CN110972719A

CN110972719A - Automatic end effector of picking of formula kiwi fruit is swayd to fruit handle

Info

Publication number: CN110972719A
Application number: CN202010029040.4A
Authority: CN
Inventors: 崔永杰; 文双涛; 王明辉; 张鑫宇; 崔功佩; 卫咏哲; 穆龙涛
Original assignee: Northwest A&F University
Current assignee: Northwest A&F University
Priority date: 2020-01-12
Filing date: 2020-01-12
Publication date: 2020-04-10

Abstract

The invention discloses a fruit handle swing type kiwi fruit automatic picking end effector which comprises a proximity mechanism, a clamping mechanism, a swing picking mechanism, a sensing system and a control system. The approaching mechanism drives the clamping mechanism to horizontally move and vertically move to finish the action of approaching the fruit from the lower part. The sensing system detects whether the fruit handle enters between two oppositely arranged fingers, and the cylinder drives the fingers to move to clamp the fruit handle and keep for a certain time. The swinging picking mechanism realizes the swinging action of fruits by combining the linear motion of the air cylinder and the rotary motion of the stepping motor, and realizes the separation by means of inertia in the movement process of the kiwi fruits. The control system controls the whole picking process according to the feedback information of the sensor. The kiwi fruit picking machine is simple in structure and convenient to use, reduces the kiwi fruit falling damage degree, and improves the automatic kiwi fruit picking efficiency and success rate.

Description

Automatic end effector of picking of formula kiwi fruit is swayd to fruit handle

Technical Field

The invention relates to a fruit picking end effector, in particular to a kiwi fruit picking end effector, and belongs to the field of picking robots.

Background

At present, more and more picking robots are applied to agriculture, wherein the picking robots applied to the aspect of kiwi fruit harvesting are still to be further improved. The end effector of the existing kiwi fruit picking robot mainly clamps fruits firstly, then the end effector rotates or pulls to finish picking, the harvesting method can cause great damage to kiwi fruits, the commercial value of the kiwi fruits is influenced, and meanwhile, negative influences can be caused on storage and transportation in the later period. In recent years, the development of automation technology is rapid, the application field is increased continuously, and the agricultural production life is also continuously closed to automation. The picking work of kiwi fruits is completed by adopting a robot instead of a human, the picking automation of kiwi fruits is realized, and the kiwi fruit picking machine has the advantages of saving manpower and material resources, increasing the added value of commodities, increasing the operation time and the like.

The end effector of the fruit and vegetable picking robot disclosed by the Chinese patent CN101019484A separates fruits by adopting a sucking disc adsorption mode, and the end effector is complicated in structural design and control due to the structure. Chinese patent CN102187766A discloses a kiwi picking end effector, which has limited picking of adjacent fruits due to its volume limitation.

In view of this, an end effector for picking kiwi fruits is needed, and the end effector is designed, has a simple structure and strong applicability, and can reduce the damage rate in the automatic picking process of kiwi fruits. The kiwi fruit picking end effector has the advantages that the kiwi fruit picking end effector can automatically approach and pick kiwi fruits adjacent to the kiwi fruits in the automatic picking process of kiwi fruits, and therefore, the kiwi fruit picking end effector has very important significance for developing a kiwi fruit picking robot and reducing the kiwi fruit harvesting cost.

Disclosure of Invention

In order to overcome the defects of the existing picking method and picking device, the invention provides the kiwi fruit nondestructive picking end effector which adopts a mechanical structure to realize reliable fruit separation.

The invention is realized by the following technical scheme:

a fruit handle swing type kiwi fruit automatic picking end effector comprises a proximity mechanism (3), a clamping mechanism (1), a swing picking mechanism (2), a sensing system (5) and a control system (4); wherein the clamping mechanism (1) comprises a front finger (101), a rear finger (102), a connecting piece (103) and a rod cylinder (104); the front finger (101) and the rear finger (102) are stepped sheet parts, rubber materials are attached to parts which are possibly contacted with fruits, the front ends of the front finger (101) and the rear finger (102) are provided with fine patterns for clamping fruit stalks, the slider (104) is driven by the rod cylinder (104) to move linearly to realize the opening and closing of the front finger and the rear finger, and the fruits are separated from the fruit stalks by swinging movement after the front finger (101) and the rear finger (102) are closed in the picking process; the swing picking mechanism (2) comprises a connecting block (204), a bracket (203), a guide rod (202), a stepping motor III (201), a rod cylinder (207) and the like, one end of the stepping motor III (201) is connected with the connecting block (204), the other end is connected with the clamping mechanism (1), one end of the guide rod (202) is connected with the stepping motor III (201), the two ends are fixed on the bracket (203), wherein the bracket (203) is connected with the approaching mechanism (3) and used for supporting and fixing the swinging picking mechanism (2), the rod cylinder (207) is used for driving the stepping motor III (201) and the clamping mechanism (1) to do linear motion in a telescopic way, meanwhile, the stepping motor III (201) rotates to drive the whole clamping mechanism (1) to rotate, so that the fruit and the fruit stem form an acute angle, the fruit handle is pulled off under the action of gravity, the rotation angle of the speed reduction stepping motor III (201) is set by a limit switch (404), and the position of the limit switch (404) is adjustable; the sliding block (304) horizontally slides along the transverse guide plate (308) under the driving of the stepping motor II (305) to enable the front finger (101) and the rear finger (102) to move to the lower part of the fruit, the sliding block (304) vertically slides along the vertical guide plate (302) under the driving of the stepping motor I (301) to enable the front finger to slowly approach the fruit handle of the fruit and stop rotating after reaching the picking position. The sensing system (5) comprises a pressure sensor (401), an infrared photoelectric switch sensor (402), Hall position sensors I (403) and II (405); the pressure sensor (401) is arranged on the inner side of the rear finger (102); the infrared photoelectric switch sensor (402) is fixed on the inner sides of the two fingers, wherein the rear finger (102) is provided with a transmitting end, and the front finger (101) is provided with a receiving end; the Hall position sensor I (403) is arranged on the connecting piece (103), and the Hall position sensor II (28) is arranged at one end of the transverse guide plate (308) of the approaching mechanism; and a limit switch (404) is arranged on the guide block (204) and used for detecting the rotation angle of the speed reducing stepping motor, and the position of the limit switch (404) is adjustable. The control system (4) is controlled by a single chip microcomputer and comprises a stepping motor driver I (503), a stepping motor driver II (502) and a stepping motor driver III (501); the single chip microcomputer controls the stepping motor driver I (503), the stepping motor driver II (502) and the stepping motor driver III (501) through the I/O, and receives sensor signals through a serial port to realize feedback control of the system.

Preferably, the size of the horizontal guide plate (308) and the vertical guide plate (302) of the approach mechanism (3) is 3000mm and 1000mm respectively, and different stepping motors are used for control respectively.

Preferably, the connecting block (204) in the swing picking mechanism (2) is a rectangular block with the size of 50mm multiplied by 50mm, and a through hole with the diameter of 10mm is arranged in the middle of the rectangular block and is connected with a guide rod with the length of 80mm and the diameter of 10 mm.

Preferably, the front fingers (101) and the rear fingers (102) are completely symmetrically arranged, are in a step shape, have three sections, are respectively 50mm multiplied by 80mm multiplied by 30mm in size, are made of plastic, and are externally attached with a layer of rubber material.

Preferably, the maximum opening distance of the front finger and the rear finger is 50mm, and the maximum opening distance can be adjusted according to different varieties of kiwi fruits.

Preferably, the length of the fine lines for clamping the carpopodium part by the front and the back fingers is 20mm, so that the carpopodium is prevented from sliding too much to be separated from the fingers in the movement process.

Preferably, the stroke of the connecting block of the swing picking mechanism is 20mm, the stepping motor can rotate forwards by 60 degrees and reversely by 60 degrees, and the control is carried out through a limit switch.

Compared with the prior art, the kiwi fruit picking end effector has the following beneficial effects:

the invention adopts single chip microcomputer control, aiming at the characteristic that kiwi fruits are adjacently grown, the clamping mechanism utilizes the length difference between the front ends of the front fingers and the rear fingers and the height difference between the front ends and the rear ends of the fingers, and the clamping mechanism rotates and moves linearly relative to the bracket, so that the front fingers and the rear fingers drive the fruit to perform swinging motion after completing the clamping process, the fingers approach the fruit from the bottom of the fruit, the separation of adjacent fruits and the grabbing of fruit stalks are effectively completed by adopting a mechanical structure, an inertia shaft of the fruit and the fruit stalks form an acute angle by adopting a swinging motion method, under the action of inertia force, the fruit handle is pulled off from the fruit base, the separating force of the fruit handle is reduced, the picking action is finished by controlling the swing amplitude of the end effector, the mechanical structure and the control are simplified, through the feedback control of the sensor, the control precision is improved, and the nondestructive picking of the fruits is realized.

Drawings

The patent is further described with reference to the drawings and the embodiments.

Fig. 1 is an overall structural schematic diagram of a stem-swing type kiwi fruit automatic picking end effector;

FIG. 2 is a schematic view of the two sides of the shaft of the present invention;

FIG. 3 is a schematic view of the gripping mechanism and the rocking picker mechanism of the present invention;

FIG. 4 is a schematic view of the proximity mechanism of the present invention;

the following are the component numbers in the figures:

preceding finger (101), back finger (102), connecting piece (103), there is pole cylinder (104), step motor III (201), guide arm (202), support (203), connecting block (204), round pin (205), connecting rod (206), there is pole cylinder (207), step motor I (301), vertical deflector (302), connecting piece (303), slider (304), step motor II (305), lead screw (306), flange (307), horizontal deflector (308), pressure sensor (401), infrared photoelectric switch sensor (402), hall position sensor I (403), hall position sensor II (404), step motor driver III (501), step motor driver II (502), step motor driver I (503).

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Referring to fig. 1, 2, 3 and 4, a fruit handle swing type automatic kiwi picking end effector consists of an approaching mechanism (3), a clamping mechanism (1), a swing picking mechanism (2), a sensing system (5) and a control system (4), wherein the clamping mechanism (1) comprises a connecting piece (103), a front finger (101), a rear finger (102) and a rod cylinder (104), the front finger (101) and the rear finger (102) of the clamping mechanism (1) are symmetrically arranged, the front ends of the front finger (101) and the rear finger (102) are provided with fine patterns with the same length, the front finger and the rear finger are connected with the connecting piece (103) through a pin, and the connecting piece (103) and the rod cylinder (104) are connected through a bolt and can drive the fingers to do linear motion; the approaching mechanism (3) comprises a transverse guide plate (308), a vertical guide plate (302), a connecting piece (303), a lead screw (306), a stepping motor II (305), a sliding block (304) and a flange (307), one end of the lead screw (306) is fixedly connected with the motor, the other end of the lead screw is connected with the transverse guide plate (308) through a bearing, the transverse guide plate (308) and the vertical guide plate (302) are vertically arranged, and the edge of the sliding block (304) is clamped in a guide plate sliding rail; swing picking mechanism (2) including step motor III (201), support (203), connecting rod (206), have pole cylinder (207), guide arm (202), connecting block (204), round pin (205), step motor III (201) and connecting block (204) pass through bolted connection, and through-hole in the middle of connecting block (204) is passed in guide arm (202), connecting rod (206) with have pole cylinder (207) fixed connection. A limit switch (404) is mounted on the connecting block (204), the limit switch (404) controls the rotation angle of the stepping motor III (201), and the rotation angle is adjusted by adjusting the position of the limit switch (404); the sensing system (5) comprises a pressure sensor (401), an infrared photoelectric switch sensor (402), a Hall position sensor I (403) and a Hall position sensor II (404); the pressure sensor (401) is arranged on the inner side of the back finger (102) and used for detecting the clamping force on the fruit stem; the infrared photoelectric switch sensor (402) is a correlation type combination, the rear finger (102) is provided with a transmitting end, and the front finger (101) is provided with a receiving end for detecting the position of the fruit; the Hall position sensor I (403) and the Hall position sensor II (404) are respectively arranged on the connecting plate (103) and the transverse guide plate (308) and are used for detecting reset information and preventing the mechanism from colliding; control system (4) are controlled by the singlechip, including step motor driver I (503), step motor driver II (502), step motor driver III (501), each driver passes through the bolt and connects with other components, receives the sensor signal through the serial ports, forms feedback control, reaches entire system's accurate positioning.

The specific working process is as follows:

1. resetting all parts, reversely rotating the stepping motor I and the stepping motor II, rotating the stepping motor III to a set angle, and after resetting is completed, stopping all motors to rotate and waiting for commands;

2. when the fruit is close to the fruit, the stepping motor II rotates forwards, the stepping motor II stops rotating after the end effector moves to the position right below the fruit, then the stepping motor I rotates forwards, the end effector slowly approaches the fruit from the lower part, and when the infrared photoelectric switch outputs a low level, the fruit handle is considered to enter between two fingers, and the stepping motor I stops rotating;

3. clamping the fruit stem, enabling the front finger and the rear finger to be close when the cylinder starts to push, stopping pushing when the pressure sensor detects that a preset pressure value is reached, and keeping a clamping state within a set time;

4. separating the fruit stalks, wherein in the separation process, the single chip microcomputer controls the air cylinder of the swing picking mechanism and the stepping motor III to work simultaneously, and the stepping motor III continuously rotates forwards and backwards within a preset angle range;

5. releasing the fruit handle and moving to the lower part of the next fruit, finishing the preset forward and reverse rotation times of the stepping motor within a preset angle, finishing the separation action of the fruit and the fruit handle, opening the fingers, resetting the stepping motor I, picking the next fruit, and completely resetting the motor until all the fruits provided by the computer are picked. The approaching mechanism, the clamping mechanism, the swinging picking mechanism, the sensing system and the control system work together to complete the picking process of the kiwi fruits. The pressure sensor is arranged on the rear finger, detects the clamping force during clamping, and prevents the fruit handle from being clamped off or the finger from being broken due to the fact that the fruit handle is too hard.

The installation positions of the stepping motor (201) and the rod cylinder (207) are mutually vertical, so that the fruits can be guaranteed to swing in the picking process.

The limit switch (404) is arranged below the stepping motor (201), so that the rotation angle of the stepping motor (201) can be effectively limited, and the fruit damage or the end effector damage caused by the fact that the fruit moves too violently due to the fact that the rotation angle exceeds a preset value is avoided.

When the approaching mechanism returns to the position (3), the vertical guide plate (302) is close to one side of the transverse guide plate (308) where the stepping motor (305) is installed, and the transverse guide plate (308) is close to one side of the vertical guide plate (302) far away from the stepping motor (301).

The outer sides of the front finger (101) and the rear finger (102) are respectively attached with a silica gel material to protect fruits.

The end effector is light in weight, except for standard parts, the front finger (101) and the rear finger (102) are made of plastic materials, and other supports and the like are made of aluminum alloy or stainless steel;

the end effector is simple in mechanism and convenient to control, has the functions of fruit separation, accurate grabbing and fruit handle separation, and provides key technical support for the kiwi fruit picking robot.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.

Claims

1. The utility model provides an end effector is picked automatically to fruit handle formula kiwi fruit that sways, its characterized in that, end effector is picked automatically to fruit handle formula kiwi fruit that sways includes proximity mechanism (3), fixture (1), sways picking mechanism (2), sensing system (5) and control system (4), wherein: the approaching mechanism (3) is composed of a transverse guide plate (308), a vertical guide plate (302), a connecting piece (303), a lead screw (306), a stepping motor I (301), a stepping motor II (305), a sliding block (304) and a flange (307), the transverse guide plate (308) and the vertical guide plate (302) are vertically installed, and the lead screw (306) is installed in the middle of the transverse guide plate (308); the clamping mechanism (1) comprises a connecting piece (103), a front finger (101), a rear finger (102), a rod cylinder (104) and the like; the front fingers (101) and the rear fingers (102) are identical in shape and size and symmetrically arranged, and are connected with the rod cylinders (104) through the connecting pieces (103), the rod cylinders (104) control the front fingers (101) and the rear fingers (102) to open and close through telescopic motion to clamp and loosen fruit handles, and the swing picking mechanism (2) comprises a stepping motor III (201), a support (203), a connecting rod (206), a rod cylinder (207), a guide rod (202), a connecting block (204), a pin (205) and the like; the connecting rod (206) penetrates through a hole in the middle of the connecting block (204), the connecting block (204) and the clamping mechanism (1) are driven to do linear motion by the rod cylinder (207), and the stepping motor III (201) drives the clamping device (1) to do rotary motion to synthesize the swinging motion of the clamping mechanism (1); the sensing system (5) comprises a pressure sensor (401), an infrared photoelectric switch sensor (402), a Hall position sensor (403) and a Hall position sensor II (404); the pressure sensor (401) is mounted inside the rear finger (102); the infrared photoelectric switch sensor (402) is a correlation type combination, a transmitting end is arranged on a rear finger (102), and a receiving end is arranged on a front finger (101); the control system (4) is controlled by a single chip microcomputer and consists of a stepping motor driver I (503), a stepping motor driver II (502) and a stepping motor driver III (501); the single chip microcomputer controls the stepping motor driver I (503), the stepping motor driver II (502) and the stepping motor driver III (501) through the I/O and receives sensor signals through a serial port.

2. The automatic picking end effector of fruit stem rocking kiwi fruit of claim 1, wherein: the front finger (101) and the rear finger (102) are in a step shape, the size of the two fingers is 50mm multiplied by 80mm multiplied by 30mm, the fruit stem clamping part is provided with fine patterns, the length of the patterns is 20mm, the length of the front end and the rear end of the fingers is slightly larger than the maximum diameter of the minor axis cross section of the fruit, and the fruit is ensured to have enough movement space and the fruit stem is prevented from sliding in the picking process.

3. The automatic picking end effector of fruit stem rocking kiwi fruit of claim 1, wherein: rubber materials are attached to the outer portions of the front finger (101) and the rear finger (102), and damage caused by collision of fruits and fingers is avoided.

4. The automatic picking end effector of fruit stem rocking kiwi fruit of claim 1, wherein: the front fingers (101) and the rear fingers (102) are made of plastic materials, are strip-shaped and small in size, can adapt to the characteristic that fruits grow adjacently, and are not affected by other adjacent fruits when fruit stalks are clamped.

5. The automatic picking end effector of fruit stem rocking kiwi fruit of claim 1, wherein: the swing type picking mechanism adopts a mode that a rod cylinder (21) and a stepping motor (201) are vertically arranged, and linear motion of a cylinder (207) and rotary motion of the stepping motor (201) are combined into swing motion of the clamping device (1).

6. The automatic picking end effector of fruit stem rocking kiwi fruit of claim 1, wherein: the connecting block (204) is a rectangular block with the size of 50mm multiplied by 50mm, the shape of the connecting block can ensure that the connecting block does not rotate in the moving process, a through hole with the diameter of 10mm is arranged in the middle, and a guide rod (202) with the length of 80mm penetrates through the through hole, so that the connecting block (204) is ensured to move linearly.

7. The automatic picking end effector of fruit stem rocking kiwi fruit of claim 1, wherein: the limiting block (404) is arranged below the stepping motor (104), the rotating angle of the stepping motor can be limited in the picking process, and meanwhile, the rotating angle of the stepping motor (104) can be changed by adjusting the position of the limiting block (404).