CN101704244B - 2-RRT&RRS 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 rotating joints and connecting rods from top to bottom, wherein the connecting rods are arranged among the hooke joint and the two rotating joints; and the other branched chain comprises a ball joint, two rotating joints and connecting rods from top to bottom, wherein the connecting rods are arranged among the ball joint and the two rotating 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 at high speed, can be designed.

Description

2-RRT&RRS 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 object of the present invention is to overcome the deficiencies of the prior art, and 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 respectively composed of a Hooke from top to bottom. Hinges T1, T2, two rotary hinges R1, R2, R4, R5 and connecting rods L1, L2, L4, L5 between them; branch chain M3 consists of a ball hinge S1, two rotary hinges from top to bottom Composed of R3, R6 and the connecting rod L3, L6 between them; where:

Said motion platform (1) and fixed platform (2) are similar isosceles right triangles;

Said rods L4, L5, and L6 are respectively connected to the fixed platform through rotary hinges R4, R5, and R6. The axis of rotation of R6 is perpendicular to the axes of rotation of hinges R4 and R5;

Said rods L1, L2, L3 are respectively connected with the rods L4, L5, L6 through the rotary hinges R1, R2, R3, and the axis of the rotary hinge R1 is parallel to the axis of the rotary hinge R4, and the axis of the rotary hinge R2 is parallel to the axis of the rotary hinge R2. The axes of the rotary hinge R5 are parallel, and the axes of the rotary hinge R3 are parallel to the axes of the rotary hinge R6;

Said rods L1, L2, L3 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 parallel to the axes of the rotary hinges R1 and R2 respectively, and one axis of the ball hinge S1 is parallel to the axis of the rotary hinge R3;

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 rotating hinge R4 and the central point of the rotating hinge R6 is perpendicular to the connecting line between the central point of the rotating hinge R5 and the central point of the rotating hinge R6. 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 mechanism has few joints, and the kinematic pairs are all low. The total number of degrees of freedom of the kinematic 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

【Description of drawings】

Figure 12 - Schematic diagram of the RRT&RRS three-degree-of-freedom space parallel robot mechanism. 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 space-parallel robot mechanism with one translation and two rotations realized by using fewer kinematic pairs and all of them are low. 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 respectively composed of a Hooke from top to bottom. Hinges T1, T2, two rotating hinges R1, R2, R4, R5 and connecting rods L1, L2, L4, L5 between them; the branch chain M3 is respectively rotated by a ball hinge S1 and 1 from top to bottom Hinge R3, R6 and connecting rod L3 between them, L6 form. The connecting rods L4, L5, L6 and the rotating hinges R4, R5, R6 of the fixed platform 2 are the driving pairs of the mechanism, and the axes of the rotating hinges R1, R2, R3 adjacent to the driving pair are respectively parallel to the axis of the driving pair, passing through Hooke The hinges T1, T2 and the ball hinge S1 connect the rods L1, L2, L3 to the motion platform 1, and the two axes of the Hooke hinge T1, T2 are coplanar with the motion platform 1, and one of the axes is the same as the rotary hinge R1, R2 is parallel to the axis, and one axis of the ball hinge S1 is parallel to the axis of the rotary hinge R3. The moving platform 1 and the fixed platform 2 are similar triangles, and are isosceles right-angled triangles. The line connecting the Hooke hinge T1 and the center point of the ball hinge S1 is perpendicular to the line connecting the Hooke hinge T2 and the center point of the ball hinge S1; the rotating hinge R4 The connection line with the central point of the rotary hinge R6 is perpendicular to the connection line between the rotary hinge R5 and the central point of the rotary hinge R6. the

As shown in Figure 1, the rotating hinges connected to the fixed platform are R4, R5, and R6 are driving pairs, which are driven by motors. When the driving pairs move different corners under the control, the other rotating pairs, Hooke hinges, and ball hinges will move correspondingly 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 three-freedom degree spatial parallel robot mechanism is characterized in that three side chains of this mechanism by motion platform (1), fixed platform (2) and above-mentioned two platforms of connection: side chain M1, side chain M2, side chain M3 composition; Side chain M1 wherein, side chain M2 be from top to bottom respectively by a Hooke's hinge T1, T2, two rotating hinge R1, and R2, R4, R5 and the connecting rod L1 between them, L2, L4, L5 forms; Side chain M3 is from top to bottom respectively by a spherical hinge S1, two rotating hinge R3, R6 and the connecting rod L3 between them, and L6 forms; Wherein:

Said motion platform (1) is similar isosceles right triangle with fixed platform (2);

Said rod member L4, L5, L6 pass through rotating hinge R4 respectively, R5, and R6 and fixed platform link, and rotating hinge R4, R5, R6 are that mechanism drives pair, and rotating hinge R4, and the pivot center of R5 is parallel, the pivot center of rotating hinge R6 and rotating hinge R4, the pivot center of R5 is vertical;

Said rod member L1, L2, L3 pass through rotating hinge R1, R2 respectively, R3 and rod member L4, L5, L6 links, and the axis of rotating hinge R1 is parallel with the axis of rotating hinge R4, and the axis of rotating hinge R2 is parallel with the axis of rotating hinge R5, and the axis of rotating hinge R3 is parallel with the axis of rotating hinge R6;

Said rod member L1, L2, L3 is respectively by Hooke's hinge T1, T2 and spherical hinge S1 and motion platform (1) link, Hooke's hinge T1, the axis of two axles on the T2 and motion platform (1) coplane, and one of them axis respectively with rotating hinge R1, the axis of R2 is parallel, and the axis of spherical hinge S1 is parallel with the axis of rotating hinge R3;

Hooke's hinge T1 central point is vertical with the line of spherical hinge S1 central point with Hooke's hinge T2 central point with the line of spherical hinge S1 central point; Rotating hinge R4 central point is vertical with the line of rotating hinge R6 central point with rotating hinge R5 central point with the line of rotating hinge R6 central point.

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