A string tomato picking end effector and picking method thereof

Abstract

The present application provides a kind of string tomato picking end effector and its picking method.The string tomato picking end effector is installed on the picking mechanical arm end flange;Depth camera is fixed above picking end effector, for capturing picking scene image, through deep learning identification algorithm, obtain string tomato fruit stem picking point position information, control system guide mobile manipulator to specified position, execute picking action;String tomato picking end effector is composed of rail, switch door, blade, push head, pipe base, push rod, pipe sliding table, push rod motor, push rod motor seat, motor limit switch, slider, push rod limit switch support, push rod limit switch, slide rail, bottom plate, support, compression spring and clamping jaw table, wherein clamping jaw table is composed of clamping jaw, DC speed reducer, motor limit switch, L connection, motor support, clamping jaw table base.This application adopts the structure of shear and clamp, improves the picking efficiency and success rate of string tomato.

Description

Technical Field

[0001] This invention belongs to the field of modern agricultural equipment technology, and relates to automated fruit and vegetable harvesting technology, and in particular to a tomato harvesting end effector and its harvesting method. Background Technology

[0002] The application of automated fruit and vegetable harvesting technology in agriculture is becoming increasingly widespread, with the main goals of improving production efficiency, reducing labor costs, and alleviating labor shortages. Tomatoes, as an important vegetable product, are widely cultivated, but traditional harvesting relies on manual labor, which faces numerous problems such as high labor costs, low production efficiency, high work intensity, and easy damage to the fruit. Therefore, there is an urgent need to develop an efficient, precise, and stable automated tomato harvesting technology to improve fruit quality and yield.

[0003] While harvesting robots have been developed and designed for various fruits, their success rate and speed are still affected by the fruit's growth posture. There is a need to design simpler, smaller end effectors to handle fruits in complex growing environments, while ensuring harvesting success and fruit integrity, thereby improving the robot's flexibility and applicability. Simultaneously, cost reduction is crucial to increase the widespread adoption of harvesting robots. The current use of multiple end effectors for different fruits lacks universality, leading to high costs and maintenance difficulties for orchards with various fruits and vegetables. A single end effector needs to be designed for fruits and vegetables with similar harvesting methods. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this invention is to propose a tomato harvesting end effector and a tomato harvesting method that integrates shearing and clamping. This method minimizes damage to the target fruit and surrounding fruits, even when fruits are stacked or obstructed. It enables autonomous tomato harvesting, resulting in orderly stacking of harvested tomatoes, thus improving harvesting efficiency and adaptability to tomatoes of different sizes and shapes.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a tomato picking end effector, characterized in that it is mounted on the wrist flange of a tomato picking robot by means of a bracket (21), and the spatial position of the picking object is obtained by a depth camera (23) above the bracket (21) and a control system.

[0006] The depth camera (23) is fixed to the bracket (21) by screws. It is used to collect images of the picking scene and send them to the control system. The control system calculates the spatial position of the picking object and controls the robotic arm to reach the designated position. Then, it drives the end effector of the bunch of tomatoes to perform the relevant picking action.

[0007] The tomato picking end actuator includes the railing (1), the opening and closing door (2), the blade (3), the push head (4), the tube seat (5), the push rod (6), the push rod motor (11), the push rod motor seat (12), the slider (16), the push rod limit switch (17), the push rod limit switch support (18), the slide rail (19), the base plate (20), the bracket (21), the compression spring (22), and the gripper platform;

[0008] The tube seat (5) is fixedly installed above the base plate (20) by screws. The railing (1) is fixedly installed above the tube seat (5) by screws. The switch door (2) is fixedly installed at the end of the railing (1) by screws and a cylindrical torsion spring (24) for axial positioning. The blade (3) is installed above the push head (4) by screws. The push rod (6) passes through the tube seat (5) and is fixedly installed on the push head (4) by screws. The compression spring (22) passes through the push rod (6) and limits the distance between the push head (4) and the tube seat (5). The other end of the push rod (6) passes through the tube slide (7) and is fixedly installed by screws. The tube slide (7) is fixedly installed on the tube seat (5) by screws. Above the slider (16), the slider (16) slides back and forth along the slide rail (19), the slide rail (19) is fixed to the base plate (20) by screws; the push rod motor seat (12) is fixed to the base plate (20) by screws, the push rod motor (11) is fixedly installed inside the push rod motor seat (12), and the other end of the push rod motor (11) is fixedly installed on one side of the L connection (10) by screws; the push rod limit switch support (18) is installed on the base plate (20) by screws, and the push rod limit switch (17) is fixedly installed on one side of the push rod limit switch support (18) by screws;

[0009] The gripper platform includes grippers (8), DC geared motors (9), L-connectors (10), gripper platform base (13), motor brackets (14), and motor limit switches (15). The gripper platform base (13) is fixed to the base plate (20) with screws, and the motor brackets (14) are fixed to the gripper platform base (13) with screws. The L-connectors (10) are fixed to the gripper platform base (13) with screws, and the other end is fixed to the push rod motor (11) with screws. The two DC geared motors (9) are vertically installed and fixed inside the motor brackets (14), and the grippers (8) are fixedly installed through the DC geared motors (9). The two motor limit switches (15) are fixed to the gripper platform base (13) with screws.

[0010] Optionally: The front end of the railing (1) has a protrusion to limit the opening and closing of the door (2).

[0011] Optionally: the railings (1) are installed on the tube base (5) in a centrally symmetrical distribution, and the two railings have the same assembly scheme.

[0012] Optionally, the blade (3) extends relative to the pusher (4) to ensure that the door (2) can contact the pusher (4).

[0013] Optionally, the compression spring (22) provides axial restraint between the switch door (2) and the tube seat (4).

[0014] Optionally, the two left and right grippers (8) can clamp the tube slide (7) for axial positioning.

[0015] Optionally: the push rod motor (11) is fixed on the push rod motor seat (12), the extended end of the push rod motor (11) limits the L connection (10), and the L connection (10) can limit the gripper table axially.

[0016] Optionally, the push rod limit switch support (18) and the push rod limit switch (17) together axially limit the motor bracket (14).

[0017] A method for picking cherry tomatoes, the method comprising the following steps: S1, a depth camera (23) above a support (21) detects a cherry tomato bunch that can be picked, stops moving in front of the target cherry tomato bunch, the control system obtains the target position information of the target cherry tomato bunch through image recognition and positioning, and drives the robotic arm to move the end effector of the cherry tomato bunch to the front of the target, so that the fruit stalk of the target cherry tomato bunch pushes open the switch door (2) and enters the picking area, the switch door (2) closes under the action of the cylindrical torsion spring (24), leaving the fruit stalk of the cherry tomato bunch inside the switch door (2);

[0018] S2. When the DC geared motor (9) is working, the gripper (8) rotates counterclockwise with the motor shaft of the DC geared motor (9) to open and close the tube slide (7). A limit switch (15) is installed on the outer side of each of the two grippers (8). After the gripper (8) reaches the outer limit position, it continues to rotate and locks itself. The push rod (6) moves forward under the drive of the compression spring (22). The blade (3) installed on the push head (4) at the front end of the push rod (6) cuts the fruit stem under the thrust of the compression spring (22). The lower end of the blade (4) with the blade (3) and the switch door (2) form a clamping device to clamp the fruit stem.

[0019] S3. The push rod motor (11) moves forward. After the gripper table (13) touches the push rod limit switch (17), the push rod motor (11) stops extending. The DC geared motor (9) controls the gripper (8) to rotate clockwise and clamp the tube slide table (7) at the end of the push rod (6). Then the push rod motor (11) moves backward, and the push head (4) also moves backward. The opening and closing door (2) and the push head (4) release the fruit stalk, and the fruit bunch falls into the fruit collection device to carry out the fruit collection operation.

[0020] S4. Wait for the depth camera (23) to find the next bunch of fruit to be picked, and then carry out the picking operation again.

[0021] The beneficial effects of this invention are as follows:

[0022] 1. This invention adopts an integrated shear and clamp design. Compared with the traditional shear type, it does not require such high installation and recognition accuracy. It has a compact structure, is easy to control, and is highly adaptable to various environments.

[0023] 2. During the cutting process, traditional end effector cutting mechanisms easily damage the target fruit and surrounding fruits, and the fruits may overlap and obstruct each other, making harvesting difficult. This invention keeps the fruit stem within a safe range during cutting, preventing the blade from damaging surrounding fruit clusters.

[0024] 3. This invention cuts off the fruit stem while clamping it with a clamping mechanism, and is designed with a resistance groove to increase the friction of the clamping structure, further ensuring stable clamping.

[0025] 4. This invention adopts a modular approach, with each individual module assembled without interference. Unlike traditional end effectors, each module is easy to disassemble, repair, and replace. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a tomato harvesting end effector provided by the present invention;

[0028] Figure 2 An exploded view of a tomato harvesting end effector provided by the present invention;

[0029] Figure 3This is a flowchart illustrating a tomato harvesting method provided by the present invention.

[0030] Legend: 1. Railing; 2. Door switch; 3. Blade; 4. Push head; 5. Pipe seat; 6. Push rod; 7. Pipe slide; 8. Gripper; 9. DC geared motor; 10. L-connector; 11. Push rod motor; 12. Push rod motor seat; 13. Gripper base; 14. Motor bracket; 15. Motor limit switch; 16. Slider; 18. Push rod limit switch support; 17. Push rod limit switch; 19. Slide rail; 20. Base plate; 21. Bracket; 22. Compression spring; 23. Depth camera. Detailed Implementation

[0031] The technical solutions will now be clearly and completely described with reference to the accompanying drawings of the embodiments in this application. It should be understood that the embodiments described are only some examples of this application, and not all of them. All other embodiments obtained by those skilled in the art based on these embodiments of this application without inventive work are protected within the scope of this application.

[0032] This invention proposes a terminal actuator and harvesting method for picking bunch tomatoes. The invention will be further described below with reference to the accompanying drawings and specific implementation.

[0033] like Figure 1 As shown, the present invention discloses a tomato harvesting end effector, which is mounted on the wrist flange of a harvesting robot via a bracket 21. The spatial position of the harvested fruit is acquired through a depth camera 23 and a control system. The depth camera 23 is fixed to the bracket 21 with screws. A deep learning image recognition algorithm is used to convert the image captured by the camera into accurate fruit location information and determine the optimal harvesting point. Then, the robotic arm carries the end effector to the target position to begin harvesting.

[0034] like Figure 1 and Figure 2 As shown, the end effector for picking tomatoes includes a railing 1, a door 2, a blade 3, a pusher 4, a tube seat 5, a push rod 6, a tube slide 7, a DC geared motor 9, an L-connector 10, a push rod motor 11, a push rod motor seat 12, a motor bracket 14, a motor limit switch 15, a slider 16, a push rod limit switch support 18, a push rod limit switch 17, a slide rail 19, a base plate 20, a bracket 21, a compression spring 22, a depth camera 23, and a gripper table.

[0035] The DC geared motor 9 is fixedly installed inside the motor bracket with screws. The motor shaft of the DC geared motor 9 is connected to the gripper 8 by an interference fit. The motor limit switch 15 provides radial limit for the gripper 8. The push rod motor 12 is fixed to the push rod motor base 12 with screws. The motor shaft of the push rod motor 12 is connected to the L-connector 10 with screws for axial positioning. The L-connector 10, the motor bracket 14, and the motor limit switch 15 are fixed to the gripper platform base 13 with screws. The gripper platform base is fixed to the slider 16 with screws. The slide rail 19 provides radial limit for the slider 16.

[0036] like Figure 2 As shown, the gripper table includes grippers 8, DC geared motors 9, L-connectors 10, a gripper table base 13, a motor bracket 14, and motor limit switches 15. The gripper table base 13 is fixed to the base plate 20 with screws, and the motor bracket 14 is fixed to the gripper table base 13 with screws. The L-connector 10 is fixed to the gripper table base 13 with screws, and its other end is fixed to the push rod motor 11 with screws. The two DC geared motors 9 are vertically mounted and fixed inside the motor bracket 14, and the grippers 8 are fixedly mounted via the DC geared motors 9. The two motor limit switches 15 are fixed to the gripper table base 13 with screws.

[0037] Figure 1 and Figure 2 As shown, the switch door 2 passes through the railing 1 with screws and is kept closed by the cylindrical torsion spring 24. The railing 1 is axially limited by the protrusion at the front end. The push head 4 is installed at the front end of the push rod 6. The compression spring 22 passes through the push rod 4 and is located between the push head 4 and the tube seat 5 for axial limitation. The push head 4, the railing 1 and the switch door 2 together form a clamping mechanism.

[0038] The push rod limit switch 17 and the motor limit switch 15 limit the initial position of the actuator.

[0039] The contact surfaces of the opening / closing door 2 and the pusher head 4 are provided with resistance grooves to increase the holding force. After the blade 3 cuts the fruit stem, it is clamped to facilitate the subsequent transportation of the fruit bunch to the fruit collection device.

[0040] like Figure 3 The workflow shown is as follows: S10, the depth camera 23 above the tomato picking end effector bracket 21 takes a picture of the front, and the image taken by the camera is converted into the accurate three-dimensional spatial coordinates of the fruit through a deep learning image recognition algorithm.

[0041] S11. The host computer obtains the three-dimensional spatial coordinates of the target fruit and controls the robotic arm to move the end effector toward the fruit stem. The tomato stem pushes open the switch door 2, and the stem enters the picking area. The switch door 2 closes under the action of the cylindrical torsion spring 24, trapping the stem inside the switch door 2.

[0042] S12. After receiving the instruction from the host computer, the Arduino microcontroller controls the DC geared motor 9 to work, driving the gripper 8 to rotate counterclockwise to open the release push rod. A limit switch 15 is installed on the outer side of both grippers 8 to prevent the grippers 8 from continuing to rotate and getting stuck when they reach the outer limit position. The end effector reaches the shearing state.

[0043] S13. The control of the two grippers 8 clamping inward is controlled by a Hall sensor installed at the tail of the motor. The push rod 6 moves forward under the drive of the compression spring 22. The blade 3 on the push head 4 installed at the front end of the push rod 6 cuts the fruit stem under the action of the compression spring 22. The lower part of the push head 4 with the blade 3 and the opening and closing door 2 form a clamping device to clamp the fruit stem.

[0044] S14. The robotic arm drives the end effector to the top of the fruit collection device. The host computer controls the microcontroller to drive the push rod motor 11 to work forward. After the gripper table 13 touches the push rod limit switch 18, the push rod motor 11 stops extending. The DC geared motor 9 works to control the gripper 8 to rotate clockwise and clamp the tube slide table 7 at the end of the push rod. Then the push rod motor 11 moves backward, the push head 4 moves backward, the clamping mechanism releases the fruit stalk, and the fruit bunch falls into the fruit collection device to carry out the fruit collection operation.

[0045] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A tomato harvesting end effector, characterized in that, The tomato picking robot is mounted on the wrist flange of the bracket (21), and the spatial position of the picking object is obtained by the depth camera (23) above the bracket (21) and the control system. The depth camera (23) is fixed to the bracket (21) by screws. It is used to collect images of the picking scene and send them to the control system. The control system calculates the spatial position of the picking object and controls the robotic arm to reach the designated position. Then, it drives the end effector of the tomato string to perform the relevant picking action. The tomato picking end actuator includes a railing (1), a door (2), a blade (3), a pusher (4), a tube seat (5), a push rod (6), a push rod motor (11), a push rod motor seat (12), a slider (16), a push rod limit switch (17), a push rod limit switch support (18), a slide rail (19), a base plate (20), a bracket (21), a compression spring (22), and a gripper platform; The tube seat (5) is fixedly installed above the base plate (20) by screws. The railing (1) is fixedly installed above the tube seat (5) by screws. The switch door (2) is fixedly installed at the end of the railing (1) by screws and a cylindrical torsion spring (24) for axial limiting. The blade (3) is installed above the push head (4) by screws. The push rod (6) passes through the tube seat (5) and is fixedly installed on the push head (4) by screws. The compression spring (22) passes through the push rod (6) and limits the distance between the push head (4) and the tube seat (5). The other end of the push rod (6) passes through the tube slide (7) and is fixedly installed by screws. The tube slide (7) is fixedly installed by screws. The screw is fixedly installed above the slider (16), the slider (16) slides back and forth along the slide rail (19), the slide rail (19) is fixed to the base plate (20) by screws; the push rod motor seat (12) is fixedly installed to the base plate (20) by screws, the push rod motor (11) is fixedly installed inside the push rod motor seat (12), and the other end of the push rod motor (11) is fixedly installed to one side of the L connection (10) by screws; the push rod limit switch support (18) is installed to the base plate (20) by screws, and the push rod limit switch (17) is fixedly installed to one side of the push rod limit switch support (18) by screws; The gripper platform includes grippers (8), a DC geared motor (9), the L-connector (10), a gripper platform base (13), a motor bracket (14), and a motor limit switch (15). The gripper platform base (13) is fixed to the base plate (20) with screws, and the motor bracket (14) is fixed to the gripper platform base (13) with screws. The L-connector (10) is fixed to the gripper platform base (13) with screws, and its other end is fixed to the push rod motor (11) with screws. Two DC geared motors (9) are vertically mounted and fixed inside the motor bracket (14), and the gripper (8) is fixedly mounted through the DC geared motors (9); two motor limit switches (15) are fixedly mounted on the gripper table base (13) by screws, and the push rod motor (11) is fixed on the push rod motor seat (12). The extended end of the push rod motor (11) limits the L-connection (10), and the L-connection (10) can axially limit the gripper table.

2. The end effector for picking bunch tomatoes according to claim 1, characterized in that: The front end of the railing (1) has a protrusion that limits the opening and closing of the door (2).

3. The end effector for harvesting bunch tomatoes according to claim 1, characterized in that: The railings (1) are installed on the tube base (5) in a centrally symmetrical distribution, and the two railings (1) have the same assembly scheme.

4. The end effector for picking bunch tomatoes according to claim 1, characterized in that: The blade (3) is longer than the pusher (4) to ensure that the door (2) can contact the pusher (4).

5. The end effector for harvesting bunch tomatoes according to claim 1, characterized in that: The compression spring (22) provides axial restraint between the switch door (2) and the tube seat (5).

6. The end effector for picking bunch tomatoes according to claim 1, characterized in that: The two grippers (8) on the left and right sides can clamp the tube slide (7) and limit its axial movement.

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