Strawberry picking end effector and working method thereof

Abstract

The application discloses a strawberry picking end effector and a working method thereof. The effector comprises a grabbing mechanism, an electric scissors mechanism and a controller. The electric scissors mechanism comprises a scissors frame, a micro electric push rod and a scissors connecting rod. The scissors frame comprises two symmetrically arranged X-shaped cross rods. The two ends of the same side of the two X-shaped cross rods are connected by one scissors connecting rod. The two ends of the same side of the two scissors connecting rods are connected by one micro electric push rod. The grabbing mechanism is arranged between the two X-shaped cross rods. The grabbing mechanism comprises a mechanical palm and pneumatic fingers. The mechanical palm is installed in the middle of the scissors frame. The pneumatic fingers are arranged on one side of the mechanical palm in a plurality of and circumferential arrangement. The pneumatic fingers are located on one side of the cutting part of the scissors frame. In the application, the pneumatic flexible mechanical fingers are used to grab the strawberries, so that the picking process is beneficial to avoid the mechanical damage of the strawberries.

Description

TECHNICAL FIELD

[0001] The present application relates to a strawberry picker, in particular to a strawberry picking end effector and its working method. BACKGROUND

[0002] The planting and picking of strawberries is a typical labor-intensive work. With the progress of agricultural breeding and cultivation technology, strawberry planting has been popularized, and the domestic strawberry planting area has rapidly increased. Therefore, the lack of labor is serious, especially the requirement for timeliness in the process of strawberry picking, which has put forward strict requirements for traditional manual picking, which has seriously restricted the further development of strawberry planting.

[0003] At present, domestic and foreign technical personnel have begun to develop strawberry picking robots, and the strawberry picking manipulator (also known as the strawberry picking end effector) is one of the key technologies of the strawberry picking robot.

[0004] Patent CN201821727624.3 discloses an end effector of a strawberry picking robot. The clamping object of this end effector is the root of the strawberry, and there is no sensor on the effector. This is very demanding on the control of the end effector and the visual technology of the picking object: because the end effector requires not only to know the position of the strawberry, but also to know the direction of the root of the strawberry, and also needs to rely on visual technology to determine whether the root is clamped. If the direction of the root of the strawberry is not appropriate during clamping, the scissor arm of the end effector may not be able to cut the strawberry stem. The grasping mechanism disclosed in patent CN201810498109.0 also has similar problems. SUMMARY

[0005] The purpose of the present application is to provide a strawberry picking end effector to provide technical support for the technical development of strawberry picking and other fruit picking robots. And its working method is disclosed.

[0006] Technical scheme: A strawberry picking end effector, comprising a grasping mechanism, an electric scissor mechanism and a controller, the electric scissor mechanism comprising a scissor frame, a micro electric push rod and a scissor connecting rod, the scissor frame comprising two X-shaped cross rods arranged symmetrically, the two ends of the same side of the two X-shaped cross rods being connected by a scissor connecting rod, the two ends of the same side of the two scissor connecting rods being connected by a micro electric push rod, the grasping mechanism being arranged between the two X-shaped cross rods, the grasping mechanism comprising a mechanical palm and a pneumatic finger, the mechanical palm being installed in the middle of the scissor frame, the pneumatic finger being installed on one side of the mechanical palm and arranged in a circumferential direction, the pneumatic finger being located on one side of the cutting part of the scissor frame, and the micro electric push rod and the grasping mechanism being signal connected with the controller.

[0007] Furthermore, the robotic hand includes a hand body, which is a cylindrical structure with a robotic hand air chamber in its middle. The outer circumference of the hand body is provided with an air chamber ventilation interface that communicates with the robotic hand air chamber. An air pipe is connected to the air chamber ventilation interface through an air pipe connector. One end face of the hand body is provided with multiple pneumatic finger connection holes for installing pneumatic fingers. The pneumatic finger connection holes communicate with the robotic hand air chamber. The hand body is also provided with a through scissor pivot mounting hole along the radial direction for connecting with the scissor frame.

[0008] Ideally, the air tube is connected to the gas cylinder through the valve body, and the valve body is connected to the controller signal.

[0009] Ideally, multiple wrist connection threaded holes are spaced apart on the other end face of the hand body, and the external robotic arm is threadedly connected to the hand body through the wrist connection threaded holes.

[0010] Furthermore, the pneumatic finger includes a finger root joint, a corrugated rubber tube, a silicone plate, a finger joint, and a fingertip micro switch. One end of the finger root joint is connected to the mechanical hand, and the silicone plate is perpendicularly connected to the other end face of the finger root joint. The outer circumferential surface of the corrugated rubber tube is connected to one side of the silicone plate, one end of which is connected to the finger root joint, and the other end is equipped with a fingertip micro switch. There is at least one finger joint. The corrugated rubber tube is cut into at least two segments along its length. The middle part of the finger joint is a through structure, so that each segment of the corrugated rubber tube is interconnected.

[0011] Ideally, the fingertip micro switch is connected to the controller signal via a micro switch wire. There are three pneumatic fingers, and the silicone plates on each pneumatic finger are arranged facing inwards.

[0012] Furthermore, the gripping mechanism also includes a scissor limiting shaft, which is laterally inserted into and connected to the palm of the robotic arm.

[0013] The scissor limiting shaft and the robotic hand are connected through the hole in the robotic hand. Since the upper and lower parts of the scissor frame are integrated and can rotate around the scissor pivot, the rotation angle of the lower part of the scissor frame is limited by limiting the rotation angle of the upper part of the scissor frame through the scissor limiting shaft.

[0014] Furthermore, the scissor frame also includes a scissor pivot, with its two ends connected to the intersection of two X-shaped crossbars. The other two ends of the two X-shaped crossbars are connected by a scissor blade plate, with the blades of the scissor blade plate facing the pneumatic fingers. The mechanical hand is connected to the scissor pivot.

[0015] Furthermore, the miniature electric actuator is connected to the controller signal via actuator wires.

[0016] A method for operating the above-mentioned strawberry picking end effector includes the following steps:

[0017] Step 1: Move the actuator directly above the strawberries and then move it vertically downwards until the pneumatic fingers touch the strawberry ridges;

[0018] Step 2: Use pneumatic fingers to bend inwards and grasp the strawberry;

[0019] Step 3: Move the actuator vertically upwards, and the miniature electric push rod will bring the electric shear mechanism together to cut the strawberry stem.

[0020] The pneumatic fingers bend by sensing the pressure inside them. As long as the gas pressure inside the pneumatic fingers reaches the set value, the strawberries will not be damaged.

[0021] Beneficial effects: Compared with the prior art, the advantages of the present invention are: (1) The present invention uses strawberries as the grasping object, which is easier to implement with visual technology than the prior art which uses roots and stems as the grasping object.

[0022] (2) In this invention, the strawberry is grasped by pneumatic flexible mechanical fingers, which helps to avoid mechanical damage to the strawberry during the picking process.

[0023] (3) The mechanical finger in this invention is equipped with a micro switch, which facilitates the intelligentization of the strawberry grasping process.

[0024] (4) The pneumatic fingers adopt "corrugated tube + finger joint", which can achieve a large degree of bending of the fingers and ensure the successful completion of strawberry picking.

[0025] (5) The present invention uses electric shears, which have a simple structure and facilitate the automation of strawberry root cutting. Attached Figure Description

[0026] Fig. 1 This is a three-dimensional structural diagram of the present invention;

[0027] Fig. 2 This is a schematic diagram of the structure of a pneumatic finger;

[0028] Fig. 3 A schematic diagram of the three-view structure of the grasping mechanism;

[0029] Fig. 4 This is a schematic diagram of the electric scissors mechanism;

[0030] Fig. 5 A schematic diagram of the structure of a robotic hand;

[0031] Fig. 6 This is a flowchart illustrating the strawberry harvesting process of the present invention. Detailed Implementation

[0032] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0033] A strawberry picking end effector, such as Figs. 1-6 As shown, the device includes a gripping mechanism, an electric scissor mechanism, and a controller. The electric scissor mechanism includes a scissor frame 12, a miniature electric push rod 14, and a scissor connecting rod 15. The scissor frame 12 includes two symmetrically spaced X-shaped crossbars. The two ends on the same side of the two X-shaped crossbars are connected by a scissor connecting rod 15, and the two ends on the same side of the two scissor connecting rods 15 are connected by a miniature electric push rod 14. The scissor connecting rods 15 are installed at both ends of the scissor frame to fix the scissor frame. The scissor frame can rotate around the scissor pivot under the action of the miniature electric push rod 14.

[0034] The gripping mechanism is positioned between two X-shaped crossbars and includes a robotic hand 1 and pneumatic fingers. The robotic hand 1 is mounted in the middle of the scissor frame 12. The robotic hand 1 includes a hand body, which is a cylindrical structure with a robotic hand air chamber 1-1 in its center. An air chamber ventilation interface 1-2 communicating with the robotic hand air chamber 1-1 is provided on the outer circumference of the hand body. An air pipe 9 is connected to the air chamber ventilation interface 1-2 via an air pipe connector 8. The air pipe 9 is connected to an air cylinder via a valve body, which is connected to a controller signal. One end face of the hand body has multiple pneumatic finger connection holes 1-3 for mounting pneumatic fingers, which communicate with the robotic hand air chamber 1-1. The hand body also has radially extending scissor pivot mounting holes 1-5 for connecting to the scissor frame 12. The other end face of the hand body also has multiple wrist connection threaded holes 1-4 spaced apart, through which an external robotic arm is threadedly connected to the hand body.

[0035] Multiple pneumatic fingers are installed at intervals on one side of the robotic hand 1 and arranged circumferentially. The pneumatic fingers are located on one side of the cutting part on the scissor frame 12. Each pneumatic finger includes a finger root joint 2, a corrugated rubber tube 3, a silicone plate 4, a finger joint 5, and a fingertip micro switch 6. One end of the finger root joint 2 is connected to the robotic hand 1, and the silicone plate 4 is perpendicularly connected to the other end of the finger root joint 2. The outer circumference of the corrugated rubber tube 3 is connected to one side of the silicone plate 4, and one end of the tube is connected to the finger root joint 2. The other end is equipped with a fingertip micro switch 6, which is connected to the controller signal via a micro switch wire 7. There are three pneumatic fingers, and the silicone plates 4 on each pneumatic finger are arranged facing inwards. There is at least one finger joint 5, which is arranged along the length of the corrugated rubber tube 3, cutting the tube 3 into at least two segments. The middle of the finger joint 5 is a through structure, allowing each segment of the corrugated rubber tube 3 to be interconnected.

[0036] The air chamber 1-1 of the robotic hand can evenly distribute the gas in the air tube 9 to the three pneumatic fingers through the air chamber ventilation port 1-2.

[0037] The scissor holder 12 also includes a scissor pivot 10. The two ends of the scissor pivot 10 are respectively connected to the intersection of two X-shaped cross rods. The two ends of the other side of the two X-shaped cross rods are respectively connected by a scissor blade plate 12-1. The blade of the scissor blade plate 12-1 faces the pneumatic finger. The mechanical hand 1 is connected to the scissor pivot 10.

[0038] The miniature electric actuator 14 and the gripping mechanism are respectively connected to the controller via signal connections. The gripping mechanism also includes a scissor limiting shaft 13, which is transversely inserted into and connected to the robotic hand 1. The miniature electric actuator 14 is connected to the controller via an actuator wire 16.

[0039] The working method of the strawberry picking end effector described above includes the following steps:

[0040] Step 1: Move the actuator directly above the strawberries and then move it vertically downwards until the pneumatic fingers touch the strawberry ridges;

[0041] Step 2: Use pneumatic fingers to bend inwards and grasp the strawberry;

[0042] Step 3: Move the actuator vertically upwards, and the miniature electric push rod will bring the electric shear mechanism together to cut the strawberry stem.

[0043] During the harvesting process, when the strawberry picking robot approaches the strawberry, the fingertip microswitch is activated when it touches the strawberry ridge. At this time, the air tube simultaneously provides pressurized gas to the three pneumatic fingers through the robot's palm, causing the corrugated rubber tube to extend and bend to grasp the strawberry. When the strawberry picking robot is raised to a set distance, the miniature electric push rod pushes the scissor frame to close, cutting the strawberry stem and completing the strawberry harvest.

Claims

1. A strawberry picking end effector, characterized in that: The device includes a gripping mechanism, an electric scissor mechanism, and a controller. The electric scissor mechanism includes a scissor frame (12), a miniature electric push rod (14), and a scissor connecting rod (15). The scissor frame (12) includes two symmetrically spaced X-shaped cross rods. The two ends of the same side of the two X-shaped cross rods are connected by a scissor connecting rod (15). The two ends of the same side of the two scissor connecting rods (15) are connected by a miniature electric push rod (14). The gripping mechanism is located between the two X-shaped cross rods. The gripping mechanism includes a mechanical hand (1) and pneumatic fingers. The mechanical hand (1) is installed in the middle of the scissor frame (12). Multiple pneumatic fingers are installed at intervals on one side of the mechanical hand (1) and arranged in a circumferential direction. The pneumatic fingers are located on one side of the cutting part on the scissor frame (12). The miniature electric push rod (14) and the gripping mechanism are respectively connected to the controller signal. The mechanical hand (1) includes a hand body, which is a cylindrical structure. The middle part of the hand body is provided with a mechanical hand air chamber (1-1). The outer circumferential surface of the hand body is provided with an air chamber ventilation interface (1-2) that communicates with the mechanical hand air chamber (1-1). The air pipe (9) is connected to the air chamber ventilation interface (1-2) through the air pipe connector (8). One end face of the hand body is provided with multiple pneumatic finger connection holes (1-3) for installing pneumatic fingers. The pneumatic finger connection holes (1-3) communicate with the mechanical hand air chamber (1-1). The hand body is also provided with a through scissor pivot mounting hole (1-5) along the radial direction for connecting with the scissor frame (12). The pneumatic finger includes a finger root joint (2), a corrugated rubber tube (3), a silicone plate (4), a finger joint (5), and a fingertip micro switch (6). One end of the finger root joint (2) is connected to the mechanical hand (1). The silicone plate (4) is perpendicularly connected to the other end face of the finger root joint (2). The outer circumferential surface of the corrugated rubber tube (3) is connected to one side of the silicone plate (4). One end of the corrugated rubber tube (3) is connected to the finger root joint (2), and the other end is equipped with a fingertip micro switch (6). There is at least one finger joint (5). The corrugated rubber tube (3) is cut into at least two sections along the length direction of the corrugated rubber tube (3). The middle part of the finger joint (5) is a through structure, so that each section of the corrugated rubber tube (3) is connected to each other. The fingertip micro switch (6) is connected to the controller signal via the micro switch wire (7). There are three pneumatic fingers, and the silicone plates (4) on each pneumatic finger are arranged facing inwards. The scissor frame (12) also includes a scissor pivot (10), the two ends of which are connected to the intersection of two X-shaped cross rods respectively. The two ends of the other side of the two X-shaped cross rods are connected by a scissor blade plate (12-1) respectively. The blade of the scissor blade plate (12-1) faces the pneumatic finger. The mechanical hand (1) is connected to the scissor pivot (10).

2. The strawberry picking end effector according to claim 1, characterized in that: The air tube (9) is connected to the gas cylinder through the valve body, and the valve body is connected to the controller signal.

3. The strawberry picking end effector according to claim 1, characterized in that: On the other end face of the hand body, there are also a number of wrist connection threaded holes (1-4) spaced apart. The external robotic arm is threadedly connected to the hand body through the wrist connection threaded holes (1-4).

4. The strawberry picking end effector according to claim 1, characterized in that: The gripping mechanism also includes a scissor limiting shaft (13), which is transversely inserted into and connected to the mechanical hand (1).

5. A strawberry picking end effector according to claim 1, characterized in that: The miniature electric actuator (14) is connected to the controller signal via actuator wire (16).

6. A method for operating the strawberry picking end effector as described in any one of claims 1 to 5, characterized in that... Includes the following steps: Step 1: Move the actuator directly above the strawberries and then move it vertically downwards until the pneumatic fingers touch the strawberry ridges; Step 2: Use pneumatic fingers to bend inwards and grasp the strawberry; Step 3: Move the actuator vertically upwards, and the miniature electric push rod will bring the electric shear mechanism together to cut the strawberry stem.

Images