A flexible and adaptive underactuated robotic finger

Abstract

The present invention provides a flexible, adaptive, under-actuated robotic finger, comprising a base joint and a phalanx portion connected to the base joint, the base joint comprising a first base and a second base rotatably connected to the first base, the phalanx portion being connected to the second base, the phalanx portion comprising a proximal phalanx, a middle phalanx, and a distal phalanx, the second base comprising a telescopic portion and a fixed portion capable of generating relative displacement, and when the phalanx portion of the robotic finger collides and / or is impacted, the telescopic portion and the fixed portion of the second base generate relative displacement to provide buffering protection. The present invention provides an adaptive, under-actuated robotic finger with a flexible buffering function, the base joint of the robotic finger having two active degrees of freedom, flexion and extension, and lateral swing, the phalanx portion of the robotic finger achieves flexible contact by adapting to the size and shape of an object, and provides collision buffering protection by the relative displacement of the telescopic portion and the fixed portion of the second base.

Description

Technical Field

[0001] The present invention relates to the technical field of manipulators, and in particular to a flexible, adaptive, under-actuated manipulator finger. Background Art

[0002] To assist or replace human hands in manipulating tasks in our daily lives and workplaces, humanoid robotic hands must achieve flexible and precise movements. Ideal fingers possess the necessary degrees of freedom, gripping accuracy, and sufficient gripping force, all within a relatively compact design.

[0003] In the prior art, in order to resolve the contradiction between the number of degrees of freedom, drive mode, weight and structural compactness, humanoid manipulators usually adopt the method of reducing the degrees of freedom of the joints or simplifying the drive and structural design. For example, the fingers do not have the degree of freedom of swing, have only two knuckles, or the motor directly drives the joints, or a single motor drives multiple joints. As a result, the manipulator has poor finger movement flexibility, insufficient load and grasping operation capabilities, and weak impact resistance. For example, Japan's D-hand manipulator can achieve flexion and extension of the fingers, but cannot achieve lateral swing movement, which limits the flexibility of the fingers. If the fingers have the ability to flex and extend and lateral swing at the same time, the complex structure or motion coupling problem caused by the two different axial movements increases the difficulty of manipulator motion control.

[0004] Based on the relationship between the manipulator's degrees of freedom and the number of actuators, it can generally be divided into two types: fully actuated and underactuated. To ensure a compact and humanoid design, underactuated manipulators are often employed. Existing underactuated manipulators are primarily categorized as coupled hands, flat grippers, adaptive hands, coupled adaptive hands, and flat gripper adaptive hands. Coupled hands and flat grippers have fewer degrees of freedom and poor versatility, failing to meet multitasking and high adaptability requirements. Adaptive hands, on the other hand, can automatically adapt to the shape and size of objects. Existing underactuated fingers are complex and less compact, and their processing and assembly are complex, making them difficult to maintain.

[0005] The underactuated robotic finger based on a connecting rod has a large load capacity and can achieve adaptive grasping. However, the rigid connecting rod structure has poor impact resistance. When the robotic finger is hit by a collision and / or impact, it is easy to cause damage to the robotic arm structure, which directly affects the maximum operating speed of the robotic arm. Summary of the Invention

[0006] The purpose of this application is to provide a flexible adaptive under-actuated robotic finger to improve the flexibility of the robotic finger, while being able to achieve adaptive grasping and increase the movement speed of the robotic finger.

[0007] To this end, the present application may adopt the following technical solution: a flexible adaptive under-actuated robotic finger, comprising a base joint and a knuckle portion connected to the base joint, the base joint comprising a first base and a second base rotatably connected to the first base, the knuckle portion being connected to the second base, the second base comprising a telescopic portion and a fixed portion that can produce relative displacement, the knuckle portion comprising a proximal knuckle, a middle knuckle and a distal knuckle, when the knuckle portion of the robotic finger collides and / or is impacted, the telescopic portion and the fixed portion of the second base produce relative displacement to provide buffering protection.

[0008] Furthermore, the second base includes an elastic member and a limiting member arranged between the telescopic part and the fixed part, the elastic member is used to provide a flexible buffer between the telescopic part and the fixed part, and the limiting member is used to limit the moving range of the relative displacement.

[0009] Furthermore, one of the telescopic part and the fixed part includes a cylindrical body, and the other includes an opening that can be set on the outside of the cylindrical body. The elastic part is formed as a compression spring arranged between the opening and the cylindrical body. When the robotic finger collides and / or is impacted, the elastic part is compressed so that the telescopic part and the fixed part are relatively close.

[0010] Furthermore, the knuckle portion includes a proximal knuckle connecting rod and a middle knuckle transmission rod connected to the second base, one of the proximal knuckle connecting rod and the middle knuckle transmission rod is connected to the telescopic portion, and the other is connected to the fixed portion.

[0011] Furthermore, the base joint includes a driving part arranged on the first base and a transmission part that transmits power of the driving part to the second base. The driving part includes a first actuator and a second actuator arranged in parallel. When the first actuator and the second actuator are driven synchronously, the second base rotates around the X-axis; when the second actuator is driven alone, the second base rotates around the Y-axis.

[0012] Furthermore, the transmission part includes a transmission rod that transmits the power of the first actuator to the second base, and a second transmission rod that transmits the power of the second actuator to the second base. The first base and the second base are connected by a first rotating part, the first transmission rod and the second base are connected by a second rotating part, and the second transmission rod and the second base are connected by a third rotating part.

[0013] Furthermore, the X-axes of the first rotating part and the second rotating part are parallel and the Y-axes are collinear, and the X-axes of the second rotating part and the third rotating part are collinear.

[0014] Furthermore, the first rotating part and the second rotating part are arranged on the end surface of the second base, the third rotating part is arranged on the side surface of the second base, and the second transmission rod is connected to the outer side of the second base. When the first actuator and the second actuator are driven synchronously, the first transmission rod and the second transmission rod apply a force to the second base along the YZ plane, and the second base rotates around the X-axis of the first rotating part; when the second actuator is driven alone, the second transmission rod applies a force to the second base along the XZ plane, and the second base rotates around the Y-axis of the first rotating part.

[0015] Furthermore, a tensioning member is provided between the proximal knuckle link and the second base to maintain the initial position of the proximal knuckle link and the second base. When the base joint rotates around the X-axis and the robotic finger moves freely, the proximal knuckle link rotates around the X-axis following the second base; when the proximal knuckle link is subjected to an external force, the proximal knuckle link overcomes the force of the tensioning member and generates relative movement with the second base.

[0016] Furthermore, the knuckle portion includes a distal knuckle transmission rod connected to the middle knuckle transmission rod, a middle knuckle connection rod connected to the proximal knuckle connection rod, and a distal knuckle connection rod connected to the middle knuckle connection rod. The knuckle portion is formed into a five-bar linkage mechanism. When the proximal knuckle connection rod is subjected to external force and the first actuator and the second actuator are driven synchronously, the second base drives the middle knuckle transmission rod and the distal knuckle transmission rod to couple flexion and extension movements to adapt to the shape and size of the grasped object.

[0017] Compared with the prior art, the beneficial effects of the specific embodiments of the present invention are at least the following: 1. A rigid-flexible mechanism is adopted and a rigid connecting rod motion structure is designed to achieve accurate and reliable movement of the robotic finger. At the same time, a flexible telescopic structure is designed to protect the transmission parts and the drive unit, thereby improving the movement speed of the robotic finger; 2. The side-swing motion of the robotic finger is actively driven, thereby improving dexterity and anthropomorphism, and the flexion and extension motion has an adaptive function, thereby reducing the number of drives; 3. The flexion and extension motion is synchronously driven by the first actuator and the second actuator to improve the load and gripping ability; 4. The flexion and extension motion and the side-swing motion of the robotic finger are decoupled to simplify motion control. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a three-dimensional diagram of a mechanical finger according to an embodiment of the present invention;

[0019] Figure 2 yes Figure 1 A cross-sectional view of the robotic finger shown;

[0020] Figure 3a is a schematic diagram of a robotic finger according to an embodiment of the present invention without collision and / or impact;

[0021] Figure 3bis a schematic diagram of a collision and / or impact of a robotic finger according to an embodiment of the present invention;

[0022] Figure 4 is a cross-sectional view of a second base of a robotic finger according to an embodiment of the present invention;

[0023] Figure 5 is a schematic diagram of a robotic finger performing flexion and extension motion according to an embodiment of the present invention;

[0024] Figure 6 is a schematic diagram of a robotic finger performing a lateral swing motion according to an embodiment of the present invention;

[0025] Figure 7 is a schematic diagram of a robotic finger performing a flexion-extension and lateral swing compound motion according to an embodiment of the present invention;

[0026] Figure 8a is a schematic diagram of the free movement of a robotic finger according to an embodiment of the present invention;

[0027] Figure 8b is a schematic diagram of a robotic finger contacting an external object according to an embodiment of the present invention;

[0028] Figure 8c Schematic diagram of a robotic finger grasping an object according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the technical solution of the present invention clearer, the embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the specific description of the implementation mode is only used to teach those skilled in the art how to implement the present invention, rather than to exhaustively list all feasible ways of the present invention, nor to limit the specific scope of implementation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0031] Those skilled in the art will understand that when we refer to an element as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can be intervening elements. In addition, "connected" or "coupled" as used herein can include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0033] The specific embodiment of the present invention protects a mechanical finger, Figure 1-2 The robotic finger is an important component of the robotic hand. The robotic hand exemplarily includes a robotic finger and a palm. When the finger has three knuckles, it extends outward from the palm direction. The knuckle portion 60 of the finger includes a proximal knuckle 61, a middle knuckle 62 and a distal knuckle 63 connected in sequence. When the finger has only two knuckles, it exemplarily includes a proximal knuckle and a middle knuckle.

[0034] Ginseng Figure 1 The robotic finger includes a base joint and a knuckle portion 60 connected to the base joint, the base joint includes a first base 10, a second base 20 rotatably connected to the first base 10, and a knuckle portion 60 connected to the second base 20, the knuckle portion 60 exemplarily includes two knuckles or three knuckles, exemplarily, when the knuckle portion 60 includes three knuckles, the knuckle portion 60 includes a proximal knuckle, a middle knuckle and a distal knuckle. With reference to the orientation definition of human anatomy, the vertical axis direction of the human body is the Z-axis direction, and the first base 10 extends along the Z-axis direction, wherein the first base 10 is a fixed structural member and the second base 20 is a movable structural member. The robotic finger also includes a driving part 30 and a transmission part 40 arranged on the first base 10, and the driving part 30 is used to provide the power required for the finger movement, and the transmission part 40 transmits the power of the driving part 30 to the second base 20, so that the second base 20 can move relative to the first base 10. Exemplarily, the second base 20 is connected to the knuckle part 60, which can drive the knuckle part 60 to move. The first base 10 extends toward the palm or forms a part of the palm, and the second base 20 can rotate relative to the first base 10.

[0035] In a specific embodiment, the finger joint portion 60 is realized by a connecting rod mechanism, which can ensure a large load, operational accuracy and a relatively long service life. The second base 20 is connected to the finger joint portion 60, and the second base 20 includes a telescopic portion 21 and a fixed portion 22. The telescopic portion 21 and the fixed portion 22 can produce relative displacement. There is a spacing between the telescopic portion 21 and the fixed portion 22, and the telescopic portion 21 and the fixed portion 22 are distributed along the Y-axis direction of the second base 20. When the robotic finger collides and / or is impacted, the impact force exerted on the robotic finger will generate a force along the Y-axis direction on the second base 20, and a relative displacement is generated between the telescopic portion 21 and the fixed portion 22 to achieve buffering, thereby protecting the robotic finger from damage. At the same time, the improvement in impact resistance further increases the maximum movement speed of the robotic finger.

[0036] Understandable, Figure 2 The second base 20 includes an elastic member 23 and a limit member 24 arranged between the telescopic part 21 and the fixed part 22. The elastic member 23 can provide flexible movement of relative displacement between the telescopic part 21 and the fixed part 22. When the robotic finger collides and / or is impacted, based on the action of the elastic member 23, the telescopic part 21 and the fixed part 22 can be relatively close to or relatively far away from each other, and the elastic member 23 provides a buffering effect against the collision.

[0037] In a specific embodiment, the elastic member 23 is formed as a compression spring. Figure 3a When the mechanical finger does not collide and / or impact, the compression spring is in an initial elongated state, and the distance between the telescopic portion 21 and the fixed portion 22 is relatively large; Figure 3b When the robotic finger collides and / or is impacted, the compression spring is compressed so that the telescopic part 21 and the fixed part 22 are relatively close to each other, and the compression spring at least partially absorbs the impact force generated by the collision and / or impact, thereby achieving buffering. When the telescopic part 21 and the fixed part 22 are relatively close to each other, the limiter 24 provided between the telescopic part 21 and the fixed part 22 limits the minimum distance between the telescopic part 21 and the fixed part 22 to ensure the normal movement performance of the robotic finger. It is understandable that in other embodiments, the elastic member 23 can also be implemented by a tension spring, a torsion spring, a leaf spring, etc., so as to achieve flexible buffering between the telescopic part 21 and the fixed part 22.

[0038] Specifically, Figure 4One of the telescopic portion 21 and the fixed portion 22 includes a cylindrical body 221, and the other includes an opening 211 that can be set on the outside of the cylindrical body 221. The elastic member 23 is formed as a compression spring, and the compression spring is sleeved on the outside of the cylindrical body 221 to be set between the cylindrical body 221 and the opening 211. When relative displacement occurs between the telescopic portion 21 and the fixed portion 22, the cylindrical body 221 can guide the direction of movement, and the elastic member 23 provides buffering. Exemplarily, when the robotic finger does not collide and / or impact, the second base 20 is in an initial state, at which time the initial position between the telescopic portion 21 and the fixed portion 22 is maintained based on the action of the elastic member 23; when the robotic finger collides and / or impacts, the telescopic portion 21 and the fixed portion 22 move closer, and the minimum distance between the telescopic portion 21 and the fixed portion 22 is limited based on the action of the limiter 24.

[0039] In a specific embodiment, the limiting member 24 can be formed as a limiting screw and a waist-shaped hole (not shown in the figure), and the waist-shaped hole is formed in the telescopic part 21 or the fixed part 22. The limiting screw can be arranged in the waist-shaped hole. When the telescopic part 21 and the fixed part 22 undergo relative displacement, the limiting screw moves along the waist-shaped hole. The movable range of the limiting screw in the waist-shaped hole limits the moving range of the telescopic part 21 and the fixed part 22. Exemplarily, the limiting member 24 can be used to limit the maximum distance and the minimum distance between the telescopic part 21 and the fixed part 22, or to limit one of the maximum distance and the minimum distance between the telescopic part 21 and the fixed part 22.

[0040] Further, refer to Figure 1-2 The proximal knuckle is connected to the second base, and the proximal knuckle includes a proximal knuckle connecting rod 611 and a middle knuckle transmission rod 621 connected to the second base 20. Exemplarily, the proximal knuckle connecting rod 611 and the middle knuckle transmission rod 621 are respectively connected to the second base 20, and there is a gap between the proximal knuckle connecting rod 611 and the middle knuckle transmission rod 621. Exemplarily, one of the proximal knuckle connecting rod 611 and the middle knuckle transmission rod 621 is connected to the telescopic portion 21 of the second base 20, and the other is connected to the fixed portion 22 of the second base 20. Exemplarily, when the robotic finger collides and / or is impacted, the impact force is transmitted along the force-bearing point to the middle knuckle transmission rod 621 or the proximal knuckle connecting rod 611, thereby causing the telescopic portion 21 and the fixed portion 22 to produce relative displacement to achieve buffering.

[0041] The first base 10 and the second base 20 are rotatably connected, the second base 20 can rotate relative to the first base 10, and the finger joint 60 is connected to the second base 20. For example, Figure 5The knuckle portion 60 includes a proximal knuckle 61, a middle knuckle 62, and a distal knuckle 63. The driving portion 30 of the robotic finger is disposed at one end of the first base 10, and the second base 20 is disposed at the other end of the first base 10. The driving portion 30 includes a first actuator 31 and a second actuator 32 disposed in parallel. Exemplarily, the transmission portion 40 is a parallel structure to transmit the power of the first actuator 31 and the second actuator 32 disposed in parallel to the second base 20. When the first actuator 31 and the second actuator 32 are driven synchronously, the second base 20 rotates along the X-axis (the coronal axis of the human body); Figure 6 When the second actuator 32 is driven alone, the second base 20 rotates around the Y-axis (refer to the sagittal axis of the human body). When the second base 20 rotates around the X-axis, the robotic finger can perform flexion / extension movement; when the second base 20 rotates around the Y-axis, the robotic finger performs adduction / abduction movement. Specifically, when the second base 20 rotates around the X-axis, when the robotic finger moves freely, the knuckle portion 60 of the robotic finger rotates freely around the X-axis; when the second base 20 rotates around the X-axis to grasp an object, the knuckle portion 60 of the robotic finger bends to adapt to the shape and size of the grasped object, thereby achieving flexion / extension movement of the robotic finger.

[0042] Understandable, Figure 7 When the first actuator 31 and the second actuator 32 are driven asynchronously, the second base 20 rotates around the X-axis direction and the Y-axis direction simultaneously to perform a compound motion of rotating around the X-axis and the Y-axis.

[0043] During the research process of this technical solution, the inventors of this application discovered that, based on bionics research, the abduction / adduction movement of human fingers is, in most cases, used to reposition the fingers rather than exert significant force. This movement of the human hand is primarily accomplished by the interosseous muscles located in the palm. This means that the adduction / abduction movement of the fingers requires only a small driving force. Therefore, the adduction / abduction movement of the fingers can be achieved with a small driving force, while the flexion / extension movement of the fingers requires a relatively large driving force. Therefore, in this solution, when the fingers perform flexion / extension movement, power is provided by both the first actuator 31 and the second actuator 32, thereby providing a relatively large driving force, ensuring that the fingers have sufficient gripping force, thereby reducing the size of a single actuator. When the fingers perform adduction / abduction movement, power is provided only by the second actuator 32.

[0044] By setting the driving unit 30 as described above, two degrees of freedom can be provided for the base joint of the finger while ensuring that the driving unit is relatively small, while ensuring that the finger has sufficient gripping force, and at the same time, the utilization efficiency of the actuator can be improved.

[0045] Further, refer to Figure 5-7The transmission part 40 includes a first transmission component 41 and a second transmission component 42. The first transmission component 41 is connected to the first actuator 31 to transmit the power of the first actuator 31, and the second transmission component 42 is connected to the second actuator 32 to transmit the power of the second actuator 32. Exemplarily, the transmission part 40 adopts an asymmetric parallel transmission mechanism. When the first actuator 31 and the second actuator 32 are driven synchronously, the first transmission component 41 and the second transmission component 42 transmit the power of the first actuator 31 and the second actuator 32 to the second base 2; when driven by the second actuator 32 alone, the second transmission component 42 transmits the power of the second actuator 32 to the second base 20.

[0046] Furthermore, the second base 20 is rotatable relative to the first base 10, and the first base 10 and the second base 20 are connected via a first rotating portion 51. Furthermore, the first transmission assembly includes a first linear motion member and a first transmission rod 411. The first linear motion member is connected to the first actuator to generate linear motion based on the power of the first actuator 31. The first transmission rod 411 has one end connected to the first linear motion member and the other end connected to the second base 20 to transmit power to the second base 20. The first transmission rod 411 and the second base 20 are connected via a second rotating portion 52. Similarly, the second transmission assembly 42 includes a second linear motion member and a second transmission rod 421. The second linear motion member is connected to the second actuator 32 to generate linear motion based on the power of the second actuator 32. The second transmission rod 421 has one end connected to the second linear motion member and the other end connected to the second base 20 to transmit power to the second base 20. The second transmission rod 421 and the second base 20 are connected via a third rotating portion 53.

[0047] It is understood that the first rotating portion 51, the second rotating portion 52, and the third rotating portion 53 can rotate in at least two directions, so that the base joint of the robotic finger can achieve two degrees of freedom of movement. For example, the first rotating portion 51, the second rotating portion 52, and the third rotating portion 53 can use connecting components such as universal joints and cross shafts to achieve vertical axis rotation.

[0048] Specifically, the first rotating part 51 and the second rotating part 52 are arranged on the end surface of the second base 20 , the third rotating part 53 is arranged on the side surface of the second base 20 , and the second transmission rod 421 is connected to the outer side of the second base 20 .

[0049] Specifically, when the first actuator 31 and the second actuator 32 are driven synchronously, it is understood that the first actuator 31 and the second actuator 32 provide driving forces of equal magnitude and direction, so that in a theoretical state, the first transmission assembly 41 and the second transmission assembly 42 apply forces of equal magnitude and direction to the second base 20. The first transmission assembly 41 and the second transmission assembly 42 apply forces to the second base 20 along the YZ plane, and the first transmission rod 411 and the second transmission rod 421 move within the YZ plane, causing the second base 20 to rotate about the X-axis of the first rotating portion 51. When driven solely by the second actuator 32, only the second transmission assembly 42 applies force to the second base 20. The second transmission assembly 42 applies forces to the second base 20 along the XZ plane, and the second transmission rod 421 moves within the XZ plane, causing the second base 20 to rotate about the Y-axis of the first rotating portion 51. Furthermore, a spherical bearing 422 is provided between the second transmission rod 421 and the second linear motion member to ensure the flexibility of the movement of the second transmission rod 421.

[0050] As can be understood, when the first actuator 31 and the second actuator 32 are driven asynchronously, the robotic finger performs a composite motion of the two aforementioned motions. When the base joint performs a composite motion of rotation about the X-axis and rotation about the Y-axis, the second transmission assembly 42 generates spatial motion, and the spherical bearing 422 ensures the flexibility of the second transmission rod's motion.

[0051] The above-mentioned first linear motion member, first transmission rod 411 and second rotating part 52 constitute the first branch of the base finger base joint parallel mechanism, and the second linear motion member, spherical bearing 422, second transmission rod 421 and third rotating part 53 constitute the second branch of the finger base joint parallel mechanism, wherein the first branch is a planar motion branch and the second branch is a spatial motion branch.

[0052] The base joint of the robotic finger achieves two degrees of freedom of rotation through a parallel mechanism with asymmetric branches. Compared to the prior art method of achieving two degrees of freedom of rotation of the base joint using a symmetric branched parallel mechanism, the two branches are independent of each other and do not affect each other, achieving kinematic decoupling. Furthermore, the first and second branches are azimuthally distributed along the X-axis, and the synchronous movement of the two branches enables the second base 20 to rotate about the X-axis, resolving the problem of insufficient load-bearing capacity and rigidity of the kinematic decoupling asymmetric branched parallel mechanism compared to the strongly coupled symmetric branched parallel mechanism.

[0053] Preferably, the X-axes of the first rotating part 51 and the second rotating part 52 are parallel, and the Y-axes of the first rotating part 51 and the second rotating part 52 are collinear; the X-axes of the second rotating part 52 and the third rotating part 53 are collinear, thereby further ensuring the decoupling between the rotational movement of the second base 20 around the X-axis and the rotational movement around the Y-axis.

[0054] Specifically, the driving portion 30 and the transmission portion 40 extend in the same direction, the first transmission rod is disposed above the first linear motion member, and the second transmission rod is disposed above the second linear motion member.

[0055] Exemplarily, the first linear motion member and the second linear motion member can be realized by a screw 412 assembly or a gear rack assembly. Preferably, in this embodiment, linear motion is realized by a screw assembly. The screw assembly occupies less space than the gear rack assembly and can enable the first linear motion member and the second linear motion member to extend in the same direction as the driving part 30. Exemplarily, the first linear motion member and the second linear motion member respectively include a screw 412, a nut 413, a nut seat 414 and a guide 415, the nut 413 is mounted on the screw 412, the nut seat 414 is connected to the nut 413 and is sleeved on the guide 415, and the guide 415 can exemplarily include a guide rod, one end of the first transmission rod 411 is connected to the nut seat 414 of the first linear motion member, and the other end is connected to the X-axis of the second rotating part 52; one end of the second transmission rod 421 is connected to the nut seat of the second linear motion member through a spherical bearing 422, and the other end is connected to the Y-axis of the third rotating part 53.

[0056] Specifically, the nut seat 414 of the first transmission assembly 41 and the nut seat 414 of the second transmission assembly 42 are coplanar in the XY plane, so that when the first actuator 31 and the second actuator 32 are driven synchronously, the first transmission assembly 41 and the second transmission assembly 42 transmit forces of the same magnitude and direction to the second base 20, thereby realizing the rotation of the second base 20 around the X-axis of the first rotating part 51.

[0057] Furthermore, the knuckle portion 60 of the robotic finger includes a plurality of knuckles, and the knuckle portion 60 includes a proximal knuckle connecting rod 611 and a middle knuckle transmission rod 621 connected to the second base 20, one of the proximal knuckle connecting rod 611 and the middle knuckle transmission rod 621 is connected to the telescopic portion 21, and the other is connected to the fixed portion 22, and the middle knuckle transmission rod 621 continues to transmit power forward. For example, the middle knuckle transmission rod 621 is connected to the distal knuckle transmission rod 631, see Figure 3a-3b When the fingers collide and / or impact, the distal phalanx 63 bends and applies force to the second base 20 via the distal phalanx transmission rod 631 and the middle phalanx transmission rod 621. Relative motion occurs between the telescopic portion 21 and the fixed portion 22 of the second base 20, thereby achieving cushioning. In a preferred embodiment, the proximal phalanx connecting rod 611 is connected to the fixed portion 22, and the middle phalanx transmission rod 621 is connected to the telescopic portion 21. The distal phalanx transmission rod 631 transmits the force to the middle phalanx transmission rod 621, thereby applying force to the telescopic portion 21 of the second base 20, causing the elastic member 23 between the telescopic portion 21 and the fixed portion 22 to be compressed, achieving a cushioning effect.

[0058] Among them, Figure 4 A tensioning member 6110 is provided between the proximal knuckle link 611 and the second base 20 to maintain the initial position of the proximal knuckle link 611 and the second base 20. For example, the initial position is when the proximal knuckle link 611 and the second base 20 maintain a perpendicular relationship. Specifically, the tensioning member 6110 can be formed as a torsion spring. When the tensioning member is not provided, the second base 20 and the proximal knuckle link 611 have two degrees of freedom: the proximal knuckle 61 follows the movement of the second base 20, and the proximal knuckle 61 moves relative to the second base 20. By providing the tensioning member 6110, the two degrees of freedom of the proximal knuckle 61 during natural movement are limited to one degree of freedom, namely, the proximal knuckle 61 follows the movement of the second base 20, thereby facilitating motion control of the knuckle 60.

[0059] Specifically, the knuckle portion 60 includes a distal knuckle transmission rod 631 connected to the middle knuckle transmission rod 621, a middle knuckle connecting rod 622 connected to the proximal knuckle connecting rod 611, and a distal knuckle connecting rod 632 connected to the middle knuckle connecting rod 622. The knuckle portion 60 is formed into a five-link mechanism. When the mechanical finger moves freely, the knuckle portion 60 is connected to the distal knuckle connecting rod 631. Figure 8a , the proximal knuckle link 611 rotates around the X-axis following the second base 20. At this time, there is no relative movement between the proximal knuckle link 611 and the second base 20, and the proximal knuckle link 611 and the second base 20 maintain an initial position. For example, the initial position is that the proximal knuckle link 611 is perpendicular to the second base 20; when the proximal knuckle link 611 is subjected to an external force, the driving part continues to work so that the transmission part 40 continues to transmit power to the second base 20. Figure 8b When the proximal knuckle link 611 is initially subjected to an external force, the rotation of the second base 20 around the X-axis is restricted by the external force due to the tension between the proximal knuckle link 611 and the second base 20. When the external force continues to act on the proximal knuckle link 611, the reference Figure 8c The driving unit 30 applies additional torque to overcome the force of the tensioning member 6110, so that the second base 20 can continue to rotate around the X-axis, and drive the middle knuckle transmission rod 621 and the distal knuckle transmission rod 631 to couple the flexion and extension movement, and the proximal knuckle connecting rod 611 rotates relative to the second base 20, thereby allowing the robotic finger to adapt to the shape and size of the grasped object.

[0060] Specifically, when the second base 20 rotates around the X axis, a tensioning member 6110 is provided between the second base 20 and the proximal knuckle link 611. When the mechanical finger moves freely, the tensioning member 6110 is provided between the second base 20 and the proximal knuckle link 611. Figures 8a-8b , the proximal knuckle link 611 rotates with the second base 20, and the proximal knuckle link 611 is perpendicular to the second base 20; when the proximal knuckle link 611 contacts an external object and is subjected to an external force, the movement of the second base 20 is blocked. Figure 8c When the driving unit 30 applies additional torque to overcome the force of the tensioning member 6110, the second base 20 continues to rotate around the X-axis, and drives the middle knuckle transmission rod 621 and the distal knuckle transmission rod 631 to couple the flexion and extension movements, and the proximal knuckle connecting rod 611 rotates relative to the second base 20. At this time, an acute angle is formed between the proximal knuckle connecting rod 611 and the second base 20. The middle knuckle connecting rod 622 and the distal knuckle connecting rod 632 adapt to the shape and size of the grasped object, thereby realizing adaptive grasping of external objects.

[0061] In which, when the second base 20 rotates around the X-axis, the second base 20 moves in the YZ plane, a finger joint portion 60 is provided on one side of the second base 20, and the first base 10 is provided on the other side, a first rotation limiter 24 is provided on one side of the finger joint portion 60 of the second base 20, and a second rotation limiter 24 is provided between the second base 20 and the first base 10. When the second base 20 rotates around the X-axis and the proximal knuckle link 611 and the second base 20 produce relative motion, the second base 20 rotates in the direction close to the proximal knuckle link 611, and the first rotation limiter limits the minimum angle α between the second base 20 and the proximal knuckle link 611; at the same time, the second rotation limiter limits the initial position between the second base 20 and the first base 10. Exemplarily, the second rotation limiter is arranged at the connection between the first base 10 and the second base 20, limiting the maximum angle β of the second base 20 rotating around the X-axis. The first rotation limiter and the second rotation limiter limit the range of motion of the second base 20 rotating around the X-axis. Exemplarily, the second rotation limiter keeps the first base 10 and the second base 20 vertical, that is, β = 90 degrees, that is, the rotation range of the second base 20 around the X-axis is [α, β].

[0062] The beneficial effects of the above preferred embodiments are: the robotic finger adopts a connecting rod structure, and a retractable structure of the second base is set at the same time. The rigid and flexible structure ensures the gripping force and impact resistance of the finger, thereby improving the maximum operating speed of the robotic finger; an asymmetric parallel branch chain design of the base joint is adopted, and the position distribution design of the rotating part is used at the same time, so that the rotational motion of the base joint around the X-axis and Y-axis is decoupled, which simplifies the difficulty of motion control.

[0063] Finally, it should be noted that due to the limitations of textual expression, the above description is merely illustrative and not exhaustive. The present invention is not limited to the disclosed embodiments. Without departing from the scope and spirit of the above examples, improvements and modifications may be made by those skilled in the art, and such improvements and modifications should also be considered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A flexible adaptive underactuated robotic finger, characterized in that: It includes a base joint and a knuckle part connected to the base joint, the base joint includes a first base extending along the Z axis, a second base rotatably connected to the first base, the knuckle part is connected to the second base, the second base includes a telescopic part and a fixed part that can produce relative displacement, the knuckle part includes a proximal knuckle, a middle knuckle and a distal knuckle, when the knuckle part of the robotic finger collides and / or is impacted, the telescopic part and the fixed part of the second base produce relative displacement to provide buffering protection; the knuckle part includes a proximal knuckle connecting rod and a middle knuckle transmission rod, the proximal knuckle connecting rod and the middle knuckle transmission rod are connected to the second base at intervals along the Y axis direction, one of the proximal knuckle connecting rod and the middle knuckle transmission rod is connected to the telescopic part, and the other is connected to the fixed part.

2. The flexible adaptive underactuated robotic finger according to claim 1, characterized in that: The second base includes an elastic member and a limiting member arranged between the telescopic portion and the fixed portion, the elastic member is used to provide a flexible buffer between the telescopic portion and the fixed portion, and the limiting member is used to limit the moving range of the relative displacement.

3. The flexible adaptive underactuated robotic finger according to claim 2, characterized in that: One of the telescopic part and the fixed part includes a cylindrical body, and the other includes an opening that can be set on the outside of the cylindrical body. The elastic part is formed as a compression spring arranged between the opening and the cylindrical body. When the robotic finger collides and / or is impacted, the elastic part is compressed to make the telescopic part and the fixed part relatively close.

4. The flexible adaptive underactuated robotic finger according to claim 1, characterized in that: The base joint includes a driving part arranged on the first base and a transmission part that transmits power of the driving part to the second base. The driving part includes a first actuator and a second actuator arranged in parallel. When the first actuator and the second actuator are driven synchronously, the second base rotates around the X-axis; when driven by the second actuator alone, the second base rotates around the Y-axis.

5. The flexible adaptive underactuated robotic finger according to claim 4, characterized in that: The transmission part includes a first transmission rod for transmitting power of the first actuator to the second base, and a second transmission rod for transmitting power of the second actuator to the second base. The first base and the second base are connected by a first rotating part, the first transmission rod and the second base are connected by a second rotating part, and the second transmission rod and the second base are connected by a third rotating part.

6. The flexible adaptive underactuated robotic finger according to claim 5, characterized in that: The X axes of the first rotating part and the second rotating part are parallel and the Y axes are collinear. The X axes of the second rotating part and the third rotating part are collinear.

7. The flexible adaptive underactuated robotic finger according to claim 5, characterized in that: The first rotating part and the second rotating part are arranged on the end surface of the second base, the third rotating part is arranged on the side surface of the second base, and the second transmission rod is connected to the outer side of the second base. When the first actuator and the second actuator are driven synchronously, the first transmission rod and the second transmission rod apply a force to the second base along the YZ plane, and the second base rotates around the X-axis of the first rotating part; when the second actuator is driven alone, the second transmission rod applies a force to the second base along the XZ plane, and the second base rotates around the Y-axis of the first rotating part.

8. The flexible adaptive underactuated robotic finger according to claim 4, characterized in that: A tensioning member is provided between the proximal knuckle connecting rod and the second base to maintain the initial position of the proximal knuckle connecting rod and the second base. When the second base rotates around the X-axis and the robotic finger moves freely, the proximal knuckle connecting rod rotates around the X-axis following the second base; when the proximal knuckle connecting rod is subjected to an external force, the proximal knuckle connecting rod overcomes the force of the tensioning member and generates relative movement with the second base.

9. The flexible adaptive underactuated robotic finger according to claim 8, characterized in that: The knuckle part includes a distal knuckle transmission rod connected to the middle knuckle transmission rod, a middle knuckle connection rod connected to the proximal knuckle connection rod, and a distal knuckle connection rod connected to the middle knuckle connection rod. The knuckle part is formed into a five-bar linkage mechanism. When the proximal knuckle connection rod is subjected to external force and the first actuator and the second actuator are driven synchronously, the second base drives the middle knuckle transmission rod and the distal knuckle transmission rod to couple flexion and extension movements to adapt to the shape and size of the grasped object.

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