Rope-driven dexterous finger capable of actively changing length

Abstract

The invention belongs to the technical field of dexterous hands, and relates to a rope-driven initiative variable-length dexterous finger which comprises a first knuckle, a variable-length second knuckle, a variable-length third knuckle, a metacarpophalangeal joint and a far-end driver which are sequentially connected through a tendon rope. The joints of the first knuckles, the variable-length second knuckles, the variable-length third knuckles and the metacarpophalangeal joints are all of tangent rolling structures, the variable-length second knuckles and the variable-length third knuckles are all of elastic telescopic structures, when a far-end driver controls a traction tendon rope, the joints are in tangent fit through the tangent rolling structures, and lateral limiting relative rolling occurs; and on the basis of an elastic telescopic structure, the second variable-length knuckles and the third variable-length knuckles stretch out and draw back, so that the lengths of the fingers are changed. According to the flexible finger, flexible finger bending and variable-length independent actions with the light tail end and miniaturization can be achieved, the working space of the flexible finger is greatly enlarged, and the application range of the flexible finger is greatly widened.

Description

Technical Field

[0001] The invention belongs to the technical field of dexterous hands and relates to a dexterous finger with actively variable length driven by a rope. Background Art

[0002] In the existing dexterous hand designs, the applicable grasping objects are often greatly limited by the length of the fingers. Fingers that are too long cannot stably grasp small objects, and fingers that are too short cannot stably grasp large objects. For example, in the dexterous hand with detachable fingers in patent CN212825430U and the lightweight humanoid five-finger dexterous hand mechanism in patent CN107538510A, the finger parts are rigid parts with fixed lengths and fixed working spaces.

[0003] At the same time, the existing dexterous hand designs usually connect the finger joints through pins, which on the one hand ensures the stability of the connection between the knuckles. On the other hand, if a connecting rod drive is used to control the finger movements, the mechanism is complicated and the weight of the dexterous hand itself will often increase; if a rope drive is used, the force transmission efficiency of the pin-connected knuckles is poor. For example, the bionic three-finger manipulator of patent CN105522587B uses gear transmission to drive the finger movements, and the motor drives the swing arm through a reduction gear set, a screw, a slider, and a rack, but sacrifices the simplicity and weight of the mechanism; in the universal anthropomorphic five-finger dexterous hand of patent CN118269127A, a tendon rope drive is used to reduce the weight of the palm and fingers, and a number of tendon rope guides are used for constraint, but because the joints are still connected by rotation, the force transmission efficiency is lower than that of the rolling joints. Summary of the invention

[0004] In order to solve the above technical problems existing in the prior art, the present invention proposes a dexterous finger with active length change driven by rope, which can realize active control of finger length change and flexion movement by rope drive and rolling joint. The specific technical scheme is as follows: A dexterous finger with active variable length driven by a rope comprises: a tendon rope, a first knuckle, a second knuckle with variable length, a third knuckle with variable length, a metacarpophalangeal joint, and a remote driver, wherein the first knuckle, the second knuckle with variable length, the third knuckle with variable length, the metacarpophalangeal joint, and the remote driver are connected in sequence through the tendon rope, and the tendon ropes are arranged to be antagonistic to each other, and the connection between the first knuckle, the second knuckle with variable length, the third knuckle with variable length, and the metacarpophalangeal joint adopts a tangent rolling structure, and the second knuckle with variable length and the third knuckle with variable length are both elastic telescopic structures, comprising: a knuckle male head and a knuckle female head, a compression spring is arranged in the knuckle female head, the knuckle male head is inserted into the knuckle female head to elastically contact with the compression spring and is connected by a limited movement of a male and female nail; when the remote driver controls the pulling of the tendon rope, the tangent rolling structure makes the joints tangentially cooperate and relatively roll with lateral limitation occurs, thereby performing finger flexion; based on the elastic telescopic structure, the second knuckle with variable length and the third knuckle with variable length perform telescopic movements, thereby changing the finger length.

[0005] Furthermore, the first finger joint includes: a fingertip body, a fixing pin is provided inside the fingertip body, one end of the tendon rope is connected to the fixing pin, and a tongue arc surface structure is provided at the bottom of the arc surface of the fingertip body. Specifically, the tongue arc surface structure is an arc-shaped protrusion provided in the middle of the bottom of the arc surface.

[0006] Furthermore, the variable-length second knuckle includes: a second knuckle male head and a second knuckle female head. The top of the arc surface of the second knuckle male head is provided with a cavity arc surface structure, and the bottom of the arc surface of the second knuckle female head is provided with a tongue arc surface structure that is the same as that of the fingertip body; the cavity arc surface structure is specifically a concave cavity arranged in the middle of the top of the arc surface, and the bottom surface of the concave cavity is an arc-shaped convexity and is tangentially matched with the arc-shaped convexity when the knuckles are connected. After the variable-length second knuckle is connected to the first knuckle, the cavity arc surface structure and the tongue arc surface structure of the first knuckle are tangentially matched to form the tangential rolling structure.

[0007] Furthermore, second knuckle axial grooves are provided on both side outer walls of the second knuckle male head and the second knuckle female head, and the second knuckle axial grooves extend to the corresponding concave cavity and the arc-shaped protrusion respectively; the connection of the tendon rope is guided and constrained by the second knuckle axial grooves.

[0008] Furthermore, a mother-and-child nail hole and a mother-and-child nail groove are respectively provided on the second knuckle male head and the second knuckle female head, and a second knuckle compression spring is provided in the second knuckle female head. By inserting a mother-and-child nail into the mother-and-child nail hole and the mother-and-child nail groove, the second knuckle male head and the second knuckle female head can slide relative to each other in the axial direction for a limited distance after being assembled.

[0009] Furthermore, the variable-length third knuckle includes: a third knuckle male head and a third knuckle female head, and the axial lengths of the third knuckle male head and the third knuckle female head are respectively greater than the axial lengths of the second knuckle male head and the second knuckle female head.

[0010] Furthermore, the top of the metacarpophalangeal joint is connected to the variable-length third knuckle through a tangential rolling structure, and a metacarpophalangeal tongue joint structure is provided at the bottom of the metacarpophalangeal joint. The metacarpophalangeal tongue joint structure is cooperatively connected to the external palm part so that the metacarpophalangeal joint can swing in a direction perpendicular to the finger flexion direction.

[0011] Furthermore, the number of tendon ropes is 2, and the remote driver includes: a control circuit board, and two driving servos installed and connected to the control circuit board. The two driving servos are each connected to a tendon rope. The control circuit board gives angle control instructions to the driving servos through PWM signals, and then controls the flexion and extension of the fingers through the tendon ropes.

[0012] The fingers of the present invention actively control the lengths of two antagonistic tendon ropes. Under the constraints of the parent-child nail assembly and the compression spring in the second and third knuckles, the lightweight and miniaturized terminal dexterous fingers can be flexed and independently move in length, which greatly improves the working space and application range of the dexterous fingers. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic structural diagram of a rope-driven, actively variable-length dexterous finger of this embodiment; Figure 2 is a schematic structural diagram of the variable length second finger joint of this embodiment; Figure 3 is a schematic structural diagram of the variable length third finger joint of this embodiment; Figure 4 Schematic diagram of the structure of the metacarpophalangeal joint of this embodiment; In the figure: 1 is the first knuckle, 2 is the variable length second knuckle, 3 is the variable length third knuckle, 4 is the metacarpophalangeal joint, and 5 is the distal actuator; 10 is a fingertip body, 11 is a fixing pin; 21 is the male head of the second knuckle, 22 is the female head of the second knuckle, 23 is the axial groove of the second knuckle, 211 is the arc surface structure of the cavity, 212 is the mother-and-child nail hole, 221 is the mother-and-child nail groove, and 222 is the second knuckle compression spring; 31 is the male head of the third knuckle, 32 is the female head of the third knuckle, 33 is the axial groove of the third knuckle, 311 is the arc surface structure of the cavity of the third knuckle, 312 is the mother-and-child nail hole of the third knuckle, 321 is the mother-and-child nail groove of the third knuckle, and 322 is the compression spring of the third knuckle; 41 is the arc surface structure of the intercarpal and interphalangeal cavity; 42 is the intercarpal and interphalangeal axial groove; 43 is the intercarpal and interphalangeal tongue joint structure; 51 is a driving servo, and 52 is a control circuit board. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical scheme and technical effect of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0015] like Figures 1 to 4As shown, an embodiment of the present invention provides a dexterous finger with active variable length driven by a rope, comprising: a tendon rope, a first knuckle 1, a second knuckle 2 with variable length, a third knuckle 3 with variable length, a metacarpophalangeal joint 4, and a remote driver 5, wherein the first knuckle 1, the second knuckle 2 with variable length, the third knuckle 3 with variable length, the metacarpophalangeal joint 4, and the remote driver 5 are sequentially connected by the tendon rope, and the tendon ropes are arranged to be mutually antagonistic, so that each knuckle is coupled with each other. The connection between the first knuckle 1, the second knuckle 2 with variable length, the third knuckle 3 with variable length, and the metacarpophalangeal joint 4 is designed as a tangent rolling structure, through which the joints are tangently matched, relative rolling between the joints is achieved, and lateral limiting is performed at the same time, so as to stably complete the flexion action of the finger. The second knuckle 2 with variable length and the third knuckle 3 with variable length are both designed as elastic telescopic structures to achieve the change of the length of the finger, and the elastic telescopic structure comprises: a knuckle male head and a knuckle female head, a compression spring is arranged in the knuckle female head, the knuckle male head is inserted into the knuckle female head and elastically conflicts with the compression spring and is connected by the limited movement of the male and female nails.

[0016] Specifically, the first finger joint 1 includes: a fingertip body 10, a fixing pin 11 is arranged inside the fingertip body 10, one end of the tendon rope is connected to the fixing pin 11, and a tongue arc surface structure is arranged at the bottom of the arc surface of the fingertip body 10. The tongue arc surface structure is specifically an arc-shaped protrusion, namely the tongue, arranged in the middle of the bottom of the arc surface.

[0017] Continue to refer Figure 2The variable length second knuckle 2 is connected to the lower part of the first knuckle 1, and includes: a second knuckle male head 21, a second knuckle female head 22, a cavity arc surface structure 211 is provided at the top of the circular arc surface of the second knuckle male head 21, and the cavity arc surface structure 211 is specifically a concave cavity provided in the middle of the top of the circular arc surface, and the bottom surface of the concave cavity is an arc-shaped protrusion and is tangentially matched with the corresponding arc-shaped protrusion when the knuckles are connected, so that after the two knuckles are connected, the cavity arc surface structure 211 and the tongue arc surface structure of the first knuckle 1 can be tangentially matched to form the tangential rolling structure. The bottom of the circular arc surface of the second knuckle female head 22 is provided with a tongue arc surface structure that is the same as the fingertip body 10. The second knuckle axial groove 23 is provided on the outer walls of both sides of the second knuckle male head 21 and the second knuckle female head 22, and the second knuckle axial groove 23 extends to the corresponding concave cavity and the arc-shaped protrusion respectively, and the second knuckle axial groove 23 is used to guide the rope path of the restraining tendon rope. The variable length second knuckle 2 is pulled and coordinated with the first knuckle 1 by the tendon rope, and the relative rolling of the two is achieved based on the tangential rolling structure, so that the straight state of the finger is maintained at the low point of potential energy, and the stability and reset accuracy of the finger posture can be guaranteed when the tendon rope is tightened. The second knuckle male head 21 and the second knuckle female head 22 are respectively provided with a mother-and-child nail hole 212 and a mother-and-child nail groove 221, and a second knuckle compression spring 222 is provided in the second knuckle female head 22. After the mother-and-child nails are inserted into the mother-and-child nail holes 212 and the mother-and-child nail groove 221, the second knuckle male head 21 and the second knuckle female head 22 can be assembled to perform limited relative sliding in the axial direction. The second knuckle compression spring 222 can provide mechanical constraints for the variable length control of the knuckle after pre-compression.

[0018] Continue to refer Figure 3, the variable length third knuckle 3 is only longer in axial length than the variable length second knuckle 2, and the other structures and connection components are the same, including: a third knuckle male head 31, a third knuckle female head 32, and a three-knuckle cavity arc surface structure 311 is provided on the third knuckle male head 31, which is tangentially matched with the tongue arc surface structure of the second knuckle female head 22. A tongue arc surface structure is provided at the bottom of the third knuckle female head 32. A third knuckle axial groove 33 is provided on the outer walls on both sides of the male and female heads, and the variable length third knuckle 3 and the variable length second knuckle 2 are driven by tendon rope traction to make them roll relative to each other. The third knuckle male head 31 and the third knuckle female head 32 are respectively provided with a three-knuckle mother-and-child nail hole 312 and a three-knuckle mother-and-child nail groove 321, and a third knuckle compression spring 322 is provided in the third knuckle female head 32. In this embodiment, the axial length of the third knuckle male head 31 and the third knuckle female head 32 is 10 mm longer than that of the second knuckle male head 21 and the second knuckle female head 22, so that the grasping action and working space of the dexterous fingers can be close to the characteristics of human hands when the lengths of the knuckles change at the same time, and objects of different sizes can be grasped stably by changing the length of the knuckles. The two variable-length knuckles of the present invention are radially slidably arranged by geometric configuration during assembly, and their axial displacement and mechanical characteristics are limited by the configured mother-and-child nail assembly and the compression spring placed in the second knuckle female head.

[0019] Continue to refer Figure 4 The top of the arc surface of the metacarpophalangeal joint 4 is provided with an intermecarpophalangeal cavity arc surface structure 41, and the intermecarpophalangeal cavity arc surface structure 41 is tangently matched with the tongue arc surface structure of the third knuckle female head 32. The outer walls on both sides of the metacarpophalangeal joint 4 are provided with intermecarpophalangeal axial grooves 42, and the intermecarpophalangeal axial grooves 42 extend to the arc-shaped concave cavity of the intermecarpophalangeal cavity arc surface structure 41. The bottom of the metacarpophalangeal joint 4 is provided with an intermecarpophalangeal tongue joint structure 43, and the tongue of the intermecarpophalangeal tongue joint structure 43 is vertically arranged with the tongue of the tongue arc surface structure in a spatial angle, and the intermecarpophalangeal tongue joint structure 43 and the external palm part are connected in coordination. The external palm part can be any rigid body with a matching geometric shape. This structure provides passive lateral swing freedom for the fingers.

[0020] The remote driver 5 includes: a driving servo 51 and a control circuit board 52. Two tendons are used for one finger of this embodiment. One end of the two tendons is connected to the fixed pin 11, and the other end passes through the tangent rolling structure and axial groove of each knuckle in turn. At the same time, the two tendons are set to be mutually antagonistic, so that the knuckles are coupled with each other, and finally connected to the driving motor 51, which is driven by the driving motor 51. The flexion of the finger and the length change of the second and third knuckles are controlled by the coupling relationship of the length of the two tendons. The control circuit board 52 is fixedly connected to the two driving servos 51 by gluing. The control circuit board 52 gives the angle control command of the driving servo 51 through the PWM signal, thereby controlling the length of the tendons, the flexion of the fingers and the extension and contraction of the knuckles. The remote driver 5 is located at a fixed end outside the fingers and palms. This design makes the fingers and palms lightweight and miniaturized, and integrates the driving and control parts in the same area, which helps to enhance the overall versatility of the dexterous hand.

[0021] In summary, in the present invention, the first phalanx 1, the variable-length second phalanx 2, and the variable-length third phalanx 3 each have a flexion and extension degree of freedom and are coupled to each other by the action of the tendon rope; the metacarpophalangeal joint 4 has a passive lateral swing degree of freedom; the variable-length second phalanx 2 and the variable-length third phalanx 3 each have an axial extension degree of freedom. Therefore, the design of the present invention realizes the flexion and variable-length independent action of the lightweight and miniaturized dexterous fingers at the end, greatly improving the working space and application range of the dexterous fingers.

[0022] It should be noted that all directional indications in this embodiment (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly. In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixed", etc. should be understood in a broad sense. For example, "fixed" can be a fixed connection, a detachable connection, or an integral whole; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] The above is only a preferred implementation case of the present invention and does not limit the present invention in any form. Although the implementation process of the present invention is described in detail above, for those familiar with the art, they can still modify the technical solutions recorded in the above examples, or replace some of the technical features therein with equivalents. All modifications, equivalent replacements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dexterous finger with active variable length driven by a rope, comprising: A tendon rope, a first finger joint (1), a variable-length second finger joint (2), a variable-length third finger joint (3), a metacarpophalangeal joint (4), and a remote driver (5), wherein the first finger joint (1), the variable-length second finger joint (2), the variable-length third finger joint (3), the metacarpophalangeal joint (4), and the remote driver (5) are connected in sequence through the tendon rope, characterized in that: The connection points of the first knuckle (1), the variable-length second knuckle (2), the variable-length third knuckle (3), and the metacarpophalangeal joint (4) all adopt a tangent rolling structure, and the variable-length second knuckle (2) and the variable-length third knuckle (3) are both elastic telescopic structures, including: a knuckle male head and a knuckle female head, a compression spring is arranged in the knuckle female head, the knuckle male head is inserted into the knuckle female head to elastically contact with the compression spring, and is connected by limited movement through a male-female nail; When the distal driver (5) controls the traction tendon rope, the tangential rolling structure causes the joints to cooperate tangentially and to roll relative to each other with lateral limitation, thereby performing a finger flexion action; based on the elastic telescopic structure, the variable-length second finger joint (2) and the variable-length third finger joint (3) perform a telescopic action, thereby changing the finger length.

2. The dexterous finger according to claim 1, characterized in that: The first finger joint (1) comprises: a fingertip body (10), a fixing pin (11) is arranged inside the fingertip body (10), one end of the tendon rope is connected to the fixing pin (11), and a tongue arc surface structure is arranged at the bottom of the circular arc surface of the fingertip body (10), and the tongue arc surface structure specifically comprises an arc-shaped protrusion arranged in the middle of the bottom of the circular arc surface.

3. The dexterous finger according to claim 2, characterized in that: The variable-length second finger joint (2) comprises: a second finger joint male head (21) and a second finger joint female head (22); the top of the circular arc surface of the second finger joint male head (21) is provided with a cavity arc surface structure (211), and the bottom of the circular arc surface of the second finger joint female head (22) is provided with a tongue arc surface structure that is the same as the fingertip body (10); the cavity arc surface structure (211) is specifically a concave cavity provided in the middle of the top of the circular arc surface, and the bottom surface of the concave cavity is an arc-shaped protrusion and is tangentially matched with the arc-shaped protrusion when the fingers are connected. After the variable-length second finger joint (2) is connected to the first finger joint (1), the cavity arc surface structure (211) and the tongue arc surface structure of the first finger joint (1) are tangentially matched to form the tangential rolling structure.

4. The dexterous finger according to claim 3, characterized in that: Second knuckle axial grooves (23) are provided on both side outer walls of the second knuckle male head (21) and the second knuckle female head (22), and the second knuckle axial grooves (23) extend to the corresponding concave cavity and the arc-shaped protrusion respectively; the connection of the tendon rope is guided and constrained by the second knuckle axial grooves (23).

5. The dexterous finger according to claim 3, characterized in that: A second finger joint male head (21) and a second finger joint female head (22) are respectively provided with a finger nail hole (212) and a finger nail groove (221); a second finger joint compression spring (222) is arranged in the second finger joint female head (22); and the finger nail is inserted into the finger nail hole (212) and the finger nail groove (221) so that the second finger joint male head (21) and the second finger joint female head (22) can slide relative to each other in the axial direction over a limited distance after being assembled.

6. The dexterous finger according to claim 3, characterized in that: The variable-length third finger joint (3) comprises: a third finger joint male head (31) and a third finger joint female head (32); the axial lengths of the third finger joint male head (31) and the third finger joint female head (32) are respectively greater than the axial lengths of the second finger joint male head (21) and the second finger joint female head (22).

7. The dexterous finger according to claim 1, characterized in that: The top of the metacarpophalangeal joint (4) is connected to the variable-length third finger joint (3) via a tangential rolling structure, and the bottom of the metacarpophalangeal joint (4) is provided with a metacarpophalangeal tongue joint structure (43), which is cooperatively connected to the external palm part so that the metacarpophalangeal joint (4) can swing in a direction perpendicular to the finger flexion direction.

8. The dexterous finger according to claim 1, characterized in that: The number of tendon ropes is two, and the remote driver (5) comprises: a control circuit board (52), and two driving servos (51) mounted and connected to the control circuit board (52), the two driving servos (51) each pulling and connecting a tendon rope, and the control circuit board (52) gives an angle control instruction to the driving servos (51) through a PWM signal, thereby controlling the flexion and extension of the finger through the tendon rope.

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