Motion redundancy 3-PRPS parallel mechanism with symmetrical structure

Abstract

The utility model relates to the technical field of robots, in particular to a motion redundancy 3-PRPS parallel mechanism with a symmetrical structure, which comprises a fixed platform, a movable platform with an electric spindle and branch chains connected between the fixed platform and the movable platform, and the branch chains comprise a first branch chain, a second branch chain and a third branch chain. The first branch chain, the second branch chain and the third branch chain are of the same structure and are evenly distributed in the circumferential direction of the movable platform at intervals of 120 degrees, one end of each branch chain is connected with the movable platform, and the other end of each branch chain is connected with a fixed platform. The method can be used for machining and grinding large aviation structural parts.

Description

Technical Field

[0001] The utility model relates to the technical field of robots, and specifically relates to a structurally symmetrical motion redundant 3-PRPS parallel mechanism. Background Art

[0002] Compared with the serial mechanism, the parallel mechanism has significant advantages in stiffness, precision, speed, and dynamic performance. Therefore, it has been widely used in industrial production, such as handling and palletizing, motion simulation, surgical medical treatment, parts processing, etc. The six-degree-of-freedom parallel mechanism has a complex structure and is difficult to control, so it is difficult to be applied in many engineering projects. The parallel mechanism with fewer degrees of freedom has the advantages of simple structure, low design and manufacturing costs, etc., especially the parallel mechanism with two rotations and one shift of the dynamic platform output motion, which has broad application prospects in the fields of complex parts processing and product sorting.

[0003] Hybrid machine tools are an important high-end equipment, a processing equipment for complex parts, and a high-end equipment support for China's transition from a "manufacturing power" to a "manufacturing powerhouse". At present, most of the hybrid machine tools put into use on the market are based on a two-turn-one-shift parallel mechanism, a typical example of which is Germany's Ecospeed equipment. The equipment consists of a Z3 parallel spindle head (3-PRS) and a two-degree-of-freedom mobile frame. The serial part of the hybrid machine tool uses industrial standard parts, and the core is actually a parallel mechanism for tool posture adjustment. However, some of the currently proposed two-turn-one-shift parallel mechanisms, such as the Z3 spindle head, do not have redundant degrees of freedom in motion, and the tool workspace and rotation angle are small, and the flexibility is insufficient, making it difficult to achieve high-speed and high-precision processing and grinding of some complex parts. Therefore, based on the 3-PRS parallel mechanism, it is urgent to expand and design a motion redundant two-turn-one-shift parallel mechanism. Utility Model Content

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a 3-PRPS parallel mechanism with symmetrical motion redundancy.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a structurally symmetrical motion redundant 3-PRPS parallel mechanism, comprising a fixed platform, a moving platform with an electric spindle, and a branch chain connected between the fixed platform and the moving platform, the branch chain comprising a first branch chain, a second branch chain and a third branch chain, the first branch chain, the second branch chain and the third branch chain have the same structure and are evenly distributed at an interval of 120° along the circumferential direction of the moving platform, one end of each branch chain is connected to the moving platform, and the other end is connected to a certain platform.

[0006] In some of the embodiments, the three branches each include a first movable pair, a rotating pair, a second movable pair and a ball pair. The first movable pair is arranged on a fixed platform, the rotating pair is arranged on the first movable pair and connected to the second movable pair, and the ball pair is arranged on the second movable pair and connected to the fixed platform.

[0007] In some embodiments, the first moving pair includes a slider, a guide rail and a screw, the guide rail is installed on a fixed platform, the slider is slidably installed on the guide rail, the screw is installed on the fixed platform, and the screw matches the slider.

[0008] In some embodiments, the second moving pair is a hydraulic cylinder, one end of the hydraulic cylinder is rotatably connected to the slider, and the other end of the hydraulic cylinder is provided with a ball pair.

[0009] In some of the embodiments, the first moving pair and the second moving pair of the three branches are parallel and perpendicular to the rotating pair, and the connection points of each branch chain with the fixed platform and the moving platform respectively form an equilateral triangle.

[0010] Compared with the prior art, the beneficial effects of the utility model are: the parallel mechanism proposed in this application has the characteristics of motion redundancy, the output motion of the moving platform is still two rotations and one movement, and it has the advantages of high speed, high precision, high rigidity, large rotation angle, high flexibility, etc., and can be used for the processing and grinding of large aviation structural parts.

[0011] Details of one or more embodiments of the present application are presented in the following drawings and descriptions to make other features, purposes and advantages of the present application more concise and easy to understand. The present application is fully described and understood through the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the utility model;

[0013] Figure 2 This is a schematic diagram of the first branch chain structure of the utility model;

[0014] Figure 3 It is a schematic diagram of the structure of the dynamic platform of the utility model.

[0015] In the figure: 1, fixed platform; 2, first branch chain, 21, slider; 22, guide rail; 23, inner rod of telescopic lever; 24, outer rod of telescopic cylinder; 25, ball pair; 3, second branch chain; 4, third branch chain; 5, moving platform; 6, electric spindle. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0017] See also Figure 1-3 The utility model provides a technical solution: a structurally symmetrical motion redundant 3-PRPS parallel mechanism, comprising a fixed platform, a moving platform with an electric spindle, and a branch chain connected between the fixed platform and the moving platform, the branch chain comprising a first branch chain, a second branch chain and a third branch chain, the first branch chain, the second branch chain and the third branch chain have the same structure and are evenly distributed at an interval of 120° along the circumferential direction of the moving platform, one end of each branch chain is connected to the moving platform, and the other end is connected to a certain platform.

[0018] The three branches all include a first movable pair, a rotating pair, a second movable pair and a ball pair. The first movable pair is arranged on a fixed platform, the rotating pair is arranged on the first movable pair and connected to the second movable pair, and the ball pair is arranged on the second movable pair and connected to the fixed platform.

[0019] The moving auxiliary drive mode can be selected by ball screw or hydraulic drive, and the rotating auxiliary drive mode can be selected by servo motor drive.

[0020] The first moving pair comprises a slider, a guide rail and a screw, wherein the guide rail is mounted on a fixed platform, the slider is slidably mounted on the guide rail, the screw is mounted on the fixed platform, and the screw matches the slider.

[0021] A servo motor is arranged at the end of the screw rod, and the screw rod is driven to rotate by the servo motor, and the linkage slider moves on the guide rail, so that the slider moves on the fixed platform.

[0022] The second moving pair is a hydraulic cylinder, one end of which is rotatably connected to the slider, and the other end of which is provided with a ball pair, through which the hydraulic cylinder is connected to the moving platform, and the hydraulic cylinder includes a telescopic lever inner rod and a telescopic lever outer rod which cooperate with each other;

[0023] A through hole is arranged on the sliding block and cooperates with the rotating shaft on the inner rod of the telescopic lever to form a first rotating pair.

[0024] The first moving pair and the second moving pair of the three branches are parallel and perpendicular to the rotating pair, and the connection points of each branch chain with the fixed platform and the moving platform respectively form an equilateral triangle.

[0025] Through this technical solution, from the beginning, by controlling the movement of the six drive pairs, the three branches of the mechanism can generate redundant degrees of freedom of motion, reduce input singular configurations, increase the rotation angle of the moving platform, and improve the flexibility of the mechanism. The motion redundant 3-PRPS parallel mechanism used for processing large aviation structural parts should have the advantages of high stiffness accuracy, good flexibility, fast processing speed, large working space, simple kinematics, and easy control.

[0026] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

[0027] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A symmetrical kinematically redundant 3-PRPS parallel mechanism, characterized in that: It includes a fixed platform, a moving platform with an electric spindle, and a branch chain connected between the fixed platform and the moving platform. The branch chain includes a first branch chain, a second branch chain and a third branch chain. The first branch chain, the second branch chain and the third branch chain have the same structure and are evenly distributed with an interval of 120° along the circumferential direction of the moving platform. One end of each branch chain is connected to the moving platform, and the other end is connected to a certain platform. The three branch chains each include a first moving pair, a rotating pair, a second moving pair and a ball pair. The first moving pair is arranged on the fixed platform, the rotating pair is arranged on the first moving pair and is connected to the second moving pair, and the ball pair is arranged on the second moving pair and is connected to the fixed platform.

2. The structurally symmetrical kinematically redundant 3-PRPS parallel mechanism according to claim 1, characterized in that: The first moving pair comprises a slider, a guide rail and a screw, wherein the guide rail is mounted on a fixed platform, the slider is slidably mounted on the guide rail, the screw is mounted on the fixed platform, and the screw matches the slider.

3. The structurally symmetrical kinematically redundant 3-PRPS parallel mechanism according to claim 1, characterized in that: The second moving pair is a hydraulic cylinder, one end of which is rotatably connected to the sliding block, and the other end of which is provided with a ball pair.

4. The structurally symmetrical kinematically redundant 3-PRPS parallel mechanism according to claim 1, characterized in that: The first moving pair and the second moving pair of the three branches are parallel and perpendicular to the rotating pair, and the connection points of each branch chain with the fixed platform and the moving platform respectively form an equilateral triangle.

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