Method for monitoring a storage system using an aerial drone

Abstract

A method for monitoring an automated storage and retrieval system (1) utilizing an aerial drone (400) to locate and inspect for anomalies in the system's operation. In one embodiment, the method comprises the steps of: a. launching an aerial drone (400) equipped with a camera (415) to an altitude within an airspace (408) located between an upper surface (410) of the framework structure (100) and a ceiling (412) or a roof obstruction (414) directly below the ceiling; b. navigating the drone (400) to a suspected location of an anomaly in the system or other aspect of the system requiring inspection; c. using the drone to locate the anomaly or aspect of the system requiring inspection; and d. using the aerial drone's camera to conduct a visual inspection of the anomaly or aspect of the system requiring inspection.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates to automated storage and retrieval systems for the storage and retrieval of containers, and in particular to methods for monitoring such systems for errors, and more particularly to methods for locating and monitoring disabled or malfunctioning autonomous container handling vehicles operating on such systems. [Background technology]

[0002] Background and Prior Art FIG. 1 discloses a typical prior art automated storage and retrieval system 1 with a framework structure 100, and FIGS. 2 and 3 disclose two different prior art container handling vehicles 201, 301 suitable for operating on such a system 1.

[0003] The skeletal structure 100 comprises upright members 102, horizontal members 103, and a storage volume comprising storage columns 105 arranged side by side between the upright members 102 and the horizontal members 103. In these storage columns 105, storage containers 106, also known as receptacles, are stacked on top of each other to form stacks 107. The members 102, 103 may typically be made from metal, for example, extruded aluminum profiles.

[0004] The framework structure 100 of the automated storage and retrieval system 1 comprises a rail system 108 arranged across the top of the framework structure 100, on which a plurality of container handling vehicles 201, 301 are operated to lift storage containers 106 from, lower storage containers 106 into, and transport storage containers 106 up the storage columns 105. The rail system 108 comprises a first set 110 of parallel rails arranged to guide movement of the container handling vehicles 201, 301 in a first direction X across the top of the framework structure 100, and a second set 111 of parallel rails arranged perpendicular to the first set of rails 110 to guide movement of the container handling vehicles 201, 301 in a second direction Y that is perpendicular to the first direction X. The containers 106 stored in the columns 105 are accessed by container handling vehicles through access openings / grid cells 112 in the rail system 108. The container handling vehicles 201, 301 can move laterally above the storage columns 105, i.e., in a plane parallel to the horizontal XY plane.

[0005] The uprights 102 of the skeletal structure 100 may be used to guide the storage containers during lifting of the containers out of the column 105 and during lowering of the containers into the column 105. The stacks 107 of containers 106 are typically freestanding.

[0006] Each prior art container handling vehicle 201, 301 comprises a carbody 201a, 301a, respectively, and first and second sets of wheels 201b, 301b, 201c, 301c that allow lateral movement of the container handling vehicle 201, 301 in the X and Y directions. Two wheels in each set are fully visible in Figures 2 and 3. The first set of wheels 201b, 301b are arranged to engage two adjacent rails of the first set of rails 110, and the second set of wheels 201c, 301c are arranged to engage two adjacent rails of the second set of rails 111. At least one of the sets of wheels 201b, 301b, 201c, 301c can be raised and lowered so that the first set of wheels 201b, 301b and / or the second set of wheels 201c, 301c can be engaged with a respective set of rails 110, 111 at any one time.

[0007] Each prior art container handling vehicle 201, 301 also includes a lifting device (not shown) for vertical transportation of the storage containers 106, e.g., lifting the storage containers 106 from the storage columns 105 and lowering the storage containers 106 into the storage columns 105. The lifting device includes one or more gripping / engaging devices adapted to engage the storage containers 106, and the gripping / engaging devices can be lowered from the vehicle 201, 301 such that the position of the gripping / engaging devices relative to the vehicle 201, 301 can be adjusted in a third direction Z that is orthogonal to the first direction X and the second direction Y. A portion of the gripping device of the container handling vehicle 301, designated by reference numeral 304, is shown in FIG. 3. The gripping device of the container handling device 201 is located within the vehicle body 301a of FIG. 2.

[0008] As before, and for purposes of this application, Z=1 identifies the top layer of storage containers, i.e., the layer immediately below rail system 108, Z=2 identifies the second layer below rail system 108, Z=3 identifies the third layer, and so on. In the exemplary prior art disclosed in FIG. 1, Z=8 identifies the lowest bottom layer of storage containers. Similarly, X=1...n and Y=1...n identify the position of each storage column 105 in the horizontal plane. Thus, using, by way of example, the Cartesian coordinate system X, Y, Z shown in FIG. 1, the storage container identified as 106' in FIG. 1 can be said to occupy storage location X=10, Y=2, Z=3. A container handling vehicle 201, 301 can be said to travel in layer Z=0, and each storage column 105 can be identified by its X and Y coordinates.

[0009] The storage volume of the skeleton structure 100 is often referred to as a grid 104, and the possible storage locations within this grid are referred to as storage cells. Each storage column may be identified by a position in the X and Y directions, while each storage cell may be identified by a container number in the X, Y, and Z directions.

[0010] Each prior art container handling vehicle 201, 301 includes a storage compartment or space for receiving and stowage of the storage containers 106 as they are transported across the rail system 108. The storage space may include a centrally arranged cavity within the vehicle body 201 a, as shown in FIG. 2 and as described, for example, in WO 2015 / 193278 A1 (Patent Document 1), the contents of which are incorporated herein by reference.

[0011] 3 shows an alternative configuration of a container handling vehicle 301 with a cantilever structure. Such a vehicle is described in detail, for example, in No. 317366, the contents of which are also incorporated herein by reference.

[0012] 2 may have an footprint that generally covers an area with dimensions in the X and Y directions equal to the lateral extent of a storage column 105, as described, for example, in WO 2015 / 193278 A1, the contents of which are incorporated herein by reference. As used herein, the term "lateral" may mean "horizontal."

[0013] Alternatively, the central hollow container handling vehicle 101 may have an occupied area that is larger than the lateral area defined by the storage columns 105, as disclosed, for example, in WO2014 / 090684A1 (Patent Document 2).

[0014] Rail system 108 typically includes rails with grooves along which vehicle wheels travel. Alternatively, the rails may include upwardly protruding elements, and the vehicle wheels may include flanges to prevent derailment. Collectively, the grooves and upwardly protruding elements are known as tracks. Each rail may include one track, or each rail may include two parallel tracks.

[0015] WO2018146304 (Patent Document 3), the contents of which are incorporated herein by reference, illustrates a typical configuration of a rail system 108 comprising rails and parallel tracks in both the X and Y directions.

[0016] In the skeleton structure 100, most of the columns 105 are storage columns 105, i.e., columns 105 where storage containers 106 are stored in stacks 107. However, some columns 105 may have other purposes. In FIG. 1 , columns 119 and 120 are such dedicated columns used by container handling vehicles 201, 301 to unload and / or load storage containers 106 so that they can be transported to access stations (not shown), where the storage containers 106 can be accessed from outside the skeleton structure 100 or transferred in and out of the skeleton structure 100. In the art, such locations are typically referred to as "ports," and the columns in which the ports are located can be referred to as "port columns" 119, 120. Transport to the access stations can be horizontal, diagonal, and / or vertical. For example, storage containers 106 may be placed in random or dedicated columns 105 within the framework structure 100 and then loaded by any container handling vehicle and transported to port columns 119, 120 for further transport to an access station. Note that the term "diagonal" refers to the transport of storage containers 106 having a rough transport orientation somewhere between horizontal and vertical.

[0017] In FIG. 1 , the first port column 119 may be, for example, a dedicated loading port column where container handling vehicles 201, 301 may unload storage containers 106 to be transported to an access or transfer station, and the second port column 120 may be a dedicated loading port column where container handling vehicles 201, 301 may load storage containers 106 being transported from an access or transfer station.

[0018] An access station may typically be a picking station or a stockpiling station where product items are removed from or placed into storage containers 106. At a picking station or a stockpiling station, the storage containers 106 are typically not removed from the automated storage and retrieval system 1, but are returned to the backbone structure 100 once accessed. Ports can also be used to transfer storage containers to another storage facility (e.g., to another backbone structure or to another automated storage and retrieval system), to a transport vehicle (e.g., a train or large vehicle), or to a production facility.

[0019] A conveyor system comprising conveyors is typically employed to transport storage containers between the port columns 119, 120 and the access stations.

[0020] If the port columns 119, 120 and the access stations are located on different floors, the conveyor system may include a lifting device with a vertical component for vertically transporting the storage containers 106 between the port columns 119, 120 and the access stations.

[0021] The conveyor system may be arranged to transport storage containers 106 between different skeletal structures, for example as described in WO2014 / 075937A1 (Patent Document 4), the contents of which are incorporated herein by reference.

[0022] 1 is to be accessed, one of the container handling vehicles 201, 301 is commanded to retrieve the target storage container 106 from its location and transport it to the loading port column 119. This operation involves moving the container handling vehicle 201, 301 to a location above the storage column 105 in which the target storage container 106 is located, using a lifting device (not shown) on the container handling vehicle 201, 301 to retrieve the storage container 106 from the storage column 105, and transporting the storage container 106 to the loading port column 119. If the target storage container 106 is located deep within the stack 107, i.e., with one or more other storage containers 106 positioned above the target storage container 106, the operation also involves temporarily moving the above-positioned storage container prior to raising the target storage container 106 from the storage column 105. This step, sometimes referred to in the art as "digging," may be performed using the same container handling vehicle that will subsequently be used to transport the target storage container to the unloading port column 119, or using one or more other cooperating container handling vehicles. Alternatively, or in addition, the automated storage and retrieval system 1 may have a dedicated container handling vehicle dedicated to the task of temporarily removing storage containers from storage columns 105. Once the target storage container 106 is removed from storage column 105, the temporarily removed storage container can be repositioned in the original storage column 105. However, the removed storage container may alternatively be relocated to another storage column.

[0023] When a storage container 106 is to be stored in one of the columns 105, one of the container handling vehicles 201, 301 is commanded to load the storage container 106 from the load port column 120 and transport it to a location above the storage column 105 where it is to be stored. After any storage containers located at or above the target location in the storage column stack 107 are removed, the container handling vehicles 201, 301 position the storage container 106 in the desired location. The removed storage container may then be lowered back into the storage column 105 or relocated to another storage column.

[0024] To monitor and control the automated storage and retrieval system 1 (e.g., to monitor and control the locations of the individual storage containers 106 within the skeletal structure 100, the contents of each storage container 106, and the movements of the container handling vehicles 201, 301 so that the desired storage containers 106 can be delivered to the desired locations at the desired times without the container handling vehicles 201, 301 colliding with each other), the automated storage and retrieval system 1 includes a control system 500, which is typically computerized and typically includes a database for tracking the storage containers 106.

[0025] (Prior art method of monitoring errors in storage systems) As can be appreciated, prior art storage and retrieval systems such as those described above are highly automated. The complex logistics of the system and the operation of the autonomous container handling vehicles (also referred to as "robots") are managed by computerized control systems. Such systems, and the robots themselves, are inevitably prone to errors and malfunctions.

[0026] In such prior art storage systems, the control system often comprises several software programs or modules, each responsible for a different aspect of the overall control of the system. One such module is the so-called "exception handler" module 501, which is responsible for identifying, monitoring, and repairing errors or malfunctions in the container handling vehicles.

[0027] The exception handler module can, in many cases, perform the following actions without user intervention: Automatically repairs >97% of repairable robot errors without any interruption to system operation. When a robot reports an error, the exception handler module takes over control of that particular robot, while other robots continue to operate as usual. If a robot is not 100% sure of its location, the exception module may seal off an area of ​​the cell around the malfunctioning robot. The system may operate normally outside the boundaries of the sealed area. The exception module may use the robot's lifting device to search for unique patterns of container depth (in storage columns) within the containment area to detect the robot's location. If needed, another robot can be commanded to generate a unique pattern of container depth to help identify the location of a malfunctioning robot.

[0028] In some cases, identifying the specific cell in which a malfunctioning robot is located (or a vehicle may be between cells) or the exact location of other types of anomalies is a challenge. This latter problem is particularly difficult in the case of very large storage systems with low ceiling heights. With low ceiling heights, all points within a very large surface area appear similar when viewed from above, making visual confirmation of the robot's location difficult (e.g., using a fixed camera). Therefore, manual inspection of the upper surface of the storage system framework by a human inspector is often required. This is a dangerous operation, however, and often requires a costly system shutdown. Therefore, a need exists for additional or alternative means of identifying errors, determining the exact location of a malfunctioning vehicle, or otherwise performing a visual inspection of the storage system.

[0029] (Flying drone) Small aerial drones are commercially available. Examples of such commercially available drones include the fleet of small quadcopters available from drone manufacturer DJI (Shenzen, China). Such drones have become very sophisticated, with sophisticated positioning and obstacle avoidance systems that make drone operation relatively simple and reliable.

[0030] The drone can operate both indoors and outdoors. When outdoors, the drone uses GPS to determine its location. The drone uses GPS information to hover at a fixed position, navigate to a desired location, and return home if communication with the pilot is lost. The drone also has various other sensors: front, rear, top, and bottom collision detectors. Barometric pressure sensors are also used to determine altitude, etc.

[0031] When flying indoors, a GPS signal is often not available. In such situations, drones often use downward-facing optical sensors to identify patterns on the floor in order to hover at a fixed location. [Prior art documents] [Patent documents]

[0032] [Patent Document 1] International Publication No. 2015 / 193278 [Patent Document 2] International Publication No. 2014 / 090684 [Patent Document 3] International Publication No. 2018 / 146304 [Patent Document 4] International Publication No. 2014 / 075937 Summary of the Invention [Means for solving the problem]

[0033] (Summary of the Invention) The present invention is set out and characterized in the independent claims, while the dependent claims describe further characteristics of the invention.

[0034] In one aspect, the present invention relates to a method for visually inspecting storage systems using aerial drones, and in particular to locating, identifying, and inspecting for malfunctioning container handling vehicles or other errors in automated storage and retrieval systems of the type described above.

[0035] In a second aspect, the present invention relates to a method for locating and addressing errors in an automated storage and retrieval system, wherein an exception handler module of a control system communicates with and controls airborne drones to locate and inspect suspected errors in the system, for example, malfunctioning autonomous container handling vehicles.

[0036] In a third phase, a human operator pilots the flying drone and locates and checks for possible errors according to the method.

[0037] The following are exemplary embodiments of steps in a method according to the present invention.

[0038] A vehicle in the system stalls or otherwise reports an error.

[0039] An exception handler module in the control system determines the approximate location of the stalled vehicle and blocks off a large section of the grid surrounding the estimated location.

[0040] The exception handler module issues a command to the drone flight control module to deploy the flying drone.

[0041] The drone flight control module initiates an automatic launch sequence for the drone to rise to a predetermined height, the predetermined height being above the skeletal structure of the storage system but below the ceiling height of the storage and retrieval facility within which the skeletal structure is arranged.

[0042] The drone may have an altitude limiter function that constrains the upper and lower altitudes so that the drone can safely fly in a space above vehicles operating on the upper floors of the framework and below the ceiling.

[0043] Based on the estimated location of the disabled vehicle, the drone control module causes the drone to initiate a search pattern.

[0044] In one embodiment, the drone uses onboard optical sensors to navigate the skeletal grid pattern to the approximate location identified by the exception handler module. The drone may navigate the grid by several means. For example, the drone may use optical sensors to simply count the number of cells as it passes overhead in the X and Y directions and navigate to the given coordinates identified by the exception handler module. Alternatively, a fixed positioning arrangement may help the drone navigate the grid, such as a beacon, location identifier, or other means mounted in a known location (e.g., on the ceiling or on the skeletal structure itself). Such means may have a unique visual identifier, RFD signal, etc. recognizable by the drone. Similarly, the drone may recognize a robot or robots whose exact locations the exception handler module knows, or may identify patterns in relative vehicle positions or container depths.

[0045] Upon arriving at the approximate location of the disabled vehicle, the drone may execute a pre-programmed search pattern to identify and precisely locate the disabled vehicle, or may otherwise identify the disabled vehicle, for example, by a unique identifier on the robot. Alternatively, or in addition, a human operator may assume control of the drone and use a camera mounted on the drone to locate the disabled vehicle or other error and / or perform a visual inspection.

[0046] In another aspect, the disabled vehicle is commanded to transmit a short-range distress signal (e.g., an RFID signal excitable by a signal transmitted from a drone or other means).

[0047] After identifying the exact location of the disabled vehicle, the exception handler module can then redefine a smaller containment area, allowing more of the storage system to continue normal operation.

[0048] After completing its mission, the drone may initiate a return sequence, for example, using a grid pattern or other navigation means to find its way back to its base and land.

[0049] It should be understood that the methods described above may be employed for any type of error that requires a visual inspection, including, for example, inspection of the system for suspected fires or other anomalies, or even routine visual inspections. The present invention provides, for example: (Item 1) 1. A method for monitoring an automated storage and retrieval system (1) of the type comprising a storage grid (104) provided by a framework (100) arranged below a ceiling (412) within a building, comprising: The framework structure (100) comprises a rail system (108) arranged on an upper floor of the framework structure, the rail system comprising a first set (110) of parallel rails arranged in a horizontal plane (P) and extending in a first direction (X), and a second set (111) of parallel rails arranged in the horizontal plane (P) and extending in a second direction (Y) perpendicular to the first direction (X), the first and second sets (110, 111) of rails being arranged in the horizontal plane (P). forming a grid pattern in the storage grid, the grid pattern comprising a plurality of adjacent access openings / grid cells (112), the storage grid defining a plurality of storage columns (105), each storage column arranged to store a respective stack (107) of storage containers (106), the storage columns (105) positioned directly below the rail system (108), each storage column (105) positioned vertically below a respective access opening / grid cell (112); The system comprises: - a plurality of container handling vehicles (201 / 301) operable on said rail system (108) to collect storage containers (106) from the storage columns (105) and return the storage containers (106) to the storage columns (105); - a control system (500) for monitoring and controlling said automated grid storage and retrieval system; wherein the method further comprises: a. launching an airborne drone (400) equipped with a camera (415) to a certain altitude within an airspace (408) located between an upper surface (410) of a skeletal structure (100) and said ceiling (412) or a roof obstacle (414) directly below said ceiling; b. Navigating the drone (400) to a location where there is a suspected anomaly in the system or other aspect of the system requiring inspection; c. using the drone to locate the anomaly or the aspect of the system requiring inspection; d. using a camera on the flying drone to conduct a visual inspection of the anomaly or the aspect of the system requiring inspection; wherein the control system (500) comprises: a. an exception handler module (501) responsible for identifying and attempting to correct anomalies in the operation of the storage system; b. a flight control module (502) responsible for controlling the flight of the drone (400); wherein the flight control module directs flight of the drone in response to instructions received from the exception handler module (501). (Item 2) 2. The method of claim 1, wherein the flight control module comprises instructions for restricting the altitude of the drone during horizontal flight to the airspace between the upper surface (410) of the skeletal structure and the ceiling (410). (Item 3) 10. The method of claim 1, wherein the drone is guided to the suspected anomaly by recognizing known patterns in the positioning of container handling vehicles. (Item 4) 5. The method of claim 1, wherein the drone is guided to the suspected anomaly by counting grid cells in the X and Y directions and arrives at the grid coordinate identified by the exception handler module (501). (Item 5) 10. The method of claim 9, wherein the exception handler module defines a first, larger containment area (422) of the grid surrounding the suspected location of the anomaly, and no container handling vehicles are allowed to operate inside the containment area (422), and the exception handler module defines a second, smaller containment area (426) based on input received from the drone. (Item 6) 10. The method of claim 1, wherein the flight control module instructs the drone to execute a pre-programmed search pattern to locate the anomaly. (Item 7) 10. The method of any one of the preceding items, wherein the anomaly is a malfunctioning container handling vehicle and the particular cell of the grid in which the vehicle is located is unknown to the exception handler module. (Item 8) 10. The method of claim 1, wherein a human pilot assumes flight control of the drone and performs a visual inspection for the anomaly. [Brief explanation of the drawings]

[0050] BRIEF DESCRIPTION OF THE DRAWINGS The following drawings are included to facilitate an understanding of the invention, and illustrate embodiments of the invention, which are herein described by way of example only.

[0051] [Figure 1] FIG. 1 is a perspective view of a prior art automated storage and retrieval system for storing and retrieving containers.

[0052] [Figure 2] 2 and 3 are perspective views showing a prior art container handling vehicle. [Figure 3] 2 and 3 are perspective views showing a prior art container handling vehicle.

[0053] [Figure 4] FIG. 4 is a perspective view of a skeleton structure of a prior art automated storage and retrieval system, illustrating a flying drone taking off from a launch pad and hovering between the ceiling and the upper surface of the skeleton structure.

[0054] [Figure 5] FIG. 5 is a perspective view of a skeletal structure arranged below a ceiling having girders or other obstacles, as well as a schematic representation of a human drone operator and drone operating station.

[0055] [Figure 6] Figure 6 is a side elevation view showing a drone using sensors to avoid contact with the ceiling / girders and skeletal structure.

[0056] [Figure 7] FIG. 7 is a perspective view illustrating a drone flying at a relatively low altitude above a section of the grid that is devoid of container handling vehicles.

[0057] [Figure 8] FIG. 8 is a perspective view of a framework showing multiple container handling vehicles arranged in a recognizable pattern.

[0058] [Figure 9] FIG. 9 is a top view illustrating a drone performing a search pattern and a section of the grid being blocked off by an exception handling module.

[0059] [Figure 10] FIG. 10 is a top view illustrating a drone locating a container handling vehicle by detecting a short-range distress signal. DETAILED DESCRIPTION OF THE INVENTION

[0060] (Detailed Description of the Invention) In the following, embodiments of the present invention will be discussed in more detail with reference to the accompanying drawings, which should be understood, however, that the drawings are not intended to limit the invention to the subject matter depicted in the drawings.

[0061] The present invention comprises an automated storage and retrieval system 1, which comprises a skeleton structure 100 constructed in accordance with the prior art as described above and illustrated in Figures 1 to 3, i.e., several upright members 102 and several horizontal members 103 supported by the upright members 102, and further comprises a first upper rail system 108 in the X and Y directions on which the container handling vehicles 201 / 302 operate.

[0062] Skeleton structure 100 can be of any size. In particular, it should be understood that the skeletal structure can be significantly wider and / or longer and / or deeper than that disclosed in Figure 1. For example, skeletal structure 100 may have a horizontal extent of greater than 700 x 700 columns and a storage depth of greater than 12 containers.

[0063] The operation of the automated storage and retrieval system is directed and monitored by a computerized control system 500 having an exception handler module 501 as shown conceptually in FIG. 1, which is responsible, among other things, for detecting and correcting abnormalities or errors in the functioning of the container handling vehicles, such as, for example, defining a containment area of ​​the grid surrounding a malfunctioning vehicle.

[0064] One embodiment of an automated storage and retrieval system, including a method for monitoring such a system according to the present invention, will now be discussed in more detail with reference to FIGS.

[0065] The present invention includes utilizing an aerial drone 400 to monitor the operation of the storage system as well as to locate and visually inspect various aspects of the system (e.g., locating and inspecting a disabled container handling vehicle 201A / 301A). As used herein, the term "aerial drone" refers to an unmanned, remotely operated rotorcraft, such as a helicopter or quadcopter, that is maintained aloft partially or entirely by lifting surfaces (rotors) that rotate about a vertical axis. The drone 400 can be operated manually or remotely, for example, by a human operator 402 operating in a flight control station 404, as shown in FIG. 5. In another aspect, the flight of the drone may be automated and controlled, for example, by a flight control module 502 of a control system 500, in communication with, for example, an exception handler module 501.

[0066] The present invention will be described in connection with one illustrative embodiment of monitoring a system, namely, locating and visually inspecting a malfunctioning container handling vehicle 201A / 301A. However, it should be understood that aerial drones may also be utilized to locate and inspect many other types of errors and anomalies, such as inspecting suspected defects in the framework structure, locating suspected fires, or for routine visual inspection of the system.

[0067] As shown in Figure 4, drone 400 is launched from launch pad 406. The drone may be controlled by a flight control module 502 or may be controlled by a human pilot 402. Drone 400 is flown to an altitude within airspace 408 between an upper surface 410 of a skeletal structure and a ceiling 412 of a building in which the storage system is disposed. As shown in Figure 5, airspace 408 may be the altitude between upper surface 410 and an obstacle, such as a girder 414, attached to ceiling 412.

[0068] 6, drone 400 may include a camera 415 (not shown) and obstacle avoidance sensors 416 arranged to maintain the altitude of the drone within airspace 408. The drone may have pre-programmed altitude limits, for example, controlled by flight control module 502.

[0069] The drone is sent out on a flight mission to locate the disabled vehicle 201A / 301A. As can be seen from Figure 7, the upper surface of the skeletal structure may have large areas without an operating vehicle or other visual cues for visual confirmation of the drone's exact location at a given point during the flight mission. Therefore, the method of the present invention provides a navigation means that allows the drone to navigate above the skeletal structure and determine its exact location.

[0070] 8 conceptually illustrates one possible method for determining the precise location of a drone at any given point during a flight mission, the method including communicating with a control system 500 or exception handler module 500 that knows the precise location of the operating vehicle 201 / 301. The operating vehicle may emit a location signal 418 that is detectable by the drone 400. Alternatively, the drone 400 may be equipped with a camera arranged to detect multiple vehicles arranged in a particular pattern 420 at known locations recognizable by the exception handler module 501.

[0071] Alternatively, the drone 400 may be instructed to fly above the surface of the skeletal structure and count cells within the grid structure in the X and Y directions until the drone arrives at the coordinates of the first large containment area 422 shown in FIG. 9, the first large containment area 422 being defined by the exception handler module 502 and based on the estimated location of the disabled vehicle 201A / 301A.

[0072] As shown in FIG. 9, upon arriving at a first containment area 422, the drone 400 may be commanded to execute a preprogrammed search pattern 424. As the drone executes the search pattern, an exception handler module may periodically redefine a second, smaller containment area 426. The drone continues along its search pattern until it finally visually locates the disabled vehicle 201A / 301A, at which point the exception handler module defines a third, most restrictive containment area 428. As shown in FIG. 10, the drone 400 may alternatively detect a distress signal 430 emitted by the disabled vehicle.

[0073] Upon arriving at its intended location, the drone may perform a visual inspection, for example, by recording still images or video using its camera. Alternatively, a human operator 402 may perform the visual inspection.

[0074] Upon completion of the mission, the drone 400 returns to its launch pad 406 by a pre-programmed return command, by counting grid cells again, or with assistance from a human pilot.

[0075] In the foregoing description, various aspects of an inspection method employing an aerial drone have been described. However, this description is not intended to be construed in a limiting sense. Various modifications and variations of the illustrative embodiments, as well as other embodiments of the system, that are obvious to those skilled in the art to which the disclosed subject matter pertains are deemed to be within the scope of the present invention.

[0076] (List of reference numbers) [Table 1-1] [Table 1-2]

Claims

1. 1. A method for monitoring an automated storage and retrieval system (1) of the type comprising a storage grid (104) provided by a framework structure (100) arranged below a ceiling (412) in a building, comprising: The framework (100) comprises a rail system; The automated storage and retrieval system comprises: - a plurality of container handling vehicles (201 / 301) operating on said rail system (108) to collect storage containers (106) from the storage columns (105) and to return the storage containers (106) to the storage columns (105); - a control system (500) for monitoring and controlling said automated storage and retrieval system, said control system (500) comprising: an exception handler module (501) responsible for identifying and attempting to correct anomalies in the operation of the automated storage and retrieval system; b. a flight control module (502) responsible for controlling the flight of the flying drone (400) in response to commands received from the exception handler module (501); a control system (500) comprising: Furthermore, The method comprises: a. launching the flying drone (400) equipped with a camera (415) to an altitude within an airspace (408) located between an upper surface (410) of a skeletal structure (100) and the ceiling (412) or a roof obstacle (414) directly below the ceiling; b. Navigating the drone (400) to a suspected anomaly within the automated storage and retrieval system, the anomaly being a malfunctioning container handling vehicle, the particular cell of the grid in which the malfunctioning vehicle is located being unknown to the exception handler module (501); c. using the drone to locate the anomaly; d. conducting a visual inspection of the anomaly using the camera of the flying drone; A method comprising:

2. The framework structure (100) comprises a rail system (108) arranged on an upper floor of the framework structure, the rail system comprising a first set (110) of parallel rails arranged in a horizontal plane (P) and extending in a first direction (X), and a second set (111) of parallel rails arranged in the horizontal plane (P) and extending in a second direction (Y) perpendicular to the first direction (X), the first and second sets (110, 111) of rails being arranged in a grid in the horizontal plane (P).

2. The method of claim 1, wherein the storage grid defines a plurality of storage columns arranged to store a respective stack of storage containers, the storage columns being positioned directly below the rail system, and each storage column being positioned vertically below a respective access opening / grid cell.

3. 3. The method of claim 1 or claim 2, wherein the flight control module comprises instructions for restricting the altitude of the drone during horizontal flight to the airspace between the upper surface (410) of the skeletal structure and the ceiling (412).

4. 4. The method of claim 1, wherein the drone is guided to the suspected location of the anomaly by recognizing known patterns in the positioning of container handling vehicles.

5. 5. The method of claim 1, wherein the drone is guided to the suspected location of the anomaly by counting grid cells in a first direction (X) and a second direction (Y) until it arrives at a grid coordinate identified by the exception handler module (501).

6. 6. The method of claim 1, wherein the exception handler module defines a first, larger containment area (422) of the grid surrounding the suspected location of the anomaly, and wherein no container handling vehicles are allowed to operate inside the containment area (422), and the exception handler module defines a second, smaller containment area (426) based on input received from the drone.

7. The method of any one of claims 1 to 6, wherein the flight control module commands the drone to execute a pre-programmed search pattern to locate the anomaly.

8. 8. The method of claim 1, wherein a human operator assumes flight control of the drone and performs a visual inspection for anomalies.

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