Mechanical finger, method of use, mechanical hand and robot

Abstract

The application discloses a mechanical finger, a use method, a mechanical hand and a robot, and relates to the technical field of robots. The mechanical finger comprises a plurality of sequentially hinged knuckles and a plurality of traction lines. Each knuckle is connected with at least one traction line. The knuckle connected with one traction line is referred to as the target knuckle of the traction line, and the remaining knuckles are referred to as non-target knuckles relative to the traction line. The traction line can independently pull and release the target knuckle. In the pulling state, the target knuckle rotates inward to a grasping state and remains in the grasping state. In the releasing state, the target knuckle is released from the grasping state. The use method of the mechanical finger comprises pulling a corresponding traction line to enable a corresponding knuckle to be in the grasping state and releasing the corresponding traction line to enable the corresponding knuckle to be in the releasing state. The mechanical hand comprises a palm and the use method of the mechanical finger. The robot comprises a robot body and the mechanical hand. The application can independently control the angle of any knuckle.

Description

Technical Field

[0001] This invention relates to the field of harvesting robot technology, and in particular to a mechanical finger, a method of use, a robotic hand, and a robot. Background Technology

[0002] Fruit and vegetable harvesting is the final stage of fruit and vegetable production and the beginning of commercial processing. The quality of harvesting directly affects the yield, quality, and shelf life of the product. Currently, automated harvesting is often achieved using robotic arms. A typical existing robotic finger employs a wire-driven structure, which usually includes a reel, a traction line, multiple finger joints, and joints between adjacent finger joints. The traction line is wound on the reel, and the ends of the traction line are sequentially connected to each joint until the most distal joint. By winding and unwinding the line on the reel, the joints are pulled to bend, thus achieving the grasping action of the finger. However, in this structure, the movement between the finger joints is coupled, meaning that all finger joints are driven in series by the same traction line. This results in each finger joint being able to bend sequentially according to a fixed time sequence, making it impossible to independently control the angle of any single finger joint. Summary of the Invention

[0003] The purpose of this invention is to provide a mechanical finger, a method of use, a robotic hand, and a robot to solve the problems existing in the prior art, and to independently control the angle of any finger joint.

[0004] To achieve the above objectives, the present invention provides the following solution: This invention provides a mechanical finger comprising multiple sequentially hinged phalanges; it includes multiple traction lines, each phalanx being connected to at least one traction line, the phalanx connected to a traction line being called the target phalanx of that traction line, and the remaining phalanges relative to that traction line being called non-target phalanges; the traction lines can independently pull and release the target phalanx; in the pulling state, the target phalanx rotates inward to a grasping state and maintains the grasping state; in the releasing state, the target phalanx releases the grasping state.

[0005] In one embodiment, each of the target phalanges rotates inward around its respective rotation axis to the grasping state while in a pulling state; each of the traction lines extends from the target phalanges, through the inside of the rotation axis of the target phalanges, toward the drive mechanism.

[0006] In one embodiment, a pivot is also included, through which the proximal end of the target phalanx is hinged to an adjacent phalanx or palm, the pivot being a target pivot for the target phalanx, and each of the traction lines passes inside the target pivot so that the traction line passes inside the rotation axis of the target phalanx.

[0007] In one embodiment, each of the knuckles is connected to only one of the traction lines; each of the shafts is fitted with a first guide wheel, and the traction line passes around the inside of the first guide wheel on the target shaft.

[0008] In one embodiment, the traction line passes over the inside of the corresponding first guide wheel and through the interior of the non-target phalanx on the proximal side of the traction line.

[0009] In one embodiment, the traction line bypasses the outside of the shaft on the proximal side of the target shaft.

[0010] In one embodiment, a reset element is further included, the reset force of which is used to restore the knuckle to its initial extended state in the released state.

[0011] The present invention also provides a method of using a mechanical finger, wherein the mechanical finger described above is used to: pull the corresponding traction line to put the corresponding phalanx into a grasping state; and release the corresponding traction line to put the corresponding phalanx into a releasing state.

[0012] The present invention also provides a robotic hand, including a palm and the aforementioned robotic fingers, wherein the robotic fingers are disposed on the palm.

[0013] The present invention also provides a robot, including a robot body and the aforementioned manipulator.

[0014] The present invention achieves the following technical effects compared to the prior art: This invention discloses a mechanical finger, a method of use, a robotic hand, and a robot. Each traction line individually controls one finger joint. By adjusting the tension of each traction line, the bending degree of the corresponding target finger joint can be independently controlled. The target finger joint rotates inward to a grasping state and maintains this grasping state. When bending a target finger joint is no longer needed, simply release the corresponding traction line, and the target finger joint releases its grasping state. This structure enables individual and flexible control of each target finger joint. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a structural schematic diagram of one embodiment of the mechanical finger in Example 1; Figure 2This is a structural schematic diagram of one embodiment of the robotic hand in Example 3; Figure 3 This is a diagram showing the traction wire winding of the distal phalanx in one embodiment of the mechanical finger of Example 2. Figure 4 This is a diagram showing the traction wire winding of the middle phalanx in one embodiment of the mechanical finger of Example 2. Figure 5 This is a diagram showing the traction wire winding of the proximal phalanx in one embodiment of the mechanical finger of Example 2. Figure 6 A simplified diagram illustrating the drive mechanism of the distal phalanx, intermediate phalanx, and proximal phalanx in one embodiment of the mechanical finger of Example 2; Figure 7 A simplified diagram of the distal phalanx driving one embodiment of the mechanical finger in Example 2; Figure 8 A simplified diagram of the drive mechanism of the middle phalanx in one embodiment of the mechanical finger of Example 2; Figure 9 A simplified diagram of the proximal phalanx driving one embodiment of the mechanical finger in Example 2; Figure 10 This is a schematic diagram of the drive mechanism of one embodiment of the mechanical finger in Example 1; Figure 11 This is a structural schematic diagram of one embodiment of the robotic hand in Example 3, where the robotic fingers are in a grasping state; In the diagram: 1. Finger; 2. Palm; 3. Drive mechanism; 301. Mounting base; 302. Winding reel; 303. Servo motor; 101. Knuckle; 1011. Distal knuckle; 1012. Middle knuckle; 1013. Proximal knuckle; 102. Second guide wheel; 103. First guide wheel; 104. Reset element; 105. Shaft; 106. Traction line; 1071. First traction line; 1072. Second traction line; 1073. Third traction line. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The purpose of this invention is to provide a mechanical finger, a method of use, a robotic hand, and a robot to solve the problems existing in the prior art, and to independently control the angle of any finger joint.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Example 1 like Figure 1-2 As shown, this embodiment provides a mechanical finger, including multiple sequentially hinged phalanges 101 and multiple traction lines 106. Each phalange 101 is connected to at least one traction line 106. The phalange 101 connected to one traction line 106 is called the target phalange of that traction line 106, and the other phalanges 101 relative to that traction line 106 are called non-target phalanges. The traction lines 106 can independently pull and release the target phalange. In the pulling state, the target phalange rotates inward to a grasping state and remains there. In the releasing state, the target phalange releases the grasping state.

[0021] Each traction line 106 individually controls one finger joint. By adjusting the tension of each traction line 106, the bending degree of the corresponding target finger joint can be independently controlled. The target finger joint rotates inward to a gripping state and maintains that gripping state. When it is no longer necessary to bend a target finger joint, simply release the corresponding traction line 106, and the target finger joint will release from the gripping state. This structure enables individual and flexible control of each target finger joint.

[0022] In one specific implementation, the target phalanx in the mechanical finger 1 can grasp fruits and vegetables in a grasping state, and can continuously grasp fruits and vegetables while maintaining the grasping state. The fruits and vegetables can be strawberries, apples, etc.

[0023] In one embodiment, each target finger joint rotates inward around its respective rotation axis to a gripping state while in a pulling state; each traction line 106 extends from the target finger joint, through the inside of the rotation axis of the target finger joint, toward the drive mechanism 3.

[0024] By extending the traction line 106 from the target finger joint through the inside of the rotation axis to the drive mechanism 3, a bending driving torque is provided to the target finger joint, so that each target finger joint can stably rotate inward around its respective rotation axis and enter the gripping state in the pulling state.

[0025] In one embodiment, a pivot 105 is also included, through which the proximal end of the target phalanx is hinged to an adjacent phalanx 101 or the palm 2. The pivot 105 is the target pivot of the target phalanx, and each traction line 106 passes through the inside of the target pivot so that the traction line 106 passes through the inside of the rotation axis of the target phalanx.

[0026] The target pivot provides a definite rotation center and constraint surface for the target phalanx, avoiding the swaying and slippage that may occur when relying solely on a flexible or virtual axis. This allows the target phalanx to rotate strictly inward around a fixed axis when being pulled, making the gripping action more precise and reliable.

[0027] In one embodiment, a knuckle 101 is connected to only one traction line 106; each shaft 105 is fitted with a first guide wheel 103, and the traction line 106 passes around the inside of the first guide wheel 103 on the target shaft 105.

[0028] One target knuckle corresponds to one traction line 106 and one target shaft 105. The target shaft 105 is provided with a first guide wheel 103 for the traction line 106. The first guide wheel 103 is used to guide the traction line 106. The first guide wheel 103 can precisely limit the direction and lever arm of the traction line 106, so that it always maintains the optimal tangential distance with the axis of the target shaft 105 during the rotation of the target knuckle, thereby ensuring stable and maximized driving torque and avoiding slippage or deviation of the traction line 106 that causes fluctuations in gripping force.

[0029] In one embodiment, the traction line 106 passes over the inside of the corresponding first guide wheel 103 and through the interior of the non-target phalanx on the proximal side of the traction line 106.

[0030] The proximal side refers to the side closer to the drive mechanism 3, while the distal side refers to the side farther away from the drive mechanism 3.

[0031] The traction cable 106 passes through the interior of the non-target phalanx on the proximal side, preventing the traction cable 106 from being exposed on the surface of the phalanx 101. This prevents it from getting tangled, hooked, or worn with external objects, improving the system's safety, cleanliness, and environmental adaptability. At the same time, the internal wiring constrains the path of the traction cable 106 throughout its entire length, reducing the movement or offset of the traction cable 106 caused by the movement of the phalanx 101. This further improves the transmission accuracy and response consistency, and facilitates the independent driving and coordinated control of each phalanx 101 in a multi-phalanx 101 series structure.

[0032] In one embodiment, the traction line 106 passes around the outside of the shaft 105 on the proximal side of the target shaft 105, so that the non-target phalanx on the proximal side of the traction line has an extending torque, thereby compensating for the additional effect of the traction line on the non-target phalanx by pulling the traction line connected to the non-target phalanx.

[0033] For ease of understanding, assume that the traction line 106 passes around the inside of the shaft near the target shaft and the torque applied to the non-target phalanx is inward. Since the torque applied to the non-target phalanx is also inward when it becomes the target phalanx of other traction lines, the two torques are in the same direction, and it is impossible to maintain the original extended state of the phalanx through compensation.

[0034] It also includes a second guide wheel 102, which is disposed on the shaft 105 near the target shaft 105. The traction line 106 connected to the target phalanx passes around the first guide wheel 103 and continues to pass around the outside of the second guide wheel 102. The second guide wheel 102 is used to guide the traction line 106. The diameter of the second guide wheel 102 is the same as that of the first guide wheel 103, which makes it easy to calculate the torque of a phalanx 101 under the drive of different traction lines 106, and then calculate the magnitude of the applied force as needed.

[0035] In one specific embodiment, the first guide wheel 103 and the second guide wheel 102 are both grooved bearings. The grooved bearings can be used to guide the traction line 106 and reduce the frictional loss of the traction line 106 during movement. During installation, positioning bushings are provided on both sides of the first guide wheel 103 and the second guide wheel 102 to axially limit the grooved bearings and ensure that the traction line 106 moves stably within the designed path.

[0036] In one embodiment, a reset element is also included, the reset force of which is used to restore the phalanx 101 to its initial extended state in the released state.

[0037] In the released state, the reset element can provide a restoring torque to the corresponding phalanx 101, causing the finger 1 to automatically open, that is, tend to straighten.

[0038] In one specific embodiment, the reset element can be a torsion spring. The reset element passes through the rotating shaft 105, and its two ends are fixedly connected to adjacent knuckles 101. The reset element located between the knuckle 101 and the palm 2 is fixedly connected to the knuckle 101 and the palm 2 respectively. When the knuckle 101 rotates around the rotating shaft 105 and is pulled inward by the traction line 106, the torsion spring is twisted and stores energy. When the driving force is removed, the traction line 106 is released, the torsion spring releases energy, and the knuckle 101 automatically returns to its initial position, i.e., the extended state. The torsion spring is coaxially mounted on the rotating shaft 105, without occupying additional internal or external space of the knuckle 101, which is beneficial for miniaturization and weight reduction of the knuckle 101.

[0039] Example 2 This embodiment discloses a method of using a mechanical finger. According to the mechanical finger of Embodiment 1, the corresponding traction line 106 is pulled to make the corresponding knuckle 101 put into a grasping state; the corresponding traction line 106 is released to make the corresponding knuckle 101 put into a releasing state.

[0040] The gripping and releasing of the corresponding knuckle 101 can be directly controlled by a single action of pulling or releasing the traction line 106, which is simple to operate and responds quickly.

[0041] In some embodiments, the traction line 106 passes over the inside of the corresponding first guide wheel 103 and through the interior of the non-target phalanx on the proximal side of the traction line 106.

[0042] Since the traction line 106 passes through the inside of the corresponding first guide wheel 103 and passes through the non-target phalanx on the proximal side, when the mechanical finger provided in this embodiment is used and the target phalanx is pulled, it will generate an additional torque effect on the non-target phalanx through which the traction line connected to the target phalanx passes. Therefore, it is necessary to connect the non-target phalanx to other traction lines and apply an additional torque to compensate for the additional torque on the non-target phalanx.

[0043] The steps for compensating for the additional torque on non-target phalanges are as follows: The required state and stroke of the traction line for compensating the additional torque are determined in advance through torque balance relationships and kinematic calculations; then, the additional torque for compensating the finger joint is controlled according to the required state and stroke. The specific calculation steps for the state and stroke of the traction line required to compensate for the additional torque are as follows: To make it easier to understand, let's take a specific example with three phalanges as an example. Figure 3-5 As shown, the phalanx 101 is divided into three segments: the distal phalanx 1011, the intermediate phalanx 1012, and the proximal phalanx 1013. The distal phalanx 1011 corresponds to the first traction line 1071, the intermediate phalanx 1012 corresponds to the second traction line 1072, and the proximal phalanx 1013 corresponds to the third traction line 1073. Figure 6-9 The following is a simplified diagram of the three-knuckle finger drive. Based on this simplified diagram, the relationship between the driving force of the traction line 106 and the closing torque of the knuckle 101 is established: ; ; In the formula, , , These are the closing torques of the distal phalanx 1011, the intermediate phalanx 1012, and the proximal phalanx 1013, respectively. , , The driving forces generated by the first traction line 1071, the second traction line 1072, and the third traction line 1073 are respectively. , , These are the equivalent restoring forces of the reset element converted to the corresponding driving direction, respectively; r is the equivalent winding radius.

[0044] Furthermore, the incremental traction line travel of the distal phalanx 1011, intermediate phalanx 1012, and proximal phalanx 1013 satisfies the following relationship with the incremental joint angle: ; ; ; In the formula, , , These are the travel increments for the first traction line 1071, the second traction line 1072, and the third traction line 1073, respectively. , , These are the joint angle increments for the distal phalanx, intermediate phalanx, and proximal phalanx, respectively. The center distance between the pivot points of the distal and intermediate phalanges. It is the center distance between the pivot points of the middle phalanx and the proximal phalanx.

[0045] The formula can be used to further obtain the mapping relationship between the traction line stroke increment and the joint angle increment.

[0046] in, ; Since the mapping matrix T is a non-singular matrix, a reversible mapping relationship can be established between the stroke increment of the traction line 106 and the joint angle increment. Under the combined action of the restoring torque provided by the reset element and the traction torque provided by the traction line 106, each phalanx 101 can achieve relatively independent bending and reset actions. Therefore, this invention possesses the ability to actively control the posture of each phalanx 101, enabling the bend of multiple phalanxes 101 during grasping to form a wrapping posture adapted to the shape of the target fruit, thus improving the harvester's adaptability.

[0047] Therefore, when the first traction line 1071 is tightened, the distal phalanx 1011 is subjected to a bending driving torque and bends. Since the first traction line 1071 is arranged across multiple phalanges 101 within the finger 1, its tensioning process generates additional torque on the intermediate phalanx 1012 and proximal phalanx 1013, resulting in undesirable movement tendencies in adjacent phalanges 101. To eliminate the influence of the additional torque on the movement of the intermediate phalanx 1012, a second traction line 1072 is provided. The second traction line 1072 passes through the corresponding first guide wheel 103 and connects to the intermediate phalanx 1012 to provide a bending driving torque to the intermediate phalanx 1012. By adjusting the tension of the second traction line 1072, the additional influence of the first traction line 1071 on the intermediate phalanx 1012 can be compensated, while simultaneously achieving active bending adjustment of the intermediate phalanx 1012. Similarly, the third traction line 1073, after passing through the first guide wheel 103 at the corresponding position, connects to the proximal phalanx 1013 to provide a bending driving torque to the proximal phalanx 1013. Through the coordinated action of the first traction line 1071, the second traction line 1072, and the third traction line 1073, the distal phalanx 1011, the intermediate phalanx 1012, and the proximal phalanx 1013 each obtain their respective driving torques, thereby improving the flexibility of the multi-joint finger 1 in posture adjustment.

[0048] Example 3 like Figure 1-10 As shown, this embodiment discloses a robotic hand, including a palm 2 and robotic fingers as described in Embodiment 1, with robotic fingers 1 disposed on the palm 2.

[0049] Under different fruit and vegetable harvesting conditions, the overall shape of the hand 2 can be adjusted according to the size of the target fruit and vegetable, the density of fruit clusters, the shading of branches and leaves, and the installation space at the end of the robotic arm. Specifically, the length and width of the hand 2, the installation spacing of the fingers 1, the installation position of the drive mechanism 3, and the routing path of the traction line 106 can all be adaptively designed according to the actual work object and installation space. For example, when it is necessary to place the drive mechanism 3 in a position away from the fruit contact area, the length of the hand 2 can be appropriately increased to create a certain distance between the drive mechanism 3 and the fingers 1, thereby reducing the interference of the drive mechanism 3 on the fruit approach and grasping process.

[0050] In one specific embodiment, the drive mechanism 3 includes a winding reel 302, a power source, and a fixed base 301. The winding reel 302 is used to wind and release the traction line 106. The winding reel 302 is installed at the output end of the power source, and the power source drives the winding reel 302 to rotate in both directions. The power source is installed on the fixed base 301.

[0051] The drive mechanism 3 includes multiple power sources such as servo motors 303 and their corresponding winding reels 302. Each servo motor 303 independently controls the forward and reverse rotation of a winding reel 302, thereby winding or releasing the corresponding traction line 106 to drive the corresponding knuckle 101 to produce bending or extending movements. By adjusting the rotation angle and torque of each servo motor 303, the stroke and tension of each traction line 106 can be precisely controlled, thereby achieving coordinated posture control of the multi-joint fingers 1. The surface of the winding reel 302 is provided with anti-slip grooves, and the traction line 106 is embedded in the grooves, effectively reducing slippage during winding and releasing, and improving transmission accuracy and reliability. In addition, by adjusting the initial installation angle of the winding reel 302 or the initial zero position of the servo motor 303, a preload can be applied to the traction line 106 to keep it in a proper tension state, avoiding transmission lag or decreased control accuracy due to cable slack. This structure can reduce the volume and weight of the end effector area while maintaining the multi-joint posture adjustment capability, improving the harvester's accessibility and operational flexibility in confined spaces.

[0052] For example, in harvesting fruits and vegetables such as tomatoes, kiwis, and citrus fruits, which are relatively large and nearly spherical or ellipsoidal in shape, the width of the palm 2 and the spacing between the fingers 1 can be appropriately increased. This allows the fingers to approach the fruit from different directions, and the coordinated bending of the distal phalanx 1011, intermediate phalanx 1012, and proximal phalanx 1013 creates a larger area of ​​covering contact, thereby improving grasping stability. In harvesting fruits such as cherry tomatoes, grapes, and blueberries, which are smaller and often grow in clusters, the size of the front end of the palm 2 can be appropriately reduced. The spacing between the fingers 1 and the arrangement of the drive mechanism 3 on the back of the palm 2 or away from the fruit contact area allow the fingers to enter between fruits or areas obstructed by branches and leaves for grasping, reducing the possibility of interference between the drive mechanism such as the servo motor 303 and the winding reel 302 and adjacent fruits, stems, or branches and leaves. In harvesting fruits and vegetables such as cucumbers and peppers that are longer or have significant changes in posture, the length of the palm 2 and the bending angle of each finger joint can be adjusted according to the fruit length and spatial posture, allowing the multi-jointed fingers to form segmented contact along the outer surface of the fruit. Therefore, this invention can be structurally adapted to different fruits and vegetables in terms of size, shape, cluster density, and foliage obstruction, improving the applicability of the line-driven multi-jointed fruit and vegetable harvester in various harvesting objects and complex working spaces.

[0053] Example 4 This embodiment discloses a robot, including a robot body and the aforementioned robotic arm.

[0054] The robot body is equipped with a robotic arm for grasping tasks. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention; furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A mechanical finger, comprising a plurality of sequentially hinged phalanges; characterized in that: include: Multiple traction lines are provided, and each finger joint is connected to at least one traction line. The finger joint connected to a traction line is called the target finger joint of that traction line, and the other finger joints are called non-target finger joints relative to that traction line. The traction lines can independently pull and release the target finger joint, and the traction lines have a pulling state and a releasing state. In the pulling state, the target finger joint rotates inward to a grasping state and maintains the grasping state; In the released state, the target phalanx is released from the grasping state.

2. The mechanical finger according to claim 1, characterized in that: Each of the target phalanges rotates inward around its respective axis of rotation to the grasping state while in the pulling state; each of the traction lines extends from the target phalange, through the inner side of the rotation axis of the target phalange, toward the drive mechanism.

3. The mechanical finger according to claim 2, characterized in that: It also includes a pivot, through which the proximal end of the target phalanx is hinged to an adjacent phalanx or palm. The pivot is the target pivot of the target phalanx, and each of the traction lines passes inside the target pivot so that the traction line passes inside the rotation axis of the target phalanx.

4. The mechanical finger according to claim 3, characterized in that: Each of the finger joints is connected to only one of the traction lines; each of the shafts is fitted with a first guide wheel, and the traction line passes around the inside of the first guide wheel on the target shaft.

5. The mechanical finger according to claim 4, characterized in that: The traction line passes over the inside of the corresponding first guide wheel and through the inside of the non-target phalanx on the proximal side of the traction line.

6. The mechanical finger according to claim 5, characterized in that: The traction line passes around the outside of the target shaft near its proximal end.

7. The mechanical finger according to claim 1, characterized in that: It also includes a reset element, the reset force of which is used to restore the knuckle to its initial extended state in the released state.

8. A method of using a mechanical finger, characterized in that: The mechanical finger according to any one of claims 1-7; Pull the corresponding traction line to put the corresponding knuckle into a grasping state; Release the corresponding traction line to put the corresponding knuckle in the released state.

9. A robotic arm, characterized in that: It includes a palm and a mechanical finger as described in any one of claims 1-7, wherein the mechanical finger is disposed on the palm.

10. A robot, characterized in that: It includes the robot body and the robotic arm as described in claim 9.

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