A big thumb mechanism of a five-finger robot hand

Abstract

The big thumb mechanism of the five-finger mechanical hand disclosed by the application belongs to the field of robots. The big thumb mechanism is mainly composed of a finger bending assembly, a finger inboard swing assembly and a finger rotating around wrist assembly. The finger bending gear set is composed of a plurality of straight gears which are sequentially engaged. The finger bending assembly, the finger inboard swing assembly and the finger rotating around wrist assembly are combined on a mechanical big thumb, and the three degrees of freedom of the finger bending action, the finger inboard swing action and the finger rotating around wrist action can be simultaneously realized on the mechanical big thumb, so that the size of the mechanical big thumb is reduced. The connecting rod in the transmission mechanism of the finger bending assembly adopts a corrugated elastic connecting rod, so that the bending joint of the mechanical big thumb is elastic, the energy generated by the impact can be absorbed to protect the driving motor, the service life of the motor is improved, and the gripping configuration of the mechanical big thumb has self-adaptability in the gripping process, the acting area of the mechanical hand and the gripped object is increased, and the gripping stability of the mechanical hand is improved.

Description

Technical Field

[0001] This invention relates to a thumb mechanism for a five-fingered robotic hand used in humanoid robots, belonging to the field of robotics. Background Technology

[0002] One of the core functions of humanoid robots is to grasp and manipulate various objects and tools. A five-fingered robotic hand, by simulating the movements of a human hand, is an ideal solution for achieving this function. Among existing five-fingered robotic hand devices, cable-driven robotic hands are heavy and cannot integrate the transmission structure into the hand, while motor-driven robotic hands have high joint inertia and weak load-bearing capacity. Meanwhile, the thumb plays a crucial role in tasks such as manipulating objects, requiring high load capacity and high dexterity. Therefore, a highly integrated finger mechanical structure is needed to overcome these shortcomings. Summary of the Invention

[0003] To enhance the mobility and degrees of freedom of robotic hands, and considering factors such as size, load, compliant interaction, and impact variations, this invention provides a thumb mechanism for a five-finger robotic hand. This mechanism integrates a finger bending component, a finger inward swing component, and a finger wrist rotation component into a single mechanical thumb. This allows for simultaneous finger bending, inward swing, and wrist rotation movements on a single thumb, while reducing the overall size of the mechanical thumb. The linkage in the finger bending component's transmission mechanism uses a corrugated elastic linkage, making the thumb's bending joint elastic. This absorbs energy from impacts, protecting the drive motor and extending its lifespan. Simultaneously, it provides adaptive gripping configuration during the grasping process, increasing the contact area between the robotic hand and the grasped object, and improving the gripping stability of the robotic hand.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] The present invention discloses a thumb mechanism for a five-finger robotic hand, which mainly consists of a finger bending component, a finger inward swinging component, and a finger wrist rotation component.

[0006] The finger bending assembly mainly consists of a finger bending drive motor, a finger bending gear set, a finger bending ball screw and nut pair, a finger bending elastic connecting rod, and finger joints. The finger bending gear set is a gear set composed of multiple sequentially meshing spur gears. When the finger bending action is achieved, the drive motor provides rotational power to the gear set. This rotational power is transmitted to the shaft end of the ball screw via the meshing gear set, and the motion characteristics of the ball screw and nut pair convert the rotational motion into linear motion. The ball screw and nut then drive the finger joints to perform the finger bending action under the constraint of the finger bending elastic connecting rod. The finger joint mainly consists of a universal joint, an upper finger joint, a lower finger joint, and contact rubber.

[0007] As a preferred option, the finger bending elastic link adopts a corrugated elastic link, which makes the bending joint of the mechanical thumb elastic, can absorb the energy generated by the impact to protect the drive motor and improve the motor life. At the same time, it makes the gripping configuration of the mechanical thumb adaptive during the gripping process, increases the contact area between the robotic hand and the object being gripped, and improves the gripping stability of the robotic hand.

[0008] The finger inward swing assembly mainly consists of a finger inward swing drive motor, a finger inward swing gear set, a finger inward swing ball screw and nut pair, and two rotatable sliding baffles. The finger inward swing gear set is a gear set composed of multiple sequentially meshing spur gears. When the finger inward swing motion is achieved, the drive motor provides rotational power to the gear set. This rotational power is transmitted to the shaft end of the ball screw via the meshing spur gear set, and then the motion characteristics of the ball screw and nut pair convert the rotational motion into linear motion. The ball screw and nut drive the sliding baffles to rotate around their center, thus achieving the finger inward swing motion.

[0009] The mechanical thumb wrist-rotating assembly mainly includes a finger connector, a palm base, a drive motor, and a bevel gear set. The bevel gear set consists of a driving bevel gear and a driven bevel gear. When the mechanical thumb wrist-rotating assembly operates, the drive motor provides rotational power to the reversing bevel gear set. This rotational power is redirected by the meshing bevel gear set; the drive motor outputs rotational motion around the "X" axis, which is then redirected by the reversing bevel gear set to rotate around the "Y" axis, thus changing the direction of the rotational power. The driven gear in the bevel gear set drives the finger connector, causing the entire mechanical thumb to rotate around the wrist, thus achieving the mechanical thumb wrist-rotating motion.

[0010] The working method of the thumb mechanism of a five-finger robotic hand disclosed in this invention is as follows:

[0011] When the finger bending assembly realizes the finger bending action, the finger bending drive motor generates rotational motion during operation. This rotational motion is transmitted to the shaft end of the finger bending ball screw via the finger bending gear set. The finger bending ball screw and the finger bending ball nut together form the finger bending ball screw-nut pair. The rotational motion transmitted to the finger bending ball screw is converted into linear motion by the motion characteristics of the finger bending ball screw-nut pair and then output by the finger bending ball nut. The formula for calculating the output force of the finger bending ball nut is:

[0012]

[0013] Where F is the output force of the finger-bending ball nut, T is the torque on the end of the finger-bending ball screw shaft, I is the lead of the finger-bending ball screw, and η is the mechanical transmission efficiency.

[0014] The lower knuckle rotates around the universal joint, driven by the bending ball nut. This rotational power is transmitted to the upper knuckle via the bending elastic link, thus enabling the entire mechanical thumb to bend. When the upper knuckle contacts an object, the bending elastic link deforms elastically under the contact force, changing the bending angle of the mechanical thumb according to the magnitude of the contact force. This increases the contact area between the mechanical thumb and the object, improving the gripping stability of the robotic hand. When the upper knuckle is impacted, the bending elastic link deforms elastically under the impact force, absorbing the energy and protecting the drive motor, thus extending its lifespan.

[0015] When the finger inward swing assembly realizes the finger inward swing action, the finger inward swing drive motor generates rotational motion in the working state. This rotational motion is transmitted to the shaft end of the finger inward swing ball screw through the finger inward swing gear set. The finger inward swing ball screw and the finger inward swing ball nut together form the finger inward swing ball screw nut pair. The rotational motion transmitted to the finger inward swing ball screw is converted into linear motion by the motion characteristics of the finger inward swing ball screw nut pair and then output by the finger inward swing ball nut. The calculation formula of the output force of the finger inward swing ball nut is the same as that of formula (1). The finger inward swing ball nut drives the slide plate to rotate around the center of the plate, and thus the entire mechanical thumb swings inward around the center of the slide plate.

[0016] When the mechanical thumb wrist-rotating assembly performs the finger wrist-rotating motion, the finger wrist-rotating drive motor generates rotational motion, which drives the driving bevel gear. This rotational motion, initially around the "X" axis, is converted by the bevel gear set into rotational motion around the "Y" axis and output by the driven bevel gear. The driven gear then drives the finger connector to achieve rotational motion around the "Y" axis. Since the finger connector is fixed to the entire mechanical thumb, this ultimately achieves the wrist-rotating motion of the entire mechanical thumb.

[0017] Beneficial effects:

[0018] 1. The present invention discloses a thumb mechanism for a five-finger robotic hand, which combines three components—a finger bending component, a finger inward swing component, and a finger wrist rotation component—onto a single robotic thumb. This allows for the simultaneous realization of three degrees of freedom in a single robotic thumb: finger bending, finger inward swing, and finger wrist rotation, thereby reducing the overall size of the robotic thumb.

[0019] 2. The thumb mechanism of the five-finger robotic hand disclosed in this invention adopts a corrugated elastic connecting rod and a transmission structure of ball screw-slide plate, which converts the rotational motion of the motor into linear motion and then into joint rotational motion. Compared with the direct drive scheme, it can obtain a higher transmission ratio, improve load performance, and grip objects more firmly.

[0020] 3. The thumb mechanism of a five-finger robotic hand disclosed in this invention adopts a corrugated elastic link. The corrugated elastic link will undergo elastic deformation when subjected to force. Compared with a rigid link, the corrugated elastic link can absorb the energy generated by the impact to protect the drive motor and improve the motor life. At the same time, it makes the gripping configuration of the robotic thumb adaptive during the gripping process, increases the contact area between the robotic hand and the grasped object, and improves the gripping stability of the robotic hand.

[0021] 4. The thumb mechanism of a five-finger robotic hand disclosed in this invention integrates a direct drive motor, a ball screw-slide plate transmission structure and a corrugated elastic link, achieving three active degrees of freedom within a volume close to the size of a human thumb, and combining flexibility, load capacity and compliance. Attached Figure Description

[0022] Figure 1 This is a diagram illustrating the action of bending the fingers, where: Figure 1 (a) shows the mechanical thumb in the extended position. Figure 1 (b) shows the mechanical thumb in a bent position.

[0023] Figure 2 This is a schematic diagram of a corrugated elastic connecting rod.

[0024] Figure 3 This is a diagram illustrating the inward movement of the fingers, where: Figure 2 (a) shows the mechanical thumb in the extended position. Figure 2 (b) is the mechanical thumb in the inward swing state.

[0025] Figure 4 A diagram illustrating the finger wrist rotation motion: Figure 3 (a) is the initial state of the mechanical thumb. Figure 3 (b) shows the state of the mechanical thumb after it has rotated around the wrist.

[0026] Figure 5 A schematic diagram of the finger structure of this invention. Figure 4 (a) is a side view of a mechanical thumb. Figure 4 (b) is a front view of the mechanical thumb.

[0027] Among them: 1—finger bending component, 2—finger inward swinging component, 3—mechanical thumb wrist rotation component.

[0028] 1.1—Upper knuckle, 1.2—Finger bending elastic linkage, 1.3—Lower knuckle, 1.4—Universal joint, 1.5—Finger bending ball screw nut pair, 1.6—Finger bending guide shaft, 1.7—Finger bending drive motor, 1.8—Finger bending gear set.

[0029] Among them: 1.5—Finger-bending ball screw nut assembly includes 1.5.1—Finger-bending ball nut and 1.5.2—Finger-bending ball screw.

[0030] 2.1—Finger inward swing drive motor; 2.2—Finger inward swing gear set; 2.3—Finger inward swing ball screw nut pair; 2.4—Slide groove baffle; 2.5—Finger inward swing guide shaft.

[0031] Among them: 2.3—finger inward ball screw nut pair includes 2.3.1—finger inward ball screw and 2.3.2—finger inward ball nut.

[0032] 3.1—Frame, 3.2—Finger connector, 3.3—Palm base, 3.4—Reversing bevel gear set, 3.5—Finger wrist drive motor.

[0033] Among them: 3.4—the reversing bevel gear set includes 3.4.1—the driving bevel gear and 3.4.2—the driven bevel gear. Detailed Implementation

[0034] To better illustrate the purpose and advantages of the present invention, the invention will be further described below in conjunction with the accompanying drawings and examples.

[0035] Example 1:

[0036] like Figure 5 As shown in the figure, the thumb mechanism of a five-finger robotic hand disclosed in this embodiment is mainly composed of a finger bending component 1, a finger inward swinging component 2, and a finger wrist rotation component 3.

[0037] The finger bending assembly 1 mainly consists of a finger bending drive motor 1.7, a finger bending gear set 1.8, a finger bending ball screw nut pair 1.5, a finger bending elastic connecting rod 1.2, an upper finger joint 1.1, and a lower finger joint 1.3. The finger bending gear set 1.8 is a gear set composed of multiple sequentially meshing spur gears. When the finger bending assembly 1 performs a finger bending action, the finger bending drive motor 1.7 provides rotational power to the finger bending gear set 1.8. This rotational power is transmitted to the shaft end of the finger bending ball screw 1.5.2 via the meshing gear set, and the motion characteristics of the ball screw nut pair convert the rotational motion into linear motion. The finger bending ball nut 1.5.1 drives the upper finger joint 1.1 and the lower finger joint 1.3 to perform finger bending actions under the constraint of the finger bending elastic connecting rod 1.2 and the universal joint 1.4.

[0038] The finger bending elastic link 1.2 adopts a corrugated elastic link, which makes the bending joint of the mechanical thumb elastic, which can absorb the energy generated by the impact to protect the drive motor and improve the motor life. At the same time, it makes the gripping configuration of the mechanical thumb adaptive during the gripping process, increases the contact area between the robotic hand and the grasped object, and improves the gripping stability of the robotic hand.

[0039] The finger inward swing assembly 2 mainly consists of a finger inward swing drive motor 2.1, a finger inward swing gear set 2.2, a finger inward swing ball screw nut pair 2.3, and two rotatable sliding baffles 2.4. The finger inward swing gear set 2.2 is a gear set composed of multiple sequentially meshing spur gears. When the finger inward swing assembly 2 realizes the finger inward swing action, the finger inward swing drive motor 2.1 provides rotational power to the finger inward swing gear set 2.2. This rotational power is transmitted to the shaft end of the finger inward swing ball screw 2.3.1 via the meshing spur gear set, and then the rotational motion is converted into linear motion by the motion characteristics of the ball screw nut pair. The finger inward swing ball nut 2.3.2 drives the sliding baffles 2.4 to rotate around their center, thus realizing the finger inward swing action.

[0040] The mechanical thumb wrist-rotating assembly 3 mainly includes a finger connector 3.2, a palm base 3.3, a finger wrist-rotating drive motor 3.5, and a reversing bevel gear set 3.4. The reversing bevel gear set 3.4 consists of a driving bevel gear 3.4.1 and a driven bevel gear 3.4.2. When the mechanical thumb wrist-rotating assembly 3 performs its action, the finger wrist-rotating drive motor 3.5 provides rotational power to the reversing bevel gear set 3.4. This rotational power is redirected by the meshing bevel gear set; that is, the rotational direction output by the finger wrist-rotating drive motor 3.5 is rotational motion around the "X" axis, which is then redirected by the reversing bevel gear set 3.4 to rotational motion around the "Y" axis, thus changing the direction of the rotational power. The driven bevel gear 3.4.2 in the reversing bevel gear set 3.4 drives the finger connector 3.2, causing the entire mechanical thumb to rotate around the wrist with the wrist's rotation point as the axis, thereby realizing the mechanical thumb wrist-rotating action.

[0041] The working method of the thumb mechanism of a five-finger robotic hand disclosed in this embodiment is as follows:

[0042] When the finger bending assembly 1 performs the finger bending action, the finger bending drive motor 1.7 generates rotational motion in the working state. This rotational motion is transmitted to the shaft end of the finger bending ball screw 1.5.2 via the finger bending gear set 1.8. The finger bending ball screw 1.5.2 and the finger bending ball nut 1.5.1 together form the finger bending ball screw nut pair 1.5. The rotational motion transmitted to the finger bending ball screw 1.5.2 is converted into linear motion by the motion characteristics of the finger bending ball screw nut pair 1.5 and then output by the finger bending ball nut 1.5.1. The formula for calculating the output force of the finger bending ball nut 1.5.1 is as follows:

[0043]

[0044] Where F is the output force of the finger-bending ball nut 1.5.1, T is the torque on the shaft end of the finger-bending ball screw 1.5.2, I is the lead of the finger-bending ball screw 1.5.2, and η is the mechanical transmission efficiency.

[0045] The lower phalanx 1.3 is then rotated around the universal joint 1.4 by the bendable ball nut 1.5.1. The rotational power of the lower phalanx 1.3 is transmitted to the upper phalanx 1.1 via the bendable elastic link 1.2, thus realizing the bending action of the entire mechanical thumb. When the upper phalanx 1.1 contacts the object, the bendable elastic link 1.2 undergoes elastic deformation under the action of the contact force, causing the bending angle of the mechanical thumb to change with the magnitude of the contact force. This allows more of the mechanical thumb to contact the object, increasing the contact area between the robotic hand and the grasped object, and improving the gripping stability of the robotic hand. When the upper phalanx is subjected to an external impact, the bendable elastic link will undergo elastic deformation under the action of the impact force, absorbing the energy generated by the impact, thereby protecting the drive motor and improving the motor's lifespan.

[0046] When the finger inward swing assembly 2 realizes the finger inward swing action, the finger inward swing drive motor 2.1 generates rotational motion in the working state. This rotational motion is transmitted to the shaft end of the finger inward swing ball screw 2.3.1 through the finger inward swing gear set 2.2. The finger inward swing ball screw 2.3.1 and the finger inward swing ball nut 2.3.2 together form the finger inward swing ball screw nut pair 2.3. The rotational motion transmitted to the finger inward swing ball screw 2.3.1 is converted into linear motion by the motion characteristics of the finger inward swing ball screw nut pair 2.3 and then output by the finger inward swing ball nut 2.3.2. The calculation formula of the output force of the finger inward swing ball nut 2.3.2 is the same as that of formula (1). The finger inward swing ball nut 2.3.2 drives the slide plate 2.4 to rotate around the center of the plate. Thus, the entire mechanical thumb also swings inward around the center of the slide plate 2.4.

[0047] When the mechanical thumb wrist-rotating assembly consists of three parts, the wrist-rotating drive motor 3.5 generates rotational motion, driving the driving bevel gear 3.4.1. This rotational motion, initially around the "X" axis, is converted into rotational motion around the "Y" axis by the reversing bevel gear set 3.4, and output by the driven bevel gear 3.4.2. The driven gear drives the finger connector to achieve rotational motion around the "Y" axis. Since the finger connector 3.2 is fixed to the entire mechanical thumb, the entire mechanical thumb achieves wrist-rotating motion.

[0048] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A thumb mechanism for a five-finger robotic hand, characterized in that: It mainly consists of a finger bending component, a finger inward swinging component, and a finger wrist rotation component; The finger bending assembly mainly consists of a finger bending drive motor, a finger bending gear set, a finger bending ball screw nut pair, a finger bending elastic connecting rod, and a finger joint. The finger bending gear set is a gear set composed of multiple sequentially meshing spur gears. When the finger bending assembly realizes the finger bending action, the drive motor provides rotational power to the gear set. The rotational power is transmitted to the shaft end of the ball screw through the meshing gear set, and then the motion characteristics of the ball screw nut pair convert the rotational motion into linear motion. The ball nut drives the finger joint to perform the finger bending action under the constraint of the finger bending elastic connecting rod. The finger joint mainly consists of a universal joint, an upper finger joint, a lower finger joint, and contact soft rubber. The finger inward swing assembly mainly consists of a finger inward swing drive motor, a finger inward swing gear set, a finger inward swing ball screw nut pair, and two rotatable sliding groove baffles. The finger inward swing gear set is a gear set composed of multiple sequentially meshing spur gears. When the finger inward swing assembly realizes the finger inward swing action, the drive motor provides rotational power to the gear set. The rotational power is transmitted to the shaft end of the ball screw through the meshing spur gear set, and then the motion characteristics of the ball screw nut pair convert the rotational motion into linear motion. The ball screw nut drives the sliding groove baffles to rotate around the center of the sliding groove baffles, thereby realizing the finger inward swing action. The finger-wrist rotation assembly mainly consists of a finger connector, a palm base, a drive motor, and a bevel gear set. The bevel gear set consists of a driving bevel gear and a driven bevel gear. When the mechanical thumb wrist rotation assembly performs its action, the drive motor provides rotational power to the reversing bevel gear set. The rotational power is changed in direction by the meshing bevel gear set. That is, the rotational direction output by the drive motor is rotational motion around the "X" axis, and after passing through the reversing bevel gear set, the rotational direction is changed to rotational motion around the "Y" axis, thus realizing the change in the direction of rotational power. The driven gear in the bevel gear set drives the finger connector, so that the entire mechanical thumb rotates around the wrist with the rotation point of the wrist as the axis, thereby realizing the mechanical thumb wrist rotation action.

2. The thumb mechanism of a five-finger robotic hand as described in claim 1, characterized in that: The finger bending elastic link adopts a corrugated elastic link, which makes the bending joint of the mechanical thumb elastic, which can absorb the energy generated by the impact to protect the drive motor. At the same time, it makes the gripping configuration of the mechanical thumb adaptive during the gripping process, increasing the contact area between the robotic hand and the object being gripped, and improving the gripping stability of the robotic hand.

3. The thumb mechanism of a five-finger robotic hand as described in claim 1 or 2, characterized in that: When the finger bending assembly realizes the finger bending action, the finger bending drive motor generates rotational motion in the working state. This rotational motion is transmitted to the shaft end of the finger bending ball screw via the finger bending gear set. The finger bending ball screw and the finger bending ball nut together form the finger bending ball screw-nut pair. The rotational motion transmitted to the finger bending ball screw is converted into linear motion by the motion characteristics of the finger bending ball screw-nut pair and then output by the finger bending ball nut. The formula for calculating the output force of the finger bending ball nut is: Where F is the output force of the finger-bending ball nut, T is the torque on the end of the finger-bending ball screw shaft, I is the lead of the finger-bending ball screw, and η is the mechanical transmission efficiency. The lower knuckle rotates around the universal joint, driven by the bending ball nut of the finger. The rotational power of the lower knuckle is transmitted to the upper knuckle via the bending elastic link, thus realizing the bending action of the entire mechanical thumb. When the upper knuckle contacts an object, the bending elastic link undergoes elastic deformation under the action of the contact force, causing the bending angle of the mechanical thumb to change with the magnitude of the contact force. This allows more of the mechanical thumb to contact the object, increasing the contact area between the robotic hand and the object being grasped, and improving the gripping stability of the robotic hand. When the upper knuckle is impacted by an external force, the bending elastic link will undergo elastic deformation under the action of the impact force, absorbing the energy generated by the impact, thereby protecting the drive motor and improving the motor's lifespan. When the finger inward swing assembly realizes the finger inward swing action, the finger inward swing drive motor generates rotational motion in the working state. This rotational motion is transmitted to the shaft end of the finger inward swing ball screw through the finger inward swing gear set. The finger inward swing ball screw and the finger inward swing ball nut together form the finger inward swing ball screw nut pair. The rotational motion transmitted to the finger inward swing ball screw is converted into linear motion by the motion characteristics of the finger inward swing ball screw nut pair and then output by the finger inward swing ball nut. The calculation formula of the output force of the finger inward swing ball nut is the same as that of formula (1). The finger inward swing ball nut drives the slide plate to rotate around the center of the plate. Then the entire mechanical thumb also swings inward around the center of the slide plate. When the mechanical thumb wrist rotation assembly performs the finger wrist rotation action, the finger wrist rotation drive motor generates rotational motion in the working state, driving the active bevel gear. This rotational motion is converted from rotational motion around the "X" axis to rotational motion around the "Y" axis by the bevel gear set and output by the driven bevel gear. The driven wheel drives the finger connector to achieve rotational motion around the "Y" axis. Since the finger connector is fixed to the entire mechanical thumb, the entire mechanical thumb wrist rotation action is thus realized.

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