Patent Publication Number: US-2022234844-A1

Title: Depalletization systems and methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 63/141,775, filed Jan. 26, 2021. The disclosure of the prior application is considered part of (and is incorporated by reference in) the disclosure of this application. 
    
    
     TECHNICAL FIELD 
     This document relates to systems and methods for enhancing warehouse material handling operations. For example, this document relates to automation systems and methods that make depalletization processes more safe and efficient. 
     BACKGROUND 
     Depalletization is a material handling process which simply means transferring containers (e.g., boxes, totes, etc.) from a pallet or other type of shipping container to a conveyor or other material handling means. Depalletization is a common material handling process that is an important aspect of warehouse operations. The efficiency of material handling processes, such as depalletization, at warehouses is an important business issue for retailers. 
     The use of warehouse automation is one way to increase the efficiency of warehouse operations such as depalletization and other aspects of material handling and order fulfillment processes. The goals of warehouse automation include the efficient use of space resources, and the elimination of manual steps of the order fulfillment process such as depalletization, and to optimize the efficiency of material handling and order fulfillment processes. Warehouse automation technology is useful for multiple reasons, such as, to make material handling processes more efficient, to lower overall costs, to improve worker safety by mitigating ergonomic risks, and to help reduce the occurrences of human error. 
     SUMMARY 
     This document describes systems and methods for enhancing warehouse material handling operations. For example, this document describes automation systems and methods that make depalletization processes more safe and efficient. In some examples, the depalletization systems described herein include multiple work cells/stations and a depalletization robot that traverses the work cells/stations on a rail so the robot can autonomously move between the stations. 
     While the depalletization robot works in one of the multiple stations, a worker can move an empty pallet out of another station and/or move a full pallet into the station while the robot continues to work. If there is a jam or some type of problem in one work station, an alarm can be triggered for a worker to come and address the problem while the depalletization robot moves on to depalletize in another work station. In these example ways, the downtime of the depalletization robot is minimized. 
     Also, as described further below, the depalletization systems described herein include safety devices so that human workers are not endangered by the depalletization robot while the workers are also performing work in or around the work cells. For example, in some embodiments there can be automatic doors between the depalletization robot and each work cell. In such as case, the worker would only go into the work cell when the door is closed. In addition, in some embodiments there are light curtains, motion sensors, and/or physical barriers (e.g., fencing) that provide additional safety features. 
     In one aspect, this disclosure is directed to a system for depalletization that includes multiple depalletization workstations. Each of the depalletization workstations is configured to receive a respective pallet or cart of items such as boxes, cartons, totes etc. The depalletization system also includes an output conveyor extending along the multiple workstations. The output conveyor is configured to receive and transport individual items of the pallets of items. 
     The depalletization system also includes a depalletization robot including an end effector. The depalletization robot is configured to travel along the multiple workstations. Accordingly, the pallets of items in each of the workstations is accessible by the end effector of the depalletization robot. 
     The depalletization system also includes a control system in electrical communication with the depalletization robot and other sensors and devices of the depalletization system. 
     Such a depalletization system may optionally include one or more of the following features. For example, in some embodiments the control system is configured to provide an output signal to initiate a movement of the depalletization robot away from a first workstation of the multiple workstations to a second workstation of the multiple workstations in response to receiving a signal that indicates that a first pallet of items in the first workstation is empty of the items. Moreover, in some embodiments the control system is configured to provide an output signal to initiate a movement of the depalletization robot away from a first workstation of the multiple workstations to a second workstation of the multiple workstations in response to receiving a signal that indicates the detection of an issue that inhibits the depalletization robot from further depalletization at the first workstation. Such an issue may require involvement by a worker to resolve the issue, for example. In another example, in some embodiments the control system is configured to provide an output signal to initiate a movement of the depalletization robot away from a first workstation of the multiple workstations to a second workstation of the multiple workstations in response to receiving a signal that indicates that a worker has requested physical access to the first workstation. 
     In some embodiments, the end effector of the depalletization robot is configured to simultaneously releasably couple with multiple items of the pallet of items. In some cases, at least two of the multiple items in a layer of items have differing top surface elevations. The end effector of the depalletization robot can include multiple suction cups configured to simultaneously releasably couple with the multiple items in a layer of items. In some embodiments, the multiple suction cups have individual spring suspensions to facilitate the engagement of the suction cups with the layer of items that have differing top surface elevations. The multiple items to which the end effector of the depalletization robot simultaneously releasably couples with can be an entire layer of the items from the pallet of items. 
     In some embodiments, adjacent workstations of the multiple workstations are separated by a respective partition. Such a partition can be fencing, rails, walls, light curtains, LEXAN/plexiglass, and the like. 
     In some embodiments, the depalletization system includes multiple doors. For example, in some embodiments each workstation of the multiple workstations is separated from the depalletization robot by a respective door of the multiple doors. The opening and closing of each door of the multiple doors can be automatically controlled by the control system of the depalletization system using a scheme that is focused on protecting workers who need to enter the workstations at times. For example, in some embodiments the control system controls a first door of the multiple doors to be open while the depalletization robot is accessing a first workstation of the multiple workstations and all other doors of the multiple doors to be closed while the depalletization robot is accessing the first workstation of the multiple workstations. 
     In some embodiments, the depalletization system includes multiple light curtains. For example, in some embodiments worker access to each workstation of the multiple workstations is via a respective light curtain of the multiple light curtains. In some embodiments, there are respective light curtains between each of the workstations and the positions at which the depalletization robot accesses the respective workstations. In some embodiments, an actuatable physical barrier (e.g., an automated door) is located between each of the workstations and the positions at which the depalletization robot accesses the workstations. 
     In some embodiments, the depalletization system includes a respective vision system associated with each workstation of the multiple workstations. The vision systems are in communication with the control system. For example, in some embodiments the vision systems and control system are configured to determine positions of a highest level of items on the pallet of items in each workstation. In some embodiments, the vision systems and control system are configured to determine the positional coordinates and/or orientations of the levels of the items on the pallet of items in each workstation. 
     In another aspect, this disclosure is directed to a method for depalletization of items from pallets, carts, or any other type of item agglomeration means. The method for depalletization includes actuating, by a control system of a depalletization system, a robot of the depalletization system. The robot of the depalletization system is configured to traverse between multiple depalletization workstations. The actuating by the control system causes the robot to move, for example, from a first depalletization workstation of the multiple depalletization workstations to a second depalletization workstation of the multiple depalletization workstations. The method for depalletization also includes actuating, by the control system, the robot to engage with and remove a top layer of items from a pallet in the second depalletization workstation to thereby expose a second layer of items on the pallet. The method for depalletization also includes actuating, by the control system, the robot to transfer the top layer of items from the pallet to a conveyor. The method for depalletization also includes actuating, by the control system, the robot to engage with the second layer of items from the pallet and to transfer the second layer of items to the conveyor. Such actuations of the robot can continue until the pallet is emptied of items. 
     Such a method of depalletization may optionally include one or more of the following features. In some embodiments, in response to the pallet being emptied of items, the control system actuates the depalletization robot to move from the second depalletization workstation to a different depalletization workstation of the multiple depalletization workstations. The method may also include, after the robot has moved from the second depalletization workstation to the different depalletization workstation, actuating, by the control system, a door to close between the robot and the second depalletization workstation. 
     In some embodiments, the top layer of items on the pallet includes items with top surfaces that are at differing elevations. 
     In some embodiments, in response to an input to the control system, the control system: (i) actuates the robot to move from the second depalletization workstation to a different depalletization workstation of the multiple depalletization workstations and (ii) after the robot has moved from the second depalletization workstation to the different depalletization workstation, actuates a door to close between the robot and the second depalletization workstation. 
     In some embodiments, in response to an input to the control system from a light curtain associated with the second depalletization workstation, the control system causes a stop to all motion of the robot while at least a portion of the robot is within the second depalletization workstation. 
     The systems and processes described here may be used to provide one or more of the following optional benefits. First, the depalletization systems described herein are advantageously designed accommodate “mixed pallets.” Mixed pallets contain two or more different types of SKU items (rather than being all the same type of SKU item). Accordingly, the depalletization systems are flexible and usable with many different types of materials including mixed pallet loads that have multiple different kinds of packaging materials. 
     Second, worker safety enhancements are provided by the systems and processes described herein. The need for manual lifting is reduced. In addition, other manual tasks (such as twisting and reaching while holding the weight of boxes) that workers generally perform for depalletization in accordance with conventional methods are reduced or eliminated. Accordingly, the potential for worker injuries is advantageously reduced. 
     Third, labor costs associated with depalletization processes can be reduced using the automated systems and processes described herein. Productivity is improved. That is, because of automation, fewer human workers are required for the depalletization processes described herein. In addition, the automated systems for depalletization described herein can handle more boxes per hour than conventional methods that are more manual-based. 
     Fourth, some embodiments of the depalletization systems include multiple workstations that provide operational redundancy. That is, if an interruption occurs while depalletization is taking place in one workstation, the robotic system can move on to another workstation while the source of the interruption is resolved. Accordingly, system downtime is minimized by the workstation redundancy. 
     Fifth, in some cases warehouse space requirements can be reduced using the automated systems and processes described herein. 
     Other features, aspects and potential advantages will be apparent from the accompanying description and figures. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  depicts a first example warehouse depalletization system in accordance with some embodiments. 
         FIG. 2  depicts a second example warehouse depalletization system in accordance with some embodiments. 
     
    
    
     Like reference symbols in the various drawings indicate like elements 
     DETAILED DESCRIPTION 
     This document describes systems and methods for enhancing warehouse material handling operations. For example, this document describes automation systems and methods that make depalletization processes more safe and efficient. In some examples, the depalletization processes can largely be performed robotically. In addition, in some embodiments the systems for the depalletization processes can include multiple workstations to enhance the utilization of the depalletization robot, as described further below. 
       FIG. 1  depicts an example warehouse depalletization system  100 . Such a depalletization system  100  can be used beneficially in any number of different types of facilities such as, but not limited to, flow centers, distribution centers, warehouses, inventory storing locations, order fulfillment centers, receive centers, stores, cross-docking facilities, material handling facilities, and the like, and combinations thereof. In this disclosure, the term “warehouse” may be used to refer to any and all such different types of facilities, and combinations thereof. 
     The depalletization system  100  includes, broadly speaking, a depalletization robot  110 , an output conveyor  120 , a control system  130 , and multiple workstations  140   a,    140   b,    140   c,  and  140   d  (or  140   a - d  collectively). Other devices and systems are also included, as described further below. 
     The depicted example depalletization system  100  includes four workstations  140   a - d.  However, in practice, the inventive concepts of the depalletization system  100  can be applied to depalletization operations that have fewer than four or more than four workstations. For example, in some embodiments two workstations or three workstations are included in the depalletization system. In other cases, more than the four workstations  140   a - d  are included, such as five, six, seven, eight, nine, ten, or more than ten workstations. 
     Each workstation can receive and contain a pallet of items, or other type of container of items. For example, in the depicted arrangement, the workstation  140   a  contains a pallet of items  150   a.  The workstation  140   b  includes a cart of items  150   b.  The workstation  140   c  includes a pallet of items  150   c,  and the workstation  140   d  includes a cart of items  150   d.  To keep the description of the depalletization system  100  clear, hereinafter the items in the workstations will be referred to as a “pallet” of items. However, it must be understood that the term “pallet” represents any other type of suitable item agglomeration means such as, but not limited to, carts, bin, totes, bags, cartons, containers, and the like, without limitation. 
     Each pallet of items, such as the pallet of items  150   a  for example, has on it, or is carrying, multiple items. In the depicted example, the pallet of items  150   a  has multiple boxes on it. While boxes are used here as to represent the “items” in the depicted example, it should be understood that the boxes are representative of various other types of items. For example, the items can be reusable containers, totes, bulk packs, shrink-wrapped packages, bags, cartons, and the like, without limitation. 
     Each pallet of items can include multiple items that are all the same (which can also be referred to as a “homogeneous pallet”), or alternatively can include multiple items that are not all the same (which can also be referred to as a “mixed pallet”). The depalletization system  100  can operate with both/either homogeneous pallet and/or mixed pallets, and combinations thereof. For example, the pallet of items  150   a  is a mixed pallet. 
     In general, the items on a pallet are arranged in layers. That is, for example, the pallet of items  150   a  has two layers of items. In another example, the pallet of items  150   c  has four layers of items. The depalletization system  100  described herein can operate with pallets that have any number of layers of items. 
     In some cases, such as the example pallet of items  150   a,  the top surfaces of the items of a layer of items are at differing elevations. Said another way, some layers of items are comprises of two or more items that have upper surfaces that are uneven with each other. For example, the upper left box of the top layer of items on the pallet of items  150   a  has a top surface that is above the top surfaces of the items that are adjacent to it. This unevenness is common in the context of mixed pallets. In contrast, homogeneous pallets will typically not have such unevenness. 
     The depalletization system  100  described herein is operable to depalletize mixed pallets and/or homogeneous pallets. Moreover, the depalletization system  100  described herein is operable to depalletize layers of items that are even and/or uneven. That is, the depalletization system  100  can depalletize layers of items that have differing top surface elevations (such as depicted by the pallet of items  150   a ). 
     The depalletization system  100  includes the depalletization robot  110 . The depalletization robot  110  can traverse along the multiple workstations  140   a - d,  as indicated by the heavy double-ended arrow in  FIG. 1 . For example, in the depicted arrangement the depalletization robot  110  is in alignment to work within the workstation  140   a.  In other arrangements, the depalletization robot  110  can be aligned with any of the other workstations  140   b - d.  The movements of the depalletization robot  110  between the workstations  140   a - d  are initiated and controlled by the control system  130 . 
     In the depicted embodiment, the depalletization robot  110  can traverse along the multiple workstations  140   a - d  along a floor-mounted rail that extends along the multiple workstations  140   a - d  (and, in the depicted example, along the conveyor  120 ). In some embodiments, the depalletization robot  110  can traverse along the multiple workstations  140   a - d  along an overhead rail that extends along the multiple workstations  140   a - d.    
     The depalletization robot  110  is an articulated robot that includes an end effector  112 . While various types of end effectors can be used with the depalletization robot  110 , in the depicted embodiment the end effector  112  include multiple suction cups. The multiple suction cups are configured to releasably couple with the uppermost layer of items from a pallet of items  150   a - d.    
     In some embodiments, the multiple suction cups of the end effector  112  are configured to couple with a layer of items that have top surfaces at differing elevations (such as depicted by the pallet of items  150   a ). For example, in some embodiments the multiple suction cups of the end effector  112  include spring suspensions. That is, in some embodiments certain suction cups, or groups of suction cups, have suspension mechanisms that allow those suction cups to vertically adjust to the elevation of the top surface of the items. Accordingly, the spring suspensions of the multiple suction cups of the end effector  112  enable the end effector  112  releasably couple with a layer of items that have top surfaces at differing elevations (such as depicted by the pallet of items  150   a ). 
     The depalletization system  100  also includes the control system  130 . The control system  130  can include one or more programmable computer processors with accessible memory, and/or can include portions that use simply relay logic in some embodiments. The control system  130  can broadly include and encompass multiple components such as, but not limited to, programmable logic controllers (PLC), relays, motor drives, sensors, and various other input and output devices for interacting with and controlling the depalletization robot  110  and other aspects of the depalletization system  100 . 
     The control system  130  can be realized in digital electronic circuitry, integrated circuitry, specially designed ASICs (application specific integrated circuits), computer hardware, firmware, software, and/or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device. 
     The computer programs of the control system  130  (also known as programs, software, software applications or code) can include machine instructions for a programmable processor, and can be implemented in a high-level procedural and/or object-oriented programming language, and/or in assembly/machine language. 
     In some embodiments, the control system  130  includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the control system  130  can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), and the Internet. 
     To provide for interaction with a user, control system  130  can be implemented on a computer having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse, a trackball, or a touchscreen, etc.) by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, tactile input, eye movement tracking input, a brain-computer interface, gesture input, and the like, and combinations thereof). 
     The control system  130  can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. 
     The control system  130  receives input signals, processes the input signals in accordance with programmed logic, and emits output signals to control movements of the depalletization robot  110  and other systems/devices of the depalletization system  100 . 
     The depalletization system  100  also includes the output conveyor  120 . The output conveyor  120  receives the items that the depalletization robot  110  picks up and transfers to the output conveyor  120 . The output conveyor  120  can be any type of conveyor including but not limited to, a belt conveyor, a roller conveyor, a link conveyor, and the like, and combinations thereof. The output conveyor  120  transfers the items away from the depalletization system  100  to a subsequent downstream warehouse process, to a retail store, and the like, without limitation. In some embodiments, the output conveyor  120  includes devices for singulation of the items. That is, because some separation between items on the output conveyor  120  may be desirable (e.g., for barcode scanning of the items), a singulation device can be included to facilitate such separation of items. 
     The output conveyor  120  extends along the workstations  140   b - d.  In the depicted embodiment, the output conveyor  120  is positioned between the workstations  140   b - d  and the depalletization robot  110 . Accordingly, the motions of the depalletization robot  110  are minimal when the depalletization robot  110  transfers the items from the pallets  150   a - d  to the output conveyor  120 . This arrangement also enables the depalletization system  100  to operate at a high rate of depalletization efficiency. 
     Other features, systems and devices can be optionally included in some embodiments of the depalletization system  100 . For example, in some embodiments the depalletization system  100  includes one or more vision systems  160 . The one or more vision systems  160  can be comprised of one or more video cameras (e.g., one or more cameras used in conjunction with image-analysis software), 3D vision recognition systems, lasers, ultrasonic sensors, and the like, and combinations thereof 
     Some embodiments of the depalletization system  100  include an individual dedicated vision system  160  for each workstation of the workstations  140   a - d.  Alternatively, in some embodiments of the depalletization system  100  a single vision system  160  can be used for two or more (or all) of the workstations of the workstations  140   a - d.  In some embodiments, the one or more vision systems  160  overhang the workstations  140   a - d  from above. 
     The one or more vision systems  160 , in conjunction with the control system  130 , can perform various functions. For example, in some embodiments the one or more vision systems  160  can facilitate a determination of the elevation of the top surfaces of the uppermost layer of the items on the pallets  150   a - d.  That determined elevation can then be used by the control system  130  to actuate depalletization robot  110  appropriately to couple with the uppermost layer of the items on the pallets  150   a - d.  In some embodiments, the vision systems  160  and control system  130  are configured to determine the positional coordinates and/or orientations of the items on the pallets  150   a - d  in each workstation. 
     In yet another example, the one or more vision systems  160 , in conjunction with the control system  130 , can facilitate a determination of whether the items on the pallets  150   a - d  have been completely removed. When the items on a pallet of the pallets  150   a - d  have been completely removed, then the control system  130  can actuate the depalletization robot  110  appropriately to move on to working on another pallet of the pallets  150   a - d  that has items on it. 
     In still another example, the one or more vision systems  160 , in conjunction with the control system  130 , can facilitate a determination of the position and the orientation of the pallets  150   a - d  within the workstations  140   a - d.  For example, workers typically move the pallets  150   a - d  into the workstations  140   a - d  using a pallet jack (or on wheels as in the case of a cart, e.g., see pallet  150   b  in workstation  140   b ). Accordingly, the physical placement of the pallets  150   a - d  within the workstations  140   a - d  will be at least slightly different from situation to situation (pallet to pallet). The one or more vision systems  160 , in conjunction with the control system  130 , can determine the actual position and the orientation (or coordinates) of the pallets  150   a - d  within the workstations  140   a - d  and then the control system  130  can actuate the depalletization robot  110  appropriately to accurately couple with the items that are on the pallets  150   a - d.  In some embodiments, the one or more vision systems  160 , in conjunction with the control system  130 , can determine the actual position and the orientation (or coordinates) of the layers of the items on a pallet of the pallets  150   a - d  (e.g., even if the layer of the items is a partial layer, including a single item). 
     In some embodiments, the workstations  140   a - d  are separated by partitions. The partitions can be various types of partitions including, but not limited to, fencing, rails, or walls. 
     In some embodiments, the workstations  140   a - d  include safety features such as light curtains and/or other types of sensors that are in communication with the control system  130 . For example, a respective light curtain can be located at the entrance to each of the workstations  140   a - d.  If the depalletization robot  110  is operating in a particular workstation and the light curtain of that particular workstation is “broken” (e.g., the light curtain senses that a person has moved at least somewhat into the particular workstation), then the control system  130  can immediately stop the movements of the depalletization robot  110  for safety sake. 
     In another example, when a light curtain senses that a worker is working in a particular workstation (e.g., moving a pallet into or out of a particular workstation), when the depalletization robot  110  completes its depalletization process in another workstation, then the control system  130  can refrain moving the depalletization robot  110  to the workstation in which the worker is working. In some embodiments, one or more other types of sensors can be used such as, but not limited to, motion sensors, ultrasonic sensors, optical sensors, and the like, and combinations thereof. 
     In some embodiments, one or more switch devices can be located near the entrance to each of the workstations  140   a - d.  Such switch devices can be in communication with the control system  130  and can be used by workers when there is a need to enter a workstation of the workstations  140   a - d.  For example, by activating such a switch device prior to entering a particular workstation, the control system  130  will prevent the depalletization robot  110  from entering the particular workstation. Or, if the depalletization robot  110  is in the particular workstation, the control system  130  can cause the depalletization robot  110  to immediately stop all motion (“freeze”) in response to the activation of the switch device. After the worker is done with physically being within the particular workstation, the worker can reset the switch device to indicate to the control system  130  that the depalletization robot  110  can enter the particular workstation as necessary. 
     In some cases during a depalletization process, the depalletization robot  110  and/or control system  130  may encounter a problem that requires a worker&#39;s intervention. This can be termed an “alarm condition.” In such a case, a notification regarding the alarm condition can be provided to a worker. The alarm condition notification can be of various modalities such as, illumination of a light, an audible alarm, a SMS message, and the like, and combinations thereof. In the meantime while waiting for the resolution of the problem, the depalletization robot  110  can move on to performing depalletization in another workstation. In response to the alarm condition notification, the worker can report to the workstation that has the problem, resolve the problem, and reset the alarm condition. Thereafter, the depalletization robot  110  can return to the workstation that had the problem and continue the depalletization process. 
       FIG. 2  depicts another example depalletization system  200 . The depalletization system  200  is a variation of the depalletization system  100  described above. The depalletization system  200  includes many of the same systems that the depalletization system  100  includes. Those same systems are identified by the same reference numbers (e.g., the depalletization robot  110  with the end effector  112 , the output conveyor  120 , the control system  130 , the workstations  140   a - d,  the vision system  160 , etc.). 
     The depalletization system  200  also includes doors  142   a  (not visible),  142   b,    142   c,  and  142   d  (collectively “doors  142   a - d ”). In the depicted embodiment, each of the workstations  140   a - d  has a respective door  142   a - d.  The doors  142   a - d  are located between the depalletization robot  110  and the respective workstations  140   a - d.    
     The doors  142   a - d  are actuatable by the control system  130 . That is, the control system  130  can send signals to open and/or close each of the doors  142   a - d  individually. In  FIG. 2 , door  142   a  is open, while the other doors  142   b - d  are closed. 
     Door  142   a  is open in the depicted arrangement of the depalletization system  200  because the depalletization robot  110  is actively performing depalletization in the workstation  140   a.  That is, the depalletization robot  110  is actively in the process of moving items from the pallet  150   a  to the output conveyor  120 . 
     The doors  142   b - d  are closed in the depicted arrangement of the depalletization system  200  because the depalletization robot  110  is not currently active in any of the workstations  140   b - d.  For the depalletization robot  110  to begin working in any workstation of the workstations  140   b - d,  the respective door of the doors  142   b - d  would first have to be opened (e.g., by actuation from the control system  130 ). 
     The doors  142   a - d  serve as a worker safety system. That is, when any one of the doors  142   a - d  is closed, that provides an indication that the respective workstation(s)  140   a - d  is not going to accessed by the depalletization robot  110  (as long as the door is closed). Accordingly, a worker  10  can be within the workstation(s)  140   a - d  that have a closed door, as depicted by the worker  10  in the workstation  140   b  for example. 
     Moreover, since, as described above, the control system  130  can sense when a worker  10  is within a particular one of the workstations  140   a - d,  the control system  130  can keep the respective door of the particular workstation closed as long as the worker  10  is in the particular workstation. This serves to protect the safety of the workers  10  that are within any of the workstations  140   a - d.    
     In some cases, when a worker  10  is within a particular one of the workstations  140   a - d,  the control system  130  can stage the depalletization robot  110  in a position where it is ready to work within the particular one of the workstations  140   a - d  when the worker  10  exits the particular one of the workstations. However, the control system  130  will not allow the depalletization robot  110  to begin working in the particular on of the workstations  140   a - d  until the worker  10  has left. 
     In some embodiments, the doors  142   a - d  are roll-up doors. Alternatively, in some embodiments the doors  142   a - d  are another style of door such as, but not limited to, a bi-fold door(s), a sliding door(s), and the like, without limitation. 
     In some embodiments, the depalletization systems  100 / 200  described herein are configured to allow a worker  10  to manually depalletize from a pallet within a particular one of the workstation  140   a - d  while the depalletization robot  110  is operating in another one of the workstation  140   a - d.  That is, the worker  10  can move items from the pallet within the particular one of the workstation  140   a - d  to the output conveyor  120 , while at the same time the depalletization robot  110  is moving items from the pallet in another one of the workstation  140   a - d  to the output conveyor  120 . Safety systems are utilized to ensure the safety of the worker  10  from the potential of harms from the depalletization robot  110  in such a scenario. For example, in some embodiments light curtains can be employed between the workstations  140   a - d  that will cause the depalletization robot  110  to immediately stop when tripped. In addition, in some embodiments controls that can be activated by the worker  10  can be included to request the opening a particular one of the safety doors  142   a - d  for a workstation when the worker  10  is going to manually depalletize within that workstation. Again, in such a scenario the depalletization robot  110  will be controlled/restrained from potentially harming the worker  10  even while the particular one of the safety doors  142   a - d  is open. 
     Particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. For example, the actions recited in the claims can be performed in a different order and still achieve desirable results. As one example, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous. 
     While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described herein as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. 
     Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system modules and components in the embodiments described herein should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single product or packaged into multiple products.