Note: Descriptions are shown in the official language in which they were submitted.
PERPETUAL BATCH ORDER FULFILLMENT
[0001] <<This paragraph has been left intentionally blank.>>
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to a method and system of batch order
fulfillment, and
a computer usable medium having a computer readable program code embodied
therein
adapted to be executed to implement the method of batch order fulfillment.
Description of Related Art
[0003] Batch picking is picking multiple orders at a time. In one method of
batch picking,
as described in U.S. Patent No. 5,812,986, an RF Cart allows a picker to pick
multiple orders
at a time while pushing a mobile cart through a warehouse. The cart directs
the picker where
to go and what to pick in a logical walk sequence.
[0004] Typically, with an RF Cart, multiple orders "N" are assigned to a cart,
each order at
its own unique location on the cart. The controller (processor or computer)
electronically
joins the orders together, making them one larger order, referred to in the
industry as a
"batch". The basis of the batch picking concept is to enable a single picker
to pick multiple
orders while only walking the distance of a pick line once, thereby improving
efficiency.
[0005] In conventional batch picking methodology, "N" orders are assigned to a
cart as a
batch, and then a picker walks a pick line, picking items as directed by the
cart in a walk
sequence. After the length of the pick line is completed, "N" orders are
completed. With this
methodology, the pick line has a starting point and an end point. The process
begins at the
starting point with "N" empty (unfulfilled) orders and ends at the end point,
which is
commonly coincident with the start point, with "N" orders completed. It is
then emptied and
reloaded with "N" new orders and the process is repeated.
[0006] The above process is enhanced by locating warehouse items (SKUs) based
on their
pick volume. Placing the most commonly picked items near the beginning of the
pick line
provides the potential that the "N" orders are completed prior to walking the
entire pick path,
thereby allowing the picker to take a shortcut back to the starting point.
However, the
process of locating high volume items to the front of the line is time
consuming and labor
intensive, and warehouse managers struggle with moving stock around to
maintain efficient
product placement.
1
CA 2863811 2019-04-30
CA 02863811 2014-08-05
WO 2013/116620 PCT/US2013/024308
SUMMARY OF THE INVENTION
[0007] A method of batch order fulfillment of the present invention includes:
assigning a
plurality of orders to a picker, each order comprising multiple units to be
picked, wherein the
picker picks the units in a logical travel sequence that generally minimizes a
travel time of the
picker; and assigning a new order comprising multiple units to be picked to
the picker after
one of the previously assigned orders is completed, wherein the picker picks
the units of the
new order and unpicked units of the previously assigned orders in logical
travel sequences
that generally minimizes a travel time of the picker.
[0008] The step of assigning a new order may be repeated.
[0009] The method may further include assigning one or more single unit orders
to the
picker.
[0010] The picker may be a mobile picking cart that has a designated location
for each
order. The completed order may be removed from its designated location and
replaced by the
new order. The mobile picking car may also have a designated location for one
or more
single unit orders.
[0011] The new order may be chosen from the plurality of available orders to
be picked
based on an increase in the picker's travel time resulting from assigning the
new order to the
picker.
[0012] A system of batch order fulfillment of the present invention includes:
a guidance
system that directs a picker to items to be picked in a logical travel
sequence that generally
minimizes a travel time of the picker, wherein the items to be picked are from
a plurality of
orders assigned to a picker, each order comprising multiple items to be
picked; and an
assigning system that assigns a new order comprising multiple items to be
picked to the
picker after one of the previously assigned orders is completed.
[0013] The assigning system may also assign one or more single unit orders to
the picker.
[0014] The system may also include a mobile picking cart that has a designated
location
for each order. The mobile picking cart may have a designated location for one
or more
single unit orders.
[0015] The assigning system may choose a new order from the plurality of
available orders
to be picked based on an increase in the picker's travel time resulting from
assigning the new
order to the picker.
[0016] A computer usable medium of the present invention has a computer
readable
program code embodied therein, said computer readable program code adapted to
be
executed to implement a method of batch order fulfillment, the method
comprising: assigning
2
CA 02863811 2014-08-05
WO 2013/116620 PCT/US2013/024308
a plurality of orders to a picker, each order comprising multiple units to be
picked, wherein
the picker picks the units in a logical travel sequence that generally
minimizes a travel time of
the picker; and assigning a new order comprising multiple units to be picked
to the picker
after one of the previously assigned orders is completed, wherein the picker
picks the units of
the new order and unpicked units of the previously assigned orders in logical
travel sequences
that generally minimizes a travel time of the picker.
[0017] The method may include repeating the step of assigning a new order.
[0018] The method may include assigning one or more single unit orders to the
picker.
[0019] The method may include choosing the new order from the plurality of
available
orders to be picked based on an increase in the picker's travel time resulting
from assigning
the new order to the picker.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIGS. 1A and 1B illustrate a method of batch order fulfillment
representative of the
related art.
[0021] FIGS. 2A-2E illustrate a method of batch order fulfillment according to
an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0022] FIGS. 1A and 1B illustrate a method of batch order fulfillment
representative of the
related art. In FIG. 1A, a picker 10 is assigned first, second and third
orders, each order
including multiple units to be picked. From the starting point, the picker
picks the units to be
picked by travelling along the pick path to the end point of the pick path,
thereby completing
the first, second and third orders. The process of FIG. 1A is then repeated in
FIG. 1B with
the picker being assigned three new orders, i.e., fourth, fifth and sixth
orders. From the
starting point, the picker picks the units to be picked by travelling along
the pick path to the
end point of the pick path, thereby completing the fourth, fifth and sixth
orders. At the end of
two complete cycles of picking, the picker is able to complete six orders
after walking two
times around the pick path.
[0023] The inefficiency of this methodology is evident by the fact that orders
are
completed at varying points along the pick path, and, as orders arc completed,
the picker
becomes progressively less efficient. If a picker starts with "N" orders and
progresses along
a route eventually completing one of the orders, the batch now becomes a batch
of only N-1
orders. This degradation of picker efficiency continues until the batch
becomes only 1
remaining order with remaining units to be picked. Thus, at the end of one
walk through the
pick path, the picker only picked "N" orders.
3
CA 02863811 2014-08-05
WO 2013/116620 PCT/US2013/024308
[0024] FIGS. 2A-E illustrate a method of batch order fulfillment according to
an
embodiment of the present invention. In FIG. 2A, a picker 20 is assigned
first, second and
third orders, each order including multiple units to be picked. From the
starting point, the
picker picks the units to be picked by travelling along the pick path until
one of the orders is
completed. In this case, the third order is completed when an item is picked
from Bin 53. At
this time, the picker 20 is assigned a new order, i.e., the fourth order, and
continues travelling
along the picking path while picking the first, second and fourth orders as
shown in FIG. 2B
until one of the orders is completed. In this case, the first order is
completed when an item is
picked from Bin 63. At this time, the picker 20 is assigned another new order,
i.e., the fifth
order, and continues travelling along the picking path while picking the
second, fourth and
fifth orders as shown in FIG. 2C until one of the orders is completed. In this
case, the second
order is completed when an item is picked from Bin 62. At this time, the
picker 20 is
assigned another new order, i.e., the sixth order, and continues travelling
along the picking
path while picking the fourth, fifth and sixth orders as shown in FIG. 2D
until one of the
orders is completed. In this case, the fourth order is completed when an item
is picked from
Bin 12. At this time, the picker 20 is assigned another new order, i.e., the
seventh order, and
continues travelling along the picking path while picking the fifth, sixth and
seventh orders as
shown in FIG. 2E. It is already evident that at the end of two complete
cycles, the picker is
able to complete at least seven orders after walking two times around the pick
path.
[0025] The improved efficiency of the methodology of FIGS. 2A-2E is evident by
the fact
that although orders are completed at varying points along the pick path, new
orders are
assigned, and the picker maintains efficiency. With this "perpetual batch"
methodology, the
same picker can complete more orders while walking the same distance.
[0026] It will be understood that the above described method is one exemplary
embodiment and that the method of batch order fulfillment may include
variations from the
above description as well as additional features, some of which are described
below.
[0027] The example of FIGS. 2A-2E shows the first, second and third orders to
be added to
the cart, such that the third order is completed before the first and second
orders are
completed. However, according to a preferred embodiment of the present
invention, the first
order would be completed before the second order is completed, which is
completed before
the third order is completed.
[0028] To understand why the orders would be completed in the order of
assignment for
the preferred embodiment, it is helpful to understand a certain philosophy. In
particular, a
pick line, which usually includes multiple aisles (as is adequately shown in
the Figures), can
4
CA 02863811 2014-08-05
WO 2013/116620 PCT/US2013/024308
be exploded into a virtual "circle". The pick line represents a pick path that
ends where it
begins, and thus the pick line can be exploded into a theoretical "circle".
Each pick location
in the pick line can then be represented in degrees or radians on a circle of
circumference
"C", where "C" represents the distance required to travel the entire pick
path. Each location
represents a specific angle on this circle. The distance between pick
locations can be
represented by the difference between the current location angle on the
"circle" and the
"angle" of the pick location(s). At the beginning, when no orders are assigned
to a batch, the
system reviews every order in a queue of pending orders, and determines a
distance factor
based on the current location of the batch cart. This distance factor
represents the distance
along the pick path required to complete the order from the current location
on the pick path.
The order with the lowest distance factor is then added to the batch. In the
case of an empty
cart, the "N" orders with the smallest distance factor are added to the batch,
based on their
rankings shortest to longest. Thus, the first order would be the order with
the smallest
distance to travel from the current location and thus would be the first order
to be completed.
Thus the third order would not be completed before first order. It should also
be noted that
the direction of movement around the pick "circle" is always the same
direction. No orders
are selected that require the picker to move backward on the pick path.
[0029] Once the cart is in normal operation, and new orders are being assigned
to the
batch, it is possible for newly added order(s) to completed earlier than older
orders already
assigned. This case exists when the pending pool of orders is dynamically
changing based on
orders being received from customer throughout the day. Thus the pending pool
is dynamic,
not a fixed order queue.
[0030] In one embodiment, the picker may be a mobile picking cart that has a
designated
location for each order. For instance, the cart may have only "N" designated
locations for
holding orders. According to the method of FIGS. 1A-1B, the cart is used
inefficiently as
orders are completed, and the cart become less efficient. If the cart starts
with "N" assigned
orders and progresses along a route eventually completing one of the orders,
the batch
assigned to the cart now becomes a batch of only N-1 orders. This degradation
of cart
efficiency continues until the batch becomes only one remaining order with
units to be
picked. Thus, at the end of one walk through the pick path, the cart only
picked "N" orders.
However, with the "perpetual batch" methodology, the same cart with "N"
locations can
complete many more than "N" orders while travelling the same distance.
[0031] Also, the mobile picking cart may be a RF cart. The RF cart is a
paperless order
fulfillment system that utilizes hardware mounted to a mobile cart. The RF
carts provide a
CA 02863811 2014-08-05
WO 2013/116620
PCT/US2013/024308
method of picking multiple orders at a time on a single pass through the
warehouse, making
order pickers more accurate and productive. The RF carts are computer
controlled and
communicate with a centralized computer system via a RF network, providing
real-time
response and reporting. The system directs pickers to warehouse pick locations
in the most
efficient route, minimizing walk distance while fulfilling multiple orders at
once. However,
the RF Cart is merely one exemplary mobile picking cart used in the method of
batch
picking. This method can apply to any operation that batch picks orders,
regardless if the RF
cart is being utilized. This could be utilized with RF Terminals, Voice
recognition, or pick
sleds (basically RF Carts without wheels that travel on a conveyor adjacent to
pick locations).
[0032] In one aspect, there is a system of batch order fulfillment in order to
achieve the
above-described method. This system may include a guidance system and an
assigning
system, which may be integrated together or separate. The guidance system
directs the picker
to items to be picked in a logical travel sequence that generally minimizes a
travel time of the
picker. The assigning system assigns a new order comprising multiple items to
be picked to
the picker after one of the previously assigned orders is completed. The
guidance system
may include a system for directing the picker, for example, audibly or
visually, or may
include a system for controlling the movement of a vehicle or cart associated
with the picker.
The assigning system may include a computer system or other controller that
assigned new
orders to the picker from a plurality of available orders to be picked. The
computer system or
controller may be separated from but in communication with the picker, or the
computer
system may travelling along with the picker as part of the cart or vehicle.
100331 In another aspect, there may be a computer usable medium having a
computer
readable program code embodied therein that is adapted to be executed to
implement the
method of batch order fulfillment. With this aspect, software controlling the
picking process
creates a batch. Although the orders to be assigned may be chosen randomly or
by using
commonality algorithms, it is preferred that the orders to be assigned are
chosen based on an
increase in the picker's travel time resulting from assigning the new order to
the picker, or
may be chosen based on the minimum travel distance or time from the current
point on the
pick path. In this case, the software may assign orders to the picker or cart
based on finding
orders that can be completed with the minimum amount of travel from the
current cart
position or from the last picked item position.
[0034] Additionally, in another aspect, there is no dedicated start point or
endpoint. In this
case, a plurality of carts or pickers may be scattered randomly throughout a
pick line. This
6
CA 02863811 2014-08-05
WO 2013/116620 PCT/US2013/024308
distribution of the carts or pickers avoids collision and passing requirements
necessitated
when multiple pickers are traversing a pick line simultaneously.
[0035] In the case of multiple carts, at the beginning of the picking process,
for each cart in
the system, the software selects "N" orders corresponding to the number of
order locations on
the cart, based on the "N" orders that can be completed in the shortest travel
distance or
shortest travel time. The picker completes picks until he/she reaches a point
where an order
completes. The order may be removed and placed in a completed order queue,
either on the
cart, or on a conveyor that transports the order to a shipping area. The
software may then
determine, from all available orders, which order can be assigned to the freed
location on the
cart that can be completed in the least travel distance or least travel time.
That order is
assigned to the freed location and picking continues. The process of replacing
completed
orders with new orders that can be picked with least travel continues
indefinitely, until all
orders are completed.
[0036] Also, it is possible that an order can be chosen for assignment other
than shortest
travel distance or shortest travel time. However, it is generally understood
by the inventor
that the pick time will generally be minimized and that the number of orders
completed per
"revolution" of the pick circle exists when the order added to the batch is
completed with the
shorted distance. Other batch optimization techniques exist that select orders
based on
commonality, where rather than selecting orders based on distance to complete,
orders are
selected based on having common items (SKUs). According to simulation
analysis,
minimizing the distance to complete an order provides the best efficiency, but
the present
invention is not be limited to that selection method.
[0037] A benefit of the above described embodiments is that "N" location carts
are always
picking "N" orders at a time. This provides much greater efficiency than the
conventional
method where the carts progressively get less efficient as the batch size
decreases as orders
are completed.
[0038] Another benefit of the above-described embodiments is that the
methodology
thrives on randomness of item location in a warehouse. Having high volume
items randomly
scattered throughout a pick line actually makes this system more efficient, as
there is no start
and endpoint. This relieves the warehouse manager of many SKU management tasks
along
with the associated labor and downtime associated with moving items around.
[0039] Another feature is the potential to handle "Single Unit Orders". In
many direct to
consumer order fulfillment operations, the order quantity is often a single
unit. The perpetual
batch methodology can implement the ability to pick single unit orders. For
instance, a
7
single, preferably larger, order location on the batch cart can be dedicated
to receive single
unit orders. Any order in the system that is a single unit can be dynamically
assigned to each
individual batch if that item resides between the current location on the pick
path and the next
batch pick location. Thus, any single unit order is not available for
inclusion in batches.
These orders are added to any batch cart that happens to be passing the
warehouse location.
When the single unit order location on the cart fills, it is removed and sent
to a secondary
processing station where each item is removed and assigned to an order
dynamically. As
each of these orders is completed as a single unit, no order integrity is
required until it arrives
at the secondary processing (shipping) station.
[0040] To provide a further description of single unit order shipping,
basically, a bin, box,
or other storage medium containing batch picked single unit orders is removed
from a cart
and delivered to a shipping station. This station is typically equipped with a
computer,
monitor (often touch screen), bar code scanner, label printer, and a scale.
Since every item in
the tote represents a unique and individual order, each item is a shipment in
itself. The
operator at the shipping station typically removes an item from the container,
scans an
identifying bar code on the product, places the item into a shipping container
or envelope,
and places the item on a scale. The software finds a pending (queued) order
that required
only that item (SKU) from its database, calculates shipping based on the
delivery address and
weight, and prints both a shipping label and a packing slip for that order.
This process
continues for each item in the container.
[0041] It will be understood by those skilled in the art that the word
"walking" or "walk" is
used because many picking operations include carts that are pushed through a
pick line
manually, and hence, the picker is walking. The present invention is not
limited to
circumstances where carts are used or where walking is required. The present
invention
applies to any situation that utilizes any form of batch picking, whether
automated or manual.
Also, the present invention is not limited to the use of batch pick carts,
which were chosen for
describing the process as it is a common implementation of this technology.
For example, a
conveyor, automatic guided vehicle, conveyed sled, or other method of
transportation other
than walking could be utilized.
[0042] Although the invention has been described in detail for the purpose of
illustration
based on what is currently considered to be the most practical and preferred
embodiments, it
is to be understood that such detail is solely for that purpose and that the
invention is not
limited to the disclosed embodiments, but, on the contrary, is intended to
cover modifications
and equivalent arrangements. For
8
CA 2863811 2019-04-30
CA 02863811 2014-08-05
WO 2013/116620
PCT/US2013/024308
example, it is to be understood that the present invention contemplates that,
to the extent
possible, one or more features of any embodiment can be combined with one or
more features
of any other embodiment.
9
