CN111409059A - A four-degree-of-freedom parallel mechanism with closed-loop branches - Google Patents

Abstract

The invention relates to a four-degree-of-freedom parallel mechanism with a closed-loop branched chain, which comprises a main platform, a secondary platform and a fixed platform, wherein the main platform is connected with the secondary platform through a hinge; the secondary platform is connected with the main platform through a revolute pair; the secondary platform is connected with the fixed platform through a first driving branched chain and a third driving branched chain, and the main platform is connected with the fixed platform through a second driving branched chain and a fourth driving branched chain; the second driving branched chain and the fourth driving branched chain are linked to drive the main platform to turn back and forth; the first driving branched chain and the third driving branched chain are linked to drive the main platform to turn left and right; the first driving branched chain, the second driving branched chain, the third driving branched chain and the fourth driving branched chain can drive the main platform to move up and down or horizontally move left and right in a linkage manner. The mechanism has the characteristics of single direction and large rigidity, has high precision, can realize pose transformation of two rotations and two movements, can well solve the problems existing in the prior composite material tape laying, and meets the pose adjustment requirement in the tape laying process.

Description

A four-degree-of-freedom parallel mechanism with closed-loop branches

technical field

The invention relates to the field of robots, and belongs to a four-degree-of-freedom parallel mechanism with large rigidity.

Background technique

The aircraft shell requires the tape laying head to adjust the position and attitude accurately when wrapping the tape. At the same time, due to the heavy equipment of the tape laying head, the position and attitude adjustment device needs to have two characteristics of high rigidity and high precision. At the same time, the position and attitude adjustment range is not large, and the parallel mechanism It has the advantages of high stiffness, high precision and fast response, and is widely used in the fields of pose adjustment. For the design of the configuration of the parallel mechanism with few degrees of freedom, domestic and foreign scholars have carried out configuration synthesis of the four-degree-of-freedom mechanism through methods such as spiral theory, group theory, and mechanism topology. Not practical.

In response to the above problems, some scholars have adopted two new design methods. The first is the mechanism evolution method. Fan Caixia et al. used a plane 6R mechanism to introduce a U pair and add five constrained branches to obtain a 2T2R mechanism; the second is the form of adding constrained branches to a six-degree-of-freedom mechanism. The RPU branch was added to the mechanism as a passively constrained branch; Liu Jiankun replaced a six-degree-of-freedom branch with a CPU branch as an active branch; but after analysis and comparison, the stiffness and accuracy of the current four-degree-of-freedom parallel mechanism configuration are still Unable to meet the requirements for adjusting the position and attitude of the head of the aircraft shell.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a four-degree-of-freedom parallel mechanism with closed-loop branch chain, which has the characteristics of high rigidity and high precision, and realizes the position and attitude adjustment functions of two rotations and two movements of the main platform in space.

The technical solution of the present invention to solve the above problem is: a four-degree-of-freedom parallel mechanism with closed-loop branch chain, and its special features are:

Including main platform, secondary platform, fixed platform;

The secondary platform is located between the primary platform and the fixed platform, and the secondary platform and the primary platform are connected by a rotating pair;

The secondary platform and the fixed platform are connected by a first drive branch chain and a third drive branch chain, and the main platform and the fixed platform are connected by a second drive branch chain and a fourth drive branch chain;

The linkage of the second drive branch chain and the fourth drive branch chain can drive the main platform to turn back and forth;

The linkage of the first drive branch chain and the third drive branch chain can drive the main platform to turn left and right;

The linkage of the first driving branch chain, the second driving branch chain, the third driving branch chain and the fourth driving branch chain can drive the main platform to move up and down or horizontally and horizontally.

Further, the above-mentioned second drive branch chain and the fourth drive branch chain have the same structure;

The second drive branch chain includes a first rod, a second rod, a third rod, and a fourth rod, wherein the first rod and the second rod constitute a first moving pair;

The first moving pair, the third rod, and the fourth rod are connected end to end to form a triangular closed structure, wherein the two ends of the third rod are hinged with one end of the second rod and the fourth rod respectively, and the fourth rod is hinged. The other end of the rod and the end of the first rod are compound hinged with the secondary platform.

Further, the middle part of the third rod is hinged with the fixed platform.

Further, one end of the above-mentioned second drive branch chain and the fourth drive branch chain are respectively connected with the active platform through the Hook hinge, and the other ends of the second drive branch chain and the fourth drive branch chain are respectively connected with the fixed platform through the Hook hinge. .

Further, the structures of the above-mentioned second driving branch chain and the fourth driving branch chain are the same;

The second drive branch chain includes a fifth rod and a sixth rod. The fifth rod and the sixth rod are combined to form a second moving pair, and the upper end of the fifth rod and the lower end of the sixth rod are respectively With fork hinge seat and cross shaft.

Further, the above-mentioned main platform is a flat plate.

Further, the above-mentioned secondary platform is a rod, and both ends of the rod are provided with fork-shaped hinge seats.

Further, the above-mentioned fixed platform is a plate.

Further, the hinge point of the second drive branch and the fourth drive branch and the main platform, the first drive branch and the third drive branch and the hinge point of the secondary platform are on the same plane, and the four hinge points form a rhombus.

Further, the hinge points of the second drive branch and the fourth drive branch and the fixed platform, the first drive branch and the third drive branch and the hinge point of the fixed platform are located on the same plane, and the four hinge points form a rhombus.

Advantages of the present invention:

The two symmetrical branch chains of the present invention adopt a triangular closed-loop structure, and their structural stability and rigidity are improved compared with the traditional mechanism. At the same time, the drive pair is also selected due to the reduction of the force on the branch chain, so that the power is smaller and the precision is higher. High drive motor.

Description of drawings

Fig. 1 is the overall structure diagram of the four-degree-of-freedom parallel mechanism containing closed-loop branch chain of the present invention;

Fig. 2 is the connection diagram of the first drive branch chain and the third drive branch chain and the sub-platform of the present invention;

Fig. 3 is the first drive branch chain structure diagram of the present invention;

FIG. 4 is a structural diagram of the second drive branch chain of the present invention.

Among them: 1. main platform; 2. secondary platform; 3. fixed platform; 4. first drive branch; 5, second drive branch; 51, fifth rod; 52, sixth rod; 53, fork 54, and the cross shaft; 6, the third drive branch; 61, the first rod; 62, the second rod; 63, the third rod; 64, the fourth rod; 65, the through hole 7. The fourth drive branch.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Accordingly, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention.

Referring to FIG. 1, a four-degree-of-freedom parallel mechanism with a closed-loop branch chain includes a main platform 1, a secondary platform 2, and a fixed platform 3; the secondary platform 2 is located between the main platform 1 and the fixed platform 3, and the secondary platform 2 and The main platform 1 is connected by a rotating pair. The secondary platform 2 and the fixed platform 3 are connected by the first driving branch 4 and the third driving branch 6, and the main platform 1 and the fixed platform 3 are connected by the second driving branch 5 and the fourth driving branch. Chain 7 is connected.

The linkage of the second drive branch chain 5 and the fourth drive branch chain 7 can drive the main platform 1 to turn forward and backward; the linkage of the first drive branch 4 and the third drive branch 6 can drive the main platform 1 to turn left and right; the first drive branch The linkage of the chain 4 , the second driving branch 5 , the third driving branch 6 and the fourth driving branch 7 can drive the main platform 1 to move up and down or horizontally and horizontally.

The main platform 1 is a flat plate. The secondary platform 2 is a rod, and two ends of the rod are provided with fork-shaped hinge seats 53 . The fixed platform 3 is a plate.

As a preferred embodiment of the present invention, referring to FIG. 2 and FIG. 3 , the first driving branch 4 and the third driving branch 6 have the same structure. The third drive branch 6 includes a first rod 61, a second rod 62, a third rod 63, and a fourth rod 64, wherein the first rod 61 and the second rod 62 constitute a first moving pair , can be telescopic; the first moving pair, the third rod 63 and the fourth rod 64 are connected end to end to form a triangular closed structure, wherein the two ends of the third rod 63 are connected to the second rod 62 and the fourth rod respectively. One end of the rod member 64 is hinged, and the other end of the fourth rod member 64 and the end of the first rod member 61 are compound hinged with the secondary platform 2 .

As a preferred embodiment of the present invention, referring to FIG. 3 , a through hole 65 is provided in the middle of the third rod member 63 , and is hinged with the fixed platform 3 through the through hole 65 .

As a preferred embodiment of the present invention, referring to FIG. 1 and FIG. 4 , the structures of the second drive branch 5 and the fourth drive branch 7 are the same. One ends of the second driving branch 5 and the fourth driving branch 7 are respectively connected to the main platform 1 through the Hooke hinge, and the other ends of the second driving branch 5 and the fourth driving branch 7 are respectively connected to the fixed platform through the Hooke hinge 3 connections.

The second drive branch 5 includes a fifth rod 51 and a sixth rod 52. The fifth rod 51 and the sixth rod 52 are combined to form a second moving pair, which can be extended and retracted. The fifth rod 51 The upper end and the lower end of the sixth rod 52 are respectively provided with a fork hinge seat 53 and a cross shaft 54 .

In the present invention, the second drive branch 5 and the fourth drive branch 7 are located at the same hinge point with the main platform 1 , the first drive branch 4 and the third drive branch 6 and the secondary platform 2 . Plane, four hinge points form a rhombus. The hinge point of the second drive branch 5 and the fourth drive branch 7 and the fixed platform 3, the first drive branch 4 and the third drive branch 6 and the hinge point of the fixed platform 3 are located on the same plane, and the four hinge The dots form a rhombus.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Those skilled in the art can still adjust the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. . Therefore, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims (10)

1. a four-degree-of-freedom parallel mechanism containing a closed-loop branched chain is characterized in that: Including the main platform (1), the secondary platform (2), and the fixed platform (3); The secondary platform (2) is located between the primary platform (1) and the fixed platform (3), and the secondary platform (2) is connected with the primary platform (1) through a rotating pair; The secondary platform (2) and the fixed platform (3) are connected by a first drive branch (4) and a third drive branch (6), and the main platform (1) and the fixed platform (3) are connected Connected by the second drive branch (5) and the fourth drive branch (7); The linkage of the second drive branch chain (5) and the fourth drive branch chain (7) can drive the main platform (1) to turn back and forth; The linkage of the first drive branch chain (4) and the third drive branch chain (6) can drive the main platform (1) to turn left and right; The linkage of the first drive branch (4), the second drive branch (5), the third drive branch (6) and the fourth drive branch (7) can drive the main platform (1) to move up and down or left and right in the horizontal direction Pan. 2. a kind of four-degree-of-freedom parallel mechanism containing closed-loop branched chain according to claim 1, is characterized in that: The first driving branch (4) and the third driving branch (6) have the same structure; The third drive branch (6) includes a first rod (61), a second rod (62), a third rod (63), and a fourth rod (64), wherein the first rod (61) ), the second rod (62) constitutes the first moving pair; The first moving pair, the third rod (63), and the fourth rod (64) are connected end to end to form a triangular closed structure, wherein the two ends of the third rod (63) are respectively connected to the second rod (62) , One end of the fourth rod (64) is hinged, and the other end of the fourth rod (64) and the end of the first rod (61) are compound hinged with the secondary platform (2). 3. a kind of four-degree-of-freedom parallel mechanism containing closed-loop branched chain according to claim 2, is characterized in that: The middle part of the third rod (63) is hinged with the fixed platform (3). 4. a kind of four-degree-of-freedom parallel mechanism containing closed-loop branched chain according to any one of claims 1-3, is characterized in that: One ends of the second driving branch (5) and the fourth driving branch (7) are respectively connected to the main platform (1) through Hooke hinges, and the second driving branch (5) and the fourth driving branch (7) The other ends are respectively connected with the fixed platform (3) through Hook hinges. 5. a kind of four-degree-of-freedom parallel mechanism containing closed-loop branched chain according to claim 4, is characterized in that: The structures of the second drive branch (5) and the fourth drive branch (7) are the same; The second drive branch (5) includes a fifth rod (51) and a sixth rod (52), and the fifth rod (51) and the sixth rod (52) are combined to form a second moving pair , the upper end of the fifth rod (51) and the lower end of the sixth rod (52) are respectively provided with a fork hinge seat and a cross shaft (54). 6. a kind of four-degree-of-freedom parallel mechanism containing closed-loop branched chain according to claim 1, is characterized in that: The main platform (1) is a flat plate. 7. a kind of four-degree-of-freedom parallel mechanism containing closed-loop branched chain according to claim 1, is characterized in that: The secondary platform (2) is a rod, and both ends of the rod are provided with fork-shaped hinge seats. 8. a kind of four-degree-of-freedom parallel mechanism containing closed-loop branched chain according to claim 1, is characterized in that: The fixed platform (3) is a plate. 9. a kind of four-degree-of-freedom parallel mechanism containing closed-loop branched chain according to claim 5, is characterized in that: The hinge points of the second drive branch (5) and the fourth drive branch (7) and the main platform (1), the first drive branch (4) and the third drive branch (6) and the secondary platform ( 2) The hinge points are in the same plane, and the four hinge points form a rhombus. 10. A kind of four-degree-of-freedom parallel mechanism containing closed-loop branched chain according to claim 5, is characterized in that: The hinge point between the second drive branch (5) and the fourth drive branch (7) and the fixed platform (3), the first drive branch (4) and the third drive branch (6) and the fixed platform ( 3) The hinge points are in the same plane, and the four hinge points form a rhombus.

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