CN1745986A - 3- and 4-degree-of-freedom adjustable 3-UPU parallel mechanism experiment platform - Google Patents

Abstract

An experimental platform with adjustable 3-UPU parallel mechanism having 3-4 freedoms features that 3 linearly driven moving sets with same structure are symmetrically arranged on upper platform and base in equilateral triangle mode. Said linearly driven moving set is composed of a linear drive unit and a step motor. Its both ends are respectively linked with a universal joint which consists of a rotary axle connected to said linearly driven moving set to form a rotary set, a supporter connected to said rotary axle to form another rotary set, and a sectorial base. Said supporter is linked to upper platform and base via sectorial base and 4 pins. Its advantages are variable freedom and high moving accuracy.

Description

Experimental Platform for 3-UPU Parallel Mechanism with 3 and 4 Adjustable Degrees of Freedom

technical field

The present invention relates to the field of robots and machinery manufacturing.

Background technique

For the convenience of explanation, use n (n=1, 2, 3, 4, 6) to represent the number of branches, and use S, U, P and R to represent the ball pair, universal joint, moving joint and rotating joint in the branch kinematic chain respectively , and their combination represents a branched kinematic chain structure.

Parallel robots have the characteristics of high structural rigidity, strong bearing capacity, light end mass, small inertia, and no accumulation of position errors. They are complementary to serial robots in application. Compared with the 6-DOF 6-SPS parallel mechanism, the less-DOF parallel mechanism has the advantages of simple structure and easy control. Now, it has become a research hotspot in the field of robotics and manufacturing. In 1983, Hunt proposed the 3-RPS mechanism; in recent years, Tsai’s 3-UPU mechanism has won the US Patent USA No.5656905; Huang Zhen’s three-degree-of-freedom parallel movement mechanism and the precision micro-motion parallel three-dimensional movement mechanism have respectively obtained the Chinese patent CN1311083A , 1539603A. At present, the poses and poses of the motion pairs of various parallel mechanisms with few degrees of freedom are not adjustable, so the kinematic characteristics of each parallel mechanism are single, which is not conducive to experimental research on the characteristics and kinematic characteristics of parallel mechanisms with multiple configurations. The existing theory of parallel mechanism cannot explain the self-motion phenomenon of the three-translational 3-UPU mechanism and other parallel mechanisms with few degrees of freedom, and further theoretical and experimental research is needed.

Contents of the invention

The purpose of the present invention is to provide an adjustable 3-UPU parallel mechanism experiment platform with one machine, multiple types, high motion precision, and 3 and 4 degrees of freedom. The invention has the characteristics of relatively simple mechanism, symmetrical structure, relatively large working space, variable model, adjustable motion sub-pose, variable degrees of freedom, and high motion precision. By adjusting the pose of the universal joint, a variety of new 3-UPU parallel robot mechanism experiment platforms are constructed.

The adjustable 3-UPU parallel mechanism experiment platform with 3 and 4 degrees of freedom is composed of a moving platform 1, a base 2, and three linear drive moving pairs 3 with the same structure connecting the upper platform 1 and the base 2. Its characteristics That is: three linear drive moving pairs 3 with the same structure are symmetrically distributed in an equilateral triangle on the upper platform 1 and the base 2, and there is a linear drive mechanism and a stepping motor 4 in the middle of the said linear drive moving pair 3, and its two ends Connected with the universal pair, the axis of the linear drive moving pair 3 coincides with the center of the universal pair; each universal pair is composed of a rotating shaft 5, a bracket 6 and a fan seat 7, and one end of the linear driving moving pair 3 is connected with the rotating shaft 5 to form a rotation pair, the rotating shaft 5 is connected with the bracket 6 to form another rotating pair, and two mutually orthogonal and vertical rotating pairs form a universal pair, and the bracket 6 is connected to the The upper platform 1 and the base 2 are connected.

The linear drive moving pair 3 is composed of a linear motion drive device or a hydraulic linear motion drive device composed of a stepper motor 4 and a screw pair.

Four fan seat pin holes 14 are processed on the fan seat 7 at 22.5°-45°-67.5°-90° on an arc with the same radius as the center of the fan seat. 4 positioning and rotating connections within the range of °-90°; 8 base holes 15 are processed on the upper platform 1 and the base 2 at an equal radius and equal angle from the center pin 10, and the bottom surface of the fan seat 7 is connected to the upper platform 1 and the base 2 Positioning pins 11 are arranged on the contacting surfaces, and the center pin 10 and positioning pins 11 can realize 8 positioning and rotating connections between the fan seat 7 and the upper platform 1 or base 2 within the range of 0°-360°.

Adjusting the angle of rotation connection of each constraint can change the pose of the gimbal; corresponding to most poses of the gimbal, the degree of freedom of the mechanism is 3, and in another installation pose, the degree of freedom of the mechanism can be changed to 4.

When each rotating shaft 5 connected with the upper platform 1 and the machine base 2 is respectively perpendicular to the upper platform 1 and the machine base 1, the mechanism has 4 degrees of freedom. At this time, the auxiliary motor 13 is connected with a support 6 with a sleeve 12, Drive a linear drive mobile pair 3 to rotate.

Description of drawings

Figure 1. The experimental platform of the adjustable 3-UPU parallel mechanism I with 3 and 4 degrees of freedom;

The universal pair structure and auxiliary driving device of Fig. 2 adjustable 3-UPU parallel mechanism I;

Fig. 3 Experimental platform of the adjustable 3-UPU parallel mechanism II with 3 and 4 degrees of freedom.

In Fig. 1, Fig. 2 and Fig. 3, 1. moving platform, 2. base, 3. driving moving pair, 4. stepping motor, 5. rotating shaft, 6. bracket, 7. fan seat, 8. pin, 9. pin, 10. center pin, 11. positioning pin, 12. cover, 13. auxiliary motor, 14. fan seat pin hole, 15. base pin hole.

Detailed ways

Example 1

Fig. 1 is the first embodiment disclosed by the present invention. The three linear drive branch kinematic chains have the same structure and are symmetrically distributed in an equilateral triangle. Each linear drive branch has a universal pair at both ends and a moving pair 3 in the middle. It coincides with the center of the universal pair, and the moving pair 3 is driven by the stepping motor drive device to realize telescopic movement. Each universal pair is composed of a rotating shaft 5, a bracket 6 and a fan seat 7, the bracket 6 is connected to the fan seat 7 at 0° by pins 8 and 9, and the fan seat 7 is connected to the upper platform by pins 10 and 11. 1 or the base 2 are connected at 0° for positioning and rotation, and each rotating shaft 5 connected with the upper platform 1 and the machine base 2 is kept perpendicular to the upper platform and the machine base respectively. At this time, the mechanism has 4 degrees of freedom, and the sleeve 12 The auxiliary motor 13 is connected with a bracket 6 to drive a linear drive moving pair 3 to rotate.

Example 2

Fig. 3 is the second embodiment disclosed by the present invention, which is different from the first embodiment in that the bracket 6 on the upper platform 1 is connected with the fan base 7 in a 45° rotational positioning by the pin 8 and the pin 9, The bracket 6 on the machine base 2 is connected with the fan base 7 at 90° rotation and positioning by the pin 10 and the pin 11, and the fan base 7 is connected with the upper platform 1 or the base 2 at 0° rotation positioning. The mechanism has 3 free Spend.

There are 3 and 4 adjustable 3-UPU parallel mechanism I and II experimental platforms. In addition to the characteristics of high rigidity and high load capacity of the parallel mechanism, it also has the characteristics of relatively simple mechanism, symmetrical structure, high motion precision and adjustability. Good features. They can be used to design space parallel robots, parallel machine tools, micro robots and sensor elements for various purposes.

Claims (4)

1. An adjustable 3-UPU parallel mechanism experimental platform with 3 and 4 degrees of freedom, the three structures of the moving platform (1), the base (2) and the connecting platform (1) and the base (2) are the same It is composed of linear drive moving pairs (3), which are characterized in that: three linear drive moving pairs (3) with the same structure are symmetrically distributed in an equilateral triangle on the upper platform (1) and base (2), and the said linear drive moving The pair (3) has a linear drive mechanism and a stepping motor (4), the two ends of which are connected to the universal pair, and the axis of the linear drive moving pair (3) coincides with the center of the universal pair; each universal pair consists of a rotating shaft (5), bracket (6) and fan seat (7), one end of the linear drive moving pair (3) is connected with the rotating shaft (5) to form a rotating pair, and the rotating shaft (5) is connected to the bracket (6) to form another rotating pair , two mutually orthogonal and perpendicular rotating pairs constitute the universal pair, and the bracket (6) connects with the upper The platform (1) is connected with the base (2). 2. degree of freedom according to claim 1 is 3 and 4 adjustable 3-UPU parallel mechanism experiment platform, it is characterized in that: linear drive mobile pair (3) is made up of stepper motor (4) and screw pair to move linearly Drive device or hydraulic linear movement drive device. 3. degree of freedom according to claim 1 and 2 is 3 and 4 adjustable 3-UPU parallel mechanism experiment platform, it is characterized in that: on fan base (7) at 22.5 °-45 °-67.5 °-90 ° and 4 pin holes (14) are processed on the center of the fan seat on an equal radius arc, and the bracket (6) and the fan seat (7) are realized by pins (8) and pins (9) and 4 positioning rotations within the range of 0°-90° Connection; 8 positioning holes (15) are processed on the upper platform (1) and the base (2) at the same radius and equal angle from the center pin (10), and the bottom surface of the fan seat (7) is connected with the upper platform (1) and the base (2) Positioning pins (11) are set on the contacting surfaces, and the center pin (10) and positioning pins (11) can realize the 0°-360° between the fan base (7) and the upper platform (1) or base (2). 8 positioning and rotating connections within the ° range. 4. degree of freedom according to claim 3 is 3 and 4 adjustable 3-UPU parallel mechanism experiment platform, it is characterized in that: when each rotating shaft (5) that is connected with upper platform (1) and support (2) When they are perpendicular to the upper platform (1) and machine base (2), the mechanism has 4 degrees of freedom. At this time, the auxiliary motor (13) is connected with a bracket (6) with a sleeve (12) to drive a linear drive to move Vice (3) rotates.

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