A four-degree-of-freedom parallel mechanism with two independently constrained branches

Abstract

The present invention discloses a four-degree-of-freedom parallel mechanism with two independent constraint branches, comprising a base, a driver, a constraint branch, and a moving platform. The base comprises a bottom plate, four first articulated supports, and two second articulated supports. The four first articulated supports are evenly arranged at the four corners of the upper portion of the bottom plate, and the two second articulated supports are symmetrically arranged at the upper ends of the bottom plate. The driver comprises a first drive branch, a second drive branch, a third drive branch, and a fourth drive branch, each having the same structure and mounted on a corresponding first articulated support. The constraint branch comprises a first constraint branch and a second constraint branch, each having the same structure and mounted on a corresponding second articulated support. The present invention has the characteristics of being able to operate stably and continuously, effectively improving the speed and accuracy of skin polishing, and can greatly reduce the maintenance cost of the aircraft, thus having great economic value.

Description

Technical Field

[0001] The present invention relates to the technical field of parallel mechanisms, in particular to a four-degree-of-freedom parallel mechanism with two independently constrained branches. Background Art

[0002] The skin is a structural part of an aircraft body. It is in direct contact with the outside air and is therefore easily damaged by air corrosion and friction. In order to ensure the smoothness of the skin surface and its good aerodynamic performance, we need to perform maintenance work on the aircraft skin in a timely manner, including polishing.

[0003] The skin polishing work is currently mainly done manually, which has problems such as low polishing efficiency, poor precision, high cost, and even incorrect polishing. Therefore, we urgently need to develop automated polishing equipment based on parallel mechanisms to replace manual polishing. Summary of the Invention

[0004] The object of the present invention is to provide a four-degree-of-freedom parallel mechanism with two independently constrained branches to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a four-degree-of-freedom parallel mechanism with two independent constraint branches, comprising a base, a driver, a constraint branch and a moving platform, the base comprising a bottom plate, four first articulated supports and two second articulated supports, the four first articulated supports being evenly arranged at the four corners of the upper part of the bottom plate, the two second articulated supports being symmetrically arranged at the two ends of the upper part of the bottom plate, the driver comprising a first drive branch, a second drive branch, a third drive branch and a fourth drive branch having the same structure and each being mounted on a corresponding first articulated support, the constraint branch comprising a first constraint branch and a second constraint branch having the same structure and each being mounted on a corresponding second articulated support.

[0006] Preferably, the first drive branch chain, the second drive branch chain, the third drive branch chain and the fourth drive branch chain all include a motor, a telescopic cylinder, a base, a Hooke's joint and a ball joint. The lower end of the base is hinged to the first articulated support through a Hooke's joint. A first rotating pair and a second rotating pair are arranged between the base, the Hooke's joint and the first articulated support. The telescopic cylinder and the motor are both arranged on the upper part of the base, and the output end of the motor is connected to the inner end of the push rod on the telescopic cylinder; the end of the telescopic cylinder is hinged to the moving platform through a ball joint.

[0007] Preferably, the first constraint branch chain and the second constraint branch chain each include a first connecting rod, a second connecting rod and a second ball joint. The lower end of the first connecting rod and the second hinged support form a third rotation pair. The upper end of the first connecting rod and the lower end of the second connecting rod form a fourth rotation pair. The upper end of the second connecting rod is hinged to the moving platform through the second ball joint.

[0008] Preferably, the bottom plate is configured as a square plate.

[0009] Preferably, the moving platform is a square plate-shaped structure.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1. The present invention is provided with a first drive branch chain, a second drive branch chain, a third drive branch chain, and a fourth drive branch chain, which are identical in structure and highly symmetrical, and are symmetrically distributed at the four corners of the base plate. The first restraining branch chain and the second restraining branch chain are also identical in structure and spatially symmetrical, which facilitates production, processing, and installation, and greatly reduces production and maintenance costs.

[0012] 2. The present invention has four degrees of freedom and can adapt to various working conditions when polishing aircraft skin.

[0013] 3. The driving branch chain and the restraining branch chain in the present invention are separated, thus avoiding the use of a driving branch chain with restraints, and can greatly increase the strength and stability of the mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of a four-degree-of-freedom parallel mechanism with two independently constrained branches provided by the present invention.

[0015] Figure 2 This is a structural schematic diagram of the four-degree-of-freedom parallel mechanism with two independent constraint branches provided by the present invention, minus the moving platform.

[0016] Figure 3 This is a schematic structural diagram of a driving branch in a four-degree-of-freedom parallel mechanism with two independently constrained branches provided by the present invention.

[0017] Figure 4 This is a schematic structural diagram of a constraint branch in a four-degree-of-freedom parallel mechanism with two independent constraint branches provided by the present invention.

[0018] In the figure: 1, base; 101, first articulated support; 102, second articulated support; 103, bottom plate; 2, drive; 3, constraint branch chain; 4, moving platform; 5, motor; 6, telescopic cylinder; 7, base; 8, Hook's hinge; 9, first ball joint; 10, first constraint branch chain; 11, second constraint branch chain; 12, first connecting rod; 13, second connecting rod; 14, second ball joint; 15, first revolving pair; 16, second revolving pair; 17, third revolving pair; 18, fourth revolving pair; I, first drive branch chain; II, second drive branch chain; III, third drive branch chain; IV, fourth drive branch chain; DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] See also Figure 1-4 The present invention provides a technical solution: a four-degree-of-freedom parallel mechanism with two independent constraint branches, including a base 1, a driver 2, a constraint branch 3 and a moving platform 4, the base 1 includes a bottom plate 103, four first articulated supports 101 and two second articulated supports 102; the bottom plate 103 is a square plate; the four first articulated supports 101 are installed at the four corners of the top surface of the bottom plate 103 in a centrally symmetrical manner; the two second articulated supports 102 are installed at the center of the two parallel sides of the top surface of the bottom plate 103 in a centrally symmetrical manner, the driver 2 includes a first drive branch I, a second drive branch II, a third drive branch III and a fourth drive branch IV with the same structure and installed on the first articulated support 101; the first drive branch I, the second drive branch II, the third drive branch III and the fourth drive branch IV of the first articulated support 101 all include a motor 5, a telescopic cylinder 6, a base 7, a Hooke's joint 8 and a ball joint 9; the lower end of the base 7 is hinged by a Hooke's joint 8 The first hinge support 101 is connected to form a first rotation pair 15 and a second rotation pair 16. The rotation axis of the first rotation pair 15 is parallel to the long side of the bottom surface of the first hinge support 101, and the rotation axis of the second rotation pair 16 is perpendicular to the rotation axis of the first rotation pair 15. A motor 5 and a telescopic cylinder 6 are installed on each base 7. The output end of the motor 5 is connected to the inner end of the push rod on the telescopic cylinder 6. The end of the telescopic cylinder 6 is hinged to the moving platform 4 through a ball joint 9. The constraint support Chain 3 includes a first constraint branch 10 and a second constraint branch 11 of identical structure, mounted on a second hinged support 102. Each of the first and second constraint branches 10 and 11 includes a first connecting rod 12, a second connecting rod 13, and a second ball joint 14. The lower end of the first connecting rod 12 and the second hinged support 102 form a third rotational pair 17, while the upper end of the first connecting rod 12 and the lower end of the second connecting rod 13 form a fourth rotational pair 18. The upper end of the second connecting rod 13 is hinged to the movable platform 4 via the second ball joint 14. The rotation axis of the third rotational pair 17 is parallel to the rotation axis of the fourth rotational pair 18. The movable platform 4 is a square, plate-like structure.

[0021] Now, the vertical direction of the top surface of the base plate 1 is taken as the z-axis direction, the direction of the edge of the base plate 1 with the constraint branch is taken as the y-axis direction, and the x-axis direction is determined by the right-hand rule. The working principle of the four-degree-of-freedom parallel mechanism with two independent constraint branches provided by the present invention is explained as follows:

[0022] When using this four-degree-of-freedom parallel mechanism with two independently constrained branches for polishing aircraft skins, the four motors 5 are first driven, with the four telescopic cylinders 6 acting as active pairs. Because the constrained branches 3, articulated to the second articulated support 102, are mounted centrally and symmetrically at the center of two parallel edges on the top surface of the base plate 103, the mechanism's translational motion along the y-axis is restricted. Simultaneously, the third and fourth rotational pairs 17 and 18 effectively restrict the mechanism's rotational motion along the z-axis. Consequently, the mechanism can translate in the x and z directions, and rotate in the x and y directions, for a total of four degrees of freedom.

[0023] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0024] While 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 these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A four-degree-of-freedom parallel mechanism with two independently constrained branches, characterized by: The invention comprises a base (1), a driver (2), a constraint branch chain (3) and a moving platform (4); the base (1) comprises a bottom plate (103), four first articulated supports (101) and two second articulated supports (102); the four first articulated supports (101) are evenly arranged at the four corners of the upper part of the bottom plate (103); the two second articulated supports (102) are symmetrically arranged at the two ends of the upper part of the bottom plate (103); the driver (2) comprises a first drive branch chain (I), a second drive branch chain (II), a third drive branch chain (III) and a fourth drive branch chain (IV) which have the same structure and are respectively installed on the corresponding first articulated supports (101); the constraint branch chain (3) comprises a first constraint branch chain (10) and a second constraint branch chain (11) which have the same structure and are respectively installed on the corresponding second articulated supports (102).

2. A four-degree-of-freedom parallel mechanism with two independently constrained branches according to claim 1, characterized in that: The first drive branch chain (I), the second drive branch chain (II), the third drive branch chain (III) and the fourth drive branch chain (IV) all include a motor (5), a telescopic cylinder (6), a base (7), a Hooke's hinge (8) and a ball joint (9); the lower end of the base (7) is hinged to the first hinge support (101) through the Hooke's hinge (8); a first rotating pair (15) and a second rotating pair (16) are provided between the base (7), the Hooke's hinge (8) and the first hinge support (101); the telescopic cylinder (6) and the motor (5) are both provided on the upper part of the base (7); the output end of the motor (5) is connected to the inner end of the push rod on the telescopic cylinder (6); and the end of the telescopic cylinder (6) is hinged to the moving platform (4) through the ball joint (9).

3. The four-degree-of-freedom parallel mechanism with two independently constrained branches according to claim 1, characterized in that: The first constraint branch chain (10) and the second constraint branch chain (11) both include a first connecting rod (12), a second connecting rod (13) and a second ball joint (14); the lower end of the first connecting rod (12) and the second hinged support (102) form a third rotating pair (17); the upper end of the first connecting rod (12) and the lower end of the second connecting rod (13) form a fourth rotating pair (18); the upper end of the second connecting rod (13) is hinged to the moving platform (4) through the second ball joint (14).

4. The four-degree-of-freedom parallel mechanism with two independently constrained branches according to claim 1, characterized in that: The bottom plate (103) is configured as a square plate.

5. The four-degree-of-freedom parallel mechanism with two independently constrained branches according to claim 1, characterized in that: The moving platform (4) is a square plate-shaped structure.

Images