CN114654454A - Three-branch motion redundancy parallel mechanism driven by sliding pair - Google Patents

Abstract

The invention relates to the technical field of robots. The three-branch motion redundancy parallel mechanism driven by the moving pair has the advantages of being large in rotation angle and interior singular and easy to avoid. The technical scheme is as follows: a three-branch motion redundancy parallel mechanism driven by a sliding pair comprises a rack, a movable platform (1) and three parallel-serial branches which are connected in parallel between the rack and the movable platform and have the same structure; the parallel-serial branch comprises a first sliding pair, a combined kinematic pair, a spherical hinge, a connecting rod and a second revolute pair which are sequentially connected between the rack and the movable platform; the combined kinematic pair comprises a composite revolute pair, a second revolute pair, a first revolute pair and a third revolute pair which are sequentially connected end to end; one end of the second sliding pair and one end of the third sliding pair are both connected with the first sliding pair through the composite revolute pair, and the other end of the third sliding pair is connected with the spherical hinge.

Description

A three-branch kinematic redundant parallel mechanism driven by a mobile pair

technical field

The invention relates to the technical field of robots, in particular to a three-branch motion redundant parallel mechanism driven by a mobile pair.

Background technique

Application fields such as motion simulation and item sorting have high requirements on the speed, acceleration, accuracy, and carrying capacity of robots. Open-loop serial manipulators often cannot meet the demand and need to rely on parallel robots. These applications require that the end-moving platform of the parallel robot can output three rotations and three movements, with at least six degrees of freedom.

The most common 6DOF parallel mechanism is the Stewart platform. However, due to the constraints of multi-branch and joint travel, the rotation range of the moving platform of the mechanism is limited, and the internal singularity is difficult to avoid, and the trajectory planning is difficult, which leads to its limited application. In order to improve the rotation range of the moving platform, other novel six-degree-of-freedom parallel robots (CN108161896B, CN103926936B) have been proposed. However, these robots still have problems that are inherently bizarre and unavoidable. The motion redundant parallel robot means that the degree of freedom of the mechanism is greater than the degree of freedom of the end output motion, and the branch position can be adjusted through the motion redundant degree of freedom to avoid singular configurations. In addition, the parallel robot driven by the mobile pair has the advantages of large carrying capacity and high precision. Therefore, it is necessary to propose a kinematic redundant parallel mechanism driven by the mobile pair.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the background technology, and provide a three-branch motion redundant parallel mechanism driven by a mobile pair. The parallel mechanism should have the characteristics of large rotation angle and easy avoidance of internal singularities.

The technical scheme of the present invention is:

A three-branch motion redundant parallel mechanism driven by a mobile pair, comprising a frame, a moving platform (1), and three hybrid branches connected in parallel between the frame and the moving platform and having the same structure;

The hybrid branch includes a first moving pair, a combined moving pair, a ball joint, a connecting rod and a second rotating pair sequentially connected between the frame and the moving platform;

The combined motion pair includes a compound rotating pair, a second moving pair, a first rotating pair, and a third moving pair that are sequentially connected end to end; wherein, one end of the second moving pair and the third moving pair is connected to the first moving pair through the compound rotating pair. A moving pair is connected, and the other end of the third moving pair is connected with the ball joint.

In the combined motion pair, the second movable auxiliary lower rod slidingly matched with the second movable auxiliary guide rod and the third movable auxiliary lower rod slidingly matched with the lower part of the third movable auxiliary guide rod are both connected with the first movable auxiliary through the composite rotating pair. The movable auxiliary slider is connected; the second movable auxiliary guide rod is connected with one end of the upper part of the third movable auxiliary guide rod through the first rotation pair; the other end of the upper part of the third movable auxiliary guide rod is connected with the ball hinge.

The composite rotational secondary axis is parallel to the first rotational secondary axis and perpendicular to the second moving secondary axis and the third moving secondary axis.

Among the three hybrid branches, the three second rotation secondary axes are parallel to each other.

The first moving auxiliary guide rail, which is slidingly matched with the first moving auxiliary sliding block, is fixed to the frame.

The hinge axis of the second moving auxiliary lower rod and the compound rotating pair is coaxial with the hinge axis of the third moving auxiliary lower rod and the compound rotating pair.

In the three mixed branches, the center lines of the three first moving auxiliary guide rails are all tangent to the same circle.

The first moving pair is formed by cooperating with the first moving pair guide rail and the first moving pair sliding block.

The second moving pair is formed by cooperating with the second moving pair lower rod and the second moving pair guide rod.

The third moving pair is formed by cooperating with the third moving pair lower rod and the third moving pair guide rod.

The beneficial effects of the present invention are:

The invention proposes that the moving platform of the parallel mechanism can output three rotations and three moving motions, has the characteristics of motion redundancy, has the advantages of large rotation angle, easy avoidance of internal singularities, etc., and can be used in fields such as sorting and motion simulation.

Description of drawings

FIG. 1 is a schematic view of the three-dimensional structure of the present invention.

Detailed ways

The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

As shown in FIG. 1 , a three-branch motion redundant parallel mechanism driven by a mobile pair includes a frame (omitted from the figure), a moving platform 1 and three hybrid branches connected in parallel between the frame and the moving platform.

The hybrid branch includes a first moving auxiliary guide 1A and a first moving auxiliary sliding block 1B connected between the frame and the moving platform (the first moving auxiliary guide and the first moving auxiliary sliding block cooperate to form a first moving pair) , a compound rotating pair 1C, a second moving pair lower rod 1D, a second moving auxiliary guide rod 1E (the second moving auxiliary lower rod and the second moving auxiliary guide rod cooperate to form a second moving pair), the first rotating pair 1F, the first moving pair Three moving auxiliary lower rod 1G, third moving auxiliary guide rod 1H (the third moving auxiliary lower rod cooperates with the third moving auxiliary guide rod to form a third moving pair), ball joint 1I, connecting rod 1J and second rotating pair 1K.

Wherein: the second moving auxiliary lower rod and the third moving auxiliary lower rod are connected with the first moving auxiliary sliding block through the compound rotating pair; the second moving auxiliary guide rod is connected to the upper part of the third moving auxiliary guide rod through the first rotating pair The other end of the upper part of the third moving auxiliary guide rod is connected with the connecting rod through the ball joint (as can be seen from the figure: the lower part of the third moving auxiliary guide rod is slidingly matched with the third moving auxiliary lower rod; the third moving auxiliary guide rod The upper part is the two ends of the distance, and the two ends are respectively connected to the first rotating pair and the ball hinge); the connecting rod is connected to the moving platform through the second rotating pair; the first moving pair guide rail is fixed with the frame; the compound rotating The secondary axis is parallel to the first rotational secondary axis and perpendicular to the second moving secondary axis and the third moving secondary axis.

Among the three hybrid branches: the three second rotation axes are parallel to each other.

As a recommendation: in the three mixed branches, the centerlines of the three first moving auxiliary guide rails are all tangent to the same circle.

In this embodiment, the driving pair is a moving pair in each hybrid branch, and the driving method can be a ball screw driven by a motor (omitted in the figure); the parallel mechanism has 9 degrees of freedom, which can be completely controlled by the driving pair, and the moving platform It can output three rotations and three movements.

Claims (8)

1. A three-branch motion redundant parallel mechanism driven by a mobile pair, comprising a frame, a moving platform (1), and three hybrid branches connected in parallel between the frame and the moving platform and having the same structure; The hybrid branch includes a first moving pair, a combined moving pair, a ball joint (1I), a connecting rod (1J) and a second rotating pair (1K) sequentially connected between the frame and the moving platform; The combined motion pair includes a compound rotating pair (1C), a second moving pair, a first rotating pair (1F), and a third moving pair that are sequentially connected end to end; wherein, one end of the second moving pair and the third moving pair are both. The compound rotating pair is connected with the first moving pair, and the other end of the third moving pair is connected with the spherical hinge. 2. The three-branch motion redundant parallel mechanism driven by the mobile pair according to claim 1, characterized in that: in the combined motion pair, the second mobile pair slide-fitted with the second mobile pair guide rod (1E) lowers The rod (1D) and the third moving auxiliary lower rod (1G) slidingly matched with the lower part of the third moving auxiliary guide rod (1H) are connected with the first moving auxiliary sliding block (1B) through the compound rotating pair; the second moving auxiliary The guide rod is connected with one end of the upper part of the third moving auxiliary guide rod through the first rotating pair; the other end of the upper part of the third moving auxiliary guide rod is connected with the ball hinge. 3 . The three-branch motion redundant parallel mechanism driven by the mobile pair according to claim 2 , wherein the composite rotational axis is parallel to the first rotational axis and perpendicular to the second mobile axis and the third rotational axis. 4 . Move the secondary axis. 4 . The three-branch motion redundant parallel mechanism driven by the mobile pair according to claim 3 , wherein in the three hybrid branches, the axes of the three second rotating pairs are parallel to each other. 5 . 5 . The three-branch motion redundant parallel mechanism driven by the moving pair according to claim 4 , wherein the first moving auxiliary guide rail slidingly matched with the first moving auxiliary sliding block is fixed to the frame. 6 . 6 . The three-branch motion redundant parallel mechanism driven by the moving pair according to claim 5 , wherein the hinge axis of the second moving pair lower lever and the compound rotating pair is hinged, and the third moving pair lower lever is connected with the third moving pair lower lever. 7 . The hinge axes of the compound rotating pair are coaxial. 7 . The three-branch motion redundant parallel mechanism driven by the mobile pair according to claim 6 , wherein in the three mixed branches, the centerlines of the three first mobile pair guide rails are all tangent to the same circumference. 8 . 8. The three-branch motion redundant parallel mechanism driven by the mobile pair according to claim 7 is characterized in that: The first moving pair is formed by cooperating with the first moving auxiliary guide rail (1A) and the first moving auxiliary sliding block (1B); The second moving pair is formed by cooperating with the second moving pair lower rod (1D) and the second moving pair guide rod (1E); The third moving pair is formed by cooperating with the third moving pair lower rod (1G) and the third moving pair guide rod (1H).

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