CN102514004A - Translational high-speed parallel mechanism with four branched chains and two degrees of freedom - Google Patents

Abstract

The invention discloses a four-branch two-degree-of-freedom translation high-speed parallel mechanism, which comprises a fixed frame, a moving platform and two branch chain groups with the same structure. Two driving devices are fixedly connected to the fixed frame; the branch chain groups are symmetrically arranged between the fixed frame and the moving platform; each branch chain group is composed of two branch chains with the same structure, each The first branch chain includes a near frame rod and two far frame rods with the same structure and arranged in parallel. One end of the near frame rod is fixedly connected to the driving device, the other end is fixedly connected to the upper connecting shaft of the respective branch chains, and the lower connecting shaft is connected to the moving platform. Fixed connection, the two ends of the far frame rod are respectively hinged with the upper and lower connecting shaft balls to form a parallelogram structure; the ends of the near frame rods of the two branch chains are each fixedly connected to a rotating shaft, and the shaft ends of the rotating shaft are provided with two shafts with the same structure. A pair of bevel gears meshing with each other. The invention has reasonable and compact structure design, good rigidity and stability; each branch chain is symmetrically arranged, the force is uniform, and the service life is high.

Description

Four-branched two-degree-of-freedom translational high-speed parallel mechanism

technical field

The invention relates to a robot, in particular to a robot parallel mechanism with two-dimensional translation in space.

Background technique

The authorized announcement number is US7090458B2, and the US patent issued on August 15, 2006 discloses a parallel mechanism that can realize two-degree-of-freedom translation, including a frame, a moving platform, and two pairs of branch chains; Two servo motors are installed, and the moving platform is connected to the frame through two branches to form a parallel closed-loop structure; each of the two branch chains contains two parallelogram mechanisms, which are respectively used as a driving rod group and a driven rod group, and the movement between each part It is completely connected by rotating hinges; the parallelogram branch chain structure is used to realize the two-dimensional translation of the moving platform. The limitations of the above mechanism are: each branch chain of the mechanism contains two sets of parallelogram mechanisms, the structure is complex; all moving components are in the same plane or parallel to the plane, and the stiffness in the normal direction of the plane is relatively poor.

Contents of the invention

In view of the above prior art, the present invention provides a parallel mechanism with two translational degrees of freedom, which has good structural rigidity, long service life and simple structure.

In order to solve the above-mentioned technical problems, the technical scheme realized by the four-branch two-degree-of-freedom translational high-speed parallel mechanism of the present invention is: the mechanism includes a fixed frame, a moving platform and two branch chain groups, and the two branch chain groups have the same structure , and are symmetrically arranged between the fixed frame and the moving platform; two driving devices are fixedly connected to the fixed frame; each branch chain group is composed of branch chain a and branch chain b with the same structure, and the branch chain Both the chain a and the bracket b include a near frame rod and two parallel and equal-length far frame rods. The two ends of the two far frame rods are respectively connected with an upper connecting shaft and a lower connecting shaft. It is hinged with the upper connecting shaft ball, and the other end is respectively hinged with the lower connecting shaft ball on the moving platform. The lower connecting shaft, the upper connecting shaft and the two parallel far The frame bar forms a parallelogram structure; one end of the branch chain a and the branch chain b near the frame bar is respectively fixed with a rotating shaft, one of the rotating shafts is connected with the driving device, and two shaft ends of the two rotating shafts are provided with two shafts with the same structure. A pair of bevel gears meshing with each other, the other ends of the two near-frame rods are fixedly connected to the upper connecting shafts in their respective branch chains; the axes of the two bevel gears coincide with the axes of the two rotating shafts and meet at one point .

The four-branched two-degree-of-freedom translational high-speed parallel mechanism of the present invention, wherein the branched chain a and the branched chain b are driven by the meshing transmission of the pair of bevel gears, so that the driving device drives the branched chain a and the branched chain b When one of the branch chains in the branch chain b, the other branch chain performs the same movement, and the parallelogram structure formed by the lower connecting shaft, the upper connecting shaft and two parallel far-supporting rods of each branch chain jointly supports the described The constraint effect of the moving platform, so that the moving platform can perform two-dimensional translation in the symmetrical plane of the two branch chains.

Compared with prior art, the beneficial effect of the present invention is:

Since the two groups of branch chains in the present invention are symmetrically arranged and the structure of each branch chain in the branch chain group is simple, the reliability of the mechanism is improved, the service life is prolonged, and the manufacturing cost is low; in addition, because each The branch chains are arranged at angles to each other, which strengthens the constraint on the degree of freedom of the moving platform, and greatly improves the lateral stiffness of the mechanism; in addition, the ball joint method is adopted in the parallelogram structure of each branch chain, eliminating The gap is convenient, so the positioning accuracy of the mechanism is high; the structure of the branch chain of the mechanism is simple, the form of the moving platform is simple, the overall weight is light, and it is easy to realize high-speed movement, which can meet the needs of fast pick-and-place.

Description of drawings

Fig. 1 is a three-dimensional structural schematic diagram of a four-branched two-degree-of-freedom translational high-speed parallel mechanism of the present invention;

Fig. 2 is a schematic diagram of the connecting structure of the proximal rod in the present invention shown in Fig. 1 .

In the picture:

1-Drive device 2-Fixer frame 3a, 3b-near frame rod 4a, 4b-upper connecting shaft

5a, 5b remote frame rod 6a, 6b-lower connecting shaft 7-moving platform 8a, 8b-rotating shaft

9a, 9b bevel gears.

Detailed ways

The present invention will be further described in detail below in combination with specific embodiments.

As shown in Figure 1, the four-branched two-translational high-speed parallel mechanism of the present invention includes a fixed frame 2, a moving platform 7, and two structurally identical Branch chain group. Each branch chain group is composed of two branch chains a and branch b with the same structure. The drive device 1 is fixedly connected to the fixed frame 2. For the convenience of comparing the drawings, take the right front side branch chain in Fig. 1 as an example Describe the composition of each branch chain. One end of the near frame rod 3a is affixed to the output end of the drive device 1 fixed on the fixed frame 2, and the other end of the near frame rod 3a is affixed to the upper connecting shaft 4a. One end of the far frame rod 5a is ball-hinged with the upper connecting shaft 4a through a ball hinge respectively, and the other end is also ball-hinged with the lower connecting shaft 6a fixed on the moving platform 7 through a ball hinge respectively. The lower connecting shaft 6a (6b), the upper connecting shaft 4a (4b) and the two parallel far frame rods 5a (5b) form a parallelogram structure, and the driving device 1 is a near The frame bar 3a provides a rotational degree of freedom. A rotating shaft 8a is fixedly connected to the near frame rod 3a.

As shown in Figure 1, one end of two branch chains, that is, branch chain a and branch chain b near the frame bars 3a, 3b, is respectively fixed with a rotating shaft 8a, 8b, wherein one rotating shaft is connected with the driving device 1, and the two rotating shafts 8a, 8b The shaft end of 8b is provided with two pairs of bevel gears 9a, 9b that are meshed with each other with the same structure, and the other ends of the two near frame rods 3a, 3b are affixed to the upper connecting shafts 4a, 4b in their respective branch chains; The axes of the two bevel gears 9a, 9b respectively coincide with the axes of the two rotating shafts 8a, 8b and meet at one point.

The branch chain a and the branch chain b are driven through the engagement of the pair of bevel gears 9a, 9b, so that when the drive device 1 drives any branch chain in the branch chain a and the branch chain b, another A branch chain will produce the same motion; The parallelogram structure that is formed by two groups of described far-end frame rods 5a (5b) and described upper and lower connecting shafts 4a (4b) and 6a (6b) is common to the constraint of described moving platform 7 As a result, the moving platform 7 is limited to two-dimensional translation only in the plane of symmetry of the branch chain a and branch chain b.

The characteristics of the high-speed parallel mechanism with four branch chains and two translation degrees of freedom of the present invention are:

(1) Through the four (two sets) symmetrically arranged branch chains installed between the fixed frame and the moving platform, the constraints on the moving platform are generated and the moving platform only produces translational motion. (2) Each group of branch chains is composed of two branch chains. The axes of the two branch chains near the frame meet at one point. A pair of bevel gears are fixed at one end of the near frame rod and installed in mesh. Through the meshing transmission of the two gears, The movement of the near-frame rods of the two branch chains is the same, and the moving platform is further constrained to only produce two-dimensional translation in the plane, and the rigidity of the mechanism is relatively high in the moving plane perpendicular to the moving platform. (3) In the branch chain structure, the near frame rod, the far frame parallelogram, and the moving platform have simple structure, high reliability, and small motion construction quality, so it is easy to realize high-speed motion. In a word, the present invention has reasonable and compact structural design, good rigidity and stability; each branch chain is symmetrically arranged, evenly stressed, light in movement, easy to realize high-speed grasping, and has a long service life.

Although the present invention has been described above in conjunction with the drawings, the present invention is not limited to the above-mentioned specific embodiments, and the above-mentioned specific embodiments are only illustrative, rather than restrictive. Under the inspiration, many modifications can be made without departing from the gist of the present invention, and these all belong to the protection of the present invention.

Claims (2)

1. A high-speed parallel mechanism with four branch chains and two translation degrees of freedom, comprising a fixed mount, a moving platform and two branch chain groups, characterized in that, The two branch chain groups have the same structure and are symmetrically arranged between the fixed frame and the moving platform; two driving devices are fixedly connected to the fixed frame; The chain a and the branch chain b are composed of the branch chain a and the bracket b. Both the branch chain a and the bracket b include a near frame rod and two parallel and equal-length far frame rods. The two ends of the two far frame rods are respectively connected with an upper connecting shaft and a lower connecting shaft. One end of the two parallel remote frame rods is hinged with the upper connecting shaft ball respectively, and the other end is respectively hinged with the lower connecting shaft ball on the moving platform. The lower connecting shaft and the upper connecting shaft on each branch chain the shaft and the two parallel distal rods form a parallelogram structure; One end of the branch chain a and the branch chain b near the frame rod is respectively fixed to a rotating shaft, one of which is connected to the driving device, and two pairs of cones with the same structure and intermeshing are arranged on the shaft ends of the two rotating shafts. For gears, the other ends of the two near-frame rods are affixed to the upper connecting shafts in the respective branch chains, and the axes of the two bevel gears coincide with the axes of the two rotating shafts respectively and converge at one point. 2. The high-speed parallel mechanism with four branch chains and two translation degrees of freedom according to claim, characterized in that, the branch chain a and the branch chain b are driven by the meshing of the pair of bevel gears, so that the When the driving device drives one of the branch chains a and branch chain b, the other branch chain performs the same movement, which is formed by the lower connecting shaft, the upper connecting shaft and two parallel far-end rods of each branch chain The parallelogram structure of the two joints restrains the moving platform, so that the moving platform performs two-dimensional translation in the symmetrical plane of the two branch chains.

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