Flexible bionic finger

Abstract

The invention discloses a flexible bionic finger, which relates to the technical field of bionic robots and comprises a finger main body, a side-sway structure and a driving mechanism which are integrally formed by adopting a flexible material. The finger body is provided with a first base and at least two phalanges which are sequentially distributed in the length direction of the finger body, and the relative rotating bodies of the adjacent phalanges and the phalanges and the first base are connected through connecting mechanisms. The connecting mechanism comprises a joint cross rod structure and an elastic energy storage structure located on the back of the finger body. The joint cross rod structure is formed by mutually inclining a first connecting rod and two parallel second connecting rods, input motion and force at the position of the first base are transmitted and amplified to the tail ends of the knuckles, and local stress is reduced. The elastic energy storage structure stores energy when the finger is bent, and rebounds quickly when the drive is released. The elastic beams of the side-sway structure allow the fingers to laterally expand outwards. The driving mechanism pulls the phalanges to move through the driving rope. The fatigue life, the motion reliability and the dynamic response speed of the fingers are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bionic robots, in particular to a flexible bionic finger. BACKGROUND

[0002] With the development of bionic robots, flexible bionic fingers, as key components for achieving fine operations, are widely used in service robots, bionic prostheses and other fields due to their flexible materials and safety. The structural reliability, dynamic response efficiency and environmental interaction capability have become the core of technical breakthroughs.

[0003] The existing flexible bionic finger technology has long been plagued by a fundamental contradiction: the integrated forming process cannot balance reliable dexterous motion capability, and highly bionic multi-degree-of-freedom design often relies on tedious split assembly. This mutual exclusion of "integration" and "reliability" directly leads to many shortcomings of the existing one-piece fingers, such as: Patent CN120382510A discloses a spiral flexible gripper driven by tendon, but due to its logarithmic spiral structure, the finger as a whole is not bionic to humans and cannot be used for grasping small objects. It only relies on the passive rebound of its own flexible material properties, lacks active or auxiliary rebound mechanism, resulting in slow response speed, and lacks vibration suppression design at the rebound end, which is prone to continuous oscillation, affecting the stability of grasping.

[0004] Patent CN109172063A discloses a rigid-flexible coupled bionic artificial hand for upper limb amputees. The flexible finger mechanism is connected by elastic steel sheets and linear push rod motors, and the finger is bent and stretched by the steel sheets. The flexibility of the finger depends on the deformation of the elastic steel sheet at the root, which has the risk of metal fatigue fracture after repeated bending. At the same time, there is an elastic hysteresis phenomenon in the deformation and recovery, which will cause the control precision to decrease and the response to slow down.

[0005] Patent CN117359666A discloses a structure that integrates printing of bionic finger modules and bionic flexible coupling parts, which can greatly reduce the assembly complexity brought by split design. However, the pneumatic device is installed on the finger pulp, which will affect the grasping task of the dexterous hand. And the air hole and the connection port of the pneumatic device are prone to air leakage or structure fracture due to stress concentration during repeated bending, making fault diagnosis and maintenance more difficult. SUMMARY

[0006] The purpose of the present application is to provide a flexible bionic finger to solve the problems existing in the prior art and improve the reliability based on the use of a finger body that can be integrally formed.

[0007] To achieve the above purpose, the present application provides the following solutions: The present application provides a flexible bionic finger, comprising: The finger body is integrally formed by a flexible material; the finger body comprises a first base and at least two knuckles which are sequentially distributed along the length direction of the finger body, the first base and the knuckles are all called relative rotating bodies, any two adjacent relative rotating bodies are connected by a connecting mechanism, the connecting mechanism comprises a joint cross-bar structure and an elastic energy storage structure, the joint cross-bar structure comprises a first connecting rod and two second connecting rods which are arranged in parallel to each other, the first connecting rod and the second connecting rods are inclined to each other, the first connecting rod, the second connecting rods and the elastic energy storage structure are all fixedly connected at one end with one relative rotating body and at the other end with another relative rotating body; and each elastic energy storage structure is located on the back of the finger body. The side swing structure comprises an elastic beam, one end of the elastic beam is fixedly connected with the first base, and the side swing structure can be outwardly spread towards the thickness direction of the finger as the axis. The driving mechanism comprises a driving device, a wire reel and a driving rope, the driving device is fixedly arranged on the second base and used for driving the wire reel to rotate, the second base is fixedly connected with the other end of the elastic beam, the driving rope is wound on the wire reel, the farthest knuckle from the first base is a distal knuckle, all the knuckles between the distal knuckle and the first base are intermediate knuckles, the free end of the driving rope is fixedly connected with the distal knuckle and passes through all the intermediate knuckles, and the driving rope is in sliding fit with all the intermediate knuckles.

[0008] Preferably, in the same joint cross-bar structure, the first connecting rod is located between the two second connecting rods, and there is a space between the first connecting rod and the adjacent second connecting rod.

[0009] Preferably, the elastic energy storage structure comprises a first elastic body, a second elastic body and a third elastic body which are sequentially connected, 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 with one relative rotating body and the third elastic body is fixedly connected with another relative rotating body.

[0010] Preferably, a guide contact structure is arranged between any two adjacent relative rotating bodies, the guide contact structure comprises tooth-shaped guide contact surfaces which are arranged on the two relative rotating bodies respectively and in rolling fit with each other.

[0011] Preferably, the driving mechanism further comprises a wire box which is fixedly connected with the second base, and the wire reel is arranged in the wire box.

[0012] 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.

[0013] Preferably, each of the finger bones is provided with a perforation hole.

[0014] Preferably, the material of the finger body is thermoplastic polyurethane and polyether block amide.

[0015] Preferably, the number of finger bones is three or two.

[0016] Preferably, the guiding contact structure is located on the abdomen of the finger body.

[0017] The present invention achieves the following technical effects compared to the prior art: 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

[0018] 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.

[0019] Figure 1 This is a schematic diagram of the flexible bionic finger of the present invention; Figure 2 This is a partial structural diagram of the flexible bionic finger of the present invention. Figure One ; Figure 3 This is a partial structural diagram of the flexible bionic finger of the present invention. Figure Two ; 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

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] The specific structure of the finger body 10 is as follows: 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.

[0025] Each connecting mechanism includes a joint crossbar structure 30 and an elastic energy storage structure 11.

[0026] The specific structure of the joint crossbar structure 30 is as follows: 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.

[0027] The specific structure of the flexible energy storage structure 11 is as follows: 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.

[0028] 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.

[0029] The specific structure of the side-swing structure is as follows: 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.

[0030] The specific structure of the drive mechanism is as follows: 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.

[0031] The specific working principle of the flexible bionic finger 100 in this embodiment is as follows: 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 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. 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: 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 the third elastic body is fixedly connected to another relative rotating body.

4. 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.

5. 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.

6. 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.

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

8. 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.

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

10. The flexible bionic finger according to claim 4, characterized in that: The guiding contact structure is located on the abdomen of the finger body.

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