WO2016151505A1

WO2016151505A1 - Robotic drive unit with robotic inventory elevator

Info

Publication number: WO2016151505A1
Application number: PCT/IB2016/051641
Authority: WO
Inventors: Rajesh MANPAT
Original assignee: Manpat Rajesh
Priority date: 2015-03-23
Filing date: 2016-03-23
Publication date: 2016-09-29

Abstract

Described herein is a robotic drive unit (102) with robotic inventory elevator used in warehouse automation system. The robotic drive unit (102) comprises an arm unit (306), a robotic inventory elevator and a driving unit (304). The arm unit (306) comprises one or more extendable arms (406) that extend forward and retrieve products by clamping, and retract backwards. The arm unit (306) is vertically slide-able along an arm supporting structure and places the retrieved products in one of a plurality of compartments (502). The robotic inventory elevator comprises a inventory elevator frame coupled to a supporting member (608) with an elevation mechanism that elevates the inventory elevator frame (504) and the plurality of compartments to provide a passage beneath the inventory elevator frame (504). The passage enables a smaller robotic unit to pass through below the elevator frame (504).

Description

ROBOTIC DRIVE UNIT WITH ROBOTIC INVENTORY ELEVATOR

TECHNICAL FIELD

[0001] The present invention relates to a system and method for automatically storing and retrieving products in a warehouse and, in particular, relates to warehouse automation using Robotic Drive Units (RDU) with Robotic Inventory Elevator (RIE).

BACKGROUND

[0002] A warehouse is a building used for storage of goods or products that are grouped together and stored in multiple storage units like racks, shelves, or compartments. The products may include raw materials, packing materials, spare parts, components, or finished goods associated with agriculture, manufacturing, and production. Warehouses are important for running businesses of manufacturers, wholesalers, customs, etc., as they serve as a single location to store, protect, handle, and redistribute the products to other locations.

[0003] Various operations like storing, retrieving, arranging, supervising, etc., in the warehouses are performed by a personnel department. Over the recent years, fulfilment of such operations and the intent to improve storage efficiencyhas been simplified by using automation systems in the warehouses. For example, conveyors, cranes, robotic drive units and variety of computer-controlled systems are used for automatically placing, transferring, and retrieving goods within the warehouses.

BRIEF DESCRIPTION OF DRAWINGS

[0004] A detailed description is provided with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.

[0005] Fig. 1 illustrates a top view of a warehouse and automation systems, in accordance with an implementation of the present subject matter.

[0006] Fig. 2(a) illustrates a method for storage and retrieval of products by robotic drive units, in accordance with an implementation of the present subject matter.

[0007] Fig. 2(b) illustrates a method for elevating the inventory elevator frame and the arm supporting structure, in accordance with an implementation of the present subject matter. [0008] Fig. 3 illustrates the components of a robotic drive unit, in accordance with an implementation of the present subject matter.

[0009] Fig. 4 illustrates a top view of the arm unit, in accordance with an implementation of the present subject matter.

[0010] Fig. 5 illustrates a side view of a driving unit and robotic inventory elevator, in accordance with an implementation of the present subject matter.

[0011] Fig. 6 illustrates a perspective view of a driving unit and robotic inventory elevator from bottom, in accordance with an implementation of the present subject matter.

[0012] Fig. 7(a) illustrates side view of a robotic drive unit, in accordance with an implementation of the present subject matter.

[0013] Fig. 7(b) illustrates front view of a robotic drive unit, in accordance with an implementation of the present subject matter.

DETAILED DESCRIPTION [0014] The present subject matter relates to a method and system for automatically storing and retrieving products using Robotic Drive Units (RDU) with a Robotic Inventory Elevator (RIE). While the following description uses RDUs as an example, it will be understood that other automated storage and retrieval systems may also be used, as would be evident to a person skilled in the art.

[0015] Generally, a warehouse stores products or goods of various types and serves as a hub in logistics network where goods are temporarily stored and redistributed to different locations. The functioning of warehouse requires procedures and operations, such as storing, handling, retrieving, and supervising. Such operations may be executed in the warehouse by a personnel department. The manual execution of the operations by the personnel or workforce may be time consuming, error prone, or requires more manpower, etc. To meet the demands of a time sensitive market, it has become imperative to automate the functioning of warehouses efficiently, while also ensuring error-free product retrieval and storage.

[0016] Typically, automation systems in warehouses simplify operations like storing, transferring, or retrieving products or goods using manually driven fork trucks, semi- automated robotics, conveyors, etc. For example, robotic drive units of the type having mobility, arms and positioners, pick up products by moving in a workspace are generally used in warehouse automation. In performing tasks such as to pick up or store multiple products or its containers from multi-level inventory racks, each robotic drive unit uses arms and its positioner to access these locations and perform the necessary task action.

[0017] In case of storage, it transfers the product or its containers from onto itself to the storage space or inventory rack and in a retrieving operation, it picks up the product or container from the inventory rack and stores them onto itself or attached peripherals. The robotic drive units may comprise wheels and are driven by motors equipped with guidance sensors and communication capabilities for navigation and executing the operations.

[0018] Automation systems have, therefore, minimized the limitations of the conventional warehouse management methods that involve manual execution by personnel, however, higher efficiency of such systems is required to meet the demands of large businesses. Further, automation systems may not be feasible in all warehouses due to the space required for an installation or high cost of the machines and robots.

[0019] For example, the robotic drive units are efficient up to the extent of bringing the inventory storage rack or inventory pods to the user and not the specific product itself. The inventory pod containing multiple products when lifted and brought to the worker may include many unwanted variants of different products that may not be meant for the current pick and hence contributing to lower efficiency of drive units and the overall system. Further, the unwanted or irrelevant products carried and transported to the worker also means that a second drive unit which might need those products will have to wait for the inventory pod to be placed back to its inventory location to be picked up again by the second robot.

[0020] Further, in conventional warehouse management systems, a robotic drive unit is usually assigned to bring a particular product or inventory pod to the worker location. So, if five products at five different locations are to be retrieved, the conventional system needs five robotic drive units to accomplish the task. Hence more robotic drive units would be required to be employed for order fulfillment in the area of warehouse workspace.

[0021] Some robotic drive units are equipped with arm positioners having limited size and their access to certain locations within a warehouse especially the higher locations on the racks become difficult. Such robotic drive units cannot have larger or taller arms as they would need larger base to support the tall vertical structure which leads to increased size of the pathways. This leads to inefficient usage of warehouse space or leads to the expansion of warehouse space horizontally.

[0022] Some robotic drive units having bi-directional arms are designed to fork operate the products and bring the same from one location to another. However, such robotic drive units may not able to retrieve and move multiple products as a single task from one location to other. Hence robotic drive units with bi-directional arms are confined to only changing one product's location at a time as such robotic drive units would not be able to carry or store multiple products on themselves.

[0023] As mentioned above, the storage capacity of warehouses is not exhaustively utilized, especially the vertical storage space being under-utilized rendering the automation of warehouses inefficient, time-consuming, and requiring more robotic drive units. Therefore, this increases the obstruction between the robotic drive units in the pathways and also increases the cost incurred in management of warehouses. Further, the robotic drive units are not designed to access locations that are higher than the reach of human workers and cannot carry multiple products that are required to be transferred down to the reachable height of human workers.

[0024] In accordance with the present subject matter, a system and method for automatically storing and retrieving products in a warehouse is described. The present subject matter provides a robotic drive unit that can access higher locations and navigates through the warehouse while constantly interacting with a server.

[0025] The robotic drive unit system described herein according to the present subject matter comprises an arm unit, a robotic inventory elevator, a plurality of multi-level compartments, and a driving unit. The arm unit comprises a one or more extendable arms, one or more base arms. Each of the extendable arms is housed inside one of the base arms with a slider coupling. The slider coupling enables the extendable arms to extend forward or backward and can clamp and lift or release a product by means of a gripper. The base arms are connected to vertical arm positioners, which are positioned on an arm supporting structure. The vertical arm positioners are coupled to the arm supporting structure and facilitate vertical movement of the arms with respect to the system.

[0026] The arm supporting structure is mounted vertically on chassis of the robotic drive unit. In one embodiment, the arm supporting structure may be a pair of arm supporting structures to couple with the vertical arm supporters. In another embodiment, the arm supporting structure may be a single supporting axis that couples with an arm holder. The arm holder is slidably coupled to the vertical arm positioners, and holds the vertical arm positioners and the base arm. In an embodiment, the arm supporting structure may be 360° rotatable to store or retrieve the products and to relocate the products in one of a plurality of compartments of the robotic drive unit without rotating the entire robotic drive unit.

[0027] In yet another embodiment, the one or more extendable arms is horizontally movable using horizontal arm positioners. The one or more extendable arms is capable of extending horizontally beyond the chassis of the robotic drive unit, clamp and lift the products of different sizes and shapes, retrieve the products, and store it onto the robotic drive unit by arm retracting operation.

[0028] The robotic inventory elevator is coupled to a processor and comprises an inventory elevator frame and an inventory elevator motor, in one embodiment, the inventory elevator frame is designed to hold the plurality of multi-level compartments. Further, the inventory elevator frame is coupled to supporting members of the robotic drive unit by means of an elevation mechanism. The elevation mechanism may include one or more of a pinion and rack mechanism, a pulley and cable mechanism, and a sliding mechanism.

[0029] The pinion and rack mechanism is achieved by rotational motion of a motor shaft to provide a linear vertical motion of the robotic inventory elevator. The elevation mechanism between the inventory elevator frame and the supporting member elevates the inventory elevator frame and the arm supporting structure along with the plurality of multi-level compartments. The elevation creates a space below the chassis and inventory elevator frame that enables smaller robotic drive units or other man and material to pass below it. This enables parallel operations to be performed at lower inventory levels while the Robotic drive units in an elevated arm and inventory position can operate at higher level of inventory.

[0030] In one embodiment, the robotic drive unit comprises an obstacle detection unit that can detect if an object is obstructing the path of the robotic drive unit. The obstacle detection unit sends a signal to the processor, which enables the processor to initiate the elevation of the inventory elevator frame and the plurality of multi-level compartments. The plurality of multi-level compartments is provided to place the products retrieved by the Robotic Drive Unit. The plurality of multi-level compartments may be a frame or platform that is slide able along the supporting member and fixedly connected to the arm supporting structure. Each compartment may store one or more products clamped and lifted by one or more extendable arms depending on the size of the products.

[0031] The driving unit comprises wheels to enable mobility of the Robotic Drive Unit across the area. It also includes, but is not limited to, a motor for mobility, at least one drive wheel and one or more set of caster wheels for supporting the Robotic Drive Unit. The Robotic Drive Units traverse along the warehouse using the driving unit, which in turn is controlled by the onboard processor.

[0032] The elevation of the robotic inventory elevator enables secondary robotic drive units to pass below robotic drive unit which is enabled by the elevation mechanism of the larger or taller robotic drive unit. The secondary robotic drive units are smaller in size and are used for retrieving products from the larger robotic drive units that are capable of accessing high storage locations. The secondary robotic drive units may hereinafter be referred to as smaller robotic units.

[0033] In view of the above-mentioned, a Robotic Drive Unit (RDU) is provided that can access high locations for storage and carry multiple products that are required to be transferred. Further, the robotic inventory elevator of the robotic drive unit system allows other robots to pass below them and enables them to work without obstruction from other robots, material handling units, or any object and pass below its inventory elevator. Therefore, the present invention increases the storage capacity of a warehouse significantly by utilizing warehouse space exhaustively, coordinating an effort for storing and retrieval of products between robotic drive units of different sizes, and increase the quantity of tasks processed with lesser number of Robotic Drive Units.

[0034] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the scope thereof, and the embodiments herein include all such modifications.

[0035] Figure 1 illustrates a top view of a warehouse 100 in which the present invention is implemented. The warehouse 100 comprises a plurality of inventory racks (Al, A2, B l, B2, CI, C2, Dl, and D2), one or more robotic drive units 102, a server 104, and at least one checkpoint 106.

[0036] In one embodiment of the present invention, the fixed inventory racks (Al, A2, B l, B2, CI, C2, Dl, and D2) comprises multiple storage levels or shelves (not shown in figure) that forms a three dimensional storage to optimize use of floor space. The inventory racks are further divided into storage unit (1-10) to identify the product location. In another embodiment, the checkpoint 104, also known as destination point is a place inside or near the warehouse 100 where personnel receive one or more products from one or more robotic drive units 102.

[0037] The server 104 receives inputs from a user and performs one or more tasks accordingly. In one embodiment, the server 104 stores the warehouse inventory location data that may include product details, such as product identification number, product name, brand, quantity, etc., and storage information of a product, such as product container ID, storage unit number, storage level or shelf ID, inventory rack ID, etc. The server 104 communicates with one or more robotic drive units 102 using any known wireless communication technology to assign tasks. The tasks may be further divided into warehouse operations and the operations can be broadly classified as storing and retrieving. In particular, the task may be communicated by the server 104, which comprises retrieving one or more products from a first inventory rack, transporting the one or more products, and storing the one or more products in a second inventory rack. The RDU may retrieve or store a product from higher location placed on the inventory rack by using the elevation mechanism as communicated by the server. The server carefully monitors the operations performed by the robotic drive units 102 and may also indicate the status of each task to the user. In one embodiment, the server may communicate with the robotic drive unit to elevate the robotic inventory elevator to allow objects to pass beneath it or to access a product stored at higher locations by allocating a task.

[0038] As described above, the warehouse 100 may store many different products at inventory racks present at different locations throughout the warehouse. When an order for one or more products is received by the server 104, the ordered products or the product carrying containers are picked from various locations in the warehouse 100 for further processing, such as billing, packing, shipping, etc. In one embodiment, an order is assigned as task to one robotic drive unit 102 and the robotic drive unit 102 executes the assigned task and performs the second task if available in task queue. Further, the task assigned to a robotic drive unit 102 comprises multiple operations that may include retrieving or storing a product from or to the inventory rack.

[0039] For example, picking five products from the warehouse is assigned as a single "task" to a robotic drive unit which includes five sets of operations for picking products from various locations of the warehouse storage area. In another embodiment, tasks may be assigned to a single robotic drive unit if the product quantity is less than the maximum capacity of the robotic drive unit or if the robotic drive unit is not occupied to its full capacity.

[0040] Fig. 2A illustrates a block diagram 200A for order processing operation in the warehouse, in accordance with an embodiment of the present subject matter. The server 130 receives input from the user that includes details of the product and its location. The details may include one or more of product details, such as product identification number, product name, brand, quantity, etc., and one or more of storage information of a product, such as product container ID, storage unit number, storage level or shelf ID, inventory rack ID, etc. Based on this information, the server selects an unoccupied robotic drive unit.

[0041] In block 202A, the server 104 selects available robotic drive unit 102 and assigns the task to that robotic drive unit 102. An available robotic drive unit refers to a robotic drive unit, which is not fully occupied, and is nearest to the location of the required product. When an order for one or more products is received by the server 104, the server 104 selects one robotic drive unit 102 among the available robotic drive units in the warehouse and assigns the task wherein the task includes picking one or more products from various locations of the warehouse. In one embodiment, the server 104 assigns the task to a robotic drive unit 102 which is nearest to the task location.

[0042] In block 204A, the robotic drive unit 102 accepts the assigned task. In one embodiment, the task is accepted by the robotic drive unit 102 in the form of route map to pick one or more products from various locations of the warehouse. In another embodiment, the route map comprises product and product location information, such as product name or product ID, product carrying container ID, storage unit number, storage level number, inventory rack ID, etc. The route map may include waypoints, sequence of operations to be performed, etc.

[0043] For example, a task may comprise multiple actions Action 1: picking a product "X" from the storage unit "5" of inventory rack "Al"; Action 2: picking a product "Y" from the storage unit "8" of inventory rack "B2"; and Action 3 : picking a product "Z" from the storage unit "4" of inventory rack "Dl". In this example "single storage level or shelf is considered for convenience and understanding. However, the inventory rack may include multiple storage levels and such storage level is indicated in each action. Such task is assigned to the robotic drive unit 102 which is nearer to the task location.

[0044] In block 206 A, the robotic drive unit 102 reaches the first task location and executes the operations associated with the first task. On receiving the route map, the robotic drive unit 102 navigates to the first task location, i.e., to perform "Action 1". The robotic drive unit on reaching the location executes the "Action 1", i.e., picks the product "X" from the inventory rack and stores it on the place provided on the robotic drive unit 102. After executing the first Action, the robotic drive unit 102 navigates to the second and third locations to execute Action 2 and 3, respectively. In one embodiment, the action may be placing a product on the inventory rack. For example, if the task is to place products in various locations of the warehouse, then the robotic drive unit 102 navigates to the respective locations to place the products. [0045] In block 208 A, the robotic drive unit 102 updates the server 104 on task completion. In one embodiment, when the robotic drive unit 102 completes the assigned task, i.e., when the robotic drive unit 102 picks up all the products, the robotic drive unit 102 updates the server 104 that the assigned task has been completed and waits for the next instructions from the server 104. However, if the robotic drive unit 102 reaches the full capacity, the robotic drive unit 102 updates the same to the server 104.

[0046] In block 21 OA, the robotic drive unit 102 receives the destination information to place the products. On receiving the updates from the robotic drive unit 102, the server 104 sends the destination or checkpoint information to the robotic drive unit 102. In one embodiment, the server 104 may assign a second task to the robotic drive unit 102 if the robotic drive unit 102 is not reached its full capacity. For example, the server 104 may instruct the robotic drive unit 102 to pick and bring one or more products which are located on the path of the robotic drive unit 102.

[0047] In block 212A, the robotic drive unit 102 executes the task, i.e., executes one or more actions associated with the task and updates the server. On receiving the instructions from the server 104, the robotic drive unit 102 traverses to the checkpoint 106 where the user may collect the products for further processing. Once the robotic drive unit 102 completes the task, it updates the server 104 as free and ready for the new tasks. In one embodiment, the robotic drive unit 102 may be used to place one or more products from one location to multiple locations in the warehouse.

[0048] Fig. 2B illustrates the steps involved in elevation of the inventory elevator frame and the arm supporting structure to reduce obstruction in pathways in accordance with an implementation of the present subject matter.

[0049] In block 202B, an obstacle detection unit is used to detect the presence of an object in the pathway of the robotic drive unit (102). The obstacle detection unit may comprise sensors, such as ultrasonic sensor, motion sensor, etc., which detect the objects in pathway. The obstacle detection unit sends a signal to the processor indicating the presence of objects in the pathway.

[0050] In block 204B, the processor receives the signal sent by the obstacle detection unit and responds accordingly. In an implementation, the processor may provide signals to an inventory elevator motor that enables the rotational motion of the motor shaft. The motor shaft may comprise a pinion that engages with a rack connected to the supporting member of the robotic drive unit (102). [0051] In block 206B, the motion between the pinion and the rack is initiated which results in the upward vertical motion of the inventory elevator frame with respect to the supporting member. In one implementation, the pinion and rack mechanism may be replaced with other elevation mechanisms.

[0052] In block 208B, the inventory elevator frame, the arm supporting structure along with the plurality of multi-level compartments are elevated and the elevation creates a passage for smaller robotic drive units, man or other material handling units may pass through.

[0053] Fig. 3 illustrates a schematic diagram depicting the components of the robotic drive unit 102, in accordance with an implementation of the present subject matter. The robotic drive unit 102 comprises a processor 302, a drive unit 304, arm and arm positioners 306, product sensors 308, obstacle detection unit 310, vision guidance and navigation unit 312, communication device 314, and robotic inventory elevator 316.

[0054] The processor 302 may be any known processor configured to process data or commands received by the server 104. The processor 302 operates the robotic drive unit to perform various actions based on commands or instructions received from the server as a task and other inputs from the product sensors 308, the obstacle detection unit 310, the vision guidance and navigation unit 312.

[0055] The drive unit 304 moves the robotic drive unit to various locations in the warehouse based on the commands received by the processor 302. The drive unit 304 includes, but not limited to, an inventory elevator motor, at least one drive wheel and one or more set of caster wheels for supporting the robotic drive unit 102. Further, the arm unit 306 of the robotic drive unit 102 comprises at least one arm to hold the products and arm positioners to move the arm(s) vertically or horizontally to pick the products from the inventory rack.

[0056] In addition, the arms may comprise one or more product sensors 308 to recognize or detect the products that need to be picked or placed. For example, the product sensors 308 scan the products to confirm and then perform the operation. The product sensors 308 may include, but is not limited, to barcode readers, RFID scanners, cameras, and the like, as would be known to a person skilled in the art.

[0057] In one embodiment, the robotic drive unit 102 comprises an obstacle detection unit 310 which detects the moving or stationary objects along the travel path and stops the robotic drive unit 102 temporarily. On detection of the obstacle, the robotic drive unit may also elevate using an elevation mechanism. The elevation mechanism elevates the robotic inventory elevator, the arm supporting structure, and the plurality of multi-level compartments.

[0058] In another embodiment, the robotic drive unit 100 comprises vision guidance and navigation unit 312 to navigate the robotic drive units 100 along the warehouse workspace and referencing its own position with respect to objects, text, symbols, codes, patterns, or any landmark present in the warehouse. The vision guidance and navigation unit 312 comprises one or more cameras and local and global positioning systems which captures accurate three dimensional locations and provides feedback to the processor 302 for autonomous navigation. The vision guidance and navigation unit 360 determines the location of the robotic drive units 110 based on the surroundings, such as inventory racks, storage units, last storage unit at which an action has been executed.

[0059] The communication device 314 is configured to communicate with the server 130 for receiving and/or sending task and other instructions. The communication device 370 may be a wireless communication device with Wi-Fi or any other suitable wireless communication technology.

[0060] The robotic inventory elevator 316 may include an inventory elevator motor comprising a motor shaft and an inventory elevator frame. The inventory elevator motor may be connected to the base of the inventory elevator frame. The inventory elevator frame is coupled to the supporting member by an elevation mechanism to provide a vertical movement. The elevation mechanism may be one or more of a pinion and rack mechanism, a pulley and cable mechanism, and a sliding mechanism.

[0061] Fig. 4 is a top view of the arm unit 304 and illustrates the arm movement of the robotic drive unit 102 to hold the products in accordance with an embodiment of the present subject matter. The arm unit 304 comprises an arm holder 402, a pair of base arms 404 and, a pair of extendable arms 406 and arm positioners (not shown in figure). In one embodiment, each extendable arm of the pair of extendable arms 406 are housed inside the base arms 404 with slider coupling to enable the pair of extendable arms 406 to extend forward or backward towards the product or container. The slide able movement of the extended arms is represented by arrow 412. The pair of base arms 404 is connected to vertical arm positioners, which are positioned on the supporting unit. The vertical arm positioners are slide able and coupled to the supporting unit and facilitate vertical movement of the arms with respect to the system. The vertical arm positioners facilitate vertical movement of the arms to position the arms to a particular shelf of the inventory rack. [0062] In another embodiment, the horizontal movement of the arm unit 306, particularly the base arms and extendable arms, is controlled by the horizontal arm positioners 410 to hold the product. The arrows 414 represent the horizontal movement of the base arm 404. The horizontal arm positioners 410 may be a sliding mechanism. In yet another embodiment, the extendable arms comprise arm grippers 408, which are mounted on the slider coupling of the extendable arm. The grippers ensure firm clamping or docking and picking of the product from its rest location and transfer the same to one of the plurality of multi-level compartments of the robotic drive unit 102.

[0063] Fig. 5 illustrates a side view of the driving unit and robotic inventory elevator 316 of the robotic drive unit 102, in accordance with an embodiment of the present subject matter. The chassis unit comprises a robotic inventory elevator316, a plurality of multi-level compartments 502, and a driving unit 304. The robotic inventory elevator is connected to a processor 302 and includes an inventory elevator frame504, elevation mechanism and an inventory elevator motor (not shown in figure). The inventory elevator frame504 is coupled to the supporting member by an elevation mechanism to provide a vertical movement..

[0064] In one embodiment, the inventory elevator frame 504 is coupled to the supporting member by means of a pinion and rack 508. The arm supporting structure is a part of a supporting unit of the robotic drive unit 102. The rotational motion of the inventory elevator motor is used by the pinion and rack mechanism to provide a linear vertical motion of the robotic inventory elevator. The inventory elevator frame504 and plurality of multi-level compartments 502 are elevated using the pinion and rack mechanism and provides smaller robotic drive 102a units to pass below it.

[0065] In one embodiment, the robotic drive unit comprises an obstacle detection unit (not shown in figure) that can detect if another robotic drive unit 102 is obstructing the path of the robotic drive unit 102. The obstacle detection unit sends a signal to the processor 302, which enables the processor 302 to initiate the elevation of the inventory elevator frame 504 and the plurality of multi-level compartments 502. The plurality of multi-level compartments 502 is provided to place the products retrieved by the Robotic Drive Unit 102. The compartments may be a frame or platform that is slidable along the arm supporting unit and fixedly connected to the arm supporting structure 506. Each compartment may store one or more products clamped and lifted by the pair of extendable arms depending on the size of the products.

[0066] The driving unit 304 comprises wheels to enable mobility of the Robotic Drive Unit 102 across the area. It also includes, but is not limited, to motor, at least one drive wheel 510 and one or more set of caster wheels 512 for supporting the Robotic Drive Unit 102. The Robotic Drive Units 102 traverse along the warehouse using the driving unit 304, which in turn is controlled by the onboard processor 302.

[0067] Fig. 6 illustrates a perspective view of the driving unit 304 and robotic inventory elevator 316 from bottom when the robotic inventory elevator 316 is elevated according to an implementation of the present subject matter. The inventory elevator frame 504 is coupled to the arm supporting structure 506 by means of a coupling unit 602 like flange. The base of the inventory elevator frame is connected to an inventory elevator motor 604 which includes a motor shaft 606 coupled to pinion. The teeth of the pinion engage with the teeth of the rack which is provided on one of the supporting member 608 of the robotic drive unit. The rotational motion of the shaft causes the pinion to move relative to the rack and vertical motion of the inventory elevator frame504 is achieved.

[0068] The rotational motion of the pinion is supported by an inventory elevator motor coupled to pinion that drives the robotic inventory elevator vertically upwards or downwards. The upward motion of the robotic inventory elevator elevates the plurality of multi-level compartments carrying products. The elevation of the robotic inventory elevator creates enough space between the two supporting members 608 to allow the passage of smaller robotic drive units 102a.

[0069] The smaller robotic drive unit 102a may not comprise a robotic inventory elevator 316 and may be used to refer different automated storage and retrieval systems. For example, these systems may have a similar structure to that of the robotic drive unit 102 with robotic inventory elevator 316, however, as the name suggests the smaller robotic drive units 102 are smaller in size. This enables the smaller robotic drive unit 102 to pass through the space created by a robotic drive unit 102 with robotic drive inventory elevator.

[0070] Fig 7(a) illustrates the side view of the robotic drive unit 102 according to an implementation of the present subject matter. The robotic drive unit comprises the arm unit 306 coupled to the vertical arm positioner 702, which is slidably coupled to the arm supporting structure 506. The vertical arm positioner 702 can position the base arm to the highest location of the inventory rack. The pair of extended arms 406 from the base arm 404 can extend forward and clamp the required product. The clamping is achieved by the grippers or holders (408) and the vertical arm positioners 702 slide down to an empty compartment on the chassis unit.

[0071] On reaching an empty compartment, the pair of extended arm 406 retracts to retrieve the product and places it on the compartment. The products retrieved may also be distributed to other smaller robotic drive units 102a. The smaller robotic drive units 102a comprise a storage retrieval space where they place products received by the robotic drive unit 102 with robotic inventory elevator. Further, the smaller robotic drive units 102a are capable of passing beneath robotic drive units with robotic inventory elevators. The robotic inventory elevators can elevate the inventory elevator frame504 and allow smaller robotic drive units to pass below them.

[0072] Fig. 7(b) illustrates a front view of the robotic drive unit 102 when the robotic inventory elevator 316 is at a rest position, i.e., non-elevated position. The detection of nearby drive units may be done by obstacle detection unit as described earlier or may be monitored manually by the user. The robotic inventory elevator 316 remains at the rest position unless another drive unit is detected in its vicinity or the server requests for an item to be stored or retrieved which is on a higher inventory level than what can be reached when its elevator being in lower position.

[0073] The navigation of the robotic drive unit in a warehouse is assisted by vision guidance and navigation unit 312 and monitored by the server 104. The vision guidance and navigation unit 312 may be fixed in the inventory elevator frame to navigate the robotic drive unit 102 along the warehouse workspace. For example, the guidance and navigation unit 312 may be embedded along with the processor 304. The robotic drive unit 102 navigates and refers its own position with respect to objects, text, symbols, codes, patterns, or any landmark present in the warehouse.

[0074] The vision guidance and navigation unit 312 comprises one or more cameras and local and global positioning systems that capture accurate three dimensional locations and provides feedback to the processor for autonomous navigation. The vision guidance and navigation unit determines the location of the robotic drive unit 102 based on the surroundings such as inventory racks, storage units, or at a last storage unit at which an action has been executed.

[0075] In robotic drive units 102 without a detection mechanism, navigation capabilities assist in elevating and resting of the robotic inventory elevator 102. For example, the cameras may provide vision guidance to the user operating the robotic drive unit 102 via the server 104. The server 104 may then instruct the robotic drive units 102 whether the elevation of the robotic inventory elevator 316 is required or not.

[0076] Although the subject matter has been described in considerable detail with reference to certain examples and implementations thereof, other implementations are possible. As such, the scope of the present subject matter is not limited to the description of the preferred examples and implementations contained therein.

Claims

CLAIMS I claim:

1. A Robotic Drive Unit (102) for storing and retrieving products in a warehouse (100) comprising:

an arm unit (306) comprising one or more extendable arms (406) extending and retracting to engage with the product, wherein each extendable arm is slidably coupled to a base arm (404);

an arm positioner to provide a vertical and horizontal movement of the arm unit (306);

a robotic inventory elevator (316) coupled to a processor (302), wherein the robotic inventory elevator (316) comprises:

an inventory elevator motor (604) comprising a motor shaft (606), and a inventory elevator frame (504) coupled to the supporting member (608) by an elevation mechanism (508) to provide a vertical movement;

a plurality of multi-level compartments fixed on an arm supporting structure

(506) to place one or more products; and

a driving unit (304) comprising at least one drive wheel (510) and one or more set of caster wheels (512).

2. The Robotic Drive Unit(102) as claimed in claim 1, wherein the arm unit (306) comprises an arm holder (402) to connect the base arms (404) to the arm positioner.

3. The Robotic Drive Unit (102) as claimed in claim 1, wherein the arm positioner includes a vertical arm positioner (702) to provide vertical movement of the arm unit (306).

4. The Robotic Drive Unit (102) as claimed in claim 1, wherein the arm positioner includes a horizontal arm positioner (410) to provide horizontal movement of the arm unit (306).

5. The Robotic Drive Unit (102) as claimed in claim 1, wherein the one or more extendable arms (406) comprises of holder (408) to clamp and lift the product.

6. The Robotic Drive Unit (102) as claimed in claim 1, wherein the plurality of compartments (502) are frames fixed on the arm supporting structure (506).

7. The Robotic Drive Unit (102) as claimed in claim 1, wherein the robotic drive unit comprises an obstacle detection unit (310), wherein the obstacle detection unit (310) detects objects in its path.

8. The Robotic Drive Unit (102) as claimed in claim 1, wherein the obstacle detection unit (310) sends signals to the processor (302) when an object is detected and the elevation mechanism elevates the inventory elevator frame (504), the arm supporting structure (506), and the plurality of multi-level compartments (502).

9. The Robotic Drive Unit (102) as claimed in claim 1, wherein the obstacle detection unit (310) comprises one or more of ultrasonic sensor, laser detectors, and motion sensor.

10. The Robotic Drive Unit as claimed in claim 1, wherein the robotic drive unit comprises a vision guidance and navigation unit (312) to identify objects, codes, symbols, texts, and patterns along its path and determine the location of the robotic drive unit (102).

11. The Robotic Drive Unit (102) as claimed in claim 10, wherein the vision guidance and navigation unit (312) comprises a local and global positioning system to transmit the location of the robotic drive unit to the server within the work space.

12. The Robotic Drive Unit (102) as claimed in claim 1, wherein the elevation mechanism includes one or more of pinion and rack mechanism, pulley and cable mechanism, and sliding mechanism.

13. A method for elevating the Robotic Drive Unit (102), the method comprising:

detecting, by an obstacle detection unit (310), an object in pathway of the robotic drive unit (102);

receiving, by a processor (302), a signal indicating presence of object in the pathway from the obstacle detection unit (310);

initiating, by a robotic inventory elevator (316) coupled to the processor (302), an elevation mechanism between a inventory elevator frame (504) and supporting members (608);

elevating the inventory elevator frame (504) and the arm supporting structure (506) to create a passage below the inventory elevator frame (504).

14. The method as claimed in claim 13, wherein detecting the objects in the pathway is performed by a server (104) and the server communicates the robotic drive unit (102) to elevate the inventory elevator frame (504) and arm supporting structure (506).

15. The method as claimed in claim 13, wherein initiating a pinion and rack mechanism is achieved by engaging a motor shaft with pinion and the supporting member (608) with rack.

16. The method as claimed in claim 13, wherein elevating the robotic drive unit (102) is achieved by allocating a task communicated by the server (104) to the robotic drive unit (102).

17. The method as claimed in claim 16, wherein the task communicated by the server

(104) comprises retrieving one or more products, transporting one or more products, and storing the one or more products.