An automated palletizing method and palletizing apparatus for leather

Abstract

The application discloses an automatic stacking method and stacking equipment for leather and belongs to the technical field of leather processing and production. For a plurality of pieces of continuously stacked leather, an alternating stacking mode is adopted. For an odd-numbered piece of leather, a visual automatic positioning module calculates a grabbing point from the front part to the middle part of the leather, and when released, the negative pressure is disconnected in the order from the middle part to the front part, so that the piece of leather is stacked with the smooth surface upward. For an even-numbered piece of leather, the visual automatic positioning module calculates a grabbing point from the middle part to the rear part of the leather, and when released, the negative pressure is disconnected in the order from the middle part to the rear part, so that the piece of leather is stacked with the smooth surface downward. The smooth surfaces of two adjacent pieces of leather are in contact with each other. The application aims to solve the problems caused by long-term reliance on manual work in the leather carrying link in the traditional leather-making industry and realizes automatic, flexible and efficient operation.

Description

Technical Field

[0001] This invention relates to the field of leather processing and production technology, and in particular to an automated palletizing method and equipment for leather. Background Technology

[0002] In the leather processing and production process, stacking is a crucial step connecting material output with subsequent transfer and storage. The core requirement is to smoothly transfer and neatly stack the processed whole pieces of leather onto the leather transfer cart. Because leather is a typical irregular and flexible material, each piece of leather has significant natural differences in size, shape, and flatness, making standardization impossible. This has led to traditional leather stacking work relying entirely on manual labor: workers must manually grasp the leather, relying on experience to adjust the gripping position to ensure the leather is stable, before transferring it to the transfer cart for stacking.

[0003] Currently, in the traditional leather stacking process, workers first pull the leather out of the unloading area, then flip it over, and finally stack and spread it out on a transfer vehicle. However, the manual loading and manual flipping and stacking are traditional manual operations, which are labor-intensive and have low production efficiency. Because each piece of leather is relatively heavy, manual loading and flipping can easily cause the leather to slip and break during transportation.

[0004] In the prior art, such as the patent with publication number CN111470365A, a clamping automatic leather palletizing machine is disclosed, including a belt conveyor module, a clamping conveyor module, and a stacking module. In this invention, the leather is conveyed by a belt conveyor module that is tilted and has an adjustable tilt angle, thereby raising the height of the leather to facilitate the subsequent stacking of large quantities of leather. The clamping unit drive motor moves along the guide rail after the photoelectric sensor emits a signal, and at the same time, the clamping unit clamps one end of the leather. When the other end of the leather is removed from the belt conveyor module, another set of clamping units clamps the other end of the leather. In this way, the two sets of clamping units move synchronously under the drive of the clamping unit drive motor, moving the leather horizontally to the top of the stacking platform and stacking it on the stacking platform.

[0005] The clamping-type automatic leather palletizing machine has several shortcomings: First, the synchronous control scheme using dual independent drive clamping units is susceptible to interference from guide rail gaps, load fluctuations, and environmental disturbances, making it difficult to guarantee synchronization accuracy. Uneven tension can easily lead to leather stretching, deformation, or wrinkling. Furthermore, the photoelectric triggering clamping method is easily affected by irregular leather edges and reflections, resulting in a high misjudgment rate. Second, the equipment has poor material adaptability, only suitable for regular leather that can be clamped at both ends. It cannot accommodate irregularly shaped, oversized, or edge-damaged leather, making it difficult to meet the needs of multi-variety mixed-line production. Third, the inclined conveyor structure is prone to leather slippage and offset. The palletizing method is limited, lacks height adaptive adjustment, and increased stacking height differences can easily cause misalignment. Fourth, the electrical system is complex and prone to failure. The guide rails and clamping mechanisms are susceptible to dust contamination and wear, resulting in high maintenance costs and low cost-effectiveness in multi-variety, small-batch production scenarios.

[0006] For example, patent CN102492785A discloses an automatic leather stacking machine, which includes a lifting and fixing frame that can be raised and lowered in a vertical direction on the frame, and a movable conveyor belt that can move back and forth on the lifting and fixing frame; a feeding conveyor belt is installed on the frame, which is composed of two conveyor belts hinged together, the feeding end of the feeding conveyor belt is hinged to the frame, and the discharging end of the feeding conveyor belt is hinged to the lifting and fixing frame and is located between the front and rear stops of the movable conveyor belt.

[0007] The aforementioned automatic leather stacking machine has the following drawbacks: In terms of mechanical structure, the two-section articulated feeding conveyor belt is prone to wear, leading to a decrease in conveying accuracy. The load on the lifting mechanism continuously increases with the stacking height, making it prone to jamming and skewing, resulting in high maintenance costs. In terms of process, it lacks leather positioning, shaping, and anti-wrinkle design, making it difficult to ensure the stacking consistency of leathers of different specifications. Furthermore, it lacks a buffer adaptation mechanism, resulting in poor cycle flexibility. The automation level is low, with no sensor monitoring or intelligent adjustment functions, and insufficient ability to prevent smooth leather from falling off, making it prone to deviation and slippage. The equipment has weak versatility, is only suitable for a limited range of scenarios, and its linear layout occupies a large area with low space utilization, making it difficult to adapt to flexible production needs.

[0008] For example, patent CN111086917A discloses an automatic leather-gathering machine capable of high-speed stacking. It includes a support device with a fixed frame fixedly connected to its top. Two transport rollers are movably fitted inside the fixed frame. One end of each transport roller is fixedly connected to a first transmission mechanism. A transport motor is fixedly mounted on the side of the support device, and its output shaft is fixedly connected to the first transmission mechanism. The fixed frame, the first compression roller, and the second compression roller cooperate to transport the leather to the inside of a limiting cover via a belt. The limiting cover then transports the leather between the first and second compression rollers. A nut is rotated to adjust the distance between the first and second compression rollers, which flatten the leather for better stacking.

[0009] The aforementioned high-speed stacking automatic leather-gathering machine for leather preparation has the following defects: First, its leveling function is crude, relying solely on manual adjustment of the roller spacing to flatten the leather. This results in low precision, slow response, and a lack of flexible adaptation and active leveling design, making it unable to adapt to differences in leather thickness. High-speed production easily leads to damage or incomplete leveling. Second, its stacking stability is poor, lacking positioning, counting, and anti-folding mechanisms. The transmission speed is not synchronously controlled, making it prone to misalignment and congestion. Third, its structural reliability is insufficient. Exposed transmission components are susceptible to dust, and the lack of anti-loosening, tensioning, and buffering designs leads to a high failure rate. Fourth, its automation level is low, lacking sensor-based closed-loop control and data acquisition, relying on manual monitoring. This makes it unable to meet the needs of modern intelligent manufacturing and can only satisfy low-precision basic production requirements.

[0010] Based on the above, the present invention provides an automated palletizing method and palletizing equipment for leather. Summary of the Invention

[0011] This invention addresses the shortcomings of existing technologies by providing an automated palletizing method and equipment for leather. It aims to solve many pain points arising from the long-standing reliance on manual labor in leather handling within the traditional leather industry, achieving automated, flexible, and efficient operations. Traditional manual handling of leather, especially wet leather and wet blue leather, suffers from high labor intensity, low efficiency, and easy damage to the leather. The weight of a single piece of leather is significant, and prolonged handling can easily lead to occupational injuries such as lumbar muscle strain for workers. Furthermore, manual handling easily results in creases, scratches, or stains, directly affecting the appearance of the leather and the value of the finished product. Simultaneously, manual handling is slow and lacks continuity, making it difficult to match the pace of modern leather production lines. Moreover, the humid working environment and the presence of chemical residues pose health risks to workers who come into direct contact with them.

[0012] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, the present invention provides an automated palletizing method for leather, comprising the following steps: Step 1: Place the leather in the output area and spread it out; Step 2: The visual automatic positioning module identifies the leather edge contour and calculates the three-dimensional coordinates of multiple gripping points on the leather surface according to preset rules; Step 3: The adjustable gripping mechanism moves to the corresponding gripping point position according to the gripping point coordinates; vacuum suction is activated to smoothly lift the leather; Step 4: The transfer and palletizing mechanism swings the adjustable gripping mechanism with the leather adsorbed from above the discharge area to above the leather transfer cart; Step 5: The control system disconnects the negative pressure of each suction cup assembly in a predetermined sequence, allowing the leather to be released and stacked on the transfer vehicle; Step 6: All mechanisms are reset, awaiting the next piece of leather; For multiple sheets of leather stacked consecutively, an alternating stacking method with opposite sides is used: For the odd-numbered leather pieces, the visual automatic positioning module calculates the gripping points from the front to the middle of the leather, and disconnects the negative pressure in the order from the middle to the front during release, so that the smooth side of the leather pieces is stacked upwards. For an even-numbered piece of leather, the visual automatic positioning module calculates the gripping points from the middle to the rear of the leather, and disconnects the negative pressure in the order from the middle to the rear during release, so that the smooth side of the leather is stacked down. The smooth surfaces of two adjacent leather pieces are in contact with each other.

[0013] In a second aspect, the present invention also provides an automated palletizing device for leather, including a work rack, the work rack having an output area for placing leather, the work rack having a vision automatic positioning module, an adjustable gripping mechanism, a transfer palletizing mechanism and a control system; The visual automatic positioning module is used to acquire images of leather to be stacked, identify the edge contours of the leather, and calculate the three-dimensional coordinates of multiple gripping points on the leather surface according to preset rules. The adjustable gripping mechanism is communicatively connected to the visual automatic positioning module and is used to move to the corresponding gripping point position according to the gripping point coordinates output by the visual automatic positioning module in order to adsorb and grip the leather. The transfer and palletizing mechanism is connected to the adjustable gripping mechanism and is used to transfer the adjustable gripping mechanism with the leather adsorbed from the material picking position to the palletizing position. The control system is used to coordinate the actions of the vision-based automatic positioning module, the adjustable gripping mechanism, and the transfer and palletizing mechanism to achieve automatic positioning, gripping, transfer, and stacking of leather. For multiple leathers stacked continuously, an alternating stacking method is used to ensure that the smooth surfaces of adjacent leathers come into contact with each other.

[0014] Furthermore, the visual automatic positioning module includes a binocular camera, a light source system, and an image processing unit; the binocular camera is symmetrically installed above the discharge area to synchronously acquire binocular images of the leather; the image processing unit has a built-in image processing algorithm to process the binocular images, extract the leather outline, and calculate the three-dimensional coordinates of multiple gripping points.

[0015] Furthermore, the adjustable gripping mechanism includes a mounting frame, multiple suction cup assemblies mounted on the mounting frame, and a sliding mechanism for driving the suction cup assemblies to move independently; the suction cup assembly includes a vacuum suction cup, a vacuum generator, and a vacuum control valve.

[0016] Furthermore, the lower end face of the vacuum suction cup is provided with a flexible buffer pad, the surface of which is provided with anti-slip texture.

[0017] Furthermore, the sliding mechanism includes a horizontal sliding platform and a vertical sliding platform; multiple horizontal sliding platforms are provided, and each horizontal sliding platform independently drives a suction cup assembly to move laterally, while the vertical sliding platform drives all suction cup assemblies to rise and fall as a whole.

[0018] Furthermore, the transfer and palletizing mechanism includes a linkage mechanism and a driving component, the driving component being used to drive the linkage mechanism to swing; one end of the linkage mechanism is hinged to the work frame, and the other end is fixedly connected to the crossbeam above the discharge area; the linkage mechanism keeps the suction cup assembly of the adjustable gripping mechanism always facing downwards during the swinging process.

[0019] Furthermore, the linkage mechanism is a parallelogram linkage mechanism with a swing angle of 60°~110°.

[0020] Furthermore, the number of gripping points is eight, and the distance between the two adjustable gripping mechanisms is set as the lateral distance. The lateral distance between the gripping points is adaptively adjusted by the horizontal sliding platform according to the size of the leather.

[0021] In summary, compared with the prior art, the beneficial effects of the above technical solution are: (1) This invention adopts the principle of binocular vision positioning. The binocular industrial camera acquires images of the leather placed in the field of view. Then, the images are preprocessed to extract the leather outline and determine the effective gripping area. Next, according to the preset gripping point distribution rules, the pixel positions of eight optimal gripping points are calculated. Then, through binocular stereo matching and coordinate transformation, the pixel coordinates are converted into three-dimensional coordinates under the coordinate system of the adjustable gripping mechanism. Finally, the adjustable gripping mechanism is controlled to move the vacuum suction cup to the target position. Then, the horizontal spacing of the vacuum suction cup is adjusted by the horizontal sliding platform to make the vacuum suction cup move precisely above the gripping point. Then, the automated gripping operation of irregular leather is completed. The binocular vision positioning principle combined with the image processing algorithm realizes the outline recognition, three-dimensional depth perception and precise positioning of irregular leather. The positioning accuracy can reach ±0.5mm. At the same time, the optimal gripping point is calculated by combining the principle of force balance, which lays the foundation for stable gripping. (2) The adjustable gripping mechanism designed in this invention can achieve stepless adjustment of the lateral spacing of the gripping points through eight horizontal sliding platforms, which can be adapted to leathers of different sizes and shapes, and has a strong adaptability; at the same time, the vacuum suction cup is combined with a flexible buffer pad, which not only ensures the sealing and stability of the adsorption, but also effectively prevents scratching and crushing the leather, thus achieving non-destructive gripping of the leather. (3) The transfer and palletizing mechanism of the present invention adopts a parallelogram linkage mechanism, which structurally ensures that the suction cup always faces downward during the leather transfer process, thus solving the problem of easy slippage during the leather transfer process; (4) The present invention realizes the linkage and automated control of each mechanism through the control system, and completes the full process automation of leather from positioning, grasping to transfer and palletizing. No manual intervention is required, palletizing efficiency is improved, and the labor intensity of workers and the labor and management costs of enterprises are greatly reduced. (5) The equipment of the present invention has a compact structure and reasonable layout of each mechanism. It can be directly connected to the existing leather processing production line without the need for large-scale modification of the production line. The equipment is highly stable and easy to maintain, and has extremely high practical value and industry promotion value. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the overall structure of an embodiment of the present invention. Figure 2 ; Figure 3 for Figure 2 Enlarged view of point A in the image; Figure 4 The side view highlights the linkage mechanism and drive component in an embodiment of the present invention; Figure 5 This is a schematic diagram of the adjustable gripping mechanism in an embodiment of the present invention; Figure 6 This is a schematic diagram of eight grasping points in an embodiment of the present invention; Figure 7 This is a diagram showing the state of the odd-numbered leather pieces when they are released. Figure 8 This is a state diagram when the even-numbered leather is released.

[0023] Explanation of reference numerals in the attached drawings: 1. Working frame; 2. Discharge area; 21. Roller; 22. Crossbeam; 3. Automatic vision positioning module; 31. Binocular camera; 4. Adjustable gripping mechanism; 41. Mounting frame; 42. Vacuum suction cup; 43. Sliding mechanism; 431. Horizontal sliding platform; 432. Vertical sliding platform; 44. Connecting plate; 5. Transfer and palletizing mechanism; 51. Linkage mechanism; 52. Drive component; 6. Transfer cart; 7. Leather. Detailed Implementation

[0024] The principles and features of the present invention are described below with reference to all the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0025] This invention discloses an automated palletizing method and palletizing equipment for leather.

[0026] In a first aspect, embodiments of the present invention disclose an automated palletizing method for leather.

[0027] Reference Figures 1-8 An automated palletizing method for leather includes the following steps: Step 1: Place the leather 7 in the output area 2 and spread it out; Step 2: The visual automatic positioning module 3 identifies the edge contour of the leather 7 and calculates the three-dimensional coordinates of multiple gripping points on the surface of the leather 7 according to preset rules; Step 3: The adjustable gripping mechanism 4 moves to the corresponding gripping point position according to the gripping point coordinates; the vacuum suction is activated to smoothly lift the leather 7. Step 4: The transfer and palletizing mechanism 5 swings the adjustable gripping mechanism 4, which has the leather 7 adsorbed, from above the discharge area 2 to above the transfer vehicle 6; Step 5: The control system disconnects the negative pressure of each suction cup assembly in a predetermined sequence, so that the leather 7 is released and stacked on the transfer cart 6; Step 6: All mechanisms are reset, awaiting the next leather 7.

[0028] For multiple sheets of leather 7 stacked continuously, an alternating stacking method is used, specifically: For the odd-numbered leather 7, the visual automatic positioning module 3 calculates the gripping point from the front to the middle of the leather 7, and disconnects the negative pressure in the order from the middle to the front when releasing, so that the smooth side of the leather 7 is stacked upwards. For the even-numbered leather 7, the visual automatic positioning module 3 calculates the gripping points from the middle to the rear of the leather 7, and disconnects the negative pressure in the order from the middle to the rear when releasing, so that the smooth side of the leather 7 is stacked down. The smooth surfaces of two adjacent leather pieces 7 are in contact with each other.

[0029] The more specific process for the above steps is as follows: Step 1: The staff puts the leather 7 into the output area 2 and spreads the leather 7 out (smooth side of leather 7 facing up).

[0030] Step 2: The visual automatic positioning module 3 identifies the edge contour of the leather 7 and determines 4 gripping points on each side of the front-middle part of the surface of the leather 7, so that when the leather 7 is stacked later, its smooth side can be stacked on the transfer cart 6, avoiding direct contact between its smooth side and the transfer cart 6, so as not to scratch the leather 7.

[0031] Step 3: The adjustable gripping mechanism 4, through the eight horizontal sliding platforms 431 of the sliding mechanism 43, drives the corresponding vacuum suction cups 42 to move laterally and adjust them to the designated gripping point position. The longitudinal spacing of the gripping points is fixed at 305mm, while the lateral spacing is adaptively adjusted according to the size of the leather 7.

[0032] Step 4: After the vacuum suction cup 42 is precisely moved to the designated gripping point, the eight vacuum generators start simultaneously. The vacuum suction cup 42 adheres to the surface of the leather 7, and the flexible silicone cushioning pad adapts to the irregular surface of the leather 7 to ensure the adsorption seal, so as to smoothly and without damage lift the entire piece of leather 7 and complete the gripping action.

[0033] Step 5: The transfer and palletizing mechanism 5 is a parallelogram linkage mechanism driven by an electric push rod. When the adjustable gripping mechanism 4 picks up the leather 7, the control system sends a swing command. The parallelogram linkage mechanism drives the adjustable gripping mechanism 4 and the leather 7 to swing smoothly from the discharge area 2 to above the transfer car 6. During the swing, the vacuum suction cup 42 is always kept facing downward to prevent the leather 7 from slipping.

[0034] Step 6: The control system sends a release command, and the vacuum control valve of the release component is activated. The negative pressure of the eight vacuum suction cups 42 is disconnected in the order of middle to front. At this time, the leather 7 is released with the smooth side facing up. The leather 7 is released smoothly under its own gravity and stacked neatly on the transfer car 6, completing one stacking action. After this stacking, the leather 7 is stacked with the smooth side facing up on the transfer car 6.

[0035] Step 7: The staff puts the next piece of leather 7 into the output area 2 and lays it out (smooth side up).

[0036] Step 8: The visual automatic positioning module 3 identifies the edge contour of the leather 7 and determines four gripping points on each side of the middle to rear of the leather 7 so that the smooth side of this leather 7 can face down when stacking, and it can be stacked with the smooth side of the previous leather 7 to avoid the smooth side of the previous leather 7 directly contacting the rough side of this leather 7 and causing scratches on the leather 7.

[0037] Step 9: Repeat steps 3 through 5.

[0038] Step 10: The control system sends a release command, disconnecting the negative pressure of the eight vacuum suction cups 42 in the order of middle to rear. At this time, the leather 7 is released with its smooth side facing down. Under its own gravity, the leather 7 is released smoothly and neatly stacked on the transfer cart 6, completing one stacking action. After the two stacking operations are completed, the smooth sides of the two leathers 7 are in contact with each other, avoiding the situation where the smooth side of the previous leather 7 comes into contact with the rough side of the current leather 7, which could cause scratches to the leather 7.

[0039] Step 11: After completing one round of forward and reverse stacking of leather 7, the control system will automatically send a reset command to control the transfer stacking mechanism 5 and the adjustable gripping mechanism 4 to reset to their initial positions in sequence, waiting for the next piece of leather 7 to be transported to the discharge area 2. Then, the next round of automated stacking process will be started automatically. The whole process does not require manual intervention and realizes continuous and automated stacking.

[0040] It is particularly important to emphasize that: Assuming the odd-numbered piece of leather 7 has its smooth side facing up, during the gripping process, the vacuum suction cup 42 sequentially grips the front and middle gripping points, then moves the leather 7 along with it. When the leather 7 moves to the position of the transfer cart 6, because the upper surface of the transfer cart 6 is an arc surface, when the middle part is released first, the rear part falls down first and contacts the arc surface fulcrum. When the front part is released last, the front part simply lies flat downwards without any flipping torque, so the smooth side continues to face up. Figure 7 As shown, the direction of travel is from left to right; For even-numbered pieces of leather 7, the gripping point is from the middle to the rear, meaning the front is not gripped by the vacuum suction cup 42. When leather 7 is lifted and suspended in the air, its front (unattached end) will naturally droop downwards under gravity, while the smooth surface remains upwards, meaning the smooth surface is still in contact with the vacuum suction cup 42. Upon release, the system first disconnects the middle vacuum suction cup 42. At this point, only the rear vacuum suction cup 42 remains attached to leather 7. Leather 7 loses its middle support, its center of gravity shifts forward, and the originally drooping front accelerates downwards first. After the front falls, it will first contact the arc surface of the transfer cart 6, or the stacked upper layer of leather 7. This arc surface is convex, providing a stable physical fulcrum for the front of leather 7, preventing the front from moving further downwards. Then, the rear vacuum suction cup 42 is disconnected, and the rear of leather 7 is no longer restrained. At this point, the front of leather 7 is held in place by the arc-shaped fulcrum and remains stationary, but the rear is still in the air and continues to swing downwards under the influence of gravity. With the front fixed and the rear swinging downwards, a flipping torque is formed around the front edge (similar to turning a page in a book). In conjunction with the convex curvature of the arc surface, the rear will slide down along the arc surface, causing the entire leather 7 to tumble backwards (flip). After this flip, the smooth surface that was originally facing upwards (in contact with the suction cup) is flipped downwards, while the rough surface is flipped upwards. Therefore, this even-numbered leather 7 is finally stacked on the transfer cart with the smooth surface facing down, forming a "smooth face to smooth surface" fit with the previous odd-numbered leather 7 with the smooth surface facing up.

[0041] The even-numbered leather piece 7 is stacked by placing the middle piece first, then the back piece, intentionally with the front part landing first to act as a hinge, and the back part landing later to create a roll. The curved surface of the transfer cart serves as the protruding fulcrum that triggers this roll, ultimately achieving a stacking effect with the smooth side facing down. Figure 8 As shown, the direction of travel is from left to right.

[0042] Secondly, embodiments of the present invention also disclose an automated palletizing device for leather, used to implement the automated palletizing method for leather described in the first aspect.

[0043] Reference Figures 1-8 An automated palletizing device for leather includes a work rack 1, with a transfer cart 6 at one end for transferring leather 7. The work rack 1 has a discharge area 2 for placing the leather 7. The work rack 1 also includes a vision-based automatic positioning module 3, an adjustable gripping mechanism 4, a transfer and palletizing mechanism 5, and a control system. The control system coordinates the actions of the vision-based automatic positioning module 3, the adjustable gripping mechanism 4, and the transfer and palletizing mechanism 5 to achieve automatic positioning, gripping, transfer, and stacking of the leather 7.

[0044] The discharge area 2 is composed of multiple rollers 21 arranged in sequence, and all rollers 21 are rotatably connected to the work frame 1 and located above the work frame 1. The leather 7 is laid flat on the discharge area 2. A crossbeam 22 is provided above the discharge area 2, and the adjustable gripping mechanism 4, the transfer and palletizing mechanism 5, and the visual automatic positioning module 3 are all connected to the crossbeam 22.

[0045] The visual automatic positioning module 3 is located above the discharge area 2, at both ends of the crossbeam 22, and is used to acquire images of the leather 7 to be stacked. Specifically, the visual automatic positioning module 3 includes binocular cameras 31 mounted on the crossbeam 22 above the discharge area 2, a light source system, and an image processing unit. Two binocular cameras 31 are provided and symmetrically installed. In this embodiment, the two binocular cameras 31 form a fixed baseline distance of 2500mm, and their shooting frame rate and exposure parameters are kept consistent to synchronously acquire binocular images of the leather 7. The light source system is an LED surface light source structure, located below the binocular cameras 31. In this embodiment, its light intensity is adjusted to 600 lux to provide uniform illumination for the imaging of the leather 7, effectively eliminating shadows and reflections on the surface of the leather 7 and ensuring image quality. The image processing unit has a built-in image processing algorithm to process the acquired binocular images and output the actual position, posture, and coordinates of eight gripping points of the leather 7, which are then transmitted to the control system.

[0046] It should be noted that the binocular vision positioning image processing algorithm first acquires target images simultaneously using left and right industrial cameras. Then, the images undergo preprocessing operations such as grayscale conversion, filtering and noise reduction, and contrast enhancement to eliminate environmental noise and optimize image quality. Prior to this, binocular camera calibration is completed, and distortion correction and stereo correction are performed after acquiring the camera's intrinsic and extrinsic parameters. The epipolar lines of the left and right images are aligned to reduce the matching search range. Subsequently, SGBM or SGM algorithms are used to perform stereo matching of the left and right images, generating a disparity map. Based on the binocular triangulation formula, depth information is calculated from the disparity data to generate a 3D point cloud of the target. Next, the Canny operator is used to perform edge detection and contour fitting, extracting the complete outer contour of the target. Then, the image pixel coordinates are converted to device world coordinates to calculate the actual spatial pose of the target. Finally, the 3D coordinates of each grasping point are calculated based on the grasping arrangement rules, and the positioning data is output to the control system to complete the grasping and positioning.

[0047] Among them, SGBM, or SGM, is the core algorithm for calculating depth in binocular vision. Its full name is Semi-Global Block Matching, which strikes a balance between accuracy and speed. It is mainly used to calculate the 3D depth information of a scene using two images, and is a common tool in robotics and autonomous driving.

[0048] This image processing algorithm is implemented by combining well-known and classic algorithms such as Zhang Zhengyou calibration method, Bouguet stereo correction, SGM / SGBM stereo matching, Canny edge detection, Gaussian filtering preprocessing, and binocular triangulation. These algorithms were published by scholars at home and abroad in international journals, academic conferences and classic image processing textbooks between 1977 and 2005. All of them have been included in open-source vision libraries such as OpenCV and belong to existing mature technologies that are well-known and widely used in this field.

[0049] The adjustable gripping mechanism 4 includes a sliding mechanism 43, a suction cup assembly, and a mounting frame 41. Two adjustable gripping mechanisms 4 are provided, located at opposite ends of the crossbeam 22 above the discharge area 2. The sliding mechanism 43 consists of a vertical sliding platform 432 and a horizontal sliding platform 431. The mounting frame 41 is made of aluminum alloy profile, which is lightweight and high-strength. The lower part of the mounting frame 41 connects to the suction cup assembly and the horizontal sliding platform 431, while the upper part of the mounting frame 41 is connected to the vertical sliding platform 432 via a connecting plate 44. The vertical sliding platform 432 is an electric lead screw feed platform with a stroke of 800mm, used to drive the suction cup assembly to move up and down to achieve height changes.

[0050] The adjustable gripping mechanism 4 designed in this embodiment of the invention achieves stepless adjustment of the lateral spacing of the gripping points through eight horizontal sliding platforms 431, which can adapt to leather 7 of different sizes and shapes, and has extremely strong adaptability; at the same time, the vacuum suction cup 42 is equipped with a silicone flexible buffer pad, which not only ensures the sealing and stability of the adsorption, but also effectively prevents scratches and pressure damage to the leather 7, so as to achieve non-destructive gripping of the leather 7.

[0051] Each adjustable gripping mechanism 4 includes four vacuum suction cups 42, each connected to a vacuum generator and an independent vacuum control valve. The vacuum suction cup 42 adsorbs the leather 7 via the vacuum generator and vacuum control valve. It should be noted that the vacuum control valve, vacuum generator, and vacuum suction cups 42 are connected in an orderly manner via pneumatic pipelines, forming a complete vacuum adsorption system. Compressed air enters the vacuum generator from the air source via the vacuum control valve, the vacuum generator creates a vacuum, and then the vacuum is transmitted to the vacuum suction cups 42 through the pipeline to complete the adsorption.

[0052] Each vacuum suction cup 42 has a flexible buffer pad made of silicone material on its lower end face. In this embodiment, the thickness of the flexible buffer pad is 3-5mm, and its surface is provided with anti-slip texture to conform to the irregular surface of the leather 7, ensure the adsorption and sealing, and prevent scratches on the surface of the leather 7.

[0053] The number of horizontal sliding platforms 431 corresponds one-to-one with the number of vacuum suction cups 42. That is, four horizontal sliding platforms 431 are provided under each mounting bracket 41, and the four horizontal sliding platforms 431 are arranged along the length of the mounting bracket 41. The horizontal sliding platform 431 is an electric lead screw feeding platform, and in this embodiment, its stroke is 500mm and its positioning accuracy is ±0.5mm. The longitudinal spacing of the eight gripping points remains fixed, while the lateral spacing is adjusted by the horizontal sliding platforms 431 to accommodate irregular leather 7 of different sizes and shapes. After the adjustable gripping mechanism 4 receives the gripping point coordinates from the visual automatic positioning module 3, it drives the corresponding vacuum suction cup 42 to move precisely to the designated gripping point position through the horizontal sliding platform 431, completing the adsorption and gripping of the leather 7.

[0054] It should be noted that in this embodiment, the horizontal spacing between the gripping points is mainly adjusted by the horizontal sliding platform 431, that is, it is adjusted for narrower leather 7, while for longer or shorter leather 7, the suction cup components of each group of four in this embodiment can achieve the adsorption effect on the leather 7.

[0055] The transfer and palletizing mechanism 5 includes a linkage mechanism 51 and a drive component 52. In this embodiment, two linkage mechanisms 51 are provided, located on both sides of the work frame 1. The linkage mechanism 51 is a parallelogram linkage mechanism with a swing angle of 60°~110°. The bottom end of the parallelogram linkage mechanism 51 is hinged to the work frame 1, and the other end is fixedly connected to the crossbeam 22 above the discharge area 2. The linkage mechanism 51 is used to drive the sucked-up leather 7 to swing smoothly from the discharge area 2 to above the transfer cart 6. The structural characteristics of the parallelogram linkage mechanism can ensure that the vacuum suction cup 42 of the adjustable gripping mechanism 4 always faces downward during the swinging process, preventing the leather 7 from slipping due to gravity.

[0056] In this embodiment, the driving component 52 is an electric actuator. The base of the electric actuator is hinged to the working frame 1, and the extended end of the electric actuator is hinged to the linkage mechanism 51, which is used to drive the parallelogram linkage mechanism to swing.

[0057] This invention employs a binocular vision positioning principle. A binocular camera 31 acquires images of the leather 7 placed within the field of view. The images are then pre-processed to extract the outline of the leather 7 and determine the effective gripping area. Next, based on a preset gripping point distribution rule, the pixel positions of eight optimal gripping points are calculated. Then, through binocular stereo matching and coordinate transformation, the pixel coordinates are converted into three-dimensional coordinates in the adjustable gripping mechanism's coordinate system. The control system controls the adjustable gripping mechanism 4 to move the vacuum suction cup 42 to the target position. Then, the horizontal sliding platform 431 adjusts the lateral spacing of the vacuum suction cup 42 to precisely move it above the gripping point, thus completing the automated gripping of the irregular leather 7. The binocular vision positioning principle, combined with image processing algorithms, achieves outline recognition, three-dimensional depth perception, and precise positioning of the irregular leather 7, with a positioning accuracy of ±0.5mm. Simultaneously, the optimal gripping point is calculated based on the force balance principle, laying the foundation for stable gripping.

[0058] The preset gripping point distribution rules are as follows: a total of eight gripping points are set on the entire cowhide (leather), four on each side, symmetrically distributed along the center line of the cowhide. The gripping points are concentrated on both sides of the middle of the cowhide, avoiding the edges and easily deformable areas. The longitudinal distance between the four gripping points on the same side remains constant to ensure basic adsorption stability. The lateral spacing of the symmetrical points on opposite sides is independently adjustable (via a horizontal sliding platform) to adapt to cowhides of different lengths and irregular shapes.

[0059] The pixel positions of eight optimal grasping points were calculated as follows: First, the left and right images of the cowhide were simultaneously acquired using a binocular vision system. After denoising, grayscale conversion, and edge enhancement preprocessing, a disparity map was generated through stereo matching, and a depth map was calculated in conjunction with camera calibration parameters. Then, the cowhide edge contour was extracted from the depth map or grayscale map and curve fitting was performed to generate a two-dimensional contour map and a three-dimensional point cloud model of the cowhide. Next, the minimum bounding rectangle of the cowhide was determined in the two-dimensional contour map, and the centerline was extracted. The planar area was divided into two symmetrical parts, and initial candidate points were generated in the middle areas of both sides at a fixed vertical spacing. Then, candidate points were selected based on the principles of contour curvature, safe distance from the edge, and force balance. Subsequently, the lateral position of the candidate points was iteratively adjusted through optimization algorithms (such as center of gravity balance and minimum deformation energy) so that the lateral spacing of the four points on the same side adapted to the width and shape of the cowhide. Finally, the two-dimensional pixel coordinates of the eight optimal grasping points, four on each side, were determined.

[0060] Then, through binocular stereo matching and coordinate transformation, the pixel coordinates are converted into three-dimensional coordinates in the coordinate system of the adjustable gripping mechanism. Specifically, the following steps are taken: First, images of the cowhide are simultaneously acquired and calibrated using binocular cameras to obtain the intrinsic parameters, distortion coefficients, and extrinsic parameters (baseline, rotation / translation relationship) of the left and right cameras. After image preprocessing, binocular stereo matching is performed to calculate the disparity of corresponding points. The depth of each pixel is then calculated using triangulation formulas to obtain the three-dimensional coordinates (Xc, Yc, Zc) of the points on the cowhide surface in the camera coordinate system. This three-dimensional point cloud is then transformed from the camera coordinate system to the device base coordinate system using the transformation matrix (R, T) obtained from hand-eye calibration. Finally, combined with the installation pose of the adjustable gripping mechanism, the base coordinate system coordinates are further converted into three-dimensional coordinates (Xg, Yg, Zg) in the gripping mechanism coordinate system using the mechanism fixed transformation matrix (R0, T0). This result is then output to the control system, driving the suction cup to accurately reach the eight optimal gripping point positions.

[0061] It should be emphasized that the positions of the gripping points are not evenly distributed. Therefore, the horizontal spacing of the vacuum suction cups 42 can be adjusted by the horizontal sliding platform 431 to correspond to the position of the gripping points. That is, the sliding distance of each horizontal sliding platform 431 can be the same or different. Its sliding distance and position need to correspond to the gripping points to facilitate gripping the leather.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An automated palletizing method for leather, characterized in that, Includes the following steps: Step 1: Place the leather (7) in the output area (2) and spread it out; Step 2: The visual automatic positioning module (3) identifies the edge contour of the leather (7) and calculates the three-dimensional coordinates of multiple gripping points on the surface of the leather (7) according to preset rules; Step 3: The adjustable gripping mechanism (4) moves to the corresponding gripping point position according to the gripping point coordinates; the vacuum adsorption is activated to smoothly lift the leather (7); Step 4: The transfer and palletizing mechanism (5) swings the adjustable gripping mechanism (4) with the leather (7) adsorbed on it from above the discharge area (2) to above the transfer cart (6) of the leather (7); Step 5: The control system disconnects the negative pressure of each suction cup assembly in a predetermined sequence, so that the leather (7) is released and stacked on the transfer vehicle (6); Step 6: All mechanisms are reset, awaiting the next piece of leather (7); For multiple sheets of leather (7) stacked consecutively, an alternating stacking method is adopted: For the odd-numbered leather (7), the visual automatic positioning module (3) calculates the gripping point from the front to the middle of the leather (7), and disconnects the negative pressure in the order from the middle to the front when releasing, so that the smooth side of the leather (7) is stacked up; For the even-numbered leather (7), the visual automatic positioning module (3) calculates the gripping points from the middle to the back of the leather (7), and disconnects the negative pressure in the order from the middle to the back when releasing, so that the smooth side of the leather (7) is stacked down. The smooth surfaces of two adjacent leather pieces (7) are in contact with each other.

2. An automated palletizing device for leather, characterized in that, To implement an automated palletizing method for leather as described in claim 1, the method includes a work rack (1), the work rack (1) having a discharge area (2) for placing leather (7), the work rack (1) having a vision automatic positioning module (3), an adjustable gripping mechanism (4), a transfer palletizing mechanism (5) and a control system. The visual automatic positioning module (3) is used to acquire images of the leather (7) to be stacked, identify the edge contour of the leather (7), and calculate the three-dimensional coordinates of multiple gripping points on the surface of the leather (7) according to preset rules. The adjustable gripping mechanism (4) is communicatively connected to the visual automatic positioning module (3) and is used to move to the corresponding gripping point position according to the gripping point coordinates output by the visual automatic positioning module (3) in order to adsorb and grip the leather (7). The transfer and palletizing mechanism (5) is connected to the adjustable gripping mechanism (4) and is used to transfer the adjustable gripping mechanism (4) with the leather (7) adsorbed from the material picking position to the palletizing position; The control system is used to coordinate the actions of the visual automatic positioning module (3), the adjustable gripping mechanism (4) and the transfer and palletizing mechanism (5) to realize the automatic positioning, gripping, transfer and stacking of leather (7); For multiple leathers (7) stacked continuously, an alternating stacking method is used to stack them so that the smooth surfaces of two adjacent leathers (7) come into contact with each other.

3. An automated palletizing device for leather according to claim 2, characterized in that: The visual automatic positioning module (3) includes a binocular camera (31), a light source system and an image processing unit; the binocular camera (31) is symmetrically installed above the discharge area (2) to synchronously acquire binocular images of the leather (7); the image processing unit has a built-in image processing algorithm to process the binocular images, extract the outline of the leather (7) and calculate the three-dimensional coordinates of multiple gripping points.

4. An automated palletizing device for leather according to claim 2, characterized in that: The adjustable gripping mechanism (4) includes a mounting frame (41), a plurality of suction cup assemblies mounted on the mounting frame (41), and a sliding mechanism (43) for driving the suction cup assemblies to move; the suction cup assembly includes a vacuum suction cup (42), a vacuum generator, and a vacuum control valve.

5. An automated palletizing device for leather according to claim 4, characterized in that: The sliding mechanism (43) includes a horizontal sliding platform (431) and a vertical sliding platform (432); there are multiple horizontal sliding platforms (431), and each horizontal sliding platform (431) independently drives a suction cup assembly to move laterally, and the vertical sliding platform (432) drives all suction cup assemblies to rise and fall as a whole.

6. An automated palletizing device for leather according to claim 2, characterized in that: The transfer and palletizing mechanism (5) includes a linkage mechanism (51) and a drive member (52). The drive member (52) is used to drive the linkage mechanism (51) to swing. One end of the linkage mechanism (51) is hinged to the work frame (1), and the other end is fixedly connected to the crossbeam (22) above the discharge area (2). During the swinging process, the linkage mechanism (51) keeps the suction cup assembly of the adjustable gripping mechanism (4) facing downward.

7. An automated palletizing device for leather according to claim 6, characterized in that: The linkage mechanism (51) is a parallelogram linkage mechanism with a swing angle of 60°~110°.

8. An automated palletizing device for leather according to claim 5, characterized in that: The number of gripping points is eight, and the distance between the two adjustable gripping mechanisms (4) is set as the horizontal distance. The horizontal distance between the gripping points is adaptively adjusted by the horizontal sliding platform (431) according to the size of the leather.

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