Under-actuated finger unit and under-actuated dexterous manipulator

Abstract

The invention relates to the technical field of mechanical bionics, and discloses an under-actuated finger unit and an under-actuated dexterous hand, the under-actuated finger unit comprises a fixed end, a first phalanx, a second phalanx, a first joint, a second joint, a first rope and a driving rope; the fixed end, the first phalanx and the second phalanx are sequentially pivoted through the first joint and the second joint; one end of the first rope is fixed in the fixed end, firstly bypasses a first joint on the outer side surface of the back of the hand and then penetrates into the first phalanx, penetrates out of the first phalanx, firstly bypasses a second joint on the inner side surface of the palm and then penetrates into the second phalanx and is fixed; one end of the driving rope is connected with the palm inner side face of the first phalanx, and the other end is in transmission connection with the first power assembly and used for pulling the first phalanx to rotate around the first joint towards the palm inner side face under pulling of the first power assembly. A friction driving mode in a traditional under-actuated finger unit is abandoned, the pulling force of the driving rope drives the joints to extrude the rope to generate pulling force, friction force transmission is replaced with pulling force transmission, and accurate grabbing is achieved.

Description

Technical Field

[0001] This invention relates to the field of mechanical bionics, and in particular to an underactuated finger unit and an underactuated dexterous manipulator. Background Technology

[0002] As the core execution component of humanoid robots, the flexibility of bionic robotic hands is the core indicator for measuring their performance, and the degree of freedom is the key support for flexibility. Therefore, the development of dexterous hands with higher degrees of freedom has become the mainstream trend of technological development in the industry.

[0003] However, when existing bionic robotic arms increase their degrees of freedom to improve flexibility, they often require more drive devices, resulting in bulky robotic arm structures and increased mass. This not only limits their application in confined spaces but also increases the difficulty of operation due to excessive inertia.

[0004] Numerous attempts have been made in this area within the industry. For example, patent application CN120503236A discloses a 22-DOF dexterous hand. This solution utilizes rope (tendon cord) transmission combined with a multi-joint design to achieve multi-directional movement of the fingers, palm, and wrist. However, this solution uses a figure-eight rope wound around pulleys at the finger joints, with an external chain directly pulling the figure-eight rope. The joint rotation is driven by the friction between the figure-eight rope and the pulleys at the joints. The instability of this friction directly limits the upper limit of the manipulator's precision. When the load changes or the rope tension is insufficient, slippage can easily occur between the rope and the joint, leading to a significant increase in movement deviation. This deviation cannot be recovered through reset and is considered permanent, making it difficult for this solution to meet high-precision requirements.

[0005] Therefore, how to avoid slippage while ensuring driving accuracy has become an urgent technical problem to be solved. Summary of the Invention

[0006] The technical problem to be solved by this invention is: how to avoid slippage while ensuring driving accuracy.

[0007] To address the aforementioned technical problems, this invention provides an underactuated finger unit and an underactuated dexterous manipulator.

[0008] In a first aspect, the present invention provides an underactuated finger unit driven by a first power component. The underactuated finger unit includes a fixed end, a first phalanx, a second phalanx, a first joint, a second joint, a first rope, and a drive rope. The first end of the first phalanx is pivotally connected to the fixed end via the first joint. The first end of the second phalanx is pivotally connected to the second end of the first phalanx via the second joint. The first end of the first rope is fixed inside the fixed end. The first rope first passes around the first joint on the outer side of the back of the hand and then passes through the first phalanx. The first rope then passes out of the first phalanx and first passes around the second joint on the inner side of the palm and then passes through the second phalanx. The second end of the first rope is fixed inside the second phalanx. One end of the drive rope is connected to the inner side of the palm of the first phalanx, and the other end of the drive rope is connected to the first power component for transmission. The drive rope is used to pull the first phalanx around the first joint toward the inner side of the palm under the pull of the first power component.

[0009] In one embodiment, the underactuated finger unit is further driven by a reset assembly. The underactuated finger unit also includes a second rope and a reset cord. The first end of the second rope is fixed inside the fixed end. The second rope first passes around the first joint on the inner side of the palm and then enters the first phalanx. The second rope exits from the first phalanx and passes around the second joint on the outer side of the back of the hand before entering the second phalanx. The second end of the second rope is fixed inside the second phalanx. One end of the reset cord is connected to the outer side of the back of the hand of the first phalanx, and the other end of the reset cord is connected to the reset assembly. The reset cord is used to pull the first phalanx to rotate to the back side under the pull of the reset assembly.

[0010] In one embodiment, the reset component is a tension-type elastic element.

[0011] In one embodiment, the underactuated finger unit further includes a third phalanx, a third joint, a third cord, and a fourth cord; the first end of the third phalanx is pivotally connected to the second end of the second phalanx via the third joint; the first end of the third cord is fixed inside the first phalanx, the third cord first passes around the second joint on the outer side of the back of the hand and then enters the second phalanx, the third cord exits from the second phalanx and first passes around the third joint on the inner side of the palm and then enters the third phalanx, the second end of the third cord is fixed inside the third phalanx; the first end of the fourth cord is fixed inside the first phalanx, the fourth cord first passes around the second joint on the inner side of the palm and then enters the second phalanx, the fourth cord exits from the second phalanx and first passes around the third joint on the outer side of the back of the hand and then enters the third phalanx, the second end of the fourth cord is fixed inside the third phalanx.

[0012] In one embodiment, the first rope, the second rope, the third rope, or the fourth rope is an aramid rope.

[0013] In one embodiment, the first rope, the second rope, or the third rope is secured with screws.

[0014] In one embodiment, the underactuated finger unit is mounted on the palm body, which has a plurality of mounting surfaces and a second magnetic component on the mounting surfaces; the end face of the fixed end away from the first joint is provided with a first magnetic component, which attracts the second magnetic component; one of the mounting surfaces and the end face is provided with a protrusion and the other is provided with a concave portion, which corresponds to and engages with the concave portion.

[0015] In one embodiment, the first power component includes a servo motor and a servo disc. The servo motor is fixed to the palm body, and the other end of the drive rope is wrapped around the circumferential surface of the servo disc. The servo motor drives the servo disc to rotate, thereby pulling the second finger bone.

[0016] In one embodiment, the underactuated finger unit is further driven by a second power component, which drives a second gear; a first gear is fixed at the end of the fixed end away from the first joint, and the rotation plane of the first gear forms a preset angle with the rotation plane of any joint. The first gear is used to drive the underactuated finger unit to swing under the drive of the second gear.

[0017] A second aspect of the present invention provides an underactuated dexterous manipulator, comprising: a hand body having a plurality of first driving components on the hand body; and a plurality of underactuated finger units as provided in the first aspect of the present invention, wherein the first driving components correspond one-to-one with the underactuated finger units, and the first driving components are used to drive the underactuated finger units to bend.

[0018] Compared with the prior art, the underactuated finger unit and underactuated dexterous manipulator of this invention have the following advantages: The principle of grasping is as follows: A first rope is set up by crossing around the joint. When the driving rope pulls the first phalanx, the first phalanx rotates around the first joint toward the palm side (i.e., the inner side of the palm). At this time, the contact length between the first joint and the first rope on the side facing the back of the hand (i.e., the outer side of the back of the hand) gradually increases. Since the first end of the first rope is fixed, the first rope tends to be pulled out of the first joint under the action of the first joint. At this time, since the first rope is still wrapped around the inner side of the palm of the second joint, the contact length between the inner side of the palm of the second joint and the first rope gradually decreases. Therefore, the second joint does not resist the movement of the first rope toward the first joint. The pulling force generated at the first joint is smoothly transmitted to the second end and pulls the second phalanx to rotate around the second joint, thereby achieving grasping.

[0019] This invention abandons the friction-driven method in traditional underactuated finger units. The drive rope directly pulls the first phalanx. Although the first rope also uses a winding method, its two ends are fixed separately, fundamentally solving the problem of rope slippage. The tension of the drive rope is converted into the rotational force of the first phalanx. The first phalanx synchronously drives the first joint to squeeze the first rope towards the outer side of the back of the hand. Combined with the tension transmission characteristics of the first rope, it pulls the second phalanx to rotate towards the inner side of the palm in sync with the first phalanx, achieving precise gripping. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an underactuated finger unit as exemplarily shown in an embodiment of the present invention.

[0021] Figure 2 This is an exemplary embodiment of the present invention, showing an internal cross-sectional view of the second phalanx of an underactuated finger unit.

[0022] Figure 3 This is a schematic diagram illustrating an underactuated finger unit in an unbent state, as exemplarily shown in an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram illustrating the bending of an underactuated finger unit, as exemplarily shown in an embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram illustrating the fully bent state of an underactuated finger unit as exemplarily shown in an embodiment of the present invention.

[0025] Figure 6 This is a schematic diagram of the biphasic phalanges of an underactuated finger unit, as exemplarily shown in an embodiment of the present invention.

[0026] Figure 7 This is a schematic diagram illustrating the structure of an underactuated dexterous manipulator, as exemplarily shown in an embodiment of the present invention.

[0027] Figure 8 This is a schematic diagram illustrating the range of motion of four fingers of an underactuated dexterous manipulator, as exemplarily shown in an embodiment of the present invention.

[0028] Figure 9 This is a schematic diagram illustrating the range of motion of the thumb of an underactuated dexterous manipulator, as exemplarily shown in an embodiment of the present invention.

[0029] Figure 10 This is a schematic diagram illustrating the range of motion of the five fingers of an underactuated dexterous manipulator, as exemplarily shown in an embodiment of the present invention.

[0030] Figure 11 This is a schematic diagram illustrating the thumb and index finger of an underactuated dexterous manipulator as exemplarily shown in an embodiment of the present invention.

[0031] Figure 12 This is a schematic diagram illustrating the thumb and little finger of an underactuated dexterous manipulator as exemplarily shown in an embodiment of the present invention.

[0032] Figure 13 This is a schematic diagram illustrating an underactuated dexterous manipulator for holding a manual tool, as exemplarily shown in an embodiment of the present invention.

[0033] Figure 14 This is a schematic diagram illustrating an underactuated dexterous manipulator grasping an irregularly shaped object, as exemplarily shown in an embodiment of the present invention.

[0034] Figure label: 1. Underactuated dexterous manipulator; 10. Underactuated finger unit; 11. Hand body; 101. Fixed end; 102. Finger bone; 103. Joint; 104. Rope; 105. Drive rope; 106. Reset rope; 107. First magnetic component; 108. Screw; 111. First power component; 113. Reset component; 114. Second magnetic component; 115. Second power component; 1011. First gear; 1021. First finger bone; 1022. Second finger bone; 1023. Third finger bone; 1031. First joint; 1032. Second joint; 1033. Third joint; 1041. First rope; 1042. Second rope; 1043. Third rope; 1044. Fourth rope; 1111. Servo motor; 1112. Servo disc; 1151. Second gear. Detailed Implementation

[0035] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0036] It should be understood that although the terms first, second, third, etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, a first rope may also be referred to as a second rope, and similarly, a second rope may also be referred to as a first rope. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0037] Underactuation refers to a robot end effector having fewer actuators than joint degrees of freedom. In this invention, the first, second, and third phalanges correspond to the anatomical proximal phalanx (PP), middle phalanx (MP), and distal phalanx (DP), respectively. In this invention, each phalanx employs an exemplary additive manufacturing structure.

[0038] The first, second, and third joints correspond to the three anatomical joints DIP (Distal Interphalangeal joint), PIP (Proximal Interphalangeal joint), and MCP (Metacarpophalangeal joint). In this invention, each joint uses a bearing as an exemplary structure.

[0039] In this invention, for ease of understanding and description, "first rope, second rope, third rope, and fourth rope" are collectively referred to as "ropes", "first phalanx, second phalanx, and third phalanx" are collectively referred to as "phalanxes", and "first joint, second joint, and third joint" are collectively referred to as "joints".

[0040] As a core actuator in industrial and service robots, bionic robotic hands play an irreplaceable role in precision assembly, medical assistance, and hazardous environments due to their ability to simulate human hand movements. Their performance directly determines the robot's operational range and task completion quality. Dexterity is a core indicator for measuring the performance of bionic robotic hands, while degrees of freedom are the key support for dexterity. Therefore, developing dexterous hands with higher degrees of freedom has become a mainstream trend in industry technological development.

[0041] However, the development of existing bionic robotic arms faces a core bottleneck: on the one hand, when increasing the degree of freedom to improve flexibility, more drive devices are often required, resulting in a bulky robotic arm structure and increased mass, which not only limits its application in confined spaces but also increases the difficulty of operation due to excessive inertia; on the other hand, even if some solutions achieve a high degree of freedom design, their drive precision is still difficult to meet the requirements of precision operations.

[0042] To address these issues, numerous attempts have been made in the industry. For example, Chinese invention patent application CN120503236A discloses a 22-DOF dexterous hand. This solution achieves a breakthrough in flexibility through rope (tendon cord) transmission combined with a multi-joint design, enabling multi-directional movement of the fingers, palm, and wrist. However, the essence of this type of rope-driven solution relies on the friction between the rope and the pulleys at the joints to achieve joint rotation. The instability of friction directly limits the upper limit of the robot's precision: on the one hand, long-term friction can lead to rope wear and elastic deformation, thereby changing the transmission ratio and affecting positioning accuracy; on the other hand, when the load changes or the rope tension is insufficient, slippage is very likely to occur, resulting in a significant increase in motion execution deviation, making it difficult to meet the high-precision requirements of scenarios such as precision assembly and micro-operations.

[0043] Therefore, how to avoid slippage while ensuring driving accuracy has become a key technical problem that urgently needs to be solved in the field of bionic robotic arms.

[0044] like Figure 1 As shown, a preferred embodiment of the present invention provides an underactuated finger unit 10, which includes a fixed end 101, a first phalanx 1021, a second phalanx 1022, a first joint 1031, a second joint 1032, a first rope 1041, and a drive rope 105.

[0045] The first end of the first phalanx 1021 is pivotally connected to the fixed end 101 via the first joint 1031; the first end of the second phalanx 1022 is pivotally connected to the second end of the first phalanx 1021 via the second joint 1032; the first end of the first rope 1041 is fixed inside the fixed end 101; the first rope 1041 first passes around the first joint 1031 on the outer side of the back of the hand and then passes into the first phalanx 1021; the first rope 1041 exits from the first phalanx 1021 and first passes around the second joint 1032 on the inner side of the palm and then passes into the second phalanx 1022; the second end of the first rope 1041 is fixed inside the second phalanx 1022; one end of the drive rope 105 is connected to the inner side of the palm of the first phalanx 1021; the other end of the drive rope 105 is connected to the first power assembly 111 for transmission; the drive rope 105 is used to pull the first phalanx 1021 around the first joint 1031 toward the inner side of the palm under the pull of the first power assembly 111.

[0046] The first rope 1041 is set up by crossing and wrapping around the joint 103. When the drive rope 105 pulls the first phalanx 1021, the first phalanx 1021 rotates around the first joint 1031 towards the palm side (i.e., the inner side of the palm). At this time, the contact length between the side of the first joint 1031 facing the back of the hand (i.e., the outer side of the back of the hand) and the first rope 1041 gradually increases. Since the first end of the first rope 1041 is fixed, the first rope 1041, under the action of the first joint 1031, generates a force that pulls the first rope... The tendency of 1041 to be pulled out from the first joint 1031; at this time, since the first rope 1041 is still wrapped around the inner side of the palm of the second joint 1032, the contact length between the inner side of the palm of the second joint 1032 and the first rope 1041 gradually decreases. Therefore, the second joint 1032 will not resist the movement of the first rope 1041 towards the first joint 1031. The pulling force generated at the first joint 1031 is smoothly transmitted to the second end and pulls the second finger bone 1022 to rotate around the second joint 1032, thereby achieving a grip.

[0047] This invention abandons the friction-driven method in the traditional underactuated finger unit 10. The drive rope 105 directly pulls the first phalanx 1021. Although the first rope 1041 also uses a winding method, its two ends are fixed and it is not used to transmit frictional force, thus solving the problem of rope 104 slippage at its root. The tension of the drive rope 105 is converted into the rotational force of the first phalanx 1021. The first phalanx 1021 simultaneously drives the first joint 1031 to press the first rope 1041 towards the outer side of the back of the hand. With the tension transmission characteristics of the first rope 1041, the second phalanx 1022 is pulled to rotate towards the inner side of the palm in sync with the first phalanx 1021. The tension transmission replaces the friction transmission, and the transmission characteristics of the rope 104 are utilized to achieve precise gripping.

[0048] For example, the underactuated finger unit 10 can be mounted on the palm body 11, on which the first power assembly 111 is mounted.

[0049] Furthermore, in a further embodiment of the present invention, the underactuated finger unit 10 can also be driven by a reset assembly 113, including a second rope 1042 and a reset rope 106.

[0050] The first end of the second rope 1042 is fixed inside the fixed end 101. The second rope 1042 first passes around the first joint 1031 on the inner side of the palm and then passes through the first phalanx 1021. The second rope 1042 passes out from the first phalanx 1021 and passes around the second joint 1032 on the outer side of the back of the hand before passing through the second phalanx 1022. The second end of the second rope 1042 is fixed inside the second phalanx 1022.

[0051] One end of the reset rope 106 is connected to the outer side of the back of the hand of the first phalanx 1021, and the other end of the reset rope 106 is connected to the reset assembly 113 for transmission. The reset rope 106 is used to pull the first phalanx 1021 to rotate to the back side under the pull of the reset assembly 113.

[0052] The second rope 1042 is also wound around the first joint 1031 and the second joint 1032. Both ends of the second rope 1042 are fixed to the fixed end 101 and the second phalanx 1022. The difference is that the winding surface of the second rope 1042 at each joint 103 is exactly opposite to that of the first rope 1041. Therefore, the second rope 1042 is used in conjunction with the repositioning assembly 113 to achieve the opposite action to bending the finger, that is, straightening the finger.

[0053] Specifically, when the reset assembly 113 pulls the first phalanx 1021 to rotate around the first joint 1031 toward the outer side of the back of the hand, the contact length between the inner side of the palm of the first joint 1031 and the second rope 1042 gradually increases. Since the end is fixed, the second rope 1042 tends to be pulled out of the first joint 1031 under the action of the first joint 1031. At this time, since the second rope 1042 is still wrapped around the outer side of the back of the hand of the second joint 1032, the contact length between the outer side of the back of the hand of the second joint 1032 and the first rope 1041 gradually decreases. The pulling force generated at the first joint 1031 is transmitted to the second end of the second rope 1042, and pulls the second phalanx 1022 to rotate around the second joint 1032 toward the outer side of the back of the hand, thereby achieving the straightening of the underactuated finger unit 10.

[0054] For example, the reset component 113 in this invention can be a tension-type elastic element. The reset component 113 in this invention can be a tension-type elastic element, which stores energy and provides a stable pull-back force or holding force through its own elastic deformation to achieve functions such as reset, tensioning, or buffering. Specific implementations include, but are not limited to: helical tension springs, wave springs, leaf springs, elastic ropes, or elastic bands.

[0055] In addition, for some scenarios that require the fingers to be spread open to bear force, an electrically driven or hydraulically driven reset component 113 can be used, such as a servo motor 1111, a stepper motor, or a servo motor.

[0056] It is understandable that, since the thumb only has two phalanges 102, the configuration of the first phalange 1021, the second phalange 1022, and the corresponding joint 103 is sufficient for the thumb.

[0057] For the index, middle, ring, and little fingers, the two phalanges 102 closest to the palm can adopt the structure of the first phalange 1021 and the second phalange 1022 described above. In order to achieve a dexterity closer to that of the human hand, a third phalange 1023 can be added on this basis.

[0058] In one embodiment, the underactuated finger unit 10 further includes a third phalanx 1023, a third joint 1033, a third rope 1043, and a fourth rope 1044; the first end of the third phalanx 1023 is pivotally connected to the second end of the second phalanx 1022 via the third joint 1033; the first end of the third rope 1043 is fixed inside the first phalanx 1021, the third rope 1043 first passes around the second joint 1032 on the outer side of the back of the hand and then passes into the second phalanx 1022, the third rope 1043 exits from the second phalanx 1022 and first passes around the hand The third joint 1033 on the inner side of the palm is inserted into the third phalanx 1023, and the second end of the third rope 1043 is fixed inside the third phalanx 1023; the first end of the fourth rope 1044 is fixed inside the first phalanx 1021, the fourth rope 1044 first passes around the second joint 1032 on the inner side of the palm and passes into the second phalanx 1022, the fourth rope 1044 exits from the second phalanx 1022 and first passes around the third joint 1033 on the outer side of the back of the hand and then passes into the third phalanx 1023, and the second end of the fourth rope 1044 is fixed inside the third phalanx 1023.

[0059] The driving relationship between the third phalanx 1023 and the second phalanx 1022 and the first phalanx 1021 corresponds to the driving relationship between the second phalanx 1022 and the first phalanx 1021 and the fixed end 101. The reasons for the winding of the third rope 1043 and the fourth rope 1044 will not be repeated here.

[0060] Based on the above, when the drive rope 105 is tightened, the first phalanx 1021 drives the second phalanx 1022 to rotate toward the inner side of the palm. At this time, since the first end of the third rope 1043 is fixed, the third rope 1043 is subjected to force at the second joint 1032. The force-bearing third rope 1043 pulls the second end of the third rope 1043 fixed in the third phalanx 1023 to rotate toward the inner side of the palm, thereby realizing the same rotation of the first phalanx 1021, the second phalanx 1022, and the third phalanx 1023 toward the inner side of the palm, which is used to simulate the grip of the index finger, middle finger, ring finger, and little finger of a human hand.

[0061] Furthermore, the fourth rope 1044 plays a similar role to the second rope 1042. When the reset rope 106 tightens, the fourth rope 1044 is subjected to force at the second joint 1032. Therefore, the third phalanx 1023 rotates synchronously with the second phalanx 1022 and the first phalanx 1021 toward the outer side of the back of the hand, which is used to simulate the stretching of the index, middle, ring, and little fingers of the human hand.

[0062] It is understandable that, considering application scenarios and cost considerations, different materials can be used for the various ropes 104 in this invention, such as stainless steel wire rope, carbon fiber braided rope, glass fiber rope, nylon braided rope, etc. Any scheme using any material falls within the protection scope of this invention.

[0063] Considering the influence of factors such as elongation on transmission error, in this invention, the first rope 1041, the second rope 1042, the third rope 1043, or the fourth rope 1044 can be aramid ropes.

[0064] The use of aramid fiber rope as the rope 104 of the underactuated dexterous manipulator 1 offers key advantages: low elongation and near-zero creep, effectively reducing transmission errors and ensuring precise and controllable finger movements. It combines ultra-high strength with lightweight characteristics, capable of withstanding gripping loads while reducing energy consumption of the drive mechanism and improving response speed. Aramid fiber rope exhibits excellent abrasion resistance, adaptable to the bending transmission path of the multi-joint 103, and is resistant to chemical corrosion and has wide temperature tolerance, making it suitable for complex working conditions. It is an ideal choice balancing precision, durability, and adaptability to various operating conditions.

[0065] For ease of assembly, in this invention, the first rope 1041, the second rope 1042, or the third rope 1043 can be fixed by screws 108 or by pins.

[0066] Specifically, corresponding threaded holes can be made on the first phalanx 1021, the second phalanx 1022, and the third phalanx 1023 for quick fixation and replacement of the rope 104.

[0067] It is understandable that, such as Figure 1 As shown, in one embodiment of the present invention, the palm body 11 is provided with a plurality of mounting surfaces, and a second magnetic component 114 is provided on the mounting surfaces. A first magnetic component 107 is provided on the end face of the fixed end 101 away from the first joint 1031, and the first magnetic component 107 attracts the second magnetic component 114; among the mounting surfaces and the end face, one surface is provided with a positioning protrusion, and the other surface is provided with a positioning recess, and the positioning protrusion and the positioning recess are correspondingly engaged.

[0068] Since the end face of the fixed end 101 away from the first joint 1031 and the mounting surface are both perpendicular or nearly perpendicular to the contraction direction of the drive rope 105, the magnetic force between the first magnetic component 107 and the second magnetic component 114 hardly participates in the force of the underactuated dexterous manipulator 1 when it expands and contracts. Therefore, it utilizes the portable assembly and disassembly of the magnetic attraction without reducing the structural strength of the underactuated finger unit 10 on the underactuated dexterous manipulator 1.

[0069] In addition to being easy to assemble and disassemble, the first magnetic component 107 and the second magnetic component 114 on the connecting surface can be disconnected in case of overload. When the load is too large, the connecting structure will disengage, causing the underactuated finger unit to fall off the palm body 11, thereby achieving overload protection for the first drive component.

[0070] The combination of screws / pins and magnetic components in various quick-release structures facilitates rapid repositioning both inside the finger and between the finger and palm.

[0071] It is understood that the positioning protrusion can be an integrally formed protrusion on the mounting surface or end face, or it can be a separately fixed protrusion. The positioning protrusion includes, but is not limited to, positioning protrusions, positioning pins, positioning bosses, and positioning dots. Correspondingly, the positioning recess includes, but is not limited to, positioning grooves, positioning holes, positioning pits, and positioning slots.

[0072] The positioning protrusions and recesses provided on the aforementioned end face and mounting surface can increase the lateral force and play a guiding role. Together with the first magnetic material and the second magnetic material, they achieve rapid positioning and firm bonding, combining the advantages of rapid assembly of magnetic materials and the advantages of strong lateral force of positioning structure.

[0073] These protrusions and grooves form a composite interface with the first magnetic component 107 and the second magnetic component 114, which not only enables quick assembly and disassembly but also takes into account the requirements for reset accuracy and strength.

[0074] It is understandable that the mounting surface can have a positioning protrusion or a positioning recess, and similarly, the end face can have a positioning protrusion or a positioning recess, and the form and quantity can be freely combined.

[0075] In one embodiment, a positioning protrusion is provided on the mounting surface, and a corresponding positioning recess is provided on the end face. In another embodiment, a positioning recess is provided on the mounting surface, and a corresponding positioning protrusion is provided on the end face. In yet another embodiment, both a positioning protrusion and a positioning recess are provided on the mounting surface, and both a positioning recess and a positioning protrusion are provided on the end face.

[0076] Furthermore, in this invention, there are no specific limitations on the first magnetic component 107 and the second magnetic component 114. For example, the first magnetic component 107 can be made of a metal material such as iron-nickel, while the second magnetic component 114 can be made of a permanent magnet, electromagnet, etc. In another embodiment, both the first magnetic component 107 and the second magnetic component 114 can be permanent magnets, with their contact surfaces having opposite magnetic poles during installation.

[0077] In addition, the first magnetic component 107 and the second magnetic component 114 can each be selected from one or more magnetic materials according to actual needs.

[0078] In one embodiment, such as Figure 7 As shown, the first power assembly 111 includes a servo motor 1111 and a servo disc 1112. The servo motor 1111 is fixed on the palm body 11, and the other end of the drive rope 105 is wrapped around the circumferential surface of the servo disc 1112. The servo motor 1111 drives the servo disc 1112 to rotate, thereby pulling the second finger bone 1022.

[0079] In the related technologies of this invention, the alignment accuracy of the thumb and other fingers has always been a key technical issue. There is no corresponding structural basis in various technical solutions, and the multi-directional flexibility of the thumb is insufficient, making it difficult to achieve precise pinching.

[0080] Based on the underactuated finger unit described above, in one embodiment of the present invention, as follows: Figure 7 As shown, a second power assembly 115 is provided on the palm body 11, and the second power assembly 115 drives a second gear 1151; a first gear 1011 is fixed at the end of the fixed end 101 away from the first joint 1031, the first gear 1011 is rotatably connected to the palm body 11, the rotation plane of the first gear 1011 is at a preset angle with the rotation plane of any joint 103, and the first gear 1011 is used to drive the underactuated finger unit 10 to swing under the drive of the second gear 1011.

[0081] The underactuated finger unit 10 with a first gear 1011 can be used as a thumb. Since the rotation plane of the first gear 1011 is at a preset angle to the rotation plane of any joint 103, the thumb can not only grasp, but also swing in a direction inconsistent with the grasping direction to achieve pinching with different fingers.

[0082] For example, the preset angle can be 90 degrees, in which case the swing direction is perpendicular to the gripping direction. The preset angle can also be any other angle to adapt to underactuated dexterous manipulators 1 with different proportions.

[0083] Due to the mechanical rigidity of gears, the underactuated finger unit 10 with the first gear 1151 has extremely high swing accuracy and is difficult to deform flexibly in the swing direction. This hybrid drive method, which combines gear rigid drive with end rope flexible drive, achieves precise pinching, solves the problem of inaccurate pinching in the prior art, and provides key technical support for picking up small items.

[0084] like Figure 8 As shown, the range of motion of the underactuated finger units 10 corresponding to the four fingers other than the thumb is demonstrated. The fingertips can fit into the palm of the hand, achieving a range of motion similar to that of a human hand.

[0085] Since the curling motion of the underactuated finger unit 10 corresponding to the thumb is similar to that of the underactuated finger units 10 corresponding to the other four fingers, they will not be shown one by one.

[0086] And such Figure 9 and Figure 10 As shown, the swing range of the underactuated finger unit 10 corresponding to the thumb is illustrated. Taking the view in the figure as an example, Figure 9 The image shows the counterclockwise swing angle range of the underactuated finger unit 10 corresponding to the thumb. Figure 10 The clockwise swing angle range of the underactuated finger unit 10 corresponding to the thumb is shown. It can be seen that the underactuated finger unit 10 corresponding to the thumb in this application can not only cover the swing range of the human hand, but also exceed the swing range of the human hand to achieve a larger angle of movement.

[0087] Because the underactuated finger unit 10 corresponding to the thumb is wiggling, it can perform various actions in conjunction with the underactuated finger units 10 corresponding to the other four fingers: such as Figure 11 As shown, this achieves the effect of pinching with the thumb and forefinger, and as... Figure 12 As shown, the effect of pinching between the thumb and index finger is achieved. It can be seen that the underactuated finger unit 10 and the underactuated dexterous manipulator 1 with rigid-flexible hybrid drive in this invention can fully realize the pinching effect between the thumb and any finger, with a very wide range of gripping range and gripping posture.

[0088] For ease of understanding, the present invention provides several exemplary gripping diagrams, which are not intended to limit the scope of protection of the present invention, nor to limit the applicable scenarios of the present invention.

[0089] like Figure 13 The description demonstrates how the underactuated dexterous manipulator 1 of the present invention grips hand tools. By using different fingers at different angles, it perfectly conforms to the shape of the hand tool. Furthermore, it can grasp various objects such as power tools, umbrellas, and cardboard boxes.

[0090] like Figure 14 As shown, a schematic diagram of a five-finger grasping mechanism is presented. The five fingers work together skillfully to grasp complex, irregularly shaped objects. It can be seen that the underactuated dexterous manipulator 1 of the present invention has a wider range of applications.

[0091] It is understood that both the first power assembly 111 and the second power assembly 115 can be driven by a servo motor 1111. The servo motor 1111 in this invention is only an example. Based on different product requirements, such as different sizes and grip strength levels, different power units can be used, such as servo motors, stepper motors, etc., and can also be used with a gearbox. Further selection based on this falls within the protection scope of this invention.

[0092] Correspondingly, such as Figure 7 As shown, in a second aspect of the present invention, an underactuated dexterous manipulator 1 is provided. The underactuated dexterous manipulator 1 includes a palm body 11 and several underactuated finger units 10 in any embodiment. The palm body 11 is provided with several first driving components, each of which corresponds to one underactuated finger unit 10. The first driving components are used to drive the underactuated finger unit 10 to bend.

[0093] It is understood that the underactuated dexterous manipulator 1 of the present invention includes all the technical contents of the underactuated finger unit 10. Therefore, the embodiments of the underactuated finger unit 10 and its beneficial effects are applicable to the underactuated dexterous manipulator 1 of the present invention, and the present invention will not elaborate on them one by one.

[0094] In an exemplary embodiment, the joint 103 in this invention may be a bearing.

[0095] Furthermore, the present invention quantifies the driving parameters for the structure of the underactuated finger unit 10 and the underactuated dexterous manipulator 1 described above.

[0096] For example, in one embodiment, in terms of control modeling, let q be a vector representing the rotation angle of each joint 103, and u be a vector representing the rotation angle of the servo disk 1112 of the first drive assembly. Through mathematical analysis of the rope winding structure, a clear mapping relationship can be established between the vectors of the rotation angles of each joint 103 and the rotation angles of the servo disk 1112 of the first drive assembly: q = Hu, that is, the change in the rotation angle of each servo motor 1111 can be accurately converted into the change in the rotation angle of the corresponding control joint 103 through this mathematical model.

[0097] The specific mathematical analysis is as follows: We take a three-joint underactuated finger unit from one of the index, middle, ring, or little fingers as an example, such as... Figure 3-5 The three images illustrate examples of the motion of this underactuated finger unit.

[0098] Figure 3 This is the initial state of the fingers before they bend. Figure 4 This demonstrates that, under the physical conditions of joint coupling, at a certain moment when the finger is flexed, the angle of rotation of the third joint (i.e., the DIP joint) is... The second joint (i.e., the PIP joint) rotates at an angle of _____. The first joint (i.e., the MCP joint) rotates at an angle of _____. .

[0099] Comparing the positional changes of rope segments L1, L2, and L3 in Figures a and b, we can obtain: (Formula 1)

[0100] Similarly, we have: (Formula 2)

[0101] Figure 5 This demonstrates the maximum bending state of the underactuated finger unit. Throughout the process, the mathematical relationship between the rotation angle qMCP of the first joint (i.e., the MCP joint) and the servo rotation angle u is: (Formula 3).

[0102] That is: (Formula 4) Where R is the bearing radius at the joint, and r is the servo motor rotation radius. Therefore, there is a clear mapping relationship between the rotation angle of each finger joint and the rotation angle of the servo motor.

[0103] By controlling the rotation angle of the servo motor (or other types of drive components), the gripping of the underactuated dexterous manipulator and the underactuated finger unit can be precisely controlled.

[0104] In summary, this invention provides an underactuated dexterous manipulator that improves gripping accuracy by combining a drive rope with a first rope, while incorporating a reset component to enable finger extension and retraction. The use of materials such as aramid rope optimizes transmission performance and cost. Structurally, the underactuated finger unit comprises multiple ropes, secured with screws for quick assembly, and the magnetic attachment component facilitates disassembly and assembly without compromising mechanical strength. The first drive component corresponds one-to-one with the underactuated finger unit, and a rudder drive enables a second gear to rotate the underactuated finger unit, significantly improving motion accuracy and response speed. This technology balances structural strength and application scenarios while achieving precise control and cost optimization of rope transmission, making it suitable for various working conditions and demonstrating good practicality and innovation.

[0105] The benefits of this invention are reflected in improved gripping accuracy, enhanced movement flexibility, and optimized material properties. Through the synergistic effect of the drive rope and the first rope, the frictional drive problem of traditional underactuated finger units is effectively solved, achieving precise control of rope transmission. Simultaneously, the reset component enables finger extension and retraction, further enhancing the flexibility and adaptability of the underactuated finger unit. In terms of material selection, the application of novel materials such as aramid rope reduces energy consumption and improves the adaptability to transmission errors, ensuring the stability and durability of the underactuated dexterous manipulator under complex working conditions.

[0106] Overall, this invention performs well in terms of accuracy, efficiency, and cost-effectiveness, and has good application prospects.

[0107] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. An underactuated finger unit, characterized in that, The underactuated finger unit (10) is driven by a first power assembly (111). The underactuated finger unit (10) includes a fixed end (101), a first phalanx (1021), a second phalanx (1022), a first joint (1031), a second joint (1032), a first rope (1041), and a drive rope (105). The first end of the first phalanx (1021) is pivotally connected to the fixed end (101) via the first joint (1031); The first end of the second phalanx (1022) is pivotally connected to the second end of the first phalanx (1021) via the second joint (1032); The first end of the first rope (1041) is fixed inside the fixed end (101). The first rope (1041) first passes around the first joint (1031) on the outer side of the back of the hand and then passes through the first phalanx (1021). The first rope (1041) passes out from the first phalanx (1021) and first passes around the second joint (1032) on the inner side of the palm and then passes through the second phalanx (1022). The second end of the first rope (1041) is fixed inside the second phalanx (1022). One end of the drive rope (105) is connected to the inner side of the palm of the first phalanx (1021), and the other end of the drive rope (105) is connected to the first power component (111). The drive rope (105) is used to pull the first phalanx (1021) around the first joint (1031) to rotate towards the inner side of the palm under the pull of the first power component (111).

2. The underactuated finger unit according to claim 1, characterized in that, The underdriven finger unit (10) is also driven by a reset assembly (113), and the underdriven finger unit (10) further includes a second rope (1042) and a reset rope (106). The first end of the second rope (1042) is fixed inside the fixed end (101). The second rope (1042) first passes around the first joint (1031) on the inner side of the palm and then passes through the first phalanx (1021). The second rope (1042) passes out from the first phalanx (1021) and first passes around the second joint (1032) on the outer side of the back of the hand before passing through the second phalanx (1022). The second end of the second rope (1042) is fixed inside the second phalanx (1022). One end of the reset rope (106) is connected to the outer side of the back of the hand of the first phalanx (1021), and the other end of the reset rope (106) is connected to the reset assembly (113) for transmission. The reset rope (106) is used to pull the first phalanx (1021) to rotate to the back side under the pull of the reset assembly (113).

3. The underactuated finger unit according to claim 2, characterized in that, The reset component (113) is a tension-type elastic element.

4. The underactuated finger unit according to claim 2, characterized in that, The underactuated finger unit (10) also includes a third phalanx (1023), a third joint (1033), a third cord (1043), and a fourth cord (1044). The first end of the third phalanx (1023) is pivotally connected to the second end of the second phalanx (1022) via the third joint (1033); The first end of the third rope (1043) is fixed inside the first phalanx (1021). The third rope (1043) first passes around the second joint (1032) on the outer side of the back of the hand and then passes into the second phalanx (1022). The third rope (1043) passes out from the second phalanx (1022) and first passes around the third joint (1033) on the inner side of the palm and then passes into the third phalanx (1023). The second end of the third rope (1043) is fixed inside the third phalanx (1023). The first end of the fourth rope (1044) is fixed inside the first phalanx (1021). The fourth rope (1044) first passes around the second joint (1032) on the inner side of the palm and enters the second phalanx (1022). The fourth rope (1044) exits from the second phalanx (1022) and first passes around the third joint (1033) on the outer side of the back of the hand before entering the third phalanx (1023). The second end of the fourth rope (1044) is fixed inside the third phalanx (1023).

5. The underactuated finger unit according to claim 4, characterized in that, The first rope (1041), the second rope (1042), the third rope (1043), or the fourth rope (1044) are aramid ropes.

6. The underactuated finger unit according to claim 4, characterized in that, The first rope (1041), the second rope (1042), or the third rope (1043) are secured with screws.

7. The underactuated finger unit according to claim 1, characterized in that, The underactuated finger unit (10) is mounted on the palm body (11), and the palm body (11) is provided with a plurality of mounting surfaces, and a second magnetic component (114) is provided on the mounting surfaces. The fixed end (101) is provided with a first magnetic component (107) on the end face away from the first joint (1031), and the first magnetic component (107) is attracted to the second magnetic component (114); Of the mounting surface and the end face, one surface is provided with a positioning protrusion and the other surface is provided with a positioning recess, and the positioning protrusion and the positioning recess are correspondingly engaged.

8. The underactuated finger unit according to claim 1, characterized in that, The first power assembly (111) includes a servo motor (1111) and a rudder disk (1112). The servo motor (1111) is fixed on the palm body (11). The other end of the drive rope (105) is wrapped around the circumferential surface of the rudder disk (1112). The servo motor (1111) drives the rudder disk (1112) to rotate, thereby pulling the second finger bone (1022).

9. The underactuated finger unit according to claim 1, characterized in that, The underactuated finger unit (10) is also driven by a second power assembly (115), which includes a drive motor and a second gear (1151), the drive motor being used to drive the second gear to rotate; The fixed end (101) away from the first joint (1031) is fixed with a first gear (1011). The first gear (1011) meshes with the second gear (1151). The rotation plane of the first gear (1011) is at a preset angle with the rotation plane of any joint (103). The first gear (1011) is used to drive the underactuated finger unit (10) to swing under the rotation of the second gear (1151).

10. An underactuated dexterous manipulator (1), characterized in that, The underactuated dexterous manipulator (1) includes: The palm body (11) is provided with a plurality of first driving components; And several underactuated finger units (10) as described in any one of claims 1-9, wherein the first driving component corresponds one-to-one with the underactuated finger unit (10), and the first driving component is used to drive the underactuated finger unit (10) to bend.

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