JPH08225155A - Palletizing method - Google Patents

Abstract

PURPOSE: To provide a palletizing method which can increase stacking efficiency while a palletizing robot and an article held by the robot are made not to collide with and interfere with a previously stacked article at the time of being stacked. CONSTITUTION: This palletizing method comprises the step of determining the stacking proposed position of an article W so that a palletizing robot 1 and the article W held by a holding device 12 of the robot 1 are made not to collide with and interfere with a previously stacked article at the time of being stacked and the step of distinguishing a stackable position on the back side in the direction of being stacked from the proposed position to dispose the article W. The extraction of the proposed point being the stacking proposed position is performed on the basis of edge information changed at every time when the article W is disposed. In the edge information, it is so arranged that the edge does not exist on the back side (left side and back side) in the direction of being stacked from the disposed article. Also, the stacking proposed position which is determined to be unable to be stacked when the stackable position is distinguished can become the stacking proposed position for the succeeding article W.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for palletizing a plurality of articles on a pallet by a palletizing robot, and more particularly to a palletizing method capable of automatically generating an optimum article stacking pattern.

[0002]

2. Description of the Related Art In distribution centers and the like, palletizing robots have been put into practical use that automatically palletize the number of ordered items on a pallet plane in order to send them to each customer in response to an order. This palletizing robot changes the order and / or the direction of each article and sequentially stacks a plurality of articles on a pallet according to a pattern selected from a plurality of stacking patterns generated.
FIG. 5 is a plan view of a pallet showing an example of a conventional packing pattern. After the articles W1 to W3 are stacked in the palletizing robot in the order from the inner side and the left side of the pallet (first row), the robot and the article held by the robot at the time of stacking have already been placed. Goods (hereinafter,
It is called "preliminary article". ) In order to prevent collision and interference with W1 to W3, among the articles W1 to W3, the article W4 having the largest size in the Y direction is used as a reference.
Are aligned and stacked on the line Y = y2 (second row).

[0003]

Due to the structure of the palletizing robot, it is not possible to place an article at a position deeper than the preceding article in front of the palletizing robot, or to place the article so as to fit the article snugly between the articles. Therefore, in order to efficiently pack the articles on the pallet, it is necessary to pack the articles from the back in the stacking direction. In the example shown in FIG. 5, articles are stacked on the pallet 3 by the palletizing robot from diagonally right front to diagonally left rear. However, even if the articles W6 are stacked farther, the pre-positioned articles W1 to
Although there is no problem of collision / interference with 5, the article W
Like W4 and W5, they are stacked on the line Y = y2. In this way, in the conventional method, although there is no problem of collision / interference even if it is packed further in the back, it may be stacked in line with the pre-positioned article, so that high packing efficiency (flat area of pallet) In some cases, it was not possible to obtain the ratio of the bottom area of all articles on the pallet to the above. If the loading efficiency becomes low, the number of pallets required will increase, the efficiency at the time of delivery will deteriorate, and the possibility of a load collapse will increase.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent a palletizing robot and an article held by the robot from colliding with or interfering with a preceding article at the time of loading. It is to provide a palletizing method capable of increasing efficiency.

[0005]

In order to achieve the above object, an invention according to claim 1 is a method of loading a plurality of articles on a pallet by a palletizing robot, wherein the robot and the robot are used at the time of loading. The process of deciding the placement candidate position of the item so that the item held by the product does not collide with or interfere with the preceding item, and from this candidate position, the possible placement position that is deeper in the stacking direction is determined. And a step of arranging the article to provide a palletizing method.

According to the second aspect of the present invention, the placement candidate position is determined based on the edge information that is changed every time the articles are placed, and the edge information is located farther in the stacking direction than the placed articles in the edge information. Shall have no edges.

According to the third aspect of the present invention, the placement candidate position that is determined to be unmountable when determining the placement possible position can be the placement candidate position for subsequent articles. .

[0008]

According to the first aspect of the present invention, the placing candidate positions of the articles are determined so that the palletizing robot and the articles held by the robot do not collide with or interfere with the preceding articles during the packing. The articles are arranged by discriminating the possible mounting position that is deeper in the stacking direction from the positions.
Therefore, it is possible to improve the stowage efficiency while preventing the palletizing robot and the articles held by the robot from colliding with or interfering with the preceding articles during the stowing.

According to the second aspect of the present invention, the placement candidate position is determined based on the edge information that is changed every time the articles are placed, and the edge information is located farther in the stacking direction than the placed articles. Since there is no edge in the item, you can easily place items,
It is possible to increase the packing efficiency while preventing the palletizing robot and the articles held by the robot from colliding with or interfering with the pre-positioned articles during the loading.

According to the third aspect of the present invention, the placement candidate positions which are determined to be unmountable when the mountable position is determined are:
Since it is possible to be the placement candidate position for the subsequent articles, the loading efficiency can be further increased by arranging the subsequent articles of different sizes at the same placement candidate position.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. However, it goes without saying that the present invention is not limited to the embodiments and can be appropriately modified within the scope of the gist of the present invention. 1 is a block diagram showing a main part of a control structure of a system to which an embodiment of the present invention is applied, FIG. 2 is a plan view showing an example of a pattern generated in a pattern generation process,
FIG. 3 is a flow chart showing the processing operation in the pattern generation unit, and FIG. 4 is a plan view showing the palletizing robot.

The palletizing robot 1 depalletizes an article W from a single pallet 2 in which a plurality of articles of the same type are stacked and palletizes it on an empty shipping pallet 3. At the tip of the arm 11 of the palletizing robot 1, a gripping device 12 for sucking the upper surface of the article W and gripping the article W is attached. The gripping device 12 is rotatable about a vertical axis with respect to the arm 11, and the arm 11 is extendable and retractable, and is rotatable about the vertical axis and movable up and down with respect to the robot body. With such a configuration, the palletizing robot 1 can depalletize and palletize the article W at any position, height, and orientation. Incidentally, the palletizing robot may palletize the articles one by one on the pallet as in this embodiment, or may palletize the articles stacked in a rod shape on the pallet all at once.

In FIG. 1, order data, such as the type, quantity, order source, order area, etc. of an item to be ordered, is input by the order input device 4. The system controller 5 receives the order data and gives a command to each device belonging to the system. For example, the transfer command is transmitted to the robot controller 13 mounted on the palletizing robot 1 or the crane controller 6 that controls the stacker crane of the automatic warehouse.

The pattern generating section 51, the pattern comparing section 52, the pattern selecting section 53, and the pattern storing section 54 are involved in the palletizing. The pattern generation unit 51 includes an edge information storage unit 55 that stores edge information. When the order input data is transmitted from the order input device 4 to the system controller 5, the pattern generation unit 51 determines, based on the order data and the edge information stored in the edge information 55,
A plurality of patterns for stacking a plurality of articles are generated. Therefore, the pattern generation unit 51 has necessary data such as sizes of various articles and pallets. The pattern storage unit 54 stores the plurality of patterns generated by the pattern generation unit 51, the pattern comparison unit 52 compares the plurality of patterns stored in the pattern storage unit 54, and the pattern selection unit 53 performs the pattern comparison. One pattern is selected based on the result, read from the pattern storage unit 54, and a command is given to the robot controller 13.

In the pattern generator 51, the stacking pattern is generated according to a certain rule. This is the arm 1 of the palletizing robot 1 when loading the articles W.
1 or the article W gripped by the gripping device 12 is the pallet 3
This is because the article W cannot be placed on a flat plane that is closer to the left side and the inner side of the pre-placement article W because it collides and interferes with the above-mentioned pre-placement article W. Therefore, the articles W are placed on the palletizing robot 1 in order from the left side and the rear side. Figure 2
In the example, W1, W2 ... W6 are stacked in this order.

The flow of the processing operation in the pattern generator 51 will be described with reference to FIG. When the order data is input, first, solution candidate points on which the article W is placed are extracted (S1). Extraction of solution candidate points is performed according to a certain rule based on the edge information. Next, it is determined whether or not the article W can be placed at this solution candidate point (S
2) If the article W can be placed, the article W is placed with its solution candidate point at a corner (hereinafter, simply referred to as “placement”) and the edge information is changed (S3). And the next article W
It is determined whether there is any (S4), and if there is, the process returns to S1 to extract the solution candidate points for the next article W, and then the same process as above is performed. If there is no next article W, the process ends.
In S2, when the article W cannot be placed on the extracted solution candidate point, it is determined whether or not there is a next solution candidate point (S5). If there is, the process returns to S1 to extract the next solution candidate point. rear,
The same process as above is performed. If there is no next solution candidate point, the process ends and the process for the next palette is performed.

Next, the pattern generation process based on the change of the edge information will be specifically described with reference to FIG. The plane of the palette is represented by XY coordinates, the horizontal direction is X, the depth direction is Y, and the upper left corner on the palette 3 is (0, 0). The size of the pallet 3 is 18 in the X direction and 11 in the Y direction. First, the first article W1 is the pallet 3
It is arranged at the solution candidate point P1 at the coordinate (0, 0) that is the leftmost and the farthest position on the top. Then, the edge information is changed based on the area occupied by the article W1 (size 7 in the X direction, size 4 in the Y direction). At this time, two edges in the Y direction are a line of Y = 0 (X = 7 to 18) and a line of Y = 4 (X = 0 to 7), and an edge in the X direction is a line of X = 0 ( Y = 4 to 11) and X = 7 lines (Y = 0 to 4). Based on this, the solution candidate point P2 (7,0) for the next article W2 is extracted. It should be noted that the solution candidate points are extracted from those closer to the right side of the article W placed last time.

Then, the article W2 is defined as a solution candidate point P2 (7,
It is determined whether or not it can be placed (hereinafter simply referred to as “placement”) with its corner aligned with 0). The size 5 of the article W2 in the X direction is from the size 18 of the pallet 3 in the X direction to the article W.
Since the length is smaller than the length obtained by subtracting the size 7 of 1 in the X direction, the article W2 placed at the solution candidate point P2 does not protrude from the pallet 3. Therefore, it is determined that the article W2 can be placed, the article W2 is placed at the solution candidate point P2, and the edge information is changed. At this time, the edge in the edge information is a line of X = 0 (Y = 5 to 11) and a line of Y = 5 (X = 0.
.About.12) and the line of Y = 0 (X = 12 to 18). Since the size 5 in the Y direction of the article W2 is larger than the size 4 in the Y direction of the article W1, the edge in the Y direction in the range of X = 0 to 7 is not the line Y = 4 but the line Y = 5. Become. That is, in the edge information, there is no edge in the depth (leftward and depth) with respect to the stacking direction with respect to the arranged articles W. Then, based on this edge information, the solution candidate point P3 (1
2, 0) are extracted, and after the placement possibility is determined, the solution candidate point P3
The edge information is changed while the article W3 is placed in the.

Similarly, a solution candidate point P4 for the next article W4
a (17,0) is extracted, and it is determined whether or not it can be placed.
When the article W4 (size 6 in the X direction) is placed on the solution candidate point P4a, the article W4 protrudes from the pallet 3, so it is determined that the article W4 cannot be placed, and (0, 5) is extracted as the next solution candidate point P4. . Based on the edge information after placing the article W3,
In addition to the solution candidate point P4a, 2 of (0, 5) and (12, 2)
Although points can be solution candidate points, they are first extracted from solution candidate points (0, 5) with a small X coordinate. After the placement determination, the article W4 is placed at the solution candidate point P4 and the edge information is changed. Since the edge including the solution candidate point P4a determined to be unmountable (Y = 0 line of X = 17 to 18 and X = 17 of Y = 0 to 2) is continuously stored as edge information, The solution candidate point P4a can be a solution candidate point even for the article after the article W5.

Similarly, the next article W5 is the solution candidate point P5 (6,
5) and the edge information is changed. Since there is no edge in the back side (left side and back side) with respect to the stacking direction of the arranged articles W, the line of Y = 2 (X = 12 to 13), the line of X = 12. Lines (Y = 2 to 5) and Y = 5 (X = 12 to 13) are not regarded as edges. Therefore, the edge in the range of X = 12 to 14 is the line of Y = 8 (X = 12 to 13), X = 1.
3 lines (Y = 2 to 8) and Y = 2 lines (X = 13 to 1)
4).

Similarly, the next item W6 is the solution candidate point P6 (1
3), the edge information is changed. Then, similarly, it is determined whether or not the next article W (size in X direction> 2, size in Y direction> 4) can be placed on the solution candidate point P7a (16,2) extracted based on the edge information. Starting from the solution candidate point P7a, the other four solution candidate points (17, 0) extracted based on the edge information,
Since it is determined that all of (0, 9), (6, 8), and (13, 7) cannot be placed, the article W previously placed
The process for this pallet 3 is finished with 6 as the final article. Similarly, the stacking patterns are generated for the plurality of pallets 3 until there are no more articles W to be arranged.

The pattern generated as described above is
It is stored in the pattern storage unit 54. After that, change the order and / or orientation of the articles to generate a certain number of patterns, evaluate and compare each pattern with a predetermined evaluation method considering the loading efficiency, etc., and temporarily select an appropriate one. The process of making a change to the temporarily selected pattern and further evaluating and comparing is repeated, and the finally recognized pattern is selected. Then, the palletizing robot 1 is used to stack the articles W on the pallets 3 according to the selected optimum pattern.

In the present specification, "back" is a direction far from the palletizing robot 1, "left and right" is both directions perpendicular to the back direction, and "rear with respect to the stacking direction" means
This is the moving direction of the articles near the packing position during packing. That is, in the present embodiment, the arm 11 of the palletizing robot 1 is rotated counterclockwise in FIG. 4 for stacking, so that the “packing direction” is a direction from diagonally right front to diagonally left rear. Therefore, "rearward with respect to the stacking direction" means leftward and rearward, and articles cannot be stacked on a plane that is lower leftward and lower than the preceding article. Incidentally, the difference in the stacking direction depending on the type of the palletizing robot can be dealt with by appropriately changing the rule when changing the edge information.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a control structure of a system to which an embodiment of the present invention is applied.

FIG. 2 is a plan view showing an example of a pattern generated in a pattern generation process.

FIG. 3 is a flowchart showing a processing operation in a pattern generation unit.

FIG. 4 is a plan view showing a palletizing robot.

FIG. 5 is a plan view of a pallet showing an example of a conventional packing pattern.

[Explanation of symbols]

 1 Palletizing Robot 2 Single Pallet 3 Pallet 4 Order Input Device 5 System Controller 6 Crane Controller 13 Robot Controller 51 Pattern Generation Unit 52 Pattern Comparison Unit 53 Pattern Selection Unit 54 Pattern Storage Unit 55 Edge Information Storage Unit

Claims (3)

[Claims] 1. A method of stacking a plurality of articles on a pallet by a palletizing robot, wherein the articles held by the robot and the robot do not collide with or interfere with a preceding article during the loading. A palletizing method including a step of deciding a placement candidate position and a step of deciding a placement possible position that is deeper in the stacking direction from the candidate positions and placing an article. 2. The placement candidate position is determined based on edge information that is changed each time an article is placed, and in the edge information, there is no edge deeper in the stacking direction than the placed articles. The palletizing method according to claim 1, wherein 3. The palletizing method according to claim 1, wherein the placement candidate position determined to be unplaceable when determining the placement possible position can be the placement candidate position for the subsequent articles.