A picking robot end effector

Abstract

The application discloses a picking robot end effector, which comprises a flexible mechanical finger, a clamping mechanism, a branch folding mechanism and a rotating mechanism, the rotating mechanism is used for connecting the picking robot, the branch folding mechanism is rotatably connected to the rotating mechanism, the clamping mechanism is arranged on the branch folding mechanism, the flexible mechanical finger is connected to the clamping mechanism, the clamping mechanism can make the flexible mechanical finger open or clamp, and the flexible mechanical finger is used for picking fruits. The picking action is integrated on the end effector of the picking robot, compared with a traditional six-axis mechanical arm, the picking robot end effector greatly reduces the control difficulty of the mechanical arm, reduces the design difficulty of the picking robot, is more suitable for picking fruits in a shed frame pear orchard, makes the end effector realize the clamping and picking actions, the mechanism is simple and low in cost, is convenient to control, and improves the picking efficiency.

Description

Technical Field

[0001] This invention relates to the technical field of harvesting machines, and in particular to an end effector for a harvesting robot. Background Technology

[0002] Harvesting robots are highly collaborative systems that integrate artificial intelligence, electromechanical control, machine vision, multi-sensor fusion, and other multidisciplinary technologies to autonomously complete tasks such as identifying, locating, picking, and collecting target fresh fruits. In recent years, with the increasing maturity of related technologies and hardware, the application of harvesting robots in fresh fruits such as citrus, apples, kiwis, and strawberries has been widely studied and has shown promising commercial application prospects. Fruit picking by harvesting robots refers to the process of separating the fruit stem from the branch using an end effector and a robotic arm; this is a crucial part of the harvesting task. Existing fruit picking methods for harvesting robots mainly fall into two categories: pruning and biomimetic picking.

[0003] my country is a major pear producer, with a total pear cultivation area of ​​943,400 hectares and a total output of 16.078 million tons, accounting for over 60% of the world's total pear cultivation area and output. Harvesting is a crucial part of pear production, but it has long relied on manual labor, resulting in a large and concentrated demand for labor, which has become one of the biggest constraints on the industry's development. Currently, research on harvesting robots for fresh pears is still lacking. Due to the differences in morphological and physiological factors such as the diameter, length, growth angle, and separation force between the fruit stalk and branch of different crops, it is difficult to directly use the end effector solutions of other existing harvesting robots. Furthermore, trellis-grown pears generally grow at a uniform height, and their fruit axis is essentially vertically downward. To improve harvesting efficiency and simplify the development of pear-harvesting robots, there is an urgent need to design an end effector that integrates harvesting actions. Summary of the Invention

[0004] The purpose of this invention is to provide an end effector for a harvesting robot to solve the problems existing in the prior art, enabling the actuator to perform clamping and harvesting actions. The mechanism is simple and low-cost, easy to operate, and improves harvesting efficiency.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides an end effector for a harvesting robot, comprising a flexible mechanical finger, a clamping mechanism, a branch-breaking mechanism, and a rotating mechanism. The rotating mechanism is used to connect to the harvesting robot, and the branch-breaking mechanism is rotatably connected to the rotating mechanism. The clamping mechanism is provided on the branch-breaking mechanism, and the flexible mechanical finger is connected to the clamping mechanism. The clamping mechanism can open or close the flexible mechanical finger, and the flexible mechanical finger is used to grasp fruit.

[0007] Preferably, the rotating mechanism includes a rotating motor, a motor base, and a shaft cylinder. The rotating motor is mounted on the motor base, and the rotating shaft of the rotating motor is connected to the bracket of the bending mechanism through the shaft cylinder.

[0008] Preferably, the motor base is provided with a housing, the rotating motor is disposed inside the housing, a support ring is provided between the shaft and the motor base, and a thrust bearing is disposed inside the support ring.

[0009] Preferably, the folding mechanism includes a support, a grooved cam, a linkage mechanism, and a drive mechanism. The support is an L-shaped support, the base plate of the support is connected to the rotating mechanism, and a U-shaped notch is provided on the side plate. The drive mechanism is provided on the U-shaped notch and is connected to the linkage mechanism. The clamping mechanism is connected to the grooved cam on the support through the linkage mechanism. The grooved cam is fixedly connected to the slide of the clamping mechanism. The linkage mechanism can cause the grooved cam to rotate at least 15°.

[0010] Preferably, the lower end of the grooved cam is provided with an irregular groove, a wheel axle is provided in the irregular groove, a roller is sleeved on the wheel axle, the roller is located in the irregular groove, and both ends of the wheel axle are hinged to the linkage mechanism.

[0011] Preferably, the linkage mechanism includes a swing arm and a drive arm, which are symmetrically arranged on both sides of the grooved cam. The swing arm includes a rocker arm and a support arm. The two ends of the rocker arm are respectively hinged to the base plate of the L-shaped bracket and the mounting seat of the clamping mechanism. One end of the support arm is hinged to the end hinge shaft of the support arm, and the other end is hinged to the wheel axle. The drive arm includes a long arm and a short arm. The two ends of the short arm are respectively hinged to the middle of the long arm and the wheel axle. The two ends of the long arm are respectively hinged to the side plate of the L-shaped bracket and the middle of the mounting seat.

[0012] Preferably, the drive mechanism includes a motor, a worm gear, and a worm. The motor is connected to the worm, the worm meshes with the worm gear, and the two ends of the worm gear's shaft pass through the U-shaped notch and are fixed to the lower end of the long arm.

[0013] Preferably, the clamping mechanism includes a mounting base, a slide, a guide rod, and a telescopic rod. The mounting base is slidably disposed with the central hole of the slide via the guide rod. The mounting base is located between the grooved cam and the slide. Four flexible mechanical fingers are hinged to the four corners of the slide. The four corners of the mounting base are hinged to the outer bottom corners of the flexible mechanical fingers via the telescopic rod.

[0014] Preferably, both ends of the slide are fixedly connected to the grooved cam via connecting plates, and the connecting plates pass through the mounting base.

[0015] Preferably, the flexible mechanical finger includes a finger base and a flexible finger, wherein the finger base is provided with an isosceles triangular flexible finger, and the interior of the flexible finger is provided with a strip-shaped hollow.

[0016] The present invention achieves the following technical effects compared to the prior art:

[0017] This invention integrates the picking action into the end effector of the picking robot. Compared with the traditional six-axis robotic arm, it significantly reduces the difficulty of controlling the robotic arm and the overall design difficulty of the picking robot, making it more suitable for fruit picking in trellis pear orchards. It enables the actuator to perform clamping and picking actions, with a simple and low-cost mechanism that is easy to operate and improves picking efficiency. Attached Figure Description

[0018] 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.

[0019] Figure 1 This is a schematic diagram of the end effector of the harvesting robot of the present invention;

[0020] Figure 2 This is a schematic diagram of the initial state of the end effector of the harvesting robot of the present invention;

[0021] Figure 3 This is a schematic diagram of the final state of the end effector of the harvesting robot of the present invention;

[0022] Figure 4 This is a schematic diagram of the internal structure of the branching mechanism in this invention;

[0023] Figure 5 This is a schematic diagram of the principle of the branching mechanism in this invention. Figure 1 ;

[0024] Figure 6 This is a schematic diagram of the principle of the branching mechanism in this invention. Figure 2 ;

[0025] Among them: 1-flexible finger, 2-telescopic rod, 3-mounting seat, 4-groove cam, 5-bracket, 6-shaft cylinder, 7-machine housing, 8-rotating motor, 9-motor seat, 10-support ring, 11-support arm, 12-long arm, 13-slide seat, 14-finger seat, 15-swing arm, 16-short arm, 17-connecting plate, 18-worm gear, 19-worm, 20-coupling, 21-motor, 22-locking nut, 23-rotating shaft, 24-roller, 25-axle. Detailed Implementation

[0026] 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.

[0027] The purpose of this invention is to provide an end effector for a harvesting robot to solve the problems existing in the prior art, enabling the actuator to perform clamping and harvesting actions. The mechanism is simple and low-cost, easy to operate, and improves harvesting efficiency.

[0028] 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.

[0029] like Figures 1 to 6 As shown: This embodiment provides an end effector for a harvesting robot, including a flexible mechanical finger, a clamping mechanism, a branch-breaking mechanism, and a rotating mechanism. The rotating mechanism is used to connect to the harvesting robot. The branch-breaking mechanism is rotatably connected to the rotating mechanism. The branch-breaking mechanism is provided with a clamping mechanism. The flexible mechanical finger is connected to the clamping mechanism. The clamping mechanism can open or close the flexible mechanical finger, which is used to grasp the fruit.

[0030] The rotating mechanism includes a rotating motor 8, a motor base 9, and a shaft cylinder 6. The rotating motor 8 is mounted on the motor base 9, and its shaft is connected to the bracket 5 of the branch-breaking mechanism via the shaft cylinder 6. A housing 7 is mounted on the motor base 9, and the rotating motor 8 is housed within the housing 7. A support ring 10 is positioned between the shaft cylinder 6 and the motor base 9, and a thrust bearing is installed within the support ring 10. The thrust bearing forms a rotating pair between the shaft cylinder 6 and the motor base 9. The rotating motor 8 is a servo motor, used to adjust the direction of the picking action, preventing it from hitting branches during fruit picking and thus ensuring the fruit is picked directly. The support ring 10 is fixed to the L-shaped motor base 9 with three bolts and to the rotating motor 8 with four bolts. The housing 7 is fixed to the motor base 9 with four bolts. The motor base 9 has eight pre-drilled bolt holes for connecting the robotic arm of the picking robot.

[0031] The branch-breaking mechanism includes a support 5, a grooved cam 4, a linkage mechanism, and a drive mechanism. The support 5 is an L-shaped support. The base plate of the support 5 is connected to the rotating mechanism, and a U-shaped notch is provided on the side plate. The drive mechanism is provided on the U-shaped notch and is connected to the linkage mechanism. The clamping mechanism is connected to the grooved cam 4 on the support 5 through the linkage mechanism. The grooved cam 4 is fixedly connected to the slide 13 of the clamping mechanism. The linkage mechanism can make the grooved cam 4 rotate at least 15°, which facilitates the action of breaking the fruit and breaking the fruit stem. The lower end of the grooved cam is provided with an irregular groove, which includes a straight section and a slope section. A wheel axle 25 is provided in the irregular groove, and a roller 24 is sleeved on the wheel axle 25. The roller 24 is located in the irregular groove, and the two ends of the wheel axle 25 are hinged to the linkage mechanism. The linkage mechanism includes a swing arm and a drive arm, which are symmetrically arranged on both sides of the slotted cam 4. The swing arm includes a swing arm 15 and a support arm 11. The two ends of the swing arm 15 are respectively hinged to the base plate of the L-shaped bracket and the mounting seat 3 of the clamping mechanism. One end of the support arm 11 is hinged to the end hinge shaft of the support arm 11, and the other end is hinged to the wheel axle 25. The drive arm includes a long arm 12 and a short arm 16. The two ends of the short arm 16 are respectively hinged to the middle of the long arm 12 and the wheel axle 25. The two ends of the long arm 12 are respectively hinged to the side plate of the L-shaped bracket and the middle of the mounting seat 3. The drive mechanism includes a motor 21, a worm gear 18, and a worm 19. The motor 21 is connected to the worm 19, and the worm 19 meshes with the worm gear 18. The two ends of the rotating shaft 23 of the worm gear 18 pass through U-shaped notches and are fixed to the lower end of the long arm 12 by locking nuts 22. The motor 21 is a servo motor.

[0032] like Figure 4 As shown, the cam groove contour is composed of straight lines and arcs. The radius of curvature of the arc is the same as the movement trajectory of the roller 24. Therefore, at the beginning of the movement, the contact contour between the roller 24 and the grooved cam 4 is a straight line. The roller 24 drives the grooved cam 4 to move downward. The grooved cam 4 pulls the slide block 13 downward through the connecting plate 17. The slide block 13 drives the flexible mechanical finger 1 to rotate, realizing the clamping action. After moving a short distance, the contact contour between the roller 24 and the grooved cam 4 becomes an arc segment. Since the curvature of the arc segment of the grooved cam 4 is the same as the movement trajectory of the roller 24, the slide block 13 remains stationary during this movement, stopping the clamping. The long arm 12, the mounting base 3, and the support arm 11 continue to move, realizing the action of prying a fruit from bottom to top. It will not pull the fruit downward, avoiding the fruit falling off due to downward pulling or rotation, which can easily cause the fruit stem to separate from the fruit.

[0033] The clamping mechanism includes a mounting base 3, a slide 13, a guide rod, and a telescopic rod 2. The mounting base 3 is slidably mounted to the central hole of the slide 13 via the guide rod. The mounting base 3 is located between the slotted cam 4 and the slide 13. Four flexible mechanical fingers are hinged to the four corners of the slide 13. The four corners of the mounting base 3 are hinged to the outer bottom corners of the flexible mechanical fingers via the telescopic rod 2. The telescopic rod 2 can be a hydraulic rod, a pneumatic rod, or an electric push rod. The two ends of the slide 13 are fixedly connected to the slotted cam 4 via a connecting plate 17, which passes through the mounting base 3. The flexible mechanical fingers include a finger seat 14 and a flexible finger 1. The finger seat 14 is provided with an isosceles triangular flexible finger 1. The interior of the flexible finger 1 has a strip-shaped hollow. The material of the flexible finger 1 is silicone. In this embodiment, the stroke of the flexible mechanical finger gripper is determined by the cam profile. Its design is suitable for most sizes of pears. However, for some particularly large pears, there may be over-clamping, which may cause damage to the pear. Therefore, the finger seat 14 and the base plate are connected by a telescopic rod 2. The telescopic rod 2 is a hydraulic rod. The pressure is controlled by the overflow valve in the hydraulic system. The maximum pressure value in the hydraulic system before the pear is damaged can be set. When the maximum pressure value set in the hydraulic system is reached, the telescopic rod 2 extends and retracts, thereby stopping the clamping and avoiding damage to the pear during the harvesting process.

[0034] This example uses the harvesting of trellis-grown pears as an example to illustrate the specific motion process of the harvesting robot's end effector as follows:

[0035] Since trellis-grown pears typically grow vertically downwards, the initial state of the end effector in this example is as follows: Figure 2 As shown, the flexible mechanical fingers are vertically upward and open, while the long arm 12 and the mounting base 3 are placed horizontally. When the vision system of the pear-picking robot locates the target pear, the robotic arm drives the end effector to directly below the target pear. Based on the direction of the branches identified by the vision system, the gripping angle of the end effector is adjusted by rotating the motor 8 to avoid collisions during the picking process. After adjustment, the motor 21 starts to rotate, driving the worm gear 18 and worm 19 through the coupling 20. The worm gear 18 drives the slender rotating shaft 23 to rotate counterclockwise through the key, which in turn drives the long arm 12 to rotate counterclockwise, causing the mounting base 3 to move upward, driving the swing arm 15, support arm 11, short arm 16 and wheel axle 25 to rotate. The trajectory of the roller 24 is a circle with the upper rotating joint of the swing arm 15 as the center and the length of the swing arm 15 as the radius. The slide 13 remains stationary and stops clamping, while the long arm 12, mounting base 3 and support arm 11 continue to move, realizing an upward breaking action of the fruit.

[0036] like Figure 5 and Figure 6The simplified diagram of the mechanism shown illustrates the motion principle of the end effector implemented in this example. Analyzing it using the simplified diagram, it can be simplified into six links: a, b, c, d, e, and f. Among them, O1, O2, O3, O4, O5, O6, O7, and O8 are lower pairs, and O9 is a higher pair. Therefore, the degree of freedom of the entire mechanism can be calculated using the formula: F = 3n - 2pl - ph = 3 × 6 - 2 × 8 - 1 = 1. Thus, this mechanism has only one degree of freedom, and the entire mechanism can be driven by a single actuator.

[0037] The end effector of the trellis-type harvesting robot in this embodiment integrates the harvesting action into the end effector. Compared with traditional six-axis robotic arms, this significantly reduces the difficulty of robotic arm control. The harvesting robot design can be realized with a minimum of three degrees of freedom (XYZ), reducing the overall design difficulty of the harvesting robot and making it more suitable for fruit harvesting in trellis-type pear orchards. The end effector can realize both harvesting and clamping actions. It adopts a combination of linkage and cam mechanism, and the cam's irregular groove profile is reasonably designed to simultaneously realize clamping and harvesting actions. Compared with other end effectors, it has lower cost, easier development, and higher harvesting efficiency. The harvesting action of the end effector is an upward prying method, which is suitable for the special harvesting characteristics of fruits such as pears. The upward prying detachment method protects the pear stem and reduces the maximum force required for harvesting. It avoids the fruit falling off due to downward pulling or rotation, which can easily cause the stem to separate from the fruit and accelerate fruit decay. At the same time, these methods require greater force.

[0038] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An end effector for a harvesting robot, characterized in that: It includes a flexible mechanical finger, a clamping mechanism, a branch-breaking mechanism, and a rotating mechanism. The rotating mechanism is used to connect to the harvesting robot. The branch-breaking mechanism is rotatably connected to the rotating mechanism. The clamping mechanism is provided on the branch-breaking mechanism. The flexible mechanical finger is connected to the clamping mechanism. The clamping mechanism can open or close the flexible mechanical finger. The flexible mechanical finger is used to grasp the fruit. The folding mechanism includes a bracket, a grooved cam, a linkage mechanism, and a drive mechanism. The bracket is an L-shaped bracket. The lower end of the grooved cam has an irregular groove, and a wheel axle is disposed within the irregular groove. A roller is fitted on the wheel axle, and the roller is located within the irregular groove. Both ends of the wheel axle are hinged to the linkage mechanism. The linkage mechanism includes a swing arm and a drive arm, which are symmetrically arranged on both sides of the grooved cam. The swing arm includes a swing arm and a support arm. Both ends of the swing arm are hinged to the base plate of the L-shaped bracket and the mounting seat of the clamping mechanism, respectively. One end of the support arm is hinged to the end hinge shaft of the support arm, and the other end is hinged to the wheel axle. The drive arm includes a long arm and a short arm. Both ends of the short arm are hinged to the middle of the long arm and the wheel axle, respectively. Both ends of the long arm are hinged to the side plate of the L-shaped bracket and the middle of the mounting seat, respectively.

2. The end effector of the harvesting robot according to claim 1, characterized in that: The rotating mechanism includes a rotating motor, a motor base, and a shaft cylinder. The rotating motor is mounted on the motor base, and the rotating shaft of the rotating motor is connected to the bracket of the bending mechanism through the shaft cylinder.

3. The end effector of the harvesting robot according to claim 2, characterized in that: The motor base is provided with a housing, the rotating motor is disposed inside the housing, a support ring is provided between the shaft and the motor base, and a thrust bearing is disposed inside the support ring.

4. The end effector of the harvesting robot according to claim 1, characterized in that: The base plate of the bracket is connected to the rotating mechanism, and a U-shaped notch is provided on the side plate. The driving mechanism is provided on the U-shaped notch. The driving mechanism is connected to the linkage mechanism. The clamping mechanism is connected to the slotted cam on the bracket through the linkage mechanism. The slotted cam is fixedly connected to the slide of the clamping mechanism. The linkage mechanism can make the slotted cam rotate at least 15°.

5. The end effector of the harvesting robot according to claim 4, characterized in that: The drive mechanism includes a motor, a worm gear, and a worm. The motor is connected to the worm, and the worm meshes with the worm gear. The two ends of the worm gear's shaft pass through the U-shaped notch and are fixed to the lower end of the long arm.

6. The end effector of the harvesting robot according to claim 1, characterized in that: The clamping mechanism includes a mounting base, a slide, a guide rod, and a telescopic rod. The mounting base is slidably disposed with the central hole of the slide via the guide rod. The mounting base is located between the grooved cam and the slide. Four flexible mechanical fingers are hinged to the four corners of the slide. The four corners of the mounting base are hinged to the outer bottom corners of the flexible mechanical fingers via the telescopic rod.

7. The end effector of the harvesting robot according to claim 6, characterized in that: Both ends of the slide are fixedly connected to the grooved cam via connecting plates, and the connecting plates pass through the mounting base.

8. The end effector of the harvesting robot according to claim 1, characterized in that: The flexible mechanical finger includes a finger base and a flexible finger. The finger base is provided with an isosceles triangular flexible finger, and the interior of the flexible finger is provided with a strip-shaped hollow.

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