System for monitoring inventory location within a warehouse
The system uses a mobile sensor system with RFID antennas to track inventory in warehouses by distinguishing between stationary and movable items, offering accurate location monitoring and visual representation, addressing the challenge of inventory tracking in large warehouses.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-02-27
- Publication Date
- 2026-03-04
AI Technical Summary
Keeping track of inventory in large warehouses is difficult, especially when containers accumulate in specific areas, making it challenging to identify where this occurs.
A system comprising a mobile sensor system with an RFID antenna attached to a vehicle within the warehouse, which processes RFID signaling to determine the location of both stationary infrastructure and movable inventory items, using signal strength comparisons and known locations of stationary RFID antennas to provide accurate inventory location signaling.
Provides a convenient and efficient method to monitor inventory location within a warehouse, allowing visual representation on a map and identifying areas of unintentional accumulation, with improved accuracy and energy efficiency through directional antennas and periodic scanning.
Smart Images
Figure 2026507685000001_ABST
Abstract
Description
[Technical Field]
[0001] FIELD OF THE DISCLOSURE The present disclosure relates to systems and methods for monitoring the location of inventory within a warehouse, and in particular to systems and methods that use RFID antennas. Summary of the Invention [Means for solving the problem]
[0002] According to a first aspect of the present disclosure, there is provided a system for monitoring inventory location in a warehouse, the system comprising: A mobile sensor system to be attached to a vehicle moving within the warehouse, the mobile sensor system comprising: 1. An RFID antenna, comprising: transmitting an RFID scan signal to excite one or more RFID tags in the vicinity of the RFID antenna; and providing RFID signaling representative of one or more RFID tag signals received from one or more RFID tags; The system for monitoring inventory location within a warehouse comprises: processing the RFID signaling to determine one or more infrastructure RFID tag identifiers associated with RFID tags associated with stationary infrastructure items within the warehouse; determining an antenna location based on the determined one or more infrastructure RFID tag identifiers, the antenna location representing the location of the RFID antenna within the warehouse at the time the RFID signaling was acquired; processing the RFID signaling to determine one or more inventory RFID tag identifiers associated with RFID tags associated with movable items of inventory within the warehouse; Associating the inventory RFID tag identifier with the determined antenna location for RFID signaling acquired at approximately the same time; and providing inventory location signaling based on the association between the inventory RFID tag identifier and the antenna location.
[0003] Advantageously, such a system can provide a convenient and efficient method of monitoring the location of inventory within a warehouse.
[0004] The inventory location signaling may include the location of each detected inventory item so that the location of these inventory items can be visually represented on a map of the warehouse.
[0005] Stationary infrastructure items within a warehouse may include one or more of supports, barriers, racking legs, post caps, gateposts, and shelves.
[0006] The controller processing the RFID signaling to determine first infrastructure RFID tag identifiers and second infrastructure RFID tag identifiers associated with RFID tags associated with different items of stationary infrastructure within the warehouse; comparing a signal strength of the RFID tag signal for the first infrastructure RFID tag identifier to the signal strength of the RFID tag signal for the second infrastructure RFID tag identifier to determine whether the RFID antenna is closer to the RFID tag associated with the first infrastructure RFID tag identifier or closer to the RFID tag associated with the second infrastructure RFID tag identifier; providing the inventory location signaling based on the comparison of the signal strengths.
[0007] The system comprises: The warehouse further comprises a stationary sensor system attached to any stationary item of infrastructure within the warehouse, the stationary sensor system comprising: the stationary RFID antenna installed at a known location within the warehouse, the RFID antenna comprising: transmitting an RFID scan signal to excite one or more RFID tags in the vicinity of the RFID antenna; providing RFID signaling representative of one or more RFID tag signals received from one or more RFID tags; The controller: processing the RFID signaling from the stationary RFID antenna to determine one or more inventory RFID tag identifiers associated with RFID tags associated with movable items of inventory; Associating the inventory RFID tag identifier determined from the RFID signaling provided by the stationary RFID antenna with the known location of the stationary RFID antenna; providing the inventory location signaling based on the association between the inventory RFID tag identifier determined from the RFID signaling provided by the stationary RFID antenna and the known location of the stationary RFID antenna.
[0008] The mobile sensor system includes: transmitting a second RFID scan signal to excite one or more RFID tags in proximity to the RFID antenna; and providing second RFID signaling representative of one or more RFID tag signals received from the one or more RFID tags.
[0009] The controller processing the second RFID signaling to determine one or more infrastructure RFID tag identifiers associated with RFID tags associated with items of stationary infrastructure within the warehouse; determining a second antenna location based on the determined one or more infrastructure RFID tag identifiers, the second antenna location representing the second RFID antenna location within the warehouse at the time the second RFID signaling was acquired; processing the second RFID signaling to determine one or more inventory RFID tag identifiers associated with RFID tags associated with movable items of inventory within the warehouse; Associating the inventory RFID tag identifier with the determined second antenna location for a second RFID signaling acquired at approximately the same time; providing the inventory location signaling based on the association between the inventory RFID tag identifier and the second antenna location.
[0010] The RFID antenna may be configured to provide subsequent RFID signaling in response to subsequent transmission of the RFID scan signal. processing the subsequent RFID signaling to determine one or more subsequent infrastructure RFID tag identifiers associated with RFID tags associated with stationary infrastructure items within the warehouse; determining a subsequent antenna location based on the determined one or more subsequent infrastructure RFID tag identifiers, the subsequent antenna location representing the location of the RFID antenna within the warehouse at the time the subsequent RFID signaling was acquired; processing the subsequent RFID signaling to determine one or more subsequent inventory RFID tag identifiers associated with RFID tags associated with movable items of inventory within the warehouse; Associating subsequent inventory RFID tag identifiers with subsequent antenna locations for subsequent RFID signaling acquired at approximately the same time; determine whether the inventory RFID tag identifier and the subsequent inventory RFID tag identifier are associated with the same RFID tag but with different antenna locations, and if so, provide an output signal indicating that the mobile inventory item associated with the RFID tag is in transit with the vehicle to which the mobile sensor system is attached.
[0011] The controller It may be further configured to control the RFID antenna to periodically transmit an RFID scan signal.
[0012] The controller may be configured to set a frequency at which the RFID antenna transmits an RFID scan signal based on the speed of the vehicle to which the mobile sensor system is attached.
[0013] The RFID tag may be passive.
[0014] The controller The RFID tag signal may be configured to be determined to be present in the RFID signaling only if the RFID tag signal has a signal strength above a threshold.
[0015] According to a further aspect of the present disclosure, there is provided a method for monitoring the location of inventory in a warehouse, the method comprising: providing an RFID antenna mounted on a vehicle moving within the warehouse, the RFID antenna transmitting an RFID scan signal to excite one or more RFID tags in a vicinity of the RFID antenna, and RFID signaling representative of one or more RFID tag signals received from the one or more RFID tags; processing the RFID signaling to determine one or more infrastructure RFID tag identifiers associated with RFID tags associated with stationary infrastructure items within the warehouse; determining an antenna location based on the determined one or more infrastructure RFID tag identifiers, the antenna location representing the location of the RFID antenna within the warehouse at the time the RFID signaling was acquired; processing the RFID signaling to determine one or more inventory RFID tag identifiers associated with RFID tags associated with movable items of inventory within the warehouse; Associating the inventory RFID tag identifier with the determined antenna location for RFID signaling acquired at approximately the same time; and providing inventory location signaling based on the association between the inventory RFID tag identifier and the antenna location.
[0016] A computer program may be provided that, when executed on a computer, causes the computer to configure any apparatus, including a controller, system, or device disclosed herein, or to perform any method disclosed herein. The computer program may be software implemented, and the computer may be considered any suitable hardware, including, by way of non-limiting example, a digital signal processor, a microcontroller, and a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electronically erasable programmable read-only memory (EEPROM). The software may also be an assembly program.
[0017] The computer program may be provided on a computer-readable medium, which may be a physical computer-readable medium, such as a disk or memory device, or may be embodied as a transient signal. Such a transient signal may be downloaded from a network, including downloading from the Internet. One or more non-transitory computer-readable storage media may be provided that store computer-executable instructions that, when executed by a computing system, cause the computing system to perform any of the methods disclosed herein.
[0018] One or more embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]
[0019] [Figure 1] 1 shows a schematic plan view of part of the interior of a warehouse. [Figure 2] 1 illustrates an example embodiment of a system for monitoring inventory location within a warehouse. [Figure 3] 1 illustrates another example embodiment of a system for monitoring inventory location within a warehouse. [Figure 4] 1 illustrates a further example embodiment of a system for monitoring inventory location within a warehouse. [Figure 5A] 1 illustrates an example embodiment of a system capable of identifying inventory in transit in a forklift truck equipped with a mobile sensor system. [Figure 5B] 1 illustrates an example embodiment of a system capable of identifying inventory in transit in a forklift truck equipped with a mobile sensor system. [Figure 6] 1 illustrates an example embodiment of a method for monitoring inventory location within a warehouse. DETAILED DESCRIPTION OF THE INVENTION
[0020] Keeping track of inventory in a warehouse can be difficult, especially in very large warehouses. In some situations, containers (such as totes, boxes, or pallets) that store multiple inventory items can accumulate in a particular area of the warehouse. Identifying that this is happening and where it is occurring can be difficult.
[0021] FIG. 1 illustrates a schematic plan view of a portion of the interior of a warehouse, which is a suitable environment for the systems and methods described herein. FIG. 1 illustrates six banks of racking 101 with aisles 102 between each bank 101. As shown in FIG. 1, a forklift truck (FLT) 108 can travel along the aisles to access inventory stored in different banks 101 of racking. Each bank 101 of racking has a number of racking legs 103. The racking legs 103 are vertical supports used to support shelves or pallets. The banks 101 of racking may also include beams (which are generally horizontal) and / or braces (which extend generally diagonally relative to the ground).
[0022] 1 also shows that a portion of the warehouse is designated as a pedestrian aisle 104. The pedestrian aisle 104 is separated from the racking end aisle by a barrier 105. In this example, the barrier 105 is shown as including a plurality of spaced apart posts 106 with rails 107 joining most of the adjacent posts 106. Pedestrian access points 109 are shown as gaps in the barrier that pedestrians can walk through to travel between the pedestrian aisle 104 and the portion of the warehouse where the FLT 108 operates.
[0023] Each of the posts 106, barriers 105, racking legs 103, and bank of racking 101 are examples of stationary items of warehouse infrastructure according to the present disclosure. In addition, one or more of post caps (i.e., caps on posts), gate posts, shelves, and any other barriers or dividers between different regions within a warehouse (including barriers between different inventory storage areas) can also be considered stationary items of warehouse infrastructure.
[0024] 2 illustrates an example embodiment of a system 209 for monitoring the location of inventory 215 within a warehouse. The system 209 includes a mobile sensor system 212 mounted on a vehicle that travels within the warehouse. In this example, the vehicle is a forklift truck (FLT) 210. The mobile sensor system 212 may be powered by a battery installed on the FLT 210. The system 209 also includes a controller 213 that processes signaling received from the mobile sensor system 212 to determine the location of the inventory 215 within the warehouse, as described below. It will be understood that some or all of the functions of the controller 213 may be performed by one or more devices installed on the FLT 210 and / or some or all of the functions of the controller 213 may be performed by one or more devices remote from the FLT 210.
[0025] Mobile sensor system 212 includes an RFID antenna 211, which is shown transmitting an RFID scan signal 216 to excite one or more RFID tags in the vicinity of RFID antenna 211. This may also be referred to as an RFID scanning RFID antenna 211. In this example, RFID antenna 211 is directional, transmitting RFID scan signal 216 in a particular direction relative to FLT 210. In other examples, RFID antenna 211 may not be directional.
[0026] Any RFID tags 219, 220 energized by the RFID scan signal 216 transmit RFID tag signals 217, 218 in response to the energization, as is known in the art. Two types of RFID tags are shown in FIG. 2: RFID tags 220 associated with movable items of warehouse inventory 215 and RFID tags 219 associated with items of stationary warehouse infrastructure 221. The movable items of warehouse inventory 215 may be individual inventory items, packages of multiple inventory items, and / or inventory containers such as totes or pallets. The stationary warehouse infrastructure item shown in FIG. 2 is a support pole 221. As described below, the two different types of RFID tags 219, 220 may be provided with different identifiers provided as part of the RFID tag signals 217, 218 to distinguish them from one another.
[0027] In this example, the RFID tags 219, 220 are passive. This is advantageous because there is no need to provide batteries for the RFID tags 219, 220, and therefore no need to periodically recharge or replace any such batteries. Furthermore, in this example, the RFID tags 219, 220 are ultra-high frequency (UHF) tags.
[0028] The RFID antenna 211 then provides RFID signaling 214 to the controller 213. The RFID signaling 214 represents one or more RFID tag signals 217, 218 received from one or more RFID tags 219, 220.
[0029] The controller 213 processes the RFID signaling 214 to determine one or more infrastructure RFID tag identifiers associated with the RFID tags 219 associated with items of stationary infrastructure 221 within the warehouse. In one example, this may be done by the controller 213 using a lookup table or database to look up the RFID tag identifier received as part of the RFID tag signals 217, 218 and determine whether it is associated with an item of stationary infrastructure 221 within the warehouse. If so, the RFID tag identifier is considered to be an infrastructure RFID tag identifier.
[0030] The controller 213 can then determine an antenna location based on the determined one or more infrastructure RFID tag identifiers. The antenna location represents the location of the RFID antenna 211 within the warehouse at the time the RFID signaling is acquired. In one example, this can be accomplished by the controller accessing a lookup table or database stored in computer memory. The lookup table or database includes the location of each item of stationary infrastructure 221 within the warehouse and its associated infrastructure RFID tag identifier. The location can be provided as a set of coordinates or in any suitable manner. If only a single infrastructure RFID tag identifier is identified in the RFID signaling 214, the antenna location can simply be set equal to the location of the associated item of stationary infrastructure 221. If multiple infrastructure RFID tag identifiers are identified in the RFID signaling 214, the antenna location can be set based on a combination of the locations of the associated items of stationary infrastructure 221. For example, the controller 213 can calculate a mathematical average of the multiple locations of the items of stationary infrastructure 221.
[0031] One way that the controller 213 can determine the antenna location when multiple infrastructure RFID tag identifiers have been identified is by using the signal strength / power of the received RFID tag signal 217 associated with each infrastructure RFID tag identifier. One example of how signal strength can be represented is as a received signal strength indicator (RSSI) for the received RFID tag signal 217. The controller 213 can compare the signal strength of the RFID tag signal 217 corresponding to a first infrastructure RFID tag identifier with the signal strength of the RFID tag signal 217 corresponding to a second infrastructure RFID tag identifier to determine whether the RFID antenna 211 is closer to the RFID tag 219 associated with the first infrastructure RFID tag identifier or the RFID tag 219 associated with the second infrastructure RFID tag identifier. By comparing the signal strengths in this manner, the controller 213 can determine the relative location of the RFID antenna 211. For example, if the locations associated with the first and second infrastructure RFID tag identifiers are offset along a first dimension, the controller 213 may determine that the RFID antenna is closer to one of the first and second infrastructure RFID tag identifiers whose RFID tag signal 217 is strongest.
[0032] The controller 213 may also process the RFID signaling 214 received from the RFID antenna 211 to determine one or more inventory RFID tag identifiers associated with the RFID tags 220 associated with movable items of inventory 215 within the warehouse. Similar to what was discussed above, the controller 213 may use a lookup table or database to look up the RFID tag identifier received as part of the RFID tag signals 217, 218 to determine whether it is associated with a movable item of inventory 215. If so, the RFID tag identifier is considered to be an inventory RFID tag identifier.
[0033] Once the controller 213 distinguishes between infrastructure RFID tag identifiers (associated with items in the stationary infrastructure 221) and inventory RFID tag identifiers (associated with movable items in the inventory 215), it can determine the location of the inventory within the warehouse. To do this, the controller 213 associates the inventory RFID tag identifiers with the determined antenna positions for RFID signaling 214 acquired at approximately the same time. This can include RFID signaling 214 acquired at the exact same time (e.g., as part of the same RFID scan) or with at least a minimal time difference, such as less than 1, 5, or 10 seconds apart.
[0034] The controller 213 can then provide inventory location signaling 222 based on the association between the inventory RFID tag identifiers and the antenna locations. The inventory location signaling 222 can be implemented in any of several ways to represent the location of the inventory 215 within the warehouse. For example, the inventory location signaling 222 can include the location of each detected item of inventory 215, where the location of these items of inventory can be visually represented on a map of the warehouse or in an inventory list with inventory locations. In this way, a graphical representation can be provided of where the detected inventory is located within the warehouse.
[0035] In instances where inventory RFID tag identifiers are associated with movable totes / pallets within a warehouse, providing inventory location signaling 222 can be particularly useful for identifying areas of unintentional accumulation of (potentially empty) totes / pallets, which may otherwise be particularly difficult to identify the location of in a large, highly automated warehouse.
[0036] 3 and 4 are diagrams further illustrating an example embodiment of a system for monitoring inventory location within a warehouse.
[0037] In Figure 3, FLT 310 is shown within a warehouse. Inventory 315 is shown within an area surrounded by various stationary infrastructure items within the warehouse, one or more of which may be equipped with RFID tags (not shown). In this example, the stationary infrastructure items shown are posts 321, barriers 324, and post caps 323. In other examples, one or more of the following stationary infrastructure items within the warehouse may also be provided with associated RFID tags: gate posts, shelves, and racking legs.
[0038] The FLT 310 includes an RFID antenna 311 that transmits an RFID scan signal 316 in a manner similar to that described for FIG. 2 to excite RFID tags associated with items of inventory 315 and stationary infrastructure 321, 323, 324 within the warehouse.
[0039] Also in Figure 3, the system for monitoring the location of inventory 315 within the warehouse includes stationary sensor system 340. Stationary sensor system 340 may be mounted to a wall of the warehouse (as shown) or to any stationary item of infrastructure within the warehouse. Stationary sensor system 340 also includes RFID antennas (not shown), which are in locations known to the system. For example, the location of each stationary RFID antenna may be stored in memory upon installation of stationary sensor system 340. Stationary sensor system 340 may be powered by a mains power source.
[0040] Similar to the RFID antenna 311 of the mobile sensor system, the RFID antenna of the stationary sensor system transmits an RFID scan signal to excite one or more RFID tags in the vicinity of the RFID antenna and provides RFID signaling representative of one or more RFID tag signals received from the one or more RFID tags. A controller of the system for monitoring the location of inventory within a warehouse can then process the RFID signaling from the stationary RFID antenna to determine one or more inventory RFID tag identifiers associated with RFID tags associated with movable items in inventory 315. Because the locations of the stationary RFID antennas are already known to the system, the controller can then associate the inventory RFID tag identifiers with the known stationary RFID antenna locations and provide inventory location signaling based on i) information received from the stationary RFID antennas, i.e., the inventory RFID tag identifiers determined from the RFID signaling provided by the stationary RFID antennas along with the associated stationary RFID antenna locations, and ii) information received from the mobile RFID antenna 311, i.e., the association between the inventory RFID tag identifiers determined from the RFID signaling provided by the mobile RFID antennas and the determined antenna locations.
[0041] In this way, the controller can be provided with information from the stationary RFID antenna that can be used to verify the location of inventory 315 determined by the mobile sensor system. If the controller identifies a discrepancy between the location of any inventory 315 item as determined from the signals provided by the mobile and stationary RFID antennas, the controller can provide a warning to the user indicating that the system is malfunctioning.
[0042] In Figure 4, an FLT 410 is shown having a first RFID antenna 411a and a controller housed within a truck top box 413. The first RFID antenna 411a transmits a first RFID scan signal 416a that excites an RFID tag 420 associated with inventory / totes 415 and also excites an RFID tag associated with a stationary infrastructure item, such as a barrier / post with a post cap 425 attached, as shown in Figure 4. In this manner, the first RFID antenna 411a can provide first RFID signaling.
[0043] 4, the FLT 410 also has a second RFID antenna 411b. The second RFID antenna 411b transmits a second RFID scan signal 416b that can also excite RFID tags associated with inventory / totes and RFID tags associated with stationary infrastructure items. Thus, the second RFID antenna 411b can provide second RFID signaling. The system's controller can process each of the second RFID signaling to determine the location of the inventory item in a similar manner as described above.
[0044] 4, the first RFID antenna 411a and the second RFID antenna 411b are directional and point in opposite directions away from the FLT 410. In this manner, the system for identifying inventory 415 can perform RFID scans with wide coverage.
[0045] In another embodiment, the first RFID antenna 411a and the second RFID antenna 411b can be directional and point in the same direction. As shown in FIG. 4, they are still spaced apart in the first dimension. In such an example, the controller can compare the signal strength of the RFID tag signal in the first RFID signaling with the signal strength of the RFID tag signal in the second RFID signaling to determine the location of the associated tag in the first dimension relative to the FLT 410. By comparing the signal strengths in this manner, the controller can determine whether the associated RFID tag is closer to the first RFID antenna 411a or the second RFID antenna 411b, and therefore, it can determine the relative location of the associated RFID tag in the first dimension (the dimension in which the first RFID antenna 411a and the second RFID antenna 411b are offset). This can improve the accuracy of determining inventory location.
[0046] 5a and 5b illustrate an example embodiment of a system capable of identifying in-transit inventory 515 with a mobile sensor system 512 attached to an FLT 510. FIG. 5a shows the FLT 510 at a first point in time, where the FLT 510 is near a first post 526. FIG. 5b shows the FLT 510 at a second point in time subsequent to the first point in time, where the FLT 510 is near a second post 528. As described above, the mobile sensor system 512 includes an RFID antenna 511 and a controller 513.
[0047] 5a, RFID antenna 511 transmits RFID scan signal 516a at a first time. In response to receiving RFID tag signals 518a, 530 from RFID tags 520, 527 in the vicinity of RFID antenna 511, controller 513 provides RFID signaling 514a to controller 513.
[0048] Controller 513 then processes RFID signaling 514a to determine one or more infrastructure RFID tag identifiers associated with RFID tags 527 associated with items of stationary infrastructure within the warehouse (in FIG. 5a, this is first support post 526). Similar to what was described above with reference to FIG. 2, controller 513 can then determine an antenna location based on the determined one or more infrastructure RFID tag identifiers, where the antenna location represents the location of RFID antenna 511 within the warehouse at the time RFID signaling 514a was acquired (i.e., at a first point in time).
[0049] Similarly, controller 513 can process RFID signaling 514a to determine one or more inventory RFID tag identifiers associated with RFID tags 520 associated with movable items of inventory 515 within the warehouse. As shown in FIG. 5a, items of inventory 515 bearing RFID tags 520 are placed on the forks of FLT 510 such that inventory 515 is transported with FLT 510. Controller 513 can then associate the inventory RFID tag identifiers with the antenna positions determined for RFID signaling 514a acquired at a first time point.
[0050] 5b, RFID antenna 511 transmits a subsequent RFID scan signal 516b at a second time. In response to receiving subsequent RFID tag signals 518b, 531 from RFID tags 520, 529 in the vicinity of RFID antenna 511, controller 513 provides subsequent RFID signaling 514b to controller 513.
[0051] Controller 513 then processes subsequent RFID signaling 514b to determine one or more subsequent infrastructure RFID tag identifiers associated with RFID tags 529 associated with items of stationary infrastructure within the warehouse (in FIG. 5b, this is second support 528). Similar to what was described with reference to FIG. 2, controller 513 can then determine a subsequent antenna position based on the determined one or more subsequent infrastructure RFID tag identifiers, where the subsequent antenna position represents the position of RFID antenna 511 within the warehouse when subsequent RFID signaling 514b was acquired (i.e., at a second time point).
[0052] The controller 513 can also process the subsequent RFID signaling 514b to determine one or more subsequent inventory RFID tag identifiers associated with RFID tags 520 associated with movable items of inventory 515 within the warehouse. As shown in Figure 5b, the same items of inventory 515 (bearing the same RFID tags 520) as shown in Figure 5a are still placed on the forks of the FLT 510. The controller 513 can then associate the subsequent inventory RFID tag identifiers with subsequent antenna positions for subsequent RFID signaling acquired at approximately the same time (i.e., at a second point in time).
[0053] The controller 513 may then determine whether the inventory RFID tag identifier (from the initial RFID signaling 514a shown in FIG. 5a) and the subsequent inventory RFID tag identifier (from the subsequent RFID signaling 514b shown in FIG. 5b) are associated with the same RFID tag 520 but with different antenna locations. If they are, the controller may then provide an output signal indicating that the item of mobile inventory 515 associated with the RFID tag 520 is in transit on the FLT 510. Optionally, the controller 513 may provide such an output signal only if there is at least a minimum distance between the antenna location determined for the initial RFID signaling 514a and the antenna location determined for the subsequent RFID signaling 514b. Such a minimum distance may be at least the range of the RFID antenna 511. In this manner, the likelihood of identifying a stationary item of inventory 515 as being in transit may be reduced.
[0054] In some examples, the controller 513 can control the RFID antenna 511 to periodically perform RFID scans. The controller 513 can optionally set a period between successive RFID scans based on the speed of the FLT 510. For example, the controller 513 can receive a vehicle speed signal representing the speed of the FLT 510. A speed sensor associated with the FLT 510 can provide the vehicle speed signal. The controller 513 can then set a period between successive RFID scans based on the vehicle speed signal, such that RFID scans are performed more frequently at relatively high speeds than at relatively low speeds. In this manner, RFID scans can be performed to identify most, if not all, of the inventory 515, while avoiding the need for unnecessarily many RFID scans. This can streamline the energy consumption required for RFID scans. Furthermore, RFID scans can be temporarily suspended when the FLT 510 is stationary.
[0055] In any of the examples disclosed herein, the controller may determine that an RFID tag signal is present in the RFID signaling only if the RFID tag signal has a signal strength greater than a threshold. One example of how signal strength may be represented is as a received signal strength indicator (RSSI) for the received RFID tag signal. In this way, weak RFID tag signals may be excluded from further processing, perhaps because they are too far away to be considered in the vicinity of the RFID antenna.
[0056] FIG. 6 illustrates an example embodiment of a method for monitoring inventory location within a warehouse.
[0057] At step 650, the method includes an RFID antenna mounted on a vehicle moving within the warehouse transmitting an RFID scan signal for exciting one or more RFID tags in proximity to the RFID antenna, and at step 650, the method also involves providing RFID signaling representative of one or more RFID tag signals received from the one or more RFID tags.
[0058] In step 651, the method includes processing the RFID signaling to determine one or more infrastructure RFID tag identifiers associated with RFID tags associated with items of stationary infrastructure within the warehouse. One example of how the infrastructure RFID tag identifiers may be distinguished from RFID tag identifiers not associated with items of stationary infrastructure within the warehouse is described above.
[0059] In step 652, the method includes determining an antenna location based on the determined one or more infrastructure RFID tag identifiers, the antenna location representing the location of the RFID antenna within the warehouse when the RFID signaling was acquired.
[0060] In step 653, the method includes processing the RFID signaling to determine one or more inventory RFID tag identifiers associated with RFID tags associated with items of movable inventory within the warehouse. It will be appreciated that steps 651 and 653 can be performed in either order or simultaneously.
[0061] In step 654, the method includes associating the inventory RFID tag identifiers with the antenna locations determined for the RFID signaling acquired at approximately the same time. Thereafter, in step 655, the method involves providing inventory location signaling based on the association between the inventory RFID tag identifiers and the antenna locations.
Claims
1. 1. A system for monitoring inventory location in a warehouse, the system comprising: A mobile sensor system to be attached to a vehicle moving within the warehouse, the mobile sensor system comprising:
1. An RFID antenna, comprising: transmitting an RFID scan signal to excite one or more RFID tags in the vicinity of the RFID antenna; and providing RFID signaling representative of one or more RFID tag signals received from one or more RFID tags; The system for monitoring the location of the inventory within the warehouse comprises: processing the RFID signaling to determine one or more infrastructure RFID tag identifiers associated with RFID tags associated with stationary infrastructure items within the warehouse; determining an antenna location based on the determined one or more infrastructure RFID tag identifiers, the antenna location representing the location of the RFID antenna within the warehouse at the time the RFID signaling was acquired; processing the RFID signaling to determine one or more inventory RFID tag identifiers associated with RFID tags associated with movable items of inventory within the warehouse; Associating the inventory RFID tag identifier with the determined antenna location for RFID signaling acquired at approximately the same time; providing inventory location signaling based on the association between the inventory RFID tag identifier and the antenna location.
2. 10. The system of claim 1, wherein the inventory location signaling includes the location of each detected inventory item, thereby enabling the locations of these inventory items to be visually represented on a map of the warehouse.
3. The system of claim 1 or claim 2, wherein the items of stationary infrastructure within the warehouse include one or more of supports, barriers, racking legs, post caps, gateposts, and shelves.
4. The controller: processing the RFID signaling to determine first and second infrastructure RFID tag identifiers associated with RFID tags associated with different items of stationary infrastructure within the warehouse; comparing a signal strength of the RFID tag signal for the first infrastructure RFID tag identifier with a signal strength of the RFID tag signal for the second infrastructure RFID tag identifier to determine whether the RFID antenna is closer to the RFID tag associated with the first infrastructure RFID tag identifier or closer to the RFID tag associated with the second infrastructure RFID tag identifier; and providing the inventory location signaling based on the comparison of the signal strengths.
5. The system comprises: The warehouse further comprises a stationary sensor system attached to any stationary item of infrastructure within the warehouse, the stationary sensor system comprising: a stationary RFID antenna installed at a known location within the warehouse, the RFID antenna comprising: transmitting an RFID scan signal to excite one or more RFID tags in the vicinity of the RFID antenna; and providing RFID signaling representative of one or more RFID tag signals received from one or more RFID tags; The controller: processing the RFID signaling from the stationary RFID antenna to determine one or more inventory RFID tag identifiers associated with RFID tags associated with movable items of inventory; Associating the inventory RFID tag identifier determined from the RFID signaling provided by the stationary RFID antenna with the known location of the stationary RFID antenna; and providing the inventory location signaling based on the association between the inventory RFID tag identifier determined from the RFID signaling provided by the stationary RFID antenna and the known location of the stationary RFID antenna.
6. the mobile sensor system, transmitting a second RFID scan signal to excite one or more RFID tags in the vicinity of the RFID antenna; and providing second RFID signaling representative of one or more RFID tag signals received from the one or more RFID tags; The controller: processing the second RFID signaling to determine one or more infrastructure RFID tag identifiers associated with RFID tags associated with items of stationary infrastructure within the warehouse; determining a second antenna location based on the determined one or more infrastructure RFID tag identifiers, the second antenna location representing the location of the second RFID antenna within the warehouse at the time the second RFID signaling was acquired; processing the second RFID signaling to determine one or more inventory RFID tag identifiers associated with RFID tags associated with movable items of inventory within the warehouse; Associating the inventory RFID tag identifier with the determined second antenna location for a second RFID signaling acquired at approximately the same time; 6. The system of claim 1, further configured to: provide the inventory location signaling based on the association between the inventory RFID tag identifier and the second antenna location.
7. The RFID antenna is configured to provide subsequent RFID signaling in response to transmitting a subsequent RFID scan signal; The controller: processing the subsequent RFID signaling to determine one or more subsequent infrastructure RFID tag identifiers associated with RFID tags associated with stationary infrastructure items within the warehouse; determining a subsequent antenna location based on the determined one or more subsequent infrastructure RFID tag identifiers, the subsequent antenna location representing the location of the RFID antenna within the warehouse at the time the subsequent RFID signaling was acquired; processing the subsequent RFID signaling to determine one or more subsequent inventory RFID tag identifiers associated with RFID tags associated with movable items of inventory within the warehouse; Associating subsequent inventory RFID tag identifiers with subsequent antenna locations for subsequent RFID signaling acquired at approximately the same time; 7. The system of claim 1, configured to: determine whether the inventory RFID tag identifier and the subsequent inventory RFID tag identifier are associated with the same RFID tag but different antenna locations; and if so, then provide an output signal indicating that the mobile item of inventory associated with the RFID tag is in transit with the vehicle to which the mobile sensor system is attached.
8. The controller: The system of claim 1 , further configured to control the RFID antenna to periodically transmit an RFID scan signal.
9. The system of claim 8 , wherein the controller is configured to set a frequency at which the RFID antenna transmits an RFID scan signal based on a speed of the vehicle to which the mobile sensor system is attached.
10. 10. The system of any preceding claim, wherein the RFID tag is passive.
11. The controller:
10. The system of claim 1, configured to determine that an RFID tag signal is present in the RFID signaling only if the RFID tag signal has a signal strength above a threshold.
12. 1. A method for monitoring inventory location in a warehouse, said method comprising: providing an RFID antenna mounted on a vehicle moving within the warehouse, the RFID antenna transmitting an RFID scan signal to excite one or more RFID tags in a vicinity of the RFID antenna, and RFID signaling representative of one or more RFID tag signals received from the one or more RFID tags; processing the RFID signaling to determine one or more infrastructure RFID tag identifiers associated with RFID tags associated with stationary infrastructure items within the warehouse; determining an antenna location based on the determined one or more infrastructure RFID tag identifiers, the antenna location representing the location of the RFID antenna within the warehouse at the time the RFID signaling was acquired; processing the RFID signaling to determine one or more inventory RFID tag identifiers associated with RFID tags associated with movable items of inventory within the warehouse; Associating the inventory RFID tag identifier with the determined antenna location for RFID signaling acquired at approximately the same time; providing inventory location signaling based on the association between the inventory RFID tag identifier and the antenna location.
13. A computer program configured to perform the method according to claim 12.