Rigid-flexible coupling pneumatic humanoid dexterous finger and dexterous hand

Abstract

The invention belongs to the technical field related to medical robots, and discloses a rigid-flexible coupling pneumatic humanoid dexterous finger and a dexterous hand. The dexterous finger comprises a sectional corrugated pipe actuator, a rigid cover plate, a rigid bottom plate, a flexible finger pulp patch and a one-way stretchable fabric; a cooperative structure of rigid supporting, flexible driving and contact adaptation is formed through a preset assembly relation; by designing the wave number of the corrugated pipe at each joint of the pneumatic dexterous finger, the bending proportion of each joint is ensured to accord with the human hand movement rule; the one-way stretchable fabric can restrain ineffective upheaval at the joints, and the energy conversion efficiency is improved. The dexterous hand can integrate five anthropomorphic-size dexterous fingers, and the palm notch angle, the thumb turning direction angle and the flexible palm patch are all engraved with the physiological characteristics and structure of the hand of the human body. According to the pneumatic dexterous hand, personification of the pneumatic dexterous hand in appearance and movement modes is achieved, flexibility and bearing stability are both considered, and the pneumatic dexterous hand can meet the requirements of multiple scenes such as medical care and industrial assembly.

Description

Technical Field

[0001] This invention belongs to the field of medical robot technology, and more specifically, relates to a rigid-flexible coupled pneumatic anthropomorphic dexterous finger and dexterous hand. Background Technology Fingers are the core part of the human body for fine motor skills and daily grasping. Their motor function relies on the coordinated action of a combination of rigid and flexible structures such as bones, muscles, and tendons. This natural rigid-flexible coupling characteristic allows fingers to maintain good flexibility and adaptability while possessing strong output force and lateral load-bearing capacity. Currently, the demand for humanoid hand manipulation devices is increasingly urgent in many fields such as medicine, industry, and services. In the medical field, patients with missing fingers need humanoid prostheses to restore daily functions such as grasping water cups and buttoning buttons; rehabilitation robots need flexible assistance to avoid joint damage; minimally invasive surgical robots need to precisely grasp tissues without causing tearing; elderly care robots need to gently and drop-proofly grasp tableware; and commercial robots need to shake hands and hand over items in a natural, human-like manner.

[0002] Most existing dexterous hands employ purely rigid or purely flexible structures. While rigid dexterous hands possess strong output force and controllable motion, they lack compliance and are insufficiently safe. Flexible dexterous hands, on the other hand, are prone to ineffective deformation due to their overly flexible structure, resulting in insufficient output force and limited load-bearing capacity. These issues render existing dexterous hands inadequate in terms of anthropomorphic form, stability, and overall performance.

[0003] The rigid-flexible coupling design concept proposed in recent years introduces a rigid structure into a flexible drive unit, thereby balancing compliance and stability. "Soft master-rigid slave" structures achieve the main motion through flexible drive, while the rigid structure acts as a skeleton to provide motion guidance and displacement constraints, thus improving stability and load-bearing capacity while ensuring compliance.

[0004] However, existing technologies still suffer from limitations such as a low degree of anthropomorphism in the motion of soft actuators, and the tendency for bulges or lateral deflections to occur at joints, resulting in insufficient motion precision. The output force of dexterous fingers is limited, making it difficult to meet the stability requirements of everyday grasping tasks. Furthermore, existing structures differ significantly from human hands in appearance and movement, lacking anthropomorphic features. Therefore, there is an urgent need to design a rigid-flexible coupled pneumatic anthropomorphic dexterous finger and hand. Summary of the Invention

[0005] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a rigid-flexible coupled pneumatic anthropomorphic dexterous finger and dexterous hand, thereby solving the technical problems of low anthropomorphism, insufficient motion accuracy, limited output force and difficulty in balancing rigidity and flexibility in the existing pneumatic dexterous hand.

[0006] To achieve the above objectives, according to one aspect of the present invention, a rigid-flexible coupled pneumatic anthropomorphic dexterous finger is provided, comprising a segmented bellows actuator, a rigid cover plate, a rigid base plate, a flexible fingertip patch, and a unidirectional stretchable fabric; the straight section of the segmented bellows actuator is clamped and fixed between the rigid cover plate and the rigid base plate, and the bellows section of the segmented bellows actuator is arranged at the joint corresponding position of the dexterous finger; adjacent rigid base plates are hinged together; the unidirectional stretchable fabric is coupled to the back side of the rigid base plate, and the unidirectional stretchable fabric is stretchable along the axial direction of the finger but not stretchable along the radial direction of the finger; the flexible fingertip patch is coupled to the contact side of the rigid base plate.

[0007] Preferably, the overall dimensions and length ratio of each phalanx of the dexterous finger are designed in an anthropomorphic manner based on human finger anatomy data, and the crest radius of the corrugated pipe section is smaller than the cross-sectional radius of the corresponding human finger part.

[0008] Preferably, the corrugated tube segments corresponding to the metacarpophalangeal joints, proximal interphalangeal joints, and distal interphalangeal joints of the dexterous fingers have different wave numbers, so that the bending angle ratio of each joint under air pressure drives conforms to the preset bending angle ratio of human hand joints.

[0009] Preferably, the ratio of the joint bending angles of the dexterous fingers is set as follows: metacarpophalangeal joint: proximal interphalangeal joint: distal interphalangeal joint = 6:8:7.

[0010] Preferably, the adjacent rigid base plates are hinged together by bearings and pins; the straight pipe section of the segmented bellows actuator is rigidly coupled and fixed by screws and nuts to the bellows straight pipe section, the rigid cover plate and the rigid base plate.

[0011] According to another aspect of the present invention, a rigid-flexible coupled pneumatic humanoid dexterous hand is provided, comprising a palm structure and five rigid-flexible coupled pneumatic humanoid dexterous fingers as described above; the palm structure includes a hand plate mechanism, on which five mounting notches are provided for mounting the five dexterous fingers respectively; and further includes a flexible palm patch coupled to the palm side of the hand plate mechanism.

[0012] Preferably, the plane of the mounting notch for mounting the four fingers other than the thumb forms an angle with the main plane of the hand mechanism, which matches the physiological angle between the proximal phalanx of the corresponding finger and the palm plane in a naturally relaxed state; the plane of the mounting notch for mounting the thumb forms a rotation angle with the main plane of the hand mechanism, which matches the opposing posture of the thumb when the hand is naturally relaxed, and a crescent groove is provided on the inner side of the notch.

[0013] Preferably, the plurality of flexible palm patches are made of highly elastic silicone and are respectively configured as biomimetic structures that match the palm pads, hypothenar pads, and thenar pads.

[0014] Preferably, the five dexterous fingers include a dexterous thumb, a dexterous index finger, a dexterous middle finger, a dexterous ring finger, and a dexterous little finger, and the size and joint length ratio of each finger are designed based on the anatomical data of the corresponding human fingers.

[0015] Preferably, it also includes a back shell of the hand that is detachably connected to the hand plate mechanism; the air ducts of each of the dexterous fingers converge through a preset channel to an air duct outlet provided on the palm structure.

[0016] In summary, compared with the prior art, the rigid-flexible coupled pneumatic anthropomorphic dexterous finger and dexterous hand provided by the present invention have the following beneficial effects: 1. The pneumatic anthropomorphic dexterous finger of this invention uses a segmented bellows actuator as the core driving component, combined with components such as a rigid base plate, rigid cover plate, unidirectional stretchable fabric, flexible fingertip patch, and bearings, forming a collaborative structure of "rigid support - flexible drive - contact adaptation" through a preset assembly relationship. By designing the number of bellows at each joint of the pneumatic dexterous finger, the bending ratio of each joint is ensured to conform to the movement law of the human hand. The rigid support gives the dexterous finger and dexterous hand sufficient rigidity and strength to resist lateral swinging, the flexible drive can drive the bellows actuator by increasing or decreasing air pressure, and the contact adaptation increases the gripping friction and improves gripping stability.

[0017] 2. The pneumatic anthropomorphic dexterous finger of the present invention is based on human finger anatomical data: according to the overall length differences of different human fingers and the length ratio of the proximal, middle, and distal phalanges of each finger, the shape, size, and movement trajectory of the dexterous finger are anthropomorphically designed. In terms of structural assembly, the straight pipe section of the bellows actuator is rigidly coupled to the rigid base plate and rigid cover plate through screws, which not only ensures the stable connection between the actuator and the support structure, but also provides a rigid reference for pneumatic drive; adjacent rigid base plates are hinged together by bearings and pins. This connection method allows adjacent phalanges to rotate flexibly around the hinge axis, simulating the bending movement characteristics of human finger joints.

[0018] 3. The pneumatic anthropomorphic dexterous hand of the present invention can integrate five dexterous fingers of anthropomorphic size. The palm notch angle, thumb rotation angle and flexible palm patch all replicate the physiological characteristics and structure of the human hand. The overall size follows ergonomics. The length and width of the palm are similar to the average size of an adult male's palm. It can complete a variety of human hand grasping methods. It realizes the anthropomorphism of the pneumatic dexterous hand in appearance, movement scale and grasping performance, taking into account both flexibility and load-bearing stability. It can be adapted to the needs of multiple scenarios such as medical care and industrial assembly.

[0019] 4. This invention wraps the pneumatic dexterous hand fingers with a coupled unidirectional stretchable fabric on all sides except the rigid base plate. This fabric has significant anisotropic mechanical properties, exhibiting extremely high elasticity in the axial direction along the finger length, with a stretch rate that meets deformation requirements. It can deform synchronously with the finger's bending movement without hindering the flexion and extension movements of the dexterous finger. However, it is in a non-stretchable state in the radial direction of the actuator perpendicular to the axial direction, which can effectively limit the bulging deformation of the bellows at the joint through radial constraint. This allows the pneumatic energy applied to the actuator to be converted into bending driving force more efficiently, significantly improving the bending efficiency and output force of the dexterous finger. Attached Figure Description

[0020] Figure 1 This is an internal schematic diagram of the pneumatic dexterous finger of the present invention; Figure 2 This is an external schematic diagram of the pneumatic dexterous finger of the present invention; Figure 3 This is a cross-sectional view of the pneumatic dexterous finger of the present invention; Figure 4 This is a schematic diagram showing the dimensions of the pneumatic dexterous finger of the present invention; Figure 5 This is a schematic diagram of the corrugated pipe sections at each joint of the pneumatic dexterous finger of the present invention bending at different wave numbers; Figure 6 This is a diagram of a human finger; Figure 7 This is a schematic diagram of the palm of the pneumatic dexterous hand of the present invention; Figure 8 This is a schematic diagram of the back of the hand of the pneumatic dexterous hand of the present invention; In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-Segmented bellows actuator; 2-Rigid cover plate; 3-Rigid base plate; 4-Flexible fingertip patch; 5-Base plate small hole; 6-Screw; 7-Nut; 8-Bearing; 9-Pin; 10-One-way stretchable fabric; 11-Trachea; 12-Flexible palm patch; 12-1 Palmar pad; 12-2 Hypothenar pad; 12-3 Thenar pad; 13-Back of hand shell; 14-Trachea outlet; 15-Dexterous thumb; 16-Dexterous index finger; 17-Dexterous middle finger; 18-Dexterous ring finger; 19-Dexterous little finger; 20-Distal dorsal fold; 21-Middle dorsal fold; 22-Proximal dorsal fold; 23-Distal fold; 24-Middle fold; 25-Proximal fold; 26-Hand mechanism. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Example 1 Please see Figure 1-3 This embodiment of the rigid-flexible coupling pneumatic anthropomorphic dexterous finger includes a segmented bellows actuator 1, a rigid cover plate 2, a rigid base plate 3, a flexible fingertip patch 4, a small hole 5 in the base plate, a screw 6, a nut 7, a bearing 8, a pin 9, a unidirectional stretchable fabric 10, and an air tube 11. The straight section of the segmented bellows actuator 1, through the cooperation of the screw 6 and the nut 7, forms a rigid coupling and fixation between the bellows straight section, the rigid cover plate 2, and the rigid base plate 3. This connection method can significantly improve the overall structural rigidity of the dexterous finger, similar to the phalanges of a human finger. The bellows section of the segmented bellows actuator 1 is arranged at the joint corresponding position of the dexterous finger, serving as the core driving component for joint bending. The adjacent rigid base plate 3 is hinged through the bearing 8 and the pin 9, providing stable support and a flexible rotation axis for joint rotation. This allows for natural bending movements of the dexterous finger, covering the main range of motion of the human finger, in conjunction with the deformation of the bellows section under air pressure.

[0023] Specifically, on the back side of the dexterous finger, a unidirectional stretchable fabric 10 is sewn together with a rigid base plate 3 through small holes 5 in the base plate, making them tightly coupled. The unidirectional stretchable fabric 10 is stretchable along the axial direction of the finger but not stretchable along the radial direction. This fabric can be easily stretched along the axial direction (length direction) of the finger to accommodate bending movements; however, it is almost not stretchable in the radial direction (finger thickness direction). In this application, the unidirectional stretchable fabric 10 is wrapped and coupled on the other sides of the dexterous finger except for the rigid base plate. This fabric has significant anisotropic mechanical properties: it has extremely high elasticity in the axial direction along the length of the finger, and the elongation rate meets the deformation requirements, allowing it to deform synchronously with the bending movement of the finger without hindering the flexion and extension movements of the dexterous finger; while in the radial direction of the actuator perpendicular to the axial direction, it is in a non-stretchable state, which can effectively limit the bulging deformation of the bellows at the joint through radial constraint, thereby converting the pneumatic energy applied to the actuator into bending driving force more efficiently, significantly improving the bending efficiency and output force of the dexterous finger.

[0024] Specifically, a flexible fingertip patch 4 made of highly elastic silicone is attached to the contact side of the rigid base plate 3 on the ventral side (gripping surface) of the finger. Corresponding to the position of the human fingertip, the patch deforms when grasping an object, increasing the contact area and friction, and adapting to the contour of the object.

[0025] Please see Figure 6 A diagram of human fingers, where 20 represents the distal dorsal crease, 21 represents the middle dorsal crease, 22 represents the proximal dorsal crease, 23 represents the distal crease, 24 represents the middle crease, and 25 represents the proximal crease; please refer to [link / reference]. Figure 4 The overall dimensions of the dexterous fingers are designed strictly according to human finger anatomy data to ensure a realistic appearance. The corrugated tube's crest radius is also designed to be smaller than the cross-sectional radius of the corresponding part of a real finger. Indicates the length of the proximal phalanx. Indicates the length of the middle phalanx. Indicates the length of the distal phalanx; the distance from the tip of the middle finger to the distal dorsal crease (20°). Distance from fingertip to distal finger crease 23 Similar, and the distance from the distal dorsal fold 20 to the middle dorsal fold 21 Distance from distal finger fold 23 to intermediate finger fold 24 Similar, but the distance from the middle dorsal fold 21 to the proximal dorsal fold 22 is... Significantly greater than the distance between the middle finger crease 24 and the proximal finger crease 25 The specific distance dimensions are as follows:

[0026] Please see Figure 5 To achieve an anthropomorphic motion trajectory, the key lies in designing the number of corrugated segments at each joint. Under the same air pressure, the more corrugated segments, the larger the contraction and bending angle. In this embodiment, the ratio of the joint bending angles of the dexterous fingers when the human hand is grasping without load is set as follows: metacarpophalangeal joint: proximal interphalangeal joint: distal interphalangeal joint = 6:8:7 (MCP:PIP:DIP = 6:8:7). Based on ergonomic measurement data and the total bending angle of the three joints as constraints, the number of corrugated segments corresponding to the bending angle requirements is matched. For example, in this design, a 2mm pitch corrugated segment is selected as the actuator for joint bending. The number of corrugated segments is set to 6 at the metacarpophalangeal joint, 8 at the proximal interphalangeal joint, and 7 at the distal interphalangeal joint. The specific number can be modified according to the corrugated segment pitch and joint length.

[0027] Example 2 Please see Figure 7 and Figure 8 This embodiment provides a rigid-flexible coupled pneumatic humanoid dexterous hand, including a palm structure and five rigid-flexible coupled pneumatic humanoid dexterous fingers as described above; the palm structure includes a hand plate mechanism 26, on which five mounting notches are provided for mounting the five dexterous fingers respectively; it also includes a flexible palm patch 12 coupled to the palm side of the hand plate mechanism.

[0028] Specifically, the plane of the mounting notch for the four fingers (excluding the thumb) forms an angle with the main plane of the hand mechanism. This angle matches the physiological angle between the proximal phalanx of the corresponding finger and the palm plane in a naturally relaxed state. The plane of the mounting notch for the thumb forms a rotation angle with the main plane of the hand mechanism. This rotation angle matches the opposing posture of the thumb when the hand is naturally relaxed. At the same time, a crescent groove is provided on the inner side of the notch to provide passive movement space for the metacarpophalangeal joint of the dexterous thumb, enabling it to achieve spatial rotational movement that conforms to human physiological characteristics and improve the flexibility of palm gripping.

[0029] Specifically, the five dexterous fingers include the dexterous thumb 15, the dexterous index finger 16, the dexterous middle finger 17, the dexterous ring finger 18, and the dexterous little finger 19. The size and joint length ratio of each finger are designed based on the anatomical data of the corresponding human fingers.

[0030] Specifically, multiple flexible palm pads 12 are attached to the palm side of the hand mechanism 21. The multiple flexible palm pads 12 are made of highly elastic silicone and are respectively set as biomimetic structures to match the palm pad 12-1, the hypothenar pad 12-2, and the thenar pad 12-3. This can significantly enhance the contact area and gripping friction between the dexterous hand and the object being grasped, and at the same time, significantly improve the wrapping performance of irregular objects through flexible deformation.

[0031] Specifically, the back of the hand shell 13 is detachably integrated with the hand plate mechanism 21, which not only protects the internal components but also makes the overall appearance closer to the contour of the human hand. The fingers converge through preset channels to the airway outlet 14 located on the palm structure and are led out uniformly, which optimizes the tube layout while improving the overall aesthetics and structural integration of the dexterous hand.

[0032] In summary, the rigid-flexible coupling pneumatic anthropomorphic dexterous finger and hand of the present invention, with its rigid-flexible coupling structure and pneumatic drive scheme, can meet the dual requirements of "lightweight drive" and "high load-bearing grip". It is highly human-like in appearance, movement and function, and has good practical value and broad application prospects.

[0033] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements 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 rigid-flexible coupled pneumatic anthropomorphic dexterous finger, characterized in that: The device includes a segmented bellows actuator (1), a rigid cover plate (2), a rigid base plate (3), a flexible fingertip patch (4), and a unidirectional stretchable fabric (10). The straight section of the segmented bellows actuator (1) is clamped and fixed between the rigid cover plate (2) and the rigid base plate (3). The bellows section of the segmented bellows actuator (1) is arranged at the joint corresponding to the dexterous finger. Adjacent rigid base plates (3) are hinged together. The unidirectional stretchable fabric (10) is coupled to the back side of the rigid base plate (3). The unidirectional stretchable fabric (10) is stretchable along the axial direction of the finger but not stretchable along the radial direction of the finger. The flexible fingertip patch (4) is coupled to the contact side of the rigid base plate (3).

2. The rigid-flexible coupled pneumatic anthropomorphic dexterous finger as described in claim 1, characterized in that: The overall dimensions and length ratios of the dexterous fingers are designed in anthropomorphic fashion based on human finger anatomy data, and the crest radius of the corrugated pipe section is smaller than the cross-sectional radius of the corresponding human finger part.

3. The rigid-flexible coupled pneumatic anthropomorphic dexterous finger as described in claim 1, characterized in that: The bellows segments corresponding to the metacarpophalangeal joints, proximal interphalangeal joints, and distal interphalangeal joints of the dexterous fingers have different wave numbers, so that the bending angle ratio of each joint under air pressure drives conforms to the preset bending angle ratio of human hand joints.

4. The rigid-flexible coupled pneumatic anthropomorphic dexterous finger as described in claim 3, characterized in that: The ratio of the joint bending angle of the dexterous fingers is set as follows: metacarpophalangeal joint: proximal interphalangeal joint: distal interphalangeal joint = 6:8:

7.

5. The rigid-flexible coupled pneumatic anthropomorphic dexterous finger as described in claim 1, characterized in that: The adjacent rigid base plate (3) is hinged by bearing (8) and pin (9); the straight pipe section of the segmented bellows actuator (1) is rigidly coupled and fixed by screw (6) and nut (7).

6. A rigid-flexible coupled pneumatic anthropomorphic dexterous hand, characterized in that: It includes a palm structure and five rigid-flexible coupled pneumatic anthropomorphic dexterous fingers as described in any one of claims 1-5; the palm structure includes a hand plate mechanism (26), which has five mounting notches for mounting the five dexterous fingers respectively; it also includes a flexible palm patch (12) coupled to the palm side of the hand plate mechanism (26).

7. The rigid-flexible coupled pneumatic anthropomorphic dexterous finger as described in claim 6, characterized in that: The plane of the mounting notch for installing the four fingers other than the thumb forms an angle with the main plane of the hand mechanism. This angle matches the physiological angle between the proximal phalanx of the corresponding finger and the palm plane when the human body is in a naturally relaxed state. The plane of the mounting notch for installing the thumb forms a rotation angle with the main plane of the hand mechanism. This rotation angle matches the opposing palm posture of the thumb when the human hand is in a naturally relaxed state, and a crescent groove is provided on the inner side of the notch.

8. A rigid-flexible coupled pneumatic anthropomorphic dexterous finger as described in claim 6, characterized in that: Multiple flexible palm patches (12) are made of highly elastic silicone and are respectively set as biomimetic structures that match the palm pad (12-1), hypothenar pad (12-2), and thenar pad (12-3).

9. A rigid-flexible coupled pneumatic anthropomorphic dexterous finger as described in claim 6, characterized in that: The five dexterous fingers include the dexterous thumb (15), dexterous index finger (16), dexterous middle finger (17), dexterous ring finger (18), and dexterous little finger (19). The size and phalanx length ratio of each finger are designed based on the anatomical data of the corresponding human fingers.

10. A rigid-flexible coupled pneumatic anthropomorphic dexterous finger as described in claim 6, characterized in that: It also includes a back shell (13) that is detachably connected to the hand plate mechanism (26); the air ducts (11) of each of the dexterous fingers converge through a preset channel to the air duct outlet (14) provided on the palm structure.

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