Two-rotation-one-movement super-redundant drive parallel mechanism with compound rotating pair

Abstract

The present invention relates to a two-rotation-one-movement super-redundant drive parallel mechanism containing a composite rotating pair, which includes a fixed platform, a moving platform, and six motion branches arranged between the fixed platform and the moving platform, the first branch chain and the third branch chain are both UPR branches, the second branch chain and the fourth branch chain are both RPU branches, and the first branch chain, the second branch chain, the third branch chain and the fourth branch chain are symmetrically arranged in a square along a counterclockwise direction at the corners of the fixed platform and the moving platform, the fifth branch chain and the sixth branch chain are both UPR branches, and the fifth branch chain and the sixth branch chain are arranged on the diagonal of the first branch chain and the third branch chain. The present invention provides a two-rotation-one-movement parallel mechanism with two continuous rotating shafts and one moving shaft, thereby realizing the super-redundant drive of the parallel mechanism with few joints.

Description

Technical Field

[0001] The invention belongs to the technical field of parallel robots, and in particular relates to a two-rotation-one-movement super-redundant drive parallel mechanism containing a composite rotating pair. Background Art

[0002] The use of appropriate parallel mechanisms with fewer degrees of freedom can reduce the costs of manufacturing, control and maintenance. Therefore, parallel mechanisms with fewer degrees of freedom have become a hot topic and frontier of academic and industrial circles, and have been successfully applied in many fields. Among them, the three-degree-of-freedom parallel mechanism with two rotations and one movement (abbreviated as 2R1T) is the most representative type of parallel mechanism with fewer degrees of freedom. Successful examples of 2R1T parallel mechanisms as the main mechanism of high-end manufacturing equipment include hybrid robots such as Tricept, Ecospeed and Exechon. These hybrid robots are widely used in aerospace and automotive fields and have achieved good economic benefits. The 2R1T three-degree-of-freedom parallel mechanism has two rotating axes, and the geometric relationship between the two rotating axes is closely related to the motion performance of this type of mechanism. However, the two rotating axes of most 2R1T three-degree-of-freedom parallel mechanisms are not continuous rotating axes, which brings about the complexity of the mechanism kinematic model, increases the difficulty of trajectory planning, kinematic parameter calibration and motion control, and other problems.

[0003] Compared with the serial mechanism, the parallel mechanism has the advantages of compact structure, high rigidity, high precision, high speed, strong load-bearing capacity, small inertia, good stability, and simple inverse kinematics. However, the disadvantages of the parallel mechanism, such as small working space and the existence of singular configurations, cannot be ignored. The redundant drive parallel mechanism refers to a parallel mechanism in which the number of its drive devices is greater than the number of degrees of freedom. From the perspective of kinematics, one or more drive devices are redundant. Removing these drive devices does not affect the motion characteristics. However, in heavy-duty operating equipment, in order to improve the load-bearing capacity of the mechanism and increase the rigidity and stability of the mechanism, the drive system is usually designed as a redundant drive. Therefore, the redundant drive has the characteristics of making the mechanism structure have local symmetry and no singular configurations, thereby optimizing the performance of the mechanism such as rigidity and load-bearing capacity. By adding redundant drive branches on the basis of the original mechanism, the singularity of the mechanism can be reduced, its available working space can be increased, and some performances of the mechanism can be improved, such as enhancing the rigidity of the mechanism, increasing the load-bearing capacity of the mechanism, optimizing the input force of the drive, and reducing the internal force of the mechanism joints. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a parallel mechanism with two rotations and one movement, having two continuous rotating axes and one moving axis. The movement planes of the first branch chain and the third branch chain are perpendicular to the movement planes of the second branch chain and the fourth branch chain. The four branches are symmetrically distributed at the four geometric vertices of the square of the moving platform and the fixed platform. In addition to the continuous rotating axis formed by two continuous rotational freedom axes, it also has three redundant branches, thereby realizing super-redundant drive of the parallel mechanism with few joints.

[0005] The technical solution adopted by the present invention is a two-rotation-one-movement super-redundant drive parallel mechanism containing a composite rotating pair, which includes a fixed platform, a moving platform and six motion branches arranged between the fixed platform and the moving platform, the fixed platform and the moving platform are both square, and six motion branches are arranged between the fixed platform and the moving platform; the six motion branches include a first branch chain, a second branch chain, a third branch chain, a fourth branch chain, a fifth branch chain and a sixth branch chain, and each of the motion branches includes a driving rod, the first branch chain, the second branch chain, the third branch chain and the fourth branch chain are symmetrically arranged in a square along a counterclockwise direction at the corners of the fixed platform and the moving platform, and the first branch chain and the third branch chain are arranged diagonally, and the first branch chain and the third branch chain are both U PR branch chain, and the lower ends of the driving rods in the first branch chain and the third branch chain are respectively connected to the fixed platform through the first universal joint and the third universal joint, the upper ends of the driving rods in the first branch chain and the third branch chain are respectively connected to the moving platform through the first rotation pair and the third rotation pair, and the upper connecting rod and the lower connecting rod on the driving rod in the first branch chain and the third branch chain are respectively connected through the first moving pair and the third moving pair, the second branch chain and the fourth branch chain are diagonally arranged, the second branch chain and the fourth branch chain are both RPU branches, and the lower ends of the driving rods in the second branch chain and the fourth branch chain are respectively connected to the fixed platform through the second rotation pair and the fourth rotation pair, the upper ends of the driving rods in the second branch chain and the fourth branch chain are respectively connected through the second universal joint and the fourth universal joint The fifth and sixth branches are arranged on the diagonals of the first and third branches, and the fifth and sixth branches are UPR branches, and the lower ends of the driving rods in the fifth and sixth branches are connected to the fixed platform through the fifth universal joint and the sixth universal joint, respectively, and the upper ends of the driving rods in the fifth and sixth branches are connected to the moving platform through the common first rotation pair and the third rotation pair, and the upper and lower connecting rods on the driving rods in the fifth and sixth branches are connected through the fifth and sixth moving pairs respectively; the first universal joint in the first branch The outer rotation secondary axis is collinear with the outer rotation secondary axis of the third universal joint in the third branch chain, and the axis passes through the geometric center of the fixed platform, and its axis direction is the first rotation direction of the super-redundant drive parallel mechanism, and the outer rotation secondary axis of the second universal joint in the second branch chain is collinear with the outer rotation secondary axis of the fourth universal joint in the fourth branch chain, and the axis passes through the geometric center of the moving platform, and its axis direction is the second rotation direction of the super-redundant drive parallel mechanism, and the direction of the line connecting the geometric center of the fixed platform and the geometric center of the moving platform is the direction of the freedom of movement of the super-redundant drive parallel mechanism, and by driving the driving rods in each moving branch chain to move, the super-redundant drive parallel mechanism can be realized in two-dimensional rotation and one-dimensional movement in the space.

[0006] Further, the inner rotation secondary axis of the first universal joint in the first branch chain is parallel to the first rotation secondary axis, and the inner rotation secondary axis of the first universal joint and the axis of the first rotation secondary are both perpendicular to the first moving secondary axis; the inner rotation secondary axis of the second universal joint in the second branch chain is parallel to the second rotation secondary axis, and the inner rotation secondary axis of the second universal joint and the second rotation secondary axis are both perpendicular to the second moving secondary axis; the inner rotation secondary axis of the third universal joint in the third branch chain is parallel to the third rotation secondary axis, and the inner rotation secondary axis of the third universal joint and the third rotation secondary axis are both perpendicular to the third moving secondary axis line; the inner side rotation secondary axis of the fourth universal joint in the fourth branch chain is parallel to the fourth rotation secondary axis, and the inner side rotation secondary axis of the fourth universal joint and the fourth rotation secondary axis are both perpendicular to the fourth movable secondary axis; the inner side rotation secondary axis of the fifth universal joint in the fifth branch chain is parallel to the first rotation secondary axis, and the inner side rotation secondary axis of the fifth universal joint and the first rotation secondary axis are both perpendicular to the fifth movable secondary axis; the inner side rotation secondary axis of the sixth universal joint in the sixth branch chain is parallel to the third rotation secondary axis, and the inner side rotation secondary axis of the sixth universal joint and the third rotation secondary axis are both perpendicular to the sixth movable secondary axis.

[0007] Preferably, the outer rotating pairs of the first universal joint, the third universal joint, the fifth universal joint and the sixth universal joint are respectively connected to the fixed platform, and the inner rotating pairs of the first universal joint, the third universal joint, the fifth universal joint and the sixth universal joint are respectively connected to the lower connecting rod in the corresponding driving rod, the outer rotating pairs of the second universal joint and the fourth universal joint are respectively connected to the moving platform, and the inner rotating pairs of the second universal joint and the fourth universal joint are respectively connected to the upper connecting rod in the corresponding driving rod.

[0008] Preferably, the second rotation secondary axis is parallel to the fourth rotation secondary axis, and the fourth rotation secondary is parallel to the outer rotation secondary axis of the first universal joint, the third universal joint, the fifth universal joint and the sixth universal joint, the center point of the second rotation secondary axis and the center point of the fourth rotation secondary axis are all on the same straight line with the geometric center of the fixed platform, and the center point of the outer rotation secondary axis of the first universal joint, the third universal joint, the fifth universal joint and the sixth universal joint are all on the same straight line with the geometric center of the fixed platform.

[0009] Preferably, the first rotation secondary axis is parallel to the third rotation secondary axis, and the third rotation secondary axis is parallel to the outer rotation secondary axis of the second universal joint and the fourth universal joint, the center point of the first rotation secondary axis, the center point of the third rotation secondary axis and the geometric center of the moving platform are all on the same straight line, and the center point of the outer rotation secondary axis of the second universal joint and the fourth universal joint and the geometric center of the moving platform are all on the same straight line.

[0010] Preferably, the outer rotation secondary axis of the first universal joint connected to the fixed platform, the outer rotation secondary axis of the third universal joint, the outer rotation secondary axis of the fifth universal joint and the outer rotation secondary axis of the sixth universal joint are all parallel to the first rotation secondary axis and the third rotation secondary axis connected to the moving platform; the inner rotation secondary axis of the first universal joint and the inner rotation secondary axis of the third universal joint connected to the fixed platform are all parallel to the first rotation secondary axis, the third rotation secondary axis, the outer rotation secondary axis of the second universal joint and the outer rotation secondary axis of the fourth universal joint connected to the moving platform; the outer rotation secondary axis of the second universal joint is collinear with the outer rotation secondary axis of the fourth universal joint and passes through the geometric center point of the moving platform; the outer rotation secondary axis of the first universal joint is collinear with the outer rotation secondary axis of the third universal joint and passes through the geometric center point of the fixed platform.

[0011] Further, when the fixed platform is parallel to the moving platform, the projection of the first rotating pair in the fifth branch chain on the fixed platform is the midpoint of a line between a center point of an outer rotating pair of the first universal joint and a center point of an outer rotating pair of the fifth universal joint, and the outer rotating pair axis of the fifth universal joint, the outer rotating pair axis of the first universal joint and the outer rotating pair axis of the third universal joint are parallel to each other, and the center point of the outer rotating pair axis of the fifth universal joint, the center point of the outer rotating pair axis of the first universal joint and the center point of the outer rotating pair axis of the third universal joint are collinear, and are all on the opposite side of the fixed platform. diagonal line; when the fixed platform is parallel to the moving platform, the projection of the third rotating pair in the sixth branch chain on the fixed platform is the midpoint of the line between the center point of the outer rotating pair of the third universal joint and the center point of the outer rotating pair of the sixth universal joint, and the outer rotating pair axis of the sixth universal joint, the outer rotating pair axis of the first universal joint and the outer rotating pair axis of the third universal joint are parallel to each other, and the center point of the outer rotating pair axis of the sixth universal joint, the center point of the outer rotating pair axis of the first universal joint and the center point of the outer rotating pair axis of the third universal joint are collinear, and are all on the diagonal line of the fixed platform.

[0012] Furthermore, the axes of the outer rotating pair of the first universal joint, the outer rotating pair of the third universal joint, the outer rotating pair of the fifth universal joint, the outer rotating pair of the sixth universal joint, the second rotating pair and the fourth rotating pair connected to the fixed platform are not in the same plane in space and are perpendicular to the axes of the outer rotating pair of the first rotating pair, the third rotating pair, the outer rotating pair of the second universal joint and the fourth universal joint connected to the movable platform.

[0013] The characteristics and beneficial effects of the present invention are:

[0014] 1. The two-rotation-one-movement super-redundant drive parallel mechanism with a composite rotating pair provided by the present invention has two continuous rotating shafts, good motion decoupling, and stronger practicality.

[0015] 2. The two-rotating and one-moving super-redundant drive parallel mechanism containing a composite rotating pair provided by the present invention has the advantages of reasonable structure, high overall structural rigidity of the mechanism, high motion accuracy, easy control, etc., and is suitable for occasions such as processing of high-precision, high-rigidity, high-load, and high-hardness materials.

[0016] 3. The two-rotating and one-moving super-redundant drive parallel mechanism containing a composite rotating pair provided by the present invention has the following characteristics: the motion planes of the first branch chain coincide with the motion planes of the third branch chain, the motion planes of the second branch chain coincide with the motion planes of the fourth branch chain, the motion planes of the first branch chain and the third branch chain are perpendicular to the motion planes of the second branch chain and the fourth branch chain, and the four branches are symmetrically distributed at the four geometric vertices of the square of the moving and fixed platforms, so the kinematic analysis is simplified and real-time control is convenient.

[0017] 4. The two-rotating and one-moving super-redundant drive parallel mechanism with a composite rotating pair provided by the present invention establishes a deformation coordination model and a force coordination model of the super-redundant drive parallel mechanism through the motion accuracy and force state of the super-redundant drive branch chain or the joint adjustment mechanism, and shares the mapping relationship between the branch chain deformation and the force distribution of the super-redundant drive parallel mechanism, so as to realize the adjustable mechanical characteristics of the super-redundant drive parallel mechanism; at the same time, by reasonably allocating the number of redundant branches, the redundant characteristics of the super-redundant drive parallel mechanism can be made variable, which has the advantage of better mechanical controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the two-rotation-one-movement super-redundant drive parallel mechanism containing a composite rotating pair of the present invention;

[0019] Figure 2 It is a top view of the overall structure of the two-rotation-one-movement super-redundant drive parallel mechanism containing a composite rotating pair of the present invention;

[0020] Figure 3 It is a schematic diagram of each component of the present invention;

[0021] Figure 4It is a front view of the connection between the composite R pair, the branch chain and the moving platform of the present invention;

[0022] Figure 5 It is a side view of the connection of the composite R pair, the branch chain and the moving platform of the present invention.

[0023] Main reference numerals:

[0024] 1-fixed platform; 2-moving platform; 3-first branch chain; 31-first universal joint; 32-first moving pair; 33-first rotating pair; 4-second branch chain; 41-second rotating pair; 42-second moving pair; 43-second universal joint; 5-third branch chain; 51-third universal joint; 52-third moving pair; 53-third rotating pair; 6-fourth branch chain; 61-fourth rotating pair; 62-fourth moving pair; 63-fourth universal joint; 7-fifth branch chain; 71-fifth universal joint; 72-fifth moving pair; 8-sixth branch chain; 81-sixth universal joint; 82 sixth moving pair. DETAILED DESCRIPTION

[0025] In order to fully describe the technical content, structural features, objectives and effects of the present invention, the following will be described in detail with reference to the accompanying drawings.

[0026] The present invention provides a two-rotation-one-movement super-redundant drive parallel mechanism including a composite rotating pair, such as Figure 1 to Figure 3 As shown, it includes a fixed platform 1, a moving platform 2 and six motion branches arranged between the fixed platform 1 and the moving platform 2. The fixed platform 1 and the moving platform 2 are both square, and the moving platform 2 is arranged above the fixed platform 1. Six motion branches are arranged between the fixed platform 1 and the moving platform 2. The six motion branches include a first branch chain 3, a second branch chain 4, a third branch chain 5, a fourth branch chain 6, a fifth branch chain 7 and a sixth branch chain 8, and each motion branch chain includes a driving rod. The first branch chain 3, the second branch chain 4, the third branch chain 5 and the fourth branch chain 6 are symmetrically arranged in a square shape counterclockwise at the corners of the fixed platform 1 and the moving platform 2.

[0027] like Figure 3As shown, the first branch chain 3 and the third branch chain 5 are arranged diagonally, and both the first branch chain 3 and the third branch chain 5 are UPR branches, and the lower ends of the driving rods in the first branch chain 3 and the third branch chain 5 are connected to the fixed platform 1 through the first universal joint 31 and the third universal joint 51 respectively, and the upper ends of the driving rods in the first branch chain 3 and the third branch chain 5 are connected to the moving platform 2 through the first rotation pair 33 and the third rotation pair 53 respectively, and the upper connecting rod and the lower connecting rod on the driving rod in the first branch chain 3 and the third branch chain 5 are connected through the first moving pair 32 and the third moving pair 52 respectively. The inner rotation pair axis of the first universal joint 31 in the first branch chain 3 is parallel to the axis of the first rotating pair 33, and the inner rotation pair axis of the first universal joint 31 and the axis of the first rotating pair 33 are both perpendicular to the axis of the first moving pair 32. The inner rotational pair axis of the third universal joint 51 in the third branch chain 5 is parallel to the axis of the third rotational pair 53 , and both the inner rotational pair axis of the third universal joint 51 and the axis of the third rotational pair 53 are perpendicular to the axis of the third movement pair 52 .

[0028] like Figure 3 As shown, the second branch chain 4 and the fourth branch chain 6 are arranged diagonally, and the second branch chain 4 and the fourth branch chain 6 are both RPU branches, and the lower ends of the driving rods in the second branch chain 4 and the fourth branch chain 6 are connected to the fixed platform 1 through the second rotating pair 41 and the fourth rotating pair 61 respectively, and the upper ends of the driving rods in the second branch chain 4 and the fourth branch chain 6 are connected to the moving platform 2 through the second universal joint 43 and the fourth universal joint 63 respectively, and the upper connecting rod and the lower connecting rod on the driving rod in the second branch chain 4 and the fourth branch chain 6 are connected through the second moving pair 42 and the fourth moving pair 62 respectively. The inner rotating pair axis of the second universal joint 43 in the second branch chain is parallel to the axis of the second rotating pair 41, and the inner rotating pair axis of the second universal joint 43 and the axis of the second rotating pair 41 are both perpendicular to the axis of the second moving pair 42. The inner rotational secondary axis of the fourth universal joint 63 in the fourth branch chain 6 is parallel to the axis of the fourth rotational secondary 61 , and both the inner rotational secondary axis of the fourth universal joint 63 and the axis of the fourth rotational secondary 61 are perpendicular to the axis of the fourth movement secondary 62 .

[0029] like Figure 3 to Figure 5As shown, the fifth branch chain 7 and the sixth branch chain 8 are arranged on the diagonal lines of the first branch chain 3 and the third branch chain 5, the fifth branch chain 7 and the sixth branch chain 8 are both UPR branches, and the lower ends of the driving rods in the fifth branch chain 7 and the sixth branch chain 8 are connected to the fixed platform 1 through the fifth universal joint 71 and the sixth universal joint 81 respectively, the upper ends of the driving rods in the fifth branch chain 7 and the sixth branch chain 8 are connected to the moving platform through the common first rotation pair 33 and the third rotation pair 53 respectively, and the upper connecting rod and the lower connecting rod on the driving rod in the fifth branch chain 7 and the sixth branch chain 8 are connected through the fifth moving pair 72 and the sixth moving pair 82 respectively. The inner rotation pair axis of the fifth universal joint 71 in the fifth branch chain 7 is parallel to the first rotation pair axis 33, and the inner rotation pair axis of the fifth universal joint 71 and the first rotation pair axis 33 are perpendicular to the axis of the fifth moving pair 72. The inner rotation secondary axis of the sixth universal joint 81 in the sixth branch chain 8 is parallel to the third rotation secondary axis 53 , and the inner rotation secondary axis of the sixth universal joint 81 and the third rotation secondary axis 53 are perpendicular to the axis of the sixth movable joint 82 .

[0030] In a preferred embodiment, the outer rotating pairs of the first universal joint 31, the third universal joint 51, the fifth universal joint 71 and the sixth universal joint 81 are respectively connected to the fixed platform 1, and the inner rotating pairs of the first universal joint 31, the third universal joint 51, the fifth universal joint 71 and the sixth universal joint 81 are respectively connected to the lower connecting rod in the corresponding driving rod, the outer rotating pairs of the second universal joint 43 and the fourth universal joint 63 are respectively connected to the moving platform 2, and the inner rotating pairs of the second universal joint 43 and the fourth universal joint 63 are respectively connected to the upper connecting rod in the corresponding driving rod.

[0031] In a preferred embodiment, the axis of the second rotating pair 41 is parallel to the axis of the fourth rotating pair 61, and the fourth rotating pair 61 is parallel to the outer rotating pair axes of the first universal joint 31, the third universal joint 51, the fifth universal joint 71 and the sixth universal joint 81, the center point of the axis of the second rotating pair 41 and the center point of the axis of the fourth rotating pair 61 are all on the same straight line with the geometric center of the fixed platform 1, and the center point of the outer rotating pair axes of the first universal joint 31, the third universal joint 51, the fifth universal joint 71 and the sixth universal joint 81 are all on the same straight line with the geometric center of the fixed platform 1.

[0032] In a preferred embodiment, the axis of the first rotating pair 33 is parallel to the axis of the third rotating pair 53, and the axis of the third rotating pair 53 is parallel to the outer rotating pair axes of the second universal joint 43 and the fourth universal joint 63, the center point of the axis of the first rotating pair 33 and the center point of the axis of the third rotating pair 53 are all on the same straight line with the geometric center of the moving platform 2, and the center point of the outer rotating pair axes of the second universal joint 43 and the fourth universal joint 63 are all on the same straight line with the geometric center of the moving platform 2.

[0033] Specifically, the outer rotational secondary axis of the first universal joint 31 connected to the fixed platform 1, the outer rotational secondary axis of the third universal joint 51, the outer rotational secondary axis of the fifth universal joint 71, and the outer rotational secondary axis of the sixth universal joint 81 are all parallel to the first rotational secondary axis 33 and the third rotational secondary axis 53 connected to the moving platform 2; the inner rotational secondary axis of the first universal joint 31 and the inner rotational secondary axis of the third universal joint 51 connected to the fixed platform 1 are all parallel to the first rotational secondary axis 33 and the third rotational secondary axis 5 connected to the moving platform 2, the outer rotational secondary axis of the second universal joint 43, and the outer rotational secondary axis of the fourth universal joint 63. The outer rotational secondary axis of the second universal joint 43 is collinear with the outer rotational secondary axis of the fourth universal joint 63, and passes through the geometric center point of the moving platform 2. The outer rotational secondary axis of the first universal joint 31 is collinear with the outer rotational secondary axis of the third universal joint 51, and passes through the geometric center point of the fixed platform 1.

[0034] Specifically, the axes of the outer rotating pair of the first universal joint 31, the outer rotating pair of the third universal joint 51, the outer rotating pair of the fifth universal joint 71, the outer rotating pair of the sixth universal joint 81, the second rotating pair 41 and the fourth rotating pair 61 connecting the fixed platform 1 are not in the same plane in space and are perpendicular to the axes of the outer rotating pair of the first rotating pair 33, the third rotating pair 53, the outer rotating pair of the second universal joint 43 and the outer rotating pair of the fourth universal joint 63 connecting the movable platform 2.

[0035] The present invention also includes six driving rods, such as conventional hydraulic devices, pneumatic devices, etc., which respectively drive the first moving pair 32 in the first branch chain 3, the second moving pair 42 in the second branch chain 4, the third moving pair 52 in the third branch chain 5, the fourth moving pair 62 in the fourth branch chain 6, the fifth moving pair 72 in the fifth branch chain 7 and the sixth moving pair 81 in the sixth branch chain 8.

[0036] The present invention has three degrees of freedom, two rotations and one movement. It should be pointed out that when describing the degrees of freedom of the mechanism, rotation and movement are in parallel, not in a sequential relationship. The outer rotation secondary axis of the first universal joint 31 in the first branch chain 3 is collinear with the outer rotation secondary axis of the third universal joint 51 in the third branch chain 5, and the axis passes through the geometric center of the fixed platform 1, and its axis direction is the first rotation direction of the super-redundant drive parallel mechanism, and the outer rotation secondary axis of the second universal joint 43 in the second branch chain 4 is collinear with the outer rotation secondary axis of the fourth universal joint 63 in the fourth branch chain 6, and the axis passes through the geometric center of the moving platform 2, and its axis direction is the second rotation direction of the super-redundant drive parallel mechanism. The direction of the line connecting the geometric center of the fixed platform 1 and the geometric center of the moving platform 2 is the direction of the movement freedom of the super-redundant drive parallel mechanism. By driving the driving rods in each moving branch chain to move, the super-redundant drive parallel mechanism can realize two-dimensional rotation and one-dimensional movement in space. Among them, the first rotation direction and the second rotation direction are always perpendicular to each other in space, and the movement direction is perpendicular to the first rotation direction and the second rotation direction. The position and direction of the first rotation direction are fixed, and the second rotation direction changes with the first rotation direction, that is, the second rotation direction rotates around the first rotation direction.

[0037] In the present invention, when in the initial position, the fixed platform 1 is parallel to the moving platform 2. During the movement of the parallel mechanism, the moving platform 2 has three degrees of freedom, namely, two rotations and one movement. Under the control of the drive system, the moving platform 2 will rotate around the first rotation direction, rotate around the second rotation direction and move along the movement direction. These three degrees of freedom are in parallel and there is no order relationship.

[0038] Specifically, when the fixed platform 1 is parallel to the moving platform 2, the projection of the first rotation pair 33 in the fifth branch chain 7 on the fixed platform 1 is the midpoint of the line between the center point of the outer rotation pair of the first universal joint 31 and the center point of the outer rotation pair of the fifth universal joint 71, and the outer rotation pair axis of the fifth universal joint 71, the outer rotation pair axis of the first universal joint 31 and the outer rotation pair axis of the third universal joint 51 are parallel to each other, and the center point of the outer rotation pair axis of the fifth universal joint 71, the center point of the outer rotation pair axis of the first universal joint 31 and the center point of the outer rotation pair axis of the third universal joint 51 are collinear, and are all on the fixed platform 1. on the diagonal of ; when the fixed platform 1 is parallel to the moving platform 2, the projection of the third rotating pair in the sixth branch chain 8 on the fixed platform 1 is the midpoint of the line between the center point of the outer rotating pair of the third universal joint 51 and the center point of the outer rotating pair of the sixth universal joint 81, and the outer rotating pair axis of the sixth universal joint 81, the outer rotating pair axis of the first universal joint 31 and the outer rotating pair axis of the third universal joint 51 are parallel to each other, and the center point of the outer rotating pair axis of the sixth universal joint 81, the center point of the outer rotating pair axis of the first universal joint 31 and the center point of the outer rotating pair axis of the third universal joint 5 are collinear, and are all on the diagonal of the fixed platform 1.

[0039] In addition to having two continuous rotational freedom axes forming a continuous rotating shaft, the present invention also has three redundant branches. In the case of high-precision, high-rigidity, high-load, high-hardness material processing, it is necessary to introduce redundant drive to improve the performance of the parallel mechanism. There are two main ways to achieve redundant drive of the parallel mechanism: one is to add redundant drive branches to the original mechanism, or replace the original passive joints with active joints; the other is to add constraint branches or joints to the non-redundant full-drive parallel mechanism to reduce the degree of freedom of the original mechanism.

[0040] The present invention has three redundant drive branches. Due to the particularity of the mechanism of the present invention, three branches are redundant branches among the first branch 3, the second branch 4, the third branch 5, the fourth branch 6 and the fifth branch 7. Any three branches among the first branch 3, the second branch 4, the third branch 5, the fourth branch 6 and the fifth branch 7 can be selected as drive branches, and two rotations and one degree of freedom of movement can be achieved. Any four branches among the first branch 3, the second branch 4, the third branch 5, the fourth branch 6 and the fifth branch 7 can also be selected as drive branches, and two rotations and one degree of freedom of movement can still be achieved. The first branch 3, the second branch 4, the third branch 5, the fourth branch 6 and the fifth branch 7 can also be selected as drive branches, and the first branch 3, the second branch 4, the third branch 5, the fourth branch 6, the fifth branch 7 and the sixth branch 86 can also be selected as drive branches, and two rotations and one degree of freedom of movement can still be achieved.

[0041] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A two-rotation-one-movement super-redundant drive parallel mechanism with a composite rotating pair, It is characterized in that It includes a fixed platform, a moving platform and six motion branches arranged between the fixed platform and the moving platform. The fixed platform and the moving platform are both square, and six motion branches are arranged between the fixed platform and the moving platform; The six motion branches include a first branch chain, a second branch chain, a third branch chain, a fourth branch chain, a fifth branch chain and a sixth branch chain, and each of the motion branches includes a driving rod, the first branch chain, the second branch chain, the third branch chain and the fourth branch chain are symmetrically arranged in a square in a counterclockwise direction at the corners of the fixed platform and the moving platform, and the first branch chain and the third branch chain are arranged diagonally, the first branch chain and the third branch chain are both UPR branches, and the lower ends of the driving rods in the first branch chain and the third branch chain are respectively connected to the fixed platform through a first universal joint and a third universal joint, and the upper ends of the driving rods in the first branch chain and the third branch chain are respectively connected to the fixed platform through a first rotation pair and a third rotation pair The moving pair is connected to the moving platform, and the upper connecting rod and the lower connecting rod on the driving rod in the first branch chain and the third branch chain are connected through the first moving pair and the third moving pair respectively, the second branch chain and the fourth branch chain are diagonally arranged, the second branch chain and the fourth branch chain are RPU branches, and the lower ends of the driving rods in the second branch chain and the fourth branch chain are connected to the fixed platform through the second rotating pair and the fourth rotating pair respectively, the upper ends of the driving rods in the second branch chain and the fourth branch chain are connected to the moving platform through the second universal joint and the fourth universal joint respectively, and the upper connecting rod and the lower connecting rod on the driving rod in the second branch chain and the fourth branch chain are connected through the second moving pair and the fourth moving pair respectively; The fifth branch chain and the sixth branch chain are arranged on the diagonal lines of the first branch chain and the third branch chain, the fifth branch chain and the sixth branch chain are both UPR branches, and the lower ends of the driving rods in the fifth branch chain and the sixth branch chain are respectively connected to the fixed platform through the fifth universal joint and the sixth universal joint, the upper ends of the driving rods in the fifth branch chain and the sixth branch chain are respectively connected to the moving platform through the shared first rotation pair and the third rotation pair, and the upper connecting rod and the lower connecting rod on the driving rods in the fifth branch chain and the sixth branch chain are respectively connected through the fifth moving pair and the sixth moving pair; The outer rotation secondary axis of the first universal joint in the first branch chain is collinear with the outer rotation secondary axis of the third universal joint in the third branch chain, and the axis passes through the geometric center of the fixed platform, and its axis direction is the first rotation direction of the super-redundant drive parallel mechanism, and the outer rotation secondary axis of the second universal joint in the second branch chain is collinear with the outer rotation secondary axis of the fourth universal joint in the fourth branch chain, and the axis passes through the geometric center of the moving platform, and its axis direction is the second rotation direction of the super-redundant drive parallel mechanism, and the direction of the line connecting the geometric center of the fixed platform and the geometric center of the moving platform is the direction of the freedom of movement of the super-redundant drive parallel mechanism, and by driving the driving rods in each moving branch chain to move, two-dimensional rotation and one-dimensional movement in the space of the super-redundant drive parallel mechanism can be realized.

2. The two-rotation-one-movement super-redundant drive parallel mechanism with a composite rotating pair according to claim 1, It is characterized in that The inner rotational secondary axis of the first universal joint in the first branch chain is parallel to the first rotational secondary axis, and the inner rotational secondary axis of the first universal joint and the axis of the first rotational secondary are both perpendicular to the first movement secondary axis; The inner rotation secondary axis of the second universal joint in the second branch chain is parallel to the second rotation secondary axis, and the inner rotation secondary axis of the second universal joint and the second rotation secondary axis are both perpendicular to the second movement secondary axis; The inner rotation secondary axis of the third universal joint in the third branch chain is parallel to the third rotation secondary axis, and the inner rotation secondary axis of the third universal joint and the third rotation secondary axis are both perpendicular to the third movement secondary axis; The inner rotation secondary axis of the fourth universal joint in the fourth branch chain is parallel to the fourth rotation secondary axis, and the inner rotation secondary axis of the fourth universal joint and the fourth rotation secondary axis are both perpendicular to the fourth movement secondary axis; The inner rotation secondary axis of the fifth universal joint in the fifth branch chain is parallel to the first rotation secondary axis, and the inner rotation secondary axis of the fifth universal joint and the first rotation secondary axis are both perpendicular to the fifth movement secondary axis; The inner rotation secondary axis of the sixth universal joint in the sixth branch chain is parallel to the third rotation secondary axis, and the inner rotation secondary axis of the sixth universal joint and the third rotation secondary axis are both perpendicular to the sixth movement secondary axis.

3. The two-rotation-one-movement super-redundant drive parallel mechanism with a composite rotating pair according to claim 2, It is characterized in that The outer rotating pairs of the first universal joint, the third universal joint, the fifth universal joint and the sixth universal joint are respectively connected to the fixed platform, and the inner rotating pairs of the first universal joint, the third universal joint, the fifth universal joint and the sixth universal joint are respectively connected to the lower connecting rod in the corresponding driving rod, the outer rotating pairs of the second universal joint and the fourth universal joint are respectively connected to the moving platform, and the inner rotating pairs of the second universal joint and the fourth universal joint are respectively connected to the upper connecting rod in the corresponding driving rod.

4. The two-rotation-one-movement super-redundant drive parallel mechanism with a composite rotating pair according to claim 3, It is characterized in that The second rotation secondary axis is parallel to the fourth rotation secondary axis, and the fourth rotation secondary is parallel to the outer rotation secondary axis of the first universal joint, the third universal joint, the fifth universal joint and the sixth universal joint, the center point of the second rotation secondary axis and the center point of the fourth rotation secondary axis are all on the same straight line with the geometric center of the fixed platform, and the center point of the outer rotation secondary axis of the first universal joint, the third universal joint, the fifth universal joint and the sixth universal joint are all on the same straight line with the geometric center of the fixed platform.

5. The two-rotation-one-movement super-redundant drive parallel mechanism with a composite rotating pair according to claim 4, It is characterized in that The first rotation secondary axis is parallel to the third rotation secondary axis, and the third rotation secondary axis is parallel to the outer rotation secondary axes of the second universal joint and the fourth universal joint, the center point of the first rotation secondary axis, the center point of the third rotation secondary axis and the geometric center of the moving platform are all on the same straight line, and the center point of the outer rotation secondary axes of the second universal joint and the fourth universal joint and the geometric center of the moving platform are all on the same straight line.

6. The two-rotation-one-movement super-redundant drive parallel mechanism with a composite rotating pair according to claim 5, It is characterized in that The outer rotation secondary axis of the first universal joint connected to the fixed platform, the outer rotation secondary axis of the third universal joint, the outer rotation secondary axis of the fifth universal joint and the outer rotation secondary axis of the sixth universal joint are all parallel to the first rotation secondary axis and the third rotation secondary axis connected to the movable platform; The inner rotation secondary axis of the first universal joint connected to the fixed platform and the inner rotation secondary axis of the third universal joint are parallel to the first rotation secondary axis, the third rotation secondary axis, the outer rotation secondary axis of the second universal joint and the outer rotation secondary axis of the fourth universal joint connected to the movable platform; The outer rotation secondary axis of the second universal joint is collinear with the outer rotation secondary axis of the fourth universal joint and passes through the geometric center point of the moving platform; the outer rotation secondary axis of the first universal joint is collinear with the outer rotation secondary axis of the third universal joint and passes through the geometric center point of the fixed platform.

7. The two-rotation-one-movement super-redundant drive parallel mechanism with a composite rotating pair according to claim 1, It is characterized in that When the fixed platform is parallel to the moving platform, the projection of the first rotating pair in the fifth branch chain on the fixed platform is the midpoint of a line between the center point of the outer rotating pair of the first universal joint and the center point of the outer rotating pair of the fifth universal joint, and the outer rotating pair axis of the fifth universal joint, the outer rotating pair axis of the first universal joint and the outer rotating pair axis of the third universal joint are parallel to each other, and the center point of the outer rotating pair axis of the fifth universal joint, the center point of the outer rotating pair axis of the first universal joint and the center point of the outer rotating pair axis of the third universal joint are collinear and are all on the diagonal line of the fixed platform; When the fixed platform is parallel to the moving platform, the projection of the third rotating pair in the sixth branch chain on the fixed platform is the midpoint of a line between a center point of the outer rotating pair of the third universal joint and a center point of the outer rotating pair of the sixth universal joint, and the outer rotating pair axis of the sixth universal joint, the outer rotating pair axis of the first universal joint and the outer rotating pair axis of the third universal joint are parallel to each other, and the center point of the outer rotating pair axis of the sixth universal joint, the center point of the outer rotating pair axis of the first universal joint and the center point of the outer rotating pair axis of the third universal joint are collinear and are all on the diagonal line of the fixed platform.

8. The two-rotation-one-movement super-redundant drive parallel mechanism with a composite rotating pair according to claim 1, It is characterized in that The axes of the outer rotating pair of the first universal joint, the outer rotating pair of the third universal joint, the outer rotating pair of the fifth universal joint, the outer rotating pair of the sixth universal joint, the second rotating pair and the fourth rotating pair connected to the fixed platform are not in the same plane in space and are perpendicular to the axes of the outer rotating pair of the first rotating pair, the third rotating pair, the outer rotating pair of the second universal joint and the fourth universal joint connected to the movable platform.

Images