Apparatus and method for handling goods

Described herein are an apparatus and a method of fulfilling an order. The method includes: determining, by circuitry of an information processing apparatus, the order to be processed; selecting an operator station where the order will be fulfilled, a rack that includes an item required to fulfill the order, and a vehicle to transport the rack to the operator station; transmitting at least a portion of a transportation path to the selected vehicle; and monitoring locations of the selected vehicle along the transportation path based on marker information received for each marker of a plurality of markers that is detected by the selected vehicle, wherein the plurality of markers is located at predetermined positions.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Singapore Patent Application No. 10201500882V and Australian Patent Application No. 2015900362, both filed Feb. 5, 2015, and incorporated herein by reference in their entirety.

FIELD

The present disclosure relates generally to a goods handling system, wherein goods are stored in, and retrieved, from a goods storage area.

BACKGROUND

In a partially automated goods handling system, goods are stored in a goods storage area and transported between the goods storage area and operator stations using transportation vehicles, such as transportation robots. In such a system, the transportation vehicles are navigated through the goods storage area using machine detectable tape that is disposed on the floor of a warehouse along predefined movement paths, or by using lasers that interact with reflective material that is disposed, for example, on walls of the warehouse.

However, such existing goods handling systems require relatively complex transportation vehicles and involve computationally intensive tasks to control the positions of the vehicles. Furthermore, such systems do not control the positions of the transportation vehicles with high precision. Accordingly, there is a requirement for a technique that accurately controls (and monitors) the positions of the transportation vehicles in a seamless and computationally efficient manner.

SUMMARY

An aspect of the present disclosure provides for a method of fulfilling an order. The method comprising the steps of: determining, by circuitry of an information processing apparatus, the order to be processed; selecting an operator station where the order will be fulfilled, a rack that includes an item required to fulfill the order, and a vehicle to transport the rack to the operator station; transmitting at least a portion of a transportation path to the selected vehicle; and monitoring locations of the selected vehicle along the transportation path based on marker information received for each marker of a plurality of markers that is detected by the selected vehicle, wherein the plurality of markers is located at predetermined positions.

According to one embodiment, the order to be processed is determined based on an estimate of time required to fulfill the order.

By one embodiment, the order to be processed is determined based on at least one of a priority of the order, and a time the order has been pending.

By one embodiment, an end point of the transportation path is the operator station, the operator station includes a station queue, and the method further comprises the step of: transferring control of movement of the vehicle to the operator station when the vehicle is in the station queue.

According to one embodiment, the station queue includes a queue entry marker, and wherein the control of movement of the vehicle is transferred to the operator station when the vehicle is disposed over the queue entry marker.

According to one embodiment, the station queue includes a queue exit marker, and wherein the operator station transfers the control of movement of the vehicle back to the information processing apparatus when the vehicle is disposed over the queue exit marker.

By one embodiment, the method further comprises the steps of: generating, by the circuitry, at least one order-fulfilling-information (OFI) for the determined order, each OFI including a different combination of a candidate operator station where the order will be completed, at least one rack grouping that includes all items required to complete the order, and at least one vehicle to transport each rack included in the at least one rack grouping to the candidate operator station; and selecting, by the circuitry, an OFI from the generated at least one OFI to complete the order.

By one embodiment, the method further comprises the step of: computing by the circuitry, for each OFI, a cost (H) for the at least one rack grouping that includes all items required to complete the order as: H=Distance/(1+No. of Common Racks), wherein Distance is the combined distance of all racks in the rack grouping from the candidate operator station, and No. of Common Racks is the number of racks included in the rack grouping that include at least two items of the order.

By an embodiment, the vehicle includes a contact member and a lifting device arranged to controllably raise or lower the contact member relative to the ground.

According to an embodiment, the method further comprises the step of calculating by the circuitry, the transportation path based on a lift state of the contact member of the vehicle.

According to one embodiment, the transportation path is computed using an A* algorithm.

By one embodiment, the method further comprises the step of receiving, by the circuitry, rack marker information that is generated based on a rack marker detected by the vehicle, the rack marker being disposed on the rack to be transported by the vehicle.

According to one embodiment, the marker information received for each marker includes a unique identifier that is extracted from the respective marker by the vehicle, wherein each marker is a machine readable pattern, the machine readable pattern being one of a barcode and a quick response (QR) code.

By an embodiment, the method further comprises the steps of computing an offset between one of the monitored locations of the vehicle and an orientation of the marker; and calculating a compensation path for the vehicle based on the computed offset.

By one embodiment, the method further comprises the step of monitoring locations of each a plurality of vehicles based on marker information received for each marker of the plurality of markers that is detected by the respective vehicle.

An aspect of the present disclosure provides for an information processing apparatus, comprising: circuitry configured to determine an order to be processed, select an operator station where the order will be fulfilled, a rack that includes an item required to fulfill the order, and a vehicle to transport the rack to the operator station, transmit at least a portion of a transportation path to the selected vehicle, and monitor locations of the selected vehicle along the transportation path based on marker information received for each marker of a plurality of markers that is detected by the selected vehicle, wherein the plurality of markers is located at predetermined positions.

By one embodiment, the order to be processed is determined based on an estimate of time required to fulfill the order.

According to one embodiment, in the information processing apparatus, the order to be processed is determined based on at least one of a priority of the order, and a time the order has been pending.

By one embodiment, in the information processing apparatus, an end point of the transportation path is the operator station, the operator station includes a station queue, and the circuitry is further configured to: transfer control of movement of the vehicle to the operator station when the vehicle is in the station queue.

By one embodiment, the station queue includes a queue entry marker, and wherein the control of movement of the vehicle is transferred to the operator station when the vehicle is disposed over the queue entry marker.

By one embodiment, the station queue includes a queue exit marker, and wherein the operator station transfers the control of movement of the vehicle back to the information processing apparatus when the vehicle is disposed over the queue exit marker.

According to an embodiment, the circuitry included in the information processing apparatus is further configured to wherein the circuitry is further configured to: generate, at least one order-fulfilling-information (OFI) for the determined order, each OFI including a different combination of a candidate operator station where the order will be completed, at least one rack grouping that includes all items required to complete the order, and at least one vehicle to transport each rack included in the at least one rack grouping to the candidate operator station; and select an OFI from the generated at least one OFI to complete the order.

By an embodiment, the circuitry is further configured to: compute, for each OFI, a cost (H) for the at least one rack grouping that includes all items required to complete the order as: H=Distance/(1+No. of Common Racks), wherein Distance is the combined distance of all racks in the rack grouping from the candidate operator station, and No. of Common Racks is the number of racks included in the rack grouping that include at least two items of the order.

By one embodiment, the vehicle includes a contact member and a lifting device arranged to controllably raise or lower the contact member relative to the ground.

By one embodiment, the circuitry is further configured to calculate the transportation path based on a lift state of the contact member of the vehicle, wherein the transportation path is computed using an A* algorithm.

By an embodiment, the circuitry is further configured to receive rack marker information that is generated based on a rack marker detected by the vehicle, the rack marker being disposed on the rack to be transported by the vehicle.

By an embodiment, the marker information received for each marker includes a unique identifier that is extracted from the respective marker by the vehicle, wherein each marker is a machine readable pattern, the machine readable pattern being one of a barcode and a quick response (QR) code.

According to an embodiment, the circuitry is further configured to: compute an offset between one of the monitored locations of the vehicle and an orientation of the marker; and calculate a compensation path for the vehicle based on the computed offset.

By one embodiment, the circuitry is further configured to monitor locations of each a plurality of vehicles based on marker information received for each marker of the plurality of markers that is detected by the respective vehicle.

An aspect of the present disclosure provides for a non-transitory computer readable medium having stored thereon a program that when executed by a computer, causes the computer to execute a method of fulfilling an order, the method comprising: determining the order to be processed; selecting an operator station where the order will be fulfilled, a rack that includes an item required to fulfill the order, and a vehicle to transport the rack to the operator station; transmitting at least a portion of a transportation path to the selected vehicle; and monitoring locations of the selected vehicle along the transportation path based on marker information received for each marker of a plurality of markers that is detected by the selected vehicle, wherein the plurality of markers is located at predetermined positions.

By one embodiment, in the non-transitory computer readable medium, the order to be processed is determined based on an estimate of time required to fulfill the order.

According to one embodiment, the order to be processed is determined based on at least one of a priority of the order, and a time the order has been pending.

According to one embodiment, in the non-transitory computer readable medium, an end point of the transportation path is the operator station, the operator station includes a station queue, and the method further comprises: transferring control of movement of the vehicle to the operator station when the vehicle is in the station queue.

By one embodiment, the station queue includes a queue entry marker, and wherein the control of movement of the vehicle is transferred to the operator station when the vehicle is disposed over the queue entry marker.

By one embodiment, the station queue includes a queue exit marker, and wherein the operator station transfers the control of movement of the vehicle back to the information processing apparatus when the vehicle is disposed over the queue exit marker.

By one embodiment, in the non-transitory computer readable medium, the method further comprises: generating at least one order-fulfilling-information (OFI) for the determined order, each OFI including a different combination of a candidate operator station where the order will be completed, at least one rack grouping that includes all items required to complete the order, and at least one vehicle to transport each rack included in the at least one rack grouping to the candidate operator station; and selecting an OFI from the generated at least one OFI to complete the order.

According to one embodiment, step of selecting further comprises computing for each OFI, a cost (H) for the at least one rack grouping that includes all items required to complete the order as: H=Distance/(1+No. of Common Racks), wherein Distance is the combined distance of all racks in the rack grouping from the candidate operator station, and No. of Common Racks is the number of racks included in the rack grouping that include at least two items of the order.

By one embodiment, the vehicle includes a contact member and a lifting device arranged to controllably raise or lower the contact member relative to the ground.

According to an embodiment, the non-transitory computer readable medium, further comprises: calculating the transportation path based on a lift state of the contact member of the vehicle, wherein the transportation path is computed using an A* algorithm.

By one embodiment, in the non-transitory computer readable medium, the method further comprises: receiving rack marker information that is generated based on a rack marker detected by the vehicle, the rack marker being disposed on the rack to be transported by the vehicle.

By one embodiment, in the non-transitory computer readable medium, the marker information received for each marker includes a unique identifier that is extracted from the respective marker by the vehicle.

According to one embodiment, in the non-transitory computer readable medium, each marker is a machine readable pattern, the machine readable pattern being one of a barcode and a quick response (QR) code.

By one embodiment, the method further comprises the steps of computing an offset between one of the monitored locations of the vehicle and an orientation of the marker; and calculating a compensation path for the vehicle based on the computed offset.

By one embodiment, the method further comprises the steps of: monitoring locations of each a plurality of vehicles based on marker information received for each marker of the plurality of markers that is detected by the respective vehicle.

DETAILED DESCRIPTION

Exemplary embodiments are illustrated in the referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. No limitation on the scope of the technology and of the claims that follow is to be imputed to the examples shown in the drawings and discussed herein.

The embodiments are mainly described in terms of particular processes and systems provided in particular implementations. However, the processes and systems will operate effectively in other implementations. Phrases such as “an embodiment”, “one embodiment” and “another embodiment” may refer to the same or different embodiments. The embodiments will be described with respect to methods and compositions having certain components. However, the methods and compositions may include more or less components than those shown, and variations in the arrangement and type of the components may be made without departing from the scope of the present disclosure.

The exemplary embodiments are described in the context of methods having certain steps. However, the methods and compositions operate effectively with additional steps and steps in different orders that are not inconsistent with the exemplary embodiments. Thus, the present disclosure is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features described herein and as limited only by the appended claims.

Furthermore, where a range of values is provided, it is to be understood that each intervening value between an upper and lower limit of the range—and any other stated or intervening value in that stated range is encompassed within the disclosure. Where the stated range includes upper and lower limits, ranges excluding either of those limits are also included. Unless expressly stated, the terms used herein are intended to have the plain and ordinary meaning as understood by those of ordinary skill in the art. The following definitions are intended to aid the reader in understanding the present disclosure, but are not intended to vary or otherwise limit the meaning of such terms unless specifically indicated.

Turning now toFIG. 1is illustrated a goods handling system10. The system10includes a plurality of goods racks12, each of which is configured to hold several goods items that may be included in an order, such as a customer order. Goods handling system10also includes one or more operator stations14and a plurality of vehicles16that transport goods racks12between a goods storage area23and one or more operator stations14. In an example, the vehicles can be transportation vehicles or transportation robots.

Movement of the transportation vehicles16is managed by a management system18, in communication with the operator station(s)14and the transportation vehicles16, through a communication network19, such as a wireless communication network and the like. By one embodiment, the management system18comprises an information processing apparatus such as a server (described later with reference toFIG. 8) that includes circuitry configured to control the navigational, monitoring, and other tasks described herein. In operation, items required to fulfil an order are transported between the goods storage area23and the operator station14by at least one transportation vehicle16. Orders are fulfilled in part, by transporting racks12including items of the order. The goods handling system also includes markers20aand20bthat are disposed, for instance, on the floor of a warehouse, and that enable navigating the vehicle16from one point to another. The inbound inventory process and outbound order fulfillment process are managed in this example by the management system18.

FIG. 2illustrates an exemplary warehouse in which the goods handling system10ofFIG. 1can be implemented. The warehouse includes a plurality of markers20a-20ddisposed on a floor21of the warehouse.FIG. 2illustrates multiple markers20a-20d, which are classified by one embodiment, according to the type and/or location of markers within the warehouse. However, only some of the markers (20a-20d) have been labeled so as not to clutter the illustration. Reference to a particular marker20a,20b,20c, or20dcould refer to any of the particular labeled markers.

The racks12are stored in a goods storage area23. In this example, the markers can be categorised as warehouse markers20adisposed generally between the goods storage area23and the operator station(s)14a-14c. Rack markers20bare associated with and disposed under a rack12when the associated rack12is disposed at a defined storage location in the goods storage area23. Queue entry markers20care disposed at entry locations of station queues22, and queue exit markers20dare disposed at exit locations of station queues22. It will be understood, however, that markers may in addition, or alternatively, be disposed elsewhere, such as on the walls.

By one embodiment, the markers20a-20dare in the form of a machine readable barcode. However, any machine readable markers that are capable of being individually identified such as an RFID tag, QR codes and the like may be incorporated by embodiments described herein. Each marker20a-20dhas associated unique identification information that is linked to navigational information. The identification information can be used to control movement of a vehicle between one of a first marker20a-20dand at least one other of markers20a-20d. For each marker20a-20d, the navigational information defines the direction and distance between the first marker20a-20dand every other marker20a-20dthat has been associated with the first marker20a-20d. In some embodiments, other markers20a-20dcorrespond to possible obstacles or areas of interest from the first designated marker20a-20d. The other markers20a-20dcan be adjacent to the first marker20a-20dor within a pre-determined distance.

From the navigational information, navigation paths can be defined between multiple markers20a-20dby identifying each marker20a-20d, as a vehicle16passes over or adjacent to the marker20a-20d. By one embodiment, sensors, such as one or more cameras can be located on a bottom surface of vehicle16. As vehicle16drives across a marker20a-20d, the sensor identifies the particular marker20a-20d, and thereby identifies a location of vehicle16.

According to one embodiment, a server controls the navigation operations of the vehicles16in the warehouse. Specifically, as a vehicle16traverses over a particular marker, the vehicle16captures an image of the marker and transmits the captured image to the server. The server upon receiving the marker image, processes the marker image, to determine the unique information identification associated with the marker. Additionally or alternatively, by one embodiment, the vehicle16upon capturing the image of the marker may process the image to determine the unique identification information and thereafter transmits the identification information to the server.

The server processes the received marker image and/or the unique identification information associated with the marker, to transmit navigational information that is stored in a map database (also referred to herein as a marker map and described later with reference toFIG. 7) to the vehicle16. By one embodiment, the server transmits navigational information to the vehicle16on a hop-by-hop basis. Specifically, in order to navigate a vehicle16between a source marker and a destination marker, a transportation path is computed (by the server) that indicates a sequence of markers between the source marker and the destination marker that are to be traversed by the vehicle16. Further, for the given sequence of markers that are traversed by the vehicle16, each time the vehicle16captures, and thereafter transmits (to the server), the image of, or unique identification associated with, the marker at which it is currently disposed over, the server transmits to the vehicle16, navigational information from the current marker to the next subsequent marker in the sequence of the markers.

By one embodiment, in order to navigate the vehicle16between the source marker and the destination marker, the server computes a transportation path that indicates a sequence of markers between the source marker and the destination marker that are to be traversed by the vehicle16. Thereafter, the server transmits to the vehicle16, navigational information corresponding to the traversal of a plurality of consecutive markers in the sequence of markers. For instance, the server may transmit navigation information corresponding to the traversing of five consecutive markers in the sequence of markers. In doing so, the present disclosure incurs the advantageous ability of utilizing the communication bandwidth of the goods handling system10in an efficient manner.

It will be appreciated that since each marker20a-20dhas navigational information associated with it that is used to instruct a vehicle16to move from one marker20a-20dto an adjacent marker20a-20d, the markers20a-20ddo not need to be disposed on the floor21of the warehouse in any predefined pattern. The markers20may be disposed on the floor21at locations that are appropriate for the configuration of the warehouse. In addition, the markers20a-20dmay be disposed elsewhere, for example on walls or racks.

Navigational information can also be used to prevent collisions and to prevent and resolve deadlock situations with multiple vehicles16. In an embodiment, a vehicle16can reserve a portion of its navigation path before embarking on the navigation path. Portions of a navigation path are reserved since only one vehicle16at a time can occupy the same portion or segment of a navigation path. If the portion of the navigation path is available, the vehicle16makes the reservation and begins to move towards its destination point. As the vehicle16passes through the reserved portion of its path, the reserved portion becomes unreserved, so as not to hinder another vehicle16from travelling through the same reserved portion. By one embodiment, the vehicle16continues to reserve successive portions of its navigation path and un-reserve the traveled portions.

A moving reservation can be made to reserve a pre-determined number of path segments while a vehicle16is travelling on a navigation path. The number of reserved path segments may be dependent upon the particular region of the navigation path, such as turning a corner, traversing a one-way area, moving around an obstacle, or any movement that would likely encumber another nearby vehicle16within a section of the same navigation path.

According to one embodiment, two vehicles16may need to pass through the same region at the same time, such as an intersection. In this situation, a vehicle16can reserve a portion of its navigation path that traverses through the intersection. In addition, the vehicle16can place a safety reservation on the intersecting portion of the intersecting path, so that another vehicle16does not travel through the intersection while the first vehicle16is traveling through the intersection. After the first vehicle16has traveled through the intersection, the first vehicle16can release the safety reservation.

According to one embodiment, a deadlock manager can be notified when a first vehicle16, or an obstacle is blocking a second vehicle16in its navigation path. The deadlock manager can create a dependency graph. When there is a cycle within the graph, i.e. a cyclic dependency, the deadlock manager can take control of the deadlock situation and move one of the vehicles16in the cycle out of the loop so the other vehicle16can proceed on its navigation path. If an obstacle is blocking a vehicle16from proceeding forward, the navigation path can be altered by the deadlock manager to allow passage of the vehicle16back onto its navigation path.

Embodiments described herein can also prevent deadlock situations from occurring. When a navigation path is calculated for a particular vehicle16, the navigation path may be stored in a separate database. When a vehicle16is about to reserve a particular section or segment of a navigation path, a database query is performed to determine whether another vehicle16has a planned navigation path for that particular section or segment under consideration. If so, a safety reservation of each segment of the overlapping paths is made by the vehicle16until a section of the navigation path is reached in which there is no potential deadlock point. No other vehicles16can reserve a segment or section in which a safety reservation is present. In an embodiment, another vehicle16can enter and leave the safety zone, but it cannot stop in the safety zone. Embodiments for preventing deadlock situations consider the actual navigation path, as well as the time of travel upon the navigation path.

FIG. 3depicts an exemplary transportation vehicle16. The vehicle16may be a transportation vehicle or a transportation robot. The vehicle16includes a body30and wheels34, at least some of which are individually controllable so as to control the speed and direction of movement of the vehicle16. Various types and sizes of wheels34are contemplated by embodiments described herein, which may depend upon the type of floor surface. For example, smaller wheels can be used on a smooth hard floor surface, whereas larger rubber wheels may be needed on a rough floor surface. A contact plate36can be controllably raised or lowered relative to the body30in order to raise or lower a goods rack12disposed on the transportation vehicle16, and thereby facilitate transport of the goods rack12between the goods storage area23and an operator station14.

A goods rack12transported by a vehicle16is illustrated inFIG. 4. As illustrated, the contact plate36is disposed in a raised position and consequently raises the goods rack12relative to the floor21. In an example, the goods rack12can be raised by the contact plate36of the vehicle16by about 5-10 cm, for example. However, other raised dimensions are contemplated by embodiments described herein, which may depend upon factors such as the type of floor, the smoothness of the floor, the levelness of the floor, and or a total weight of goods carried by the rack12. For instance, if the weight of the goods on the rack is above a certain predetermined threshold weight, the height of the rack can be set to a predetermined height level (corresponding to the total weight) in order to ensure a low-centre of gravity of the vehicle. In doing so, the present disclosure incurs the advantageous ability of ensuring that the rack is stable and goods on the rack can be transported from one location to another without the fear of goods items toppling over. Additionally, the goods rack12includes one or more shelves40, each of which incorporates several item-receiving locations that are capable of receiving goods items42. The item-receiving locations may further be separated by compartments thereby providing ease of access to an operator who is assigned to a workstation in retrieving the goods.

Turning now toFIG. 5is illustrated an exemplary operator station14. The operator station14can be configured as a pick and/or put station depending on whether the operator station14is used for one or both of adding new goods items to the goods storage area23and retrieving items to fulfil all or a portion of an order from the goods storage area23.

As shown inFIG. 5, the operator station14includes a plurality of order bins46, each order bin46being used to receive items that form part of an order. It will be understood that when retrieval of items to fill an order is automated, and disposal of the items in the order bins46is controlled by the system10, the system10is capable of fulfilling multiple orders at the same time. Multiple orders can also be fulfilled at the same time when the pick and/or put station is able to accommodate more than one person.

The operator station14ofFIG. 5is illustrated during an order-fulfillment process, wherein goods items42that form part of an order are retrieved from the goods storage area23and disposed in an order bin46by an operator. The order bin46is assigned to the order by a server of the system10. The operator station14includes a control unit48configured to control and coordinate operations in the operator station14. The operator station14also includes a pointing device50, such as a laser pointer and a scanner52configured to scan an identifier disposed on a goods item42. The identifier may be any computer-readable identifier, including a line barcode or a matrix code, such as a QR code.

When goods items42are transported to the operator station14by a transportation vehicle16, a goods item42that forms part of an order currently being fulfilled is identified by a pointing device50. In this example, a laser pointer points towards the goods item42. In one embodiment, the laser points to a code that includes, but is not limited to a barcode or a matrix code. In addition, different laser colours can be used to identify goods items42for multiple orders to be placed in associated multiple bins. The use of different laser colours or other distinguishing identification methods is beneficial when the same goods rack12includes the same or different goods items that can fulfil multiple orders.

After removing the identified goods item42from the rack12, the operator at the operator station14may scan the barcode or matrix code on the goods item42using the scanner52. In doing so, the goods item42may be verified by the control unit48, thereby ensuring that the correct goods item42for the current order has been removed from the rack12. The appropriate order bin46for the goods item42is then indicated to the operator, for example by illuminating a light at the order bin46. In the case of different laser colors, the light for the order bin46may be configured to match the laser color used for the corresponding order.

By one embodiment, each marker20a-20dhas associated navigational information that identifies a navigation path from a first marker to one or more other markers, such as markers that are located adjacent to the first marker. In this way, a marker map is defined for all markers20a-20d, with each marker20a-20dhaving associated information that effectively defines the location of the first marker relative to other markers along one or more pre-determined paths.

FIG. 6illustrates a graph theory representation60of a marker map. The graph60includes nodes62(each of which represents one of the markers20a-20d), and edges66. Edges66indicate that a connection exists between two markers20a-20d. Specifically, an edge66connecting two markers indicates that a vehicle16can directly travel from one marker to the other marker, without visiting any other intermediate marker. Thus, all the edges considered as a whole, define the position of the markers20a-20drelative to each other.

According to one embodiment, the server may maintain data corresponding to the connectivity relationship between the different markers in a database (referred to herein as a marker-map). The data can be stored in a key-value type database, with the barcode (or unique identification information) as the key and the properties associated with the barcode as the value. The properties can be defined in such a way that certain requirements can be fulfilled, such as a listing of neighbour markers within the navigation data and the like. Accordingly, rather than storing marker positions as absolute points in space, in the present embodiment, the marker positions are stored relative to each other. In doing so, the present disclosure provides the advantageous ability of identifying, in a time efficient manner, the connectivity relationships between the markers. Accordingly, the server utilizes the marker-map to determine routes between a source marker and a destination marker.

By one embodiment, the marker map is a database system that stores all data related to detectable points on a surface, such as a floor of a warehouse. Each point represents a two-dimensional area in territory. The code from a first marker can be verified as being in the marker map. The code can be a barcode, which is one point in a map structure denoted by a unique string, which is encoded into the marker. Adjacent or nearby neighbour markers20a-20dof the first marker can also be listed by storing the marker information of each marker relative to every other marker. In doing so, a savings in processing power and time consumed in calculating a distance to another marker is provided.

Embodiments described herein for a marker map are capable of determining whether a barcode exists in the marker map, and further listing the barcodes of all neighboring markers of the marker. For a particular barcode, the marker map lists neighbor markers, which will be affected if a rack of a particular size is rotated about a barcode. The marker map can also list the neighboring markers, wherein a particular vehicle16can travel to from its current barcode, depending upon the state of the vehicle16. For each neighbor of a barcode, the marker map stores navigational information as to how to reach each neighbor marker. Navigational information may be in terms of a heading angle measured with respect to a reference point, a distance to travel, and the like. However, it must be appreciated that other navigation identifications can be used with embodiments described herein.

Additionally, the marker map may also store information pertaining to a navigation path between two markers. A navigation path and instructions from the first marker to each neighbouring marker20a-20dmay also be listed. Conditions, such as a raised lift carrying a rack12, or a lowered lift are included in the navigation instructions to each neighbour marker20a-20d. In addition, any neighbouring markers20a-20d, which will be affected by the rotation of a particular sized rack12, can be listed.

In what follows is described by one embodiment, a marker map structure that may be used with a vehicle navigation system of the present disclosure. It must be appreciated that embodiments described herein are not limited to the particular map structure: The particular map structure is represented in two-dimensional space. However, other embodiments can utilize a three-dimensional (or higher) extension of the particular map structure described herein.

Table I depicts an exemplary marker map structure illustrating information stored for markers. For the sake of illustration, only information corresponding to four markers is depicted in Table I. However, it must be appreciated that the marker map may store information corresponding to other barcodes as well. In Table I, BARCODE corresponds to the barcode number of the marker, BOTID corresponds to the identification number of the vehicle currently disposed on the barcode, BLOCKED represents whether or not the barcode is reserved, NEIGHBOURS is a 12-bit binary field storing information pertaining to the neighbours of the marker, ZONE depicts the geographical area in the warehouse where the marker is disposed, the SIZE_INFO numbers are the distance the current barcode is away from its four (north, east, south and west) neighboring barcodes, and STORE_STATUS is binary entity depicting whether a rack can be put at the barcode (1—yes, 0—no).

According to one embodiment, the field NEIGHBOR is a twelve digit binary field wherein, three digits are reserved for each barcode that is an immediate neighbor of the barcode in the North, South, East, and West direction respectively. However, a neighbor in each of those directions is not necessarily present for each barcode. Each of the three digits (corresponding to a direction) represents the following information (expressed with reference to the North direction): (a) whether a barcode exists exist in the north direction? (1—yes, 0—no), (b) can a vehicle travel to the north barcode without a rack? (1—yes, 0—no), and (c) can the vehicle travel to the north barcode with a rack? (1—yes, 0—no).

FIG. 7depicts a table70according to one embodiment, illustrating partial data from another exemplary marker map. The data is indicative of each marker20a-20drelative to other markers20a-20d. The navigational information indicative of the positions of the markers20a-20dand their relative positions to other markers20a-20dis stored in a database.

The table70includes a source field72including unique information identifying a source marker, a destination field74specifying a destination marker, and a method of traversal field76that indicates whether a transportation vehicle is required to travel over relatively flat ground, in an elevator, or on an incline between the source and destination markers. Table70also includes a details field78of the direction, elevation, and distance navigation values that define the navigational information required for a transportation vehicle16to move along a navigation path from the source marker to the destination marker. Additionally, Table70includes a cost field80that indicates the respective ‘cost’ of the transportation vehicle16moving along the navigation path in terms of the amount of time taken.

In the exemplary data illustrated inFIG. 7, the goods storage area23may be disposed over several levels (stories) of a building. Therefore, in order to travel between different levels of the building, the transportation vehicle16may be required to travel in an elevator. For this purpose, a marker may be disposed in the elevator. As illustrated in table70, for a marker disposed in an elevator, the source and destination fields72,74also include information indicative of the current floor, such as floor21at which the elevator is disposed. The details field78also includes information that uniquely identifies the elevator. In another embodiment, each floor level could be assigned one or more vehicles16. As a result, only the rack12may need to travel in the elevator without the vehicle16. The rack12could be loaded and unloaded by different vehicles16, wherein a first vehicle16could load the rack12onto the elevator at the first floor level, and a second vehicle16could unload the rack12from the elevator at the second floor level.

Turning toFIG. 8is depicted an exemplary block diagram81illustrating functional components of a management system of the goods handling system. The functional components81are implemented by circuitry and use any suitable arrangement, for example a suitable computing device with associated processor(s), memory, and data storage (described later with reference toFIG. 16). In an embodiment, the functional components81include one (or more) servers working in conjunction with one or more databases. It must be appreciated that the servers described herein are not limited to any specific combination or hardware circuitry and/or software.

The functional components81include a data storage device82, such as a hard disc drive (HDD) or a solid state device (SSD), represented inFIG. 8as a database, although it will be understood that any suitable data storage arrangement is contemplated by embodiments described herein. The data storage device82is arranged to store marker data83indicative of a marker map of the type represented inFIGS. 6 and 7, and Table I. Marker map83can include the unique identifying information associated with each marker20a-20dand the navigational relationships with other markers20a-20d.

The functional components81also include an inventory manager84that manages the process of adding new goods items42to the warehouse, and records the current inventory of goods items42in an inventory database86. The inventory database86also includes information indicative of the respective storage locations of the racks12in the warehouse and of the locations of the goods items42on the racks12. In this way, the storage locations of all goods items42in the warehouse are known.

An order generator88manages receipt of orders from customers, such as orders received through an on-line checkout system associated with an electronic commerce website. Created orders are managed by an order manager90that stores details of the created orders as order entries in a pending orders database92. The order manager90handles the orders posted by a client, such as posted orders through a network interface112. The network interface112formats the incoming order to process them and posts them to the system10using one or more order application programming interfaces (APIs). The orders are posted to the pending orders list.

By one embodiment, the order manager90forms an order processing loop in which pending orders are to be processed, in order to find the optimum order under present conditions in which to process the pending orders. For a large volume of pending orders, filters can be used to obtain desired results. For instance, a first exemplary filter is an incoming racks filter. If any pending orders can be fulfilled by a rack that is already located at an order-processing station, those orders are placed at a higher position on the pending orders queue to increase the chances of those orders being processed, while at least one of the necessary racks12is still located at the order-processing station. Additionally, a second exemplary filter may be a client priority filter, or an orders priority filter in which specially-designated orders have been flagged for expedited service. A third exemplary filter may be an age filter (i.e., how long has a current order been pending the system) in which older orders are processed before newer orders.

The order manager90also manages the timing fulfillment of the pending orders in the orders database92. In an example, the order manager90is configured to initiate the processing of a pending order when a trigger signal is generated to indicate that an order bin46at an operator station14is available to fulfil an order.

The prioritized pending orders list is forwarded to an order processing loop to get a set of goods inventory that can fulfil the order. All combinations of goods items (along with their associated rack12identification) and the different order-processing stations are generated to form item fulfilling combinations (IFCs), also referred to herein as an order-fulfilling list (OFL). Different rack combinations are generated for each IFC, i.e. the combination of racks containing goods items42for the particular order at a particular order-processing station.

The order manager90manages the sequence of fulfillment of pending orders by calculating a ‘cost’ of each pending order and initiating fulfillment of orders based on a minimum ‘cost’. The order ‘cost’ is related to the time taken to transport all of the required racks for an order to a designated operator station14. However, other cost factors may replace or be considered along with the time taken in other embodiments.

In an embodiment, the ‘cost’ can be subdivided into a distance cost, a racks cost, and a pick and/or place station (PPS) load cost. The distance cost can include the total distance to be covered by the one or more vehicles16between the selected racks12and the PPS for completion of the order. A racks cost includes the total number of racks12used to complete an order. Rack combinations having a fewer number of racks will minimize travel time of the one or more vehicles16in completing an order. A PPS load cost includes finding an optimum balance between the nearest or nearby PPSs and availability or minimal wait time at each PPS. A PPS is one example of an order-processing station. However, any station configured to organize, assemble, and/or prepare items for shipment is contemplated by embodiments described herein. An order-processing station could also be used to organize, assemble, and/or redirect items within a manufacturing environment.

For each order selected for processing, an operator station14is selected, one or more racks12that include the goods items42required for the order are reserved, and an order bin46at the operator station14is reserved. In order to calculate the cost of a pending order, all racks12that could potentially provide a goods item42are first identified and a rack set listing of the identified racks holding the goods item42is defined. A rack set listing is defined for each goods item42. A rack combination comprising a rack12selected from each rack set is then selected from the determined rack sets by calculating the following heuristic for each rack combination:
Heuristic,H=Distance/(1+No. of Common Racks)  (1)
where Distance is the combined distance of all racks12in a rack combination from an available order bin46, and No. of Common Racks is the number of racks12in the rack combination that are common to more than one rack set. The heuristic H is calculated for all available order bins of the operator stations14.

By one embodiment, the rack combination with the smallest or least heuristic H value is selected and the ‘cost’ associated with the selected rack combination is the time required for all racks12in the combination to move to the operator station14with the selected order bin46. Further, the racks12that are included in the selected rack combination are reserved and identified in a reserved database94. In a similar manner, the selected operator station14and the selected order bin46at the operator station14are also reserved by specifying the selected operator station14and order bin46in the reserved database94.

Additionally, the functional components of block diagram81also include a task manager96that selects at least one vehicle16for the fulfillment of an order, when the order is selected for processing. The vehicles16are selected based on availability, task priority, and ‘cost’ of the task. The available vehicles16are identified and within the identified available vehicles16, a set of vehicles are selected based on vehicles16currently free or in a pause state and proximity of the vehicles16to the racks12in the selected rack combination for the order. Each selected vehicle16is assigned a task to retrieve a particular rack12from the goods storage area23. The vehicle(s)16selected for the order are stored in an assigned vehicles database98.

The functional components of the block diagram81also include a planner100that controls and coordinates the planning and reservation of navigation paths for the selected vehicles16within a vehicle map structure. The planner100also plans for implementation of the movements of the vehicles16to and from the selected operator station14, including control over vehicle start/stop actions and vehicle pausing/unpausing actions. The planner100also manages charging of the vehicles16, including checking the charge state of the vehicles16and movement of the vehicles16requiring charging to a vehicle charging station. The planner100plans the execution of an assigned task, which includes but is not limited to, waiting for the vehicle16to achieve a ready state, changing the reservation status and updating the status of the task, checking the charge level of the vehicles16, and assigning tasks to be charged. Managing the flow of vehicles16into and out of a charging station is also controlled by the planner100.

The planner100includes a path calculator102that calculates transportation paths for each of the vehicles16in the set of vehicles selected for fulfillment of an order. Each transportation path defines a sequence of markers20a-20dthat a vehicle16will follow in order to transport a rack12to a rack storage location in the goods storage area23and between the rack storage location and the operator station14. Calculated transportation paths for each vehicle16are stored in a defined paths database103. By one embodiment, the ‘cost’ of each defined transportation path is based on the time taken to travel from an initial source to a final destination. The calculation of a navigation path may further depend upon the lift state of the rack12. For instance, by one embodiment, if the lift state is up, then all other racks12are considered as obstacles along with the physical obstacles that may lie in the path. However, if the lift state is down, only the physical obstacles need to be considered.

According to one embodiment, the transportation paths for the vehicles16are computed using an A* algorithm. The algorithm uses the relationship between the markers20a-20d, which can be defined according to graph theory as illustrated inFIG. 6, to calculate an efficient path through the markers20a-20dfrom a source marker to a destination marker. An A* algorithm uses a best-first search and finds a least-cost path from a given initial node to one goal node chosen from one or more possible goals. As A* traverses a graph, it builds up a tree of partial paths. The leaves of the tree (referred to as an open set or the fringe) are stored in a priority queue that orders the leaf nodes by a cost function. It combines a heuristic estimate of the cost to reach a goal and the distance traveled from the initial node.

The cost function can be represented by f(n)=g(n)+h(n), wherein g(n) is the known cost of getting from the initial node to n, and this value is tracked by the algorithm. The parameter h(n) is a heuristic estimate of the cost to get from n to any goal node. For the algorithm to find the actual shortest path, the heuristic function must be admissible, meaning that it should not over estimate the actual cost to get to the nearest goal node. The heuristic function is problem-specific and is provided by the user of the algorithm.

The planner100also includes a vehicle navigator104that manages movements of each vehicle16individually according to the respective transportation paths defined for the vehicles16. The vehicle navigator104is responsible for controlling movement of a vehicle16along the sequence of markers20a-20din the transportation path, and handling communications received from the vehicles16.

As a vehicle16arrives at a marker20a-20d, the marker20a-20dis detected by the vehicle16and marker information, such as unique identification information associated with the detected marker20a-20dand/or a captured image of the marker, is communicated to the vehicle navigator104through the wireless communication network19. Based on the received information, the vehicle navigator104verifies that the identified marker20a-20dcorresponds to the expected marker20a-20din the transportation path, and communicates navigational information to the vehicle16in order to direct the vehicle16to a subsequent marker20a-20din the transportation path. In an example, the navigational information is in the form of a bearing value and a distance value derived from the navigational information stored in the marker database83and illustrated in tabular form inFIG. 7. That is, the vehicle navigator104sends navigational information to the vehicle16for each separate marker20a-20d(i.e., in a hop-by-hop basis, as stated previously).

The vehicle navigator104also calculates the position of a centroid of the vehicle16relative to a marker20a-20d, and the orientation of the vehicle16relative to the marker20a-20d. The position can be calculated using an image captured by a sensor and/or camera, such as the sensor/camera134illustrated inFIG. 9. The offset position of the vehicle16relative to a detected marker20a-20dcan be calculated there from with reference toFIG. 14. The current positions of the vehicles16are stored in a vehicle location database105. As a result, the planner100is aware of the locations of all vehicles16at all times.

In addition to navigating vehicles16along their paths, the vehicle navigator104also receives and processes messages from the vehicles16. By one embodiment, a first type of message received from a vehicle16is an initiate message. An initiate message is transmitted to the vehicle navigator104when a vehicle16starts up or reboots. The initiate message may be transmitted as a data packet that includes information corresponding to a scanned marker. If the scanned marker is a valid, the initiate message is processed by the vehicle manager110, which thereafter transmits navigational directions to the vehicle.

A second type of message received by the vehicle navigator104from a vehicle16is a warning message. A warning data packet is received by the vehicle navigator104when a vehicle16reaches a valid navigation marker which is not reserved for the vehicle16. In this situation, the navigation marker at which the vehicle16is located can be reserved and if possible, the next navigation marker in the navigation path is also reserved. However, if the current navigation marker is reserved by another vehicle16, the first vehicle16is stopped from travelling any further.

A third type of message received by the vehicle navigator104from a vehicle16is an information message. An information data packet is sent to the vehicle navigator104to update a position of a rack12if the vehicle16has lifted or is carrying a rack12. The vehicle navigator104informs pertinent personnel of a movement of the rack12and informs the vehicle manager110to check for any related tasks to be completed. An information packet can also un-reserve an old position if it exists and un-reserve turn reservations when they are completed. The vehicle navigator104updates vehicle16information in a relevant vehicle database, such as assigned vehicles database98, vehicle location database105, defined transportation paths database103, or reserved paths and markers database108. The vehicle navigator104can also determine if the destination navigation marker has been reached or if the next reservation navigation marker has been reached.

A fourth type of message received by the vehicle navigator104from a vehicle16is an error message. An error message is received by the vehicle navigator104when the barcode from an invalid navigation marker is read by the vehicle16. Error packets can also be sent to the vehicle navigator104when an instruction to the vehicle16cannot be processed by the vehicle16.

The vehicle navigator104can also be configured to manage movements of the vehicles16so that collisions are avoided. In one embodiment, collision management is achieved by managing the path and marker reservations, such that each navigation path between two markers (referred to herein as a segment) is reserved shortly before the vehicle16arrives. However, movement in a subsequent navigation path (i.e., a segment of the navigation path) is not allowed until the navigation path is reserved. If the navigation path is already reserved by another vehicle16, then the vehicle16wishing to reserve the navigation path enters a wait state. However, in certain embodiments, a previous reservation may be canceled, and rescheduled, based on priority information, for example when a particular order is assigned a higher priority than the order being fulfilled using the existing reservation. By one embodiment, specific paths in a particular section of the warehouse may be cleared for repair or support.

Further, it must be appreciated that since the end-to-end transportation path (i.e., from the source marker to the destination marker) for each vehicle16is not reserved at one time instant, there may be a deadlock situation, as two vehicles16may wish to move in opposite directions along similar paths. In order to resolve deadlocks, one of the vehicles16needs to move out of the way. Accordingly, the vehicle navigator104can be configured to actively control one of the vehicles16involved in the deadlock situation to move away from the designated path, thereby allowing the other vehicle16in the deadlock situation to move according to its designated transportation path.

By one embodiment, the vehicle navigator104can be configured to actively prevent deadlock situations from occurring. When the vehicle navigator104attempts to reserve a marker20a-20dfor a vehicle16, the vehicle navigator104checks whether another vehicle16also has a transportation path defined that passes through the marker20a-20d. If so, the vehicle navigator104reserves markers20a-20dfor the vehicle16as safety reservations. For markers20a-20dreserved as safety reservations, another vehicle16cannot reserve a marker20a-20din the safety reservations unless a marker20a-20dis also reserved that enables the other vehicle16to exit the safety reserved marker20a-20d. In other words, after a safety reservation has been made, no other vehicle16will be allowed to remain in the safety reserved region. Furthermore, collisions and deadlocks can be prevented by managing movements of the vehicles16based upon the reserved markers20a-20dand navigation paths, and by controlling the timing of movements of the vehicles16. As a result, collisions can be avoided by causing a vehicle16to wait, or by actively modifying the speed of movement of the vehicle16.

By an embodiment of the present disclosure, navigation variables can be used by the vehicle navigator104in processing a navigation path. A first variable referred to herein as a segment length variable corresponds to a length of the navigation path that is to be reserved for a vehicle16. A second variable referred to herein as reservation distance variable corresponds to the distance to the end of a navigation path. After a navigation path has been determined, a first segment length in the navigation path is reserved. The next segment, as well as the navigation marker at which the next reservation will be made is calculated. When the vehicle16reaches the next reservation position, another reservation distance is calculated. The above process continues until the vehicle16reaches its destination of the navigation path.

Furthermore, if there is a turn in a navigation path, a reservation distance is calculated for neighboring navigation markers. If a moving vehicle16or a turning vehicle16is found in a navigation path segment to be reserved, no reservation is made and a fail position is calculated. Additionally, by one embodiment, if an idle vehicle is disposed at the destination, the calculations cannot be completed. The vehicle16is either set to idle or it enters a wait state. By one embodiment, if an idle vehicle16is found in the segment to be reserved, a new path is calculated.

The planner100also includes a reservation manager106that manages reservations of markers20a-20dand navigation paths between markers20a-20dto avoid collisions between vehicles16. The planner100stores information indicative of the reserved markers20a-20dand navigation paths in a reserved paths and markers database108.

The planner100also includes a vehicle manager110that controls the vehicle's start and stop operations and control the movement of the contact plate36of the vehicle16between raised and lowered positions. The vehicle manager110also manages the charge level of the vehicles16, including checking the charge state of the vehicles16and managing movement of the vehicles16requiring charging to a vehicle charging station. Additionally, as shown inFIG. 8, the functional components of the block diagram81of the management system18may also include a network interface112, that facilitates networked communications between the management system18, the vehicles16, and the operator stations14.

Functional components118of a vehicle16, such as a transportation vehicle or transportation robot are illustrated inFIG. 9. The functional components118include a network interface120that facilitates networked communications between the vehicle16and each of the management system18and the operator stations14. A microcontroller122(implemented with circuitry, and described later with reference toFIG. 16) controls and coordinates operations in the vehicle16, and performs dedicated tasks such as managing detection of markers20a-20d, managing control of vehicle movement according to instructions received from the vehicle navigator104, and applying a compensation path, such as a recalculated navigation path using a Bezier curve, to the determined transportation path between markers20a-20d. The microcontroller122communicates with a motor driver124to control one or more motors126associated with the vehicle wheels34, and thereby control the speed and direction of the vehicle16.

The functional components118also include a lifting device130that controllably raises or lowers a contact plate36in response to instructions from the microcontroller122. Instructions from the microcontroller122can be generated in response to instructions received from the vehicle manager110.

The functional components118also include at least one sensor134, such as a camera or RFID reader, arranged to detect a marker20a-20dwhen the vehicle16travels close to the marker20a-20d. The sensor/camera134can obtain unique identification information that is associated with the marker20a-20d. The obtained unique identification information is communicated to the planner100by the microcontroller122so that the current location of the vehicle16can be determined.

The sensor(s)/camera134can also be used to determine an offset between a location of the vehicle16and a location of a detected marker20a-20d. The offset can be used to modify the transportation path defined between the detected marker20a-20dand a subsequent marker20a-20din the transportation path (described later with reference toFIG. 14). This is achieved by capturing an image, including the marker20a-20dand forwarding the image to the planner100for processing. In one embodiment, the offset is calculated by the vehicle16. Since the location and orientation of the captured image relative to the vehicle16is known, it is possible to determine the location and orientation of the marker20a-20drelative of the vehicle16.

The functional components118also include a weigher138that produces a weight measurement when the vehicle16is transporting a rack12. The weight measurement can be used by the microcontroller122to calculate movement parameters for a loaded vehicle16, such as appropriate acceleration and deceleration parameters in consideration of the weight of the rack12being transported by the vehicle16. The movement parameters can also be calculated based on whether the contact plate36is in a raised or lowered position.

The weigher138can also be used to determine a weight distribution profile by using the known centre of gravity of an empty rack12, the known weight of each goods item42, and the positions of the goods items42on the rack12. The weight distribution profile can be used to calculate the centre of gravity of the rack and loaded goods items42, which is then used to ensure that the centre of gravity of the loaded rack12is within a defined range. In doing so, it is ensured that the loaded rack12does not bounce too much during transportation.

By one embodiment, the z component of the centre of gravity of a loaded rack12can be manipulated by adjusting the locations of the goods items42on the rack12, in such a manner that the centre of gravity is not too high. It must be appreciated that the centre of gravity (COG) for the loaded rack can be computed based on a reference point on the rack and a distribution of goods items42on the rack12(i.e., the COG of each item). In addition, in relation to the x-y component of the centre of gravity, a cost value can be calculated for all goods item42receiving locations on the rack12, each time a goods item42is added to or removed from a rack12. The cost value may correspond to the amount by which the loaded rack12will deviate from the centre of gravity.

The microcontroller122may be configured to implement defined functionality in the vehicle16, including control of the motors126in response to instructions from the planner100, control of the lifting device130in response to instructions from the planner100, management of communications with the sensors/camera134and the weigher138, and management of communications to and from the network interface120.

Functional components139of an operator station14are illustrated inFIG. 10. The functional components139include a network interface140that facilitates networked communications between the operator station14, the management system18, and the vehicles16. A control unit142controls and coordinate operations in the operator station14. The control unit142is configured to implement defined functionality, such as an inward items process144and an outward items process146.

The inward items process144manages reception of new items of inventory into the goods handling system10, both in a physical sense and an electronic sense. In a physical sense, a new goods item42is disposed on a selected rack12, and the rack12is transported to a storage location in the goods storage area23. In an electronic sense, the presence and location of the goods item42is recorded in the inventory database86.

The outward items process146manages retrieval of goods items42from the goods handling system10, both in a physical sense and an electronic sense. In a physical sense, a goods item42forming part of an order is retrieved from a rack12in the goods storage area23. In an electronic sense, a record of the retrieved item is removed from the inventory database86.

The functional components139also include a pointing device50and a scanner52. The pointing device50operates in conjunction with the inward items process144and the outward items process146to coordinate retrieval of the correct goods item(s)42from the rack(s)12and placement of the goods items42at the correct locations on the rack(s)12. The scanner52is configured to scan identifiers on the goods items42, such as the barcodes on the goods items42, as they are picked from a rack12during order fulfillment or placed onto a rack12during addition of new inventory. The scanned barcodes enable the operator station14to check and verify whether the scanned goods item42is correct. In addition, or as an alternative to scanning the code, an object recognition device can be used to verify the scanned goods item42is correct.

FIG. 11depicts an exemplary flowchart160illustrating steps performed in an inventory process that is implemented by the goods handling system10.

New inventory of goods items42arrives at the warehouse in step162. For each goods item42received, an operator at an operator station14scans an identifier, such as a barcode on the goods item42, using the scanner52in step164. The operator station14communicates information indicative of the goods item42to the inventory manager84of the management system18. The inventory manager84adds a record of the goods item42to the inventory database86and communicates the desired location of the goods item42in the goods storage area23to the operator station14. For example, the rack12on which the goods item42should be stored and the location of placement of the goods item42on the rack12are communicated to the operator station14. In an embodiment, instructions can be given by the inventory manager84to change the placement of one or more goods items42to optimize organization of the total goods items42on the rack12.

Further, based upon the location communication received from the management system18, the inward items process144instructs a vehicle16to retrieve the relevant rack12from the goods storage area23in step166. After the rack12has been transported168to the operator station14, the pointing device50indicates the location on the rack12where the goods item42should be placed in step168. For example, a laser pointer can point at the location on the rack12in which the goods item42should be placed in step170.

In step172, it is determined whether another goods item42is to be stored on the same rack12. If another goods item42is to be placed on the same rack12, the additional goods item42is scanned and placed at a particular location on the rack12indicated to the operator by the pointing device50in step174. If no additional goods items42are to be placed on the same rack12, the rack12is transported back to a defined storage location in the goods storage area23in step176. It is determined whether there is an additional goods item42in the new inventory in step178. The process is repeated for each new inventory goods item42to be stored in the goods storage area23in step178. When there are no additional goods items42in the new inventory, the process ends at step180.

FIG. 12depicts a flow diagram190illustrating steps192to212of an item picking process implemented by the goods handling system10. By one embodiment, an order-processing server adds incoming orders to an order queue. An order is triggered for processing by the order manager90of the management system18in step192. The order-processing server determines the best set of racks (i.e., the racks having the smallest rack cost) to fulfil the order in the order queue. When the best set of racks has been determined, a task-assignment server calculates the best set of vehicles to carry the set of racks to the operator station14for an inventory retrieval process. A path-calculating server calculates the most efficient navigation paths for the selected vehicles in which there are no over-lapping regions within the navigation paths.

For a goods item42forming part of the order, the vehicle navigator104instructs a vehicle16to retrieve a selected rack12containing the goods item42in the order from the goods storage area23in step194. Step194can be achieved by successively communicating navigation instructions to the vehicle16to indicate successive navigation paths to travel between markers20a-20d. When the vehicle16reaches the selected rack12, the selected rack12is identified using the navigation marker under the selected rack12. The vehicle navigator104aligns the centroid of the vehicle with the centre of the selected rack12using data from the navigation marker to ensure the selected rack12is aligned during the rack lift and transport. The selected rack12is lifted from the ground by increasing the height of the lift head of the vehicle16. As an example, the selected rack is lifted approximately 5-10 cm from the ground for transport.

The vehicle16transports the selected rack12containing the goods item42to the operator station14in step196. The vehicles carry their selected racks12to the operator station14using previously-calculated acceleration and deceleration profiles for each associated vehicle16. When the selected rack12arrives at the operator station14in step198, control of each vehicle16is transferred to a queue management server. The queue management server moves the vehicles16in the order-processing queue. When the vehicle16has reached a pick point at the operator station14, a pointing device50points to the location on the rack12where the goods item42is to be located in step200. In an example, a laser pointer is directed at the location on the rack12.

The operator at the operator station14retrieves the identified goods item42from the rack12and scans an identifier located on the goods item42in step202. In response, the operator station14communicates information indicative of the goods item42to verify whether the correct goods item42has been selected in step204. If the item is verified as correct, the information indicative of the goods item42is also communicated to the inventory manager84of the management system18, which removes a record of the goods item42from the inventory database86.

In step206, it is determined whether another goods item42is stored on the same rack12. If an additional goods item42is to be picked from the same rack12, the pointing device50indicates the location on the rack12where the additional goods item42to be picked is located, and the above process is repeated for each additional goods item42.

Additionally, by one embodiment, goods items42on a rack may not be in an optimum arrangement. For example, added inventory of goods items42may have originally been placed in an optimum location. However, with further added inventory, the rack space may not be utilized to its fullest potential, or a centre of gravity may have shifted off balance. Therefore, the inventory manager84may send instructions to reorganize some or all of the goods items42on the rack12.

Further, if no further goods items42are to be picked from the same rack12, the rack12is transported back to a defined storage location in the goods storage area23in step208. In step210, it is determined whether there are additional goods items42in the order in step210. The process is repeated for each additional new goods item42in the order that is to be retrieved from the goods storage area23. When there are no additional goods items42in the order, the process ends at step212.

Turning now toFIGS. 13A and 13Bis depicted a flowchart220illustrating the steps performed in an order fulfillment process and control of vehicle movement.

Orders are received at the management system18using an order generator88, for example through an electronic commerce website in step222. The received orders are recorded in the orders database92by the order manager90and placed in an order queue in step224. In step226, it is determined whether an order has been triggered. When an order is triggered for fulfillment, the task manager96determines the preferred rack combination for fulfillment of the order based on the heuristic calculation described above in step228. The task manager96determines the best set of vehicles16to carry out retrieval of each of the determined racks12based on the locations of the vehicles16relative to the racks12in step230.

For each rack12in the rack combination, the path calculator102at the management system18calculates the transportation path to be followed by each vehicle16during retrieval of the racks12in step232. The transportation path of the vehicle16in going back to the goods storage area23is also determined. In an embodiment, the transportation paths are calculated using an A* algorithm. The transportation path defines the sequence of markers20a-20dthrough which a vehicle16will pass in order to travel from its current location to the relevant rack12in the goods storage area23, or the sequence of markers20a-20dthrough which a vehicle16will pass in order to travel from the goods storage area23to the operator station14.

For each vehicle16assigned to retrieve a rack12from the goods storage area23, the vehicle navigator104communicates navigation instructions to the vehicle16, which indicates a segmented navigation path to travel from the current marker20a-20dto a subsequent marker20a-20din the defined transportation path in step234. Such navigational information includes direction information, for example in the form of a bearing, and distance information indicative of the distance between the current marker20a-20dand the subsequent marker20a-20d. When the vehicle16arrives at the subsequent marker20a-20d, the vehicle16reads the unique identification information associated with the subsequent marker20a-20dusing the sensors134, and communicates the information indicative of the subsequent marker20a-20dto the vehicle navigator104in step236.

In step238, it is determined whether the vehicle16has arrived at the marker20bof the determined rack12to be retrieved. If the subsequent marker20a-20dis not the determined rack marker20b, the vehicle navigator104communicates further navigation instructions to the vehicle16, which indicates to the vehicle16how to travel from the current marker20a-20dto a further subsequent marker20a-20din the defined transportation path. This process continues until the subsequent marker20a-20dof the determined rack marker20bhas been reached. In the event a marker20a-20dis completely missed and a vehicle16is temporarily “lost,” the vehicle16can be instructed to stop and/or positional sensors on the vehicle16can be retrieved.

When the vehicle16arrives at the rack marker20bdisposed underneath the rack12to be retrieved, the position determiner132determines the position of the vehicle16relative to the rack12and if necessary, the vehicle16moves relative to the rack12in order to properly align the vehicle16with the rack12in step240. Sensors134on the vehicle16assist the position determiner132in properly aligning the vehicle16with the rack12. After alignment, the vehicle manager110sends a communication to the vehicle16to instruct the vehicle16to raise the rack12from the ground by raising the contact plate36from the lowered position to the raised position in step242.

The vehicle16moves towards the operator station14along a further defined transportation path. The vehicle navigator104communicates navigation instructions to the vehicle16, which indicates to the vehicle16how to travel from the current rack marker20bto a subsequent marker20a-20din the defined transportation path in step244. Navigational information can include direction information, for example in the form of a bearing, and distance information indicative of the distance between the current marker20a-20dand the subsequent marker20a-20d. When the vehicle16arrives at the subsequent marker20a-20d, the vehicle16reads the marker20a-20dand communicates the information indicative of the marker20a-20dto the vehicle navigator104in step246. In step248, it is determined whether the vehicle16has arrived at the queue entry marker20c. If the vehicle16has not arrived at the queue entry marker20c, the process continues until the subsequent marker20a-20dis a queue entry marker20c.

When the vehicle16arrives at a queue entry marker20c, control over movement of the vehicle16is transferred from the management system18to the operator station14in step250. The operator station14instructs the vehicles16and associated racks12in the station queue22to make sequential steps towards a pick point adjacent to an operator in step252. In step254, it is determined whether a vehicle16has arrived at the pick point. When a vehicle with a rack12arrives at the pick point, the pointing device50indicates the location on the rack where the goods item42to be picked is located in step256. This can be implemented by directing a laser pointer at the location on the rack12. The operator at the operator station14picks the goods item42and scan the goods item42in step258. The operator station14verifies whether the goods item42that has been picked from the rack12is correct in step260. If the goods item42is correct, the operator places the item in the assigned order bin46.

In step262, it is determined whether there are more goods items42to pick from the rack12. If there are more items to pick, the process is repeated for each additional goods item42to be picked from the same rack12. When no further goods items42are to be picked from the rack12, the vehicle16and rack12are controlled by the operator station and are moved towards a queue exit marker20dat an exit of the station queue22in step264. When the vehicle detects the queue exit marker20d, control over vehicle movement is transferred from the operator station14to the management system18in step266.

The vehicle navigator104communicates movement information to the vehicle16to indicate the direction and distance of movement to take from the current marker20a-20dto the next marker20a-20din step268. When the vehicle16arrives at a marker20a-20d, the vehicle16reads the marker20a-20dand communicates information indicative of the marker20a-20dto the vehicle navigator104in step270.

At step272, it is determined whether the vehicle16has arrived at a rack marker20b. If the vehicle16has not arrived at a rack marker20b, the process is repeated until a rack marker20bhas been reached. The vehicle16transports the rack12back to the relevant storage location in the goods storage area23. At the storage location in the goods storage area23, the vehicle manager110sends a communication to the vehicle16to instruct the vehicle16to lower the rack12to the ground by lowering the contact plate36in step274.

In step276, it is determined whether there are more goods items42to pick from other racks12. If additional goods items42from other racks12are included in the order, the process is repeated for transportation of each other rack12from the goods storage area23to the operator station14and back to the goods storage area23until all goods items42in the order are disposed in the order bin46. When all goods items42have been disposed in the order bin46, the order is finished in step278.

The process ofFIGS. 13A-13Bis illustrated for just one vehicle16for simplicity. However, in a working environment, several vehicles16can be operated simultaneously or in a successively-staggered operation by the vehicle navigator104to complete filling an order or completing an assignment.

FIG. 14is a diagram illustrating a methodology used for compensation of a navigation path of a vehicle.FIG. 14illustrates a vehicle16in an adjacent proximity to a first marker282. The vehicle16is travelling towards a second subsequent marker284. The navigation path285in the illustration is a straight line between the first marker282and the second marker284.

As illustrated inFIG. 14, the centroid286of vehicle16is offset from the first marker282by a distance of √{square root over ((ΔX)2+(ΔY)2)}, wherein ΔX is the offset along a first axis (x-axis), and ΔY is the offset along a second axis (y-axis). In order to compensate for the offset, a correction path288is defined that extends between the centroid286and the navigation path285.

In an embodiment, the correction path288to apply to the uncorrected navigation path285is calculated using the offset distance ΔX of the centroid286from the first marker282along the x-axis and the offset distance ΔY of the centroid286from the first marker282along the y-axis. Furthermore, the difference in the direction vectors (i.e., angular difference) of the transportation vehicle16and the uncorrected navigation path285(illustrated as Vf) is illustrated as an angle theta from the uncorrected navigation path285. The angle theta is also used to calculate the correction path288. By one embodiment, the correction path288is a Bezier curve that is generated based on the above stated information.

According to one embodiment, the correction path288may be calculated from a cumulative velocity profile. A cumulative velocity profile can consider certain variables, such as whether a vehicle16is carrying a rack12and if so, the weight of the rack12. Note that if the vehicle16is carrying a rack12, the correction path288needs to consider any other racks12within the navigation path as obstacles, as well as consider any other physical obstacles that may lie in the navigation path. If the vehicle16is not carrying a rack12, only physical obstacles need to be considered.

By one embodiment, another variable considered in the computation of a compensation path is the number of marker segments that are to be traversed in a navigation path. As described below, from these variables, as well as other relevant variables, an acceleration distance and rate of acceleration, as well as a deceleration distance and a rate of deceleration can be computed. In an embodiment, a degree of acceleration per unit time, as well as a degree of deceleration per unit time can be obtained. For instance, a three-degree of acceleration and deceleration per unit time may be plotted. However, other degree amounts can be used to plot the acceleration and deceleration per unit time. Accordingly, the cumulative velocity profile can be obtained from the calculated acceleration profile, the deceleration profile, and a constant velocity profile. Application of the calculated cumulative velocity profile can result in a 3-degree Bezier curve. Thus, the Bezier curve can be the reference for movement of a projected centre of mass point of the vehicle on the ground to obtain the correction path288. The above process is repeated as the vehicle16reaches a new marker20a-20don its navigation path.

By one embodiment, the navigation path between adjacent markers282and284is divided into a plurality of segments. In an example, the navigation path between two adjacent markers can be divided into five hundred segments. As movement of the vehicle16commences, a timer and a wheel counter are initiated. A wheel counter measures the amount of rotation about each wheel of a vehicle16. The combined wheel rotations can identify the direction and distance traveled by the vehicle16.

Furthermore, a segment counter maintains a record of the current segment. The respective velocities of the wheels34can be set at the start of each segment. After a pre-determined time, such as every 500 μs, the timer is interrupted and the wheel count is read. If the wheel count is at least equal to an expected count, the segment counter is incremented. After a defined amount of the corrected navigation path has been completed, for example approximately 95% of the corrected navigation path, the vehicle16is instructed by the vehicle navigator104to attempt to detect the second marker284.

By one embodiment, the calculations can be performed by considering the following parameters: let parameter NoM correspond to the number of steps (i.e., markers) to be traversed in a straight path (note that NoM is at least one), parameter X be a constant corresponding to acceleration distance (e.g., let X be assigned a value 120), parameter Y be a constant corresponding to deceleration distance (e.g., let Y be assigned a value 120), the parameter start_speed be assigned a value of 15, the parameter max speed be assigned a value of 100, and the parameter stop_speed be assigned a value of 7.

An initial acceleration-deceleration profile is determined by computing an acceleration distance (AD), deceleration distance (DD), and maximum speed (MS) as follows:
AD=minimum(X,X*0.5*NoM)  (2)
DD=minimum(Y,Y*0.5*NoM)  (3)
MS=minimum(max speed,start_speed*(4*NoM))  (4)
Thus, by one embodiment, the acceleration-deceleration profile is computes based on the number of markers that are traversed in a straight line.

Further, in order to generate a compensation curve, the distance between the two markers (e.g., distance between the markers282and284) is divided into a predetermined number of segments. Additionally, a predetermined number of interpolation points are selected. By one embodiment, four interpolation points are selected. Note that the number of points selected affects the smoothness of the compensation curve. It must be appreciated that embodiments described herein are in no manner limited to the selection of four interpolation points and any other number of interpolation points may be selected.

By one embodiment, the first interpolation point is assigned the coordinates of the offset position of the center of gravity of the vehicle, and the fourth coordinate point is assigned the coordinate of the second marker. Additionally, the coordinates for the intermediate interpolation points can be computed based on the initial offsets ΔX and ΔY, the initial angular difference (theta), and the distance between the markers. Upon computing the coordinates of interpolation points, a compensation curve such as Bezier curve can be generated. Further, upon the vehicle traversing each segment, the acceleration-deceleration profile can be modified based on wheel counter. Further, while adjusting the speed of the vehicle at each segment, by one embodiment, both linear and turning speeds of the vehicles are taken into account, as well as the determination of whether the vehicle is carrying a rack and the associated weight profile of the rack are taken into account.

By one embodiment of the present disclosure, the offset distances ΔX, ΔY of the centroid286from the first marker282are calculated by the vehicle navigator104. The offset distances ΔX, ΔY are based on an image captured by the sensor/camera134in the vehicle16, wherein the captured image includes the first marker282. The location and orientation of the sensor/camera134relative to the vehicle16can be determined using a jig, for example. A permanent offset is calculated that represents the default distance between the centre of the vehicle16and the centre of the image captured by the sensor/camera134.

The location and orientation of the first marker282in the captured image may be determined using image processing techniques. The centroid of the first marker282is calculated, and the offset between the first marker282and the centre of the vehicle16is determined. In this example, the location and orientation of the first marker282is determined using OpenCV image processing algorithms, although it will be understood that any suitable image processing techniques can be used.

Further, the coordinates of the corners of the first marker282and the coordinates of the centre of the first marker282can be determined using OpenCV function ‘minAreaRect’. The corner coordinates are used to determine the angle of rotation of the vehicle16with respect to the first marker282. The distance between the centre of the first marker282and the centre of the captured image represents the offset distances ΔX, ΔY.

By one embodiment, the offset distance can be determined using suitable sensors, such as a plurality of lasers that are used to measure distance, wherein the position of the centroid of the vehicle16relative to the marker20is calculated using triangulation techniques. However, other relative position determining arrangements can be used. Furthermore, the vehicle navigator104can also be arranged to calculate speed and acceleration information for movement of the vehicle16, based on the transportation path to be followed by the vehicle16and based on the offset position of the vehicle16from the detected marker20a-20d. The calculated speed, acceleration, and direction information are communicated to the motor driver124during movement of the vehicle16.

FIG. 15depicts an exemplary flowchart1500depicting the steps performed in path correction according to an embodiment. The path correction steps as depicted inFIG. 15are illustrated for the case of a vehicle traversing from a first marker to a second marker, and wherein the vehicle has an offset at the first marker.

In step1501, the offset between the centroid of the vehicle and the first marker is computed. As stated previously, by one embodiment, the offset (ΔX, ΔY) may be computed based on an image captured by a sensor/camera that is disposed in the vehicle16, wherein the captured image includes the first marker.

In step1503, the distance between the first marker and the second marker is divided into a predetermined number of segments. By one embodiment, the distance between the markers is divided into 500 segments.

Further, in step1507, an initial acceleration-deceleration profile based on the distance to be traversed in a straight path is computed. In the present example, the distance corresponds to the distance between the first marker and the second marker. Note however, that the distance may correspond to the number of markers that are to be traversed in a straight path. The acceleration-deceleration profile can be computed as stated previously in equations (2)-(4).

In step1509, a predetermined number of interpolation points are selected. Further, as stated previously, coordinates for each of the interpolation points are computed based on an angular deviation of the vehicle and the distance between the first and second markers. The process in1511generates a compensation curve based on the computed offset in1501and the computed coordinates of the interpolation points in1509.

Further, the process1500in step1513modifies the acceleration-deceleration profile of the vehicle after the vehicle has traversed a segment interval. For instance, by one embodiment, upon the vehicle traversing a segment, the speed of the vehicle is adjusted based on a wheel counter that measures the amount of rotation about each wheel of the vehicle. The combined wheel rotations correspond to the direction and distance traveled by the vehicle. In this manner, the process1500generates a compensation path for a vehicle that is offset at the first marker, thereby ensuring that the vehicle is positioned above the second marker when the vehicle commences traversing the distance between the markers. Nonetheless, it must be appreciated that in case the vehicle is not positioned exactly over the second marker, the process of1500can be repeated in order to provide further path correction.

Each of the functions of the described embodiments may be implemented by one or more processing circuits. A processing circuit includes a programmed processor (for example, processor1603inFIG. 16), as a processor includes circuitry. A processing circuit also includes devices such as an application-specific integrated circuit (ASIC) and circuit components that are arranged to perform the recited functions.

The various features discussed above may be implemented by a computer system (or programmable logic).FIG. 16illustrates such a computer system1601. In one embodiment, the computer system1601is a particular, special-purpose machine when the processor1603is programmed to perform navigational processes of the vehicle, computing compensation path, and other functions described above.

The computer system1601includes a disk controller1606coupled to the bus902to control one or more storage devices for storing information and instructions, such as a magnetic hard disk1607, and a removable media drive1608(e.g., floppy disk drive, read-only compact disc drive, read/write compact disc drive, compact disc jukebox, tape drive, and removable magneto-optical drive). The storage devices may be added to the computer system1601using an appropriate device interface (e.g., small computer system interface (SCSI), integrated device electronics (IDE), enhanced-IDE (E-IDE), direct memory access (DMA), or ultra-DMA).

The computer system1601may also include a display controller1609coupled to the bus902to control a display1610, for displaying information to a computer user. The computer system includes input devices, such as a keyboard1611and a pointing device1612, for interacting with a computer user and providing information to the processor1603. The pointing device1612, for example, may be a mouse, a trackball, a finger for a touch screen sensor, or a pointing stick for communicating direction information and command selections to the processor1603and for controlling cursor movement on the display1610.

The processor1603executes one or more sequences of one or more instructions contained in a memory, such as the main memory1604. Such instructions may be read into the main memory1604from another computer readable medium, such as a hard disk1607or a removable media drive1608. One or more processors in a multi-processing arrangement may also be employed to execute the sequences of instructions contained in main memory1604. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions. Thus, embodiments are not limited to any specific combination of hardware circuitry and software.

Stored on any one or on a combination of computer readable media, the present disclosure includes software for controlling the computer system1601, for driving a device or devices for implementing the features of the present disclosure, and for enabling the computer system1601to interact with a human user. Such software may include, but is not limited to, device drivers, operating systems, and applications software. Such computer readable media further includes the computer program product of the present disclosure for performing all or a portion (if processing is distributed) of the processing performed in implementing any portion of the present disclosure.

The computer code devices of the present embodiments may be any interpretable or executable code mechanism, including but not limited to scripts, interpretable programs, dynamic link libraries (DLLs), Java classes, and complete executable programs. Moreover, parts of the processing of the present embodiments may be distributed for better performance, reliability, and/or cost.

The term “computer readable medium” as used herein refers to any non-transitory medium that participates in providing instructions to the processor1603for execution. A computer readable medium may take many forms, including but not limited to, non-volatile media or volatile media. Non-volatile media includes, for example, optical, magnetic disks, and magneto-optical disks, such as the hard disk1607or the removable media drive1608. Volatile media includes dynamic memory, such as the main memory1604. Transmission media, on the contrary, includes coaxial cables, copper wire and fiber optics, including the wires that make up the bus902. Transmission media also may also take the form of acoustic or light waves, such as those generated during radio wave and infrared data communications.

Various forms of computer readable media may be involved in carrying out one or more sequences of one or more instructions to processor1603for execution. For example, the instructions may initially be carried on a magnetic disk of a remote computer. The remote computer can load the instructions for implementing all or a portion of the present disclosure remotely into a dynamic memory and send the instructions over a telephone line using a modem. A modem local to the computer system1601may receive the data on the telephone line and place the data on the bus902. The bus902carries the data to the main memory1604, from which the processor1603retrieves and executes the instructions. The instructions received by the main memory1604may optionally be stored on storage device1607or1608either before or after execution by processor1603.

The computer system1601also includes a communication interface1613coupled to the bus902. The communication interface1613provides a two-way data communication coupling to a network link1614that is connected to, for example, a local area network (LAN)1615, or to another communications network1616such as the Internet. For example, the communication interface1613may be a network interface card to attach to any packet switched LAN. As another example, the communication interface1613may be an integrated services digital network (ISDN) card. Wireless links may also be implemented. In any such implementation, the communication interface1613sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information.

The network link1614typically provides data communication through one or more networks to other data devices. For example, the network link1614may provide a connection to another computer through a local network1615(e.g., a LAN) or through equipment operated by a service provider, which provides communication services through a communications network1616. The local network1614and the communications network1616use, for example, electrical, electromagnetic, or optical signals that carry digital data streams, and the associated physical layer (e.g., CAT 5 cable, coaxial cable, optical fiber, etc.). The signals through the various networks and the signals on the network link1614and through the communication interface1613, which carry the digital data to and from the computer system1601may be implemented in baseband signals, or carrier wave based signals.

The baseband signals convey the digital data as unmodulated electrical pulses that are descriptive of a stream of digital data bits, where the term “bits” is to be construed broadly to mean symbol, where each symbol conveys at least one or more information bits. The digital data may also be used to modulate a carrier wave, such as with amplitude, phase and/or frequency shift keyed signals that are propagated over a conductive media, or transmitted as electromagnetic waves through a propagation medium. Thus, the digital data may be sent as unmodulated baseband data through a “wired” communication channel and/or sent within a predetermined frequency band, different than baseband, by modulating a carrier wave. The computer system1601can transmit and receive data, including program code, through the network(s)1615and1616, the network link1614and the communication interface1613. Moreover, the network link1614may provide a connection through a LAN1615to a mobile device1617such as a personal digital assistant (PDA) laptop computer, or cellular telephone.

It must be appreciated that embodiments are described herein for a vehicle, such as a transportation vehicle or a transportation robot. However, embodiments described herein can be applied to other automatically guided vehicles. Examples include, but are not limited to a four-wheel drive vehicle, or a vehicle using an Ackerman steering system in which the front inside wheel turns into a curve at a greater radius than the front outside wheel.

While aspects of the present disclosure have been described in conjunction with the specific embodiments thereof that are proposed as examples, alternatives, modifications, and variations to the examples may be made. It should be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

Furthermore, the foregoing discussion discloses and describes merely exemplary embodiments of the present invention. As will be understood by those skilled in the art, the present disclosure may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the present disclosure is intended to be illustrative and not limiting of the scope, as well as the claims. The disclosure, including any readily discernible variants of the teachings herein, defines in part, the scope of the foregoing claim terminology such that no subject matter is dedicated to the public. Additionally, the above disclosure also encompasses the embodiments listed below:

(1) A goods handling system comprising: a plurality of markers, each marker having associated unique identification information; at least one vehicle, each vehicle including at least one sensor arranged to detect a marker and obtain the unique identification information associated with the marker, and each vehicle arranged to controllably transport items between defined locations; and a data storage device including information indicative of each marker and navigational information associated with each marker, the navigational information indicative of the location of at least one defined other marker relative to the marker, and the navigational information usable to control movement of a vehicle between the marker and the at least one defined other marker; wherein the system is arranged to define a transportation path between defined locations, the transportation path defined by a plurality of selected markers, and the system arranged to control movement of a vehicle between the defined locations by using the navigational information associated with each marker.

(2) The goods handling system of (1), wherein each marker comprises a machine readable pattern.

(3) The goods handling system of (2), wherein the machine readable pattern includes a barcode or QR code.

(4) The goods handling system of (1), wherein each marker comprises a RFID device.

(5) The goods handling system of (1)-(4) comprising at least one operator station, wherein the system is arranged to controllably move each vehicle to and from an operator station.

(6) The goods handling system of (5), wherein the operator station includes a station queue, and wherein each vehicle arriving at the operator station enters the station queue, one or more items being placed on the rack or removed from the rack when the vehicle is in the station queue.

(7) The goods handling system of (6), wherein the markers include at least one queue entry marker disposed adjacent an entry location of the station queue, and at least one queue exit marker disposed adjacent an exit location of the station queue.

(8) The goods handling system of (5)-(7), wherein the system includes a plurality of item racks and each vehicle is arranged to controllably transport a rack to and from an operator station.

(9) The goods handling system of (8), wherein the markers include rack markers, each rack marker disposed adjacent or under a rack when the rack is disposed at a rack storage location.

(10) The goods handling system of (8), wherein the markers include rack markers disposed on respective racks.

(11) The goods handling system of (1)-(10), wherein the markers include warehouse markers disposed between a rack storage location and the at least one operator station.

(12) The goods handling system of (1)-(11), wherein each vehicle includes a contact member and a lifting device arranged to controllably raise or lower the contact member relative to the ground.

(13) The goods handling system of (1)-(12), comprising a management system in wireless communication with the vehicles, the management system arranged to provide the instructions to control movement of a vehicle between the defined locations by using the navigational information associated with each marker.

(14) The goods handling system of (5), wherein the system is arranged to transfer control of movement of a vehicle to the operator station when the vehicle is in the station queue.

(15) The goods handling system of (1)-(14), wherein the navigational information defines a navigation path between markers in a transportation path, the system arranged to determine an offset displacement between the vehicle and an adjacent marker, and the system arranged to use the determined offset displacement to calculate a compensation path, the compensation path modifying the navigation path to produce a compensated navigation path used to control movement of the vehicle between the markers.

(16) The goods handling system of (15), wherein the compensation path is a Bezier curve.

(17) The goods handling system of (15)-(16), wherein the navigation path is divided into a plurality of path segments, and the system is arranged such that instructions to control movement of the vehicle are provided at the start of each path segment.

(18) The goods handling system of (15) to (17), wherein the system is arranged to determine an offset displacement between the vehicle and an adjacent marker by capturing an image that includes the adjacent marker and processing the image to determine the distance between a centroid of the adjacent marker and a centroid of the captured image.

(19) The goods handling system of (18), wherein the image is processed so as to determine the coordinates of the corners of the adjacent marker, the corner coordinates being used to determine the angle of rotation of the adjacent marker.

(20) The goods handling system of (1)-(19), wherein the velocity of a vehicle is dependent on whether the vehicle is loaded.

(21) The goods handling system of (20), wherein each vehicle includes a weighing device arranged to weigh an item transported by the vehicle, the velocity of the vehicle being dependent on the weight.

(22) The goods handling system of (1)-(21), wherein the system is arranged to determine a weight distribution profile by using the known centre of gravity of an empty rack, the known weight of each transported item and the positions of the transported items on the rack.

(23) The goods handling system of (22), wherein the weight distribution profile is used to calculate the centre of gravity of the rack and loaded items, and to determine whether the centre of gravity of the loaded rack is within a defined range.

(24) The goods handling system (1)-(23), wherein the navigational information comprises a displacement value and a bearing value.

(25) The goods handling system of (1)-(24), wherein the system is arranged to store information indicative of the locations of all vehicles relative to the markers.

(26) The goods handling system of (1)-(25), wherein the system is arranged to store inventory information indicative of all items associated with the goods handling system including the respective racks on which the items are located and the locations on the racks where the items are located.

(27) The goods handling system of (1) to (26), comprising an order manager arranged to manage timing of order processing.

(28) The goods handling system of (27), wherein the order manager is arranged prioritise order processing based on the expected time taken to fulfil the order.

(29) The goods handling system of (27) or (28), wherein the order manager is arranged to determine a combination of racks to use to fulfil an order using the following heuristic: Heuristic, H=Distance/(1+No of Common Racks), where Distance is the combined distance of all racks in a rack combination from an available order bin, and No of Common Racks is the number of racks in the rack combination that are common to more than one rack set.

(30) The goods handling system of (1)-(29), wherein the system comprises a task manager arranged to determine a set of vehicles to use to fulfil an order.

(31) The goods handling system of (1)-(30), comprising a path calculator arranged to calculate a transportation path for each vehicle in the selected set of vehicles.

(32) The goods handling system of (31), wherein the transportation path is calculated using an A* algorithm.

(33) The goods handling system of (1)-(32), comprising a vehicle navigator arranged to manage movement of each vehicle individually.

(34) The goods handling system of (33), wherein the vehicle navigator is arranged to receive the unique identification information associated with a detected marker from a vehicle, and in response to communicate the navigational information associated with the detected marker to the vehicle.

(35) The goods handling system (1)-(34), wherein the system is arranged to manage movements of the vehicles so as to avoid collisions between the vehicles.

(36) The goods handling system of (35), wherein the system is arranged to reserve markers and/or navigation paths, manage the timing or movements and/or speed of the vehicles, and/or control vehicles so as to move temporarily outside the transportation path.

(37) A method of handling goods, the method comprising: disposing a plurality of markers in a defined area, each marker having associated unique identification information; providing at least one vehicle, each vehicle including at least one sensor arranged to detect a marker and obtain the unique identification information associated with the marker, and each vehicle arranged to controllably transport items between defined locations; and storing information indicative of each marker and navigational information associated with each marker, the navigational information indicative of the location of at least one defined other marker relative to the marker, and the navigational information usable to control movement of a vehicle between the marker and the at least one defined other marker; defining a transportation path between defined locations, the transportation path defined by a plurality of selected markers; and controlling movement of a vehicle between the defined locations by using the navigational information associated with each marker.

(38) The method of (37), wherein each marker comprises a machine readable pattern.

(39) The method of (38), wherein the machine readable pattern includes a barcode or QR code.

(40) The method of (38), wherein each marker comprises a RFID device.

(41) The method of (37)-(40), comprising providing a management system in wireless communication with the vehicles, and providing instructions from the management system to control movement of a vehicle between the defined locations using the navigational information associated with each marker.

(42) The method of (37)-(41), comprising providing at least one operator station having a station queue, controlling each vehicle to move to and from an operator station, and transferring control of movement of a vehicle to the operator station when the vehicle is in the station queue.

(43) The method of (37)-(42), wherein the navigational information defines a navigation path between markers in a transportation path, the method comprising determining an offset displacement between the vehicle and an adjacent marker, using the determined offset displacement to calculate a compensation path, and using the compensation path to modify the navigation path to produce a compensated navigation path used to control movement of the vehicle between the markers.

(44) The method of (43), wherein the compensation path is a Bezier curve.

(45) The method (43) or (44) comprising dividing the navigation path into a plurality of path segments, and providing instructions to control movement of the vehicle at the start of each path segment.

(46) The method as (43)-(45), comprising determining an offset displacement between the vehicle and an adjacent marker by capturing an image that includes the adjacent marker and processing the image to determine the distance between a centroid of the adjacent marker and a centroid of the captured image.

(47) The method of (46), comprising processing the image so as to determine the coordinates of the corners of the adjacent marker, and using the corner coordinates to determine the angle of rotation of the adjacent marker.

(48) The method of (37)-(47), comprising determining a weight distribution profile by using the known centre of gravity of an empty rack, the known weight of each transported item and the positions of the transported items on the rack.

(49) The method of (48), comprising using the weight distribution profile to calculate the centre of gravity of the rack and loaded items, determining whether the centre of gravity of the loaded rack is within a defined range.

(50) The method of (37)-(49), comprising storing information indicative of the locations of all vehicles relative to the markers.

(51) The method of (37)-(50), comprising prioritising order processing based on the expected time taken to fulfil the order.

(52) The method of (37)-(51), comprising determining a combination of racks to use to fulfil an order using the following heuristic: Heuristic, H=Distance/(1+No of Common Racks), where Distance is the combined distance of all racks in a rack combination from an available order bin, and No of Common Racks is the number of racks in the rack combination that are common to more than one rack set.

(53) The method of (52), comprising calculating the transportation path using an A* algorithm.

(54) The method as claimed of (37)-(53), comprising managing movements of the vehicles so as to avoid collisions between the vehicles by reserving markers and/or navigation paths, managing the timing or movements and/or speed of the vehicles, and/or controlling vehicles so as to move temporarily outside the transportation path.

(55) A navigation system for navigating a vehicle, the system comprising: at least one sensor arranged to detect a marker adjacent the sensor; the system arranged to use navigational information indicative of the location of at least one defined other marker relative to the detected marker to control movement of the vehicle along a navigation path between the detected marker and the other marker; and the system arranged to determine an offset displacement between the vehicle and the detected marker, and to use the determined offset displacement to calculate a compensation path, the compensation path modifying the navigation path to produce a compensated navigation path used to control movement of the vehicle between the markers; wherein the compensation path comprises a Bezier curve.

(56) The navigation system of (55), wherein the navigation path is divided into a plurality of path segments and the system is arranged such that instructions to control movement of the vehicle are provided at the start of each path segment.

(57) The navigation system of (55) or (56), wherein the system is arranged to determine an offset displacement between the vehicle and an adjacent marker by capturing an image that includes the adjacent marker and processing the image to determine the distance between a centroid of the adjacent marker and a centroid of the captured image.

(58) The navigation system of (57), wherein the image is processed so as to determine the coordinates of the corners of the adjacent marker, the corner coordinates being used to determine the angle of rotation of the adjacent marker.