A palm reconfigurable multi-fingered dexterous hand

Abstract

The application relates to a palm-reconfigurable multi-fingered dexterous hand, which comprises a fixed base, PRRR connecting branch chains, a spatial eight-link closed-loop reconfigurable palm mechanism, a driving motor installed in the base, a palm reconfiguration driving motor used for coordinately driving the moving pairs of the PRRR connecting branch chains to move along corresponding guide rails, and finger driving motors used for respectively driving four under-actuated fingers to complete bending and grabbing actions. The reconfigurable palm is a spatial two-degree-of-freedom eight-link single closed-loop mechanism formed by connecting eight connecting rods at the heads and tails, and the axes of the eight rotating pairs are not coplanar; branch chain connecting nodes and finger mounting nodes are alternately arranged along the eight-link closed loop. Four PRRR connecting branch chains are connected with the base and four branch chain connecting nodes respectively, the spatial eight-link closed-loop mechanism is driven to generate configuration changes by changing the positions of the moving pairs, so that the distance, direction and opposite relationship among the finger mounting nodes are adjusted. The application can form different palm configurations such as contraction, expansion, symmetry and opposition, and the grasping adaptability to objects with different sizes and shapes is improved.

Description

Technical Field

[0001] This invention belongs to the field of parallel robots, specifically relating to a multi-finger dexterous hand with reconfigurable palm. Background Technology

[0002] As the final link in the interaction between robots and their environment, dexterous hands have shown great application potential in multiple fields. Early dexterous hands mostly employed serial mechanisms. To improve structural stiffness, operational stability, and task adaptability, researchers are continuously exploring the use of parallel mechanisms in dexterous hand design. Compared to serial hands, parallel hands, through their closed-loop structure, can improve stiffness, force transmission capacity, and load-bearing capacity, while reducing the gradual accumulation of joint errors. Traditional dexterous hands often employ a rigid, fixed palm structure, with the position and orientation of the finger roots remaining unchanged. Grasping is primarily achieved through finger joint movements, which limits their ability to adapt to objects of different shapes and sizes. Introducing reconfigurable designs allows for relative movement of the internal components of the palm, thereby altering the distance and direction between the finger roots and expanding the dexterous hand's configurational adjustment capabilities. Current research trends indicate that the combination of parallel mechanisms and variable-structure mechanisms in dexterous hand design shows high potential. This combination can create novel dexterous hands that possess both structural stability and configurational adjustability. Summary of the Invention

[0003] The purpose of this invention is to provide a reconfigurable multi-finger dexterous hand with a four-finger structure. It can change the installation position and gripping direction of the four fingers through the movement of the spatial eight-bar closed-loop palm and the four PRRR connecting chains, and use tendon ropes to drive the fingers to complete the grasping. It has the characteristics of adjustable grasping range, diverse grasping functions, and variable grasping configuration.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] This invention provides a reconfigurable multi-finger dexterous hand with a four-finger structure, including a base, four identical PRRR connecting chains, a spatial eight-bar closed-loop hand mechanism, and four identical fingers.

[0006] The base has four guide rails at its top, spaced 90 degrees apart. A corresponding slider is placed above each guide rail, guiding it to move linearly in a specified direction. Each slider is equipped with a rotating joint connector. Four PRRR connecting chains connect one end to the corresponding rotating joint connector and the other end to an eight-bar closed-loop hand mechanism. The base contains eight drive motors: four for hand reconstruction and four for finger drive motors. The four hand reconstruction drive motors are connected to the corresponding PRRR connecting chains. By driving the movement of the four PRRR connecting chains, the hand reconstruction drive motors control the overall shape change of the reconstructable hand. The finger drive motors rotate to contract the drive tendons on the fingers, causing them to bend.

[0007] The spatial eight-bar closed-loop hand mechanism is connected to the base via four PRRR connecting chains, forming a spatial two-degree-of-freedom eight-bar single closed-loop mechanism. The spatial eight-bar closed-loop mechanism consists of eight links connected end-to-end via eight revolute joints to form a closed loop. The axes of the eight revolute joints are not coplanar, allowing the mechanism to maintain the closed-loop connection while undergoing spatial configuration changes. Four branch connection nodes and four finger mounting nodes are alternately arranged along the eight-bar closed loop. Each link is connected to one branch connection node and one finger mounting node at its two ends. The four branch connection nodes are connected to the four PRRR connecting chains, and the four finger mounting nodes are used to mount four fingers. Under the constraints of its link lengths, the included angle of the revolute joint axes, and symmetry, the spatial eight-bar closed-loop mechanism has two configurational degrees of freedom. Under the support, drive, and constraint of the PRRR connecting chains, it undergoes configuration changes, which in turn alter the relative distance and spatial posture between the four finger mounting nodes, thereby adjusting the grasping range of the hand and the opposition relationship between the fingers.

[0008] In this invention, each PRRR kinematic branch consists of a revolute joint P and a first revolute joint. Second rotating joint and the third rotating joint The first rotary joint is composed of a guide rail mounted on the base and a slider that can move along the guide rail, connected in sequence. The first rotary joint is connected to the slider. With the second rotating pair The two are connected by a first chain link, and the second rotating joint With the third rotating joint The third rotating joint is connected by a second branch link. Connected to the corresponding branch connection node of the spatial eight-bar closed-loop mechanism; the first revolute joint With the second rotating pair The axes are parallel, and the second revolute joint With the third rotating joint The axis is perpendicular, and the prismatic joint P changes the position of the branch on the base, the first revolute joint Second rotating joint and the third rotating joint It enables the branch ends to change with the position and direction of the support node, providing support, drive and motion constraints for the reconfigurable hand without restricting the predetermined configuration changes of the spatial eight-bar closed-loop mechanism.

[0009] In this invention, the four fingers are respectively installed on the four finger mounting nodes of the spatial eight-bar closed-loop mechanism; each finger consists of a finger mounting end, a proximal phalanx, a distal phalanx, a driving tendon cord, and a return spring. The proximal phalanx is connected to the finger mounting end, and the distal phalanx is connected to the proximal phalanx via revolute joints; each finger is driven by a corresponding cord drive mechanism. One end of the tendon cord of the cord drive mechanism is connected to the corresponding drive motor winding wheel, and the other end is arranged along the tendon cord guide mechanism in each phalanx and finally fixed at the fingertip position; when the drive motor winding wheel rotates to one side, the driving tendon cord contracts, causing each phalanx to bend, producing a grasping-like motion; when the drive motor winding wheel rotates to the other side, the driving tendon cord is released, and the return spring drives the phalanx to return to its initial position.

[0010] In this invention, a battery and a single-chip microcontroller are placed inside the base. The battery is connected to the single-chip microcontroller, and the single-chip microcontroller is connected to eight drive motors respectively through DuPont wires, so that the eight drive motors can be controlled.

[0011] The working principle of this invention is as follows:

[0012] When the reconfigurable multi-finger dexterous hand grasps, a single-chip microcontroller inside the base coordinates and controls the four palm reconstruction drive motors and the four finger drive motors. First, the four palm reconstruction drive motors are controlled to move, causing the sliders at the bottom of the four PRRR connecting chains to move linearly along their corresponding guide rails. The positional change of the prismatic joint P is transmitted to the four connecting nodes of the spatial eight-bar closed-loop mechanism through three revolute joints in each chain. Then, the spatial eight-bar closed-loop mechanism undergoes a configuration change under the closed-loop constraint, driving the movement of the four finger mounting nodes that are alternately positioned with it. By coordinating and controlling the movement of the four connecting chains, the spatial eight-bar closed-loop mechanism can form different configurations such as contraction, expansion, symmetry, or opposition, thereby adjusting the base spacing, mounting direction, and opposition relationship of the four fingers before the fingers close. After the palm configuration adjustment is completed, the four finger drive motors rotate respectively, pulling the fingers into a bent posture. After the fingers contact the object, the knuckles undergo adaptive bending under the combined action of the tendons and the object's constraints, forming a stable grasp.

[0013] The beneficial effects of this invention are as follows: By coordinating the drive of the spatial eight-bar closed-loop palm mechanism through four PRRR connecting branches, the linkage adjustment of finger installation position, spacing, and opposition relationship is achieved, enabling the dexterous hand to form various grasping configurations such as contraction, expansion, symmetry, and opposition, expanding the grasping range and improving adaptability to objects of different sizes and shapes. The spatial closed-loop palm combined with the multi-branch support structure provides structural support for grasping while realizing changes in palm configuration. Each finger adopts an independently driven tendon-cord under-driven structure, allowing the knuckles to adaptively bend after contacting the object. Through palm configuration adjustment and finger envelope grasping, the flexibility and stability of grasping are improved, and a return spring is used to achieve finger reset after release.

[0014] This device features adjustable grasping range, diverse grasping functions, and varied grasping configurations. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention when a four-finger structure is used;

[0016] Figure 2 This is a schematic diagram of the fixed base structure of the present invention;

[0017] Figure 3 This is a schematic diagram of the spatial eight-bar closed-loop palm structure of the present invention;

[0018] Figure 4 This is a schematic diagram of the PRRR connection branch structure of the present invention;

[0019] Figure 5 This is a schematic diagram of the first finger structure of the present invention;

[0020] Figure 6 This is an exploded view of the fixed base assembly of the present invention;

[0021] Figure 7 This is an exploded view of the spatial eight-bar closed-loop palm assembly of the present invention;

[0022] Figure 8 This is a schematic diagram of the PRRR connection branch of the present invention.

[0023] Figure 9 This is an exploded view of the first finger component of the present invention.

[0024] The diagram is labeled as follows: 1 is the fixed base; 2, 3, 4, and 5 are the first, second, third, and fourth PRRR connecting chains, respectively; 6 is the spatial eight-bar closed-loop hand mechanism; 7 is the first finger; 8 is the second finger; 9 is the third finger; 10 is the fourth finger; 1-1, 1-2, 1-3, and 1-4 are the first, second, third, and fourth rotating joint connecting parts, respectively; 1-5, 1-6, 1-7, and 1-8 are the first, second, third, and fourth slider assemblies, respectively; 1-9, 1-10, 1-11, and 1-12 are the first, second, third, and fourth guide rails, respectively; and 1-13 is the base. Top plate, 1-14 is the main body of the first base, 1-15 is the main body of the second base, 1-16 is the lower base plate, 2-1, 2-2, 2-3, 2-4, 2-5, 2-6, 2-7, and 2-8 are the first, second, third, fourth, fifth, sixth, seventh, and eighth rods, respectively, 3-1 is the first connector, 3-2 is the second connector, 3-3 is the third connector, 4-1 is the fingertip, 4-2 is the first phalanx, 4-3 is the left half of the second phalanx, 4-4 is the first guide shaft, 4-5 is the second guide shaft, 4-6 is the right half of the second phalanx, and 4-7 is the metacarpophalangeal joint. Detailed Implementation

[0025] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention and do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] like Figure 1 As shown, the multi-finger dexterous hand of the present invention adopts a four-finger structure in this embodiment, including a fixed base 1, a first PRRR connecting branch 2, a second PRRR connecting branch 3, a third PRRR connecting branch 4, a fourth PRRR connecting branch 5, a spatial eight-bar closed-loop palm mechanism 6, a first finger 7, a second finger 8, a third finger 9, and a fourth finger 10; the first PRRR connecting branch 2, the second PRRR connecting branch 3, the third PRRR connecting branch 4, and the fourth PRRR connecting branch 5 have the same structure; the first PRRR connecting branch 2, the second PRRR connecting branch 3, the third PRRR connecting branch 4, and the fourth PRRR connecting branch 5 are arranged at a 90-degree interval between the base and the spatial eight-bar closed-loop palm mechanism; the first finger 7, the second finger 8, the third finger 9, and the fourth finger 10 have the same structure.

[0027] The base 1, as referred to Figure 2 and Figure 6The system includes a base top plate 1-13, a first base body 1-14, a second base body 1-15, and a base bottom plate 1-16. The first base body 1-14 is fixed above the second base body 1-15, and the bottom of the second base body 1-15 is fixed to the base bottom plate 1-16. The base top plate 1-13 is fixed above the first base body 1-14. A first guide rail 1-9, a second guide rail 1-10, a third guide rail 1-11, and a fourth guide rail 1-12 are mounted on the base top plate 1-13. The first guide rail 1-9 and the third guide rail 1-11 are arranged in the same direction, and the second guide rail 1-10 and the fourth guide rail 1-12 are arranged in the same direction. The first guide rail 1-9 and the third guide rail 1-11 are arranged perpendicular to the second guide rail 1-10 and the fourth guide rail 1-12. A first slider assembly 1-5 is arranged on the first guide rail 1-9, and the second guide rail... A second slider assembly 1-6 is arranged on 1-10, a third slider assembly 1-7 is arranged on the first guide rail 1-11, and a fourth slider assembly 1-8 is arranged on the fourth guide rail 1-10. A first rotary joint connector 1-1 is installed on the first slider assembly 1-5, a second rotary joint connector 1-2 is installed on the second slider assembly 1-6, a third rotary joint connector 1-3 is installed on the third slider assembly 1-7, and a fourth rotary joint connector 1-4 is installed on the fourth slider assembly 1-8. Eight drive motors are installed inside the base 1, four of which are palm reconstruction drive motors and the other four are finger drive motors. The palm reconstruction drive motors can control the overall shape change of the reconstructable palm by driving the movement of the four PRRR connecting branches. The finger drive motors rotate to cause the drive tendons on the fingers to contract, thereby causing the fingers to bend.

[0028] The spatial eight-bar closed-loop palm mechanism 6, as referred to Figure 3 and Figure 7 The mechanism consists of a first link 2-1, a second link 2-2, a third link 2-3, a fourth link 2-4, a fifth link 2-5, a sixth link 2-6, a seventh link 2-7, and an eighth link 2-8. These links are connected end-to-end via revolute joints to form a spatial eight-link closed loop. The axes of the eight revolute joints are not coplanar, allowing the mechanism to maintain the closed loop connection while undergoing spatial configuration changes. Four branch connection nodes and four finger mounting nodes are alternately arranged along the eight-link closed loop. Each link is connected to one branch connection node and one finger mounting node at each end. The connection points of adjacent links also serve as finger mounting points and branch mounting points. The four branch connection nodes... Install nodes with four fingers Alternating along the closed loop, the branch connection nodes are respectively connected to the first PRRR connection branch 2, the second PRRR connection branch 3, the third PRRR connection branch 4, and the fourth PRRR connection branch 5, and the finger mounting nodes are respectively connected to the first finger 7, the second finger 8, the third finger 9, and the fourth finger 10.

[0029] The first PRRR connection branch 2, refer to Figure 4 and Figure 8 (The second PRRR connecting branch 3, the third PRRR connecting branch 4, and the fourth PRRR connecting branch 5 have the same structure as the first PRRR connecting branch 2), including a first connector 3-1, a second connector 3-2, and a third connector 3-3; the upper end of the first connector 3-1 is a revolute joint, which connects to the branch connection node of the spatial eight-bar closed-loop palm mechanism. Relying on rotating pairs Connected; the first connector 3-1 and the second connector 3-2 are connected by a rotating joint. Connection; the second connecting member 3-2 and the third connecting member 3-3 are connected by a rotating joint. The lower end of the third connector 3-3 is connected to the first slider assembly 1-5, the second slider assembly 1-6, the third slider assembly 1-7, and the fourth slider assembly 1-8 of the fixed base 1. When the first slider assembly 1-5, the second slider assembly 1-6, the third slider assembly 1-7, and the fourth slider assembly 1-8 slide along the first guide rail 1-9, the second guide rail 1-10, the third guide rail 1-11, and the fourth guide rail 1-12, they drive the first PRRR connecting branch 2, the second PRRR connecting branch 3, the third PRRR connecting branch 4, and the fourth PRRR connecting branch 5 to move, thereby changing the position of the first connector 3-1 at the end of the branch, indirectly affecting the movement of the spatial eight-bar closed-loop palm mechanism 6.

[0030] The first finger 7, as referenced Figure 5 and Figure 9 (The second finger 8, the third finger 9, and the fourth finger 10 are identical to the first finger 7), comprising a fingertip 4-1, a first phalanx 4-2, a second phalanx, and a metacarpophalangeal joint 4-7; the second phalanx is composed of the left half 4-3, a guide shaft 4-4, a guide shaft 4-5, and the right half 4-6; each phalanx is connected by a revolute joint to achieve finger bending; the metacarpophalangeal joint 4-7 is connected to the finger mounting node of the spatial eight-bar closed-loop hand mechanism 6. Connected via a rotating joint.

[0031] The above description is merely a preferred embodiment of the present invention, and these embodiments are intended to aid in understanding the present invention, rather than constituting any limitation thereof. For those skilled in the art, modifications, combinations, or equivalent substitutions can be made to the above embodiments without departing from the core ideas and technical solutions of the present invention, and such modifications, combinations, or equivalent substitutions should all be considered to be included within the protection scope of the present invention.

Claims

1. A multi-finger dexterous hand with reconfigurable palm, characterized in that... It adopts a four-finger structure, including a base, four identical PRRR connecting chains, a spatial eight-bar closed-loop palm mechanism, and four identical fingers. The base has four guide rails at its top, spaced 90 degrees apart. A corresponding slider is placed above each guide rail, guiding it to move linearly in a specified direction. Each slider is equipped with a rotating joint connector. Four PRRR connecting chains connect one end to the corresponding rotating joint connector and the other end to an eight-bar closed-loop hand mechanism. The base contains eight drive motors: four for hand reconstruction and four for finger drive motors. The four hand reconstruction drive motors are connected to the corresponding PRRR connecting chains. By driving the movement of the four PRRR connecting chains, the hand reconstruction drive motors control the overall shape change of the reconstructable hand. The finger drive motors rotate to contract the drive tendons on the fingers, causing them to bend. The spatial eight-bar closed-loop hand mechanism is connected to the base via four PRRR connecting chains, forming a spatial two-degree-of-freedom eight-bar single closed-loop mechanism. The spatial eight-bar closed-loop hand mechanism consists of eight links connected end-to-end via eight revolute joints to form a closed loop. The axes of the eight revolute joints are not coplanar, allowing the spatial eight-bar closed-loop hand mechanism to undergo spatial configuration changes while maintaining the closed-loop connection. Four branch connection nodes and four finger mounting nodes are alternately arranged along the eight-bar closed loop. Each link is connected to one branch connection node and one finger mounting node at its two ends. The four branch connection nodes are respectively connected to the four PRRR connecting chains, and the four finger mounting nodes are used to mount four fingers. Under the constraints of its link lengths, the included angle of the revolute joint axes, and symmetry, the spatial eight-bar closed-loop hand mechanism has two configurational degrees of freedom. Under the support, drive, and constraint of the PRRR connecting chains, it undergoes configurational changes, which in turn alter the relative distance and spatial posture between the four finger mounting nodes, thereby adjusting the grasping range of the hand and the opposition relationship between the fingers.

2. A reconfigurable multi-finger dexterous hand according to claim 1, characterized in that... Each PRRR kinematic chain consists of a revolute joint P and a first revolute joint. Second rotating joint and the third rotating joint The first rotary joint is composed of a guide rail mounted on the base and a slider that can move along the guide rail, connected in sequence. The first rotary joint is connected to the slider. With the second revolute joint The two are connected by a first chain link and a second rotating joint. With the third rotating joint The third rotating joint is connected by a second branch link. Connected to the corresponding branch connection node of the spatial eight-bar closed-loop mechanism; the first revolute joint With the second revolute joint The axes are parallel, and the second revolute joint With the third rotating joint The axis is perpendicular, and the prismatic joint P changes the position of the branch on the base, the first revolute joint Second rotating joint and the third rotating joint It enables the branch ends to change with the position and direction of the support node, providing support, drive and motion constraints for the reconfigurable hand without restricting the predetermined configuration changes of the spatial eight-bar closed-loop mechanism.

3. A reconfigurable multi-finger dexterous hand according to claim 1, characterized in that... The four fingers are respectively installed on the four finger mounting nodes of the spatial eight-bar closed-loop mechanism; each finger consists of a finger mounting end, a proximal phalanx, a distal phalanx, a driving tendon cord, and a return spring. The proximal phalanx is connected to the finger mounting end, and the distal phalanx is connected to the proximal phalanx via revolute joints; each finger is driven by a corresponding cord drive mechanism. One end of the tendon cord of the cord drive mechanism is connected to the corresponding drive motor winding wheel, and the other end is arranged along the tendon cord guide mechanism in each phalanx and finally fixed at the fingertip position; when the drive motor winding wheel rotates to one side, the driving tendon cord contracts, causing each phalanx to bend, producing a grasping-like motion; when the drive motor winding wheel rotates to the other side, the driving tendon cord is released, and the return spring drives the phalanx to return to its initial position.

4. A reconfigurable multi-finger dexterous hand according to claim 1, characterized in that... The base houses a battery and a microcontroller. The battery is connected to the microcontroller, which is then connected to eight drive motors via DuPont wires, thus enabling control of the eight drive motors.

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