Method, system and computer program product for moving storage container

Abstract

The present invention relates to a system, a method, and a computer program product for moving a storage container. The method includes assigning a task to a container handling vehicle to retrieve storage containers (106) from a storage column and to deliver the storage containers (106) to a port area (510) of an access station. The container handling vehicle is instructed to retrieve the storage containers from the storage column (106). A virtual buffer position (610) is determined on the track system between the storage column and the port area (510). The container handling vehicle is instructed to move the storage container (106) toward a virtual cushioning position (610) on the track system. Data of a current position of the storage container (106) on the track system and a current availability of the access station is repeatedly received. Instructing the container handling vehicle to move the storage container (106) to the row (119, 120) of port areas (510) when the current position of the storage container (106) is different from the virtual buffer position (610) and the row (119, 120) of port areas (510) is available; and instructing the container handling vehicle to dispense the storage containers (106) into the column of port areas (510).

Description

Technical Field

[0001] The present invention relates to an automated storage and retrieval system for storing and retrieving containers, and more particularly, to a method, system, and computer program product for moving storage containers. Background Art

[0002] Figure 1 There is disclosed a prior art automated storage and retrieval system 1 having a frame structure 100, and Figure 2 、 Figure 3 and Figure 4 There are disclosed three different prior art container handling vehicles 201, 301, 401 suitable for operating on such a system 1.

[0003] The frame structure 100 includes upright members 102 and a storage volume that includes storage rows 105 arranged in rows between the upright members 102. In these storage rows 105, storage containers 106 (also referred to as bins) are stacked one on top of another to form stacks 107. The members 102 can typically be made of metal (such as extruded aluminum profiles).

[0004] The frame structure 100 of the automated storage and retrieval system 1 includes a track system 108 disposed across the top of the frame structure 100 on which a plurality of container handling vehicles 201, 301, 401 can operate to lift storage containers 106 from the storage rows 105 and lower the storage containers 106 into the storage rows, and also to transport the storage containers 106 above the storage rows 105. The track system 108 includes: a first set of parallel tracks 110 arranged to guide the container handling vehicles 201, 301, 401 across the top of the frame structure 100 in a first direction X; and a second set of parallel tracks 111 arranged perpendicular to the first set of tracks 110 to guide the container handling vehicles 201, 301, 401 in a second direction Y perpendicular to the first direction X. The containers 106 stored in the rows 105 are accessed by the container handling vehicles 201, 301, 401 through access openings 112 in the track system 108. The container handling vehicles 201, 301, 401 can move laterally above the storage rows 105, i.e., laterally in a plane parallel to the horizontal X - Y plane.

[0005] The upright members 102 of the frame structure 100 can be used to guide the storage containers during lifting the containers from the rows 105 and lowering the containers into the rows. The stacks 107 of the containers 106 are typically self - supporting.

[0006] Each of the prior art container handling vehicles 201, 301, 401 includes a vehicle body 201a, 301a, 401a and a first set of wheels 201b, 301b, 401b and a second set of wheels 201c, 301c, 401c, and these two sets of wheels enable the container handling vehicles 201, 301, 401 to move laterally in the X direction and the Y direction respectively. In Figure 2 , Figure 3 and Figure 4 , two wheels in each set of wheels are fully visible. The first set of wheels 201b, 301b, 401b are arranged to engage with two adjacent tracks in the first set of tracks 110, and the second set of wheels 201c, 301c, 401c are arranged to engage with two adjacent tracks in the second set of tracks 111. At least one set of the two sets of wheels 201b, 201c, 301b, 301c, 401b, 401c can be lifted and lowered, so that the first set of wheels 201b, 301b, 401b and / or the second set of wheels 201c, 301c, 401c can engage with the corresponding set of tracks 110, 111 at any time.

[0007] Each of the prior art container handling vehicles 201, 301, 401 further includes a lifting device for vertically transporting the storage container 106, for example, raising the storage container 106 from the storage row 105 and lowering the storage container 106 into the storage row. The lifting device includes one or more clamping / engaging devices adapted to engage with the storage container 106, and the clamping / engaging device can be lowered from the vehicles 201, 301, 401, so that the position of the clamping / engaging device relative to the vehicles 201, 301, 401 can be adjusted in a third direction Z orthogonal to the first direction X and the second direction Y. The components of the clamping device of the container handling vehicles 301, 401 are shown in Figure 3 and Figure 4 and are denoted by reference numerals 304, 404. In Figure 2 , the clamping device of the container handling device 201 is located inside the vehicle body 201a and is thus not shown.

[0008] Conventionally and also for the purposes of this application, Z = 1 identifies the uppermost layer available for storing containers below the tracks 110, 111, that is, the layer immediately below the track system 108, Z = 2 identifies the second layer below the track system 108, Z = 3 identifies the third layer, etc. In the exemplary prior art disclosed in Figure 1 , Z = 8 identifies the bottom layer of the lowermost side of the storage container. Similarly, X = 1…n and Y = 1…n identify the positions of each storage row 105 in the horizontal plane. Thus, as an example and using the Cartesian coordinate system X, Y, Z shown in Figure 1 , it can be said that in Figure 1The storage container labeled 106’ in the figure occupies the storage position of X = 17, Y = 1, and Z = 6. It can be said that the container handling vehicles 201, 301, and 401 travel in the layer where Z = 0, and each storage column 105 can be identified by its X coordinate and Y coordinate. Therefore, Figure 1 The storage container extending above the rail system 108 shown in the figure is also referred to as being arranged in the layer where Z = 0.

[0009] The storage volume part of the frame structure 100 is generally referred to as the grid 104, where the possible storage positions within this grid are called storage units. Each storage column can be identified by the positions in the X direction and Y direction, while each storage unit can be identified by the container numbers in the X direction, Y direction, and Z direction.

[0010] Each prior art container handling vehicle 201, 301, and 401 includes a storage compartment or storage space for receiving and loading the storage container 106 when transporting the storage container 106 across the rail system 108. The storage space can include a cavity arranged inside the vehicle bodies 201a and 401a, as Figure 2 and Figure 4 shown in the figure and described, for example, in WO2015 / 193278A1 and WO2019 / 206487A1, the contents of these applications are incorporated herein by reference.

[0011] Figure 3 An alternative configuration of the container handling vehicle 301 with a cantilever structure is shown. This vehicle is described in detail, for example, in NO317366, and the content of this application is also incorporated herein by reference.

[0012] Figure 2 The occupied area of the cavity-type container handling vehicle 201 shown in the figure can cover an area whose dimensions in the X direction and Y direction are approximately equal to the lateral range of the storage column 105, as described, for example, in WO2015 / 193278A1, the content of this application is incorporated herein by reference. The term "lateral" used herein can refer to "horizontal".

[0013] Alternatively, the occupied area of the cavity-type container handling vehicle 401 can be larger than the lateral area defined by the storage column 105, as Figure 1 and Figure 4 shown in the figure and disclosed, for example, in WO2014 / 090684A1 or WO2019 / 206487A1.

[0014] The track system 108 generally includes tracks having grooves in which the wheels of the vehicle travel. Alternatively, the tracks can include upwardly projecting elements, where the wheels of the vehicle include flanges to prevent derailment. These grooves and upwardly projecting elements are collectively referred to as guideways. Each track can include one guideway, or each of the tracks 110, 111 can include two parallel guideways. In other track systems 108, each track in one direction (e.g., the X direction) can include one guideway, and each track in another perpendicular direction (e.g., the Y direction) can include two guideways. Each of the tracks 110, 111 can also include two guideway members fastened together, with each guideway member providing one guideway for a pair of guideways of each track.

[0015] WO2018 / 146304A1 (the content of which is incorporated herein by reference) shows a typical configuration of a track system 108 that includes tracks and parallel guideways in both the X direction and the Y direction.

[0016] In the frame structure 100, most of the columns 105 are storage columns 105, i.e., columns 105 in which storage containers 106 are stored in the form of stacks 107. However, some of the columns 105 can have other purposes. In Figure 1 this regard, columns 119 and 120 are such dedicated columns used by the container handling vehicles 201, 301, 401 to unload and / or pick up the storage containers 106, such that the storage containers can be transported to an access station (not shown) where the storage containers 106 can be accessed from outside the frame structure 100, or removed from or moved into the frame structure 100. In the art, such locations are generally referred to as "ports", and the columns where the ports are located can be referred to as "port columns" 119, 120. The transportation to the access station can be in any direction (i.e., horizontal, inclined, and / or vertical). For example, the storage container 106 can be placed in a random column or a dedicated column 105 within the frame structure 100, and then picked up by any of the container handling vehicles and transported to the port columns 119, 120 for further transportation to the access station. The transportation from the port to the access station may need to move along various different directions by means of, for example, a delivery vehicle, a cart, or other transportation lines. Note that the term "inclined" means that the transportation of the storage container 106 has a generally transport orientation between horizontal and vertical.

[0017] In Figure 1Among them, the first port column 119 can be, for example, a dedicated offloading port column at which the container handling vehicles 201, 301, 401 can offload the storage containers 106 to be transported to the access station or transfer station, and the second port column 120 can be a dedicated pickup port column at which the container handling vehicles 201, 301, 401 can pick up the storage containers 106 that have been transported from the access station or transfer station.

[0018] The access station can generally be a picking station or a replenishment station at which product items are removed from or placed into the storage containers 106. In the picking station or replenishment station, the storage containers 106 are generally not removed from the automated storage and retrieval system 1 but are returned to the frame structure 100 again after access. The ports can also be used to transfer the storage containers to another storage facility (e.g., to another frame structure or another automated storage and retrieval system), to a transport vehicle (e.g., a train or a truck), or to a production facility.

[0019] A conveying system including conveyors is generally used to transport the storage containers between the port columns 119, 120 and the access station.

[0020] If the port columns 119, 120 and the access station are at different levels, the conveying system can include a lifting device having a vertical component for vertically transporting the storage containers 106 between the port columns 119, 120 and the access station.

[0021] The conveying system can be arranged to transfer the storage containers 106 between different frame structures, as described, for example, in WO2014 / 075937A1, the content of which is incorporated herein by reference.

[0022] When it is necessary to access the storage in Figure 1When storing container 106 in one of the multiple columns 105 disclosed, it is indicated that one of the multiple container handling vehicles 201, 301, 401 picks up the target storage container from the position of the target storage container 106 and transports the target storage container to the unloading port column 119. This operation involves: moving the container handling vehicles 201, 301, 401 to a position above the storage column 105 where the target storage container 106 is located; using the lifting device (not shown) of the container handling vehicles 201, 301, 401 to pick up the storage container 106 from the storage column 105; and transporting the storage container 106 to the unloading port column 119. If the target storage container 106 is deep within the stack 107, i.e., there is one or more other storage containers 106 above the target storage container 106, this operation also involves: temporarily moving the storage containers located above before lifting the target storage container 106 from the storage column 105. This step (sometimes referred to in the art as "digging") can be performed using the same container handling vehicle that will subsequently transport the target storage container to the unloading port column 119, or using one or more other cooperative container handling vehicles. Alternatively or additionally, the automated storage and retrieval system 1 can have container handling vehicles 201, 301, 401 dedicated to the task of temporarily removing the storage container 106 from the storage column 105. After removing the target storage container 106 from the storage column 105, the temporarily removed storage container 106 can be repositioned to the original storage column 105. However, the removed storage container 106 can alternatively be repositioned to other storage columns 105.

[0023] When storing the storage container 106 in a column 105, it is indicated that one of the container handling vehicles 201, 301, 401 picks up the storage container 106 from the pick-up port column 120 and transports the storage container to a position above the storage column 105 where the storage container will be stored. After removing all the storage containers 106 located at or above the target position within the stack 107, the container handling vehicles 201, 301, 401 position the storage container 106 at the desired position. The removed storage containers 106 can then be lowered back into the storage column 105 or repositioned to other storage columns 105.

[0024] To monitor and control an automated storage and retrieval system 1, such as monitoring and controlling the position of each storage container 106 within the framework structure 100, the contents of each storage container 106, and the movement of the container handling vehicles 201, 301, 401, such that a desired storage container 106 can be delivered to a desired location at a desired time point without the container handling vehicles 201, 301, 401 colliding with each other, the automated storage and retrieval system 1 includes a control system 500, which is typically computerized and typically includes a database for keeping track of the storage containers 106.

[0025] Figure 5 As shown in the prior art Figure 1 Schematic top view of the tracks of the automated storage and retrieval system 1. Figure 5 The track system 108, storage columns 105, port columns 119, 120, and a storage container 106 located in one of the plurality of storage columns 105 are shown. The port columns 119, 120 are part of the port area 510 of the access station, which, as explained above, is the location on the automated storage and retrieval system 1 where product items are removed from or positioned into the storage containers 106. The access station may be located at the bottom of the port columns 119, 120. The container handling vehicles 201, 301, 401 that deliver the storage container 106 to the port columns 119, 120 move towards the port columns such that the storage container 106 enters the port columns, and the storage container is delivered to the access station by lowering the storage container 106 through the port columns 119, 120.

[0026] The access station may also be located at the top of the port columns 119, 120. This may be the case when the access station is a robotic picking station (such as described in WO2016 / 198565A1). Here, the container handling vehicles 201, 301, 401 moving towards the port columns 119, 120 deliver the storage container 106 to the access station by lowering the storage container 106 through the port columns 119, 120 to a level immediately below the track system 108 (e.g., Z = 1) or by lowering the storage container 106 on the port columns 119, 120 above the track system 108 (i.e., Z = 0).

[0027] Also as Figure 5 shown, the port area 510 of the access station may include two buffer columns 519, 520 adjacent to the port columns 119, 120. The buffer columns 519, 520 are temporary locations where the container handling vehicles 201, 301, 401 hold the storage containers 106.

[0028] Buffer columns 519, 520 are used to schedule the container handling vehicles 201, 301, 401 to move towards the port columns 119, 120 early enough to meet the delivery time. To achieve maximum performance and throughput in the access station, the container handling vehicles 201, 301, 401 should reach the buffer columns 519, 520 before the previous container handling vehicle 201, 301, 401 finishes its work in the port columns 119, 120 of the access station. When the previous container handling vehicle 201, 301, 401 finishes its work in the port columns 119, 120 and moves away, the next container handling vehicle 201, 301, 401 that holds the storage container 106 in the buffer columns 519, 520 will be ready to move to the position of the previous container handling vehicle without unnecessary waiting. Allowing the container handling vehicles 201, 301, 401 to wait too long at the buffer columns 519, 520 may waste container handling vehicle resources. Therefore, the central control system 500 can determine whether to allocate the storage container 106 to the buffer columns 519, 520.

[0029] The storage container 106 should arrive at the port area 510 of the access station just in time. Waiting for the storage container 106 will reduce the performance of the access station (usually measured in storage containers per hour). When the position of the storage container 106 scheduled to be transported towards the port area 510 on the rail system 108 is too far from the port area 510, resulting in the storage container being unable to reach the port area 510 before the planned delivery, there will be a delay in the access station.

[0030] Since each buffer column 519, 520 replaces a storage column 105 of the automated storage and retrieval system 1, the number of buffer columns 519, 520 available for receiving storage containers at each access station is limited. The limited number of buffer columns 519, 520 restricts the number of storage containers 106 that can be scheduled / the number of storage containers that can move towards the port area 510 of the access station.

[0031] A system and method are needed to improve the performance of the access station. Summary of the Invention

[0032] The present invention is set forth and characterized in the independent claims, while the dependent claims describe other features of the present invention.

[0033] In one aspect, the present invention relates to a method for moving storage containers using one of a plurality of container handling vehicles on an orbital system, the orbital system being arranged to at least partially span the frame structure of an automated storage and retrieval system, the plurality of container handling vehicles being capable of operating on the orbital system to retrieve storage containers from storage rows arranged between upright members of the frame structure and to deliver storage containers to the storage rows, and to move storage containers to and from a port area of an access station, and wherein the following steps are performed by a central control system in communication with the access station and with a local controller in each of the plurality of container handling vehicles:

[0034] - Assigning a task to one of the plurality of container handling vehicles to retrieve a storage container from one of the storage rows and deliver the storage container to the port area;

[0035] - Instructing the container handling vehicle to retrieve a storage container from one of the storage rows;

[0036] - Determining a virtual buffer position on the orbital system between the storage row and the port area;

[0037] - Instructing the container handling vehicle to move the storage container towards the virtual buffer position on the orbital system;

[0038] - Repeatedly receiving data on the current position of the storage container on the orbital system and the current availability of the access station;

[0039] - When the current position of the storage container is different from the virtual buffer position and the column in the port area is available, instructing the container handling vehicle to move the storage container to the column in the port area; and

[0040] - Instructing the container handling vehicle to deliver the storage container into the column in the port area.

[0041] An advantage of the first aspect of the present invention is that it reduces the time for a storage container to wait at the access station for a long distance to reach the access station, thereby effectively improving the performance (storage containers per hour) of the access station. Another advantage of the first aspect of the present invention is that the virtual buffer position can reduce the number of buffer columns required. Reducing the number of buffer columns required between access stations allows the access stations to be positioned closer to each other.

[0042] In an embodiment of the first aspect, the step of determining a virtual buffer position on the orbital system includes: defining any storage row within a first predetermined radius of a column in the port area as the virtual buffer position.

[0043] In one embodiment of the first aspect, the step of determining a virtual buffer position on the rail system includes: selecting a storage column near the port area as the virtual buffer position, where the storage column is a storage column having a space for receiving storage containers.

[0044] In one embodiment of the first aspect, the step of determining a virtual buffer position on the rail system includes: selecting the storage column closest to the port area and having a space for receiving storage containers as the virtual buffer position.

[0045] In one embodiment of the first aspect, the method includes:

[0046] - When the current position of the storage container is at the virtual buffer position and the column in the port area is available, instructing the container handling vehicle to move to the column at the access station; and

[0047] - Instructing the container handling vehicle to deliver the storage container to the column at the access station.

[0048] In one embodiment of the first aspect, the method includes: when the current position of the storage container is at the virtual buffer position and the access station is unavailable, determining to instruct one of the plurality of container handling vehicles to deliver the storage container to the virtual buffer position.

[0049] In one embodiment of the first aspect, the method includes: when the current position of the storage container is at the virtual buffer position and the access station is unavailable, determining to instruct one of the plurality of container handling vehicles to deliver the storage container to a virtual buffer position different from the virtual buffer position.

[0050] In one embodiment of the first aspect, the method includes: when the deadline for delivering the storage container to the virtual buffer position exceeds the deadline threshold, and when the deadline for delivering the storage container to the column in the port area exceeds the deadline threshold, determining to instruct one of the plurality of container handling vehicles to deliver the storage container to the virtual buffer position.

[0051] In one embodiment of the first aspect, the method includes: when the idle time of the access station exceeds the idle threshold, determining to instruct one of the plurality of container handling vehicles to deliver the storage container to the virtual buffer position.

[0052] In a second aspect, the present invention relates to an automated storage and retrieval system, the automated storage and retrieval system comprising:

[0053] - A frame structure including upright members arranged to at least partially span the frame structure;

[0054] - Storage columns arranged in rows between the upright members of the frame structure;

[0055] - An access station, including a port area;

[0056] - A plurality of container handling vehicles, operable to retrieve storage containers from a storage row and deliver the storage containers to the storage row, and to move the storage containers to and from the port area of the access station, each container handling vehicle of the plurality of container handling vehicles including a local controller;

[0057] - A central control system, operable to communicate with the access station and with the local controller in each of the plurality of container handling vehicles, the central control system being adapted to:

[0058] - Assign a task to one of the plurality of container handling vehicles to retrieve a storage container from one of the storage rows and deliver the storage container to the port area;

[0059] - Instruct the container handling vehicle to retrieve a storage container from one of the storage rows;

[0060] - Determine a virtual buffer position on the track system between the storage row and the port area;

[0061] - Instruct the container handling vehicle to move the storage container towards the virtual buffer position;

[0062] - Repeatedly receive data on the current position of the storage container on the track system and the current availability of the access station;

[0063] - When the current position of the storage container is different from the virtual buffer position and a column in the port area is available, instruct the container handling vehicle to move the storage container to the column in the port area; and

[0064] - Instruct the container handling vehicle to deliver the storage container into the column in the port area.

[0065] An advantage of the second aspect of the present invention is that it reduces the time for a storage container to wait at the access station for a long distance to reach the access station, thereby effectively improving the performance of the access station (storage containers per hour). Another advantage of the first aspect of the present invention is that the virtual buffer position can reduce the number of buffer columns required. Reducing the number of buffer columns required between access stations allows the access stations to be positioned closer to each other.

[0066] In one embodiment of the second aspect, the system is adapted to determine a virtual buffer position on the track system by the following steps: Define any storage row within a first predetermined radius of one of the columns in the port area as the virtual buffer position.

[0067] In one embodiment of the second aspect, the system is adapted to determine a virtual buffer position on the track system by the following steps: select a storage column near the port area as the virtual buffer position, where the storage column is a storage column having a space for receiving a storage container.

[0068] In one embodiment of the second aspect, the system is adapted to determine a virtual buffer position on the track system by the following steps: select the storage column closest to the port area and having a space for receiving a storage container as the virtual buffer position.

[0069] In one embodiment of the second aspect, the system is adapted to:

[0070] - If the current position of the storage container is at the virtual buffer position and the column in the port area is available, instruct the container handling vehicle to move to the column at the access station; and

[0071] - Instruct the container handling vehicle to deliver the storage container to the column at the access station.

[0072] In one embodiment of the second aspect, the system is adapted to: when the current position of the storage container is at the virtual buffer position and the access station is unavailable, determine to instruct the container handling vehicle to deliver the storage container to the virtual buffer position.

[0073] In one embodiment of the second aspect, the system is adapted to: when the current position of the storage container is at the virtual buffer position and the access station is unavailable, determine to instruct the container handling vehicle to deliver the storage container to a virtual buffer position different from the virtual buffer position.

[0074] In one embodiment of the second aspect, the system is adapted to: when the deadline for delivering the storage container to the column in the port area exceeds the deadline threshold, instruct the container handling vehicle to deliver the storage container to the virtual buffer position.

[0075] In one embodiment of the second aspect, the system is adapted to: when the idle time of the access station exceeds the idle threshold, instruct the container handling vehicle to deliver the storage container to the buffer position.

[0076] In a third aspect, the present invention relates to a computer program product for a central control system of the second aspect of the present invention, wherein the computer program product includes instructions that, when executed on the control system, implement the method of the first aspect of the present invention.

[0077] The third aspect of the present invention has the same advantages as the first aspect and the second aspect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] The following attached drawings are provided to facilitate the understanding of the present invention. The drawings illustrate embodiments of the present invention, which will now be described only by way of example. In the drawings:

[0079] Figure 1 is a perspective view of the framework structure of an automatic storage and retrieval system of the prior art.

[0080] Figure 2 is a perspective view of a container handling vehicle of the prior art, which has an internally arranged cavity for carrying storage containers therein.

[0081] Figure 3 is a perspective view of a container handling vehicle of the prior art, which has a cantilever for carrying a storage container therebelow.

[0082] Figure 4 is a perspective view of a container handling vehicle of the prior art as viewed from below, which has an internally arranged cavity for carrying storage containers therein.

[0083] Figure 5 is a schematic diagram of an automatic storage and retrieval system of the prior art.

[0084] Figure 6 is a schematic diagram of an embodiment of the present invention.

[0085] Figure 7 is a schematic diagram of an embodiment of the present invention.

[0086] Figure 8 is a flowchart of a method according to an embodiment of the present invention. Detailed Embodiments

[0087] Hereinafter, embodiments of the present invention will be discussed in more detail with reference to the drawings. However, it should be understood that the drawings are not intended to limit the present invention to the subject matter depicted therein.

[0088] The framework structure 100 of the automatic storage and retrieval system 1 can be constructed in a manner similar to the framework structure 100 of the prior art described above in connection with Figures 1 to 5 That is, the framework structure 100 includes a plurality of upright members 102 and includes a first upper track system 108 extending in the X direction and the Y direction.

[0089] The framework structure 100 further includes a storage compartment, which takes the form of storage columns 105 provided between the members 102, wherein the storage containers 106 can be stacked into stacks 107 within the storage columns 105.

[0090] The framework structure 100 can be of any size. Specifically, it should be understood that the framework structure can be larger thanFigure 1 The frame structure disclosed therein is much wider and / or much longer and / or much deeper. For example, the frame structure 100 can have a horizontal extent of more than 700×700 columns and a storage depth of more than twelve containers.

[0091] Reference will now be made to Figures 6 to 8 One embodiment of an automated storage and retrieval system according to the present invention will be discussed in more detail.

[0092] Figure 6 and Figure 7 FIG. is a schematic view of an orbital system 108 that is arranged to extend at least partially across the frame structure of the automated storage and retrieval system, on which a plurality of container handling vehicles can run to retrieve storage containers 106 from storage columns 105 arranged in rows between the upright members (and optionally horizontal members) of the frame structure and to deliver the storage containers to the storage columns, and to move the storage containers 106 to and from the port area 510 of the access station. The port area 510 is represented by two port columns 119, 120 and two buffer columns 519, 520 adjacent to the port columns 119, 120.

[0093] The number of port columns 119, 120 in the port area 510 can vary based on the type of access station. One type of access station has one port column 119, 120 that is used for both retrieving and delivering storage containers. Another type of access station has a plurality of port columns 119, 120, where some of these port columns 119, 120 are arranged to retrieve storage containers 106 and other port columns 119, 120 are arranged to deliver storage containers 106. Other types of access stations can have fewer or more port columns 119, 120, where some or all of the port columns 119, 120 can be used for both retrieving and delivering storage containers 106.

[0094] The optional buffer columns 519, 520 adjacent to the port columns 119, 120 allow the container handling vehicles 106 to be ready to move into the port columns 119, 120 immediately after the previous container handling vehicle has moved away from the port columns 119, 120. Each access station has a limited number of buffer columns 519, 520, typically one or two buffer columns 519, 520 corresponding to each port column 119, 120. The buffer columns 519, 520 can have space for receiving the container handling vehicles 106.

[0095] To monitor and control an automated storage and retrieval system 1, for example, to monitor and control the position of each storage container 106 within the frame structure 100, the contents of each storage container 106, and the movement of the container handling vehicles 201, 301, 401 such that a desired storage container 106 can be delivered to a desired location at a desired time point without the container handling vehicles 201, 301, 401 colliding with each other, the automated storage and retrieval system 1 includes a central control system 500, which includes a database for tracking the storage containers 106. The central control system 500 also communicates with the access station and receives information about the status of the port columns 119, 120 and the buffer columns 519, 520 adjacent to the port columns 119, 120 from the access station. For example, when a storage container 106 is ready to return to the storage column 105, the status may include information about whether there is a storage container 106 in the columns 119, 120, 519, 520 of the access station, etc. The central control system 500 executes at any time a plan of which storage containers 106 should be moved to the access station, determines when a storage container 106 must be picked up by the container handling vehicles 201, 301, 401 so that the storage container 106 arrives at the access station in time, and calculates the route for the storage container 106 to travel in the columns 119, 120, 519, 520 towards the port area 510 of the access station. The central control system performs all these tasks for multiple container handling vehicles 201, 301, 401 simultaneously and repeats the calculation frequently as needed.

[0096] In the prior art, as described in reference Figure 5 when there is no valid target location (i.e., the available port columns 119, 120, or the available buffer columns 519, 520 when the delivery is within a predetermined time and the port columns are occupied), the central control system 500 does not move the storage container 106 towards the port area 510 of the access station. When the central control system 500 arranges for the storage container 106 on the container handling vehicles 201, 301, 401 to go to the port area 510, the central control system checks whether the storage container 106 is too far from the port area 510 to arrive on time. Then, the central control system 500 will instruct the container handling vehicles 201, 301, 401 to deliver the storage container 106 to a storage column 105 closer to the port area 510. The goal is to move the farther storage containers 106 and place them in advance at a location closer to the port area 510. Then, the container handling vehicles 201, 301, 401 will be assigned another task, and the storage container 106 currently located at a position closer to the port area 510 will be assigned to another container handling vehicle 201, 301, 401 to be moved to the port area 510 later.

[0097] In one embodiment of the present invention, the central control system 500 allows the storage container 106 to move towards the port area 510 when there are no available port columns or buffer columns 119, 120, 519, 520 in the port area 510, and allows the routing of the storage container 106 via temporary target positions or virtual buffer positions 610, 710 on the track system 108.

[0098] Figure 8 is an exemplary flowchart of a method 800 according to an embodiment of the present invention. The method 800 is performed by an automated storage and retrieval system 1 described with reference to the accompanying drawings, specifically, Figure 1 , Figure 6 and Figure 7 .

[0099] In a first step 801, the central control system 500 assigns a task to one of the plurality of container handling vehicles 201, 301, 401 to retrieve the storage container 106 from one of the storage columns 105 in the storage column and deliver the storage container 106 to the port area 510. The assignment can be performed as part of a routing optimization process involving a plurality of storage container handling vehicles 201, 301, 401 and a plurality of storage containers 106. The routing optimization process can use the A* algorithm.

[0100] In the next step 802, the central control system 500 instructs the storage container handling vehicles 201, 301, 401 to retrieve the storage container 106 from the storage column 105.

[0101] In the next step 803 (which can be combined with the routing optimization step of the first step 801), the central control system 500 determines virtual buffer positions 610, 710 on the track system 108 between the storage column 105 and the port area 510.

[0102] In one embodiment, as Figure 6 shown, the step of determining the virtual buffer position 610 on the track system includes: defining any storage column 105 within a first predetermined radius 530 of one of the columns 119, 120, 519, 520 in the port area 510 as the virtual buffer position 610. In this case, the routing optimization process will optimize the route for any storage column 105 within the first predetermined radius 530 of the columns 119, 120, 519, 520 as the target position.

[0103] In one embodiment, as Figure 7As shown, the steps for determining the virtual buffer positions on the rail system 108 include: selecting a storage column 105 near the port area 510 as the virtual buffer position 710, where the storage column 105 is a storage column having space for receiving storage containers 106. Being near the port area 510 can be evaluated based on a time criterion (e.g., "near in time") or a space criterion (e.g., "near in space"). In this case, the route arrangement optimization process optimizes the route for the virtual buffer position 710 as the target position.

[0104] In one embodiment, as also Figure 7 As shown, the steps for determining the virtual buffer positions on the rail system 108 include: selecting the storage column 105 closest to the port area 510 and having space for receiving storage containers 106 as the virtual buffer position 710. Being closest to the port area 510 can be evaluated based on a time criterion (e.g., "near in time") or a space criterion (e.g., "near in space"). In this case, the route arrangement optimization process optimizes the route for the virtual buffer position 710 as the target position.

[0105] In the next step 804, the central control system 500 instructs the container handling vehicles 201, 301, 401 to move the storage containers 106 towards the selected virtual buffer positions 610, 710.

[0106] In the subsequent steps 805 and 806, as the container handling vehicles 201, 301, 401 move the storage containers 106 towards the virtual buffer positions 610, 710, the central control system 500 repeatedly receives data on the current positions of the storage containers 106 and / or the container handling vehicles 201, 301, 401 on the rail system 108 and the current availability of the access stations. These steps can be combined with the route arrangement optimization step of the first step 801 and are executed as frequently as needed.

[0107] The database of the central control system 500 knows the positions of all the storage containers 106. The access station also notifies the central control system 500 when it is ready to retrieve a storage container 106 from the port columns 119, 120 of the port area 510 of the access station.

[0108] When the current position of the storage container 106 is different from the virtual buffer positions 610, 710 and the columns 119, 120, 519, 520 of the port area 510 are available, the central control system 500 instructs the container handling vehicles 201, 301, 401 carrying the storage container 106 to move the storage container 106 to the port columns 119, 120 or the buffer columns 519, 520. That is, when the port area 510 of the access station becomes available while the storage container 106 is moving towards the virtual buffer positions 610, 710, the route of the storage container 106 is rearranged and it no longer goes to the virtual buffer positions 610, 710. After the storage container 106 is in the port area 510 of the access station, the central control system 500 instructs the container handling vehicles 201, 301, 401 to deliver the storage container 106 to one of the columns 119, 120, 519, 520 of the port area 510 of the access station. Then, the container handling vehicles 201, 301, 401 deliver the storage container 106 to the columns 119, 120, 519, 520 and move away to be assigned other tasks.

[0109] In the case where the storage container 106 is located at the virtual buffer positions 610, 710 before the port area 510 is available, the next step 808 is to wait at the virtual buffer positions 610, 710 for the port area 510 to become available, that is, the following steps: when the current position of the storage container 106 is at the virtual buffer positions 610, 710 and the columns 119, 120, 519, 520 of the port area 510 are available, instruct the container handling vehicles 201, 301, 401 to move to the columns 119, 120, 519, 520 of the port area 510; and instruct the container handling vehicles 201, 301, 401 to deliver the storage container 106 to the columns 119, 120, 519, 520 of the port area 510. These steps can be combined with the route arrangement optimization steps of the first step 801 and are executed frequently as needed.

[0110] When the virtual buffer positions 610 are within the first predetermined radius 530 of columns 119, 120, 519, and 520 of the port area 510, there are multiple available virtual buffer positions 610. Due to the frequent execution of the route arrangement optimization step, the container handling vehicles 201, 301, 401 holding the storage containers 106 may move around. In one embodiment, it is allowed for the storage container 106 to move to a virtual buffer position 611 that is outside the first predetermined radius 530 of columns 119, 120, 519, and 520 of the port area 510 and within the second predetermined radius 540 of columns 119, 120, 519, and 520 of the port area 510. After the storage container 106 is at a position 612 outside the second predetermined radius 540, the container handling vehicles 201, 301, 401 are instructed to move the storage container to a virtual buffer position within the first predetermined radius 530.

[0111] If the storage container 106 in the container handling vehicles 201, 301, 401 waits too long at the virtual buffer positions 610, 710, it will waste the resources of the container handling vehicles, and unnecessary waiting should be avoided.

[0112] In step 809, when the current position of the storage container 106 is at the virtual buffer positions 610, 710 and the access station is unavailable, the central control system 500 instructs the container handling vehicles 201, 301, 401 to deliver the storage container 106 to the virtual buffer positions 610, 710. Then, the storage container 106 is stored in the storage row 105 below the designated virtual buffer positions 610, 710 on the rail system, or when the container handling vehicle places the storage container 106 at the horizontal height (z = 0) of the rail system, the storage container is stored on the virtual buffer positions 610, 710.

[0113] When the virtual buffer positions 610 are within the first predetermined radius 530 of columns 119, 120, 519, and 520 of the port area 510, there are multiple available virtual buffer positions 610. Due to the frequent execution of the route arrangement optimization step, the container handling vehicles 201, 301, 401 holding the storage containers 106 are likely to move around. In step 809, when the current position of the storage container 106 is at the virtual buffer position 610 and the access station is unavailable, the control system 500 instructs the container handling vehicles 201, 301, 401 to deliver the storage container 106 to the virtual buffer positions 610’, 611, 612.

[0114] In one embodiment, step 809 is as follows: when the deadline for delivering the storage container 106 to columns 119, 120, 519, 520 in the port area 510 exceeds the deadline threshold, instruct the container handling vehicles 201, 301, 401 to deliver the storage container 106 to the virtual buffer locations 610, 610', 611, 612, 710.

[0115] In one embodiment, step 809 is as follows: when the idle time of the access station exceeds the idle threshold, determine to instruct the container handling vehicles 201, 301, 401 to deliver the storage container 106 to the virtual buffer locations 610, 610', 611, 612, 710. The central control system 500 can automatically determine the idle threshold based on the statistical analysis of the automated storage and retrieval system 1.

[0116] In one embodiment, the present invention can be provided in the form of a computer program product for the central control system 500. The computer program product includes instructions that implement the steps of method 800 when executed on the central control system.

[0117] In the foregoing description, various aspects of the delivery vehicle and the automated storage and retrieval system according to the present invention have been described with reference to illustrative embodiments. For illustrative purposes, specific numbers, systems, and configurations have been set forth to provide a thorough understanding of the system and how it operates. However, the description is not intended to be construed in a limiting sense. Various modifications and variations of the illustrative embodiments and other embodiments of the system that are obvious to those skilled in the art to which the disclosed subject matter pertains are considered to fall within the scope of the present invention.

[0118] List of reference numerals

[0119]

Claims

1. A method for moving a storage container (106) using one of a plurality of container handling vehicles (201, 301, 401) on an orbital system (108), the orbital system being arranged to at least partially span a frame structure (100) of an automated storage and retrieval system (1), the plurality of container handling vehicles (201, 301, 401) being operable on the orbital system (108) to retrieve the storage container (106) from storage rows (105) arranged in rows between upright members (102) of the frame structure (100) and to dispense the storage container (106) into the storage rows, and to move the storage container (106) to and from a port area (510) of an access station, and wherein, The following steps are performed by a central control system (500) that communicates with the access station (510) and with the local controller in each of the plurality of container handling vehicles (201, 301, 401): - Assign a task to one of the plurality of container handling vehicles (201, 301, 401) to retrieve a storage container (106) from one of the storage columns (105) and deliver the storage container (106) to the port area (510); - Instruct the container handling vehicle (201, 301, 401) to retrieve the storage container from one of the storage columns (105); - Determine a virtual buffer location (610, 710) between the storage column (105) and the port area (510) on the track system (108); - Instruct the container handling vehicle (201, 301, 401) to move the storage container (106) towards the virtual buffer location (610, 710) on the track system (108); - Repeatedly receive data on the current position of the storage container (106) on the track system (108) and the current availability of the access station (510); - When the current position of the storage container (106) is different from the virtual buffer location (610, 710) and the columns (119, 120, 519, 520) of the port area (510) are available, instruct the container handling vehicle (201, 301, 401) to move the storage container to the columns (119, 120, 519, 520) of the port area (510); and - Instruct the container handling vehicle (201, 301, 401) to deliver the storage container (106) into the columns (119, 120, 519, 520) of the port area (510).

2. The method according to claim 1, wherein The step of determining the virtual buffer location on the track system includes defining any storage column (105) within a first predetermined radius (530) of one of the columns (119, 120, 519, 520) of the port area (510) as the virtual buffer location (610).

3. The method according to claim 1, wherein, The step of determining the virtual buffer location on the track system includes: selecting a storage column (105) close to the port area (510) as the virtual buffer location (710), wherein the storage column (105) is a storage column having space to receive the storage container (106).

4. The method according to claim 1, wherein The step of determining the virtual buffer location on the track system includes: selecting the storage column (105) closest to the port area (510) and having space to receive the storage container (106) as the virtual buffer location (710).

5. The method according to any one of the preceding claims, comprising: - When the current position of the storage container (106) is at the virtual buffer position (610, 710) and the columns (119, 120, 519, 520) of the port area (510) are available, instruct the container handling vehicle (201, 301, 401) to move to the columns (119, 120, 519, 520) of the access station (510); and - Instruct the container handling vehicle (201, 301, 401) to deliver the storage container (106) into the columns (119, 120, 519, 520) of the port area (510).

6. The method according to any one of the preceding claims, comprising: When the current position of the storage container (106) is at the virtual buffer position (610, 710) and the access station is unavailable, determine to instruct the container handling vehicle (201, 301, 401) to deliver the storage container into the virtual buffer position (610, 710).

7. The method according to claim 2, or the method according to any one of claims 5 and 6 which are dependent on claim 2, comprises: When the current position of the storage container (106) is at the virtual buffer position and the access station is unavailable, determine to instruct the container handling vehicle (201, 301, 401) to deliver the storage container into a virtual buffer position (610’, 611, 612) different from the virtual buffer position (610).

8. The method according to claim 6 or 7, comprising: When the deadline for delivering the storage container (106) into the columns (119, 120, 519, 520) of the port area (510) exceeds the deadline threshold, instruct the container handling vehicle (201, 301, 401) to deliver the storage container (106) into the virtual buffer position (610, 610’, 611, 612, 710).

9. The method according to any one of claims 6 to 8, comprising: When the idle time of the access station (510) exceeds the idle threshold, instruct the container handling vehicle (201, 301, 401) to deliver the storage container (106) into the virtual buffer position (610, 610’, 611, 612, 710).

10. An automatic storage and retrieval system (1), comprising: - A frame structure (100), including upright members (102); - A rail system (108), arranged to at least partially span the frame structure (100); - Storage columns (105), arranged in rows between the upright members (102) of the frame structure (100); - An access station, including a port area (510); - A plurality of container handling vehicles (201, 301, 401), operable to retrieve storage containers (106) from the storage columns (105) and deliver the storage containers (106) into the storage columns, and move the storage containers (106) to and from the port area (510) of the access station, each container handling vehicle of the plurality of container handling vehicles (201, 301, 401) including a local controller; - A central control system (500) operable to communicate with the access station (510) and with a local controller in each of the plurality of container handling vehicles (201, 301, 401), the central control system (500) being adapted to: - Assign a task to one of the plurality of container handling vehicles (201, 301, 401) to retrieve a storage container (106) from one of the storage rows (105) and deliver the storage container (106) to the port area (510); - Instruct the container handling vehicle (201, 301, 401) to retrieve the storage container from one of the storage rows (105); - Determine a virtual buffer position (610, 710) between the storage row (105) and the port area (510) on the track system (108); - Instruct the container handling vehicle (201, 301, 401) to move the storage container (106) towards the virtual buffer position (610, 710); - Repeatedly receive data on the current position of the storage container (106) on the track system (108) and the current availability of the access station (510); - When the current position of the storage container (106) is different from the virtual buffer position (610, 710) and the columns (119, 120, 519, 520) of the port area (510) are available, instruct the container handling vehicle (201, 301, 401) to move the storage container to the columns (119, 120, 519, 520) of the port area (510); and - Instruct the container handling vehicle (201, 301, 401) to deliver the storage container (106) into the columns (119, 120, 519, 520) of the port area (510).

11. The system according to claim 10, wherein, The step of determining the virtual buffer position on the track system includes: defining any storage row (105) within a first predetermined radius (530) of one of the columns (119, 120, 519, 520) of the port area (510) as the virtual buffer position (610).

12. The system according to claim 10, wherein, The system is adapted to determine the virtual buffer position on the track system by the following steps: selecting a storage row (105) close to the port area (510) as the virtual buffer position (710), wherein the storage row (105) is a storage row having space to receive the storage container (106).

13. The system according to claim 10, wherein, The system is adapted to determine the virtual buffer position on the track system by the following steps: selecting the storage row (105) closest to the port area (510) and having space to receive the storage container (106) as the virtual buffer position (710).

14. The system according to any one of claims 10 to 13, wherein, The system is adapted to: - When the current position of the storage container (106) is at the virtual buffer position (610, 710) and the columns (119, 120, 519, 520) of the port area (510) are available, instruct the container handling vehicle (201, 301, 401) to move to the columns (119, 120, 519, 520) of the access station (510); and - Instruct the container handling vehicle (201, 301, 401) to deliver the storage container (106) into the columns (119, 120, 519, 520) of the port area (510).

15. The system according to any one of claims 10 to 14, wherein, The system is adapted to: when the current position of the storage container (106) is at the virtual buffer position (610, 710) and the access station is unavailable, determine to instruct the container handling vehicle (201, 301, 401) to deliver the storage container to the virtual buffer position (610, 710).

16. The system according to claim 11, or the system according to any one of claims 14 and 15 which are dependent on claim 11, wherein, The system is adapted to: when the current position of the storage container (106) is at the virtual buffer position and the access station is unavailable, determine to instruct the container handling vehicle (201, 301, 401) to deliver the storage container to a virtual buffer position (610’, 611, 612) different from the virtual buffer position (610).

17. The system according to claim 16 or 17, wherein, The system is adapted to: when the deadline for delivering the storage container (106) into the columns (119, 120, 519, 520) of the port area (510) exceeds the deadline threshold, instruct the container handling vehicle (201, 301, 401) to deliver the storage container (106) to the virtual buffer position (610, 610’, 611, 612, 710).

18. The system according to any one of claims 16 to 18, wherein, The system is adapted to: when the idle time of the access station (510) exceeds the idle threshold, instruct the container handling vehicle (201, 301, 401) to deliver the storage container (106) to the buffer position (610, 610’, 611, 612, 710).

19. A computer program product for a central control system (500) in a system according to any one of claims 10 to 18, wherein, The computer program product includes instructions that, when executed on the control system, implement the method according to claims 1 to 9.

Images