A tomato-harvesting robot with a flexible end effector and a harvesting method

Abstract

This invention relates to the field of tomato harvesting technology, specifically to a tomato harvesting robot and method equipped with a flexible end effector. The tomato harvesting robot with the flexible end effector has a ring-shaped conveying mechanism between its manipulator and its moving mechanism. An end effector is provided at the output end of the manipulator. The end effector includes flexible arms, with multiple flexible arms arranged in a circle along the axis of a drive cylinder to form a gripping space for holding the tomato fruit. When the piston rod of the drive cylinder is in a first position, the flexible arms bend inwards towards the gripping space, forming an enveloping grip on the tomato fruit. When the piston rod of the drive cylinder is in a second position, the flexible arms bend outwards towards the gripping space, thereby releasing the tomato fruit. This tomato harvesting robot with a flexible end effector improves upon the poor versatility of existing harvesting robots, reduces damage to the tomato fruit during harvesting, and enhances the quality of tomato harvesting.

Description

Technical Field

[0001] This invention relates to the field of tomato harvesting technology, specifically to a tomato harvesting robot and harvesting method equipped with a flexible end effector. Background Technology

[0002] Tomato harvesting is the most time-consuming and labor-intensive part of tomato production. Labor required during the tomato harvest accounts for approximately 50% to 70% of the entire planting process. To reduce labor input in tomato harvesting, existing technologies utilize agricultural robots for harvesting. However, tomato harvesting places high demands on these robots, requiring high harvesting precision to ensure quality. The quality of the harvest directly affects the storage, processing, and sales of tomatoes, ultimately influencing market prices and economic benefits. Due to the complexity of tomato harvesting, the level of automation in tomato fruit harvesting remains very low.

[0003] A search revealed a tomato-harvesting robot and its harvesting method in Chinese patent document CN116982478A. This tomato-harvesting robot reduces the free-fall motion of tomatoes and minimizes collisions through a buffer mechanism. Furthermore, the robot utilizes a vortex component to concentrate air in the middle of the buffer tube, simultaneously creating airflow that blows across the tomato surface, further reducing the tomato's falling speed and drop, thus minimizing the chance of injury.

[0004] However, in actual harvesting operations, the aforementioned tomato-harvesting robot's use of buffer mechanisms to protect the tomato fruits is far from sufficient. The harvested tomatoes still sometimes rot or become damaged. Tomato growth varies with time and space; the growing environment is dynamic, unpredictable, and open, directly influenced by natural conditions such as soil, season, and weather. The aforementioned tomato-harvesting robot lacks the handling capabilities appropriate for the tomato's delicate nature, lacks intelligent judgment, and cannot adapt to the unpredictable natural environment.

[0005] For example, Chinese patent document CN114902872A discloses a visual guidance method for robot fruit picking. This visual guidance method is based on a RealSense camera and comprehensively utilizes color and depth information to identify, segment, locate, and estimate the posture of fruit products, providing the robot with information on the optimal gripping posture for fruit picking operations. It also uses deep learning and 3D reconstruction technology to provide visual guidance for the fruit picking robot to autonomously find and pick fruits.

[0006] Although the aforementioned visual guidance method can theoretically guide the end effector of the harvesting robot to accurately reach the harvesting position, due to the complex shape of tomato fruits, their varying degrees of growth and development, and the significant differences between them, the end effector still finds it difficult to gently and accurately harvest the tomato fruits. The gripping and harvesting of the tomato fruits by the end effector can cause damage to the tomato fruits.

[0007] In addition, tomato harvesting robots typically operate and move simultaneously. Their movement doesn't involve the shortest distance between the starting point and the destination, but rather covers a narrow area, a relatively long distance, and spans the entire field surface. Furthermore, existing harvesting robots lack versatility; often, a single robot is only designed to complete a single harvesting task for a particular plant. Summary of the Invention

[0008] The purpose of this invention is to address the problems of low harvesting efficiency and low success rate of existing tomato harvesting equipment, particularly the inability of existing harvesting equipment to selectively harvest tomatoes, which are prone to damage and vary in size. This invention provides a harvesting device to improve the poor versatility of existing harvesting robots, reduce damage to tomatoes during harvesting, and improve the quality of tomato harvesting.

[0009] To achieve the above objectives, the present invention adopts the following solution:

[0010] On one hand, the present invention proposes a tomato harvesting robot with a flexible end effector, including a moving mechanism, an identification and positioning system and a robotic arm. The moving mechanism is used to move within the tomato planting area. The identification and positioning system is installed on the moving mechanism and is used to collect real-time image information of the tomato fruit and guide the moving mechanism to move within the tomato planting area. The robotic arm is used to grip and harvest the tomato fruit.

[0011] A ring conveying mechanism is provided between the robotic arm and the moving mechanism, and the fixed end of the robotic arm is connected to the moving mechanism through the ring conveying mechanism;

[0012] The annular conveying mechanism includes a support column, an annular track, a mechanical clamp, a power unit, and an adjusting frame. The annular track is mounted above the moving mechanism via the support column. The adjusting frame is mounted on the annular track and slides around the annular track. The power unit is mounted on the adjusting frame. The mechanical clamp is connected to the output end of the power unit. The power unit is used to drive the mechanical clamp to move along a sliding plane perpendicular to the annular track. The fixed end of the manipulator is mounted on the mechanical clamp.

[0013] The output end of the robotic arm is equipped with an end effector for gripping tomato fruits. The end effector includes a flexible arm, a soft gripper connector, a linkage assembly, a drive cylinder, a flange, and a drive power device for driving the drive cylinder. The flange is installed on the output end of the robotic arm. The drive cylinder and the drive power device are both installed on the flange. Multiple flexible arms are arranged in a circle along the axis of the drive cylinder to form a gripping space for gripping tomato fruits. The flexible arms are connected to the linkage assembly through the soft gripper connector. The linkage assembly is connected to the flange. The piston rod of the drive cylinder has a first position and a second position.

[0014] When the piston rod of the drive cylinder is in the first position, the flexible arm bends towards the inside of the clamping space under the drive of the power device, and multiple flexible arms form an enveloping clamp on the tomato fruit.

[0015] When the piston rod of the drive cylinder is in the second position, the flexible arm bends outward from the gripping space under the drive of the power device, thereby releasing the tomato fruit located in the gripping space.

[0016] Preferably, the identification and positioning system includes an FPV camera, a control board, a pitch brushless motor, a yaw brushless motor, and a base. The base is mounted on a moving mechanism and has an outer cover. The outer cover contains cavities for accommodating the FPV camera, control board, pitch brushless motor, and yaw brushless motor. The control board is mounted on the base, and the FPV camera is located above the control board. The FPV camera is mounted at the output end of the pitch brushless motor, and the housing of the pitch brushless motor is mounted at the output end of the yaw brushless motor. The housing of the yaw brushless motor is mounted on the base.

[0017] Preferably, a transport module for collecting tomato fruits is provided on one side of the mobile mechanism. The transport module includes an extended base plate, a transport box, wheel hubs and axles. The extended base plate is connected to the mobile mechanism, the transport box is installed on the extended base plate, and a pair of wheel hubs are arranged on the lower part of the extended base plate. The two wheel hubs are connected as one unit by axles.

[0018] Preferably, a powered roller conveyor mechanism for preliminary screening of tomato fruits is provided between the moving mechanism and the transport module. The powered roller conveyor mechanism includes a support frame, an adjusting rod structure, a roller conveyor, a protective structure, a drive motor, a combined chain, and a storage frame. The adjusting rod structure is located on the upper part of the extension base plate, and the support frame is located inside the adjusting rod structure. The roller conveyor is horizontally arranged on the top of the support frame, and the protective structure is located on the side of the roller conveyor. The protective structure has a discharge port located on the side close to the transport box. The housing of the drive motor is mounted on the support frame, and the output end of the drive motor is connected to the roller conveyor through the combined chain. The storage frame is located outside the adjusting rod structure and is used to collect unqualified tomato fruits after the preliminary screening by the roller conveyor.

[0019] Preferably, the moving mechanism includes a carrier platform, a control device, an omnidirectional wheel structure, and a battery that powers the omnidirectional wheel structure. The omnidirectional wheel structure includes a drive wheel and a power unit. The control device is mounted on the carrier platform. The omnidirectional wheel structure supports the carrier platform. The battery is located in the center of the carrier platform. The drive wheel is arranged in a rectangular pattern below the carrier platform. The power unit is mounted at the bottom of the carrier platform, and the output end of the power unit is connected to the drive wheel.

[0020] Preferably, the robotic arm includes a base cylinder, a support arm, a first support arm, a second support arm, and a third support arm. The base cylinder is mounted on a mechanical gripper. A first power device is disposed between the support arm and the base cylinder. The first power device is installed inside the base cylinder. The support arm is mounted on the output end of the first power device. The first support arm is hinged to the support arm. A second power device is disposed at the hinge point between the first support arm and the support arm. The second support arm is hinged to the first support arm. A third power device is disposed at the hinge point between the second support arm and the first support arm. A fourth power device is mounted on the second support arm. The third support arm is connected to the output end of the fourth power device. An end effector is connected to the third support arm.

[0021] Preferably, the soft gripper connector includes a silicone soft body and a connecting clip. The silicone soft body is fastened to the connecting clip and fixed to the connecting clip by screws. The screw mounting points are coated with sealant.

[0022] On the other hand, the present invention also proposes a tomato harvesting method using the above-mentioned tomato harvesting robot with a flexible end effector, comprising the following steps:

[0023] Guided into the picking area, the mobile mechanism moves within the tomato planting area under the guidance of the identification and positioning system, approaches the tomato plants, and enters the picking area. The identification and positioning system collects real-time image information of the tomato fruits, obtains the location information of the tomato fruits, and transmits the location information to the control device used to control the robotic arm.

[0024] The robotic arm is guided and positioned. The control device drives the power unit according to the position information to move the robotic arm to the picking position on the circular track, and drives the robotic arm to adjust to the appropriate picking posture so that the tomato fruit to be picked enters the picking space of the end effector.

[0025] The process involves gripping, picking, and releasing the tomato fruit. The piston rod of the control cylinder moves to the first position, and the flexible arms, driven by the power unit, bend inwards towards the gripping space. Multiple flexible arms envelop and grip the tomato fruit. Then, the robotic arm moves away from the tomato plant, separating the tomato fruit from the plant and harvesting it. The piston rod of the control cylinder then moves to the second position, and the flexible arms, driven by the power unit, bend outwards towards the gripping space, releasing the tomato fruit from the gripping space.

[0026] As a preferred embodiment, the above-mentioned harvesting method also includes designing the structural dimensions of the flexible arm according to the external dimensions of the tomato fruit;

[0027] S1. Tomato Structural Dimension Analysis

[0028] Using tomato fruits as the harvesting target, randomly select ripe tomato fruits, measure the transverse diameter Hd and longitudinal diameter Ld of the tomato fruits with vernier calipers, and then calculate the average value of the transverse diameter and longitudinal diameter and the average fruit shape ratio. The average fruit shape ratio is the ratio of the average longitudinal diameter to the average transverse diameter.

[0029] Sphericity represents how close an object's actual shape is to a sphere. Therefore, the geometric mean diameter d (mm) of a tomato is calculated using formula (1), and the sphericity (%) of the fruit is calculated using formula (2), thus representing the shape characteristics of the tomato fruit.

[0030] d = (L × H)¹ / ² (1)

[0031] Where d is the geometric mean diameter, mm; L is the average transverse diameter of the tomato, mm; and H is the average longitudinal diameter of the tomato, mm.

[0032]

[0033] Where Sρ is the sphericity, %; de is the diameter of the sphere with the same volume as the actual object, approximately 1 / 2. dc is the maximum diameter of the object, which is approximately the larger of the width and height, in mm;

[0034] Calculations show that the average sphericity of a tomato is about 91.305%, so the tomato fruit can be approximated as a sphere. Based on the above data, the design of the flexible arm in the end effector should be able to clamp a sphere of 50mm-100mm.

[0035] S2. Structural dimensions of the flexible arm in the end effector

[0036] For the flexible arm in the end effector to adapt to workpieces of a certain size range, it must meet three conditions: 1. The flexible arm in the end effector does not interfere with the tomato; 2. The flexible arm in the end effector cannot slip off when holding the largest tomato; 3. The flexible arm in the end effector cannot slip off when holding the smallest tomato.

[0037] 1. The flexible arm in the end effector does not interfere with the tomato fruit.

[0038] When the flexible arm holds the largest tomato, the support part of the flexible arm may interfere with the tomato. The condition to prevent interference is as follows:

[0039]

[0040] 2. Stably clamp the largest tomato fruit

[0041] The critical condition that must be met for the flexible arm in the end effector to stably grip the largest tomato is:

[0042]

[0043] 3. Stably clamp the smallest tomato fruit

[0044] The critical condition that must be met for the flexible arm in the end effector to stably grip the smallest tomato is:

[0045]

[0046] As a preferred option, the robotic arm drives the end effector to release the tomato fruits onto the powered roller conveyor mechanism, which performs preliminary screening of the tomato fruits.

[0047] Compared with existing technologies, the tomato harvesting robot and harvesting method provided by this invention have the following outstanding substantive features and significant progress:

[0048] 1. The tomato picking robot with a flexible end effector has an added ring conveyor mechanism on its moving mechanism. The ring track enables the robot arm to move in all directions on the horizontal plane. Under the action of the power unit, the mechanical gripper guides the robot arm to move vertically along the adjustment frame, which effectively expands the spatial coverage of the robot arm, widens the picking area of ​​the robot, and improves the practicality of the robot.

[0049] 2. The identification and positioning system of this tomato picking robot with a flexible end effector adopts an FPV system, which can continuously capture real-time information of tomatoes to be picked by using fully automatic, fixed-point, fixed-time, and fixed-height cruising and real-time data transmission functions. This helps to improve the accuracy of the identification and positioning system and reduce the damage rate of tomatoes during the picking process.

[0050] 3. This tomato-harvesting robot with a flexible end effector adds a flexible actuator to the output end of the robotic arm. Under the drive of the power unit, the flexible arm bends in the forward direction when the drive cylinder moves downward, enveloping and clamping the object. When the drive cylinder moves upward, the flexible arm bends in the reverse direction, releasing the clamped object. Furthermore, under the action of the force-shaping unit inside the flexible arm, the end effector can be optimized and adjusted accordingly for different clamped objects, thereby reducing the damage rate during the harvesting process, ensuring the success rate of a single harvest, expanding the versatility of the robotic arm for tomato harvesting, and providing a new opportunity for the development of traditional robotic arms.

[0051] 5. This tomato-picking robot with a flexible end effector adds a powered roller conveyor between the ring conveyor and the transport box. It utilizes the gap reserved in the roller conveyor to complete the initial screening of the picked tomatoes and transport the high-quality tomatoes to the transport box. This realizes the integration of tomato picking and sorting, saves working time, effectively improves the robot's working efficiency, and greatly reduces the intensity of manual labor. Attached Figure Description

[0052] Figure 1 This is a three-dimensional structural diagram of a tomato harvesting robot with a flexible end effector, according to an embodiment of the present invention.

[0053] Figure 2 yes Figure 1 A top view of a tomato-harvesting robot equipped with a flexible end effector.

[0054] Figure 3 yes Figure 1 Right view of a tomato-harvesting robot with a flexible end effector.

[0055] Figure 4 yes Figure 1 A bottom view of a tomato-harvesting robot equipped with a flexible end effector.

[0056] Figure 5 This is a three-dimensional structural diagram of the moving mechanism in an embodiment of the present invention.

[0057] Figure 6 yes Figure 5 A bottom view of China Mobile's headquarters.

[0058] Figure 7 This is a three-dimensional structural diagram of the annular conveying mechanism in an embodiment of the present invention.

[0059] Figure 8 yes Figure 7 Right view of the central ring conveyor mechanism.

[0060] Figure 9 yes Figure 7 Top view of the central ring conveyor mechanism.

[0061] Figure 10 This is a three-dimensional structural diagram of the identification and positioning system after removing the outer cover in an embodiment of the present invention.

[0062] Figure 11 This is a schematic diagram of the outer casing.

[0063] Figure 12 This is a schematic diagram of the assembly structure of the robot and the end effector in an embodiment of the present invention.

[0064] Figure 13 yes Figure 12A schematic diagram of the assembly structure of the robot and the end effector from another perspective.

[0065] Figure 14 yes Figure 13 A bottom view of the robot arm and end effector.

[0066] Figure 15 This is a schematic diagram of the assembly structure of the end effector in an embodiment of the present invention.

[0067] Figure 16 This is a schematic diagram of the flexible arm in an embodiment of the present invention.

[0068] Figure 17 This is a three-dimensional structural schematic diagram of the power roller conveyor mechanism in an embodiment of the present invention.

[0069] Figure 18 yes Figure 17 A top view of the medium-powered roller conveyor mechanism.

[0070] Figure 19 yes Figure 17 Right view of the central power roller conveyor mechanism.

[0071] Figure 20 This is a schematic diagram of the assembly structure of the combined chain in the power roller conveyor mechanism.

[0072] Figure 21 This is a flowchart illustrating the use of a tomato-picking robot with a flexible end effector, as described in an embodiment of the present invention.

[0073] Figure 22 This is a schematic diagram of the structure for measuring the external dimensions of a tomato fruit.

[0074] Figure 23 This is a simplified schematic diagram of the structure in the end effector where the flexible arm interferes with the tomato fruit.

[0075] Figure 24 This is a simplified diagram illustrating the critical state of the flexible arm in the end effector holding the largest tomato fruit.

[0076] Figure 25 This is a simplified diagram illustrating the critical state of the flexible arm in the end effector holding the smallest tomato fruit.

[0077] Reference numerals: 1. Moving mechanism; 2. Circular conveyor mechanism; 3. Identification and positioning system; 4. Robotic arm; 5. End effector; 6. Powered roller conveyor mechanism; 7. Transport module; 1-1. Carrier platform; 1-2. Control device; 1-3. Omnidirectional wheel structure; 1-4. Battery; 2-1. Support column; 2-2. Circular track; 2-3. Mechanical clamp; 2-4. Power unit; 2-5. Adjusting frame; 3-1. FPV camera; 3-2. Control board; 3-3. Pitch brushless motor; 3-4. Base; 3-5. Yaw brushless motor; 3-6. Outer cover; 4-1. Bottom cylinder; 4-2. Support arm; 4-3. First support arm; 4-4. Second support arm; 4-5. Third support arm; 4-6. First power unit; 4-7. Second power unit 4-8. Power unit; 4-9. Third power unit; 4-10. Fourth power unit; 4-11. First gear shaft; 4-12. Second gear shaft; 4-13. Chain; 5-1. Flexible arm; 5-2. Soft gripper connector; 5-3. Linkage assembly; 5-4. Drive cylinder; 5-5. Flange; 5-6. Drive power unit; 6-1. Support frame; 6-2. Adjusting rod structure; 6-3. Roller conveyor; 6-4. Protective structure; 6-5. Drive motor; 6-6. Combined chain; 6-7. Storage box; 7-1. Extended base plate; 7-2. Transport box; 7-3. Hub; 7-4. Shaft; 1-3-1. Drive wheel; 1-3-2. Main power unit; 5-1-1. Finger root; 5-1-2. Intermediate joint; 5-1-3. Finger tip. Detailed Implementation

[0078] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0079] like Figures 1-25 As shown in the figure, this invention proposes a tomato harvesting robot and harvesting method with a flexible end effector. The aim is to address the problems of fragile tomatoes, inconsistent fruit size, low harvesting efficiency and success rate of existing harvesting equipment, and, in particular, the inability of existing harvesting equipment to selectively harvest tomatoes. This invention provides a harvesting device to improve the poor versatility of existing harvesting robots, reduce damage to tomatoes during harvesting, and improve the quality of tomato harvesting.

[0080] This invention proposes a tomato harvesting robot with a flexible end effector. By adding a flexible actuator to the output end of the robotic arm, the flexible arm bends in the forward direction to envelop and grip the object when the drive cylinder moves downward, driven by a power unit. When the drive cylinder moves upward, the flexible arm bends in the reverse direction to release the gripped object. Furthermore, under the action of the force-shaping unit inside the flexible arm, the end effector can be optimized and adjusted accordingly for different gripped objects. This reduces the damage rate during the harvesting process, ensures the success rate of a single harvest, improves the poor versatility of existing harvesting robots, reduces damage to tomato fruits during harvesting, and enhances the quality of tomato harvesting.

[0081] Tomato-harvesting robot with a flexible end effector

[0082] like Figures 1-3 As shown, a tomato harvesting robot with a flexible end effector includes a mobile mechanism 1, a recognition and positioning system 3, and a robotic arm 4. The mobile mechanism 1 is used to move within the tomato planting area. The recognition and positioning system 3 is mounted on the mobile mechanism 1. The recognition and positioning system 3 is used to collect real-time image information of the tomato fruits and guide the movement of the mobile mechanism 1 within the tomato planting area. The robotic arm 4 is used to grip and harvest the tomato fruits.

[0083] like Figure 1 As shown, a ring conveying mechanism 2 is provided between the robot arm 4 and the moving mechanism 1. The fixed end of the robot arm 4 is connected to the moving mechanism 1 through the ring conveying mechanism 2.

[0084] like Figures 7-9 As shown, the annular conveying mechanism 2 includes a support column 2-1, an annular track 2-2, a mechanical clamp 2-3, a power unit 2-4, and an adjusting frame 2-5. The annular track 2-2 is mounted above the moving mechanism 1 via the support column 2-1. The adjusting frame 2-5 is mounted on the annular track 2-2 and slides around it. The power unit 2-4 is mounted on the adjusting frame 2-5. The mechanical clamp 2-3 is connected to the output end of the power unit 2-4. The power unit 2-4 drives the mechanical clamp 2-3 to move along a sliding plane perpendicular to the annular track 2-2. The fixed end of the robot arm 4 is mounted on the mechanical clamp 2-3.

[0085] For example, the support column 2-1 adopts an inner sleeve structure. This design allows for continuous adjustment of the working height of the annular conveyor mechanism 2 according to actual height requirements, thereby improving work efficiency. The annular track 2-2 should ensure the smoothness of its surface to better control the smoothness of the robot arm 4's movement.

[0086] like Figure 8As shown, adjustment frames 2-5 should have sufficient vertical space for movement. This setting allows for better adaptation to the uncertain height of tomatoes harvested in different environments, thereby ensuring a higher harvesting success rate.

[0087] like Figure 12 Combination Figure 15 and Figure 16 As shown, the output end of the robotic arm 4 is equipped with an end effector 5 for gripping tomato fruits. The end effector 5 includes a flexible arm 5-1, a soft gripper connector 5-2, a linkage assembly 5-3, a drive cylinder 5-4, a flange 5-5, and a drive power unit 5-6 for driving the drive cylinder 5-4. The flexible arm further includes finger roots 5-1-1, intermediate joints 5-1-2, and fingertips 5-1-3.

[0088] like Figure 15 As shown, flange 5-5 is mounted on the output end of robotic arm 4. Drive cylinder 5-4 and drive power unit 5-6 are both mounted on flange 5-5. Multiple flexible arms 5-1 are arranged in a circle along the axis of drive cylinder 5-4, forming a gripping space for holding tomato fruits. Flexible arms 5-1 are connected to connecting rod assembly 5-3 via soft gripper connector 5-2. Connecting rod assembly 5-3 is connected to flange 5-5, and the piston rod of drive cylinder 5-4 has a first position and a second position.

[0089] For example, the soft gripper connector 5-2 includes a silicone soft body and a connecting clip. The silicone soft body is snapped onto the connecting clip. The silicone soft body is secured to the connecting clip by screws. Sealant is applied to the screw mounting points.

[0090] like Figure 5 As shown, when the piston rod of the drive cylinder 5-4 is in the first position, the flexible arm 5-1 bends towards the inside of the clamping space under the drive of the power device 5-6, and multiple flexible arms 5-1 form an enveloping clamp on the tomato fruit.

[0091] When the piston rod of the drive cylinder 5-4 is in the second position, the flexible arm 5-1, driven by the drive power device 5-6, bends outward toward the gripping space, thereby releasing the tomato fruit located in the gripping space.

[0092] The flexible arm 5-1 is designed as a sheet-like support structure. This design allows the drive cylinder 5-4 to bend in the forward direction when moving downwards, enveloping and clamping the object, and to bend in the reverse direction when moving upwards, releasing the clamped object.

[0093] To further reduce damage during tomato harvesting, a force-shaping unit is designed on the inner side of the flexible arm 5-1. This design allows the end effector 5 to be adjusted for different objects being gripped. For symmetrical objects, all three flexible arms 5-1 conform to the object's shape and provide a conformal embrace. For asymmetrical objects, only some of the flexible arms 5-1 are engaged, utilizing the shaping bag to fix and grip the object. Furthermore, for sharp objects, the shaping bag conforms to the sharp edges.

[0094] [Mobile Agency]

[0095] like Figures 4-6 As shown, the moving mechanism 1 includes a carrier platform 1-1, a control device 1-2, an omnidirectional wheel structure 1-3, and a battery 1-4 that powers the omnidirectional wheel structure 1-3. The omnidirectional wheel structure 1-3 includes a drive wheel 1-3-1 and a power unit 1-3-2. The control device 1-2 is mounted on the carrier platform 1-1. The omnidirectional wheel structure 1-3 supports the carrier platform 1-1. The battery 1-4 is located in the center of the carrier platform 1-1. The drive wheels 1-3-1 are arranged in a rectangular pattern below the carrier platform 1-1. The power unit 1-3-2 is mounted on the bottom of the carrier platform 1-1. The output end of the power unit 1-3-2 is connected to the drive wheels 1-3-1.

[0096] The carrier platform 1-1 can be made of acrylic sheet. This design is based on the fact that this specially treated acrylic glass has high hardness, good anti-aging properties, can withstand outdoor environments such as wind, rain, and sunlight, and has good transparency, which facilitates operation for personnel during maintenance.

[0097] For example, control devices 1-2 use a PLC controller. This configuration leverages the advantages of high reliability, strong anti-interference capability, wide applicability, low construction workload, and low energy consumption to control the movement direction, running speed, and number of steps of the stepper motor through the high-speed output signal of the PLC, while simultaneously controlling the servo motor through the pulses sent by the control.

[0098] The omnidirectional wheel structure 1-3 in the mobile mechanism 1 is driven by a four-pronged power unit 1-3-2. This configuration ensures sufficient power for the robot during movement, overcoming the limitations imposed by harsh environments on the robot's power requirements. The power unit 1-3-2 uses a stepper motor, specifically a type 42 stepper motor with a step angle of 1.8°. With a direct pulse signal, each pulse can control the motor shaft to rotate 1.8°, and 200 pulses can complete a circular motion of the motor shaft.

[0099] [Identification and Positioning System]

[0100] like Figure 10As shown, the identification and positioning system 3 includes an FPV camera 3-1, a control board 3-2, a pitch brushless motor 3-3, a yaw brushless motor 3-5, and a base 3-4. The base 3-4 is mounted on the moving mechanism 1. Combined with... Figure 11 As shown, an outer cover 3-6 is mounted on the base 3-4. The outer cover 3-6 contains cavities for accommodating the FPV camera 3-1, control board 3-2, brushless pitch motor 3-3, and brushless yaw motor 3-5. The control board 3-2 is mounted on the base 3-4. The FPV camera 3-1 is located above the control board 3-2. The FPV camera 3-1 is mounted at the output end of the brushless pitch motor 3-3. The housing of the brushless pitch motor 3-3 is mounted at the output end of the brushless yaw motor 3-5. The housing of the brushless yaw motor 3-5 is mounted on the base 3-4.

[0101] The FPV camera 3-1 uses an FPV system. This setup allows for continuous capture of real-time information about the tomatoes to be harvested, utilizing fully automatic, fixed-point, fixed-time, and fixed-altitude cruise capabilities, as well as real-time data transmission. This helps improve the accuracy of the identification and positioning system and reduce the damage rate of tomatoes during the harvesting process.

[0102] [Robotic arm]

[0103] like Figures 12-14 As shown, the robotic arm 4 includes a base cylinder 4-1, a support arm 4-2, a first support arm 4-3, a second support arm 4-4, and a third support arm 4-5. The base cylinder 4-1 is mounted on a mechanical clamp 2-3. A first power unit 4-6 is disposed between the support arm 4-2 and the base cylinder 4-1, and the first power unit 4-6 is installed inside the base cylinder 4-1. The support arm 4-2 is mounted on the output end of the first power unit 4-6. The first support arm 4-3 is hinged to the support arm 4-2. A second power unit 4-7 is disposed at the hinge point between the first support arm 4-3 and the support arm 4-2. The second support arm 4-4 is hinged to the first support arm 4-3. A third power unit 4-8 is disposed at the hinge point between the second support arm 4-4 and the first support arm 4-3. A fourth power unit 4-9 is mounted on the second support arm 4-4. The third support arm 4-5 is connected to the output end of the fourth power unit 4-9. An end effector 5 is connected to the third support arm 4-5.

[0104] like Figure 12 As shown, a first gear shaft 4-10 is provided in the middle of the third arm 4-5, and a second gear shaft 4-11 is provided at the second end of the third arm 4-5, connecting the third arm 4-5 and the end effector 5 into one unit. A chain 4-12 is provided on the side of the third arm 4-5, connecting the first gear shaft 4-10 and the second gear shaft 4-11 into one unit.

[0105] For example, the first power unit 4-6, the second power unit 4-7, the third power unit 4-8, and the fourth power unit 4-9 all use servo motors. The bottom cylinder 4-1 is cylindrical, and its dimensions should perfectly match the opening of the mechanical clamp 2-3 and the width of the circular track 2-2. This design allows for better utilization of the modular characteristics of the robot's components, ensuring efficient assembly and effectively reducing later maintenance costs through modular maintenance.

[0106] [Transportation module and powered roller conveyor mechanism]

[0107] like Figure 1 As shown, a transport module 7 for collecting tomato fruits is provided on one side of the moving mechanism 1. The transport module 7 includes an extended base plate 7-1, a transport box 7-2, wheel hubs 7-3 and wheel axles 7-4. The extended base plate 7-1 is connected to the moving mechanism 1. The transport box 7-2 is installed on the extended base plate 7-1. A pair of wheel hubs 7-3 are arranged on the lower part of the extended base plate 7-1. The two wheel hubs 7-3 are connected as one unit through the wheel axle 7-4.

[0108] like Figures 17-20 As shown, a powered roller conveyor mechanism 6 for preliminary screening of tomato fruits is provided between the moving mechanism 1 and the transport module 7. The powered roller conveyor mechanism 6 includes a support frame 6-1, an adjusting rod structure 6-2, a roller conveyor 6-3, a protective structure 6-4, a drive motor 6-5, a combined chain 6-6, and a storage box 6-7. The adjusting rod structure 6-2 is located on the upper part of the extended base plate 7-1. The support frame 6-1 is located inside the adjusting rod structure 6-2. The roller conveyor is horizontally positioned on top of the support frame 6-1. The protective structure 6-4 is located on the side of the roller conveyor. A discharge port is provided on the protective structure 6-4. The discharge port is located on the side near the transport box 7-2. The housing of the drive motor 6-5 is mounted on the support frame 6-1. The output end of the drive motor 6-5 is connected to the roller conveyor via the combined chain 6-6. The storage box 6-7 is located outside the adjusting rod structure 6-2 and is used to collect tomato fruits that fail the preliminary screening by the roller conveyor.

[0109] like Figure 17 As shown, the adjustable height of the adjusting rod structure 6-2 should not be less than the adjustable height of the inner sleeve structure used in the support column 2-1. This arrangement ensures that the annular conveyor mechanism 2, the powered roller conveyor mechanism 6, and the transport box 7-2 can be matched with each other, improving the coordination between the components and thus ensuring the high efficiency of the robot's operation.

[0110] For example, the roller gap should be adjusted according to the actual tomato harvesting. This setting enhances the environmental adaptability of the powered roller conveyor mechanism 6, improves the robot's versatility, and thus enhances the robot's market competitiveness.

[0111] like Figure 17As shown, the protective range of the protective structure 6-4 should be designed based on the maximum protective height of the tomatoes being harvested. This design ensures that the tomatoes harvested by the robotic arm 4 will not leak or fall to the side during the process of being transported to the transport box 7-2 via the powered roller conveyor mechanism 6, further guaranteeing the "safety" of the fruit.

[0112] [Harvesting Method]

[0113] When using the tomato harvesting robot with a flexible end effector proposed in this embodiment of the invention, such as... Figure 21 As shown, it includes the following steps:

[0114] Guided into the picking area, the mobile mechanism moves within the tomato planting area under the guidance of the identification and positioning system, approaches the tomato plants, and enters the picking area. The identification and positioning system collects real-time image information of the tomato fruits, obtains the location information of the tomato fruits, and transmits the location information to the control device used to control the robotic arm.

[0115] The robotic arm is guided and positioned. The control device drives the power unit according to the position information to move the robotic arm to the picking position on the circular track, and drives the robotic arm to adjust to the appropriate picking posture so that the tomato fruit to be picked enters the picking space of the end effector.

[0116] The process involves gripping, picking, and releasing the tomato fruit. The piston rod of the control cylinder moves to the first position, and the flexible arms, driven by the power unit, bend inwards towards the gripping space. Multiple flexible arms envelop and grip the tomato fruit. Then, the robotic arm moves away from the tomato plant, separating the tomato fruit from the plant and harvesting it. The piston rod of the control cylinder then moves to the second position, and the flexible arms, driven by the power unit, bend outwards towards the gripping space, releasing the tomato fruit from the gripping space.

[0117] For example, a tomato-harvesting robot equipped with a flexible end effector includes the following specific steps when actually harvesting tomato fruits:

[0118] Step 1: Unlike general industrial robots, harvesting robots operate in complex environments and need to detect and judge target fruits in real time during movement, harvesting fruits according to requirements. To reach the target location as efficiently and reliably as possible, the robot should be able to determine its own path based on an environmental model and the target location. During operation, the robot first moves to a distance of 3-5 meters from the plant. Using the recognition and positioning system 3, it detects the leaves and tomatoes that need to be removed, obtaining the tomato's location information. This information is then fed back to the control device 1-2, which controls the omnidirectional wheel structure 1-3 to move forward continuously. If the omnidirectional wheel structure 1-3 reaches the optimal position but still cannot meet the harvesting requirements, the information is further transmitted to the first power unit 4-6, the second power unit 4-7, the third power unit 4-8, the fourth power unit 4-9, and the power unit 2-4. The circular track 2-2 enables the robotic arm 4 to move omnidirectionally in the horizontal plane. Under the action of the power unit 2-4, the mechanical gripper 2-3 guides the robotic arm 4 to move vertically along the adjustment frame 2-5, continuously adjusting the robotic arm 4's orientation to find the optimal harvesting point. Once the recognition and positioning system 3 identifies that the optimal harvesting point has been reached, it sends information to the fifth power unit 5-6. 6. Driven by the fifth power unit 5-6, when the drive cylinder structure 5-4 moves downward, the flexible arm 5-1 bends in the forward direction to envelop and clamp the object. When the drive cylinder structure 5-4 moves upward, the flexible arm 5-1 bends in the reverse direction to release the clamped object. Under the action of the force shaping unit inside the flexible arm 5-1, the end effector 5 can make corresponding optimization adjustments for different clamped objects. When a whole tomato is picked, the first power unit 4-6, the second power unit 4-7, the third power unit 4-8, the fourth power unit 4-9 and the power unit 2-4 will continue to clamp the tomato onto the roller 6-3 of the power roller conveyor mechanism 6 under the signal of the control device 1-2, and gently release the flexible arm 5-1 so that it falls. The drive motor 6-5 and the combined chain 6-6 drive the roller 6-3 to rotate continuously, thereby completing the task of transferring the tomato to the transport box 7-2 and the initial screening of the tomato. At this point, a complete picking process is completed.

[0119] Step 2, the working method of the picking robot identification and positioning system 3: First, acquire digital images of tomatoes, and then use image processing algorithms to identify and determine the position of tomatoes in the image. Due to the complexity of the environment, sometimes it is necessary to use multi-sensor multi-information fusion technology to enhance the perception and recognition capabilities of the environment and to use the shape of fruits to identify and locate the fruits.

[0120] Step 3: The plants growing the fruit are fixed yet randomly distributed in space. Therefore, when harvesting the fruit, the robot needs to actively approach and accurately locate the target, which requires the robot to have a movement mechanism 1. During the operation of the movement mechanism 1, the advantages of the omnidirectional wheel structure 1-3, which can achieve translation in any direction and perform any complex arc motion, are fully utilized. Under the premise that the battery 1-4 driving the omnidirectional wheel structure 1-3 is continuously powered, the robot can continuously start, stop, and rotate according to the instructions sent by the control device 1-2.

[0121] Step 4: The robotic arm 4, also known as the manipulator, is a mechanical device with similar motion functions to a human arm, enabling the work object to move within space. It is the entity upon which the robot relies to complete its work tasks. In the harvesting robot, the main task of the robotic arm 4 is to move the end effector 5 to the location of the target fruit that can be picked. Its workspace requires the robot to be able to reach any target fruit. In the specific working process, the first power unit 4-6 provides power to the support arm 4-2, realizing the horizontal rotation of the robotic arm 4. The second power unit 4-7, the third power unit 4-8, and the fourth power unit 4-9 control the first arm 4-3, the second arm 4-4, and the third arm 4-5 to change and adjust their angles. Through the coordinated operation of the first gear shaft 4-10, the second gear shaft 4-11, and the chain 4-12, the end effector is continuously moved to a suitable picking position in space.

[0122] Step 5: The flexible gripper has strong adaptability, enabling non-destructive gripping and stable handling of objects of varying shapes and sizes. During operation, to ensure the shaping film adheres well to the object being gripped and to minimize the impact of the shaping unit on the bending performance of the flexible arm 5-1, a soft silicone rubber material is used to create the shaping film. This soft silicone film contacts the harvested tomato and fits its three-dimensional contour. The solenoid valve activates the vacuum source, causing the film to solidify and constrain the object.

[0123] To further reduce damage to tomato fruits during harvesting, the harvesting method also includes designing the structural dimensions of the flexible arm based on the shape and size of the tomato fruit. The specific analysis process is as follows:

[0124] S1. Tomato Structural Dimension Analysis

[0125] Tomatoes are used as the harvesting target, and their geometric dimensions need to be measured to provide a reference for the design dimensions of the flexible arm in the end effector. This invention uses "Pink 734" tomatoes as the harvesting target, randomly selecting tomatoes at their ripening stage, such as... Figure 22 As shown, the transverse diameter Hd and longitudinal diameter Ld of tomatoes were measured using vernier calipers, and their mean and fruit shape ratio were calculated. The measurement methods and statistical results of the geometric dimensions of tomatoes were recorded (as shown in Table 1).

[0126] Table 1 Geometric parameters of tomatoes

[0127]

[0128] Sphericity represents how close an object's actual shape is to a sphere. Therefore, the geometric mean diameter d (mm) of a tomato is calculated using formula (1), and the sphericity (%) of the fruit is calculated using formula (2), thus representing the shape characteristics of the tomato fruit.

[0129] d = (L × H)¹ / ² (1)

[0130] Where d is the geometric mean diameter, mm; L is the average transverse diameter of the tomato, mm; and H is the average longitudinal diameter of the tomato, mm.

[0131]

[0132] Where Sρ is the sphericity, %; de is the diameter of the sphere with the same volume as the actual object, approximately 1 / 2. dc is the maximum diameter of the object, approximately the larger of the width and height, in mm.

[0133] Calculations show that the average sphericity of a tomato is about 91.305%, so a tomato can be approximated as a sphere. Based on this data, the design of the flexible arm in the end effector should be able to clamp a sphere of 50-100mm.

[0134] S2. Structural dimensions of the flexible arm in the end effector

[0135] like Figures 23-25 As shown, for the flexible arm in the end effector to adapt to workpieces of a certain size range, it should meet three conditions: 1. The flexible arm in the end effector does not interfere with the tomato; 2. The flexible arm in the end effector can hold the largest tomato without slipping; 3. The flexible arm in the end effector can hold the smallest tomato without slipping.

[0136] 1. The flexible arm in the end effector does not interfere with the tomato fruit.

[0137] When the flexible arm holds the largest tomato, the support part of the flexible arm may interfere with the tomato. The condition to prevent interference is as follows:

[0138]

[0139] Wherein, L1 is the flexible arm finger root support part, mm; θ is the angle formed between the center of the drive cylinder and the center and side wall of the tomato fruit, °; β is the angle formed between the flexible arm finger root support part and the center of the tomato fruit, °; α is the distance from the flexible arm finger root to the transverse diameter of the tomato fruit, mm; Rmax is the maximum radius of the tomato fruit, mm.

[0140] 2. Stably clamp the largest tomato fruit

[0141] The critical condition that must be met for the flexible arm in the end effector to stably grip the largest tomato is:

[0142]

[0143] Where α is the distance between the flexible gripper connector and the center line of the flange, mm; L1 is the total length of the flexible arm finger root and intermediate joint, mm; θ is the angle formed between the flexible arm fingertip and the center of the tomato fruit, mm; β is the angle formed between the finger root and intermediate joint and the center of the tomato fruit, mm; b is the length of the flexible arm fingertip, mm; and Rmax is the maximum radius of the tomato fruit, mm.

[0144] 3. Stably clamp the smallest tomato fruit

[0145] The critical condition that must be met for the flexible arm in the end effector to stably grip the smallest tomato is:

[0146]

[0147] Where α is the distance between the flexible gripper connector and the center line of the flange, mm; L1 is the total length of the flexible arm finger root and intermediate joint, mm; θ is the angle formed between the flexible arm fingertip and the center of the tomato fruit, mm; β is the angle formed between the finger root and intermediate joint and the center of the tomato fruit, mm; b is the length of the flexible arm fingertip, mm; and Rmin is the minimum radius of the tomato fruit, mm.

[0148] This invention presents a tomato-harvesting robot with a flexible end effector. Four omnidirectional wheels work together to achieve translation in any direction and perform complex arc movements. A fully automatic, timed, and height-controlled navigation system is used for identification and positioning, transmitting captured data in real-time to a control device. This drives the robotic arm to continuously adjust its spatial orientation and fully utilizes the advantages of the flexible end effector. Driven by a fifth power unit, the flexible arm bends in the forward direction when the drive cylinder moves downward, enveloping and gripping the object. When the drive cylinder moves upward, the flexible arm bends in the reverse direction, releasing the gripped object. Furthermore, the robot utilizes the pre-reserved gaps in the roller conveyor to complete the initial screening of the harvested tomatoes, transporting high-quality tomatoes to the transport box. This integrates tomato harvesting and sorting, saving working time, effectively improving the robot's efficiency, significantly reducing manual labor intensity, expanding the robot's applicability, and enhancing its environmental adaptability. It also solves the problem of traditional tomato-harvesting robots being theoretically limited in their versatility and having high manufacturing costs.

[0149] This invention is not limited to the specific technical solutions described in the above embodiments. Besides the above embodiments, this invention may have other implementation methods. For those skilled in the art, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A tomato harvesting robot with a flexible end effector, comprising a moving mechanism, a recognition and positioning system, and a robotic arm, wherein the moving mechanism is used to move within a tomato planting area, the recognition and positioning system is mounted on the moving mechanism, the recognition and positioning system is used to collect real-time image information of tomato fruits and guide the moving mechanism's movement within the tomato planting area, and the robotic arm is used to grip and harvest the tomato fruits, characterized in that: A ring conveying mechanism is provided between the robotic arm and the moving mechanism, and the fixed end of the robotic arm is connected to the moving mechanism through the ring conveying mechanism; The annular conveying mechanism includes a support column, an annular track, a mechanical clamp, a power unit, and an adjusting frame. The annular track is mounted above the moving mechanism via the support column. The adjusting frame is mounted on the annular track and slides around the annular track. The power unit is mounted on the adjusting frame. The mechanical clamp is connected to the output end of the power unit. The power unit is used to drive the mechanical clamp to move along a sliding plane perpendicular to the annular track. The fixed end of the manipulator is mounted on the mechanical clamp. The output end of the robotic arm is equipped with an end effector for gripping tomato fruits. The end effector includes a flexible arm, a soft gripper connector, a linkage assembly, a drive cylinder, a flange, and a drive power device for driving the drive cylinder. The flange is installed on the output end of the robotic arm. The drive cylinder and the drive power device are both installed on the flange. Multiple flexible arms are arranged in a circle along the axis of the drive cylinder to form a gripping space for gripping tomato fruits. The flexible arms are connected to the linkage assembly through the soft gripper connector. The linkage assembly is connected to the flange. The piston rod of the drive cylinder has a first position and a second position. When the piston rod of the drive cylinder is in the first position, the flexible arm bends towards the inside of the clamping space under the drive of the power device, and multiple flexible arms form an enveloping clamp on the tomato fruit. When the piston rod of the drive cylinder is in the second position, the flexible arm bends outward from the gripping space under the drive of the power device, thereby releasing the tomato fruit located in the gripping space. The mobile mechanism is provided with a transport module for collecting tomato fruits on one side. The transport module includes an extended base plate, a transport box, wheel hubs and axles. The extended base plate is connected to the mobile mechanism. The transport box is installed on the extended base plate. A pair of wheel hubs are arranged on the lower part of the extended base plate. The two wheel hubs are connected as one unit by axles. A powered roller conveyor mechanism for preliminary screening of tomato fruits is provided between the moving mechanism and the transport module. The powered roller conveyor mechanism includes a support frame, an adjusting rod structure, a roller conveyor, a protective structure, a drive motor, a combined chain, and a storage frame. The adjusting rod structure is located on the upper part of the extension base plate, and the support frame is located inside the adjusting rod structure. The roller conveyor is horizontally arranged on the top of the support frame. The protective structure is located on the side of the roller conveyor and has a discharge port located on the side near the transport box. The housing of the drive motor is mounted on the support frame, and the output end of the drive motor is connected to the roller conveyor via the combined chain. The storage frame is located outside the adjusting rod structure and is used to collect tomato fruits that fail the preliminary screening by the roller conveyor.

2. The tomato harvesting robot with a flexible end effector according to claim 1, characterized in that, The identification and positioning system includes an FPV camera, a control board, a pitch brushless motor, a yaw brushless motor, and a base. The base is mounted on a moving mechanism and has an outer cover. The outer cover contains cavities for accommodating the FPV camera, control board, pitch brushless motor, and yaw brushless motor. The control board is mounted on the base, and the FPV camera is located above the control board. The FPV camera is mounted at the output end of the pitch brushless motor, and the housing of the pitch brushless motor is mounted at the output end of the yaw brushless motor. The housing of the yaw brushless motor is mounted on the base.

3. The tomato harvesting robot with a flexible end effector according to claim 1, characterized in that, The moving mechanism includes a carrier platform, a control device, an omnidirectional wheel structure, and a battery that powers the omnidirectional wheel structure. The omnidirectional wheel structure includes a drive wheel and a power unit. The control device is mounted on the carrier platform. The omnidirectional wheel structure supports the carrier platform. The battery is located in the center of the carrier platform. The drive wheels are arranged in a rectangular pattern below the carrier platform. The power unit is mounted at the bottom of the carrier platform, and its output end is connected to the drive wheels.

4. The tomato harvesting robot with a flexible end effector according to claim 1, characterized in that, The robotic arm includes a base cylinder, a support arm, a first support arm, a second support arm, and a third support arm. The base cylinder is mounted on a mechanical gripper. A first power device is disposed between the support arm and the base cylinder. The first power device is installed inside the base cylinder. The support arm is mounted on the output end of the first power device. The first support arm is hinged to the support arm. A second power device is disposed at the hinge point between the first support arm and the support arm. The second support arm is hinged to the first support arm. A third power device is disposed at the hinge point between the second support arm and the first support arm. A fourth power device is mounted on the second support arm. The third support arm is connected to the output end of the fourth power device. The end effector is connected to the third support arm.

5. The tomato harvesting robot with a flexible end effector according to claim 1, characterized in that, The soft gripper connector includes a silicone soft body and a connecting clip. The silicone soft body is fastened to the connecting clip and fixed to the connecting clip by screws. The screw mounting points are coated with sealant.

6. The tomato harvesting method of the tomato harvesting robot with a flexible end effector according to any one of claims 1-5, characterized in that, include: Guided into the picking area, the mobile mechanism moves within the tomato planting area under the guidance of the identification and positioning system, approaches the tomato plants, and enters the picking area. The identification and positioning system collects real-time image information of the tomato fruits, obtains the location information of the tomato fruits, and transmits the location information to the control device used to control the robotic arm. The robotic arm is guided and positioned. The control device drives the power unit according to the position information to move the robotic arm to the picking position on the circular track, and drives the robotic arm to adjust to the appropriate picking posture so that the tomato fruit to be picked enters the picking space of the end effector. The process involves gripping, picking, and releasing the tomato fruit. The piston rod of the control cylinder moves to the first position, and the flexible arms, driven by the power unit, bend inwards towards the gripping space. Multiple flexible arms envelop and grip the tomato fruit. Then, the robotic arm moves away from the tomato plant, separating the tomato fruit from the plant and harvesting it. The piston rod of the control cylinder then moves to the second position, and the flexible arms, driven by the power unit, bend outwards towards the gripping space, releasing the tomato fruit from the gripping space.

7. The tomato harvesting method of the tomato harvesting robot with a flexible end effector according to claim 6, characterized in that, This includes designing the structural dimensions of the flexible arm based on the shape and size of the tomato fruit; S1. Tomato Structural Dimension Analysis Using tomato fruits as the harvesting target, randomly select ripe tomato fruits, measure the transverse diameter Hd and longitudinal diameter Ld of the tomato fruits with vernier calipers, and then calculate the average value of the transverse diameter and longitudinal diameter and the average fruit shape ratio. The average fruit shape ratio is the ratio of the average longitudinal diameter to the average transverse diameter. Sphericity represents how close an object's actual shape is to a sphere. Therefore, the geometric mean diameter d (mm) of a tomato is calculated using formula (1), and the sphericity (%) of the fruit is calculated using formula (2), thus representing the shape characteristics of the tomato fruit. （1） Where d is the geometric mean diameter, mm; L is the average transverse diameter of the tomato, mm; and H is the average longitudinal diameter of the tomato, mm. （2） in, % for sphericity; The diameter of the sphere is approximately equal to the volume of the actual object. mm; The maximum diameter of the object is approximately the larger of its width and height, expressed in mm. Calculations show that the average sphericity of a tomato is about 91.305%, so the tomato fruit can be approximated as a sphere. Based on the above data, the design of the flexible arm in the end effector should be able to clamp a sphere of 50mm-100mm. S2. Structural dimensions of the flexible arm in the end effector For the flexible arm in the end effector to adapt to workpieces of a certain size range, it must meet three conditions:

1. The flexible arm in the end effector does not interfere with the tomato; 2. The flexible arm in the end effector cannot slip off when holding the largest tomato; 3. The flexible arm in the end effector cannot slip off when holding the smallest tomato.

1. The flexible arm in the end effector does not interfere with the tomato fruit. When the flexible arm holds the largest tomato, the support part of the flexible arm may interfere with the tomato. The condition to prevent interference is as follows: （3） in, For the flexible arm finger root support section, mm; The angle between the center of the driving cylinder and the center and side wall of the tomato fruit is °; The flexible arm's finger root support portion forms an angle of ° with the center of the tomato fruit; The distance from the base of the flexible arm finger to the transverse diameter of the tomato fruit, in mm; The radius of the tomato fruit is [value] mm.

2. Stably clamp the largest tomato fruit The critical condition that must be met for the flexible arm in the end effector to stably grip the largest tomato is: （4） in, The distance between the soft gripper connector and the centerline of the flange, in mm; The total length of the flexible arm finger root and intermediate joint, in mm; The angle formed between the flexible arm fingertip and the center of the tomato fruit is mm; The angle formed between the base of the finger and the middle joint and the center of the tomato fruit is mm; The length of the flexible arm fingertip, in mm; The radius of the tomato fruit is [value] mm.

3. Stably clamp the smallest tomato fruit The critical condition that must be met for the flexible arm in the end effector to stably grip the smallest tomato is: （5） in, The distance between the soft gripper connector and the centerline of the flange, in mm; The total length of the flexible arm finger root and intermediate joint, in mm; The angle formed between the flexible arm fingertip and the center of the tomato fruit is mm; The angle formed between the base of the finger and the middle joint and the center of the tomato fruit is mm; The length of the flexible arm fingertip, in mm; Let be the minimum radius of the tomato fruit, in mm.

8. The tomato harvesting method of the tomato harvesting robot with a flexible end effector according to claim 6, characterized in that, The robotic arm drives the end effector to release the tomato fruits onto the powered roller conveyor mechanism, which performs preliminary screening of the tomato fruits.

Images