CN105856204A - Holohedral symmetry parallel robot for machining complex curved surface - Google Patents

Abstract

The invention relates to a fully symmetrical parallel robot for processing complex curved surfaces. The purpose is to provide a parallel mechanism that has the advantages of good isotropy, high rigidity, high precision, simple structure, easy processing and assembly, and easy control. The technical solution is: a fully symmetrical parallel mechanism, characterized in that it includes a moving platform, a frame and three branch mechanisms connected between the frame and the moving platform, wherein the first branch, the second branch and the third branch are all Distributed on the rack and arranged in equal intervals of 120° to each other.

Description

A Fully Symmetrical Parallel Robot for Complex Surface Machining

technical field

The invention relates to the technical field of numerical control machine tools, in particular to a fully symmetrical parallel robot.

Background technique

Parallel mechanism (PM) can be defined as a closed-loop mechanism in which the moving platform (end effector) and the fixed platform (frame) are connected through at least two independent kinematic chains and driven in parallel. If the parallel mechanism satisfies the following four conditions: a. It can realize stable and continuous multi-degree-of-freedom motion; b. The kinematic chain structure of each branch is the same; c. All branches are symmetrically arranged on the fixed platform; d. The driver is installed on the branch The position is the same; then the mechanism is called a fully-symmetrical parallel mechanism (fully-symmetrical PM). Compared with the general parallel mechanism, the fully symmetrical parallel mechanism not only has the traditional advantages of high stiffness, high precision, high speed, flexibility, and easy integration, but also has better isotropy, that is, better motion transmission characteristics, force transfer and dynamic properties. Therefore, fully symmetrical parallel mechanisms are widely used in industry, medical treatment, food and other industries. The specific application fields involve positioning devices, micro-manipulators, motion simulators, machining center spindle heads, multi-axis CNC machine tools, etc.

In the practical application of complex curved surface processing, multi-degree-of-freedom parallel mechanisms are not required. In order to effectively simplify calculations, control and reduce manufacturing costs, parallel mechanisms with few degrees of freedom that can achieve corresponding operations have been developed. Among them, the two-transition-one-shift parallel mechanism is an important type of parallel mechanism with few degrees of freedom, and it is a type with great engineering application value in parallel mechanisms with few degrees of freedom.

There are now three-degree-of-freedom invention patents (such as CN101844307B, CN205033197U, CN104625198A), whose branch chains are relatively complex and not completely symmetrical, so there is no symmetry in the kinematic performance and dynamic performance of the mechanism, and isotropy cannot be guaranteed. Therefore, it is necessary to propose a two-rotation-one-shift fully symmetrical parallel mechanism with simple and compact structure, easy processing and assembly, high rigidity, high precision, low price, good isotropy, and can meet the needs of complex curved surface processing.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the shortcomings of the background technology and provide a fully symmetrical parallel mechanism for processing complex curved surfaces. The parallel mechanism should have good isotropy, high rigidity, high precision, simple structure, and Easy to assemble and easy to control.

The technical scheme provided by the invention is:

A fully symmetrical parallel mechanism, characterized in that it includes a moving platform, a frame, and three branch mechanisms connected between the frame and the moving platform, wherein the first branch, the second branch and the third branch are all distributed on the frame And they are arranged equally at 120°;

The first branch, the second branch and the third branch respectively include a moving pair, a ball joint, a connecting rod, and a rotating pair connected between the frame and the moving platform, including a guide rod and a slide block; the first branch . The secondary axes of movement in the second branch and the third branch are evenly distributed around the symmetrical centers of the three guide rods and are equally spaced at 120° to each other;

the second branch is collinear with the axis of the revolving pair in the third branch and perpendicular to the axis of the revolving pair in the first branch; or,

The axes of the first branch, the second branch and the third branch are coplanar and intersect at the center of the moving platform, and the angle between them is 120°; or,

The axes of rotation pairs in the first branch, the second branch and the third branch are coplanar and intersect at one point in space.

The driving mechanism of the parallel mechanism includes a ball screw mechanism driving the moving pair and a servo motor driving the ball screw mechanism.

The secondary axes of movement in the first branch, the second branch and the third branch are all parallel to each other.

A cutter head is installed on the moving platform.

The beneficial effects of the present invention are:

The invention can realize two degrees of freedom of rotation and one degree of freedom of movement in space, has the advantages of good isotropy, high processing precision, high rigidity, simple structure, easy processing and assembly, and easy control, etc., and can meet the requirements of complex curved surface processing Work requirements.

Description of drawings

Fig. 1 is a three-dimensional structural diagram of Embodiment 1 of the present invention.

Fig. 2 is a schematic diagram of the three-dimensional structure of Embodiment 2 of the present invention.

Fig. 3 is a schematic perspective view of the third embodiment of the present invention.

detailed description

The present invention will be further described below in conjunction with the embodiments shown in the accompanying drawings, but the present invention is not limited to the following embodiments.

Example 1

As shown in Figure 1: a fully symmetrical parallel mechanism for processing complex curved surfaces, including a frame 11, a moving platform 4, a cutter head 5, and three branches connecting the frame and the moving platform (for the PSR type moving support Chain); where the tool head for processing is fixed on the moving platform; the first branch, the second branch and the third branch are all distributed on the frame and arranged in 120° equal divisions between each other; the first branch, the second branch The two branches and the third branch respectively include a moving pair 1P connected between the frame 11 and the moving platform (including a guide rod 15 fixed on the frame 11 and a slider 12 slidingly matched with the guide rod), and a ball joint 1S. , connecting rod 13, revolving pair 1R; the moving sub-axis (parallel to the length direction of the guide rod) in the first branch, the second branch and the third branch is evenly distributed around the center of symmetry of the three guide rods and mutually Arranged in 120° equal divisions; the second branch is collinear with the secondary axis of rotation in the third branch, and the secondary axis of rotation in the first branch is perpendicular to the secondary axis of rotation in the second branch and the third branch; the rotation of each branch Minor axis is nothing but the spherical center of branch spherical hinge respectively.

In this embodiment, the driving pair is a moving pair on each branch, and the driving method is a ball screw mechanism (omitted in the figure) driven by a servo motor; when the driving pair moves, the mechanism performs two rotations and one shift with 3 degrees of freedom.

Example 2

As shown in Figure 2: a fully symmetrical parallel mechanism for processing complex curved surfaces, including a frame 11, a moving platform 4, a cutter head 5, and three branches connecting the frame and the moving platform (for the PSR type moving support Chain); where the tool head for processing is fixed on the moving platform; the first branch, the second branch and the third branch are all distributed on the frame and arranged in 120° equal divisions between each other; the first branch, the second branch The two branches and the third branch respectively include a moving pair 1P (including a guide rod 15 fixed on the frame 11 and a sliding block 12)) connected between the frame 11 and the moving platform, and a ball joint in sequence. 1S, connecting rod 13, rotating pair 1R; the moving secondary axes (parallel to the length direction of the guide rods) in the first branch, the second branch and the third branch are evenly distributed around the symmetrical centers of the three guide rods and mutually The first branch, the second branch and the third branch are coplanar and intersect at the center of the moving platform, and the angle between them is 120°; the rotation of each branch Minor axis is nothing but the spherical center of branch spherical hinge respectively.

In this embodiment, the driving pair is a moving pair on each branch, and the driving method is a ball screw mechanism (omitted in the figure) driven by a servo motor; when the driving pair moves, the mechanism performs two rotations and one shift with 3 degrees of freedom.

Example 3

As shown in Figure 3: a fully symmetrical parallel mechanism for processing complex curved surfaces, including a frame 11, a moving platform 4, a cutter head 5, and three branches connecting the frame and the moving platform (for the PSR type moving support Chain); where the tool head for processing is fixed on the moving platform; the first branch, the second branch and the third branch are all distributed on the frame and arranged in 120° equal divisions between each other; the first branch, the second branch The two branches and the third branch respectively include a moving pair 1P (including a guide rod 15 fixed on the frame 11 and a sliding block 12)) connected between the frame 11 and the moving platform, and a ball joint in sequence. 1S, connecting rod 13, rotating pair 1R; the moving secondary axes (parallel to the length direction of the guide rods) in the first branch, the second branch and the third branch are evenly distributed around the symmetrical centers of the three guide rods and mutually 120° between them are equally divided; the secondary axes of rotation in the first branch, the second branch and the third branch are coplanar and intersect at point O in space; the secondary axes of rotation of the branches are no more than the respective branches The center of the spherical hinge.

In this embodiment, the driving pair is a moving pair on each branch, and the driving method is a ball screw mechanism (omitted in the figure) driven by a servo motor; when the driving pair moves, the mechanism performs two rotations and one shift with 3 degrees of freedom.

Claims (4)

1. a fully symmetrical parallel mechanism is characterized in that: comprise moving platform (4), frame (11) and be connected to three branch mechanism between frame and moving platform, wherein the first branch, the second branch and The third branches are evenly distributed on the rack and are arranged equally at 120° between each other; The first branch, the second branch and the third branch respectively respectively include a moving pair (1P) and a ball joint (1S) connected between the frame and the moving platform, which include a guide rod (15) and a slider (12). , connecting rod (13), rotating pair (1R); the moving sub-axes in the first branch, the second branch and the third branch are all around the center of symmetry of the three guide rods and are 120° to each other, etc. sub-arrangement; the second branch is collinear with the axis of the revolving pair in the third branch and perpendicular to the axis of the revolving pair in the first branch; or, The axes of the first branch, the second branch and the third branch are coplanar and intersect at the center of the moving platform, and the angle between them is 120°; or, The axes of rotation pairs in the first branch, the second branch and the third branch are coplanar and intersect at one point in space. 2. The fully symmetrical parallel mechanism according to claim 1, wherein the driving mechanism of the parallel mechanism includes a ball screw mechanism driving the moving pair and a servo motor driving the ball screw mechanism. 3. The fully symmetrical parallel mechanism according to claim 2, characterized in that: the secondary moving axes of the first branch, the second branch and the third branch are all parallel to each other. 4. The fully symmetrical parallel mechanism according to claim 3, characterized in that: a cutter head (5) is installed on the moving platform.