CN105234924B - Four-degree-of-freedom parallel mechanism - Google Patents

Abstract

The invention discloses a four-degree-of-freedom parallel mechanism, which includes a fixed frame, a moving platform, and four branch chains with the same structure arranged between the fixed frame and the moving platform; the branch chains include a main arm, a connecting shaft, two A parallel and equal-length driven arm and four T-shaped shafts, the active arm is rotatably connected with the fixed frame, one end of the driven arm is connected with the active arm through two T-shaped shafts, and the other end is connected through two T-shaped shafts The shape shaft is connected with the connection shaft, and the connection shaft is rotatably connected with the moving platform. The parallel mechanism moving platform adopts a single platform structure, which can reduce the mass of moving parts, and is beneficial to realize the dynamic response characteristics of high speed and high acceleration.

Description

A Four Degrees of Freedom Parallel Mechanism

technical field

The invention relates to a parallel mechanism, in particular to a four-degree-of-freedom parallel mechanism with three-dimensional translation and one-dimensional rotation in space.

Background technique

The three-dimensional translation and one-dimensional rotation four-degree-of-freedom parallel mechanism has been widely used in the high-speed and light-load handling operations of automated production lines in the fields of food, medicine, modern logistics, and electronic information because it can meet operations such as the handling of space objects.

The US patent No. US20090019960A1 discloses a high-speed parallel robot with four degrees of freedom, and the European patent No. EP1084802B1 discloses a four-degree-of-freedom parallel robot. Through the analysis of these two patents, it can be known that the existing A parallel mechanism that realizes three-dimensional translation and one-dimensional rotation includes four active branch chains and a moving platform, and each branch chain includes two parts: a near frame bar and a far frame bar. One end of the proximal rod has only one degree of freedom of movement or rotation relative to the fixed frame, and the other end is connected to one end of the far rod through a hinge with only two degrees of freedom; the other end of the far rod has only two degrees of freedom. The hinge of the degree of freedom is connected with the moving platform to ensure the translational movement of the mechanism; the moving platform is composed of four parts, two of which must be parallel to each other, and the other two parts are connected to the aforementioned two parallel parts through rotating hinges. The mutual rotation between the parts can realize the degree of freedom of rotation around the axis perpendicular to the moving platform, and at the same time, the range of the rotation angle can be enlarged by matching the corresponding amplification mechanism.

However, the limitation of the above-mentioned mechanism is that the structure of the moving platform is complicated, and the weight of the moving platform is relatively large, which is not conducive to improving the dynamic response characteristics of the mechanism.

Contents of the invention

The purpose of the present invention is to provide a four-degree-of-freedom parallel mechanism with three-dimensional translation and one-dimensional rotation using a single-motion platform.

The technical solution to realize the object of the present invention is: a four-degree-of-freedom parallel mechanism, including a fixed frame, a moving platform, and a first branch chain, a second branch chain, a third branch chain and the fourth branch,

The first branch chain, the second branch chain, the third branch chain and the fourth branch chain have the same structure; each branch chain includes a driving device fixed on a fixed frame, a driving arm, a first driven arm, a second Two driven arms and connecting shafts, one end of the active arm is rotatably connected to the fixed frame, and fixedly connected to the driving end of the driving device, the two sides of the other end of the active arm are respectively connected to the first driven arm, One end of the second driven arm is connected, the other end of the first driven arm and the second driven arm are connected with the connecting shaft, the connecting shaft is connected with the moving platform in rotation, and the first driven arm is connected with the second driven arm. The follower arms are parallel and equal in length;

The four rotation axes connecting the fixed frame and the active arm in the first branch chain, the second branch chain, the third branch chain and the fourth branch chain are parallel to each other.

Compared with the prior art, the present invention has the following remarkable advantages: the four-degree-of-freedom parallel mechanism of the present invention has a simple and compact structure, and a clear movement mode; since the moving platform adopts a single-platform structure, the quality of the moving platform is greatly reduced, It is beneficial to improve the dynamic response characteristics of the mechanism and to realize high speed and high acceleration.

Description of drawings

Fig. 1 is a schematic structural diagram of Embodiment 1 of the present invention.

Fig. 2 is a schematic diagram of the structure of the branched chain in Example 1 of the present invention.

Fig. 3 is a structural schematic diagram of the connecting shaft and the moving platform of the present invention.

Fig. 4 is a schematic diagram of the structure of the T-shaped shaft of the present invention.

Fig. 5 is a schematic structural diagram of Embodiment 2 of the present invention.

Fig. 6 is a schematic diagram of the structure of the branched chain in Example 2 of the present invention.

Fig. 7 is a schematic structural view of the ball joint of the present invention.

The meanings represented by the numbers in the figure are: 1. Fixed frame, 2. Moving platform, 3. Suction cup, 11. Driving device, 12. Active arm, 13. First T-shaped shaft, 14. Second T-shaped shaft, 15 , the first driven arm, 16, the second driven arm, 17, the third T-shaped shaft, 18, the fourth T-shaped shaft, 19, the connecting shaft, 20, the connecting piece, 131, the first ball joint, 141, The second ball joint, 171, the third ball joint, 181, the fourth ball joint, a, the first axis, b, the second axis.

detailed description

In conjunction with the accompanying drawings, a four-degree-of-freedom parallel mechanism of the present invention includes a fixed frame 1, a moving platform 2, and a first branch chain, a second branch chain, and a third branch chain arranged between the fixed frame 1 and the moving platform 2 And the fourth branch chain, the first branch chain, the second branch chain, the third branch chain and the fourth branch chain structure are the same; each branch chain all includes the driving device 11 fixedly arranged on the fixed frame 1, the active arm 12. The first driven arm 15, the second driven arm 16 and the connecting shaft 19. One end of the active arm 12 is connected to the fixed frame 1 in rotation, and is fixedly connected to the driving end of the driving device 11. The active Both sides of the other end of the arm 12 are connected with one end of the first driven arm 15 and the second driven arm 16 respectively, and the other ends of the first driven arm 15 and the second driven arm 16 are connected with the connecting shaft 19 , the connecting shaft 19 is rotationally connected with the moving platform 2, and the first driven arm 15 and the second driven arm 16 are parallel and equal in length;

The four rotation axes connecting the fixed frame 1 and the active arm 12 in the first branch chain, the second branch chain, the third branch chain and the fourth branch chain are parallel to each other.

The main arm 12 is connected to the first driven arm 15 through a first T-shaped shaft 13, and the main arm 12 is connected to the second driven arm 16 through a second T-shaped shaft 14. The first driven arm 15 It is connected with the connecting shaft 19 through the third T-shaped shaft 17 , and the second driven arm 16 is connected with the connecting shaft 19 through the fourth T-shaped shaft 18 .

The active arm 12 is rotationally connected to the first T-shaped shaft 13, the active arm 12 is rotationally connected to the second T-shaped shaft 14, and the first T-shaped shaft 13 is rotationally connected to the first driven arm 15. The second T-shaped shaft 14 is rotationally connected with the second driven arm 16; the first driven arm 15 is rotationally connected with the third T-shaped shaft 17, and the third T-shaped shaft 17 is rotationally connected with the connecting shaft 19 , the second driven arm 16 is rotationally connected to the fourth T-shaped shaft 18, and the fourth T-shaped shaft 18 is rotationally connected to the connecting shaft 19;

The axis of rotation connecting the first T-shaped shaft 13 and the driving arm 12 is perpendicular to the axis of rotation connecting the first T-shaped shaft 13 and the first driven arm 15; connecting the second T-shaped shaft 14 and the driving arm the axis of rotation of the arm 12 perpendicularly intersects the axis of rotation connecting said second T-shaped shaft 14 and the second driven arm 16;

The rotation axis connecting the third T-shaped shaft 17 and the connecting shaft 19 is perpendicular to the rotation axis connecting the third T-shaped shaft 17 and the first driven arm 15; connecting the fourth T-shaped shaft 18 and connecting The axis of rotation of the shaft 19 is perpendicular to the axis of rotation connecting the fourth T-shaped shaft 18 and the second driven arm 16;

The rotation axis connecting the first T-shaped shaft 13 and the active arm 12 is collinear with the rotation axis connecting the second T-shaped shaft 14 and the active arm 12 on the first axis a, and the third T-shaped shaft 17 is connected The axis of rotation of the connecting shaft 19 and the axis of rotation connecting the fourth T-shaped shaft 18 and the connecting shaft 19 are collinear on the second axis b, the first axis a, the second axis b, and the active arm are connected 12 and the axis of rotation of the fixed mount 1 are parallel to each other;

The rotation axis connecting the first T-shaped shaft 13 and the first driven arm 15, the rotation axis connecting the second T-shaped shaft 14 and the second driven arm 16, and the third T-shaped shaft 17 and the first driven arm 15 The rotation axis of the T-shaped shaft 18 and the rotation axis connecting the fourth T-shaped shaft 18 and the second driven arm 16 are four axes parallel to each other.

Alternatively, the active arm 12 is connected to the first driven arm 15 through a first ball joint 131, the active arm 12 and the second driven arm 16 are connected through a second ball joint 141, and the first driven arm 15 It is connected with the connecting shaft 19 through the third ball joint 171 , and the second driven arm 16 is connected with the connecting shaft 19 through the fourth ball joint 181 .

A connecting rod 20 is arranged between the first driven arm 15 and the second driven arm 16, and one end of the connecting rod 20 is rotatably connected with the first driven arm 15, and the other end is rotatably connected with the second driven arm 16. The axis of the center of rotation of the connecting rod 20 and the first driven arm 15 and the center of rotation of the connecting rod 20 and the second driven arm 16 is parallel to the axis of rotation connecting the active arm 12 and the fixed mount 1 .

Both the first ball joint 131 and the second ball joint 141 are fixedly connected to the active arm 12; the third ball joint 171 and the fourth ball joint 181 are both fixedly connected to the connecting shaft 19; the first driven arm 15 One end of the second follower arm 16 is ball hinged with the first ball joint 131, and the other end is ball hinged with the third ball joint 171; one end of the second follower arm 16 is ball hinged with the second ball joint 141, and the other end is ball hinged with the fourth ball joint 181. Articulation;

The axis passing through the center of the first ball joint 131 and the center of the second ball joint 141, the axis passing through the center of the third ball joint 171 and the center of the fourth ball joint 181, and connecting the active arm 12 with the fixed frame 1's axes of rotation are parallel to each other.

In order to further understand the invention content, characteristics and effects of the present invention, the following examples are given, and detailed descriptions are as follows in conjunction with the accompanying drawings:

Example 1:

1 to 4, a four-degree-of-freedom parallel mechanism includes a fixed frame 1, a moving platform 2, and a first branch chain, a second branch chain, and a third branch arranged between the fixed frame 1 and the moving platform 2. chain and the fourth branch chain, the first branch chain, the second branch chain, the third branch chain and the fourth branch chain have the same structure; Arm 12, first T-shaped shaft 13, second T-shaped shaft 14, first driven arm 15, second driven arm 16, third T-shaped shaft 17, fourth T-shaped shaft 18 and connecting shaft 19; One end of the active arm 12 is rotatably connected with the fixed frame 1, and is fixedly connected with the driving end of the driving device 11. One end of the shaft 14 is rotationally connected, the other end of the first T-shaped shaft 13 is rotationally connected with one end of the first driven arm 15, and the other end of the first driven arm 15 is connected with one end of the third T-shaped shaft 17 Rotationally connected, the other end of the third T-shaped shaft 17 is rotatably connected with the connecting shaft 19, the other end of the second T-shaped shaft 14 is rotatably connected with one end of the second follower arm 16, and the second follower The other end of the boom 16 is rotatably connected to one end of the fourth T-shaft 18 , and the other end of the fourth T-shaft 18 is rotatably connected to a connecting shaft 19 , and the connecting shaft 19 is rotatably connected to the moving platform 2 . The first driven arm 15 and the second driven arm 16 are parallel and equal in length. A suction cup 3 is fixedly connected to the end of the moving platform 2 .

The axis of rotation connecting the first T-shaped shaft 13 and the driving arm 12 is perpendicular to the axis of rotation connecting the first T-shaped shaft 13 and the first driven arm 15; connecting the second T-shaped shaft 14 and the driving arm The axis of rotation of the arm 12 is perpendicular to the axis of rotation connecting the second T-shaped shaft 14 and the second driven arm 16; The axis of rotation of the T-shaped shaft 17 and the first driven arm 15 intersects vertically; The axes of rotation intersect perpendicularly.

The rotation axis connecting the first T-shaped shaft 13 and the active arm 12 is collinear with the rotation axis connecting the second T-shaped shaft 14 and the active arm 12 on the first axis a, and the third T-shaped shaft 17 is connected The axis of rotation of the connecting shaft 19 and the axis of rotation connecting the fourth T-shaped shaft 18 and the connecting shaft 19 are collinear on the second axis b, the first axis a, the second axis b, and the active arm are connected 12 and the axis of rotation of the fixed mount 1 are parallel to each other.

The rotation axis connecting the first T-shaped shaft 13 and the first driven arm 15, the rotation axis connecting the second T-shaped shaft 14 and the second driven arm 16, and the third T-shaped shaft 17 and the first driven arm 15 The rotation axis of the T-shaped shaft 18 and the rotation axis connecting the fourth T-shaped shaft 18 and the second driven arm 16 are four axes parallel to each other.

The four rotation axes connecting the fixed frame 1 and the active arm 12 in the first branch chain, the second branch chain, the third branch chain and the fourth branch chain are parallel to each other.

Example 2:

5~7 and 3, a four-degree-of-freedom parallel mechanism includes a fixed frame 1, a moving platform 2, and a first branch chain, a second branch chain, and a first branch chain arranged between the fixed frame 1 and the moving platform 2. Three branch chains and the fourth branch chain, the first branch chain, the second branch chain, the third branch chain and the fourth branch chain have the same structure; each branch chain includes a drive device 11 fixedly arranged on the fixed frame 1 , the master arm 12 , the first ball joint 13 , the second ball joint 14 , the first follower arm 15 , the second follower arm 16 , the third ball joint 17 , the fourth ball joint 18 and the connecting shaft 19 . One end of the active arm 12 is rotatably connected to the fixed frame 1, and fixedly connected to the driving end of the driving device 11, and the two sides of the other end of the active arm 12 are respectively connected to the first ball joint 13 and the second ball joint. 14 fixed connection; one end of the first driven arm 15 is ball-hinged with the first ball joint 13, and the other end is ball-hinged with the third ball joint 17; one end of the second driven arm 16 is connected with the second ball joint 14 The other end is ball hinged with the fourth ball joint 18; the third ball joint 17 and the fourth ball joint 18 are fixedly connected with the connecting shaft 19, and the connecting shaft 18 is connected with the moving platform 2 in rotation. The first driven arm 15 and the second driven arm 16 are parallel and equal in length, a connecting rod 20 is arranged between the first driven arm 15 and the second driven arm 16, and one end of the connecting rod 20 is connected to The first follower arm 15 is rotatably connected, and the other end is rotatably connected with the second follower arm 16 . A suction cup 3 is fixedly connected to the end of the moving platform 2 .

The axis that passes through the two centers of the center of the first ball joint 13 and the center of the second ball joint 14 passes through the two centers of the center of the third ball joint 17 and the center of the fourth ball joint 18 The axis of the center of the sphere, the axis of the two centers of the center of rotation of the connecting rod 20 and the first driven arm 15 and the center of rotation of the connecting rod 20 and the second driven arm 16, and the connecting rod 12 The axis of rotation of the fixed frame 1 is parallel to each other.

The four rotation axes connecting the fixed frame 1 and the active arm 12 in the first branch chain, the second branch chain, the third branch chain and the fourth branch chain are parallel to each other.

It can be seen from the above that each branch chain of the present invention adopts a rotating fork to be rotatably connected to the fixed frame, and the four rotating axes are parallel to each other, so that the rotation of the moving platform at the end can be realized, and the use of a motion conversion mechanism on the moving platform is avoided. The quality of the moving platform is greatly reduced, which is beneficial to improving the speed and acceleration of the mechanism, thereby improving production efficiency.

Claims (1)

1. a kind of four-freedom parallel mechanism, including fixed mount (1), moving platform (2) and fixed mount (1) and moving platform are arranged in (2) the first side chain, the second side chain, the 3rd side chain and the 4th side chain between, it is characterised in that first side chain, second Chain, the 3rd side chain and the 4th branched structure are identical；Every side chain includes the drive device being fixedly installed on fixed mount (1) (11), master arm (12), the first slave arm (15), the second slave arm (16) and connecting shaft (19), the one of the master arm (12) End rotates with fixed mount (1) and is connected, and, the other end of the master arm (12) affixed with the drive end of the drive device (11) One end respectively with the first slave arm (15), the second slave arm (16) of both sides be connected, first slave arm (15), second from The other end of swing arm (16) is connected with connecting shaft (19), and the connecting shaft (19) and moving platform (2) are rotated and be connected, described first from Swing arm (15) is parallel and isometric with the second slave arm (16)；

Connect master arm (12) in the fixed mount (1) and the first side chain, the second side chain, the 3rd side chain and the 4th side chain Four pivot center is parallel to each other；

It is connected by the first T-shaped axle (13) between the master arm (12) and the first slave arm (15), master arm (12) and second Connected by the second T-shaped axle (14) between slave arm (16), the 3rd T-shaped is passed through between the first slave arm (15) and connecting shaft (19) Axle (17) is connected, and is connected by the 4th T-shaped axle (18) between the second slave arm (16) and connecting shaft (19), the master arm (12) Rotated between the first T-shaped axle (13) and be connected, rotated between master arm (12) and the second T-shaped axle (14) and be connected, the first T-shaped axle (13) rotated between the first slave arm (15) and be connected, rotated between the second T-shaped axle (14) and the second slave arm (16) and be connected；The Rotated between one slave arm (15) and the 3rd T-shaped axle (17) and be connected, the company of rotation between the 3rd T-shaped axle (17) and connecting shaft (19) Connect, rotated between the second slave arm (16) and the 4th T-shaped axle (18) and be connected, turn between the 4th T-shaped axle (18) and connecting shaft (19) Dynamic connection；

Connect the pivot center of the first T-shaped axle (13) and master arm (12) and be connected the first T-shaped axle (13) and first The pivot center of slave arm (15) intersects vertically；Connect pivot center and the company of the second T-shaped axle (14) and master arm (12) The pivot center for connecing the second T-shaped axle (14) and the second slave arm (16) intersects vertically；

Connect the pivot center of the 3rd T-shaped axle (17) and connecting shaft (19) and be connected the 3rd T-shaped axle (17) and first The pivot center of slave arm (15) intersects vertically；Connect pivot center and the company of the 4th T-shaped axle (18) and connecting shaft (19) The pivot center for connecing the 4th T-shaped axle (18) and the second slave arm (16) intersects vertically；

Connect the pivot center of the first T-shaped axle (13) and master arm (12) and be connected the second T-shaped axle (14) and actively The pivot center of arm (12) is collinear in first axle (a), connects the pivot center of the 3rd T-shaped axle (17) and connecting shaft (19) Second axis (b), the first axle are collinear in the pivot center for being connected the 4th T-shaped axle (18) and connecting shaft (19) A the pivot center of (), second axis (b) and the connection master arm (12) and fixed mount (1) is parallel to each other；

Connect pivot center, connection the second T-shaped axle (14) and second slave arm of the first T-shaped axle (13) and the first slave arm (15) (16) pivot center, the pivot center of the 3rd T-shaped axle (17) of connection and the first slave arm (15), the 4th T-shaped axle (18) of connection Totally four axis are parallel to each other with the pivot center of the second slave arm (16)；

Or be connected by the first spherojoint (131) between the master arm (12) and the first slave arm (15), master arm (12) It is connected by the second spherojoint (141) between the second slave arm (16), is led between the first slave arm (15) and connecting shaft (19) The connection of the 3rd spherojoint (171) is crossed, is connected by the 4th spherojoint (181) between the second slave arm (16) and connecting shaft (19), Connecting rod (20), described connecting rod (20) one end and first are provided between first slave arm (15) and the second slave arm (16) Slave arm (15) rotates connection, and the other end is rotated with the second slave arm (16) and is connected；Cross connecting rod (20) and the first slave arm (15) axis of center of rotation and connecting rod (20) and the center of rotation of the second slave arm (16), with connection master arm (12) with The pivot center of fixed mount (1) is parallel to each other；

First spherojoint (131) and the second spherojoint (141) are affixed with master arm (12)；3rd spherojoint And the 4th spherojoint (181) is affixed with connecting shaft (19) (171)；One end of first slave arm (15) and the first spherojoint (131) ball-joint, the other end and the 3rd spherojoint (171) ball-joint；One end of second slave arm (16) connects with the second ball Head (141) ball-joint, the other end and the 4th spherojoint (181) ball-joint；

Cross the first spherojoint (131) centre of sphere and the axis of the second spherojoint (141) centre of sphere, the 3rd spherojoint (171) ball excessively The axis and the connection master arm (12) of the heart and the 4th spherojoint (181) centre of sphere are mutual with the pivot center of fixed mount (1) It is parallel.