A new symmetrical metamorphic parallel mechanism with additional rotation axis

Abstract

The present invention provides a novel symmetrical metamorphic parallel mechanism with an additional rotating axis. This mechanism can change the degree of freedom of rotation, eliminating the need for downtime and replacement when producing different products, resulting in high production efficiency. The mechanism comprises a fixed platform and a movable platform, characterized in that the fixed platform and the movable platform are connected by a first branch chain, a second branch chain, and a third branch chain. These three metamorphic branches have the same structure, namely, PRRRR branches.

Description

Technical Field

[0001] The present invention belongs to the field of robotics technology, and in particular relates to a novel symmetrical metamorphic parallel mechanism capable of adding a rotating axis. Background Art

[0002] Parallel mechanisms are currently attracting significant attention in the industrial robotics field due to their high precision, high stiffness, rapid response, and excellent load capacity. They are widely used in applications such as machining, automated production lines, and motion simulators, and have become a hot topic of research. However, the parallel mechanisms currently used in most production lines only have fixed rotational degrees of freedom. This limits their flexibility and makes it difficult to meet rapidly changing market demands. Each time a new product is produced, the production line must be shut down to replace the parallel mechanism with a different degree of freedom. This is particularly true in the cosmetics packaging industry, where fashion trends drive significant annual changes in cosmetics packaging. This leads to frequent changes in the cosmetics packaging production line, increasing downtime and reducing production efficiency. Summary of the Invention

[0003] In view of the disadvantage that the existing parallel mechanism has only fixed rotational freedom and needs to be stopped to replace the parallel mechanism when producing different products, resulting in low production efficiency, the present invention provides a new symmetrical variable cell parallel mechanism that can add a rotating axis, which can change the rotational freedom. It does not require shutdown to replace when producing different products, and has high production efficiency.

[0004] A novel symmetrical variable cell parallel mechanism capable of adding a rotating axis comprises a fixed platform and a movable platform, and is characterized in that the fixed platform and the movable platform are connected by a first branch chain, a second branch chain, and a third branch chain, and the three first branch chains, the second branch chain, and the third branch chain have the same structure, and are all PRRRR branches.

[0005] It is further characterized by:

[0006] One end of the first branch chain is installed on the fixed platform through a moving pair, and the first rotating pair is installed on the moving pair, and the axial direction of the first rotating pair is always perpendicular to the fixed platform; the second rotating pair is connected to the first rotating pair through a connecting rod, and the direction of the second rotating pair is always perpendicular to the fixed platform; the third rotating pair is connected to the second rotating pair through a connecting rod, and the direction is always parallel to the fixed platform; the arc groove rotating pair is connected to the third rotating pair through a connecting rod, and the fourth rotating pair is connected to the arc groove rotating pair through a connecting rod, and the third rotating pair and the fourth rotating pair always intersect at one point, which is called the branch center point of the first branch chain; the other end of the first branch chain is installed on the moving platform through an arc groove pin pair, and the fourth rotating pair is connected to the arc groove pin pair; the fourth rotating pair moves in the arc groove of the arc groove pin pair to change the position of the intersection of the axes of the third rotating pair and the fourth rotating pair of the first branch chain, that is, the position of the branch center point, thereby changing the working state of the mechanism;

[0007] One end of the second branch chain is installed on the fixed platform through a moving pair, and the first rotating pair is installed on the moving pair, and the axial direction of the first rotating pair is always perpendicular to the fixed platform; the second rotating pair is connected to the first rotating pair through a connecting rod, and the direction of the second rotating pair is always perpendicular to the fixed platform; the third rotating pair is connected to the second rotating pair through a connecting rod, and the direction is always parallel to the fixed platform; the arc groove rotating pair is connected to the third rotating pair through a connecting rod, and the fourth rotating pair is connected to the arc groove rotating pair through a connecting rod, and the third rotating pair and the fourth rotating pair always intersect at one point, which is called the branch center point of the second branch chain; the other end of the second branch chain is installed on the moving platform through an arc groove pin pair, and the fourth rotating pair is connected to the arc groove pin pair; the fourth rotating pair moves in the arc groove of the arc groove pin pair to change the position of the intersection of the axes of the third rotating pair and the fourth rotating pair of the second branch chain, that is, the position of the branch center point, thereby changing the working state of the mechanism;

[0008] One end of the third branch chain is installed on the fixed platform through a moving pair, and the first rotating pair is installed on the moving pair, and the axial direction of the first rotating pair is always perpendicular to the fixed platform; the second rotating pair is connected to the first rotating pair through a connecting rod, and the direction of the second rotating pair is always perpendicular to the fixed platform; the third rotating pair is connected to the second rotating pair through a connecting rod, and the direction is always parallel to the fixed platform; the arc groove rotating pair is connected to the third rotating pair through a connecting rod, and the fourth rotating pair is connected to the arc groove rotating pair through a connecting rod, and the third rotating pair and the fourth rotating pair always intersect at one point, which is called the branch center point of the third branch chain; the other end of the third branch chain is installed on the moving platform through an arc groove pin pair, and the fourth rotating pair is connected to the arc groove pin pair; the fourth rotating pair moves in the arc groove of the arc groove pin pair to change the position of the intersection of the axis of the third rotating pair and the fourth rotating pair of the third branch chain, that is, the position of the branch center point, thereby changing the working state of the mechanism;

[0009] The three moving pairs of the first branch chain, the second branch chain and the third branch chain are driving pairs and are driven by electric push rods.

[0010] The beneficial effects of the present invention are as follows: the new variable cell parallel mechanism proposed in the present invention can control the number of overlapping branch center points by simply controlling the movement of the fourth rotating pair in the circular arc groove of the circular arc groove pin pair, and can switch the space 1R2T, 2R2T, and 3R2T movements; the three branch structures are exactly the same and can be applied to assembly line processing from simple to complex packaging. Different working states can be changed according to product requirements, and a highly flexible production process can be easily realized, production costs can be reduced, and there is no need to stop the machine to replace the parallel mechanism during the switching process, thereby reducing the downtime of the production line and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0012] Figure 2 It is a schematic diagram of the method of changing the branch center point of the present invention;

[0013] Figure 3 This is a schematic diagram of the working state of the 2R2T of the present invention;

[0014] Figure 4 It is a schematic diagram of the working state of 3R2T of the present invention.

[0015] In the figure: 1 fixed platform; 2 first branch chain; 21 moving pair; 22 first rotating pair; 23 second rotating pair; 24 third rotating pair; 25 arc groove rotating pair; 26 fourth rotating pair; 27 arc groove pin pair; 3 second branch chain; 31 moving pair; 32 first rotating pair; 33 second rotating pair; 34 third rotating pair; 35 arc groove rotating pair; 36 fourth rotating pair; 37 arc groove pin pair; 4 third branch chain; 41 moving pair; 42 first rotating pair; 43 second rotating pair; 44 third rotating pair; 45 arc groove rotating pair; 46 fourth rotating pair; 47 arc groove pin pair; 5 moving platform. DETAILED DESCRIPTION

[0016] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0017] See Figure 1 A new type of symmetrical variable cell parallel mechanism that can add a rotating axis includes a fixed platform 1 and a movable platform 5. The fixed platform 1 and the movable platform 5 are connected by a first branch chain 2, a second branch chain 3, and a third branch chain 4. The three branches have the same structure and are all PRRRR branches. There is an arc groove rotating pair 25 between the third rotating pair 24 and the fourth rotating pair 26. It is the center of the arc groove of the arc groove pin pair. By moving the fourth rotating pair 26 in the arc groove of the arc groove pin pair 27, the intersection position of the axes of the third rotating pair 24 and the fourth rotating pair 26 can be changed, thereby controlling the number of branch center points, and ultimately achieving the purpose of changing the working state of the mechanism. (Wherein, P represents the moving pair and is the active drive pair of this mechanism, and R represents the rotating pair).

[0018] One end of the first branch chain 2 is mounted on the fixed platform 1 through the moving pair 21, and the first rotating pair 22 is mounted on the moving pair 21, and the axis direction of the first rotating pair 21 is always perpendicular to the fixed platform; the second rotating pair 23 is connected to the first rotating pair 22 through a connecting rod, and the second rotating pair 23 The direction is always perpendicular to the fixed platform; the third rotational pair 24 is connected to the second rotational pair 23 by a connecting rod, and the direction of the third rotational pair 24 is always parallel to the fixed platform; the arc groove rotational pair 25 is connected to the third rotational pair 24 by a connecting rod, and the fourth rotational pair 26 is connected to the arc groove rotational pair 25 by a connecting rod, and the extension lines of the third rotational pair 24 and the fourth rotational pair 25 always intersect at one point, which is called the branch center point of the first branch chain 2; the other end of the first branch chain 2 is installed on the moving platform through the arc groove pin pair 27, and the fourth rotational pair 26 is connected to the arc groove pin pair 27; the fourth rotational pair 26 moves in the arc groove of the arc groove pin pair 27 to change the position of the intersection of the axes of the third rotational pair 24 and the fourth rotational pair 26 of the first branch chain 2, that is, the position of the branch center point, thereby changing the working state of the mechanism.

[0019] One end of the second branch chain 3 is mounted on the fixed platform 1 through a moving pair 31, and the first rotating pair 32 is mounted on the moving pair 31, and the axis direction of the first rotating pair 32 is always perpendicular to the fixed platform; the second rotating pair 33 is connected to the first rotating pair 32 through a connecting rod, and the direction of the second rotating pair 33 is always perpendicular to the fixed platform; the third rotating pair 34 is connected to the second rotating pair 33 through a connecting rod, and the direction of the third rotating pair 34 is always parallel to the fixed platform; the arc groove rotating pair 35 is connected to the third rotating pair 34 through a connecting rod, and the fourth rotating pair 3 6 is connected to the arc groove rotation pair 35 through a connecting rod, and the third rotation pair 34 and the fourth rotation pair 36 always intersect at a point, which is called the branch center point of the second branch chain 3; the other end of the second branch chain 3 is mounted on the moving platform through the arc groove pin pair 37, and the fourth rotation pair 36 is connected to the arc groove pin pair 37; the fourth rotation pair 36 moves in the arc groove of the arc groove pin pair 37, thereby changing the position of the intersection of the axes of the third rotation pair 34 and the fourth rotation pair 36 of the second branch chain 3, that is, the position of the branch center point, thereby changing the working state of the mechanism.

[0020] One end of the third branch chain 4 is mounted on the fixed platform 1 through a moving pair 41, and the first rotating pair 42 is mounted on the moving pair 41, and the axis direction of the first rotating pair 42 is always perpendicular to the fixed platform; the second rotating pair 43 is connected to the first rotating pair 42 through a connecting rod, and the direction of the second rotating pair 43 is always perpendicular to the fixed platform; the third rotating pair 44 is connected to the second rotating pair 43 through a connecting rod, and the direction of the third rotating pair 44 is always parallel to the fixed platform; the circular arc groove rotating pair 45 is connected to the third rotating pair 44 through a connecting rod, and the fourth rotating pair 46 is connected to the circular arc groove rotating pair 45 through a connecting rod. The third rotating pair 44 and the fourth rotating pair 45 always intersect at one point, which is called the branch center point of the third branch chain 4; the other end of the third branch chain 4 is installed on the moving platform through the arc groove pin pair 47, and the fourth rotating pair 46 is connected to the arc groove pin pair 47; the fourth rotating pair 46 moves in the arc groove of the arc groove pin pair 47, thereby changing the position of the intersection of the axis of the third rotating pair 44 and the fourth rotating pair 46 of the third branch chain 4, that is, the position of the branch center point, thereby changing the working state of the mechanism; the moving pair 21, the moving pair 31, and the moving pair 41 are driving pairs, and the input motion is realized by the electric push rod.

[0021] Figure 2 This is a method of changing the position of the branch center point. The center of the circular arc groove pin pair 27 is located at the axis position of the rotating pair circular arc groove rotating pair 25. The fourth rotating pair 26 can move in the circular arc groove, and the axis of the fourth rotating pair 26 can be located in position 1 and position 2.

[0022] See Figure 1 、 Figure 3 、 Figure 4When the axis of the fourth rotational pair 25 of the first branch chain 2, the axis of the fourth rotational pair 35 of the second branch chain 3, and the axis of the fourth rotational pair 45 of the third branch chain 4 are all in position 2, the center points of the three branches of the mechanism do not coincide, such as Figure 1 As shown, its degree of freedom is 1R2T, which means it can rotate around the z-axis and move in the xoy plane. When the axis of the fourth rotational pair 25 of the first branch chain 2 and the axis of the fourth rotational pair 35 of the second branch chain 3 are both in position 1, and the axis of the fourth rotational pair 45 of the third branch chain 4 is in position 2, the mechanism has only two branch center points that coincide, as shown in Figure 2. Figure 3 As shown, its degree of freedom is 2R2T. The additional axis of rotation is the line connecting the branch centers, that is, the u-axis, which can rotate around the z-axis and the u-axis and move in the xoy plane. When the fourth rotation pair 25 axis of the first branch chain 2, the fourth rotation pair 35 axis of the second branch chain 3, and the fourth rotation pair 45 axis of the third branch chain 4 are all in position 1, the three branch centers of the mechanism coincide, as shown in FIG. Figure 4 As shown, its degrees of freedom are 3R2T;

[0023] The beneficial effects of the present invention are as follows: the new type of variable cell parallel mechanism proposed in the present invention can realize spatial 1R2T, 2R2T, and 3R2T movements by controlling the number of overlapping branch center points; the three branch structures are exactly the same and can be applied to assembly line processing from simple to complex packaging. Different working states can be changed according to product requirements, which can realize highly flexible production processes, reduce production costs, reduce production line downtime, and improve production efficiency.

[0024] The PRRRR branch chain represents a chain of branches connected in the order of translation pair, rotation pair, rotation pair, rotation pair, and rotation pair. 1R2T represents one rotation and two translations; 2R2T represents two rotations and two translations; and 3R2T represents three rotations and two translations.

Claims

1. A novel symmetrical metamorphic parallel mechanism capable of adding a rotating axis, comprising a fixed platform and a movable platform, characterized in that: The fixed platform and the movable platform are connected by a first branch chain, a second branch chain, and a third branch chain, wherein the first branch chain, the second branch chain, and the third branch chain have the same structure, and are all PRRRR branches; One end of each branch chain is mounted on the fixed platform via a moving pair. The first rotating pair is mounted on the moving pair, and the axis direction of the first rotating pair is always perpendicular to the fixed platform. The second rotating pair is connected to the first rotating pair via a connecting rod, and the direction of the second rotating pair is always perpendicular to the fixed platform. The third rotating pair is connected to the second rotating pair via a connecting rod, and the direction is always parallel to the fixed platform. The arc groove rotating pair is connected to the third rotating pair through a connecting rod, and the fourth rotating pair is connected to the arc groove rotating pair through a connecting rod, and the third rotating pair and the fourth rotating pair always intersect at one point, which is called the branch center point of the branch chain; the other end of each branch chain is installed on the moving platform through an arc groove pin pair, and the fourth rotating pair is connected to the arc groove pin pair; the fourth rotating pair moves in the arc groove of the arc groove pin pair, thereby changing the position of the intersection of the axis of the third rotating pair and the fourth rotating pair in the branch chain, that is, the position of the branch center point, thereby changing the working state of the mechanism.

2. The novel symmetrical metamorphic parallel mechanism capable of adding a rotating axis according to claim 1, characterized in that: The three moving pairs of the first branch chain, the second branch chain and the third branch chain are driving pairs, which are driven by electric push rods.

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