Under-actuated robot finger with rigid-flexible hybrid transmission mechanism

Abstract

The invention discloses an under-actuated robot finger with a rigid-flexible hybrid transmission mechanism, and relates to the technical field of intelligent robots. The connecting seat is fixed at the top end of the gear box, a rotating shaft is mounted in the middle of the connecting seat, a worm gear is sleeved on the rotating shaft, and the rotating shaft is meshed with the worm; the tail end of the knuckle shell is rotatably connected with the worm gear; the tail end of the swinging arm is hinged to the front side edge of the connecting seat; a limiting groove is formed in the top end of the swinging arm; the tail end of the driving arm is hinged to the rear side edge of the surface of the worm gear, the top end of the driving arm is hinged to the inner side end of the sliding rod, the fingertip assembly comprises a flexible base and a rigid framework and is provided with a spring hinged to the top end of the knuckle shell, and the outer side end of the sliding rod is hinged to a rigid supporting rod embedded into the fingertip assembly. The rigid-flexible hybrid transmission mechanism is combined with the under-actuated design, the method is simple and easy to implement, the requirements of the humanoid prosthetic finger on the aspects of size, weight, integration and grabbing envelope are met, the characteristic of coupling-adaptive movement is achieved, and the flexibility and comfort are improved.

Description

Technical Field

[0001] The invention relates to the technical field of intelligent robots, in particular to an underactuated robot finger with a rigid-flexible hybrid transmission mechanism. Background Art

[0002] With the continuous advancement of robotics technology, more and more research and development work is focused on how to better imitate the movements and functions of human hands. As the core component of the prosthetic system, robotic fingers undertake extremely important tasks. In order to improve the functionality of robotic fingers, current research mainly focuses on humanoid design, humanoid size, low cost and lightweight. However, existing robotic fingers generally have the following significant problems:

[0003] Insufficient humanoid design: Currently, many robot fingers still use traditional electrical drive systems and are operated by separate mechanical devices in each part. Although these designs can achieve basic finger movements, since the movement of human fingers is a highly coordinated and complex process, existing designs often fail to meet the requirements in terms of delicate grasping, pinching, and precise operation. Especially in the control of grasping, the existing technology has obvious limitations and cannot effectively simulate the natural coordinated movement of human hands.

[0004] Limitations of humanoid size: In order to improve the flexibility and adaptability of prosthetic hands, the size and proportion of fingers must be as close to that of human hands as possible. However, existing prosthetic fingers usually use traditional drive methods, which leads to complex finger structures and a large difference in size and proportion with human hands, which makes prosthetic fingers lack comfort and naturalness during use. Existing prosthetic fingers often have a large gap with human fingers in length, joint spacing and knuckle motion range, which affects the wearer's operating experience and comfort.

[0005] High cost and heavy weight: Current prosthetic finger designs usually require more complex drive mechanisms and high-precision control systems, resulting in a high overall cost of the device, especially when using high-precision motors and transmission systems, which further increases manufacturing and maintenance costs. In addition, since traditional drive methods require larger motors and mechanical components, the overall weight is heavy, which will also affect the wearer's comfort and feasibility of long-term use. Summary of the invention

[0006] In order to address the shortcomings of the background technology, the present invention provides an under-actuated robot finger with a rigid-flexible hybrid transmission mechanism. The rigid-flexible hybrid transmission mechanism is combined with the under-actuated design to make the structure simpler and easier to operate, meet the requirements of anthropomorphic prosthetic fingers in terms of size, weight, integration and grasping envelope, and has the characteristics of coupled-adaptive motion, which greatly improves flexibility and comfort.

[0007] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an under-actuated robot finger with a rigid-flexible hybrid transmission mechanism, comprising a driving motor, a gear box, a connecting seat, a driving arm, a swing arm, a sliding rod, a finger joint shell and a fingertip assembly, wherein the driving motor housing is coaxially fixed to the bottom end of the gear box, and an active bevel gear and a driven bevel gear that mesh with each other are arranged inside the gear box, the active bevel gear is connected to the output shaft of the driving motor for transmission through a coupling, the driven bevel gear is connected to the worm through a key, and both ends of the worm are rotatably connected to the gear box through bearings, the connecting seat is fixedly arranged at the top of the gear box, a rotating shaft is fixedly installed in the middle position of the connecting seat, a worm gear is rotatably sleeved on the rotating shaft and meshed with the worm, the end of the finger joint shell is rotatably connected to the worm gear through a transfer bearing, the end of the swing arm is hinged to the front edge of the connecting seat through a pin shaft, and the top of the swing arm is extended to be The limiting groove is tilted backward and extends into the interior of the knuckle shell, the sliding rod is slidably installed in the limiting groove, the end of the driving arm is hinged to the rear edge of the worm gear surface through a pin shaft, and the top of the driving arm is hinged to the inner end of the sliding rod through a connecting pin. The fingertip assembly includes a flexible base and a rigid frame, the flexible base is made into the surface of the finger pad and a frame structure is arranged on its back side, the frame structure is composed of six sections of sheet frames arranged at intervals along the length direction, among which the first two sections of the sheet frames at the tip are integrally formed with the flexible base, and the remaining four sections of the sheet frames adopt the rigid frame and are fixed to the flexible base, the end of the flexible base is fixed with a connecting ear and is hinged to the top of the knuckle shell through a joint axis, springs are respectively arranged between the ends of two adjacent sections of the sheet frames, and a rigid support rod is hingedly arranged at the outer end of the sliding rod, and the free end of the rigid support rod is inserted through each spring in turn and supports the corresponding position of the sheet frame embedded in the tip.

[0008] Furthermore, an encoder is fixedly mounted on the bottom of the driving motor.

[0009] Furthermore, a resistive pressure sensor is fixedly installed on the front side of the outer wall of the knuckle shell to measure the contact signal with the grasped object.

[0010] Furthermore, a position sensor is fixedly installed at the end of the knuckle housing to measure the relative rotational position information between the worm gear and the knuckle housing.

[0011] Furthermore, a sliding sleeve is installed inside the open end of the limiting groove.

[0012] Furthermore, a strain gauge is installed between the first two sections of the sheet-like skeleton in the skeleton structure of the fingertip assembly to measure the flexible deformation information.

[0013] Furthermore, a fixed adapter is installed between the hinged end of the rigid support rod and the joint axis to maintain the stability of the relative position.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The present invention is based on the requirements of humanoid prosthetic fingers in terms of size, weight, integration and grasping envelope. By combining a rigid-flexible hybrid transmission mechanism with an under-actuated design, the structure is more compact, the complexity of the traditional drive system and control system is reduced, thereby significantly reducing the overall cost, making the robot finger structure simpler and easier to use, and having the characteristics of grasping adaptation and proportional coupled motion of the mechanism.

[0016] 2. The robot finger of the present invention has a coupling-adaptive motion function, which is specifically manifested as follows:

[0017] Anthropomorphic coupled motion in free space: When not in contact with the grasped object, the rotation of the knuckles and the deformation of the flexible base of the fingertips are linked in a fixed ratio, presenting an anthropomorphic pre-grasping action;

[0018] Adaptive movement after the knuckles touch the object: After the knuckles touch the grasped object, they stop moving, while the flexible base of the fingertips can continue to bend and deform, achieving adaptive enveloping grasping of the object.

[0019] In summary, the robot finger of the present invention exhibits significant advantages in anthropomorphic design, anthropomorphic size, low cost and light weight, and can greatly improve flexibility and comfort while ensuring efficient operation as a prosthetic finger. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the robot finger of the present invention;

[0021] Figure 2 It is an axonometric schematic diagram of the fingertip assembly of the robot finger of the present invention.

[0022] In the figure: 1. driving motor; 2. coupling; 3. screw; 4. active bevel gear; 5. gear box; 6. bearing one; 7. bearing two; 8. connecting seat; 9. worm; 10. bearing three; 11. driven bevel gear; 12. worm gear; 13. pin one; 14. driving arm; 15. pin two; 16. rotating shaft; 17. swing arm; 18. connecting pin; 19. limiting groove; 20. sliding sleeve; 21. resistive pressure sensor; 22. flexible substrate; 23. strain gauge; 24. position sensor; 25. sliding rod; 26. knuckle shell; 27. rigid support rod; 28. spring one; 29. ​​spring two; 30. spring three; 31. spring four; 32. spring five; 33. encoder; 34. rigid skeleton; 35. joint shaft; 36. adapter. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] like Figure 1-2 As shown, an underactuated robot finger with a rigid-flexible hybrid transmission mechanism includes a drive motor 1, a coupling 2, a screw 3, an active bevel gear 4, a gear box 5, a bearing 1 6, a bearing 2 7, a connecting seat 8, a worm 9, a bearing 3 10, a driven bevel gear 11, a worm wheel 12, a pin 1 13, a drive arm 14, a pin 2 15, a rotating shaft 16, a swing arm 17, a connecting pin 18, a limit groove 19, a sleeve 20, a resistive pressure sensor 21, a flexible substrate 22, a strain gauge 23, a position sensor 24, a sliding rod 25, a finger joint shell 26, a rigid support rod 27, a spring 1 28, a spring 2 29, a spring 3 30, a spring 4 31, a spring 5 32, an encoder 33, a rigid skeleton 34, a joint shaft 35 and an adapter 36.

[0025] Combination Figure 1As shown, the housing of the driving motor 1 is coaxially fixed with the bottom of the gear box 5 by screws 3, and an encoder 33 is fixedly installed at the bottom of the driving motor 1. The gear box 5 is provided with a driving bevel gear 4 and a driven bevel gear 11 that mesh with each other to transmit the motion and force output by the driving motor 1. The driving bevel gear 4 is connected to the output shaft of the driving motor 1 through a coupling 2 for transmission. The coupling 2 is rotatably connected to the gear box 5 through a bearing 2 7. The two ends of the worm 9 are rotatably connected to the gear box 5 through bearings 1 6 and 3 10 respectively. The driven bevel gear 11 is connected to the worm 9 by a key. The connecting seat 8 is fixedly arranged at the top of the gear box 5, and a rotating shaft 16 is fixedly installed in the middle of the connecting seat 8. The worm wheel 12 is rotatably sleeved on the rotating shaft 16 and meshes with the worm 9 to transmit the motion and force output by the driven bevel gear 11. The knuckle shell 26 is a hollow structure and a connecting piece is provided at its end and is rotatably connected to the worm gear 12 through an adapter bearing. A resistive pressure sensor 21 is fixedly installed on the front side of the outer wall of the knuckle shell 26 to measure the contact signal with the grasped object. A position sensor 24 is fixedly installed on the connecting piece at the end of the knuckle shell 26 to measure the relative rotation position information of the worm gear 12 and the knuckle shell 26. The end of the swing arm 17 is hinged with the pin shaft 2 15 fixedly installed on the front edge of the connecting seat 8 to form a rotation pair. The top of the swing arm 17 is extended to form a limit groove 19 and tilted backward to extend into the inside of the knuckle shell 26. A sliding sleeve 20 is installed inside the open end of the limit groove 19. The slide rod 25 is slidably installed in the limit groove 19 to form a sliding pair. The end of the drive arm 14 is hinged with the pin shaft 13 fixedly installed on the rear edge of the surface of the worm gear 12 to form a rotation pair. The top of the drive arm 14 is hinged with the inner end of the slide rod 25 through a connecting pin 18.

[0026] Combination Figure 1-2As shown, a fingertip assembly is installed at the top of the knuckle shell 26, and the fingertip assembly is composed of a flexible substrate 22 and a rigid skeleton 34. The flexible substrate 22 is made of a flexible material to form the surface of the finger pad and a skeleton structure is arranged on the back thereof. The skeleton structure is composed of six sections of sheet skeletons arranged at intervals along the length direction, wherein the first two sections of the sheet skeleton at the tip are integrally formed with the flexible substrate 22 using the same material, and a strain gauge 23 is installed between the first two sections of the sheet skeleton to measure the flexible deformation information, and the remaining four sections of the sheet skeleton adopt the rigid skeleton 34 and are fixed to the flexible substrate 22 as a whole. A connecting ear is fixed at the end of the flexible substrate 22 and is hinged to the top of the knuckle shell 26 through a joint axis 35 to form a revolving pair, so that the fingertip assembly can rotate relative to the knuckle shell 26 around the joint axis 35. In the skeleton structure, except for the sheet skeleton at the tip, a through hole is opened at the center of the end, and springs 1 28, 29, 30, 4 31 and 5 32 are arranged in sequence between the ends of two adjacent sections of the sheet skeleton from the end to the front. A rigid support rod 27 is hingedly provided at the outer end of the slide rod 25, and the free end of the rigid support rod 27 is sequentially inserted through the through holes of each sheet-like frame in the skeleton structure and spring 1 28, spring 29, spring 30, spring 4 31, and spring 5 32, and supports the corresponding position of the sheet-like frame embedded at the tip to transmit the movement and force from the slide rod 25. In addition, a fixed adapter 36 is installed between the hinged end of the rigid support rod 27 and the joint shaft 35 to keep the relative position between the hinged end of the rigid support rod 27 and the joint shaft 35 stable.

[0027] The innovation of the robot finger of the present invention is:

[0028] Rigid-flexible hybrid transmission mechanism: A hybrid transmission mechanism that combines rigid and flexible materials is used. Under the support of the rigid structure, the flexible structure is responsible for transmitting and regulating movement, thereby realizing the coordinated movement of multiple degrees of freedom of the fingers. This design can significantly improve the flexibility and adaptability of the fingers while ensuring the stability and reliability of the structure. Compared with traditional hardware drives, the rigid-flexible hybrid transmission mechanism can achieve natural grasping movement without adding too much weight and complexity;

[0029] Under-actuated design: The under-actuated design reduces the number of drive components and uses the synergy of the transmission mechanism to achieve joint motion control, which helps to further reduce costs and weight. Compared with traditional drive designs, it can achieve coordinated motion of more joints with less drive resources, making the movement of fingers smoother and more precise.

[0030] Humanoid size and natural finger movement, low cost and light weight: Through size design and structural planning, prosthetic fingers can better fit the size proportions of the human hand, making the finger length, joint angle, inter-knuckle distance, etc. closer to the natural structure of human fingers. Through the optimized design of the rigid-flexible hybrid transmission mechanism, the complexity of the motor, transmission components and control system in the traditional drive system is reduced, thereby significantly reducing the overall cost. The structure is simpler and easier to use, and the design is compact, which helps to effectively reduce the overall weight of the fingers. The wearer can maintain a high level of comfort during long-term use and avoid fatigue caused by excessive weight.

[0031] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms of assembly without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0032] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An underactuated robot finger with a rigid-flexible hybrid transmission mechanism, characterized in that: The invention comprises a driving motor (1), a gear box (5), a connecting seat (8), a driving arm (14), a swing arm (17), a sliding rod (25), a finger joint housing (26) and a finger tip assembly. The housing of the driving motor (1) is coaxially fixed to the bottom end of the gear box (5). An active bevel gear (4) and a driven bevel gear (11) that mesh with each other are arranged inside the gear box (5). The active bevel gear (4) is connected to the output shaft of the driving motor (1) through a coupling (2). The driven bevel gear (11) is connected to a worm (9) through a key. The worm (9) is connected to the driven bevel gear (11) through a key. The two ends of the rod (9) are rotatably connected to the gear box (5) through bearings, the connecting seat (8) is fixedly arranged at the top of the gear box (5), the middle position of the connecting seat (8) is fixedly installed with a rotating shaft (16), the rotating shaft (16) is rotatably sleeved with a worm wheel (12) and meshed with the worm (9), the end of the finger joint housing (26) is rotatably connected to the worm wheel (12) through a transfer bearing, the end of the swing arm (17) is hinged to the front side edge of the connecting seat (8) through a second pin shaft (15), and a limit groove (19) is extended from the top of the swing arm (17) and extends backward. The fingertip assembly is obliquely extended into the interior of the finger joint housing (26), the slide bar (25) is slidably installed in the limit groove (19), the end of the drive arm (14) is hinged to the rear edge of the surface of the worm gear (12) through a pin shaft (13), and the top of the drive arm (14) is hinged to the inner end of the slide bar (25) through a connecting pin (18). The fingertip assembly includes a flexible substrate (22) and a rigid skeleton (34), the flexible substrate (22) is made into the surface of the finger pad and a skeleton structure is arranged on the back side thereof, and the skeleton structure is composed of six sections of sheet skeletons arranged at intervals along the length direction. The first two sections of the sheet-like skeleton at the tip are integrally formed with the flexible base (22), and the remaining four sections of the sheet-like skeleton adopt the rigid skeleton (34) and are fixed to the flexible base (22). A connecting ear is fixed to the end of the flexible base (22) and is hinged to the top of the finger joint shell (26) through a joint shaft (35). Springs are respectively arranged between the ends of two adjacent sections of the sheet-like skeleton. A rigid support rod (27) is hingedly arranged at the outer end of the slide rod (25). The free end of the rigid support rod (27) is sequentially inserted through each spring and supports the corresponding position of the sheet-like skeleton embedded in the tip.

2. The underactuated robot finger with a rigid-flexible hybrid transmission mechanism according to claim 1, characterized in that: An encoder (33) is fixedly mounted on the bottom of the driving motor (1).

3. The underactuated robot finger with a rigid-flexible hybrid transmission mechanism according to claim 1, characterized in that: A resistive pressure sensor (21) is fixedly mounted on the front side of the outer wall of the knuckle housing (26) to measure a contact signal with the grasped object.

4. The underactuated robot finger with a rigid-flexible hybrid transmission mechanism according to claim 1, characterized in that: A position sensor (24) is fixedly mounted on the end of the knuckle housing (26) to measure relative rotational position information between the worm gear (12) and the knuckle housing (26).

5. The underactuated robot finger with a rigid-flexible hybrid transmission mechanism according to claim 1, characterized in that: A sliding sleeve (20) is installed inside the opening end of the limiting groove (19).

6. The underactuated robot finger with a rigid-flexible hybrid transmission mechanism according to claim 1, characterized in that: A strain gauge (23) is installed between the first two sections of the sheet-like skeleton in the skeleton structure of the fingertip assembly to measure flexible deformation information.

7. The underactuated robot finger with a rigid-flexible hybrid transmission mechanism according to claim 1, characterized in that: A fixed adapter (36) is installed between the hinged end of the rigid support rod (27) and the joint shaft (35) to maintain the stability of the relative position.

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