Patent Publication Number: US-2023140219-A1

Title: Item level picking method and system

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority of U.S. provisional application Ser. No. 63/273,461, filed Oct. 29, 2021, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed to order-fulfilment and inventory management, and in particular to picking operations within an order-fulfilment facility. 
     BACKGROUND OF THE INVENTION 
     Order pickers in order fulfilment facilities may not be able to quickly tell the difference between visually similar items that have different stock keeping units (SKUs), or may be confused, tired, or for some other reason unable to easily make distinctions between items presented to them in inventory totes. Some of these are true of both human and robotic order pickers. These common concerns can result in miss-picks or miss-places, which can lead to orders being incorrectly filled. In the event the operator visually identifies the correct item, the operator must then confirm the correct pick, such as by scanning the item with a scanner and/or pressing a physical confirmation button. Such confirmation steps take valuable time to complete. In instances where multiple different SKUs are present in an inventory tote, it is likely that wanted or required items are mixed in with unwanted or not currently required items, which creates the challenge to order picker of trying to discern which item is the wanted item. Additionally, items may be difficult to locate and access in totes with several items when there is no knowledge for the order picker of roughly where in the tote in three-dimensional space the item is likely to be, requiring order pickers to sort through unwanted items to locate the wanted item. It is common for multiple order containers to be present at one time within a workstation and operators may become confused or slowed by having to determine which is the correct container to place an order item into. Misplaced items may lead to miss-shipments and/or wasted time as items must be recovered and placed in the correct location. 
     Robotic picking operators and human operators may both be utilized in order fulfilment operations, with each having inherent advantages as well as inherent disadvantages. Robotic pickers, similar to human pickers, may have difficulties distinguishing between visually similar items, depending on the sophistication of their machine vision. In instances where inventory totes are loaded with multiple heterogeneous items/SKUs that are stacked on top of one another, robotic pickers must typically remove any unwanted items from the tote and set those items aside before continuing to retrieve the wanted item that was obstructed (e.g. beneath) the unwanted item. As such, the picking operations require additional time which decreases throughput and efficiency. Inventory totes are often filled below capacity to prevent overcrowding and obscuring items at the bottom or middle of the tote. Leaving additional capacity permits pickers to more quickly locate items when they are using visual inspection techniques. Underutilized capacity of inventory totes increase the footprint of the facility by requiring additional storage locations to store additional under-filled totes. 
     SUMMARY OF THE INVENTION 
     The present invention provides a system and method for verification of item level order picking at a goods-to-person (GTP) or goods-to-robot (GTR) picking workstation utilizing radio frequency identification (RFID) based item identification of picked and/or placed items without an operator performing a secondary identification process (e.g. scanning a label of the item), as well as item and/or receptacle level tracking within a material handling system or facility. 
     According to one form of the present invention, a method is provided for monitoring, verifying, and/or validating item level order fulfilment operations within an order fulfilment or warehouse facility. The method includes transporting a receptacle or tote containing a plurality of different or heterogeneous inventory items to an order fulfilment workstation. At least some of the inventory items in the receptacle include an RFID tag. Preferably, all of the inventory items in the receptacle and in the entire facility include an RFID tag. The receptacles may also include an RFID tag. Each RFID tag includes an RFID identifier and each unique RFID identifier is assigned to a particular type of inventory item, such that identical items may have the same RFID identifier, but dissimilar items have different RFID identifiers. The method includes locating, within the receptacle, an item required for an order and, once located, an operator (human or robot) retrieves the required item from the receptacle. The method includes verifying that the operator has selected the required item by recognizing a movement of the RFID tag coupled to that item utilizing an RFID reader that is positioned at the workstation. The RFID reader is in communication with a computer of an order management system that controls and directs order fulfilment operations within the facility. The computer receives information from the RFID reader and determines, based on the received information, whether the RFID tag has moved relative to either of the workstation, the receptacle containing the inventory item, and/or the RFID tags of other items in the receptacle. The method may permit inventory totes to be filled to a higher percentage of their capacity, without the concern of slowing pickers down when they must retrieve an item from the significantly filled tote. Thus, the method may enable order fulfilment and warehouse facilities to be confined to smaller footprints, thus saving space and overhead costs. 
     In one aspect, recognizing a movement of the RFID includes recognizing a change in a positional characteristic of the RFID tag, such as an elevation change, a horizontal translation, or a rotation, for example. In another aspect, locating the required item within the receptacle includes detecting the RFID tag of the required item utilizing the radio frequency scanner and may include directing the operator to the required item within the receptacle with a visual/visible, audible, or physical cue such as with a laser light, a heads-up display, a spatial sonification device (e.g. a directional speaker), a wearable device with a haptic feedback function (e.g. a glove with vibratory or haptic feedback), a smart lighting system, and/or electronic feedback (for robotic operators), for example. Alternatively, the operator may manually locate the required item by reaching into the receptacle and making a physical or visual determination to select the item. 
     In still another aspect, once the correct item has been retrieved and verified, the method includes transferring the required item from the receptacle to an assigned order container and subsequently validating that the required item is disposed in the assigned order container by determining that the location of the item&#39;s RFID tag is within an envelope of the assigned order container. Optionally, validating that the required item is disposed in the assigned order container includes determining a location of an RFID tag coupled with the assigned order container and comparing the position of the required item&#39;s RFID tag relative to the envelope of the assigned order container. Preferably, the envelope dimensions of the assigned order container (relative to the container&#39;s RFID tag) are associated with its RFID tag. As such, the RFID reader and computer may determine the position of the assigned order container and its envelope dimensions. However, it will be appreciated that the envelope dimensions may be determined by other acceptable means, such as by capturing image data of the order container with an image capture device (e.g. camera or photoeye) and the computer determining the dimensions of the container with the capture image data, for example. 
     In another form of the present invention, a verification system is provided for monitoring item level order fulfilment operations at an order fulfilment workstation that is in communication with an order management system. The verification system includes a computer in communication with the order management system, a radio frequency identification (RFID) reader in communication with the computer. The RFID reader is operable to read an RFID tag coupled to an inventory item which is present at the workstation (within a sufficient proximity of the RFID reader) and to communicate the RFID identifier information associated from that RFID tag to the computer. The computer determines a location of the inventory item&#39;s RFID tag relative to either the workstation, a receptacle containing the inventory item, and/or RFID tags of other items present in the receptacle. The computer verifies that an operator at the workstation has chosen a particular, correct one of the plurality of inventory items that are present at the workstation by determining a movement of the RFID tag of the correct inventory item. In other words, if the operator selects and moves the correct item and the computer determines that that item&#39;s RFID tag has moved a significant amount, then it is determined that the operator has retrieved the correct item. 
     In one aspect, the computer system controls the order fulfilment workstation and directs item level picking operations of an operator at the order fulfilment workstation. In another aspect, the verification system includes a pick directing device for directing the operator to the location of a particular one of the inventory items at the workstation. Examples of pick directing devices include, but are not limited to, a laser light, a heads-up display, a spatial sonification device, and/or an operator worn haptic feedback device. In terms of robotic operators, the order management system, i.e. computer, controls the robot to accurately direct the robot picker to the required item. 
     In yet another aspect, the computer directs an operator to place the retrieved item in a particular order container (or onto a conveyor or into another inventory tote) and validates that the operator has placed the item in the correct order container by determining that the location of the item&#39;s RFID tag is within an envelope of the correct order container. Optionally, the order container may include an RFID tag with a unique RFID identifier and the RFID reader may read the container&#39;s RFID tag. Utilizing the RFID tag information of the container and inventory item, the computer directs the operator to place the item into the particular order container and to validate that the operator has placed the item in the correct order container by determining that the location of the item&#39;s RFID tag is within an envelope of the correct order container, such as by determining that the item&#39;s RFID tag is in close enough proximity to the container&#39;s RFID tag. Preferably, the envelope of the order container is associated with the container&#39;s RFID tag and that envelope information may be used by the computer to determine that the item is within the envelope of the container. 
     In another form of the present invention, an RFID enabled material handling system for item level material handling operations. The material handling system includes an order management system having a computer for controlling the various components of the material handling system. The material handling system includes an automated storage and retrieval system (ASRS), an automated sorter in transport communication with the ASRS, and several radio frequency identification (RFID) readers positioned proximate or spaced along various or multiple portions of the ASRS and/or the sorter. Each of the RFID readers is in communication with the computer and each is operable to read RFID tags affixed to individual inventory items (or containers or receptacles) as they pass along the material handling system. The individual inventory items must pass by an RFID reader within a sufficient proximity in order for the RFID reader to accurately read the item&#39;s RFID tag. The RFID readers communicate information associated with any read RFID tags to the computer and the computer may then determine a location of the read inventory item&#39;s RFID tag relative to the RFID reader that communicates the RFID tag information to the computer. Based on the determined locations of the RFID tags, and therefore the individual inventory items, the computer controls the ASRS, the sorter, and any upstream, intermediate, or downstream material handling components to direct and transport the inventory item from the ASRS to its required destination downstream of the sorter (e.g. a packing station). 
     In one aspect, the material handling system includes an induct positioned between the ASRS and sorter and in transport communication with each. At least one RFID reader is positioned at or proximate the induct to read RFID tags of inventory items that are present at the induct. The computer system controls the induct to transfer an inventory item between the ASRS and the sorter. The computer may determine a location of an inventory item&#39;s RFID tag relative to the RFID reader at the induct to facilitate handling of the inventory item at the induct and downstream of the induct to ensure that the inventory item reaches its required destination. 
     In another aspect, the induct may be operable to dump all items out of an inventory receptacle (e.g. onto a conveyor surface of the induct) and to forward all of the dumped items from the induct to the sorter. The computer, utilizing information provided one or more of the RFID readers, directs the sorter to transport and transfer any required items to a required downstream process and to direct and transfer any non-required items back into circulation for future order fulfilment processes, such as back into the ASRS for storage until those items are required. 
     Accordingly, the RFID enabled verification system and method and the RFID enabled material handling system of the present invention enhance order picking functions and material handling operations. The verification system and method are particularly well suited for order fulfilment and warehouse facilities in which multiple different SKUs are stored in a single inventory tote such that items in the tote may not be readily visually distinguishable by the picking operator. The verification system and method provide a verification and feedback system without requiring additional verification steps to be taken by the order picker. The system is capable of providing immediate and accurate feedback to an order picker, preferably without the need for the order picker to perform any visual inspection. The verification system may be adapted for use in an RFID enabled material handling system in which individual items (or containers or receptacles) with RFID tags are directed through a facility as a function of their locations proximate RFID readers disposed throughout the facility. In such embodiments, the verification system monitors and directs the components of the facility to transport the item to its destination and the system verifies and validates that each individual item has indeed reached its required destination. 
     These and other objects, advantages, purposes and features of this invention will become apparent upon review of the following specification in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS.  1 A- 1 B  are a diagram of a method for directing, verifying, and validating item level order fulfilment operations, in accordance with the present invention; 
         FIG.  2    is a perspective view of a verification system for an order fulfilment workstation, in accordance with the present invention; 
         FIG.  3    is a diagram of an aspect of the method of  FIGS.  1 A- 1 B ; 
         FIG.  4    is a diagram of an aspect of the method of  FIGS.  1 A- 1 B ; 
         FIG.  5    is a diagram of an aspect of the method of  FIGS.  1 A- 1 B ; 
         FIG.  6    is a diagram of an aspect of the method of  FIGS.  1 A- 1 B ; 
         FIG.  7    is a diagram of an aspect of the method of  FIGS.  1 A- 1 B ; and 
         FIG.  8    is a plan view of a transportation system for an automated order fulfilment facility. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings and the illustrative embodiments depicted therein, systems and methods are provided for directing, verifying, and validating item level picking and placing operations at an order fulfilment workstation and within a material handling facility (e.g. warehouse or order fulfilment facility). An order management system directs the pick operations at the workstation by directing the operator to select items from inventory receptacles or totes present at the workstation in order to fulfil orders requiring particular items present in the totes. The order management system includes an order database containing information including the inventory items in the order fulfilment facility or warehouse facility, pending orders to be fulfilled, and order sequences or pending work order priorities to be assigned to one or more order fulfilment workstations within the facility. The system and method utilize radio frequency identification (RFID), e.g. RFID tags with unique identifiers, on individual inventory items within an order fulfilment facility. The system and method are particularly beneficial for item level order picking operations in which inventory totes contain multiple items (i.e. stock keeping units (SKUs)), and in particular totes having multiple different or heterogeneous items or SKUs (e.g. items of different shapes, sizes, quantities, versions, editions, etc.) in which one or more of the items are slated for picking and one or more of the items are not slated for picking. The system and method guide the operator of the workstation (based on assigned work orders) to locate and acquire a particular item within the tote, to confirm or verify that the operator acquired the correct item, and to validate that the operator places or deposits the item within an assigned order container or another inventory receptacle. The system and method are adaptable for use with both human and robotic pick operators, as will be described in further detail below. Additionally, it is contemplated that the method of verifying an action performed on an item by determining that an RFID tag on the item has moved may be utilized to control order fulfilment systems (e.g. conveyors, sorters, inducts, etc.) to direct individual items (e.g. products, containers, receptacles, totes, etc.) throughout the order fulfilment facility. The verification system may be integrated at a fixed position within a picking workstation, may be integrated with a wearable device worn by an order picker (e.g. a glove, hat, glasses, etc.), coupled to a portion of a robotic picking arm, integrated into inventory totes and order containers, or may be adapted and integrated at other stages of the picking process and/or order fulfilment operations. 
     The system and method track or monitor the location and/or movement of individual items in or around a tote and provide feedback to operators (e.g. order pickers), such as directional feedback or confirmatory feedback. For example, the system and method may guide or direct the operator to the item(s) to be picked or retrieved from a tote that is present at the workstation. Such as by providing information or feedback to the order picker about the location of the item in the tote (e.g. whether the item is in the right quadrant, left half, and/or top, middle, or bottom layer of the tote). Providing location information to the order picker prior to them accessing the tote reduces the time and effort required to search through the tote, visually inspect the items, and possibly eliminate the need for the operator to empty out other unwanted items in order to access wanted items that are otherwise obscured or covered by unwanted items. Once an item is lifted, shifted, rotated, or removed from the tote, the system and method automatically verify and confirm that the item picked is the correct item required for the pending order being fulfilled. In this manner, the system can provide feedback to the operator that a picked item is either the correct item or incorrect item without the need for the operator to have a line of sight of the item in the tote or requiring the operator to verify that they have selected the correct item after removing it from the tote. The system and method may also verify that if an operator selects an incorrect item, that they then subsequently replace the incorrect item before moving to retrieve the correct item. The order management system directs the operator to transfer the selected item from the inventory tote to an assigned order container (e.g. a shipping carton) or to a different inventory tote and the method automatically confirms the placement of the item in the proper order container or tote. 
     RFID tags affixed to each inventory item provide information storage and short-range transmitters for the items, and in this manner, unique RFID identifiers can be assigned to unique inventory items or SKUs. The RFID tag enables an RFID reader and the order management system to match information from the RFID tag of the item against an inventory SKU database to determine the SKU of the item scanned. The SKU can then be compared against the order database. It will be appreciated that one or more of various types and forms of RFID tags or RFID readers may be utilized with the system and method. Some examples of RFID tag types include ultra-high-frequency (UHF) RFID tags, high-frequency (HF) RFID tags, near field communication (NFC) RFID tags, and low-frequency (LF) RFID tags. While RFID tags are a preferred information storage unit for the system and method due to their inherent portability, inconspicuousness, and their ability to remain with the item after it has left the facility (such that it may return to the facility with the RFID tag intact, potentially facilitating efficient return processing), it will be appreciated that other acceptable information storage units may be utilized for the system and method within the facility, such as real-time location systems (RTLS) (e.g. ultra-wide band RTLS, Wi-Fi RTLS, or infrared RTLS). Alternatively or in addition to RFID tag location functionality, the system may be combined with other verification methods, such as weight monitoring of the tote, inspecting the tote with machine vision, or other known methods, to potentially improve the accuracy of the system and method. 
     The order management system includes a computer in communication with the workstation(s) and the RFID reader. The computer is capable of processing the information stored on the RFID tags (as communicated from the RFID reader to the computer) to identity the items in the tote present at the workstation. Accordingly, the computer is capable of determining a relative location of an item in the tote, identifying changes in the location (movement) of items in the tote relative to other items in the tote or relative to the tote itself or the workstation, determining whether an item has been picked or removed from the tote, and determining whether an item has been placed or disposed in a desired location or container (e.g. an order container). The computer of the order management system is programed with computer code, and may comprise one or more processors as well as hardware and software, including for performing the operations discussed herein. 
     An acquisition support system is provided for directing the operator to pick the correct item from the inventory tote. The acquisition support system utilizes the RFID tags on each inventory item and the RFID scanner of the workstation to indicate to an operator the identity of a required item and its location in three-dimensional space within a tote, and is therefore capable of providing guidance or feedback to the operator as to where to locate and pick the required item. A verification support system is provided for identifying which item an operator picks from the inventory tote and is capable of matching the identity and location of the picked item with a database of the order management system to determine whether the correct item was selected by the operator. A disposition or validation support system is provided for confirming whether the operator has placed or disposed the required item in a proper location (e.g. order container or another inventory tote) and the validation support system is capable of providing information or feedback to the order picker as to where to direct the placement of the item in the correct location. 
     While the verification system and method are particularly well suited for human operated goods-to-person (GTP) pick workstations, the system and method are also well suited for use with robotic picking operators at goods-to-robot (GTR) pick workstations. By determining the location of the wanted item within the tote by locating its RFID tag, the robot operator knows ahead of time where the wanted item is in 3D space within the tote. Having this information without the need of image capture devices, the robotic picker may be able to reach into the tote, move unwanted items aside, and retrieve the wanted item without having to wholly remove each unwanted item that is obstructing the wanted item. The robotic picker may include a gripping element or gripper for engaging and retrieving the items from the tote. The gripper may include a RFID reader incorporated thereon which may provide feedback to the robotic picker to direct the gripper of the robotic picker as it approaches the wanted item. The RFID reader may be utilized to provide confirmation that the gripper has approached the correct item and engaged that item, such as by verifying that the gripper is sufficiently close to the RFID tag of the wanted item, thereby verifying that the correct item has been retrieved by the robotic picker. 
     Optionally, the system and method may forgo determining movement of an item to determine if it had been picked or not, but instead includes a proximity detection device along with a grip detection device that are both disposed in a wearable device (e.g. a glove worn on the operator&#39;s hand). The glove with proximity and grip detection is capable of determining proximity of the operator&#39;s hand to the item and determining whether the operator is gripping, or sufficiently closed onto, an item or not. As such, the system is capable of determining whether the operator has picked and/or released the correct item. Some examples of proximity detection devices include induction proximity sensors, photoelectric proximity sensors, electromagnetic proximity sensors (e.g. infrared sensors), and the like. Some examples of grip detection devices include a glove or end effector with multiple resistive sensors enabled and adapted to recognize when an operator is gripping onto an item, i.e. their grip is closed onto an item, as opposed to when the operators grip is open. 
     Referring to the illustrative embodiment of  FIGS.  1 A- 1 B , a method of item level order fulfilment  100  utilizing a verification system  10  ( FIG.  2   ) includes transporting  102  an inventory receptacle  20  containing a plurality of different or heterogeneous inventory items or SKUs to an order fulfilment workstation  12 . At least some of the inventory items in the inventory receptacle  20  include a radio frequency identification (RFID) tag affixed to the respective item. Preferably, all of the inventory items in the inventory receptacle  20  include an RFID tag. Each RFID tag includes stored information including an RFID identifier, and optionally, information about the item to which the tag is affixed. Each unique RFID identifier is assigned to only one particular type of inventory item. In this manner, any identical SKUs present in the receptacle have the same unique RFID identifier as one another, but that RFID identifier is not the same as the RFID identifier of any other dissimilar SKU. Alternatively, it will also be appreciated that the RFID tag of each individual item may have a unique RFID identifier, regardless of whether one or more individual item is identical or shares a SKU with another item. 
     The method includes locating  104 , within the inventory receptacle  20 , an item required for an order and an operator (either human or robot) retrieving  106  the required item from the inventory receptacle  20  ( FIGS.  1 A- 1 B and  3 - 7   ). Locating  104  the required item within the receptacle may include detecting the RFID tag of the required item utilizing the RFID reader  18  and determining with the computer  16  the relative position of that RFID tag relative to either the workstation  12 , the inventory receptacle  20 , or other RFID tags on other items in the inventory tote  20 . The method  100  may include directing the operator to the required item within the inventory receptacle  20  with an indicator, such as a visual/visible, audible, or physical feedback or cue, such as directing an operator to a target direction of an item with the indicator, such as by illuminating a laser light (e.g. pointing the light to the item), providing a virtual representation of the item with a heads-up display, providing a target direction with a spatial sonification device, providing a target direction with a wearable device having a haptic feedback function, lighting a representative position on the outside of the tote to indicate the relative position of the wanted item inside the tote, and/or illustrating the position of the item on a picking station screen, for example ( FIGS.  3 ,  4 , and  6   ). As an example, a human operator may wear a pair of glasses  22  with a heads-up display (HUD) and the display may signal different colors for items at different elevations (e.g. green (indicated in  FIG.  4    with a straight line at  104 ) for items near the top of the tote, yellow (indicated in  FIG.  4    with a dashed line at  104 ) for items near the middle, and red (indicated in  FIG.  4    with a dot-dash line at  104 ) for items near the bottom). The system  10  may be operable to recognize and indicate, via the HUD, positions of the multiple items at one time, such as when two or more items are needed from a present inventory tote  20  ( FIG.  4   ). For robotic operators, the computer directs the movement of the robot to the location of the required item using electronic control information (e.g. spatial coordinates, etc.). Directing the operator with visual/visible, audible, physical, or electronic feedback may reduce the time necessary for an operator to locate the required item and thereby improve the operator&#39;s efficiency and accuracy. Optionally, augmented reality or other visual indicators may provide the operator with visual information indicating where his hand/finger is located relative to where the item is located in the tote (i.e. how close to their hand is to the targeted item) during the item retrieval operation. 
     Once the operator has retrieved or moved the required item, the method  100  includes verifying  108  that the operator has correctly selected the required item by recognizing  110  a movement of the RFID tag affixed to that item with an RFID reader or sensor positioned at the workstation  12 . The RFID reader is in communication with a computer  16  of an order management system  14  and the computer is configured to receive information from the RFID reader  18  and determine, based on the received information, if the RFID tag has moved in 3D space relative to either the workstation  12 , the inventory receptacle  20  containing the inventory item (which may include a unique RFID tag affixed to the receptacle), or an RFID tag of another item in the inventory tote  20 . Recognizing  110  a movement of the RFID includes determining with the computer if there has been a change in a positional characteristic of the RFID tag, such as an elevation change, a horizontal translation, or a rotation, for example. The system  10  may recognize that an RFID tag of a particular item in a tote of mixed SKU items has moved a significant or sufficient distance (after its initial arrival at the picking station) to determine that the item has been selected by the operator. For example, the system may recognize that the RFID tag of an item has reached a certain elevation above other items in the inventory tote  20  or has disappeared from or moved out of the envelope of the inventory tote  20 , and thus the system may conclude that the item associated with that RFID tag has been picked. The envelope of the tote  20  may be represented by the tote&#39;s perimeter dimensions and/or the storage volume/capacity of the tote. The verification  108  and recognizing  110  are performed automatically, as directed by the computer  16  and order management system  14 , and thus does not require confirmation from an operator that the correct item has been picked. In instances where multiple items are required from the present inventory receptacle  20 , the method  100  is capable of verifying  108  that each of the correct items have been picked by the operator ( FIGS.  1 A- 1 B and  7   ). The operator is corrected  112  if they have selected a wrong item, such as with haptic feedback via a wearable device worn on the operator&#39;s person, for example, and the operator returns or replaces  114  the item into the inventory tote  20  ( FIGS.  1 A- 1 B and  5   ). 
     If it is verified that the item is accurately selected from the inventory tote  20  at  108 , the method  100  includes assigning  116  an order container or tote  24  at the workstation  12  in which to place the retrieved item into ( FIGS.  1 A- 1 B and  3   ). The operator transfers  118  the selected item into the assigned order container  24 . Similar to the locating step  104 , the method  100  may include directing the operator to the required placement location within the workstation (e.g. an order container  24  or particular portion of the order container or another inventory tote  20 ) with a visual, audible, or physical feedback or cue, such as a laser light, a heads-up display, a spatial sonification device, a wearable device with a haptic feedback function, lighting a representative position on the workstation or outside of the tote to indicate the desired position of the wanted item, or illustrating the desired placement position on a picking station screen, for example. For robotic operators, the computer directs the movement of the robot operator to the placement location for the item. 
     The placement or disposition of the item into the order container  24  is validated  120  by determining or recognizing  122  that the location of the RFID tag is within an envelope of the assigned order container (and possibly to a particular quadrant or location within the container) to confirm that the required item is correctly disposed in the assigned order container  24  ( FIGS.  1 A- 1 B and  3   ). Recognizing or determining  122  that the RFID has moved to within the envelope of the order container (or a more precise position within the container) includes determining with the computer if a positional characteristic of the RFID tag, such as its elevation, horizontal location, or orientation, are within the envelope of the order container. For example, the required accuracy (i.e. tolerance) of the elevation of the item&#39;s RFID tag as compared to the pre-determined or instantaneously determined height of the order container may be pre-defined (e.g. at least 5 millimeters below the upper edge of the container), such that if the RFID tag is determined to be below the height of the order container (i.e. meeting the required tolerance), the item is determined by the computer to have been properly placed in the order container. In instances where the order container  24  includes an RFID tag, the validation  120  may be determined  122  as a function of the proximity of the item&#39;s RFID tag to the RFID tag of the order container. 
     Similar to the incorrect pick and correction scenario of steps  112  and  114 , the operator is corrected  124  if they have placed the item in the incorrect location or order tote  24 , such as with haptic feedback via a wearable device worn on the operator&#39;s person, for example ( FIGS.  1 A- 1 B ). The operator must subsequently remove  126  the item from the incorrect tote and the operator is re-directed at  116  and  118  to transfer the item into the correct order container ( FIGS.  1 A- 1 B ). If it is determined at  122  that the item is correctly placed in the order container  24 , the method determines  128  if the order for the assigned order container requires any additional items or order lines, and if so, the method locates  104  the additional item(s) in the inventory tote and steps  106 - 126  are repeated as necessary until the order is complete. If an order line is completed it is removed  130  from the order database or pick list. Steps  102 - 130  are repeated if necessary to fulfil  132  all order lines on the pick list, and once all order lines are complete the method determines that the order or pick list is completed at  134 . 
     Validating  120  that the required item is disposed in the assigned order container may include determining a location of an RFID tag that is affixed to the assigned order container and comparing the position of the RFID tag of the required item relative to the envelope of the assigned order container. Preferably, the envelope dimensions of the assigned order container are associated with the RFID tag affixed to the assigned order container. However, it will be appreciated that the envelope dimensions may be determined by other acceptable methods, such as by capturing image data of the order container with an image capture device and the computer of the order management system determining the dimensions of the container utilizing the captured image data, for example. The order picking process is improved and made more efficient by accurately verifying whether the correct item has been picked and/or validating whether the picked item has been placed or disposed in the correct location, without requiring an additional operator process step (e.g. scanning the selected item or performing a visual confirmation) to be performed by the operator. 
     The verification system  10 , as mentioned above, is provided for monitoring item level order fulfilment operations at an order fulfilment workstation  12  that is in communication with an order management system  14  ( FIG.  2   ). The verification system  10  includes a computer  16  in communication with the order management system  14  and one or more radio frequency identification (RFID) readers or sensors  18  that are in communication with the computer (e.g. either wired or wireless communication). It will be appreciated that a single RFID reader may be sufficient to perform the desired verification of item level order fulfilment operations within a particular facility. Inventory items within the facility are fitted with RFID tags. While it is preferable that all of the inventory items include an RFID tag, it will be appreciated that this is not a requirement and only some of the inventory items may include RFID tags. The RFID readers or sensors  18  read/recognize RFID tags that are in proximity of the reader (i.e. RFID tags on items that are present at the workstation) and communicate information associated with the RFID tags to the computer  16 . The order management system  14  and computer  16  control the order fulfilment workstation  12  and may direct item level picking operations of an operator at the order fulfilment workstation  12 , either human or robotic operators. The RFID reader  18  is positioned at a remote location relative to the picking area  12   a  of the workstation  12  ( FIG.  2   ). The computer  16  is adapted to determine a location of inventory items&#39; RFID tags relative to either the workstation  12 , a receptacle or inventory tote  20  containing the inventory item, or relative to RFID tags of other inventory items in the inventory tote  20 . The computer  16  verifies  108  that an operator at the workstation  12  has correctly chosen a particular one of a plurality of inventory items that are present at the workstation  12  by recognizing  110  a movement of the RFID tag of the correct inventory item ( FIGS.  1 A- 1 B and  2   ). 
     The verification system  10  includes a pick directing device, such as a wearable in the form of glasses  22  ( FIGS.  3 - 7   ) that provide a laser light or heads-up display, for directing or guiding the operator to the location of a particular inventory item or items at the workstation  12 . The glasses  22  are preferably dynamic such that as the operator moves their head or body, the location indicator automatically adjusts to continue to show the location of the required item. It will be appreciated that other types of pick directing devices may be used to guide or direct the operator, such as a spatial sonification device, a wearable device with a haptic feedback function, a smart lighting system operable for lighting a representative position on the outside of the tote to indicate the relative position of the wanted item inside the tote, or illustrating the position on a picking station screen, for example. Robotic operators may be controlled by the computer to direct their picking operations. 
     The computer  16  may be adapted to direct an operator to place the retrieved item in a particular order container  24  and to validate that the operator has placed the item in the correct order container  24  by determining that the location of the item&#39;s RFID tag is within an envelope of the correct order container  24 . The pick directing device (e.g. glasses  22 , laser light, heads-up display, spatial sonification device, wearable device with a haptic feedback function, smart lighting system, picking station screen, or electronic controller) may be adapted to direct the operator to a particular location where the retrieved item needs to be placed. It will be appreciated that the retrieved item may require placement onto a conveyer  26 , into an order container  24  as described above, or into another inventory tote  20 , whichever is necessary for processing the retrieved item. 
     The verification system  10  may be operable to determine whether the item is placed at a particular portion of the placement location. For example, for an order container  24  having multiple compartments, the RFID reader  18  and computer  16  may be capable of locating the RFID tag of the placed item and determining that it is placed in the correct quadrant or compartment of the order container  24 . The order container  24  may include an RFID tag affixed to one or more portions thereof and the RFID reader  18  can communicate to the computer  16  the position of the RFID tag of the order container  24 . As such, the computer  16  may compare the position of the RFID tag of an item placed in the order container  24  with the position of the RFID tag of the order container  24  to determine if the item has been placed in the correct portion of the order container  24 . Preferably, the envelope (i.e. perimeter dimensions) of the order container  24  is associated with the container&#39;s RFID tag and the computer  16  can access the envelope dimensions with information provided by the RFID reader  18 . It will be appreciated that the system  10  may include image capture devices in communication with the computer  16  to gather image data of an order container  24  present at the workstation  12 . The image capture devices enable the computer  16  to determine the envelope of the present order container  24  and then determine and validate whether the RFID tag of a placed item is within the envelope of the order container  24 . 
     Referring to the illustrative embodiment of  FIG.  8   , an RFID enabled material handling system  200  is provided for an order fulfilment or warehouse facility. The handling system  200  is provided for tracking and monitoring the movement of individual items within the facility. The system  200  includes various or multiple RFID readers or sensors  18  distributed throughout the system  200  and positioned in proximity to various or multiple components of the system  200 , including automated storage and retrieval systems (ASRS)  202 , induction stations or inducts  204 , and along the path of an automated unit sorter, such as in the form of a circular sorter  206  as shown in  FIG.  8   , or any other suitable sortation system. The individual items handled by the system  200  each have an RFID tag affixed thereon. Preferably each individual item includes an RFID tag, however, it will be appreciated that the system  200  is also beneficial when only some of the items have RFID tags. The individual items are routed from an ASRS  202  to a corresponding induct  204  in an inventory tote  20 . An RFID reader  18  at the induct  204  reads any RFID tags of items within the inventory tote  20  and sends that information to a computer  16 . The computer  16  determines which items within the inventory tote  20  are required for an order or for transport to a different portion of the facility. The required items are inducted (i.e. transferred) to the sorter  206  which directs the individual items to the appropriate downstream process (e.g. conveyor, Gaylord, pouch, order container, etc.) via chutes  208 . The RFID readers  18  proximate the path of the sorter  206  read and track the RFID tags of individual items as they traverse the sorter  206  and the readers  18  send the information to the computer  16 . Utilizing the tracked location information of an item&#39;s RFID tag, the computer  16  directs the sorter  206  to divert the individual item to the appropriate chute  208 . The system  200  and method  100  may utilize structural arrangements and functions (such as the sorter, induct, and chute arrangement and control, for example) is similar manner to those disclosed in commonly owned and assigned U.S. Provisional Patent App. Ser. No. 63/312,945, filed Feb. 23, 2022, by Dematic Corp. of Grand Rapids, Mich. and entitled OMNICHANNEL SORTATION SYSTEM, the disclosure of which is hereby incorporated herein by reference in its entirety. 
     The induct  204  may discharge individual items in various manners. For example, an operator (human or robot) at the induct  204  may select only required items from the inventory tote  20  and transfer each required item to the sorter  206 , possibly in a similar manner to how items are located  104  and retrieved  106  for method  100  as described above and illustrated in  FIGS.  1 A- 1 B , for example. As another example, an operator at the induct  204  or an automated mechanical device may dump or otherwise empty the entire contents of the inventory tote  20  onto the induct  204  and the operator may select any required items and forward them to the sorter  206 , which may be performed with the aid of the RFID readers  18  and the computer. In yet another example, the induct  204  may forward all of the dumped items to the sorter  206  and the computer  16 , utilizing information gathered by the RFID readers  18  at the sorter  206 , will direct any required items to appropriate chutes  208 , and any unwanted items may be directed back to a recirculation system to be replaced back into an ASRS  202  for future orders processes. Alternatively, the induct  204  may be omitted or bypassed and the inventory tote  20  may be emptied or dumped directly onto the sorter  206  and the computer  16  and RFID readers  18  cooperate to direct the required items to appropriate chutes  208  and any unwanted items may be directed back to an ASRS  202 . Accordingly, the RFID enabled handling system  200  utilizes RFID readers  18  and RFID tags on individual inventory items to direct the items to appropriate locations and processes within the facility and also verifies and validates that the required items are delivered to their appropriate location. 
     Thus, the verification system and method of the present invention enhance the order picking function within an order fulfilment facility in which multiple different SKUs are stored in a single inventory tote wherein items may not be readily visually distinguishable by the picking operator. The verification system and method provide a verification and feedback system that does not require additional verification steps to be taken by the order picker, and is capable of providing immediate and accurate feedback to an order picker, preferably without the need for the order picker to perform any visual inspection. The verification system may be adapted for use in an RFID enabled material handling system in which individual items with RFID tags are directed through a facility as a function of their locations proximate RFID readers disposed throughout the facility. The verification system is enabled to verify and validate that each individual item has reached its required destination. 
     Changes and modifications in the specifically described embodiments can be carried out without departing from the principles of the present invention which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents.