Single degree of freedom n-reverse four-bar kinematic chain and grasping mechanism based on the kinematic chain

Abstract

A single-degree-of-freedom N-fold reverse four-bar linkage and a gripping mechanism based on this linkage belong to the technical field of gripping systems. This invention solves the problem in existing technologies of lacking a stable gripping mechanism for structures with long lengths such as cables and pipes, and the poor stability and limited envelope range of existing gripping mechanisms. It includes a drive rod and N sets of basic linkages arranged sequentially from end to end. The drive rod is a two-link assembly, and each basic linkage includes a first link and a second link, both of which are three-link assemblies. The absence of degree-of-freedom redundancy results in better system stability and controllability. The N sets of basic linkages can be continuously extended according to the above connection method. While maintaining the reverse four-bar structure, the length of the kinematic chain can be gradually increased to achieve a larger envelope range.

Description

Technical Field

[0001] This invention relates to a single-degree-of-freedom N-fold reverse four-bar linkage and a gripping mechanism based on the linkage, belonging to the field of gripping system technology. Background Technology

[0002] In the context of industrial automation and intelligent manufacturing, gripping systems are increasingly widely used, especially in the power, communications, and manufacturing industries, where the handling and management of cables and pipes are crucial aspects of daily operations. These objects typically have considerable length and specific shapes, making it difficult for traditional gripping mechanisms to achieve efficient and stable gripping, leading to reduced productivity and increased safety hazards. Existing gripping robots are mostly complex in structure and generally require multiple bionic finger structures to cooperate in gripping operations, resulting in redundant degrees of freedom and poor overall stability and difficulty in control. Furthermore, existing kinematic chains that achieve gripping through envelope characteristics generally have specific kinematic chain length requirements, which also limits their envelope range. Summary of the Invention

[0003] The present invention aims to solve the above-mentioned technical problems and provides a single-degree-of-freedom N-fold reverse four-bar linkage and a gripping mechanism based on the linkage.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: A single-degree-of-freedom N-fold reverse four-bar linkage includes a drive rod and N sets of basic linkages arranged sequentially from end to end. The drive rod is a two-link assembly. Each set of basic linkages includes a first link and a second link. Both the first link and the second link are three-link assemblies. The drive rod is connected to the right connection position 2 of the second link in the first set of basic linkages, the middle connection position 1 of the first link and the middle connection position 2 of the second link, the left connection position 1 of the first link in each set of basic linkages and the right connection position 1 of the first link in the next set of basic linkages, and the left connection position 2 of the second link in each set of basic linkages and the right connection position 2 of the second link in the next set of basic linkages, all of which are revolute joint connections.

[0005] Furthermore, the structure of rod one and rod two is the same.

[0006] Furthermore, both rod one and rod two have an L-shaped structure.

[0007] Furthermore, each rotating joint is equipped with a bearing.

[0008] Furthermore, the bearing is a thrust bearing.

[0009] A gripping mechanism based on the above-mentioned kinematic chain includes a frame, a servo motor, and a single-degree-of-freedom N-fold reverse four-bar kinematic chain. The servo motor is mounted on the frame, and the other end of the drive rod is fixedly mounted on the output end of the servo motor. The right connecting position of the first basic linkage is rotatably connected to the frame.

[0010] Furthermore, N=5.

[0011] Compared with the prior art, the present invention has the following advantages: The single-degree-of-freedom N-fold reverse four-bar linkage of the present invention consists of only three types of links: the drive link, link one, and link two. Compared with the prior art, this greatly simplifies the structural composition.

[0012] This invention employs a single-degree-of-freedom finger structure with no degree-of-freedom redundancy, resulting in better system stability and ease of control.

[0013] The N basic linkages can be extended continuously in the above connection method. That is, the kinematic chain composed of this linkage structure and connection method has the characteristics of infinite extension and expansion. No matter how many basic linkages are connected, the entire kinematic chain still maintains a single degree of freedom.

[0014] This invention can gradually increase the length of the kinematic chain or add additional motion modules while maintaining the reverse four-bar structure. By expanding the kinematic chain, a larger envelope range can be achieved, and its overall envelope characteristics remain unchanged regardless of the length of the kinematic chain.

[0015] By connecting the drive rod to the servo motor, the entire single-degree-of-freedom N-fold reverse four-bar linkage is directly driven to gradually wrap around and envelop the object to be grasped. In actual use, the frame can also be connected to a robotic arm for operation, making the single-degree-of-freedom grasping mechanism applicable to a wider range of scenarios.

[0016] The object to be grabbed is a structure such as a pipe or cable.

[0017] When the gripping mechanism of the present invention grips, each link in the single-degree-of-freedom N-fold reverse four-bar linkage forms a contact point with the surface of the object. Each contact point is distributed along the circumference of the object to be gripped, thereby uniformly distributing pressure during gripping, reducing damage to the object, and also increasing the gripping contact area, resulting in greater friction.

[0018] The gripping mechanism of the present invention can stably grip objects of different diameters, and the gripping can be non-enclosed gripping, enclosed gripping, or wrapping gripping.

[0019] The single-degree-of-freedom gripping mechanism of this invention can stably grip objects of different diameters using a single-length kinematic chain. Its adaptability is significantly superior to existing contour grippers that can only handle objects of a single diameter, while also achieving closed-loop gripping. Attached Figure Description

[0020] Figure 1 This is a simplified schematic diagram of the first structure of the single-degree-of-freedom N-fold reverse four-bar linkage of the present invention; Figure 2 Here is a simplified structural diagram of rod one; Figure 3 The diagram shows a simplified structural representation of rod two (the dashed lines are for illustrative purposes only and are intended to distinguish it from the structure of rod one). Figure 4 This is a simplified schematic diagram of the basic linkage structure; Figure 5 This is a simplified schematic diagram (complete connection) of the second structure of the single-degree-of-freedom N-fold reverse four-bar kinematic chain of the present invention. Figure 6 This is a schematic diagram of a single-degree-of-freedom five-fold reverse linkage. Figure 7 This is a front view diagram of the grasping mechanism (in envelope mode); Figure 8 A schematic diagram of the first three-dimensional structure of the grasping mechanism (in the envelope state); Figure 9 This is a schematic diagram of the second three-dimensional structure of the gripping mechanism (in its extended state). Figure 10 A three-dimensional structural diagram of the gripping mechanism during wrap-around gripping; Figure 11 A three-dimensional structural diagram of the gripping mechanism during enclosed gripping; Figure 12 A three-dimensional structural diagram of the gripping mechanism gripping a 35mm pipe; Figure 13 A three-dimensional structural diagram of the gripping mechanism gripping a 40mm pipe; Figure 14 A three-dimensional structural diagram of the gripping mechanism gripping a 45mm pipe; Figure 15 This is a simplified schematic diagram of the existing reverse four-bar linkage ABCD.

[0021] In the picture: 1. Drive lever; 2. Lever 1; 21. Left connecting position 1; 22. Right connecting position 1; 23. Middle connecting position 1; 3. Lever 2; 31. Left connecting position 2; 32. Right connecting position 2; 33. Middle connecting position 2; 2-1. First link; 3-1. Second link; 2-2. Third link; 3-2. Fourth link; 2-3. Fifth link; 3-3. Sixth link; 2-4. Seventh link; 3-4. Eighth link; 2-5. Ninth link; 3-5. Tenth link; 10. Kinematic chain; 11. Frame; 12. Servo motor; 100. Object to be grasped. Detailed Implementation

[0022] Specific implementation method one: Combining Figures 1-15 This description of embodiments provides a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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.

[0023] It should be noted that the descriptions of "front," "rear," "left," "right," "inner," "outer," "left side," "right side," "upper part," "lower part," "top," and "bottom" in this invention are defined based on the orientation or positional relationships shown in the accompanying drawings. They are merely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the described structure must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0024] In the description of this invention, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] A single-degree-of-freedom N-fold reverse four-bar linkage includes a drive link 1 and N sets of basic links arranged sequentially from end to end. The drive link 1 is a two-link system. Each set of basic links includes a first link 2 and a second link 3. Both the first link 2 and the second link 3 are three-link systems. The drive link 1 is connected to the right connection position 32 of the second link 3 in the first set of basic links, the middle connection position 23 of the first link 2 and the middle connection position 33 of the second link 3, the left connection position 21 of the first link 2 in each set of basic links and the right connection position 22 of the first link 2 in the next set of basic links, and the left connection position 31 of the second link 3 in each set of basic links and the right connection position 32 of the second link 3 in the next set of basic links, all of which are revolute joint connections.

[0026] The single-degree-of-freedom N-fold reverse four-bar linkage of the present invention consists of only three types of links: drive link 1, link 1 2, and link 2 3. Compared with the prior art, it greatly simplifies the structural composition.

[0027] This invention employs a single-degree-of-freedom finger structure with no degree-of-freedom redundancy, resulting in better system stability and ease of control.

[0028] The N basic linkages can be extended continuously in the above connection method. That is, the kinematic chain composed of this linkage structure and connection method has the characteristics of infinite extension and expansion. No matter how many basic linkages are connected, the entire kinematic chain still maintains a single degree of freedom.

[0029] This invention can maintain the reverse four-bar structure ABCD (such as...) Figure 15 Based on the above, by gradually increasing the length of the kinematic chain or adding additional kinematic modules, a larger envelope range can be achieved by expanding the kinematic chain, and its overall envelope characteristics remain unchanged regardless of the length of the kinematic chain.

[0030] The structures of rod 1 (2) and rod 2 (3) can be the same or different.

[0031] This invention presents a single-degree-of-freedom N-fold reverse four-bar linkage, innovatively designed to meet the specific needs of industrial applications for cable and conduit handling. By simplifying the structure, optimizing control, and improving gripping efficiency, this technology can play a significant role in modern manufacturing and automation processes, driving the intelligent upgrading of related industries.

[0032] The structure of rod 1 (2) and rod 2 (3) is the same.

[0033] Both rod 2 and rod 3 are L-shaped. With this design, the L-shaped corner position is the intermediate connection point.

[0034] Each rotating joint is equipped with a bearing. With this design, the rotating joints between the rods are connected by bearings and shafts, and the two ends of the shaft are secured with shaft end retaining rings. Any two contacting rods can directly pass through the bearings to reduce friction.

[0035] The bearing is a thrust bearing. This design further reduces friction between the two connected rods.

[0036] A gripping mechanism based on the above-mentioned kinematic chain includes a frame 11, a servo motor 12, and a single-degree-of-freedom N-fold reverse four-bar kinematic chain 10. The servo motor 12 is mounted on the frame 11, and the other end of the drive rod 1 is fixedly mounted on the output end of the servo motor 12. The right connection position 22 of the first basic linkage 2 is rotatably connected to the frame 11.

[0037] By connecting the drive rod 1 to the servo motor 12, the entire single-degree-of-freedom N-fold reverse four-bar linkage is directly driven to gradually wrap around and envelop the object 100 to be grasped. In actual use, the frame 11 can also be connected to the robotic arm for operation according to actual needs, making the entire single-degree-of-freedom grasping mechanism applicable to a wider range of scenarios.

[0038] The object to be grabbed, 100, refers to the pipe or cable structure to be grabbed.

[0039] When the gripping mechanism of the present invention grips, each link in the single-degree-of-freedom N-fold reverse four-bar linkage forms a contact point with the surface of the object. Each contact point is distributed along the 100 circumference of the object to be gripped, thereby uniformly distributing pressure during gripping, reducing damage to the object, and also increasing the gripping contact area, resulting in greater friction.

[0040] The gripping mechanism of the present invention can stably grip objects 100 of different diameters. The gripping can be non-enclosed, enclosed, or wrapping, for example: When the diameter of the object to be grasped 100 is large, the single-degree-of-freedom N-fold reverse four-bar linkage completely surrounds the object to be grasped 100 (e.g. Figure 11 As shown), this ensures that the object to be grasped 100 is firmly fixed during grasping, avoiding the slippage and detachment problems that easily occur in existing open grasping mechanisms (i.e., the single-degree-of-freedom N-fold reverse four-bar linkage is a closed loop. Alternatively, the single-degree-of-freedom N-fold reverse four-bar linkage can enclose the object to be grasped 100 but not completely surround it; that is, the single-degree-of-freedom N-fold reverse four-bar linkage is not a closed loop, and there is a certain gap between the first and last ends. However, along the circumferential direction of the object to be grasped 100, the straight-line distance between each two adjacent contact points formed by the single-degree-of-freedom N-fold reverse four-bar linkage is less than the radius or three-quarters of the diameter of the object to be grasped 100, thus ensuring that there will be no slippage or detachment problems during grasping). When the diameter of the object to be grasped is relatively small (e.g., 100), it can be enveloped by wrapping around it. Figure 10As shown, this wrapping enveloping method creates more contact points with the object's surface, allowing for a more even distribution of pressure during gripping and further reducing damage to the object. This design increases the gripping contact area and correspondingly increases friction during gripping.

[0041] The single-degree-of-freedom gripping mechanism of this invention can stably grip objects 100 of different diameters using a single-degree-of-freedom N-fold reverse four-bar linkage 10 of a single length. For example, a gripping mechanism based on a single-degree-of-freedom five-fold reverse four-bar linkage can be used to stably grip 35mm, 40mm, and 45mm pipes respectively. When used to grip a 35mm pipe (e.g.) Figure 12 As shown), due to the small pipe diameter, the kinetic chain wraps around the pipe in a spiral manner; when used for gripping a 40mm pipe (as shown), Figure 13 As shown), the kinetic chain wraps around the pipe in a spiral manner, but the contact points between the kinetic chain and the pipe are less than 35mm of pipe; when used for gripping 45mm pipes (as shown), Figure 14 As shown in the figure, due to the large diameter of the pipe, the kinetic chain is wrapped around the pipe in a fully enclosed manner.

[0042] The gripping mechanism of the present invention has significantly better adaptability than the existing contour grippers that can only handle objects of a single diameter, and can achieve closed gripping of contour grippers.

[0043] N=5. This means selecting five basic linkage groups to form a single-degree-of-freedom five-fold reverse four-bar linkage, or a single-degree-of-freedom five-fold reverse link. The linkage consists of a drive link 1 and links one through ten. Drive link 1 is a two-link system, and links one through ten are all three-link systems. Links 2-1 and 3-1 form the first basic linkage group; links 2-2 and 3-2 form the second basic linkage group; links 2-3 and 3-3 form the third basic linkage group; links 2-4 and 3-4 form the fourth basic linkage group; and links 2-5 and 3-5 form the fifth basic linkage group. Preferably, ... Figure 6 As shown, all links in this five-bar linkage, except for the drive link 1, have identical structures.

[0044] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A single-degree-of-freedom N-fold reverse four-bar linkage, characterized in that: The device includes a drive rod (1) and N sets of basic rods arranged in sequence. The drive rod (1) is a two-pair rod. Each set of basic rods includes rod one (2) and rod two (3). Both rod one (2) and rod two (3) are three-pair rods. The drive rod (1) is connected to the right connecting position two (32) of rod two (3) in the first set of basic rods, the middle connecting position one (23) of rod one (2) and the middle connecting position two (33) of rod two (3), the left connecting position one (21) of rod one (2) in each set of basic rods and the right connecting position one (22) of rod one (2) in the next set of basic rods, and the left connecting position two (31) of rod two (3) in each set of basic rods and the right connecting position two (32) of rod two (3) in the next set of basic rods. Each rotating pair is equipped with a thrust bearing.

2. The single-degree-of-freedom N-fold reverse four-bar linkage according to claim 1, characterized in that: The structure of rod one (2) and rod two (3) is the same.

3. The single-degree-of-freedom N-fold reverse four-bar linkage according to claim 1, characterized in that: Both rod one (2) and rod two (3) are L-shaped structures.

4. A gripping mechanism based on a single-degree-of-freedom N-fold reverse four-bar linkage as described in any one of claims 1 to 3, characterized in that: It includes a frame (11), a servo motor (12) and a single-degree-of-freedom N-fold reverse four-bar linkage (10). The servo motor (12) is mounted on the frame (11), and the other end of the drive rod (1) is fixed to the output end of the servo motor (12). The right connection position (22) of the first basic linkage (2) is rotatably connected to the frame (11).

5. The gripping mechanism according to claim 4, characterized in that: N=5。

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