A flexible bionic finger

Abstract

The application discloses a flexible bionic finger and relates to the technical field of bionic robots, which comprises a finger body, a side swing structure and a driving mechanism which are integrally formed by using a flexible material. The finger body has a first base and at least two knuckles which are sequentially distributed along the length direction of the finger body. The adjacent knuckles and the relative rotating bodies between the knuckles and the first base are connected through a connecting mechanism. The connecting mechanism comprises a joint cross-bar structure and an elastic energy storage structure which is located on the back of the finger body. The joint cross-bar structure is composed of a first connecting rod and two parallel second connecting rods which are mutually inclined, so that the input motion and force at the first base are transmitted and enlarged to the end of the knuckle, and the local stress is reduced. The elastic energy storage structure stores energy when the finger is bent, and quickly rebounds when the driving is released. The elastic beam of the side swing structure allows the finger to laterally spread out. The driving mechanism drives the knuckle movement through a driving rope. The application improves the fatigue life, motion reliability and dynamic response speed of the finger.

Description

Technical Field

[0001] This invention relates to the field of bionic robot technology, and in particular to a flexible bionic finger. Background Technology

[0002] With the development of bionic robots, flexible bionic fingers, as a key component for achieving fine manipulation, are widely used in service robots, bionic prostheses and other fields due to the flexibility and safety of their materials. Their structural reliability, dynamic response efficiency and environmental interaction capabilities have become the core of technological breakthroughs.

[0003] Existing flexible bionic finger technology has long faced a fundamental contradiction: one-piece molding processes struggle to simultaneously guarantee reliable dexterity, while highly biomimetic multi-degree-of-freedom designs often rely on cumbersome modular assembly. This trade-off between "integration" and "reliability" directly leads to numerous drawbacks of existing one-piece molded fingers, such as:

[0004] Patent CN120382510A discloses a spiral flexible gripper that is driven by tendons. However, due to its logarithmic spiral structure, the fingers are not biomimetic enough to humans and cannot be used to grasp small objects. Furthermore, it relies solely on the passive rebound of its own flexible material properties and lacks an active or auxiliary rebound mechanism, resulting in a slow response speed. Moreover, it lacks vibration damping design at the rebound endpoint, which easily generates continuous oscillations and affects the gripping stability.

[0005] Patent CN109172063A discloses a rigid-flexible coupling bionic prosthetic hand for upper limb amputees. The flexible finger mechanism is connected to an elastic steel sheet and a linear actuator motor, with the steel sheet driving the finger's bending and extension. The finger's flexibility depends on the deformation of the elastic steel sheet at its root, which poses a risk of metal fatigue fracture after repeated bending. Furthermore, the deformation and recovery exhibit elastic hysteresis, leading to decreased control precision and slower response.

[0006] Patent CN117359666A discloses a structure that uses a bionic finger module and a bionic flexible body coupling part printed in one piece, which can greatly reduce the assembly complexity caused by the separate design. However, the pneumatic device is installed on the fingertip, which will affect the grasping task of the dexterous hand. Furthermore, the air vents and the connection port of the pneumatic device are prone to air leakage or structural breakage due to stress concentration during repeated bending, making fault diagnosis and maintenance more difficult. Summary of the Invention

[0007] The purpose of this invention is to provide a flexible bionic finger to solve the problems existing in the prior art, and to improve reliability by using a finger body that can be molded in one piece.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] This invention provides a flexible bionic finger, comprising:

[0010] The finger body is integrally molded from a flexible material. The finger body includes a first base and at least two phalanges distributed sequentially along its length. Both the first base and the phalanges are referred to as relative rotating bodies. Any two adjacent relative rotating bodies are connected by a connecting mechanism. The connecting mechanism includes a joint crossbar structure and an elastic energy storage structure. The joint crossbar structure includes a first connecting rod and two parallel second connecting rods. The first and second connecting rods are inclined relative to each other. One end of each of the first and second connecting rods, and the elastic energy storage structure, is fixedly connected to one of the relative rotating bodies, and the other end is fixedly connected to the other relative rotating body. Each elastic energy storage structure is located on the back of the finger body.

[0011] A side-swing structure, comprising an elastic beam, one end of which is fixedly connected to the first base, and the side-swing structure being able to extend outward along the thickness direction of the finger;

[0012] The driving mechanism includes a driving device, a reel, and a driving rope. The driving device is fixed on a second base and is used to drive the reel to rotate. The second base is fixedly connected to the other end of the elastic beam. The driving rope is wound around the reel. The phalanx furthest from the first base is the distal phalanx, and all the phalanges passing between the distal phalanx and the first base are intermediate phalanges. The free end of the driving rope is fixedly connected to the distal phalanx and passes through all the intermediate phalanges, and the driving rope slides with all the intermediate phalanges.

[0013] Preferably, in the same articulated crossbar structure, the first connecting rod is located between two second connecting rods, and there is a gap between the first connecting rod and the adjacent second connecting rod.

[0014] Preferably, the elastic energy storage structure includes a first elastic body, a second elastic body, and a third elastic body connected in sequence. The first elastic body and the third elastic body are located on the same side of the second elastic body. The first elastic body is fixedly connected to one of the relative rotating bodies and fixedly connected to another relative rotating body.

[0015] Preferably, a guide contact structure is provided between any two adjacent relative rotating bodies, the guide contact structure including toothed guide contact surfaces respectively provided on the two relative rotating bodies and rollingly engaging with each other.

[0016] Preferably, it also includes a cable box fixedly connected to the second base, and the cable reel is disposed inside the cable box.

[0017] Preferably, the elastic beam includes a first strip, a connecting portion, and a second strip that are sequentially distributed and connected from the first base to the second base, wherein the width of the first strip and the width of the second strip gradually decrease towards the connecting portion.

[0018] Preferably, each of the finger bones is provided with a perforation hole.

[0019] Preferably, the material of the finger body is thermoplastic polyurethane and polyether block amide.

[0020] Preferably, the number of finger bones is three or two.

[0021] Preferably, the guiding contact structure is located on the abdomen of the finger body.

[0022] The present invention achieves the following technical effects compared to the prior art:

[0023] The flexible bionic finger of this invention features a finger body that can be integrally formed using flexible materials through 3D printing. Multiple interlocking joint structures disperse the relative rotation between phalanges during finger movement to multiple micro-flexible hinges. Each hinge rotates a small angle, resulting in a larger overall rotation angle, significantly reducing the stress amplitude of individual hinges and improving fatigue life. The toothed guiding contact structure converts sliding friction into rolling contact, reducing stress and strain while fundamentally minimizing wear, further ensuring long-term reliability. The elastic energy storage structure works in conjunction with the flexible material; its mechanical instantaneous energy release mechanism offers a significant advantage in response hysteresis compared to traditional pneumatic solutions, achieving millisecond-level rebound. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the flexible bionic finger of the present invention;

[0026] Figure 2 This is a partial structural diagram of the flexible bionic finger of the present invention. Figure 1 ;

[0027] Figure 3 This is a partial structural diagram of the flexible bionic finger of the present invention. Figure 2 ;

[0028] In the diagram: 100, Flexible bionic finger; 10, Finger body; 1, Finger bone; 2, First base; 3, Drive device; 4, Second base; 5, Wire box; 6, Wire reel; 7, First elastic body; 8, Second elastic body; 9, Third elastic body; 11, Elastic energy storage structure; 12, Toothed guide contact surface; 13, Hollow hole; 14, Second connecting rod; 15, First connecting rod; 16, Drive rope; 20, Elastic beam; 201, First strip; 202, Connecting part; 203, Second strip; 30, Joint cross rod structure. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The purpose of this invention is to provide a flexible bionic finger to solve the problems existing in the prior art, and to improve reliability by using a finger body that can be molded in one piece.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] like Figures 1 to 3 As shown, this embodiment provides a flexible bionic finger 100, the core of which lies in achieving high reliability, rapid response, and multi-degree-of-freedom movement through a one-piece molded finger body 10 combined with a joint crossbar structure 30 and an elastic energy storage structure 11. The finger body 10 is integrally molded using flexible materials (such as thermoplastic polyurethane TPU or polyether block amide PEBA) through 3D printing technology, avoiding the structural weaknesses and complexities caused by separate assembly. The flexible bionic finger 100 includes the finger body 10, a lateral swing structure, and a drive mechanism.

[0033] The specific structure of the finger body 10 is as follows:

[0034] The finger body 10 includes a first base 2 and at least two phalanges 1 (usually three or two phalanges, to simulate a human finger) distributed sequentially along its length. The first base 2 and each level of phalanges 1 are collectively referred to as "relative rotating bodies," and adjacent relative rotating bodies are flexibly connected by a connecting mechanism. Each phalange 1 is provided with a perforated hole 13.

[0035] Each connecting mechanism includes a joint crossbar structure 30 and an elastic energy storage structure 11.

[0036] The specific structure of the joint crossbar structure 30 is as follows:

[0037] The articulated crossbar structure 30 consists of a first connecting rod 15 and two parallel second connecting rods 14, with the first connecting rod 15 and the second connecting rods 14 arranged at a certain angle. Preferably, the first connecting rod 15 is located between the two second connecting rods 14, maintaining an appropriate interval. This design decomposes the overall rotation of the finger body 10 when it bends onto multiple articulated crossbar structures 30. The end of each connecting rod in the articulated crossbar structure 30 forms a micro-flexible hinge, so that each hinge only needs to bear a small angle of rotation, thereby significantly reducing the stress amplitude of a single hinge and improving fatigue life. It is worth noting that the reason why the end of each connecting rod forms a micro-flexible hinge is that each connecting rod has a larger cross-sectional area in the middle and a smaller cross-sectional area at both ends, that is, each connecting rod is "thick in the middle and thin at both ends". Therefore, when the finger body 10 bends, the overall rotation will mainly be reflected in the elastic deformation of the end of each connecting rod, and the end of the connecting rod generates a frictionless and backlash-free elastic support during elastic deformation, which belongs to a flexible hinge.

[0038] The specific structure of the flexible energy storage structure 11 is as follows:

[0039] An elastic energy storage structure 11 is provided on the back of each connecting mechanism (i.e., the back side of the finger). This structure includes a first elastic body 7, a second elastic body 8, and a third elastic body 9 connected in sequence, wherein the first elastic body 7 and the third elastic body 9 are located on the same side of the second elastic body 8. When the finger is bent, the elastic energy storage structure 11 is stretched to store elastic potential energy; when the driving force is released, the stored energy is rapidly released, driving the finger to quickly rebound to the straight position. This mechanical energy release mechanism overcomes the response hysteresis problem of traditional pneumatic drive or passive rebound structures, achieving millisecond-level rebound and effectively suppressing oscillation at the rebound endpoint.

[0040] In an optional embodiment, a preferred embodiment includes a guiding contact structure between adjacent rotating bodies (at the fingertip position). This structure comprises toothed guiding contact surfaces 12 respectively disposed on the two rotating bodies. These contact surfaces roll against each other when the finger is bent, transforming traditional sliding friction into rolling contact, significantly reducing wear and stress concentration, and further improving long-term reliability.

[0041] The specific structure of the side-swing structure is as follows:

[0042] The lateral swing structure includes an elastic beam 20, one end of which is fixedly connected to the first base 2 of the finger body 10. In this embodiment, the elastic beam 20 adopts a variable width design, including a first strip 201, a connecting portion 202, and a second strip 203 connected sequentially from the first base 2 to the second base 4, wherein the width of both the first strip 201 and the second strip 203 gradually decreases towards the connecting portion 202. This design allows the finger to laterally abduct outward with the thickness direction as the axis, increasing the finger's flexibility.

[0043] The specific structure of the drive mechanism is as follows:

[0044] The drive mechanism includes a drive unit 3 (such as a micro motor), a coil 6, and a drive rope 16. The drive unit 3 is fixed to the second base 4, which is fixedly connected to the free end of the elastic beam 20. The drive rope 16 is wound around the coil 6, and its free end passes through all the intermediate phalanges 1 (the phalanges 1 between the distal phalanges 1 and the first base 2) and is fixedly connected to the distal phalanges 1. When the drive unit 3 drives the coil 6 to rotate, the drive rope 16 is tightened, pulling each phalanx 1 to bend sequentially; when the coil 6 rotates in the opposite direction to release the drive rope 16, the energy stored in the elastic deformation of the micro flexible hinge at the end of the joint crossbar structure 30 and the elastic deformation of the elastic energy storage structure 11 is released, driving the finger to quickly rebound to the straight position. Moreover, by changing the output direction of the drive unit 3, the finger body 10 can be controlled to swing to the left or right. A wire box 5 is provided on the second base 4, and the coil 6 is disposed in the wire box 5.

[0045] The specific working principle of the flexible bionic finger 100 in this embodiment is as follows:

[0046] When the drive device 3 tightens the drive rope 16 via the reel 6, the traction force is transmitted from the distal phalanx 1 to the proximal phalanx 1, and each phalanx 1 bends sequentially under the guidance of the articulated crossbar structure 30. The articulated crossbar structure 30 decomposes the large-angle bending motion into multiple micro-rotations, significantly reducing local stress. At the same time, the magnetic contact surfaces in the guide contact structure maintain rolling contact during bending, further reducing friction and wear.

[0047] When the drive rope 16 is released, the elastic potential energy stored in the elastic energy storage structure 11 is rapidly released, driving each finger bone 1 to rebound quickly. Due to the nonlinear stiffness characteristics of the elastic energy storage structure 11, the stiffness increases at the end of the rebound process, effectively suppressing oscillation and enabling the fingers to quickly stabilize in the extended position.

[0048] When the output direction of the drive device 3 causes the force direction of the drive rope 16 to be vertically deflected to the right, the elastic beam 20 of the side-swing structure undergoes asymmetrical force and buckles elastically to the right, causing the entire flexible finger body 10 to extend outward to the right. When the servo motor causes the force direction of the drive rope 16 to be vertically deflected to the left, the elastic beam 20 of the side-swing structure undergoes asymmetrical force and buckles elastically to the left, causing the entire flexible finger body 10 to extend outward to the left.

[0049] This embodiment achieves high reliability, rapid response, and multi-degree-of-freedom motion by combining a one-piece molded finger body 10 with a joint crossbar structure 30, an elastic energy storage structure 11, and a guiding contact structure. This effectively resolves the contradiction between one-piece molding and motion reliability in existing flexible bionic fingers 100. It is particularly suitable for applications such as service robots and bionic prostheses requiring precise manipulation.

[0050] In the description of this invention, it should be noted that the terms "center," "top," "bottom," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A flexible bionic finger, characterized in that, include: The finger body is integrally molded from a flexible material. The finger body includes a first base and at least two phalanges arranged sequentially along its length. Both the first base and the phalanges are referred to as relative rotating bodies. Any two adjacent relative rotating bodies are connected by a connecting mechanism. The connecting mechanism includes a joint crossbar structure and an elastic energy storage structure. The joint crossbar structure includes a first connecting rod and two parallel second connecting rods. The first and second connecting rods are inclined relative to each other. One end of each of the first, second, and elastic energy storage structures is fixedly connected to one relative rotating body, and the other end is fixedly connected to the other relative rotating body. The first and second connecting rods are thicker in the middle and thinner at both ends. The ends of the first and second connecting rods form micro-flexible hinges. Each elastic energy storage structure is located on the back of the finger body. The elastic energy storage structure includes a first elastic body, a second elastic body, and a third elastic body connected sequentially. The first and third elastic bodies are located on the same side of the second elastic body. The first elastic body is fixedly connected to one relative rotating body, and the second elastic body is fixedly connected to the other relative rotating body. A side-swing structure, comprising an elastic beam, one end of which is fixedly connected to the first base, and the side-swing structure being able to extend outward along the thickness direction of the finger; The driving mechanism includes a driving device, a reel, and a driving rope. The driving device is fixed on a second base and is used to drive the reel to rotate. The second base is fixedly connected to the other end of the elastic beam. The driving rope is wound around the reel. The phalanx furthest from the first base is the distal phalanx, and all the phalanges passing between the distal phalanx and the first base are intermediate phalanges. The free end of the driving rope is fixedly connected to the distal phalanx and passes through all the intermediate phalanges, and the driving rope slides with all the intermediate phalanges.

2. The flexible bionic finger according to claim 1, characterized in that: In the same articulated crossbar structure, the first connecting rod is located between two second connecting rods, and there is a gap between the first connecting rod and the adjacent second connecting rod.

3. The flexible bionic finger according to claim 1, characterized in that: A guide contact structure is provided between any two adjacent relatively rotating bodies. The guide contact structure includes toothed guide contact surfaces respectively provided on the two relatively rotating bodies and rollingly engaging with each other.

4. The flexible bionic finger according to claim 1, characterized in that: It also includes a cable box that is fixedly connected to the second base, and the cable reel is disposed inside the cable box.

5. The flexible bionic finger according to claim 1, characterized in that: The elastic beam includes a first strip, a connecting portion, and a second strip that are sequentially distributed and connected from the first base to the second base. The width of the first strip and the width of the second strip gradually decrease towards the connecting portion.

6. The flexible bionic finger according to claim 1, characterized in that: Each of the aforementioned finger bones has a perforated hole.

7. The flexible bionic finger according to claim 1, characterized in that: The main body of the finger is made of thermoplastic polyurethane and polyether block amide.

8. The flexible bionic finger according to claim 1, characterized in that: The number of finger bones is three or two.

9. The flexible bionic finger according to claim 3, characterized in that: The guiding contact structure is located on the abdomen of the finger body.

Images