A partially decoupled two-rotation two-movement parallel mechanism

Abstract

The present invention belongs to the field of robot technology. The purpose is to provide a partially decoupled two-rotation two-movement parallel mechanism, which can achieve partial decoupling, reduce the mutual influence between different movements, and has the characteristics of low manufacturing cost, simple assembly, flexible control, strong load-bearing capacity, high precision and rigidity, and good isotropy. The technical solution is: a partially decoupled two-rotation two-movement parallel mechanism, characterized in that: the parallel mechanism includes a frame, a first moving platform and a second moving platform connected by a fifth rotating pair, a first branch and a second branch connected in parallel between the frame and the first moving platform, and a third branch and a fourth branch connected in parallel between the frame and the second moving platform; the four branches have the same structure.

Description

Technical Field

[0001] The invention belongs to the technical field of robots, and in particular is a partially decoupled two-rotation and two-movement parallel mechanism. Background Art

[0002] The parallel mechanism is a multi-loop closed chain with multiple degrees of freedom in space. Its main feature is that the moving platform is connected in parallel with the frame through two or more branches. The parallel mechanism has good structural rigidity, high flexibility, large load-bearing capacity and high position accuracy. Because of its outstanding advantages, the parallel mechanism has an important position in the field of robots. Specifically, the parallel mechanism has many applications in robot welding, robot spraying, parallel manipulators, etc., and has good application prospects.

[0003] A two-rotational and two-movement parallel mechanism refers to a mechanism that can output two rotational motions and two movement motions at the end, with a total of four degrees of freedom, usually requiring four branches and four drives (such as the invention patent with publication number CN208826619U). Generally speaking, the output motions of the parallel mechanism are mutually coupled. Even the motion in a single degree of freedom direction requires all drives to move together, which makes the kinematic model and control of the mechanism difficult. A motion-decoupled parallel mechanism refers to a mechanism in which certain degrees of freedom do not require all drive joints to move in coordination. A mechanism with this feature has unique advantages in kinematic modeling and control. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a partially decoupled two-rotating and two-moving parallel mechanism, which can achieve partial decoupling and reduce the mutual influence between different movements. It has the characteristics of low manufacturing cost, simple assembly, flexible control, strong load-bearing capacity, high precision and rigidity, and good isotropy.

[0005] The technical solution provided by the present invention is:

[0006] A partially decoupled two-rotating and two-moving parallel mechanism, characterized in that: the parallel mechanism includes a frame, a first moving platform and a second moving platform connected by a fifth rotating pair, a first branch and a second branch connected in parallel between the frame and the first moving platform, and a third branch and a fourth branch connected in parallel between the frame and the second moving platform; the four branches have the same structure.

[0007] The first branch includes a first connecting rod and a second connecting rod that form a closed loop with the frame; a first moving pair and a first rotating pair are sequentially connected between the frame and the first connecting rod; a second moving pair and a second rotating pair are sequentially connected between the frame and the second connecting rod; the first connecting rod and the second connecting rod are connected to the first moving platform through a first branch T-shaped hinge, and the first branch T-shaped hinge is hinged to the hinge shaft of the first connecting rod and hinged to the second connecting rod at the same time;

[0008] The first branch T-hinge is hinged to the axis of the hinge shaft of the first moving platform, and is perpendicular to the axis of the hinge shaft of the first branch T-hinge hinged to the first connecting rod; the moving axis of the first moving pair is parallel to the moving axis of the second moving pair; the rotation axis of the first rotating pair is perpendicular to the moving axis of the first moving pair, and is parallel to the rotation axis of the second rotating pair and parallel to the axis of the hinge shaft of the first branch T-hinge hinged to the first connecting rod.

[0009] The first branch T-hinge is hinged to the axis of the hinge shaft of the first moving platform, and coincides with the axis of the hinge shaft of the second branch T-hinge hinged to the first moving platform; the third branch T-hinge is hinged to the axis of the hinge shaft of the second moving platform, and coincides with the axis of the hinge shaft of the fourth branch T-hinge hinged to the second moving platform; the rotation axis of the fifth rotating pair is parallel to the axis of the hinge shaft of the first branch T-hinge hinged to the first moving platform.

[0010] The first movable pair includes a first guide rail fixedly connected to the frame and a first slider slidably matched with the first guide rail; the second movable pair includes a second guide rail fixedly connected to the frame and a second slider slidably matched with the second guide rail.

[0011] The first guide rail and the second guide rail are both arranged perpendicular to the horizontal plane.

[0012] The axes of the first rotation pairs and the second rotation pairs on the four branches are parallel.

[0013] The first movable pair and the second movable pair are both drive pairs; the drive mechanisms of the first movable pair and the second movable pair are both ball screw mechanisms driven by motors.

[0014] The beneficial effects of the present invention are:

[0015] The present invention can realize two rotational motions and two translation motions of two moving platforms in space, and has the advantages of low manufacturing cost, simple assembly, easy control, high rigidity, good isotropy, etc. It can be widely used in robot welding, robot spraying, parallel manipulators and other fields, and has good market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention.

[0017] Figure 2 It is a schematic diagram of the three-dimensional structure of the first branch.

[0018] Reference numerals:

[0019] 2. The first moving platform; 3. The second moving platform; 11. The frame; 12. The first slider; 13. The second slider; 14. The first connecting rod; 15. The second connecting rod; 16. The first branch T-hinge; R1. The first rotation pair; R2. The second rotation pair; R3. The first branch T-hinge is hinged to the hinge axis of the first connecting rod; R4. The first branch T-hinge is hinged to the hinge axis of the first moving platform; R5. The fifth rotation pair; R6. The third branch T-hinge is hinged to the hinge axis of the second moving platform; R7. The second branch T-hinge is hinged to the hinge axis of the first moving platform; R8. The fourth branch T-hinge is hinged to the hinge axis of the second moving platform. DETAILED DESCRIPTION

[0020] The following is a further description with reference to the embodiments shown in the accompanying drawings.

[0021] The partially decoupled two-rotating and two-moving parallel mechanism as shown in the figure includes a frame 11, a first moving platform 2, a second moving platform 3 and four branches (i.e., a first branch, a second branch, a third branch and a fourth branch). The first moving platform and the second moving platform are both flat plate structures; the first moving platform and the second moving platform are connected by a fifth rotating pair R5. The first branch and the second branch are connected in parallel between the frame and the first moving platform. The third branch and the fourth branch are connected in parallel between the frame and the second moving platform. In this embodiment, the first moving platform and the second moving platform have the same structure, the four branches have the same structure, and the four branches are symmetrically connected to the two moving platforms. During operation, the actuator (not shown in the figure) is fixed on the first moving platform and / or the second moving platform.

[0022] The structure of the first branch is as follows:

[0023] The first branch includes a first connecting rod 14 and a second connecting rod 15 that form a closed loop with the frame. A first moving pair and a first rotating pair R1 are sequentially connected between the frame and the first connecting rod; a second moving pair and a second rotating pair R2 are sequentially connected between the frame and the second connecting rod; the first moving pair includes a first guide rail (not shown) fixedly connected to the frame and a first slider 12 that slides with the first guide rail; the second moving pair includes a second guide rail (not shown) fixedly connected to the frame and a second slider 13 that slides with the second guide rail. Preferably, the first guide rail and the second guide rail are arranged perpendicular to the horizontal plane.

[0024] The moving axis of the first movable pair is parallel to the moving axis of the second movable pair (both are arranged perpendicular to the horizontal plane); the rotation axis of the first rotating pair is perpendicular to the moving axis of the first movable pair (that is, the rotation axis of the first rotating pair is arranged horizontally); the rotation axis of the first rotating pair is parallel to the rotation axis of the second rotating pair.

[0025] The first connecting rod, the second connecting rod and the first moving platform are integrally connected via a first branch T-shaped hinge 16 (each T-shaped hinge is provided with two hinge axes which are perpendicular and intersecting to each other); wherein, the T-shaped hinge is hinged to the hinge axis R3 of the first connecting rod and is also hinged to the second connecting rod; the axis of the hinge axis of the T-shaped hinge hinged to the first connecting rod is parallel to the rotation axis of the first rotating pair R1; the axis of the hinge axis R4 of the T-shaped hinge hinged to the first moving platform is perpendicular to the axis of the hinge axis R3 of the T-shaped hinge hinged to the first connecting rod.

[0026] The structures of the remaining branches (the second branch, the third branch and the fourth branch) (including their own structures and external connection structures) are the same as the above-mentioned structure of the first branch and will not be described in detail.

[0027] The first branch T-hinge is hinged to the axis R4 of the articulation axis of the first moving platform, and coincides with the axis R7 of the articulation axis of the second branch T-hinge hinged to the first moving platform; the third branch T-hinge is hinged to the axis R6 of the second moving platform, and coincides with the axis R8 of the articulation axis of the fourth branch T-hinge hinged to the second moving platform; the rotation axis of the fifth rotation pair R5 is parallel to the axis R4 of the articulation axis of the T-hinge hinged to the first moving platform.

[0028] The axes of the first rotating pair and the second rotating pair on the four branches are parallel, and the first moving pair and the second moving pair are both driving pairs. Preferably, the driving mechanisms of the first moving pair and the second moving pair are both ball screw mechanisms driven by motors (not shown in the figure). When the driving pair moves, the first moving platform and the second moving platform can perform two rotations and two movements with four degrees of freedom.

[0029] Finally, it should be noted that the above examples are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and many variations are possible. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A partially decoupled two-rotating and two-moving parallel mechanism, characterized in that: The parallel mechanism comprises a frame (11), a first moving platform (2) and a second moving platform (3) connected via a fifth rotating pair (R5), a first branch and a second branch connected in parallel between the frame and the first moving platform, and a third branch and a fourth branch connected in parallel between the frame and the second moving platform; the four branches have the same structure; The first branch comprises a first connecting rod (14) and a second connecting rod (15) forming a closed loop with the frame; a first moving pair and a first rotating pair (R1) are connected in sequence between the frame and the first connecting rod; a second moving pair and a second rotating pair (R2) are connected in sequence between the frame and the second connecting rod; the first connecting rod and the second connecting rod are connected to the first moving platform via a first branch T-shaped hinge (16); the first branch T-shaped hinge is hinged to the hinge shaft (R3) of the first connecting rod and is also hinged to the second connecting rod; The axis of the hinge shaft (R4) of the first branch T-shaped hinge hinged to the first moving platform is perpendicular to the axis of the hinge shaft (R3) of the first branch T-shaped hinge hinged to the first connecting rod; the moving axis of the first moving pair is parallel to the moving axis of the second moving pair; the rotation axis of the first rotating pair is perpendicular to the moving axis of the first moving pair, and is parallel to the rotation axis of the second rotating pair and to the axis of the hinge shaft of the first branch T-shaped hinge hinged to the first connecting rod; The axis of the hinge shaft (R4) of the first branch T-hinge hinged to the first moving platform coincides with the axis of the hinge shaft (R7) of the second branch T-hinge hinged to the first moving platform; the axis of the hinge shaft (R6) of the third branch T-hinge hinged to the second moving platform coincides with the axis of the hinge shaft (R8) of the fourth branch T-hinge hinged to the second moving platform; the rotation axis of the fifth rotating pair (R5) is parallel to the axis of the hinge shaft (R4) of the first branch T-hinge hinged to the first moving platform.

2. The partially decoupled two-rotation and two-motion parallel mechanism according to claim 1, characterized in that: The first movable pair comprises a first guide rail fixedly connected to the frame and a first slide block (12) slidably engaged with the first guide rail; the second movable pair comprises a second guide rail fixedly connected to the frame and a second slide block (13) slidably engaged with the second guide rail.

3. The partially decoupled two-rotation and two-motion parallel mechanism according to claim 2, characterized in that: The first guide rail and the second guide rail are both arranged perpendicular to the horizontal plane.

4. The partially decoupled two-rotation two-movement parallel mechanism according to claim 3, characterized in that: The axes of the first rotation pairs and the second rotation pairs on the four branches are parallel.

5. The partially decoupled two-rotation two-movement parallel mechanism according to claim 4, characterized in that: The first movable pair and the second movable pair are both drive pairs; the drive mechanisms of the first movable pair and the second movable pair are both ball screw mechanisms driven by motors.

Images