A rigid-flexible coupled dexterous hand

Abstract

The application discloses a kind of rigid-flexible coupling dexterous hand, including palm base and multiple finger units;Each finger unit includes a finger base, a fingertip module and multiple knuckles, the finger base is fixedly installed on the palm base;The fingertip module includes fingertip, tendon, fingertip base and fingertip fixing frame, the tendon and fingertip are made of flexible elastic material, the fingertip is installed on fingertip fixing frame, and the tendon is used to connect the fingertip fixing frame and fingertip base;For any one finger unit, each knuckle thereof includes knuckle bracket and a knuckle servo motor fixedly installed on knuckle bracket, and a finger base servo motor is also fixedly installed on the finger base;In order from the finger base to the fingertip, the finger base servo motor is used to control the movement of the first knuckle, the last knuckle servo motor is used to control the movement of the fingertip base, and the other knuckle servo motors are used to control the movement of the next knuckle.

Description

Technical Field

[0001] This invention relates to the field of dexterity technology, and in particular to a rigid-flexible coupled dexterity hand. Background Technology

[0002] As an important end effector for humanoid robots, dexterous hands, compared to traditional robotic hands that can only perform specific tasks, have the advantages of high flexibility and versatility. They can endow robots with more precise manipulation capabilities and stronger environmental adaptability, and are an important way to promote humanoid robots towards general artificial intelligence. At present, research on dexterous hands mainly focuses on dexterous hands made of rigid materials and soft dexterous hands made of artificial muscles.

[0003] Dexterous hands made of rigid materials often employ cable-driven mechanisms. These hands typically use a motor as the drive unit, with gear or pulley transmissions working in conjunction with the motor to drive the cable, thereby controlling the various joints and enabling complex, high-precision motion control. While dexterous hands made of rigid materials offer advantages such as high energy conversion efficiency and good force control, their rigid structure poses safety hazards when manipulating fragile objects and engaging in human-machine interaction, making them unsuitable for everyday tasks.

[0004] Soft dexterous hands composed of artificial muscles are often gas-driven. Gas actuation controls the opening and closing force and speed of the fingers by adjusting air pressure, offering advantages such as fast response speed and simple structure. Although soft dexterous hands composed of artificial muscles have the characteristics of convenient energy storage, good compliance, and high safety, their dynamic control performance is relatively poor.

[0005] Therefore, there is an urgent need to design a rigid-flexible coupled dexterous hand that can balance dynamic control performance and safety performance in order to improve its adaptability to a wider range of application scenarios and more complex tasks. Summary of the Invention

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A dexterous hand with rigid-flexible coupling, comprising a palm base and multiple finger units;

[0008] Each finger unit includes a finger base, a fingertip module, and multiple phalanges, with the finger base fixedly mounted on the palm base;

[0009] The fingertip module includes a fingertip, a tendon, a fingertip base, and a fingertip fixing frame. The tendon and fingertip are made of a soft, elastic material. The fingertip is mounted on the fingertip fixing frame, and the tendon is used to connect the fingertip fixing frame and the fingertip base.

[0010] For any finger unit, each phalanx includes a phalanx support and a phalanx servo fixedly mounted on the phalanx support, and a finger base servo is also fixedly mounted on the base of the finger.

[0011] In sequence from the base of the finger to the fingertip, the base of the finger servo controls the movement of the first phalanx, the last phalanx servo controls the movement of the fingertip base, and the other phalanx servos control the movement of the next phalanx.

[0012] In some embodiments, for any finger unit, the plurality of phalanges include a first phalange, a second phalange and a third phalange, the first phalange including a first phalange servo and a first phalange bracket, the second phalange including a second phalange servo and a second phalange bracket, and the third phalange including a third phalange servo and a third phalange bracket.

[0013] In some embodiments, the number of finger units is five, including one thumb unit and four ordinary finger units with the same structure.

[0014] In some embodiments, for the thumb unit, the finger base servo is used to control the flexion and extension movement of the first phalanx, the first phalanx servo is used to control the rotational movement of the second phalanx, the second phalanx servo is used to control the flexion and extension movement of the third phalanx, and the third phalanx servo is used to control the flexion and extension movement of the fingertip base.

[0015] In some embodiments, for the thumb unit, the output shafts of the finger base servo, the second knuckle servo, and the third knuckle servo are all perpendicular to the direction when the thumb unit is extended, and the output shaft of the first knuckle servo is all in the same direction when the thumb unit is extended.

[0016] Furthermore, the output shaft of the finger base servo is fixedly connected to the bottom side of the first phalanx support, the output shaft of the second phalanx servo is fixedly connected to the bottom side of the third phalanx support, and the output shaft of the third phalanx servo is fixedly connected to the bottom side of the fingertip base, thereby realizing the control of flexion and extension movements;

[0017] The output shaft of the first knuckle servo is fixedly connected to the bottom surface of the second knuckle bracket, thereby realizing the control of rotary motion.

[0018] In some embodiments, for any ordinary finger unit, the finger base servo is used to control the flexion and extension movement of the first phalanx, the first phalanx servo is used to control the lateral movement of the second phalanx, the second phalanx servo is used to control the flexion and extension movement of the third phalanx, and the third phalanx servo is used to control the flexion and extension movement of the fingertip base.

[0019] In some embodiments, for any ordinary finger unit, the direction of the output shaft of the finger base servo is consistent with the direction when the ordinary finger unit is straight, and the directions of the output shafts of the first knuckle servo, the second knuckle servo, and the third knuckle servo are all perpendicular to the direction when the ordinary finger unit is straight.

[0020] The output shaft of the servo motor at the base of the finger is fixedly connected to a first bevel gear, and the bottom end of the first phalanx bracket is fixedly connected to a second bevel gear. The first bevel gear and the second bevel gear mesh with each other and the included angle between them is 90 degrees, thereby transmitting the motion of the servo motor output shaft to the first phalanx to control the flexion and extension motion of the first phalanx.

[0021] The output shaft of the first knuckle servo is fixedly connected to the middle of the side of the second knuckle bracket to control the lateral swing motion of the second knuckle;

[0022] The output shaft of the second phalanx servo is fixedly connected to the bottom side of the third phalanx bracket to control the flexion and extension movement of the third phalanx;

[0023] The output shaft of the third phalanx servo is fixedly connected to the bottom side of the fingertip base to control the flexion and extension movement of the fingertip base.

[0024] In some embodiments, a plurality of palm base servos are also installed on the palm base, and the plurality of palm base servos correspond one-to-one with a plurality of finger units;

[0025] Each palm-based servo motor is equipped with a steel wire, and a winding wheel is fixedly installed on the output shaft of the palm-based servo motor;

[0026] One end of the steel wire is wound around the winding wheel, and the other end is fixedly connected to the side of the fingertip fixing frame facing the palm base;

[0027] The hand-based servo motor is used to control the bending of the tendon via a steel wire.

[0028] Compared with existing technologies, the beneficial effects of the rigid-flexible coupling dexterous hand provided by this invention are as follows: Addressing the technical shortcomings of existing dexterous hands in balancing dynamic control performance and safety performance, this invention employs a unique design in its rigid-flexible coupling method, combining rigid knuckles with flexible fingertips and tendons, effectively balancing dynamic control performance and safety performance. This results in a dexterous hand with better compliance and higher safety performance compared to dexterous hands based on rigid materials, and higher control precision and better dynamic control performance compared to soft dexterous hands based on artificial muscles. Attached Figure Description

[0029] Figure 1 A schematic diagram of the rigid-flexible coupled dexterous hand provided by the present invention;

[0030] Figure 2 This is a schematic diagram of a typical finger unit;

[0031] Figure 3 This is a schematic diagram of the thumb finger unit;

[0032] Figure 4 A schematic diagram of the hand-based servo motor and related structures;

[0033] Figure 5 This is a schematic diagram of the connection point between two knuckles.

[0034] Explanation of icon numbers:

[0035] 1. First knuckle; 11. First knuckle support; 12. First knuckle servo; 13. Second bevel gear; 2. Second knuckle; 21. Second knuckle support; 22. Second knuckle servo; 23. Output shaft; 24. Hex bolt; 3. Third knuckle; 31. Third knuckle support; 32. Third knuckle servo; 4. Palm base; 41. Palm base servo; 42. Steel wire; 43. Winding reel; 5. Finger base servo; 51. First bevel gear; 6. Fingertip; 7. Tendon; 8. Fingertip base; 9. Fingertip retainer; 10. Ordinary finger unit; 20. Thumb unit. Detailed Implementation

[0036] To make the technical means, creative features, objectives and effects of this invention easier to understand, the following detailed embodiments further illustrate how this invention is implemented.

[0037] Reference Figure 1 and Figure 2 As shown in one specific embodiment, the present invention provides a rigid-flexible coupled dexterous hand, including a palm base 4 and multiple finger units; each finger unit includes a finger base, a fingertip module and multiple phalanges, the finger base is fixedly mounted on the palm base 4; the fingertip module includes a fingertip 6, a tendon 7, a fingertip base 8 and a fingertip fixing frame 9, the tendon 7 and the fingertip 6 are made of a flexible elastic material, the fingertip 6 is mounted on the fingertip fixing frame 9, and the tendon 7 is used to connect the fingertip fixing frame 9 and the fingertip base 8; for any finger unit, each phalanx includes a phalanx support and a phalanx servo fixedly mounted on the phalanx support, and a finger base servo 5 is also fixedly mounted on the finger base; in the order from the finger base to the fingertip 6, the finger base servo 5 is used to control the movement of the first phalanx, the last phalanx servo is used to control the movement of the fingertip base 8, and the other phalanx servos are used to control the movement of the next phalanx.

[0038] Additionally, refer to Figure 2As shown, the two ends of the tendon 7 can be connected to the fingertip base 8 and fingertip fixation frame 9 on the upper and lower sides through straight grooves. The fingertip 6 can be glued to the fingertip fixation frame 9, thus realizing the coupling of rigid and flexible mechanisms. The tendon 7 and fingertip 6 are made of soft elastic material, such as silicone casting; the rigid mechanisms such as the fingertip base 8 and knuckle support can be made using 3D printing technology.

[0039] Preferably, for any finger unit, the multiple phalanges include a first phalange 1, a second phalange 2, and a third phalange 3. The first phalange 1 includes a first phalange servo 12 and a first phalange support 11. The second phalange 2 includes a second phalange servo 22 and a second phalange support 21. The third phalange 3 includes a third phalange servo 32 and a third phalange support 31.

[0040] Preferably, the number of finger units is five, including one thumb unit 20 and four ordinary finger units 10 with the same structure.

[0041] Further reference Figure 3 As shown, for the thumb unit 20, the finger base servo 5 is used to control the flexion and extension movement of the first phalanx 1, the first phalanx servo 12 is used to control the rotation movement of the second phalanx 2, the second phalanx servo 22 is used to control the flexion and extension movement of the third phalanx 3, and the third phalanx servo 32 is used to control the flexion and extension movement of the fingertip base 8.

[0042] Specifically, for the thumb unit 20, the output shafts of the finger base servo 5, the second knuckle servo 22, and the third knuckle servo 32 are all perpendicular to the direction when the thumb unit 20 is extended, and the output shaft of the first knuckle servo 12 is consistent with the direction when the thumb unit 20 is extended. Furthermore, the output shaft of the finger base servo 5 is fixedly connected to the bottom side of the first knuckle support 11, the output shaft of the second knuckle servo 22 is fixedly connected to the bottom side of the third knuckle support 31, and the output shaft of the third knuckle servo 32 is fixedly connected to the bottom side of the fingertip base 8, thereby realizing the control of flexion and extension movements; the output shaft of the first knuckle servo 12 is fixedly connected to the bottom surface of the second knuckle support 21, thereby realizing the control of rotational movements.

[0043] Reference Figure 2 As shown, for any ordinary finger unit 10, the finger base servo 5 is used to control the flexion and extension movement of the first phalanx 1, the first phalanx servo 12 is used to control the lateral movement of the second phalanx 2, the second phalanx servo 22 is used to control the flexion and extension movement of the third phalanx 3, and the third phalanx servo 32 is used to control the flexion and extension movement of the fingertip base 8.

[0044] Specifically, for any ordinary finger unit 10, the direction of the output shaft of the finger base servo 5 is consistent with the direction when the ordinary finger unit 10 is straight, and the directions of the output shafts of the first knuckle servo 12, the second knuckle servo 22, and the third knuckle servo 32 are all perpendicular to the direction when the ordinary finger unit 10 is straight; the output shaft of the finger base servo 5 is fixedly connected to a first bevel gear 51, and the bottom end of the first knuckle support 11 is fixedly connected to a second bevel gear 13, the first bevel gear 51 and the second bevel gear 13 meshing with each other and The angle between the two is 90 degrees, thereby transmitting the motion of the servo output shaft to the first phalanx 1 to control the flexion and extension of the first phalanx 1; the output shaft of the first phalanx servo 12 is fixedly connected to the middle side of the second phalanx bracket 21 to control the lateral swing of the second phalanx 2; the output shaft of the second phalanx servo 22 is fixedly connected to the bottom side of the third phalanx bracket 31 to control the flexion and extension of the third phalanx 3; the output shaft of the third phalanx servo 32 is fixedly connected to the bottom side of the fingertip base 8 to control the flexion and extension of the fingertip base 8.

[0045] It is evident that the transmission design of this rigid-flexible coupled dexterous hand references the structure and function of the human hand, employing two different transmission design methods for the thumb and other fingers. Because the thumb is located on the front side of the other four fingers and possesses the ability to oppose itself, it can perform opposing movements (approaching or moving away from one or more other fingers). Therefore, the thumb occupies a crucial position among all parts of the human hand.

[0046] In this embodiment, the thumb unit 20's palm-opposing ability is achieved by the coordinated work of the thumb unit 20's rotational degree of freedom and the remaining flexion and extension degrees of freedom. Multiple flexion and extension degrees of freedom work together to achieve the thumb's bending function, while the rotational degree of freedom is achieved by the second phalanx 2 rotating around the output shaft of the first phalanx servo motor 12, realizing a function similar to the joints in the human hand, expanding the range of motion of the thumb unit 20, and enabling the thumb unit 20 to complete palm-opposing and palm-resisting movements.

[0047] For the ordinary finger unit 10, in order to improve structural compactness, the finger base servo 5 and the first phalanx support 11 are connected by two bevel gears, thereby realizing the motion transmission of flexion and extension degrees of freedom within a limited space. Multiple flexion and extension degrees of freedom work together to achieve the function of finger bending; while the lateral swing degree of freedom is realized by the rotation of the second phalanx 2 around the output shaft of the first phalanx servo 12, realizing the lateral swing motion of the finger on the horizontal plane, thus making the movement of the dexterous hand fingers more flexible, and at the same time increasing the redundancy of the dexterous hand's degrees of freedom.

[0048] Based on the analysis of human hand structure and finger function, this rigid-flexible coupled dexterous hand was designed with two different finger transmission methods, enabling the dexterous hand to complete both palm-opposing and palm-fighting movements.

[0049] Further reference Figure 4 As shown, preferably, a plurality of palm base servos 41 are also installed on the palm base 4, and the plurality of palm base servos 41 correspond one-to-one with a plurality of finger units; each palm base servo 41 is equipped with a steel wire 42, and a winding wheel 43 is fixedly installed on the output shaft of the palm base servo 41; one end of the steel wire 42 is wound on the winding wheel 43, and the other end is fixedly connected to the side of the fingertip fixing frame 9 facing the palm base 4; the palm base servo 41 is used to control the bending of the tendon 7 through the steel wire 42.

[0050] Furthermore, the steel wire 42 can pass through a pre-set hole on the fingertip base 8 and then be fixedly connected to the fingertip fixing frame 9 to limit the range of motion of the steel wire 42. The output shaft of the hand base servo motor 41 drives the winding wheel 43 to rotate forward or backward, controlling the stretching motion of the steel wire 42. When the steel wire 42 pulls the tendon 7, it causes the tendon 7 to bend under force; when the tension of the steel wire 42 on the tendon 7 decreases, the tendon 7 returns to its original position under its own elastic force. In this way, reliable control of the fingertip bending freedom is achieved, meeting the design requirements of compliance and safety performance for this dexterous hand.

[0051] As can be seen, in this embodiment, each finger is equipped with five servo motors: a palm base servo motor 41, a finger base servo motor 5, and three knuckle servo motors. That is, each finger has five degrees of freedom, so that the rigid-flexible coupled dexterous hand exhibits kinematic characteristics and configuration similar to the human hand, achieving the purpose of dexterous movement.

[0052] Furthermore, considering the requirements of the dexterous hand for control precision and dynamic performance, this rigid-flexible coupled dexterous hand adopts a simple, integrated drive design. The servo motor can be an HTS-20L type. (Refer to...) Figure 5 As shown, when a servo motor is connected to its driving structure, taking the second knuckle servo motor 22 and the third knuckle support 31 of the thumb unit 20 as an example, the lower end of the third knuckle support 31 has a threaded hole. A hexagonal bolt 24 is used to fix the third knuckle support 31 to the output shaft 23 of the second knuckle servo motor 22, thereby transmitting the rotation of the output shaft 23 to the third knuckle support 31. In this way, the offset angle of each knuckle on the control surface can be precisely controlled, achieving simple and efficient motion transmission between different knuckle levels, thus enabling the dexterous hand's palm-on-palm capability. Except for special cases (such as the finger base servo motor 5 of the ordinary finger unit 10 being connected to the first knuckle support 11 via two bevel gears), most servos and their driving structures can achieve motion transmission in a similar manner.

[0053] The hardware control system of this rigid-flexible coupled dexterous hand can consist of a control module, a communication module, an I / O module, a power supply module, a sensor module, and a host computer. The control module can use an STM32F103 microcontroller; the sensor module can include multiple visual and tactile sensors, respectively positioned at different locations on the dexterous hand. The control module connects to each servo and sensor via serial communication and is physically connected to the host computer via USB, using serial communication to send the current motion status of each servo to the host computer and simultaneously receive control commands from the host computer, achieving closed-loop control of the dexterous hand. The I / O module can send control commands from the remote controller to the control module, enabling human-machine interaction functionality of the dexterous hand.

[0054] In summary, the rigid-flexible coupled dexterous hand provided by this invention addresses the technical shortcomings of existing dexterous hands in balancing dynamic control performance and safety performance. It employs a unique design in its rigid-flexible coupling method, combining rigid knuckles with flexible fingertips 6 and tendons 7, effectively balancing dynamic control performance and safety performance. This results in a dexterous hand with better compliance and higher safety performance compared to dexterous hands based on rigid materials, and higher control precision and better dynamic control performance compared to soft dexterous hands based on artificial muscles.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A dexterous hand with rigid-flexible coupling, characterized in that, Includes a palm base (4) and multiple finger units; Each finger unit includes a finger base, a fingertip module and multiple phalanges, with the finger base fixedly mounted on the palm base (4); The fingertip module includes a fingertip (6), a tendon (7), a fingertip base (8), and a fingertip fixing frame (9). The tendon (7) and the fingertip (6) are made of a soft elastic material. The fingertip (6) is mounted on the fingertip fixing frame (9). The tendon (7) is used to connect the fingertip fixing frame (9) and the fingertip base (8). For any finger unit, each phalanx includes a phalanx support and a phalanx servo fixedly mounted on the phalanx support, and a finger base servo is also fixedly mounted on the base of the finger (5). In the order from the base of the finger to the fingertip (6), the base of the finger servo (5) is used to control the movement of the first phalanx, the last phalanx servo is used to control the movement of the fingertip base (8), and the other phalanx servos are used to control the movement of the next phalanx. For any finger unit, multiple phalanges include a first phalanx (1), a second phalanx (2), and a third phalanx (3). The first phalanx (1) includes a first phalanx servo (12) and a first phalanx support (11). The second phalanx (2) includes a second phalanx servo (22) and a second phalanx support (21). The third phalanx (3) includes a third phalanx servo (32) and a third phalanx support (31). The number of finger units is five, including one thumb unit (20) and four ordinary finger units (10) with the same structure. For the thumb unit (20), the finger base servo (5) is used to control the flexion and extension movement of the first phalanx (1), the first phalanx servo (12) is used to control the rotation movement of the second phalanx (2), the second phalanx servo (22) is used to control the flexion and extension movement of the third phalanx (3), and the third phalanx servo (32) is used to control the flexion and extension movement of the fingertip base (8); For the thumb unit (20), the output shafts of the finger base servo (5), the second knuckle servo (22) and the third knuckle servo (32) are all perpendicular to the direction when the thumb unit (20) is extended, and the output shaft of the first knuckle servo (12) is in the same direction as the direction when the thumb unit (20) is extended. Furthermore, the output shaft of the finger base servo (5) is fixedly connected to the bottom side of the first knuckle support (11), the output shaft of the second knuckle servo (22) is fixedly connected to the bottom side of the third knuckle support (31), and the output shaft of the third knuckle servo (32) is fixedly connected to the bottom side of the fingertip base (8), thereby realizing the control of flexion and extension movements; The output shaft of the first knuckle servo motor (12) is fixedly connected to the bottom surface of the second knuckle bracket (21), thereby realizing the control of rotary motion.

2. The rigid-flexible coupled dexterous hand according to claim 1, characterized in that, For any ordinary finger unit (10), the finger base servo (5) is used to control the flexion and extension movement of the first phalanx (1), the first phalanx servo (12) is used to control the lateral movement of the second phalanx (2), the second phalanx servo (22) is used to control the flexion and extension movement of the third phalanx (3), and the third phalanx servo (32) is used to control the flexion and extension movement of the fingertip base (8).

3. The rigid-flexible coupled dexterous hand according to claim 2, characterized in that, For any ordinary finger unit (10), the direction of the output shaft of the finger base servo (5) is consistent with the direction when the ordinary finger unit (10) is straight, and the directions of the output shafts of the first knuckle servo (12), the second knuckle servo (22) and the third knuckle servo (32) are all perpendicular to the direction when the ordinary finger unit (10) is straight. The output shaft of the finger base servo (5) is fixedly connected to a first bevel gear (51), and the bottom end of the first phalanx bracket (11) is fixedly connected to a second bevel gear (13). The first bevel gear (51) and the second bevel gear (13) mesh with each other and the included angle between them is 90 degrees, thereby transmitting the motion of the servo output shaft to the first phalanx (1) to control the flexion and extension motion of the first phalanx (1). The output shaft of the first knuckle servo (12) is fixedly connected to the middle of the side of the second knuckle bracket (21) to control the lateral swing motion of the second knuckle (2); The output shaft of the second phalanx servo (22) is fixedly connected to the bottom side of the third phalanx bracket (31) to control the flexion and extension movement of the third phalanx (3); The output shaft of the third knuckle servo motor (32) is fixedly connected to the bottom side of the fingertip base (8) to control the flexion and extension movement of the fingertip base (8).

4. The rigid-flexible coupled dexterous hand according to claim 1, characterized in that, The palm base (4) is also equipped with multiple palm base servo motors (41), and the multiple palm base servo motors (41) correspond one-to-one with multiple finger units; Each palm-based servo motor (41) is equipped with a steel wire (42), and a winding wheel (43) is fixedly installed on the output shaft of the palm-based servo motor (41). One end of the steel wire (42) is wound on the winding wheel (43), and the other end is fixedly connected to the side of the fingertip fixing bracket (9) facing the palm base (4); The hand base servo (41) is used to control the bending of the tendon (7) via a steel wire (42).

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