CN101704243B - 2-PPT&PPS three-degree-of-freedom space parallel robot mechanism - Google Patents

Abstract

The invention discloses a spatial parallel robotic mechanism with three degrees of freedom (DOF). The mechanism consists of a motion platform, a fixed platform and three branched chains for linking the two platforms; two of the three branched chains have the same structure and respectively comprise a hooke joint, two prismatic joints and connecting rods from top to bottom, wherein the connecting rods are arranged among the hooke joint and the prismatic joints; and the other branched chain comprises a ball joint, two prismatic joints and connecting rods from top to bottom, wherein the connecting rods are arranged among the ball joint and the two prismatic joints. A working platform of the mechanism can realize motion output with one translational DOF and two rotations; and the mechanism has less joints and a motion pair only has 13 DOFs in total, thereby effectively solving the problem that a parallel mechanism is easy to bend, reverse and deform due to overabundance of DOFs of the motion pair. In addition, a rotating head with two DOFs is connected in series to the motion platform, and therefore, a hybrid robot with five DOFs, which can be used in occasions of machining complex curved surfaces, can be designed.

Description

2-PPT&PPS three-degree-of-freedom space parallel robot mechanism

【Technical field】

The invention relates to the technical field of robots and advanced manufacturing, in particular to a parallel robot mechanism with few degrees of freedom that realizes space-translation and two-rotation. the

【Background technique】

The parallel robot mechanism can be defined as: the upper and lower platforms (fixed platform and moving platform) are connected by two or more kinematic branch chains, each kinematic branch chain is composed of connecting rods and kinematic pairs, and the kinematic platform has two or more A mechanism with more than two degrees of freedom driven in parallel. Parallel robot mechanisms are widely used in technical fields such as large-scale analog equipment, robots, CNC machine tools, sensors, micro-manipulators, engraving machines, and measuring machines. The Stewart platform is a typical parallel robot mechanism, which has 6 degrees of freedom. It was first used in parallel robots and CNC machine tools. parallel mechanism. the

Due to structural limitations, many technical problems of the 6-DOF parallel mechanism have not been well resolved, such as strong kinematic coupling, complex kinematics solutions, small working space, and poor transmission characteristics. Parallel robot mechanisms with few degrees of freedom have broad application prospects in industrial production. Many scholars have studied a variety of mechanisms of this type, such as Delta mechanisms and Star Like mechanisms. Chinese scholars have also achieved a large number of research results in the research of parallel robot mechanisms with few degrees of freedom (such as patent application numbers: 01108297.6; 01113519.0; 03113354.1; 200410018623.8; 200510037951.7, etc.). the

At present, a 5-degree-of-freedom hybrid robot is constructed by connecting a 2-degree-of-freedom rotating head in series based on a 3-degree-of-freedom parallel robot mechanism as a positioning component, which has broad application prospects in the field of high-speed processing. The positioning components in the form of parallel structure have the problem of insufficient rigidity due to too many rods and too many kinematic pairs. It is necessary to create a new model that meets the requirements of the kinematic form and has fewer kinematic pairs and high rigidity. the

【Content of invention】

The purpose of the present invention is to provide a space parallel robot mechanism with simple structure, few kinematic pairs, low cost and realizing one translation and two rotations. the

The solution adopted by the present invention to solve the above-mentioned problems is to design a spatial parallel robot mechanism that realizes one translation and two rotations by using fewer kinematic pairs. The mechanism consists of a moving platform 1, a fixed platform 2, and three branch chains connecting the above two platforms: branch chain M1, branch chain M2, and branch chain M3; the branch chain M1 and branch chain M2 are composed of a Hooke from top to bottom. Hinges T1, T2, two moving hinges P1, P4, P2, P5 and connecting rods L1, L2, L3, L4 between them; branch chain M3 consists of a ball hinge S1, two moving hinges from top to bottom Composed of P3, P6 and the connecting rod L5, L6 between them; where:

The moving platform 1 and the fixed platform 2 are similar isosceles right-angled triangles; said rods L2, L4, L6 are respectively connected with the fixed platform through the movable hinges P4, P5, P6, and the movable hinges P4, P5, P6 are three parts of the mechanism. drive pairs, and the movement axes of rods L2, L4, L6 are perpendicular to the fixed platform;

Said rods L1, L3, L5 are respectively connected with rods L2, L4, L6 through movable hinges P1, P2, P3, and the axis of movable hinge P1 is perpendicular to the axis of movable hinge P4, and the axis of movable hinge P2 It is perpendicular to the axis of the movable hinge P5, and the axis of the movable hinge P3 is perpendicular to the axis of the movable hinge P6;

Said rods L1, L3, L5 are respectively connected with the motion platform 1 through the Hooke hinge T1, T2 and the ball hinge S1, the axes of the two shafts on the Hooke hinge T1, T2 are coplanar with the motion platform 1, and One of the axes is perpendicular to the axes of the movable hinges P1 and P2 respectively, and one axis of the ball hinge S1 is perpendicular to the axis of the movable hinge P3;

The moving platform 1 and the fixed platform 2 are similar triangles, and are isosceles right-angled triangles, and satisfy: The connecting line of the central point is vertical; the connecting line between the central point of the movable hinge P4 and the central point of the movable hinge P6 is perpendicular to the connecting line between the central point of the movable hinge P5 and the central point of the movable hinge P6. the

The beneficial effects of the present invention are:

1. The working platform of the mechanism can realize the motion output of one translation and two rotations. the

2. The mechanism is simple, the motion pairs are all low, the mechanism joints are few, and the total number of degrees of freedom of the motion pairs is only 13. the

3. It can effectively improve the problem that the parallel mechanism is prone to deflection and torsional deformation caused by too much freedom of kinematic pairs. the

4. By connecting a two-degree-of-freedom rotating head in series on the motion platform, a five-degree-of-freedom hybrid robot can be designed, which can be used in complex curved surfaces and other occasions. the

5. Long-distance movement can be realized in the translational direction, especially suitable for long-axis curved surface processing. the

【Description of drawings】

Figure 12 - Schematic diagram of the three-degree-of-freedom space parallel robot mechanism of PPT&PPS. the

The following will be described in detail in conjunction with the embodiments of the present invention with reference to the accompanying drawings. the

【Detailed ways】

Example 1

A spatial parallel robot mechanism with one translation and two rotations realized by using fewer kinematic pairs. The mechanism consists of a moving platform 1, a fixed platform 2, and three branch chains connecting the above two platforms: branch chain M1, branch chain M2, and branch chain M3; the branch chain M1 and branch chain M2 are composed of a Hooke from top to bottom. Hinges T1, T2, two movable hinges P1, P4, P2, P5 and connecting rods L1, L2, L3, L4 between them; branch chain M3 consists of a ball hinge S1, two movable hinges from top to bottom P3, P6 and the link L5 between them, L6 composition. The connecting rods L2, L4, L6 are connected with the fixed platform 2, the movable hinges P4, P5, P6 are the driving pair of the mechanism, and the axes of the movable hinges P1, P2, P3 adjacent to the driving pair are respectively perpendicular to the axis of the driving pair, passing through the tiger Hooke hinges T1, T2 and ball hinge S1 connect the rods L1, L3, L5 to the moving platform 1, and the two axes of the Hooke hinges T1, T2 are coplanar with the moving platform 1, and one of the axes is in the same plane as the moving hinge P1 , the P2 axis is perpendicular, and one axis of the ball hinge S1 is perpendicular to the axis of the movable hinge P3. The moving platform 1 and the fixed platform 2 are similar triangles, and are isosceles right triangles. The line connecting the center point of Hooke hinge T1 and the center point of ball hinge S1 is perpendicular to the line connecting the center point of Hooke hinge T2 and the center point of ball hinge S1 ; The connecting line between the central point of the movable hinge P4 and the central point of the movable hinge P6 is perpendicular to the connecting line between the central point of the movable hinge P5 and the central point of the movable hinge P6. the

As shown in Figure 1, the movable hinges P4, P5, and P6 connected to the fixed platform are the driving pairs, which are driven by the motor to drive the ball screw. When each driving pair moves different displacements under the control, the other moving pairs, Hooke hinges, and ball hinges make corresponding movements under the pull of the connecting rod and the moving platform, so that the moving platform can be leveled in the working space. Move two turn movement. the

Claims (1)

1. A 2-PPT&PPS three-degree-of-freedom space parallel robot mechanism is characterized in that the mechanism consists of a motion platform (1), a fixed platform (2) and three branch chains connecting the above two platforms: branch chain M1 and branch chain M2 , branch chain M3; the branch chain M1 and the branch chain M2 are respectively composed of a Hooke hinge T1, T2, two moving hinges P1, P4, P2, P5 and connecting rods L1, L2 between them from top to bottom. Composed of L3 and L4; the branch chain M3 is composed of a ball hinge S1, two movable hinges P3, P6 and connecting rods L5 and L6 between them from top to bottom; among them: the moving platform (1) and the fixed platform (2 ) is a similar isosceles right triangle; The connecting rods L2, L4, L6 are respectively connected to the fixed platform through the movable hinges P4, P5, P6. The movable hinges P4, P5, P6 are the three driving pairs of the mechanism, and the movement axes of the rods L2, L4, L6 are in line with the fixed platform. The platforms are perpendicular to each other; The rods L1, L3, L5 are respectively connected to the rods L2, L4, L6 through the movable hinges P1, P2, P3, and the axis of the movable hinge P1 is perpendicular to the axis of the movable hinge P4, and the axis of the movable hinge P2 is perpendicular to the axis of the movable hinge The axis of P5 is vertical, and the axis of moving hinge P3 is perpendicular to the axis of moving hinge P6; The rods L1, L3, L5 are respectively connected to the motion platform (1) through the Hooke hinges T1, T2 and the ball hinge S1, the axes of the two axes on the Hooke hinges T1, T2 are coplanar with the motion platform (1), And one of the axes is perpendicular to the axes of the movable hinges P1 and P2 respectively, and one axis of the ball hinge S1 is perpendicular to the axis of the movable hinge P3; The line connecting the center point of Hooke hinge T1 and the center point of ball hinge S1 is perpendicular to the line connecting the center point of Hooke hinge T2 and the center point of ball hinge S1; the line connecting the center point of moving hinge P4 and the center point of moving hinge P6 is perpendicular to the line connecting The line connecting the center point of P5 and the center point of movable hinge P6 is perpendicular.

Images