Motor vehicles for use in inventory control systems

Abstract

A vehicle for use in an inventory management system having multiple destination areas and a guidance system includes a platform for receiving items from a destination area and storing items to be transferred to the destination area, multiple motors, a first drive system, a second drive system, a loading / unloading mechanism, and a clutch mechanism. A drive member of the first drive system is rotated by a first subset of the multiple motors to move the vehicle vertically. A drive member of the second drive system is rotated by a second subset of two or more motors to move the vehicle horizontally. The loading / unloading mechanism is configured to at least one of transfer items to the destination area and retrieve items from the destination area. The clutch mechanism is configured to engage and disengage the loading / unloading mechanism with and from the second subset such that the second drive system drives movement of the vehicle independently of the loading / unloading mechanism.

Description

[Technical Field]

[0001] The present invention relates generally to automated guided vehicles that perform inventory control tasks in a warehouse, storage and / or logistics environment. [Background technology]

[0002] Modern material handling systems, such as those in mail order warehouses, inventory distribution centers, custom order manufacturing facilities, etc., face significant challenges in meeting demand for inventory items. Generally, in the early stages, a company will invest in a level of automation that is at least sufficient for its current needs. However, as the size of an inventory control system increases to accommodate larger quantities and a wider variety of items, the cost and complexity of operating the inventory control system also increases in order to synchronize and complete the packing, storing, replenishing, and other inventory control tasks intended.

[0003] Failure to efficiently utilize resources such as inventory management facility space, equipment, and manpower results in slow throughput, long response times, and a growing backlog of uncompleted tasks. In many cases, temporary efficiency gains can be achieved by gradually expanding the capacity of a facility's existing automation facilities, provided that the expansion is in line with development plans. But sooner or later, you hit a point of diminishing returns. That is, achieving further increases in capacity and / or functionality, even if such increases are fully realized, will ultimately come at a high cost compared to available alternatives. When this point of diminishing returns is reached, facility operators may be forced to abandon their existing material handling facilities and replace them with entirely new automated platforms. Summary of the Invention [Means for solving the problem]

[0004] In accordance with the present invention, the disadvantages and challenges associated with conventional warehouse automation approaches are substantially reduced or eliminated by automated guided vehicles that are configurable to perform a variety of tasks related to inventory control operations. Each automated guided vehicle is configured and operable to perform a first set of inventory control tasks in a first operational mode and to synergistically interact with any of a plurality of functional accessory modules to enable the automated guided vehicle to perform inventory control tasks in further operational modes. Examples of tasks that each automated guided vehicle vehicle is configured to perform using its on-board resources include operating a transfer mechanism of the automated guided vehicle to retrieve inventory items from destination areas in the vertical array of storage areas and / or retrieve inventory items from destination areas in the vertical array of storage areas. For such tasks, each automated guided vehicle is configured to travel vertically along a guidance system that directs the automated guided vehicles to the appropriate destination area, and also horizontally on a generally planar surface extending, for example, between the array of storage areas and a spaced apart location, for example, a picking station, a packing station, or a second vertical array of storage areas.

[0005] The functional attachment modules are sized and configured for easy vertical and horizontal movement by an automated guided vehicle. The separate groups of functionally attached modules are configured and operative to perform distinct sets of inventory control tasks such that the automated guided vehicle maintains its usefulness in the inventory control system even as the system grows in complexity and is required to accommodate new tasks. This functionally attached module approach allows different and / or additional inventory management tasks to be performed simply by substituting and / or adding new types of functionally attached modules capable of performing those additional tasks. In this way, challenges such as inventory segmentation (eg, larger SKU counts), exponentially increasing order picking volumes, and higher throughput can be handled simply, easily, and scalably.

[0006] An automated vehicle for performing inventory control tasks includes a vehicle configured to perform inventory control tasks in an inventory control system having a plurality of destination areas and a guidance system, the vehicle including a platform sized and configured to accommodate an item to be either transferred to or received from one of the destination areas, a plurality of motors, and a first drive member configured to engage the guidance system to move the vehicle along a vertical path segment extending between an underlying support surface underlying the vehicle and one of the destination areas upon operation of a first subset of the plurality of motors. a second drive system having a second drive member configured to engage the lower support surface and drive non-vertical movement of the vehicle through operation of a second subset of the plurality of motors; a loading and unloading mechanism configured to either transfer items from the platform to one of a plurality of destination areas or retrieve items from one of a plurality of destination areas; and a clutch mechanism configured to engage and disengage the loading and unloading mechanism with and from the second subset of the plurality of motors so that the second drive system drives movement of the vehicle independently of the loading and unloading mechanism.

[0007] And, a first subset of the plurality of motors includes a single motor configured to rotate a first drive member of a first drive system. Also, a second subset of motors includes a plurality of motors, a first motor of the second subset driving the rotation of a first drive member of the second drive system, and a second motor of the second subset driving the rotation of a second drive member of the second drive system.

[0008] A first drive member of the first drive system includes a plurality of gears sized and configured to interact with complementary teeth of the guide system to control the position of the vehicle along said guide system. The first drive system may include a pair of drive shafts with driven gears fixed to the drive shafts such that the driven gears are driven synchronously to drive the vehicle along the guidance system.

[0009] A second drive system includes a first drive member driven by a first motor of the second subset to rotate about a first axis of rotation and a second drive member driven by a second motor of the second subset to rotate about a second axis of rotation, the first drive member and the second drive member each being sized and configured to engage a respective portion of the lower support surface for movement of the vehicle over the lower support surface. The clutch mechanism includes: a first rotatable carrier movable between a first angular orientation with the platform and a second angular orientation with the platform, the first drive member being rotatably connected to the first rotatable carrier for angular movement therewith; and a second rotatable carrier movable between the first angular orientation and a second angular orientation, the second drive member being rotatably connected to the second rotatable carrier for angular movement therewith. The first and second rotation axes are coaxial, while the first and second rotatable carriages have a common angular orientation.

[0010] Optionally, the second drive system further includes a first driven member rotatably coupled to the first rotatable carrier and a first endless loop member that transmits rotational power to the first driven member, a second driven member rotatably coupled to the second rotatable carrier and a second endless loop member that transmits rotational power to the second driven member. Each of the first endless loop member and the second endless loop member may include a belt. and a second drive system further comprising a first pulley, the first pulley and first drive member being driven by a first motor of the second subset, the first pulley being sized and configured to engage with the first endless loop member to drive the first drive member; and a second pulley, the second pulley and second drive member being driven by a second motor of the second subset, the second pulley being sized and configured to engage with the second endless loop member to drive the second drive member.

[0011] The clutch mechanism may further include a third driven member rotatably coupled to the first driven member and coaxial with the first driven member, the third driven member being sized and configured to transmit power from the first motor of the second subset by drivingly engaging with the first part of the transfer mechanism while the first rotatable carrier is in the first angular orientation, and a fourth driven member rotatably coupled to the second driven member and coaxial with the second driven member, the fourth driven member being sized and configured to transmit power from the second motor of the second subset by drivingly engaging with the second part of the transfer mechanism while the second rotatable carrier is in the first angular orientation.

[0012] The second drive system further includes a plurality of omnidirectional wheels sized and configured to frictionally engage respective portions of the substrate surface to support the vehicle. And, the second drive system further includes a plurality of drive shafts, and at least one pair of the omni-directional wheels is driven by at least one motor of a second subset of the plurality of motors.

[0013] The automated guided vehicle may further include an on-board control device for controlling the operation of the plurality of motors, the control device including a processing device and a memory containing instructions executable by the processing device for operating the second subset of motors to drive the first drive member and the second drive member of the second drive system to move the vehicle along a substantially horizontal path on the lower support surface. and the memory includes instructions executable by the processor to operate a second subset of the plurality of motors to align each portion of the drive system opposite its corresponding portion of the guidance system and / or to raise or lower the vehicle relative to the datum plane by initiating driving engagement between each portion of the first drive system and its corresponding aligned portion of the guidance system.

[0014] The clutch mechanism may also be configured to enable power transfer from the second subset of motors to the loading mechanism in response to lifting of the vehicle to a position above the datum plane. To this end, the memory further includes instructions executable by the processing unit to operate the second subset of motors such that the loading and unloading mechanism either transfers items from the platform to a destination area adjacent to the vehicle or retrieves items from the destination area to the platform. And, a clutch mechanism is sized and configured to disable operation of the loading and unloading mechanism in response to lowering of the vehicle to a position below the datum plane.

[0015] Another embodiment of a vehicle operable in an inventory management system having multiple destination areas and a guidance system comprises: a first motor drive system configured to engage with the guidance system to move the vehicle along a vertical path segment; a second motor drive system sized and configured to maneuver the vehicle on a surface while the first motor drive system is not engaged with the guidance system; a clutch mechanism configured to engage and disengage the loading and unloading mechanism with a second subset of motors so that the second drive system drives movement of the vehicle independently of the loading and unloading mechanism; and a loading and unloading mechanism operable to transfer items between the vehicle and the multiple destination areas, wherein the first motor drive system includes first and second pairs of rotating members driven by the motors, each pair of rotating members configured to interact with the guidance system to control the position of the vehicle along the guidance system.

[0016] Each rotating member of the first pair of rotating members and the second pair of rotating members may be a gear having teeth sized and configured to engage complementary teeth of the guidance system as the vehicle changes elevation along the guidance system. The first drive system further includes a pair of synchronous drive shafts, with the driven gears fixed to the shafts such that the gears are synchronously driven to drive the vehicle along the guidance system. Optionally, a clutch mechanism is sized and configured to disengage from the loading mechanism when the vehicle descends beyond the datum plane, thereby disabling actuation of the loading mechanism by the controller. Additionally, a clutch mechanism may be sized and configured to engage the loading mechanism when the vehicle is raised above the datum plane, thereby enabling actuation of the loading mechanism by the controller.

[0017] According to a further embodiment, a vehicle operable in an inventory management system includes: a first motor and a second motor; a first pair of omni-directional rollers and a second pair of omni-directional rollers driven by the first motor or the second motor, where the first omni-directional roller of each pair is sized and configured to rotate about a first axis of rotation and the second omni-directional roller of each pair is driven about a second axis of rotation; a fifth roller driven by the first motor or the second motor; and an actuator having an actuating surface configured to move from a first position to a second position to selectively urge the fifth roller toward a lower support surface, wherein the surfaces of each of the first and second pairs of omni-directional rollers and the surface of the fifth roller are sized and configured to contact the lower support surface while the actuator is maintained in the first position, and movement of the actuator to the second position transfers a load from one or more of the omni-directional rollers to the fifth roller.

[0018] One pair of motor-driven omni-directional rollers is driven independently of the second pair of motor-driven omni-directional rollers.

[0019] The actuator is a first actuator, and the automated guided vehicle further includes a sixth roller and a second actuator movable from a third position to a fourth position, and the first actuator and the second actuator move to the second position and the fourth position, respectively, thereby transferring the load from the omnidirectional roller to the fifth roller and the sixth roller.

[0020] The automated guided vehicle further includes a platform and a loading mechanism operable to either transfer an item from the platform to a target surface or retrieve an item from the target surface. The automated guided vehicle may further include a clutch mechanism operable to engage and disengage the loading and unloading mechanism.

[0021] Further embodiments of the present invention will now be described.

[0022] The same reference numbers are used to indicate the same elements common to the figures. The figures are not drawn to scale and are simplified for clarity. Features in one embodiment may be incorporated into other embodiments. [Brief explanation of the drawings]

[0023] A detailed description of the invention may refer to the drawings. However, the drawings only illustrate embodiments of the present invention and do not limit its scope.

[0024] [Figure 1A] FIG. 1 is a perspective view of an inventory management system including a plurality of automated guided vehicles, each configured to interact with functional attachment modules to assist in a parts picking process and perform a subset of inventory management tasks. [Figure 1B] 1 is a perspective view of an inventory control system including a plurality of automated guided vehicles, each configured to interact with a function associated module of a first group of function associated modules to perform a first subset of inventory control tasks and to interact with a function associated module of a second group of function associated modules to perform a second subset of inventory control tasks. [Figure 1C] 1 is a perspective view of an inventory control system including a plurality of automated guided vehicles, each configured to interact with a first group, a second group, or a third group of functionally associated modules to perform a first subset, a second subset, and / or a third subset of inventory control tasks. [Figure 2A] FIG. 2 is a perspective view showing an automated guided vehicle used in any of the inventory management systems shown in FIGS. 1A to 1C. [Figure 2B] FIG. 2B is a plan view of the automated guided vehicle shown in FIG. 2A. [Figure 2C] 2B is a bottom view of the automated guided vehicle shown in FIG. 2A. [Figure 2D] FIG. 2B is a front view of the automated guided vehicle shown in FIG. 2A. [Figure 2E] FIG. 2B is a rear view of the automated guided vehicle shown in FIG. 2A. [Figure 2F] FIG. 2B is a side view of the automated guided vehicle shown in FIG. 2A. [Figure 2G] 1 is a plan view of an automated guided vehicle in the process of retrieving a container of inventory items from a storage area of a plurality of storage areas arranged in vertical rows. [Figure 2H] FIG. 2H is a partial side view taken along line II-H in FIG. 2G, showing the operation of the transfer mechanism. [Figure 2I] 2H is an enlarged side view of a portion of FIG. 2H showing in greater detail the transfer mechanism for transferring items to / from the storage area. [Figure 3A] 2A is a cross-sectional view of the automated guided vehicle of FIGS. 2A to 2F taken along line IIIA-IIIA in FIG. 2A. [Figure 3B] 2A-2F with the clutch mechanism partially disassembled to expose the internal components. FIG. [Figure 4A] 2A is a cross-sectional side view of the automated guided vehicle of FIGS. 2A to 2F taken along line IVA-IVA of FIG. 2A. [Figure 4B] 4B is a cross-sectional side view of the automated guided vehicle of FIGS. 2A-2F taken along line IVB-IVB of FIG. 2A, with the clutch mechanism disengaged. [Figure 4C] 4B is a side view of the automated guided vehicle of FIGS. 2A-2F taken along line IVB-IVB of FIG. 2A, with the clutch mechanism engaged. [Figure 4D] 4D is a side view of the automated guided vehicle of FIGS. 2A-2F with the lateral exterior cover plates omitted to reveal an optional actuator mechanism having a powered member selectively movable between a first position (FIG. 4D) and a second position (FIG. 4E). [Figure 4E] 4D is a side view of the automated guided vehicle of FIGS. 2A-2F with the lateral exterior cover plates omitted to reveal an optional actuator mechanism having a powered member selectively movable between a first position (FIG. 4D) and a second position (FIG. 4E). [Figure 4F] FIG. 4F is an enlarged view of the force applying member of the actuator mechanism shown in FIGS. 4D and 4E in a first, non-force applying position. [Figure 4G] FIG. 4F is an enlarged view of the force applying member of the actuator mechanism shown in FIGS. 4D to 4F in a second force applying position. [Figure 5A] 1 is a front view illustrating the use of an automated guided vehicle with a first group of functional attachment modules in one or more embodiments. FIG. [Figure 5B] FIG. 1 is a perspective view showing pre-docking alignment of an automated guided vehicle, where the first base may be implemented as an integral part of the functional attachment module, as one of the functional attachment modules shown in FIGS. 1A-1C and 5A, or as a separate functional attachment module that serves as an adapter between the vehicle and these other types of functional attachment modules. [Figure 5C] FIG. 1 is a perspective view showing post-merge alignment of an automated guided vehicle; an alternative second base may be implemented as an integral part of the functional attachment module, as one of the functional attachment modules shown in FIGS. 1A-1C and 5A, or as a separate functional attachment module that serves as an adapter between the vehicle and these other types of functional modules. [Figure 5D] FIG. 5C is a rear view of an automated guided vehicle coupled to the base shown in FIG. 5D, with the base and vehicle faces each contacting an underlying support surface at multiple points. [Figure 5E] FIG. 5D is a rear view of the docked automated guided vehicle after the first drive system of the vehicle has been activated to lift the docked base so that none of the surfaces of the base contact the underlying support surface. [Figure 6A]This is a perspective view showing the post-merge alignment of the automated guided vehicle, and the third base may be implemented as an integral part of the functional attachment module, as the functional attachment module shown in Figures 1A-1C and 5A, or as a separate functional attachment module that serves as an adapter between the vehicle and these other types of functional attachment modules. [Figure 6B] FIG. 6B is a rear view of the docked automated guided vehicle of FIG. 6A after the first drive system of the vehicle has been activated to lift the docked base so that none of the surfaces of the base contact the underlying support surface. [Figure 6C] FIG. 6C is a perspective view of an inventory control system illustrating the placement and use of the function attachment modules shown in FIGS. 5A-6B. [Figure 7A] FIG. 1C is a perspective view showing pre-merge alignment of an automated guided vehicle, with a first functional accessory module sized and configured to act as an adapter between the vehicle and other types of functional accessory modules shown in FIGS. 1A-1C. [Figure 7B] 7B is a perspective view illustrating post-merge alignment between the semi-autonomous automated guided vehicle and the first functional attachment module of FIG. 7A. FIG. [Figure 7C] 7C is a rear view of the combined automated guided vehicle and first functionally attached module of FIG. 7B, with the faces of the vehicle and first functionally attached module contacting an underlying support surface at multiple points. [Figure 7D] 7B is a rear view of the combined automated guided vehicle and first functional attachment module of FIG. 7B after the vehicle's first drive system has been activated to lift the first functional attachment module so that none of its faces contact the underlying support surface. [Figure 8A] 7D is a partial front view showing the pre-merge alignment of the docking semi-automated guided vehicle and the first functional accessory module of FIG. 7D, including a second functional accessory module, the second functional accessory module being implemented as a multi-level storage rack having a surface sized and configured to support the storage rack on an underlying support surface. [Figure 8B]A partial front view showing the docking automated guided vehicle and post-docking alignment of the first functional attachment module of Figures 7D and 8A, including the second functional attachment module, after the vehicle's first drive system has been activated to further lift the first functional attachment module and also lift the second functional attachment module so that neither the surface of the first functional attachment module nor the second functional attachment module contacts the lower support surface. [Figure 8C] FIG. 8C is an overall front view showing the relative positions of the combined automated guided vehicle, first function attached module, and second function attached module after the second function attached module has been lifted as shown in FIG. 8B. [Figure 9] A partial perspective view showing elements of an inventory control system including respective groups of first and second functionally attached modules configured to cooperate with an automated guided vehicle to perform a corresponding subset of inventory control tasks, and also a group of third functionally attached modules configured to cooperate with an automated guided vehicle to perform a further subset of inventory control tasks. [Figure 10A] FIG. 10 is a front view illustrating alignment during docking between the automated guided vehicle and one of the third group of functional attachment modules, prior to activation of the first drive system of the automated guided vehicle. [Figure 10B] FIG. 10 is a front view showing the alignment during docking between the automated guided vehicle and the third group of functional attachment modules before activation of the first drive system of the automated guided vehicle. [Figure 10C] 10B is an enlarged partial front view taken from the perspective of FIG. 10A, showing the rotating member of the first drive system aligned opposite its corresponding part of the guide system of the function attachment module of the third group of function attachment modules. [Figure 10D] An enlarged partial front view taken from the same perspective as Figures 10A and 10C, after each rotating member of the vehicle's first drive system has been actuated in a first direction to lift it, along with its corresponding opposing portion of the functional accessory module's guide system. [Figure 10E]Figure 10E is a front view from the same perspective as Figure 10B, after the rotating member of the first drive system has been actuated in a first direction to lift it, along with its corresponding opposing part of the guide system of the functional accessory module. [Figure 10F] This is a front view taken from the same perspective as Figures 10B and 10E, showing each rotating member of the vehicle's first drive system, together with its corresponding opposing portion of the functional attachment module's guide system, after the functional attachment module has been set on a lower support surface as shown, and then actuated in a second direction to raise the vehicle within the functional attachment module. [Figure 11A] FIG. 10B is a rear perspective view showing the arrangement of functional attachment modules, such as those shown in FIGS. 10A-10F, in which the flow rack structure is sized and configured to supply items, such as high turnover merchandise, in a goods-to-picker inventory management system. [Figure 11B] 11B is a side view of the functional accessory module of FIG. 11A just before it is docked with the flow rack structure. [Figure 11C] 11A and 11B, after the functional attachment module has mated with the flow rack structure and raised the vehicle in the functional attachment module to a position for transferring items from the vehicle to the target surface of the flow rack. [Figure 11D] 11A-11C, showing the vehicle in the function attachment module being raised to the position shown in FIG. 11C. FIG. [Figure 11E] 11A-11D, showing the vehicle in the function attachment module being raised to the position shown in FIGS. 11C and 11D. FIG. [Figure 11F] 11A-11E during the transfer of a container from the plane of the flow rack structure of FIG. 11E to an elevated vehicle platform as part of dynamic inventory repositioning. [Figure 11G]11A-11F are plan views illustrating the transfer of items from one vehicle to another using functional attachment modules as part of dynamic inventory placement. [Figure 11H] FIG. 10 is a rear view illustrating the completion of an inventory management task with dynamic inventory placement by the vehicle and functional accessory modules. [Figure 11I] FIG. 10 is a rear view showing the lifting of the vehicle within the function attachment module into a position to transfer items after the function attachment module has docked with the flow rack. [Figure 12] FIG. 1D is a partial perspective view of a portion of an inventory control system that may form part of the inventory control system shown in FIG. 1C and that uses automated guided vehicles to transport containers of inventory items back and forth between a picking area and a plurality of storage locations. [Figure 13A] 13 is a front view of a plurality of automated guided vehicles operated to perform item replenishment and / or item retrieval tasks as part of the inventory management system of FIG. 12. [Figure 13B] 13 is a side view of a plurality of automated guided vehicles operated to perform item replenishment and / or item retrieval tasks as part of the inventory management system of FIG. 12. [Figure 13C] 13 is a plan view illustrating a plurality of automated guided vehicles operated to perform item replenishment and / or item retrieval tasks as part of the inventory management system of FIG. 12. [Figure 13D] FIG. 13C is an enlarged side view of the structure of FIG. 13B showing the vertical support and guidance system. [Figure 13E] FIG. 10 is an enlarged front view of a section of a guide system for use in a rack structure. [Figure 14A] FIG. 1 is a block schematic diagram illustrating allocation of functional accessory module-assisted inventory management tasks among multiple vehicles by a controller. [Figure 14B] FIG. 2 is a block diagram illustrating subsystems of multiple guide vehicles. [Figure 14C]FIG. 1 is a block schematic diagram of a controller that coordinates the allocation and execution of inventory control task activities by multiple vehicle and functional accessory modules. [Figure 15] FIG. 10 is a flow diagram illustrating a process for assigning inventory management tasks to vehicle and functional accessory modules. [Figure 16] FIG. 1 is a flow diagram illustrating a process by which inventory items can be dynamically allocated among various storage areas over a series of consecutive inventory intervals. [Figure 17] FIG. 1 is a flow diagram illustrating a process in which a first operating mode causes an automated guided vehicle to perform inventory management tasks using only the vehicle's onboard capabilities, and a second operating mode causes the automated guided vehicle to supplement its onboard capabilities using additional capabilities of a functional accessory module.

[0025] In this specification, the inventory management system and method for performing each subset of inventory management tasks using functional attachment modules is not limited to the embodiments and drawings. The drawings and their detailed description are not intended to limit the embodiments to any particular form. Rather, the present invention covers all modifications, equivalents, and alternatives falling within the scope of the inventory management system and method for performing each subset of inventory management tasks using functionally attached modules as defined by the appended claims. The headings used herein are for organizational purposes only and do not limit the scope of the detailed description or the claims. As used herein, the term "may" is used in a permissive sense (i.e., meaning possible) rather than a required sense (i.e., meaning must). Similarly, the terms "include," "including," and "includes" mean including, but not limited to. DETAILED DESCRIPTION OF THE INVENTION

[0026] Various embodiments of a method and apparatus are described for performing inventory control tasks in an inventory control system. The following detailed description provides a thorough understanding of claimed subject matter. However, claimed subject matter may be practiced without these specific details. In other instances, methods, apparatus, or systems known by one of the prior art have not been described in detail to avoid obscuring claimed subject matter.

[0027] Some portions of the detailed descriptions are presented in terms of algorithms or symbolic representations of operations on binary digital signals stored within a memory of a particular apparatus or special purpose computing device or platform. The term specific apparatus or the like in this specification may include a general purpose computer that is programmed to perform particular functions pursuant to instructions from program software. Algorithmic descriptions or symbolic representations are examples of techniques used by those skilled in the signal processing or related arts to convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of operations or similar signal processing leading to a desired result. In this context, operations and processing involve physical manipulations of physical quantities. Usually, though not necessarily, such quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. Principally for reasons of common usage, such signals are referred to as bits, data, values, elements, symbols, characters, terms, numbers, codes, or the like. However, all of these and similar terms are to be associated with appropriate physical quantities and are merely convenient labels.

[0028] Unless otherwise stated, discussions using terms such as "processing," "computing," "calculating," "determining," and the like refer to the operation or processing of a specific device, such as a special purpose computer or similar special purpose electronic computing device. Thus, in the context of this specification, a special purpose computer or similar special purpose electronic computing device can manipulate or transform signals. The signals are typically represented as physical electronic or magnetic quantities within the memory, registers or other information storage, transmission or display devices of a special purpose computer or similar special purpose electronic computing device.

[0029] Please refer to the embodiments of the present invention. Examples of these are shown in the drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like items.

[0030] The present embodiment includes an automated guided vehicle, which is a vehicle that can be configured to perform various tasks associated with inventory control operations. To maintain a high degree of modularity, the automated guided vehicle is configured and operable to perform a first subset of one or more inventory control tasks and to interact with any of a plurality of interchangeable, functionally attached modules to perform a further subset of one or more inventory control tasks. A subset of the functional attachment modules are vertically and horizontally movable so that they can be moved to various locations within the inventory control facility as needed. A facility may be, for example, an inventory distribution center where inventory items are stored for future shipment to a retail location and / or a continuous distribution center where inventory items are shipped directly to retail customers.

[0031] Each function-attached module in the group of function-attached modules has at least one function, capability, or physical attribute that is lacking in another group of automated guided vehicles and function-attached modules. The vehicle, the functionally attached module, and the automated guided vehicle and the particular functionally attached module paired with that vehicle at any given time work together synergistically to perform various tasks according to the manner in which each automated guided vehicle operates. By replacing one functional attachment module or set of functional attachment modules with one or more other functional attachment modules, any vehicle can be easily configured to perform an alternative or additional set of inventory management tasks. Thus, automated guided vehicles retain their usefulness in inventory control systems even as the complexity of the system increases to achieve greater inventory segmentation (e.g., to accommodate larger SKU counts), larger order picking volumes, and / or higher throughput requirements.

[0032] Additionally, an indefinite-term association may be formed between the automated guided vehicle and the functional attachment module to enable performance of a second subset of inventory control tasks. All of the functionality required to complete this second subset of inventory control tasks is provided by the combination of the automated guided vehicle and the functional attachment module. The association formed between the first function attachment module and the vehicle is achieved by direct engagement of components of the automated guided vehicle with components of the function attachment module. In other cases, performing a second subset of inventory control tasks further requires the use of an additional or second functionally attached module. The second function attachment module functions as an adapter between the automated guided vehicle and the first function attachment module. As soon as the assigned subset of inventory management tasks is completed and / or the use of any or all of these components is required for some other task or tasks, the association between the vehicle and the functional accessory module is terminated.

[0033] Order picking systems, such as mail order or e-commerce warehouses, supply chain inventory distribution centers, cross-dock facilities, custom order manufacturing facilities, or any other type of inventory system, are generally distinguished from one another according to: (i) who and / or what is picking items; (ii) who and / or what is moving within the picking area; (iii) whether different picking zones are connected by conveyors; and (iv) what picking policies are applied. Available picking systems include picker-to-parts, pick-to-box, pick-and-sort, parts-to-picker, and fully automated picking. The level of automation required for implementation gradually increases as order picking systems move from picker-to-parts to fully automated picking systems.

[0034] The most basic order picking system in use today is the picker-to-parts system. In this case, a human picker walks (or drives) along the aisles and manually picks items from their storage locations. In a low-level picking system, items are stored in storage racks or containment bins that are easily reachable by pickers. In a high level picking system, pickers use lift trucks or cranes to reach items stored in elevated storage racks. Both types of picker-to-parts systems are easy to implement, modify, and scale, but are typically limited to applications where both the pick volume and the number of inventory items (e.g., SKUs) are small. This limitation is due to the rapid decline in productivity that accompanies increased travel time.

[0035] A zone pick system is similar to a picker-to-parts system in that the picking activity is performed by a human picker. Meanwhile, the areas in which these workers perform their tasks are divided into separate zones. These picking zones are connected by conveyors. Orders are picked sequentially by zone and sorted according to their destination. Each customer order generally corresponds to one picking box, which is passed to the next zone as soon as all required items have been picked in the current zone. An efficient pick-to-box system is one in which the workload is balanced among the various picking zones. Pick-to-box systems are often used in situations where many small items are in stock, but the orders themselves are generally small in number.

[0036] FIG. 1A is a perspective view of an inventory control system 10 including a plurality of autonomous or automated guided vehicles 12 . Each automated guided vehicle 12 can be configured to interact with functional accessory modules to assist in the part picking process and perform a subset of inventory control tasks. In FIG. 1A, the inventory control system 10 implements a "picker-to-parts" scheme or alternatively a zone scheme. In either case, inventory items (not shown) are stored in and retrieved from storage racks generally designated 14 . The storage rack 14 defines rows and columns of storage cells sized and arranged to receive containers 16 that house items. The bins 16 are located at a low enough height that they can be easily reached by a human picker P1.

[0037] As an incremental development to a picker-to-part system or approach that already uses low-level storage racks 14 and bins 16, the inventory control system 10 shown in FIG. 1A may be implemented simply by adding an automated guided vehicle 12 and a plurality of functional attachment modules 18 that collectively form a first group of functional attachment modules. Each of the first group of functional accessory modules 18 includes a base 20, a vertical support or stalk 22 extending upwardly from the base 20, and a plurality of item storage cells 24 attached to the stalk 22. In the embodiment of FIG. 1A, a user terminal having a touchscreen display 26 is also attached to the stalk 26 and accommodates the display of various instructions to one or more pickers and the input of confirmations of acceptance according to the inventory control tasks to be performed by each functional attachment module 18. The same picker that transfers an item from one of the storage racks 14 to one of the functional attachment modules 18 accompanies that functional attachment module to a packing station, such as station S1 or station S2. At the packing station, the items are transferred into an automated guided vehicle in preparation for shipping.

[0038] In implementing a zone pick scheme using an automated guided vehicle 12 and functional attachment modules 18, items are removed from inventory by a picker working in a first storage area and placed in one or more storage cells 24 of a selected functional attachment module 18. The selected function-attached module 18 is then moved to a second storage area (not shown) without the picker accompanying it. In the second storage area, another picker removes additional items from inventory and transfers these items to one or more storage cells of the selected functional attachment module 18 . In this manner, the function attachment module 18 can be configured to act as a conveyor connecting different picking zones.

[0039] The functional accessory module 18 is operable in conjunction with the automated guided vehicle 12 to perform inventory management tasks consistent with a pick-and-sort technique, also known as a wave picking system. A wave picking configuration consists of one or more picking areas and one or more sorting areas. Inventory items associated with multiple customer orders are picked in batches. After picking, the batch of items may be placed in a respective function attached module 18 such that, rather than on a transport conveyor, the function attached module 18 transports the picked items to a sortation area (not shown). Pick and sort systems typically operate by picking waves, where all orders are sorted before the next wave is released.

[0040] Referring now to FIG. 1B, a perspective view of an inventory control system 30 is shown, which includes the existing elements of the inventory control system 10 shown in FIG. 1A. In particular, inventory control system 30 maintains automated guided vehicles 12 as shown in FIG. 1A, and optionally further includes storage racks 14, bins 16, and a first group of pre-acquired functional attachment modules. The inventory control system 30 of FIG. 1B includes a number of further function attachment modules, such as a function attachment module 40 of a second group of function attachment modules, a function attachment module 50 of a third group of function attachment modules, and so on. Furthermore, the automated guided vehicle 12 is configured to interact with each of the function attachment modules 40 and 50 to synergistically perform a subset of inventory management tasks that are different from those performed by interacting with one of the function attachment modules 18.

[0041] When picking items in order fulfillment, a distinction is made between two types of items: fast moving items and slow moving items. Fast moving items are inventory units that are needed frequently and / or in large quantities. Slow moving items, on the other hand, are inventory items that are needed less frequently or in smaller quantities. It is possible for items to move from one of these two categories to the other. This movement may be bidirectional, for example, due to the cyclical nature of consumer demand depending on the time of year (eg, back to school, seasonal items, Christmas sales, etc.). In some cases, new products introduced into inventory may experience high growth rates in demand such that the product falls into the fast moving category and remains there for an extended period of time. Conversely, a shift to a slow-moving category may portend a steadily declining popularity of a mature product. The ability to deploy additional and / or different types of functional accessory modules as needed, such as inventory management system 30 shown in FIG. 1B, allows operators of warehouse or inventory-based distribution center facilities to dynamically adapt to both short-term and long-term shifts in inventory item demand.

[0042] In FIG. 1B, inventory control system 30 includes a plurality of multi-level storage racks 60 . The storage rack 60 defines a number of storage surfaces 62, 64, and 66. Each functional accessory module 40 includes a base 42 that is sized and configured to fit under any storage rack 60 and be placed therein by one of the automated guided vehicles 12, and the base 42 is docked to the automated guided vehicle 12. As described below, each automated guided vehicle 12 is operable to lift the functional accessory module 40 with which it is associated and to lift the storage rack 60 under which the functional accessory module 40 is located. The automated guided vehicle 12 paired with the functional accessory module 40 is further operable to transport the lifted storage rack 60, for example, from one of the positions occupied by storage racks 60a, 60b, and 60c to one of the positions adjacent to the picking area P currently occupied by storage racks 60d, 60e, and 60f.

[0043] Referring to FIG. 1B, an automated guided vehicle 12a is shown docked to a storage rack 60f, with both the automated guided vehicle 12a and the storage rack 60f accessible to a picker. Other storage racks 60, e.g., storage racks 60a, 60b, and 60c, are shown positioned within a storage area in symmetrically arranged rows separated by aisles along which the automated guided vehicles can move, with the automated guided vehicles 12 and functional accessory modules 40 performing appropriate inventory control tasks. Such a compact arrangement of storage racks 60 already containing inventory items placed on their storage surfaces allows any storage rack 60 to be transported to a picking area P or sorting area (not shown) using one of the automated guided vehicles, e.g., an automated guided vehicle 12a associated with one of the functional attachment modules 40, when the storage rack 60 is needed to fulfill a requirement for that item in an order fulfillment process. The rows of storage racks, e.g., storage racks 60a, 60b, 60c, serve as buffer areas from which a constant, periodically refreshed flow of inventory containing the storage racks is retrieved and supplied to nearby picking and / or sorting areas. The number of storage racks in such a buffer area may increase or decrease depending on fluctuations in order volume. Additional storage racks 60 may be located in rows separated by one or more aisles at locations further away from the picking and / or sorting areas depending on the relative demand frequency for the inventory items contained in such storage racks.

[0044] As noted above, the inventory control system 30 shown in FIG. 1B further includes a third group of functional attachment modules 50 and a plurality of multi-level storage racks 60 . The storage rack 60 defines a number of storage surfaces 62, 64, and 66. Each functional accessory module 40 includes a base 42 sized and configured to fit under any storage rack 60 and be placed thereon by one of the automated guided vehicles 12, and this base 42 is attached to the automated guided vehicle 12. As described below, each automated guided vehicle 12 is operable to lift the functional accessory module 40 with which it is associated and to lift the storage rack 60 under which the functional accessory module 40 is located. The automated guided vehicle 12 paired with the functional accessory module 40 is further operable to transport the lifted storage rack 60, for example, from one of the positions occupied by storage racks 60a, 60b, and 60c to one of the positions adjacent to the picking area P currently occupied by storage racks 60d, 60e, and 60f.

[0045] In FIG. 1B, inventory control system 30 further includes a multi-level flow rack 70 . Flow racks 70 may be used, for example, to store inventory items that are removed from inventory in larger quantities than the items stored in storage racks 60 . One or more levels of flow racks 70, e.g., upper levels 72, 74, are configured as conveyors that are selectively activated as needed to move inventory items forward to a position nearest one or more operators at the picking and / or sorting stations. As noted above, inventory control system 30 further includes function attachment module 50 of the third group of function attachment modules.

[0046] For example, automated guided vehicle 12 b is sized and configured to dock with, lift, and transport any functional attachment module 50 for replenishing flow rack 70 . To this end, each functional attachment module 50 defines an internal row that is sized and configured to allow any automated guided vehicle 12 to move vertically (upward or downward) within the functional attachment module 50 while in the illustrated position occupied by automated guided vehicle 12b. Such movement allows the automated guided vehicle 12 to rise to a level within any functional attachment module 50 that is aligned with one of the storage levels of the flow rack 70 . Once such alignment is achieved, each automated guided vehicle is operable to perform an inventory transfer task to transfer a container or case of items or a pallet load of items from the face of the automated guided vehicle 12 to the storage level of the flow rack 70 with which the face of the automated guided vehicle is aligned. In FIG. 1B, the automated guided vehicle 12b is shown in the process of transporting a first function-attached module 50 along a path parallel to the flow rack 70. Another functional accessory module 50 is shown interlocked and aligned with the flow rack 70, with the automated guided vehicle there ready to begin the process of lifting and transferring a case 76 to the flow rack 70.

[0047] Referring now to FIG. 1C, a perspective view of an inventory control system 100 is shown, which includes the existing elements of inventory control system 30 shown in FIG. 1B. In particular, inventory control system 100 maintains automated guided vehicles 12 as shown in FIG. 1A, and optionally further includes function attachment module 40, function attachment module 50, portable storage rack 60, and flow rack 70. The automated guided vehicle 12 is used as part of a storage and retrieval assembly, or SAR, which also includes an array of destination areas or storage locations 110 . The storage locations 110 are arranged in rows. Additionally, the SAR of inventory control system 100 includes a guidance system, such as a track (not shown), that vertically guides the automated guided vehicle to reach the destination storage location.

[0048] One of the inventory control tasks assigned to an automated guided vehicle 12 operating as part of the SAR department is to retrieve items from storage locations 110 . This task can be thought of as a series of subtasks, including exiting the current or starting location of the automated guided vehicle, navigating a path for the automated guided vehicle between the starting point and an intermediate destination adjacent to an entry point into the array of storage locations, and aligning the automated guided vehicle 12 with the entry point at the intermediate destination. As a further subtask of the search task, the aligned automated guided vehicle enters the array and maintains its alignment until it reaches a queue, within which it is operated to ascend according to a further subtask, and then reaches a target storage area in storage area 110. As a further subtask of the retrieval process, the loading mechanism of the automated guided vehicle is operated to retrieve the item, move down the queue until the automated guided vehicle is placed on a support surface, and exit the array of storage locations. As a final subtask of the retrieval operation, the automated guided vehicle 12 proceeds along the path to an output station 120 where an operator can retrieve the item from the automated guided vehicle.

[0049] The automated guided vehicle may perform a power replenishment task and then return any remaining items not retrieved by the operator to a storage area. In this regard, rather than operating the automated guided vehicle's transfer mechanism to retrieve the item from the target storage location, the automated guided vehicle simply re-executes the series of subtasks to retrieve the item, except that the transfer mechanism is instead operated to transfer the item from the automated guided vehicle's platform to the target storage location. After the transfer, if there is sufficient power remaining, the automated guided vehicle may proceed to another storage area to retrieve the next item to be retrieved. In this manner, inventory management system 100 includes a plurality of individually controlled automated guided vehicles, e.g., automated guided vehicles 12, that move up and down along tracks within any of a plurality of rows to retrieve items from various storage areas, deliver the items to operators, and then return the remaining items and search for other items.

[0050] Automated guided vehicles 12 working together as part of the SAR deliver and / or retrieve items to and from the storage area 110 . The items may be configured such that the items are stored individually in storage locations. On the other hand, in a typical work environment, items are stored in a storage mechanism, such as a container or platform. For example, items may be stored in containers called totes. A tote may be similar to a carton or box with no lid, allowing an operator to simply reach into the tote at a picking station and retrieve an item. Although the present invention is described as using totes, any of a variety of storage mechanisms may be used, such as pallets or similar platforms.

[0051] The storage locations 110 of the inventory control system 100 shown in FIG. 1C may be in any of a variety of configurations. For example, the simplest configuration is that of a shelf that supports items, or that of a container that holds items. Similarly, the inventory control system 100 may include one or more brackets that cooperate with the storage mechanism to support the storage mechanism at the storage location 110 . For example, the storage location includes a bracket similar to the shelf bracket for supporting one of the totes, as shown in FIG. 1C.

[0052] A subset of automated guided vehicles 12 can thus be configured to perform a subset of inventory management tasks related to storing and retrieving totes T containing items from storage area 110 and delivering totes T to one or more delivery stations 120 where an operator can retrieve one or more items from the tote. Although the above description has been of a single automated guided vehicle performing all subtasks, including the search task, the subtasks of a task may be assigned to multiple automated guided vehicles 12 . For example, a first vehicle exiting the array of storage areas 110 may transfer the items it retrieved to a second vehicle, which then completes the retrieval task by delivering the items to one or more delivery stations 120. After the operator retrieves the item, the same vehicle or a further automated guided vehicle 12 moves the tote T away from the delivery station 120 and returns the tote to one of the same or a different storage location 110.

[0053] From the above high-level description of Figures 1A-1C, it can be seen that automated guided vehicle 12 is operable in some operational modes to synergistically cooperate with one or more functional attachment modules to perform various sets of inventory control tasks, and in other operational modes to perform other inventory control tasks that do not require association with any functional attachment modules, e.g., functional attachment module 40, functional attachment module 50. The manner in which such functionality is implemented is described below with reference to Figures 2A-2I. 2A to 2I show the automated guided vehicle, and the other figures below show the configuration of the function attachment module itself.

[0054] 2A-2I, an automated guided vehicle 200 is shown that is adapted to perform inventory control tasks in, for example, any of the material handling systems shown in FIGS. 1A-1C. Each automated guided vehicle that is delivered is an automated guided vehicle 200 that has a first drive system, a second drive system, and an on-board power supply. In a configuration using an array of storage areas arranged in rows and accessible by a guidance system, such as storage area 110 in FIG. 1C, the first drive system cooperates with the guidance system to guide movement of automated guided vehicle 200 along each vertical path segment adjacent to each row of storage areas. And, the second drive system is sized and configured to maneuver the automated guided vehicle 200 over the lower support surface while the first drive system is not engaged with the guidance system. Generally, the lower support surface is defined by one or more areas of the warehouse floor and / or one or more elevated platforms within such warehouse, or a combination thereof.

[0055] Each automated guided vehicle includes a loading and unloading mechanism 210 operable to transfer items, for example, between the platform surface of the automated guided vehicle and one of a plurality of destination areas 110 . As shown in FIG. 2A, the platform surface in this example is defined by the outer surfaces 211 of a number of rollers. Further, as will be described with reference to Figures 4B and 4C, each automated guided vehicle 200 may optionally include a clutch mechanism that operates to connect and disconnect the transmission of power from the motor of the first drive system or the second drive system to the loading and unloading mechanism, as necessary, so that the loading and unloading mechanism is operable only while the first drive system and the second drive system are not operating to drive the automated guided vehicle.

[0056] The automated guided vehicle 200 may include any of a variety of mechanisms for loading items onto the automated guided vehicle and unloading items from the automated guided vehicle into one of the storage areas. Additionally, the loading and unloading mechanism 210 may be customized for a particular application. The transfer mechanism 210 includes a movable member that engages an item stored in a storage location and pulls the item onto the automated guided vehicle. In particular, the automated guided vehicle includes one or more movable members configured to move toward the totes in the storage locations. After the movable members engage the tote, each movable member moves away from the storage position, thereby pulling the tote onto the automated guided vehicle 200.

[0057] 2A, 2B, and 2G to 2I, the loading / unloading mechanism 210 includes two endless carriers, for example, drive belts, such as drive chains 214a and 214b as shown. Along each endless carrier, eg, drive chain 214a, 214b, there is provided a movable member in the form of a movable pin 212a, 212b (FIGS. 2B, 2D, 2E). Each pin 212a extends inwardly toward the longitudinal centerline of the automated guided vehicle. Optionally, a tubular bar member (not shown) may house each pin 212 a , 212 b and extend across the width of the vehicle 200 .

[0058] A motor in the second drive system drives the drive chain to selectively move the drive chain and pins 212a, 212b toward or away from the storage position. For example, when an automated guided vehicle approaches a storage location to retrieve tote T (Figures 2G-2I), the drive chain may drive movable pins 212a, 212b toward the storage location so that the pins (and the rod connecting these pins, if present) are positioned below a groove or notch in the bottom of the tote. The automated guided vehicle moves upward a small distance until the pins 212a, 212b (or rods) are positioned in the grooves or notches, as shown in FIG. 2I. The drive chain then reverses, moving the pins 212 a and 212 b away from the storage position 100 . Because the pin engages the tote T in the notch, the tote is pulled onto the surface of the automated guided vehicle as the pin moves away from the storage position. In this manner, the loading and unloading mechanism 210 is operable to retrieve items from storage locations. Similarly, when storing an item in a storage location, such as location 110 in FIG. 1C, drive chains 214a, 214b of loading / unloading mechanism 210 drive pin 212 toward the storage location until the item is within the storage location. The automated guided vehicle then releases the tote by moving downward to disengage the pin from the tote.

[0059] In the above description, the transfer mechanism 210 comprises endless carriers in the form of drive chains 214a, 214b and corresponding movable pin members 212a, 212b which may optionally be interconnected by a single tubular member. Such a configuration is suitable for retrieving totes containing items from storage areas arranged in vertical rows, with the tubular members and / or the rods extending therebetween engaging notches on the underside of the totes near their tips. The totes are placed in respective zones of n deep storage cells, where n represents the maximum number of totes that can be accommodated, one each, in a generally horizontal plane if all the totes are connected to one another and placed in one of the n deep cells. FIG. 1C shows a vertical array of such storage areas or cells, generally designated 110.

[0060] As shown in FIG. 2H, two or more totes, eg, totes T1 and T2, are coupled and uncoupled to one another using mating connectors 283a and 283b. Totes T1, T2 are coupled and uncoupled from one another by a series of lift and move apart movements performed by the movement of vehicle 210. Additionally, the loading and unloading mechanism 210 is actuated by a second drive mechanism to pull the forward facing (“leading edge”) tote onto rollers 211 (FIG. 2G) so that it is fully supported by the automated guided vehicle 200. This pulling action propels the trailing tote (ie, the tote immediately following the leading tote) into position opposite the aisle. The first drive mechanism of the automated guided vehicle 200 is then briefly operated to cause the automated guided vehicle 200 to move a vertical distance sufficient to decouple the leading tote from the trailing tote. Once uncoupling is complete, the second drive system is again briefly operated, this time to position the tote in the center of the automated guided vehicle 200 so that the automated guided vehicle and tote are fully maneuverable vertically within the queue.

[0061] 2A and 2D-2F, the first drive system of the automated guided vehicle 200 includes four gear wheels in the form of gears 220 that are driven to transport the automated guided vehicle along a track that is arranged in a row adjacent to the storage area 110. The gear wheels 220 are mounted on two parallel, spaced-apart shafts 215 shown in FIG. 2F, with two gear wheels positioned along the front end of the automated guided vehicle and two gear wheels positioned along the rear end of the automated guided vehicle.

[0062] In particular, FIG. 2C is a bottom view of the automated guided vehicle 200 shown in FIG. 2A, and FIG. 2F is a side view of the automated guided vehicle shown in FIG. 2A. As shown in FIG. 2C, automated guided vehicle 200 further includes a second drive system sized and configured to drive automated guided vehicle 200 over an underlying support surface, for example, the floor of a warehouse or inventory-based distribution center. In FIG. 2C, the second drive system includes a second motor 250a of the automated guided vehicle 200 and a third motor 250b of the automated guided vehicle 200. In this case, the second motor 250a and the third motor 250b are the first and second motors of the second subset of the plurality of motors. By dynamically controlling the relative speed and / or rotation direction of each of the second motor 250a and the third motor 250b, the automated guided vehicle 200 can be driven in any direction on a lower support surface, such as the lower support surface S shown in FIG. 2F.

[0063] Referring to FIG. 2C, the second drive system includes a first drive member 252a driven by a second motor 250a to rotate about a first axis of rotation A1, and a second drive member 252b driven by a third motor 250b to rotate about a second axis of rotation A2. The first drive member 252a and the second drive member 252b are each sized and configured to engage a respective portion of the lower support surface S for movement of the automated guided vehicle thereon. In the automated guided vehicle shown in FIGS. 2C and 2F, the first rotation axis A1 and the second rotation axis A2 are coaxial, and the first driving member 252a and the second driving member 252b are supported by a horizontal plane. The second drive system of the automated guided vehicle 200 further includes a plurality of omni-directional wheels comprising a first pair of wheels 254a, 254b and a second pair of wheels 256a, 256b. Each of the omni-directional wheels is sized and configured to frictionally engage a respective portion of the lower support surface S (FIG. 2F), and each wheel 254a, 254b, 256a, 256b is fixed to a corresponding drive shaft 258a, 258b, respectively.

[0064] With particular reference to FIGS. 2C and 2D-2F, automated guided vehicle 200 may include a series of guide members 233 depending downwardly from shaft 235. Each guide member 233 is rotatably mounted on the lower part of a shaft 235 . The inventors have now discovered that in some applications, the guide member 233 simplifies the alignment of the automated guided vehicle 200 as it is maneuvered over an underlying support surface and aligned with one or more other structures that it enters while performing its assigned inventory control task. In FIG. 2C, a guide member 233 is disposed along the longitudinal center line L of the automated guided vehicle 200. FIG. 2E shows in cross section the alignment of guide member 233 within a pair of parallel rails mounted on lower support surface S. As shown in Figures 12-13C, rails R1, R2 are positioned below the vertical array of storage cells along a path along which automated guided vehicles 200 enter, exit, and / or operate.

[0065] Next, referring to Figures 3A and 3B, Figure 3A is a front elevational view of the automated guided vehicle of Figures 2A to 2F in a cross section taken along line IIIA-IIIA in Figure 2A, and Figure 3B is a bottom view of the automated guided vehicle of Figures 2A to 2F with the clutch mechanism partially disassembled to expose its internal configuration. As shown in FIG. 3A, the first drive system further includes a pair of inner driven pulleys 224a, 224b and a pair of outer pulleys 222a, 222b that, when driven by respective drive belts 226a, 226b, rotate gear wheels 220 mounted on the same shaft, thereby driving the automated guided vehicle 200 vertically within the column (along the drive plane of the track). The driven pulleys 224a, 224b rotate freely about their axes and maintain tension on the drive belts 226a, 226b. Each of the outer pulleys 222a, 222b is mounted on a shaft 215 and is fixed relative to this shaft 215. The first drive system further includes a pair of reversing gears 228a, 228b rotated by a first on-board motor 230 (FIG. 3B). Thus, when driven, the drive belts 226a, 226b drive the outer pulleys 222a, 222b, respectively, and this rotational movement of the outer pulleys 222a, 222b causes the gear wheels 220 mounted on their corresponding shafts 215 to rotate. Thus, when automated guided vehicle 200 is moving vertically, gear wheel 220 supports the weight of the automated guided vehicle and one or more items thereon.

[0066] In Figures 3A and 3B, shaft 215 is rotatably mounted within housing 232 such that their spacing remains fixed relative to one another. As described below, the fixed spacing between axes 215 requires an alignment step with the guidance system (e.g., track) before an automated guided vehicle can enter the row that extends between the vertical array of storage areas 115 (FIG. 1C) and that is provided with this guidance system.

[0067] In another embodiment (not shown), the components of the first drive system, such as gear wheel 220 and shaft 215, may be mounted within housing 232 to move these components inward, reducing the requirement for precise alignment while eliminating the risk of damage to either gear wheel 220 or the guide system. In the latter type of embodiment, an automated guided vehicle intended to transport large loads may require motor-driven means to temporarily reduce the spacing between axes 215, thereby accommodating the automated guided vehicle's entry into one or more rows between storage areas.

[0068] 3A and 3B, it can be seen that the first motor 230 is operatively coupled to the reversing gears 228a, 228b to drive the drive belts 226a, 226b for synchronous rotation with the shaft 215 and its corresponding gear wheel 220. On a track or other guidance system, the first drive system of the automated guided vehicle 200 is thus configured to synchronously drive the automated guided vehicle 200 in the vertical direction. In particular, each gear wheel 220 is coupled to one end of one of the shafts 215 in a manner that substantially prevents rotation of the gear relative to the drive shaft. In this way, each shaft synchronously drives the two gears to which it is attached. Furthermore, since both axes are driven synchronously, all four gears are driven synchronously.

[0069] A drive motor 230 is used to drive the two axes. In this example, pulleys 222a and 222b serve as timing pulleys that are fixedly connected to shaft 215 to prevent rotation of the pulleys relative to the shaft. Similarly, timing pulleys (not shown) are coupled to reversing gears 228 a and 228 b that are driven by drive motor 230 . Drive belt 226a connects timing pulley 222a to a timing pulley driven directly by drive motor 230 via reversing gear 228a, and drive belt 226b connects timing pulley 222b to a timing pulley driven indirectly by drive motor 230 via reversing gear 228b. Each of the drive belts 226 a , 226 b is a timing belt such that the rotation of the drive motor 230 is precisely linked to the rotation of the shaft 215 .

[0070] Besides the single motor configuration shown in FIGS. 3A and 3B, there are a variety of other mechanisms that can be used to synchronously drive the shafts 215. For example, a pair of drive motors may be used to drive the shafts, and the drive motors 230 may be synchronized. The drive motor 230 includes a sensor operable to detect the rotation of the motor and thereby measure the distance traveled by the automated guided vehicle. Gear 200 is fixedly coupled to the shaft, while shaft 215 is synchronously coupled to drive motor 230, so that the vertical distance traveled by the automated guided vehicle can be precisely controlled by correlating it to the distance displaced by drive motor 230. For example, the sensor 252 may be a sensor such as a Hall sensor. The sensor 252 detects the rotation of the motor and sends a signal to a central processing unit, which calculates how far the automated guided vehicle 200 has traveled along the specified path based on known information about the path and the rotation detected by the sensor 252 relative to the motor.

[0071] Referring to Figures 2C, 3B and 4A-4G, an embodiment of automated guided vehicle 200 is shown that further includes a clutch mechanism 400 (Figures 4B and 4C) that can be engaged (Figure 4C) and disengaged (Figure 4B) to initiate and terminate the transmission of power from the drive motor of the second drive system to the transfer mechanism, thereby allowing the second drive system to be operated independently of the transfer mechanism. The clutch mechanism 400 is configured as two clutch subassemblies 400a, 400b arranged symmetrically about the longitudinal centerline of the automated guided vehicle 200, as shown in Figures 2C and 3B. In FIGS. 4B and 4C, only the first clutch subassembly 400 a can be seen, and the first clutch subassembly 400 a includes a first rotatable carriage 410 . Meanwhile, returning to FIG. 3B, the second clutch subassembly 400 b is configured similarly to subassembly 400 a and thus includes a second rotatable carriage 412 .

[0072] As shown in FIG. 4B, for example, the first clutch subassembly 400a includes a rotatable carrier, e.g., first rotatable carrier 410, that maintains a first angular orientation relative to the lower support surface S while the total weight of the automated guided vehicle 200 is distributed among the wheels 254a, 254b, 256a, 256b, 252a, and 252b. Comparing Figures 4C and 4B, it can be seen that as the automated guided vehicle 200 moves away from the vertical lower support surface S, the rotatable carrier 410 (and 412) is biased by the compression coil spring 414 to a second angular position, which is reached when the automated guided vehicle 200 reaches a rise from the lower support surface S having at least a dimension g1, as shown in Figure 4C. Returning to FIG. 3B, the first driven member 270 is rotatably coupled to the first rotatable carrier 410, and the first endless loop member 274 transmits rotational power to the first driven member 270. Similarly, a second driven member (not shown) of the second clutch sub-assembly 400b is rotatably coupled to the second rotatable carrier 412, and a second endless loop member (not shown) transmits rotational power to the second driven member in a manner similar to that described with respect to the first clutch sub-assembly. The first endless loop member 274 is a belt, although a chain may alternatively be used without departing from the spirit and scope of the present disclosure.

[0073] 4B and 4C, the subassembly 400 a of the automated guided vehicle 200 includes the first pulley 280 . The first pulley 280 and the first driven member 270 of the subassembly 400 a are driven by the second motor of the automated guided vehicle 200 . Similarly, although not shown, the second pulley and the second driven member of the subassembly 400b are driven by a third motor of the automated guided vehicle 200. The first pulley 280 and the second pulley are sized and configured to engage the first endless loop member 274 and the second endless loop member, respectively, and to drive the first driven member and the second driven member whenever their corresponding drive motors are rotating. In other words, regardless of whether the clutch mechanism subassemblies 400a, 400b are engaged to drive the transfer mechanism, the first driven member 270 and the second driven member rotate when the second motor and the third motor, respectively, rotate.

[0074] As described above, the second and third motors are coupled and engage the transfer mechanism only when the automated guided vehicle is raised by dimension H relative to the lower support surface S (FIG. 4C). Such lifting causes the rotatable carriage 410 to pivot away from a first angular orientation shown in FIG. 4B to a second angular orientation shown in FIG. 4C. The second motor and the loading / unloading mechanism are coupled together by the third driven member 272 pivoting and drivingly engaging with the first driven member 270 in the clutch mechanism subassembly 400a. Similarly, although not shown, the third motor is coupled to the transfer mechanism by the fourth driven member 272 pivoting and drivingly engaging with the second driven member in the clutch mechanism subassembly 400b.

[0075] As shown in Figures 4A-4C, although only the fourth driven member 272b is shown in Figure 4C, rotation of the engaged third and fourth driven members causes the first sprockets 290a, 290b to rotate, which in turn causes the first chain 214a and the second chain 214b to move the pins 212a (Figure 4A) and 212b (Figure 4B) toward or away from the container to be transferred to or from the automated guided vehicle 200. As shown in FIG. 4B, when the wheels of the automated guided vehicle 200 are again placed on the lower support surface S, the third driven member and the fourth driven member 272b again decouple from the first driven member and the second driven member, respectively. In this way, the continuous operation of the second and third motors of the automated guided vehicle to drive the automated guided vehicle 200 on the lower support surface S does not have any effect on the transfer mechanism 210.

[0076] It may be desirable for automated guided vehicle 200 to be able to load and unload types of items other than those configured as totes that are sized and configured to contain multiple inventory items. Such other types of items may be, by way of example, boxes, cartons, trays, etc., or any combination thereof, and may contain one or more inventory items. Such items may be accommodated by a loading and unloading mechanism 210 that includes loading and unloading aids. 2G and 4A-4D, as sprocket 290 rotates, first chain 214a and second chain 214b drive sprocket 217, which in turn rotate a corresponding one of the rollers, e.g., roller 211 (FIG. 2G). The direction in which the pair of sprockets 217 are rotated determines whether the rollers of the loading and unloading mechanism 210 operate to assist in loading or unloading items.

[0077] 4D and 4E are side views of the automated guided vehicle 200 of FIGS. 2A-2F, with the lateral exterior cover plates omitted to reveal an optional actuator mechanism 400 having a power imparting member 402 selectively movable between a first position (FIG. 4D) and a second position (FIG. 4E). FIG. 4F is an expanded view of the actuator mechanism 400 shown in FIGS. 4D and 4E, with its power applying member 402 in a first, unpowered position. FIG. 4G is an expanded view of the actuator mechanism shown in FIGS. 4D-4F, showing the force applying member 402 in a second force applying position.

[0078] As described above in the description of FIG. 4F, the gear wheels 220 are mounted on two parallel, spaced-apart axes, such as the axes 215 shown in FIG. 2F, with two gear wheels positioned along the front end of the automated guided vehicle and two gear wheels positioned along the rear end of the automated guided vehicle. The optional actuator mechanism 400 includes a threaded portion 404 on each shaft 215 and a pair of carriers 406 . Each carrier 406 has a corresponding threaded bore sized and configured to receive the threaded portion 404 of the shaft 215 and carries one of a pair of power imparting members 402 . The power imparting member 402 is a roller that is freely rotatable within the carrier 406 about an axis of rotation that is transverse to the axis defined by the shaft 215 .

[0079] To obtain better steering control, such as differentially driving a pair of front or rear omni-directional wheels, the inventors have now discovered that the power imparting member 402 can be selectively actuated without the need for a dedicated motor. Rotation of motor 230 (FIG. 3B) causes shaft 215 to rotate, which in turn causes carrier 406 to move until a stop position is reached where continued motion of shaft 215 no longer contributes to the movement of carrier 406. When in the position shown in FIG. 4G, each force applying member 402 applies a normal force to one face of the wheels, for example, 252a, 252b, while the wheels are driven by the second and third motors, respectively. Such actuation of the power imparting member 402 increases the frictional contact of the wheels 252a, 252b, thereby providing better directional control as the automated guided vehicle 200 moves across the lower support surface S (FIG. 4G). While the wheels 252a, 252b are only needed while the vehicle is outside the array of the storage area 110, the motor 230 and axle 215 can serve two purposes.

[0080] 3B and 4D-4G, an automated guided vehicle 200 includes a first pair of motor-driven omnidirectional rollers and a second pair of motor-driven omnidirectional rollers, where the first omnidirectional roller of each pair is sized and configured to rotate about a first axis of rotation and the second omnidirectional roller of each pair is driven to rotate about a second axis of rotation; a fifth roller driven by one of the first and second motors; and an actuator movable from a first position to a second position to selectively urge the fifth roller in a direction toward a lower support surface S, whereby a surface of each of the first and second pairs of omnidirectional rollers and a surface of the fifth roller are sized and configured to contact the lower support surface S while the actuator is maintained in the first position, and movement of the actuator to the second position transfers a load from the omnidirectional rollers to the fifth roller.

[0081] The automated guided vehicle 200 may be powered by an external power source, for example, by contact with a continuous charging rail or by use of an inductive power transfer coil, both of which serve to provide the power necessary to drive the vehicle. On the other hand, the automated guided vehicle 200 includes an on-board power supply that provides the necessary power for both the first motor 230 and the motor that drives the second drive system. The on-board power supply is rechargeable. In this case, the power source may include a power source such as, for example, a rechargeable battery, an ultracapacitor bank such as, for example, capacitor 240 (FIG. 3B), or a combination thereof. For example, ultracapacitors can tolerate very high amperage during charging operations. By using high currents, ultracapacitors can be charged in a relatively very short time, on the order of seconds or minutes, compared to the hours that would be required to charge a suitable battery. However, the process of replacing a discharged battery with a charged battery can be automated as part of the process of operating the vehicle.

[0082] If a charging rail is used, each automated guided vehicle 200 includes contacts for charging the power source. The vehicle may include spring-loaded copper brushes, with the brushes biased outward. As will be explained below, the brushes cooperate with a charging rail to charge the power source. For example, a pair of charging rails (not shown) may be provided along the line along which the automated guided vehicle 200 travels during a sequence of storage and / or retrieval tasks. Alternatively, vertical and / or horizontal charging rails may be provided in a charging station (not shown) located near delivery station 120 (FIG. 1C).

[0083] The charging rail is a conductive strip that is connected to a power source. Charging contacts on the automated guided vehicle 200 engage the conductive strips to charge the ultracapacitors. In particular, the biasing members on the brushes bias the brushes outwardly toward the charging contacts. The electricity flowing through the charging contacts constitutes a high amperage, low voltage source capable of charging the ultracapacitor in a time frame on the order of seconds or minutes, depending on the amount of power consumed during the inventory task or sequence of subtasks.

[0084] Because the power provided by an ultracapacitor may only last for a few minutes, an automated guided vehicle using an ultracapacitor as a power source may charge as the automated guided vehicle moves through a loading line and / or may use charging stations located along the route taken when performing inventory control tasks that require association with one or more functional attachment modules, such as functional attachment module 18 (FIGS. 1A and 1B) or functional attachment modules 40 and 50 (FIGS. 1B and 1C).

[0085] Each automated guided vehicle may include a load sensor to detect the loading of items onto the automated guided vehicle. The load sensor ensures that the item is properly positioned on the automated guided vehicle. For example, the load sensor may include a force sensing device that detects changes in weight, or an infrared sensor that detects the presence of an item.

[0086] The automated guided vehicles, or AGVs, in FIGS. 1A-1C may be semi-autonomous, or alternatively, fully autonomous. In the latter case, a number of non-contact systems have been proposed to continuously calculate the actual position of the automated guided vehicle in absolute coordinates and to re-align the automated guided vehicle by resetting the navigation parameters (i.e., X, Y and heading) to null out the accumulated errors. Any of these may be used in performing position referencing for automated guided vehicles in an inventory control system. Such referencing systems may be ultrasonic, RF or optical in nature, with ultrasonic and optical being particularly suitable for indoor use. Of these latter two categories, optical systems are generally more accurate and therefore have been more widely adopted in commercial practice.

[0087] The position detection system uses a scanning mechanism that operates using fixed position references strategically placed at predetermined inspection locations. Such scanning mechanisms may include fixed beacon active emitters, scanning emitter / detectors using passive retroreflective targets, scanning emitter / detectors using active transponder targets, and rotating emitters using fixed detector targets.

[0088] The automated guided vehicle is based on a scanning laser triangulation scheme (SLTS) to provide position updates for the on-board dead reckoning system of the automated guided vehicle. For example, a laser emitter rotating at 2 rpm illuminates a passive retroreflective barcode target mounted on a wall or support column at a known location approximately 15 meters away from the automated guided vehicle. The barcode is used to provide positive identification of the reference target and to eliminate ambiguity due to spurious reflections from other reflective surfaces in the work area. The on-board computer of each automated guided vehicle calculates the XY position updates by simple triangulation and nulls out the cumulative dead reckoning error.

[0089] Additionally, each automated guided vehicle 200 may employ retroreflective targets located throughout the work area to allow each automated guided vehicle to measure distance and angular orientation. A servo-controlled rotating mirror on the automated guided vehicle pans the near-infrared laser beam through a 90 degree horizontal arc with an update frequency of, for example, 20 Hz. As the beam sweeps over a target of known dimensions, the detector detects the reflected signal for a finite period of time. If the retroreflective targets are all the same size, the signal produced by a nearby target will be of longer duration than the signal of a distant target. The angle measurement begins when the scanner begins to sweep from right to left, and the timing sequence ends when a reflected signal is detected.

[0090] As a further position referencing technology that may be used in automated guided vehicles, laser-based scanning beacon systems use cooperating electronic transponders with passive reflectors to calculate position and orientation. Such a scanner mechanism includes a rotating mirror mounted at an angle of, for example, 45 degrees to the vertical axis of an incremental optical encoder. To improve heading accuracy, a timer interpolates between encoder counts. The fan-shaped beam diverges vertically with a spread angle of, for example, 4 degrees to ensure long-range target detection while traveling on irregular floor surfaces. Each target is uniquely coded, allowing many (e.g., 32) targets to be processed in a single scan, with the XY position of the automated guided vehicle calculated every 100 milliseconds.

[0091] In one or more autonomous configurations, each automated guided vehicle maintains in memory an internal storage map of its own location in the facility. Additionally, each automated guided vehicle transmits its position on the movement plane, speed, angular direction, and selected route of movement data to other automated guided vehicles in the facility, and the automated guided vehicles receive such data from the other automated guided vehicles. Using the automated guided vehicle data, each automated guided vehicle maintains a dynamically updated map reflecting the locations of all automated guided vehicles in one or more particular zones of the inventory control facility to which the automated guided vehicle is assigned. When dynamically updated location data is available locally at each automated guided vehicle, tasks may be assigned to the automated guided vehicles by the central controller 450, and the route segments that the automated guided vehicles will take to reach one or more locations where elements of the assigned task are to be performed may be selected by the automated guided vehicles.

[0092] Each automated guided vehicle is configured to execute, by its local processing unit, steps of a navigation process stored in memory, which steps cause the automated guided vehicle to travel the shortest distance from the automated guided vehicle's current position to a destination where the next one or more subtasks of the assigned task should be performed. And while central controller 450 need not be configured to perform traffic control and collision avoidance functions (unless a backup control scheme is desired), instead central controller 450 may be configured to transmit signals indicating instructions that identify the next task or tasks to be assigned to each automated guided vehicle and specify the various locations within the inventory control facility where these tasks should be performed. Meanwhile, the automated guided vehicle may be configured to send signals to the controller indicating task assignment confirmation, location, updates, status updates (e.g., completed subtasks or subtasks in progress, current power status, etc.), and other information that may be required to assess the relative ability of the automated guided vehicle to perform tasks awaiting assignment.

[0093] In a fully autonomous scheme, each automated guided vehicle may alternatively use a local processing unit to calculate its speed and direction of movement based on detected markings placed on underlying support surfaces in one or more zones of the inventory control facility, exchange its position data with other automated guided vehicles in the inventory control facility, and maintain a dynamically updated local map to achieve a form of decentralized traffic control as described above using other location detection methods.

[0094] In a semi-autonomous configuration of automated guided vehicles, the central controller 450 provides traffic control functionality necessary to prevent collisions between the automated guided vehicles and / or with potential obstacles to vehicle movement that may be present in one or more zones of the facility to which a subset of the automated guided vehicles are assigned, for example. Such a central controller 450 receives current position and bearing data in the form of update signals transmitted from the automated guided vehicle 200 . In an embodiment, the received position and bearing data is compared to estimates derived by the controller based on previous speed and heading commands sent from the controller to the automated guided vehicle. Based on this comparison, the central controller 450 may determine whether corrections to one or more of the speed and direction of the automated guided vehicle are necessary to prevent a collision, and if so, may send these instructions to the automated guided vehicle.

[0095] In a semi-autonomous configuration, each automated guided vehicle 200 may include a reading device for reading indicia located on the surface on which the automated guided vehicle is traveling and / or located at a location within an access queue that is aligned with the array of storage areas 115 (FIG. 1C). Each mark in the first group of marks corresponds to a unique location, forming a grid of locations. These locations may be stored in a data table in memory accessible to processors in the automated guided vehicle, central controller 450, or both. By following a designated path that intersects a particular sequence of these markings, each automated guided vehicle may transmit an identifier as it passes a marking and confirm this to the central controller 450, thereby achieving semi-autonomous guidance of the automated guided vehicle via commands sent from the central controller to the automated guided vehicle. From this information and other data reported by each automated guided vehicle, the central controller 450 can ascertain the speed, direction and path of travel of each automated guided vehicle. This central controller 450 then uses the speed and direction data to implement collision avoidance policies, assign inventory management tasks according to each automated guided vehicle's location and power reserve status, and maintain appropriate distances for personnel allowed in the area for safety purposes.

[0096] Additional markings may be provided in the access queue or on the tote itself at locations adjacent each of the storage locations 115 (FIG. 1C). In this case, each indicia may include a unique bar code, and a reader on each automated guided vehicle 200 may scan the area around the storage location 115 to which the item is to be delivered or retrieved. Data held by the central processing unit 450 regarding the route the automated guided vehicle 200 should take, and data based on data regarding the rotation of the drive motor regarding the distance traveled by the automated guided vehicle, may be sufficient to determine whether the automated guided vehicle 200 is located in an appropriate storage position within the storage area 115. Meanwhile, markings adjacent to storage areas allow automated guided vehicle locations to be checked for redundancy before items are deposited at or retrieved from the appropriate storage locations. Thus, the scanner may operate to scan and read information regarding the storage location at which the automated guided vehicle is parked. If the scanned data indicates that the storage location is an appropriate storage location, the automated guided vehicle unloads the item into the storage location. Similarly, the automated guided vehicle may have a second reader for reading indicia adjacent the rear end of the automated guided vehicle. The second reader may be used in applications where the system is set up to use a first series of storage locations along the front side of the access queue and a second series of storage locations along the back side of the access queue, as shown in FIG. 1C.

[0097] The functionality for autonomous or semi-autonomous guidance of the automated guided vehicle 200 may be incorporated into one or more of the function attachment modules, for example, function attachment modules 18 of FIG. 1A. Such an approach may be beneficial when high accuracy location is required in some zones of an inventory control facility, while a less accurate location approach may be acceptable in other zones. For example, functional accessory module 18 in FIG. 1A is shown as playing a supporting role to warehouse workers and therefore needs to maintain a safe distance while remaining in close proximity to perform one or more support tasks. In light of the above description of various non-limiting examples, it is sufficient to state that various techniques and systems may be used in an inventory control system to coordinate the location of automated guided vehicles and their associated functional accessory modules.

[0098] The automated guided vehicle is positioned within each access row and has a respective inwardly facing gear wheel 220 sized and configured to interact with teeth on the track. Such interaction allows the automated guided vehicle to either raise or lower depending on the direction of rotation of motor 230. The functional attachment module may also include a track having teeth that allows the automated guided vehicle to raise or lower the functional attachment module, e.g., functional attachment module 18 or functional attachment module 50, along with the one or more structures to which the functional attachment module is associated with the automated guided vehicle. For heavy loads (e.g., greater than about 300 kg), a functional attachment module 40 having multiple shelves, such as that shown in Figures 1B and 1C, may be equipped with an internal gear-driven jack mechanism actuated by rotation of gear wheel 220, thereby minimizing the amount of torque required by motor 230 to initiate and maintain the elevation of the functional attachment module during movement over the substrate.

[0099] The processor of each automated guided vehicle controls the operation of the automated guided vehicle in response to signals received from the central processor 450 . Additionally, the automated guided vehicle includes a wireless transceiver that allows the automated guided vehicle to communicate continuously with a central processor as it travels along the track. Alternatively, in some applications it may be desirable to have multiple sensors or indicators along a route that an automated guided vehicle may travel. The automated guided vehicle may include a reader and / or indicator for detecting the sensor signals, and a central processing unit for controlling operation of the automated guided vehicle in response to the sensors or indicators.

[0100] FIG. 5A is a front view illustrating the use of an automated guided vehicle 512 with a first group of functionally attached modules 518 of functionally attached modules. FIG. 5B is a perspective view showing the pre-merge alignment of the automated guided vehicle 512 of FIG. 5A, in which the first base 514 may be implemented as an integral part of the functional attachment module, as one of the functional attachment modules shown in FIGS. 1A-1C and 5A, or as a separate functional attachment module that serves as an adapter between the automated guided vehicle and at least one of these other types of functional modules. If the functional accessory module 518 is expected to carry a heavy load, the base 514 may include an internal jack mechanism actuated by a gear, for example, a gear 515 sized and configured to match a gear wheel 520 of the automated guided vehicle 512.

[0101] Figure 5C is a perspective view showing the post-merge alignment of the automated guided vehicle 512, and the alternative second base 516 may be implemented as an integral part of the functional attachment module, as any of the functional attachment modules shown in Figures 1A-1C and 5A, or as a separate functional attachment module that serves as an adapter between the automated guided vehicle and at least one of these other types of functional attachment modules.

[0102] FIG. 5D is a rear view of an automated guided vehicle 512 docked to a base 522 as shown in FIG. 5C or 5D, with the surfaces of the base and the automated guided vehicle contacting a lower support surface S at multiple points 524a. Figure 5E is a rear view of the docked automated guided vehicle 512 of Figure 5D after the first drive system of the automated guided vehicle, which includes a front and rear pair of gear wheels, e.g., wheels 526a, 526b, has been actuated by rotation of gear wheel 520 in the direction of the arrow to lift the base to which the automated guided vehicle 512 is docked so that none of the surfaces of the base, including surface areas 524a, 524d, come into contact with the lower support surface S. Base 514 includes an internal jack mechanism that includes linearly extendable legs 528a, 528b that move downward when gear wheel 520 rotates and drives one or more gears of the drive mechanism, such as gear 515.

[0103] FIG. 6A is a perspective view showing the post-merge alignment of the automated guided vehicle 612, and the third base 614 may be implemented as an integral part of the functional accessory module, as one or more of the functional accessory modules shown in FIGS. 1A-1C and 5A, or as an auxiliary functional accessory module sized and configured to act as an adapter between the automated guided vehicle and at least one of these other types of functional accessory modules. Base 614 is a supplemental functional attachment module that is sized and configured to allow automated guided vehicle 612 to enter, lift, and transport functional attachment module 618 (FIG. 6C).

[0104] To accommodate the entry of the automated guided vehicle 612, the base 614 of the auxiliary adapter defines a central entry opening having side recesses 615a, 615b. As shown in FIG. 6B, which is a rear view of the combined automated guided vehicles of FIG. 6A, the side recesses 615a, 615b are aligned with their corresponding track segments 616a, 616b, respectively. The track segments 616a, 616b are attached to the inner surface of the base 614 and are aligned with one another such that both track segments 616a, 616b are vertically oriented when the bottom surface 617 of the auxiliary adapter rests on a generally horizontal lower support surface.

[0105] To accommodate docking with any of the above functional accessory modules, the automated guided vehicle 612 may use gear wheels and axles that are brought closer together by an appropriate mechanism (not shown). In other embodiments, the distance between the gear wheels 620a, 620b remains fixed during all inventory control tasks, including vehicle alignment, entry into the functional attachment module, and all stages of the process of docking with the functional attachment module. Thus, a high degree of alignment must be maintained between the gear wheels of the automated guided vehicle 612, on the one hand, and the track segments 615a, 615b of the automated guided vehicle's base, on the other hand.

[0106] To this end, the function-attached module may include a releasable interlocking structure, such as, for example, a protrusion (not shown). For example, the auxiliary functional accessory module of Figures 6A and 6B may include a recess extending downward from the bottom surface 617, and one or more drive systems of the automated guided vehicle 612 may be actuated to lower a protrusion into and lift the protrusion out of a dimensioned recess, for example, drilled, in the lower support surface S. Such an arrangement may be reversed, such that a recess is provided in the bottom surface 617 and a protrusion is attached, secured or formed to protrude upwardly from the lower support surface S.

[0107] The releasable engagement between the convex and concave portions as described above is one way of maintaining the position of the base 614 against undesirable lateral displacement that may occur due to unexpected impact forces during the docking process, for example, when the automated guided vehicle and functional accessory module decelerate. Improper alignment of the gear wheels of the automated guided vehicle 612 and the functional attachment module when docking is one cause of potential collisions. In this regard, sensors on the automated guided vehicle 612 may be used to initiate a realignment where the automated guided vehicle 612 backs up, makes a small angle adjustment, and attempts to re-enter the base 614 . Meanwhile, the automated guided vehicle is configured with an alignment system that facilitates proper alignment of the gear wheels 620a-620c of the automated guided vehicle 612 with these functionally attached modular structures, e.g., base 614, using track segments.

[0108] The use of an alignment system minimizes the chance of damaging either of the two structures (gear wheel and track segment) during the docking process. In Figures 6A and 6B, the alignment system includes parallel, floor-mounted guide rails 632,634. Rails 632 , 634 are separated by a gap sized to receive and guide linear translational movement of a support depending downwardly from automated guided vehicle 612 . That is, the rails 632, 634 are spaced apart along their lengths by a gap wide enough to accommodate the entry and passage of a series of guide members 633. Each guide member 633 is suspended from the undercarriage of the automated guided vehicle 612 by a rod 635 (FIG. 6B).

[0109] 2C-2F, the automated guided vehicle 200 also includes a guide member 233. In FIG. 2C, the guide members are arranged along the longitudinal centerline L. The guide member 233 is positioned along the underside of the automated guided vehicle 612, as shown for the guide member 233 in FIG. 2C. When all guide members 633 enter the gap between rails 632, 634, proper alignment can be maintained between the automated guided vehicle 612 and base 614 (or any other member of the functional accessory module and storage structure). It should be noted that the gap between rails 632, 634 may taper from a larger width dimension (at the entry point of the leading guide portion) to a smaller width dimension, thereby easing the strain on the automated guided vehicle 612 which begins docking with the same tight dimensional tolerances required at the entry point at base 614, which is, for example, the auxiliary adapter's functional attachment module itself. The taper may be monotonic in the entry transition zone. That is, the gap portion may decrease in width at a constant rate in the direction of vehicle movement toward the functionally attached module with which the automated guided vehicle is docking, and thereafter the gap portion between the rails may maintain a constant width selected so that the alignment of the automated guided vehicle with its entry point into the functionally attached module is sufficiently accurate. If the automated guided vehicle is equipped with a gear wheel, such as automated guided vehicle 212, 612, such alignment is determined by the spacing of corresponding teeth on the guide members or jack systems of the functional attachment modules with which the gear wheels interact.

[0110] Once the automated guided vehicle 612 is moved into proper alignment with the base 614, one or more drive systems of the automated guided vehicle 612 are operated so that its wheels, including omnidirectional wheels 654a (FIG. 6A) 656a, 656b (FIG. 6B), move the automated guided vehicle 612 into the base 614. A motor (not shown) of a first drive system of the automated guided vehicle rotates gear wheels 620a and 620b in the directions of the arrows shown. For example, rotation of the gear wheel with the teeth of rack segments 616a, 616b urges base 614 in the direction of arrow F, which is upward. The automated guided vehicle 612 lifts the base 614 to which it is attached so that the bottom surface 617 of the base 614 is no longer in contact with the lower support surface S.

[0111] FIG. 6C is a perspective view of inventory control system 600 illustrating the placement and use of multiple function attachment modules 618 shown in FIGS. 5A-6B. In this case, the automated guided vehicle 612 is shown disposed within a base that is formed as an integral part of each functional attachment module 618 . Each functional accessory module 618 includes a plurality of containers, e.g., containers 618a, 618b, arranged along a stalk 619 so that they are at an appropriate height above the underlying ground for a human operator H to retrieve items from nearby storage racks and place them into one of the containers. Thereafter, operator H may confirm the conclusion of the processing completion by inputting data via a touch screen panel, for example touch screen terminal 621. In this example, a second operator located at the picking destination retrieves items from bins 618c and 618d and places them into carton C for shipping.

[0112] 7A-7D, FIG. 7A is a perspective view showing the pre-merge alignment of the automated guided vehicle 712, and it can be seen that the first functional attachment module 714 has the form of an auxiliary adapter functional attachment module between the automated guided vehicle 712 and at least one of the other types of functional modules shown in FIGS. 1A-1C. As with Figures 6A and 6B, the embodiment of Figures 7A and 7B may employ a releasable interlock system and alignment system, both not shown, to facilitate the required docking between the automated guided vehicle 712 and the auxiliary function accessory module 714. To assist the auxiliary function attachment module 714 in its function of lifting the dynamically positionable function attachment module structure (function attachment module 718 of Figures 8A-8C), the upper surface of the function attachment module 714 may also include a plurality of upwardly extending mating protrusions 715. The protrusions 715 are sized and configured to align with their corresponding structures, such as the recesses 723 of the auxiliary function attachment module 718 of Figures 8A-8C, during the docking process. When docked, while being transported across the lower support surface S by the automated guided vehicle 712, the protrusion 715 of the function-attached module 714 forms part of a releasable interlock with any auxiliary function-attached module structure.

[0113] FIG. 7B is a perspective view illustrating post-merge alignment between the semi-autonomous automated guided vehicle 712 and the functional attachment module of FIG. 7A. Figure 7C is a rear view of the combined automated guided vehicle 712 and first functional attachment module 714 of Figure 7B, with the respective faces of the automated guided vehicle and first functional attachment module in contact with the lower support surface S at points 724a, 724b, 724c, and 724d. Figure 7D is a rear view of the combined automated guided vehicle 712 and first functional attachment module 714 of Figure 7B after the first drive system of the automated guided vehicle, which includes gear wheels 720a and 720b, has been activated to lift the first functional attachment module 714 so that none of its surfaces, including surfaces 724a and 724d, contact the underlying support surface.

[0114] Referring now to Figures 8A-8C, Figure 8A is a partial front view showing the pre-merge alignment of the mating automated guided vehicle 712 and the first or auxiliary functional accessory module 714 of Figure 7D, which includes a second functional accessory module 718, which is implemented as a multi-level storage rack having storage shelves 719. The storage shelf 719 of the second functional accessory module 718 defines its corresponding storage surface 719a, which contains items, such as the inventory container C shown in Figures 8A and 8B and / or individually boxed inventory items placed directly on the storage surface 719a shown in Figure 8C. The second function attachment module 718 also defines floor contacting surfaces 724e, 724f that are sized and configured to support the storage rack on an underlying support surface.

[0115] Figure 8B is a partial front view showing the docking of the automated guided vehicle 712 and the post-docking alignment of the first functional attachment module or auxiliary functional attachment module 714 of Figures 7D and 8A, after the first drive system of the automated guided vehicle, which includes a second functional attachment module 718 and is equipped with gear wheels 720a, 720b, has been activated to further lift the first functional attachment module 714 and also lift the second functional attachment module 718 so that neither the surface of the first functional attachment module nor the second functional attachment module 718 contacts the lower support surface S. Figure 8C is an overall front view showing the relative positions of the combined automated guided vehicle, first function attachment module 714 and second function attachment module 718 after the second function attachment module 718 has been lifted and transported to another location as shown in Figure 8B.

[0116] The second function attachment module 718 may need to support and store a collection of heavy items, such as the second function attachment module 718 and the items stored therein, with a total weight approaching 400 kg or more, as shown in FIG. 8C. Here, the inventors have discovered that additional contact force supplied to a non-omnidirectional drive member can improve the maneuverability of an automated guided vehicle transporting a functional attachment module carrying a heavy payload. 4D-4G, the automated guided vehicle 200 or the automated guided vehicle 712 includes a power applying member 402. The force applying members 402 are selectively movable from a first or initial position (FIG. 4D) in which each force applying member 402 applies no force to the drive member of its corresponding automated guided vehicle 200 or automated guided vehicle 712 . The power imparting members 402 are actuated from their initial position to a second position (FIG. 4E). The force imparting members 402 are rollers that are freely rotatable within a carrier 406 about their own axes of rotation. As shown in Figures 4E and 4G, when each roller 402 is moved to its respective second position, it exerts a force normal to the face of the drive member on which it rests. On the other hand, applying this normal force increases the frictional contact between the drive member and the lower support surface.

[0117] As shown in Figure 4E, sufficient force F N is applied, lifting the omni-directional wheels, resulting in a gap g between each wheel and the lower support surface S. w occurs. In practice, while the automated guided vehicle 200 is transporting the function attachment module 718, the gap g w is variable and will be different between each of the omni-directional wheels at any given time. That is, the equal gap g between the front and rear omnidirectional wheels in FIG. 4E w The appearance of, for example, suggests a perfectly balanced load and is only a temporary condition.

[0118] In particular, if a functional accessory module carrying large or heavy items, such as functional accessory module 718, is not used in performing inventory control tasks, then automated guided vehicle 712 need not include power imparting member 402 or similar structure that increases frictional contact with the underlying support surface. A configuration such as that shown in FIG. 1C may omit the function attachment module 718 entirely. On the other hand, the automated guided vehicle 712 includes a power imparting member 402, and a first on-board motor is used to independently rotate one of the central drive members, while a second on-board motor is used to independently rotate the other of the central drive members. The orientation can then be changed in any direction by rotating the central drive members in opposite directions, or in the case of a larger radius of rotation, by rotating one in the same direction but at a higher speed than the other. Additionally, the omni-directional wheels on one side, eg, wheels 754b and 756b, may be driven by the same on-board motor or motors used to drive the central drive member on that side. Additionally, for vehicle 200, a single third on-board motor may be used to drive all of the omni-directional wheels as described above. In any of the above examples, the loading and unloading mechanism may be driven by a separate on-board motor, thereby eliminating the need for a clutch mechanism.

[0119] FIG. 9 is a partial perspective view showing elements of an inventory control system 900 including a first group of function-associated modules 714 and a second group of function-associated modules 718 configured to cooperate with the automated guided vehicle 712 to perform a corresponding subset of inventory control tasks, and a third group of function-associated modules 918 configured to cooperate with the automated guided vehicle 712 to perform a further subset of inventory control tasks. In particular, as described below with reference to Figures 10A and 10B, the automated guided vehicle 712 is further dimensioned and configured to enter, lift, transport, and move vertically within a task completion zone Z defined by adjacent pairs of columns 929a, 929b of functional attachment modules 918.

[0120] Within task completion zone Z, the automated guided vehicle 712 can be configured to lift by operation of its drive system in cooperation with the guidance system of the functional attachment module 918 to transport individual inventory items or, alternatively, containers, cases, cartons and / or pallets supporting multiple inventory items. By operation of a transfer mechanism, e.g., individual drive rollers, e.g., rollers 711 of an automated guided vehicle 712, such one or more items are transferred to a storage area of a multi-level flow rack structure 920 located adjacent to a destination area including a picking station PS. As shown in FIG. 10B, the guide system includes track segments 926 fixed to, attached to, or formed on the inwardly facing surfaces of rows 929a, 929b.

[0121] At a location closest to the picking station PS, a flow rack structure, e.g., flow rack 920, can supply one or more operators with those inventory items that are needed or are expected to be needed based on a demand forecast to fulfill inventory control requests in an upcoming inventory control interval (e.g., to fulfill e-commerce or mail order orders during one or more upcoming picking cycles). Such a rack structure may be provided by dynamically movable (and removable) function attachment modules 918 shown in Figures 9 and 10A-10F. Additionally or alternatively, the functional attachment modules 918 may be permanently attached to one or more flow racks 920, such that an automated guided vehicle, e.g., automated guided vehicle 712, may use the already-existing functional attachment modules to perform assigned inventory management tasks, e.g., transporting items to the delivery zone of the flow racks 920.

[0122] When not needed for other inventory management tasks or while flow racks 920 are being replenished at a high rate, a subset of the total number of automated guided vehicles 712 deployed at a given facility may be reserved for use in one or more of the task activity zones Z of their corresponding functional accessory modules 918. During such periods, replenishment of items into the storage zone of the flow rack 920 may be accomplished by actuating the transfer mechanism (e.g., rollers 711) of the arriving vehicle 718 to shift items from the arriving vehicle to an automated guided vehicle 718 already positioned within the task activity zone of the functional attachment module 918. Coordination of movements between arriving automated guided vehicles and "local" transfer vehicles may be by peer-to-peer communication between the automated guided vehicles or may be performed by a central controller.

[0123] The automated guided vehicles and functional accessory modules may be used with a variety of flow racks 920 . The flow rack may be gravity assisted only and may feed items to the picking station PS using unpowered rollers for unidirectional feeding. Alternatively, as shown in FIG. 9, the flow rack 920 may use a bidirectional network of parallel belts 932, or one or more other conveying members, to advance items toward or away from the picking station PS. Then, to supply items to be transported to a picking station by one of the automated guided vehicles 718, one or more of the belts 932 must be driven in a first direction, away from the automated guided vehicle and toward one or more picking stations.

[0124] Conversely, removing an item from flow rack 920 requires a reversal of the process described above from automated guided vehicle to rack structure. Such reversals may be permitted, for example, when a different subset of items is to be stored in flow rack 920 in preparation for a new item picking cycle. Additionally or alternatively, items currently stored on the surface of belt 920 may no longer be needed in the same picking quantities as before during the current and near future picking cycles. In this case, relocation of items between an area reserved for high-movement inventory items and a remote area suitable for low-movement inventory items, as illustrated by the arrangement of flow rack 920 in FIG. 9, may be advantageous to keep the average travel time per picker acceptably low. For example, during off-peak hours, when fewer carriers are available to retrieve items to be picked from remote areas, increased efficiency can be achieved by using automated guided vehicles 718 to temporarily move slow-moving items to rack structure 920. In such a configuration, the intermediary accesses these items during one or more off-peak inventory intervals. For example, low turnover items may be returned to a remote storage zone in preparation for the next interval when there are more agents available to pick and place.

[0125] The vehicle 718 includes a loading / unloading assist member (not shown) that operates in cooperation with the automated guided vehicle's transfer mechanism to align items being transferred from the automated guided vehicle with target areas of the rack structure 920. To transfer an item from one of the automated guided vehicles 718 to a particular subset of belts 932 of the flow rack 920, the automated guided vehicle's control device is configured to operate the loading / unloading assist members to urge the item to move laterally relative to the direction in which the automated guided vehicle's loading / unloading mechanism advances the item toward the subset of belts 932, thereby achieving and maintaining the required alignment. As an example, the loading / unloading assistance member includes a pusher bar (not shown) sized and configured to protrude from one of the two side wall portions of the automated guided vehicle 718 above the support plane defined by the highest surface of the roller 711.

[0126] As an extension of dynamic inventory placement using automated guided vehicles and functional attachment modules, and referring to FIG. 9, other inventory items may be stored on shelves in that first subset of functional attachment modules 718, shown at 718a, closest to the picking station. Items that are needed less frequently than those stored in functional attachment modules 718a and / or flow racks 920, but that will need to be accessed at some point during the current or near future inventory management cycle, may be stored in a second subset of functional attachment modules 718, shown as 718b, somewhat further from picking station PS. Yet another subset (not shown) of functional attachment modules 718 used to store items not needed during the current or near future inventory control cycle may be located further away than subsets of functional attachment modules 718a, 718b.

[0127] Also shown in Figure 9 is a further automated guided vehicle 712 that moves container C1 directly from the picking station operator, before the contents of container C1 are retrieved and transferred to one of the shipping cartons C2, which are moved by discharge conveyors 922, 924, respectively. The carton C1 is maneuvered into position below the work surface WS in front of the operator and then lifted by the automated guided vehicle 712. For this purpose, aligned, inwardly facing track segments (not shown) are provided, and when the gear wheel rotates in a first direction, the automated guided vehicle moves in and upwards, thereby moving carton C1 to the position shown in front of the operator. Once the desired quantity of one or more items has been collected from carton C1, the gear wheels of the automated guided vehicle are operated in the opposite direction, causing the automated guided vehicle to lower so that the automated guided vehicle can be used for the next scheduled inventory control task assigned to it.

[0128] Suffice it to say that the use of automated guided vehicles and functional attachment modules allows for a variety of stock storage configurations and their inventory to be dynamically utilized and rearranged throughout each stock management window. This applies whether the window spans the entire inventory management cycle (which could be anywhere from 6 hours to the full 24 hours, including picking and replenishment activities), or whether the window is subdivided into multiple intervals to better accommodate fluctuations in both demand for specific inventory items and the availability of manpower resources to handle them. These same automated guided vehicles may also retrieve and return items from stationary located storage areas, further increasing the efficiency of the warehouse facility throughout the inventory control cycle.

[0129] Figures 10A and 10B are front views showing alignment during docking between the automated guided vehicle 712 and one of the functional attachment modules 918 before activation of the first drive system, which in Figures 10A and 10B includes gear wheels 720a, 720b. For example, to maintain the function attachment module 918 in an aligned position with the flow rack shown in FIG. 9 and shown in FIG. 10B, the function attachment module 918 includes upper and lower docking clips 927a and 927b, respectively. When the function attachment module 918 is aligned with the rack structure, the function attachment module 918 is lowered by the automated guided vehicle 712 to a position where the mating clips engage with their corresponding clips fixed or formed on the flow rack.

[0130] 10C is a partial front view taken from the perspective of FIG. 10A, showing a rotating member of the first drive system, e.g., gear wheel 720b, aligned opposite its corresponding portion of the guide system of function attachment module 918. In this case, the guidance system of the functional attachment module 918 includes inwardly facing tracks, such as track 926 . When the automated guided vehicle 712 enters the interior space defined between the vertical rows 929 of functional attachment modules 918, the gear wheels of the automated guided vehicle rotate so that the drive system wheels engage with the guide system of the functional attachment modules 918, which has a pair of inwardly facing tracks 926 that engage with the gear wheels 720a, 720b. Rotation in one direction lifts the function-attached module 918 above an underlying support surface, allowing the function-attached module to be transported by the automated guided vehicle 712 . Once the aligned position is achieved, the gear wheel of the automated guided vehicle 712 is rotated in the other direction, lowering the function attachment module 918 to the lower support surface. In this process, the upper and lower docking clips 927a and 927b are engaged. The lifting of the function attachment module 918 by the automated guided vehicle 712 for transport is shown in Figures 10C-10E.

[0131] As can be seen with reference to Figures 10A and 10B, the process of the automated guided vehicle 712 aligning with and entering the functional attachment module 918 may occur regardless of whether the functional attachment module 918 is already involved in transporting an item to the destination area. A feature of the present disclosure is that in a first mode of operation, each automated guided vehicle is configured to complete some or all of its assigned inventory control tasks without the use of functional accessory modules, such as retrieving an item C from a storage area 110 in the vertical array of such storage areas shown in FIG. 1C , transferring an item C from one storage area 110 to a different storage area 110, delivering an item, e.g., a container C, to a picking station, or any combination thereof. For example, in Figures 9 and 10A-12, in the second operating mode, the same automated guided vehicle is also configured to complete other tasks by acquiring and using functional accessory modules to complete additional inventory management tasks. Figures 10C to 10E show that, for example, in the second operating mode, the automated guided vehicle 712 is configured to enter the functional attachment module 918, lift the functional attachment module while carrying a container, move the functional attachment module 918 horizontally to a different position, and lower the functional attachment module at this different position. As shown in FIG. 10F, the automated guided vehicle 712 is further configured to ascend within functional accessory modules that assist with inventory control tasks.

[0132] Figure 10D is an enlarged partial front view taken from the same perspective as Figures 10A and 10C, after each rotating member of the first drive system of the vehicle 712, e.g., gear wheels 720a, 720b, has been actuated in a first direction, along with its corresponding opposing track portion 926 of the guide system of the functional attachment module 918, which serves to lift the functional attachment module 918 above the surface as shown in Figure 10D. Figure 10E is a front view from the same perspective as Figure 10B, after the rotating member of the first drive system has been actuated in a first direction to lift it, along with its corresponding opposing part of the guide system of the functional accessory module. Figure 10F is a front view from the same perspective as Figures 10B and 10E, showing each rotating member of the first drive system of the automated guided vehicle, together with its corresponding opposing portion 926 of the guide system of the functional attachment module, after the functional attachment module has been set on a lower support surface as shown, and then actuated in a second direction to raise the automated guided vehicle 712 within the functional attachment module 918.

[0133] FIG. 11A is a rear perspective view showing the arrangement of a functional attachment module, such as the functional attachment module 918 shown in FIGS. 10A-10F, in which a flow rack 1120 is sized and configured to supply items, such as high-turnover merchandise (not shown), in a goods-to-picker inventory management system 1100. 10A-10F, the dynamically positionable function attachment module 918 may include docking clips or retaining clips, such as upper docking clip 927a and lower docking clip 927b, respectively. FIG. 11B is a side view of FIG. 11A, showing the function attachment module 918 just before it is docked with the flow rack 1120. FIG. The flow rack 1120 includes corresponding pairs of upper and lower merged clips 1027a and 1027b that are sized and configured to receive and retain portions of the upper and lower merged clips 927a and 927b.

[0134] To interlock and align the respective pairs of upper and lower mating clips 1027a and 1027b, the first drive system and / or the second drive system of the automated guided vehicle 712 are operated to move the function attachment module 918 horizontally in the direction of the arrow. As shown in FIG. 11A, when the two structures are close to each other, the gear wheels of the automated guided vehicle 712 are driven in the opposite direction to that required to lift the functional attachment module 918, while the functional attachment module 918 moves in the direction of the vertical arrow. This rotation continues until the face of the function attachment module 918 is supported by the lower support surface. The resulting interlock between the complementary pair of mating clips secures the function attachment module 918 to the flow rack 920 in the position shown in FIG. 11A. However, other mechanisms may be used to releasably interlock the function attachment module 918 and the flow rack 1120.

[0135] As described above, the structures that perform the functions of the functional attachment module 918 may be integrally formed as part of the flow rack 1120 or may be attached to the flow rack 1120 using fasteners, clamps, etc. so that coupling / uncoupling and separation are not achieved by the coordinated movement of the automated guided vehicle 712. Suffice it to say that any such rack structure need only define a task activity zone into which an automated guided vehicle, e.g., automated guided vehicle 712, can enter, lift, align with the storage surface, and exchange items between the surface of the rack structure and the transfer platform of the automated guided vehicle.

[0136] 11C, a side view of FIGS. 11A and 11B is shown after the functional attachment module 918 has docked with the flow rack 1120 and elevated the automated guided vehicle 712 within task activity zone Z. As shown, the rack structure includes three storage tiers of storage locations generally designated 1102, 1104, and 1106, respectively. The automated guided vehicle 712 is shown to have achieved vertical ascent within the task activity zone Z of the functional accessory module 918, aligned with the highest storage level 1106, and the automated guided vehicle's rollers 711 have already been activated to advance the container C to the target surface of the flow rack 1120.

[0137] For example, the clutch mechanism used in the automated guided vehicle 200 shown in FIGS. 2A to 2I may be omitted. The first motor is used to independently rotate one of the central drive members, e.g., drive member 752b, while the second motor is used to independently rotate the other of the central drive members. Any change in orientation is achieved by rotating the central drive members in opposite directions, or for larger turning radii, in the same direction but rotating one faster than the other. Additionally, the omni-directional wheels on one side, eg, wheels 754b and 756b, may be driven by the same on-board motor or motors used to drive the central drive member on that side. A single third motor may be used to drive all of the omni-directional wheels as described above for automated guided vehicle 200. In any of the above examples, or others, the loading and unloading mechanism may be driven by a separate on-board motor, thereby eliminating the need for a clutch mechanism.

[0138] The automated guided vehicle 712 in the inventory management system 1100 includes the features of the automated guided vehicle 200, such as the second drive system with a clutch mechanism (FIGS. 3A to 4C) and the transfer mechanism (FIGS. 2D to 2I). The onboard motor (not shown) of the automated guided vehicle 712 is operated to lift the automated guided vehicle 712 within the activity zone Z. The gear wheels of the automated guided vehicle 712 rotate by meshing with the teeth of the track 926 . As a result, the front omni-directional wheel, eg, wheel 754b, and the rear omni-directional wheel, eg, wheel 756b, remain at their respective support positions on the lower support surface. Additionally, a rotatable carriage (not shown), of which only the second drive member 752b is shown, drops the second drive member while simultaneously engaging one or more clutch mechanisms (not shown). On the other hand, engagement of the clutch mechanism allows rotation of sprocket 717b. One or more additional motors rotate to drive the endless carrier 714 b and the loading mechanism advances the container C onto the face 1106 of the storage structure 1120 .

[0139] Referring to FIG. 11C, it should be noted that if the pitch angle of the storage tier is sufficient, the container C may be advanced by gravity alone, for example, by a passive roller or chute arrangement. In contrast, in Figures 11D-11G, the multi-level flow rack 1120 of the inventory management system 1100 includes loading and unloading aids at each level. As described above with respect to FIG. 9, the loading and unloading assistance member includes a plurality of parallel belts 1128 and, optionally, a sensor for determining when to advance inventory items placed by an automated guided vehicle, such as automated guided vehicle 712, toward the end closest to one or more pickers.

[0140] FIG. 11D is a perspective view of FIGS. 11A to 11C, showing the automatic guided vehicle in the function attachment module rising to the position shown in FIG. 11C. FIG. 11E is a top view of the inventory management system 1100 of FIGS. 11A-11D illustrating the elevation of the automated guided vehicle 712 within the task activity zone of the functional attachment module 918. 11F is an enlarged partial plan view of FIGS. 11A-11E after the transfer of container C1 from the transfer platform of the elevated automated guided vehicle 712 to the target surface 1106f of the flow rack 1120. FIG.

[0141] As an example, inventory management system 1100 is deployed at an order fulfillment facility in an e-commerce application. Vehicle 712 supplies containers, eg, containers C1 and C2, which may contain multiple individual inventory items. The warehouse management system at this facility is generally S1 ,I S2 ,I S3 ,I S4 ,I S5 ,I S6 The flow rack 1120 has determined that a sufficient quantity of a subset of inventory items, designated by , is required to be continuously present in the flow rack 1120 during the current or near future inventory interval. Dynamic placement of inventory items using automated guided vehicles and functional attachment modules, such as functional attachment module 918, can reduce the time required to retrieve items and package those items for shipping as part of an e-commerce operation. As an example, a human operator travels between a packing station and item transfer area A near a flow rack 1120 that separates the human operator from an automated guided vehicle 712 operating in item transfer area B.

[0142] Referring to Figures 11E and 11F, it can be seen that the automated guided vehicle 712 has stopped ascending within the task management zone of the functional attachment module 918a and is stopped at a transfer position relative to multiple third stage positions, also collectively identified in Figures 11C and 11D by reference numeral 1106 and generally designated 1106a-1106g.

[0143] Item Subset I S1 ~I S5 and the contents of container C1 and storage area 1100g, there is a continuing need for sufficient quantities of these containers in flow rack 1120 relative to other items processed by the facility during the current or near future inventory control interval. In this example, the warehouse management system has determined that other items stored in flow rack 1120, such as those stored in container C2 at location 1106f for retrieval earlier in the current inventory control interval (and / or during the interval before that), no longer have sufficient priority or no priority at all for the same amount of inventory to be in flow rack 1120. The same automated guided vehicle 712 and functional attachment module 918a or a different automated guided vehicle and functional attachment module pair may be used to exchange container C2 for a different container. The sequence of such an exchange operation will be described with reference to FIGS. 11G to 11I.

[0144] FIG. 11G is a top view of FIGS. 11A-11F illustrating the temporary placement of function-attached module 918a in an interlocking aligned position with storage location 1106f of flow rack 1120. FIG. While in this position, the automated guided vehicle 712a ascends within the task activity zone of functional attachment module 918a and retrieves container C2 as described above, after which the automated guided vehicle 712a returns to the underlying surface. Further movement of the gear wheel causes function attachment module 918a to be lifted from the underlying support surface, causing automated guided vehicle 712a to reposition function attachment module 918a to the solid line position shown in FIG. 11G. In FIG. 11G, the movement of automated guided vehicle 712a and the movements of automated guided vehicles 712b to 712d shown in FIG. 11G are guided by a grid of alignment markers shown at 1132 that are detected by one or more imaging sensors (e.g., cameras) on each automated guided vehicle (not shown). However, other position tracking systems and techniques may be used.

[0145] The automated guided vehicle 712 uses a capacitor that needs to be periodically charged. While the automated guided vehicle returns to a charging station spaced from the flow rack 1120, in other embodiments, an electrical charging port (not shown) is present at a predetermined location near the track structure so that the automated guided vehicle 712a does not need to exit the task activity zone of the functional accessory module 918a. 11H and 11I are rear elevational views of flow rack 1120 of inventory control system 1100 after the transfer of item C2 from automated guided vehicle 712a to automated guided vehicle 712b, as described above. In this example, automated guided vehicles 712a and 712b each return to a charging station to restore power before being assigned further inventory control tasks. Thus, Figure 11H shows automated guided vehicle 712c entering function attachment module 918a, while Figure 11I shows automated guided vehicle 712c lifting item C3 within the task management zone of function attachment module 918a, whereupon the transfer of item C3 to storage area 1106e (Figure 11G) is completed by operation of the transfer mechanism of automated guided vehicle 712c.

[0146] FIG. 12 is a partial perspective view of a portion of an inventory control system 1200 that may form part of the system shown in FIG. 1C and that uses automated guided vehicles 1212 to transport containers 1202 of inventory items back and forth between a picking area and a vertical array of storage locations 1220. The material handling system includes all of the elements of system 900 shown in FIG. 9, but further uses automated guided vehicles 1212 and an array of storage locations 1220 as elements of an automated storage and retrieval system. When dynamically deployable functionally attached modular structures 718a, 718b are used along a structure that defines a vertical array of storage locations 1220, the automated guided vehicle 1212 may be configured like the automated guided vehicle 200, automated guided vehicle 712 described above. On the other hand, if such compatibility is not required, for example, when relying on flow racks 1120 and storage locations 1220, these features of an automated guided vehicle configured to maintain maneuverability under heavy loads need not be included.

[0147] 13A-13E, the process of storing and retrieving items within an array of storage locations, such as location 1220 in FIG. 12, will now be described in detail. Referring first to FIG. 13A, a front elevational view is shown illustrating a plurality of automated guided vehicles 1212a-1212e operating within or near a rack structure 1300. As in the above embodiment, the automated guided vehicles perform various item replenishment and / or item retrieval tasks, including retrieving containers from and returning containers (or totes) to storage locations 1315a, 1315b, 1315c, 1315d.

[0148] As shown in Figures 13A and 13B, automated guided vehicles 1212b, 1212d are shown supported by lower support surfaces when operating within areas Z1, Z2 directly below the storage locations. Areas Z1 and Z2 are operational zones that allow automated guided vehicles to conveniently enter and exit the rack structure 1300. For example, in FIG. 13A, automated guided vehicle 1212a is shown entering rack structure 1300 and passing under support surface 1322 of a first vertical array of storage locations. The support surfaces 1320, 1322 are defined in this example by shelf channels that are supported by multiple vertical rows of support rows 1304a, 1306a, 1308a, 1310a shown in Figure 13A. The automated guided vehicle 1212b is shown to have made a rotation of 90 to 270 degrees in order to continue moving over the substantially horizontal lower support surface of the substrate manipulation zone Z1. Meanwhile, automated guided vehicle 1212c is entering the queue in which it is ascending. Automated guided vehicle 1212c ascends, as does automated guided vehicle 1212e, which has already ascended in the drive train behind the drive train occupied by automated guided vehicle 1212c. In particular, each of the automated guided vehicles 1212a, 1212e moves within a respective drive train by actuation of a drive system, which may include a gear wheel having teeth for engaging complementary teeth defined by inwardly facing track sections formed along the four support rows. For example, automated guided vehicle 1212d is shown entering zone Z2 from a location external to rack structure 1300 and moving along underlying zone Z2 on the lower support surface or about to exit.

[0149] FIG. 13B shows a multi-container or tote T a ,T b ,T c ,T d 12. A side view of a rack structure 1300 provided with totes containing items, e.g., as part of the inventory management system 1200 of FIG. 12, in which a plurality of automated guided vehicles operate to perform various item replenishment and / or item retrieval tasks. Again, tote 1212a is shown passing through operating zone Z1 and entering the leftmost drive train, designated D1. Referring now to FIG. 13C, a rack structure 1300 may include an array of parallel guide rails, e.g., rails R1 and R2, with a gap g therebetween. G It can be seen that the following is defined. The gaps are sized and configured to accommodate the corresponding alignment structures of the automated guided vehicles, allowing the automated guided vehicles to enter, exit and change course without damaging each other or the rack structure. Such rack structures are omitted here from the details of the automated guided vehicle 200. Suffice it to say that when such structures are provided on an automated guided vehicle, additional alignment structures including one or more gaps may be included to guide the automated guided vehicle. For example, as shown in FIG. 13C, the alignment system 1350 on the second floor includes a circular, plate-like member with an orthogonal gap pattern. The automated guided vehicle 1212b uses the positioning system 1350 to change course angle, for example, in preparation for making a right turn to travel within substrate zone Z2.

[0150] As an additional alignment structure, a gap g G The third floor may include an alignment system 1340 consisting of a pair of plate members spaced apart by a gap. The gaps defined by alignment system 1340 are aligned with the gaps defined by alignment system 1350 to allow the automated guided vehicles to quickly and easily traverse the entire width of the structure from operation zone Z1 to substrate zone Z2 while preventing angular changes in path within drive trains D1 through D6.

[0151] As described above, the rack structure 1300 is sized and configured to allow automated guided vehicles to enter and exit at various positions below the storage locations, thereby allowing for flexibility in the placement of picking and / or replenishment stations. With particular reference to Figures 13D and 13E, the rack structure 1300 may employ a network of reduced cross-section supports, generally designated 1370, for supporting the storage locations, e.g., support rows 1304a, 1306a, 1308a, 1310a of Figure 13A. The reduced cross-section support 1370 is telescopically received or attached by fasteners, welding, etc., at the desired location.

[0152] The retractable guide wheels may be omitted without damaging the automated guided vehicle. Referring to FIG. 13E, the guide system 1380 of the rack structure 1320 includes a transition zone 1380a having a special contour (relaxed tolerances). A guide system 1380 including a transition zone 1380a is provided on opposite sides of the support 1370, but not on the other two sides. Within the transition zone, gaps are formed between the teeth of the track, allowing the teeth of the gear wheel of the automated guided vehicle to rotate freely without damage. This guidance system configuration allows automated guided vehicles to move directly into drive trains without the need for close spacing between guide wheels 1320a, 1320b, and further allows automated guided vehicles to move vertically within directly adjacent trains, as best shown in FIG. 13B.

[0153] FIG. 14A is a block schematic diagram illustrating the allocation of functional accessory module-assisted inventory control tasks among multiple automated guided vehicles by a controller 1450. The controller 1450 configures the plurality of automated guided vehicles into respective groups of one or more automated guided vehicles. The first group of automated guided vehicles 1402-1 to 1402-n has no association with a function attachment module. As can be seen in Figures 1A-1C, 9 and 12, not all tasks require the use of a function attachment module. Additionally, after terminating its association with the functional accessory module, the automated guided vehicle may return to the charging station, during which time it may not be eligible to receive inventory control task assignments from the controller 1450 . The second group of automated guided vehicles 1404-1 to 1404-n may be associated with function attachment modules selected from a first category or group of function attachment modules and a second category or group of function attachment modules. As an example, function attachment module category 1 may include auxiliary adapters, such as function attachment module 714 described above, and function attachment module category 2 may include movable rack function attachment modules, such as those shown at 718 . The third group of automated guided vehicles 1406-1 to 1406-n may include an auxiliary function attachment module 614 and a function attachment module 618 for transporting containers. A fourth group of automated guided vehicles 1408-1-1408-2 may include a function attachment module 918 used to allocate inventory to (and optionally from) the flow rack modules, as shown in FIG. Finally, the controller 1450 also tracks the location of any currently unassigned function attachment modules.

[0154] FIG. 14B is a block diagram showing the subsystems of multiple automated guided vehicles 1412-1 to 1412-n. Each automated guided vehicle, for example 1412-1, includes a controller that includes a central processing unit (CPU) 103, a memory 105, and a communication interface 1407. The communication interface may comprise a wireless transceiver compliant with a corresponding wireless transmission protocol, e.g., IEEE 802.11, and the interface of the automated guided vehicle is used to communicate with other automated guided vehicles, e.g., in a peer-to-peer topology, or with a central control unit. In this case, the automated guided vehicles 1412-1 to 1412-n may include a position detection sensor 1413 and an object detection sensor 1415, and may use an interface to communicate detected information with a master control device, for example, the control device 1450 in FIG. 14A. The position sensor includes an on-board imaging sensor for determining when the automated guided vehicle passes an alignment marker located on the lower support surface. Alternatively, automated guided vehicles 1412-1 through 1412-n may use signal triangulation and / or any other conventional technique to determine their respective positions relative to one another or enable a controller to do so.

[0155] Referring to FIG. 14B, it can be seen that each automated guided vehicle, for example, automated guided vehicle 1412-1, includes a power source 1417, which may be a rechargeable power source, for example, consisting of an ultracapacitor, one or more batteries, or a combination thereof. In one or more embodiments, the power source drives a first motor 1419 of the first drive system 1409 . The first drive system 1409 may further include a gear wheel driven by the first motor and used to drive the vehicle vertically, for example, within the functional attachment module 918 or within the rack structure 1320 of the automated storage and retrieval system. In this example, the power supply 1417 also provides power to a second drive system 1411 , which includes a second motor 1421 and, optionally, a third motor 1423 .

[0156] CPU 1403 may comprise one or more commercially available microprocessors or microcontrollers to facilitate data processing and storage. Various support circuits facilitate the operation of the CPU 1403 and may include one or more clock circuits, power supplies, cache, input / output circuits, etc. The memory 1405 comprises at least one of read-only memory (ROM), random access memory (RAM), disk drive storage, optical storage, removable storage, and the like.

[0157] FIG. 14C is a block schematic diagram of a controller 1450 capable of responding to instructions received from a warehouse automation system 1440 to coordinate the assignment and execution of inventory control task activities, such as those assigned to automated guided vehicle task groups 1402-1, 1404-1, 1406-1, and 1408-1, by a plurality of automated guided vehicles and functional accessory modules. The control device 1450 includes a central processing unit (CPU) 1451, support circuits 1455, memory 1452, user interface components 1454 (which may include, for example, a display with a touch-sensitive screen or a separate keyboard), and a communication interface 1453. The server 1450 is equipped with one or more wireless transceivers that comply with a corresponding wireless transmission protocol, for example, IEEE 802.11.

[0158] CPU 1451 may comprise a commercially available microprocessor or microcontroller that facilitates data processing and storage. Various support circuits facilitate the operation of the CPU 1451 and include clock circuits, power supplies, cache, input / output circuits, etc. The memory 1452 comprises at least one of read-only memory (ROM), random access memory (RAM), disk drive storage, optical storage, removable storage, and the like. The memory 1452 includes an operating system 1456 and an inventory control application. The inventory management application includes a task agent manager module 1460 , an automated guided vehicle traffic management module 1470 , a condition / event monitoring module 1480 and a data repository 1490 .

[0159] The task intermediary manager module 1460 comprises an inventory control task processor 1461, a dynamic inventory slot analyzer 1462, a subtask sequence identifier 1463, a task priority manager 1464, an event notification detector 1465, a state transition detector 1466, an automated guided vehicle selector 1467, and a function attachment module selector 1468. The inventory control task processor 1461 processes inventory control task requests received from the warehouse automation system 1440 by executing instructions from the CPU 1451 . The list of subtasks associated with a received task request may include, for example, those subtasks listed in the table below.

[0160] [Table 1]

[0161] The dynamic inventory slot analyzer 1462 allocates inventory items to various storage areas based on available manpower resources, the distances between where these resources are located, their respective pools of storage locations, and the known or projected demand for the items in the current and next inventory interval (e.g., 60-120 minutes). The subtask sequence identifier allocates subtasks, including each inventory control task, between the automated guided vehicle and the functional attachment modules. As an example, a first automated guided vehicle may lack sufficient power resources to complete all subtask elements of the entire task. In such a case, the first automated guided vehicle is controlled by the control device to transfer the inventory item and / or functional accessory module to the second automated guided vehicle in a timely manner sufficient to allow the first automated guided vehicle to return to the charging station, charge, and return to the pool of task-eligible automated guided vehicles. To support such functionality, the task intermediary manager 1460 further includes an event notification detector 1465 that determines when a critical power level threshold is exceeded, and a state transition detector 1466 that determines when other automated guided vehicle and functional attached module assets return to a task-eligible state.

[0162] The automated guided vehicle and functional attachment module selectors, 1467 and 1468, respectively, use the available location, power and remaining subtask data to select appropriate use of automated guided vehicle and functional attachment module resources to complete subtasks that were left unfinished on another automated guided vehicle and, if possible, ensure that these tasks are assigned to automated guided vehicles and functional attachment modules that have the resources to complete the tasks. The selector of the automated guided vehicle and functional attachment module may depend on information received from the location analyzer 1475 and the priority monitor 1476 .

[0163] Traffic management of the automated guided vehicles is performed by a traffic management module 1470 of the controller 1450 . In such cases, position, velocity and direction data is collected by the controller at regular intervals. The position data is analyzed and a path segment selector 1474 selects a path for each automated guided vehicle in the next control interval to ensure there are no collisions with other automated guided vehicles, personnel, or fixed structures. Updated instructions corresponding to the route selection, including heading and direction, are transmitted by the controller back to the automated guided vehicle. On the other hand, in other embodiments, the automated guided vehicle relies only on the controller for destination and task assignment, not for relative positioning instructions; instead, the automated guided vehicle relies on its internal data collection and spatial analysis capabilities.

[0164] To support the above operations, the controller 1450 of FIG. 14C includes a data repository reflecting the latest updated locations of all inventory items for which the warehouse automation system has assigned management and allocation responsibility, as well as a map of the locations of functional accessory modules within the facility. Additionally, usage statistics are collected for all automated guided vehicles and functional attachment modules with moving parts to assist in scheduling preventative maintenance processes so that parts can be inspected, lubricated, and / or replaced at regular intervals.

[0165] From the above description, it can be seen that a first type of rack structure, within which an automated guided vehicle is configured to operate in a first mode of operation, defines a plurality of vertical arrays of storage locations separated by column aisles through which the automated guided vehicle ascends. Such a rack structure is shown in Figures 13A-13E, where the guidance system includes parallel tracks sized and configured to allow automated guided vehicles to enter the row ascending therein from the side of the row, rather than entering the row from the end of the corresponding aisle in which the row is located. That is, the automated guided vehicle is configured to move over a support surface portion directly below the storage position of the array, and the automated guided vehicle may enter any row ascending within it from a direction transverse to the longitudinal axis of the aisle of the row ascending within it. Thus, three or more automated guided vehicles can simultaneously enter and / or exit the same aisle with each of the queues ascending therein.

[0166] The depth of the space allocated to the storage locations, and therefore to the path along the lower support surface S of the automated guided vehicles entering and exiting the ascending queue therein, is long enough to allow two automated guided vehicles to rotate and travel along the path parallel to each other.

[0167] A second type of rack structure, within which the automated guided vehicle is configured to operate according to the first mode of operation, defines a plurality of supply flow surfaces defined by the paths of ascending columns therein, with the parallel tracks of the guidance system being vertically oriented. Such an embodiment is shown in Figures 11A-11H. The supply flow surface is defined by a plurality of non-driven rollers sized and configured to supply inventory items in a unidirectional manner by gravity as they are received from an automated guided vehicle in one of the rows ascending therethrough. Additionally or alternatively, the supply flow surface is defined by a plurality of driven rollers configured to move items in a first direction, away from an automated guided vehicle in one of the ascending rows therethrough, for example, for retrieval by one or more fulfillment station operators, and to move items in a second direction opposite the first direction, for transfer of items to an automated guided vehicle in an ascending row therethrough, for example, during a replenishment operation. In one alternative example, the supply flow surface may be defined by a plurality of horizontally oriented belts driven in first and second directions to perform the same collection and replenishment functions as the drive rollers described above. The columns ascending therethrough in the cases of Figures 11A-11H are shown as being vertically and horizontally movable by the automated guided vehicle in the second mode of operation, but are fixed.

[0168] FIG. 15 is a flow diagram illustrating a process 1500 by which inventory control tasks can be assigned to one or more automated guided vehicles and functional attachment modules. The process 1500 begins at 1502 and continues to 1504 where an inventory control task request is received. The process 1500 continues at 1506 where the process identifies a sequence of subtasks applicable to the task requested at 1504 . From 1506 , the process proceeds to 1508 where the process determines which automated guided vehicle and functional attachment module resources are required to complete one or more of the subtasks identified in 1506 . From 1508, the process proceeds to 1510 where the process determines the time and power requirements for completing the subtask or subtasks identified at 1508. The process 1500 proceeds to decision block 1512 .

[0169] At decision block 1512 , the process determines whether there is a currently pending task with a higher priority than the task request received at 1504 . If no, the process proceeds to decision block 1514 where the process determines whether the required automated guided vehicle and functional attachment module resources are available to allocate to the task request identified in 1504 . If NO, the process returns to decision block 1512; if YES, the process proceeds to 1516 where the process establishes a new task association between the automated guided vehicle and one or more functional attachment modules. From 1516, the process proceeds to 1518, where the process transmits instructions to the one or more automated guided vehicles identified in 1514. The process continues to decision block 1520 . At decision block 1520, the process determines whether all assigned subtasks are complete. If no, the process returns to 1508 to allocate more resources. If yes, the process proceeds to 1522 to determine if the inventory cycle is still active and outstanding, and if yes, the process returns to 1504 . If NO, the process proceeds to 1524 and ends.

[0170] If the process 1500 determines at 1512 that a higher priority task is pending, the process proceeds to 1526, where it assigns a priority to the task request received at 1504, and the process proceeds to 1528. At 1528, the process assigns the current task sequence to a task queue. Note that in this case there may be many such task queues. Of the tasks remaining in the assigned task queue, the process determines which currently has the highest priority and the process returns to decision block 1512 .

[0171] FIG. 16 is a flow diagram illustrating a process 1600 for dynamically allocating inventory items among various storage areas over a series of consecutive inventory intervals. The process 1600 begins at 1602 and proceeds to 1604 where a dynamic slot interval counter is initialized. The facility may be operated over two eight-hour shifts or 16-hour periods. A slot interval of one hour is used and the process proceeds to 1606 and increments by one to represent each slot interval. At 1606, received inventory control tasks scheduled for completion during the current or upcoming slot interval are analyzed and a determination is made as to which inventory items should be placed in a first storage area reserved for high-movement items and which inventory items can be moved to a second storage area appropriate for low-movement items. The process allocates a first subset of inventory items to a first storage area and a second subset of inventory items to a second storage area. The process continues at 1608.

[0172] At 1608, process 1600 initiates operation of a first group of automated guided vehicles to begin moving a first subset of inventory control items from the second storage area to the first storage area, and at 1610 initiates operation of a second group of automated guided vehicles to begin moving a second subset of inventory control items from the first storage area to the second storage area. The process proceeds from 1610 to 1612. At 1612, the process operates a plurality of automated guided vehicles to transport the inventory item to the destination area, the first of the moved first subset of inventory items. From 1612, the process proceeds to 1614, where the process operates a plurality of automated guided vehicles and functional attachment modules to transport inventory items, at least a first of the moved subset of inventory items, to a destination area. The process proceeds to 1616.

[0173] At 1616, the process increments the dynamic slot interval counter by one and proceeds to 1618 to determine whether there are any remaining increment cycles remaining in the current inventory cycle. If yes, the process returns to 1606 to perform the analysis for the next slot window. If no, the process proceeds from decision block 1618 to end block 1620 and ends.

[0174] FIG. 17 is a flow diagram illustrating a process 1700. The automated guided vehicle controller executing process 1700 operates the automated guided vehicle to perform inventory management tasks in a first operating mode using only onboard resources and capabilities of the automated guided vehicle, and in a second operating mode using additional resources and capabilities of one or more functional accessory modules. The process 1700 begins at 1702 and proceeds to 1704 where the method 1700 determines the operational mode required to perform the inventory control task. The process 1700 proceeds to 1708 where the process identifies whether the first operating mode applies, and if yes, the process 1700 proceeds to 1710 .

[0175] At 1710, in a first vehicle operating mode, method 1700 controls rotation of a first drive member of a second drive system of the automated guided vehicle, and proceeds to 1712, where method 1700 aligns the first drive member of the first drive system with a guide system positioned along the array of storage locations of the rack structure. From 1712, the method 1700 proceeds to 1714, where the method 1700 controls the rotation of a second plurality of drive members of the first drive system to move the automated guided vehicle vertically to or from one of the storage locations. Regardless of whether method 1700 performs a task in which an item is retrieved from a storage location of a rack structure rather than placed in the storage location, method 1700 performs steps 1710 through 1712 twice: once to enter the rack structure, reach the target storage location, and operate the vehicle's loading mechanism to retrieve or place the item, and a second time to reverse the order, move away from the target storage location, and exit the rack structure.

[0176] Method 1700 may be performed using an automated guided vehicle in which the first drive members of the first drive system are maintained at a fixed spacing that matches the spacing between the parallel tracks of the guidance system, although such a configuration is not required to perform method 1700. For example, alignment of 1712 may be achieved by performing the further step of using a further drive mechanism to move the first drive members of the first drive system closer together before entering openings defined in the rack structure aligned with the parallel tracks, and then moving the first drive members of the first drive system away from each other to move their respective engagement surfaces to a position where rotation of the first drive members will initiate vertical movement of 1714.

[0177] Referring to FIG. 17, the process 1700 proceeds from 1714 to decision block 1716 where the process 1700 determines if more tasks remain, and if yes, the process returns to 1704 . Method 1700 is configured to proceed from 1708 to 1720, and in a second mode of operation, method 1700 controls rotation of a first drive member of a second drive system to move an automated guided vehicle into or out of an opening defined by a functional attachment module. The method 1700 proceeds from 1720 to 1722, where the method controls rotation of the first drive member of the second drive system to move the automated guided vehicle and functional attachment module horizontally. The method 1700 proceeds from 1722 to 1724, where the method controls rotation of a first drive member of a first drive system to move a function attachment module vertically.

[0178] Note that the order in which 1720 through 1722 are executed depends on the particular task to which they are assigned. For example, the transfer of a functional attachment module from one location to another in an inventory control facility is accommodated by performing 1724 a first time after the automated guided vehicle enters the functional attachment module at the first location and before step 1722 is performed. Once the method 1700 performs 1724 to lift the automated guided vehicle at the first location, step 1722 is performed to move the lifted accessory module. Step 1724 is again executed to lower the functional attachment module onto the lower support surface at the second or target location, and step 1720 is again executed to withdraw the automated guided vehicle from the attachment module.

[0179] For example, if the first accessory module serves as an adapter for lifting the second functional accessory module, steps 1720 to 1724 are performed by method 1700 to retrieve the first functional accessory module and move it to the position of the second functional accessory module, and then steps 1720 and 1724 are performed again so that the automated guided vehicle and first accessory module pair enters the second functional accessory module, lifts it, and moves it horizontally.

[0180] Although the present invention is largely described and illustrated in the context of inventory movements in a warehouse, fulfillment center, or inventory-based distribution center, the present invention applies to the transportation of other types of items, including collections of parts in a manufacturing operation, and the like. Also, the illustrative description refers to specific embodiments. However, it is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teachings. The embodiments may be modified in various ways to suit a particular use.

[0181] The order of the method may be changed, and various elements may be added, rearranged, combined, omitted, modified, etc. All of the examples described in this disclosure are provided as non-limiting. Various modifications and variations may be made as will be apparent to those skilled in the art having the benefit of this disclosure. The embodiments are described in a particular context. These embodiments are illustrative and non-limiting. Many variations, modifications, additions and improvements are possible. Thus, for elements described as singular instances, plural instances may be used. Boundaries between various components, operations and data stores are arbitrary, and specific operations are illustrated in the context of specific configurations. Other allocations of functionality are contemplated and are within the scope of the claims. Finally, structures and functionality shown as separate components may be implemented as a combination of structures or components. These variations, modifications, additions and improvements are intended to fall within the scope defined by the claims.

[0182] Therefore, while the above description is directed to embodiments of the present invention, other embodiments are defined by the claims.

Claims

1. providing a vehicle having a second drive system for driving the vehicle horizontally and a first drive system cooperative with a guide member for driving the vehicle vertically above the guide member; providing a functional attachment module having an opening configured to receive a portion of the vehicle; operating the second drive system to drive the vehicle along a horizontal plane to a position adjacent to the function attachment module; aligning the vehicle with the opening in the functional attachment module; driving at least a portion of the vehicle into the opening; activating the first drive system to vertically lift the function-attached module such that the function-attached module is raised away from the horizontal surface; operating the second drive system to drive the vehicle together with the functional attachment module along the horizontal plane; and placing an item on or retrieving an item from the functional accessory module after the step of operating the second drive system to drive the vehicle together with the functional accessory module. How to handle materials.

2. 2. The method of handling materials of claim 1, wherein driving at least a portion of the vehicle into the opening comprises driving the first drive system into operative engagement with a drive surface of the functional attachment module.

3. the drive surface includes a plurality of teeth cooperable with the first drive system; 3. The method of claim 2, wherein the step of driving the first drive system into operative engagement with the drive surface comprises meshing the first drive system with the plurality of teeth.

4. 10. The method of claim 1, wherein the step of placing an item on the function attachment module comprises moving the function attachment module into engagement with a rack or shelf.

5. 5. A method of handling materials as claimed in any one of claims 1 to 4, comprising the step of operating the second drive system to drive the vehicle horizontally while the vehicle is within the functional attachment module and the item is placed on the functional attachment module.

6. the function attachment module comprises a support surface; 6. The method of claim 5, wherein the step of placing an item on the functional attachment module comprises placing the item on the support surface.

7. Material handling systems that store or retrieve multiple items are a horizontal drive means for driving the vehicle in a horizontal direction; vertical drive means cooperative with a vertical guide member for driving said vehicle vertically up said vertical guide member; a power supply that supplies power to the horizontal drive means and the vertical drive means, a vehicle delivering or collecting the item; a functional attachment module having an opening configured to receive a portion of the vehicle, the functional attachment module having a drive surface cooperable with the vertical drive means; A material handling system, wherein the vehicle is configured to extend into the function-attached module such that the vertical drive means engages the drive surface of the function-attached module, and (a) the vertical drive means is capable of driving the function-attached module in a first direction to lift the function-attached module away from a horizontal surface, and (b) the horizontal drive means is operable to drive the vehicle along the horizontal surface while the function-attached module is lifted away from the horizontal surface.

8. 8. The material handling system of claim 7, wherein the drive surface of the function attachment module comprises a plurality of drive members configured to mate with the vertical drive means.

9. 8. The material handling system of claim 7, wherein the functional attachment module comprises a storage bin, shelf or surface for containing one or more items to be stored or retrieved.

10. 8. The material handling system of claim 7, wherein the function attachment module is operable with the shelf rack to elevate the shelf rack.

11. the vertical drive means projects outwardly from the vehicle; 11. A material handling system as claimed in any one of claims 7 to 10, wherein the drive surface of the functional attachment module comprises a gap configured to align with the vertical drive means to facilitate driving of the vehicle into the functional attachment module.

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