CN105666471A - SPS+UPU+(2RPS+R) type four-freedom-degree parallel robot - Google Patents

Abstract

Provided is an SPS+UPU+(2RPS+R) type four-freedom-degree parallel robot. The robot comprises a base, a movable platform, an SPS type support chain, an RPR type support chain, two RPS type support chains of the identical structure, a connecting rod and two T type shafts. The middle of the connecting rod is rotationally connected with the middle of the base, the two ends of the connecting rod are rotationally connected with the lower ends of the two RPS type support chains, and the upper ends of the two RPS type support chains are connected with ball pairs of the movable platform. The SPS type support chain and the RPR type support chain are symmetrically arranged on the two sides of the connecting rod, the two ends of the SPS type support chain are connected with the base and another ball pair of the movable platform, and the two ends of the RPR type support chain are connected with the movable platform and a universal pair of the base through the two T type shafts. The movable platform has the four-freedom-degree kinetic characteristic, and four freedom degrees comprise three horizontal-moving freedom degrees and one freedom degree of rotation around the connecting rod. The SPS+UPU+(2RPS+R) type four-freedom-degree parallel robot is simple in structure; the working space for the position and the gesture of the movable platform is large, flexibility is good, precision is high, bearing capacity is high, and control is easy.

Description

A SPS+UPU+(2RPS+R) type four-degree-of-freedom parallel robot

technical field

The invention belongs to the field of robots, in particular to a parallel robot.

Background technique

For the convenience of illustration, let S, U, P and R denote the ball joint, the universal joint, the moving joint and the rotating joint respectively. In the past 20 years, the four-degree-of-freedom parallel mechanism has been a hot spot and frontier in the field of robotics research at home and abroad. At present, some four-degree-of-freedom parallel mechanisms have been successfully used in the manufacture of parallel machine tools, medical equipment, micro-electromechanical equipment, multi-dimensional force parallel sensors, etc. The Chinese authorized invention patents related to the four-degree-of-freedom parallel robot mechanism found in recent years are as follows: the patent with the publication number CN100586666 discloses a four-degree-of-freedom parallel mechanism with three-dimensional movement and one rotation; the patent with the publication number CN100553899 publishes A bifurcated four-degree-of-freedom parallel robot mechanism with four PRPU branches; the patent publication number CN1170658C discloses a four-degree-of-freedom parallel robot mechanism with two UPS branches and two RPS branches; the publication number is The patent of CN100411826C discloses a four-degree-of-freedom parallel robot mechanism with two-dimensional translation and two-dimensional rotation, which has 2 intersecting PUU branches and 2 non-fork PUU branches; Branch four-degree-of-freedom parallel robot mechanism, with 4 SPS branches and 1 SP passive branch; the patent with publication number CN102601793B announced a new type of space fully symmetrical four-degree-of-freedom parallel mechanism, with 4 PSS branches and 1 intermediate passive branch; The patent with the publication number CN102601794B discloses a high-rigidity four-degree-of-freedom parallel mechanism with attitude adjustment capability, which has four PRUP-type branches, and the first driving movement pair of each branch is connected to the machine base. The first movement pair is used for Attitude adjustment; the patent publication number CN100513062 discloses a four-degree-of-freedom parallel mechanism with 2 UPS-type branches and 2 UPR-type branches; the patent publication number CN1211185C discloses a virtual axis CNC machine tool and robot The four-degree-of-freedom parallel mechanism with two translations and two rotations has three pairs of rods on its moving platform, and four pairs of rods on its base.

To sum up, the above-mentioned four-DOF parallel mechanisms have their own characteristics. Among the existing three-shift-one-rotation parallel mechanisms, the rotation of the moving platform is basically the rotation around the base or the normal line of the moving platform. The follow-up platform twists around the base or the normal line of the moving platform. When the torsion angle is large, the moving branch chains are likely to interfere with each other, reducing the actual working space and reducing the stiffness of the parallel mechanism, thereby obtaining limited mechanical benefits. The translational motion of the existing four-degree-of-freedom parallel mechanism platform is different in each direction, and the translational work space is limited. How to construct a four-degree-of-freedom parallel robot with simple structure, large working space and flexible movement, improve its rigidity, and obtain greater mechanical benefits has always been a meaningful and continuous effort in the field of robotics.

Contents of the invention

The purpose of the present invention is to provide a SPS+UPU+(2RPS+R) type four-freedom system with simple structure, large working space for the position and attitude of the moving platform, good flexibility, the same translational performance in any direction, and strong ability to withstand large changes in load parallel robot. The moving platform of the present invention has four-degree-of-freedom motion characteristics of three-translational motion and four-degree-of-freedom rotation relative to the machine base.

The invention includes a machine base, a moving platform, a connecting rod, two RPS branch chains with the same structure, an SPS branch chain, an RPR branch chain and two T-shaped shafts with the same structure.

The machine base is a rectangular plate, and an open slot is arranged on the rectangular machine base, and a through hole A is provided on the side wall of the open slot; a horizontal through hole B is provided in the middle of the machine base, and a ball is arranged in the center of the rear side of the machine base. Auxiliary support, the moving platform is provided with an open slot corresponding to the base, a through hole C is provided on the side wall of the open slot, and three ball auxiliary supports are provided on the moving platform, the through hole C and The three spherical sub-supports are evenly distributed on the same circumference;

The SPS type branch chain is a mobile electric cylinder, and its two ends are connected with the ball pair support of the machine base and the moving platform through a ball pair;

The connecting rod passes through the through hole B in the middle of the machine base, and the two ends of the connecting rod are respectively provided with through holes, the through holes are parallel to each other and perpendicular to the connecting rod, and shafts are arranged in the through holes; the two RPS type The branch chain is a mobile electric cylinder, one end of which is connected to the ball sub-support of the moving platform through a ball pair, and the other end is connected to the shaft in the through hole of the connecting rod to form a rotating pair, which is perpendicular to the moving electric cylinder;

The T-shaft is composed of a major axis and a minor axis. The minor axis is arranged at one end of the major axis and is perpendicular to the major axis. A is rotatably connected with the through hole C of the opening groove of the moving platform; the RPR type branch chain is a mobile electric cylinder, and its two ends are rotatably connected with the short shafts of the above-mentioned T-shaft I and T-shaft II.

Compared with the prior art, the present invention has the following advantages:

1. The moving platform has the characteristics of three-translation and rotation around the connecting rod relative to the machine base. It has the advantages of large working space, good flexibility, and isotropic translation.

2. The moving platform is a plane-symmetrical parallel mechanism with four pairs of rods and the machine base is three pairs of rods, which is essentially different from the existing four-degree-of-freedom parallel mechanism.

3. The overall structure is symmetrical and simple, and all branch chains are straight branch chains, with large bearing capacity and high rigidity.

Description of drawings

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

In the figure: 1-machine base, 2-moving platform, 3-RPS type branch chain, 4-RPR type branch chain, 5-SPS type branch chain, 6-connecting rod, 7-T type shaft I, 8-T type Axis II.

detailed description

In the schematic diagram of the SPS+UPU+(2RPS+R) type four-degree-of-freedom parallel robot shown in Figure 1, the base 1 is a rectangular plate with an open slot on the rectangular base and a through-hole Hole A; the middle part of the machine base is provided with a bump on both sides, and a through hole B parallel to the above through hole A is arranged on the bump, and a ball auxiliary support is arranged in the center of the rear side of the base, and the moving platform 2 There is an open slot corresponding to the machine base, and a through hole C is provided on the side wall of the open slot. There are also three ball sub-supports on the moving platform, and the through hole C and the three ball sub-supports are evenly distributed. On the same circle; the SPS type branch chain 5 is a mobile electric cylinder, and its two ends are connected with the ball pair support of the machine base and the moving platform through a ball pair; the connecting rod 6 passes through the through hole B on the bump of the machine base, and the The two ends of the connecting rod are respectively provided with through holes, the through holes are parallel to each other and perpendicular to the connecting rod, and the through holes are equipped with shafts; the two RPS type branch chains 3 with the same structure are mobile electric cylinders, one end of which is connected to the connecting rod through the ball pair. The ball pair support of the moving platform is connected, and the other end is connected with the shaft in the through hole of the above-mentioned connecting rod to form a rotating pair, which is perpendicular to the mobile electric cylinder; the T-shaft I7 and T-shaft II8 with the same structure are composed of the long axis and the T-shaft II8. The short axis is set at one end of the long axis and is perpendicular to the long axis. One end of the long axis of T-shaft I and T-shaft II is respectively connected with the through hole A of the opening slot of the machine base and the through hole of the opening slot of the moving platform. C rotation connection; the RPR type branch chain 4 is a mobile electric cylinder, and its two ends are respectively connected with the short axis of the above-mentioned T-shaped shaft I and T-shaped shaft II.

Claims (1)

1. A SPS+UPU+(2RPS+R) type four-degree-of-freedom parallel robot is characterized in that: it comprises a support, a moving platform, a connecting rod, two structurally identical RPS type branch chains, SPS type branch chains, RPR type branch chain and two T-shaped shafts with the same structure; the base is a rectangular plate with an open slot on the rectangular base, and a through hole A is provided on the side wall of the open slot; the middle part of the base is equipped with a horizontal Through hole B, a ball auxiliary support is provided at the center of the rear side of the base, an opening slot corresponding to the machine base is provided on the moving platform, and a through hole C is provided on the side wall of the opening slot. There are also three ball sub-supports, the through hole C and the three ball sub-supports are evenly distributed on the same circumference; the SPS type branch chain is a mobile electric cylinder, and its two ends pass through the ball pair and the base and the moving platform. The ball auxiliary support is connected; the connecting rod passes through the through hole B in the middle of the machine base, and the two ends of the connecting rod are respectively provided with through holes, the through holes are parallel to each other and perpendicular to the connecting rod, and the through holes are equipped with shafts; The two RPS type branch chains are mobile electric cylinders, one end of which is connected with the ball support of the moving platform through a ball pair, and the other end is connected with the shaft in the through hole of the above-mentioned connecting rod to form a rotating pair, which is perpendicular to the moving Electric cylinder; the T-shaped shaft is composed of a long shaft and a short shaft, and the short shaft is set at one end of the long shaft and is perpendicular to the long shaft; one end of the long shaft of the T-shaped shaft I is rotatably connected with the through hole A of the opening groove of the machine base, One end of the long axis of the T-shaft II is rotatably connected with the through hole C of the opening groove of the moving platform; the RPR type branch chain is a mobile electric cylinder, and its two ends rotate with the short axes of the above-mentioned T-shaft I and T-shaft II respectively. connect.