Edge position detection method, transfer position determination method, and article transfer system

Abstract

To accurately detect an edge position of articles disposed side by side.SOLUTION: An article transfer system 100 includes: a detector 140 for performing three-dimensional ranging; a rack 110 for storing multiple articles 200 by arranging them in a predetermined arrangement direction; a transfer device 130 for transferring the articles 200 between the rack 110 and itself; a conveyance apparatus 120 to which the detector 140 is mounted; and an edge position detection device 150 for detecting an edge position of the articles 200 extending along an orthogonal direction that crosses the arrangement direction at right angles. The edge position detection device 150 includes: a point group acquisition part 151 for acquiring point data in multiple places of a detection surface part 201 as a point group; a section detection part 152 for detecting a non-article section in which articles 200 do not exist in the arrangement direction from the point group; and an edge retrieval section 153 for detecting an edge position of the articles 200 by retrieving edges from a reference position in the non-article section to both the sides in the arrangement direction by using the point data.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for detecting an edge position of an article, which serves as a reference for determining a transfer position of the article, and a transfer position determining method and an article transfer system using the same. [Background technology]

[0002] For example, Patent Document 1 describes a technology in which a point cloud corresponding to the edge portions of a box-shaped object is extracted from a point cloud that indicates the three-dimensional shape of the object, and the position and orientation of each object are recognized based on the point cloud. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-247959 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional techniques, points corresponding to the edge portions of a box-like object are directly extracted from points representing the three-dimensional shape of the object, making it difficult to detect the edge positions with high accuracy.

[0005] The present invention has been made in consideration of the above problems, and relates to an edge position detection method for detecting the position of an edge of an article with high accuracy, and a transfer position determination method and article transfer system using the same. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, one edge position detection method of the present invention is an edge position detection method that uses a detector that acquires distances to objects as multiple three-dimensional point data, and detects edge positions of objects extending along a direction perpendicular to a predetermined arrangement direction on a detection surface portion of the object including a surface of the object facing the detector, for a plurality of approximately rectangular parallelepiped objects arranged in a predetermined arrangement direction. The method includes a point cloud acquisition process that acquires point data of multiple locations on the detection surface portion of the object as a point cloud, a section detection process that detects an object-free section in which no objects are present in the arrangement direction from the point cloud acquired in the point cloud acquisition process, and an edge search process that detects the edge positions of the object by searching for edges using the point data from a reference position in the middle of the object-free section in the arrangement direction toward both sides of the arrangement direction.

[0007] In order to achieve the above-mentioned object, another transfer position determination method of the present invention is an edge position detection method that uses a detector that acquires distances to articles as multiple three-dimensional point data, and detects edge positions of articles extending along an orthogonal direction perpendicular to a predetermined arrangement direction on a detection surface portion of the article including a surface of the article facing the detector, for a plurality of approximately rectangular articles arranged in a predetermined arrangement direction. The transfer position determination process includes a point cloud acquisition process that acquires point data of multiple locations on the detection surface portion of the article as a point cloud, a section detection process that detects an article-free section in which no articles are present in the arrangement direction from the point cloud acquired in the point cloud acquisition process, and an edge search process that detects the edge positions of the article by searching for edges using the point data from a reference position in the middle of the article-free section in the arrangement direction toward both sides of the arrangement direction. The transfer position determination process determines a transfer position of the article based on the edge positions of the article detected by the edge position detection method that includes:

[0008] In order to achieve the above-mentioned object, another aspect of the present invention is an item transfer system comprising: a detector that acquires a distance to an item as multiple three-dimensional point data; a rack that stores multiple approximately rectangular parallelepiped items arranged in a predetermined arrangement direction; a transfer device that transfers the items to the rack in a depth direction perpendicular to the arrangement direction; a transport device that transports the items and has the detector attached; and an edge position detection device that detects an edge position of the item extending along an orthogonal direction perpendicular to the arrangement direction on a detection surface portion including a surface of the item that faces the detector, the edge position detection device comprising: a point cloud acquisition unit that acquires point data of multiple locations on the detection surface portion of the item as a point cloud; a section detection unit that detects an item-free section in the arrangement direction from the point cloud acquired by the point cloud acquisition unit; and an edge search unit that detects the edge position of the item by searching for edges using the point data from a reference position in the middle of the item-free section in the arrangement direction toward both sides of the arrangement direction. Effect of the Invention

[0009] According to the present invention, the edge of an article can be detected with high accuracy. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view showing an article transfer system to which an edge position detection method and a transfer position determination method are applied; [Diagram 2] FIG. 2 is a perspective view showing the vicinity of a transfer device 130 of the article transfer system. [Diagram 3] FIG. 2 is a block diagram showing a functional configuration of the article transfer system. [Figure 4] 13 is a flowchart showing a process flow of a section detection unit. [Diagram 5] 11A to 11C are diagrams illustrating the processing state at each stage of the process of the section detection unit. [Figure 6] 13 is a flowchart showing a process flow of an edge searching unit. [Figure 7] 11A to 11C are diagrams illustrating the processing state at each stage of the process of an edge search unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of an edge position detection method, a transfer position determination method, and an article transfer system according to the present invention will be described with reference to the drawings. Note that the following embodiment is an example for explaining the present invention, and is not intended to limit the present invention. For example, the shapes, structures, materials, components, relative positional relationships, connection states, numerical values, mathematical expressions, contents of each step in the method, and the order of each step shown in the following embodiment are examples, and may include contents not described below. In addition, geometric expressions such as parallel and orthogonal may be used, but these expressions do not indicate mathematical strictness, and include errors, deviations, etc. that are substantially allowed. In addition, expressions such as simultaneous and identical also include a substantially allowed range.

[0012] Furthermore, the drawings are schematic diagrams in which emphasis, omissions, or ratios have been appropriately adjusted in order to explain the present invention, and the shapes, positional relationships, and ratios may differ from the actual ones.

[0013] In addition, in the following, a plurality of inventions may be collectively described as one embodiment, and some of the contents described below are described as optional components related to the present invention.

[0014] Fig. 1 is a perspective view showing an article transfer system to which the edge position detection method and the transfer position determination method are applied. Fig. 2 is a perspective view showing the vicinity of a transfer device 130 of the article transfer system. The article transfer system 100 is an apparatus that can automatically transport an article 200 that has been carried in, automatically transfer the article 200 to a storage position for the article 200, and also transport the article 200 that has been automatically transferred from the storage position, and includes a rack 110, a transport device 120, a transfer device 130, a detector 140, and an edge position detection device 150 (not shown in Figs. 1 and 2).

[0015] The article 200 to be transferred by the article transfer system 100 is not particularly limited as long as it is substantially rectangular. The term "substantially rectangular" is described as including a shape formed by six flat rectangular faces, and also including a shape having ribs, flange-like protrusions, handle-like recesses, holes, etc. Specific examples of the article 200 include cardboard boxes, containers, trays, and foldable containers.

[0016] The rack 110 is a facility for storing a plurality of substantially rectangular parallelepiped objects 200 arranged so that the detection surface 201 of the object 200 facing the area in which the transport device 120 moves is aligned along a predetermined arrangement direction (X-axis direction in the figure). In the present embodiment, the rack 110 includes a shelf 111 for holding the object 200 in a placed state, and a support 112 for supporting the shelf 111. The shelf 111 is flat, and the position for storing the object 200 is not particularly limited. The rack 110 may store only the object 200 of the same shape, or may store the object 200 of a plurality of different shapes in a mixed state. Note that the rack 110 is shown on one side as viewed in the moving direction of the transport device 120 in the figure, but the rack 110 may be arranged on both sides.

[0017] The conveying device 120 is a device that holds and conveys the article 200, and is not particularly limited as long as it is capable of being fitted with the detector 140. Examples of the conveying device 120 include an unmanned guided vehicle that holds the article 200 and travels autonomously on a floor surface, and a tracked dolly that holds the article 200 and travels along a predetermined track such as a rail. In the case of this embodiment, the conveying device 120 is a so-called stacker crane that includes a rail 121, a dolly 122 that travels on the rail 121, a mast 123 that is attached upright to the dolly 122 and moves together with the dolly 122, and a lifting platform 124 that can hold the article 200 and moves up and down along the mast 123.

[0018] The transfer device 130 is a device that transfers the article 200 between the rack 110 and the lifting platform 124 of the transport device 120, and transfers the article 200 by moving it in a depth direction (Y-axis direction in the figure) perpendicular to the arrangement direction of the articles 200 (X-axis direction in the figure) in a horizontal plane. The type of transfer device 130 is not particularly limited, and examples include a device that transfers the article 200 by clamping both opposing side surfaces of the article 200, a device that hooks a claw on the rear surface or front surface of the article 200 and transfers the article 200 while sliding it, a device that scoops up the article 200 and transfers it, etc.

[0019] In this embodiment, the transfer device 130 is attached to the lifting platform 124 of the transport device 120, and is capable of transferring the article 200 between the rack 110 and the lifting platform 124. When the racks 110 are disposed on both sides of the transport device 120, the transfer device 130 is configured to be able to transfer the article 200 to the rack 110 on either side.

[0020] The detector 140 is a sensor that acquires distances between the detector 140 and multiple points on a detection surface portion 201 of the article 200, including a surface facing the detector 140, as multiple three-dimensional point data. The type of the detector 140 is not particularly limited, and examples of the detector 140 include three-dimensional distance measuring sensors such as a LiDAR (Laser Imaging Detection and Ranging) sensor and a TOF (Time of Flight) camera.

[0021] The location where the detector 140 is attached is not particularly limited as long as it is a part of the transport device 120, but it is preferable to attach it near the location where the article 200 is transferred, for example, because the relative positional relationship between the transfer position and the article 200 can be accurately detected. In the present embodiment, the detector 140 is attached to the lifting platform 124 of the transport device 120. The number of detectors 140 provided in the article transfer system 100 is not particularly limited, but in the present embodiment, two detectors 140 are provided lined up in the arrangement direction of the articles 200. The distance between the two detectors 140 is set to include a range of distances that can acquire point data of a predetermined density or more and can detect at once the expected maximum width of the article 200 stored in the rack 110 in the arrangement direction and the area covering the gap between the adjacent articles 200 set on both sides. In the present embodiment, the detector 140 is attached to each side of the lifting platform 124 in the width direction (X-axis direction in the figure). That is, the detectors 140 are disposed on both sides of the area through which the article 200 transferred by the transfer device 130 passes. This makes it possible to accurately detect the positional relationship between the area through which the article 200 is transferred and the article 200 stored in the rack 110 nearby.

[0022] 3 is a block diagram showing the functional configuration of the article transfer system. The edge position detection device 150 is a device that detects an edge position indicating a positional relationship of an edge of the article 200 extending along a direction perpendicular to the arrangement direction (X-axis direction in the figure) on the detection surface 201 of the article 200 with respect to the transport device 120. The edge position detection device 150 includes a point cloud acquisition unit 151, a section detection unit 152, and an edge search unit 153 as processing units realized by causing a processor to execute a program. In the case of this embodiment, the edge position detection device 150 includes a transfer position determination unit 154.

[0023] The point cloud acquisition unit 151 acquires point data of a plurality of locations on the detection surface 201 of the article 200 as a point cloud from the detector 140. The data structure of the point data is not particularly limited, but includes, for example, three-dimensional data indicating a relative positional relationship with respect to the transfer device 130. In the case of this embodiment, the point data includes data of an orthogonal coordinate system including data on the arrangement direction (X-axis direction in the figure) of the article 200 on the shelf 111 of the rack 110, an orthogonal direction (Z-axis direction in the figure) perpendicular to the arrangement direction on the detection surface 201, and a depth direction (Y-axis direction in the figure) perpendicular to both the arrangement direction and the orthogonal direction.

[0024] In the present embodiment, the article transfer system 100 includes a plurality of detectors 140 arranged in the arrangement direction, and the point cloud acquisition unit 151 acquires a point cloud from each of the detectors 140. Since the adjacent detectors 140 have a part of the imaging angle of view overlapping, the point cloud acquisition unit 151 statistically processes the point data included in the overlapping area and synthesizes the point clouds of the plurality of detectors 140 into a single image. This makes it possible to process point data related to the detection surface portions 201 of the plurality of articles 200 in the arrangement direction as a single image. Note that instead of synthesizing the point clouds of the plurality of detectors 140 into a single image, it is also possible to obtain a processing result using an image corresponding to the point cloud of each detector 140, and synthesize the result.

[0025] The section detection unit 152 detects an object-free section where no object 200 exists in the arrangement direction from the point cloud acquired by the point cloud acquisition unit 151. Fig. 4 is a flowchart showing the flow of processing by the section detection unit. Fig. 5 is a diagram showing the processing state at each stage of the process of the section detection unit.

[0026] An example of the process flow of the section detection unit 152 will be described. First, the section detection unit 152 executes a trimming process to extract point data included in a predetermined area from the point cloud acquired from the point cloud acquisition unit 151 (S101, trimming process). The predetermined area is not particularly limited, but may be, for example, a strip-shaped area having a predetermined height including the center position of the minimum height (length in the orthogonal direction) of the item 200 stored in the rack 110. Specifically, point data having a value in the orthogonal direction (Z-axis direction in the figure) less than a first threshold value is excluded, and point data having a value in the orthogonal direction (Z-axis direction in the figure) greater than a second threshold value (>first threshold value) is excluded. In other words, point data in a range of not less than the first threshold value and not more than the second threshold value is extracted. Since the trimming process detects the no-item section using data in a predetermined height range, it is possible to suppress the influence of reflections from the shelf boards 111 of the rack 110 and the influence of ribs, flanges, holes, etc. provided on the surface of the item 200, and it is possible to accurately detect the no-item section. In addition, it is possible to suppress the amount of data of the point cloud and promote the processing of the next process.

[0027] Next, the section detection unit 152 projects the point cloud trimmed by the trimming process in an orthogonal direction (Z-axis direction in the figure) or in a depth direction (depth direction (transfer direction) in the present embodiment) perpendicular to both the orthogonal direction and the arrangement direction to generate a two-dimensional first projection image shown in FIG. 5(a) (S102, first projection process). Specifically, the two-dimensional first projection image is generated by excluding data in the depth direction (Y-axis direction in the figure) from each point data. Here, the section detection unit 152 may project the point cloud trimmed by the trimming process in the up-down direction to generate a two-dimensional first projection image.

[0028] Next, the section detection unit 152 executes a morphology process on the first projection image, complementing the points that existed as rough points, and modifies the data so that the part corresponding to the article 200 becomes one mass (the white part in the image in FIG. 5) as shown in FIG. 5(b) (S103, first morphology step). In the present embodiment, the section detection unit 152 executes a closing process that repeats expansion and contraction as the morphology process.

[0029] Next, the section detection unit 152 searches for an existing section that indicates the section in which the article 200 exists (S104, existing section rough search process). In the case of this embodiment, the section detection unit 152 updates the part regarded as a white mass by the first morphology process (the white part in FIG. 5(b)) by complementing the disconnected and missing parts in the vertical direction. When the existing section end search process is executed, the state becomes, for example, as shown in the image in FIG. 5(c).

[0030] Next, the section detection unit 152 compares the distance between the black parts in the horizontal direction (left and right in the drawing) in the image corresponding to the arrangement direction of the section between adjacent white block parts with a predetermined gap threshold (S105). If the distance between the black parts is equal to or less than the gap threshold (S105: Yes), the section detection unit 152 updates the part regarded as a white block by complementing the gap as shown in Fig. 5(d) (S106, gap filling step). Note that "<=" in Fig. 4 indicates less than or equal to.

[0031] Next, the section detection unit 152 identifies the white block portion updated in the gap filling process or the white block portion updated in the existence section rough search process from one end to the other end in the arrangement direction (horizontal direction in FIG. 5) (inverted triangle mark in (d) and (e) in FIG. 5) as an existence section corresponding to a section where the item 200 exists (S107, existence section identification process). In addition, it identifies sections other than the existence section, such as between adjacent existence sections, as item-free sections.

[0032] Next, the section detection unit 152 determines the middle position in the arrangement direction (horizontal direction in FIG. 5) of the object-free section as the reference position (the position of the arrow in FIG. 5(e)) (S108, reference position determination step). The criteria for determining the reference position are not particularly limited, but for example, the center position between the ends of adjacent existence sections may be determined as the reference position. In addition, when an object-free section with a length equal to or longer than a predetermined first section threshold exists (left side of FIG. 5(e)), the end of a virtual existence section (triangle mark in FIG. 5(e)) may be set at a position a predetermined distance away from the end of the existence section, and the reference position may be set between the end of the existence section and the end of the virtual existence section. Note that the distance at which the virtual existence section is set may be equal to the first section threshold. In addition, in the case of an object-free section that is not sandwiched between the ends of the existence sections and is equal to or shorter than a predetermined second section threshold (right side of FIG. 5(e)), the end of the image may be set as the reference position.

[0033] The edge search unit 153 detects the edge position of the article 200 by searching for edges using point data acquired by the point cloud acquisition unit 151 from the reference position determined by the section detection unit 152 toward both sides in the arrangement direction of the article 200. Fig. 6 is a flowchart showing the flow of processing by the edge search unit. Fig. 7 is a diagram showing the processing state at each stage of the process of the edge search unit.

[0034] Next, an example of the process flow of the edge search unit 153 will be described. First, the edge search unit 153 projects the point cloud acquired by the point cloud acquisition unit 151 in the orthogonal direction (height direction) to generate a two-dimensional second projection image shown in FIG. 7(a) (S201, second projection step). Note that the edge search unit 153 may project the point cloud acquired by the point cloud acquisition unit 151 in the depth direction to generate a two-dimensional second projection image, and perform the following process. Specifically, the two-dimensional second projection image is generated by excluding data in the height direction (Z-axis direction in the figure) from each point data. Note that the point data after trimming by the section detection unit 152 in the trimming step may be used.

[0035] Next, the edge search unit 153 executes a morphology process on the second projection image to complement the points data that existed as rough points, and changes the data so that the part corresponding to the article 200 becomes a line (the white part in the image in FIG. 7) as shown in FIG. 7(b) (S202, second morphology step). In the case of this embodiment, the edge search unit 153, like the section detection unit 152, executes a closing process of repeating expansion and contraction as the morphology process.

[0036] Next, the edge search unit 153 removes noise from the point data that has been subjected to the morphology process (S203, noise processing step). In the case of this embodiment, the edge search unit 153 performs a labeling process to distinguish a group of point data. Then, a group of point data that is equal to or shorter than a predetermined length threshold is deleted. This results in an image as shown in FIG. 7(c).

[0037] Next, the edge search unit 153 extracts points that are candidates for edges (S204, edge candidate point extraction step). Although the method of extracting edge candidate points is not particularly limited, in the present embodiment, for a group of linear parts obtained by the second morphology step, a part corresponding to an edge in the point data on the side closer to the detector 140 in the depth direction (point data on the lower side in the drawing) is extracted as an edge candidate point.

[0038] Next, the edge search unit 153 searches for point data from the reference position determined by the section detection unit 152 toward both sides of the arrangement direction of the article 200 based on the point data extracted in the edge candidate point extraction process, and detects the position of the edge along the perpendicular direction of the article 200 (white arrow in FIG. 7E) (S205, edge position detection process). Although the specific method of detecting the edge position is not limited, in the present embodiment, the edge position is detected by the following method. That is, in a group of linear parts in FIG. 7D, which is the second projection image, the slope which is the distance in the depth direction (up and down direction in FIG. 7D) relative to the distance in the arrangement direction between two point data aligned (for example, adjacent) in the arrangement direction (horizontal direction in FIG. 7D), or the slope which is the distance in the arrangement direction relative to the distance in the depth direction between two point data is sequentially calculated in the direction away from the reference position, and when the difference in slope between the pair of adjacent point data becomes equal to or less than a predetermined difference threshold, the position in the arrangement direction of the point data closest to the reference position of the pair is detected as the edge position. In addition, the edge search unit 153 searches for point data from the reference position toward both sides in the arrangement direction, but the side on which no point data can be detected even after searching a specified distance, or the side on which no point data can be detected and the edge of the image is reached, may be treated as having no edge position.

[0039] As a result of the above, sequences of point data that change significantly can be excluded from candidates for edge positions, and the ends of stable point data can be detected as edge positions, making it possible to accurately detect edge positions corresponding to the edges of the actual article 200.

[0040] The transfer position determination unit 154 executes a transfer position determination step of determining a transfer position where the conveying device 120 stops with respect to the rack 110 and transfers the item 200 based on the edge position of the item 200 detected by the edge search unit 153. Specifically, since the edge position detected by the edge search unit 153 indicates the relative positional relationship of the item 200 stored in the rack 110 with respect to the conveying device 120, the transfer position determination unit 154 determines a stop position in the arrangement direction of the conveying device 120 so that the transfer device 130 can be inserted into an item-free section between adjacent items 200 based on the detected edge position and the item 200 can be transferred from the rack 110 to the conveying device 120. In addition, when the item 200 is not stored next to the item 200 stored in the rack 110, the transfer position determination unit 154 determines a stop position of the conveying device 120 so that the item 200 can be stored at a predetermined distance from the edge position of the stored item 200. The transport device 120 acquires the determined stop position, compares it with the current position of the transport device 120, and if there is a positional deviation, moves in the arrangement direction to match the stop position.

[0041] According to the article transfer system 100 of the above embodiment, by performing two-stage processing, namely, a process of detecting an article-free section, which is a section between adjacent articles 200 where no articles 200 exist, and separating and roughly positioning the articles 200 from each other, and a process of determining the detailed edge positions of the articles 200 based on the article-free section, it is possible to detect the edge positions in the arrangement direction of each of a plurality of articles 200 arranged in the arrangement direction with high accuracy. This makes it possible to store the articles 200 in the rack 110 in a high-density state.

[0042] Furthermore, by identifying an object-free section and determining a reference position using a first projection image in which the three-dimensional point data obtained from detector 140 is converted into two-dimensional data projected in the depth direction (transfer direction), and by searching in detail for the edge position based on the determined reference position and a second projection image projected in a direction perpendicular to the projection direction of the first projection image (orthogonal direction), it becomes possible to accurately detect the edge position of object 200 even when object 200 is stored with detection surface 201 tilted relative to the arrangement direction, or when object 200 has ribs, flanges, holes, etc. provided on its outer surface.

[0043] Furthermore, by performing morphological processing, noise processing, etc. suitable for edge detection on the first projection image and the second projection image, it is possible to properly search for the range in the first projection image in which the cluster of point data corresponding to the item 200 exists, and it is possible to detect the edge position of the item 200 while suppressing errors based on the range in the second projection image in which the cluster of point data corresponding to the searched item 200 exists.

[0044] The present invention is not limited to the above-described embodiment. For example, the components described in this specification may be combined in any manner, or some of the components may be removed to create another embodiment of the present invention. In addition, the present invention also includes modifications that are made to the above-described embodiment by those skilled in the art without departing from the spirit of the present invention, i.e., the meaning of the words in the claims.

[0045] For example, in the edge detection process in the embodiment, the edge position is detected based on a pair of point data in which the change in slope, which is the distance in the depth direction (up and down direction in Figure 7) relative to the distance in the arrangement direction between two adjacent pairs of point data in the arrangement direction, is stable, but the edge position may also be detected based on the slope, which is the distance in the arrangement direction relative to the distance in the depth direction between the pairs of point data.

[0046] Although an example has been given of a case in which multiple detectors 140 are provided, it is also possible to provide a single detector 140 that can simultaneously detect an area that is the sum of the width of the central item 200 of three items 200 lined up in succession on the shelf 111 of the rack 110 and the widths of the item-free sections on both sides.

[0047] Furthermore, although the transport device 120 that freely transports the article 200 within a vertical plane has been exemplified, the transport device 120 may be a rail-driven or railless transport vehicle that transports the article 200 within a horizontal plane.

[0048] Furthermore, although the rack 110 is exemplified as being capable of storing the items 200 two-dimensionally in the horizontal and vertical directions, the rack 110 may be capable of storing the items 200 one-dimensionally along the direction in which the transport vehicle travels.

[0049] Furthermore, it is possible to omit steps such as trimming the point cloud and removing noise. [Industrial Applicability]

[0050] INDUSTRIAL APPLICABILITY The present invention can be used in automated warehouses, logistics centers, factory facilities, and the like, where articles are transported by a transport device and the articles are transferred between racks and the transport device. [Explanation of symbols]

[0051] 100 Goods Transfer System 110 Rack 111 Shelf 112 Post 120 Transport Equipment 121 Rail 122 Trolley 123 Mast 124 Lifting platform 130 Transfer equipment 140 Detector 150 Edge position detection device 151 Point cloud acquisition part 152 Section detection unit 153 Edge Search Unit 154 Transfer position determination unit 200 items 201 facial expression

Claims

1. 1. An edge position detection method for detecting an edge position of a plurality of substantially rectangular parallelepiped objects arranged in a predetermined arrangement direction, the method using a detector that acquires distances to the objects as a plurality of three-dimensional point data, the edge position detecting method comprising the steps of: detecting an edge position of the object extending along a direction perpendicular to the arrangement direction on a detection surface portion including a surface of the object facing the detector, the detection surface portion including the surface of the object facing the detector, the edge position detecting method comprising the steps of: a point cloud acquisition step of acquiring point data of a plurality of points on a detection surface of the article as a point cloud; a section detection step of detecting an object-free section in which no object is present in the arrangement direction from the point cloud acquired in the point cloud acquisition step; an edge searching step of detecting an edge position of an article by searching for an edge using the point data from a reference position in the article-free section toward both sides in the arrangement direction; The edge location detection method includes:

2. In the section detection step, A first projection image is generated by projecting the point cloud in a depth direction perpendicular to the orthogonal direction or perpendicular to both the orthogonal direction and the arrangement direction, and an object-free section in which no object is present is detected based on the first projection image.

2. The edge position detection method according to claim 1.

3. In the section detection step, The first projection image is subjected to morphology processing, and an object-existing section in the arrangement direction is identified based on the first projection image after the morphology processing, and a section between adjacent object-existing sections is identified as an object-free section.

3. The edge position detection method according to claim 2.

4. In the edge searching step, projecting the point cloud in the orthogonal direction to generate a second projection image; and searching for edges based on the second projection image. The edge position detection method according to claim 1 .

5. In the edge searching step, An edge position is detected based on a gradient that is a distance in the orthogonal direction relative to the distance in the arrangement direction between two point data included in the second projection image, or a distance in a depth direction perpendicular to both the orthogonal direction and the arrangement direction, or a gradient that is a distance in the arrangement direction relative to the distance in the depth direction between two point data.

5. The edge position detection method according to claim 4.

6. The edge position detection method according to any one of claims 1 to 5, further comprising a transfer position determination step of determining a transfer position of the article based on the edge position of the article detected by the edge position detection method according to any one of claims 1 to 5. Transfer position determination method.

7. A detector that acquires a distance to an article as three-dimensional multiple point data; A rack for storing a plurality of substantially rectangular parallelepiped-shaped articles arranged in a predetermined arrangement direction; A transfer device that transfers an article to the rack in a depth direction perpendicular to the arrangement direction; a conveying device for conveying an article and having the detector mounted thereon; an edge position detection device that detects an edge position of an article extending along a direction perpendicular to the arrangement direction on a detection surface portion of the article that includes a surface facing the detector, The edge position detection device includes: a point cloud acquisition unit that acquires point data of a plurality of points on a detection surface of an article as a point cloud; From the point cloud acquired by the point cloud acquisition unit, it is determined that no article exists in the arrangement direction. A section detection unit for detecting an object-free section; an edge search unit that detects an edge position of an article by searching for an edge using the point data from a reference position in the no-article section toward both sides in the arrangement direction; An article transfer system comprising:

Images