A four-degree-of-freedom parallel mechanism containing a composite linear module

Abstract

The application discloses a four-degree-of-freedom parallel mechanism containing a composite linear module, which comprises a rack, a movable platform, a first linear module, a first branch chain, a second branch chain and a third branch chain; compared with the prior art, the application has the following advantages: firstly, the three linear modules form a composite linear module to drive the branch chains, and the three branch chains can make the movable platform realize four-degree-of-freedom movement, thereby reducing the number of branch chains, reducing interference and increasing the working space range; secondly, the linear module is used as a moving component, thereby increasing the movement stability and improving the load capacity; finally, the whole mechanism is face-symmetrical, and the two branch chains are completely same, thereby reducing the manufacturing cost.

Description

Technical Field

[0001] This invention belongs to the field of parallel mechanism technology, specifically relating to a four-degree-of-freedom parallel mechanism containing a composite linear module. Background Technology

[0002] When the degree of freedom of a parallel mechanism is greater than three, multiple branches are generally required. However, an excessive number of branches can easily lead to interference and reduce the workspace. Using a composite drive method allows the parallel mechanism to reduce the number of branches while maintaining the required degree of freedom, thus increasing the workspace. In particular, using linear modules for drive can improve the mechanism's load capacity and control accuracy. Therefore, designing a parallel mechanism using composite linear modules for composite drive has significant research value and importance. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide a four-degree-of-freedom parallel mechanism containing a composite linear module.

[0004] To achieve the above objectives, the present invention provides a four-degree-of-freedom parallel mechanism containing a composite linear module, comprising a frame, a moving platform, a first linear module, a first branch I, a second branch II, and a third branch III;

[0005] The frame is horizontally arranged and includes a regular hexagonal frame composed of six straight rods and a connecting rod connecting the diagonals of the frame.

[0006] The moving platform is located above the frame, and a second Hooke hinge support and two ball hinge supports are spaced apart on the bottom surface;

[0007] The first linear module includes a first slide rail, a first slider, a first lead screw, a first motor, a second slide rail, a second slider, a third slide rail, and a third slider. The first slide rail is fixed to one side of the upper surface of the connecting rod on the frame. The second and third slide rails are arranged parallel and symmetrically, and are respectively fixed to the upper surface of two straight rods parallel to the connecting rod on the frame side. The first lead screw is arranged parallel to the first slide rail on one side. The first motor is located outside the outer end of the first slide rail, and its output shaft is connected to one end of the first lead screw. The first slider is connected to the first lead screw through a lead screw nut and is slidably mounted on the first slide rail. The second and third sliders are slidably mounted on the second and third slide rails, respectively. The first slide rail, the first slider, the first lead screw, the first motor, the second slide rail, the second slider 305, the third slide rail, and the third slider constitute a first sliding pair.

[0008] The first branch I and the second branch II have the same structure, both including a second linear module and a first fixed-length rod; the second linear module includes a fourth slide rail, a fourth slider, a second lead screw, a second motor, and a hinged support; wherein, the two ends of the fourth slide rail are respectively fixed to the upper surfaces of the first slider and the second slider; the second lead screw is arranged parallel to the fourth slide rail on one side; the second motor is arranged on the outside of one end of the fourth slide rail, and its output shaft is connected to one end of the second lead screw; the fourth slider is connected to the second lead screw through a lead screw nut, and is slidably mounted on the fourth slide rail, with a hinged support on its upper surface; the fourth slide rail, the fourth slider, the second lead screw, and the second motor constitute a second sliding pair; the lower end of the first fixed-length rod is connected to the hinged support to form a revolute pair, and the upper end is connected to a ball joint support on the moving platform through a ball joint;

[0009] The third branch III includes a third linear module and a second fixed-length rod; the third linear module includes a fifth slide rail, a fifth slider, a third lead screw, a third motor, and a first Hooke hinge support; wherein, the fifth slide rail is fixed on the other side of the upper surface of the connecting rod on the frame and one end coincides with the front end surface of the first slide rail; the third lead screw is set on one side of the fifth slide rail in a parallel manner; the third motor is set on the outer side of the outer end of the fifth slide rail, and its output shaft is connected to one end of the third lead screw; the fifth slider is connected to the third lead screw through the lead screw nut, and is slidably mounted on the fifth slide rail, with a first Hooke hinge support set on its upper surface; the fifth slide rail, the fifth slider, the third lead screw, and the third motor constitute the third sliding pair; the lower end of the second fixed-length rod is connected to the first Hooke hinge support through the first Hooke hinge, and the upper end is connected to the second Hooke hinge support on the moving platform through the second Hooke hinge.

[0010] The second Hooke hinge support and the two ball hinge supports on the moving platform are arranged in a triangular pattern.

[0011] Compared with the prior art, the advantages of the present invention are:

[0012] 1. Three linear modules form a composite linear module drive chain. The three chains enable the moving platform to achieve four degrees of freedom of motion, thereby reducing the number of chains, reducing interference, and increasing the workspace range.

[0013] 2. Using linear modules as moving components increases motion stability and improves load capacity;

[0014] 3. The overall structure is symmetrical, with two identical branches, which can reduce manufacturing costs. Attached Figure Description

[0015] Figure 1 A schematic diagram of the overall structure of the four-degree-of-freedom parallel mechanism containing a composite linear module provided by the present invention;

[0016] Figure 2 A schematic diagram of the frame in the four-degree-of-freedom parallel mechanism containing a composite linear module provided by the present invention;

[0017] Figure 3 A schematic diagram of the moving platform in a four-degree-of-freedom parallel mechanism containing a composite linear module provided by the present invention;

[0018] Figure 4 A schematic diagram of the first linear module in a four-degree-of-freedom parallel mechanism containing a composite linear module provided by the present invention;

[0019] Figure 5 A schematic diagram of the second linear module in a four-degree-of-freedom parallel mechanism containing a composite linear module provided by the present invention;

[0020] Figure 6 A schematic diagram of the first branch in a four-degree-of-freedom parallel mechanism containing a composite linear module provided by the present invention;

[0021] Figure 7 A schematic diagram of the third linear module in a four-degree-of-freedom parallel mechanism containing a composite linear module provided by the present invention;

[0022] Figure 8 A schematic diagram of the third branch in a four-degree-of-freedom parallel mechanism containing a composite linear module provided by the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] like Figure 1 — Figure 8 As shown, the four-degree-of-freedom parallel mechanism containing a composite linear module provided by the present invention includes a frame 1, a moving platform 2, a first linear module 3, a first branch I, a second branch II, and a third branch III;

[0025] The frame 1 is horizontally arranged and includes a regular hexagonal frame composed of six straight rods and a connecting rod connecting the diagonals of the frame.

[0026] The moving platform 2 is located above the frame 1, and a second Hooke hinge support 201 and two ball hinge supports 202 are spaced apart on the bottom surface;

[0027] The first linear module 3 includes a first slide rail 301, a first slider 302, a first lead screw 303, a first motor 12, a second slide rail 304, a second slider 305, a third slide rail 306, and a third slider 307. The first slide rail 301 is fixed to one side of the upper surface of the connecting rod on the frame 1. The second slide rail 304 and the third slide rail 306 are arranged in parallel and symmetrically, and are respectively fixed to the upper surface of two straight rods parallel to the connecting rod on the frame of the frame 1. The first lead screw 303 is arranged parallel to the first slide rail 301 on one side of the first slide rail 301. The first motor 12 is located on the first slide rail 305. The outer side of the outer end of the slide rail 301 is connected to the output shaft and one end of the first lead screw 303; the first slider 302 is connected to the first lead screw 303 through the lead screw nut and is slidably mounted on the first slide rail 301; the second slider 305 and the third slider 307 are slidably mounted on the second slide rail 304 and the third slide rail 306, respectively; the first slide rail 301, the first slider 302, the first lead screw 303, the first motor 12, the second slide rail 304, the second slider 305, the third slide rail 306 and the third slider 307 constitute the first sliding pair 30;

[0028] The first branch I and the second branch II have the same structure, both including a second linear module 4 and a first fixed-length rod 7; the second linear module 4 includes a fourth slide rail 401, a fourth slider 402, a second lead screw 403, a second motor 13, and a hinged support 601; wherein, the two ends of the fourth slide rail 401 are respectively fixed to the upper surfaces of the first slider 302 and the second slider 305; the second lead screw 403 is arranged parallel to the fourth slide rail 401 on one side; the second motor 13 is located outside one end of the fourth slide rail 401. The output shaft is connected to one end of the second lead screw 403; the fourth slider 402 is connected to the second lead screw 403 through the lead screw nut, and is slidably mounted on the fourth slide rail 401, with a hinge support 601 on the upper surface; the fourth slide rail 401, the fourth slider 402, the second lead screw 403 and the second motor 13 constitute the second sliding pair 40; the lower end of the first fixed length rod 7 is connected to the hinge support 601 to form a rotary pair 6, and the upper end is connected to a ball joint support 202 on the moving platform 2 through a ball joint 8;

[0029] The third branch III includes a third linear module 5 and a second fixed-length rod 10; the third linear module 5 includes a fifth slide rail 501, a fifth slider 502, a third lead screw 503, a third motor 14, and a first Hooke hinge support 901; wherein, the fifth slide rail 501 is fixed to the other side of the upper surface of the connecting rod on the frame 1 and one end coincides with the front end surface of the first slide rail 301; the third lead screw 503 is arranged parallel to the fifth slide rail 501 on one side; the third motor 14 is arranged on the outer side of the outer end of the fifth slide rail 501 and outputs... The shaft is connected to one end of the third lead screw 503; the fifth slider 502 is connected to the third lead screw 503 through the lead screw nut, and is also slidably mounted on the fifth slide rail 501, with a first Hooke hinge support 901 on the upper surface; the fifth slide rail 501, the fifth slider 502, the third lead screw 503 and the third motor 14 constitute the third moving pair 50; the lower end of the second fixed length rod 10 is connected to the first Hooke hinge support 901 through the first Hooke hinge 9, and the upper end is connected to the second Hooke hinge support 201 on the moving platform 2 through the second Hooke hinge 11.

[0030] The first branch I and the second branch II share the first linear module 3, and the second linear module 4 and the first linear module 3, as well as the third linear module 5 and the first linear module 3, respectively constitute composite linear modules;

[0031] The second Hooke hinge support 201 and the two ball hinge supports 202 on the moving platform 2 are arranged in a triangular pattern.

[0032] The working principle of the four-degree-of-freedom parallel mechanism containing a composite linear module provided by the present invention is described as follows: The axial direction of the first lead screw 303 is taken as the y-axis, the z-axis is perpendicular to the frame 1 and upwards, and the x-axis conforms to the right-hand rule; the first branch I and the second branch II share the first linear module 3, and the second linear module 4 and the first linear module 3, as well as the third linear module 5 and the first linear module 3, respectively constitute composite linear modules. The four-degree-of-freedom parallel mechanism containing a composite linear module provided by this invention selects the first slide rail 301 on the first linear module 3, the two fourth slide rails 401 on the first branch I and the second branch II, and the fifth slide rail 501 on the third branch III and the corresponding slider as active pairs, which can realize the control of four degrees of freedom of the moving platform 2, namely two rotations and two movements; the first fixed-length rod 7 on the first branch I and the second branch II restricts the degree of freedom of the moving platform 2 to move independently in the x direction, but the moving platform 2 moves along the x-axis when rotating about the y-axis; the rotation axis of the second Hooke hinge support 201 on the moving platform 2 is always parallel to the moving platform 2, and the rotation axes at both ends of the second fixed-length rod 10 are parallel to each other, so the degree of freedom of the moving platform 2 to rotate in the z direction can be constrained; the first slider is fixed. By fixing the first slider 301 and the fourth slider 402, and moving the fifth slider 502, the moving platform 2 can achieve the degree of freedom of rotation in the x-direction; by fixing the first slider 301 and the fifth slider 502, and moving the fourth slider 402, the moving platform 2 can achieve the degree of freedom of rotation in the y-direction; by fixing the fourth slider 402 on the first branch I and the second branch II, and moving the first slider 302 and the fifth slider 502 in the same direction and at equal distances, the moving platform 2 can achieve the degree of freedom of movement in the y-direction; by fixing the first slider 302, and moving the fourth slider 402 on the first branch I and the second branch II, and the fifth slider 502 on the third branch III, simultaneously in the direction of the motor or in the opposite direction, the moving platform 2 can achieve the degree of freedom of movement in the z-direction; ultimately, the moving platform 2 has four degrees of freedom: two rotations and two movements.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A four-degree-of-freedom parallel mechanism comprising a composite linear module, characterized in that: The four-degree-of-freedom parallel mechanism comprising the composite linear module comprises a rack (1), a movable platform (2), a first linear module (3), a first branch chain I, a second branch chain II and a third branch chain III; The rack (1) is horizontally arranged and comprises a regular hexagonal frame formed by six straight rods and a connecting rod connected between opposite corners of the frame; The movable platform (2) is arranged above the rack (1) and is provided with a second Hooke joint support (201) and two spherical joint supports (202) at intervals on the bottom surface; The first linear module (3) comprises a first sliding rail (301), a first sliding block (302), a first lead screw (303), a first motor (12), a second sliding rail (304), a second sliding block (305), a third sliding rail (306) and a third sliding block (307); the first sliding rail (301) is fixed on the upper surface of the connecting rod of the rack (1); the second sliding rail (304) and the third sliding rail (306) are symmetrically arranged in parallel and are respectively fixed on the upper surfaces of two straight rods parallel to the connecting rod of the frame of the rack (1); the first lead screw (303) is arranged in parallel with the first sliding rail (301) on one side of the first sliding rail (301); the first motor (12) is arranged outside the outer end of the first sliding rail (301) and the output shaft is connected with one end of the first lead screw (303); the first sliding block (302) is connected to the first lead screw (303) through a lead screw nut and is slidably mounted on the first sliding rail (301); the second sliding block (305) and the third sliding block (307) are slidably mounted on the second sliding rail (304) and the third sliding rail (306) respectively; the first sliding rail (301), the first sliding block (302), the first lead screw (303), the first motor (12), the second sliding rail (304), the second sliding block (305), the third sliding rail (306) and the third sliding block (307) constitute a first moving pair (30); The first branch chain I and the second branch chain II are identical in structure and each comprises a second linear module (4) and a first fixed-length rod (7); the second linear module (4) comprises a fourth sliding rail (401), a fourth sliding block (402), a second lead screw (403), a second motor (13) and a hinged support (601); wherein the two ends of the fourth sliding rail (401) are fixed on the upper surfaces of the first sliding block (302) and the second sliding block (305) respectively; the second lead screw (403) is arranged in parallel with the fourth sliding rail (401) on one side of the fourth sliding rail (401); the second motor (13) is arranged outside one end of the fourth sliding rail (401) and the output shaft is connected with one end of the second lead screw (403); the fourth sliding block (402) is connected to the second lead screw (403) through a lead screw nut and is installed on the fourth sliding rail (401) in a sliding manner, and the hinged support (601) is arranged on the upper surface; the fourth sliding rail (401), the fourth sliding block (402), the second lead screw (403) and the second motor (13) constitute a second moving pair (40); the lower end of the first fixed-length rod (7) is connected with the hinged support (601) to constitute a rotating pair (6), and the upper end is connected with a spherical hinge support (202) on the moving platform (2) through a spherical hinge (8); The third branch chain III comprises a third linear module (5) and a second fixed-length rod (10); the third linear module (5) comprises a fifth sliding rail (501), a fifth sliding block (502), a third lead screw (503), a third motor (14) and a first hookean hinge support (901); wherein the fifth sliding rail (501) is fixed on the upper surface of the connecting rod on the other side of the rack (1) and one end is coincided with the front end surface of the first sliding rail (301); the third lead screw (503) is arranged in parallel with the fifth sliding rail (501) on one side of the fifth sliding rail (501); the third motor (14) is arranged outside the outer end of the fifth sliding rail (501) and the output shaft is connected with one end of the third lead screw (503); the fifth sliding block (502) is connected with the third lead screw (503) through a lead screw nut and is installed on the fifth sliding rail (501) in a sliding manner, and the first hookean hinge support (901) is arranged on the upper surface; the fifth sliding rail (501), the fifth sliding block (502), the third lead screw (503) and the third motor (14) constitute a third moving pair (50); the lower end of the second fixed-length rod (10) is connected with the first hookean hinge support (901) through a first hookean hinge (9), and the upper end is connected with a second hookean hinge support (201) on the moving platform (2) through a second hookean hinge (11).

2. The four-degree-of-freedom parallel mechanism with a composite linear module according to claim 1, characterized in that: The second hookean hinge support (201) and the two spherical hinge supports (202) on the moving platform (2) are distributed in a triangular shape.

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