Package grabbing collision detection method

Abstract

A package grabbing collision detection method relates to the field of mechanical control technology. The method sets a cylindrical virtual suction cup surrounding a package grabbing suction cup in the package grabbing camera coordinate system, and then judges the operation path of the package grabbing suction cup to grab the target package. If the package grabbing suction cup moves along the operation path to the position closest to the obstacle, and the distance between the line connecting the center points of the upper and lower end faces of the virtual suction cup and the obstacle is less than the radius of the virtual suction cup, the obstacle is determined to be a risk obstacle, indicating that there is a collision risk in the operation path of the package grabbing suction cup. The method then reselects a target package until a target package without collision risk is selected and then grabs it.

Description

Technical Field

[0001] The present invention relates to mechanical control technology, and in particular to a package grabbing collision detection method. Background Art

[0002] Logistics express sorting centers handle a large number of express parcels every day. After arriving at the sorting center, these express parcels are stacked in designated parcel stacking areas. The camera in the automatic parcel sorting system captures the parcel image and controls the suction cup on the robotic arm based on the parcel image to grab the stacked parcels one by one and place them on the fully automatic conveying and sorting line for conveying and sorting to complete the operation.

[0003] However, when the robotic arm grasps the target package, the suction cup on the robotic arm may sometimes collide with other packages or objects, potentially damaging them. To prevent this, many sorting systems use sensors, cameras, and other detection equipment, combined with complex algorithms to predict whether there is a collision risk in the robotic arm's operating path. However, this increases the system's hardware cost. Summary of the Invention

[0004] In view of the defects existing in the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a package grabbing collision detection method that can avoid collision risks and does not require the addition of additional detection equipment.

[0005] To solve the above technical problems, the present invention provides a parcel grabbing collision detection method, comprising a parcel sorting system, wherein the parcel sorting system includes a grabbing robot arm and a grabbing camera for capturing a 3D overhead view of a parcel stacking area. The grabbing robot arm is provided with a grabbing suction cup for grabbing parcels at its end, and the 3D overhead view of the parcel stacking area captured by the grabbing camera includes the grabbing suction cup. The method is characterized in that the specific steps of the method are as follows:

[0006] 1) In the capture camera coordinate system, set a virtual cylinder that surrounds the capture suction cup and define the virtual cylinder as the virtual suction cup. The central axis of the virtual suction cup coincides with the central axis of the capture suction cup, and the diameter of the virtual suction cup is consistent with the maximum outer diameter of the capture suction cup.

[0007] 2) Identify all the packages to be grabbed from the image captured by the grabbing camera, select a package with the best grabbing surface from the packages to be grabbed, and set this package as the target package;

[0008] 3) Objects other than the target package in the image captured by the capture camera are defined as obstacles;

[0009] 4) Determine the operation path of the grabbing suction cup to grab the target package and judge the operation path of the grabbing suction cup;

[0010] If there is a risk obstacle among the obstacles, it indicates that there is a collision risk in the operation path of the grabbing suction cup, and then go to step 5); otherwise, go to step 6);

[0011] The method for determining whether an obstacle is a risk obstacle is as follows: if the distance between the line connecting the center points of the upper and lower ends of the virtual suction cup and the obstacle is less than the radius of the virtual suction cup when the bag grabbing suction cup moves to the position closest to the obstacle along the operation path, then the obstacle is determined to be a risk obstacle;

[0012] 5) Reselect a new package with the optimal grasping surface other than the target package from the packages to be grasped, define the new package as the new target package, and then go to step 3);

[0013] 6) Control the grabbing suction cup to grab the target package and transfer it to the subsequent sorting operation area;

[0014] 7) If the number of packages to be grabbed is 0, the package grabbing operation is terminated. Otherwise, a package with the optimal grabbing surface is selected from the packages to be grabbed, and this package is defined as the new target package, and then go to step 3).

[0015] The package grabbing collision detection method provided by the present invention sets a cylindrical virtual suction cup surrounding the package grabbing suction cup in the package grabbing camera coordinate system, and judges the collision risk by analyzing the positional relationship between the virtual suction cup and the obstacle, thereby avoiding the collision risk without adding additional detection equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of virtual suction cup settings for a package grabbing collision detection method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following is a further detailed description of an embodiment of the present invention in conjunction with the accompanying drawings, but this embodiment is not intended to limit the present invention. All similar structures and similar variations of the present invention should be included in the scope of protection of the present invention. The commas in the present invention all represent the relationship of and.

[0018] like Figure 1 As shown, an embodiment of the present invention provides a parcel grabbing collision detection method, including a parcel sorting system, wherein the parcel sorting system includes a grabbing robot arm 1 and a grabbing camera (not shown) for capturing a 3D top view of a parcel stacking area. The end of the grabbing robot arm 1 is provided with a grabbing suction cup 2 for grabbing a parcel 4. The grabbing suction cup is included in the 3D top view of the parcel stacking area captured by the grabbing camera. The specific steps of the method are as follows:

[0019] 1) In the capture camera coordinate system, set a virtual cylinder that surrounds the capture suction cup 2 and define this virtual cylinder as virtual suction cup 3. The central axis of virtual suction cup 3 coincides with the central axis of capture suction cup 2, and the diameter of the virtual suction cup is consistent with the maximum outer diameter of the capture suction cup.

[0020] For example, the bottom surface of the bag grabbing suction cup in this embodiment is square, and its maximum outer diameter is the diagonal length of its bottom surface;

[0021] 2) identifying all the packages to be grabbed 4 from the image captured by the grabbing camera, and selecting a package with the best grabbing surface from the packages to be grabbed, and setting the package as the target package;

[0022] The method of identifying a package from an image and the method of selecting a package with an optimal gripping surface are both mature technologies of existing sorting systems and will not be described in detail in this embodiment.

[0023] 3) Objects other than the target package in the image captured by the capture camera are defined as obstacles;

[0024] 4) Determine the operation path of the grabbing suction cup to grab the target package and judge the operation path of the grabbing suction cup;

[0025] If there is a risk obstacle among the obstacles, it indicates that there is a collision risk in the operation path of the grabbing suction cup, and then go to step 5); otherwise, go to step 6);

[0026] The method for determining whether an obstacle is a risk obstacle is as follows: if the distance between the line connecting the center points of the upper and lower ends of the virtual suction cup and the obstacle is less than the radius of the virtual suction cup when the bag grabbing suction cup moves to the position closest to the obstacle along the operation path, then the obstacle is determined to be a risk obstacle;

[0027] The method of determining the operating path of the bag grabbing sucker is a mature technology of the existing sorting system and will not be described in detail in this embodiment.

[0028] 5) Reselect a new package with the optimal grasping surface other than the target package from the packages to be grasped, define the new package as the new target package, and then go to step 3);

[0029] 6) Control the grabbing suction cup to grab the target package and transfer it to the subsequent sorting operation area;

[0030] 7) If the number of packages to be grabbed is 0, the package grabbing operation is terminated. Otherwise, a package with the optimal grabbing surface is selected from the packages to be grabbed, and this package is defined as the new target package, and then go to step 3).

Claims

1. A parcel grabbing collision detection method, comprising a parcel sorting system, wherein the parcel sorting system comprises a grabbing robot arm and a grabbing camera for capturing a 3D top view of a parcel stacking area. The grabbing robot arm is provided with a grabbing suction cup at the end thereof for grabbing the parcel, and the 3D top view of the parcel stacking area captured by the grabbing camera includes the grabbing suction cup. The method is characterized in that: The specific steps of this method are as follows: 1) In the capture camera coordinate system, set a virtual cylinder that surrounds the capture suction cup and define the virtual cylinder as the virtual suction cup. The central axis of the virtual suction cup coincides with the central axis of the capture suction cup, and the diameter of the virtual suction cup is consistent with the maximum outer diameter of the capture suction cup. 2) Identify all the packages to be grabbed from the image captured by the grabbing camera, select a package with the best grabbing surface from the packages to be grabbed, and set this package as the target package; 3) Objects other than the target package in the image captured by the capture camera are defined as obstacles; 4) Determine the operation path of the grabbing suction cup to grab the target package and judge the operation path of the grabbing suction cup; If there is a risk obstacle among the obstacles, it indicates that there is a collision risk in the operation path of the grabbing suction cup, and then go to step 5); otherwise, go to step 6); The method for determining whether an obstacle is a risk obstacle is as follows: if the distance between the line connecting the center points of the upper and lower ends of the virtual suction cup and the obstacle is less than the radius of the virtual suction cup when the bag grabbing suction cup moves to the position closest to the obstacle along the operation path, then the obstacle is determined to be a risk obstacle; 5) Reselect a new package with the optimal grasping surface other than the target package from the packages to be grasped, define the new package as the new target package, and then go to step 3); 6) Control the grabbing suction cup to grab the target package and transfer it to the subsequent sorting operation area; 7) If the number of packages to be grabbed is 0, the package grabbing operation is terminated. Otherwise, a package with the optimal grabbing surface is selected from the packages to be grabbed, and this package is defined as the new target package, and then go to step 3).

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