A flexible continuum dexterous hand

Abstract

This invention relates to a flexible, continuous dexterous hand, comprising a thumb, index finger, middle finger, ring finger, little finger, and palm. The index finger has a first and a second nickel-titanium alloy rod serving as internal supports, with tendon cords acting as the transmission mechanism. When the motor rotates, the tendon cords contract or extend, causing the index finger to bend or extend. The thumb, index finger, middle finger, ring finger, and little finger are driven by the same principle. The palm opens and closes by lateral movement of the index finger, ring finger, and little finger driven by a first servo motor. The thumb independently lateralizes by lateral movement driven by a second servo motor. This invention uses a single motor to drive the tendon cords to achieve finger bending, and two servo motors, respectively, via linkage mechanisms, to achieve multi-finger coordinated lateral movement and independent thumb lateral movement. This simplifies the system architecture while maintaining high integration, compliant grasping ability, and humanoid movement patterns.

Description

Technical Field

[0001] This application belongs to the field of robot bionics and environmental interaction technology, specifically relating to a flexible continuum dexterous hand. Background Technology

[0002] As a key end effector for robot interaction, the development level of the robot's dexterous hand directly affects the robot's operational performance and application scope. With the continuous growth in demand for precision operation and compliant grasping in fields such as industrial manufacturing, healthcare, and special operations, traditional dexterous hands have long relied on rigid knuckles and redundant multi-motor layouts in terms of structural form and drive method. This has resulted in large system size, complex control, and high cost. In terms of grasping adaptability, the rigid knuckle structure lacks the ability to passively conform to the shape of irregular objects, which can easily cause stress concentration or grasping failure.

[0003] Currently, the existing humanoid dexterous hands have the following main defects and shortcomings: 1. Rigid finger structure, lacking the ability to passively adapt to complex shapes. Existing dexterous hand fingers mostly employ a rigid joint structure composed of rigid linkages and rotating joints, with each joint driven to rotate by multiple motors or tendon cables. When grasping irregular or fragile objects, this type of rigid structure has difficulty conforming to the object's surface through its own deformation, resulting in fewer contact points and poor grasping stability.

[0004] The patent application with publication number CN222308872U, entitled "A Dexterous Hand with Modular Fingers," describes a humanoid five-fingered hand with modular fingers. The fingers have a continuous structure, but the design still uses a rigid skeleton and a constraint disc to drive the steel wire to achieve bending. The fingers as a whole lack continuous flexible deformation capabilities and cannot achieve passive adhesion and large-area envelopment similar to biological tissues during the grasping process.

[0005] 2. The chord drive transmission ratio is fixed, lacking the ability to adapt to sequential bending. Existing chord-driven dexterous hands mostly employ a single-rod direct traction method for each phalanx. The chord pulls each phalanx synchronously with a fixed transmission ratio. Once the proximal phalanx contacts an object, it restricts the continued movement of the distal phalanx, lacking sequential bending adaptive capability and failing to achieve passive fitting and enveloping grasping based on the object's shape during the grasping process. Patent publication CN121200045A, entitled "A Single-Driven Chord-Driven Robotic Dexterous Hand Finger and Method," uses a single motor to drive the chord to achieve finger bending, but the phalanx remains a rigid structure. The chord drives each phalanx to rotate synchronously with a fixed transmission ratio, failing to achieve the sequential coupling grasping function where the distal phalanx continues to bend when the proximal end is obstructed.

[0006] 3. The separate driving mechanisms for bending and lateral swaying motions make coordinated control difficult. Currently, solutions that enable dexterous hands to achieve two degrees of freedom—flexion and lateral swing—generally require two independent drive components to control the bending and lateral swing movements respectively. The transmission methods are mostly complex multi-link spatial mechanisms or dual-motor systems, which are structurally complex, have poor reliability, and make it difficult to achieve orderly timing coordination and motion decoupling between the bending and lateral swing movements.

[0007] The patent with publication number CN119567299B, entitled "A Dexterous Hand Finger, Dexterous Hand and Robot", describes a dexterous hand finger that includes a lateral swing assembly, a first phalanx, a linkage assembly, a tendon cord, and multiple sets of drive assemblies. The finger achieves three degrees of freedom of movement through a hybrid transmission of the linkage assembly and tendon cord. However, bending and lateral swinging need to be controlled by two independent sets of drive assemblies, which significantly increases the structural complexity and volume of the dexterous hand finger. Summary of the Invention

[0008] The purpose of this application is to overcome the shortcomings of the prior art and provide a flexible continuum dexterous hand. It adopts a flexible continuum structure composed of a nickel-titanium alloy rod and a flexible shell to replace the traditional rigid knuckles. A single motor drives the tendon rope to achieve finger bending, and two servos achieve multi-finger coordinated lateral swing and independent thumb lateral swing through a linkage mechanism. While simplifying the system architecture, it also takes into account high integration, compliant grasping ability and humanoid movement mode.

[0009] The technical problem solved by this application is achieved through the following technical solution: A flexible continuum dexterous hand includes a thumb, index finger, middle finger, ring finger, little finger, and palm. The index finger includes a fingertip cap, a flexible continuum shell, a cover, an index finger frame, a motor, a first nickel-titanium alloy rod, a second nickel-titanium alloy rod, a tendon cord, and a winding reel. The end of the motor is connected to the tendon cord, and the two ends of the tendon cord are flexibly supported and connected to the first and second nickel-titanium alloy rods. The tendon cord, the first nickel-titanium alloy rod, and the second nickel-titanium alloy rod are all fixed to the winding reel. The index finger frame and cover are provided outside the motor. The flexible continuum shell is provided outside the tendon cord, the first nickel-titanium alloy rod, and the second nickel-titanium alloy rod. The top ends of the tendon cord, the first nickel-titanium alloy rod, and the second nickel-titanium alloy rod are all connected to the fingertip cap. The structure of the thumb, middle finger, ring finger, and little finger is the same as that of the index finger; The palm is connected to the index finger, ring finger, and little finger via a linkage mechanism, enabling the palm to open and close by lateral movement of the index finger, ring finger, and little finger.

[0010] Moreover, when the motor rotates in the forward direction, the tendon contracts, and the flexible continuum shell is stretched and the index finger bends; when the motor rotates in the reverse direction, the index finger extends; the driving principle of the thumb, index finger, middle finger, ring finger and little finger is the same.

[0011] Furthermore, the linkage mechanism includes a first bearing, a first link, a second link, a third link, a first servo, a second bearing, a ring finger frame, a little finger frame, a third bearing, and a fourth link; the first servo is connected to the third link, the right side of the third link is connected to the first link and then to the index finger frame and fixed by the first bearing; the left side of the third link is connected to the ring finger frame and the fourth link, the fourth link is connected to the little finger frame and fixed by the third bearing, and the ring finger frame is fixed by the second bearing.

[0012] Moreover, when the first servo rotates forward, it drives the index finger to swing to the right, and at the same time drives the ring finger and little finger to swing to the left, thus opening the palm; when the first servo rotates in the reverse direction, the index finger swings to the left, and the ring finger and little finger swing to the right, thus closing the palm.

[0013] Furthermore, the palm is connected to the thumb via a second servo motor to enable independent lateral movement of the thumb. When the second servo motor rotates forward, the thumb swings inward toward the palm; when the second servo motor rotates in reverse, the thumb swings outward toward the palm.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses a nickel-titanium alloy rod and a flexible continuum shell to form a continuous deformable body, replacing the traditional rigid multi-joint knuckles. During the grasping process, the flexible continuum can passively conform to the surface of irregularly shaped objects, achieving large-area enveloping contact and compliant grasping.

[0015] 2. This invention uses a single motor to drive the tendon rope to uniformly stretch the flexible shell, enabling continuous bending of the fingers. Only five motors are needed to independently drive the five fingers of the entire hand, resulting in a compact structure and simple control.

[0016] 3. This invention uses a single servo motor to drive the coordinated lateral swing of the index, ring, and little fingers through a linkage mechanism, while another servo motor drives the thumb to independently face the palm, decoupling the bending and lateral swing functions, significantly reducing structural complexity and conforming to the natural movement pattern of the human hand. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the dexterous hand of the present invention; Figure 2 This is a schematic diagram of the internal structure of the dexterous hand of the present invention; Figure 3 This is a schematic diagram of the structure of the index finger of the present invention; Figure 4 This is another structural schematic diagram of the index finger of the present invention; Figure 5 This is a schematic diagram of the driving structure of the palm in this invention.

[0018] Explanation of reference numerals in the attached figures 1. Thumb; 2. Index finger; 3. Middle finger; 4. Ring finger; 5. Little finger; 6. Palm; 1-1, fingertip cap; 2-2, flexible continuous shell; 2-3, cover; 2-4, index finger frame; 2-5, motor; 2-6, first nickel-titanium alloy rod; 2-7, second nickel-titanium alloy rod; 2-8, tendon rope; 2-9, winding reel; 6-1, First bearing; 6-2, First link; 6-3, Second link; 6-4, Third link; 6-5, First servo; 6-6, Second bearing; 6-7, Ring finger frame; 6-8, Little finger frame; 6-9, Third bearing; 6-10, Fourth link; 6-11, Second servo. Detailed Implementation

[0019] The present application will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present application.

[0020] like Figures 1-5 As shown, a flexible continuous dexterous hand is innovative in that it includes a thumb 1, index finger 2, middle finger 3, ring finger 4, little finger 5, and palm 6. Since the driving principles of thumb 1, index finger 2, middle finger 3, ring finger 4, and little finger 5 are the same, only the driving method of index finger 2 needs to be described. The index finger 2 includes a fingertip cover 2-1, a flexible continuous shell 2-2, a cover 2-3, an index finger frame 2-4, a motor 2-5, a first nickel-titanium alloy rod 2-6, a second nickel-titanium alloy rod 2-7, a tendon rope 2-8, and a winding reel 2-9. The hand 6 includes a first bearing 6-1, an index finger frame 2-4, a first link 6-2, a second link 6-3, a third link 6-4, a first servo motor 6-5, a second bearing 6-6, a ring finger frame 6-7, a little finger frame 6-8, a third bearing 6-9, a fourth link 6-10, and a second servo motor 6-11.

[0021] The palm 6 is an integral load-bearing structure with high structural strength and light weight. The front and back of the palm are outer shell structures. The palm undertakes the structural function of supporting the five fingers.

[0022] The thumb (1), index finger (2), middle finger (3), ring finger (4), and little finger (5) all share the same driving principle. Therefore, explaining the driving principle of the index finger (2) suffices to describe the driving mechanism of all five fingers. The index finger is driven by motor (2-5). The mechanical structure, from the palm (6) to the fingertip, consists of an index finger frame (2-4) connected to a cover (2-3), then to a flexible continuous shell (2-2), and finally covered by a fingertip cover (2-1). The driving principle is described inside the index finger (2), supported by a first nickel-titanium alloy rod (2-6) and a second nickel-titanium alloy rod (2-7), and transmitted via a tendon cord (2-8). All five fingers are fixed to a winding reel (2-9). When motor (2-5) rotates forward, tendon cord (2-8) contracts, and the flexible continuous shell (2-2) is stretched due to the applied force, allowing the index finger (2) to bend normally. When motor (2-5) rotates in the reverse direction, the index finger (2) can extend normally.

[0023] The palm 6 allows for lateral movement of the index finger 2, ring finger 4, and little finger 5, thereby opening and closing the entire palm. This function is driven by a first servo motor 6-5. The first servo motor 6-5 is connected to a third link 6-4, and then connected to the first link 6-2 on the right side, which is then connected to the index finger frame 2-4, fixed in position by a first bearing 6-1. The left side is connected to the third link 6-4, which is connected in one direction to the ring finger frame 6-7, fixed in position by a second bearing 6-6. The third link 6... -4 Connects to the fourth link 6-10 in another direction, then connects to the little finger frame 6-8, which is fixed in position by the third bearing 6-9; when the first servo 6-5 rotates forward, the index finger 2 can swing to the right and the ring finger 4 and little finger 5 can swing to the left through the above mechanical structure, thus achieving the function of opening the palm; when the first servo 6-5 rotates in the opposite direction, the index finger 2 can swing to the left and the ring finger 4 and little finger 5 can swing to the right through the above mechanical structure, thus achieving the function of closing the palm.

[0024] The palm 6 can achieve the lateral swing of the thumb 1; this function is driven by the second servo motor 6-11; when the second servo motor 6-11 rotates in the forward direction, the thumb 1 swings inward towards the palm 6; when the second servo motor 6-11 rotates in the reverse direction, the thumb 1 swings outward towards the palm 6.

[0025] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A flexible continuum dexterous hand, characterized in that: The fingers include the thumb (1), index finger (2), middle finger (3), ring finger (4), little finger (5), and palm (6); the index finger (2) includes a fingertip cap (2-1), a flexible continuous shell (2-2), a cover (2-3), an index finger frame (2-4), a motor (2-5), a first nickel-titanium alloy rod (2-6), a second nickel-titanium alloy rod (2-7), a tendon cord (2-8), and a winding reel (2-9); the end of the motor (2-5) is connected to the tendon cord (2-8), and the two ends of the tendon cord (2-8) are flexibly supported and connected to the first nickel-titanium alloy rod (2-6) and the second nickel-titanium alloy rod (2-9). Titanium alloy rod (2-7), tendon cord (2-8), first nickel-titanium alloy rod (2-6) and second nickel-titanium alloy rod (2-7) are all fixed on the winding reel (2-9), the motor (2-5) is provided with an index finger frame (2-4) and a cover (2-3), the tendon cord (2-8), first nickel-titanium alloy rod (2-6) and second nickel-titanium alloy rod (2-7) are provided with a flexible continuous shell (2-2), and the top ends of the tendon cord (2-8), first nickel-titanium alloy rod (2-6) and second nickel-titanium alloy rod (2-7) are connected to the fingertip cover (2-1); The structure of the thumb (1), middle finger (3), ring finger (4) and little finger (5) is the same as that of the index finger (2); The palm (6) is connected to the index finger (2), ring finger (4) and little finger (5) through a linkage mechanism, so that the lateral swing of the index finger (2), ring finger (4) and little finger (5) completes the opening and closing of the palm.

2. The flexible continuum dexterous hand according to claim 1, characterized in that: When the motor (2-5) rotates in the forward direction, the tendon rope (2-8) contracts, the flexible continuum shell (2-2) is stretched, and the index finger (2) bends; when the motor (2-5) rotates in the reverse direction, the index finger (2) extends; the driving principle of the thumb (1), index finger (2), middle finger (3), ring finger (4), and little finger (5) is the same.

3. The flexible continuum dexterous hand according to claim 1, characterized in that: The linkage mechanism includes a first bearing (6-1), a first link (6-2), a second link (6-3), a third link (6-4), a first servo (6-5), a second bearing (6-6), a ring finger frame (6-7), a little finger frame (6-8), a third bearing (6-9), and a fourth link (6-10). The first servo (6-5) is connected to the third link (6-4). The right side of the third link (6-4) is connected to the first link (6-2) and then to the index finger frame (2-4), and is fixed by the first bearing (6-1). The left side of the third link (6-4) is connected to the ring finger frame (6-7) and the fourth link (6-10). The fourth link (6-10) is connected to the little finger frame (6-8) and is fixed by the third bearing (6-9). The ring finger frame (6-7) is fixed by the second bearing (6-6).

4. The flexible continuum dexterous hand according to claim 1, characterized in that: When the first servo motor (6-5) rotates in the forward direction, it drives the index finger (2) to swing to the right, and at the same time drives the ring finger (4) and little finger (5) to swing to the left, so as to open the palm; when the first servo motor (6-5) rotates in the reverse direction, the index finger (2) swings to the left, and the ring finger (4) and little finger (5) swing to the right, so as to close the palm.

5. The flexible continuum dexterous hand according to claim 1, characterized in that: The palm (6) is driven to the thumb (1) by the second servo motor (6-11) to achieve independent lateral swing of the thumb (1). When the second servo motor (6-11) rotates in the forward direction, the thumb (1) swings inward to the palm (6); when the second servo motor (6-11) rotates in the reverse direction, the thumb (1) swings outward to the palm (6).

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