A finger drum air suction and release type proximity trigger variable structure flexible picking manipulator and a control method thereof

Abstract

The present application relates to the technical field of agricultural fruit automatic picking robot, in particular to a kind of finger disc suction and air release type proximity trigger variable structure flexible picking manipulator and control method thereof, the finger disc suction and air release type proximity trigger variable structure flexible picking manipulator, including support, one end of the support is connected with mechanical arm by gripping drive system, image acquisition equipment is installed on the mechanical arm, variable structure mechanism is installed in the middle of the support and is connected with finger disc suction and air release type gripping device by variable structure mechanism, proximity trigger system is installed at the other end of the support;The proximity trigger system and image acquisition equipment are connected with variable structure mechanism, finger disc suction and air release type gripping device by gripping drive system to realize the adaptive automatic picking of fruit;The beneficial effects of the present application are that the present application realizes finger disc suction and air release type gripping and passive gripping force control, realizes proximity type gripping trigger, and changes gripping structure for different shape fruits to realize effective gripping, improves the accuracy of fruit picking, realizes automatic picking, easy to operate, and strong popularization.

Description

Technical Field

[0001] This invention belongs to the field of automated agricultural fruit harvesting robot technology, specifically relating to a finger-disc suction and degassing type proximity trigger variable structure flexible harvesting manipulator and its control method. Technical Background

[0002] Flexible robotic arms, as a means of achieving low-damage and non-damage fruit harvesting in the agricultural field, have developed rapidly with the rise of intelligent harvesting robots. However, the existing technology system still has significant limitations. First, the grasping action of current pneumatic flexible robotic arms is driven by a centralized air source, which is bulky, costly, and requires a high-precision air pressure and airflow control system. Second, the grasping behavior and force are entirely controlled actively, often requiring precise force feedback to achieve low-damage grasping, further increasing control costs. Third, current mainstream pneumatic harvesting devices generally adopt a homogeneous structure, and the actuator lacks active deformation capability, only able to achieve grasping operations for a single variety through preset shapes, and unable to achieve non-damage harvesting for fruits of various shapes.

[0003] Chinese invention patent "A picking robot and its picking method applicable to picking various fruits" (CN112840862B) can pneumatically pick various fruits of different sizes by adjusting the gripping range of its soft fingers. However, it still requires an external air compressor for drive. After picking begins, the air pressure inside the soft fingers cannot be automatically adjusted, making it difficult to achieve force-adaptive, damage-free picking of different fruits. Furthermore, due to its simple and non-deformable structure, it cannot accurately grasp complex-shaped fruits and vegetables such as cylindrical and square fruits and vegetables, resulting in poor versatility. Chinese invention patent "A fruit and vegetable picking actuator based on flexible gripping and clamping and shearing integration and its picking method" (CN110432000B) can pick fruits and vegetables of different shapes by changing its structure. However, its soft fingers can only bend and deform according to the preset air pressure. It adopts an active control gripping method and cannot adaptively adjust the clamping force according to the specific size of the target fruit or vegetable.

[0004] A search of existing technologies reveals that there is currently no flexible harvesting robot that combines finger-disc suction / degassing, proximity triggering, and adaptive structural design. To meet the demands of modern intelligent harvesting technology, this invention proposes a finger-disc suction / degassing proximity triggering flexible harvesting robot and its control method. This will enable automated, non-destructive harvesting of various fruits, further promoting the development of harvesting robot technology in my country. Summary of the Invention

[0005] This invention addresses the current lack of universal, low-damage end effectors in my country's intelligent agricultural harvesting field by providing a finger-disc suction and degassing type proximity-triggered variable structure flexible harvesting robot and its control method. It enables finger-disc suction and degassing gripping and passive gripping force control, achieves proximity-triggered gripping, and changes the gripping structure to achieve effective gripping for fruits of different shapes.

[0006] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is: a finger-disc suction and release type proximity trigger variable structure flexible picking robot, including a bracket connected to a robotic arm equipped with an image acquisition device, a gripping drive system installed at one end of the bracket, a variable structure mechanism installed in the middle of the bracket and connected to a finger-disc suction and release type gripping device through the variable structure mechanism, and a proximity trigger system installed at the other end of the bracket; the proximity trigger system and the image acquisition device are communicatively connected to the variable structure mechanism and the finger-disc suction and release type gripping device through the gripping drive system to achieve adaptive automated picking of fruits.

[0007] The bracket includes a fixed base, a connecting base, and a hardware fixing plate. The gripping drive system is installed at one end of the fixed base, and the other end of the fixed base is connected to the hardware fixing plate through the connecting base. The variable structure mechanism is installed on the connecting base, and the proximity triggering system is installed on the hardware fixing plate.

[0008] One end of the fixed base is open. The connecting base includes a connecting rod fixing plate, a support column, and a mounting plate. The connecting rod fixing plate is installed at the open end of the fixed base. The connecting rod fixing plate is connected to the mounting plate through multiple support columns. The variable structure mechanism is installed between the mounting plate and the connecting rod fixing plate. A hardware fixing plate is installed on the side of the mounting plate away from the support column.

[0009] The variable structure mechanism includes a servo motor mounted on the mounting plate and a transmission mechanism mounted on the connecting rod fixing plate. The servo motor is connected to the gripping drive system through the transmission mechanism.

[0010] The transmission mechanism includes a double-blade transmission rod, a slider, a linkage mechanism, a transmission shaft, and a transmission block. The double-blade transmission rod is installed on the drive end of the servo motor. Sliders are slidably connected to both ends of the double-blade transmission rod. Each slider is connected to a corresponding transmission shaft through multiple sets of linkage mechanisms. Multiple transmission shafts are connected to the finger disk suction and release gripping device through corresponding transmission blocks.

[0011] The middle part of the double-blade transmission rod is fixedly connected to the drive end of the servo motor. Both ends of the double-blade transmission rod are respectively provided with arc-shaped sliding grooves arranged in a centrally symmetrical manner. A connecting post is slidably connected in each arc-shaped sliding groove and connected to the slider through the connecting post. The middle part of the connecting rod fixing plate is provided with a strip-shaped sliding groove that is slidably connected to the two sliders. The connecting rod mechanism includes an active rod that is rotatably connected to the slider and a driven rod that is rotatably connected to the active rod. The driven rod is fixedly connected to the corresponding transmission shaft. The connecting rod mechanism and the transmission shaft are respectively installed on both sides of the connecting rod fixing plate.

[0012] The finger-plate suction and release gripping device includes finger fixing components, soft fingers, micro air pumps and air tubes. Multiple finger fixing components are provided and are respectively installed on corresponding transmission blocks. Each finger fixing component is connected to a soft finger. The soft finger is connected to the micro air pump through an air tube to realize the adaptive gripping of the soft finger on the fruit.

[0013] The finger fixing component includes a constraint base fixed on the transmission block and a clamping block that is snapped inward thereon. The soft finger is nested and fixed in the clamping space between the constraint base and the clamping block.

[0014] The soft finger includes a strain layer, a limiting layer, and flexible suction cups. The strain layer and the limiting layer are fixedly connected. The strain layer is located on the side away from the fruit, and the limiting layer is attached and fixedly connected to the side of the strain layer closer to the fruit. On the side of the strain layer away from the limiting layer, multiple flat arc-shaped structures are spaced apart along its length. Multiple arc-shaped air channels are irregularly arranged inside the strain layer. The multiple arc-shaped air channels are connected to form a sealed air channel. One end of the sealed air channel is connected to one air port of the micro air pump through air pipe I. Multiple interconnected tubular air channels are arranged inside the limiting layer. Multiple flexible suction cups are installed on the side of the limiting layer away from the strain layer. The multiple flexible suction cups are connected to the corresponding tubular air channels. The multiple tubular air channels converge and are connected to another air port of the micro air pump through air pipe II.

[0015] The proximity triggering system includes a color sensor and a distance sensor mounted on the hardware mounting plate facing the fruit side;

[0016] The grasping drive system includes a motor driver, an embedded picking controller, and a power supply installed on the fixed base at the end away from the connecting base. The motor driver includes a motor driver I for driving the variable structure mechanism and a motor driver II for driving the finger disk suction and release grasping device. The proximity triggering system and the image acquisition device are communicatively connected to the motor driver and the robotic arm through the embedded picking controller.

[0017] The control method for the finger-disc suction and desorption type proximity trigger variable structure flexible harvesting robot includes the following steps:

[0018] 1) System initialization, calibrating the image acquisition device and robotic arm;

[0019] 2) The image acquisition device, driven by the robotic arm, acquires information about the fruit images within its field of view;

[0020] 3) The collected fruit images are uploaded to the grasping drive system, which controls the deformation of the variable structure mechanism according to the shape and size of the fruit;

[0021] 4) Determine the spatial coordinates of the fruit and the grasping posture;

[0022] 5) Plan the fruit picking route;

[0023] 6) Plan the proximity trigger for the finger-disc suction and release grasping action;

[0024] 7) The robotic arm drives the harvesting robot to grab the target fruit in sequence according to the methods in steps 4), 5), and 6) above;

[0025] 8) Determine whether the picking robot has picked up the target fruit. If it has not picked up the fruit, continue to execute the instructions sequentially from step 3). If the target fruit has been picked up, the robotic arm drives the picking robot to pick up the fruit by pulling and place the fruit in the storage area.

[0026] 9) Determine if all the fruits have been picked. If not, continue executing the instructions sequentially from step 3). If all the fruits have been picked, determine if a sufficient amount of fruits has been obtained. If a sufficient amount of fruits has not been obtained, continue executing the instructions sequentially from step 2). If a sufficient amount of fruits has been obtained, end the action and the robotic arm returns to its initial position.

[0027] Compared with existing technologies, the present invention has the following advantages:

[0028] 1) This invention provides a finger-disc suction and de-air type proximity trigger variable structure flexible picking robot. The end of the robot achieves adaptive grasping through the suction and de-air of the flexible finger disc, thereby realizing passive grasping force control and reducing damage to the fruit during the picking process.

[0029] 2) This invention designs a variable structure mechanism and a proximity triggering system to change the gripper structure for fruits of different shapes to achieve effective grasping, and achieves proximity-based grasping triggering by detecting color and target distance. It proposes a grasping control method that changes structure first and then approaches to trigger, which improves the accuracy of fruit picking.

[0030] 3) This invention achieves automated harvesting by designing an integrated grasping drive system that combines fruit recognition, positioning, variable grasping structure, proximity triggering, and finger-disc suction and degassing. It is highly automated, easy to operate, and has strong scalability. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the finger-disc suction and degassing type proximity trigger variable structure flexible picking robot of the present invention mounted on the robotic arm;

[0032] Figure 2 This is a schematic diagram of the overall structure of the finger-disc suction and degassing type proximity trigger variable structure flexible harvesting robot of the present invention;

[0033] Figure 3 This is a schematic diagram of the structure of the finger-disc suction and degassing type proximity trigger variable structure flexible picking robot of the present invention for grasping columnar fruits;

[0034] Figure 4 This is a schematic diagram of the structure of the finger-disc suction and degassing proximity-triggered flexible picking robot of the present invention for grasping spherical fruits;

[0035] Figure 5 This is a schematic diagram of the variable structure mechanism of the present invention;

[0036] Figure 6 This is a schematic diagram of the transmission mechanism in the variable structure mechanism of the present invention;

[0037] Figure 7 for Figure 5 Schematic diagram of the structure of the double-blade transmission rod;

[0038] Figure 8 This is an exploded view of the soft finger in the finger-plate suction and release gripping device of the present invention;

[0039] Figure 9 This is a full sectional view of the soft finger in the finger-plate suction and release grasping device of the present invention;

[0040] Figure 10 This is a schematic diagram of the installation structure of the micro air pump in the finger-disc suction and release gripping device of the present invention.

[0041] Figure 11 This is a schematic diagram of the installation structure of the proximity triggering system of the present invention;

[0042] Figure 12 This is a schematic diagram of the installation structure of the gripping drive system of the present invention;

[0043] Figure 13 This is a flowchart of the control method for the finger-disc suction and degassing type proximity trigger variable structure flexible picking robot of the present invention;

[0044] The markings in the above figures are as follows: 1. Bracket, 1-1. Fixed base, 1-2. Connecting base, 1-21. Linkage fixing plate, 1-211. Strip groove, 1-22. Support column, 1-23. Mounting plate, 1-3. Hardware fixing plate, 2. Grasping drive system, 2-1. Motor driver, 2-2. Embedded picking controller, 2-3. Power supply, 3. Robotic arm, 4. Image acquisition device, 5. Variable structure mechanism, 5-1. Servo motor, 5-2. Transmission mechanism, 5-21. Double-blade transmission rod, 5-211. Arc-shaped groove, 5-22. Slider, 5- 23. Linkage mechanism, 5-24. Drive shaft, 5-25. Drive block, 6. Finger disc suction and release gripping device, 6-1. Finger fixing component, 6-11. Constraint base, 6-12. Clamping block, 6-2. Soft finger, 6-21. Strain layer, 6-211. Flat arc-shaped structure, 6-212. Arc-shaped airway, 6-22. Restriction layer, 6-221. Tubular airway, 6-23. Flexible suction cup, 6-3. Miniature air pump, 6-4. Air tube I, 6-5. Air tube II, 7. Proximity triggering system, 7-1. Color sensor, 7-2. Distance sensor. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0046] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0047] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] The invention will now be further described with reference to the accompanying drawings. Figures 1-4As shown, this invention provides a finger-disc suction and release type proximity-triggered variable structure flexible harvesting robot. The harvesting robot includes a support 1 connected to a robotic arm 3 equipped with an image acquisition device 4. One end of the support 1 is equipped with a gripping drive system 2. The image acquisition device 4 can be configured as a depth camera to acquire images within the field of view to locate the fruit. A variable structure mechanism 5 is installed in the middle of the support 1 and connected to a finger-disc suction and release type gripping device 6. The deformation of the variable structure mechanism 5 drives the finger-disc suction and release type gripping device 6 to adaptively grip fruits of different shapes and sizes, achieving passive gripping force control and reducing damage to the fruit during harvesting. The other end of the support 1 is equipped with a proximity triggering system 7, which detects signals (such as fruit color and target distance) to trigger proximity gripping, thereby gripping and harvesting mature fruits and improving the accuracy of fruit harvesting. The proximity triggering system 7 and the image acquisition device 4 are connected to the variable structure mechanism 5 and the finger-disc suction and release gripping device 6 through the gripping drive system 2 to achieve adaptive automated fruit picking. The system is highly automated, easy to operate, and has strong scalability.

[0049] Specifically, such as Figure 2 As shown, the support 1 includes a fixed base 1-1, a connecting base 1-2, and a hardware fixing plate 1-3. A gripping drive system 2 is mounted on one end of the fixed base 1-1, and the gripping drive system 2 is connected to the robotic arm 3 via an end flange. This robotic arm 3 can be configured as a six-degree-of-freedom robotic arm. The other end of the fixed base 1-1 is connected to the hardware fixing plate 1-3 via the connecting base 1-2. A variable structure mechanism 5 is mounted on the connecting base 1-2, and a proximity triggering system 7 is mounted on the hardware fixing plate 1-3. This arrangement makes the installation of the proximity triggering system 7, the gripping drive system 2, and the variable structure mechanism 5 more rational, the structural layout more compact, reduces the overall size of the robotic arm, and makes operation more flexible.

[0050] The fixed base 1-1 has an open end and is designed as a box structure, providing installation space for other components and making the structural design more compact. The connecting base 1-2 includes a connecting rod fixing plate 1-21, a support column 1-22, and a mounting plate 1-23. The connecting rod fixing plate 1-21 is installed at the open end of the fixed base 1-1. The circumference of the connecting rod fixing plate 1-21 is connected to the mounting plate 1-23 through multiple support columns 1-22. An installation space is formed between the mounting plate 1-23 and the connecting rod fixing plate 1-2. The variable structure mechanism 5 is installed in this installation space. A hardware fixing plate 1-3 is installed on the side of the mounting plate 1-23 away from the support column 1-22. The hardware fixing plate 1-3 is connected to the variable structure mechanism 5 through a universal joint and is indirectly fixed to the connecting base. It is not affected by the movement of the variable structure mechanism 5 and is used to fix the proximity triggering system 7.

[0051] Specifically, such as Figure 2, Figures 5-7 As shown, the variable structure mechanism 5 includes a servo motor 5-1 mounted on the mounting plate 1-23 and a transmission mechanism 5-2 mounted on the connecting rod fixing plate 1-2. The servo motor 5-1 is connected to the finger disk suction and release type gripping device 6 through the transmission mechanism 5-2. The rotational motion of the drive shaft of the servo motor 5-1 is converted into the adaptive gripping change of the finger disk suction and release type gripping device 6 through the transmission mechanism 5-2, so as to realize the adaptive gripping of fruits of different shapes and sizes.

[0052] The transmission mechanism 5-2 includes a double-blade transmission rod 5-21, a slider 5-22, a linkage mechanism 5-23, a transmission shaft 5-24, and a transmission block 5-25. The double-blade transmission rod 5-21 is mounted on the drive end of the servo motor 5-1. Sliding sliders 5-22 are slidably connected to both ends of the double-blade transmission rod 5-21. Each slider 5-22 is connected to its corresponding transmission shaft 5-24 via multiple sets of linkage mechanisms 5-23. The figure shows two sets of linkage mechanisms 5-23. The two sets of linkage mechanisms 5-23 connected to each slider 5-22 are symmetrically arranged about the sliding direction of the slider 5-22. The linkage mechanisms 5-23 on the two sliders 5-22 are symmetrically arranged about an axis perpendicular to the sliding direction of the slider 5-22. Of course, more than two sets of linkage mechanisms 5-23 can be provided as needed. Each set of linkage mechanisms 5-23 is connected to one transmission shaft 5-24. Each transmission shaft 5-24 is connected to the finger-disc suction-release gripping device 6 via a transmission block 5-25. The middle part of the double-blade transmission rod 5-21 is fixedly connected to the drive end of the servo motor 5-1. Both ends of the double-blade transmission rod 5-21 are respectively provided with centrally symmetrical arc-shaped slide grooves 5-211. If the linkage mechanism 5-23 has 4 sets, two sets of centrally symmetrical arc-shaped slide grooves 5-211 are arranged on the double-blade transmission rod 5-21. Each arc-shaped slide groove 5-211 is slidably connected to a connecting post and connected to the slider 5-22 through the connecting post. The middle part of the connecting rod fixing plate 1-2 is provided with a strip-shaped slide groove 1-211 that slidably connects to the two sliders 5-22. The middle part of the connecting rod fixing plate 1-2 is provided with a rectangular hole. Strip plates are fixed to the inner and outer sides of the two opposite sides of the rectangular hole, forming a strip-shaped slide groove 1-211 between the two strip plates that slidably engages with the slider 5-22. The linkage mechanism 5-23 includes an active rod rotatably connected to the slider 5-22 and a driven rod rotatably connected to the active rod. The driven rod is fixedly connected to the corresponding transmission shaft 5-24. The linkage mechanism 5-23 and the transmission shaft 5-24 are respectively installed on both sides of the linkage fixing plate 1-2, and the transmission shaft 5-24 is vertically installed between the linkage fixing plate 1-2 and the mounting plate 1-23.During the rotation of the servo motor 5-1 drive shaft, which in turn drives the double-blade transmission rod 5-21, two sets of centrally symmetrical arc-shaped grooves 5-211 are arranged on the double-blade transmission rod 5-21. The two sliders 5-22 will slide relative to or towards each other along the strip grooves 1-211 under the constraint of the strip grooves 1-211. This will drive the linkage mechanism 5-23 on the two sliders 5-22 to rotate in opposite directions. This will drive the transmission shaft 5-24 on the side of the two sliders 5-22 to rotate in opposite directions around its central axis. Since the transmission block 5-25 is fixed at the connection between the transmission shaft 5-24 and the mounting plate 1-23, it will drive the transmission block 5-25, which is fixedly connected to the transmission shaft 5-24, to rotate. This is used for the final motion output of the variable structure mechanism 5. It can cause the finger-disc suction and release gripping device 6 connected to the transmission block 5-25 to expand outward or retract inward, so as to realize adaptive gripping of fruits of different shapes and sizes.

[0053] Specifically, such as Figure 2 , Figures 8-10 As shown, the finger-plate suction and release gripping device 6 includes a finger fixing component 6-1, a soft finger 6-2, a micro air pump 6-3, and an air tube. Multiple finger fixing components 6-1 are provided and are respectively installed on corresponding transmission blocks 5-25. Each finger fixing component 6-1 is connected to the soft finger 6-2. The soft finger 6-2 is connected to the micro air pump 6-3 through the air tube to realize the adaptive gripping of the soft finger on the fruit.

[0054] The finger fixing component 6-1 includes a constraint base 6-11 fixed on the transmission block 5-25 and a clamping block 6-12 that is snapped inward. The soft finger 6-2 is nested and fixed in the clamping space between the constraint base 6-11 and the clamping block 6-12, thus achieving reliable positioning and installation of the soft finger 6-2.

[0055] The soft finger 6-2 includes a strain layer 6-21, a confinement layer 6-22, and a flexible suction cup 6-23. The strain layer 6-21 and the confinement layer 6-22 are fixedly connected. The strain layer 6-21 is located on the side away from the fruit, and the confinement layer 6-22 is attached and fixedly connected to the side of the strain layer 6-21 closer to the fruit. Multiple flat, arc-shaped structures 6-211 are spaced apart along the length of the strain layer 6-21 on the side away from the confinement layer 6-22. The top of each flat, arc-shaped structure 6-211 has an angle, eliminating the upper part of the air cavity. Its overall height is only half that of a typical air cavity, yet it still meets the bending performance requirements of the soft finger 6-2 and saves on manufacturing materials. Multiple arc-shaped air channels 6-212 are irregularly arranged inside the strain layer 6-21. These multiple arc-shaped air channels 6-212 are interconnected to form a sealed air channel. One end of the sealed air channel is connected to an air port of a micro air pump 6-3 via an air pipe I 6-4. Multiple interconnected tubular air channels 6-221 are provided within the confinement layer 6-22. Multiple flexible suction cups 6-23 are installed on the side of the confinement layer 6-22 away from the strain layer 6-21, and these flexible suction cups 6-23 are connected to their corresponding tubular air channels 6-221. The multiple tubular air channels 6-221 converge and connect to another air port of the micro air pump 6-3 via air pipe II 6-5. Air pipe I 6-4 and air pipe II 6-5 are rubber hoses. The two ends of air pipe I 6-4 are connected to the air inlet (or outlet) of the micro air pump 6-3 and the air port of the confinement layer 6-22, respectively. The two ends of air pipe II 6-5 are connected to the air outlet (or inlet) of the micro air pump 6-3 and the air port of the strain layer 6-21, respectively, for gas transmission. In this invention, four soft fingers 6-2 are provided; however, more than four can be provided as needed to ensure the stability of fruit grasping.

[0056] Driven by the micro air pump 6-3, the flexible suction cup 6-23 on the confinement layer 6-22 draws air from the outside. Through the air tube I 6-4, the air enters the air inlet of the micro air pump 6-3 and exits from the air outlet. It then enters the sealed air passage of the strain layer 6-21 through the air tube II 6-5, thus causing the soft finger 6-2 to bend, and vice versa. The strain layer 6-21 is located on the back side of the soft finger 6-2, and the confinement layer 6-22 is located on the fingertip side. Inflating the strain layer 6-21 through its air inlet expands the arc-shaped air passage 6-212, allowing the soft finger 6-2 to bend towards the fingertip. Drawing air from the strain layer 6-21 compresses the arc-shaped air chamber, causing the soft finger 6-2 to bend towards the back side. Furthermore, the air passage of the flexible suction cup 6-23 is connected to the outside world, and the flexible suction cup 6-23 is connected to the air port of the restrictive layer 6-22 through the air passage, which is used to exchange gas with the outside world, thereby causing the strain layer 6-21 to bend. The flexible suction cup 6-23 can adaptively fit according to the type of fruit to be grasped. In this paper, a flat suction cup is selected. When the flexible suction cup 6-23 is fully attached to the surface of the fruit, the air pressure of the air chamber of the strain layer 6-21 of the soft finger 6-2 and the air chamber of the restrictive layer 6-22 are dynamically balanced by relying on the micro air pump 6-3. Thus, the flexible suction cup 6-23 can achieve adaptive suction and picking of different fruits by sucking and releasing air. In addition, the miniature air pump 6-3 is installed in the fixed base 1-1. The fixed base 1-1 is provided with multiple through slots around its circumference for the corresponding air pipes I 6-4 and II 6-5 to pass through. One or more miniature air pumps 6-3 can be installed. When one miniature air pump 6-3 is installed, the air inlet and air outlet of the miniature air pump 6-3 can be connected to the corresponding air pipes through multiple T-connectors. Of course, multiple miniature air pumps 6-3 can also be installed, and each miniature air pump 6-3 controls a soft finger 6-2.

[0057] Specifically, such as Figure 2 and Figure 11 As shown, the proximity triggering system 7 includes a color sensor 7-1 and a distance sensor 7-2 mounted on the hardware mounting plate 1-3 facing the fruit. The color sensor 7-1 is installed in a square slot in the hardware mounting plate 1-3, with its sensing head penetrating through and not exceeding the square slot and facing the fruit. It detects the ripeness of the fruit through color recognition and can provide supplemental lighting for the fruit within its field of view, facilitating harvesting. The laser distance sensor 7-2 is installed in a trapezoidal slot in the hardware mounting plate 1-3, with its lens penetrating through and not exceeding the trapezoidal slot and facing the fruit. It can measure the distance between the palm of the robotic arm and the fruit using the time-of-flight (TOF) method. When linked with the color sensor 7-1, it enables proximity-triggered harvesting of ripe fruit.

[0058] Specifically, such as Figure 2 and Figure 12As shown, the grasping drive system 2 includes a motor driver 2-1, an embedded picking controller 2-2, and a power supply 2-3 mounted on the fixed base 1-1 at the end away from the connecting base. The motor driver 2-1 includes motor driver 2-1Ⅰ for driving the servo motor 5-1 in the variable structure mechanism 5 and motor driver 2-1Ⅱ for driving the micro air pump 6-3 in the finger-disc suction and release grasping device 6. The embedded picking controller 2-2 can be implemented based on a single-chip microcomputer system, a microcontroller system, or an embedded computer system. The power supply 2-3 supplies power to the servo motor 5-1, the micro air pump 6-3, the depth camera, the color sensor 7-1, the distance sensor 7-2, and the embedded picking controller 2-2. The proximity triggering system 7 (color sensor 7-1, distance sensor 7-2) and the image acquisition device 4 are communicatively connected to the motor driver 2-1 and the robotic arm 3 through the embedded picking controller 2-2, enabling integrated control of different fruits identification, positioning, distance measurement, variable grasping structure, and picking.

[0059] The installation method of the picking robot of the present invention is as follows: the picking robot is installed on the robotic arm 3 with image acquisition device 4 through its end flange, and then the embedded picking controller 2-2 is connected to the color sensor 7-1, the distance sensor 7-2, the depth camera, the motor driver 2-1 and the robotic arm 3 through signal lines, thereby realizing the integrated control of fruit recognition, positioning, variable gripping structure, proximity triggering and finger disk suction and degassing gripping.

[0060] like Figure 13 As shown, the control method for the above-mentioned finger-disc suction and desorption type proximity trigger variable structure flexible picking robot includes the following steps:

[0061] 1) System initialization: Calibrate the image acquisition device 4 and the robotic arm 3. The depth camera on the robotic arm 3 is calibrated using the Zhang Zhengyou calibration method, and then the robotic arm 3 and the depth camera are calibrated using the hand-eye calibration method (eye outside the hand).

[0062] 2) The image acquisition device 4, driven by the robotic arm 3, acquires information about the fruit within its field of view. The embedded harvesting controller 2-2 controls the operation of the robotic arm 3, which moves the harvesting robot, enabling the image acquisition device 4 to clearly capture images of the fruit within its field of view. Then, the embedded harvesting controller 2-2 controls the image acquisition device 4 to acquire fruit image information. After acquisition, the fruit image information is uploaded to the embedded harvesting controller 2-2.

[0063] 3) The collected fruit images are uploaded to the grasping drive system 2. The grasping drive system 2 controls the deformation of the variable structure mechanism 5 according to the shape and size of the fruit. After receiving the image information uploaded by the image acquisition device 4, the embedded picking controller 2-2 calls the database information to identify and determine the specific shape of the target fruit. Then, the embedded picking controller 2-2 controls the motor driver 2-1Ⅰ to drive the servo motor 5-1 in the variable structure mechanism 5 to rotate at a certain angle. The variable structure mechanism 5 operates with the rotation of the servo motor 5-1, causing the finger fixing piece 6-1 at the end of the transmission block 5-25 installed in the variable structure mechanism 5 to drive the soft finger 6-2 to rotate at a certain angle, so that the bottom surface of the flexible suction cup 6-23 of the soft finger 6-2 is as parallel as possible to the surface contour of the target fruit, completing the grasping structure deformation operation.

[0064] 4) Determine the spatial coordinates of the fruit and the grasping pose. The embedded harvesting controller 2-2 begins detecting the fruit's characteristic features (perimeter, area, posture information, etc.) and position information.

[0065] The specific method is as follows: First, the fruit image information is preprocessed using a neural network algorithm to obtain image point cloud data;

[0066] Then, the detection box and mask information of the fruit are obtained through object detection and instance segmentation algorithms. The image is then segmented based on the detection box. The centroid of the fruit is detected by the centroid algorithm based on the mask information in the segmented area. The centroid matching algorithm is then introduced to classify the centroid of the fruit. The pose of the fruit is determined by the positional relationship and belonging relationship between the centroids, thus realizing the determination of the two-dimensional centroid coordinates and pose of the fruit.

[0067] Then, the embedded picking controller 2-2 calculates and transforms the two-dimensional centroid coordinates of the fruit in the image acquisition device 4 into three-dimensional centroid coordinates relative to the optical center of the image acquisition device 4 (depth camera), and then transforms them into world coordinates relative to the base of the robotic arm 3 to obtain the three-dimensional spatial position coordinates of the fruit.

[0068] a. The conversion process from two-dimensional centroid coordinates to three-dimensional centroid coordinates is as follows:

[0069] Assume the intrinsic parameter matrix of the image acquisition device (depth camera) is as follows:

[0070]

[0071] In the formula, f x f y Let c be the focal lengths of the depth camera in the x and y directions, respectively. x ,c y () represents the coordinates of the principal point of the image.

[0072] Transform the two-dimensional centroid coordinates (u, v) and the corresponding depth value d into three-dimensional centroid coordinates (X, v) in the depth camera coordinate system. c ,Y c Z c The conversion formula is as follows:

[0073]

[0074] Represented in matrix form as follows:

[0075]

[0076] b. The transformation process from 3D centroid coordinates to world coordinates is as follows:

[0077] Suppose that the pose of the depth camera to the robotic arm's base can be represented by a 4×4 homogeneous transformation matrix T:

[0078]

[0079] In the formula, R is a 3×3 rotation matrix, representing the rotation of the camera coordinate system relative to the robot arm base coordinate system; t is a 3×1 translation vector, representing the translation of the origin of the camera coordinate system relative to the origin of the robot arm base coordinate system.

[0080] The 3D centroid coordinates (X) in the depth camera coordinate system c ,Y c Z c Transform into world coordinates (X,Y,Z):

[0081]

[0082] After unfolding, we get:

[0083]

[0084] Finally, based on the determined fruit posture, the poses of robotic arm 3 and the picking robot hand when grasping the fruit are calculated, thus realizing the determination of the fruit grasping pose.

[0085] 5) Planning the fruit picking path. Based on the spatial position and grasping posture of the fruit determined by the above operations, the embedded picking controller 2-2 performs inverse kinematics solution according to the current coordinate values ​​of the robotic arm 3 and the picking robot and the grasping coordinate values, and interpolates to obtain the motion trajectory of the robotic arm 3 and the picking robot, thereby obtaining the fruit picking path and completing the target fruit picking path planning.

[0086] 6) Plan the proximity trigger finger disk suction and release grasping action. If the fruit is picked according to the planned path, when the embedded picking controller 2-2 controls the robotic arm 3 to drive the picking robotic hand to approach the target fruit in a straight and slow manner, the following operation is quickly performed. First, the embedded harvesting controller 2-2 controls the color sensor 7-1 to detect the color of the target fruit and uploads the detected color information to the embedded harvesting controller 2-2 for fruit ripeness detection. Second, if the target fruit is detected as unripe, the harvesting stops and the next fruit is harvested. If the target fruit is ripe, the embedded harvesting controller 2-2 controls the distance sensor 7-2 to determine the minimum distance between the palm of the harvesting robot and the target fruit. Finally, the distance information is uploaded to the embedded harvesting controller 2-2. When the appropriate harvesting distance is reached, the harvesting robot stops moving, and the embedded harvesting controller 2-2 controls the micro air pump 6-3 to suck and release air, causing the soft fingers 6-2 to bend. When the flexible suction cup 6-23 is fully attached to the surface of the target fruit, the micro air pump 6-3 is in an idle state, completing the proximity-triggered finger-disc suction and release gripping of the target fruit.

[0087] 7) The robotic arm 3 drives the picking robot to grab the target fruit in sequence according to steps 4), 5), and 6) above. Specifically, the embedded picking controller 2-2 automatically sends communication commands. After the overall control planning is completed, a fruit is randomly selected, and the embedded picking controller 2-2 sends the acquired information to each device in the form of operation commands according to the steps. Specifically, after receiving the operation command from the embedded picking controller 2-2, the variable structure mechanism 5 rotates at a fixed angle, deforming itself to the corresponding grasping structure of the fruit. Based on the operation command for the fruit, the following operations are performed: First, the embedded picking controller 2-2 controls the robotic arm 3 to move the picking robot along the picking path, bringing it to the front of the fruit's centroid, still some distance away. Then, the embedded picking controller 2-2 controls the end of the robotic arm 3 to rotate, moving the picking robot to the grasping position of the fruit. Second, the embedded picking controller 2-2 controls the robotic arm 3 to slowly approach the fruit, and after detecting that the fruit is ripe, slowly approaches until triggering the fruit's suction gripping action and then stops moving. Finally, as the grasping of the fruit stabilizes, the embedded picking controller 2-2 controls the robotic arm 3 to move the picking robot along the picking path to grasp the target fruit.

[0088] 8) Determine whether the picking robot has picked up the target fruit. If it has not picked up the fruit, continue to execute the instructions sequentially from step 3). If the target fruit has been picked up, the robotic arm 3 drives the picking robot to pick up the fruit by pulling and place the fruit in the storage area.

[0089] 9) Determine if all fruits have been picked. If not, continue executing instructions sequentially from step 3). If all fruits have been picked, determine if a sufficient quantity of fruits has been obtained. If not, continue executing instructions sequentially from step 2). If a sufficient quantity of fruits has been obtained, end the action and the robotic arm 3 returns to its initial position. The above determination methods can be implemented manually; or by pre-inputting the required quantity of fruits into the embedded picking controller 2-2, with the picking robot counting after each picking, and completing the picking work once the set quantity is reached; or by determining whether picking is complete based on whether there are still ripe fruits within the field of vision.

[0090] In summary, the finger-disc suction and degassing proximity-triggered variable structure flexible picking robot and its control method provided by this invention realize finger-disc suction and degassing gripping and passive gripping force control, achieve proximity-triggered gripping, and change the gripping structure for fruits of different shapes to achieve effective gripping, improve the accuracy of fruit picking, realize automated picking, are easy to operate, and have strong scalability.

[0091] The above description is merely an illustration of some principles of the present invention. This specification is not intended to limit the invention to the specific structure and scope of application shown. Therefore, all possible modifications and equivalents are within the scope of the patent application.

Claims

1. A flexible picking robot with a finger-disc suction and degassing type proximity triggering and variable structure, characterized in that: The system includes a support frame connected to a robotic arm equipped with an image acquisition device. One end of the support frame is equipped with a gripping drive system, the middle of the support frame is equipped with a variable structure mechanism and is connected to a finger-disc suction and release gripping device through the variable structure mechanism, and the other end of the support frame is equipped with a proximity trigger system. The proximity trigger system and the image acquisition device are connected to the variable structure mechanism and the finger-disc suction and release gripping device through the gripping drive system to achieve adaptive automated fruit picking. The bracket includes a fixed base, one end of which is equipped with a gripping drive system, and the other end of which is connected to a hardware mounting plate via a connecting base. A variable structure mechanism is installed on the connecting base, and a proximity triggering system is installed on the hardware mounting plate. The fixed base has an opening at one end, and the connecting base includes a connecting rod fixing plate installed at the opening end of the fixed base. The connecting rod fixing plate is connected to the mounting plate through multiple support columns. A variable structure mechanism is installed between the mounting plate and the connecting rod fixing plate. A hardware fixing plate is installed on the side of the mounting plate away from the support columns. The variable structure mechanism includes a servo motor mounted on a mounting plate and a transmission mechanism mounted on a connecting rod fixing plate. The servo motor is connected to the finger disc suction and release gripping device through the transmission mechanism. The transmission mechanism includes a double-blade transmission rod installed on the servo drive end. Sliders are slidably connected to both ends of the double-blade transmission rod. Each slider is connected to the corresponding transmission shaft through multiple sets of linkage mechanisms. Multiple transmission shafts are connected to the finger disk suction and release gripping device through corresponding transmission blocks. The middle part of the double-blade transmission rod is fixedly connected to the drive end of the servo motor. Both ends of the double-blade transmission rod are provided with arc-shaped slide grooves arranged in a centrally symmetrical manner. A connecting post is slidably connected in each arc-shaped slide groove and connected to the slider through the connecting post. The middle part of the connecting rod fixing plate is provided with a strip-shaped slide groove that is slidably connected to the two sliders. The connecting rod mechanism includes an active rod that is rotatably connected to the slider and a driven rod that is rotatably connected to the active rod. The driven rod is fixedly connected to the corresponding transmission shaft. The connecting rod mechanism and the transmission shaft are respectively installed on both sides of the connecting rod fixing plate. The finger-plate suction and release gripping device includes a finger fixing component installed on each transmission block and a soft finger connected to each finger fixing component. The soft finger is connected to a micro air pump through an air tube to achieve adaptive gripping of the fruit by the soft finger. The soft finger includes a strain layer and a confinement layer that are fixedly connected. The strain layer is located on the side away from the fruit, and the confinement layer is attached and fixedly connected to the strain layer on the side closer to the fruit. On the side of the strain layer away from the confinement layer, multiple flat arc-shaped structures are spaced apart along its length. Inside the strain layer, multiple arc-shaped air channels are arranged in a conformal manner. These multiple arc-shaped air channels are connected to form a sealed air channel. One end of the sealed air channel is connected to an air port of a micro air pump through air pipe I. Inside the confinement layer, multiple interconnected tubular air channels are arranged. On the side of the confinement layer away from the strain layer, multiple flexible suction cups are installed. These flexible suction cups are connected to corresponding tubular air channels. After the multiple tubular air channels converge, they are connected to another air port of the micro air pump through air pipe II.

2. The finger-disc suction and degassing type proximity-triggered variable structure flexible picking robot according to claim 1, characterized in that: The finger fixing component includes a constraint base fixed on the transmission block and a clamping block that is snapped inward thereon. The soft finger is nested and fixed in the clamping space between the constraint base and the clamping block.

3. The finger-disc suction and degassing type proximity-triggered variable structure flexible harvesting robot according to claim 1, characterized in that: The proximity triggering system includes a color sensor and a distance sensor mounted on the hardware mounting plate facing the fruit side; The grasping drive system includes a motor driver, an embedded picking controller, and a power supply installed on the fixed base at the end away from the connecting base. The motor driver includes a motor driver I for driving the variable structure mechanism and a motor driver II for driving the finger-disc suction and release grasping device. The proximity triggering system and the image acquisition device are communicatively connected to the motor driver and the robotic arm through the embedded picking controller, which can realize integrated control of different fruits identification, positioning, distance measurement, variable grasping structure, and picking.

4. A control method for a finger-disc suction and degassing type proximity-triggered variable structure flexible harvesting robot as described in any one of claims 1-3, characterized in that, Includes the following steps: 1) System initialization, calibrating the image acquisition device and robotic arm; 2) The image acquisition device, driven by the robotic arm, collects information on the fruit images within its field of view; 3) The collected fruit images are uploaded to the grasping drive system, which controls the deformation of the variable structure mechanism according to the shape and size of the fruit; 4) Determine the spatial coordinates of the fruit and the grasping posture; 5) Plan the fruit picking route; 6) Plan the proximity-triggered finger-disc suction and release grasping action; 7) The robotic arm drives the harvesting robot to grab the target fruit in sequence according to the methods in steps 4), 5), and 6) above; 8) Determine whether the picking robot has picked up the target fruit. If it has not picked up the fruit, continue to execute the instructions sequentially from step 3). If the target fruit has been picked up, the robotic arm drives the picking robot to pick up the fruit by pulling and place the fruit in the storage area. 9) Determine if all the fruits have been picked. If not, continue executing the instructions sequentially from step 3). If all the fruits have been picked, determine if a sufficient amount of fruits has been obtained. If a sufficient amount of fruits has not been obtained, continue executing the instructions sequentially from step 2). If a sufficient amount of fruits has been obtained, end the action and the robotic arm returns to its initial position.

Images