parallel to the first track; The rotation axes are perpendicular to each other; one end of the eighth link is connected with the other end of the seventh link through the ninth rotation pair, and the other end of the eighth link is connected to the third hinged support of the moving platform through the tenth rotation pair, And the rotation axes of the eighth rotation pair, the ninth rotation pair and the tenth rotation pair are parallel to each other.

The base is a circular plate-like structure.

The moving platform is a square plate-like structure.

The first connecting rod and the second connecting rod are rod-shaped structures with both ends in a bent state, and the bending directions of the two ends are opposite.

The fully decoupled compound drive parallel mechanism with four degrees of freedom provided by the present invention has the following advantages:

1. Each of the four degrees of freedom of the mechanism is completely controlled by a single motion pair, which realizes complete decoupling and greatly simplifies the theoretical analysis of the mechanism and the development of the control system.

2. The branch chain on the frame of this mechanism adopts two active pairs and adopts compound drive, which reduces the number of branch chains, avoids the interference between each branch chain, reduces the number of parts, and further reduces the manufacturing cost.

3. The mechanism adopts a double parallelogram branch chain, which replaces the general multi-rotation pair decoupling branch chain, which increases the motion stability and improves the rigidity of the mechanism.

Description of drawings

FIG. 1 is a schematic diagram of the overall structure of the fully decoupled compound drive parallel mechanism with four degrees of freedom provided by the present invention.

FIG. 2 is a schematic diagram of the base of the fully decoupled compound drive parallel mechanism with four degrees of freedom provided by the present invention.

FIG. 3 is a schematic diagram of a moving platform in a four-degree-of-freedom fully decoupled compound drive parallel mechanism provided by the present invention.

Fig. 4 is a schematic diagram of the first branch in the fully decoupled compound drive parallel mechanism with four degrees of freedom provided by the present invention.

FIG. 5 is a schematic diagram of the second branch in the fully decoupled compound drive parallel mechanism with four degrees of freedom provided by the present invention.

FIG. 6 is a schematic diagram of the third branch in the fully decoupled compound drive parallel mechanism with four degrees of freedom provided by the present invention.

Detailed ways

The fully decoupled compound drive parallel mechanism with four degrees of freedom provided by the present invention will be described in detail below with reference to the accompanying drawings.

As shown in Figure 1 - Figure 6, the four-degree-of-freedom fully decoupled compound drive parallel mechanism provided by the present invention comprises a base 1, a moving platform 2, a first branch I, a second branch II and a third branch III;

The base 1 includes a first rail 101, a second rail 102, a third rail 103, a rack 104 and a bottom plate 105; the first rail 101 and the second rail 102 are fixed on the surface of the bottom plate 105 in a T-shape The lower end of the rack 104 is fixed on the surface of the bottom plate 105, and is located on both sides of the second rail 102 with the first rail 101 respectively; the third rail 103 is fixed on the rack 104 facing the side of the first rail 101 and perpendicular to the bottom plate 105;

The moving platform 2 includes a first hinged support 201, a second hinged support 202, a third hinged support 203 and a table 204; the first hinged support 201 is fixed in the middle of the bottom surface of the table 204; the second hinged support 202 and the third hinged support 203 are respectively arranged in the middle of the two sides of the platen 204; the rotation axis of the first hinged support 201 is parallel to the bottom surface of the platen 204 and parallel to the rotation axis of the second hinged support 202; the third hinged support The rotation axis of the hinged support 203 is perpendicular to the rotation axis of the first hinged support 201, and is parallel to the side surface of the platen 204;

The first branch chain I includes a first sliding block 3, a first connecting rod 4 and a second connecting rod 5; the first sliding block 3 is connected to the first track 101 through the first moving pair 11; The two connecting rods 5 have the same structure, and the rotation axes at both ends are parallel. One end of the first connecting rod 4 is connected to the top surface of the first sliding block 3 through the first rotating pair 301 , and the other end is connected to the first sliding block 3 through the second rotating pair 302 . One end of the second connecting rod 5 is connected, and the other end of the second connecting rod 5 is connected to the second hinged support 202 of the moving platform 2 through the third rotating pair 15; and the first rotating pair 301 and the second rotating pair 302 and the rotation axis of the third rotating pair 15 is parallel to the first track 101;

The second branch II includes a second sliding block 404, two third connecting rods 405, two fourth connecting rods 406, a fifth connecting rod 407 and a sixth connecting rod 408; the second sliding block 404 passes through the second moving pair 12 is connected to the second track 102 of the base 1; one end of the two third links 405 is respectively connected to the top surface of the second slider 404 through a fourth rotating pair 401 at a distance, and each third link The other end of the 405 is connected with one end of the fifth link 407 and one end of a fourth link 406 through a fifth rotation pair 402; the other ends of the two fourth links 406 are respectively connected with a sixth rotation pair 403 It is connected with both ends of the sixth link 408; and the rotation axes of the fourth rotating pair 401, the fifth rotating pair 402 and the sixth rotating pair 403 are parallel to the second track 102, and the distance between each pair of rotating pairs is equal, so The second branch II has a double-parallelogram structure as a whole;

The third branch III includes a third sliding block 7, a connecting piece 8, a seventh connecting rod 9 and an eighth connecting rod 10; the third sliding block 7 is connected to the third track 103 through the third moving pair 13; the connecting piece 8 One end is connected to the top surface of the third slider 7 through the seventh rotating pair 501, the other end is connected to one end of the seventh link 9 through the eighth rotating pair 502, and the rotation axis of the seventh rotating pair 501 is parallel to the The first track 101; the rotation axes of the seventh rotating pair 501 and the eighth rotating pair 502 are perpendicular to each other; one end of the eighth connecting rod 10 and the other end of the seventh connecting rod 9 are connected by the ninth rotating pair 503, and the eighth connecting rod The other end of the 10 is connected to the third hinged support 203 of the moving platform 2 through the tenth rotation pair 16 , and the rotation axes of the eighth rotation pair 502 , the ninth rotation pair 503 and the tenth rotation pair 16 are parallel to each other.

The base 1 is a circular plate-like structure.

The moving platform 2 is a square plate-like structure.

The first connecting rod 4 and the second connecting rod 5 are rod-shaped structures with both ends in a bent state, and the bending directions of the two ends are opposite.

Taking the direction of the first track 101 as the x-axis direction, the direction of the second track 102 as the y-axis direction, and the direction of the third track 103 as the z-axis direction, the working principle of the fully decoupled compound drive parallel mechanism provided by the present invention is explained. as follows:

The fully decoupled compound drive parallel mechanism provided by the present invention selects the first moving pair 11 , the second moving pair 12 , the third moving pair 13 and the seventh rotating pair 501 as the active pair. The first slider 3 on the first branch chain I moves on the first track 101 to provide the moving platform 2 with a degree of freedom of movement in the x-axis direction; the second slider 404 on the second branch chain II moves on the second track 102 When moving up, it can provide the moving platform 2 with the freedom of movement in the y-axis direction; when the third slider 7 on the third branch III moves on the third track 103, it can provide the moving platform 2 with the freedom of movement in the z-axis direction , when the connecting member 8 on the third branch III rotates with the seventh rotating pair 501, it can provide the moving platform 2 with the rotational freedom around the x-axis direction, and finally, the moving platform 2 can realize the movement degrees of freedom in three directions and the surrounding There are four rotational degrees of freedom in the x-axis.

Claims

A four-degree-of-freedom fully decoupled compound drive parallel mechanism, characterized in that the parallel mechanism comprises a base (1), a moving platform (2), a first branch (I), a second branch (II) and The third branch (III);

Wherein, the base (1) includes a first rail (101), a second rail (102), a third rail (103), a rack (104) and a bottom plate (105); the first rail (101) and The second rail (102) is fixed on the surface of the bottom plate (105) in a T-shape; the lower end of the rack (104) is fixed on the surface of the bottom plate (105), and is located on the second rail (102) respectively with the first rail (101). ); the third rail (103) is fixed on the frame (104) facing the side of the first rail (101) and perpendicular to the bottom plate (105);

The moving platform (2) comprises a first hinged support (201), a second hinged support (202), a third hinged support (203) and a table plate (204); the first hinged support (201) is fixed on the table the middle of the bottom surface of the plate (204); the second hinged support (202) and the third hinged support (203) are respectively arranged in the middle of both sides of the platen (204); the rotation axes of the first hinged support (201) are parallel on the bottom surface of the platen (204) and parallel to the rotation axis of the second hinged support (202); the rotation axis of the third hinged support (203) is perpendicular to the rotation axis of the first hinged support (201), and parallel to the side of the platen (204);

The first branch chain (I) includes a first sliding block (3), a first connecting rod (4) and a second connecting rod (5); the first sliding block (3) is connected to the first sliding block (3) through the first moving pair (11). On a track (101); the first connecting rod (4) has the same structure as the second connecting rod (5), and the rotation axes of the two ends are parallel, wherein one end of the first connecting rod (4) passes through the first rotating pair (301) ) is connected to the top surface of the first slider (3), the other end is connected to one end of the second connecting rod (5) through the second rotating pair (302), and the other end of the second connecting rod (5) is connected to the second connecting rod (5) through the first The three rotating pairs (15) are connected to the second hinged support (202) of the moving platform (2); and the rotation of the first rotating pair (301), the second rotating pair (302) and the third rotating pair (15) The axes are all parallel to the first track (101);

The second branch chain (II) includes a second slider (404), two third links (405), two fourth links (406), a fifth link (407) and a sixth link (408) ); the second sliding block (404) is connected to the second track (102) of the base (1) through the second moving pair (12); one end of the two third connecting rods (405) is respectively rotated through a fourth The pair (401) is connected to the top surface of the second sliding block (404) at a distance, and the other end of each third link (405) is simultaneously connected with the fifth link (407) through a fifth rotating pair (402). One end of the connecting rod and one end of a fourth connecting rod (406) are connected; the other ends of the two fourth connecting rods (406) are connected with two ends of the sixth connecting rod (408) through a sixth rotating pair (403) respectively. and the rotation axes of the fourth rotating pair (401), the fifth rotating pair (402) and the sixth rotating pair (403) are parallel to the second track (102), and the distance between each pair of rotating pairs is equal, so the second The branch II has a double-parallelogram structure as a whole;

The third branch chain (III) includes a third sliding block (7), a connecting piece (8), a seventh connecting rod (9) and an eighth connecting rod (10); the third sliding block (7) passes through the third moving pair (13) is connected to the third track (103); one end of the connecting piece (8) is connected to the top surface of the third slider (7) through the seventh rotating pair (501), and the other end is connected to the top surface of the third sliding block (7) through the eighth rotating pair ( 502) is connected with one end of the seventh connecting rod (9), and the rotation axis of the seventh rotating pair (501) is parallel to the first track (101); the seventh rotating pair (501) and the eighth rotating pair (502) The rotation axes of the eighth link (10) are connected with the other end of the seventh link (9) through the ninth rotation pair (503), and the other end of the eighth link (10) is rotated through the tenth The pair (16) is connected to the third hinged support (203) of the moving platform (2), and the rotation axes of the eighth rotation pair (502), the ninth rotation pair (503) and the tenth rotation pair (16) are mutually parallel.
The fully decoupled compound drive parallel mechanism with four degrees of freedom according to claim 1, wherein the base (1) is a circular plate-like structure.
The fully decoupled compound drive parallel mechanism with four degrees of freedom according to claim 1, characterized in that: the moving platform (2) is a square plate-like structure.
The fully decoupled compound drive parallel mechanism with four degrees of freedom according to claim 1, characterized in that: the first link (4) and the second link (5) are rod-shaped structures with both ends bent , and the bending directions at both ends are opposite.