Optimal utilization of the operational capacity of dispatching container handling vehicles that interact with the same ports used to transfer storage containers to and from the automated storage and retrieval system

Abstract

A method, control system (500) and computer program for utilizing the operational capabilities of a container handling vehicle (201) when the container handling vehicle is tasked with delivering or retrieving an identified storage container (106) at the same port (119') of an automated storage and retrieval system (1), the automated storage and retrieval system comprising a frame structure (100) defining a storage grid (104) for storing storage containers (106) in storage columns (105) and where the storage containers (106) are handled by a container handling vehicle (201) operating atop the storage grid (104) and where ports (119') are used to transfer storage containers (106) to and from the storage and retrieval system (1). A control system (500) in communication with a vehicle controller (230) in each container handling vehicle (201) performs the following steps: assigning an indefinite task (310) to the container handling vehicle (201); calculating the end time and end position of the container handling vehicle (201) when the assigned task is completed (330); assigning a deadline task (320) to the container handling vehicle (201) to arrive at a port (119'); checking whether the container handling vehicle (201) can meet the deadline after first completing the indefinite task; sorting the tasks assigned to the container handling vehicle (201) (360), and further sorting the tasks that can meet the deadline after first completing the indefinite task first according to the time when the container handling vehicle (201) arrives at the port (119'); and executing the tasks (370) by transmitting instructions to the container handling vehicle (201) according to the sorting of the tasks.

Description

Technical Field

[0001] The present invention relates to an automated storage and retrieval system for storing and retrieving storage containers handled by container handling vehicles, and more particularly, to a method, system, and computer program for optimizing the operational capabilities of container handling vehicles that are designated to deliver or retrieve storage containers at the same port used to transfer storage containers to or from the automated storage and retrieval system. Background Art

[0002] FIG. 1 discloses a typical prior art automated storage and retrieval system 1 having a frame structure 100 and a container handling carrier 201 operating on the system 1 .

[0003] The frame structure 100 includes upright members 102, horizontal members 103, and a storage volume comprising storage columns 105 arranged in rows between the upright members 102 and the horizontal members 103. In these storage columns 105, storage containers 106 (also called bins) are stacked one on top of the other to form a stack 107. The members 102, 103 can typically be made of metal, such as extruded aluminum profiles.

[0004] The frame structure 100 of the automatic storage and retrieval system 1 includes a rail system 108 arranged on the top of the frame structure 100, and multiple container handling vehicles 201 operate on the rail system 108 to lift storage containers 106 from the storage column 105 and lower the storage containers 106 into the storage column 105, and also transport the storage containers 106 to above the storage column 105.

[0005] The track system 108 includes: a first set of parallel tracks 110, arranged to guide the container handling carrier 201 to move in a first direction X on the top of the frame structure 100; and a second set of parallel tracks 111, arranged perpendicular to the first set of tracks 110, to guide the container handling carrier 201 to move in a second direction Y perpendicular to the first direction X.

[0006] 1 also shows a first track 110a in a first direction X, a second track 110b in a first direction X, a first track 111a in a second direction Y, and a second track 111b in a second direction Y. The container handling carrier 201 moves laterally over the storage column 105, i.e., in a plane parallel to the horizontal XY plane.

[0007] Storage containers 106 are stored in columns 105, which define a third direction Z that is orthogonal to the first direction X and the second direction Y. Container handling vehicles 201 access storage containers 106 through access openings in a rail system 108, i.e., the rail system 108 is disposed on a frame structure 100 that defines the perimeter of each access opening 112 at the top of each storage column 105. Upright members 102 of frame structure 100 can be used to guide storage containers during lifting and lowering of containers from and into columns 105. Stacks 107 of containers 106 are generally self-supporting.

[0008] The storage volume of the frame structure 100 is generally referred to as a grid 104, wherein the possible storage locations within the storage columns 105 in the grid are referred to as storage cells. Each storage column 105 can be identified by its position in the X and Y directions, while each storage cell can be identified by a container number in the X, Y, and Z directions.

[0009] In the frame structure 100, most of the columns 105 are storage columns 105, ie columns 105 that are stored in stacks 107 by storage containers 106. However, some of the columns 105 may have other purposes.

[0010] In Figure 1, columns 119 and 120 are dedicated columns used by the container handling vehicle 201 to drop off and / or pick up the storage container 106 so that the storage container can be transferred to an access station (not shown) where the storage container 106 can be accessed from outside the frame structure 100 or transferred out of or into the frame structure 100.

[0011] In the prior art, the columns used to transfer storage containers into and out of a storage system are often referred to as port columns 119, 120 or transfer columns. Storage containers are transferred into and out of port columns 119, 120 via ports 119', 120'. Ports 119', 120' are typically located at the openings at one end of port columns 119, 120, i.e., the locations where storage containers enter or exit port columns 119, 120. Ports can also be located in other locations, such as in the middle of port columns 119, 120 or at ground level.

[0012] Storage containers 106 can be transported and transferred to the access station in any orientation, i.e., horizontal, inclined, and / or vertical. For example, storage containers 106 can be placed in random or dedicated columns 105 within the frame structure 100, then picked up by any container handling vehicle 201 and transported to the port columns 119, 120 for further transport to the access station. Note that the term "inclined" means that the storage container 106 is transported in an orientation generally between horizontal and vertical.

[0013] In Figure 1, the first port column 119 can be, for example, a dedicated unloading port column through which the container handling vehicle 201 can unload the storage container 106 to be transported to the access station or transfer station, and the second port column 120 can be a dedicated picking port column through which the container handling vehicle 201 can pick up the storage container 106 that has been transported out of the access station or transfer station.

[0014] The access station may typically be a pick-up station or a deposit station where product items are removed from or placed into the storage container 106. At the pick-up or deposit station, the storage container 106 is typically not removed from the automated storage and retrieval system 1, but rather, once accessed, is returned to the frame structure 100. The port posts 119, 120 may also be used to transfer the storage container to another storage facility (e.g., to another frame structure or another automated storage and retrieval system), to a transport vehicle (e.g., a train or truck), or to a production facility.

[0015] When a specific storage container 106 stored in one of the columns 105 disclosed in FIG1 is to be retrieved, one of the container handling vehicles 201 is dispatched and instructed to retrieve the storage container 106 from the location where the storage container 106 is located and transport it to the port 119′ of the port column 119. This operation includes moving the container handling vehicle 201 to a position above the storage column 105 where the 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 201, and transporting the storage container 106 to the port 119′ of the port column 119.

[0016] If the target storage container 106 is located deep within the stack 107, i.e., if there are one or more other storage containers 106 above the target storage container 106, the operation also includes temporarily moving the storage containers located above before lifting the target storage container 106 from the storage column 105. This step, sometimes referred to in the art as "digging," can be performed using the same container handling vehicle 201 that will subsequently transport the target storage container to the discharge port column 119, or using one or more other cooperating container handling vehicles 201. Alternatively or additionally, the automated storage and retrieval system 1 can include a container handling vehicle 201 specifically designed for the task of temporarily removing storage containers from the storage column 105. Once the target storage container 106 has been removed from the storage column 105, the temporarily removed storage container 106 can be replaced in the original storage column 105. Alternatively, however, the removed storage container 106 can be relocated to another storage column 105.

[0017] When a storage container 106 is to be stored in one of the columns 105, one of the container handling vehicles 201 is instructed to pick up the storage container 106 from the port 120' of the port column 120 used to transfer storage containers from the access station or transfer station and transport it to a position above the storage column 105 where it is to be stored. After removing any storage containers located at or above the target location within the storage column stack 107, the container handling vehicle 201 positions the storage container 106 at the desired location. The removed storage container 106 can then be lowered back into the storage column 105 or relocated to another storage column.

[0018] The position of each storage container 106 within the frame structure 100 and the position and movement of each container handling vehicle 201 operating on the storage and retrieval system are continuously monitored and controlled by the control system 500 and by reference to the contents of each storage container 106, so that the desired storage container 106 can be transported to the desired location at the desired time without the container handling vehicles 201 colliding with each other.

[0019] Figure 2 An example of a typical control system 500 is shown, which includes a main controller 220, a database 210 that tracks the trajectory of storage containers 106, a route planner 200 for finding the best route for the container handling vehicles 201, and a transmitter / receiver 225 for transmitting instructions to each container handling vehicle 201. The control system 500 communicates with the vehicle controller 230 in each container handling vehicle 201 and controls the traffic flow of the container handling vehicles 201 according to the route planner 200.

[0020] In the above description, separate port posts 119, 120 are described for transferring storage containers to and from the storage and retrieval system 1. This provides an effective solution. However, only one of the port posts 119, 120 can be used to transfer storage containers to and from the storage and retrieval system.

[0021] The automated storage and retrieval system 1 is typically operated by two or more container handling vehicles 201, each of which serves the same port 119' of a port column 119 and is used to transfer storage containers to a storage and retrieval station. Each container handling vehicle 201 is assigned a task based on instructions sent from the control system 500. For example, a task might involve retrieving a specific storage container 106 from the storage column 105 where the container handling vehicle 201 is located, traveling a specified distance in a specified direction, and delivering the storage container 106 to a port 119'.

[0022] According to the prior art, the emphasis is on delivering the storage container 106 to the port 119' as quickly as possible. When several container handling vehicles 201 serve the same port 119' to interact with it, the container handling vehicles 201 can be at the port 119' or traveling toward the port 119' at the same time by delivering or retrieving the storage container 106 to or from the port 119'. This can lead to problems of low efficiency at the port 119'. Before the container handling vehicle 201 can interact with the port 119', that is, before delivering the storage container 106 to or retrieving the storage container 106 from the port, the container handling vehicle 201 may have to wait in a queue. In this way, the operational capacity (operational capacity) of each container handling vehicle 201 is not optimally utilized.

[0023] In order to fully utilize the operational capabilities of the container handling vehicles 201 designated to service the same port 119', it is ideal that each container handling vehicle 201 arrives at the port 119' immediately after another container handling vehicle 201 has completed its interaction with the port, i.e., delivering or retrieving a storage container to or from the port 119'.

[0024] If the container handling vehicle 201 begins traveling toward port 119' too early, the operational capacity of the container handling vehicle 201 may not be optimally utilized because the container handling vehicle 201 may have to wait to deliver a storage container 106 to port 119' if other container handling vehicles 201 are simultaneously interacting with port 119' or moving toward port 119' to deliver or retrieve a storage container 106.

[0025] The present invention addresses and solves this problem by ensuring that a container handling carrier 201 services the port 119 ′ with minimal waiting time at the port 119 ′, thereby reducing the likelihood that the container handling carrier 201 will have to wait in line at the port 119 ′.

[0026] Instead of sitting still in a queue waiting for other container handling vehicles 201 to complete their interactions with the port, container handling vehicles 201 are directed to perform other intermediate tasks before delivering or retrieving storage containers 106 to or from the port. Summary of the Invention

[0027] According to the prior art, the emphasis is on delivering storage containers to ports as quickly as possible. However, this can cause delays for container handling vehicles serving the same port, as these container handling vehicles may be located at or traveling to the port at the same time. Consequently, some container handling vehicles may have to wait in line at the port before being able to interact with the port (i.e., deliver or retrieve storage containers to or from the port). This means that the operating capacity of each container handling vehicle is not optimally utilized.

[0028] According to the present invention, the operational capacity of each container handling carrier may be better utilized by preferentially having each container handling carrier designated to service the same port arrive at the port just before another container handling carrier has completed interaction with the port.

[0029] The present invention is defined by a method for utilizing the operational capabilities of a container handling vehicle when the container handling vehicle is tasked with delivering or retrieving an identified storage container at the same port of an automated storage and retrieval system, the automated storage and retrieval system comprising a frame structure defining a storage grid for storing storage containers in storage columns, and wherein the storage containers are handled by a container handling vehicle operating on top of the storage grid, and wherein the port is used to transfer the storage containers to and from the storage and retrieval system.

[0030] The location of the port is irrelevant to the solution according to the present invention. As mentioned above, the port can be located on a port column used to transfer storage containers at a consolidation station. The port can also be located at a consolidation station or a picking station. What is relevant to this solution is the time limit by which the container handling vehicle must arrive at the port.

[0031] The method includes the following steps performed by a control system in communication with a carrier controller in each container handling carrier:

[0032] - Assigning container handling vehicles with indefinite tasks and deadlines to reach the port;

[0033] - Calculate the end time and end position of the container disposal vehicle when the indefinite dispatch task is completed;

[0034] - Checks whether the container disposal vehicle can meet the deadline after first completing the indefinite-deadline task;

[0035] - sorting the tasks assigned to the container handling vehicles, and further prioritizing tasks that can meet deadlines after first completing tasks with no deadlines based on the time the container handling vehicles arrive at the port; and

[0036] - Execute tasks by sending instructions to container handling vehicles according to the order of tasks.

[0037] According to one embodiment, the end time and end location of the container handling vehicle upon completion of the assigned indefinite task are calculated based on parameters based on one or more of the following:

[0038] - the travel time from the container handling vehicle's current location to the task;

[0039] - other traffic conditions, including possible obstructions in the container handling vehicle's route from its location to the task;

[0040] - the time when container disposal vehicles are available;

[0041] - The container disposes of the vehicle's battery charge.

[0042] According to one embodiment, it is checked whether the container handling vehicle can meet the deadline based on the calculated end position and end time of the container handling vehicle after first completing the indefinite task.

[0043] According to one embodiment, container disposal carriers that can meet the deadline are awarded points, while container disposal carriers that cannot meet the deadline are awarded points, and are ranked according to the awarded points.

[0044] According to one embodiment of the method, if it is calculated that assigning an indefinite task will cause the container handling vehicle to miss the deadline of an assigned deadline task, the assigned deadline task is queued before the indefinite task, so that the deadline task is executed first and then the indefinite task.

[0045] According to one embodiment, an assigned but uncompleted indefinite task is reassigned to a different container handling vehicle that has the capability to complete the reassigned indefinite task within its schedule.

[0046] The present invention is further defined by a control system for utilizing the operational capabilities of a container handling vehicle when the container handling vehicle is tasked with delivering or retrieving an identified storage container at the same port of an automated storage and retrieval system, the automated storage and retrieval system comprising a frame structure defining a storage grid for storing storage containers in storage columns. The storage containers are handled by the container handling vehicle operating atop the storage grid, and wherein the ports are used to transfer storage containers to and from the storage and retrieval system. The system includes a control system in communication with a vehicle controller in each container handling vehicle. The control system includes a processor configured to execute a computer program that, when executed, performs the method described above.

[0047] The present invention is also defined by a computer program that, when executed by a processor in a control system of an automated storage and retrieval system, performs the above-described method for utilizing the operational capabilities of a container handling vehicle when the container handling vehicle is tasked with delivering or retrieving an identified storage container at the same port of the automated storage and retrieval system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings facilitate an understanding of the present invention. Embodiments of the present invention are illustrated in the accompanying drawings, which will now be described by way of example only. In the accompanying drawings:

[0049] FIG. 1 is a perspective view of a frame structure of a prior art automated storage and retrieval system.

[0050] Figure 2 A control system for controlling a container handling carrier operating on an automated storage and retrieval system is shown.

[0051] Figure 3 is a flow chart illustrating the different steps of a method of utilizing the operational capabilities of a container handling carrier.

[0052] Figure 4 is a table showing the tasks assigned to the container handling vehicles.

[0053] Figure 5 is a table showing the mission sequencing and dispatching of vehicles.

[0054] Reference Signs List

[0055] 1-Automatic storage and retrieval system

[0056] 100-frame structure

[0057] 102-Upright members of frame structure

[0058] 103-Horizontal members of frame structures

[0059] 104-Storage Grid Structure

[0060] 105-Storage Column

[0061] 106-Storage Container

[0062] 106'-Specific location of storage container

[0063] 107-Stack

[0064] 108-Track System

[0065] 110-parallel tracks in the first direction (X)

[0066] 110a - first track in the first direction (X)

[0067] 110b-second track in the first direction (X)

[0068] 111-parallel track in the second direction (Y)

[0069] 111a-first track in the second direction (Y)

[0070] 111b-second track in the second direction (Y)

[0071] 112-Access opening

[0072] 119-First port column

[0073] 119'-First Port

[0074] 120-Second port column

[0075] 120'-Second Port

[0076] 200-Route Planner

[0077] 201-Container Disposal Vehicle

[0078] 210-Database

[0079] 220-Main Controller

[0080] 225-Transmitter / Receiver

[0081] 230-Vehicle Controller

[0082] X-first direction

[0083] Y-second direction

[0084] Z-third direction

[0085] 500-Control System DETAILED DESCRIPTION

[0086] In the following description, the invention will be explained in more detail with reference to the accompanying drawings. It should be understood, however, that the drawings are not intended to limit the invention to the subject matter depicted in the drawings.

[0087] A typical prior art automated storage and retrieval system 1 having a frame structure 100 is described above with reference to FIG. 1 in the background section.

[0088] The frame structure 100 can be of any size, and it will be appreciated that the width and / or length and / or depth of the frame structure 100 can be much greater than that disclosed in Figure 1. For example, the frame structure 100 can have a horizontal extent of more than 700 x 700 columns and a storage depth of more than 12 containers.

[0089] Furthermore, the storage grid 104 may be much deeper than disclosed in Figure 1. For example, the storage grid 104 may be deeper than twelve grid cells 122, ie, in the Z direction as shown in Figure 1 .

[0090] The container handling carrier 201 may be of any type known in the art, such as any of the automated container handling carriers disclosed in WO 2014 / 090684 A1, NO 317366, or WO 2015 / 193278 A1.

[0091] A rail system 108 arranged at the top of the frame structure 100 allows the container handling carrier 201 to move horizontally between the storage column 105 and the first and second ports 119', 120' with which the container handling carrier 201 interacts, i.e., the ports 119', 120' to which the container handling carrier 201 delivers or from which it retrieves the storage container 106 as instructed.

[0092] When describing the present invention below, port 119' is used as an example of a port 119' with which a set number of container handling carriers 201 are designated to interact. The number of carriers may be, for example, 4 to 8.

[0093] The present invention provides a method and control system for avoiding queues at ports 119' by better controlling each container handling carrier 201 that is directed to interact with the same port 119'.

[0094] Figure 3 1 is a flow chart illustrating the various steps of a method for utilizing the operational capabilities of a container handling vehicle 201, wherein the container handling vehicle 201 is tasked with delivering or retrieving identified storage containers 106 at the same port of an automated storage and retrieval system 1 comprising a frame structure 100. The frame structure defines a storage grid 104 for storing storage containers 106 in storage columns 105. The storage containers 106 are handled by the container handling vehicle 201 operating atop the storage grid 104. In this example, a port 119' is located at the opening of the port column 119 for transferring storage containers 106 to and from the storage and retrieval system 1. A control system 500, in communication with the vehicle controller 230 in each container handling vehicle 201, performs several of the steps.

[0095] Each container handling vehicle 201 is assigned a task. For example, the assigned task may be to transport a specific storage container at the port 119' or to move a storage container from one location to another.

[0096] Some tasks have higher priority than others. High-priority tasks are assigned deadlines, while other tasks are undead. Deadline-bound tasks typically involve transferring a specific storage container to port 119.

[0097] The first step in the method 300 according to the present invention is to assign unexpired tasks 310 and limited tasks 320 to container handling vehicles 201. Which container handling vehicle 201 is assigned to handle a particular storage container 106 is based on cost parameters. Examples of cost parameters include the distance and travel time from the current location of the container handling vehicle 201 to the location of the particular storage container 106; excavation time; traffic conditions, including the possibility that other container handling vehicles 201 may block the path to the location of the storage container 106; the time the container handling vehicle 201 is available; the battery level of the container handling vehicle 201, etc.

[0098] The digging time is the time that the container handling vehicle 201 will use to remove other storage containers 106 located above the target storage container 106 in the storage column 105. The digging can be performed using the same container handling vehicle 201 used to transport the target storage container 106 to the port 119'. Alternatively, the digging can be performed by a dedicated container handling vehicle 201 used only for digging. In this case, the digging time can be ignored or at least reduced for the container handling vehicle 201 that is assigned the task (i.e., transporting a specific storage container 106 at the port 119').

[0099] Based on the cost parameters, the next step is to calculate the end time and end location 330 of the container handling vehicle 201 when the indefinite assignment task is completed.

[0100] As described above, this can be calculated based on cost parameters based on one or more of the following: the time elapsed when traveling from the current location of the container disposal vehicle 201 to a new location to complete the task; other traffic affecting the container disposal vehicle 201 when traveling from the current location of the container disposal vehicle 201 to the task; the time the container disposal vehicle 201 is available; and the battery charge of the container disposal vehicle 201.

[0101] The next step of the method is to check whether the container handling vehicle 201 can complete the limited-time assigned task after first completing the unlimited-time task. This check is performed by calculating the time it takes for the container handling vehicle 201 to start executing the limited-time task from its position after first completing the unlimited-time task.

[0102] In one embodiment, the inspection may result in points being awarded or deducted for the container disposal carrier 201. If the inspection concludes that the container disposal carrier 201 cannot meet the deadline 340, then points are deducted 345. If the inspection concludes that the container disposal carrier 201 can meet the deadline 340, then points are awarded 350.

[0103] In one embodiment, assigned but uncompleted indefinite tasks are reassigned to different container handling vehicles 201 that are capable of completing the reassigned indefinite tasks within their schedules. In this way, the container handling vehicles 201 can prioritize the definite tasks.

[0104] After that, the next step is to sort the tasks assigned to the container handling vehicle 201 based on the points added and deducted and the estimated time of arrival at the port 360. Tasks that can be performed within the deadline after the indefinite tasks are completed first are ranked first, and further based on the time when the container handling vehicle 201 arrives at the port 119'. Figure 4 and Figure 5 Describe an example.

[0105] The final step of the method is to execute the task by transmitting instructions according to the order of the task to the container handling vehicle 201. The instructions include information on where to pick up the storage container, which storage container 106 it is and to which port it will be delivered.

[0106] Figure 4 is a table showing examples of tasks assigned to a container handling vehicle 201. Indefinite tasks are represented as 1.1 to 6.1, while definite tasks are represented as 1.2 to 6.2. The table also shows whether the assigned container handling vehicle 201 can complete the indefinite assigned tasks and still perform the definite tasks. If so, the indefinite tasks are performed first, followed by the definite tasks. If not, the definite tasks are performed first, followed by the indefinite tasks. This is reflected in the task priority column in the figure, for example, for assigned vehicle 010, indefinite task 1.1 is performed before definite task 1.2. The last column shows an example of the time to arrive at the same designated port to which the storage container 106 will be transported, i.e., the time to arrive at port 119' before the deadline of the definite task for each designated container handling vehicle 201.

[0107] Figure 5 is a table showing the final order of tasks and the assigned vehicles when the tasks are executed as instructions to the container handling vehicle 201. The final order is based on Figure 4 The container handling carrier 201 that arrives at the port 119' first is ranked first, while the container handling carrier 201 that arrives at the port just before the deadline is ranked last.

[0108] According to the sorted list, the tasks assigned to the carriers are executed and instructions are sent to each container handling carrier 201. In this way, the operational capacity of each container handling carrier 201 is better utilized because unexpired tasks can be executed before deadline tasks while still allowing the container handling carrier 201 to complete the assigned tasks within the set deadline. Container handling carriers 201 designated to interact with the same port 119' are less likely to have to wait for each other to complete their interaction with the port, i.e., in terms of delivering or retrieving storage containers 106 to or from port 106'.

[0109] The present invention is further defined by a control system 500 for utilizing the operational capabilities of the container handling vehicle 201 when the container handling vehicle 201 is tasked with delivering or retrieving an identified storage container 106 at the same port 119', 120' of the automated storage and retrieval system 1, as described above with reference to FIG. 1 .

[0110] Refer to above Figure 2 A control system 500 is described, comprising a main controller 220, a database 210 that tracks the current location of the storage containers 106, a route planner 220 (also described above) for finding an optimal route for the container handling vehicles 201 based on cost parameters, and a transmitter / receiver 225 for transmitting instructions, preferably wirelessly, to each container handling vehicle 201. The control system 500 also includes a processor configured to run a computer program that, when executed, performs the method described above, thereby utilizing the operational capabilities of the container handling vehicles 201 when assigned both time-limited and time-indefinite tasks.

[0111] The present invention addresses and solves the problem of container handling vehicles having to wait in line at port 119'. Instead, port 119' is served by the container handling vehicle 201 that has the minimum waiting time at port 119' and, if possible, performs other intermediate tasks as directed before delivering or retrieving storage containers 106 to or from port 119' within the specified timeframe.

Claims

1. A method for operating a container handling vehicle (201), wherein: The container handling vehicles are arranged to perform the task of transporting or retrieving identified storage containers (106) at the same port (119') of an automated storage and retrieval system (1), wherein the automated storage and retrieval system includes a frame structure (100) defining a storage grid (104) for storing the storage containers (106) in storage columns (105), and wherein the storage containers (106) are handled by the container handling vehicles (201) running on top of the storage grid (104), and wherein the ports (119') are used to transfer the storage containers (106) to and from the automated storage and retrieval system (1), wherein the following steps are performed by a control system (500) in communication with a vehicle controller (230) in each container handling vehicle (201): - assigning an undetermined task and a time-limited task to the container handling vehicle (201) to reach the port (119'); - calculating the end time and end position of the container handling vehicle (201) when the assigned indefinite task is completed; - checking whether the container handling vehicle (201) can meet the deadline after first completing the unlimited task; - sorting the tasks assigned to the container handling vehicle (201), and further sorting the tasks that can meet the deadline after first completing the indefinite tasks according to the time when the container handling vehicle (201) arrives at the port (119'); - executing said tasks by transmitting instructions to said container handling vehicle (201) according to said ordering of tasks.

2. A method for operating a container handling vehicle (201) according to claim 1, wherein: The end time and end position of the container handling vehicle (201) upon completion of the assigned indefinite task are calculated based on one or more of the following parameters: - travel time from the current position of the container handling vehicle (201) to the indefinite task; - other traffic conditions, including possible obstructions on the route of the container handling vehicle (201) from its location to the indefinite task; - the time at which the container disposal vehicle (201) is available; - The container handles the battery charge of the vehicle (201).

3. A method for operating a container disposal vehicle (201) according to claim 1 or 2, wherein: Based on the calculated end position and end time of the container handling vehicle (201) after first completing the indefinite task, it is checked whether the container handling vehicle (201) can meet the deadline.

4. A method for operating a container handling vehicle (201) according to claim 3, wherein: The container disposal carrier (201) that can meet the deadline is given extra points, while the container disposal carrier (201) that cannot meet the deadline is deducted points, and is sorted according to the given points.

5. The method for operating a container handling vehicle (201) according to claim 3, wherein: If it is calculated that the dispatched indefinite task will cause the container handling vehicle to miss the deadline of the dispatched limited task, the dispatched limited task is queued before the dispatched indefinite task so that the limited task is executed first and then the indefinite task is executed.

6. A method for operating a container handling vehicle (201) according to claim 3, wherein: Reassigning assigned but uncompleted indefinite tasks to a different container handling vehicle that has the capability to complete the reassigned indefinite tasks within its schedule.

7. A control system (500) for operating a container handling vehicle (201), wherein: The container handling vehicle is arranged to perform the task of transporting or retrieving the identified storage container (106) at the same port (119') of an automated storage and retrieval system (1), the automated storage and retrieval system comprising a frame structure (100) defining a storage grid (104) for storing the storage containers (106) in storage columns (105), and wherein the storage containers (106) are handled by the container handling vehicle (201) running on top of the storage grid (104), and wherein the port (119') is used to transfer the storage containers (106) to the automated storage and retrieval system. Return system (1) and transfer of the storage containers from the automated storage and retrieval system, wherein the control system (500) includes a main controller (220), a database (210) for tracking the trajectory of the storage containers (106), a route planner (200) for finding an optimal route for the container handling vehicles (201), and a transmitter / receiver (225) for transmitting instructions to each container handling vehicle (201), wherein the control system (500) also includes a processor, the processor being arranged to run a computer program that, when executed, performs the method according to claims 1 to 6.

8. A computer program which, when executed by a processor in a control system (500) of an automated storage and retrieval system (1), performs the method for operating a container handling carrier (201) according to claims 1 to 6.

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