Time-based warehouse movement maps

• US 20050278062A1
• Filed: 06/15/2004
• Published: 12/15/2005
• Est. Priority Date: 06/15/2004
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Shakes, Jonathan J., Hanssens, Nicholas M., Janert, Philipp K., Hodge, Dennis R.
• Granted Patent: US 7,243,001 B2
• Time in Patent Office: Days
• US Class Current: 700/214
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management
• CPC Class Codes: G06Q 30/00 Commerce

Abstract

A computer software facility for generating and implementing a temporal map depicting a relationship between locations in a warehouse or distribution center is described. The facility tracks the movement in the warehouse, including the time it takes for mobile elements to move between a pair of identifiable locations. Based on the tracking, the facility produces movement time records for multiple location pairs in the warehouse. The facility then generates a map of the warehouse. Where information for specific pairs of identifiable locations is not available, the facility may derive movement time information based on actual movement times for related location pairs. The generated map can be used as part of a computer application for tasks such as scheduling the picking of items, evaluating employee performance, organizing the storage of items in the warehouse, and other uses.

Claims

1. In a computer system, a method for generating a map establishing relative locations in a distribution warehouse configured for storing items for customer orders, the method comprising:

defining locations in the distribution warehouse, wherein the defining includes assigning an identity to each location in the distribution warehouse, so that each location in the distribution warehouse is uniquely identifiable;

tracking movement times between the locations in the distribution warehouse such that, for each pair of the locations, the tracking comprises;

assigning a picker to pick a first item at a first location and recording the picker'"'"'s presence at the first location;

assigning the picker to pick a second item at a second location and recording the picker'"'"'s presence at the second location;

tracking the time it takes for the picker to move between the first location and the second location, wherein the tracking includes analyzing information associated with the picker'"'"'s presence at the first location and analyzing information associated with the picker'"'"'s presence at the second location; and

creating a record for the time it takes for the picker to move between the first location and the second location, wherein the record includes an identifier for the first location, an identifier for the second location, and an actual movement time;

generating a map of the distribution warehouse, wherein the map comprises a collection of temporal relationships between a substantial portion of the uniquely identifiable locations in the distribution warehouse, and wherein the temporal relationships are based on either actual movement times obtained from the tracking or, where an actual movement time for a pair of locations is not available, on estimated movement times derived from the actual movement times; and

using the generated map to schedule future picks to occur at the distribution warehouse.

2. The method of claim 1 further comprising:

once the map of the distribution warehouse is generated, continuing to track movement times for pairs of the uniquely identifiable locations in the distribution warehouse on an ongoing basis; and

based on the continued tracking, updating the generated map of the distribution warehouse to reflect changes in movement times or changes in locations.

3. The method of claim 1 further comprising evaluating picker performance using the generated map, wherein the evaluating includes determining an expected movement time for traveling between two locations in the distribution warehouse and comparing a picker'"'"'s actual movement time between the two locations with the expected movement time.

4. The method of claim 1 further comprising generating a list of picks to be completed by a picker based on the generated map, wherein the list of picks includes a time frame for completing the picks on the list of picks and an order for completing the picks on the list of picks.

5. The method of claim 1 further comprising selecting a subset of picks from a larger pool of picks based on the generated map, wherein the subset of picks is selected to minimize the movement time when making those picks included in the subset.

6. In a computer system, a method of creating a movement time map depicting a relationship between locations in a warehouse configured for fulfilling item orders, the method comprising:

tracking the movement of workers in the warehouse so as to determine a time it takes for a worker to move between a pair of identifiable locations, each of the identifiable locations storing items for fulfilling customer orders;

based on the tracking, producing movement time records for one or more location pairs in the warehouse, wherein each one of the movement time records includes an indication of the location pair and a movement time between the location pair; and

based, at least in part, on the movement time records, generating a map of the warehouse, wherein the map provides expected movement times between the one or more location pairs.

7. The method of claim 6 wherein the map is configured for use with a computer software application, and wherein the computer software application returns an expected movement time output when given two locations as input.

8. The method of claim 6 wherein the map is configured for use with a computer software application, and wherein the computer software application is used to estimate the time it takes to pick a sequence of items from specified locations in the warehouse.

9. The method of claim 6 wherein the map is configured for use with a computer software application, and wherein the computer software application is used to schedule the picking of items in the warehouse.

10. The method of claim 6 wherein the map is configured for use with a computer software application, and wherein the computer software application is used to create or update predetermined picking paths in the warehouse.

11. The method of claim 6 wherein the map is configured for use with a computer software application, and wherein the computer software application is used to organize the storage of items in the warehouse.

12. The method of claim 6 wherein the map is configured for use with a computer software application, and wherein the computer software application is used to create or update alternative picking paths in the warehouse.

13. The method of claim 6 wherein the map is configured for use with a computer software application, and wherein the computer software application is used to define locations in the warehouse.

14. The method of claim 6 wherein the map is configured for use with a computer software application, and wherein the computer software application is used to simulate warehouse operations.

15. The method of claim 6 wherein the map is configured for use with a computer software application, and wherein the computer software application is used to facilitate replenishment or stocking of items in the warehouse.

16. The method of claim 6 wherein the map is configured for use with a computer software application, and wherein the computer software application is used to assist in financial audits.

17. The method of claim 6 wherein the locations are locations on a conveyer system for moving items within the warehouse, wherein the map is configured for use with a computer software application, and wherein the computer software application is used to schedule conveying operations.

18. A computer-readable medium whose contents cause a computing system to generate a map of one or more item storage warehouses, by performing a method comprising:

receiving data collected while traveling between locations in the one or more item storage warehouses, wherein the traveling is performed by one or more mobile elements;

for each of the one or more mobile elements, generating a record of movement times between locations to which the mobile elements traveled;

based on the generated records of movement times for each of the one or more mobile elements, determining a collection of location pairs for which movement time information is available;

for each of the location pairs in the collection, determining a set of observed movement times corresponding to movement between the locations of the location pair; and

generating a map of the one or more item storage warehouses, wherein the generating includes determining an estimated movement time for each of the location pairs in the collection of location pairs; and

wherein the estimated movement time is based on the set of observed movement times corresponding to the location pairs.

19. The method of claim 18 wherein the generating of the map includes determining an estimated movement time for location pairs for which movement time is not available.

20. The method of claim 18, further comprising:

after changes in the one or more item storage warehouses occur, gathering additional movement time data corresponding to the collection of location pairs; and

updating the generated map to reflect the changes.

21. The method of claim 18 wherein the one or more mobile elements are workers moving items within or between the one or more item storage warehouses, and wherein the workers travel within the one or more item storage warehouses on foot.

22. The method of claim 18 wherein the one or more mobile elements are vehicles moving items between the one or more item storage warehouses.

23. The method of claim 18 wherein the one or more mobile elements is an item or items on a conveyer belt.

24. The method of claim 18 wherein the one or more mobile elements are totes on a conveyer belt, and wherein the totes contain items being moved within the one or more item storage warehouses.

25. The method of claim 18 wherein the one or more mobile elements are workers moving items within in the one or more item warehouses, and wherein the workers travel within the one or more warehouses using vehicles.

26. A computer system for generating movement time maps of a distribution warehouse, the system comprising:

means for assigning an identity to each location in the distribution warehouse so that each location in the distribution warehouse is uniquely identifiable;

means for tracking the time it takes to travel between the uniquely identifiable locations in the warehouse, wherein the tracking includes generating records of location events; and

means for generating a map of the distribution warehouse, wherein the map comprises a collection of temporal relationships between a substantial portion of the uniquely identifiable locations in the distribution warehouse, and wherein the temporal relationships are based on actual movement times obtained from the generated records of location events and estimated movement times derived from the actual movement times.

27. The method of claim 26 wherein the estimated movement times are derived based on movement times associated with a single intermediary location.

28. The method of claim 26 wherein the estimated movement times are derived based on movement times associated with two intermediary locations.

29. The method of claim 26 wherein the estimated movement times are derived based on movement times associated with more than two intermediary locations.

30. The method of claim 26 wherein the estimated movement times are derived based on averaging movement times for location pairs adjacent to a location pair for which actual movement time data is not available.

31. The method of claim 26 wherein the estimated movement times are derived by replacing available sets of actual movement time data with an analytic function that computes arbitrary points.

32. The method of claim 26 wherein the location events include scanning a bar code on an item that is being retrieved from one of the uniquely identifiable locations in the warehouse.

33. The method of claim 26 wherein the location events include scanning a bar code associated with one of the uniquely identifiable locations in the warehouse.

34. The method of claim 26 wherein the location events include RFID events that occur automatically when the uniquely identifiable locations are visited.

35. The method of claim 26 wherein the location events include triggering a photoeye sensor at a known location.

36. The method of claim 26 wherein the location events are captured on a digital video camera, and wherein the location events may be analyzed by a computer to determine the location of a mobile element at a given time.

37. A method for generating and updating a warehouse map based on movement times between identifiable locations in the warehouse, the method comprising:

generating a map of the warehouse based on empirical movement time data collected during operation of the warehouse, wherein the generated map includes movement times between uniquely identifiable locations in the warehouse;

after the map of the distribution warehouse is generated, continuing to collect empirical movement time data during operation of the warehouse; and

based on the continued collection of empirical movement time data, updating the generated map of the warehouse to reflect changes in movement times or changes in locations.

38. The method of claim 37 wherein the generated map further includes estimated movement times, and wherein the estimated movement times are derived based on the empirical movement time data collected during operation of the warehouse.

39. The method of claim 37 wherein the generated map further includes seeded movement times, wherein the seeded movement times result from movement time data collected for the purpose of generating the warehouse map.

40. A method for scheduling the collection of items in a warehouse so that the collected items can be used to complete orders to be shipped to customers, the method comprising:

generating a map of the warehouse based on empirical movement time data collected during operation of the warehouse and movement time data derived from the empirical data, wherein the generated map includes movement times between uniquely identifiable locations in the warehouse;

based on the generated map, determining a schedule for collecting items in the warehouse in preparation for shipping, wherein the determining of the schedule includes assigning a picker to collect items, assigning an order for items to be collected by each of the assigned pickers, and assigning a target time for completing the collecting of each of the items; and

providing the determined schedule to the assigned pickers.

41. The method of claim 40 wherein the determined schedule is provided on mobile devices carried by each of the assigned pickers.

42. The method of claim 41 wherein the target time is an estimate of a best movement time that is determined by assessing a top percentile of movement times from the empirical movement time data.

43. The method of claim 41 wherein the target time is an estimate of an average movement time that is determined by assessing a middle percentile of movement times from the empirical movement time data.

44. The method of claim 41 wherein the target time is determined using a most frequently observed value between a pair of the uniquely identifiable locations in the warehouse.

45. A method for mapping an item storage and distribution facility using movement time data collected between specified locations in the item storage and distribution facility, the method comprising:

tracking the movement of item pickers between a first location and one or more secondary locations in the item storage and distribution facility, wherein the tracking includes generating a first set of movement time records including indications of the time it takes to move between the first location and each of the secondary locations, and wherein the movement of the item pickers between the first location and the one or more secondary locations is associated with collecting items for fulfilling customer orders;

tracking the movement of item pickers between a third location and each of the one or more secondary locations, wherein the tracking includes generating a second set of movement time records including indications of the time it takes to move between the third location and each of the secondary locations, and wherein the movement of the item pickers between the third location and each of the one or more secondary locations is associated with collecting items for fulfilling customer orders;

generating a map of the item storage and distribution facility based, at least in part, on the first and second sets of movement time records; and

where movement time records between the first location and the third location are not available, deriving an estimate of the movement time between the first location and the third location based on at least one movement time record within the first set of movement time records and at least one movement time record from the second set of movement time records.

46. The method of claim 45 wherein the deriving of an estimate of the movement time between the first location and the third location includes multiple extrapolation steps.

47. One or more computer memories collectively containing a data structure for use in generating a map of a warehouse, wherein the map depicts points of interest in the warehouse and their relative locations in terms of movement times between the points of interest, the data structure comprising:

an indication of a first point of interest in the warehouse;

an indication of a second point of interest in the warehouse; and

an indication of a movement time between the first point of interest and the second point of interest, wherein the movement time corresponds to the time it takes a mobile element to travel between the first point of interest and the second point of interest for the purpose of transporting one or more items to or from the first and second points of interest.

48. The data structure of claim 47 further comprising an indication of the frequency of movement between the first point of interest and the second point of interest.

49. The data structure of claim 47 wherein at least one of the first and second points of interest is a location where items are stored in the warehouse.

50. The data structure of claim 47 wherein at least one of the first and second points of interest is a point on a conveyer belt in the warehouse.