Expandable apple picking device and picking method thereof

Abstract

The invention discloses an expandable apple picking device and a picking method thereof, and relates to the technical field of picking machinery, including: a support tube, the lower end of the support tube is used to connect the mechanical arm of the picking robot; a flexible head body, the lower end of the flexible head body is fixed to the upper end of the support tube; an open arc ring, two open arc rings are relatively arranged at the upper end of the flexible head body; a displacement ring, the displacement ring is slidably connected to the outer wall of the support tube, and the displacement ring is connected with a linear drive device; an open push rod, the open push rod is two, the upper ends of the two open push rods are respectively hinged with the two open arc rings, and the lower ends of the two open push rods are hinged to the two ends of the displacement ring; a suction nozzle, the suction nozzle is installed on the flexible head body, one end of the suction nozzle is located in the inner cavity of the flexible head body, and the other end of the suction nozzle is connected with an air pump; a camera, the camera is arranged in the flexible head body; a controller, the camera and the air pump are both electrically connected to the controller. The invention can be applicable to the picking of single fruit or clustered fruit, and has high picking efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of picking machinery, and in particular to an expandable apple picking device and a picking method thereof. Background Art

[0002] As the labor-intensive part of apple orchard production management, harvesting accounts for about 33% to 50% of the total cost of apple production. With the aging of the population and the loss of a large number of agricultural workers, the problem of difficulty and high labor costs in apple picking has become increasingly prominent, which has seriously restricted the development of the apple industry. Therefore, it is imperative to develop efficient and low-loss mechanized automatic picking devices to replace manual operations.

[0003] At present, the existing mechanized apple picking devices can be roughly divided into three types: shaking type, auxiliary harvesting platform and robot. The former two have problems such as fragile fruits, inability to selectively harvest, low efficiency and manual dependence, which make it difficult to meet the actual market needs. The increasingly mature robot technology has shown great potential in achieving accurate and efficient apple picking, which has attracted the attention of universities, research institutions and enterprises to apple picking robots, and successfully developed a number of picking robots. However, these machines only focus on picking single fruits and ignore clustered apples, which undoubtedly increases the amount of manual labor and economic losses, and reduces the harvesting efficiency to a certain extent.

[0004] Therefore, there is an urgent need in the market for an expandable apple picking device and a picking method thereof to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide an expandable apple picking device and a picking method thereof, which are used to solve the technical problems existing in the above-mentioned prior art. A flexible head body and a suction nozzle with adaptive diameter adjustment are used to grab single fruits and clustered fruits, which greatly improves the practicality and picking efficiency of the grabbing mechanism. The entire process does not require human intervention and supervision, which is beneficial to the mechanization and intelligent development of the apple industry.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The invention discloses an expandable apple picking device, comprising:

[0008] A support tube, the lower end of which is used to connect to the mechanical arm of the picking robot;

[0009] A flexible head, the lower end of which is fixed to the upper end of the support tube;

[0010] An open arc ring, wherein there are two open arc rings, and the two open arc rings are arranged oppositely at the upper end of the flexible head body;

[0011] A displacement ring, wherein the displacement ring is slidably connected to the outer wall of the support tube, and the displacement ring is connected to a linear drive device, and the linear drive device drives the displacement ring to move up and down;

[0012] An opening push rod, wherein there are two opening push rods, the upper ends of the two opening push rods are respectively hinged to the two opening arc rings, and the lower ends of the two opening push rods are hinged to the two ends of the displacement ring;

[0013] A suction nozzle, wherein there are several suction nozzles, each of which is mounted on the flexible head body, one end of each suction nozzle is located in the inner cavity of the flexible head body, and the other end of each suction nozzle is connected to an air pump;

[0014] A camera, wherein the camera is disposed in the flexible head body;

[0015] A controller, wherein the camera and the air pump are electrically connected to the controller.

[0016] Preferably, the open arc ring is fixed to the flexible head body through a short connecting plate, and the short connecting plate is fixedly connected to the open arc ring and the flexible head body respectively through connecting rivets.

[0017] Preferably, a stud is fixed at both ends of each open arc ring, the lower end of the stud is fixed on the open arc ring, the upper end of the stud is connected to a nut, a guide arc ring is provided on the adjacent end of the two open arc rings, an arc groove is provided on the guide arc ring, the stud passes through the arc groove, and the nut is located at the upper end of the arc groove.

[0018] Preferably, the guide arc ring is connected to the flexible head carcass via a long connecting plate, and both ends of the long connecting plate are fixedly connected to the guide arc ring and the flexible head carcass respectively via connecting rivets.

[0019] Preferably, the suction nozzle includes a suction cup, a buffer airbag, a suction cup mounting tube and a suction tube interface which are connected in sequence, the suction cup and the buffer airbag are located in the inner cavity of the flexible head body, the suction cup mounting tube passes through the side wall of the flexible head body, and the suction tube interface is connected to the air pump through an air pipe.

[0020] Preferably, a camera mounting seat is fixed inside the flexible head body, and the camera is fixed on the camera mounting seat.

[0021] Preferably, the flexible head body is made of silicone or shape memory alloy.

[0022] The invention discloses a picking method of an expandable apple picking device, comprising the following steps:

[0023] S1. Positioning and identifying apples: using the controller to detect the apples in the pictures captured by the camera, and using the controller to calculate the actual three-dimensional coordinates, diameter size and center of mass coordinates of the target apples;

[0024] S2, judgment of single fruit and clustered fruit, after obtaining the spatial position and information of the target apple, calculate the overlapping area of ​​any target apple and its surrounding apple detection frame. If the overlapping area is greater than a fixed threshold, it is considered that the overlapping apples are clustered fruits, otherwise, they are single fruits;

[0025] When the fruits are clustered, all the clustered fruits are regarded as a big apple, and the three-dimensional coordinates of the big apple are obtained according to step S1;

[0026] S3, the expansion of the caliber of the grabbing end, according to the judgment of the detected apple fruit, the diameter of the flexible head body is adjusted to the diameter of the corresponding fruit;

[0027] S4, approaching the target fruit, after the flexible head body diameter is adapted to the picked fruit, the controller controls the movement of the robotic arm to drive the entire device to slowly approach the target fruit according to the calculated three-dimensional coordinates of the fruit, and stops when the center of mass of the target fruit is located near the suction nozzle;

[0028] S5, narrowing the diameter of the gripping end, after the target fruit enters the inner space of the flexible head body, shrinking the diameter of the flexible head body so that the suction nozzle is attached to the fruit without applying suction;

[0029] S6, sucking and picking of apples. After the diameter of the gripping end is reduced and the suction cup is attached, the controller controls the air pump installed on the robotic arm to provide suction for the suction nozzle. After sucking, the controller controls the rotation of the robotic arm to drive the device to rotate to achieve the twisting and falling of the fruit; then move the robotic arm to the fruit receiving position, turn off the suction provided by the air pump and expand the diameter of the gripping end again to achieve the falling of the apple from the suction nozzle to the fruit collection box.

[0030] Compared with the prior art, the present invention has achieved the following technical effects:

[0031] The flexible head with variable diameter designed in the present invention enables a single device to have the function of picking both single and multiple fruits, thus improving applicability and effectively avoiding the problems of the existing pickers being unable to pick multiple fruits or being unable to enter the device, damaging adjacent apples, and apples falling when picking multiple fruits as single fruits one by one, thus improving the efficiency and benefits of picking;

[0032] Furthermore, the staggered distribution of the upper and lower layers of the suction nozzle can effectively adapt to the situation where multiple fruits are staggered and distributed at different heights, improving the utilization efficiency of the suction nozzle and the reliability of multiple fruit suction, and to a great extent avoiding the phenomenon that a certain fruit in the multiple fruits has no nozzle to suck or cannot be sucked. In addition, for a single fruit, this distribution pattern can suck a single fruit from different directions and heights, which also improves the robustness of suction when picking a single fruit;

[0033] Furthermore, the initial attachment process of the suction cup to the fruit can be fine-tuned and adapted to a better suction position through slight displacement caused by slight squeezing of the fruit with the suction cup, avoiding internal damage caused by a poor suction position and the need for greater suction force when the suction cup directly sucks the fruit, or the phenomenon of falling off in the middle due to a poor suction position, thereby improving the success rate and lossless rate of suction. In addition, the cushioning airbag behind the suction cup can effectively avoid fruit squeezing damage caused by hard contact between the suction cup and the fruit, and improve the lossless rate of picking.

[0034] Furthermore, the action of expanding before picking and then shrinking the wrapping also improves the success rate of the picking process. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 This is a schematic diagram of the structure of an expandable apple picking device according to Example 1;

[0037] Figure 2 It is a top view of the expandable apple picking device of Example 1;

[0038] Figure 3 It is a side view of the expandable apple picking device of Example 1;

[0039] Figure 4 This is a schematic diagram of the structure of the suction nozzle in the expandable apple picking device in Example 1;

[0040] Figure 5 It is a schematic diagram of the structure of the arc groove and the open arc ring in the expandable apple picking device of Example 1;

[0041] Figure 6 This is a flow chart of a picking method of an expandable apple picking device according to Embodiment 2;

[0042] In the figure: 1-short connecting plate, 2-connecting rivet, 3-suction cup, 4-camera, 5-stud, 6-nut, 7-suction cup mounting tube, 8-guide arc ring, 9-support tube, 10-displacement ring, 11-open push rod, 12-mounting plate, 13-flexible head body, 14-camera mounting seat, 15-buffer airbag, 16-long connecting plate, 17-open arc ring, 18-suction nozzle, 19-suction tube interface. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The purpose of the present invention is to provide an expandable apple picking device and a picking method thereof, which are used to solve the technical problems existing in the above-mentioned prior art. A flexible head body and a suction nozzle with adaptive diameter adjustment are used to grab single fruits and clustered fruits, which greatly improves the practicality and picking efficiency of the grabbing mechanism. The entire process does not require human intervention and supervision, which is beneficial to the mechanization and intelligent development of the apple industry.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. Example

[0046] like Figure 1-Figure 5 As shown, this embodiment provides an expandable apple picking device, comprising:

[0047] Support tube 9, support tube 9 is a common support tube 9 structure, and the lower end of support tube 9 is used to connect the mechanical arm of the picking robot;

[0048] A flexible head body 13, the flexible head body 13 is made of a flexible material, the lower end of the flexible head body 13 is fixed to the upper end of the support tube 9, and the flexible head body 13 and the support tube 9 are fixedly connected via a mounting plate 12;

[0049] Open arc ring 17, there are two open arc rings 17, the two open arc rings 17 are arranged oppositely at the upper end of the flexible head body 13, and the openings of the two open arc rings 17 are arranged oppositely;

[0050] The displacement ring 10 is slidably connected to the outer wall of the support tube 9. Specifically, two slide rails are provided on the tube wall of the support tube 9. The displacement ring 10 is provided with two opposite pulleys, and the two pulleys are slidably connected on the two slide rails. The displacement ring 10 is connected to a linear drive device, and the linear drive device drives the displacement ring 10 to move up and down;

[0051] Open push rod 11, there are two open push rods 11, the open push rod 11 is a C-shaped rod structure, the upper ends of the two open push rods 11 are respectively hinged to the two open arc rings 17, and the lower ends of the two open push rods 11 are hinged to the two ends of the displacement ring 10. In order to achieve the hinge, the open arc ring 17 and the displacement ring 10 are provided with a rotating round rod, and the upper and lower ends of the open push rod 11 are respectively provided with a rotating round hole, each rotating round rod passes through a corresponding rotating round hole and can rotate relatively, so that the open push rod 11 can achieve its hinge with the open arc ring 17 and the displacement ring 10;

[0052] A suction nozzle 18, which is a plurality of suction nozzles 18, is installed on the flexible head body 13, one end of the suction nozzle 18 is located in the inner cavity of the flexible head body 13, and the other end of the suction nozzle 18 is connected to an air pump. Specifically, six suction nozzles 18 are provided, and the six suction nozzles 18 are staggered in upper and lower layers;

[0053] Camera 4, which is disposed in the flexible head body 13;

[0054] The controller, the camera 4 and the air pump are all electrically connected to the controller, and the controller is a remote control terminal, including Arduino or Raspberry Pi.

[0055] In actual use, when it is necessary to grab an apple, the opening of the flexible head 13 needs to be enlarged first. The specific operation method is to use a controller to control the linear drive device to drive the displacement ring 10 to move upward along the slide rails on both sides of the support tube 9, thereby driving the lower end of the opening push rod 11 to rotate downward along the hinge with the displacement ring 10. The downward rotation of the lower end of the opening push rod 11 will generate an upward pulling force on its upper end, and this pulling force will pull the opening arc ring 17 to expand under the conversion of the hinge form between the opening push rod 11 and the opening arc ring 17. Since the opening arc ring 17 is connected to the top of the flexible head 13, and the flexible head 13 is a flexible material, it can be deformed under the action of a certain external force. Therefore, when the opening arc ring 17 expands, the opening and the whole of the flexible head 13 will also expand accordingly, thereby realizing the adjustment of the diameter of the flexible head 13.

[0056] When the diameter of the flexible head body 13 becomes larger, the mechanical arm is controlled to make the entire expandable apple picking device close to the target apple, and the center of mass of the target fruit is located between the plane where the centers of the upper three suction nozzles 18 are located and the plane where the centers of the lower three suction nozzles 18 are located.

[0057] Then, the opening of the flexible head 13 needs to be reduced. The specific operation method is to use a controller to control the linear drive motor to drive the displacement ring 10 to move downward along the slide rails on both sides of the support tube 9, thereby driving the lower end of the opening push rod 11 to rotate upward along the hinge between it and the displacement ring 10. Since the upward rotation of the lower end of the opening push rod 11 will generate a downward pulling force on its upper end, and this pulling force will pull the opening arc ring 17 to perform a contraction movement under the conversion of the hinge form between the opening push rod 11 and the opening arc ring 17. Since the opening arc ring 17 is integrated with the flexible head 13, when the opening arc ring 17 performs a contraction movement, the diameter of the flexible head 13 will be reduced accordingly, and the suction nozzle 18 is fixedly connected to the flexible head 13, so the suction cup 3 of the suction nozzle 18 will slowly approach the fruit under the continuous contraction of the flexible head 13, and finally be initially adsorbed on the fruit.

[0058] After the narrowing of the gripping end aperture and the initial attachment of the suction nozzle 18 are completed, the controller controls the air pump to provide suction to the suction nozzle 18 to improve the robustness of apple suction. After suction, the controller controls the mechanical arm to rotate to drive the device to rotate to achieve the twisting and falling of the fruit. Then move the mechanical arm to the fruit receiving position, turn off the suction provided by the air pump and expand the end aperture again to achieve the falling of the apple from the suction cup 3 to the fruit collection box.

[0059] In this embodiment, the open arc ring 17 is fixed to the flexible head body 13 through the short connecting plate 1, and the short connecting plate 1 is fixedly connected to the open arc ring 17 and the flexible head body 13 through the connecting rivets 2. Specifically, the upper end of the short connecting plate 1 is fixed to the open arc ring 17 through two connecting rivets 2, and the lower end of the short connecting plate 1 is fixed to the flexible head body 13 through two connecting rivets 2, so as to achieve relative fixation of the open arc ring 17 and the flexible head body 13.

[0060] In this embodiment, a stud 5 is fixed at both ends of each open arc ring 17, the lower end of the stud 5 is fixed on the open arc ring 17, and a nut 6 is threadedly connected to the upper end of the stud 5, the stud 5 is provided with an external thread, and the nut 6 is provided with an internal thread, so as to realize the screw connection between the two. A guide arc ring 8 is provided on the adjacent end of the two open arc rings 17, and the guide arc ring 8 is provided with an arc groove, the stud 5 passes through the arc groove, and the nut 6 is located at the upper end of the arc groove, so as to prevent the guide arc ring 8 from detaching from the stud 5. Two studs 5 are sleeved in each guide arc ring 8, and when the two open arc rings 17 are expanded, the two studs 5 in each guide arc ring 8 will move away from each other; when the two open arc rings 17 are contracted, the two studs 5 in each guide arc ring 8 will move closer to each other. The guide arc ring 8 can guide the stud 5, thereby indirectly guiding the open arc ring 17.

[0061] In this embodiment, the guide arc ring 8 is connected to the flexible head body 13 through a long connecting plate 16. The size of the long connecting plate 16 is larger than that of the short connecting plate 1. The two ends of the long connecting plate 16 are respectively fixedly connected to the guide arc ring 8 and the flexible head body 13 through connecting rivets 2. Specifically, the upper end of the long connecting plate 16 is fixedly connected to the inner wall of the guide arc ring 8 through two connecting rivets 2, and the lower end of the long connecting plate 16 is fixedly connected to the inner wall of the flexible head body 13 through two connecting rivets 2.

[0062] In this embodiment, the suction nozzle 18 includes a suction cup 3, a buffer air bag 15, a suction cup mounting tube 7 and a suction tube interface 19 which are connected in sequence. The suction cup 3 and the buffer air bag 15 are located in the inner cavity of the flexible head body 13. The suction cup 3 is used to adsorb the fruit, and the buffer air bag 15 is used for buffering and reducing damage during initial adsorption. The suction cup mounting tube 7 passes through the side wall of the flexible head body 13, and the suction tube interface 19 is connected to the air pump through the air pipe. Of course, the air pump can also be replaced by a vacuum fan as long as it can provide negative pressure suction.

[0063] In this embodiment, a camera mounting seat 14 is fixed inside the flexible head body 13, and the camera 4 is fixed on the camera mounting seat 14. The camera 4 is installed at the top of the support tube 9, that is, the center of the flexible head body 13 through the camera 4 mounting base.

[0064] In this embodiment, the material of the flexible head body 13 is silicone or shape memory alloy. Of course, those skilled in the art may also use other flexible materials.

[0065] In this embodiment, the linear drive device is a dual-axis motor, each pulley includes two wheels, and the two output shafts of the dual-axis motor are respectively connected to the two wheels to drive the pulley to rotate. When the pulley moves up and down along the slide rail, the dual-axis motor will also move up and down. In addition, the dual-axis motor is also electrically connected to the controller to achieve remote control of the controller. Example

[0066] like Figure 6 As shown, this embodiment provides a picking method of an expandable apple picking device according to Embodiment 1, comprising the following steps:

[0067] S1. Apple’s positioning and identification:

[0068] Arduino or Raspberry Pi (i.e., controller) is used to call a trained deep learning target detection algorithm (e.g., YOLOv7 network) to detect the apple in the picture captured by the camera 4 in the device; the actual three-dimensional coordinates, diameter size, and center of mass coordinates of the target apple are calculated based on the position information of the rectangular detection frame (the coordinates of the left vertex of the rectangular frame and the length and width) and the actual distance represented by one pixel.

[0069] S2. Determination of single fruit and clustered fruit:

[0070] After obtaining the spatial position and information of the target apple, the overlapping area between any target apple and its surrounding apple detection frame is calculated. If the overlapping area is greater than a fixed threshold, the overlapping apples are considered to be clustered fruits. Otherwise, they are single fruits.

[0071] When it is a cluster of fruits, all clustered fruits are regarded as a big apple, and the detection frame of the big apple is the circumscribed rectangle of all cluster member detection frames, whose diameter is the length or width of the circumscribed rectangle, and the three-dimensional coordinates of the big apple are obtained according to step S1.

[0072] S3. Expansion of the grabbing end aperture:

[0073] According to the judgment of the apple fruit type (single fruit or clustered fruit) detected, the diameter of the flexible head body 13 is adjusted to the diameter of the corresponding fruit type to complete the adaptation of a single device to different fruit types. The specific process is as follows: Use Arduino (i.e., controller) to control the forward rotation of the dual-axis motor installed inside the support tube 9 to drive the displacement ring 10 to move upward along the slide rails embedded on both sides of the support tube 9, thereby driving the lower end of the opening push rod 11 to rotate downward along the hinge between it and the displacement ring 10; since the downward rotation of the lower end of the opening push rod 11 will affect the upper The end generates an upward pulling force, and this pulling force will pull the open arc ring 17 to expand along the arc groove under the conversion of the hinged form of the open push rod 11 and the open arc ring 17; because the open arc ring 17 is connected to the top of the flexible head body 13 through the short connecting plate 1 and the connecting rivet, and the flexible head body 13 is a flexible material, it can be deformed under the action of a certain external force. Therefore, when the open arc ring 17 expands along the arc groove, the opening and the whole of the flexible head body 13 will also expand accordingly, thereby realizing the adjustment of the diameter of the flexible head body 13. The diameter of the flexible head body 13 is determined by the rise of the displacement ring 10 controlled by Arduino. Because in the actual picking process, the fruit often vibrates under the action of the wind, causing a certain position offset, so the diameter of the flexible head body 13 is usually larger than the diameter of the fruit, so as to leave a certain margin.

[0074] S4. Approach the target fruit:

[0075] After the diameter of the flexible head body 13 is adapted to the picked fruits, Arduino (i.e., controller) is used to control the movement of the robotic arm according to the calculated three-dimensional coordinates of the fruit to drive the entire device to slowly approach the target fruit, and stop when the center of mass of the target fruit is located near the suction nozzle 18. The exact position is when the center of mass of the target fruit is between the plane where the centers of the upper three suction cups 3 are located and the plane where the centers of the lower three suction cups 3 are located.

[0076] S5. Reduction of the diameter of the gripping end:

[0077] After the target fruit enters the internal space of the flexible head barrel 13, the diameter of the flexible head barrel 13 is slightly contracted so that the suction cup 3 can initially and reliably adhere to the fruit without applying suction. The specific process is as follows: Use Arduino (controller) to control the reversal of the dual-axis motor installed inside the support tube 9 to drive the displacement ring 10 to move downward along the slide rails embedded on both sides of the support tube 9, thereby driving the lower end of the opening push rod 11 to rotate upward along the hinge between it and the displacement ring 10; the upward rotation of the lower end of the opening push rod 11 will produce a A downward pulling force, and this pulling force will pull the open arc ring 17 to contract along the arc groove under the conversion of the hinged form of the opening push rod 11 and the open arc ring 17; since the open arc ring 17 and the flexible head barrel 13 are integrated, when the open arc ring 17 contracts along the arc groove, the diameter of the flexible head barrel 13 will shrink accordingly, and the suction nozzle 18 is fixedly connected to the flexible head barrel 13, so the suction cup 3 of the suction nozzle 18 will slowly approach the fruit under the continuous contraction of the flexible head barrel 13, and finally be initially adsorbed on the fruit.

[0078] In order to avoid the continuous contraction of the flexible head body 13 and the squeezing damage to the apple caused by the hard contact between the suction cup 3 and the fruit, the buffer air bag 15 behind the suction cup 3 is used to buffer the force of the contraction process, and when the buffer air bag 15 is reduced to a fixed length (for example, 1 / 3), the contraction of the flexible head body 13 is stopped, that is, Arduino controls the dual-axis motor to stop reversing.

[0079] S6. Suction and picking of apples:

[0080] After the narrowing of the gripping end aperture and the initial attachment of the suction cup 3 are completed, the air pump or vacuum fan installed on the robotic arm is controlled by Arduino (controller) to provide suction for the suction cup 3, so as to improve the robustness of apple suction; after suction, the robotic arm is controlled to rotate by Arduino to drive the device to rotate to achieve the twisting and falling of the fruit; then the robotic arm is moved to the fruit receiving position, the suction provided by the air pump or vacuum fan is turned off, and the gripping end aperture is expanded again to achieve the falling of the apple from the suction cup 3 to the fruit collection box.

[0081] The present specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An expandable apple picking device, characterized in that: include: A support tube, the lower end of which is used to connect to the mechanical arm of the picking robot; A flexible head, the lower end of which is fixed to the upper end of the support tube; An open arc ring, wherein there are two open arc rings, and the two open arc rings are arranged oppositely at the upper end of the flexible head body; A displacement ring, wherein the displacement ring is slidably connected to the outer wall of the support tube, and the displacement ring is connected to a linear drive device, and the linear drive device drives the displacement ring to move up and down; An opening push rod, wherein there are two opening push rods, the upper ends of the two opening push rods are respectively hinged to the two opening arc rings, and the lower ends of the two opening push rods are hinged to the two ends of the displacement ring; A suction nozzle, wherein there are several suction nozzles, each of which is mounted on the flexible head body, one end of each suction nozzle is located in the inner cavity of the flexible head body, and the other end of each suction nozzle is connected to an air pump; A camera, wherein the camera is disposed in the flexible head body; A controller, the camera and the air pump are both electrically connected to the controller; A stud is fixed at both ends of each open arc ring, the lower end of the stud is fixed on the open arc ring, the upper end of the stud is connected with a nut, a guide arc ring is provided on the adjacent ends of the two open arc rings, the guide arc ring is provided with an arc groove, the stud passes through the arc groove, and the nut is located at the upper end of the arc groove; The guide arc ring is connected to the flexible head body through a long connecting plate, and the two ends of the long connecting plate are respectively fixedly connected to the guide arc ring and the flexible head body through connecting rivets; The suction nozzle includes a suction cup, a buffer air bag, a suction cup mounting tube and a suction tube interface which are connected in sequence. The suction cup and the buffer air bag are located in the inner cavity of the flexible head body, the suction cup mounting tube passes through the side wall of the flexible head body, and the suction tube interface is connected to the air pump through an air pipe.

2. The expandable apple picking device according to claim 1, characterized in that: The open arc ring is fixed to the flexible head body through a short connecting plate, and the short connecting plate is fixedly connected to the open arc ring and the flexible head body respectively through connecting rivets.

3. The expandable apple picking device according to claim 1, characterized in that: A camera mounting seat is fixed inside the flexible head body, and the camera is fixed on the camera mounting seat.

4. The expandable apple picking device according to claim 1, characterized in that: The material of the flexible head body is silicone or shape memory alloy.

5. A picking method based on the expandable apple picking device according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Positioning and identifying apples: using the controller to detect the apples in the pictures captured by the camera, and using the controller to calculate the actual three-dimensional coordinates, diameter size and center of mass coordinates of the target apples; S2, judgment of single fruit and clustered fruit, after obtaining the spatial position and information of the target apple, calculate the overlapping area of ​​any target apple and its surrounding apple detection frame. If the overlapping area is greater than a fixed threshold, it is considered that the overlapping apples are clustered fruits, otherwise, they are single fruits; When the fruits are clustered, all the clustered fruits are regarded as a big apple, and the three-dimensional coordinates of the big apple are obtained according to step S1; S3, the expansion of the caliber of the grabbing end, according to the judgment of the detected apple fruit, the diameter of the flexible head body is adjusted to the diameter of the corresponding fruit; S4, approaching the target fruit, after the flexible head body diameter is adapted to the picked fruit, the controller controls the movement of the robotic arm to drive the entire device to slowly approach the target fruit according to the calculated three-dimensional coordinates of the fruit, and stops when the center of mass of the target fruit is located near the suction nozzle; S5, narrowing the diameter of the gripping end, after the target fruit enters the inner space of the flexible head body, shrinking the diameter of the flexible head body so that the suction nozzle is attached to the fruit without applying suction; S6, sucking and picking of apples. After the diameter of the gripping end is reduced and the suction cup is attached, the controller controls the air pump installed on the robotic arm to provide suction for the suction nozzle. After sucking, the controller controls the rotation of the robotic arm to drive the device to rotate to achieve the twisting and falling of the fruit; then move the robotic arm to the fruit receiving position, turn off the suction provided by the air pump and expand the diameter of the gripping end again to achieve the falling of the apple from the suction nozzle to the fruit collection box.

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