A pinch adaptive mechanical finger, a mechanical hand and a pinch method

Abstract

The application discloses a kind of grab pinch adaptive five connecting rod mechanical fingers, mechanical hands and grab pinch method, belong to robot technical field.A kind of grab pinch adaptive mechanical finger, comprising: base and the grab component of setting on base, grab component includes near phalange and far phalange;Near phalange includes first connecting rod, second connecting rod, third connecting rod, fourth connecting rod and fifth connecting rod sequentially rotationally connected into annular in head and tail;The position of first connecting rod and fifth connecting rod connection is fixedly connected with base;Second connecting rod is connected with driver, and driver drives second connecting rod to rotate;Spring is arranged between second connecting rod and third connecting rod;Fourth connecting rod is parallel with first connecting rod, and the distance between two connecting points of fourth connecting rod is same with the distance between two connecting points of first connecting rod;Far phalange is fixedly connected with fourth connecting rod.The mechanical finger has the characteristics of less connecting rod, less transmission pair, no need to pre-tighten, higher transmission precision, less motor, simple control, etc., with higher reliability.

Description

Technical Field

[0001] This invention relates to the field of robotics, specifically to a grasping adaptive five-link mechanical finger, a robotic hand, and a grasping method. Background Technology

[0002] Robotic arms are important end-effectors for robots to perform typical actions such as grasping, twisting, inserting, pulling, and dragging. Robotic fingers are the core components for realizing these actions. Robotic fingers should have characteristics such as simple structure, high load-bearing capacity, adaptability to non-cooperative targets, simple control, and stability and reliability, so that they can be better applied in the field of industrial engineering.

[0003] Currently, the driving methods for the joints within a robotic finger mainly include direct motor drive, linkage coupling drive, and tendon coupling drive. In direct motor drive fingers, the motor is located inside the robotic finger. Due to space constraints, the motor is relatively small, resulting in a smaller grasping force. Furthermore, since the movement of each phalanx is driven by a motor, real-time synchronous control of the finger motors is required during grasping to ensure that multiple phalanxes are in constant contact with the object being grasped, making this type of finger control quite complex. Linkage coupling drive fingers often employ a double-link coupling drive. One set of links is a quadrilateral link used to achieve rotational grasping around the palm near the phalanx; the other set of links is a parallelogram link used to ensure a constant pointing direction of the distal phalanx (i.e., the fingertip), achieving a flat gripping motion. Linkage coupling drive fingers have a large number of links, numerous internal rotating pairs, and complex transmission. Under conditions of large temperature differences or heavy loads, the rotating shaft system of the link assembly is prone to deformation and jamming, resulting in poor adaptability to spatial environments. In tendon-coupled driven fingers, the gripping motion is controlled by the tension of the driving tendon. Since a single driving tendon can only provide unidirectional tension, at least two driving sources are required for the flexion / extension movement of a single phalanx. This results in a large number of driving sources and complex control in robotic hands using this type of finger. Furthermore, the driving tendon is typically a flexible rope, which tends to stretch and lengthen during use, weakening the finger's rigidity and reducing transmission accuracy. Pre-tensioning is required after a period of use, increasing maintenance costs.

[0004] Chinese patent CN201711492166.X proposes a deformable three-finger dexterous hand, with each finger using a double parallelogram mechanism and an underactuated method; patent CN201520889527.4 proposes an underactuated three-finger dexterous hand, with each finger driven by tendon cords; patent CN201721807938.X proposes a modular five-finger dexterous end effector, with each finger's transmission method designed as a "single motor-double tendon cord" mechanism, but the tendon cord transmission has shortcomings such as pretension and low transmission accuracy. Summary of the Invention

[0005] The purpose of this invention is to provide a gripping adaptive five-link mechanical finger, a mechanical hand, and a gripping method to solve the problems of existing mechanical fingers having a large number of links, multiple transmission pairs, low pre-tensioning and transmission accuracy, a large number of motors, and complex control in the driving methods of each joint.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0007] An adaptive grasping mechanical finger includes: a base and a grasping assembly disposed on the base, the grasping assembly including a proximal phalanx and a distal phalanx; the proximal phalanx includes a first link, a second link, a third link, a fourth link, and a fifth link that are rotatably connected end to end in a ring; the connection point between the first link and the fifth link is fixedly connected to the base; the second link is connected to a driver, the driver driving the second link to rotate; a spring is provided between the second link and the third link; the fourth link is parallel to the first link, and the distance between the two connection points of the fourth link is the same as the distance between the two connection points of the first link; the distal phalanx is fixedly connected to the fourth link.

[0008] Furthermore, one end of the first link is connected to one end of the base, and the other end of the first link is away from the first link; one end of the distal phalanx is fixedly connected to the fourth link, and the other end of the distal phalanx is away from the first link.

[0009] Furthermore, the angle between the first link and the base is any value between 90° and 270°, and the angle between the distal phalanx and the fourth link is greater than 0° and less than 180°.

[0010] Furthermore, the angle between the first link and the base is 180°, and the angle between the distal phalanx and the fourth link is 90°.

[0011] Furthermore, the angle between the second and third links can be any value between 0° and 180°.

[0012] Furthermore, a limiter is provided at the connection position between the second link and the third link to prevent the initial angle between the second link and the third link from decreasing under the action of the spring.

[0013] A robotic hand based on the above-mentioned gripping adaptive mechanical finger has at least two gripping components on its base, and the two gripping components are installed in opposite directions.

[0014] A grasping method of the above-mentioned robotic arm includes envelope grasping and clamping pinching;

[0015] Envelope capture includes the following steps:

[0016] S11: Place the object on the base;

[0017] S12: The driver drives the second link to rotate around the first link, thereby driving the third link, fourth link, fifth link and distal phalanx to move synchronously until the fifth link contacts the object. During the movement, the fourth link and distal phalanx translate and keep the fourth link parallel to the first link, while the angle between the second link and the third link remains unchanged.

[0018] S13: The driver drives the second link to continue rotating around the first link. The angle between the second link and the third link gradually increases, the spring is gradually stretched, and the distal phalanx rotates with the fourth link until the distal phalanx contacts the object. At this time, the base of all gripping components, the fifth link and the distal phalanx together envelop and grip the object.

[0019] The clamping and pinching process includes the following steps:

[0020] S21: Place the object on top of the base;

[0021] S22: The driver drives the second link to rotate around the first link, thereby driving the third link, fourth link, fifth link and distal phalanx to move synchronously until the distal phalanx contacts the object. At this time, the distal phalanxes of all gripping components work together to perform the previous parallel clamping and pinching of the object. During the movement, the fourth link and distal phalanx translate and keep the fourth link parallel to the first link, while the angle between the second link and the third link remains unchanged.

[0022] The present invention has the following beneficial effects:

[0023] The mechanical finger of this invention includes a base, a proximal phalanx, and a distal phalanx. The proximal phalanx consists of five links and one spring, driven by a single drive source, enabling the proximal and distal phalanxes to couple and move in unison. This allows for adaptive envelope grasping of the target and parallel pinching of the fingertip. Under the same functional conditions as existing mechanical fingers, the finger transmission scheme of this invention greatly simplifies the complexity of the transmission mechanism, featuring fewer links, fewer transmission pairs, no need for pre-tensioning, higher transmission accuracy, fewer motors, and simpler control, resulting in higher reliability. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the gripping adaptive mechanical finger of Embodiment 1 of the present invention;

[0025] Figure 2 This is a schematic diagram of the process of envelope grasping in Embodiment 3 of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of Embodiment 3 of the present invention during envelope grasping;

[0027] Figure 4 This is a schematic diagram of the structure of Embodiment 4 of the present invention during clamping and pinching.

[0028] In the diagram: 10 - base; 20 - distal phalanx; 21 - first link; 22 - second link; 23 - third link; 24 - fourth link; 25 - fifth link; 26 - spring; 30 - distal phalanx. Detailed Implementation

[0029] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0030] Example 1:

[0031] Please refer to Figure 1 This embodiment provides a grasping adaptive five-link mechanical finger, which includes a base 10 and a grasping component disposed on the base 10. The grasping component is the finger, and the base 10 is the foundation for the finger's mounting and is part of the palm. The grasping component includes a proximal phalanx 20 and a distal phalanx 30, which are coupled and linked together. This not only enables adaptive envelope grasping of the target but also parallel pinching and gripping of the target's fingertips. Under the same functional conditions as existing mechanical fingers, the finger transmission scheme of this embodiment greatly simplifies the complexity of the transmission mechanism, featuring fewer links, fewer transmission pairs, no need for pre-tensioning, higher transmission accuracy, fewer motors, and simpler control, resulting in higher reliability.

[0032] The proximal phalanx 20 includes a first link 21, a second link 22, a third link 23, a fourth link 24, and a fifth link 25 that are rotatably connected in a ring from end to end, namely, respectively Figure 1 In the AB, BC, CD, DE, and EA, the distal phalanx is... Figure 1 In the diagram, the first link 21 and the fifth link 25 are fixedly connected to the base 10, meaning the first link 21 and the base 10 are connected as a single unit and will not rotate. The second link 22 is connected to a driver, which drives the second link 22 to rotate around the first link 21. A spring 26 is provided between the second link 22 and the third link 23; one end of the spring 26 is connected to the second link 22, and the other end is connected to the third link 23. The fourth link 24 is parallel to the first link 21, and the distance between the two connection points of the fourth link 24 is the same as the distance between the two connection points of the first link 21, meaning the line connecting ABDE is a parallelogram. The distal phalanx 30 is fixedly connected to the fourth link 24.

[0033] Since the line connecting ABCD is a parallelogram, when the driver drives the second link 22 to rotate, the first link 21 and the fourth link 24 remain parallel before the proximal phalanx 20 or the distal phalanx 30 contacts the object, and the angle between the second link 22 and the third link 23 will not change.

[0034] In this embodiment, one end of the first link 21 is connected to one end of the base 10, and the other end of the first link 21 is away from the first link 21; one end of the distal phalanx 30 is fixedly connected to the fourth link 24, and the other end of the distal phalanx 30 is away from the first link 21.

[0035] In this embodiment, the angle between the first link 21 and the base 10 is any value between 90° and 270°, the angle between the distal phalanx 30 and the fourth link 24 is greater than 0° and less than 180°, and the initial angle between the second link 22 and the third link 23 is any value between 0° and 180°. Preferably, the angle between the first link 21 and the base 10 is 180°, the angle between the distal phalanx 30 and the fourth link 24 is 90°, and the initial angle between the second link 22 and the third link 23 is 120°.

[0036] In order to prevent the initial angle between the second link 22 and the third link 23 from decreasing under the action of the spring 26, in this embodiment, a limiter is provided at the connection position between the second link 22 and the third link 23.

[0037] In this embodiment, the driver only needs to be able to rotate the second link 22, preferably a drive motor.

[0038] Example 2:

[0039] This embodiment provides a robotic hand based on the gripping adaptive mechanical finger of Embodiment 1. The robotic hand includes a base 10 and at least two gripping components disposed on the base 10, wherein the two gripping components are installed in opposite directions, thereby enabling envelope gripping and pinching.

[0040] Example 3:

[0041] This embodiment provides a grasping method for a robotic arm based on Embodiment 2, including two aspects: envelope grasping and clamping pinching.

[0042] Please refer to Figure 2 and Figure 3 Envelope capture includes the following steps:

[0043] S11: Place the object on the base 10;

[0044] S12: The driver drives the second link 22 to rotate around the first link 21, thereby driving the third link 23, the fourth link 24, the fifth link 25 and the distal phalanx 30 to move synchronously until the fifth link 25 contacts the object. During the movement, the fourth link 24 and the distal phalanx 30 translate and keep the fourth link 24 parallel to the first link 21. The angle between the second link 22 and the third link 23 remains unchanged.

[0045] S13: The driver drives the second link 22 to continue rotating around the first link 21. The angle between the second link 22 and the third link 23 gradually increases, the spring 26 is gradually stretched, and the distal finger joint 30 rotates with the fourth link 24 until the distal finger joint 30 contacts the object. At this time, the base 10 of all gripping components, the fifth link 25 and the distal finger joint 30 together envelop and grip the object.

[0046] Please refer to Figure 4 The clamping and pinching process includes the following steps:

[0047] S21: Place the object above the base 10;

[0048] S22: The driver drives the second link 22 to rotate around the first link 21, thereby driving the third link 23, the fourth link 24, the fifth link 25 and the distal phalanx 30 to move synchronously until the distal phalanx 30 contacts the object. At this time, the distal phalanx 30 of the two gripping components with opposite installation directions jointly perform parallel fingertip gripping and pinching of the object. During the movement, the fourth link 24 and the distal phalanx 30 translate and keep the fourth link 24 parallel to the first link 21, while the angle between the second link 22 and the third link 23 remains unchanged.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A gripping adaptive mechanical finger, characterized in that, include: A base (10) and a gripping assembly disposed on the base (10), the gripping assembly including a proximal phalanx (20) and a distal phalanx (30); the proximal phalanx (20) includes a first link (21), a second link (22), a third link (23), a fourth link (24), and a fifth link (25) that are rotatably connected end to end in a ring; the position where the first link (21) and the fifth link (25) are connected is fixedly connected to the base (10); the second link (22) is connected to a driver, the driver driving the second link (22) to rotate; a spring (26) is provided between the second link (22) and the third link (23); the fourth link (24) is parallel to the first link (21), and the distance between the two connection points of the fourth link (24) is the same as the distance between the two connection points of the first link (21); the distal phalanx (30) is fixedly connected to the fourth link (24); One end of the first link (21) is connected to one end of the base (10), and the other end of the first link (21) is away from the first link (21); one end of the distal phalanx (30) is fixedly connected to the fourth link (24), and the other end of the distal phalanx (30) is away from the first link (21). The angle between the first link (21) and the base (10) is any value between 90° and 270°, and the angle between the distal phalanx (30) and the fourth link (24) is greater than 0° and less than 180°.

2. The gripping adaptive mechanical finger according to claim 1, characterized in that, The angle between the first link (21) and the base (10) is 180°, and the angle between the distal phalanx (30) and the fourth link (24) is 90°.

3. The gripping adaptive mechanical finger according to claim 1, characterized in that, The initial angle between the second link (22) and the third link (23) is any value between 0° and 180°.

4. The gripping adaptive mechanical finger according to claim 3, characterized in that, A limiter is provided at the connection position between the second link (22) and the third link (23) to limit the initial angle between the second link (22) and the third link (23) from decreasing under the action of the spring (26).

5. A robotic hand based on the grasping adaptive mechanical finger according to any one of claims 1 to 4, characterized in that, The base (10) is provided with at least two gripping components, and the two gripping components are installed in opposite directions.

6. A grasping method based on the robotic arm according to claim 5, characterized in that, This includes envelope grasping and pinching / clamping. The envelope capture includes the following steps: S11: Place the object on the base (10); S12: The driver drives the second link (22) to rotate around the first link (21), thereby driving the third link (23), the fourth link (24), the fifth link (25) and the distal phalanx (30) to move synchronously until the fifth link (25) contacts the object. During the movement, the fourth link (24) and the distal phalanx (30) translate and keep the fourth link (24) parallel to the first link (21). The angle between the second link (22) and the third link (23) remains unchanged. S13: The driver drives the second link (22) to continue rotating around the first link (21). The angle between the second link (22) and the third link (23) gradually increases, the spring (26) is gradually stretched, and the distal phalanx (30) rotates with the fourth link (24) until the distal phalanx (30) contacts the object. At this time, the base (10), the fifth link (25) and the distal phalanx (30) of all gripping components together envelop and grip the object. The clamping and grasping process includes the following steps: S21: Place the object above the base (10); S22: The driver drives the second link (22) to rotate around the first link (21), thereby driving the third link (23), the fourth link (24), the fifth link (25) and the distal phalanx (30) to move synchronously until the distal phalanx (30) contacts the object. At this time, the distal phalanx (30) of the gripping components with opposite directions jointly perform parallel fingertip gripping of the object. During the movement, the fourth link (24) and the distal phalanx (30) translate and keep the fourth link (24) parallel to the first link (21), and the angle between the second link (22) and the third link (23) remains unchanged.

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