Dexterous hand

Abstract

The application discloses a dexterous hand, and relates to the technical field of a dexterous hand of a robot, and the dexterous hand comprises a forearm assembly, a wrist joint, a palm assembly, a finger assembly and a tendon transmission, the forearm assembly comprises a forearm shell and a driving motor set, a winding wheel set and a ratchet tensioning mechanism arranged in the interior of the forearm shell; the wrist joint is connected with the top end of the forearm assembly; the palm assembly is arranged at the top end of the wrist joint; a plurality of finger assemblies are hinged on the palm assembly; the tendon transmission is connected with the finger assembly at one end and is anchored after passing through the winding wheel set at the other end; the winding wheel set of each driving channel is coaxially provided with the ratchet tensioning mechanism in the application; when tensioning is performed, the driving motor set is powered on to lock the winding wheel, an operator rotates the ratchet to wind and unwind the tendon by hand, and the one-way ratchet is self-locked to prevent back-off; the whole hand tensioning and subsequent maintenance can be completed without any special tooling.

Description

Technical Field

[0001] This invention relates to the field of robot dexterity hand technology, specifically to a dexterity hand. Background Technology

[0002] Existing humanoid dexterous hands have the following drawbacks: 1. Linkage direct-drive dexterous hands have low degrees of freedom (six to twelve), thick fingers, poor anthropomorphism, and are difficult to replicate the finger-pinching and dexterous operation of human hands; 2. High-degree-of-freedom tendon-driven hands rely on precision-machined parts and special tensioning fixtures, resulting in high manufacturing and maintenance costs and long cycles; 3. The installation and adjustment of tendon ligament tension relies on the technician's feel, lacks quantitative acceptance criteria, and has poor consistency between different batches; there is a lack of identifiable detection methods for abnormal tension (too tight / too loose / tendon ligament jamming); 4. When the drive motor is concentrated in the forearm, there is a lack of systematic heat dissipation design, which limits the temperature rise during continuous operation. Summary of the Invention

[0003] This invention provides a dexterous hand, which aims to solve the problems of low degree of freedom, high manufacturing and maintenance costs, reliance on feel for tension adjustment and lack of quantitative criteria, and insufficient heat dissipation in existing dexterous hands.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A dexterous hand includes: A forearm assembly, comprising a forearm housing and a drive motor assembly, a winding wheel assembly, and a ratchet tensioning mechanism disposed inside the forearm housing; The wrist joint is connected to the top of the forearm assembly; A hand assembly is located at the top of the wrist joint; Multiple finger assemblies are hinged to the palm assembly; The tendon cable drive has one end connected to the finger assembly and the other end wrapped around and anchored to the winding pulley assembly; The drive motor assembly is used to drive the winding wheel assembly to rotate, so as to drive the finger assembly to move through the tendon rope transmission. The ratchet tensioning mechanism is coaxially arranged with the winding wheel assembly and is used to adjust and lock the tension of the tendon rope transmission.

[0005] As a preferred embodiment of the present invention, the ratchet tensioning mechanism includes a ratchet disc, a one-way pawl, and a tensioning knob. The tensioning knob drives the ratchet disc to rotate to gradually tighten and loosen the tendon rope transmission. The one-way pawl engages with the ratchet disc to achieve one-way self-locking.

[0006] As a preferred embodiment of the present invention, the drive motor assembly is composed of multiple serial bus magnetic coded servo mechanisms, which are fixed inside the forearm assembly in a double-row tower arrangement.

[0007] As a preferred embodiment of the present invention, the magnetic encoding resolution of the serial bus magnetically encoded servo is 0.088°.

[0008] As a preferred embodiment of the present invention, it further includes a cooling fan, which is disposed inside the forearm housing and is used to form a through-flow duct that runs through the drive motor assembly inside the forearm assembly.

[0009] As a preferred embodiment of the present invention, the cooling fan includes an intake fan and an exhaust fan respectively installed on opposite side walls of the forearm housing, and the intake fan and the exhaust fan are connected in series in the same direction to form the through-flow duct.

[0010] As a preferred embodiment of the present invention, both the intake fan and the exhaust fan are 12V DC axial fans with dimensions of 50×50×10mm.

[0011] As a preferred embodiment of the present invention, the tendon cable is a high-strength ultra-high molecular weight polyethylene braided thread, one end of which is anchored in a knotting hole at the end of the finger bone of the finger assembly that matches the thread diameter.

[0012] As a preferred embodiment of the present invention, the forearm housing is a rectangular rounded corner tower-shaped cavity, which is integrally formed by additive manufacturing.

[0013] As a preferred embodiment of the present invention, the drive motor assembly comprises seventeen units, of which sixteen are used to drive the metacarpophalangeal, proximal, and abduction joints of the finger assembly, and one unit is used to drive the wrist joint, thus forming a total of seventeen active degrees of freedom.

[0014] This invention provides a dexterous hand. It has the following beneficial effects: 1. This invention enables ratchet tensioning without tooling: Each drive channel's winding wheel assembly is coaxially equipped with a ratchet tensioning mechanism: During tensioning, the drive motor unit is fully energized and locks the winding wheels, allowing the operator to manually rotate the ratchet step by step to wind and release the tendon rope. The one-way ratchet teeth self-lock to prevent backlash; full manual tensioning and subsequent maintenance can be completed without any special tooling.

[0015] 2. This invention features a quantitative stroke acceptance calibration: After tensioning is completed, automatic calibration is performed: the torque is enabled by grouping joints, and the stroke is recorded bidirectionally for each joint; the measured stroke is compared with a preset "acceptance band" (a stroke range defined according to the joint type). If the stroke falls off the band, the tension is deemed acceptable; if the stroke is too large, it is deemed too loose; if it is too small, it is deemed too tight; if there is no response to ratchet adjustment, the tendon rope is deemed stuck. This establishes a quantitative mapping between "tension state and stroke value," replacing manual adjustment and supporting a closed-loop convergence process of "adjust one notch - measure once." The calibration results directly generate a joint-motor mapping file for use by the control layer.

[0016] 3. The present invention has a high-efficiency heat dissipation structure: an intake fan and an exhaust fan are arranged opposite each other on both sides of the forearm housing to form a through air duct that runs through the motor tower, ensuring thermal balance during continuous operation.

[0017] 4. This invention provides four levels of protection for the control link: travel clamping, single-machine current limit, bus current budget protection, and overheat protection.

[0018] 5. In this invention, the stroke acceptance of all 17 joints enters the preset "acceptance zone", with a high pass rate; no vibration is detected in the static holding state; after 15 repeated positioning tests, the position distribution is qualified and reaches the encoder resolution level; the material cost of the whole machine is about one-tenth of that of foreign products with the same degree of freedom. Attached Figure Description

[0019] Figure 1 This is a three-dimensional view of the dexterous hand device of the present invention; Figure 2 This is a front view of the dexterous hand device of the present invention; Figure 3 This is a schematic diagram of the internal structure of the forearm of the present invention; Figure 4 This is a schematic diagram of the ratchet tensioning mechanism of the present invention; Figure 5 This is a schematic diagram of the cross-section of the cross-ventilation cooling duct of the present invention; Figure 6 This is the electrical schematic diagram of the present invention.

[0020] In the picture: 100. Forearm assembly; 110. Drive motor assembly; 120. Winding wheel assembly; 130. Ratchet tensioning mechanism; 131. Ratchet disc; 132. One-way pawl; 133. Tensioning knob; 140. Cooling fan; 141. Intake fan; 142. Exhaust fan; 143. Through-flow air duct; 150. Forearm housing; 160. Power supply terminal; 200. Wrist joint; 300. Hand assembly; 400. Finger assembly; 410. Thumb assembly; 440. Tendon cable drive; 600. Host computer; 610. Bus driver board; 620. Power supply module. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] Please see Figures 1-6 The present invention provides a dexterous hand, which includes a forearm assembly 100, a wrist joint 200, a palm assembly 300, a finger assembly 400, and a tendon cable transmission 440, as described in detail below: Please see Figure 1 and Figure 2 The wrist joint 200 connects the top of the forearm assembly 100 to the palm base of the hand assembly 300, and is directly driven by a dual-output shaft motor at the top of the tower. The hand assembly 300 has a hollow palm structure, with four sets of finger assemblies 400 hinged in parallel at the distal end, and the thumb assembly 410 hinged obliquely on the radial side. Each finger assembly contains three segments of phalanges: proximal phalanx, middle phalanx, and distal phalanx. Adjacent phalanges are hinged through joint shafts with built-in bearings. The flexion, extension, and abduction of each joint are driven by the contraction and release of the corresponding channel tendon ropes. The seventeen active degrees of freedom reproduce the original operations of human hand grasping, pinching, twisting, and pressing. Please see Figure 3 and Figure 4 The forearm assembly 100 includes a forearm housing 150 and a drive motor assembly 110, a winding wheel assembly 120, a ratchet tensioning mechanism 130, and a cooling fan 140 fixedly installed inside it. The forearm housing 150 is a rectangular rounded corner tower-shaped cavity, which is integrally formed by additive manufacturing. The top end is fixedly connected to the wrist joint 200, and the bottom end is provided with a mounting base. A power supply terminal 160 is provided on one side of the base. Please see Figure 3 The drive motor assembly 110 consists of seventeen serial bus magnetically encoded servos (not fully shown in the figure due to perspective), with specifications of 20×34mm and magnetic encoding resolution of 0.088°. They are connected via a single daisy-chain bus. Sixteen of them drive the metacarpophalangeal, proximal, and abduction joints of the four fingers and thumb assembly 410 via tendon cords 440, and one drives the wrist joint 200, for a total of seventeen active degrees of freedom. All structural components are integrally molded using additive manufacturing. The finger joints have built-in bearings. The tendon cords are made of high-strength ultra-high molecular weight polyethylene braided wire, with wiring in conjunction with guide grooves and PTFE conduits. The drive motor assembly 110 is fixed inside the forearm housing 150 in a double-row tower arrangement. From the top of the tower to the bottom of the tower, they are connected one by one via a serial bus daisy chain in a fixed chain sequence. The wrist drive motor (not shown in the figure) is placed on the top of the tower. The output shaft of each motor is coaxially fixedly mounted with a winding wheel assembly 120. Please see Figure 4The ratchet tensioning mechanism 130 is coaxially arranged with the winding wheel assembly 120, including a ratchet disc 131, a one-way pawl 132, and a tensioning knob 133. The ratchet disc 131 is coaxially arranged with the winding wheel assembly 120 (i.e., mounted on the output shaft of the drive motor assembly 110). The ratchet disc 131 rotates with the tensioning knob 133 to take in the line step by step. The pawl 132 is rotatably arranged inside the forearm housing 150. At the same time, the pawl 132 and the ratchet disc 131 engage in one-way engagement. The one-way engagement between the pawl 132 and the ratchet disc 131 prevents retraction. Lifting the pawl 132 will release the line. During the tensioning operation, the drive motor is energized to lock the wheel system. The operator can complete the tension adjustment step by step. No tooling is required throughout the process. The tendon cable transmission 440 uses high-strength ultra-high molecular weight polyethylene braided wire. One end of the wire is anchored in a knotting hole that matches the wire diameter at the end of the finger bone. The middle section is routed through a PTFE conduit and a guide groove in the structural component. The other end is wound around and anchored to the winding wheel assembly 120. Please see Figure 5 Fan positions are provided on the opposite side walls of the forearm housing 150 to install cooling fan groups. Specifically, an intake fan 141 and an exhaust fan 142 are installed in the fan positions respectively. Both fans are 12V DC axial fans with a specification of 50×50×10mm. The intake fan 141 and the exhaust fan 142 are connected in series in the same direction to form a through-flow duct 143 that runs through the gap between the motor towers. The power supply for the fans is led out from one side of the power supply terminal 160 and is wired separately from the serial bus signal line and does not come into contact with each other. Please see Figure 6 The host computer 600 and the bus driver board 610 are bidirectionally electrically connected via USB bus; the bus driver board 610 is electrically connected to the first motor of the drive motor group 110, and the seventeen motors are connected in a daisy chain according to the chain order, sharing the same half-duplex serial bus; the power supply module 620 (12V DC) is electrically connected to the power bus of the bus driver board 610 and the cooling fan 140 respectively. This invention allows for ratchet tensioning without the need for tooling: Each drive channel's winding wheel assembly 120 is coaxially equipped with a ratchet tensioning mechanism 130: during tensioning operations, the drive motor assembly 110 is fully energized and locks the winding wheel, allowing the operator to manually rotate the ratchet step by step to wind and release the tendon rope. The one-way ratchet self-locks to prevent backlash; full manual tensioning and subsequent maintenance can be completed without any special tooling. This invention quantifies the acceptance calibration of the travel distance: After tensioning is completed, automatic calibration is performed: the torque is enabled by grouping joints, and the stroke is recorded bidirectionally for each joint; the measured stroke is compared with the preset "acceptance band" (the stroke range defined according to the joint type). If the stroke falls off the band, the tension is deemed acceptable; if the stroke is too large, it is deemed too loose; if it is too small, it is deemed too tight; if there is no response to ratchet adjustment, it is deemed that the tendon rope is stuck. This establishes a quantitative mapping between "tension state and stroke value", replacing manual adjustment, and supporting a closed-loop convergence process of "adjust one step - measure once". The calibration results directly generate a joint-motor mapping file for use by the control layer. This invention features a highly efficient heat dissipation structure: An intake fan 141 and an exhaust fan 142 are arranged opposite each other on both sides of the forearm housing 150, forming a through-draft air duct that runs through the motor tower (see...). Figure 5 ), to ensure thermal balance during continuous operation; This invention provides four levels of protection for the control link: travel clamping, single-machine current limit, bus current budget protection, and overheat protection. The superior command is sent to each servo motor via the protection chain, and the tendon rope is wound and released by the winding wheel to drive each finger joint; when gripping, the pretension of the tendon rope ensures the transmission stiffness and absorbs gear backlash.

[0023] The dexterous hand of this invention has the following superior properties: Travel acceptance: All 17 joints passed the travel acceptance test and entered the preset "acceptance zone", with a high pass rate; Stationary jitter: No jitter was detected while the object was stationary. Repeated positioning: After 15 repeated positioning tests, the position distribution is qualified and reaches the encoder resolution level. Cost advantage: The total material cost of the machine is approximately one-tenth of that of foreign products with the same degree of freedom; This product is developed in pairs for left-hand and right-hand use, with the two configurations being mirror images of each other: the palm, fingers, tendon cable routing, and forearm motor tower layout are all mirror symmetrical. The mechanism principle, electrical connection, control parameters, and assembly and adjustment methods are completely identical. This embodiment uses the right-hand configuration as an example for illustration, while the left-hand configuration is its mirror embodiment. Both fall within the scope of protection claimed in this application.

[0024] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A dexterous hand, characterized in that, include: The forearm assembly (100) includes a forearm housing (150) and a drive motor assembly (110), a winding wheel assembly (120) and a ratchet tensioning mechanism (130) disposed inside the forearm housing (150). The wrist joint (200) is connected to the top of the forearm assembly (100); A hand assembly (300) is disposed at the top of the wrist joint (200); Multiple finger assemblies (400) are hinged to the palm assembly (300); A tendon cable drive (440) has one end connected to the finger assembly (400) and the other end wrapped around the winding wheel assembly (120) and anchored thereto; The drive motor assembly (110) is used to drive the winding wheel assembly (120) to rotate, so as to drive the finger assembly (400) to move through the tendon cord drive (440). The ratchet tensioning mechanism (130) is coaxially arranged with the winding wheel assembly (120) and is used to adjust and lock the tension of the tendon cord drive (440).

2. A dexterous hand according to claim 1, characterized in that, The ratchet tensioning mechanism (130) includes a ratchet disc (131), a one-way pawl (132), and a tension knob (133). The tension knob (133) drives the ratchet disc (131) to rotate to gradually tighten and loosen the tendon cable transmission (440). The one-way pawl (132) engages with the ratchet disc (131) to achieve one-way self-locking.

3. A dexterous hand according to claim 1, characterized in that, The drive motor assembly (110) is composed of multiple serial bus magnetic coded servo mechanisms, which are fixed inside the forearm assembly (100) in a double-row tower arrangement.

4. A dexterous hand according to claim 3, characterized in that, The magnetic encoding resolution of the serial bus magnetically encoded servo is 0.088°.

5. A dexterous hand according to claim 1, characterized in that, It also includes a cooling fan (140), which is disposed inside the forearm housing (150) to form a through-flow duct (143) through the drive motor assembly (110) inside the forearm assembly (100).

6. A dexterous hand according to claim 5, characterized in that, The cooling fan (140) includes an intake fan (141) and an exhaust fan (142) respectively installed on opposite side walls of the forearm housing (150). The intake fan (141) and the exhaust fan (142) are connected in series in the same direction to form the through air duct (143).

7. A dexterous hand according to claim 6, characterized in that, Both the intake fan (141) and the exhaust fan (142) are 12V DC axial fans with a specification of 50×50×10mm.

8. A dexterous hand according to claim 1, characterized in that, The tendon cord drive (440) is a high-strength ultra-high molecular weight polyethylene braided thread, one end of which is anchored in a knotting hole at the end of the finger bone of the finger assembly (400) that matches the thread diameter.

9. A dexterous hand according to claim 1, characterized in that, The forearm housing (150) is a rectangular, rounded-corner tower-shaped cavity, integrally formed by additive manufacturing.

10. A dexterous hand according to claim 1, characterized in that, The drive motor assembly (110) consists of seventeen units, of which sixteen are used to drive the metacarpophalangeal, proximal, and abduction joints of the finger assembly (400), and one is used to drive the wrist joint (200), thus forming a total of seventeen active degrees of freedom.

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