Method for handling malfunctioning vehicles on a rail system and a storage and retrieval system using such a method

Abstract

A method for handling malfunctioning vehicles (240,340) on a rail system (108,308) constituting part of a storage and retrieval system (1) configured to store a plurality of stacks (107) of storage containers (106), wherein the storage and retrieval system (1) comprisesa plurality of remotely operated vehicles (230,330,240,340,250,350) configured to move laterally on the rail system (108,308) anda control system (109) for monitoring and controlling wirelessly movements of the plurality of vehicles (230,330,240,340,250,350), the control system (109) forms by wireless data communication at least the following steps: A. registering an anomaly in an operational condition of a vehicle (this 240,340) on the rail system (108,308), B. registering the vehicle with the anomalous operational condition as a malfunctioning vehicle (240,340), C. bringing the malfunctioning vehicle (240,340) to a halt, D. registering a halt position of the malfunctioning vehicle (240,340) relative to the supporting rail system (108,308), E. setting up a two-dimensional shutdown zone (225) within the rail system (108,308) into which the malfunctioning vehicle (240,340) is halted and F. updating movement pattern of the plurality of remotely operated vehicles (230,330, 250,350) outside the two-dimensional shutdown zone (225) such that entrance into the two-dimensional shutdown zone (225) is avoided.

Claims

1. A method for handling malfunctioning vehicles on a rail system constituting part of a storage and retrieval system configured to store a plurality of stacks of storage containers, wherein the rail system comprises a first set of parallel rails arranged in a horizontal plane P and extending in a first direction X and a second set of parallel rails arranged in the horizontal plane P and extending in a second direction Y which is orthogonal to the first direction X, the first and second sets of rails forming a grid pattern in the horizontal plane P comprising a plurality of adjacent grid cells, each comprising a grid opening defined by a pair of adjacent rails of the first set of rails and a pair of adjacent rails of the second set of rails, wherein the storage and retrieval system comprises a plurality of remotely operated vehicles each configured to move laterally on the rail system and to lift the storage containers stacked in the stacks through the grid openings in the rail system using a lifting device, and a control system for monitoring and controlling wirelessly movements of the plurality of vehicles, wherein the control system forms by wireless data communication at least the following steps: A. registering an anomaly in an operational condition of a vehicle on the rail system, B. registering the vehicle with the anomalous operational condition as a malfunctioning vehicle, C. bringing the malfunctioning vehicle to a halt, D. registering a halt position of the malfunctioning vehicle relative to the supporting rail system, E. setting up a two-dimensional shutdown zone within the rail system into which the malfunctioning vehicle is halted, F. updating movement pattern of the plurality of remotely operated vehicles outside the two-dimensional shutdown zone such that entrance into the two-dimensional shutdown zone is avoided and G. dynamically rerouting any operating vehicle that is outside the shutdown zone to avoid physical impact with a service vehicle during transport of the service vehicle to the shutdown zone, and/or to avoid physical impact with an operator walking to the shutdown zone.

2. The method in accordance with claim 1, wherein the method further comprises the step of rerouting at least one vehicle of the plurality of vehicles other than the malfunctioning vehicle to a position on the rail system located at a boundary of the two-dimensional shutdown zone and bringing the at least one vehicle to a halt.

3. The method in accordance with claim 1 or 2, wherein the method further comprises after step E or F, determining whether other vehicles are operating within the two-dimensional shutdown zone.

4. The method in accordance with claim 3, wherein the method further comprises rerouting said other operating vehicles to continue operation outside the two-dimensional shutdown zone if the one or more other operating vehicles (230,330) are operating within the two-dimensional shutdown zone.

5. The method in accordance with claim 3, wherein the method further comprises bringing said other operating vehicles to a halt within or at the shutdown zone if one or more other operating vehicles are operating within the two-dimensional shutdown zone.

6. The method in accordance with claim 1, wherein the method further comprises guiding a service vehicle to a position at or within the shutdown zone.

7. The method in accordance with claim 6, wherein the service vehicle is guided from an access port at a lateral boundary of the rail system.

8. The method in accordance with claim 6, wherein the service vehicle comprises a caterpillar track configured to drive on top of the rail system.

9. The method in accordance with claim 1, wherein the method further comprises the step of rerouting operating vehicles other than the malfunctioning vehicle to positions on the rail system located at a boundary of the two-dimensional shutdown zone to create a physical barrier of vehicles around the malfunctioning vehicle, and bringing the other operating vehicles to a halt.

10. The method in accordance with claim 9, wherein the method further comprises guiding a service vehicle to a position at or within the shutdown zone and wherein the physical barrier of vehicles comprises an opening with a width larger than the width of the service vehicle, thereby allowing the service vehicle to enter into the shutdown zone or to form part of the physical barrier of vehicles.

11. The method in accordance with claim 1, wherein the rail system comprises a first rail system, a second rail system and a vehicle blocking barrier arranged between the first and the second rail system, wherein the vehicle blocking barrier comprises a vehicle passage having a minimum lateral width allowing one of the plurality of vehicles to move into the vehicle passage.

12. The method in accordance with claim 11, wherein the method further comprises the step of rerouting at least one of the plurality of vehicles other than the malfunctioning vehicle to a position within the vehicle passage and bringing the at least one vehicle to a halt.

13. The method in accordance with claim 1, wherein the storage and retrieval system comprises a transport rail system at height H.sub.T onto which a plurality of remotely operated container handling vehicles are configured to move laterally and a delivery rail system at height H.sub.D less than H.sub.T onto which a plurality of remotely operated container delivery vehicles are configured to move laterally and to receive storage containers from the higher located container handling vehicles, wherein the method steps B-G are performed for the plurality of container handling vehicles in a case where the control system registers an anomaly in an operational condition of a container handling vehicle or for the plurality of container delivery vehicles in a case where the control system registers an anomaly in an operational condition of a delivery handling vehicle or for the plurality of container handling vehicles and for the plurality of container delivery vehicles in a case where the control system registers an anomaly in an operation condition of both a transport handling vehicle and a container delivery vehicle.

14. The method in accordance with claim 13, wherein each of the plurality of container handling vehicles is configured to lift the storage containers stacked in the stacks through openings in the transport rail system using a lifting device, wherein the transport rail system comprises a first set of parallel rails arranged in a first direction and a second set of parallel rails arranged in a second direction orthogonal to the first direction, to move the storage containers to other locations on the transport rail system and to lower the storage containers down to the delivery rail system using the lifting device.

15. The method in accordance with claim 13, wherein each of the plurality of container delivery vehicles comprises a set of wheels configured to move the container delivery vehicle along rails of the delivery rail system and a drive motor configured to provide rotational power to the set of wheels, and a container carrier configured to receive the storage container from above and onto, or at least partly into, the container carrier, wherein the delivery rail system comprises a first set of parallel rails arranged in a first direction and a second set of parallel rails arranged in a second direction orthogonal to the first direction.

16. The method in accordance with claim 13, wherein the transport rail system comprises a plurality of laterally spaced apart transport rail system modules onto which the plurality of container handling vehicles are moving and wherein the delivery rail system is configured such that one of the plurality of container delivery vehicles is allowed to move below all or more than one of the plurality of laterally spaced apart transport rail system modules during normal operation.

17. The method in accordance with claim 13, wherein the method further comprises the step of rerouting the plurality of container delivery vehicles away from a two-dimensional zone projected down to the delivery rail system from any two-dimensional shutdown zones set up on the transport rail system.

18. An automated storage and retrieval system operating to handle malfunctioning vehicles by a method in accordance with any of claims 1-17.

19. A control system comprising a computer program that, when executed on a processor causes an automated storage and retrieval system to perform the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The following drawings are appended to facilitate the understanding of the invention:

(2) FIG. 1 is a perspective view of a prior art automated storage and retrieval system, where FIG. 1 A shows the complete system, FIG. 1 B shows a top view of a prior art double rail grid and FIG. 1 C shows an example of a system operable prior art container handling vehicle.

(3) FIG. 2 is a schematic top view of an automated storage and retrieval system according to a first embodiment of the invention, wherein the system is divided into three subsystems by physical barriers.

(4) FIG. 3 is a schematic top view of an automated storage and retrieval system according to a second embodiment of the invention, where FIG. 3A shows a situation where a shutdown zone has been created by a control system into which a malfunctioning container handling vehicle is parked, FIG. 3B shows a situation where a service vehicle is moving towards the shutdown zone while operative container handling vehicles have been instructed to create a physical barrier at the shutdown zone boundaries and FIG. 3C shows a situation where the service vehicle is entering the shutdown down.

(5) FIG. 4 is a schematic top view of the automated storage and retrieval system according to FIG. 3, where the service vehicle has fully entered the shutdown zone.

(6) FIGS. 5A and 5B are perspective views of an exemplary automated storage and retrieval system according to the invention, where FIG. 5A shows a part of the system having a delivery rail system with container delivery vehicles operating below the rail system of container handling vehicles and FIG. 5B shows an example of a container delivery vehicle having a storage container stored within.

(7) FIG. 6 is a schematic top view of an automated storage and retrieval system according to a third embodiment of the invention, where the system comprises a plurality of transport rail systems with container handling vehicles and one delivery rail system extending below all the transport rail systems.

(8) FIGS. 7A and 7B are perspective views of service vehicles suitable for operating on a rail system of an automated storage and retrieval system, where FIG. 7A shows a service vehicle having two set of wheels configured to follow the rails in X and Y directions and FIG. 7B shows a service vehicle having caterpillar tracks configured to drive on top of the rail system.

(9) FIG. 8 is a flow sheet describing an example of steps of a method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(10) In the following, embodiments of the invention will be discussed in more detail with reference to the appended drawings. It should be understood, however, that the drawings are not intended to limit the invention to the subject-matter depicted in the drawings.

(11) With reference to FIG. 1 the automated storage and retrieval system 1 comprises a framework structure 100 which includes a storage grid 104 of in total 1144 grid cells, where the width and length of the grid 104 corresponds to the width and length of 143 grid columns. The top layer of the framework structure 100 is a rail system 108 onto which a plurality of container handling vehicles 250 are operated.

(12) The framework structure 100 may be constructed in accordance with the prior art framework structure 100 described above, i.e. a plurality of upright members 102 and a plurality of horizontal members 103 which are supported by the upright members 102.

(13) The rail system 108 includes parallel rails 110,111 along the X direction and the Y direction, respectively, arranged across the top of storage columns 105. The horizontal area of a grid cell 122 delimiting the opening into the storage column 105 may be defined by the distance between adjacent rails 110 and 111, respectively.

(14) In FIG. 1, a single grid cell 122 is marked on the rail system 108 by thick lines in FIG. 1A and shown in a top view in FIG. 1B.

(15) The rail system 108 allows the container handling vehicles 250 to move horizontally between different grid locations, where each grid location is associated with a grid cell 122.

(16) In FIG. 1A the storage grid 104 is shown with a height of eight cells. It is understood, however, that the storage grid 104 can in principle be of any size. In particular, It is understood that storage grid 104 can be considerably wider and/or longer than disclosed in FIG. 1. For example, the grid 104 may have a horizontal extension of more than 700700 grid cells 122. Also, the grid 104 can be considerably deeper than disclosed in FIGS. 1 and 2. For example, the storage grid 104 may have a depth corresponding to a stable 107 of ten storage containers 106 or more.

(17) All container handling vehicles 250 may be controlled by a remote control system 109.

(18) The container handling vehicles 250 may be of any type known in the art, e.g. any one of the automated container handling vehicles disclosed in WO2014/090684 A1, in NO317366 or in WO2015/193278A1.

(19) FIG. 2 shows a top view of an automated storage and retrieval system 1 according to a first embodiment of the invention. The system 1 comprises three framework structures 100a-c, each having a storage grid 104 with stacks 107 of storage containers 106, a rail system 108a-c arranged on top of the storage grid 104 and an access port 160a-c. The framework structures 100a-c are separated by two vehicle blocking barriers 125, e.g., walls, arranged between the rail systems 108a-c. Each of the barriers 125 includes one or more passages 130a,b in which container handling vehicles 250 may drive through during normal operation.

(20) In FIG. 2 a particular situation is depicted where a container handling vehicle 240 has been labeled malfunctional and brought to a halt at a location on the mid rail system 108b. As a response to the presence of the malfunctioning vehicle 240, some of the container handling vehicles 230 are instructed by a control system 109 to move into the passages 130a,b of both barriers 125 to create two continuous (e.g., at least having no gaps which a vehicle can pass through) physical barriers along the entire length of the rail system 108a-c, thereby preventing operative container handling vehicles 250 located on the left and right rail systems 108a,108c to enter the mid rail system 108b. Any remaining container handling vehicles 230 still in operation on the mid rail system 108b are brought to a halt. Consequently, there will be no container handling vehicles 250 operative within the mid rail system 108b. Such a zone will hereinafter be called a shutdown zone 225.

(21) All of the above-mentioned steps are controlled and monitored by a remote control system 109.

(22) With no operative vehicles 250 within the shutdown zone 225, an operator may enter the rail system 108b via a mid access port 160b. The operator may choose to walk to, for example, the malfunctioning vehicle 240 on foot.

(23) However, in a preferred example of the method, a service vehicle 20 enters the mid rail system 108b via the mid access port 160b and drives across the mid rail system 108b to, for example, the malfunctioning container handling vehicle 240, preferably with an onboard operator.

(24) To minimize the risk of injury or accidents, the above step of entering the rail system 108 with a service vehicle 20 through an access port 160 is preferably performed after the above described process of creating the shutdown zone 225. But the step may also be performed, or initiated, during the process if this is considered sufficiently safe.

(25) The access ports 160a-c may be adjacent to a mezzanine outside the boundary of the rail systems 108, for supporting the service vehicle 20 while it is inactive.

(26) In FIG. 2, an access port 160a-c and a service vehicle 20 is depicted for each of the rail systems 108a-c. However, other configurations may be envisaged such as an arrangement of only one mid access port 160b, allowing entrance of a service vehicle 20 into the mid rail system 108b. In case a malfunctioning vehicle 240 is brought to a halt in the left rail system 108a or the right rail system 108c, the service vehicle 20 may, with such a configuration, travel through the respective passage 130a,b and into the affected rail system 108a,c. To reduce the risk of a collision of an operative container handling vehicle 250 with the service vehicle 20 during its movement across the mid rail system 108b, these container handling vehicles 250 in this zone may be temporary halted and/or temporary rerouted away from the service vehicle 20.

(27) FIG. 3 shows a second embodiment where the automated storage and retrieval system 1 includes a single framework structure 100 having a rail system 108 and an underlying storage grid 104 with stacks 107 of storage containers 106.

(28) Three different stages of the inventive method as illustrated in FIG. 3A-C:

(29) FIG. 3A shows the situation where the control system 109 has detected a malfunctioning container handling vehicle 240, brought the malfunctioning vehicle 240 to a halt and generated a shutdown zone 225 of size 65 grid cells into which the halted malfunctioning vehicle 240 is located.

(30) FIG. 3B shows a later situation where the control system 109 has instructed a service vehicle 20 to drive from an access port 160 to the shutdown zone 225 and instructed sixteen 230 of the operative container handling vehicles 250 to move towards the boundaries of the generated shutdown zone 225 to create a physical barrier partly surrounding the malfunctioning vehicle 240 and rerouting all other operative container handling vehicles 250 to prevent (or at least significantly reduce the risk of) collisions between an operative container handling vehicle 250 and the service vehicle 20 when the service vehicle 20 is travelling between the access port 160 and the shutdown zone. The general direction of the service vehicle 20 is indicated by a double line arrow 21.

(31) FIG. 3C shows yet a later situation where the service vehicle 20 has partly entered an opening in the physical barrier of vehicles 230.

(32) Whilst the operator is on the service vehicle 20, he or she may be relatively safe, protected by safety barriers fitted around a cockpit area of the service vehicle. Once the service vehicle 20 has entered the shutdown zone 225, the operator may want to step off the service vehicle 20 to service the malfunctioning vehicle 240. Thus, at this point any operator previously on the service vehicle 20 may at this latter stage perform work on the malfunctioning vehicle 240 while out of the protection of the service vehicle 20. The work may involve any in-situ maintenance work and/or transport of the vehicle 240 on the service vehicle 20 to another location, for example a workshop outside the rail system 108.

(33) A similar scenario as in FIG. 3C is shown in FIG. 4, but where the service vehicle 20 has fully entered a 66 grid cell large shutdown zone 20 bounded by 22 parked container handling vehicles 230. In addition to the malfunctioning vehicle 240, a functioning vehicle 230 has been brought to a halt within the shutdown zone 225 to ensure safe working conditions.

(34) As shown, a central point of the shutdown zone 225 may be offset with respect to the malfunctioning vehicle 240. This creates an area to receive the service vehicle 20 and/or an operator within the shutdown zone 225 whilst minimizing the number of other vehicles 230 required to form the physical barrier.

(35) The barrier in FIG. 4 is set up in the same way as in FIG. 3C, but without vehicles 230 in each corner.

(36) In general, the shutdown zone 225 and the corresponding boundary defining, parked vehicles 230 may be of any shape when viewed from above, for example circular, oval, triangular, hexagonal, octagonal, etc.

(37) If the malfunctioning vehicle 240 has been brought to a halt near an obstacle such as a roof pillar or near a periphery of the rail system 108, a part trigonometric form such as a half-octagonal shape or half-rectangular shape may be advantageous as a barrier.

(38) Further, the boundary setting vehicles 230 may be placed on different positions relative to the boundaries of the shutdown zone 225. In FIGS. 3C and 4 each vehicle 230 is placed outside the boundaries with one of its walls (an outermost vehicle wall from the malfunctioning vehicle 240) at a horizontal/lateral position equal to the corresponding position of the boundaries. However, an alternative position may be envisaged such that each or some of the vehicles 230 are placed at least partly on the boundaries or fully within the shutdown zone 225 with one outer wall at a horizontal/lateral position equal to the corresponding position of the boundaries.

(39) In order to provide a barrier that better may withstand collisions from outside, a barrier of vehicles 230 may also be more than one vehicle wide. Such vehicles 230 may be staggered. In some cases it may be desirable to space some of the vehicles 230 from an adjacent vehicle, but only by an amount which is less than a width of the vehicles 230.

(40) If the service vehicle 20 enters fully into the shutdown zone 225, the safety for the operator may be further improved by instructing (via the control system 109) additional operative container handling vehicles 250 to close the opening into the shutdown zone 225.

(41) A different automated storage and retrieval system 1 is shown in part in FIG. 5A. The upright members 102 constitute part of a framework structure 100 onto which a transport rail system 108 with a plurality of container handling vehicles 250 are operating.

(42) Below this transport rail system 108, near the floor level, another framework structure 300 is shown which partly extends below some of the storage columns 105 of the framework structure 100. As for the other framework structure 100, a plurality of vehicles 330,340,350 may operate on a rail system 308 comprising a first set of parallel rails 310 directed in a first direction X and a second set of parallel rails 311 directed in a second direction Y perpendicular to the first direction X, thereby forming a grid pattern in the horizontal plane P.sub.L comprising a plurality of rectangular and uniform grid locations or grid cells 322. Each grid cell of this lower rail system 308 comprises a grid opening 315 being delimited by a pair of neighboring rails 310a,310b of the first set of rails 310 and a pair of neighboring rails 311a,311b of the second set of rails 311.

(43) The part of the lower rail system 308 that extends below the storage columns 105 are aligned such that its grid cells 322 are in the horizontal plane P.sub.L coincident with the grid cells 122 of the upper rail system 108 in the horizontal plane P.

(44) Hence, with this particular alignment of the two rail systems 108,308, a storage container 106 being lowered down into a storage column 105 by a container handling vehicle 250 can be received by a delivery vehicle 350 configured to run on the rail system 308 and to receive storage containers 106 down from the storage column 105.

(45) FIG. 5B shows an example of such a vehicle 350 comprising a wheel assembly 351 similar to the wheel assembly 251 described for the prior art container handling vehicle 250 and a storage container support 352 for receiving and supporting a storage container 106 delivered by an above container handling vehicle 250.

(46) After having received a storage container 106, the delivery vehicle 350 may drive to an access station adjacent to the rail system 308 (not shown) for delivery of the storage container 106 for further handling and shipping.

(47) Hereinafter, the upper and lower rail systems 108,308 are called the transport rail system 108 and the delivery rail system 308. Likewise, the vehicle shown in FIG. 5B is called a container delivery vehicle 350.

(48) FIG. 6 shows a third embodiment of an automated storage and retrieval system 1. The system 1 includes four spaced apart transport rail systems 108a-d, each with operative container handling vehicles 250, and a delivery rail system 308 designed as a four grid cells wide path extending below all four of the transport rail systems 108a-d in a closed loop. As a result, any operative container delivery vehicle 350 may receive storage containers 106 from a storage column 105 belonging to any of the transport rail systems 108a-d.

(49) At the outer periphery of the delivery rail system 308 several delivery ports 370 are arranged to receive (and possibly also deliver) storage containers 106 to the container delivery vehicles 350.

(50) The outer periphery also contains a number of access ports 360 distributed in the horizontal plane P.sub.L, where each access port 360 is configured to allow entrance of a service vehicle 20 into the delivery rail system 308.

(51) FIG. 6 shows a scenario where the control system 109 has detected a malfunctioning container delivery vehicle 340, instructed the malfunctioning vehicle 340 to halt, generated a shutdown zone 325 around the malfunctioning vehicle 340 which includes one of the access ports 360, instructed eight 330 of the operative container delivery vehicles 350 to halt at the boundaries of the shutdown zone 325 to create a physical barrier for all the operative container delivery vehicles 350 located outside the shutdown zone 325 and instructing all others container delivery vehicles 330 located within the shutdown zone 325 to halt.

(52) With the scenario depicted in FIG. 6, the service vehicle 20 may enter the access port 360 and drive to the malfunctioning container delivery vehicle 340 with little or no risk of collision with other container delivery vehicles 350 still operative on the delivery rail system 308.

(53) During the operation of one or more service vehicles 20 on the delivery rail system 308, other service vehicles 20 may be operating on the transport rail system(s) 108 by use of the corresponding access ports 160.

(54) Two possible configurations of a service vehicle 20 suitable for the operations described above are shown in FIG. 7A and FIG. 7B.

(55) Both examples of service vehicles 20 comprises a lifting mechanism 24, a seat 25 for the operator and a support base 22 for support of malfunctioning vehicles 240,340 and driving means 23 to enable movement of the service vehicle 20. The service vehicle 20 could of course comprise other configurations and the present invention is not limited to these two examples.

(56) In FIG. 7A the driving means 23 comprises two set of four wheels, where at least one of the sets may be raised and lowered. Hence, the driving means are similar to the driving means of the above described container handling vehicles 250 and container delivery vehicles 350. The wheels follow the rails 110,310,111,311 of the transport and/or delivery rail system(s) 108,308.

(57) In FIG. 7B the driving means 23 of the service vehicle 20 comprises caterpillar tracks configured to drive on top of the rails 110,310,111,311, thereby allowing movement in any direction in the horizontal planes P,P.sub.L of either the transport rail system 108 or the delivery rail system 308.

(58) The service vehicle of FIG. 7B may be used as an alternative to, or in conjunction with, the service vehicle 20 of FIG. 7A

(59) A flow chart 400 describing one example of the inventive method is shown in FIG. 9 where the following method steps are executed/controlled by the control system 109: 401. An anomaly in one or more operation conditions of a vehicle 250,350 intended operating on either the transport rail system 108 or the delivery rail system 308 is registered/detected. Examples of operation conditions are positional accuracy, acceleration pattern, temperature, charging efficiency of battery and contact with underlying rail system. 402. The vehicle having the anomaly is labelled as a malfunctioning vehicle 240,340. 403. The malfunctioning vehicle 240,340 is instructed to halt, either immediately or at a specific location on the rail system 108,308. 404. The stop position of the malfunctioning vehicle 240,340 is registered in the control system 109. 405. A shutdown zone 225,325 is generated/set on the rail system 108,308, in which the malfunctioning vehicle 240,340 has been brought to a halt. 406. Are there any operative vehicles 250,350 within the shutdown zone 225,335? 407. If yes, either a. park one or more of the operating vehicles within the shutdown zone or b. guide one or more of the operating vehicles out of the shutdown zone, alternatively to a boundary of the shutdown zone 225,335 (see step 408), or c. a combination thereof, such that the shutdown zone 225,335 may become void of any operative vehicles 250,350. 408. If not already completed in step 407b, one or more of the operating vehicles 230,330 are brought to a halt at positions on or at the lateral boundaries of the shutdown zone 225,325 in order to create a physical barrier which at least partly prevent other operating vehicles 250,350 to enter. 409. A service vehicle 20 is guided at or into the shutdown zone 225,325 in order to allow handling and/or maintenance of the malfunctioning vehicle 240,340. 410. The operating vehicle 250,350 outside the shutdown zone is rerouted in order to avoid collision with the service vehicle 20 during the travel of the service vehicle 20 between the access station 160 (or any other initial position) and the shutdown zone 225,325

(60) If the operator intends to walk on foot to the malfunctioning vehicle 240,340, i.e. to avoid using a service vehicle 20, a plurality of the operating container handling vehicles 250,350 may be used to create a walking passage between the access port 160,360 and the malfunctioning vehicle 240,340.

(61) For example, the plurality of vehicles 250,350 may be arranged to create two lines of halted vehicles 230,330 extending from the access port 160 and to the boundary of the shutdown zone 225,325 and any vehicle created physical barrier. The distance between the two lines of vehicles 230,330 should be at least one grid cell 122,322 wide, for example three grid cells 122,322 wide.

(62) Such a walking passage may also be a dynamic exclusion zone where the operative vehicles 250,350 are instructed to move at a certain distance from the operator while he or she is on the rail system 108,308.

(63) In the preceding description, various aspects of the method and its related system according to the invention have been described with reference to the illustrative embodiment. For purposes of explanation, specific numbers, systems and configurations were set forth in order to provide a thorough understanding of the system and its workings. However, this description is not intended to be construed in a limiting sense. Various modifications and variations of the illustrative embodiment, as well as other embodiments of the method and the system, which are apparent to persons skilled in the art to which the disclosed subject matter pertains, are deemed to lie within the scope of the present invention.

LIST OF REFERENCE NUMERALS/LETTERS

(64) 1 Automated storage and retrieval system 20 Service vehicle 21 Direction of service vehicle 22 Support base for malfunctioning vehicle 23 Driving means for the service vehicle 24 Lifting mechanism 25 Seat for operator 100 Framework structure 100a First framework structure 100b Second framework structure 100c Third framework structure 102 Upright members of framework structure 103 Horizontal members of framework structure 104 Storage grid/three-dimensional grid 105 Storage column 106 Storage container 107 Stack 108 Transport rail system 108a First transport rail system 108b Second transport rail system 108c Third transport rail system 108d Fourth transport rail system 109 Control system 110 First set of parallel rails in first direction (X) 111 Second set of parallel rails in second direction (Y) 115 Grid opening in transport rail system 119 Delivery column 120 Delivery column 122 Grid cell of transport rail system 125 Vehicle blocking barrier 130 Vehicle passage between transport rail systems 130a First passage 130b Second passage 160 Access port to transport rail system for service vehicle 160a First access station 160b Second access station 160c Third access station 225 Shutdown zone on transport rail system 230 Parked container handling vehicle 230 Boundary defining, parked vehicle 230 Non-boundary defining, parked vehicle 240 Malfunctioning container handling vehicle 250 Operative container handling vehicle 251 Wheel assembly for container handling vehicle 252 Vehicle body for container handling vehicle 300 Delivery framework structure 308 Delivery rail system 310 First set of parallel rails in first direction (X) on delivery rail system 311 Second set of parallel rails in second direction (Y) on delivery rail system 315 Grid opening in delivery rail system 322 Grid cell of delivery rail system 325 Shutdown zone on delivery rail system 330 Parked container delivery vehicle 330 Boundary defining, parked vehicle 330 Non-boundary defining, parked vehicle 340 Malfunctioning container delivery vehicle 350 Operative container delivery vehicle 351 Wheel assembly for container delivery vehicle 352 Storage container support 360 Access station to delivery rail system for service vehicle 360 Access station to shutdown zone of delivery rail system for service vehicle 370 Delivery port for delivering storage containers by container delivery vehicles 400 Flow chart for handling malfunctioning vehicles 401 Registering an anomaly in an operational condition of a vehicle 402 Labelling the vehicle as a malfunctioning vehicle 403 Requesting the malfunctioning vehicle to stop or remain still 404 Registering the stop position of the malfunctioning vehicle 405 Setting up a shutdown zone on the rail system into which the malfunctioning vehicle is in a stop position 406 Presence of operative vehicles within the shutdown zone? 407a Parking any operating vehicles within the shutdown zone 407b Guiding any operating vehicles out of the shutdown zone 408 Parking a plurality of operating vehicles at positions on or at the shutdown zone's lateral boundaries 409 Guiding a service vehicle into the shutdown zone for handling of the malfunctioning vehicle 410 Rerouting the operating vehicle in order to avoid collision with the service vehicle when located outside the shutdown zone X First direction Y Second direction Z Third direction P Horizontal plane of rail system