Method for operating automated storage / retrieval system

Abstract

To provide a method for operating an automated storage / retrieval system, and to provide an automated storage / retrieval system.SOLUTION: There is provided a method for operating an automated storage / retrieval system, in which the method comprises, when it is detected by a central control unit 15 that the access of a first container-handling vehicle 2 to a target cell 12 which is one of a plurality of grid cells is blocked by a second container-handling vehicle 3, transmitting a data signal, which instructs the first container-handling vehicle 2 to move into the target cell 12 if the second container handling vehicle 3 is beyond a predetermined distance D, from the central control unit 15 to the vehicle control unit of the first container handling vehicle 2.SELECTED DRAWING: Figure 15

Description

[Technical field]

[0001] The present invention relates to a method of operating an automated storage and retrieval system, and to an automated storage and retrieval system. [Background technology]

[0002] FIG. 1 discloses a typical prior art automated storage and retrieval system 1 comprising a framework structure 100, and FIGS. 2a and 2b disclose prior art container handling vehicles 101, 201 of such a system 1.

[0003] The frame structure 100 comprises a number of upright members 102 and a number of horizontal members 103 supported by the upright members 102. The members 102, 103 may typically be made of metal, for example extruded aluminium profiles.

[0004] The framework structure 100 defines a storage grid 104 with storage columns 105 arranged in rows in which storage containers 106, also known as bins, are stacked, one on top of another, to form a stack 107. Each storage container 106 can typically hold multiple product items (not shown), which may be equal or different types of products, depending on the application. The storage grid 104 prevents the containers in the stack 107 from moving horizontally and guides the storage containers 106 from moving vertically, but typically does not otherwise support the storage containers 106 when stacked.

[0005] A portion of the horizontal member 103 comprises a rail system 108 arranged in a grid pattern across the tops of the storage columns 105, on which a plurality of container handling vehicles 101 are operated to raise and lower storage containers 106 from and into the storage columns 105, as well as to transport the storage containers 106 above the storage columns 105. The rail system 108 comprises a first set of parallel rails 110 arranged across the top of the frame structure 100 to guide movement of the container handling vehicles 101 in a first direction X, and a second set of parallel rails 111 arranged perpendicular to the first set of rails 110 to guide movement of the container handling vehicles 101 in a second direction Y that is perpendicular to the first direction X. In this manner, the rail system 108 defines grid columns 112 above which the container handling vehicles 101 can move laterally above the storage columns 105, i.e. in a plane parallel to the horizontal XY plane.

[0006] Each container handling vehicle 101 comprises a vehicle body 101a and a first set of wheels 101b and a second set of wheels 101c that allow the container handling vehicle 101 to move laterally in the X and Y directions, respectively. In Fig. 2a two wheels can be seen in each set. The first set of wheels 101b are configured to engage two adjacent rails of the first set of rails 110 and the second set of wheels 101c are configured to engage two adjacent rails of the second set of rails 111. The wheels 101b, 101c of each set are configured to engage two adjacent rails of the second set of rails 111. c can be raised or lowered so that the first set of wheels 101b and / or the second set of wheels 101c are rotated at any simultaneous instant. The wheels 110, 111 of each set can be engaged.

[0007] Each container handling vehicle 101 further comprises a lifting device (not shown in FIG. 2a) for transporting a storage container 106 vertically, e.g. to raise the storage container 106 out of the storage column 105 or to lower the storage container 106 into the storage column 105. The lifting device comprises a gripping device (not shown) adapted to be engaged with the storage container 106, which gripping device can be lowered from the vehicle body 101a such that the position of the gripping device relative to the vehicle body 101a can be adjusted in a third direction Z orthogonal to the first direction X and the second direction Y.

[0008] Conventionally, and in this application, Z=1 identifies the topmost layer of the grid 104, i.e., the layer immediately below the rail system 108, Z=2 identifies the second layer below the rail system 108, Z=3 identifies the third layer, and so on. In the exemplary prior art storage grid disclosed in FIG. 1, Z=8 identifies the bottommost layer of the grid 104. Similarly, X=1 identifies the first row column in the X direction from the corner selected as the origin, and Y=1 identifies the first row column in the Y direction from the corner selected as the origin. As a result, using the Cartesian coordinate system X, Y, Z shown in FIG. 1 as an example, a storage container identified as 106' in FIG. 1 can be said to occupy a grid location or grid cell X=10, Y=2, Z=3. A container handling vehicle 101 can be said to move in layer Z=0, and each grid column 112 can be identified by its X and Y coordinates.

[0009] Each container handling vehicle 101 comprises a storage compartment or space for receiving and accommodating the storage containers 106 as they are transported across the rail system 108. The storage space may comprise a centrally located cavity within the vehicle body 101a, as described, for example, in WO2014 / 090684A1, the contents of which are incorporated herein by reference.

[0010] Alternatively, the container handling vehicle 201 may have a cantilevered structure as shown in FIG. 2b, as described in NO317366, the contents of which are also incorporated herein by reference.

[0011] The container handling vehicle 101 may have a footprint generally equal to an area defined by the lateral extent in the X and Y directions of the grid columns 112 (i.e., a footprint covering an area having dimensions in the X and Y directions), as described, for example, in WO 2015 / 193278 A1, the contents of which are incorporated herein by reference. As used herein, the term "lateral" may mean "horizontal".

[0012] Alternatively, the container handling vehicle 101 may have a footprint larger than the horizontal area defined by the grid columns 112, for example as disclosed in WO2014 / 090684A1.

[0013] The rail system 108 may be a single-run system as shown in Figure 3. Alternatively, the rail system 108 may be a double-run system as shown in Figure 4, which allows a container handling vehicle 101 having a footprint generally matching the lateral area defined by a grid column 112 to travel along a row of grid columns, even when another container handling vehicle 101 is positioned adjacent to and above the row of grid columns. Both single-run and double-run systems, or a combination of single and double runways, may be used. The system used forms a grid pattern in a horizontal plane P comprising a plurality of rectangular uniform grid locations or grid cells 122, where each grid cell 122 comprises a grid opening 115 bounded by a pair of rails 110a, 110b of a first set of rails 110 and a pair of rails 111a, 111b of a second set of rails 111. In Figure 4, the grid cells 122 are indicated by dashed boxes.

[0014] Each grid cell 122 has a width that is typically within the range of 30 cm to 150 cm intervals, and a length that is typically within the range of 50 cm to 200 cm intervals. Each grid opening 115 has a width and length that are smaller than the width and length of the grid cell 122, typically 2 cm to 10 cm.

[0015] Within the storage grid 104, the majority of the grid columns 112 are storage columns 105, i.e., grid columns 105 where storage containers 106 are stored in stacks 107. However, typically, the grid 104 has at least one grid column 112 that is not used to store storage containers 106 but that has a location where the storage containers 106 can be dropped off and / or picked up by the container handling vehicle 101 so that the storage containers 106 can be transported to an access station (not shown here) where the storage containers 106 can be accessed from outside the grid 104 or transferred out of or into the grid 104. In the art, such locations are typically referred to as "ports" and the grid columns 112 where the ports are located can be referred to as "port columns" 19, 20.

[0016] 1 comprises two port columns 19 and 20. The first port column 19 may, for example, be a dedicated unloading port column where a container handling vehicle 101 may unload a storage container to be transported to an access or transfer station, and the second port column 20 may be a dedicated loading port column where a container handling vehicle 101 may load a storage container 106 that has been transported from an access or transfer station to the grid 104.

[0017] An access station may typically be a picking or stocking station where product items are removed from or placed into a storage container 106. In a picking or stocking station, the storage container 106 is typically never removed from the automated storage and retrieval system 1, but is placed back into the grid 104 when accessed. Ports may also be used to transfer storage containers out of or into the grid 104, such as to transfer the storage container 106 to another storage facility (e.g., another grid, or another automated storage and retrieval system), to a delivery vehicle (e.g., a train or lorry), or to a production facility.

[0018] A conveyor system comprising a conveyor belt is typically employed to transport the storage containers between the ports 19, 20 and the access stations. If the ports and the access stations are located at different levels, the conveyor system may be equipped with lifting devices for vertically transporting the storage containers 106 between the ports 19, 20 and the access stations.

[0019] A conveyor system may be configured to transport the storage containers 106 between the different grids, for example as described in WO2014 / 075937A1, the contents of which are incorporated herein by reference.

[0020] WO2016 / 198467A1, the contents of which are incorporated herein by reference, discloses an example of a prior art access system having a conveyor belt (Figures 5a and 5b herein) and a frame installation runway (Figures 6a and 6b herein) for transporting storage containers between a port and a work station where the storage containers can be accessed by an operator.

[0021] When a storage container 106 stored in the grid 104 disclosed in FIG. 1 is to be accessed, one of the container handling vehicles 101 is instructed to retrieve the target storage container 106 from its position in the grid 104 and transport the target storage container 106 to the drop-off port 19. This operation involves moving the container handling vehicle 101 to a grid location above the storage column 105 where the target storage container 106 is located, retrieving the storage container 106 from the storage column 105 using a lifting device (not shown) of the container handling vehicle 101, and transporting the storage container 106 to the drop-off port 19. When the target storage container 106 is located deep within the stack 107, i.e., when one or more of the other storage containers are located above the target storage container 106, this operation further involves temporarily moving the storage container located above before lifting the target storage container 106 from the storage column 105. This step, sometimes referred to in the art as "digging", may be performed using the same container handling vehicle that is later used to transport the target storage container to the unloading port 19, or using one or more other cooperating container handling vehicles. Alternatively or additionally, the automated storage and retrieval system 1 may have a container handling vehicle dedicated to the task of temporarily removing the storage container from the storage column 105. Once the target storage container 106 has been removed from the storage column 105, the temporarily removed storage container may be relocated back into the original storage column 105. However, alternatively, the removed storage container may be repositioned to another storage column.

[0022] If a storage container 106 is to be stored in grid 104, one of the container handling vehicles 101 is directed to load the storage container 106 from the loading port 20 and transport the container 106 to a grid location above the storage column 105 where the storage container 106 is to be stored. After any storage containers located at or above the target location in the storage column stack 107 are retrieved, the container handling vehicle 101 places the storage container 106 in the desired location. The retrieved storage container can then be lowered back into storage column 105 or repositioned to another storage column.

[0023] The automated storage and retrieval system 1 includes a central control system, typically computerized, that monitors and controls the location of each storage container 106 within the grid 104; the contents of each storage container 106; and the movement and traffic flow of the container handling vehicles 101, for example, to enable the container handling vehicles 101 to deliver the desired storage containers 106 to the desired locations at the desired times without causing the container handling vehicles 101 to collide with each other.

[0024] The container handling vehicle includes a vehicle control unit communicably connected to a central control system for transmitting and receiving data signals. The vehicle control unit is connected to the drive means, lifting means, and any sensors on the vehicle and can relay and / or process data signals between the vehicle components and the central control system. As is known from prior art document WO2018082972, sensors on the container handling vehicle, and thus the vehicle control unit, which are positioned near the track means whenever it passes a track intersection, can track its position on the grid, which can then be relayed to a central control system.

[0025] A problem with known traffic flow management is that an area surrounding a particular cell, such as a port 19, 20 or other column that is frequently accessed by container handling vehicles, may become congested with container handling vehicles 101 that are directed to drop off or pick up storage containers 106. When one container handling vehicle 101 blocks access to a target cell 12, which may be, for example, one of the grid cells 122, or to one of the ports 19, 20, another container handling vehicle 101 may start queuing on an adjacent cell to wait for access to the target cell 12. It is desired that the container handling vehicle 101 blocking access to the target cell 12 be moved away from its blocking position and then the queuing container handling vehicle be moved into the target cell 12 as quickly as possible.

[0026] One problem with the prior art is that the location of a container handling vehicle is not known with certainty until it has passed a track intersection. Here, the location of the container handling vehicle may be transmitted to a central control system which processes this information to ascertain whether the queuing container handling vehicle can move into the target cell 12. This creates delays due to commands being relayed through and processed within the central control system. Additionally, delays are also created in situations where access to the target cell 12 is free but the previously blocking container handling vehicle has not been identified and has not transmitted its new location. Also, relaying this information can only utilize limited capacity on the communication bandwidth between the container handling vehicle 101 and the control system.

[0027] In view of the above, it is desirable to provide an automated storage and retrieval system, and a method for operating such a system, that overcomes or at least mitigates one or more of the above-referenced problems associated with the use of prior art storage and retrieval systems. Summary of the Invention [Means for solving the problem]

[0028] The invention is set forth and characterized in the main claims, whereas the dependent claims describe optional features of the invention. Thus, in one aspect, the present invention relates to a method of operating an automated storage and retrieval system, the method comprising: - a rail system comprising a first set of parallel rails arranged in a horizontal plane and extending in a first direction and a second set of parallel rails arranged in the horizontal plane and extending in a second direction perpendicular to the first direction, the first and second sets of rails forming a grid pattern in the horizontal plane comprising a plurality of adjacent grid cells; - a central control unit configured to receive, transmit, and process data signals of a plurality of container handling vehicles for handling storage containers of the automated storage and retrieval system, Each container handling vehicle, Vehicle body, a wheel assembly disposed within a vehicle body, the wheel assembly being configured to move the vehicle along the rail system in both a first direction and a second direction; a vehicle control unit configured to receive a data signal from the central control unit, to transmit a data signal to the central control unit, and to process the data signal of the central control unit; a proximity sensor system configured to detect another container handling vehicle of the plurality of container handling vehicles and determine whether the other container handling vehicle is within a predetermined distance; Equipped with Central control unit and Equipped with The method: - detecting, with the central control unit, that access of a first container handling vehicle to a target cell, the target cell being one of the plurality of grid cells, is being blocked by a second container handling vehicle; - transmitting a data signal from the central control unit to a vehicle control unit of the first container handling vehicle instructing the first container handling vehicle to move into the target cell if the second container handling vehicle is outside the predetermined distance; Includes.

[0029] The present invention therefore allows container handling vehicles accessing a target cell to queue more efficiently and quickly, since the first container handling vehicle does not have to wait for the second handling vehicle to send its new cell location to the central control unit and / or for the central control unit to process this information and command the first container handling vehicle to move into the target cell. The present invention may be particularly advantageous when container handling vehicles operate on a rail system in the vicinity of a port column and when a container handling vehicle with a container delivery vehicle operates on a rail system to deliver storage containers to be picked at an access point. The present invention may be particularly advantageous when the target cell is empty or when it is deemed acceptable for the first container handling vehicle to start moving into the target cell, which is not done in the prior art because it requires a command from the central control unit to move. The present invention may therefore allow the first container handling vehicle to start moving towards the target cell while the second container handling vehicle is still partially inside the target cell. The present invention also allows for more efficient bandwidth usage within the automated storage system because unnecessary signaling back and forth between the central control unit and the container handling vehicles is reduced, and the processing power of the central control unit may be used more efficiently because the first container handling vehicle does not require a separate command to move into the target cell if the control unit calculates that the target cell is empty, as is required in the prior art.

[0030] Transmitting a data signal from the central control unit to the vehicle control unit of the first container handling vehicle may include instructing the first container handling vehicle not to move into the target cell if the second container handling vehicle is within the predetermined distance, such that the first container handling vehicle may move if and only if the second container handling vehicle is a sufficient distance away.

[0031] The proximity sensor system may be configured to detect when another container handling vehicle is within a predetermined distance, i.e., configured by a Boolean variable, where the first container handling vehicle moves if the distance of the other container handling vehicle is greater than a given value for the predetermined distance. The proximity sensor system may be further configured to detect when another container handling vehicle is within a predetermined distance, i.e., configured by a Boolean variable, where the first container handling vehicle moves if the distance of the other container handling vehicle is greater than a given value for the predetermined distance. The proximity sensor system detects any container handling vehicle outside said distance range. Thus, the first container handling vehicle will only move if the proximity sensor system detects that the second vehicle is outside the predetermined distance range. To achieve redundancy in case of failure to detect that there is another container handling vehicle within the predetermined distance range, the second container handling vehicle may have a redundancy measure, as known in the art, such as sending a signal to the central control unit that the second container handling vehicle has moved and is not obstructing the target cell. Also, the first container handling vehicle may send a signal to the central control unit that it has arrived at the target cell, as known in the art.

[0032] A proximity sensor system can usually measure a target value up to a given distance, for example 2 meters, because this may be the length of a grid cell. However, the predetermined distance may be calculated and set by the central control unit depending on the requirements and specifications of the automated storage system, such as the size and moving speed of the container handling vehicle, and the size of the grid cell, which may be determined by the direction of movement of the container handling vehicle. Also, each vehicle control unit may calculate the predetermined distance based on parameters such as the size and moving speed of the container handling vehicle and based on which direction the container handling vehicle is moving. The predetermined distance may be provided in a data signal sent from the central control system, so that the distance can change to an appropriate distance depending on what the central control system calculates. For example, the predetermined distance may be reduced during a congestion period. The predetermined distance may be smaller than the size of a grid cell in either of two perpendicular directions. The target cell may be a cell that is frequently accessed by container handling vehicles and therefore receives a significant amount of traffic, such as a grid cell located above a port column. However, the invention is not limited to port cells only, but can be realized to improve traffic handling in all types of cells, such as cells located above storage columns. The container handling vehicles can comprise container delivery vehicles, and thus the target cell may be located below a port column of the grid or at an access point, typically at the edge of a rail system, where the container delivery vehicle is for delivering the storage container to be picked.

[0033] Typically, a second handling vehicle may obstruct access to a target cell if it at least partially covers said target cell. However, the second handling vehicle may also obstruct access to a target cell if, for example, it occupies a cell adjacent to the target cell and the first handling vehicle has an extension greater than the lateral area defined by the grid column. Thus, the term moving away does not necessarily imply that the second container handling vehicle is above or covering the target cell, but also implies that the second container handling vehicle is in the way of the first container handling vehicle entering the target cell given the movement constraints of the rail system.

[0034] Therefore, the present invention may be particularly advantageous when container delivery vehicles operate on rail systems, since these rail systems may be congested. A target cell may be defined as the cell to which the first container handling vehicle that receives the command should be moved. A number of container handling vehicles may form a queue, which may be common around a port cell. In such cases, the present invention may provide a more efficient and smoother movement of container handling vehicles, since when access to the port cell is free and the first container handling vehicle in the queue moves into the cell, the other vehicles can follow closely, thanks to the method disclosed herein. This would allow a first container handling vehicle to move towards a target cell while another vehicle is still partially within the target cell.

[0035] The vehicle control system of the first container handling vehicle may derive which portion of the proximity sensor system needs to be activated based on a command received by the first container handling vehicle from the central control system, which may typically be the portion of the proximity sensor system configured to make measurements in a direction in which the first container handling vehicle should be driven when commanded to reach the target cell. In another aspect, the central control system may include instructions in the data signal as to which portion of the proximity sensor system to activate. The vehicle control system may further receive instructions in the data signal as to an activation duration for the proximity sensor system, which may be determined depending on whether the first container handling vehicle is following the second container handling vehicle in a parallel direction or the second container handling vehicle is moving in an orthogonal direction. For example, it may be advantageous to keep the proximity sensor system activated to avoid a collision when the first container handling vehicle is following the second container handling vehicle.

[0036] In an embodiment, the predetermined distance may be measured from a side surface of the first container handling vehicle in the run direction. Preferably, the side surface may form part of a vertical plane parallel to the direction of one of the runway sets and tangent to the outermost lateral blocking extension of the container handling vehicle in the X and Y directions. The outermost lateral blocking extension may be defined as a physical part of the container handling vehicle that will restrict another container handling vehicle from passing the first container handling vehicle in an adjacent cell. Thus, elastic antennas, brushes and other deformable objects that do not present a physical barrier are not considered to form an outermost extension. However, it should be noted that the container handling vehicle may comprise a lateral extension that does not constitute a lateral blocking section, for example a container handling vehicle having a protruding section on one side may further comprise a complementary recessed section on the opposite side, or the protruding section may be arranged to extend above other container handling vehicles on the grid.

[0037] Thus, by defining the above-mentioned side surfaces, the proximity sensor system may advantageously be positioned at various locations on the container handling vehicle to have various distances relative to the side surfaces, which distance may be determined depending on the configuration of the container handling vehicle and its lateral outermost interference extension.

[0038] In an aspect, each container handling vehicle may have four side surfaces, the side surfaces comprising: a first side surface facing in a positive first direction, a second side surface facing in a negative first direction, a third side surface facing in a positive second direction, and a fourth side surface facing in a negative second direction, the first side surface, the second side surface, the third side surface, and the fourth side surface facing in a negative second direction, the positive and negative directions being opposite to each other; Equipped with The first side surface and the second side surface extend between the third side surface and the fourth side surface such that the side surfaces form a rectangular zone on a horizontal plane of the track system.

[0039] Thus, the rectangular zone of a container handling vehicle on a track system is the area occupied by a container handling vehicle or where the vehicle obstructs the entry of other vehicles. Areas can be defined on the grid where other container handling vehicles cannot pass, thus providing the central control system with an overview of whether a grid column is occupied by a container handling vehicle. Additionally, each side surface can define a lateral extent where measurements need to be made by the proximity sensor system.

[0040] The method may comprise transmitting a data signal from the central control unit to a vehicle control unit of the second container handling vehicle commanding the second container handling vehicle to move away from the target cell. The data signal to the second container handling vehicle may be transmitted before or after the data signal to the first container handling vehicle is transmitted. For example, the data signal to the second container handling vehicle may be transmitted in advance, but the second container handling vehicle is operating and in use at its current location and therefore has not yet moved upon the arrival of the first container handling vehicle, preventing access to the target cell.

[0041] The method can include transmitting a data signal from the central control unit to a vehicle control unit of the second container handling vehicle commanding the second cargo handling vehicle to move away from the target cell to another location on the rail system. The data signal commanding the second container handling vehicle to move away from the target cell can be a normal command with a new task, for example, to retrieve or deposit the container at another location in the grid.

[0042] The method may include transmitting a data signal from the central control unit to a vehicle control unit of the second container handling vehicle instructing the second container handling vehicle to move in a direction parallel to a direction between the target cell and the first container handling vehicle, such that the first container handling vehicle and the second container handling vehicle may move in parallel or the same direction.

[0043] The method may include continuously monitoring, using a proximity sensor system of the first container handling vehicle, to detect whether the second container handling vehicle is within a predetermined distance when the first container handling vehicle moves into the target cell. Thus, the first container handling vehicle may monitor whether the second container handling vehicle is stopping unexpectedly, so that the first container handling vehicle may stop moving on its own to avoid a collision. Thus, continuously monitoring may be advantageous when the container handling vehicles move in the same or parallel direction. Thus, a data signal sent to the first container handling vehicle may instruct the first container handling vehicle to continuously monitor a predetermined distance in its direction of movement.

[0044] In case the container handling vehicles move in parallel directions, the predetermined distance may be set to slightly exceed the length or width of the grid cell in the direction of movement, for example between 30 and 200 centimeters, or between 50 and 200 centimeters, depending on the direction of movement. However, the predetermined distance may vary depending on the speed of the container handling vehicles. The predetermined distance may also be set to slightly below the length or width of the grid cell in the direction of movement, which may be advantageous, for example, during congestion periods and when multiple container handling vehicles are queuing. However, the distance between the side surfaces of the first container handling vehicle and the second container handling vehicle when the first container handling vehicle is located on a grid cell adjacent to the target cell may also be taken into account.

[0045] The method may include transmitting a data signal from the central control unit to a vehicle control unit of the second container handling vehicle instructing the second container handling vehicle to move in a direction perpendicular to a direction between the target cell and the first container handling device.

[0046] Typically, when the container handling vehicles move in mutually orthogonal directions, the predefined distance may be set to be slightly more than the width of the rail, i.e. between 1 and 20 centimetres. Also, the data signal sent to the first container handling vehicle may instruct the first container handling vehicle to monitor the predefined distance only until the second container handling vehicle is no longer within the predefined distance. The data signal may further include details regarding the direction of movement of the second container handling vehicle, so that the vehicle control unit of the first container handling vehicle can determine which part of the proximity sensor system is required to monitor the predefined distance. However, the distance between the side surfaces of the first container handling vehicle and the second container handling vehicle when the first container handling vehicle is located on a grid cell adjacent to the target cell may also be taken into account.

[0047] The proximity sensor system of the first container handling vehicle may measure a predetermined distance from one of the side surfaces of the first container handling vehicle, where the predetermined distance is defined in the direction of the rail. Preferably, said side surface may form a portion of a vertical plane perpendicular to the plane defined by both rails, parallel to the direction of one of the rail sets, and tangent to a lateral outermost obstruction extent in the X and Y directions of the container handling vehicle, where the lateral outermost obstruction extent may be defined as a physical portion of the container handling vehicle that will restrict another container handling vehicle from passing the first container handling vehicle in an adjacent cell. Thus, elastic antennas, brushes and other deformable objects that do not present a physical barrier are not considered to form an outermost extent. However, it should be noted that a container handling vehicle may have a lateral extension that does not constitute a lateral obstruction section, for example a container handling vehicle having a protruding section on one side may further have a complementary recessed section on the opposite side, or the protruding section may be positioned on the grid to extend above other container handling vehicles.

[0048] Thus, by defining the above-mentioned side surfaces, the proximity sensor system may advantageously be positioned at various locations on the container handling vehicle to have various distances relative to the side surfaces, which may be determined by the configuration of the container handling vehicle and its lateral outermost interference extension.

[0049] The method may include determining, with the vehicle control unit, from which side surface of the first container handling vehicle the second container handling vehicle should be detected. Typically, the first container handling vehicle may monitor in its intended direction of travel. The central control unit may further provide the direction of travel of the second container handling vehicle such that the vehicle control unit may determine which part of the proximity sensor system to monitor.

[0050] The method may include transmitting a data signal from the central control unit to a vehicle control unit of the first container handling vehicle to define the predetermined distance. In an aspect, the present invention relates to an automated storage and retrieval system, the automated storage and retrieval system comprising: - a first set of parallel rails arranged in a horizontal plane and extending in a first direction, and a second set of parallel rails arranged in the horizontal plane and extending in a second direction perpendicular to the first direction; a rail system comprising rails, the first and second sets of rails forming a grid pattern in a horizontal plane comprising a plurality of adjacent grid cells; - a central control unit configured to receive, transmit, and process data signals of a plurality of container handling vehicles for handling storage containers of the automated storage and retrieval system, Each container handling vehicle, Vehicle body, a wheel assembly disposed within a vehicle body, the wheel assembly being configured to move the vehicle along the rail system in at least one of a first direction and a second direction; a vehicle control unit configured to receive, transmit, and process data signals of the central control unit; Equipped Central Control Unit Equipped with each of the plurality of container handling vehicles comprising a proximity sensor system configured to detect another container handling vehicle of the plurality of container handling vehicles and determine whether the other container handling vehicle is within a predetermined distance; The method comprises the steps of: - detecting that access of a first container handling vehicle to a target cell, the target cell being a grid cell of the plurality of grid cells, is obstructed by a second container handling vehicle; - transmitting a data signal from the central control unit to a vehicle control unit of the first container handling vehicle commanding the first container handling vehicle to move into the target cell if the second container handling vehicle is outside the predetermined distance range. The present invention is characterized in that it is composed of:

[0051] Alternatively, not all container handling vehicles of the automated storage and retrieval system may be equipped with proximity sensors. Only a portion of the container handling vehicles may be equipped with proximity sensors. This may be because only a certain portion of the container handling vehicles need to operate in congested areas, or because some of the container handling vehicles belong to a generation of prior art vehicles that do not require proximity sensors, and not all vehicles are being replaced.

[0052] The predetermined distance may be measured from a side surface of the container handling vehicle in the direction of the rail. Each container handling vehicle has four vertical side surfaces, the four side surfaces being: a first side surface facing in a positive first direction, a second side surface facing in a negative first direction, a third side surface facing in a positive second direction, and a fourth side surface facing in a negative second direction, where the positive and negative directions are opposite to each other; and The first and second side surfaces extend between the third and fourth side surfaces such that the side surfaces form a rectangular cross-section in a horizontal plane.

[0053] Thus, the rectangular cross section of a container handling vehicle on the track system can define areas on the grid that are occupied by the container handling vehicle or where other container handling vehicles cannot pass because the vehicle blocks the entry of other vehicles during travel constraints on the rail system. The rectangular cross section thus provides a centrally controlled overview of whether a grid column is occupied by a container handling vehicle. Additionally, each side surface may define a lateral extent of where the proximity sensor system needs to measure.

[0054] The proximity sensor system must have at least: - a first part sensor system facing outward from the first side surface in a positive first direction and capable of detecting another container handling vehicle within said predetermined distance from the first side surface; - a second part sensor system facing outward from the second side surface in a negative first direction and capable of detecting another container handling vehicle within said predetermined distance from the second side surface; - a third part sensor system facing outward from the third side surface in the positive second direction and capable of detecting another container handling vehicle within the predetermined distance from the third side surface; and - a fourth part sensor system facing outwardly from the fourth side surface in a negative second direction and capable of detecting another container handling vehicle within said predetermined distance from the fourth side surface; The present invention can include any one of the following:

[0055] Thus, a container handling vehicle may be equipped with only one, two, three or four part sensor systems. In some storage systems, it may be clear that the container handling vehicle only requires one part sensor system in a particular direction, and therefore it may be cheaper to provide the container handling vehicle with a minimum number of sensor systems. Similarly, some systems may require the container handling vehicle to be equipped with sensor systems in only two or three directions, and a corresponding number of part sensor systems are provided.

[0056] The proximity sensor system may comprise at least two proximity sensors, where each of the at least two proximity sensors is positioned to detect another container handling vehicle at a boundary of one of the side surfaces in the horizontal plane, and the at least two proximity sensors of the first container handling vehicle may thus detect whether the second container handling vehicle has moved away from the obstructing position in a direction perpendicular to the commanded direction in which the first container handling vehicle should move.

[0057] The proximity sensor may be any type of sensor known in the art, such as, for example, an optical sensor, a radar sensor, an acoustic sensor, a magnetic sensor, a capacitive sensor, or a combination thereof.

[0058] In other configurations, only one proximity sensor is located per part sensor system, but the one proximity sensor may be located to detect along a portion or the entire side surface, for example one sensor extending along the entire side surface. In some configurations, one proximity sensor may be located at a corner of the two side surfaces and may be positioned to detect another container handling vehicle facing outward from at least one of the two side surfaces, in which case the proximity sensor may be considered part of both two side proximity sensor systems, i.e. the two part sensor systems share one common proximity sensor.

[0059] The rectangular cross-section of either the first or second container handling vehicle may correspond to an integer number of grid cells. For example, both container handling vehicles may have rectangular cross-sections that correspond to only one grid cell, in which case the second container handling vehicle may at least partially cover the target cell. In another embodiment, any one of the container handling vehicles can have a rectangular cross-section that corresponds to an integer multiple of grid cells. For example, a first container handling vehicle can have a rectangular cross-section that corresponds to two complete grid cells, and a second container handling vehicle can have a rectangular cross-section that corresponds to only one grid cell. In this embodiment, the second container handling vehicle can block access to the target cell even if it only partially covers a cell adjacent to the target cell.

[0060] The rectangular cross-section of either the first or second container handling vehicle may correspond to more than one grid cell, for example, the first container handling vehicle may have a rectangular cross-section corresponding to only one grid cell and the second container handling vehicle may have a rectangular cross-section corresponding to 1 by 1.5 grid cells.

[0061] Based on the disclosure of the invention herein, it will be apparent to one of ordinary skill in the art that a system according to any of the above-mentioned aspects may be configured to perform a method according to any of the above-mentioned aspects.

[0062] In the following, numerous specific details are introduced, merely by way of example, to enable a thorough understanding of the claimed methods of operating an automated storage and retrieval system and embodiments of the automated storage and retrieval system. However, those skilled in the art will recognize that the embodiments may be practiced without one or more of the specific details, or with other components, systems, etc. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring aspects of the disclosed embodiments.

[0063] To facilitate an understanding of the invention, the following drawings are attached, purely by way of example, in which: [Brief description of the drawings]

[0064] [Figure 1] FIG. 1 is a perspective view of a grid of a prior art automated storage and retrieval system. [Figure 2a] FIG. 1 is a perspective view of a prior art container handling vehicle having a centrally located cavity for containing a storage container therein. [Figure 2b] FIG. 1 is a perspective view of a prior art container handling vehicle having a cantilever for containing a storage container thereunder. [Diagram 3] FIG. 1 is a top view of a prior art single rail grid. [Figure 4] FIG. 1 is a top view of a prior art double rail grid. [Diagram 5] FIG. 1 is a schematic diagram showing four vertical side surfaces formed by a container handling vehicle having irregular protrusions lying on a horizontal plane of a rail system. [Figure 6] FIG. 1 is a perspective view of a container handling vehicle, showing a side surface and a schematic of possible locations of a proximity sensor system. [Figure 7] FIG. 1 is a perspective view of a container handling vehicle, showing a side surface and a schematic of possible locations of a proximity sensor system. [Figure 8a]FIG. 2 is a side view of a container handling vehicle with a protruding section, showing generally the side surfaces present on said vehicle. [Figure 8b] FIG. 8b is a perspective view showing two container handling vehicles of the same type as shown in FIG. 8a operating on adjacent rows of grid cells. [Figure 9a] FIG. 2 is a perspective view of a container handling vehicle for delivery of containers, showing generally the side surfaces present on said vehicle. [Figure 9b] FIG. 1 is a perspective view showing a storage system with a cantilevered container handling vehicle operating on a grid rail system and a container handling vehicle operating on a lower rail system for container delivery. [Figure 10] FIG. 2 is a schematic top view of a rail system showing the protrusions and side surfaces formed by a number of different container handling vehicles. [Figure 11] 1 is a flow chart illustrating method steps for operating an automated storage and retrieval system. [Figure 12] FIG. 2 is a schematic top view of the rail system illustrating the steps of the method when the container handling vehicles are moving in the same direction. [Figure 13] FIG. 13 is a schematic top view of the rail system similar to FIG. 12 but showing the steps of the method when a second container handling vehicle occupies a cell adjacent to the target cell. [Figure 14] FIG. 13 is a schematic top view of the rail system similar to FIG. 12, but showing the steps of the method when a second container handling vehicle partially occupies the target cell. [Figure 15] FIG. 2 is a schematic top view of the rail system illustrating the steps of the method when the container handling vehicles are moving in mutually perpendicular directions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] In the drawings, like reference numerals are used to denote like parts, elements or features unless otherwise stated or implied from the context. In the following, embodiments of the invention will be considered in more detail, by way of example only, with reference to the accompanying drawings, in which it will be understood, however, that the drawings are not intended to limit the invention to the subject matter depicted therein.

[0066] The framework 100 of the automated storage and retrieval system 1 is constructed in accordance with the prior art framework 100 described above in relation to Figures 1-4, i.e. comprising a number of upright members 102 and a number of horizontal members 103 supported by the upright members 102, the framework 100 further comprising a rail system 108 of parallel rails 110, 111 in the X and Y directions arranged to straddle the storage columns 105 / grid columns 112. The horizontal area of ​​the grid columns 112, i.e. the area along the X and Y directions, may be defined by the distance between adjacent rails 110 and 111, respectively (see Figures 3 and 4).

[0067] In Figure 1, grid 104 is shown having a height of eight cells. However, it should be understood that grid 104 may in principle be any size grid. In particular, it should be understood that grid 104 may be significantly wider and / or longer and / or deeper than that disclosed in Figure 1. For example, grid 104 may have a horizontal extent greater than 700 x 700 grid cells and a depth greater than 12 grid cells.

[0068] The grey area in Fig. 5 represents the projection 6 in the horizontal plane of the irregularly shaped container handling vehicle 400 and the side surfaces 7, 8, 9, 10 tangent to the projection 6, which form a rectangular cross section 11 represented by solid lines, parallel to the first direction X and the second direction Y. Thus, the first side surface 7 and the second side surface 8 are parallel to the vertical plane V, as indicated by the dashed line, which is also parallel to the second direction Y, whereas the third side surface 9 and the fourth side surface 10 are parallel to the vertical plane V, as indicated by another dashed line perpendicular to the dashed line mentioned above, which is also parallel to the first direction X. The projection 6 indicates the outermost lateral obstruction extension of the container handling vehicle in the first direction X and the second direction Y, i.e. the outermost point of the container handling vehicle beyond which another vehicle cannot pass. As shown by this embodiment along a first positive direction X+, a predetermined distance D is measured from the first side surface 7, independent of the shape of the container handling vehicle. , it is necessary to take into account the distance from the sensors in the proximity sensor system 4 to the side surface 7 because the sensors cannot be physically positioned along the

[0069] As shown in Fig. 5, the proximity sensor system 4 is arranged to detect along the entire side surfaces 7, 8, 9, 10. Thus, the first side surface 7 faces towards a positive first direction X+, the second side surface 8 faces towards a negative first direction X-, the third side surface 9 faces towards a positive second direction Y+ and the fourth side surface 10 faces towards a negative second direction Y-. The negative directions are oriented opposite to their respective positive directions. The combined side surfaces 7, 8, 9, 10 form a rectangular cross section 11 in the horizontal plane P, so that the first side surface 7 and the second side surface 8 extend between the third side surface 9 and the fourth side surface 10 and vice versa.

[0070] 5, the detection directions of the proximity sensor system 4 are represented by arrows pointing outwards from the side surfaces 7, 8, 9, 10. Thus, the first part sensor system 4X+ is positioned to detect along the first side surface 7 in a positive first direction X+, the second part sensor system 4X- is positioned to detect along the second side surface 8 in a negative first direction X-, the third part sensor system 4Y+ is positioned to detect along the third side surface 9 in a positive second direction Y+, and the fourth part sensor system 4Y is positioned to detect along the fourth side surface 10 in a negative second direction Y-.

[0071] FIG. 6 is a perspective view of a container handling vehicle 101 showing how the side surfaces 7, 8, 9, 10 can be defined on this type of container handling vehicle 101. The dashed lines represent the horizontal and vertical borders of the side surfaces 7, 8, 9, 10, which are parallel to the respective vertical planes V and the respective first and second directions X and Y. Thus, in this embodiment, the side surfaces 7, 8, 9, 10 generally coincide with the physical side surfaces of the external housing of the container handling vehicle 101. However, as will be appreciated by those skilled in the art, this may not always be the case, especially in the case of irregularly shaped container handling vehicles 400. A coordinate system is inserted in FIG. 6 to show how the second side surface 8 faces towards the first negative direction X- and how the fourth side surface 10 faces towards the negative second direction Y-. However, it should be noted that the coordinates and orientation of the container handling vehicle 101 in FIG. 6 are merely examples to show how the side surfaces 7, 8, 9, 10 may be defined on the container handling vehicle 101. The definition of which side is which is determined by the orientation of the container handling vehicle 101 when placed on the grid 104, which gives a frame of reference as to what are the positive and negative first direction X, second direction Y, and third direction Z. Four sensors 17 of the proximity sensor system 4 are illustrated, each one being placed in the upper corner of each side surface 8, 10 of the external housing of the container handling vehicle 101. As will be apparent, similar sensors, not shown in FIG. 6, may be found on the sides 7 and 9 of the container handling vehicle 101. Advantageously, the sensors 17 are placed near the border of the side surfaces 7, 8, 9, 10, because this allows the sensors 17 to detect the presence of another container handling vehicle moving parallel to said side surfaces.

[0072] In an alternative embodiment of the invention, the proximity sensor is located on the top most surface of the container handling vehicle. In this embodiment, a single proximity sensor may be used. This proximity sensor may be tilted or rotated to cover the entire 360° area around the container handling vehicle.

[0073] In another embodiment of the present invention, four proximity sensors are mounted on the topmost side of the container handling vehicle. The four sensors may be positioned on the surface. By using four sensors, it is possible to cover the entire 360° area around the container handling vehicle without having to move the sensors. Each sensor covers one side of the container handling vehicle. The first proximity sensor faces outward in a positive first direction and is capable of detecting another container handling vehicle within the predetermined distance from the first side surface, the second proximity sensor faces outward in a negative first direction and is capable of detecting another container handling vehicle within the predetermined distance from the second side surface, the third proximity sensor faces outward in a positive second direction and is capable of detecting another container handling vehicle within the predetermined distance from the third side surface, and the fourth proximity sensor faces outward in a negative second direction and is capable of detecting another container handling vehicle within the predetermined distance from the fourth side surface.

[0074] FIG. 7 is a perspective view of a container handling vehicle 201 showing how the side surfaces 7, 8, 9, 10 can be formed on this type of container handling vehicle 201. It should be noted that in this embodiment, the side surfaces 7, 8, 9, 10 do not generally coincide with the external housing of the container handling vehicle 201, except for the second side surface 8. Due to the cantilevered structure of this container handling vehicle 201, the outermost portion of the cantilever 202 defines the third side surface 9, because the third side surface extends over the grid cell 122 and prevents the grid cell 122 from being occupied by other container handling vehicles. Thus, in addition, the fourth side surface 10 extends from the edge of the cantilever 202 to the second side surface 8. Three sensors 17 of the proximity sensor system 4 are illustrated as being respectively arranged in the upper corners of the second and third side surfaces 8, 9 of the external housing of the container handling vehicle 201, whereas the fourth sensor 17 is arranged near the edge of the cantilever 202. As will be apparent, similar sensors 17 may be found on the sides 7 and 9, which are not fully shown in FIG. 7, where they are also arranged in the outermost edge of the cantilever 202, such that they point towards the positive first direction X+. Advantageously, the sensor 17 is arranged near the border of the side surfaces 7, 8, 9, 10, because this allows the sensor 17 to detect the presence of another container handling vehicle moving parallel to said side surfaces 7, 8, 9, 10.

[0075] In an alternative embodiment of the invention, the proximity sensor is located on the top most surface of the container handling vehicle. In this embodiment, a single proximity sensor may be used. This proximity sensor may be tilted or rotated to cover the entire 360° area around the container handling vehicle.

[0076] In another embodiment of the invention, four proximity sensors may be positioned on the top most surface of the container handling vehicle. By using four sensors, it is possible to cover the entire 360° area around the container handling vehicle without having to move the sensors. Each sensor covers one side of the container handling vehicle. The first proximity sensor faces outward in a positive first direction and can detect another container handling vehicle within the predetermined distance from the first side surface, the second proximity sensor faces outward in a negative first direction and can detect another container handling vehicle within the predetermined distance from the second side surface, the third proximity sensor faces outward in a positive second direction and can detect another container handling vehicle within the predetermined distance from the third side surface, and the fourth proximity sensor faces outward in a negative second direction and can detect another container handling vehicle within the predetermined distance from the fourth side surface.

[0077] FIG. 8 illustrates the horizontal orientation of the grid columns 112 or grid cells 122. 8a shows another type of container handling vehicle 301 having a contact area with respect to the rail system 108 with a horizontal extent equal to the area of ​​the container handling vehicle 301. The container handling vehicle 301 further comprises a protruding section 302 as shown in FIG. 8a, which extends laterally beyond the contact area of ​​the container handling vehicle 301 and into an adjacent grid cell 122 when the container handling vehicle 301 is positioned on the grid cell 122. The container handling vehicle 301 comprises a vehicle body 301a, a drive means 301b for driving in a first direction X and a drive means 301c for driving in a second direction Y. Although the drive means 301c in the second direction Y is not shown in the side view of FIG. 8a, the drive means 301c can be seen in FIG. 8b and is arranged similarly to the drive means 301b in the first direction X.

[0078] However, the protruding section 302 does not prevent another container handling vehicle 301 from moving over an adjacent grid cell 122, i.e., over a grid cell 122 into which the protruding section 302 of a first vehicle extends. To achieve this, the container handling vehicles 301 each include a recessed section 303 located opposite the protruding section 302, which can receive the protruding section 302 of the other vehicle 301 as the container handling vehicle 301 passes over the adjacent grid cell 122. The recessed section 303 can have a shape that is complementary to the shape of the protruding section 302 and can extend the full width or length of the container handling vehicle 301, thereby allowing the vehicles 301 to pass each other over adjacent grid cells 122. When the vehicles 301 are operating on the rail system 108, the recessed section 303 of each container handling vehicle 301 can accommodate the protruding section 302 of the other container handling vehicle 301 as the vehicle 301 passes over an adjacent grid cell 122, thereby enabling the container handling vehicles 301 to move along adjacent rows of grid cells as shown in FIG. 8b.

[0079] The container handling vehicle 301 of Figures 8a and 8b is included herein to illustrate that the protruding section 301 does not necessarily block access to adjacent grid cells 122, depending on the shape of the container handling vehicle. It will therefore be apparent to one skilled in the art that other variations of container handling vehicles, having protrusions or even not having corresponding recesses, may be employed on the rail system 108 such that the protrusions do not function to prevent other container handling vehicles from accessing adjacent grid cells 122. Thus, the difference between the container handling vehicles of Figures 7 and 8, both of which include portions that extend over adjacent grid cells 122, is that only the container handling vehicle 201 of Figure 7 has a side surface 9 defined from an edge of the cantilever 202, in contrast to the container handling vehicle 301 of Figure 8, in which the first side surface 7 is not defined by the outermost edge of the protruding section 302.

[0080] Figure 9 shows another embodiment of a container handling vehicle according to the present invention, where a container handling vehicle 601 for delivery of containers is shown in Figure 9a, which is associated with the automated storage and retrieval system 1 in Figure 9b.

[0081] As shown in Fig. 9a, a container delivery vehicle 601 is arranged to retrieve a storage container 106 in a top-down manner and thus comprises a container carrier 602 arranged above a vehicle body 601a to retrieve the storage container 106. The container delivery vehicle 601 comprises a drive means 301b in a first direction X and a drive means 301c in a second direction Y, similar to the drive means of the other container handling vehicles 101, 201, 301 mentioned above. As in the case of the other container handling vehicles, the container delivery vehicle 601 For this purpose side surfaces 7, 8, 9, 10 are defined, where the second side surface 8 and the fourth side surface 10 can be seen in figure 9a. Furthermore possible locations of proximity sensors are also shown.

[0082] 9b shows the container delivery vehicle 601 operating on rail system 108' below the rail system 108 of the storage grid 104. The delivery rail system 50 may be configured in the same or similar manner as the rail system 108 for the container handling vehicles 200, 300.

[0083] The container handling vehicle 201 according to the embodiment of FIG. 2b is shown as operating on the rail system 108 of the storage grid 104. However, as will be clear to those skilled in the art, any kind of container handling vehicle 101, 201, 301 may be operated on the rail system 108 of the grid, for example according to the embodiment shown in FIGS. 6-8. Thus, the container handling vehicle 201 may lower the lower storage container to a container delivery vehicle 601 operated on the lower rail system 108'. The container delivery vehicle 601 is arranged to deliver the storage container 106 to an access point (not shown), typically at the periphery of the rail system 108, where the storage container 106 may be picked up. Although not shown here, the lower rail system 108' typically comprises a large number of container delivery vehicles 601, which may cause congestion and queuing problems because the container delivery vehicles 601 move between the cells below the port columns and the access points on the periphery of the lower rail system 108'. The invention therefore advantageously applies to a rail system 108 ′ comprising container delivery vehicles 601 in a similar manner as for the container handling vehicles 101 , 201 , 301 of the rail system 108 of the grid 104 .

[0084] FIG. 10 shows the rectangular cross-section 11 formed by the protrusions 6, side surfaces 7, 8, 9, 10 on the rail system, as well as a number of different examples of container handling vehicles. The rectangular cross-section 11 labeled A may be, for example, from the container handling vehicle 101 of FIG. 2a, FIG. 6, or FIG. 9, because the rectangular cross-section 11 formed by its side surfaces is equal to the lateral area defined by the grid cell 122. The rectangular cross-section 11 labeled B may be, for example, from a container handling vehicle having some similarities to that shown in FIG. 2a, with an area defined by a grid cell 122 of 1 (X direction) by 1.5 (Y direction), but where one side wall of the vehicle is enlarged and occupies half the area of ​​the grid cell 122. The rectangular cross-section 11 labeled C may be a rectangular cross-section of a container handling vehicle 400 with irregular protrusions, similar to the container handling vehicle of the example embodiment of FIG. 5. The rectangular cross-section 11 labeled D may be, for example, from the container handling vehicle 201 of Figure 2b or Figure 7. However, it is also contemplated that a container handling vehicle similar to that of Figure 2a, having a lateral area corresponding to two grid cells 122 and capable of simultaneously lifting two storage containers 106 from adjacent grid cells 122, may also form a rectangular cross-section 11 like the rectangular cross-section labeled D. Many further variations of container handling vehicles are contemplated, as will be apparent to those skilled in the art based on the disclosure of the invention herein.

[0085] 11 is a flow diagram illustrating generally the steps of a method for operating the automated storage and retrieval system 1. The method generally begins with step 700, in which the central control unit 15 detects a collision on a grid cell 122 by two container handling vehicles 2, 3. The container handling vehicle that is on route to the target cell 12 is referred to as the first container handling vehicle 2, and the container handling vehicle that blocks the first container handling vehicle 2's access to the target cell 12 is referred to as the second container handling vehicle 3. The target cell may typically be a grid cell 122 on the rail system 108, 108' where the container handling vehicle has received a command from the central control unit 15 to move. In a next step, the first container handling vehicle 2 moves to the grid cell 122 adjacent to its target cell 12 and receives a data signal from the central control unit 15, which the first container handling vehicle 2 processes in its vehicle control unit 14. The data signal comprises a command to activate the proximity sensor system 4 of the first container handling device 2, i.e. to start monitoring another container handling vehicle in the direction of the target cell 12 that coincides with its direction of movement. The data signal may further comprise the specification of a predefined distance D where the first container handling vehicle 2 should detect a second container handling vehicle 3 and where the first container handling vehicle 2 should move into the target cell 12 when the second container handling vehicle 3 moves out of said distance D. Another data signal is sent from the central control unit 15 to the vehicle control unit 14 of the second container handling vehicle 3 instructing the second container handling vehicle 3 to move away from the target cell 12. In some embodiments, the second container handling vehicle 3 may have already received a command to move away from the target cell 12 before the first container handling vehicle 2 receives the command to activate its proximity sensor system 4 and moves, but now the second container handling vehicle 3 has not yet moved. The reason may be, for example, that the second container handling vehicle 3 is being used to lower or lift a storage container 106, etc. Thus, the data signal from the central control unit to the first container handling vehicle 2 is indicated by step 710, and the activation of its proximity sensor system 4 is indicated by step 720. In either case, the second container handling vehicle 3 is moving away from its obstructed position in the target cell 12, as indicated by step 730.The vehicle control unit 14 of the first container handling vehicle 2 continuously monitors the data from its proximity sensor system 4, and when the object, i.e. the second container handling vehicle 3, is no longer within the predetermined distance D, the vehicle control unit 14 controls the first container handling vehicle 2 to move into the target cell 12, as indicated by step 740. Depending on the direction of movement of the second container handling vehicle 3 relative to the first container handling vehicle 3, the vehicle control unit 14 can continuously monitor whether the second container handling vehicle 3 is within the predetermined distance during the movement of the first container handling vehicle 2.

[0086] In the following, with reference to Figures 12-15, various steps of a method of operating an automated storage and retrieval system are illustrated according to the invention. To illustrate these steps, a schematic rail system and two container handling vehicles of one type of container handling vehicle 2, 3 are used throughout Figures 12-15. The container handling vehicles 2, 3 illustrated in Figures 12-15 comprise a container receiving space 13 having a rectangular cross section 11 equal to a 1x1.5 grid cell (i.e. 1x1.5) as described in connection with part B of Figure 10 and arranged on one side of the vehicle body. Although the container handling vehicles 2, 3 may further comprise a proximity sensor system 4 such as the proximity sensor system shown in Figures 6-9, in Figures 12-15 only one activated sensor 17 is shown, i.e. the sensor monitoring whether a second container handling vehicle 3 is within a predetermined distance D. However, the remaining sensors 17 may be in an activated state during the execution of the method.

[0087] 12 is a schematic top view of the rail system 108 illustrating the steps of the method in which, at the start of the method, a first container handling vehicle 2 and a second container handling vehicle 3 are positioned over adjacent grid cells 122, as shown in part A by the central control unit 15 sending data signals to each of the container handling vehicles 2, 3. The second container handling vehicle 3 is shown covering the entire target cell 12 and is further oriented to place its container receiving space 13 over the target cell 12. Such a starting point shown in Figure 12 may be common around ports, where a target cell 12 is located above the port columns 19, 20 through which storage containers 106 are dropped off and picked up. Thus, a first container handling vehicle 2 activates its proximity sensor system 4, represented by black dot 17, and continuously monitors a predetermined distance D during its journey into the target cell 12 to avoid a collision with a second container handling vehicle 3.

[0088] In part B of Figure 12, the second container handling vehicle 3 is moving as indicated by the arrow such that its position straddles two grid cells 122. The proximity sensor system 4 of the first container handling vehicle 2 monitors the presence of the second container handling vehicle 3 within a predetermined distance D which may typically be set to be 2m when the container handling vehicles 2, 3 are moving in parallel.

[0089] Thus, part C of Fig. 12 shows the first container handling vehicle 2 after detecting the absence of the second container handling vehicle 3 within a predetermined distance D, and both container handling vehicles 2, 3 are moving across the rail system 108. Thus, the proximity sensor system 4 of the first container handling vehicle 2 can continuously monitor in the first positive direction X+, for example as to whether the second container handling vehicle 3 has stopped unexpectedly, in order to avoid a collision. It should be noted that when the first container handling vehicle 2 starts to move, the second container handling vehicle 3 is partially within the target cell 12.

[0090] Part D of Figure 12 shows the end result of the method, where the first container handling vehicle 2 has moved over the target cell 12 and the second container handling vehicle 3 has moved to a new position on the rail system 108. Typically, the new position for the second container handling vehicle 3 may be associated with a new task, such as retrieving or depositing a storage container 106 anywhere in the grid 104.

[0091] FIG. 13 is a schematic top view of the rail system 108 illustrating the steps of the method, in which a first container handling vehicle 2 is located on a grid cell 122 adjacent to its target cell 12 that is not occupied, but a second container handling vehicle 3 blocks access to the target cell 12 due to the size and thus the rectangular cross section 11 of the first container handling vehicle 2. The steps illustrated by parts A-B of FIG. 13 are essentially the same as those of FIG. 12, but only the sensors 17 in the corners of the first container handling vehicle 2 that are closest to the second container handling vehicle 3 need to be activated. The central control unit 14 can transmit the movement direction and position for the second container handling vehicle 3, so that the vehicle control unit 14 of the first container handling vehicle 2 can determine which sensors need to be activated to monitor the presence of the second container handling vehicle 3 within a predetermined distance. Alternatively, the central control unit 15 can give a direct command to the first container handling vehicle 2 as to which sensors to activate.

[0092] Figure 14 is a schematic top view of the rail system 108 illustrating the steps of the method in which a first container handling vehicle 2 is located on a grid cell 122 adjacent its target cell 12 which is partially occupied by a second container handling vehicle 3 due to different orientations of the two vehicles 2, 3 on the rail system 108. The steps illustrated by portion AB in Figure 13 are essentially the same as those in Figure 14.

[0093] FIG. 15 is a schematic top view of the rail system 108 and illustrates a method step, where the first container handling vehicle 2 and the second container handling vehicle 3 are connected to each other, similar to the starting point of the method of FIG. In the first step, the second container handling vehicle 3 is initially located on the adjacent grid cell 122. However, in contrast to the step of FIG. 12, as shown in part B of FIG. 15, the second container handling vehicle 3 moves in a direction perpendicular to the direction in which the first container handling vehicle 2 should move. Thus, the sensor 17 of the first container handling vehicle 2, which is located in the corner of the moving direction of the second container handling vehicle 3, is activated. Furthermore, the predetermined distance D at which the second container handling vehicle 3 should be detected by the proximity sensor system 4 may be less than 2 meters, for example 10 centimeters. The reason is that it is only necessary to detect when the second container handling vehicle 3 passes the corner. The vehicle control unit 14 of the first container handling vehicle 2 can receive information about the predetermined distance D and which sensor should be activated, or the vehicle control unit 14 can determine the distance and the sensor to be activated by receiving information about the moving direction of the second container handling vehicle 3 from the central control unit 15. When the sensor 17 of the first container handling vehicle 2 detects no obstruction, said container handling vehicle 2 can move into the target cell 12. In prior art implementations of the method shown in Figure 15, the central control unit 15 would not know if the target cell 12 was free unless the second container handling vehicle 3 had moved at least to the position shown in part D of Figure 15, and would therefore have to wait an excessive amount of time for the first container handling device 3 to move into the target cell 12. Thus, the method steps of Figure 15 clearly illustrate the time-saving aspect of the present invention.

[0094] The predetermined distance D may be dynamically adapted to suit the speed at which the container handling vehicle is traveling. The container handling vehicle is set to have a default predetermined distance D for a given speed. The container handling vehicle itself will adapt the distance D to the speed at which the container handling vehicle is traveling.

[0095] In the above description, various aspects of the automated storage and retrieval system and method of operating the system according to the present invention have been described with reference to exemplary embodiments. However, this description is not intended to be construed in a limiting sense. Various modifications and variations of the exemplary embodiments, as well as other embodiments of the system and method that are apparent to those skilled in the art, are deemed to be within the scope of the present invention as defined by the following claims. [Explanation of symbols]

[0096] 1 Storage and Retrieval System 2. First container handling vehicle 3. Second container handling vehicle 4. Proximity Sensor System D. Predetermined distance 5 Side Surface 6. First container handling vehicle protrusion 7 First Side Surface 8 Second Side Surface 9 Third Side Surface 10 Fourth Side Surface 11 Rectangular extension 12 Target Cell 13 Container receiving space 14 Vehicle Control Unit 15 Central Control Unit 16 Data Signals 17 Proximity Sensor 19 Port Column 20 Port Column 100 Frame structure 101 Container handling vehicles 101a Vehicle body of container handling vehicle 101 101b Driving means in a first direction (X) 101c Driving means in the second direction (Y) 102 Upright members of frame structures 103 Horizontal members of frame structures 104 Grid 105 Storage Column 106 Storage Container 106' Specific location of storage container 107 Stack 108 Rail System 108' Rail system for delivery vehicles 110 Parallel rails in the first direction (X) 110a: the first rail of the adjacent rails 11 110b the second rail of the adjacent rail 11 111 Parallel rail in the second direction (Y) 111a: the first rail of the adjacent rails 12 111b the second rail of the adjacent rail 12 112 Grid Column 115 Grid Opening 122 Footprint / Grid Cell / Storage Cell 201 Cantilevered container handling vehicle 201a Vehicle body of cantilevered container handling vehicle 201 201b Drive means in a first direction (X) of the cantilevered container handling vehicle 201c Drive means in the second direction (Y) of the cantilevered container handling vehicle 202 Cantilever Section 301 Container handling vehicles with protruding sections 301a Container handling vehicle body 301b Drive means in the first direction (X) of the container handling vehicle with protruding section 301c Drive means in the second direction (Y) of the container handling vehicle with the protruding section 302 protruding section 303 Recessed Section 400 Irregular shaped container handling vehicles 601 Remotely Operated Delivery Vehicles 602 Delivery vehicle 601 container carrier 700 The control unit detects the collision 710 Command to prepare for movement is sent 720 First vehicle activates sensor system 730 The second vehicle moves away from the target cell 740 The first vehicle moves into the target cell X First Direction X- Negative first direction X+ positive first direction Y Second Direction Y+ positive second direction Y- Negative second direction Z third direction P horizontal plane P' the horizontal plane of the delivery vehicle rail system 108' V vertical plane D. Predetermined distance

Claims

1. A method of operating an automated storage and retrieval system (1), comprising the steps of: The automated storage and retrieval system (1), a rail system (108, 108') comprising a first set of parallel rails (110) arranged in a horizontal plane (P, P') and extending in a first direction (X) and a second set of parallel rails (111) arranged in said horizontal plane (P, P') and extending in a second direction (Y) perpendicular to said first direction (X), wherein said first set of rails (110) and said second set of rails (111) form a grid pattern in said horizontal plane (P, P') comprising a plurality of adjacent grid cells (122); a central control unit (14) configured to receive, transmit and process data signals of a plurality of container handling vehicles (2, 3) for handling storage containers (106) of the automated storage and retrieval system (1), Each container handling vehicle (2, 3) A vehicle body (101a, 201a, 301a, 601a), a wheel assembly (101b, 101c, 201b, 201c, 301b, 301c, 601b, 601c) provided in the vehicle body (101a, 201a, 301a, 601a), the wheel assembly (101b, 101c, 201b, 201c, 301b, 301c, 601b, 601c) configured to move the vehicle (2, 3) along the rail system (108, 108') in both the first direction (X) and the second direction (Y); a vehicle control unit (15) configured to receive data signals from the central control unit (14), transmit data signals to the central control unit (14), and process the data signals of the central control unit (14); a proximity sensor system (4) configured to detect another container handling vehicle (2, 3) of the plurality of container handling vehicles (2, 3) and determine whether the other container handling vehicle is within a predetermined distance (D); Equipped A central control unit (14) Equipped with The method further comprising: detecting, using the central control unit (14), that access of a first container handling vehicle (2) to a target cell (12), the target cell being one of the plurality of grid cells, is being blocked by a second container handling vehicle (2); sending a data signal (16) from the central control unit (14) to the vehicle control unit (15) of the first container handling vehicle (2) commanding the first container handling vehicle (2) to move into the target cell (12) if the second container handling vehicle (3) is outside the predetermined distance (D); Including, method.

2. sending a data signal (16) from the central control unit (14) to the vehicle control unit (15) of the second container handling vehicle (3) commanding the second container handling vehicle (3) to move away from the target cell (12); The method of claim 1 , comprising:

3. Another section of the rail system (108, 108') away from the target cell (12) sending a data signal (16) from the central control unit (14) to the vehicle control unit (15) of the second container handling vehicle (3) commanding the second cargo handling vehicle (3) to move to a container handling station; The method of claim 2 , comprising:

4. transmitting a data signal (16) from the central control unit (14) to the vehicle control unit (15) of the second container handling vehicle (3) commanding the second container handling vehicle (3) to move in a direction (X,Y) parallel to a direction (X,Y) between the target cell (12) and the first container handling vehicle (2); The method of claim 2 or 3, comprising:

5. continuously monitoring, using the proximity sensor system (4) of the first container handling vehicle (2) as the first container handling vehicle (2) moves into the target cell (12), to detect whether the second container handling vehicle (3) is within a predetermined distance (D); The method of claim 4 , comprising:

6. sending a data signal (16) from the central control unit (14) to the vehicle control unit (15) of the second container handling vehicle (3) commanding the second container handling vehicle (3) to move in a direction (X,Y) perpendicular to a direction (X,Y) between the target cell (12) and the first container handling device (2); The method of claim 2 or 3, comprising:

7. the proximity sensor system (4) of the first container handling vehicle (2) measuring the predetermined distance (D) from one of a plurality of side surfaces (7, 8, 9, 10) of the first container handling vehicle (2); The predetermined distance (D) is defined in the direction (X, Y) of the rails (110, 111); 7. The method according to any one of claims 1 to 6.

8. determining, using said vehicle control unit (15), from which side surface (7, 8, 9, 10) of said first container handling vehicle (2) said second container handling vehicle (3) should be detected; The method of claim 7, comprising:

9. transmitting a data signal (16) from said central control unit (14) to said vehicle control unit (15) of said first container handling vehicle (2) to define said predetermined distance (D); The method according to any one of claims 1 to 8, comprising:

10. An automated storage and retrieval system (1), comprising: a rail system (108, 108') comprising a first set of parallel rails (110) arranged in a horizontal plane (P, P') and extending in a first direction (X) and a second set of parallel rails (111) arranged in said horizontal plane (P, P') and extending in a second direction (Y) perpendicular to said first direction (X), wherein said first set of rails (110) and said second set of rails (111) form a grid pattern in said horizontal plane (P, P') comprising a plurality of adjacent grid cells (122); receiving, transmitting and processing data signals of a plurality of container handling vehicles (2, 3) for handling the storage containers (106) of the automated storage and retrieval system (1); A central control unit (14) comprising: Each container handling vehicle (2, 3) Vehicle body (101a, 201a, 301a, 601a), a wheel assembly (01b, 101c, 201b, 201c, 301b, 301c, 601b, 601c) provided in the vehicle body (101a, 201a, 301a, 601a), wherein the wheel assembly (18) is configured to move the vehicle (2, 3) along the rail system (108, 108') in at least one of the first direction (X) and the second direction (Y); a vehicle control unit (15) configured to receive, transmit and process data signals of said central control unit (14); Equipped with a central control unit (14), each of said plurality of container handling vehicles (2, 3) comprising a proximity sensor system (4) configured to detect another container handling vehicle (2, 3) of said plurality of container handling vehicles (2, 3) and determine whether said another container handling vehicle is within a predetermined distance (D); In an automatic storage and retrieval system (1), The central control unit (14) detecting that access of a first container handling vehicle (2) to a target cell (12), the target cell being one of the plurality of grid cells, is obstructed by a second container handling vehicle (2); sending a data signal (16) from the central control unit (14) to the vehicle control unit (15) of the first container handling vehicle (2) commanding the first container handling vehicle (2) to move into the target cell (12) if the second container handling vehicle (3) is outside the predetermined distance (D); The automated storage and retrieval system (1) is characterized by being configured as follows.

11. 11. The system according to claim 10, wherein the predetermined distance (D) is measured from a side surface (5) of a container handling vehicle (2) in the direction (X, Y) of the rails (110, 111).

12. Each container handling vehicle (2, 3) has four vertical side surfaces (7, 8, 9, 10); The four side surfaces (7, 8, 9, 10) are arranged in a positive and negative direction opposite to each other, a first side surface (7) facing in a positive first direction (X+); a second side surface (8) facing in the negative first direction (X-); a third side surface (9) facing in the positive second direction (Y+); a fourth side surface (10) facing in the negative second direction (Y-) and said first side surface (7) and said second side surface (8) extend between said third side surface (9) and said fourth side surface (10) such that said side surfaces (7, 8, 9, 10) form a rectangular cross-section (11) in a horizontal plane; The system of claim 11.

13. The proximity sensor system (4) a first part sensor system (4X+) capable of detecting another container handling vehicle (2, 3) facing outward from said first side surface (7) in said positive first direction (X+) and within said predetermined distance (D) from said first side surface (7); Facing outward from said second side surface (8) in said negative first direction (X-). a second part sensor system (4X-) capable of detecting another container handling vehicle (2, 3) within said predetermined distance (D) from said second side surface (8); a third part sensor system (4Y+) facing outward from said third side surface (9) in said positive second direction (Y+) and capable of detecting another container handling vehicle (2, 3) within said predetermined distance (D) from said third side surface (9); a fourth part sensor system (4Y-) facing outward from said fourth side surface in said negative second direction (Y-) and capable of detecting another container handling vehicle (2, 3) within said predetermined distance (D) from said fourth side surface (10); At least one of the following is provided: A system (1) according to claim 12.

14. said proximity sensor system comprising at least two proximity sensors (17); each of said at least two proximity sensors (17) is arranged to detect another container handling vehicle at a boundary of any one of said side surfaces (7, 8, 9, 10) in said horizontal plane (P); A system (1) according to claim 12.

15. the rectangular cross section (11) of either the first container handling vehicle (2) or the second container handling vehicle (3) corresponds to an integer multiple of a grid cell (122); A system (1) according to any one of claims 12 to 14.

16. the rectangular cross-section (11) of either the first container handling vehicle (2) or the second container handling vehicle (3) corresponds to two or more grid cells (122); A system (1) according to any one of claims 12 to 15.

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