Cargo handling devices

Abstract

A cargo handling device designed to operate on top of a cube-shaped automated storage and retrieval system (ASRS). The cargo handling device features two wireless network interfaces that can be coupled to a single wireless connection with a wireless access point. When in use, one of the wireless network interfaces can be used to connect to a further wireless access point. Data can then flow from the ASRS to the cargo handling device via the further wireless access point. The coupled connection can then be reconfigured to connect via the further wireless access point.

Description

Technical Field

[0001] The present disclosure relates to a method of operating a load handling device, and more particularly, to a method of operating a load handling device in a storage and retrieval system.

Background Art

[0002] Grid-based automated storage and retrieval systems are well known in the art. In such systems, a plurality of robotic load handlers operate on a horizontal grid structure under which a plurality of containers arranged in a plurality of stacks are received. Containers are used to hold products, and load handlers are adapted to remove a container from one of the plurality of stacks and place the container into one of the stacks. Load handlers can be routed in an autonomous (or semi-autonomous) manner on the grid, but a wireless communication system is required to send commands to the load handlers and to enable each of the load handlers to communicate with a management system. The apparatus, method, system, and computer program according to the claims are intended to provide improvements to a communication system for use in an automated retrieval and storage system using a fleet of robotic load handlers.

Summary of the Invention

[0003] A first aspect of the present disclosure provides a method for operating a cargo handling device in a storage and retrieval system, the method comprising: a) establishing a first wireless connection between a cargo handling device and a first wireless access point, wherein i) the cargo handling device comprises a first wireless interface and a second wireless interface, ii) the first wireless connection is a bonded connection used to transfer data between the storage and retrieval system and the cargo handling device via the first wireless access point, iii) both the first and second wireless interfaces are bonded to the first connection, the first wireless interface being the active interface and the second wireless interface being the backup interface, b) establishing a second wireless connection between a cargo handling device and a second wireless access point when one or more conditions are met, the method comprising: iv) the second wireless interface being removed from the bonded first wireless connection, and v) the second wireless connection being established between the second wireless interface of the cargo handling device and the second wireless access point.

[0004] Data may be transferred between the storage system and the cargo handling device via a second wireless access point and a second wireless connection. Furthermore, in this case, no data may be transferred between the storage system and the cargo handling device via the first wireless access point. Subsequently, the first wireless interface may terminate its wireless connection with the first wireless access point and establish a wireless connection with the second wireless access point. Both the first and second wireless interfaces may be connected via a coupled connection, where the second wireless interface is the active interface and the first wireless interface is the backup interface. The coupled wireless connection may be reconfigured such that the first wireless interface is the active interface and the second wireless interface is the backup interface, and thus data is transferred between the storage system and the cargo handling device via the second wireless connection and the first wireless interface.

[0005] This method has been shown to significantly reduce the time required for a cargo handling device to hand over from one wireless access point to another. Using conventional WiFi roaming technologies (e.g., those described in IEEE 802.11r,k,v), WiFi handovers have been shown to take up to 1200ms. In contrast, this method enables WiFi handovers in up to 200ms. Such reductions are crucial in low-latency applications, such as the operation of cargo handling devices in ASRSs. Furthermore, this method provides improved resilience compared to known methods.

[0006] The received signal strength of the first wireless access point and / or the received signal strength of the second wireless access point may be used as a condition to establish the second wireless connection in step b). Furthermore, or alternatively, the error rate in the first wireless connection may be used as a condition to establish the second wireless connection in step b).

[0007] According to a second aspect of the present disclosure, a cargo handling device for use in a storage system is provided, the cargo handling device comprising a first network interface and a second network interface, and the cargo handling device is configured to perform the method described above when in use. The cargo handling device may further comprise a wheel assembly arranged to move selectively in one of two orthogonal directions, and a container lifting device arranged to lift a container from one of a plurality of stacks into the cargo handling device when in use.

[0008] A third aspect of the present disclosure provides a storage system comprising: a first set of parallel rails extending in the X direction in a substantially horizontal plane to form a grid pattern comprising a plurality of grid spaces; a second set of parallel rails extending in the Y direction traversing the first set; a plurality of stacks of containers located below the rails and arranged such that each stack is located within the footprint of a single grid space; and at least one loading / unloading device as described in claim 9 or 10, the at least one loading / unloading device positioned above the stacks on the rails to transport containers and positioned to move selectively in the X and / or Y directions. The at least one loading / unloading device may have a footprint that occupies only a single grid space in the storage system such that a loading / unloading device occupying one grid space does not interfere with a loading / unloading device occupying or traversing an adjacent grid space in the X and / or Y directions.

[0009] Next, we will explain the communication system in detail, using an example. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 schematically illustrates the storage structure and containers. [Figure 2] Figure 2 schematically illustrates the track located above the storage structure shown in Figure 1. [Figure 3] Figure 3 schematically illustrates a cargo handling device located above the storage structure shown in Figure 1. [Figure 4] Figure 4 schematically illustrates a single cargo handling device in which the container lifting unit is in a downward configuration. [Figure 5] Figure 5 schematically illustrates a cutaway diagram of a single cargo handling device in which the container lifting unit is configured for both upward and downward movement. [Figure 6] Figure 6 shows a schematic diagram of the communication system according to this disclosure. [Figure 7] Figure 7 shows a schematic diagram of a bot for use with the communication system of this disclosure. [Figure 8] Figure 8 shows a schematic diagram of the grid covered by the first and second coverage areas. [Figure 9] Figure 9 shows a schematic diagram of the bot after it has moved on the grid. [Figure 10] Figure 10 shows a schematic diagram of the bot after a decision has been made to transfer the wireless connection to the second wireless access point. [Figure 11] Figure 11 shows a schematic diagram of the bot after the data has been routed through the second wireless access point. [Figure 12] Figure 12 shows a schematic diagram of the bot, where the coupled wireless interface is reconfigured to connect to a second wireless access point. [Figure 13] Figure 13 shows a schematic diagram of the combined wireless interface being further reconfigured. [Figure 14] Figure 14 shows a schematic diagram of an optional additional step in which the coupled wireless interface is further reconfigured. [Figure 15] Figure 15 shows a flowchart that provides a schematic explanation of the method according to this disclosure. [Modes for carrying out the invention]

[0011] The following examples represent the applicant's preferred examples of how communication systems for use with robots in warehouses may be implemented, but they are not necessarily the only examples of how it may be achieved.

[0012] Figure 1 illustrates a storage structure 1 comprising an upright member 3 and horizontal members 5 and 7 supported by the upright member 3. The horizontal members 5 extend toward each other and parallel to the illustrated x-axis. The horizontal members 7 extend toward each other and parallel to the illustrated y-axis and transversely to the horizontal members 5. The upright members 3 extend toward each other and parallel to the illustrated z-axis and transversely to the horizontal members 5 and 7. The horizontal members 5 and 7 form a grid pattern defining a plurality of grid cells. In the illustrated example, the containers 9 are arranged in a stack 11 below the grid cells defined by the grid pattern, with one container 9 per grid cell in the stack 11.

[0013] Figure 2 shows an enlarged plan view of a section of a track structure 13 that forms part of the storage structure 1 illustrated in Figure 1 and is located on top of the horizontal members 5, 7 of the storage structure 1 illustrated in Figure 1. The track structure 13 may be provided by the horizontal members 5, 7 themselves (for example, formed within or on the surface of the horizontal members 5, 7) or by one or more additional components attached to the top of the horizontal members 5, 7. The illustrated track structure 13 comprises x-direction track 17 and y-direction track 19, i.e., a first set of track 17 extending in the x direction and a second set of track 19 extending in the y direction, transverse to the track 17 in the first set of track 17. The track 17, 19 define an opening 15 in the center of the grid cell. The opening 15 is sized to allow containers 9 located below the grid cell to be lifted and lowered through the opening 15. The x-direction tracks 17 are provided in pairs separated by channels 21, and the y-direction tracks 19 are provided in pairs separated by channels 23. Other arrangements of the track structure may also be possible.

[0014] Figure 3 shows a plurality of load handling devices 31 moving along the top of the storage structure 1 illustrated in Figure 1. A load handling device 31, which may also be called a robot 31 or bot 31, is provided with a set of wheels to engage with a corresponding x-direction track 17 or y-direction track 19, enabling the bot 31 to travel across the track structure 13 and reach a particular grid cell. The illustrated pairs of tracks 17, 19, separated by channels 21, 23, allow the bot 31 to occupy (or pass over) adjacent grid cells without colliding with each other.

[0015] As illustrated in detail in FIG. 4, the bot 31 includes a body 33 in or to which one or more components are attached that enable the bot 31 to perform its intended functions. These functions can include moving over the storage structure 1 on the track structure 13 and raising or lowering the container 9 (e.g., from or to the stack 11), whereby the bot 31 can retrieve or place the container 9 at a specific location defined by the grid pattern.

[0016] The illustrated bot 31 includes a first set of wheels 35 and a second set of wheels 37, which are attached on the body 33 of the bot 31 and enable the bot 31 to move in the x and y directions respectively along the tracks 17 and 19. In particular, two wheels 35 are provided on the shorter side surface of the bot 31 visible in FIG. 4, and a further two wheels 35 are provided on the opposite shorter side surface of the bot 31 (the side surface and the further two wheels 35 are not visible in FIG. 4). The wheels 35 engage the track 17 and are rotatably attached on the body 33 of the bot 31 to enable the bot 31 to move along the track 17. Similarly, two wheels 37 are provided on the longer side surface of the bot 31 visible in FIG. 4, and a further two wheels 37 are provided on the opposite longer side surface of the bot 31 (the side surface and the further two wheels 37 are not visible in FIG. 4). The wheels 37 engage the track 19 and are rotatably attached on the body 33 of the bot 31 to enable the bot 31 to move along the track 19.

[0017] Bot 31 also includes a container lifting unit 39 configured to raise and lower the container 9. The illustrated container lifting unit 39 comprises four tapes or reels 41, which are connected at their lower ends to a container engagement assembly 43. The container engagement assembly 43 comprises an engagement mechanism configured to engage with the features of the container 9 (this may be provided, for example, at the corners of the assembly 43 near the tapes 41). For example, these containers 9 may be provided with one or more openings on their upper sides into which the engagement mechanism can engage. Alternatively or additionally, the engagement mechanism may be configured to hook under the rim or lip of the container 9 and / or to grip or grasp the container 9. The tapes 41 may be wound up or unwound as needed to raise or lower the container engagement assembly. One or more motors or other means may be provided to carry out or control the winding or unwinding of the tapes 41.

[0018] As shown in FIG. 5, the illustrated body 33 of the bot 31 has an upper portion 45 and a lower portion 47. The upper portion 45 is configured to house one or more operating components (not shown). The lower portion 47 is disposed directly below the upper portion 45. The lower portion 47 includes a container receiving space or cavity for receiving at least a portion of the container 9 lifted by the container lifting unit 39. The container receiving space is sized such that the container 9 can fit fully inside the cavity to allow the bot 31 to move across the track structure 13 at the top of the storage structure 1 without the lower side of the container 9 catching on the track structure 13 or another part of the storage structure 1. When the bot 31 reaches its intended destination, the container lifting unit 39 controls the tape 41 to lower the container gripping assembly 43 and the corresponding container 9 out of the cavity in the lower portion 47 and down to the intended position. This intended position can be the stack 11 of containers 9 or the exit point of the storage structure 1 (or, if the bot 31 has moved to collect a container 9 for storage within the storage structure 1, the entry point of the storage structure 1). In the illustrated example, the upper portion 45 and the lower portion 47 are separated by a physical partition, but the upper portion 45 and the lower portion 47 may not be physically divided by a particular component or part of the body 33 of the bot 31.

[0019] <000009- 6>To enable the bot 31 to move on different wheels 35, 37 in the first and second directions, the bot 31 includes a wheel positioning mechanism for selectively engaging either the first set of wheels 35 with the first set of tracks 17 or the second set of wheels 37 with the second set of tracks 19. The wheel positioning mechanism is configured to raise and lower the first set of wheels 35 and / or the second set of wheels 37 relative to the body 33, thereby enabling the load handling device 31 to selectively move in either the first or second direction across the tracks 17, 19 of the storage structure 1.

[0020] The wheel positioning mechanism may include one or more linear actuators, rotating components, or other means for raising and lowering at least one set of wheels 35, 37 relative to the body 33 of the bot 31 in order to bring at least one set of wheels 35, 37 into non-contact and contact states with the tracks 17, 19. In some examples, only one set of wheels is configured to be raised and lowered, and the action of lowering one set of wheels may effectively lift the other set of wheels away from the corresponding tracks, while the action of raising one set of wheels may effectively lower the other set of wheels into contact with the corresponding tracks. In other examples, both sets of wheels may be raised and lowered, which is advantageous as the body 33 of the bot 31 remains at substantially the same height, and therefore the weight of the body 33 and any components mounted thereon does not need to be raised and lowered by the wheel positioning mechanism.

[0021] To retrieve container 9 from the top of stack 11, the bot 31 is moved in the X and Y directions as necessary so that the container gripping assembly 43 is positioned above stack 11. The container gripping assembly 43 is then lowered vertically in the Z direction to engage with container 9 at the top of stack 11. The container gripping assembly 43 grips container 9 and is then pulled upward on the tape 41 with container 9 attached. At the top of its vertical movement, container 9 is housed within the vehicle body and held above track level. In this way, the cargo handling device 30 can be moved to different positions in the XY plane, transporting container 9 with it and transporting container 9 to another location. The tape 41 is long enough to allow the cargo handling device 30 to retrieve and place containers from any level of stack 11, including floor level. The weight of the vehicle may be provided in part of the battery used to power the drive mechanism for wheels 35, 37.

[0022] As shown in Figure 3, multiple cargo handling devices 31 are provided, so that each bot 31 can operate simultaneously to increase the system throughput. The system illustrated in Figure 3 may include specific locations known as ports, at which containers 9 can be transported to or from the system. Additional conveyor systems (not shown) are associated with each port, so that containers 9 transported to a port by a bot 31 can be transported by the conveyor system to another location, for example, a picking station (not shown). Similarly, containers 9 can be moved by the conveyor system from an external location to a port, for example, a container filling station (not shown), and then transported by a bot 31 to a stack 11 to replenish the stock in the system.

[0023] Each bot 31 can lift and move one container 9 at a time. If it is necessary to retrieve a container that is not located at the top of stack 11 ("target container"), the containers above it ("non-target containers") must first be moved to allow access to the target container. This is achieved in an operation hereafter referred to as "digging". During a digging operation, one of the bots 31 sequentially lifts each non-target container 9a from the stack 11 containing the target container 9b and places it in an empty position in another stack 11. The target container 9b can then be accessed by bot 31 and moved to a port for further transport.

[0024] Each of the bots 31 is under the control of the grid controller. Each individual container 9 in the system is tracked so that the appropriate container 9 can be retrieved, transported, and replaced as needed. For example, during a digging operation, the location of each non-target container is logged so that non-target containers can be tracked.

[0025] The system described with reference to Figures 1 to 5 has many advantages and is suitable for a wide range of storage and retrieval operations. In particular, it enables very high-density storage of products and provides a very economical way to store a wide range of different items in container 9 while allowing reasonably economical access to all of container 9 when needed for picking.

[0026] It should be understood that messages need to be sent to the bot. These may be short messages, such as instructions to move a container from a first location to a second location, or they may be larger messages, such as updates to the computer code used to operate the bot or its components. Similarly, the bot may need to send messages to a central management system to report, for example, operational parameter values, operational status reports, etc. Examples of communication systems that may be used are disclosed in the applicant's international patent application WO 2015 / 185726.

[0027] Figure 6 shows a schematic diagram of the communication system 100 according to this disclosure, where the fulfillment center comprises a grid 50 on which multiple bots 31 (not shown) move and operate, as described above with reference to Figures 1 to 5. The communication system 100 comprises two wireless access points 300A and 300B, each having associated coverage areas 310A and 310B (shown by dashed lines). Each of the wireless access points 300A and 300B is connected to a gateway 350, which is then communicably connected to a central computing system 400.

[0028] It should be understood that the shape of the coverage area is illustrative and not intended to represent the coverage area that will be achieved by the communication system according to this disclosure. It can be seen that the first coverage area 310A overlaps with the second coverage area 310B for part of the grid. It can also be seen that not the entire grid is covered by coverage areas 310A and 310B, but it will be understood that the communication system 100 has additional access points not shown in Figure 6 so that the entire grid surface is covered by at least one access point.

[0029] Notwithstanding the above description relating to Figures 4 and 5, Figure 7 shows a schematic diagram of a bot 31 for use with the communication system of the present disclosure. The bot 31 further comprises a first wireless antenna 32a, a second wireless antenna 32b, a first wireless network card 42A, a second wireless network card 42B, a security receiver 36, a real-time controller 38, and a bot PC 40. The first and second antennas 32a and 32b are located outside the bot body 33 and are configured to receive signals transmitted by the access point. The first wireless antenna 32a is connected to the first wireless network card 42A so that data received via the first wireless network card 42A is routed to the security receiver 36 and the bot PC 40. Similarly, the second wireless antenna 32b is connected to the second wireless network card 42B so that data received via the second wireless network card 42B is routed to the security receiver 36 and the bot PC 40.

[0030] In an alternative configuration, each of the first and second wireless network cards 42A and 42B may be connected to their respective antenna groups. For example, each of the first and second wireless network cards 42A and 42B may be connected to their respective antenna groups, each having two antennas, and as a result, each antenna in the antenna group may be used to form a spatial stream.

[0031] The signal received by the bot will consist of both a control signal and a safety signal. In one example, the control signal may be generated and transmitted separately from the safety signal. In an alternative example, the control signal and safety signal may be transmitted together as a composite signal. In such a case, additional components may be provided to separate the control signal and the safety signal (not shown in Figure 7).

[0032] The received control signals are processed by the bot PC 40. The bot PC 40 communicates with the first and second sets of wheels 35, 37 and can transmit signals to activate the first or second set of wheels as appropriate. The bot PC 40 also communicates with the container lifting unit 39 (see Figures 4 and 5) and can control the container lifting unit to, for example, lift a container from a stack in the grid structure to the bot, or lower a container from inside the bot to a stack in the grid. Thus, the bot PC can interpret and execute control signals so that the bot can operate efficiently as part of a group of bots operating on the surface of the grid.

[0033] The received safety signal is processed by the safety receiver 36. If safety conditions are detected by the safety receiver, the safety receiver may cause the real-time controller 38 to send a safety control signal to the bot PC 40. Receiving the safety control signal from the real-time controller invalidates the control signal received by the bot PC from the grid controller so that the bot's operation is stopped. If the bot is in the process of moving from a first grid location to a second grid location, the bot will stop at its current location. A stationary bot in the process of lifting or lowering a container may complete its action but will not take any further action until the safety control signal is invalidated.

[0034] Figure 8 shows a schematic diagram of bot 31 located within the coverage area 310A of the first wireless access point 300A. The bot establishes a wireless connection with gateway 350 via the first wireless access point 300A. For clarity, grid 50 and central computing system 400 are excluded from Figure 8. Similarly, while Figure 8 only shows the first and second wireless access points 300A and 300B and their respective coverage areas 310A and 310B, it should be understood that further wireless access points may exist.

[0035] During operation, the bot establishes a wireless connection 210 with wireless access point 300A because it is within coverage area 310A. The bot uses both the first wireless network card 42A and the second wireless network card 42B to create a coupled network connection to the first wireless access point. The coupled connection is formed to increase resilience. In the example shown in Figure 8, a coupled wireless interface 200 is established within the bot, and the first wireless network card 42A is the active secondary network interface, which is used to send data to and receive data from the first wireless access point. The second wireless network card 42B is the backup secondary network interface, which can be used to send and receive data in case of failure of the first wireless network card 42A. The active secondary network interface is indicated by a solid line from the first wireless network card 42A to the coupled wireless interface 200. The backup secondary network interface is indicated by a dotted line from the second wireless network card 42B to the coupled wireless interface 200. In the event of a failure of the first wireless network card 42A, the coupled wireless interface 200 can be reconfigured to route data through the second wireless network card, enabling data rerouting with minimal loss and thus minimizing the impact on the operational efficiency of the storage and retrieval system. In Figure 8, the data flow between the gateway 350 and the bot is symbolically represented using thick arrow lines.

[0036] Figure 9 shows a schematic diagram of the bot after it has moved across the grid as described above, with reference to Figure 8. The bot has moved to area 310AB, which is the area covered by both the first wireless access point 300A and the second wireless access point 300B. Since the bot is still within range of the first wireless access point 300A, the wireless connection 210 to the first wireless access point 300B is maintained in this case.

[0037] Since the bot is also within the coverage of the second wireless access point 300B, it may decide to forward the connection from the first wireless access point 300A to the second wireless access point 300B. The decision to forward the wireless connection may be based on one or more transmission parameters. For example, the RSSI (Received Signal Strength Indicator) value for the first wireless access point 300A may have fallen below a first predetermined threshold, and / or the RSSI (Received Signal Strength Indicator) value for the second wireless access point 300B may have exceeded a second predetermined threshold. Alternatively, or in addition, packet loss values ​​associated with the first and / or second wireless access points may be used when deciding whether to forward the wireless connection. Other parameters may be used in addition to or in place of these parameters, and it should be understood that the basis for the decision to forward the wireless connection is not important to this disclosure.

[0038] Figure 10 shows a schematic diagram of the bot described above with reference to Figures 8 and 9, after the decision has been made to transfer the wireless connection to the second wireless access point 300B. The second wireless network card 42B is used to establish a wireless connection 220 with the second wireless access point 300B. The wireless connection 210 to the first wireless access point is maintained, and data continues to flow between the gateway and the bot via the first wireless access point, as symbolically indicated by the thick arrow lines.

[0039] The next step in the process is shown in Figure 11. The gateway routes the data flow to the bot's second wireless network card 42B via the second wireless access point 300B and wireless connection 220. The data flow is symbolically represented by thick arrow lines. It can be seen that the network reconfiguration can be performed quickly and with minimal data loss, as it requires that the data be transmitted via the second wireless access point 300B rather than via the first wireless access point 300A. It can be seen that the wireless connection 210 between the first wireless network card 42A and the first wireless access point is still maintained at this point to facilitate efficient forwarding to the second wireless access point 300B.

[0040] Figure 12 shows the combined wireless interface being reconfigured to connect to the second wireless access point. This means that the first wireless network card 42A is then also connected to the second wireless access point via an additional wireless connection 230. It can be seen that the data flow to the bot continues to be routed through the second wireless network card 42B.

[0041] Figure 13 shows the coupled wireless interface 200 being further reconfigured so that a single coupled connection 240 is formed between the bot and the second wireless access point 300B. The second wireless network card 42B is the active secondary interface so that data is transmitted between the bot and the gateway via the second wireless network card 42B and the second wireless access point 300B. The first wireless network card 42A is the backup secondary interface so that data can be routed to the first wireless network card 42A in the event of failure of the second wireless network card 42B. Figure 14 shows a schematic diagram of an optional additional step, where the coupled wireless interface 200 is reconfigured so that the first wireless network card 42A becomes the active secondary interface (shown as a solid line in Figure 14) and the second wireless network card 42B becomes the backup secondary interface (shown as a dotted line). As before, the data flow between the gateway and the bot is symbolically represented by thick arrow lines.

[0042] Figure 15 shows a flowchart providing a schematic explanation of the method according to the present disclosure. In step S1500, the bot has an established coupled connection to a wireless access point (as described above with reference to Figure 8). In step S1510, the bot decides whether to switch the connection to a further access point. This decision may be made in response to the bot moving across the grid, a detected change in the network state, or a predetermined time period elapsed since the last iteration of S1510 was performed. If it is determined that there is no need to switch to a further access point, the bot waits and eventually performs S1510 again (for example, due to the bot moving across the grid, a detected change in the network state, an elapsed time period, etc.).

[0043] If it is determined that the bot should switch to an additional access point, in S1520 the bot will connect to the additional access point (see Figure 10 and the relevant explanation above). Once the connection is established, in S1530 the data flow to the bot will be rerouted to send (and receive) through the additional access point (see Figure 11 and the relevant explanation above). In S1540 the bot will disconnect from its original access point and, in S1550, connect to the additional access point via the coupled wireless interface (see Figure 12 and the relevant explanation above). Once the coupled connection is established with the additional access point, the method may be considered to terminate and the bot may return to step S1500.

[0044] Alternatively, the method may subsequently include an optional step S1560 (see Figure 14 and the relevant description above) to reconfigure the coupled connections to further access points before terminating. Again, the bot may be considered to have returned to step S1500.

[0045] Access points and wireless network interfaces may be selected to comply with one of the following wireless LAN standards, such as IEEE 8021.11n (sometimes called WiFi 4), 802.11 ac (WiFi 5), or 802.11 ax (WiFi 6). When further standards are agreed upon and compliant devices are released (e.g., 8021.11be [WiFi 7]), these may be adapted in this case. It will be understood that standards-compliant devices are selected to provide the desired level of network capacity and performance. From the above description, it will be understood that the native capabilities of the access points and wireless network interfaces are used to manage channels, etc., in the wireless LAN. It will be understood that this disclosure is implemented on software within a central computing system and / or bot PC. Such computer code may be provided on physical media such as DVDs, CD-ROMs, or USB memory sticks, or may be made available for download and installation.

[0046] According to one embodiment, a cargo handling device is provided that is designed to operate on top of a cube-shaped automated storage and retrieval system (ASRS). The cargo handling device comprises two wireless network interfaces that can be coupled to a single wireless connection with a wireless access point. When in use, one of the wireless network interfaces may be used to connect to a further wireless access point. Data can then flow from the ASRS to the cargo handling device via the further wireless access point. The coupled connection can then be reconfigured to connect via the further wireless access point.

Claims

1. A method for operating a cargo handling device in a storage and retrieval system, wherein the method is: a) The step of establishing a first wireless connection between the cargo handling device and the first wireless access point, i) The cargo handling device comprises a first wireless interface and a second wireless interface, ii) The first wireless connection is a coupling connection used to transfer data between the storage and retrieval system and the cargo handling device via the first wireless access point, iii) Both the first wireless interface and the second wireless interface are coupled to the first connection, the first wireless interface is the active interface, and the second wireless interface is the backup interface. b) When one or more conditions are met, a second wireless connection is established between the cargo handling device and the second wireless access point, and as a result, iv) The second wireless interface is removed from the coupled first wireless connection, v) The second wireless connection is established between the second wireless interface of the cargo handling device and the second wireless access point. A method that includes [a certain feature].

2. The method according to claim 1, wherein data is transferred between the storage system and the cargo handling device via the second wireless access point and the second wireless connection.

3. The method according to claim 2, wherein no data is transferred between the storage system and the cargo handling device via the first wireless access point.

4. The method according to claim 3, wherein the first wireless interface terminates the wireless connection with the first wireless access point and establishes a wireless connection with the second wireless access point.

5. The method according to claim 4, wherein both the first wireless interface and the second wireless interface are coupled to the second connection, the second wireless interface is the active interface, and the first wireless interface is the backup interface.

6. The method according to claim 5, wherein the second wireless connection is configured such that the first wireless interface is the active interface and the second wireless interface is the backup interface, and data is transferred between the storage system and the cargo handling device via the second wireless connection and the first wireless interface.

7. The method according to any one of claims 1 to 6, wherein in step b), the one or more conditions to be satisfied for establishing the second wireless connection relate to the received signal strength of the first wireless access point and / or the received signal strength of the second wireless access point.

8. The method according to claim 7, wherein in step b), the one or more conditions to be satisfied in order to establish the second wireless connection relate to the error rate in the first wireless connection.

9. A cargo handling device for use in a storage system, wherein the cargo handling device comprises a first network interface and a second network interface, and the cargo handling device is configured to perform the method according to any one of claims 1 to 8 when in use.

10. The cargo handling device according to claim 9, further comprising: a wheel assembly arranged to move selectively in one of two orthogonal directions; and a container lifting device arranged to lift a container from one of a plurality of stacks into the cargo handling device when in use.

11. A storage system comprising: a first set of parallel rails extending in the X direction in a substantially horizontal plane to form a grid pattern comprising multiple grid spaces; a second set of parallel rails extending in the Y direction traversing the first set; a plurality of stacks of containers located below the rails and arranged such that each stack is located within the installation area of ​​a single grid space; and at least one cargo handling device according to claim 9 or claim 10, wherein the at least one cargo handling device is arranged above the stacks on the rails to transport containers and is arranged to move selectively in the X and / or Y directions.

12. The storage system according to claim 11, wherein the at least one cargo handling device has an installation area that occupies only a single grid space in the storage system, such that a cargo handling device occupying one grid space does not interfere with a cargo handling device that occupies or crosses an adjacent grid space in the X and / or Y direction.

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