Seven degrees of freedom dexterous hand

Abstract

The application discloses a seven-degree-of-freedom dexterous hand, which comprises a palm, fingers and a thumb, four fingers and a thumb are arranged on the palm, the four fingers are installed at a first end of the palm, a flip rudder and a rotary rudder are arranged at a second end of the palm, the thumb is connected with the flip rudder through a flip support, the rotary rudder is connected with a rotary disc through a rotary pull rod to drive the rotary disc to rotate on the palm, the flip rudder is connected with the rotary disc, the same power unit is arranged on the fingers and the thumb, the power unit comprises a motor, a screw rod and a nut which is sleeved on the screw rod, the motor drives the screw rod to rotate through a gear set to make the nut perform linear displacement to drive the knuckle bending of the fingers or the thumb, the bending movement of the four fingers, the bending movement of the thumb, the flip and rotary movement of the thumb constitute seven active degrees of freedom. The seven-degree-of-freedom dexterous hand has the advantages of high movement precision, good durability and low processing cost.

Description

Technical Field

[0001] This invention relates to the field of robotic arm technology, and more particularly to a seven-degree-of-freedom dexterous hand. Background Technology

[0002] Dexterous hands, as the core component of humanoid robotic arms, are widely used in industrial and service robots, but they struggle to simultaneously meet the demands for multiple degrees of freedom, long lifespan, and low cost. As the degrees of freedom increase, the cost further rises. Summary of the Invention

[0003] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0004] The equipment is expensive and has a short lifespan.

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, embodiments of the present invention propose a seven-degree-of-freedom dexterous hand, including a palm, fingers, and a thumb. The palm has four fingers and a thumb. The four fingers are mounted on the first end of the palm, and a flip servo and a rotation servo are arranged on the second end of the palm. The thumb is connected to the flip servo via a flip bracket. The rotation servo is connected to a rotating disk via a rotating rod to drive the rotating disk to rotate on the palm. The flip servo is connected to the rotating disk. Identical power units are provided on the fingers and the thumb. The power unit includes a motor, a screw, and a nut sleeved on the screw. The motor drives the screw to rotate via a gear set so that the nut performs linear displacement to drive the knuckles of the fingers or the thumb to bend. The bending motion of the four fingers, the bending motion of the thumb, the flipping motion of the thumb, and the rotational motion of the thumb constitute seven active degrees of freedom.

[0007] The present invention has the advantages and technical effects of high motion accuracy, good durability, and low processing cost. The screw and nut cooperation improves motion accuracy and durability, the small range of thumb movement is driven by a servo motor to reduce costs, and the overall structure is simplified to reduce costs.

[0008] In some embodiments, the output shaft of the motor is parallel to the screw, and the gear set includes an output gear arranged on the output shaft of the motor and an input gear fixed on the screw. The output gear meshes with the input gear to drive the screw to rotate about its own axis.

[0009] In some embodiments, the finger includes a fingertip, a knuckle, and a first support. The power unit is located in the cavity of the first support. The first support is pivotally connected to a first end of the knuckle, and a second end of the knuckle is pivotally connected to the fingertip. A nut of the power unit is connected to the knuckle via a pull rod. The knuckle is also connected to the fingertip via a first connecting rod. The linear displacement of the nut drives the knuckle to rotate about a pivot point with respect to the first support via the pull rod.

[0010] In some embodiments, an arcuate groove is provided on the knuckle, and the end of the pull rod away from the nut is connected to the arcuate groove and can slide along the arcuate groove. A pivot is provided at the pivot connection between the knuckle and the fingertip, and a torsion spring is sleeved on the pivot. The two ends of the torsion spring abut against the knuckle and the fingertip, respectively. When the finger is in a straight state and is impacted by an external force, the pull rod slides along the arcuate groove to allow the knuckle to be passively bent toward the palm side. After the external force disappears, the torsion spring releases elastic potential energy to drive the knuckle and the fingertip back to the straight state.

[0011] In some embodiments, the thumb includes a thumb support and a thumb tip, the power unit is disposed in the cavity of the thumb support, the thumb support is pivotally connected to the flip support, the thumb tip is connected to the nut of the power unit via a second pull rod, the thumb tip is connected to the thumb support via a thumb connecting rod, and the linear displacement of the nut of the power unit causes the thumb tip to bend via the thumb pull rod.

[0012] In some embodiments, an arcuate groove is provided on the tip of the thumb, and the end of the thumb lever away from the nut is embedded in the arcuate groove and can slide along the arcuate groove.

[0013] In some embodiments, a tension spring is also included, one end of which is fixedly connected to the flipping bracket and the other end of which is fixedly connected to the thumb bracket. When the thumb is struck by an external force, the thumb lever slides along the arc groove to allow the thumb tip to bend passively. After the external force disappears, the tension spring pulls the thumb bracket to rotate around the pivot point with the flipping bracket to realize the reset of the thumb tip.

[0014] In some embodiments, the flip servo is arranged on the palm side of the hand, and the output shaft of the flip servo is parallel to the palm plane. The rotation servo is arranged on the back side of the hand, and the axis of the rotation servo is perpendicular to the palm plane. One end of the rotation rod is connected to the output shaft of the rotation servo, and the other end of the rotation rod is connected to a non-center position of the rotating disk.

[0015] In some embodiments, the first end of the screw is adjacent to the palm, the second end of the screw is adjacent to the knuckle or the tip of the thumb, the pitch of the screw decreases from the first end to the second end, the screw includes a large pitch section and a small pitch section, the large pitch section is adjacent to the first end side, the small pitch section is adjacent to the second end side, the nut drives the fingers to close at high speed when the large pitch section moves, and the nut drives the fingers to provide a large thrust for grasping when the small pitch section moves.

[0016] In some embodiments, the first end of the screw is adjacent to the palm, the second end of the screw is adjacent to the knuckle or the tip of the thumb, and the pitch of the screw gradually decreases from the first end to the second end, and the pitch of the screw decreases continuously and smoothly.

[0017] This application has the following advantages: The parallel arrangement of the motor output shaft and screw creates a compact structure, reducing installation space and ensuring stable and precise power transmission. A built-in chamber in the power unit provides protection. Arc grooves on the knuckles allow for sliding engagement with the pull rod, and torsion spring-loaded pivots at the knuckle and fingertip pivots provide passive bending protection when the finger is subjected to external force; the torsion springs reset the finger after the force disappears, reducing costs. The thumb also features a built-in chamber to protect the power unit, resulting in a compact structure. Arc grooves on the thumb tip allow for passive bending, preventing damage to the power unit. A tension spring between the flip bracket and the thumb bracket enables the thumb to reset after passive bending under external force, reducing costs and providing a fast reset response. The flip and rotation servos are located on the palm side and back of the hand, respectively, fully utilizing the three-dimensional space of the palm and avoiding component interference. The screw has large and small pitch sections, enabling high-speed closing during no-load operation and high-thrust gripping after contact, improving gripping response efficiency. The screw pitch decreases smoothly and continuously, eliminating the jamming and stress concentration caused by sudden pitch changes, allowing the fingers / thumb to smoothly transition from high-speed closing to high-thrust gripping, resulting in a smooth gripping experience. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the palm side of the hand of a seven-degree-of-freedom dexterous hand according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the palmar dorsal side of the hand of a seven-degree-of-freedom dexterous hand according to an embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of the structure of the fingers of a seven-degree-of-freedom dexterous hand according to an embodiment of the present invention.

[0021] Figure 4 This is a schematic diagram of a partial cross-sectional structure of the fingers of a seven-degree-of-freedom dexterous hand according to an embodiment of the present invention.

[0022] Figure 5This is a schematic diagram of the structure of the thumb of a seven-degree-of-freedom dexterous hand according to an embodiment of the present invention.

[0023] Reference numerals: 1. Palm; 2. Finger; 3. Thumb; 4. Flip bracket; 5. Flip servo; 6. Tension spring; 7. Rotation servo; 8. Rotation lever; 9. Knuckle; 10. Fingertip; 11. First bracket; 12. Power unit; 13. Lever; 14. Output gear; 15. Input gear; 16. Motor; 17. Screw; 18. Nut; 19. Rotating disk; 20. First connecting rod; 21. Torsion spring; 22. Thumb fingertip; 23. Thumb connecting rod; 24. Thumb bracket. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0025] An embodiment of the present invention proposes a seven-degree-of-freedom dexterous hand, including a palm 1, fingers 2, and a thumb 3. The palm 1 is provided with four fingers 2 and a thumb 3. The four fingers 2 are installed at the first end of the palm 1. The second end of the palm 1 is provided with a flip servo 5 and a rotation servo 7. The thumb 3 is connected to the flip servo 5 through a flip bracket 4. The rotation servo 7 is connected to a rotating disk 19 through a rotating rod 8 to drive the rotating disk 19 to rotate on the palm 1. The flip servo 5 is connected to the rotating disk 19. The fingers 2 and the thumb 3 are provided with the same power unit 12. The power unit 12 includes a motor 16, a screw 17, and a nut 18 sleeved on the screw 17. The motor 16 drives the screw 17 to rotate through a gear set so that the nut 18 performs linear displacement to drive the knuckle 9 of the fingers 2 or the thumb 3 to bend. The bending motion of the four fingers 2, the bending motion of the thumb 3, the flipping motion of the thumb 3, and the rotational motion of the thumb 3 constitute seven active degrees of freedom.

[0026] The seven-DOF dexterous hand uses the palm 1 as its support base. The four fingers 2 are concentrated at the first end of the palm 1 to form a coordinated grasp, improving the coordination of the grasping operation. A flip servo 5 and a rotation servo 7 are located at the second end of the palm 1. The thumb 3 is arranged separately from the fingers 2 to avoid component interference. The thumb 3 is connected to the flip servo 5 via a flip bracket 4. The flip servo 5 drives the flip bracket 4, causing the thumb 3 to flip. The rotation servo 7 is connected to a rotating disk 19 via a rotating rod 8. The rod 13 pulls the rotating disk 19 to rotate on the palm 1, thereby driving the flip servo 5 and the thumb 3 mounted on the disk to complete their rotational movements. The fingers 2 and thumb 3 use the same power unit 12, eliminating the need for separate drive components for the fingers 2 and thumb 3, reducing the types of parts and manufacturing costs, and making later maintenance and replacement more convenient. The power unit 12 consists of a motor 16, a screw 17, and a nut 18. The motor 16 drives the screw 17 to rotate via a gear set, converting the rotational motion of the motor 16 into the linear displacement of the nut 18. This linear displacement of the nut 18 then drives the flexion of the knuckle 9 of the finger 2 or thumb 3. Compared to direct drive by a servo motor, the transmission method of the screw 17 and nut 18 provides greater output force, higher transmission precision, and less wear during operation, thus improving the movement accuracy and lifespan of the dexterous hand. The independent flexing motion of the four fingers 2, combined with the bending, flipping, and rotating motions of the thumb 3, constitutes seven active degrees of freedom. These multiple degrees of freedom allow the dexterous hand to perform more complex grasping, pinching, and other fine operations, enhancing its applicability and operational flexibility.

[0027] In some embodiments, the output shaft of the motor 16 is parallel to the screw 17, and the gear set includes an output gear 14 arranged on the output shaft of the motor 16 and an input gear 15 fixed on the screw 17. The output gear 14 meshes with the input gear 15 to drive the screw 17 to rotate about its own axis.

[0028] Specifically, the output shaft of motor 16 is arranged parallel to screw 17, making the overall structure of power unit 12 more compact and reducing the installation space of power unit 12 within the first bracket 11 and thumb bracket 24, thus meeting miniaturization requirements. The parallel axes ensure smoother gear meshing and reduce off-center loading and wear during transmission. The fixed connection between the gears and the output shaft and screw 17 minimizes backlash during transmission, improving the rotational accuracy of screw 17, ensuring accurate linear displacement of nut 18, and allowing for more precise bending movements of finger 2 and thumb 3. Output gear 14 and input gear 15 can be helical gears. Helical gear meshing involves surface contact, resulting in smoother meshing, lower noise, and the ability to withstand greater loads.

[0029] In some embodiments, the finger 2 includes a fingertip 10, a knuckle 9, and a first support 11. The power unit 12 is located in the cavity of the first support 11. The first support 11 is pivotally connected to the first end of the knuckle 9, and the second end of the knuckle 9 is pivotally connected to the fingertip 10. The nut 18 of the power unit 12 is connected to the knuckle 9 through a pull rod 13. The knuckle 9 is also connected to the fingertip 10 through a first connecting rod 20. The linear displacement of the nut 18 drives the knuckle 9 to rotate around the pivot point with the first support 11 through the pull rod 13.

[0030] Specifically, the power unit 12 is built into the cavity of the first support 11, providing protection against external impacts and dust affecting operation, making the finger 2 structure more compact and reducing space occupation. The first support 11 and the first end of the knuckle 9, and the second end of the knuckle 9 and the fingertip 10 are all pivotally connected. Together with the first connecting rod 20 between the knuckle 9 and the fingertip 10, a multi-segment linkage transmission structure is formed, making the bending movement of the finger 2 more in line with the movement trajectory of the human finger 2, improving the grip fit and flexibility. The nut 18 of the power unit 12 is connected to the knuckle 9 through the pull rod 13, converting the linear displacement of the nut 18 into the rotational movement of the knuckle 9 around the pivot point of the first support 11, reducing power loss in the power transmission process, improving the response speed and movement accuracy of the bending movement of the finger 2, and the pivotal connection makes the movement of the finger 2 smoother.

[0031] In some embodiments, an arc groove is provided on the knuckle 9, and the end of the pull rod 13 away from the nut 18 is connected to the arc groove and can slide along the arc groove. A pivot is provided at the pivot connection between the knuckle 9 and the fingertip 10, and a torsion spring 21 is sleeved on the pivot. The two ends of the torsion spring 21 abut against the knuckle 9 and the fingertip 10 respectively. When the finger 2 is in a straight state and is hit by an external force, the pull rod 13 slides along the arc groove to allow the knuckle 9 to be passively bent towards the palm side. After the external force disappears, the torsion spring 21 releases elastic potential energy to drive the knuckle 9 and the fingertip 10 to return to the straight state.

[0032] Specifically, the arc groove on the knuckle 9 slides into the end of the pull rod 13, allowing the pull rod 13 to slide along the arc groove when the finger 2 is impacted by an external force, while simultaneously driving the knuckle 9 to actively bend with the linear displacement of the nut 18. This provides space for the passive bending of the knuckle 9, preventing the external force from being directly transmitted to the power unit 12 and causing damage to the transmission components or motor 16, thus protecting the power unit 12. A torsion spring 21 is fitted on the pivot shaft at the pivot connection between the knuckle 9 and the fingertip 10. The two ends of the torsion spring 21 abut against the knuckle 9 and the fingertip 10 respectively. The torsion spring 21 is in a pre-tensioned state, releasing elastic potential energy after the external force disappears to drive the knuckle 9 and the fingertip 10 back to the straight state. No additional control mechanism or reset mechanism is required, reducing control costs. The response speed is fast, enabling timely response to sudden external force impacts. The structure is simple, the failure rate is low, and the stability of the finger 2 is improved. The passive bending direction of the knuckle 9 towards the palm side avoids interference with the palm 1 or other fingers 2 during passive bending. Optionally, a roller is provided at the end of the pull rod 13 that contacts the arc groove. The roller converts sliding friction into rolling friction, reducing friction loss and making the sliding of the pull rod 13 smoother.

[0033] In some embodiments, the thumb 3 includes a thumb support 24 and a thumb tip 22. The power unit 12 is arranged in the cavity of the thumb support 24. The thumb support 24 is pivotally connected to the flip support 4. The thumb tip 22 is connected to the nut 18 of the power unit 12 through a second pull rod 13. The thumb tip 22 is connected to the thumb support 24 through a thumb connecting rod 23. The linear displacement of the nut 18 of the power unit 12 causes the thumb tip 22 to bend through the thumb pull rod 13.

[0034] Specifically, the power unit 12 is arranged within the thumb support 24 cavity, providing protection for the power unit 12 and isolating it from external dust and impacts, making the thumb 3 structure more compact and reducing its overall size. The thumb support 24 and the flip support 4 are pivotally connected, allowing the thumb 3 to perform a flipping motion in conjunction with the flip support 4 while completing its own bending action, thus increasing the thumb 3's degree of freedom. The thumb tip 22 is connected to the nut 18 of the power unit 12 via the second pull rod 13, and simultaneously connected to the thumb support 24 via the thumb connecting rod 23, forming a linkage transmission structure. This structure stably converts the linear displacement of the nut 18 into the bending action of the thumb tip 22, ensuring the bending response speed and motion accuracy of the thumb 3. The structure is similar to that of the finger 2, reducing processing and assembly costs and making subsequent maintenance and component replacement more convenient. Optionally, a flexible buffer layer can be provided at the contact end of the thumb tip 22. When grasping fragile or smooth objects, this increases contact friction, improves grasping stability, and acts as a buffer to prevent damage to objects, expanding the applicable range of dexterity hand grasping. The flexible buffer layer can be silicone or rubber pads.

[0035] In some embodiments, an arc groove is provided on the thumb tip 22, and the end of the thumb lever 13 away from the nut 18 is embedded in the arc groove and can slide along the arc groove.

[0036] Specifically, an arc groove is provided on the thumb tip 22 and forms a sliding fit with the end of the thumb pull rod 13, so that the thumb pull rod 13 actively bends the thumb tip 22 when transmitting the linear displacement of the nut 18, and slides freely along the arc groove when the thumb 3 is impacted by an external force, providing a margin for the passive bending of the thumb tip 22, avoiding the external force from being directly transmitted to the power unit 12 in the thumb support 24 through the pull rod 13, preventing the transmission components such as the motor 16 and screw 17 of the power unit 12 from deforming or being damaged due to rigid stress, and protecting the power unit 12.

[0037] In some embodiments, a tension spring 6 is also included. One end of the tension spring 6 is fixedly connected to the flipping bracket 4, and the other end of the tension spring 6 is fixedly connected to the thumb bracket 24. When the thumb 3 is impacted by an external force, the thumb pull rod 13 slides along the arc groove to allow the thumb tip 22 to be passively bent. After the external force disappears, the tension spring 6 pulls the thumb bracket 24 to rotate around the pivot point with the flipping bracket 4 to realize the reset of the thumb tip 22.

[0038] Specifically, the tension spring 6 maintains a pre-tensioned state, providing continuous tension for the reset of the thumb 3. When the thumb 3 is impacted by an external force, causing the thumb lever 13 to slide along the arc groove and the thumb tip 22 to bend passively, the tension spring 6 is further stretched and stores elastic potential energy as the thumb support 24 rotates. After the external force disappears, the tension spring 6 releases the elastic potential energy to pull the thumb support 24 to rotate in the opposite direction around the pivot point of the flipping support 4, thereby driving the thumb tip 22 to reset precisely. No additional electronic control components are required, reducing control costs. The reset response speed is fast, and the initial position of the thumb 3 can be restored in time. The tension spring 6 has a simple structure, occupies little space, and will not interfere with other transmission components.

[0039] In some embodiments, the flip servo 5 is arranged on the palm side of the hand 1, and the output shaft of the flip servo 5 is parallel to the plane of the hand 1. The rotation servo 7 is arranged on the back side of the hand 1, and the axis of the rotation servo 7 is perpendicular to the plane of the hand 1. One end of the rotation rod 8 is connected to the output shaft of the rotation servo 7, and the other end of the rotation rod 8 is connected to the non-center position of the rotating disk 19.

[0040] Specifically, the flip servo 5 and the rotation servo 7 are arranged in an upper and lower partitioned manner on the back and palm of the hand, making full use of the three-dimensional space of the palm 1 and avoiding structural interference between the two servos in the same plane. The driving force for the flip and rotation of the thumb 3 is output along the direction parallel to and perpendicular to the palm 1, respectively, so that the two motion dimensions of the thumb 3 are independent of each other, avoiding the action deviation caused by motion linkage and improving the accuracy of the flip and rotation of the thumb 3. The output shaft of the flip servo 5 is parallel to the plane of the palm 1, so that the flipping motion of the thumb 3 is more in line with the operating plane of the palm 1, and in conjunction with the grasping action trajectory of the dexterous hand. The axis of the rotation servo 7 is perpendicular to the plane of the palm 1, so that the motion of the rotating lever 8 is converted into the planar rotation of the rotating disk 19, reducing the loss of power transmission. One end of the rotating lever 8 is connected to the output shaft of the rotation servo 7, and the other end is connected to the non-center position of the rotating disk 19. The principle of eccentric transmission can be used to convert the small-angle rotation of the rotation servo 7 into the rotation of the rotating disk 19, improving the transmission efficiency.

[0041] In another feasible structure, a transmission rod is rotatably connected to the center of the rotating disk 19. The two ends of the transmission rod are connected to the center of the rotating disk 19 and the rotating pull rod 8, respectively. As the rotating pull rod 8 moves, it drives the transmission rod to move, causing the rotating disk 19 to rotate. One end of the transmission rod is fixedly connected to the center of the rotating disk 19, and the other end is rotatably connected to the rotating pull rod 8 via a pivot. The lever arm design of the transmission rod enables the conversion of small-angle movements of the rotary servo 7 into effective rotation of the rotating disk 19, ensuring the transmission efficiency of the thumb 3's rotation.

[0042] In some embodiments, the first end of the screw 17 is adjacent to the palm 1, and the second end of the screw 17 is adjacent to the knuckle 9 or the tip 22 of the thumb. The pitch of the screw 17 decreases from the first end to the second end. The screw 17 includes a large pitch section and a small pitch section. The large pitch section is adjacent to the first end side, and the small pitch section is adjacent to the second end side. When the nut 18 moves in the large pitch section, it drives the finger 2 to close at high speed. When the nut 18 moves in the small pitch section, it drives the finger 2 to provide a large thrust for grasping.

[0043] Specifically, the screw 17 efficiently transmits the linear displacement of the nut 18 to the knuckle 9 or the thumb tip 22, ensuring transmission efficiency. The screw 17's pitch decreases from the first end to the second end, dividing it into a large pitch segment and a small pitch segment. At a constant speed of the motor 16, the nut 18 achieves a faster linear displacement speed when moving in the large pitch segment, driving the finger 2 or thumb 3 to achieve high-speed closure during the no-load phase, improving the grasping response efficiency of the dexterous hand and reducing the time consumption of no-load movement. When the nut 18 moves to the small pitch segment, the output thrust of the screw 17 increases with the decrease in pitch, providing a greater grasping thrust for the finger 2 or thumb 3, meeting the load requirements for tightly gripping after contact with the object, adapting to grasping operations. The variable pitch structure eliminates the need for additional structures, achieving the high-speed no-load to high-thrust grasping motion switching through the screw 17's own structure, reducing manufacturing costs. The segmentation of the large pitch segment and the small pitch segment makes the pitch transition more reasonable, preventing the nut 18 from getting stuck at the pitch change point and ensuring smooth movement.

[0044] A smooth transition pitch section can be set at the junction of the large pitch section and the small pitch section, so that the nut 18 can smoothly slide from the large pitch section into the small pitch section, reducing the frictional resistance and component wear caused by sudden pitch changes.

[0045] In another embodiment, the first end of the screw 17 is adjacent to the palm 1, and the second end of the screw 17 is adjacent to the knuckle 9 or the tip of the thumb 22. The pitch of the screw 17 gradually decreases from the first end to the second end, and the pitch of the screw 17 decreases continuously and smoothly.

[0046] Specifically, the pitch of screw 17 decreases continuously and smoothly from the first end to the second end. Compared with a segmented pitch design, this eliminates the fit clearance and stress concentration problems at the abrupt pitch changes. The nut 18 slides smoothly and without jamming throughout its entire movement on screw 17, reducing frictional losses between screw 17 and nut 18. With motor 16 maintaining a constant speed, as nut 18 moves from the first end to the second end of screw 17, the pitch decreases continuously and smoothly, achieving a smooth decrease in linear motion speed and a continuous linear increase in output thrust. This allows the movement of fingers 2 and thumb 3 to seamlessly and smoothly transition from the high-speed closing motion in the no-load stage to the large-force grasping motion after contact with the object, improving the overall smoothness of the dexterous hand's grasping operation. It also allows the grasping force to gradually increase with the contact process with the object, avoiding damage to smooth, fragile, or other easily damaged objects due to a sudden increase in thrust. The continuous pitch structure can be integrally molded, reducing processing costs.

[0047] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" 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 this invention and simplifying the description, and are not intended to 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 this invention.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0049] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0050] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0051] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0052] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A seven-DOF dexterous hand, characterized in that, include: A hand (1), fingers (2), and thumb (3) are provided. The hand (1) has four fingers (2) and a thumb (3). The four fingers (2) are installed at the first end of the hand (1). The second end of the hand (1) is provided with a flip servo (5) and a rotation servo (7). The thumb (3) is connected to the flip servo (5) through a flip bracket (4). The rotation servo (7) is connected to a rotating disk (19) through a rotating pull rod (8) to drive the rotating disk (19) to rotate on the hand (1). The flip servo (5) and the rotating disk (19) are connected to each other. Connected, the same power unit (12) is provided on the finger (2) and the thumb (3). The power unit (12) includes a motor (16), a screw (17) and a nut (18) sleeved on the screw (17). The motor (16) drives the screw (17) to rotate through a gear set so that the nut (18) performs linear displacement to drive the knuckle (9) of the finger (2) or the thumb (3) to bend. The bending movement of the four fingers (2), the bending movement of the thumb (3), and the flipping and rotational movement of the thumb (3) constitute seven active degrees of freedom.

2. The seven-DOF dexterous hand according to claim 1, characterized in that, The output shaft of the motor (16) is parallel to the screw (17). The gear set includes an output gear (14) arranged on the output shaft of the motor (16) and an input gear (15) fixed on the screw (17). The output gear (14) meshes with the input gear (15) to drive the screw (17) to rotate around its own axis.

3. The seven-DOF dexterous hand according to claim 1, characterized in that, The finger (2) includes a fingertip (10), a knuckle (9), and a first support (11). The power unit (12) is located in the cavity of the first support (11). The first support (11) is pivotally connected to the first end of the knuckle (9). The second end of the knuckle (9) is pivotally connected to the fingertip (10). The nut (18) of the power unit (12) is connected to the knuckle (9) through a pull rod (13). The knuckle (9) is also connected to the fingertip (10) through a first connecting rod (20). The linear displacement of the nut (18) drives the knuckle (9) to rotate around the pivot point with respect to the first support (11) through the pull rod (13).

4. The seven-DOF dexterous hand according to claim 3, characterized in that, The knuckle (9) is provided with an arc groove. The end of the pull rod (13) away from the nut (18) is connected to the arc groove and can slide along the arc groove. A pivot is provided at the pivot connection between the knuckle (9) and the fingertip (10). A torsion spring (21) is sleeved on the pivot. The two ends of the torsion spring (21) abut against the knuckle (9) and the fingertip (10) respectively. When the finger (2) is in a straight state and is hit by an external force, the pull rod (13) slides along the arc groove to allow the knuckle (9) to be passively bent towards the palm side. After the external force disappears, the torsion spring (21) releases elastic potential energy to drive the knuckle (9) and the fingertip (10) to return to the straight state.

5. The seven-DOF dexterous hand according to claim 1, characterized in that, The thumb (3) includes a thumb support (24) and a thumb tip (22). The power unit (12) is arranged in the cavity of the thumb support (24). The thumb support (24) is pivotally connected to the flip support (4). The thumb tip (22) is connected to the nut (18) of the power unit (12) through a second pull rod (13). The thumb tip (22) is connected to the thumb support (24) through a thumb connecting rod (23). The linear displacement of the nut (18) of the power unit (12) drives the thumb tip (22) to bend through the thumb pull rod (13).

6. The seven-DOF dexterous hand according to claim 5, characterized in that, A circular groove is provided on the tip (22) of the thumb, and the end of the thumb lever (13) away from the nut (18) is embedded in the circular groove and can slide along the circular groove.

7. The seven-DOF dexterous hand according to claim 6, characterized in that, It also includes a tension spring (6), one end of which is fixedly connected to the flipping bracket (4), and the other end of which is fixedly connected to the thumb bracket (24). When the thumb (3) is struck by an external force, the thumb pull rod (13) slides along the arc groove to allow the thumb tip (22) to be passively bent. After the external force disappears, the tension spring (6) pulls the thumb bracket (24) to rotate around the pivot point with the flipping bracket (4) to realize the reset of the thumb tip (22).

8. The seven-DOF dexterous hand according to claim 1, characterized in that, The flip servo (5) is arranged on the palm side of the hand (1), and the output shaft of the flip servo (5) is parallel to the plane of the hand (1). The rotation servo (7) is arranged on the back side of the hand (1), and the axis of the rotation servo (7) is perpendicular to the plane of the hand (1). One end of the rotation rod (8) is connected to the output shaft of the rotation servo (7), and the other end of the rotation rod (8) is connected to the non-center position of the rotating disk (19).

9. The seven-DOF dexterous hand according to claim 1, characterized in that, The first end of the screw (17) is adjacent to the palm (1), and the second end of the screw (17) is adjacent to the knuckle (9) or the tip of the thumb (22). The pitch of the screw (17) decreases from the first end to the second end. The screw (17) includes a large pitch section and a small pitch section. The large pitch section is adjacent to the first end side, and the small pitch section is adjacent to the second end side. When the large pitch section moves, the nut (18) drives the finger (2) to close at high speed. When the small pitch section moves, the nut (18) drives the finger (2) to provide a large thrust for grasping.

10. The seven-DOF dexterous hand according to claim 1, characterized in that, The first end of the screw (17) is adjacent to the palm (1), and the second end of the screw (17) is adjacent to the knuckle (9) or the tip of the thumb (22). The pitch of the screw (17) gradually decreases from the first end to the second end, and the pitch of the screw (17) decreases continuously and smoothly.

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