Two-rotation and one-movement parallel robot mechanism with rotary branch chains

Abstract

According to the two-rotation and one-movement parallel robot mechanism containing the rotary branch chains, on the basis of having a large reachable working space range, the overall size of the mechanism can be reduced, the system complexity is lowered, and the application scene is wider. One rotational degree of freedom can be realized through the three universal pairs and the two revolute pairs II in the rotary branch chain, one rotational degree of freedom can be realized through the revolute pairs II and the three universal pairs in the fixed branch chain, and one movement degree of freedom can be realized through the three revolute pairs II and the three movable pairs, so that the movable platform can realize two-rotation and one-movement movement.

Description

Technical Field

[0001] The invention relates to the technical field of robots, in particular to a two-rotation-one-shift parallel robot mechanism with a rotating branch chain. Background Art

[0002] The two rotation directions of the two-turn-one-shift parallel mechanism are not affected by the movement of the mechanism. In the initial position and the single rotation position, the axes of the two rotation directions are both located on the moving platform. Since the two-turn-one-shift parallel mechanism has good posture adjustment capabilities, it is widely used, and many technicians are committed to studying this type of mechanism. For example, the patent with publication number CN118478345A discloses a PU-type parallel robot mechanism without accompanying motion; it can avoid the accompanying motion of the mechanism by setting a universal joint on the first branch chain and the second branch chain to slide on the circular arc guide rail, so that the parallel mechanism of the present application avoids the occurrence of accompanying motion and improves the motion accuracy of the moving platform. However, in actual use, it is found that the driving pair of the mechanism is a moving pair. When the moving platform moves, the moving pair needs to be based on the guide rail to achieve drive, which makes the entire structure more complicated and not applicable in some scenarios. Summary of the invention

[0003] In order to solve the problem of the relatively complex overall structure of the existing two-rotation and one-shift parallel mechanism based on mobile sub-drive, the present invention provides a two-rotation and one-shift parallel robot mechanism with a rotating branch chain, which can reduce the overall volume of the mechanism and the system complexity on the basis of having a larger reachable working space range, and has a wider range of application scenarios.

[0004] The technical solution of the present invention is as follows: a two-rotation-one-shift parallel robot mechanism with a rotating branch chain, comprising: a moving platform, a base and a unit branch chain, wherein the unit branch chain is arranged between the moving platform and the base; Features: It also includes: a rotating connecting plate and a rotating pair; Each of the unit branch chains comprises: a universal joint, a moving joint and two rotating joints connected in sequence; the universal joint at the top of the unit branch chain is connected to the moving platform; The unit branches are set to 3, one of which is a fixed branch, and the other two unit branches together constitute a rotating branch; The second rotating pair at the bottom end of the fixed branch chain is connected to the base; The rotating connecting plate and the base form the rotating pair 1; the rotating shaft of the rotating pair 1 is perpendicular to the bottom surface of the base; in the rotating branch chain, the rotating shafts of the rotating pairs 2 at the bottom ends of the two unit branches are parallel to each other and are respectively connected to the rotating connecting plate, and the two rotating pairs 2 are symmetrically arranged on both sides of the rotating pair 1; The rotation axis of the second rotation pair at the bottom of each unit branch chain is parallel to the plane where the base is located; The universal joint comprises two rotating shafts which are perpendicular to each other, wherein one of the rotating shafts of the universal joint is parallel to the rotating shaft of the second rotating joint; In the rotating branch chain, the two rotating axes of the universal joints of the two unit branches that are not parallel to the second rotating axes of the rotating joint are collinear; The three rotating pairs are arranged as driving pairs.

[0005] It is further characterized by: The plane formed by the rotating branch chain is perpendicular to the plane where the base is located; The base includes: a rotating branch chain base and a fixed branch chain base, both of which are located on the same plane; The rotating connecting plate is an Ω-shaped structure, wherein the shape of the protruding portion is adapted to the shape of the rotating branch chain base, and is sleeved on the rotating branch chain base to form the rotating pair 1; The moving pair comprises: a sleeve and a sliding rod, the bottom end of the sleeve is connected to the second rotating pair, one end of the sliding rod is inserted from the top end of the sleeve, and the other end is connected to the universal joint.

[0006] The present application provides a two-turn and one-shift parallel robot mechanism containing a rotating branch chain. One rotational degree of freedom can be achieved through three universal joints and two rotating joints 2 in the rotating branch chain, one rotational degree of freedom can be achieved through the rotating joint 2 in the fixed branch chain and three universal joints, and one movement degree of freedom can be achieved through three rotating joints 2 and three moving joints, ensuring that the moving platform can achieve two-turn and one-shift movements. In the technical solution of the present application, the three rotating joints 2 are set as driving joints, and the driving can be achieved without adding other auxiliary structures, which effectively simplifies the complexity of the mechanism and reduces the overall weight of the mechanism. At the same time, the present application introduces a rotating joint 1 in the parallel mechanism whose axis is perpendicular to the plane where the base is located, and sets a rotating branch chain that realizes overall rotation based on the rotating joint 1, thereby avoiding the accompanying movement of the mechanism and improving the movement accuracy. Moreover, the introduction of the rotating branch chain and the rotating joint 1 allows the moving platform to still have two rotations and one shift degree of freedom. Due to the large rotation angle of the rotating branch chain, the rotation angle of the moving platform is increased, making the mechanism more flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a schematic diagram of the overall structure of a two-rotation-one-transfer parallel robot mechanism containing a rotating branch chain in this application; Figure 2 This is an example of the movement posture of the parallel robot mechanism of this application; Figure 3 This is the rotation posture example 1 of the parallel robot mechanism of this application; Figure 4This is Example 2 of the rotational posture of the parallel robot mechanism of this application.

[0008] Among them, 1, first unit branch chain; 11, first rotation pair 2; 12, first translation pair; 13, first universal joint; 14, sleeve; 15, slide rod; 2. Second unit branch chain; 21. Second rotation pair 2; 22. Second translation pair; 23. Second universal joint; 3. The third unit branch chain; 31. The third rotation pair 2; 32. The third translation pair; 33. The third universal joint; 4. Moving platform; 5. Rotating pair 1; 6. Rotating branch chain base; 7. Rotating connecting plate; 8. Fixed branch chain base. DETAILED DESCRIPTION

[0009] like Figure 1~Figure 4 As shown, the present application includes a two-turn-one-shift parallel robot mechanism including a rotating branch chain, which includes: a moving platform 4, a base, a rotating connecting plate 7, a rotating pair 5 and a unit branch chain, and the unit branch chain is arranged between the moving platform 4 and the base.

[0010] In specific implementation, the base can be set as a complete structure or in a split form. In this embodiment, for the convenience of installation, the base is set in a split form. Specifically, the base includes: a rotating branch chain base 6 and a fixed branch chain base 8, both of which are located on the same plane.

[0011] The unit branches in this application are set to 3, specifically: the first unit branch 1, the second unit branch 2, and the third unit branch 3. The three unit branches have the same structure. Each unit branch includes: a universal joint, a moving joint, and a second rotating joint connected in sequence; the universal joint at the top of the unit branch is connected to the moving platform 4. The rotation axis of the second rotating joint at the bottom of each unit branch is parallel to the plane where the base is located.

[0012] like Figure 1 As shown, the structure of the unit branch is described by taking the first unit branch chain 1 as an example. The first unit branch chain 1 comprises: a first universal joint 13, a first moving joint 12 and a first rotating joint 11 arranged from top to bottom. The moving joint and the universal joint are realized based on the structure in the prior art. Figure 1 In the embodiment of the present invention, the first moving pair 12 includes: a sleeve 14 and a slide bar 15, the bottom end of the sleeve 14 is connected to the first rotating pair 11, one end of the slide bar 15 is inserted from the top end of the sleeve 14, and the other end is connected to the first universal joint 13. The rotation axis m4 of the first rotating pair 11 is parallel to the plane where the base is located. The first universal joint 13 is arranged on the bottom end surface of the moving platform 4 through a connecting structure.

[0013] In order to simplify the system structure and eliminate accompanying motion, the present application introduces a revolving pair 1 in which the rotating shaft is perpendicular to the plane where the base is located in the parallel mechanism, and sets a rotating branch chain that realizes overall rotation based on the revolving pair 1. One of the three unit branch chains is used as a fixed branch chain, and the other two unit branch chains together constitute a rotating branch chain.

[0014] In this embodiment, the third unit branch chain 3 is used as a fixed branch chain, and the first unit branch chain 1 and the second unit branch chain 2 together form a rotating branch chain. The third rotation pair 2 32 at the bottom end of the third unit branch chain 3 is connected to the fixed branch chain base 8. The plane formed by the rotating branch chain is perpendicular to the plane where the base is located.

[0015] The rotating connecting plate 7 and the base form a rotating pair 5, and the rotating axis h of the rotating pair 5 is perpendicular to the bottom surface of the base. In this embodiment, the rotating connecting plate 7 is an Ω-shaped structure, in which the shape of the protruding part is adapted to the shape of the rotating branch chain base 6, and is mounted on the rotating branch chain base 6 to form a rotating pair 5, ensuring stable rotation during rotation.

[0016] In the rotating branch chain, the rotating axes of the rotating pair 2 at the bottom of the two unit branches are parallel to each other and are respectively connected to the rotating connecting plate 7, and the two rotating pairs 2 are symmetrically arranged on both sides of the rotating pair 1 5. That is, the first unit branch chain 1 and the second unit branch chain 2 are respectively arranged on the rotating connecting plate 7 symmetrically with the rotating pair 1 5 as the center through the first rotating pair 2 11 and the second rotating pair 2 12 at the bottom. The rotating axis m4 of the first rotating pair 2 11 and the rotating axis m5 of the second rotating pair 2 12 are parallel to each other.

[0017] In the present application, the universal joint at the top of each unit branch chain includes two mutually perpendicular rotation axes, one of which is parallel to the rotation axis of the second rotation pair. In the rotating branch chain, the two rotation axes of the universal joints of the two unit branches that are not parallel to the rotation axis of the second rotation pair are collinear. That is, Figure 4 As shown, the two rotation axes m1 and n1 of the first universal joint 13 are perpendicular to each other, the two rotation axes m1 and n2 of the second universal joint 23 are perpendicular to each other, and the two rotation axes m3 and n3 of the third universal joint 33 are perpendicular to each other. The rotation axis m4 of the first rotation joint 11 and the rotation axis m5 of the second rotation joint 21 are parallel to each other. The rotation axis of the third rotation joint 31 is the rotation axis n4.

[0018] The rotation axes m1, m2, m4 and m5 are parallel to each other. The rotation axes n1 and n2 are collinear, forming a coaxial U. The rotation axes n4 and n3 are parallel to each other.

[0019] In the present application, three rotation pairs 2: the first rotation pair 2 11, the second rotation pair 21 and the third rotation pair 2 31 are set as driving pairs. The three rotation pairs 2 are driven by a motor (not marked in the figure) to achieve rotation. The remaining kinematic pairs are follower pairs and do not need to be driven by a motor.

[0020] by Figure 1 In the initial state, the moving platform 4 is in a horizontal state, and the first unit branch chain 1, the second unit branch chain 2, and the third unit branch chain 3 have the same angle with the horizontal plane. At this time, the plane formed by the rotating branch chain is perpendicular to the plane where the base is located, and the plane where the fixed branch chain is located is perpendicular to the plane where the rotating branch chain is located.

[0021] In this embodiment, the moving platform is a triangle, and the three unit branches are respectively connected to the three vertices of the moving platform. The first rotational pair 11, the first rotational pair 21 and the third rotational pair 31 are of the same height.

[0022] based on Figure 1 In the initial state, the first rotating pair 11, the second rotating pair 21 and the third rotating pair 31 rotate under the drive of the motor. In this embodiment, the three driving pairs rotate synchronously in the direction away from the horizontal plane, the first moving pair 12, the second moving pair 22 and the third moving pair 32 follow, and the moving platform 4 moves upward perpendicular to the horizontal direction to reach Figure 2 When the first rotation pair 11, the second rotation pair 21 and the third rotation pair 31 rotate synchronously in the direction close to the horizontal plane, the movable platform 4 moves downward perpendicular to the horizontal direction. That is, the first moving pair 12, the second moving pair 22 and the third moving pair 32 and the three rotation pairs can achieve one degree of freedom of movement.

[0023] exist Figure 2 On the basis of the third rotational pair 2 31 remaining stationary, the first rotational pair 2 11 and the second rotational pair 21 rotate under the drive of the motor. In this embodiment, the first rotational pair 2 11 moves away from the horizontal plane, the second rotational pair 21 rotates toward the horizontal plane, the first moving pair 12 and the second moving pair 22 follow the movement, and the moving platform 4 rotates in one direction to reach Figure 3 The rotation axis at this time is a rotation axis m3 of the third universal joint 33. Figure 2 Towards Figure 3 That is, the first rotational pair 11, the second rotational pair 21, the first mobile pair 12, the second mobile pair 22 cooperate with the three universal joints to achieve one degree of rotational freedom.

[0024] exist Figure 3On the basis of the first rotating pair 11 and the second rotating pair 21 remain stationary, and the third rotating pair 31 rotates under the drive of the motor. In this embodiment, the third rotating pair 31 rotates in the direction close to the horizontal plane, and the third universal joint 33 rotates in the direction of the horizontal plane, because the angle between the first unit branch chain 1, the second unit branch chain 2 and the base of the fixed branch chain changes, the first mobile pair 12, the second mobile pair 22 and the third mobile pair 32 follow respectively, and at the same time, the rotating pair 5 also follows, and the moving platform 4 produces a rotational motion in the second direction. That is, the third universal joint 33 cooperates with the three universal joints to achieve one degree of rotational freedom.

[0025] After using the technical solution of the present invention, the existing parallel mechanism is improved by adding a pair of rotatable branches, so that the moving platform still has two rotational degrees of freedom and one translational degree of freedom. Moreover, since the rotatable angle of the rotating branch chain is large, the rotation angle of the moving platform is increased, making the mechanism more flexible.

[0026] Therefore, the two-turn-one-shift parallel mechanism in this application has the advantages of the general two-turn-one-shift parallel mechanism, and also avoids the disadvantage of the small accessible working space of some mechanisms; the two rotatable branches are connected, which makes the overall rigidity of the mechanism higher, the movement process smoother, and more adaptable to high-precision working scenes. In addition, the driving pairs in the mechanism of this application are all rotating pairs, which have a simple structure, reduce the overall weight and volume of the mechanism, and avoid occupying too much space.

Claims

1. A two-rotation-one-transfer parallel robot mechanism with a rotating branch chain, comprising: A moving platform, a base and a unit branch chain, wherein the unit branch chain is arranged between the moving platform and the base; Features: It also includes: a rotating connecting plate and a rotating pair; Each of the unit branch chains comprises: a universal joint, a moving joint and two rotating joints connected in sequence; the universal joint at the top of the unit branch chain is connected to the moving platform; The unit branches are set to 3, one of which is a fixed branch, and the other two unit branches together constitute a rotating branch; The second rotating pair at the bottom end of the fixed branch chain is connected to the base; The rotating connecting plate and the base form the rotating pair 1; the rotating shaft of the rotating pair 1 is perpendicular to the bottom surface of the base; in the rotating branch chain, the rotating shafts of the rotating pairs 2 at the bottom ends of the two unit branches are parallel to each other and are respectively connected to the rotating connecting plate, and the two rotating pairs 2 are symmetrically arranged on both sides of the rotating pair 1; The rotation axis of the second rotation pair at the bottom of each unit branch chain is parallel to the plane where the base is located; The universal joint comprises two rotating shafts which are perpendicular to each other, wherein one of the rotating shafts of the universal joint is parallel to the rotating shaft of the second rotating joint; In the rotating branch chain, the two rotating axes of the universal joints of the two unit branches that are not parallel to the second rotating axes of the rotating joint are collinear; The three rotating pairs are arranged as driving pairs.

2. According to claim 1, a two-rotation-one-shift parallel robot mechanism with a rotating branch chain, characterized in that: The plane formed by the rotating branch chain is perpendicular to the plane where the base is located.

3. According to claim 1, a two-rotation-one-shift parallel robot mechanism with a rotating branch chain, characterized in that: The base comprises: a rotating branch chain base and a fixed branch chain base, and the two are located on the same plane.

4. According to claim 1, a two-rotation-one-shift parallel robot mechanism with a rotating branch chain, characterized in that: The rotating connecting plate is an Ω-shaped structure, wherein the shape of the protruding portion is adapted to the shape of the rotating branch chain base, and is sleeved on the rotating branch chain base to form the rotating pair 1.

5. According to claim 1, a two-rotation-one-shift parallel robot mechanism with a rotating branch chain, characterized in that: The mobile pair comprises: A sleeve and a sliding rod, wherein the bottom end of the sleeve is connected to the second rotating pair, one end of the sliding rod is inserted from the top end of the sleeve, and the other end is connected to the universal joint.

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