CN112192546A - Parallel mechanism driven by inner pair and outer pair in combined mode - Google Patents
Parallel mechanism driven by inner pair and outer pair in combined mode Download PDFInfo
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- CN112192546A CN112192546A CN202010954692.9A CN202010954692A CN112192546A CN 112192546 A CN112192546 A CN 112192546A CN 202010954692 A CN202010954692 A CN 202010954692A CN 112192546 A CN112192546 A CN 112192546A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/003—Programme-controlled manipulators having parallel kinematics
Abstract
The invention discloses a parallel mechanism driven by an inner pair and an outer pair in a combined way, which comprises: the device comprises a base, a movable platform, a first branched chain, a second branched chain and a third branched chain; the first branched chain and the second branched chain have the same structure and respectively comprise a universal pair connected with the base, a first revolute pair connected with the movable platform and a first moving pair connected with the universal pair and the first revolute pair; the third branched chain comprises a second moving pair connected with the base, a ball pair connected with the movable platform, and a second rotating pair connected with the ball pair and the second moving pair; the first moving pair and the second moving pair are driving pairs. According to the parallel mechanism, the first moving pair serving as the middle rod piece and the second moving pair directly connected with the base are both set as driving pairs, so that the integral rigidity of the parallel mechanism is effectively improved.
Description
Technical Field
The invention relates to the field of parallel structures, in particular to a parallel mechanism driven by an inner pair and an outer pair in a combined mode.
Background
At present, in a three-degree-of-freedom one-level two-rotation parallel mechanism adopted by a parallel-serial machine tool and a parallel-serial robot, a mobile driving pair is mainly positioned in a middle rod piece, namely, an internal driving mode is adopted. The structural design and the driving mode enable the parallel mechanism to have a large working space and to be easy to control, but reduce the rigidity of the mechanism to a certain extent.
Thus, there is still a need for improvement and development of the prior art.
SUMMARY OF THE PATENT FOR INVENTION
The present invention provides a parallel mechanism driven by an inner pair and an outer pair in a combined manner, aiming at solving the problem that the rigidity of the mechanism is reduced because the three-degree-of-freedom one-level two-rotation parallel mechanism with a fixed rotation direction mainly adopts an inner driving manner in the prior art.
The technical scheme adopted by the invention for solving the problems is as follows:
in a first aspect, an embodiment of the present invention provides an internal and external pair jointly driven parallel mechanism, where the internal and external pair jointly driven parallel mechanism includes: the base, the movable platform opposite to the base, and a first branched chain, a second branched chain and a third branched chain which are used for connecting the base and the movable platform; the third branched chain is arranged between the first branched chain and the second branched chain;
the first branched chain and the second branched chain have the same structure and respectively comprise a universal pair, a first moving pair and a first rotating pair; the universal pair is connected with the base; the first rotating pair is connected with the movable platform; the first sliding pair is connected with the universal pair and the first rotating pair;
the third branched chain comprises a second sliding pair, a second rotating pair and a ball pair; the second sliding pair is connected with the base; the ball pair is connected with the movable platform; the second revolute pair is connected with the ball pair and the second sliding pair;
the first moving pair and the second moving pair are driving pairs.
In one embodiment, the rotation directions of the universal pairs include a first rotation direction and a second rotation direction perpendicular to the first rotation direction;
the rotating direction of the first rotating pair is parallel to the second rotating direction;
the rotation direction of the second revolute pair is parallel to the first rotation direction.
In one embodiment, the gimbal pair comprises a first U-shaped member, a second U-shaped member movably connected with the first U-shaped member;
the first U-shaped part is fixedly connected with the base, a first through hole, a second through hole and a first rotating rod movably connected with the first through hole and the second through hole are formed in the upper end of the first U-shaped part, and the first through hole and the second through hole are oppositely arranged;
the second U-shaped piece is fixedly connected with the first moving pair; a third through hole, a fourth through hole and a second rotating rod movably connected with the third through hole and the fourth through hole are formed in the upper end of the second U-shaped part, and the third through hole and the fourth through hole are arranged oppositely; the first rotating rod is perpendicular to and fixedly connected with the second rotating rod;
when the first rotating rod rotates relative to the first through hole and the second through hole, the universal pair rotates in the first rotating direction;
when the second rotating rod rotates relative to the third through hole and the fourth through hole, the universal pair rotates in the second rotating direction.
In one embodiment, the first sliding pair comprises a first sliding chute and a first sliding rod connected with the first sliding chute in a sliding manner;
the first sliding groove is fixedly connected with the universal pair, and the first sliding rod is fixedly connected with the first rotating pair; the shape of the opening end of the first sliding groove is matched with the shape of the first sliding rod, and the first sliding groove is sleeved on the first sliding rod.
In one embodiment, the first rotary pair comprises a third U-shaped member, a third rotary shaft rotatably connected to the third U-shaped member;
the third U-shaped part is connected with the movable platform, a fifth through hole and a sixth through hole are formed in the upper end of the third U-shaped part, and the fifth through hole and the sixth through hole are arranged oppositely; the third rotating rod is movably connected with the fifth through hole and the sixth through hole; the third rotating rod is perpendicular to and fixedly connected with the first sliding pair; the rotating direction of the third rotating rod is the rotating direction of the first rotating pair.
In one embodiment, the second sliding pair comprises a second sliding chute and a second sliding rod which is connected with the second sliding chute in a sliding way;
the second sliding groove is fixedly connected with the base, and the second sliding rod is fixedly connected with the second revolute pair; the shape of the opening end of the second sliding chute is matched with the shape of the second sliding rod, and the second sliding chute is sleeved on the second sliding rod.
In one embodiment, the second rotation pair comprises a fourth U-shaped member and a fourth rotation rod rotatably connected to the fourth U-shaped member;
the fourth U-shaped piece is fixedly connected with the second moving pair; a seventh through hole and an eighth through hole are formed in the upper end of the fourth U-shaped part, and the seventh through hole and the eighth through hole are arranged oppositely; the fourth rotating rod is movably connected with the seventh through hole and the eighth through hole; the fourth rotating rod is fixedly connected with the ball pair; the rotation direction of the fourth rotating rod is the rotation direction of the second rotating pair.
In one embodiment, the ball pair comprises a fixed seat and a movable part movably connected with the fixed seat;
the movable piece comprises a spherical part and a connecting rod fixedly connected with the spherical part, and the other end of the connecting rod is fixedly connected with the second revolute pair;
the bottom of the fixed seat is fixedly connected with the movable platform, and the fixed seat is a hemispherical groove body; the hemispherical groove body is movably connected with the spherical part.
In one embodiment, the movable platform has an area smaller than that of the base.
In one embodiment, the third branched chain is disposed on a perpendicular bisector of a line segment with the bottoms of the first branched chain and the second branched chain as end points.
The invention has the beneficial effects that: according to the invention, the first moving pair as the middle rod piece and the second moving pair directly connected with the base are both set as driving pairs, so that the parallel mechanism comprises an inner driving pair and an outer driving pair at the same time. The working space of the parallel mechanism can be effectively enlarged by the internal driving mode, and the driving pair is directly connected with the base in the external driving mode, so that the capability of resisting elastic deformation of the parallel mechanism when stressed can be effectively improved. Therefore, the invention can effectively improve the integral rigidity of the parallel mechanism while keeping the working space of the parallel mechanism.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a parallel mechanism driven by an inner pair and an outer pair in a combined manner according to an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of the first branch/the second branch provided in the embodiment of the present invention.
Fig. 3 is a schematic structural diagram of a third branch chain provided in an embodiment of the present invention.
The reference numbers illustrate:
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1 | First moving |
15 |
| Movable platform | 2 | First rotating |
16 |
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5 | Fourth U-shaped |
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| First U-shaped |
6 | Fourth rotating |
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| First rotating |
7 | Connecting |
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| Second rotating |
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| Second U-shaped |
9 | Fixed |
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10 | Second moving |
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11 | Second revolute pair | 25 |
| Third rotating |
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Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It should be noted that, if directional indications (such as up, down, left, right, front, and back) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the motion situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.
In recent years, a large number of hybrid machine tools and hybrid robots are applied to high-end manufacturing industries such as aerospace industry, automobile industry and optical engineering to solve the operation tasks such as polishing, spraying, drilling, assembling and friction stir welding which have high requirements on equipment precision and rigidity. The main bodies of the series-parallel machine tool and the series-parallel robot are parallel mechanisms, and the parallel mechanisms can be defined as: the mechanism that the upper platform and the lower platform are connected by 2 or more than 2 branched chains and driven in a parallel way is called as a parallel mechanism. The three-degree-of-freedom one-level two-rotation parallel mechanism has the advantages of large occupied area ratio of a working space to a machine body, flexible attitude space, excellent dynamic characteristics and the like, and is widely adopted.
Currently, typical three-degree-of-freedom one-to-two rotation parallel mechanisms include a 3UPS-UP parallel mechanism developed by spanish PKM Tricept, a 2UPR-SPR parallel mechanism developed by Exechon, sweden, a 2UPR-RPS parallel mechanism developed by yanshan university, a 2UPR-RPU parallel mechanism developed by zhe jiang university, and a 2UPR-RRU parallel mechanism developed by ataxia university (letters R, P, U, S in the parallel mechanisms respectively refer to a revolute pair, a mobile pair, a universal pair, and a ball pair). However, in the above three-degree-of-freedom one-plane two-rotation parallel main structure, the movable driving pairs are all located in the middle of the middle rod, i.e. an internal driving manner is adopted. The structural design and the driving mode enable the parallel mechanism to have a large working space and to be easy to control, but reduce the rigidity of the mechanism to a certain extent.
In order to solve the above problems in the prior art, the present embodiment provides an internal and external pair jointly driven parallel mechanism, specifically as shown in fig. 1, the internal and external pair jointly driven parallel mechanism includes: the device comprises a base 1 and a movable platform 2 arranged opposite to the base 1. The base 1 plays a stable and firm role in the whole parallel structure. The moving platform 2 is a moving platform, and performs relative movement or pose transformation on the base 1. A first branched chain 3 and a second branched chain 4 are arranged between the base 1 and the movable platform 2. Namely, the movable platform 2 is equivalently supported by a plurality of branched chains at the same time, so that the whole parallel mechanism has the advantages of stable structure and strong bearing capacity.
In this embodiment, in order to realize the movement of the movable platform 2, the first branch chain 3 and the second branch chain 4 are provided in a form of connecting a plurality of kinematic pairs in series, so that the movable platform 2 realizes different pose transformations along with the movement of different kinematic pairs on the branch chains. In brief, a kinematic pair is a kinematic assembly composed of two or more members, and the members are in direct contact with each other and movably connected to each other. The two components of the kinematic pair can be divided into a moving pair, a rotating pair, a universal pair and a ball pair according to the relative motion property between the two components. The moving pair refers to a moving pair which can only move relatively between two components forming the moving pair; the revolute pair refers to a kinematic pair which can only do relative rotation between two components forming the kinematic pair; the universal pair refers to a kinematic pair which can make relative rotation in two directions between two components forming the kinematic pair. Because the motion forms of different kinematic pairs are different, after the kinematic pairs are combined, the different kinematic pairs can form constraint mutually during motion, and thereby the pose transformation of the movable platform 2 is formed together.
As shown in fig. 2, the first branch chain 3 and the second branch chain 4 have the same structure, and each of them includes a universal pair 14, a first moving pair 15 and a first rotating pair 16; the universal pair 14 is connected with the base 1; the first rotating pair 16 is connected with the movable platform 2; the first moving pair 15 is connected to both the universal pair 14 and the first rotating pair 16.
Specifically, the universal pair 14 is connected with the base 1, so that when the universal pair 14 rotates, the whole chain can be driven to rotate from the bottom of the branched chain, and the rotation of the movable platform 2 is realized. The first rotating pair 16 is connected with the moving platform 2, so that when the other moving pairs of the branched chain where the first rotating pair is located are kept still, the first rotating pair can independently rotate to drive the moving platform 2 to move. The universal pair 14 and the first rotating pair 16 are connected by the first moving pair 15, and the first moving pair 15 can drive the moving platform 2 to translate, so that the moving platform 2 moves closer to or away from the base 1.
In order to enhance the bearing capacity and the stability of the movable platform 2 during movement, as shown in fig. 1, a third branch chain 5 is further disposed between the first branch chain 3 and the second branch chain 4. As shown in fig. 3, the third branched chain 5 includes a second sliding pair 24, a second rotating pair 25 and a ball pair 27. The second sliding pair 24 is connected with the base 1, the ball pair 27 is connected with the movable platform 2, and the second revolute pair 25 is connected with the ball pair 27 and the second sliding pair 24. Specifically, the ball pair refers to a kinematic pair which can rotate relatively in any direction between two members constituting the kinematic pair, and since the ball pair can rotate in more directions compared with a kinematic pair, a revolute pair, and a universal pair, after the ball pair 27 is connected with the movable platform 2, it does not affect the motion of other kinematic pairs on the first branch chain 3 and the second branch chain 4, so that the limitation of the motion range of the movable platform 2 can be effectively avoided.
In addition, in order to increase the rigidity of the parallel mechanism of the inner and outer pair combined drive, the first and second sliding pairs 15 and 24 are provided as drive pairs in the present embodiment. Specifically, the driving pair refers to a kinematic pair in which the relative motion law of two members of the kinematic pair in the parallel mechanism is known, that is, the kinematic pair has a driving effect between the two members. And the kinematic pair which is not the driving pair in the parallel mechanism is the driven pair. When the driving pair is the middle rod piece, namely the driving pair is not directly connected with the base 1, the driving pair adopts an internal driving mode, so that the parallel mechanism has larger working space and is easy to control, but the rigidity of the parallel mechanism is reduced to a certain extent. When the driving pair is directly connected with the base 1, the driving pair is in an external driving mode, and the driving pair is directly connected with the base 1 in the external driving mode, so that the capacity of resisting elastic deformation when the parallel mechanism is stressed can be effectively improved, namely the rigidity of the parallel mechanism is improved. In this embodiment, the first sliding pair 15 serving as an intermediate rod and the second sliding pair 24 directly connected to the base 1 are both provided as driving pairs, and the driving motor is connected to the screw guide rail to realize the translational motion of the first sliding pair 15 and the second sliding pair 24, so that the parallel mechanism includes both an inner driving pair and an outer driving pair, and thus, the parallel mechanism has a large working space and simultaneously can effectively improve the overall rigidity of the parallel mechanism.
Because the three branched chains supporting the movable platform 2 all comprise a pair of movable chains capable of rotating, the rotating directions of the three branched chains need to be reasonably set so that the three branched chains can be mutually matched to further realize that the movable platform 2 rotates relative to the base 1. In one implementation, the rotational directions of the universal pairs 14 include a first rotational direction and a second rotational direction perpendicular to the first rotational direction, the rotational direction of the first rotational pair 16 is parallel to the second rotational direction, and the rotational direction of the second rotational pair 25 is parallel to the first rotational direction.
Specifically, the moving directions of all kinematic pairs in the parallel mechanism jointly construct the moving range and the pose transformation mode of the parallel mechanism. Therefore, in order to properly set the moving direction of each kinematic pair, in this embodiment, the rotating directions of the first rotating pair 16 and the second rotating pair 25 may be set based on the rotating direction of the universal pair 14. As shown in fig. 2, taking the coordinate system of fig. 2 as an example, the rotation directions of the universal pair 14 include a first rotation direction and a second rotation direction perpendicular to the first rotation direction, the first rotation direction is a direction of rotation around the Y axis, and the second rotation direction is a direction of rotation around the X axis. In order to cooperate with the rotation of the universal pair 14, the rotation direction of the first rotation pair 16 is set to be parallel to the second rotation direction, the rotation direction of the second rotation pair 25 is parallel to the first rotation direction, and in addition, the cooperation of the ball pair 27 finally enables the movable platform 2 to comprise two rotation directions, wherein one rotation direction is parallel to the first rotation direction, and the other rotation direction is parallel to the second rotation direction. Namely, the movable platform 2 can rotate in two directions, so that the parallel mechanism driven by the inner pair and the outer pair in a combined mode has two rotational degrees of freedom.
In addition, when the first sliding pair 15 and the second sliding pair 24 are driven linearly, the movable platform 2 can also perform translational motion. Therefore, the parallel mechanism driven by the inner pair and the outer pair in a combined mode further comprises a translation degree of freedom. It is understood that although the moving direction of the first moving pair 15 is parallel to the moving direction of the second moving pair 24, the moving direction of the first moving pair 15 and the moving direction of the second moving pair 24 may be the same direction or different directions, and the moving displacement of the first moving pair 15 and the moving displacement of the second moving pair 24 may also be equal or unequal. For example, when the first moving pair 15 and the second moving pair 24 both move 20 cm in the direction perpendicular to the plane of the base 1 and away from the plane of the base 1, it means that the moving platform 2 moves in a translational motion relative to the base 1, then the first moving pair 15 moves 10 cm in the direction perpendicular to the plane of the base 1 and close to the plane of the base 1, and the second moving pair 24 moves 5 cm in the direction perpendicular to the plane of the base 1 and away from the plane of the base 1, and the universal pair 14, the second rotating pair 25, the ball pair 27, and other driven pairs are engaged, so as to rotate the moving platform 2 in the direction parallel to the first rotation direction.
In one implementation, the first sliding pair 15 can be divided into a left sliding pair on the first branch chain 3 and a right sliding pair on the second branch chain 4. Similarly, the moving direction of the left moving pair and the moving direction of the right moving pair may be the same or different, and the moving displacement of the left moving pair and the moving displacement of the right moving pair may also be equal or unequal. For example, when the left moving pair, the right moving pair and the second moving pair 24 all move 20 cm in a direction perpendicular to the plane of the base 1 and away from the plane of the base 1, it means that the moving platform 2 moves in a translational motion relative to the base 1, then the left moving pair moves 10 cm in a direction perpendicular to the plane of the base 1 and close to the plane of the base 1, and the right moving pair moves 5 cm in a direction perpendicular to the plane of the base 1 and away from the plane of the base 1, and the second moving pair 24 is driven adaptively according to the motion of the left moving pair and the right moving pair, and in addition to the cooperation of the driven pairs such as the universal pair 14, the second rotating pair 25 and the ball pair 27, the moving platform 2 can rotate in a direction parallel to the second rotating direction.
In one implementation, as shown in fig. 2, the gimbal cross member 14 includes a first U-shaped member 6, and a second U-shaped member 9 movably connected to the first U-shaped member 6. The first U-shaped part 6 is fixedly connected with the base 1, a first through hole, a second through hole and a first rotating rod 7 movably connected with the first through hole and the second through hole are arranged at the upper end of the first U-shaped part 6, and the first through hole and the second through hole are oppositely arranged. Second U-shaped piece 9 with first removal vice 15 fixed connection, the upper end of second U-shaped piece 9 is provided with third through-hole, fourth through-hole, and with the third through-hole with fourth through-hole swing joint's second dwang 8, the third through-hole with the fourth through-hole sets up relatively. The first rotating rod 7 and the second rotating rod 8 are perpendicular and fixedly connected. When the first rotating rod 7 rotates relative to the first through hole and the second through hole, the universal pair rotates in the first rotating direction. And when the second rotating rod 8 rotates relatively to the third through hole and the fourth through hole, the universal pair rotates in the second rotating direction.
In particular, as shown in fig. 2, the bottom of the first U-shaped part 6 is fixedly connected to the base 1, i.e. the first U-shaped part 6 does not have a rotating function in the gimbal pair 14, but is fixedly connected to the base 1. The upper end of the first U-shaped part 6 is provided with a first through hole, a second through hole and a first rotating rod 7 movably connected with the first through hole and the second through hole, namely, the first rotating rod 7 can rotate in the first through hole and the second through hole. Because first dwang 7 with second dwang 8 is perpendicular and fixed connection relation, and second dwang 8 with second U-shaped spare 9 has connection relation again, consequently works as first dwang 7 is in first through-hole when rotating in the second through-hole, be equivalent to promptly second U-shaped spare with first dwang 7 rotates for the axis of rotation, thereby realizes universal vice 14 is in first direction of rotation rotates. The upper end of second U-shaped piece 9 is provided with third through-hole, fourth through-hole, and with the third through-hole fourth through-hole swing joint's second dwang 8, consequently second U-shaped piece 9 can also with second dwang 8 rotates for the axis of rotation, thereby realizes universal vice the second direction of rotation rotates.
In one implementation, as shown in fig. 2, the first sliding pair 15 includes a first sliding chute 10 and a first sliding rod 11 slidably connected to the first sliding chute 10. The first sliding chute 10 is fixedly connected with the universal pair 14, and the first sliding rod 11 is fixedly connected with the first rotating pair 16. The shape of the opening end of the first sliding chute 10 is matched with the shape of the first sliding rod 11, and the first sliding chute 10 is sleeved on the first sliding rod 11.
Specifically, the two members forming the sliding pair may have various specific forms, and in this embodiment, the first sliding chute 10 and the first sliding rod 11 form the first sliding pair 15, wherein the bottom of the first sliding chute 10 is fixedly connected to the universal pair 14, the open end of the first sliding chute 10 is connected to the first sliding rod 11, and the other end of the first sliding rod 11 is fixedly connected to the first rotating pair 16. The shape of the groove body of the first sliding groove 10 is matched with the shape of the first sliding rod 11, so that the motion track of the first sliding rod 11 is limited, the first sliding rod can only move linearly along the inner wall of the first sliding groove 10, and the accuracy of each action of the inner and outer pair combined driving parallel mechanism during motion is effectively improved. When a high sensitivity of the movement of the first sliding pair 15 is required, i.e. when it is desired to reduce the friction in the guide rail, in one implementation, a ball may be provided in the first runner 10, so as to convert the sliding friction between the first runner 10 and the first slide bar 11 into rolling friction, thereby greatly reducing the friction resistance between the first runner 10 and the first slide bar 11.
In one implementation, as shown in fig. 2, the first rotating pair 16 comprises a third U-shaped part 13, a third rotating rod 12 rotatably connected to the third U-shaped part 13, and the third U-shaped part 13 is connected to the movable platform 2. A fifth through hole and a sixth through hole are formed in the upper end of the third U-shaped part 13, and the fifth through hole and the sixth through hole are arranged oppositely. The third rotating rod 12 is movably connected with the fifth through hole and the sixth through hole, and the third rotating rod 12 is perpendicular to and fixedly connected with the first sliding pair 15. The rotation direction of the third rotating lever 12 is the rotation direction of the first rotating pair 16.
Specifically, when the third rotating rod 12 rotates relative to the fifth through hole and the sixth through hole, the third U-shaped member 13 rotates with the third rotating rod 12 as a rotating shaft. Since the rotation direction of the third rotating lever 12 is the rotation direction of the first rotating pair 16, and the rotation direction of the first rotating pair 16 is parallel to the second rotation direction, the third rotating lever 12 should be set to be parallel to the second rotating lever 8 in the initial configuration of the parallel mechanism of the combined driving of the inner and outer pairs. Because the bottom of the third U-shaped part 13 is fixedly connected to the movable platform 2, when the third U-shaped part 13 rotates with the third rotating rod 12 as a rotating shaft, the movable platform 2 also rotates.
In order to realize the stable connection between the third rotating rod 12 and the first sliding pair 15, in one implementation manner, one end of the first sliding rod 11 is provided with a circular ring structure, and the circular ring structure is used for stably sleeving the first sliding rod 11 on the middle portion of the third rotating rod 12. Specifically, the inner peripheral surface of the circular ring structure is fixedly connected with the third rotating rod 12, and the outer peripheral surface of the circular ring structure is fixedly connected with one end of the first sliding rod 11, so that the stable connection between the third rotating rod 12 and the first sliding rod 11 is realized.
In order to improve the structural strength of the first/ second branch chain 3, 4, in an implementation manner, the second U-shaped element 9 and the first sliding groove 10 may be configured as an integrated structure, and the first sliding rod 11 and the third rotating rod 12 may be configured as an integrated structure. Therefore, when the two components fixed with each other move integrally, the relative displacement is avoided due to insufficient stability of fixation, and the integral movement precision of the mechanism is reduced.
In one implementation, as shown in fig. 3, the second sliding pair 24 includes a second sliding chute 17, and a second sliding rod 18 slidably connected to the second sliding chute 17; the second sliding chute 17 is fixedly connected with the base 1, and the second sliding rod 18 is fixedly connected with the second revolute pair 25; the shape of the opening end of the second sliding chute 17 is matched with the shape of the second sliding rod 18, and the second sliding chute 17 is sleeved on the second sliding rod 18.
Specifically, the bottom of the second sliding chute 17 is fixedly connected to the base 1, the open end of the second sliding chute 17 is connected to the second sliding rod 18, and the other end of the second sliding rod 18 is fixedly connected to the second revolute pair 25. The shape of the groove body of the second sliding groove 17 is matched with the shape of the second sliding rod 18, so that the motion track of the second sliding rod 18 is limited, the second sliding rod can only move linearly along the inner wall of the second sliding groove 17, and the accuracy of each action during the motion of the parallel mechanism driven by the inner pair and the outer pair in a combined mode is effectively improved. It will be understood that, like the first sliding pair 15, the sliding friction between the second runner 17 and the second sliding bar 18 can also be converted into rolling friction when it is necessary to reduce the friction resistance of the first sliding pair 15.
In one implementation, as shown in fig. 3, the second rotation pair 25 comprises a fourth U-shaped member 19 and a fourth rotation rod 20 rotatably connected to the fourth U-shaped member 19. The fourth U-shaped element 19 is fixedly connected to the second sliding pair 24; a seventh through hole and an eighth through hole are formed in the upper end of the fourth U-shaped part 19, and the seventh through hole and the eighth through hole are arranged oppositely. The fourth rotating rod 20 is movably connected with the seventh through hole and the eighth through hole; the fourth rotating rod 20 is fixedly connected with the ball pair 27. The rotation direction of the fourth rotating rod 20 is the rotation direction of the second rotating pair 25.
Specifically, when the fourth rotating rod 20 rotates relative to the seventh through hole and the eighth through hole, it is equivalent to that the fourth U-shaped member 19 rotates with the fourth rotating rod 20 as a rotating shaft. Since the rotation direction of the fourth rotating rod 20 is the rotation direction of the second rotating pair 25, and the rotation direction of the second rotating pair 25 is parallel to the first rotation direction, the fourth rotating rod 20 should be set to be parallel to the first rotating rod 7 in the initial configuration of the parallel mechanism driven by the inner and outer pairs in a combined manner.
In one implementation, as shown in fig. 3, the ball pair 27 includes a fixed seat 23 and a movable member 26 movably connected to the fixed seat 23; the movable piece 26 comprises a spherical part 22 and a connecting rod 21 fixedly connected with the spherical part 22, and the other end of the connecting rod 21 is fixedly connected with the second revolute pair 25; the bottom of the fixed seat 23 is fixedly connected with the movable platform 2, and the fixed seat 23 is a hemispherical groove body; the hemispherical groove body is movably connected with the spherical part 22.
Specifically, when the ball pair 27 rotates, it corresponds to the relative movement between the fixed seat 23 and the movable member 26. Since the ball pair 27 can rotate in multiple directions, it can move well in accordance with the moving directions of other driven members.
In order to realize the stable connection between the fourth rotating rod 20 and the ball pair 27, in an implementation manner, one end of the connecting rod 21 is provided with a circular ring structure, and the circular ring structure is used for stably sleeving the moving member 26 on the middle portion of the fourth rotating rod 20. Specifically, the inner peripheral surface of the annular structure is fixedly connected to the fourth rotating rod 20, and the outer peripheral surface of the annular structure is fixedly connected to one end of the connecting rod 21, so that the fourth rotating rod 20 is stably connected to the ball pair 27.
In order to increase the overall structural strength of the third branch 5, in one implementation, the movable element 26 and the fourth rotating lever 20 are provided as an integral structure, and the fourth U-shaped element 19 and the second sliding bar 18 are provided as an integral structure. The arrangement of the integrated structure is not only beneficial to improving the transmission efficiency, but also beneficial to simplifying the installation steps during installation.
In order to improve the stability of the parallel mechanism driven by the inner and outer pairs in a combined manner, in one implementation mode, the area of the movable plane is set to be smaller than that of the base 1. The stability of the object is related to the center of gravity of the object and the base area of the support surface, and the larger the base area of the support surface is, the more stable the object is without changing the center of gravity. Because the base 1 plays a role of stable support in the parallel mechanism driven by the inner pair and the outer pair in a combined manner, when the area of the base 1 is larger than that of the moving plane, the parallel mechanism driven by the inner pair and the outer pair in a combined manner is in a relatively stable state. According to the use requirement of a user, the movable plane and the base 1 can be set to be in various shapes such as a circle, a triangle, a trapezoid and the like. In one implementation, the movable plane and the base 1 are shaped as an isosceles trapezoid and are arranged in the same direction. In order to keep the stability of the parallel mechanism driven by the inner and outer pairs in a combined manner, the first branch chain 3 and the second branch chain 4 are arranged at two ends of the lower bottom of the isosceles trapezoid, and the third branch chain 5 is arranged at the upper bottom and is positioned on a perpendicular bisector of a line segment taking the bottoms of the first branch chain 3 and the second branch chain 4 as endpoints. So that the first branch chain 3, the second branch chain 4 and the third branch chain 5 are distributed in a T shape, and the motion of the dynamic plane is supported more stably.
In summary, the present invention discloses an internal and external pair jointly driven parallel mechanism, which comprises: the device comprises a base, a movable platform, a first branched chain, a second branched chain and a third branched chain; the first branched chain and the second branched chain have the same structure and respectively comprise a universal pair connected with the base, a first revolute pair connected with the movable platform and a first moving pair connected with the universal pair and the first revolute pair; the third branched chain comprises a second moving pair connected with the base, a ball pair connected with the movable platform, and a second rotating pair connected with the ball pair and the second moving pair; the first moving pair and the second moving pair are driving pairs. According to the parallel mechanism, the first moving pair serving as the middle rod piece and the second moving pair directly connected with the base are both set as driving pairs, so that the integral rigidity of the parallel mechanism is effectively improved.
It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.
Claims (10)
1. The utility model provides an interior outer pair combined drive's parallel mechanism which characterized in that, interior outer pair combined drive's parallel mechanism includes: the base, the movable platform opposite to the base, and a first branched chain, a second branched chain and a third branched chain which are used for connecting the base and the movable platform; the third branched chain is arranged between the first branched chain and the second branched chain;
the first branched chain and the second branched chain have the same structure and respectively comprise a universal pair, a first moving pair and a first rotating pair; the universal pair is connected with the base; the first rotating pair is connected with the movable platform; the first sliding pair is connected with the universal pair and the first rotating pair;
the third branched chain comprises a second sliding pair, a second rotating pair and a ball pair; the second sliding pair is connected with the base; the ball pair is connected with the movable platform; the second revolute pair is connected with the ball pair and the second sliding pair;
the first moving pair and the second moving pair are driving pairs.
2. The inner and outer pair combination driven parallel mechanism according to claim 1, wherein the direction of rotation of the universal pair comprises a first direction of rotation and a second direction of rotation perpendicular to the first direction of rotation;
the rotating direction of the first rotating pair is parallel to the second rotating direction;
the rotation direction of the second revolute pair is parallel to the first rotation direction.
3. The co-driven internal and external pair parallel mechanism according to claim 2, wherein the gimbal pair comprises a first U-shaped member, a second U-shaped member movably connected to the first U-shaped member;
the first U-shaped part is fixedly connected with the base, a first through hole, a second through hole and a first rotating rod movably connected with the first through hole and the second through hole are formed in the upper end of the first U-shaped part, and the first through hole and the second through hole are oppositely arranged;
the second U-shaped piece is fixedly connected with the first moving pair; a third through hole, a fourth through hole and a second rotating rod movably connected with the third through hole and the fourth through hole are formed in the upper end of the second U-shaped part, and the third through hole and the fourth through hole are arranged oppositely; the first rotating rod is perpendicular to and fixedly connected with the second rotating rod;
when the first rotating rod rotates relative to the first through hole and the second through hole, the universal pair rotates in the first rotating direction;
when the second rotating rod rotates relative to the third through hole and the fourth through hole, the universal pair rotates in the second rotating direction.
4. The inner and outer pair combined driven parallel mechanism according to claim 3, wherein the first moving pair comprises a first sliding chute and a first sliding rod in sliding connection with the first sliding chute;
the first sliding groove is fixedly connected with the universal pair, and the first sliding rod is fixedly connected with the first rotating pair; the shape of the opening end of the first sliding groove is matched with the shape of the first sliding rod, and the first sliding groove is sleeved on the first sliding rod.
5. The internal and external pair combination driven parallel mechanism according to claim 4, wherein the first rotating pair comprises a third U-shaped member, a third rotating rod rotatably connected with the third U-shaped member;
the third U-shaped part is connected with the movable platform, a fifth through hole and a sixth through hole are formed in the upper end of the third U-shaped part, and the fifth through hole and the sixth through hole are arranged oppositely; the third rotating rod is movably connected with the fifth through hole and the sixth through hole; the third rotating rod is perpendicular to and fixedly connected with the first sliding pair; the rotating direction of the third rotating rod is the rotating direction of the first rotating pair.
6. The inner and outer pair combined driven parallel mechanism according to claim 2, wherein the second moving pair comprises a second sliding chute and a second sliding rod slidably connected with the second sliding chute;
the second sliding groove is fixedly connected with the base, and the second sliding rod is fixedly connected with the second revolute pair; the shape of the opening end of the second sliding chute is matched with the shape of the second sliding rod, and the second sliding chute is sleeved on the second sliding rod.
7. The internal and external pair combination driven parallel mechanism according to claim 6, wherein the second rotating pair comprises a fourth U-shaped member and a fourth rotating rod rotatably connected with the fourth U-shaped member;
the fourth U-shaped piece is fixedly connected with the second moving pair; a seventh through hole and an eighth through hole are formed in the upper end of the fourth U-shaped part, and the seventh through hole and the eighth through hole are arranged oppositely; the fourth rotating rod is movably connected with the seventh through hole and the eighth through hole; the fourth rotating rod is fixedly connected with the ball pair; the rotation direction of the fourth rotating rod is the rotation direction of the second rotating pair.
8. The inner and outer pair combined driven parallel mechanism according to claim 6, wherein the ball pair comprises a fixed seat and a movable member movably connected with the fixed seat;
the movable piece comprises a spherical part and a connecting rod fixedly connected with the spherical part, and the other end of the connecting rod is fixedly connected with the second revolute pair;
the bottom of the fixed seat is fixedly connected with the movable platform, and the fixed seat is a hemispherical groove body; the hemispherical groove body is movably connected with the spherical part.
9. The inner and outer pair combined driven parallel mechanism according to claim 1, wherein the movable platform has an area smaller than that of the base.
10. The internal and external pair combined drive parallel mechanism according to claim 1, wherein the third branched chain is arranged on a perpendicular bisector of a line segment with the bottoms of the first branched chain and the second branched chain as end points.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010954692.9A CN112192546A (en) | 2020-09-11 | 2020-09-11 | Parallel mechanism driven by inner pair and outer pair in combined mode |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010954692.9A CN112192546A (en) | 2020-09-11 | 2020-09-11 | Parallel mechanism driven by inner pair and outer pair in combined mode |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113478464A (en) * | 2021-07-22 | 2021-10-08 | 中北大学 | Parallel bionic moving platform with adjustable gravity center |
| CN114701580A (en) * | 2022-03-22 | 2022-07-05 | 沈阳工业大学 | Omnidirectional motion multi-foot wall-climbing unmanned system for maintaining outer surface of wind turbine generator |
-
2020
- 2020-09-11 CN CN202010954692.9A patent/CN112192546A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113478464A (en) * | 2021-07-22 | 2021-10-08 | 中北大学 | Parallel bionic moving platform with adjustable gravity center |
| CN114701580A (en) * | 2022-03-22 | 2022-07-05 | 沈阳工业大学 | Omnidirectional motion multi-foot wall-climbing unmanned system for maintaining outer surface of wind turbine generator |
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