A fully direct-drive dexterous hand and a control method thereof

Abstract

The present application relates to a kind of full direct-drive dexterous hand and its control method.The present application includes palm;Four finger module, be arranged as four groups and be installed in palm, each group of four finger module includes swing base and multiple movable joints connected to swing base in turn, multiple movable joints include four finger metacarpophalangeal joint and four finger distal interphalangeal joint connected in turn, or four finger metacarpophalangeal joint, four finger proximal interphalangeal joint, four finger distal interphalangeal joint connected in turn;Swing module, including swing direct-drive motor, tumbler, rotating shaft and bearing;Thumb module, installed in palm, thumb module includes rotating base, base support, thumb metacarpophalangeal joint, thumb distal interphalangeal joint and first thumb direct-drive motor, second thumb direct-drive motor and third thumb direct-drive motor.The present application omits tendon and multistage connecting rod transmission, with the advantages of short transmission chain, compact structure, high reliability, assembly and maintenance is convenient and initiative freedom is more.

Description

Technical Field

[0001] This invention relates to the field of robotics, and in particular to a fully direct-drive dexterous hand and its control method. Background Technology

[0002] The dexterous hand is the core actuator of an integrated robot, combining gripping functionality with human-hand-like maneuvering capabilities. In addition to basic grasping actions, some models also integrate tactile sensors, cameras, and other sensing elements to assist in motion control and status feedback.

[0003] In terms of driving methods, dexterous hands generally use motor drives, which convert the rotational or linear motion of the motor into the bending and swinging of the fingers through a transmission mechanism. Based on the motor output form, they are mainly divided into two categories: linear output and rotary output; the corresponding transmission schemes are mainly linkage transmission and chordal transmission. Linear output motors are often paired with linkage mechanisms, using the linkage to achieve finger bending and multi-link differential to achieve lateral swinging; rotary output motors are mostly used with chordal transmission, using the chords to pull and drive joint movement, and some designs directly integrate the motor into the finger's rotational joint. The control panel is usually integrated inside the palm or at the wrist.

[0004] However, the use of tendon ropes, connecting rods, and multi-stage reduction gears increases the length of the transmission chain, the number of parts, and the workload of assembly and adjustment. Tendon ropes are also prone to elongation, wear, and tension changes, while connecting rod mechanisms suffer from accumulated clearances and large space requirements. Therefore, in practical applications, dexterous hands still face prominent problems such as low reliability, complex assembly processes, insufficient service life, and difficult maintenance, which restrict their large-scale deployment and long-term stable operation. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problems of long transmission chains, complex structures, difficult assembly and maintenance, and insufficient reliability of dexterous hands in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides a fully direct-drive dexterous hand, comprising: palm; The four-finger module is set into four groups and installed on the palm. Each group of the four-finger module includes a swing base and multiple movable joints connected to the swing base in sequence. The multiple movable joints include four metacarpophalangeal joints and four distal interphalangeal joints connected in sequence, or four metacarpophalangeal joints, four proximal interphalangeal joints and four distal interphalangeal joints connected in sequence. The swing module is configured corresponding to the four-finger module. The swing module includes a swing direct drive motor mounted on the palm, a shift fork connected to the output shaft of the swing direct drive motor, a rotating shaft connected to the swing base, and a bearing disposed between the swing base and the palm. The rotating shaft is inserted into the sliding groove of the shift fork so that the shift fork pushes the rotating shaft and drives the swing base to swing around the center line of the bearing. A thumb module is installed on the palm of the hand. The thumb module includes a rotating base, a base support, a thumb metacarpophalangeal joint, a thumb distal interphalangeal joint, and a first thumb direct drive motor, a second thumb direct drive motor, and a third thumb direct drive motor. The first thumb direct drive motor is installed on the palm of the hand, and its output shaft is connected to the rotating base. The rotating base is connected to the base support to drive the thumb module to swing. The output shafts of the second and third thumb direct drive motors are connected to the rotating joints of the thumb metacarpophalangeal joint and the thumb distal interphalangeal joint, respectively.

[0007] In one embodiment of the present invention, the plurality of movable joints includes four metacarpophalangeal joints, four proximal interphalangeal joints, four distal interphalangeal joints, and a first four-finger direct drive motor, a second four-finger direct drive motor, and a third four-finger direct drive motor correspondingly mounted on the swing base, the four metacarpophalangeal joints, and the four proximal interphalangeal joints. The output shafts of the first four-finger direct drive motor, the second four-finger direct drive motor, and the third four-finger direct drive motor are respectively connected to the four metacarpophalangeal joints, the four proximal interphalangeal joints, and the four distal interphalangeal joints. The output shaft axes of the first four-finger direct drive motor, the second four-finger direct drive motor, and the third four-finger direct drive motor are parallel to each other, and the rotation centers of the three direct drive motors are located on the same straight line along the finger extension direction.

[0008] In one embodiment of the present invention, the plurality of movable joints includes four-finger metacarpophalangeal joints, four-finger distal interphalangeal joints, and a first four-finger direct drive motor and a third four-finger direct drive motor correspondingly mounted on the swing base and the four-finger metacarpophalangeal joints. The output shafts of the first four-finger direct drive motor and the third four-finger direct drive motor are respectively connected to the four-finger metacarpophalangeal joints and the four-finger distal interphalangeal joints. The output shaft axes of the first four-finger direct drive motor and the third four-finger direct drive motor are parallel to each other, and the rotation centers of the two direct drive motors are located on the same straight line along the finger extension direction.

[0009] In one embodiment of the present invention, the root of the distal interphalangeal joint of the four fingers and the top of the metacarpophalangeal joint of the four fingers abut against each other when the fingers are extended, and the root of the metacarpophalangeal joint of the four fingers and the top of the swing base abut against each other when the fingers are extended, so as to form a mechanical limit. Alternatively, the base of the distal interphalangeal joint of the four fingers abuts against the top of the proximal interphalangeal joint of the four fingers when the fingers are extended, the base of the proximal interphalangeal joint of the four fingers abuts against the top of the metacarpophalangeal joint of the four fingers when the fingers are extended, and the base of the metacarpophalangeal joint of the four fingers abuts against the top of the swing base when the fingers are extended, so as to form a mechanical limit.

[0010] In one embodiment of the present invention, it further includes: The wrist, which connects to the palm; The first fingertip sensor and the second fingertip sensor are respectively disposed at the ends of the distal interphalangeal joints of the four fingers and the distal interphalangeal joint of the thumb; The electronic control assembly includes a control board disposed at the wrist and a wiring harness, wherein the control board is electrically connected to each direct drive motor and the fingertip sensor via the wiring harness.

[0011] In one embodiment of the present invention, a first wiring groove is provided at the top of the distal interphalangeal joints of the four fingers, the proximal interphalangeal joints of the four fingers, and the metacarpophalangeal joints of the four fingers, and the motor control wire in the wire bundle passes through the first wiring groove. The thumb metacarpophalangeal joint and the distal interphalangeal joint of the thumb are both provided with a second wiring groove. The base bracket and the rotating base are both provided with a wiring notch communicating with the second wiring groove. The wire bundle passes through the second wiring groove and the wiring notch in sequence and is connected to the control board.

[0012] In one embodiment of the present invention, the rotating shaft has a threaded section that is threadedly connected to the swing base, and the outer diameter of the sliding mating shaft section of the rotating shaft located in the sliding groove is smaller than the groove width of the sliding groove; the shift fork is connected to the output shaft of the swing direct drive motor by a screw so that when the swing base swings, the rotating shaft slides relative to the shift fork along the sliding groove.

[0013] In one embodiment of the present invention, the swing direct drive motor is fixed to the palm of the hand by a mounting position and a motor fixing plate, and the swing base is rotatably mounted to the palm of the hand by two bearings.

[0014] In one embodiment of the present invention, the rotation center lines of the output shafts of the second thumb direct drive motor and the third thumb direct drive motor are parallel to the extension direction of the thumb when it is extended; the thumb metacarpophalangeal joint and the distal interphalangeal joint of the thumb abut against each other when the thumb is straightened to form a mechanical limit.

[0015] The present invention also provides a control method for a fully direct-drive dexterous hand, which utilizes the aforementioned fully direct-drive dexterous hand, comprising: Obtain the target motion command of the dexterous hand, and determine the joints to be moved in the four-finger module and the thumb module and the driving state of the corresponding direct drive motor according to the target motion command; Control the rotation of the swing direct drive motor corresponding to the four-finger module to be swung, so that the swing direct drive motor drives the shift fork to rotate. The shift fork pushes the rotating shaft to move through the sliding groove, and makes the rotating shaft slide relative to the sliding groove, thereby driving the swing base to swing around the center line of the bearing to adjust the swing position of the corresponding four-finger module relative to the palm. According to the target action command, control at least one of the corresponding first four-finger direct drive motor, second four-finger direct drive motor and third four-finger direct drive motor to rotate, so that the output shaft of the corresponding direct drive motor directly drives the corresponding joints of the four-finger metacarpophalangeal joint, the four-finger proximal interphalangeal joint and the four-finger distal interphalangeal joint to rotate, so as to adjust the bending posture of the corresponding four-finger module. Control the rotation of the first thumb direct drive motor, drive the rotating base to rotate through the output shaft of the first thumb direct drive motor, and drive the base bracket and the thumb part connected to the base bracket to swing relative to the palm through the rotating base; According to the target action command, control at least one of the second thumb direct drive motor and the third thumb direct drive motor to rotate, so that the output shafts of the second thumb direct drive motor and the third thumb direct drive motor directly drive the corresponding joints of the thumb metacarpophalangeal joint and the distal interphalangeal joint of the thumb to rotate, so as to adjust the bending posture of the thumb module.

[0016] The technical solution of the present invention has the following advantages compared with the prior art: The present invention discloses a fully direct-drive dexterous hand and its control method, which uses a direct-drive motor to directly drive each finger joint, eliminating tendons, multi-links and multi-stage transmission mechanisms, shortening the transmission chain, reducing transmission gaps and vulnerable parts, and improving action responsiveness, transmission reliability and service life.

[0017] The four sets of four-finger modules of the present invention adopt an independent modular structure, which facilitates separate assembly, testing and replacement, and can reduce the difficulty of assembly and maintenance of the whole hand.

[0018] This invention can form fifteen active degrees of freedom by combining four-finger bending, four-finger swinging, thumb bending, and thumb swinging, which is highly flexible and can complete clamping, pinching, and multi-finger coordinated operation.

[0019] This invention arranges direct-drive motors at each joint and centrally positions the control board at the wrist, resulting in a compact overall structure that is similar in size to a human hand.

[0020] The fork and the pivot of the present invention slide together, which converts the rotational motion of the direct drive motor into the swinging motion of the swing base, and at the same time avoids over-constraint of the mechanism by relative sliding of the pivot, so that the swinging action is stable and reliable. Attached Figure Description

[0021] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the overall structure of the fully direct-drive dexterous hand of the present invention.

[0023] Figure 2 This is a schematic diagram of the structure of the three-bending joint four-finger module of the present invention.

[0024] Figure 3 This is a schematic diagram of the structure of the four-finger bending joint module of the present invention.

[0025] Figure 4 This is a schematic diagram of the thumb module of the present invention.

[0026] Explanation of reference numerals in the instruction manual: 1a. First fingertip sensor; 1b. Second fingertip sensor; 2. Distal interphalangeal joint of four fingers; 3. Proximal interphalangeal joint of four fingers; 4. Metacarpophalangeal joint of four fingers; 5. Swing base; 6. Bearing; 7. Shift fork; 81. First four-finger direct drive motor; 82. Second four-finger direct drive motor; 83. Third four-finger direct drive motor; 84. Swing direct drive motor; 85. First thumb direct drive motor; 86. Second thumb direct drive motor; 87. Third thumb direct drive motor; 9. Palm; 10. Wrist; 11. Control board; 12. Thumb metacarpophalangeal joint; 13. Distal interphalangeal joint of thumb; 14. Motor mounting plate; 15. Rotating shaft; 16. Base bracket; 17. Rotating base. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0028] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0029] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0030] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.

[0031] Reference Figures 1 to 4 As shown, a fully direct-drive dexterous hand includes: 9 for the palm; The four-finger module is configured into four groups and installed on the palm 9. Each group of the four-finger module includes a swing base 5 and multiple movable joints connected to the swing base 5 in sequence. The multiple movable joints include four-finger metacarpophalangeal joints 4 and four-finger distal interphalangeal joints 2 connected in sequence, or four-finger metacarpophalangeal joints 4, four-finger proximal interphalangeal joints 3, and four-finger distal interphalangeal joints 2 connected in sequence. The swing module is configured corresponding to the four-finger module. The swing module includes a swing direct drive motor 84 mounted on the palm 9, a shift fork 7 connected to the output shaft of the swing direct drive motor 84, a rotating shaft 15 connected to the swing base 5, and a bearing 6 disposed between the swing base 5 and the palm 9. The rotating shaft 15 is inserted into the sliding groove of the shift fork 7 so that the shift fork 7 pushes the rotating shaft 15 and drives the swing base 5 to swing around the center line of the bearing 6. A thumb module, installed on the palm 9, includes a rotating base 17, a base support 16, a thumb metacarpophalangeal joint 12, a distal interphalangeal joint 13 of the thumb, and a first thumb direct drive motor 85, a second thumb direct drive motor 86, and a third thumb direct drive motor 87. The first thumb direct drive motor 85 is installed on the palm 9, and its output shaft is connected to the rotating base 17. The rotating base 17 is connected to the base support 16 to drive the thumb module to swing. The output shafts of the second thumb direct drive motor 86 and the third thumb direct drive motor 87 are respectively connected to the rotating joints of the thumb metacarpophalangeal joint 12 and the distal interphalangeal joint 13 of the thumb. When the first thumb direct drive motor 85 rotates, its output shaft directly drives the rotating base 17 to rotate. The rotating base 17 further drives the base support 16 and the thumb metacarpophalangeal joint 12 and the distal interphalangeal joint 13 mounted on the base support 16 to swing as a whole, thereby changing the position and orientation of the thumb relative to the four sets of four-finger modules.

[0032] It should be noted that four sets of four-finger modules are installed side by side on the palm 9, corresponding to the positions of the index, middle, ring, and little fingers of the simulated human hand. The thumb module is located on one side of the palm 9, and the wrist 10 is connected to the lower part of the palm 9.

[0033] Reference Figure 2 As shown, the multiple movable joints include four-finger metacarpophalangeal joints 4, four-finger proximal interphalangeal joints 3, four-finger distal interphalangeal joints 2, and a first four-finger direct drive motor 81, a second four-finger direct drive motor 82, and a third four-finger direct drive motor 83 correspondingly mounted on the swing base 5, the four-finger metacarpophalangeal joints 4, and the four-finger proximal interphalangeal joints 3, thereby forming a four-finger module with three active bending degrees of freedom. The output shafts of the first four-finger direct drive motor 81, the second four-finger direct drive motor 82, and the third four-finger direct drive motor 83 are respectively connected to the four-finger metacarpophalangeal joints 4, the four-finger proximal interphalangeal joints 3, and the four-finger distal interphalangeal joints 2; the output shaft axes of the first four-finger direct drive motor 81, the second four-finger direct drive motor 82, and the third four-finger direct drive motor 83 are parallel to each other, and the rotation centers of the three direct drive motors are located on the same straight line along the finger extension direction.

[0034] The above arrangement allows the three bending joints to be arranged sequentially along the length of the fingers, making the shape of the four-finger module closer to that of a human finger. On the other hand, it helps to reduce the space occupied by each direct drive motor in the width direction of the fingers, allowing the four sets of four-finger modules to be arranged in a more compact parallel arrangement in the palm 9.

[0035] During finger flexion, the rotation of three four-finger direct-drive motors can be controlled individually, or one, two, or three four-finger direct-drive motors can be controlled to rotate simultaneously or sequentially according to the target action. For example, when grasping a large object, the metacarpophalangeal joints 4, proximal interphalangeal joints 3, and distal interphalangeal joints 2 of the four fingers can be flexed together; when making fingertip contact or making more precise posture adjustments, the position of one or two joints can be adjusted individually.

[0036] By employing a direct-drive method to achieve active movement of each finger joint, the output shaft of the corresponding direct-drive motor is directly connected to the corresponding movable joint. The rotational motion output by the direct-drive motor directly drives the corresponding joint to move around its rotation axis 15, eliminating the need for long-distance transmission mechanisms such as tendons, transmission rods, etc., between the motor and the corresponding joint. This shortens the power transmission path, reduces the number of transmission components, and helps improve the overall compactness of the dexterous hand structure, as well as the convenience of assembly and maintenance.

[0037] Furthermore, to limit the extreme positions of each joint in the direction of finger extension, the root of the distal interphalangeal joint 2 of the four fingers and the top of the metacarpophalangeal joint 4 of the four fingers abut against each other when the fingers are extended, and the root of the metacarpophalangeal joint 4 of the four fingers abut against the top of the swing base 5 when the fingers are extended, so as to form a mechanical limit.

[0038] By directly abutting between the aforementioned adjacent structural components to form a mechanical limit, the extension limit position of each bending joint can be restricted without the need for additional independent limiting parts. This simplifies the structure and prevents overextension of the joints.

[0039] Reference Figure 3 As shown, in another embodiment, depending on the different requirements for the size, weight, or finger freedom of the dexterous hand, the four-finger module can also adopt a structure with two active bending joints. The plurality of movable joints include four-finger metacarpophalangeal joints 4, four-finger distal interphalangeal joints 2, and a first four-finger direct drive motor 81 and a third four-finger direct drive motor 83 correspondingly mounted on the swing base 5 and the four-finger metacarpophalangeal joints 4. The output shafts of the first four-finger direct drive motor 81 and the third four-finger direct drive motor 83 are respectively connected to the four-finger metacarpophalangeal joints 4 and the four-finger distal interphalangeal joints 2; the output shaft axes of the first four-finger direct drive motor 81 and the third four-finger direct drive motor 83 are parallel to each other, and the rotation centers of the two direct drive motors are located on the same straight line along the finger extension direction.

[0040] In this embodiment, omitting the proximal interphalangeal joint 3 of the four fingers and the corresponding second direct drive motor 82 of the four fingers can further reduce the number of parts and axial length of the four-finger module, making it suitable for applications with high requirements for finger size or overall hand weight.

[0041] Accordingly, the base of the distal interphalangeal joint 2 of the four fingers abuts against the top of the proximal interphalangeal joint 3 of the four fingers when the fingers are extended, the base of the proximal interphalangeal joint 3 of the four fingers abuts against the top of the metacarpophalangeal joint 4 of the four fingers when the fingers are extended, and the base of the metacarpophalangeal joint 4 of the four fingers abuts against the top of the swing base 5 when the fingers are extended, so as to form a mechanical limit.

[0042] In one embodiment, refer to Figure 1 As shown, it also includes: Wrist 10, connected to palm 9; The first fingertip sensor 1a and the second fingertip sensor 1b are respectively disposed at the ends of the distal interphalangeal joints 2 of the four fingers and the distal interphalangeal joint 13 of the thumb; the second fingertip sensor 1b is used to detect the contact state between the end of the thumb and the target object.

[0043] The electronic control assembly includes a control board 11 disposed at the wrist 10 and a wiring harness, wherein the control board 11 is electrically connected to each direct drive motor and the fingertip sensor via the wiring harness.

[0044] The control board 11 is located at the wrist 10 to reduce the space occupied by the control elements in the palm 9 and to facilitate the centralized connection of the wires of the direct drive motors and fingertip sensors.

[0045] In addition, the palm 9 has a reserved swing space inside for the four-finger modules to swing laterally. The palm 9 has a groove on the thumb side to accommodate the thumb's extension and movement during swinging. The lower end of the palm 9 is connected to the wrist 10, and the control plate 11 is located at the wrist 10, thereby reducing the space occupied by the control plate 11 on the swinging space inside the palm.

[0046] In one embodiment, in order to reduce the exposure of wires during finger movement and interference between wires and adjacent structures, a first wiring groove is provided at the top of the distal interphalangeal joint 2 of the four fingers, the proximal interphalangeal joint 3 of the four fingers, and the metacarpophalangeal joint 4 of the four fingers, and the motor control wire in the wire bundle passes through the first wiring groove. The thumb metacarpophalangeal joint 12 and the distal interphalangeal joint 13 of the thumb are both provided with a second wiring groove. The base bracket 16 and the rotating base 17 are both provided with a wiring notch communicating with the second wiring groove. The wire bundle passes through the second wiring groove and the wiring notch in sequence and is connected to the control board 11.

[0047] By setting continuous or corresponding wiring spaces in each joint, base bracket 16 and rotating base 17, the wire bundle can be arranged along the internal or surface-defined area of ​​the dexterous hand's own structure, reducing the impact of the wires on the movement of each joint, and facilitating modular assembly and subsequent maintenance.

[0048] In one embodiment, a portion of the rotating shaft 15 is configured as a threaded segment that connects to a corresponding threaded hole on the swing base 5, thereby keeping the rotating shaft 15 fixed to the swing base 5.

[0049] Another part of the rotating shaft 15 forms a sliding fit shaft section, which is inserted into the sliding groove of the shift fork 7. The outer diameter of the sliding fit shaft section is smaller than the width of the sliding groove, so that the rotating shaft 15 can be pushed by the groove wall of the sliding groove and can move relative to the shift fork 7 along the sliding groove.

[0050] Bearings 6 are provided on both sides or at the top and bottom ends of the swing base 5. In one specific installation method, two bearings 6 are provided on the swing base 5, and the bearings 6 are interference-fitted with the swing base 5. The bearings 6 also mate with the corresponding bearings 6 on the palm 9, thereby rotatably mounting the swing base 5 on the palm 9.

[0051] The center lines of the two bearings 6 together define the swing axis of the swing base 5. When it is necessary to drive the corresponding four-finger module to swing laterally, the control board 11 controls the swing direct drive motor 84 to rotate. The output shaft of the swing direct drive motor 84 drives the shift fork 7 to rotate around the output shaft axis.

[0052] During the rotation of the shift fork 7, the groove wall of the sliding groove contacts the rotating shaft 15 and applies a pushing force to the rotating shaft 15. Since the rotating shaft 15 is fixed to the swing base 5, and the swing base 5 is mounted on the palm 9 through the bearing 6, the pushing force on the rotating shaft 15 is converted into the rotation of the swing base 5 around the center line of the bearing 6.

[0053] Meanwhile, since the rotation trajectory of the shift fork 7 is not exactly the same as the movement trajectory of the rotating shaft 15 with the swing base 5, the rotating shaft 15 can slide relative to the shift fork 7 along the sliding groove during the process of the shift fork 7 pushing the rotating shaft 15.

[0054] Thus, through the sliding engagement between the shift fork 7 and the rotating shaft 15, the rotational motion of the swing direct drive motor 84 is converted into the swing of the swing base 5 around the center line of the bearing 6, thereby realizing the lateral position adjustment of the entire four-finger module.

[0055] The power transmission components in this structure mainly include the shift fork 7 and the rotating shaft 15. The structure is relatively simple. At the same time, the rotating shaft 15 and the sliding groove retain relative sliding freedom, which can adapt to the change in the relative position of the transmission point relative to the swing base 5 during the rotation of the shift fork 7.

[0056] In one embodiment, refer to Figure 1 As shown, the swing direct drive motor 84 is fixed to the palm 9 via the mounting position and the motor fixing plate 14, and the swing base 5 is rotatably mounted to the palm 9 via two bearings 6.

[0057] In one embodiment, refer to Figure 4 As shown, the rotation center lines of the output shafts of the second thumb direct drive motor 86 and the third thumb direct drive motor 87 are parallel to the extension direction of the thumb when it is extended; the thumb metacarpophalangeal joint 12 and the distal interphalangeal joint 13 of the thumb abut against each other when the thumb is extended to form a mechanical limit to restrict the distal interphalangeal joint 13 of the thumb from continuing to rotate in the extension direction.

[0058] Based on the above-described direct-drive dexterous hand structure, this embodiment also provides a control method for the direct-drive dexterous hand, including: The control board 11 first acquires the target motion command sent by the robot's upper control system or the robotic arm control system, and determines the four-finger module, thumb module, and corresponding direct drive motors that need to move based on the target motion command. The target motion command can correspond to a predetermined posture of the dexterous hand, or it can correspond to the target movement state of multiple finger joints. The control board 11 controls the corresponding direct drive motors to move according to the target motion command; when the target motion requires changing the position of a four-finger module relative to adjacent fingers, it executes four-finger swing control.

[0059] Specifically, the control board 11 controls the corresponding swing direct drive motor 84 to rotate, and the output shaft of the swing direct drive motor 84 drives the shift fork 7 to rotate. The sliding groove of the shift fork 7 pushes the rotating shaft 15 inserted therein through the groove wall, so that the rotating shaft 15 drives the swing base 5 to rotate around the center line of the bearing 6.

[0060] During the rotation of the swing base 5, the rotating shaft 15 moves relative to the shift fork 7 along the sliding groove, thereby adapting to the change in the motion trajectory between the shift fork 7 and the swing base 5.

[0061] By controlling the rotation of the swing direct drive motor 84, the lateral swing position of the corresponding four-finger module can be adjusted.

[0062] When the target action requires changing the bending posture of the four-finger module, the four-finger bending control is executed.

[0063] For a four-finger module with three active bending joints, the control board 11 controls the rotation of at least one of the first four-finger direct drive motor 81, the second four-finger direct drive motor 82 and the third four-finger direct drive motor 83 according to the target motion command.

[0064] The first four-finger direct drive motor 81 directly drives the metacarpophalangeal joint 4 of the four fingers, the second four-finger direct drive motor 82 directly drives the proximal interphalangeal joint 3 of the four fingers, and the third four-finger direct drive motor 83 directly drives the distal interphalangeal joint 2 of the four fingers.

[0065] By adjusting the position of the corresponding joints with three direct-drive motors, a single four-finger module can form bending postures of different degrees and combinations.

[0066] For a four-finger module with two active bending joints, the first four-finger direct drive motor 81 and the third four-finger direct drive motor 83 control the rotation of the metacarpophalangeal joint 4 and the distal interphalangeal joint 2 of the four fingers, respectively.

[0067] When the target action requires adjusting the position of the thumb relative to the four-finger module, thumb swing control is executed.

[0068] The control board 11 controls the rotation of the first thumb direct drive motor 85. The output shaft of the first thumb direct drive motor 85 directly drives the rotating base 17 to rotate, and the rotating base 17 drives the base support 16, the thumb metacarpophalangeal joint 12, and the distal interphalangeal joint 13 of the thumb to swing as a whole, so that the thumb moves to a position that is adapted to the current target action.

[0069] When it is necessary to adjust the thumb's flexion posture, execute thumb flexion control.

[0070] The control board 11 controls the rotation of at least one of the second thumb direct drive motor 86 and the third thumb direct drive motor 87 according to the target action command. The output shaft of the second thumb direct drive motor 86 directly drives the thumb metacarpophalangeal joint 12 to rotate, and the output shaft of the third thumb direct drive motor 87 directly drives the distal interphalangeal joint 13 of the thumb to rotate.

[0071] Through the coordinated action of the first thumb direct drive motor 85, the second thumb direct drive motor 86 and the third thumb direct drive motor 87, the overall swing position of the thumb and the posture of the two thumb bending joints can be adjusted simultaneously.

[0072] The control board 11 coordinates the movements of the four groups of four-finger modules and the thumb module according to the target action command, so that each finger forms the corresponding target posture.

[0073] For example, when performing a grasping action, the four-finger module and the thumb module can be swung according to the position of the target object so that each finger matches the target object in space; then the bending joints of each four finger and the bending joint of the thumb can be gradually bent so that the fingertips where the first fingertip sensor 1a and the second fingertip sensor 1b are located approach the target object.

[0074] The first fingertip sensor 1a and the second fingertip sensor 1b can collect contact information at the corresponding fingertip positions and send the detection signal to the control board 11, thereby providing detection information for judging the movement state of the dexterous hand.

[0075] It should be noted that this embodiment mainly illustrates the structural relationships and basic control processes between the direct drive motors, finger joints, and fingertip sensors. The specific control algorithm for further adjusting the motor angle, torque, or clamping force based on the detection results of the first fingertip sensor 1a and the second fingertip sensor 1b can be set according to the actual application scenario of the robot, and this embodiment does not limit this.

[0076] When the present invention is in operation, the bending motion of each four-finger module is directly driven by the corresponding four-finger direct drive motor, and the lateral swing of each four-finger module is realized by the corresponding swing direct drive motor 84 through the shift fork 7, the rotating shaft 15 and the swing base 5.

[0077] The thumb module achieves overall swing through the first thumb direct drive motor 85, and achieves bending of the two thumb joints through the second thumb direct drive motor 86 and the third thumb direct drive motor 87 respectively.

[0078] Thus, each of the four-finger modules and the thumb module can form relatively independent degrees of freedom of active movement.

[0079] Compared to structures that use tendons or multi-stage linkages to transmit driving force, this invention allows multiple bending joints to be directly connected to the output shafts of corresponding direct-drive motors, shortening the power transmission path between the motor and the joints and reducing intermediate transmission parts. The four sets of four-finger modules adopt the same or essentially the same modular structure and can be installed on the palm 9 respectively, facilitating assembly by dexterous hands and maintenance of individual finger modules.

[0080] Meanwhile, in addition to having multiple degrees of freedom in bending, the four-finger module can also swing relative to the palm 9 via the swing module; the thumb module can also swing as a whole via the rotating base 17, thus improving the ability of the dexterous hand to adjust the relative position of each finger in space.

[0081] This structure allows the dexterous hand to achieve multiple active degrees of freedom while maintaining an overall size similar to the human hand, while also ensuring structural compactness, transmission reliability, and modular assembly performance. When a single finger malfunctions, the corresponding four-finger module can be maintained independently without disassembling the entire hand. Direct-drive motors are positioned at the joints, reducing intermediate transmission components and maintaining a compact overall shape, making it suitable as a small end effector for embodied robots, humanoid robots, or robotic arms.

[0082] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, 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 fully direct-drive dexterous hand, characterized in that, include: Palm (9); The four-finger module is configured into four groups and installed on the palm (9). Each group of the four-finger module includes a swing base (5) and multiple movable joints connected to the swing base (5) in sequence. The multiple movable joints include the four-finger metacarpophalangeal joints (4) and the four-finger distal interphalangeal joints (2) connected in sequence, or the four-finger metacarpophalangeal joints (4), the four-finger proximal interphalangeal joints (3), and the four-finger distal interphalangeal joints (2) connected in sequence. The swing module is configured in correspondence with the four-finger module. The swing module includes a swing direct drive motor (84) mounted on the palm (9), a shift fork (7) connected to the output shaft of the swing direct drive motor (84), a rotating shaft (15) connected to the swing base (5), and a bearing (6) disposed between the swing base (5) and the palm (9). The rotating shaft (15) is inserted into the sliding groove of the shift fork (7) so that the shift fork (7) pushes the rotating shaft (15) and drives the swing base (5) to swing around the center line of the bearing (6). A thumb module is installed on the palm (9). The thumb module includes a rotating base (17), a base bracket (16), a thumb metacarpophalangeal joint (12), a distal interphalangeal joint of the thumb (13), a first thumb direct drive motor (85), a second thumb direct drive motor (86), and a third thumb direct drive motor (87). The first thumb direct drive motor (85) is installed on the palm (9), and its output shaft is connected to the rotating base (17). The rotating base (17) is connected to the base bracket (16) to drive the thumb module to swing. The output shafts of the second thumb direct drive motor (86) and the third thumb direct drive motor (87) are connected to the rotating joints of the thumb metacarpophalangeal joint (12) and the distal interphalangeal joint of the thumb (13).

2. The fully direct-drive dexterous hand according to claim 1, characterized in that, The plurality of movable joints include four-finger metacarpophalangeal joints (4), four-finger proximal interphalangeal joints (3), four-finger distal interphalangeal joints (2), and a first four-finger direct drive motor (81), a second four-finger direct drive motor (82), and a third four-finger direct drive motor (83) correspondingly installed on the swing base (5), the four-finger metacarpophalangeal joints (4), and the four-finger proximal interphalangeal joints (3). The output shafts of the first four-finger direct drive motor (81), the second four-finger direct drive motor (82), and the third four-finger direct drive motor (83) are respectively connected to the four-finger metacarpophalangeal joints (4), the four-finger proximal interphalangeal joints (3), and the four-finger distal interphalangeal joints (2). The output shaft axes of the first four-finger direct drive motor (81), the second four-finger direct drive motor (82), and the third four-finger direct drive motor (83) are parallel to each other, and the rotation centers of the three direct drive motors are located on the same straight line along the finger extension direction.

3. A fully direct-drive dexterous hand according to claim 2, characterized in that, The plurality of movable joints include four-finger metacarpophalangeal joints (4), four-finger distal interphalangeal joints (2), and a first four-finger direct drive motor (81) and a third four-finger direct drive motor (83) respectively installed on the swing base (5) and the four-finger metacarpophalangeal joints (4). The output shafts of the first four-finger direct drive motor (81) and the third four-finger direct drive motor (83) are respectively connected to the four-finger metacarpophalangeal joints (4) and the four-finger distal interphalangeal joints (2). The output shaft axes of the first four-finger direct drive motor (81) and the third four-finger direct drive motor (83) are parallel to each other, and the rotation centers of the two direct drive motors are located on the same straight line along the finger extension direction.

4. A fully direct-drive dexterous hand according to claim 1, characterized in that, The root of the distal interphalangeal joint (2) of the four fingers and the top of the metacarpophalangeal joint (4) of the four fingers abut against each other when the fingers are extended, and the root of the metacarpophalangeal joint (4) and the top of the swing base (5) abut against each other when the fingers are extended to form a mechanical limit. Alternatively, the base of the distal interphalangeal joint (2) of the four fingers abuts against the top of the proximal interphalangeal joint (3) of the four fingers when the fingers are extended, the base of the proximal interphalangeal joint (3) of the four fingers abuts against the top of the metacarpophalangeal joint (4) of the four fingers when the fingers are extended, and the base of the metacarpophalangeal joint (4) of the four fingers abuts against the top of the swing base (5) when the fingers are extended, so as to form a mechanical limit.

5. A fully direct-drive dexterous hand according to claim 1, characterized in that, Also includes: Wrist (10) is connected to the palm (9); The first fingertip sensor (1a) and the second fingertip sensor (1b) are respectively disposed at the ends of the distal interphalangeal joints (2) of the four fingers and the distal interphalangeal joint (13) of the thumb; The electronic control assembly includes a control board (11) disposed at the wrist (10) and a wiring harness, wherein the control board (11) is electrically connected to each direct drive motor and the fingertip sensor via the wiring harness.

6. A fully direct-drive dexterous hand according to claim 5, characterized in that, The top of the distal interphalangeal joint (2) of the four fingers, the proximal interphalangeal joint (3) of the four fingers and the metacarpophalangeal joint (4) of the four fingers are all provided with a first wiring groove, and the motor control wire in the wire harness is passed through the first wiring groove. The thumb metacarpophalangeal joint (12) and the distal interphalangeal joint (13) of the thumb are both provided with a second wiring groove. The base bracket (16) and the rotating base (17) are both provided with a wiring notch that communicates with the second wiring groove. The wire bundle passes through the second wiring groove and the wiring notch in sequence and is connected to the control board (11).

7. A fully direct-drive dexterous hand according to claim 1, characterized in that, The rotating shaft (15) has a threaded section that is threadedly connected to the swing base (5). The outer diameter of the sliding mating shaft section of the rotating shaft (15) located in the sliding groove is smaller than the groove width of the sliding groove. The shift fork (7) is connected to the output shaft of the swing direct drive motor (84) by screws so that when the swing base (5) swings, the rotating shaft (15) slides relative to the shift fork (7) along the sliding groove.

8. A fully direct-drive dexterous hand according to claim 1, characterized in that, The swing direct drive motor (84) is fixed to the palm (9) by the mounting position and the motor fixing plate (14), and the swing base (5) is rotatably mounted to the palm (9) by the two bearings (6).

9. A fully direct-drive dexterous hand according to claim 1, characterized in that, The rotation center lines of the output shafts of the second thumb direct drive motor (86) and the third thumb direct drive motor (87) are parallel to the extension direction of the thumb when it is extended; the thumb metacarpophalangeal joint (12) and the distal interphalangeal joint (13) of the thumb abut each other when the thumb is straightened to form a mechanical limit.

10. A control method for a fully direct-drive dexterous hand, characterized in that, The fully direct-drive dexterous hand according to claim 2 comprises: Obtain the target motion command of the dexterous hand, and determine the joints to be moved in the four-finger module and the thumb module and the driving state of the corresponding direct drive motor according to the target motion command; Control the rotation of the swing direct drive motor (84) corresponding to the four-finger module to be swung, so that the swing direct drive motor (84) drives the shift fork (7) to rotate. The shift fork (7) pushes the rotating shaft (15) to move through the sliding groove, and makes the rotating shaft (15) slide relative to the sliding groove, thereby driving the swing base (5) to swing around the center line of the bearing (6) to adjust the swing position of the corresponding four-finger module relative to the palm (9). According to the target action command, control at least one of the corresponding first four-finger direct drive motor (81), second four-finger direct drive motor (82) and third four-finger direct drive motor (83) to rotate, so that the output shaft of the corresponding direct drive motor directly drives the corresponding joints of the four-finger metacarpophalangeal joint (4), the four-finger proximal interphalangeal joint (3) and the four-finger distal interphalangeal joint (2) to rotate, so as to adjust the bending posture of the corresponding four-finger module; Control the first thumb direct drive motor (85) to rotate, drive the rotating base (17) to rotate through the output shaft of the first thumb direct drive motor (85), and drive the base bracket (16) and the thumb part connected to the base bracket (16) to swing relative to the palm (9) through the rotating base (17). According to the target action command, control at least one of the second thumb direct drive motor (86) and the third thumb direct drive motor (87) to rotate, so that the output shafts of the second thumb direct drive motor (86) and the third thumb direct drive motor (87) directly drive the corresponding joints of the thumb metacarpophalangeal joint (12) and the distal interphalangeal joint (13) to rotate, so as to adjust the bending posture of the thumb module.

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