Three-degree-of-freedom rope-driven direct-driven serial wrist based on gear constraint

Abstract

The invention discloses a three-degree-of-freedom rope-driven direct-driven serial wrist based on gear constraint. The wrist comprises a first arm section, a second arm section, a third arm section, a clamping jaw, a first rope-driven mechanism, a second rope-driven mechanism and a third rope-driven mechanism. A gear joint rotating structure is arranged between the first end of the first arm section and the first end of the second arm section, a gear joint rotating structure is arranged between the second end of the second arm section and the first end of the third arm section, and the second end of the third arm section is rotationally connected with the clamping jaw. The rotating axial direction of the first end of the second arm section, the rotating axial direction of the first end of the third arm section and the rotating axial direction of the clamping jaw are perpendicular to one another in a pairwise mode. The first rope driving mechanism, the second rope driving mechanism and the third rope driving mechanism are respectively used for independently controlling the second arm section, the third arm section and the clamping jaw to rotate; the difficulty of parts and installation is greatly reduced, the difficulty of forward and inverse kinematics modeling is reduced, and the difficulty in the prior art is practically solved.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical arms, and in particular to a three-degree-of-freedom rope-driven direct-drive serial wrist based on gear constraints. Background Art

[0002] In recent years, a type of robot with rope-driven pure rolling joints has become a hot research and development hotspot in academia and industry. Compared with traditional industrial robot arms, the joint motors of this type of robot arms are placed near the base, and the power is transmitted to the joints through ropes, thereby reducing the arm mass and improving the agility of the robot arm. A significant feature of this type of robot arm that distinguishes it from traditional industrial robot arms is that it has rope-driven circular pure rolling joints or (and) rope-driven spherical pure rolling joints.

[0003] The relevant prior art is as follows:

[0004] Prior art 1, Y.-J.Kim, J.-I.Kim and W.Jang, "Quaternion Joint: Dexterous 3-DOF Joint Representing Quaternion Motion for High-Speed ​​Safe Interaction", 2018 IEEE / RSJ International Conference on Intelligent Robots and Systems (IROS), Madrid, Spain, 2018, pp.935-942. This article proposes a new type of dexterous three-degree-of-freedom (3-DOF) virtual spherical wrist mechanism for LIMS2, called a quaternion joint, which has a large range of motion and uniform manipulability without singularities throughout the entire range of motion. This joint consists of a 2-DOF spherical pure rolling joint and two pairs of drive ropes, which can be regarded as a parallel joint. Based on this feature, it has simple and clear forward and inverse kinematics and high manipulability. By adding a 1-DOF rotation joint at the distal end of the quaternion joint, it can be expanded to a 3-DOF joint mechanism.

[0005] The design of the quaternion virtual spherical wrist joint has many significant advantages, such as large range of motion, high maneuverability, light weight, simple and reliable structure, etc. However, the joint also has some disadvantages, as shown below:

[0006] 1. The design of the quaternion virtual spherical wrist joint is complex, with many parts, making it difficult to install, and the complexity brought by the rope installation is also very large.

[0007] 2. The positive kinematics of the quaternion virtual spherical wrist joint is relatively complex and not as simple and clear as the traditional serial joint.

[0008] 3. The quaternion virtual spherical wrist joint has low stiffness, which may lead to large accuracy differences when facing high loads.

[0009] 4. The above joints are purely mechanical joints without feedback mechanisms, and their accuracy depends entirely on the degree of rope stretching and the friction between the rope pulleys.

[0010] Existing technology 2: The UR5 robot arm is a lightweight collaborative industrial robot arm developed by Universal Robots of Denmark. It is known for its ease of use, flexibility and safety. The design of the UR5 robot arm focuses on user experience. Its setup and deployment process is fast and flexible, allowing it to be easily integrated into existing production lines to help improve production efficiency and quality. In addition, the UR5e is an upgraded version of the UR5, providing more features and improved performance, including higher repeatability and wider application adaptability.

[0011] The wrist joint of the robot has 3 degrees of freedom, and the 3 degrees of freedom are offset, which can be regarded as a series connection of three joints. The advantage of this design is that the forward and inverse kinematics of the wrist joint is relatively simple, and the DH method can be used directly for modeling. In addition, the concept of modular design is adopted, which is easy to repair and replace. However, the UR5 wrist joint still has the following disadvantages:

[0012] 1. The mass is large. Since the motor is directly installed on the rotary joint, the mass of the wrist joint is relatively large, which makes the ratio of its own weight to load larger. The overall weight of the UR5 robot arm is 18.4kg, and its maximum load is only 5kg.

[0013] 2. Due to the large mass of the wrist, the running speed of the wrist joint is low, and it may be difficult to face some special scenarios.

[0014] 3. The wrist has relatively large rigidity, resulting in poor safety during operation.

[0015] Therefore, how to solve the above-mentioned problems of the prior art has become a difficult problem to be solved urgently by those skilled in the art. Summary of the invention

[0016] The object of the present invention is to provide a three-degree-of-freedom cable-driven direct-drive tandem wrist based on gear constraints to solve the problems of complex structure and difficult design of the existing ones.

[0017] In order to solve the above technical problems, the present invention provides a three-degree-of-freedom rope-driven direct-drive tandem wrist based on gear constraints, comprising a first arm segment, a second arm segment, a third arm segment, a clamp, a first rope-driven mechanism, a second rope-driven mechanism and a third rope-driven mechanism; a gear joint rotation structure is provided between the first end of the first arm segment and the second arm segment, a gear joint rotation structure is provided between the second end of the second arm segment and the first end of the third arm segment, the second end of the third arm segment is rotationally connected to the clamp, and the rotation axis of the first end of the second arm segment, the rotation axis of the first end of the third arm segment, and the rotation axis of the clamp are perpendicular to each other; the first rope-driven mechanism, the second rope-driven mechanism and the third rope-driven mechanism are respectively used to independently control the rotation of the second arm segment, the third arm segment and the clamp.

[0018] In one embodiment, the first arm segment is provided with two first gear plates that are separated and oppositely arranged, and the first end of the second arm segment is provided with two second front gear plates that are separated and oppositely arranged, and the two first gear plates are respectively meshed with the two second front gear plates; the three-degree-of-freedom rope-driven direct-drive tandem wrist also includes a first connecting plate, and the two first connecting plates are respectively arranged on both sides of the first arm segment and the second arm segment, and the first rotating shaft and the second front rotating shaft are respectively rotatably connected between the two sides of the two first connecting plates, the first rotating shaft passes through the two first gear plates to form a fixed connection, and the second front rotating shaft passes through the two second front gear plates to form a fixed connection.

[0019] In one embodiment, the first rope drive mechanism includes a first force winding wheel and a first driving rope, the two first force winding wheels are connected and fixed on the second front rotating shaft, the two first driving ropes are respectively wound around the two first force winding wheels in opposite winding directions, and the two first driving ropes are respectively connected and fixed to the two first force winding wheels, and the pulling of the two first driving ropes is used to drive the second arm segment to rotate in different directions.

[0020] In one embodiment, the first arm section is provided with a positioning shaft, and the axial direction of the positioning shaft is the same as the axial direction of the first rotating shaft; the first rope drive mechanism also includes a No. 11 rope winding wheel and a No. 12 rope winding wheel, the two No. 11 rope winding wheels are arranged on the positioning shaft, and the two No. 12 rope winding wheels are arranged on the first rotating shaft, and the first driving rope is wound around the No. 11 rope winding wheel, the No. 12 rope winding wheel and the first force winding wheel in an alternating winding direction.

[0021] In one embodiment, the second end of the second arm segment is provided with two second rear gear plates that are separated and oppositely arranged, and the first end of the third arm segment is provided with two third gear plates that are separated and oppositely arranged, and the two second rear gear plates are respectively engaged with the two third gear plates; the three-degree-of-freedom rope-driven direct-drive tandem wrist also includes a second connecting plate, and the two sides of the second connecting plate are respectively arranged between the two second rear gear plates and between the two third gear plates, and the two sides of the second connecting plate are respectively provided with a second rear rotating shaft and a third rotating shaft, the second rear rotating shaft passes through the two second rear gear plates to form a fixed connection, and the third rotating shaft passes through the two third gear plates to form a rotating connection.

[0022] In one embodiment, the second rope drive mechanism includes a second force winding wheel and a second driving rope, the two second force winding wheels are respectively connected and fixed to the outside of the two third gear plates, the two second force winding wheels are respectively sleeved on the outside of the two ends of the third rotating shaft to form a rotational connection, the two second driving ropes are respectively wound around the two second force winding wheels in opposite winding directions, and the two second driving ropes are respectively connected and fixed to the two second force winding wheels, and the pulling of the two second driving ropes is used to drive the third arm segment to rotate in different directions.

[0023] In one embodiment, the second rope drive mechanism also includes a No. 21 rope winding wheel, a No. 22 rope winding wheel, a No. 23 rope winding wheel, a No. 24 rope winding wheel and a No. 25 rope winding wheel; the two No. 21 rope winding wheels are arranged on the first rotating shaft; the two No. 22 rope winding wheels are arranged on the second front rotating shaft; the two No. 23 rope winding wheels, and the two No. 24 rope winding wheels are respectively arranged on the two opposite surfaces of the second arm segment, and the central axes of the two No. 23 rope winding wheels and the central axes of the two No. 24 rope winding wheels are consistent with the central axis of the third rotating shaft; the two No. 25 rope winding wheels are respectively arranged at both ends of the second rear rotating shaft; the second driving rope is wound around the No. 21 rope winding wheel, the No. 22 rope winding wheel, the No. 23 rope winding wheel, the No. 24 rope winding wheel, the No. 25 rope winding wheel and the second force winding wheel in an alternating winding direction.

[0024] In one of the embodiments, the third rope drive mechanism includes a first bevel gear, a second bevel gear, a third force winding wheel, a third driving rope and a transmission module; the first bevel gear is arranged on the third arm segment, the second bevel gear is connected and fixed to the clamping jaw, and the first bevel gear and the second bevel gear are arranged perpendicular to each other and meshed; the two third force winding wheels are fixedly connected to the two ends of the third rotating shaft, the two first driving ropes are respectively wound around the two third force winding wheels in opposite winding directions, and the two third driving ropes are respectively connected and fixed to the two third force winding wheels; one of the third force winding wheels is connected to the first bevel gear through the transmission module, so that the pulling of the two third driving ropes is used to drive the clamping jaw to rotate in different directions.

[0025] In one embodiment, the third rope drive mechanism also includes a rope winding wheel No. 31, a rope winding wheel No. 32, a rope winding wheel No. 33, a rope winding wheel No. 34 and a rope winding wheel No. 35; two of the rope winding wheels No. 31 are arranged on the first rotating shaft; two of the rope winding wheels No. 32 are arranged on the second front rotating shaft; two of the rope winding wheels No. 33 and two of the rope winding wheels No. 34 are respectively arranged on two opposite surfaces of the second arm segment, and the central axes of the two rope winding wheels No. 33 and the central axes of the two rope winding wheels No. 34 are consistent with the central axis of the third rotating shaft; the two rope winding wheels No. 35 are respectively arranged on the two ends of the second rear rotating shaft; the third driving rope is wound around the No. 31 rope winding wheel, the No. 32 rope winding wheel, the No. 33 rope winding wheel, the No. 34 rope winding wheel, the No. 35 rope winding wheel and the third force rope winding wheel in an alternating winding direction; the transmission module includes a first transmission rope winding wheel, a second transmission rope winding wheel and a transmission rope; the first transmission rope winding wheel is coaxially connected and fixed to one of the third force rope winding wheels; the second transmission rope winding wheel is coaxially connected and fixed to the first bevel gear; the transmission rope is wound around the first transmission rope winding wheel and the second transmission rope winding wheel in an 8-shape.

[0026] In one embodiment, encoders are provided at the rotational connection between the first arm segment and the second arm segment, the rotational connection between the second arm segment and the third arm segment, and the rotational connection between the clamp and the third arm segment.

[0027] The beneficial effects of the present invention are as follows:

[0028] 1. The three-degree-of-freedom cable-driven direct-drive tandem wrist designed by the present invention has greatly reduced parts and installation difficulty.

[0029] 2. The three-degree-of-freedom cable-driven direct-drive serial wrist designed in the present invention can effectively reduce the difficulty of forward and inverse kinematics modeling.

[0030] 3. The swivel joint designed in the present invention has gear meshing, which improves the precision and the rigidity of the wrist structure.

[0031] 4. Integrated encoder improves joint accuracy while ensuring compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a schematic diagram of the structure provided by an embodiment of the present invention;

[0034] Figure 2 yes Figure 1 Schematic diagram of the structure after some parts are removed;

[0035] Figure 3 yes Figure 1 A schematic diagram of the transmission structure of the first rope drive mechanism;

[0036] Figure 4 yes Figure 1 A schematic diagram of the transmission structure of the second rope drive mechanism;

[0037] Figure 5 yes Figure 4 Schematic diagram of the winding method of the first and second drive ropes;

[0038] Figure 6 yes Figure 4 Schematic diagram of the winding method of the second second driving rope;

[0039] Figure 7 yes Figure 1 Schematic diagram of the transmission structure of the third rope drive mechanism;

[0040] Figure 8 yes Figure 7 Schematic diagram of the winding method of the first third drive rope;

[0041] Fig. 9 yes Figure 7 Schematic diagram of the winding method of the second and third drive ropes;

[0042] Fig.10 yes Figure 1 Schematic diagram of the encoder setting position.

[0043] The reference numerals are as follows:

[0044] 10. first arm section; 11. first gear plate; 12. positioning shaft;

[0045] 20. second arm section; 21. second front gear plate; 22. second rear gear plate;

[0046] 30. third arm section; 31. third gear plate;

[0047] 40. Gripping jaws;

[0048] 50. First rope drive mechanism; 51. First force-bearing rope winding wheel; 52. First driving rope; 531. No. 11 rope winding wheel; 532. No. 12 rope winding wheel;

[0049] 60. Second rope drive mechanism; 61. Second force-bearing rope winding wheel; 62. Second driving rope; 631. Rope winding wheel No. 21; 632. Rope winding wheel No. 22; 633. Rope winding wheel No. 23; 634. Rope winding wheel No. 24; 635. Rope winding wheel No. 25;

[0050] 70. The third rope drive mechanism; 71. The third force winding wheel; 72. The third driving rope; 731. The winding wheel No. 31; 732. The winding wheel No. 32; 733. The winding wheel No. 33; 734. The winding wheel No. 34; 735. The winding wheel No. 35; 741. The first bevel gear; 742. The second bevel gear; 75. The transmission module; 751. The first transmission winding wheel; 752. The second transmission winding wheel; 753. The transmission rope;

[0051] 811, first connecting plate; 812, second connecting plate; 82, encoder;

[0052] 91, first rotating shaft; 921, second front rotating shaft; 922, second rear rotating shaft; 93, third rotating shaft. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0054] The present invention provides a three-degree-of-freedom cable-driven direct-drive tandem wrist based on gear constraints, and its implementation example Figure 1As shown, it includes a first arm segment 10, a second arm segment 20, a third arm segment 30, a clamp 40, a first rope drive mechanism 50, a second rope drive mechanism 60 and a third rope drive mechanism 70; a gear joint rotation structure is provided between the first end of the first arm segment 10 and the second arm segment 20, a gear joint rotation structure is provided between the second end of the second arm segment 20 and the first end of the third arm segment 30, the second end of the third arm segment 30 is rotationally connected to the clamp 40, and the rotation axis of the first end of the second arm segment 20, the rotation axis of the first end of the third arm segment 30, and the rotation axis of the clamp 40 are perpendicular to each other; the first rope drive mechanism 50, the second rope drive mechanism 60 and the third rope drive mechanism 70 are respectively used to independently control the rotation of the second arm segment 20, the third arm segment 30 and the clamp 40.

[0055] After adopting this setting method, since there is a gear joint rotation structure between the first arm segment 10 and the first end of the second arm segment 20, and there is a gear joint rotation structure between the second end of the second arm segment 20 and the first end of the third arm segment 30, this structure not only improves the rotation control accuracy, but also improves the rigidity of the wrist structure; and the first rope drive mechanism 50, the second rope drive mechanism 60, and the third rope drive mechanism 70 are respectively used to independently control the rotation of the second arm segment 20, the third arm segment 30 and the clamp 40, which also greatly reduces the parts and installation difficulty.

[0056] like Figure 1 and Figure 2 As shown, in this embodiment, the first arm segment 10 is provided with two separated and oppositely arranged first gear plates 11, and the first end of the second arm segment 20 is provided with two separated and oppositely arranged second front gear plates 21, and the two first gear plates 11 are respectively meshed with the two second front gear plates 21; the three-degree-of-freedom rope-driven direct-drive tandem wrist also includes a first connecting plate 811, and the two first connecting plates 811 are respectively arranged on both sides of the first arm segment 10 and the second arm segment 20, and the two sides of the two first connecting plates 811 are respectively rotatably connected with a first rotating shaft 91 and a second front rotating shaft 921, the first rotating shaft 91 passes through the two first gear plates 11 to form a fixed connection, and the second front rotating shaft 921 passes through the two second front gear plates 21 to form a fixed connection; so after adopting this setting method, the formation of a gear joint rotation structure between the first arm segment 10 and the second arm segment 20 can be realized.

[0057] like Figures 1 to 3 As shown, this embodiment provides a first rope drive mechanism 50 including a first force winding wheel 51 and a first driving rope 52. The two first force winding wheels 51 are connected and fixed on the second front rotating shaft 921. The two first driving ropes 52 are respectively wound around the two first force winding wheels 51 in opposite winding directions, and the two first driving ropes 52 are respectively connected and fixed to the two first force winding wheels 51. The pulling of the two first driving ropes 52 is used to drive the second arm segment 20 to rotate in different directions.

[0058] After adopting this setting method, if pulling the first first drive rope 52 can control one of the first force-bearing rope wheels 51 to rotate clockwise, then the second arm segment 20 can be driven to rotate clockwise; similarly, if pulling the second first drive rope 52 can control the other first force-bearing rope wheel 51 to rotate counterclockwise, then the second arm segment 20 can be driven to rotate counterclockwise, thereby achieving the purpose of bidirectional rotation control switching of the second arm segment 20.

[0059] like Figures 1 to 3 As shown, in this embodiment, the first arm section 10 is provided with a positioning shaft 12, and the axial direction of the positioning shaft 12 is the same as the axial direction of the first rotating shaft 91; the first rope drive mechanism 50 also includes a No. 11 rope winding wheel 531 and a No. 12 rope winding wheel 532, the two No. 11 rope winding wheels 531 are arranged on the positioning shaft 12, and the two No. 12 rope winding wheels 532 are arranged on the first rotating shaft 91, and the first driving rope 52 is wound around the No. 11 rope winding wheel 531, the No. 12 rope winding wheel 532 and the first force rope winding wheel 51 in an alternating winding direction.

[0060] like Figure 1 and Figure 3 As shown, at this time, the first driving rope 52 near the top passes over the top of the No. 1 rope winding wheel 531 near the top, then passes over the bottom of the No. 1 and No. 2 rope winding wheels 532, and finally passes over the top of the first force rope winding wheel 51, and is connected and fixed to the first force rope winding wheel 51, so once the first driving rope 52 is pulled to the left, the first force rope winding wheel 51 and the second arm segment 20 will rotate counterclockwise synchronously.

[0061] Similar, such as Figure 1 and Figure 3 As shown, at this time, the first driving rope 52 near the bottom passes through the bottom of the No. 1 rope winding wheel 531 near the bottom, then passes through the top of the No. 1 and No. 2 rope winding wheels 532, and finally passes through the bottom of the first force rope winding wheel 51, and is connected and fixed to the first force rope winding wheel 51, so once the first driving rope 52 is pulled to the left, the first force rope winding wheel 51 and the second arm segment 20 will rotate clockwise synchronously.

[0062] like Figure 1 and Figure 2As shown, in this embodiment, the second end of the second arm segment 20 is provided with two separated and oppositely arranged second rear gear plates 22, and the first end of the third arm segment 30 is provided with two separated and oppositely arranged third gear plates 31, and the two second rear gear plates 22 are respectively meshed with the two third gear plates 31; the three-degree-of-freedom rope-driven direct-drive tandem wrist also includes a second connecting plate 812, and the two sides of the second connecting plate 812 are respectively arranged between the two second rear gear plates 22 and between the two third gear plates 31, and the two sides of the second connecting plate 812 are respectively provided with a second rear rotating shaft 922 and a third rotating shaft 93, the second rear rotating shaft 922 passes through the two second rear gear plates 22 to form a fixed connection, and the third rotating shaft 93 passes through the two third gear plates 31 to form a rotating connection; so after adopting this setting method, the formation of the gear joint rotation structure between the second arm segment 20 and the third arm segment 30 can be realized.

[0063] like Figure 1 , Figure 2 ,as well as Figures 4 to 6 As shown, this embodiment provides a second rope drive mechanism 60 including a second force winding wheel 61 and a second driving rope 62. The two second force winding wheels 61 are respectively connected and fixed to the outside of the two third gear plates 31. The two second force winding wheels 61 are respectively sleeved on the two ends of the third rotating shaft 93 to form a rotational connection. The two second driving ropes 62 are respectively wound around the two second force winding wheels 61 in opposite winding directions, and the two second driving ropes 62 are respectively connected and fixed to the two second force winding wheels 61. The pulling of the two second driving ropes 62 is used to drive the third arm segment 30 to rotate in different directions.

[0064] After adopting this setting, if pulling the first second drive rope 62 can control one of the second force-bearing rope pulleys 61 to rotate clockwise, the third arm segment 30 can be driven to rotate clockwise; similarly, if pulling the second second drive rope 62 can control the other second force-bearing rope pulley 61 to rotate counterclockwise, the third arm segment 30 can be driven to rotate counterclockwise, thereby achieving the purpose of bidirectional rotation control switching of the third arm segment 30.

[0065] like Figure 1 , Figure 2 ,as well as Figures 4 to 6As shown, the second rope drive mechanism 60 of this embodiment further includes a No. 21 rope reel 631, a No. 22 rope reel 632, a No. 23 rope reel 633, a No. 24 rope reel 634 and a No. 25 rope reel 635; the two No. 21 rope reels 631 are arranged on the first rotating shaft 91; the two No. 22 rope reels 632 are arranged on the second front rotating shaft 921; the two No. 23 rope reels 633, and the two No. 24 rope reels 634 are respectively arranged on the two opposite surfaces of the second arm section 20 The central axes of the two No. 23 rope wheels 633 and the two No. 24 rope wheels 634 are all consistent with the central axis of the third rotating shaft 93; the two No. 25 rope wheels 635 are respectively arranged at both ends of the second rear rotating shaft 922; the second driving rope 62 is wound around the No. 21 rope wheel 631, the No. 22 rope wheel 632, the No. 23 rope wheel 633, the No. 24 rope wheel 634, the No. 25 rope wheel 635 and the second force rope wheel 61 in an alternating winding direction.

[0066] like Figure 1 and Figure 5 As shown, at this time, the second drive rope 62 is passed through the top of the No. 21 rope pulley 631, the bottom of the No. 22 rope pulley 632, the rear of the No. 23 rope pulley 633, the front of the No. 24 rope pulley 634, the rear of the No. 25 rope pulley 635, and the front of the second force rope pulley 61 in sequence, and is connected and fixed to the second force rope pulley 61, so once the second drive rope 62 is pulled to the left, the second force rope pulley 61 and the third arm segment 30 will rotate clockwise synchronously.

[0067] Similar, such as Figure 1 and Figure 6 As shown, at this time, another second driving rope 62 is passed through from the bottom of another No. 21 rope pulley 631, above the No. 22 rope pulley 632, in front of the No. 23 rope pulley 633, behind the No. 24 rope pulley 634, in front of the No. 25 rope pulley 635, and behind the second force rope pulley 61 in sequence, and is connected and fixed to the second force rope pulley 61, so once the second driving rope 62 is pulled to the left, the second force rope pulley 61 and the third arm segment 30 will rotate counterclockwise synchronously.

[0068] like Figure 1 , Figure 2 ,as well as Figures 7 to 9As shown, this embodiment provides a third rope drive mechanism 70 including a first bevel gear 741, a second bevel gear 742, a third force winding wheel 71, a third drive rope 72 and a transmission module 75; the first bevel gear 741 is arranged on the third arm section 30, the second bevel gear 742 is connected and fixed to the clamping jaw 40, and the first bevel gear 741 and the second bevel gear 742 are arranged perpendicular to each other and meshed; the two third force winding wheels 71 are fixedly connected to the two ends of the third rotating shaft 93, the two first drive ropes 52 are respectively wound around the two third force winding wheels 71 in opposite winding directions, and the two third drive ropes 72 are respectively connected and fixed to the two third force winding wheels 71; one of the third force winding wheels 71 is transmission-connected to the first bevel gear 741 through the transmission module 75, so that the pulling of the two third drive ropes 72 is used to drive the clamping jaw 40 to rotate in different directions.

[0069] After adopting this setting, if pulling the first third drive rope 72 can control one of the third force-bearing rope pulleys 71 to rotate clockwise, the first bevel gear 741, the second bevel gear 742 and the clamp 40 can be controlled to rotate in one direction through the transmission module 75; similarly, if pulling the second third drive rope 72 can control the other third force-bearing rope pulley 71 to rotate counterclockwise, the first bevel gear 741, the second bevel gear 742 and the clamp 40 can be controlled to rotate in the other direction through the transmission module 75, thereby achieving the purpose of bidirectional rotation control switching of the clamp 40.

[0070] like Figure 1 , Figure 2 ,as well as Figures 7 to 9As shown, the third rope drive mechanism 70 of this embodiment also includes a No. 31 rope winding wheel 731, a No. 32 rope winding wheel 732, a No. 33 rope winding wheel 733, a No. 34 rope winding wheel 734 and a No. 35 rope winding wheel 735; the two No. 31 rope winding wheels 731 are arranged on the first rotating shaft 91; the two No. 32 rope winding wheels 732 are arranged on the second front rotating shaft 921; the two No. 33 rope winding wheels 733, and the two No. 34 rope winding wheels 734 are respectively arranged on the two opposite surfaces of the second arm section 20, and the central axis of the two No. 33 rope winding wheels 733 and the central axis of the two No. 34 rope winding wheels 734 are both consistent with the central axis of the third rotating shaft 93; the two No. 35 rope winding wheels 735 are respectively arranged on the second front rotating shaft 921. Two ends of the rear rotating shaft 922; the third driving rope 72 is wound around the No. 31 rope wheel 731, the No. 32 rope wheel 732, the No. 33 rope wheel 733, the No. 34 rope wheel 734, the No. 35 rope wheel 735 and the third force rope wheel 71 in an alternating winding direction; the transmission module 75 includes a first transmission rope wheel 751, a second transmission rope wheel 752 and a transmission rope 753; the first transmission rope wheel 751 is coaxially connected and fixed to one of the third force rope wheels 71; the second transmission rope wheel 752 is coaxially connected and fixed to the first bevel gear 741; the transmission rope 753 is wound around the first transmission rope wheel 751 and the second transmission rope wheel 752 in an 8-shape.

[0071] like Figures 7 to 9 As shown, at this time, the third driving rope 72 is passed around from above the No. 31 rope winding wheel 731, below the No. 32 rope winding wheel 732, behind the No. 33 rope winding wheel 733, in front of the No. 34 rope winding wheel 734, on the left side of the No. 35 rope winding wheel 735, and on the right side of the third force rope winding wheel 71 in sequence, and is connected and fixed to the third force rope winding wheel 71, so once the third driving rope 72 is pulled to the left, the third force rope winding wheel 71 will rotate clockwise; and because the third rotating shaft 93, the two third force rope winding wheels 71, and the first transmission rope winding wheel 751 are a synchronous rotation structure, the first transmission rope winding wheel 751 will also rotate clockwise at this time, thereby driving the subsequent transmission rope 753, the second transmission rope winding wheel 752, the first bevel gear 741, the second bevel gear 742 and the clamp 40 to rotate.

[0072] Similarly, at this time, another third driving rope 72 is passed around from the bottom of the No. 31 rope winding wheel 731, the top of the No. 32 rope winding wheel 732, the front of the No. 33 rope winding wheel 733, the rear of the No. 34 rope winding wheel 734, the left side of the No. 35 rope winding wheel 735, and the right side of the third force rope winding wheel 71 in sequence, and is connected and fixed to the third force rope winding wheel 71, so once the third driving rope 72 is pulled to the left, the third force rope winding wheel 71 will rotate counterclockwise; and because the third rotating shaft 93, the two third force rope winding wheels 71, and the first transmission rope winding wheel 751 are a synchronous rotation structure, the first transmission rope winding wheel 751 will also rotate counterclockwise at this time, thereby driving the subsequent transmission rope 753, the second transmission rope winding wheel 752, the first bevel gear 741, the second bevel gear 742 and the clamp 40 to rotate in another direction.

[0073] like Fig.10 As shown, in this embodiment, encoders 82 are provided at the rotational connection between the first arm segment 10 and the second arm segment 20 , the rotational connection between the second arm segment 20 and the third arm segment 30 , and the rotational connection between the clamp 40 and the third arm segment 30 .

[0074] Since the rope will stretch when subjected to axial force, and the rope in reality is not an ideal rope, the axial force of the rope at different positions may be different, which will cause the rope to change in length when driving the joint to rotate, resulting in motion output deviation. Therefore, this embodiment integrates an encoder 82 at the above-mentioned rotating connection.

[0075] Specifically, two encoders 82 are provided at the place where the first arm segment 10 and the second arm segment 20 rotate. They are AS5047P magnetic encoders with an accuracy of 0.022°. Since there are gear constraints between the joints, the two AS5047P magnetic encoders are distributed on both sides, which can eliminate the mechanical errors caused by gear processing to the greatest extent, and the two magnetic encoders sample timing.

[0076] The remaining encoder 82 uses King Kong Technology's 16-bit hollow magnetic encoder with an accuracy of up to 0.0055°.

[0077] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A three-degree-of-freedom cable-driven direct-drive tandem wrist based on gear constraints, characterized in that: It includes a first arm segment, a second arm segment, a third arm segment, a clamping claw, a first rope driving mechanism, a second rope driving mechanism and a third rope driving mechanism; A gear joint rotation structure is provided between the first arm segment and the first end of the second arm segment, a gear joint rotation structure is provided between the second end of the second arm segment and the first end of the third arm segment, the second end of the third arm segment is rotationally connected to the clamp, and the rotation axis of the first end of the second arm segment, the rotation axis of the first end of the third arm segment, and the rotation axis of the clamp are perpendicular to each other; The first rope drive mechanism, the second rope drive mechanism, and the third rope drive mechanism are respectively used to independently control the rotation of the second arm segment, the third arm segment, and the clamping claw.

2. The three-degree-of-freedom cable-driven direct-drive tandem wrist according to claim 1, characterized in that: The first arm section is provided with two first gear plates which are separated and oppositely arranged, and the first end of the second arm section is provided with two second front gear plates which are separated and oppositely arranged, and the two first gear plates are respectively meshed with the two second front gear plates; The three-degree-of-freedom rope-driven direct-drive tandem wrist also includes a first connecting plate, and the two first connecting plates are respectively arranged on both sides of the first arm segment and the second arm segment, and the first rotating shaft and the second front rotating shaft are respectively rotatably connected between the two sides of the two first connecting plates, and the first rotating shaft passes through the two first gear plates to form a fixed connection, and the second front rotating shaft passes through the two second front gear plates to form a fixed connection.

3. The three-degree-of-freedom cable-driven direct-drive tandem wrist according to claim 2, characterized in that: The first rope drive mechanism includes a first force winding wheel and a first driving rope. The two first force winding wheels are connected and fixed on the second front rotating shaft. The two first driving ropes are respectively wound around the two first force winding wheels in opposite winding directions, and the two first driving ropes are respectively connected and fixed to the two first force winding wheels. The pulling of the two first driving ropes is used to drive the second arm segment to rotate in different directions.

4. The three-degree-of-freedom cable-driven direct-drive tandem wrist according to claim 3, characterized in that: The first arm section is provided with a positioning shaft, and the axial direction of the positioning shaft is the same as the axial direction of the first rotating shaft; The first rope drive mechanism also includes a No. 11 rope winding wheel and a No. 12 rope winding wheel. The two No. 11 rope winding wheels are arranged on the positioning shaft, and the two No. 12 rope winding wheels are arranged on the first rotating shaft. The first driving rope is wound around the No. 11 rope winding wheel, the No. 12 rope winding wheel and the first force rope winding wheel in an alternating winding direction.

5. The three-degree-of-freedom cable-driven direct-drive tandem wrist according to claim 1, characterized in that: The second end of the second arm section is provided with two second rear gear plates which are separated and oppositely arranged, and the first end of the third arm section is provided with two third gear plates which are separated and oppositely arranged, and the two second rear gear plates are respectively meshed with the two third gear plates; The three-degree-of-freedom rope-driven direct-drive tandem wrist also includes a second connecting plate, the two sides of the second connecting plate are respectively arranged between the two second rear gear plates and between the two third gear plates, the two sides of the second connecting plate are respectively provided with a second rear rotating shaft and a third rotating shaft, the second rear rotating shaft passes through the two second rear gear plates to form a fixed connection, and the third rotating shaft passes through the two third gear plates to form a rotating connection.

6. The three-degree-of-freedom cable-driven direct-drive tandem wrist according to claim 5, characterized in that: The second rope drive mechanism includes a second force winding wheel and a second driving rope, the two second force winding wheels are respectively connected and fixed to the outside of the two third gear plates, the two second force winding wheels are respectively sleeved on the outside of the two ends of the third rotating shaft to form a rotational connection, the two second driving ropes are respectively wound around the two second force winding wheels in opposite winding directions, and the two second driving ropes are respectively connected and fixed to the two second force winding wheels, and the pulling of the two second driving ropes is used to drive the third arm segment to rotate in different directions.

7. The three-degree-of-freedom cable-driven direct-drive tandem wrist according to claim 6, characterized in that: The second rope drive mechanism also includes a rope winding wheel No. 21, a rope winding wheel No. 22, a rope winding wheel No. 23, a rope winding wheel No. 24 and a rope winding wheel No. 25; The two rope winding wheels No. 2 and No. 1 are arranged on the first rotating shaft; The two No. 2 rope winding wheels are arranged on the second front rotating shaft; The two No. 2 and No. 3 rope winding wheels, and the two No. 2 and No. 4 rope winding wheels are respectively arranged on two opposite surfaces of the second arm section, and the central axis of the two No. 2 and No. 3 rope winding wheels, and the central axis of the two No. 2 and No. 4 rope winding wheels are consistent with the central axis of the third rotating shaft; The two No. 2 and No. 5 rope winding wheels are respectively arranged at two ends of the second rear rotating shaft; The second driving rope is wound around the No. 21 rope winding wheel, the No. 22 rope winding wheel, the No. 23 rope winding wheel, the No. 24 rope winding wheel, the No. 25 rope winding wheel and the second force rope winding wheel in an alternating winding direction.

8. The three-degree-of-freedom cable-driven direct-drive tandem wrist according to claim 1, characterized in that: The third rope drive mechanism comprises a first bevel gear, a second bevel gear, a third force-bearing rope winding wheel, a third driving rope and a transmission module; The first bevel gear is arranged on the third arm segment, the second bevel gear is connected and fixed to the clamping claw, and the first bevel gear and the second bevel gear are arranged perpendicular to each other and meshed; The two third force-bearing rope winding wheels are fixedly connected to the two ends of the third rotating shaft, the two first driving ropes are respectively wound around the two third force-bearing rope winding wheels in opposite winding directions, and the two third driving ropes are respectively connected and fixed to the two third force-bearing rope winding wheels; One of the third force-bearing rope wheels is connected to the first bevel gear through the transmission module, so that the pulling of the two third drive ropes is used to drive the clamping claws to rotate in different directions.

9. The three-degree-of-freedom cable-driven direct-drive tandem wrist according to claim 8, characterized in that: The third rope drive mechanism also includes a rope winding wheel No. 31, a rope winding wheel No. 32, a rope winding wheel No. 33, a rope winding wheel No. 34 and a rope winding wheel No. 35; The two No. 31 rope winding wheels are arranged on the first rotating shaft; The two said No. 3 and No. 2 rope winding wheels are arranged on the second front rotating shaft; The two No. 33 rope winding wheels and the two No. 34 rope winding wheels are respectively arranged on two opposite surfaces of the second arm section, and the central axial directions of the two No. 33 rope winding wheels and the two No. 34 rope winding wheels are consistent with the central axial direction of the third rotating shaft; The two No. 3 and No. 5 rope winding wheels are respectively arranged at two ends of the second rear rotating shaft; The third driving rope is wound around the No. 31 rope winding wheel, the No. 32 rope winding wheel, the No. 33 rope winding wheel, the No. 34 rope winding wheel, the No. 35 rope winding wheel and the third force rope winding wheel in an alternating winding direction; The transmission module comprises a first transmission rope wheel, a second transmission rope wheel and a transmission rope; The first transmission rope winding wheel is coaxially connected and fixed to one of the third force rope winding wheels; The second transmission rope winding wheel is coaxially connected and fixed to the first bevel gear; The transmission rope is wound around the first transmission rope wheel and the second transmission rope wheel in an 8-shape.

10. The three-degree-of-freedom cable-driven direct-drive tandem wrist according to claim 1, characterized in that: Encoders are provided at the rotational connection between the first arm segment and the second arm segment, at the rotational connection between the second arm segment and the third arm segment, and at the rotational connection between the clamp and the third arm segment.

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