Sorting robot and control method thereof

Abstract

The present invention discloses a sorting robot and a control method thereof, wherein the sorting robot comprises a mounting seat, a left clamping jaw arranged on the mounting seat through a first rotating shaft, a right clamping jaw arranged on the mounting seat through a second rotating shaft, and a driving mechanism for driving the left clamping jaw and the right clamping jaw to rotate, wherein the structures of the left clamping jaw and the right clamping jaw are symmetrical and symmetrically arranged, and the sorting robot further comprises a transmission belt for placing materials to be grasped, and the distance from the first rotating shaft to the grasping point of the left clamping jaw on the materials to be grasped in a direction perpendicular to the materials to be grasped is defined as h, if c≥b, then if c<b, then wherein c is the width of the materials to be grasped, b is the axial center distance between the first rotating shaft and the second rotating shaft, and a is the length of the left clamping jaw. The sorting robot and the control method thereof provided by the present invention can grasp materials accurately and have higher sorting efficiency.

Description

Technical Field

[0001] The invention relates to a sorting robot and a control method thereof. Background Art

[0002] There are two main types of existing robot sorting technologies. The first is the air suction cup, which is a method where the robot generates negative pressure on the surface in contact with the material, thereby adsorbing the material and then grabbing the material. However, due to the limitations of the suction cup working principle and the performance of the vacuum pump, this type of robot is only suitable for grabbing light and smooth materials. It is difficult to grab heavy or rough materials through negative pressure adsorption.

[0003] The second type is a hand-grasping mechanical gripper, which is a robot that grabs materials in a way that simulates human hands. In this method, whether the surface of the material is smooth has no effect on the robot's grasping, and it is suitable for grasping heavier materials. Construction waste contains a lot of metal, heavy wood, red bricks and other materials. This type of hand-grasping mechanical gripper can sort construction waste. However, the arc-shaped closed trajectory of the mechanical gripper makes it difficult to achieve effective sorting when grasping materials with smaller widths and thinner thicknesses.

[0004] In addition, in the traditional sorting method, the gripper is set to open a fixed stroke at the beginning of grasping, which not only increases the grasping time, but also affects the grasping effect of some special materials. Summary of the invention

[0005] The object of the present invention is to provide a sorting robot and a control method thereof, which can accurately grasp materials and have higher sorting efficiency.

[0006] To achieve one of the above-mentioned purposes of the invention, an embodiment of the present invention provides a sorting robot, characterized in that the sorting robot comprises a mounting seat, a left clamping jaw arranged on the mounting seat through a first rotating shaft, a right clamping jaw arranged on the mounting seat through a second rotating shaft, and a driving mechanism for driving the left clamping jaw and the right clamping jaw to rotate, the left clamping jaw and the right clamping jaw have symmetrical structures and are symmetrically arranged, the sorting robot also comprises a transmission belt for placing materials to be grasped, and the distance from the first rotating shaft to the grasping point of the left clamping jaw on the material to be grasped in a direction perpendicular to the material to be grasped is defined as h, if c≥b, then ; If c<b, then , where c is the width of the material to be grabbed, b is the axis distance between the first rotating shaft and the second rotating shaft, a is the length of the left gripper.

[0007] As a further improvement of one embodiment of the present invention, the sorting robot also includes a control unit for controlling the movement of the left jaw and the right jaw and an image unit electrically connected to the control unit, the image unit is used to obtain material parameters of the material, the material parameters are transmitted to the control unit, the control unit calculates and processes the material parameters and controls the movement of the left jaw and the right jaw.

[0008] As a further improvement of an embodiment of the present invention, the opening stroke of the lowermost end point of the left jaw and the lowermost end point of the right jaw before each grasping is defined as S, S=c+2x, wherein x is the additional grasping threshold of the material to be grasped, and if c≥b, then x≥△c, and △c is the system error of the sorting robot.

[0009] As a further improvement of an embodiment of the present invention, the opening stroke of the lowermost end point of the left jaw and the lowermost end point of the right jaw before each grasping is defined as S, S=c+2x, wherein x is the additional grasping threshold of the material to be grasped, if c2(a-h), then x≥△c, △c is the system error of the sorting robot.

[0010] As a further improvement of an embodiment of the present invention, ,in is the error caused by the time difference of image processing, is the contour offset error in image processing, is the sorting robot body error.

[0011] As a further improvement of an embodiment of the present invention, it is defined that before each grasping, the opening stroke of the lowermost end point of the left clamp and the lowermost end point of the right clamp is S, S=c+2 ,in is the additional grab threshold for the material to be grabbed, where c < b and d , .

[0012] To achieve one of the above-mentioned purposes of the invention, an embodiment of the present invention further provides a control method for a sorting robot, characterized in that the sorting robot comprises a mounting seat, a left clamping jaw arranged on the mounting seat via a first rotating shaft, a right clamping jaw arranged on the mounting seat via a second rotating shaft, and a driving mechanism for driving the left clamping jaw and the right clamping jaw to rotate, the left clamping jaw and the right clamping jaw have symmetrical structures and are symmetrically arranged, the sorting robot further comprises a transmission belt for placing materials to be grasped, the axial center distance between the first rotating shaft and the second rotating shaft is b, and the control method comprises the following steps:

[0013] Confirm the width c and thickness d of the material;

[0014] Define the distance from the first rotating axis to the gripping point of the left gripper on the material to be gripped in the direction perpendicular to the material to be gripped as h, compare the sizes of c and b, if c ≥ b, then ; If c<b, then .

[0015] As a further improvement of one embodiment of the present invention, the sorting robot also includes a control unit for controlling the movement of the left jaw and the right jaw and an image unit electrically connected to the control unit, the image unit is used to obtain material parameters width c and thickness d of the material, the width c and thickness d are transmitted to the control unit, and the control unit analyzes the width c, thickness d and axial center distance b and calculates the distance h.

[0016] As a further improvement of an embodiment of the present invention, the opening stroke of the lowermost end point of the left jaw and the lowermost end point of the right jaw before each grasping is defined as S, S=c+2x, wherein x is the additional grasping threshold of the material to be grasped, and if c≥b, then x≥△c, and △c is the system error of the sorting robot.

[0017] As a further improvement of an embodiment of the present invention, it is defined that before each grasping, the opening stroke of the lowermost end point of the left clamp and the lowermost end point of the right clamp is S, S=c+2 ,in is the additional grab threshold for the material to be grabbed, where c < b and d , .

[0018] Compared with the prior art, in the technical solution provided by the present invention, the corresponding h value can be calculated according to the size relationship between the material width c and the axial center distance b between the two rotating shafts, that is, the positions of the left clamp and the right clamp in the direction perpendicular to the material are adjusted into place, so that the material can be accurately grasped and the sorting efficiency is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of a sorting robot in a specific embodiment of the present invention;

[0020] Figure 2 It is a schematic diagram of the motion trajectories of the lower end points of the left gripper and the right gripper of the sorting robot in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be described in detail below in conjunction with the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0022] In various drawings of the present application, for the convenience of illustration, some sizes of structures or parts are exaggerated relative to other structures or parts, and thus, are only used to illustrate the basic structure of the subject matter of the present application.

[0023] In addition, terms such as "upper", "above", "lower", "below", etc. used herein to indicate spatial relative positions are used for the purpose of convenience to describe the relationship of one unit or feature relative to another unit or feature as shown in the drawings. Terms of spatial relative position may be intended to include different orientations of the device in use or operation other than the orientation shown in the drawings. For example, if the device in the figure is turned over, the unit described as being "below" or "beneath" other units or features will be located "above" the other units or features. Therefore, the exemplary term "below" can encompass both the above and below orientations. The device may be oriented in other ways (rotated 90 degrees or other orientations), and the spatially related descriptors used herein shall be interpreted accordingly.

[0024] like Figure 1 As shown, the present invention discloses a sorting robot, which includes a mounting seat 10, a left clamping jaw 14 provided on the mounting seat 10 through a first rotating shaft 12, a right clamping jaw 18 provided on the mounting seat 10 through a second rotating shaft 16, and a driving mechanism for driving the left clamping jaw 14 and the right clamping jaw 18 to rotate. The left clamping jaw 14 and the right clamping jaw 18 have symmetrical structures and are symmetrically arranged. The sorting robot also includes a transmission belt for placing a material 20 to be grasped. The left clamping jaw 14 can be driven to rotate around the first rotating shaft 12, and the right clamping jaw 18 can be driven to rotate around the second rotating shaft 16, and the left clamping jaw 14 and the right clamping jaw 18 rotate synchronously.

[0025] Further references Figure 2 , the movement trajectory of the left clamping jaw 14 and the right clamping jaw 18 in the process of closing from the maximum opening stroke to the closed state is two symmetrical arcs, and the arcs have a minimum point. In order to prove this conclusion, the closing process trajectory analysis can be performed on the lower end point of the clamping jaw with a maximum opening stroke of 500mm and an axial center distance of 200mm between the first rotating shaft 12 and the second rotating shaft 16.

[0026] From the trajectory analysis, it can be seen that when the jaw opening stroke is 400mm, the coordinates of the lower end points of the left jaw 14 and the right jaw 18 are -282mm, and during the retraction process, the coordinates of the lower end points of the left jaw 14 and the right jaw 18 gradually decrease. When the lower ends of the left jaw 14 and the right jaw 18 are retracted to a position where the axial center distance between the first rotating shaft 12 and the second rotating shaft 16 is equal, that is, when the left jaw 14 and the right jaw 18 are approximately perpendicular to the ground, the left jaw 14 and the right jaw 18 reach the lowest point, and then in the process of retracting to the closed state, the coordinates of the lower end points of the left jaw 14 and the right jaw 18 gradually increase.

[0027] Through analysis, it can be known that in the process of the left jaw 14 and the right jaw 18 moving from the maximum opening stroke to the closing stroke, the movement trajectory of the lower end points of the left jaw 14 and the right jaw 18 is an arc that first descends and then rises. The lowest point of the trajectory is when the opening stroke of the left jaw 14 and the right jaw 18 is equal to the axial center distance between the first rotating shaft 12 and the second rotating shaft 16. This means that thin plate materials of different sizes have different effects on the robot's grasping effect. Therefore, this embodiment proposes a sorting robot and a control method thereof that executes different motion control strategies according to materials of different sizes.

[0028] In order to protect the mechanical structure of the left clamp 14 and the right clamp 18, when the left clamp 14 and the right clamp 18 are lowered to grab the material, it is necessary to avoid direct collision between the left clamp 14 and the right clamp 18 and the transmission belt, so it should be ensured that the clamp can still open and close freely without touching the transmission belt at the lowest position. When grabbing some thicker materials, the left clamp 14 and the right clamp 18 can complete the grabbing task safely and effectively, but when facing some thinner materials, the left clamp 14 and the right clamp 18 have the risk of hitting the transmission belt during the grabbing process, especially when the material is narrow, the left clamp 14 and the right clamp 18 may not be able to grab the material. Different grabbing schemes can be adopted according to the different sizes of the specific material 20 to be grabbed, thereby ensuring that the left clamp 14 and the right clamp 18 will not touch the transmission belt, and greatly improving the sorting efficiency.

[0029] Specifically, the distance from the first rotating shaft 12 to the grasping point of the left clamping claw 14 on the material 20 to be grasped in the direction perpendicular to the material 20 to be grasped is defined as h. If c ≥ b, then ; If c<b, then , where c is the width of the material 20 to be grasped, b is the axial distance between the first rotating shaft 12 and the second rotating shaft 16, and a is the length of the left clamping jaw 14. Since the structures of the left clamping jaw 14 and the right clamping jaw 18 are symmetrical, the length of the right clamping jaw 18 is the same as that of the left clamping jaw 14, and the length of the right clamping jaw 18 is also a.

[0030] When c=b, that is, the material width is just equal to the axis distance between the first rotating shaft 12 and the second rotating shaft 16, which means that when the sorting robot grabs the material, the left clamp 14 and the right clamp 18 are at right angles to the horizontal plane. In this case, since the grabbing positions of the left clamp 14 and the right clamp 18 are the minimum coordinates of their lower end points, there will be no collision between the left clamp 14 and the right clamp 18 and the transmission belt. b, that is, when the material width is greater than the axial center distance between the first rotating shaft 12 and the second rotating shaft 16, the gripping positions of the left clamp 14 and the right clamp 18 are also the minimum coordinates of their lower end points, so there will be no collision problem between the left clamp 14 and the right clamp 18 and the transmission belt.

[0031] This preferred embodiment can calculate the corresponding h value according to the size relationship between the material width c and the axial center distance b between the two rotating shafts, that is, adjust the positions of the left clamp 14 and the right clamp 18 in the direction perpendicular to the material to the right position, so that the material can be accurately grasped and the sorting efficiency is higher.

[0032] When c<b, that is, when the material width is smaller than the axial center distance between the first rotating shaft 12 and the second rotating shaft 16, the gripping position of the left jaw 14 and the right jaw 18 is not the minimum coordinate of the lower end point, and the minimum coordinate point of the lower end point of the left jaw 14 and the right jaw 18 is a certain point in the gripping process. At this time, in order to avoid the left jaw 14 and the right jaw 18 from colliding with the transmission belt, it is necessary to further set the opening stroke of the lower end point of the left jaw 14 and the lower end point of the right jaw 18 before each gripping.

[0033] Specifically, the opening stroke of the left and right jaws 14 and 18 before each grasping is defined as S, then S=c+2x, where x is the additional grasping threshold of the material 20 to be grasped, and if c≥b, then x≥△c, △c is the system error of the sorting robot. In addition, if c2(a-h), then x is also set to x≥△c. At this time, the left and right jaws 14 and 18 will not collide with the transmission belt, and the sorting efficiency is relatively high. Furthermore, x △c .

[0034] Preferably, the sorting robot further comprises a control unit for controlling the movement of the left clamp 14 and the right clamp 18 and an image unit electrically connected to the control unit, the image unit being used to obtain material parameters of the material, the material parameters being transmitted to the control unit, the control unit calculating and processing the material parameters and controlling the movement of the left clamp 14 and the right clamp 18. Of course, the material parameters can also be manually input into the control unit. Specifically, the image unit is used to obtain the material parameters width c and thickness d of the material, the width c and thickness d are transmitted to the control unit, the control unit analyzes the width c, thickness d and the axis center distance b and calculates the distance h.

[0035] Furthermore, ,in is the error caused by the time difference of image processing, is the contour offset error in image processing, is the sorting robot body error.

[0036] Specifically, it takes a certain amount of time for the image unit to process the material information on the conveyor belt. Differences in material type, color, and density will also have a certain impact on the processing speed. Therefore, the time difference of each transmission of the image unit is different. Assuming that the image unit takes t seconds to process a photo, and the conveyor belt moves at a speed of v, when the sorting robot receives the material location information t seconds later, it is actually the location of the material t seconds ago. The error caused by the processing time difference is =(v• t).

[0037] The contour offset error in image processing is determined by the camera performance of the image unit. When the camera captures moving materials, the captured image may be out of focus and the edges may be blurred, making it impossible to accurately identify the image contour, resulting in errors. Taking the Basler acA4112-8gc GigE camera as an example, the contour error in the conveying direction of the conveyor belt is within 0.5mm, and the contour error perpendicular to the conveying direction of the conveyor belt is within 0.3mm. Therefore, if this model of camera is used, the camera error should be set to 0.5mm, which is the contour offset error in image processing. It is set to 0.5mm; therefore, when different cameras are used, the error value corresponding to the camera is used.

[0038] The sorting robot has different mechanical structures. The structure of the sorting robot will wear out over time, resulting in decreased motor accuracy and shortened module life, which will cause errors. Taking the aluminum alloy four-axis gantry module with a size of 2650mm*3230mm as an example, the mechanical structure error of 3000 hours of use is 2.5mm in the conveying direction of the transmission belt and 1.3mm perpendicular to the conveying direction of the transmission belt. Set to 2.5mm.

[0039] In addition, when c<b and d To avoid collision between the left and right jaws 14 and 18 and the transmission belt, the grasping threshold needs to be adjusted. The opening stroke of the left and right jaws 14 and 18 before each grasping is still defined as S, then S=c+2 ,in is the additional grabbing threshold of the material 20 to be grabbed, wherein, Therefore, the sorting robot provided in this embodiment can adaptively adjust different grabbing thresholds according to different material parameters, thereby ensuring that the left clamping jaw 14 and the right clamping jaw 18 do not touch the transmission belt, and the sorting efficiency is higher.

[0040] This embodiment also provides a control method for a sorting robot, the control method comprising the following steps:

[0041] Confirm the width c and thickness d of the material;

[0042] Define the distance from the first rotating shaft 12 to the grasping point of the left clamp 14 on the material 20 to be grasped in the direction perpendicular to the material 20 to be grasped as h, compare the sizes of c and b, if c ≥ b, then ; If c<b, then .

[0043] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0044] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sorting robot, characterized in that: The sorting robot comprises a mounting seat, a left clamping jaw arranged on the mounting seat via a first rotating shaft, a right clamping jaw arranged on the mounting seat via a second rotating shaft, and a driving mechanism for driving the left clamping jaw and the right clamping jaw to rotate. The left clamping jaw and the right clamping jaw have symmetrical structures and are arranged symmetrically. The sorting robot also comprises a transmission belt for placing materials to be grasped. The distance from the first rotating shaft to the grasping point of the left clamping jaw on the material to be grasped in a direction perpendicular to the material to be grasped is defined as h. If c≥b, then ; If c < b, then , where c is the width of the material to be grabbed, b is the axis distance between the first rotating shaft and the second rotating shaft, a is the length of the left gripper; Define the opening stroke of the lowermost end point of the left gripper and the lowermost end point of the right gripper before each grasping as S, if c≥b, or c2(a-h), then S=c+2x, x≥△c, where x is the additional grasping threshold of the material to be grasped, △c is the system error of the sorting robot, and d is the thickness of the material; If c < b and d , then S=c+2 ,in, A gripping threshold value is added to the material to be gripped, wherein the gripping threshold value is used to prevent the left clamping jaw and the right clamping jaw from colliding with the transmission belt.

2. The sorting robot according to claim 1, characterized in that: The sorting robot also includes a control unit for controlling the movement of the left jaw and the right jaw and an image unit electrically connected to the control unit, wherein the image unit is used to obtain material parameters of the material, which are transmitted to the control unit, and the control unit calculates and processes the material parameters and controls the movement of the left jaw and the right jaw, and the image unit is used to obtain the width and thickness of the material to be grasped, which are transmitted to the control unit, and the control unit calculates the distance based on the width, the thickness and the axial center distance.

3. The sorting robot according to claim 2, characterized in that: ,in is the error caused by the time difference of image processing, is the contour offset error in image processing, is the sorting robot body error.

4. The sorting robot according to claim 2, characterized in that: If c<b and d≤2(ah), then S=c+2x s , where the definition .

5. A control method for a sorting robot, characterized in that: The sorting robot comprises a mounting seat, a left clamping jaw arranged on the mounting seat via a first rotating shaft, a right clamping jaw arranged on the mounting seat via a second rotating shaft, and a driving mechanism for driving the left clamping jaw and the right clamping jaw to rotate, the left clamping jaw and the right clamping jaw are symmetrical in structure and symmetrically arranged, the sorting robot further comprises a transmission belt for placing materials to be grasped, the axial center distance between the first rotating shaft and the second rotating shaft is b, the length of the left clamping jaw is a, and the control method comprises the following steps: Confirm the width c and thickness d of the material; Define the distance from the first rotating axis to the gripping point of the left gripper on the material to be gripped in the direction perpendicular to the material to be gripped as h, compare the sizes of c and b, if c ≥ b, then ; If c < b, then ; Define the opening stroke of the lowermost end point of the left gripper and the lowermost end point of the right gripper before each grasping as S, if c≥b, or c2(a-h), then S=c+2x, x≥△c, where x is the additional grasping threshold of the material to be grasped, and △c is the system error of the sorting robot; If c < b and d , then S=c+2 ,in, A gripping threshold value is added to the material to be gripped, wherein the gripping threshold value is used to prevent the left clamping jaw and the right clamping jaw from colliding with the transmission belt.

6. The control method according to claim 5, characterized in that: The sorting robot also includes a control unit for controlling the movement of the left gripper and the right gripper and an image unit electrically connected to the control unit, wherein the image unit is used to obtain material parameters width c and thickness d of the material, and the width c and thickness d are transmitted to the control unit, and the control unit analyzes the width c, thickness d and axial center distance b and calculates the distance h.

7. The control method according to claim 5, characterized in that: If c<b and d≤2(ah), then S=c+2x s , where the definition .

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