Six-degree-of-freedom parallel mechanism with decoupled primary and secondary drive motions

Abstract

The present invention relates to the field of mechanism technology, and in particular to a six-degree-of-freedom parallel mechanism with decoupling of primary and secondary drive motions, comprising a static platform, a dynamic platform, a hybrid branch chain, a first simple branch chain and a second simple branch chain. Slider one of guide rail one is connected to the dynamic platform via the hybrid branch chain, slider two on guide rail two is connected to the dynamic platform via the first simple branch chain, and slider three on guide rail three is connected to the dynamic platform via the second simple branch chain. When slider one, slider two, slider three, rotating pair one, rotating pair two and rotating pair seven are driven, the dynamic platform can generate three-translational and three-rotational output motions of six degrees of freedom. The present invention is not only suitable for operating long-scale workpieces or parts of long-scale workpieces that are separated by a long distance, and has high work efficiency, but also can realize precise motion in a small range, and can have good strength, stiffness and other properties and can withstand large loads; at the same time, it also has good motion decoupling, which is beneficial to motion control and trajectory planning.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanism, in particular to a six-degree-of-freedom parallel mechanism with decoupling of primary and secondary drive motions. Background Art

[0002] The n driving pairs of a traditional parallel mechanism with n degrees of freedom basically participate in the energy input (method, quantity, order, etc.) to the mechanism on an equal footing throughout the entire period of motion, including: the range of motion, sequence, (angular) velocity, etc., which can be referred to as an "equally driven parallel mechanism". Many scholars at home and abroad have conducted a lot of research on this and invented many such parallel mechanisms.

[0003] However, this type of parallel mechanism causes waste of energy and time and low efficiency in certain application scenarios, such as operating long workpieces or operating long workpieces at long distances (machining, welding, spraying, deburring, etc.), and new technologies are urgently needed to improve it. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: in order to solve the deficiencies in the prior art, a six-degree-of-freedom parallel mechanism with decoupling of primary and secondary drive motions is provided. The mechanism has the advantages of simple structure, zero coupling degree, analytical kinematic positive solution, partial motion decoupling, etc., and can be used for operations (machining, welding, spraying, deburring, etc.) on long-scale workpieces or parts of long-scale workpieces separated by a long distance.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a six-degree-of-freedom parallel mechanism with decoupled primary and secondary drive motions, comprising a static platform, a dynamic platform, a hybrid branch chain, a first simple branch chain, and a second simple branch chain; the static platform is provided with a first guide rail, a second guide rail, and a third guide rail; the axis of the second guide rail and the axis of the third guide rail are parallel to each other or coincident and collinear, and the axis of the second guide rail and the axis of the third guide rail are both parallel to the axis of the first guide rail;

[0006] The moving platform has a first connecting end, a second connecting end and a third connecting end;

[0007] The guide rail 1 is provided with a slider 1 that can move linearly back and forth along its axis. The hybrid branch chain includes a ball pair 1 and a two-degree-of-freedom planar five-bar mechanism. The planar five-bar mechanism is composed of a revolving pair 2, a revolving pair 3, a revolving pair 5, a revolving pair 4, and a revolving pair 1, whose axes are parallel to each other and are connected in series. The revolving pair 2 and the revolving pair 1 are both provided on the slider 1. The connecting rod between the revolving pair 3 and the revolving pair 5 is an output connecting rod, and the output connecting rod is connected to the first connecting end of the moving platform via the ball pair 1. The moving direction of the slider 1 is perpendicular to the motion plane of the planar five-bar mechanism.

[0008] The guide rail 2 is provided with a slider 2 that can reciprocate linearly along its axis. The first simple branch chain is composed of a ball pair 2, a revolving pair 6, and a revolving pair 7 connected in series. The ball pair 2 is connected to the second connection end of the moving platform. The revolving pair 7 is provided on the slider 2. The axis of the revolving pair 6, the axis of the revolving pair 7, and the moving direction of the slider 2 are parallel to each other.

[0009] The guide rail three is provided with a slider three for linear reciprocating movement along its axis. The second simple branch chain is composed of a ball pair three, a rotating pair nine, and a rotating pair eight connected in series. The ball pair three is connected to the third connecting end of the moving platform. The rotating pair eight is provided on the slider three. The axis of the rotating pair nine is parallel to the axis of the rotating pair eight.

[0010] When slider 1, slider 2, slider 3, revolute pair 1, revolute pair 2 and revolute pair 3 are driven, the dynamic platform can generate three translation and three rotation output motions with six degrees of freedom.

[0011] Furthermore, the axis of the rotating pair one, the axis of the rotating pair two, the axis of the rotating pair three, the axis of the rotating pair four, the axis of the rotating pair five, the axis of the rotating pair six, the axis of the rotating pair seven, the axis of the rotating pair eight, the axis of the rotating pair nine, the moving direction of the slider one, the moving direction of the slider two and the moving direction of the slider three are parallel to each other.

[0012] Furthermore, the slider 1 moving on the guide rail 1, the slider 2 moving on the guide rail 2 and the slider 3 moving on the guide rail 3 are all main driving pairs, and the rotation pair 1, the rotation pair 2 and the rotation pair 7 are all secondary driving pairs.

[0013] Furthermore, the first connection end, the second connection end and the third connection end are distributed in a triangle.

[0014] Furthermore, the six-degree-of-freedom parallel mechanism has a zero coupling degree, and has motion decoupling and an analytical position positive solution.

[0015] The beneficial effects of the present invention are as follows: the six-degree-of-freedom parallel mechanism with decoupling of primary and secondary drive motions of the present invention is not only suitable for operating long-scale workpieces or parts of long-scale workpieces separated by a long distance, with high work efficiency, but also can achieve precise motion in a small range, and has good strength, stiffness and other properties and can withstand large loads; at the same time, it also has good motion decoupling, which is beneficial to motion control and trajectory planning. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below with reference to the accompanying drawings and examples.

[0017] Figure 1 Schematic diagram of a six-degree-of-freedom parallel mechanism with decoupling of primary and secondary drive motions when the axis of the second guide rail is parallel to the axis of the third guide rail;

[0018] Figure 2 It is a schematic diagram of a six-degree-of-freedom parallel mechanism of the present invention with decoupling of primary and secondary drive motions when the axis of the guide rail two and the axis of the guide rail three are parallel.

[0019] In the figure: 0, static platform, 1, dynamic platform, 2, output connecting rod;

[0020] 10. Slider 1, 11. Slider 2, 12. Slider 3;

[0021] A, guide rail 1, B, guide rail 2, C, guide rail 3;

[0022] S1, ball pair one, S2, ball pair two, S3, ball pair three;

[0023] R1, rotation pair one, R2, rotation pair two, R3, rotation pair three, R4, rotation pair four, R5, rotation pair five, R6, rotation pair six, R7, rotation pair seven, R8, rotation pair eight, R9, rotation pair nine. DETAILED DESCRIPTION

[0024] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams that illustrate the basic structure of the present invention only in a schematic manner. Therefore, they only show components relevant to the present invention, and directions and references (e.g., up, down, left, right, etc.) may be used solely to facilitate the description of features in the drawings. The following detailed description is therefore not to be taken in a limiting sense, and the scope of the claimed subject matter is defined solely by the appended claims and their equivalents.

[0025] By observing the growth structures of numerous trees in the natural plant kingdom, the inventors discovered that all trees are composed of a main trunk and branches: a single trunk (called "primary") followed by two or more branches (called "secondary"), with the vast majority consisting of two branches. Each branch then follows the same pattern, with two or more sub-branches. These trees are able to withstand the rigors of nature and possess the highest vitality (strength, rigidity, durability, and flexibility). Therefore, this "primary-secondary" structure is the optimal outcome of natural evolution and selection based on the principle of "survival of the fittest."

[0026] This inspired us to develop a branch chain with two driving sources (primary-secondary driving branch chain, represented by: PR +..., underline indicates drive), which has important reference value for designing parallel mechanisms with good "strength, stiffness and other properties" and capable of bearing large loads. The applicant believes that: this primary-secondary drive branch chain ( PRThe design idea of the sled should be: use the larger slider as the main drive (moving P pair), and then fix one or more rotary motors on the slider as the secondary drive (rotating R pair); and then connect other moving pairs in series behind the R pair.

[0027] To this end, the present invention proposes a "primary and secondary drive parallel mechanism", that is, at different stages of the entire motion process, different drive pairs have different ways, quantities, and sequences of energy input to the mechanism, including: the range of motion, sequence, (angular) velocity, etc. Among them, the one with a longer input motion range and a larger input (angular) velocity is called a "primary drive pair", and the rest are called "secondary drive pairs".

[0028] The topological characteristics of this type of parallel mechanism are: it has one or more "primary drive pairs," each consisting of one or more main sliders (or main rotating arms) that move along long guide rails. Several "secondary drive pairs," including rotating and moving pairs, are then mounted on the main sliders (or main rotating arms). When there is only one "primary drive pair," it can be considered a mixed series-parallel parallel mechanism.

[0029] This type of parallel mechanism is not only suitable for operating long-scale workpieces or parts of long-scale workpieces separated by a long distance, with high work efficiency, but also has good motion decoupling, which is beneficial to motion control and trajectory planning.

[0030] Therefore, the problems of energy and time waste and low efficiency existing in the "equal drive type parallel mechanism" are overcome by the six-degree-of-freedom parallel mechanism with decoupling of primary and secondary drive motions in this embodiment.

[0031] like Figure 1-2 As shown, a six-degree-of-freedom parallel mechanism with decoupling of primary and secondary drive motions comprises a static platform 0, a dynamic platform 1, a hybrid branch chain, a first simple branch chain, and a second simple branch chain;

[0032] The static platform 0 is provided with a guide rail A, a guide rail B and a guide rail C; Figure 1 As shown, the axis of the guide rail 2 B and the axis of the guide rail 3 C are parallel to each other, and the axis of the guide rail 2 B and the axis of the guide rail 3 C are parallel to the axis of the guide rail 1 A. At this time, the guide rails 1 A, 2 B and 3 C do not contact each other; or, as shown Figure 2 As shown, the axis of guide rail 2 B and the axis of guide rail 3 C coincide and are collinear, and the axis of guide rail 2 B and the axis of guide rail 3 C are both parallel to the axis of guide rail 1 A. At this time, guide rail 2 B and guide rail 3 C can be regarded as integrally formed, but neither of them contacts guide rail 1 A.

[0033] The movable platform 1 has a first connecting end, a second connecting end and a third connecting end, and the first connecting end, the second connecting end and the third connecting end are distributed in a triangle, that is, the first connecting end, the second connecting end and the third connecting end are respectively distributed at the three vertices of the triangle;

[0034] Guide rail 1A is provided with a slider 10 for linear reciprocating movement along its axis. The hybrid branch chain includes a ball joint 1 S1 and a two-degree-of-freedom planar five-bar mechanism. The planar five-bar mechanism is composed of a second revolving joint R2, a third revolving joint R3, a fifth revolving joint R5, a fourth revolving joint R4, and a first revolving joint R1, whose axes are parallel to each other and connected in series. Both revolving joints R2 and R1 are provided on slider 10. The connecting rod between revolving joints R3 and R5 is the output connecting rod 2. The extended end of the output connecting rod 2 is connected to the first connecting end of the moving platform 1 via a ball joint 1 S1. The movement direction of slider 10 is perpendicular to the motion plane of the planar five-bar mechanism.

[0035] Guide rail 2 B is provided with a slider 2 11 for linear reciprocating movement along its axis. The first simple branch chain is composed of a ball joint 2 S2, a revolving joint 6 R6, and a revolving joint 7 R7 connected in series. Ball joint 2 S2 is connected to the second connection end of the moving platform 1. Revolving joint 7 R7 is provided on slider 2 11. The axis of revolving joint 6 R6, the axis of revolving joint 7 R7, and the direction of movement of slider 2 11 are parallel to each other.

[0036] Guide rail 3 C is provided with a slider 3 12 for linear reciprocating movement along its axis. The second simple branch chain is composed of a ball joint 3 S3, a revolving joint 9 R9, and a revolving joint 8 R8 connected in series. Ball joint 3 S3 is connected to the third connection end of the moving platform 1. Revolving joint 8 R8 is provided on slider 3 12. The axis of revolving joint 9 R9 is parallel to the axis of revolving joint 8 R8.

[0037] When slider 10, slider 2 11, slider 3 12, rotation pair 1 R1, rotation pair 2 R2 and rotation pair 7 R7 are driven, the dynamic platform 1 can generate three translation and three rotation output motions with six degrees of freedom; specifically, slider 10 moving on guide rail 1 A, slider 2 11 moving on guide rail 2 B and slider 3 12 moving on guide rail 3 C can all be main drive pairs, and rotation pair 1 R1, rotation pair 2 R2 and rotation pair 7 R7 can all be secondary drive pairs; the coupling degree of this six-degree-of-freedom parallel mechanism is zero, and it has motion decoupling and analytical position positive solution.

[0038] The parallel mechanism in this embodiment can achieve a large range of long-distance movement / working space when slider one 10, slider two 11 and slider three 12 move at the same speed and in the same direction; and when the speeds and directions of the three are different, a small range of precise movement can be achieved.

[0039] In some embodiments, the axis of the rotating pair R1, the axis of the rotating pair R2, the axis of the rotating pair R3, the axis of the rotating pair R4, the axis of the rotating pair R5, the axis of the rotating pair R6, the axis of the rotating pair R7, the axis of the rotating pair R8, the axis of the rotating pair R9, the moving direction of the slider 10, the moving direction of the slider 2 11 and the moving direction of the slider 3 12 are parallel to each other, which can facilitate assembly and manufacturing and facilitate dynamic analysis.

[0040] The six-degree-of-freedom parallel mechanism with decoupled primary and secondary drive motions in this embodiment has the following three advantages: 1) The structure is simpler, consisting only of a low pair, easy to manufacture and simple to install; 2) The motion has partial motion decoupling, and it is easy to obtain a symbolic position solution, which makes the kinematics, motion control, trajectory planning, and dynamic analysis of the six-degree-of-freedom parallel mechanism easy and convenient; 3) The working space is large. When slider one 10, slider two 11, and slider three 12 move at the same speed and in the same direction, the six-degree-of-freedom parallel mechanism can operate over a long distance.

[0041] The six-degree-of-freedom parallel mechanism with decoupled primary and secondary drive motions can be used for manufacturing operations (grinding, riveting, spraying, etc.) on long or extra-long workpieces (for example, the fuselage and wings of large aircraft, blades of large wind turbines, etc.).

[0042] The above description of the preferred embodiments of the present invention is intended to serve as a guide. Based on the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A six-degree-of-freedom parallel mechanism with decoupled primary and secondary drive motions, comprising a static platform (0), a dynamic platform (1), a hybrid branch chain, a first simple branch chain, and a second simple branch chain, characterized in that: The static platform (0) is provided with a guide rail 1 (A), a guide rail 2 (B) and a guide rail 3 (C), the axis of the guide rail 2 (B) and the axis of the guide rail 3 (C) are parallel to each other or coincident and collinear, and the axis of the guide rail 2 (B) and the axis of the guide rail 3 (C) are both parallel to the axis of the guide rail 1 (A); The movable platform (1) has a first connecting end, a second connecting end and a third connecting end; The guide rail 1 (A) is provided with a slider 1 (10) which can move linearly back and forth along its axis direction. The hybrid branch chain includes a ball pair 1 (S1) and a two-degree-of-freedom planar five-bar mechanism. The planar five-bar mechanism is composed of a rotation pair 2 (R2), a rotation pair 3 (R3), a rotation pair 5 (R5), a rotation pair 4 (R4) and a rotation pair 1 (R1) whose axes are parallel to each other and connected in series in sequence. The rotation pair 2 (R2) and the rotation pair 1 (R1) are both provided on the slider 1 (10). The connecting rod between the rotation pair 3 (R3) and the rotation pair 5 (R5) is an output connecting rod (2). The output connecting rod (2) is connected to the first connecting end of the moving platform (1) through the ball pair 1 (S1); the moving direction of the slider 1 (10) is perpendicular to the motion plane of the planar five-bar mechanism; The guide rail 2 (B) is provided with a slider 2 (11) which can move linearly back and forth along its axis. The first simple branch chain is composed of a ball pair 2 (S2), a rotating pair 6 (R6) and a rotating pair 7 (R7) connected in series. The ball pair 2 (S2) is connected to the second connection end of the moving platform (1). The rotating pair 7 (R7) is provided on the slider 2 (11). The axis of the rotating pair 6 (R6), the axis of the rotating pair 7 (R7) and the moving direction of the slider 2 (11) are parallel to each other. The guide rail three (C) is provided with a slider three (12) which can move linearly back and forth along its axis direction. The second simple branch chain is composed of a ball pair three (S3), a rotating pair nine (R9) and a rotating pair eight (R8) connected in series in sequence. The ball pair three (S3) is connected to the third connection end of the moving platform (1). The rotating pair eight (R8) is provided on the slider three (12). The axis of the rotating pair nine (R9) is parallel to the axis of the rotating pair eight (R8). When the slider 1 (10), the slider 2 (11), the slider 3 (12), the rotation pair 1 (R1), the rotation pair 2 (R2) and the rotation pair 7 (R7) are driven, the moving platform (1) can generate three translation and three rotation output motions with six degrees of freedom.

2. The six-degree-of-freedom parallel mechanism with decoupling of primary and secondary drive motions according to claim 1, characterized in that: The axis of the rotating pair 1 (R1), the axis of the rotating pair 2 (R2), the axis of the rotating pair 3 (R3), the axis of the rotating pair 4 (R4), the axis of the rotating pair 5 (R5), the axis of the rotating pair 6 (R6), the axis of the rotating pair 7 (R7), the axis of the rotating pair 8 (R8), the axis of the rotating pair 9 (R9), the moving direction of the slider 1 (10), the moving direction of the slider 2 (11) and the moving direction of the slider 3 (12) are parallel to each other.

3. The six-degree-of-freedom parallel mechanism with decoupling of primary and secondary drive motions according to claim 1, characterized in that: The slider 1 (10) moving on the guide rail 1 (A), the slider 2 (11) moving on the guide rail 2 (B) and the slider 3 (12) moving on the guide rail 3 (C) are all main driving pairs, and the rotation pair 1 (R1), the rotation pair 2 (R2) and the rotation pair 7 (R7) are all secondary driving pairs.

4. The six-degree-of-freedom parallel mechanism with decoupling of primary and secondary drive motions according to claim 1, characterized in that: The first connection end, the second connection end and the third connection end are distributed in a triangle shape.

5. The six-degree-of-freedom parallel mechanism with decoupling of primary and secondary drive motions according to claim 1, characterized in that: The six-degree-of-freedom parallel mechanism has zero coupling degree, motion decoupling and analytical position positive solution.

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