Coaxial equidistant linear drive joint

Abstract

The invention discloses a coaxial equidistant linear drive joint, which relates to the technical field of manipulators, and comprises a finger tip, a first joint structure, a second joint structure, a third joint structure and a base, the finger tip is connected with one end of the first joint structure, and the other end of the first joint structure is connected with one end of the second joint structure; the other end of the second joint structure is connected with the third joint structure; and the third joint structure is connected with the base. The driving joint can be miniaturized or large, the long-distance energy transmission pipeline can enable the driving joint to have enough force to execute a driving task, meanwhile, the size of the driving joint can be made smaller and lighter under the permissible of materials, and due to the fact that the driving joint is used to be separated from a driving source, the size of the driving joint can be reduced. Therefore, insufficient energy caused by too small size of the driving joint can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of robotic arms, and more particularly to a coaxial equidistant wire-driven joint. Background Art

[0002] Robots have always been cutting-edge technologies developed in this century. In the research of robots, robotic fingers are a research difficulty.

[0003] After retrieval, the Chinese patent document with the authorization announcement number CN210041673U discloses a piezoelectric motor support for a robotic finger joint, which includes a pair of rotors, a pair of stators, a pair of piezoelectric ceramic sheets, three electrode sheets, and a shaft system assembly. The shaft system assembly includes a rotating shaft, bearings, and a snap ring. The piezoelectric ceramic sheets and the electrode sheets are sequentially sleeved in the middle of the rotating shaft in the structure form of electrode sheet, piezoelectric ceramic sheet, electrode sheet, piezoelectric ceramic sheet, electrode sheet, and are pressed between a pair of stators by the stators. A pair of rotors are rotatably sleeved on the rotating shaft through bearings, and the inner end surfaces of the rotors are attached to the outer end surfaces of the stators. The patent has a simple structure, is easy to manufacture and assemble, does not interfere with the operation of the robotic finger and the piezoelectric motor, and can be used in robots.

[0004] Based on the retrieval and the existing technology, it is found that: for current bionic robotic hands, the movement of robot joints basically relies on motors directly placed at each joint position for driving. In this driving mode, due to the large size of the motors and the small size of the driving joints, it is impossible to place large-sized motors on small-sized joints, so that the motor direct drive joints cannot be miniaturized. If the motors are made smaller, it will cause serious insufficient power of the motors to drive the movement of small joints and cannot obtain effective load output. The traditional driving mode basically uses a single wire to drive multiple joints to move simultaneously, which will cause interference between joints and make the joints unable to operate independently without interference. If multiple wires are used to drive multiple joints separately, it will cause serious interlocking phenomena during the operation of the joints, resulting in the joints being unable to move normally or being able to move but with excessive energy loss due to interference between joints and very serious mechanical wear. Summary of the Invention

[0005] The purpose of the present invention is to provide a coaxial equidistant wire-driven joint to solve the problems raised in the above background art.

[0006] The technical solution of the present invention is: a coaxial equidistant wire-driven joint, including a fingertip, a first joint structure, a second joint structure, a third joint structure, and a base. The outer contours of the first joint structure and the second joint structure are both strip-shaped and can both be bent by 90 degrees; The fingertip is connected to one end of the first joint structure, and the other end of the first joint structure is connected to one end of the second joint structure; The other end of the second joint structure is connected to the third joint structure; The third joint structure is connected to the base; The first joint structure, the second joint structure and the third joint structure are jointly connected to a wire drive mechanism.

[0007] Preferably, the first joint structure includes a first front joint and a first middle joint, and the second joint structure includes a second front joint and a second middle joint; one side of the first front joint is a square plate, and a long plate with a semi-circular end bulges outwards at the middle position of one side plate surface of the square plate. The other side plate surface of the square plate of the first front joint is fixed to the fingertip. A circular wire groove for restricting the position of the wire is provided at the middle position of the semi-circular end of the first front joint. An arc wire hole connected to the circular wire groove and coaxially arranged is provided inside the long plate of the first front joint. Two second wire passing holes are provided on the plate surface of the first front joint, respectively located on both sides of the long plate, and the central axes of the second wire passing holes are coplanar with the central axis of the semi-circular end of the long plate. The outer structures of the first front joint, the second front joint and the third joint structure are the same.

[0008] Preferably, the first joint structure further includes a second middle joint, and the second joint structure further includes a second middle joint. Two first wire passing holes are provided inside the first middle joint, and the central axes of the first wire passing holes are both located on the middle surface of the first middle joint. The first middle joint and the second middle joint have the same specifications.

[0009] Preferably, cylinders coaxially arranged with its semi-circular end are fixed on both sides of the long plate, and the second wire passing holes penetrate through the cylinders. First finger plates, second finger plates and third finger plates are respectively fixed on the outsides of the first middle joint, the second middle joint and the base. Rotation holes are provided on the outsides of the first finger plate, the second finger plate and the third finger plate. The cylinders on the first front joint are rotatably installed in the rotation holes on the first finger plate, the cylinders on the second front joint are rotatably installed in the rotation holes on the second finger plate, and the cylinders on the third joint structure are rotatably installed in the rotation holes on the third finger plate.

[0010] Preferably, the first joint structure further includes a first rear joint. The two ends of the first rear joint are respectively fixed to the first middle joint and the second front joint. Two first guiding wire holes are provided inside the first rear joint, and the two ends of the first guiding wire holes are respectively located at the two ends of the first rear joint. One ends of the two first guiding wire holes are coaxially arranged with the two first wire passing holes on the first middle joint respectively, and one ends of the two second guiding wire holes are coaxially arranged with the two second wire passing holes on the second front joint respectively.

[0011] Preferably, the second joint structure further includes a second rear joint. Two third wire threading holes are provided inside the second rear joint, and two second guiding wire holes are provided inside the second rear joint. One ends of the two second guiding wire holes are respectively communicated with the two third wire threading holes and the other ends extend out of the second rear joint. Two ends of the second rear joint are respectively fixed to the second middle joint and the third joint structure. Two fourth wire threading holes are provided on the inner side wall of the second middle joint. The two third wire threading holes are coaxially arranged with the two fourth wire threading holes on the second middle joint, and the two third wire threading holes are coaxially arranged with the two second wire threading holes on the third joint structure. One ends of the two second guiding wire holes are respectively coaxially arranged with the two first wire threading holes on the second middle joint.

[0012] Preferably, the wire driving mechanism includes a first driving wire. The middle end of the first driving wire is fixed in the arc wire hole of the first front joint and within the arc wire hole. Two ends of the first driving wire respectively pass through the two first wire threading holes on the first middle joint, the two guiding wire holes on the first rear joint, the two second wire threading holes on the second front joint, the fourth wire threading holes on the second middle joint, the two third wire threading holes on the second rear joint, and the two second wire threading holes on the third joint structure. First driving tubes are sleeved on both ends of the first driving wire.

[0013] Preferably, the wire driving mechanism further includes a second driving wire. The middle end of the second driving wire is located in the arc wire hole of the second front joint and fixed within the arc wire hole. Two ends of the second driving wire respectively pass through the fourth wire threading holes on the second middle joint, the two second guiding wire holes on the second rear joint, and the two second wire threading holes on the third joint structure. Second driving tubes are sleeved on both ends of the second driving wire.

[0014] Preferably, the wire driving mechanism further includes a third driving wire. The middle end of the third driving wire is located in the arc wire hole of the third joint structure and fixed within the arc wire hole. Third driving tubes are sleeved on both ends of the third driving wire.

[0015] Preferably, a wire moving groove is provided on one side of the first wire threading hole.

[0016] The present invention provides a coaxial and equidistant wire-driven joint through improvement. Compared with the prior art, it has the following improvements and advantages: First: The present invention can miniaturize or magnify the driving joint. The long-distance energy transmission pipeline can enable the driving joint to have sufficient force to perform the driving task. At the same time, the volume of the driving joint can be made smaller and lighter under the allowable materials. Since the driving joint is separated from the driving source, the driving joint will not have insufficient energy due to its too small volume. Secondly, the present invention can allow large mechanical equipment to obtain sufficient energy, and can avoid the traditional driving method of installing the driving source at the joint movable position, which makes the joint unable to be miniaturized or requires a heavier driving source to obtain a larger driving torque, thereby causing the joint gravity to increase the driving weight on the original weight invisibly, resulting in the need to install a larger and heavier driving source on the driving joint in order to obtain greater power. The increase in the volume and weight of the driving source causes the driving joint to become larger and heavier, and in order to drive a larger and heavier joint, the weight of the driving source must be increased, resulting in a vicious cycle. The present invention uses the separation technology of the driving joint, the driving source, and the energy transmission pipeline to reduce the weight of the driving joint to the greatest extent, so as to obtain enough power to allow the driving joint to really move. When the driving joint is not strong enough, the driving source can be continuously amplified without affecting the original weight and size of the driving joint. Therefore, no matter how large and heavy the driving joint is, it can be moved by adjusting the output energy of the driving source remotely under the permission of the material. This makes it possible to realize various driving devices that require driving conditions, such as large mechanical equipment, small nano robots, or humanoid mechas. Secondly, the present invention uses the coaxial and isometric principle to reduce the motion interference between joints to a minimum. Theoretically, with this technology, as long as the material meets the requirements, the joints can be made small enough or large enough, and the energy output will not be affected while the joint movements do not interfere with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the finger joint structure of the present invention; Figure 2 It is a schematic diagram of the three-dimensional structure of the first joint structure, the second joint structure, the third joint structure and the wire drive mechanism of the present invention; Figure 3 This is a schematic diagram of the installation of the first driving line of the present invention; Figure 4 It is a perspective view of the first joint structure, the second joint structure and the third joint structure of the present invention; Figure 5 This is a schematic diagram of the installation of the second driving line of the present invention; Figure 6 are perspective views of the second joint structure and the third joint structure of the present invention; Figure 7 Schematic diagram of the installation of the third driving line of the present invention; Figure 8 Perspective view of the third joint structure of the present invention; Figure 9 is Figure 4 Cross-sectional view of; Figure 10 is Figure 9 Enlarged structural schematic diagram at location A of; Figure 11 First perspective three-dimensional structural schematic diagram of the first middle joint of the present invention; Figure 12 Second perspective three-dimensional structural schematic diagram of the first middle joint of the present invention; Figure 13 Perspective view of the first middle joint of the present invention; Figure 14 First perspective three-dimensional structural schematic diagram of the first rear joint of the present invention; Figure 15 Second perspective three-dimensional structural schematic diagram of the first rear joint of the present invention; Figure 16 Perspective view of the first rear joint of the present invention; Figure 17 First perspective three-dimensional structural schematic diagram of the first front joint of the present invention; Figure 18 Second perspective three-dimensional structural schematic diagram of the first front joint of the present invention; Figure 19 Perspective view of the first front joint of the present invention; Figure 20 First perspective three-dimensional structural schematic diagram of the second rear joint of the present invention; Figure 21 Second perspective three-dimensional structural schematic diagram of the second rear joint of the present invention; Figure 22 Perspective view of the second rear joint of the present invention; Figure 23 First perspective three-dimensional structural schematic diagram of the second middle joint of the present invention; Figure 24 Second perspective three-dimensional structural schematic diagram of the second middle joint of the present invention; Figure 25 Perspective view of the second middle joint of the present invention; Figure 26 Another joint mode diagram of the finger joint of the present invention.

[0019] Reference numerals: 1. Finger tip; 2. First finger plate; 3. Second finger plate; 4. Third finger plate; 5. Base; 6. First joint structure; 601. First front joint; 602. First middle joint; 603. First rear joint; 604. First threading hole; 605. Wire moving groove; 606. First guiding wire hole; 607. Arc wire hole; 608. Annular wire groove; 609. Cylinder; 610. Second threading hole; 7. Second joint structure; 701. Second front joint; 702. Second middle joint; 703. Second rear joint; 704. Third threading hole; 705. Second guiding wire hole; 706. Fourth threading hole; 8. Third joint structure; 9. First driving wire; 10. First driving tube; 11. Third driving wire; 12. Third driving tube; 13. Second driving wire; 14. Second driving tube. Detailed implementation mode

[0020] The present invention will be described in detail below. The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0021] The present invention provides a coaxial equidistant wire-driven joint by improvement. The technical solution of the present invention is as follows: As Figures 1 to 25 shown, the embodiment of the present invention provides a coaxial equidistant wire-driven joint, including a finger tip 1, a first joint structure 6, a second joint structure 7, a third joint structure 8 and a base 5. The finger tip 1 is connected to one end of the first joint structure 6, and the other end of the first joint structure 6 is connected to one end of the second joint structure 7; The other end of the second joint structure 7 is connected to the third joint structure 8; The third joint structure 8 is connected to the base; The first joint structure, the second joint structure 7 and the third joint structure 8 are jointly connected with a wire-driven mechanism; From the above brief description, it can be seen that each joint of the present invention is independently provided, and at the same time, the wire-driven mechanisms used to drive the work of each joint are independently arranged outside, so that the whole mechanical finger can be lightweight.

[0022] Specifically, in combination with the attached Figures 11 - 25As shown, the first joint structure 6 includes a first front joint 601 and a first middle joint 602, and the second joint structure 7 includes a second front joint 701 and a second middle joint 702; one side of the first front joint 601 is a square plate, and a long plate with a semi-circular end bulges outwards at the middle position of one side plate surface of the square plate. The other side plate surface of the square plate of the first front joint 601 is fixed to the fingertip 1. An annular wire groove 608 for restricting the wire position is provided at the middle position of the semi-circular end of the first front joint 601. An arc-shaped wire hole 607 that is connected to the annular wire groove 608 and coaxially arranged is provided inside the long plate of the first front joint 601. Two second wire passing holes 610 are provided on the plate surface of the first front joint 601 and are respectively located on both sides of the long plate, and the central axis of the second wire passing hole 610 is coplanar with the central axis of the semi-circular end of the long plate. The outer structures of the first front joint 601, the second front joint 701, and the third joint structure 8 are the same. The first joint structure 6 further includes the second middle joint 702, and the second joint structure 7 also includes the second middle joint 702. Two first wire passing holes 604 are provided inside the first middle joint 602, and the central axes of the first wire passing holes 604 are both located on the middle surface of the first middle joint 602. The first middle joint 602 and the second middle joint 702 have the same specifications. Cylinders 609 coaxial with its semi-circular end are fixed on both sides of the long plate, and the second wire passing hole 610 penetrates through the cylinder 609. First finger plates 2, second finger plates 3, and third finger plates 4 are respectively fixed to the outsides of the first middle joint 602, the second middle joint 702, and the base 5. Rotation holes are provided on the outsides of the first finger plate 2, the second finger plate 3, and the third finger plate 4. The cylinder 609 on the first front joint 601 is rotatably installed in the rotation hole on the first finger plate 2. The cylinder 609 on the second front joint 701 is rotatably installed in the rotation hole on the second finger plate 3. The cylinder 609 on the third joint structure 8 is rotatably installed in the rotation hole on the third finger plate 4. The first joint structure 6 further includes a first rear joint 603. The two ends of the first rear joint 603 are respectively fixed to the first middle joint 602 and the second front joint 701. Two first guiding wire holes 606 are provided inside the first rear joint 603, and the two ends of the first guiding wire holes 606 are respectively located at the two ends of the first rear joint 603. One ends of the two first guiding wire holes 606 are coaxially arranged with the two first wire passing holes 604 on the first middle joint 602 respectively. One ends of the two second guiding wire holes 705 are coaxially arranged with the two second wire passing holes 610 on the second front joint 701 respectively. The second joint structure 7 further includes a second rear joint 703. Two third wire passing holes 704 are provided inside the second rear joint 703. Two second guiding wire holes 705 are provided inside the second rear joint 703. One ends of the two second guiding wire holes 705 are respectively connected to the two third wire passing holes 704 and the other ends extend out of the second rear joint 703. The two ends of the second rear joint 703 are respectively fixed to the second middle joint 702 and the third joint structure 8.On the inner wall of the second middle joint 702, two fourth wire threading holes 706 are provided. The two third wire threading holes 704 are coaxially arranged with the two fourth wire threading holes 706 on the second middle joint 702, and the two third wire threading holes 704 are coaxially arranged with the two second wire threading holes 610 on the third joint structure 8. One ends of the two second guiding wire holes 705 are respectively coaxially arranged with the two first wire threading holes 604 on the second middle joint 702.,

[0023] The first joint structure 6, the second joint structure 7 and the third joint structure 8 as described above are described as follows: First, the arrangement of each wire hole is for the convenience of threading the driving wires of the following wire driving mechanism. At the same time, the distribution mode of each wire hole is different, so that each driving wire can be kept as taut and independent as possible to work, achieving non-interference with each other and avoiding the occurrence of production line problems; Second, within the allowable range of materials, each of the three joint structures, namely the first joint structure 6, the second joint structure 7 and the third joint structure 8, can be made small or large, and each joint is independent. Thus, the joints can focus on non-interfering movements, enabling the driving source of the following wire driving mechanism to focus on energy supply, truly achieving a driving source and energy transmission.

[0024] Specifically, in combination with the attached Figures 2 - 9 and the attached Figures 11 - 25As shown in the figure, the wire drive mechanism includes a first drive wire 9. The middle end of the first drive wire 9 is fixed within the arc-shaped wire hole 607 of the first front joint 601 and is fixed within the arc-shaped wire hole 607. The two ends of the first drive wire 9 respectively pass through two first wire-passing holes 604 on the first middle joint 602, two guiding wire holes on the first rear joint 603, two second wire-passing holes 610 on the second front joint 701, the fourth wire-passing hole 706 on the second middle joint 702, two third wire-passing holes 704 on the second rear joint 703, and two second wire-passing holes 610 on the third joint structure 8. First drive tubes 10 are sleeved on both ends of the first drive wire 9. The wire drive mechanism further includes a second drive wire 13. The middle end of the second drive wire 13 is located within the arc-shaped wire hole 607 of the second front joint 701 and is fixed within the arc-shaped wire hole 607. The two ends of the second drive wire 13 respectively pass through the fourth wire-passing hole 706 on the second middle joint 702, two second guiding wire holes 705 on the second rear joint 703, and two second wire-passing holes 610 on the third joint structure 8. Second drive tubes 14 are sleeved on both ends of the second drive wire 13. The wire drive mechanism further includes a third drive wire 11. The middle end of the third drive wire 11 is located within the arc-shaped wire hole 607 of the third joint structure 8 and is fixed within the arc-shaped wire hole 607. Third drive tubes 12 are sleeved on both ends of the third drive wire 11. It can be seen that each joint structure is respectively driven by a separate drive wire. There is no need to install a single motor at each joint rotation point, which allows each joint to be miniaturized or enlarged. The wire drive form can achieve long-distance energy transmission, enabling the drive joints to have sufficient force to perform the driving task. At the same time, the volume of the drive joints can be made smaller and lighter within the allowable range of materials. Since the drive joints are separated from the drive source, the drive joints will not have insufficient energy due to being too small in volume.

[0025] Specifically, in combination with the attached Figures 2 - 10 As shown in the figure, a wire movement groove 605 is opened on one side of the first wire-passing hole 604. It should be supplemented here that the inflection point of the wire movement groove 605 is concentric with the long board semi-circle. In this way, when each front joint rotates, it will not pull other drive wires that do not participate in the drive, ensuring that each drive wire can work relatively independently.

[0026] To supplement the above: The specific outer contour shape of each rear joint structure is not limited, in order to Figure 26For example, the second rear joint 703 is twisted, and the internal wire holes of the rear joint will also change correspondingly. The wire holes on the joint surface where the rear joint fits with the middle joint must be aligned, so as to ensure that when the second drive wire 13 passes through the corresponding middle joint, it can be parallel to the circular groove of the second front joint 608, ensuring that each joint of the finger can rotate normally. Thus, it can be seen that as long as each drive wire can be parallel to the circular groove when passing through the corresponding middle joint, each middle joint and the rear joint can change in a certain shape; The setting of the wire moving groove is related to the rotation range of each joint of the finger. Figure 9 and Figure 10 The corner of the wire moving groove is a right angle because each joint of the finger can rotate by ninety degrees, which only provides a reference. No matter how large the angle of the corner of the wire moving groove is, the inflection point of the wire moving groove must be coaxial with the cylinder; Combining the above first and second points, it can be seen that the coaxial and equidistant principle reduces the motion interference between joints to the lowest level.

[0027] Working principle: When the fingertip 1 needs to rotate, pull one end of the first drive wire 9. Since the middle end of the first drive wire 9 is fixed in the arc wire hole 607 of the first front joint 601 and fixed in the arc wire hole 607, and since the cylinder 609 on the first front joint 601 is rotatably installed in the rotation hole on the first finger plate 2, at this time, pulling one end of the first drive wire 9 can make the first front joint 601 drive the fingertip 1 to rotate around the central axis of the rotation hole on the first finger plate 2; When the first joint structure 6 needs to rotate, pull one end of the second drive wire 13. Since the middle end of the second drive wire 13 is located in the arc wire hole 607 of the second front joint 701 and fixed in the arc wire hole 607, and since the cylinder 609 on the second front joint 701 is rotatably installed in the rotation hole on the second finger plate 3, at this time, pulling one end of the second drive wire 13 can make the second front joint 701 drive the first joint structure 6 to rotate around the central axis of the rotation hole on the second finger plate 3; When the first joint structure 6 and the second joint structure 7 need to rotate, pull one end of the third drive wire 11. Since the middle end of the third drive wire 11 is located in the arc wire hole 607 of the second front joint 701 and fixed in the arc wire hole 607, and since the cylinder 609 on the third joint structure 8 is rotatably installed in the rotation hole on the third finger plate 4, at this time, pulling one end of the third drive wire 11 can make the third joint structure 8 drive the first joint structure 6 and the second joint structure 7 to rotate around the central axis of the rotation hole on the second finger plate 3; In summary, by pulling different drive lines, the entire robotic finger can perform different bending operations, eliminating the need to install individual motors at each joint rotation point. This allows each joint to be miniaturized or enlarged. The cable-driven form enables long-distance energy transmission, providing sufficient force for the driving joints to execute their tasks. Additionally, within the limits of the material used, the driving joints can be made smaller and lighter. Since the driving joints are separated from the drive source, they will not suffer from insufficient energy due to their small size.

[0028] The foregoing description enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A coaxial equidistant line-driven joint, comprising a fingertip (1), a first joint structure (6), a second joint structure (7), a third joint structure (8) and a base (5), characterized in that: The fingertip (1) is connected to one end of the first joint structure (6), and the other end of the first joint structure (6) is connected to one end of the second joint structure (7); The other end of the second joint structure (7) is connected to the third joint structure (8); The third joint structure (8) is connected to the base (5); The first joint structure, the second joint structure (7), and the third joint structure (8) are jointly connected to a wire drive mechanism.

2. The coaxial equidistant line-driven joint according to claim 1, characterized in that: The first joint structure (6) includes a first front joint (601) and a first middle joint (602), and the second joint structure (7) includes a second front joint (701) and a second middle joint (702); One side of the first front joint (601) is a square plate, and a long plate with a semi-circular end bulges outwards at the middle position of one side plate surface of the square plate. The other side plate surface of the square plate of the first front joint (601) is fixed to the fingertip (1). An annular wire groove (608) for restricting the position of the wire is provided at the middle position of the semi-circular end of the first front joint (601). An arc-shaped wire hole (607) that is communicated with the annular wire groove (608) and coaxially arranged is provided inside the long plate of the first front joint (601). Two second wire passing holes (610) are provided on the plate surface of the first front joint (601) and are respectively located on both sides of the long plate, and the central axis of the second wire passing hole (610) is coplanar with the central axis of the semi-circular end of the long plate. The outer structures of the first front joint (601), the second front joint (701), and the third joint structure (8) are the same.

3. The coaxial equidistant line-driven joint according to claim 2, wherein: The first joint structure (6) further includes a second middle joint (702), and the second joint structure (7) further includes a second middle joint (702). Two first wire passing holes (604) are provided inside the first middle joint (602), and the central axes of the first wire passing holes (604) are all located on the middle surface of the first middle joint (602). The first middle joint (602) and the second middle joint (702) have the same specifications.

4. The coaxial equidistant line-driven joint according to claim 3, characterized in that: Cylinders (609) coaxial with its semi-circular end are fixed on both sides of the long plate, and the second wire passing hole (610) penetrates through the cylinder (609). A first finger plate (2), a second finger plate (3), and a third finger plate (4) are respectively fixed on the outer sides of the first middle joint (602), the second middle joint (702), and the base (5). Rotation holes are provided on the outer sides of the first finger plate (2), the second finger plate (3), and the third finger plate (4). The cylinder (609) on the first front joint (601) is rotatably installed in the rotation hole on the first finger plate (2), the cylinder (609) on the second front joint (701) is rotatably installed in the rotation hole on the second finger plate (3), and the cylinder (609) on the third joint structure (8) is rotatably installed in the rotation hole on the third finger plate (4).

5. A coaxial equidistant line-driven joint according to claim 4, characterized in that: The first joint structure (6) further includes a first rear joint (603). Two ends of the first rear joint (603) are respectively fixed to a first middle joint (602) and a second front joint (701). Two first guiding wire holes (606) are formed inside the first rear joint (603). Two ends of the first guiding wire holes (606) are respectively located at two ends of the first rear joint (603). At one ends of the two first guiding wire holes (606), the two holes are respectively coaxially arranged with two first wire passing holes (604) on the first middle joint (602). At one ends of the two second guiding wire holes (705), the two holes are respectively coaxially arranged with two second wire passing holes (610) on the second front joint (701).

6. The coaxial equidistant line-driven joint according to claim 5, characterized in that: The second joint structure (7) further includes a second rear joint (703). Two third wire passing holes (704) are formed inside the second rear joint (703). Two second guiding wire holes (705) are formed inside the second rear joint (703). One ends of the two second guiding wire holes (705) are respectively communicated with the two third wire passing holes (704) and the other ends extend to the outside of the second rear joint (703). Two ends of the second rear joint (703) are respectively fixed to a second middle joint (702) and a third joint structure (8). Two fourth wire passing holes (706) are formed on the inner side wall of the second middle joint (702). The two third wire passing holes (704) are coaxially arranged with the two fourth wire passing holes (706) on the second middle joint (702), and the two third wire passing holes (704) are coaxially arranged with the two second wire passing holes (610) on the third joint structure (8). One ends of the two second guiding wire holes (705) are respectively coaxially arranged with the two first wire passing holes (604) on the second middle joint (702).

7. The coaxial equidistant line-driven joint according to claim 6, characterized in that: The wire driving mechanism includes a first driving wire (9). The middle end of the first driving wire (9) is fixed in an arc wire hole (607) of a first front joint (601). Two ends of the first driving wire (9) respectively pass through the two first wire passing holes (604) on the first middle joint (602), the two guiding wire holes on the first rear joint (603), the two second wire passing holes (610) on the second front joint (701), the fourth wire passing hole (706) on the second middle joint (702), the two third wire passing holes (704) on the second rear joint (703), and the two second wire passing holes (610) on the third joint structure (8) in sequence. First driving tubes (10) are sleeved on two ends of the first driving wire (9).

8. The coaxial equidistant line-driven joint according to claim 7, characterized in that: The wire driving mechanism further includes a second driving wire (13). The middle end of the second driving wire (13) is located in the arc-shaped wire hole (607) of the second front joint (701) and is fixed therein. The two ends of the second driving wire (13) respectively pass through the fourth wire passing hole (706) on the second middle joint (702), the two second guiding wire holes (705) on the second rear joint (703), and the two second wire passing holes (610) on the third joint structure (8). Second driving tubes (14) are sleeved on both ends of the second driving wire (13).

9. The coaxial equidistant line-driven joint according to claim 8, wherein: The wire driving mechanism further includes a third driving wire (11). The middle end of the third driving wire (11) is located in the arc-shaped wire hole (607) of the third joint structure (8) and is fixed therein. Third driving tubes (12) are sleeved on both ends of the third driving wire (11).

10. A coaxial equidistant line-driven joint according to any one of claims 3-9, characterized in that: A wire moving groove (605) is formed on one side of the first wire passing hole (604).

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