U.S. patent application number 12/074283 was filed with the patent office on 2008-06-26 for inventory replication based upon order fulfillment rates.
Invention is credited to Gautam Bhargava, Peter Ham, Radhakrishna Hari, Boris Klots, Franklin R. Koenig, Gerry Perham.
Application Number | 20080154709 12/074283 |
Document ID | / |
Family ID | 39332445 |
Filed Date | 2008-06-26 |
United States Patent
Application |
20080154709 |
Kind Code |
A1 |
Ham; Peter ; et al. |
June 26, 2008 |
Inventory replication based upon order fulfillment rates
Abstract
A load balancing technology segregates various inventory types
(e.g., potatoes vs. milk, vs. pretzels, vs. tissue paper, etc.)
based upon how frequently they are ordered in a distribution
center. Inventory types that are ordered at the slowest rate are
not "replicated" over multiple pods in the distribution center.
Rather, they are constrained to reside at a single pod within the
distribution center. Items that are ordered somewhat more
frequently than those in the slowest group are replicated in
multiple pods across the distribution center. In other words, these
items are separately stocked at locations on more than one pod in
the distribution center. This means that a container passing
through the distribution center can obtain each of the items in the
second group of item types at multiple pods in the distribution
center. Thus, these items do not create a bottleneck in the order
fulfillment process. Inventory types in a third group, the fastest
movers, are segregated from items in the first two groups. They are
stored in a separate type of pod that fulfills orders even faster
than the other type of pods.
Inventors: |
Ham; Peter; (Palo Alto,
CA) ; Klots; Boris; (Belmont, CA) ; Hari;
Radhakrishna; (Belmont, CA) ; Koenig; Franklin
R.; (Palo Alto, CA) ; Bhargava; Gautam;
(Cupertino, CA) ; Perham; Gerry; (San Francisco,
CA) |
Correspondence
Address: |
IPVENTURE, INC.
5150 EL CAMINO REAL, SUITE A-22
LOS ALTOS
CA
94022
US
|
Family ID: |
39332445 |
Appl. No.: |
12/074283 |
Filed: |
March 3, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09568570 |
May 10, 2000 |
7370005 |
|
|
12074283 |
|
|
|
|
60133646 |
May 11, 1999 |
|
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Current U.S.
Class: |
705/7.25 ;
705/7.29 |
Current CPC
Class: |
G06Q 30/0601 20130101;
G06Q 30/0617 20130101; G06Q 10/06375 20130101; G06Q 30/0633
20130101; G06Q 30/0201 20130101; G06Q 10/087 20130101; G06Q
10/06315 20130101 |
Class at
Publication: |
705/10 |
International
Class: |
G06F 17/00 20060101
G06F017/00; G06Q 10/00 20060101 G06Q010/00 |
Claims
1. A computer-implemented method for managing an on-line store,
including distributing inventory to facilitate order throughput in
a distribution center that has a plurality of storage areas, the
method comprising: determining, by a computing device, how rapidly
a product is consumed based on order information of a plurality of
customers over a period of time to assist with distributing the
product in one or more of the storage areas in the distribution
center; allowing a customer to access information regarding the
product via a computer interface of the on-line store; receiving a
current order from the customer via the computer interface, wherein
the current order having an order status; providing to the customer
an order history of the customer via the computer interface from a
database accessible by the computer-interface, in view of a request
from the customer; allowing the customer to access at least one
attribute of the order status of the customer's current order via
the computer interface of the on-line store, the order status
depending on a status of at least one product in the distribution
center; allowing a representative of the on-line store to access
the customer's order history from a database accessible by a
customer relationship management system; and allowing the
representative to enter information related to the customer to the
database accessible by the customer relationship management system,
and wherein information from the database accessible by the
computer interface and information from the database accessible by
the customer relationship management system are transmitted to a
data warehouse system.
2. The method of claim 1, wherein the distribution system has a
management system, wherein the management system of the
distribution center manages the movement of a plurality of
conveyors in the distribution center, and wherein at least one
conveyor is configured to move a container to a storage area to
allow a product in the container to be stored in the storage
area.
3. The method of claim 1, wherein the distribution system has a
management system, wherein the management system of the
distribution center manages the movement of a conveyor in the
distribution center, wherein the management system of the
distribution center manages the movement of a carousel in the
distribution center to store different products, and wherein the
carousel is configured to be proximate to the conveyor to assist
moving products from the conveyor to be stored in the carousel.
4. The method of claim 1, wherein the distribution system has a
management system, wherein the management system of the
distribution center manages the movement of a plurality of
carousels in the distribution center to store different products,
wherein a storage area is configured to have a plurality of
carousels, and wherein the management system of the distribution
center can determine to store the product in each of the plurality
of the carousels of the storage area.
5. The method of claim 1, wherein the distribution system has a
management system, and wherein the management system of the
distribution center determines whether a product is to be stored in
one storage area or is to be stored in more than one storage area
of the distribution center based on how rapidly the product is
consumed.
6. The method of claim 1, wherein the representative of the on-line
store accesses the customer's order history while addressing a
request from the customer.
7. The method of claim 1 further comprising allowing the
representative to cancel the customer's current order.
8. The method of claim 1 further comprising allowing the
representative to issue credits via the customer relationship
management system, in view of a customer complaint.
9. The method of claim 1 further comprising allowing the
representative to process a customer-reported short in delivery via
the customer relationship management system.
10. The method of claim 1, wherein the data warehouse system
includes a data store and a data warehouse, wherein the data
warehouse system stores the received information from the database
accessible by the computer-interface and the received information
from the database accessible by the customer relationship
management system in the data store, and wherein the data warehouse
includes tables derived from information in the data store.
11. The method of claim 1 further comprising allowing the data
warehouse system to query the database accessible by the customer
interface for a current status regarding the computer interface of
the on-line store.
12. The method of claim 11, wherein the data warehouse system is
configured to report on the current status regarding the computer
interface of the on-line store in a minute-to-minute manner.
13. The method of claim 1 wherein the data warehouse system is
configured to generate reports, with at least one report on daily
and weekly activities of the on-line store based on information
from the database accessible by the customer relationship
management system and from the database accessible by the computer
interface.
14. The method of claim 13, wherein at least one report is on
customer order activities.
15. The method of claim 1, wherein the customer is allowed to
create a shopping list at the on-line store with at least one
attribute of the shopping list customizable by the customer.
16. The method of claim 15, wherein based on information regarding
the customer, the computer interface retrieves a preference of the
customer to present customized information to the customer.
17. The method of claim 1, wherein based on information regarding
the customer, the computer interface retrieves a preference of the
customer to present customized information to the customer.
18. The method of claim 1, wherein the representative is allowed to
access the customer's order history via a handheld mobile device to
fulfill the current order of the customer.
19. The method of claim 18, wherein the handheld mobile device
includes a scanner that allows the representative to scan an
identification of a product in the current order of the
customer.
20. A computer-readable medium containing instruction for
controlling a computer system to manage an on-line store, including
distributing inventory to facilitate order throughput in a
distribution center that has a plurality of storage areas, by a
method comprising: determining how rapidly a product is consumed
based on order information of a plurality of customers over a
period of time to assist with distributing the product in one or
more of the storage areas in the distribution center; allowing a
customer to access information regarding the product via a computer
interface of the on-line store; receiving a current order from the
customer via the computer interface, wherein the current order
having an order status; providing to the customer an order history
of the customer via the computer interface from a database
accessible by the computer-interface, in view of a request from the
customer; allowing the customer to access at least one attribute of
the order status of the customer's current order via the computer
interface of the on-line store, the order status depending on a
status of at least one product in the distribution center; allowing
a representative of the on-line store to access the customer's
order history from a database accessible by a customer relationship
management system; and allowing the representative to enter
information related to the customer to the database accessible by
the customer relationship management system, and wherein
information from the database accessible by the computer interface
and information from the database accessible by the customer
relationship management system are transmitted to a data warehouse
system.
21. A method of distributing inventory to facilitate order
throughput in a distribution center, the method comprising: for
each type of inventory to be distributed by the method, determining
how rapidly that type of inventory is consumed; identifying a first
group of inventory types that are relatively slower moving types of
inventory and distributing the inventory types from the first group
over multiple pods in a distribution center without replicating a
given inventory type in more than one pod; and identifying a second
group of inventory types that are relatively faster moving types of
inventory and replicating inventory types from the second group at
multiple pods.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 09/568/570, filed May 10, 2000, and titled "INVENTORY
REPLICATION BASED UPON ORDER FULFILLMENT RATES," which claims
priority under 35 U.S.C. 119(e) from U.S. Provisional Patent
Application No. 60/133,646, filed on May 11, 1999, and titled
"ELECTRONIC COMMERCE ENABLED DELIVERY SYSTEM AND METHOD." These
applications are incorporated herein by reference for all
purposes.
[0002] This application is also related to (i) U.S. patent
application Ser. No. 09/568,603, now U.S. Pat. No. 7,177,825,
titled "INTEGRATED SYSTEM FOR ORDERING, FULFILLMENT, AND DELIVERY
OF CONSUMER PRODUCTS USING A DATA NETWORK," (ii) U.S. patent
application Ser. No. 09/568,569, now U.S. Pat. No. 6,622,127,
titled "ORDER ALLOCATION TO SELECT FROM INVENTORY LOCATIONS
STOCKING FEW UNITS OF INVENTORY," and (iii) U.S. patent application
Ser. No. 09/568,571, now U.S. Pat. No. 7,139,637, titled "ORDER
ALLOCATION TO MINIMIZE CONTAINER STOPS IN A DISTRIBUTION CENTER."
Each of the above-referenced US patent applications is incorporated
herein by reference for all purposes.
BACKGROUND OF THE INVENTION
[0003] The present invention relates to distribution centers for
distributing inventory to customers. More particularly, the
invention relates to load balancing in distribution centers.
[0004] Distribution centers are buildings or regions where
inventory is stored and used to fulfill orders for customers.
Customers place orders by various modes such as by telephone, mail,
Internet browsers, and the like. The enterprise running the
distribution center attempts to fulfill as many orders as possible
in the shortest amount of time.
[0005] A distribution center's "throughput" is defined as the
volume of inventory or number of orders fulfilled in a given unit
of time. At least two parameters feature prominently in maximizing
throughput: (a) useable inventory and (b) load balancing during
order fulfillment. Usable inventory simply refers to the amount of
inventory that is immediately available for order fulfillment.
Obviously, if a distribution center has insufficient inventory to
immediately fulfill all its orders, that distribution center cannot
realize its potentially highest throughput. Load balancing refers
to consistently using all order fulfillment mechanisms available
for fulfilling orders. If any of these mechanisms sit idle,
throughput drops off rapidly.
[0006] A given distribution center may have many order fulfillment
mechanisms. In one example, the distribution center includes a
conveyor belt that transports a container to various locations,
each of which has an order fulfillment mechanism. One location may
have a bank of carousels, each containing numerous bins. Each bin
holds one or more types of inventory. The carousel moves into a
position where items of inventory can be placed in the container on
the conveyer belt. Another location may have a few aisles each
containing multiple bins. A worker moves through the aisles to pick
out requested items and place them in the container. Other types of
order fulfillment mechanisms may be employed. The term "pod" will
be used herein to describe any and all types of order fulfillment
mechanisms. Each pod has one or more types of inventory available
for "picking." Picking refers to the operation of retrieving an
item of inventory from a pod and placing it into a container. The
container holds the various items that fulfill a given order.
[0007] Given that different customers have very different needs and
preferences, different orders provide wide and rather unpredictable
variation. Optimal load balancing to meet this variation presents a
serious challenge. During a given week, for example, several
grocery orders may require milk, but only a few of these require
anchovies, a few others require spicy tofu, and still a few others
require cotton swabs. In fulfilling these various orders, any one
of these items could present a throughput bottleneck. Controlling
the position and path of a container used to fulfill an order can
partially address this problem. However, additional mitigation
might result from intelligently distributing or arranging the
inventory at specific locations within the distribution Center.
[0008] The present invention fills a need for better ways to
distribute inventory within a distribution center.
SUMMARY OF THE INVENTION
[0009] The present invention provides a load balancing technology
that segregates various inventory types (e.g., potatoes vs. milk,
vs. pretzels, vs. tissue paper, etc.). The inventory types are
grouped based upon how frequently they are ordered in a
distribution center. In a distribution center that distributes
groceries, for example, certain staples such as milk are ordered
very frequently. Other items such as cranberry sauce may be ordered
very infrequently (except shortly before Thanksgiving). Still other
items such as pretzels may be ordered with intermediate
frequency.
[0010] In this invention, inventory types that are ordered at the
slowest rate (e.g., cranberry sauce in the above example) are not
"replicated" over multiple pods in the distribution center. Rather,
they are constrained to reside at a single pod within the
distribution center. Items that are ordered somewhat more
frequently (e.g., pretzels) are replicated in multiple pods across
the distribution center. In other words, these items arc separately
provided at locations on more than one pod in the distribution
center. In a preferred embodiment, they are stored at all pods (or
at least all pods of a particular type such as carousels) within
the distribution center. This means that a container passing
through the distribution center can obtain each of the items it
needs from the second group at any particular pod in the
distribution center. Thus, these items do not create a bottleneck
in the order fulfillment process.
[0011] Inventory types in the third group, the fastest movers, may
be segregated from items in the first two groups. Preferably they
are stored in a separate type of pod that fulfills orders even
faster than the other type of pods. In a preferred embodiment,
inventory in the third group is stocked in a mechanical pod rather
than in a carousel. In a specific embodiment, items in this third,
fastest category of inventory are not replicated across multiple
pods.
[0012] One aspect of the invention pertains to a method of
distributing inventory to facilitate order throughput in a
distribution center. The method may be characterized by the
following sequence: (a) for each type of inventory to be
distributed, determining how rapidly that type of inventory is
consumed; (b) identifying a first group of inventory types that are
relatively slower moving types of inventory and distributing the
inventory types from this first group over multiple pods in the
distribution center without replicating a given type in more than
one pod; and (c) identifying a second group of inventory types that
are relatively faster moving types of inventory and replicating
inventory types from the second group at multiple pods. As
mentioned, the inventory may be further classified into third group
of inventory types that move faster than inventory types in the
second group. Preferably, inventory types from this group are
stocked in one or more high throughput pods.
[0013] Preferably, inventory types from the first group (the
slowest movers) are randomly distributed over the multiple pods. In
other words, a pod is randomly selected for a given inventory type
in the first group. On the other hand, inventory types from the
second group preferably are replicated over all pods in the
distribution center. In a specific embodiment, the second group
inventory types are distributed over all pods of a particular type
such as carousels.
[0014] Various mechanisms may be employed to determine how rapidly
inventory is consumed. For example, the distribution center may
track how frequently the various inventory items are ordered. In a
preferred embodiment, inventory items in the first group (the slow
movers) are identified as those that are consumed at a rate of less
than one bin's worth of inventory per unit time; a bin is a portion
of a pod that holds only one inventory type. In a very specific
example, inventory types that move at a rate of less than 10 bins
per week are identified as belonging to the first group of
inventory types.
[0015] Another aspect of this invention pertains to distribution
centers having inventory arranged to facilitate order throughput.
Such distribution centers may be characterized by the following
group of features: (a) a conveyor for moving containers throughout
the distribution center in a manner allowing items in the
distribution center to be placed in the containers to fill orders;
(b) a plurality of pods proximate the conveyor, each pod stocked
with specified types of inventory for filling orders; (c) a first,
slow moving, group inventory types (as described above) distributed
over multiple pods and without replication; and (d) a second,
faster moving, group of inventory types (as described above)
replicated over multiple pods. The distribution center typically
includes one or more computer controllers that direct the
containers over specified paths within the distribution center and
specify items to be placed in the containers.
[0016] The distribution center may include various types of pods
including high throughput mechanical pods that include one or more
aisles stocked with inventory and arranged to allow rapid picking.
In a preferred embodiment, inventory types from a third, very
rapidly moving, group are stocked in mechanical pods. Another
common type of pod is the carousel, which can rotate into various
positions and thereby make different items available for placement
into the containers.
[0017] Another aspect of the invention pertains to computer program
products including a machine-readable medium on which is provided
program instructions for implementing one or more of the methods or
computer user interfaces described herein. Any of the methods or
interfaces of this invention may be represented as program
instructions that can be provided on such computer readable
media.
[0018] These and other features and advantages of the present
invention will be described in more detail below with reference to
the associated figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a block diagram of a distribution center in which
inventory is placed based upon how rapidly it is consumed.
[0020] FIG. 2 is a velocity curve showing how various types of
inventory are grouped based upon their relative consumption
rates.
[0021] FIG. 3 is a flow chart depicting an order fulfillment method
that may be used in a distribution center implementing the present
invention.
[0022] FIG. 4 is a flow chart depicting a high level inventory put
away method that may be employed to implement the present
invention.
[0023] FIG. 5A is a process flow chart depicting a detailed put
away process using velocity to make decisions about
replication.
[0024] FIG. 5B is a block diagram depicting logical blocks that may
be employed to identify put away locations in a distribution center
in accordance with one embodiment of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] The following discussion presents some terms and concepts
pertinent to the operation of a distribution center. The invention
is not specifically limited to the examples described
hereafter.
[0026] Totes are storage containers used to hold products for
transportation to the consumer. There may be several different
sizes of totes. Additionally, some totes may be designed for
holding frozen and refrigerated goods. In some embodiments, the
totes are relatively sturdy and have closable lids.
[0027] Each tote may have an identifier to support automated
movement through the distribution center by conveyor. For example,
each tote can have a bar code identifier that can be scanned as it
moves past various points in the system. In this manner, a tote can
be moved from a tote induction area to a specific pod or other
location with the system tracking the location of the tote.
[0028] As indicated, a distribution center has a transport system
such as a conveyor that moves totes and trays to pods and other
locations within distribution center. "Trays" are used to transport
new inventory from a receiving station in the distribution center
to individual pods within a distribution center. Identifiers on the
trays and totes allow them to be automatically routed to specific
destinations within the distribution center. In a specific
embodiment, conveyors from Buschmann Company, Cincinnati, Ohio, are
used. In another specific embodiment, software from SeayCo
Integrators, Conyers, Ga. automates conveyor movement.
[0029] Generally, a pod is a collection of storage areas (inventory
locations or bins) within a distribution center. As mentioned, a
single distribution center may have several types of pods. Each of
the different pods and pod types may be adapted for different
temperatures, e.g., frozen goods mechanized pod. The different pods
and pod types may also be adapted for the rate of product movement,
e.g., mechanized pods for fast moving items.
[0030] Carousel pods include one or more carousels adjacent to one
or more conveyors. In one embodiment, each pod has three carousels
adjacent to two conveyors for incoming trays and totes. In some
embodiments, two additional conveyors are provided: an express
conveyor and an empty conveyor. The express conveyor is used to
transport totes directly from the carousel pod to the outbound
distribution point for totes. The empty conveyor is used to
transport empty trays back to the receiving area to receive new
incoming products.
[0031] Generally, a carousel is a rotating high capacity storage
area. Due to the rotating design of the carousels, only items
stored in a small section of the carousel can be easily accessed at
a given time. This trade-off allows the carousels to store large
numbers of items at the expense of rapid access. One suitable
carousel for use with this invention is available from Diamond
Phoenix, Lewiston, Me.
[0032] Mechanized pods, or mechanical pods, are areas designed to
hold the faster moving, and also bulkier and heavier, products for
easy access. Each mechanized pod may have inbound and outbound
conveyors. Received products may be placed directly into the
mechanical pod for storing. Because the mechanical pod items may
also be bulkier and heavier than other products, totes that include
mechanical pod items may be sent to the mechanical pod prior to the
other pods.
[0033] Manual pods are areas where "fill to order" items such as
produce, bulk foods, pharmacy prescriptions, and/or prepared meals
may be prepared and/or stored. The products in the manual pods are
typically placed in totes last. Products in manual pods are
customer specific preparations. Items are brought from fill to
order preparation areas to the manual pods for placement (pick
tasks) into totes.
[0034] A "pick task" is the retrieval of a product, or multiple
quantities of the same product, to fill an order. Thus, an order
for ten different products would be comprised of ten pick tasks.
However, if the order included five bags of Brand X potato chips,
that might be consolidated into a single pick task--depending on
the number of bags of potato chips in the pod. For example, if pod
two had only two bags of potato chips left and pod three had the
last three bags of potato chips, two pick tasks would be
required.
[0035] Carousel pick tasks may require the coordination of the
conveyors to transport the tote to the appropriate pod with the
carousels to bring the appropriate storage tray to an accessible
position. The pick task may be scheduled, or generated, prior to
the actual physical movement of the product, or products, from a
carousel location to a tote. Once the pick task is accomplished,
the conveyor may move the tote to the next destination
automatically. In some embodiments, a push button signal is
employed to allow the pick operator to signal that she/he has
placed the product, or products, into the tote. Mechanized pick
tasks can be accomplished by using carts to move totes received on
the inbound conveyor to the products. The products can then be put
into the totes for delivery. Once the necessary items are in the
totes, the tote is placed on the outbound conveyors. The process
for manual pick tasks may be similar to the mechanized pick task.
The tote that arrives on the inbound conveyor is scanned. A list of
locations with items for the tote is displayed. An operator
retrieves the indicated items from the listed locations and then
transfers the tote on the outbound conveyor.
[0036] A put-away task is the storage of a product in a pod. The
product must be stored in a temperature appropriate pod. For
example, dairy products must be stored at certain temperatures to
avoid spoilage. In addition, depending on the type of product, one
of the different types of pods will be selected.
[0037] The carousels are used to store items in trays. Once the
products have been placed in trays, they can either be sent by
conveyor for direct put away in the carousels or held on flow racks
for later put away. The scheduling of the put away can be based on
product shipments, available inventory, load, and other
options.
[0038] Once the tray is received by conveyor at the carousel pod,
audible and/or visual annunciators indicate the storage location
for the tray. The carousel movements are coordinated with the
conveyors so that the appropriate storage area of the carousel is
available when the tray is to be stored. Weight planning can be
used so that heavier trays are stored at or below waist level while
lighter trays are stored at or above waist level in the
carousel.
[0039] Each mechanical pod item has one or more fixed locations.
For example, diet soda might be stored in at location A-1. Thus,
when the put away operator received diet soda, she/he will scan it
and be told to store it at A-1.
[0040] FIG. 1 presents a highly simplified depiction of a
distribution center 101. In this figure, a container 103 known as a
"tote" is introduced into a tote path in the distribution center
and moves about on a conveyor 105. It may stop at various pods as
it moves throughout distribution center 101. At each pod, a human
being, a robot, or a specialized mechanical device "picks" items
from the pod and places them into the tote 103. At the end of the
process, tote 103 is filled with items that are used to fill an
order. A given order may include one or more totes filled with
ordered items.
[0041] In the example depicted in FIG. 1, there are two types of
pods: a mechanical pod 107 and carousels 109, 111, and 113. Various
items, each representing a distinct inventory type, are provided in
slots (e.g., bins) or other portions of the pods. Thus, each pod
may contain numerous inventory types. Often these inventory types
are referred to as SKUs (Stock Keeping Units). In a carousel, items
are provided in particular slots or bins, which are rotated into
position next to conveyor 105 to facilitate picking. In the example
depicted in FIG. 1, carousel 109 has rotated into a temporary
position with the items of SKU 02 available for picking. Likewise,
carousel 111 has items from SKU 05 available for picking and
carousel 113 has items from SKU 01 available for picking.
Typically, when tote 103 stops at a conveyor position, it remains
at that location until all items available at the proximate pod are
picked and put into the tote (assuming that those items are
necessary to fill an order associated with tote 103).
[0042] As mentioned, each different item of inventory is associated
with a respective SKU. For reference, a "product" is a grouping of
SKUs. Product information is higher level information that is
pertinent to all SKUs in the grouping. It often defines a brand. A
"category" is an even higher level classification based on how
customers would expect products to be logically grouped. For
example, the category "potato chips" may include the products
"Brand X" potato chips and "Brand Y" potato chips. Further, the
Brand X potato chip products may include a 16-ounce Brand X potato
chips item (associated with a first SKU) and a 20-ounce Brand X
potato chips item (associated with a second SKU).
[0043] While FIG. 1 shows a distribution center having only one
area that contains all pods, a typical distribution center may be
divided into many more regions. For example, a distribution center
may have three main temperature zones for products: ambient,
refrigerated, and frozen. And within these three zones, there may
be subzones for specialty items, e.g., for flowers, cigars, wines,
and chocolates. Each zone or subzone may have its own collection of
pods. Further, a distribution center may have kitchens, bakeries,
deli departments, pharmacies, and other facilities to provide
certain products. FIG. 2 presents a "velocity curve" 202 showing
order frequency (y axis) versus inventory types (x axis).
Essentially, velocity curve 202 ranks inventory types by how fast
they are used to fill orders. In the example of FIG. 2, items of
SKU 12 and SKU 11 are consumed very rapidly. These may be potatoes
and milk, for example. Moving down velocity curve 202, items in SKU
01 and SKU 05 are ordered at an intermediate rate. Near the slowest
side of curve 202, the items of SKU 02, SKU 06, SKU 03, and SKU 04
reside.
[0044] In a preferred embodiment of this invention, inventory types
are divided into two or more groups based upon where they reside on
a velocity curve. As shown in the example of FIG. 2, inventory
types at the slow end of velocity curve 202 are members of a First
Group 204. Inventory types that move at intermediate velocity
become members of a Second Group 206. Finally, inventory types that
are consumed most rapidly from the distribution center become
members of a Third Group 208.
[0045] This grouping is used to determine where individual
inventory types are stocked within a distribution center. More
specifically, methods of this invention select inventory types for
specific pods based upon where the inventory types reside on a
velocity curve.
[0046] In a preferred embodiment, items in the fastest moving group
(Group 3 of FIG. 2) are provided in specially designed, very high
speed pods such as mechanical pod 107 shown in FIG. 1. In many
embodiments, items from the fastest moving inventory types are
stored in only a single pod within a distribution center. In other
words, they are not distributed at multiple pods within the
distribution center. In the example of FIG. 1, all milk and
potatoes (high-speed items) are stored only in mechanical pod 107.
In other embodiments, such items are distributed over both a
mechanical pod and a carousel to give more allocation
flexibility.
[0047] The very slow moving items are not replicated over multiple
pods. Rather, for each item in this group, the methods of this
invention randomly select a pod. In the example of FIG. 1, items in
SKU 02, SKU 03, SKU 04 and SKU 06 fall into this category. Thus,
they are not replicated across multiple pods in distribution center
101. Preferably, such items are not stocked in the fastest moving
pods. In the examples described herein, the slow moving items would
be stocked only in carousels.
[0048] Those inventory types falling within the second group of a
velocity curve are replicated across multiple pods in a
distribution center. Thus, for example, items from SKUs 01 and 05
reside on multiple pods. In the specific example of FIG. 1, these
items reside on each of the carousels 109, 111, and 113.
Preferably, though not necessarily, such items are not stocked in
the fastest moving pods. In some instances, it may be desirable to
allow some of these items to be replicated in both carousels and
mechanical pods.
[0049] Typically, items from Groups 1 and 2 (the slow and medium
speed groups) are constrained to reside only on carousels or other
relatively slow moving pods. On the other hand, items from Group 3
(the fastest moving group) are allowed to reside in a very fast
mechanical pod. Thus, in this embodiment, Groups 1 and 2 are
distinguished from Group 3 based upon which type of pods they
reside in. Groups 1 and 2 are distinguished from one another based
upon whether they are replicated within their types of pod.
[0050] As suggested, however, the invention is not limited to these
distinctions. For example, some distribution centers may have only
a single pod type. In such cases, the important distinction will be
drawn between Groups 1 and 2, where items in Group 1 are not
replicated and items in Group 2 are replicated. Further, in
distribution centers that contain two or more pod types, some items
from Group 3 may reside on both pod types. Further, some items from
Group 2 may reside on both pod types.
[0051] One reason to replicate some inventory items and not others
is to balance the competing concerns of efficiently using available
floor space and rapidly filling orders. Those items that are
consumed relatively slowly, should not occupy floor space that
could be more productively used to store faster moving items.
Further, to fill orders rapidly, a tote should generally make as
few stops as possible on its path through the distribution
center.
[0052] Using the replication strategy of this invention, totes will
generally require fewer stops to fill a given order. Stops will
generally be determined by the slow moving items (Group 3) in a
given order. For example, assume that an order requires milk,
potatoes, an item from SKU 01, an item from SKU 04 and an item from
SKU 05. Referring to FIG. 1, tote 103 will first stop at mechanical
pod 107, where it receives milk and potatoes as necessary to fill
its order. To obtain the items from SKUs 01 and 05, the tote could
stop at any one of carousels 109, 111 and 113. However, the only
item in the order from Group 1 (SKU 04) is located only at carousel
109. Thus, tote 103 stops at carousel 109 where the remaining items
from the order can be picked. Because the distribution center
replicates relatively faster moving inventory types, it minimizes
the number of tote stops for many orders--as illustrated in this
example.
[0053] As mentioned, the process of grouping inventory types into
two or more separate groups for determining replication and pod
type relies on the use of a velocity curve. However, the line
between inventory items in two adjacent groups need not always be
sharp. Further, the location of these lines on the velocity curve
may vary from distribution center to distribution center depending
upon the types, numbers, and placement of pods within the
distribution center.
[0054] In one embodiment, the fastest moving inventory types are
provided in mechanical pods. Starting with the fastest movers and
continuing down the velocity curve, each inventory type is provided
in the mechanical pods until there is no more available space in
the mechanical pods. Continuing down the velocity curve, the next
item types are provided in slower pods and replicated across these
pods. At some point on the velocity curve, inventory items are no
longer replicated.
[0055] Drawing the line on the velocity curve between the
replicated and non-replicated items can be somewhat arbitrary. In
one embodiment, the volume of a bin within a pod is used to help
make this determination. If the quantity of items consumed in a
given time period requires less than a full bin, then that item is
deemed to be a slow mover which will not be replicated. For
example, consider an item that can fit three of itself in a single
bin. Assume further that there are ten pods over which replicated
items must be distributed. Then, one might determine that thirty
units of the item must be consumed within a week (or other unit of
time) in order to support replication. If the consumption rate of
this item is less than thirty per week, then the item is deemed a
slow mover and is not replicated. In a different example, consider
an item, which can fit four of itself within a given bin. And,
assume that there are five pods over which replicated items are
distributed. In this case, the item would have to be consumed at a
rate of at least 20 units per week (or other unit of time) in order
to be replicated. If the item did not support this level of
consumption, then it would not be replicated. This example suggests
that the order frequency or consumption rate on the velocity curve
may be measured in terms of (bins or slots of the inventory type)
consumed per unit time. Of course, other measures of consumption
rate may be employed to draw the line between replicated and
non-replicated inventory types.
[0056] As described in U.S. patent application Ser. No. 09/568,603,
now U.S. Pat. No. 7,177,825 (previously incorporated by reference),
a distribution center may include a system of conveyers, carousels,
scanners, and hand-held computing units for automating both the
order fulfillment (outbound) and inventory restocking (inbound)
processes, which are managed by a computer implemented Order
Fulfillment Subsystem of the distribution center.
[0057] One suitable outbound order fulfillment flow will now be
depicted with reference to FIG. 3. Understand that various order
fulfillment process flows may benefit from the technology of this
invention. In FIG. 3, an order fulfillment flow 301 is depicted.
Typically, this flow will be controlled and implemented by one or
more computer systems associated with a distribution center. It
begins at 303 with an order arriving for fulfillment. Such order
may arrive via mail, telephone, the Internet, etc. In a preferred
embodiment, the order is provided as a computer readable file in a
standard format.
[0058] Next, at 305, order allocation takes place. This typically
involves matching an order with particular inventory stored in a
distribution center and determining where that inventory is
located. It may also involve decrementing inventory within the
distribution center under the assumption that such inventory will
be picked to fill the order. Still further, the allocation process
may determine the number of totes needed to fulfill the order and
design the path for each tote to follow while the order is being
filled. This path will specify various pods at which the tote stops
to have particular items picked to fill the order.
[0059] Next, at 307, a tote is inducted into the system and begins
passing through the distribution center according to its
pre-specified path. As it travels through the distribution center,
it stops at various pods where a computer system provides
instructions for pickers to pick selected items for the order. In a
preferred embodiment, pickers place specified order items into the
tote, and verify the order item fulfillment by scanning each item
placed into the tote, as well as the tote's license plate ID, with
a handheld computing device (e.g., RF gun). After the picker has
confirmed placement of the specified items into the designated
tote, the tote is then reintroduced to the automated tote transport
system, where it continues to travel along its designated tote
path. Information about the picked items is fed back to a central
computer system which tracks order fulfillment and inventory. The
tote is routed through various pod locations until the order is
completed. See 309. The tote path may be dynamically and
automatically altered if problems are detected in any portion of
the DC operations.
[0060] After all items for a particular tote have been picked and
confirmed, the tote is routed to a shipping spur at 311. At this
point, the tote contains all inventory items that are required to
fulfill its component of the order. A shipping component of the
distribution center can now take over processing the order. At 313,
workers or mechanical systems unload the tote onto dollies, which
may include other totes intended for a specific delivery route. At
315, workers or mechanical systems load the dollies and totes onto
trucks destined for specified locations. The trucks deliver orders
to the customers who have placed orders. At this point, the order
fulfillment process is completed. The distribution computer system
may be notified of a shipment confirmation.
[0061] Frequently a distribution center is divided into multiple
"ambiences," which dictate special storage or handling. For
example, many grocery items must be refrigerated. Such items are
stocked in a refrigeration ambience. Wines and cigars can also be
stocked ambiences having specific temperature and humidity
controls. Other items may be deemed fragile therefore stocked or
handled separately from other items. Each of these ambiences may
have its individual items grouped by velocity and stocked according
to the requirements of this invention. In one sense, each ambience
may be viewed as a separate distribution center within a larger
distribution center having multiple ambiences.
[0062] Like the outbound procedure depicted in FIG. 3, items may be
received and restocked in the distribution center using an
automated material handling and transport system. FIG. 4 shows a
flow diagram of an inventory restocking procedure 400 in accordance
with a specific embodiment of the present invention. Typically,
this process will be controlled and implemented by one or more
computer systems associated with a distribution center. The
inventory restocking process initially begins with a purchase order
being generated for specific inventory items. At 402, an expected
receipt relating to the purchase order is received. The expected
receipt data may include, for example, the vendor name, an expected
receipt ID number, estimated arrival time of the shipment, and the
SKUs and quantities of the items ordered. Once the expected
shipment is received (404) at the distribution center, the received
merchandise is checked (406) into appropriate trays. A tray
represents a container which may be used to transport received
items of merchandise for restocking. Each tray may include a
unique, scannable license plate ID. When merchandise is checked
into a tray, both the merchandise and the tray may be scanned using
an RF gun. The trays are then automatically routed (408) to their
appropriate locations using the automated conveyer system. Once a
tray arrives at its designated location, the items from that
particular tray are stored (410) and confirmed by the picker (via
an RF gun, for example). According to a specific embodiment, for
each completed tray of items restocked, an expected receipt
confirmation is generated (412) and stored. The expected receipt
confirmation data may include, for example, the expected receipt
ID, the SKU(s) of the items restocked and their respective
quantities.
[0063] FIG. 5A depicts a process flow diagram of a detailed
procedure for calculating velocity and using it to assign putaway
locations. This process is but one of the many that can be employed
within the context of this invention. As depicted, a process 501
begins at 503 with the system querying order tables (or other data
sources) on recent orders to obtain specific information about such
orders.
[0064] After obtaining the relevant order information, the system
calculates the velocity of the various items for which order
information has been obtained. See 505. In a preferred embodiment,
the system makes this calculation for each item by summing the
number of order lines for this item over a defined period of time.
In order tables, orders are represented by product IDs, which are
distinct for each SKU, and quantities. Each order line represents a
particular SKU appearing on a customer order. For example, a
customer order may specify three apples and ten oranges. Apples
would form one order line and oranges would form a second order
line. In this embodiment, the quantity of items associated with
each order line is not factored into the velocity calculation. In
an alternative embodiment, the quantity information is used to
calculate velocity.
[0065] Preferably, the basic sampling interval chosen for
calculating velocity accounts for any periodicity in the particular
SKUs moving through the distribution center. For groceries, for
example, one week accounts for most of the periodicity. Thus, in
the case of a grocery warehouse, the number of order line
occurrences would be calculated over one week sample intervals. To
improve the accuracy of this calculation for slow moving SKUs, the
basic sample interval may be increased selectively for such SKUs.
In one implementation, the system determines whether the SKU has
reached a threshold number of order lines within the basic sample
interval. If such threshold is not met, the system then extends the
sample interval over which the velocity is calculated.
[0066] After velocity has calculated 505, the system ranks the SKUs
based upon their calculated velocities. See 507. Typically the
ranking will place the fastest movers at one end of a scale and the
slowest movers at the other end of the scale. Next, the system
categorizes the SKUs based upon their relative velocity rankings as
well as certain other attributes. See 509. Among the other
attributes that may be considered are ambience (already mentioned),
conveyability, fragility, and special handling considerations such
as security for very valuable items and regulatory consideration
for prescription drugs, for example.
[0067] Based upon velocity and one or more of these other
attributes, the system next assigns putaway areas. See 511.
Typically, a putaway area represents a collection of slots or bins
within a particular pod. In one example, a single pod includes
three separate carousels. Each such carousel is divided into
multiple areas. And, each area contains a number of slots. Each
slot is reserved for a specific SKU. In one example, an area might
represent the middle three shelves of a particular carousel.
[0068] Note that when an item's velocity indicates that it should
be replicated, the system takes account of this when assigning
putaway areas at 511. In some instances, an item whose velocity is
not sufficiently great to indicate forced replication, may be
"opportunistically" replicated. This may occur when more instances
of that item must be put away than can fit in a single slot. When
this occurs, the system opportunistically replicates that item over
multiple pods.
[0069] The system may account for numerous factors when identifying
putaway slots. In addition to the velocity and other attributes and
the possibility of opportunistic replication, the system may
consider the location of existing inventory in assigning a putaway
area. Using any or all of these criteria, the system preferably
uses some probability information and possibly random number
generation to assign putaway areas. Typically, as part of the
operation at 511, the system also assigns multiple putaway areas
that may be represented as a chain of putaway areas. The first
member of the chain is the most preferable putaway area and
subsequent members are less preferred areas.
[0070] With a proposed putaway area in hand, the system next
attempts to put the current SKU in a slot within the assigned
putaway area. See 513. In some instances, this will not be possible
because all slots in the area are taken. Thus, the system
determines, at 515, whether a suitable slot has been located. If
not, process control returns to 511 where the system next assigns a
different putaway area. In the embodiment just described, this next
putaway area will be the next successive putaway area provided in a
chain of putaway areas. Eventually, the system will find an
appropriate slot within one of the assigned putaway areas. When
this occurs, the system determines whether there are any more SKUs
to be processed at 517. If so, it assigns one or more proposed
putaway areas at 511. If not, the process is completed.
[0071] FIG. 5B presents a block diagram of various logical modules
that may be used to implement the method of FIG. 5A or a similar
method. As shown, a system 525 for providing putaway tasks includes
a warehouse management system 527, a velocity estimator 529, and a
putaway planner 533. Any one or more of these logical entities may
be implemented at hardware, software, or some combination
thereof.
[0072] In a preferred embodiment, warehouse management system 527
includes a database 529 containing logical tables providing order
information organized as order lines for example. Preferably, the
velocity estimator 529 queries warehouse management system 527 to
obtain order line information. Velocity estimator 529 then uses
such order line information to calculate velocity as indicated at
505 in FIG. 5A. The velocity estimator may then rank the individual
SKUs and place them in a velocity table 531.
[0073] Putaway planner 523 categorizes specific SKUs based upon SKU
velocity data from velocity estimator 529 and other SKU attributes
from warehouse management system 527. Based on this information,
putaway planner 533 assigns putaway areas. As mentioned in the
discussion of operation 511, the putaway planner may generate a
chain of proposed putaway areas. It provides one or more of these
putaway areas to the warehouse management system 527. The warehouse
management system then attempts to slot a particular SKU in the
area identified. If it cannot accomplish this, it notifies putaway
planner 533. Putaway planner 533 then provides a different proposed
putaway area to warehouse management system 527. When warehouse
management system 527 finds an appropriate slot within the proposed
area, it generates a putaway task containing instructions for
another module within the distribution center to put inventory at
assigned slots. In one example such other module is an automated
material handling controller. Warehouse management system 527 may
use the putaway information to update inventory information in its
database 529.
[0074] This invention is preferably implemented as software stored
or transmitted on a machine-readable medium and executed on a
processor. The invention may also be implemented on firmware
provided with a processor for executing instructions specified by
the firmware. In an alternative embodiment, the invention is
implemented on specially designed or configured processing
hardware.
[0075] Because program instructions and data may be employed to
implement the systems/methods described herein, the present
invention relates to machine-readable media that include program
instructions, velocity data, etc. for performing various operations
described herein (e.g., grouping inventory items based on their
location on a velocity curve and logically distributing those items
in put away regions of a distribution center). Examples of
machine-readable media include, but are not limited to, magnetic
media such as hard disks, floppy disks, and magnetic tape; optical
media such as CD-ROM disks; magneto-optical media; and hardware
devices that are specially configured to store and perform program
instructions, such as read-only memory devices (ROM) and random
access memory (RAM). The invention may also be embodied in a
carrier wave travelling over an appropriate medium such as
airwaves, optical lines, electric lines, etc. Examples of program
instructions include both machine code, such as produced by a
compiler, and files containing higher level code that may be
executed by the computer using an interpreter.
[0076] Although certain preferred embodiments of this invention
have been described in detail herein with reference to the
accompanying drawings, it is to be understood that the invention is
not limited to these precise embodiments, and that various changes
and modifications may be effected therein by one skilled in the art
without departing from the scope of spirit of the invention as
defined in the appended claims.
* * * * *