System and method for inventory management using mobile drive units

• US 8,831,984 B2
• Filed: 10/19/2011
• Issued: 09/09/2014
• Est. Priority Date: 10/19/2011
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Hoffman, Andrew E., Mountz, Michael C., Barbehenn, Michael T., Allard, James R., Kimmel, Matthew E., Santini, Fabrizio, Decker, Michael H., D'Andrea, Raffaello, Wurman, Peter R.
• Primary Examiner(s): Shaawat, Mussa A
• Application Number:
  US13/276,990
• Publication Number:
  US 20130103552A1
• Time in Patent Office: 1,056 Days
• Field of Search: None
• US Class Current: 705/28
• CPC Class Codes: G05D 1/0027 involving a plurality of vehicles, e.g. fleet or convoy travelling fleet control of land vehicles from a control room G05D1/0297; traffic control systems for road vehicles G08G1/00; for marine craft G08G3/00; for aircraft G08G5/00
• CPC Class Codes: G06Q 10/00 Administration; Management
• CPC Class Codes: G08G 1/096708 where the received information might be used to generate an automatic action on the vehicle control

Abstract

A method for inventory management includes deploying a first mobile drive unit having first dimensions and deploying a second mobile drive unit having second dimensions, the first and second dimensions being different. The first and second mobile drive units are operable to transport inventory items to a plurality of inventory stations in the same workspace.

Claims

1. A method for inventory management, comprising:

deploying a first mobile drive unit having first dimensions in a workspace;

deploying a second mobile drive unit having second dimensions in the workspace, wherein the first and second dimensions are different;

deploying a management module configured to maintain a three-dimensional reservation space in which the first mobile drive unit is operable to reserve a first three-dimensional reservation volume corresponding to the first dimensions and the second mobile drive unit is operable to reserve a second three-dimensional reservation volume corresponding to the second dimensions; and

wherein the first and second mobile drive units are operable to transport inventory items to a plurality of inventory stations in the same workspace.

2. The method of claim 1, further comprising

determining a first path for the first mobile drive unit;

determining a second path for the second mobile drive unit; and

reserving a first segment of the first path, the first segment comprising a first space associated with the first dimensions of the first mobile drive unit.

3. The method of claim 2, wherein the first space comprises one of a volume, a cell, and a footprint.

4. The method of claim 2, further comprising:

receiving a request to reserve a second segment of a second path;

determining whether the requested second segment intersects with a reserved space; and

determining that the requested second segment does not intersect, with the reserved space.

5. The method of claim 2, wherein reserving a first segment further comprises:

determining that the first mobile drive unit is coupled to an inventory holder;

modifying the first space based on the dimensions of the inventory holder; and

reserving a modified first segment comprising the modified first space.

6. The method of claim 2, further comprising:

applying a reservation policy, wherein reserving the first segment is based on determining that the reservation does not conflict with the reservation policy.

7. The method of claim 6, wherein the reservation policy is based on at least one of an inventory holder location, a predetermined number of maximum drives, a predetermined maximum weight, a predetermined maximum speed, and an inventory type.

8. The method of claim 2, wherein reserving a first segment further comprises:

receiving a request to reserve the first segment of the first path, the first segment representing a physical location of an inventory holder;

determining that the first segment does not intersect with the inventory holder; and

after reserving the first segment, moving the first mobile drive unit under the inventory holder.

9. The method of claim 2, wherein reserving a first segment further comprises:

receiving a request to reserve the first segment of the first path;

determining that the requested first segment comprises a partially unreserved portion; and

reserving the partially unreserved portion.

10. The method of claim 1, further comprising:

determining a capability of one of the plurality of inventory stations; and

assigning an order associated with the first and second mobile drive units to the inventory station based on the capability.

11. The method of claim 2, wherein reserving a first segment further comprises:

receiving a request to reserve the first segment of the first path;

determining that the requested first segment comprises a partially reserved portion and a partially unreserved portion;

partially granting the request of the partially unreserved portion;

further determining that an additional portion of the partially reserved portion has become unreserved; and

partially granting the request of the additional portion.

12. The method of claim 11, further comprising:

determining that the additional portion conflicts with a reservation policy; and

reducing the additional portion based on the reservation policy.

13. The method of claim 1, wherein the first and second mobile drive units are each operable to transport inventory items to one of the plurality of inventory stations in the same workspace.

14. A system for inventory management comprising:

a first mobile drive unit having first dimensions;

a second mobile drive unit having second dimensions, wherein the first and second dimensions are different;

a management module configured to maintain a three-dimensional reservation space in which the first mobile drive unit is operable to reserve a first three-dimensional reservation volume corresponding to the first dimensions and the second mobile drive unit is operable to reserve a second three-dimensional reservation volume corresponding to the second dimensions; and

a plurality of inventory holders, the first and second mobile drive units each operable to transport at least one of the inventory holders.

15. The system of claim 14, further comprising a management module operable to:

determine a first path for the first mobile drive unit;

determine a second path for the second mobile drive unit; and

reserve a first segment of the first path, the first segment comprising a first space associated with the first dimensions of the first mobile drive unit.

16. The system of claim 15, wherein the first space comprises one of a volume, a cell, and a footprint.

17. The system of claim 15, the management module further operable to:

receive a request to reserve a second segment of a second path;

determine whether the requested second segment intersects with a reserved space; and

determine that the requested second segment does not intersect with the reserved space.

18. The system of claim 15, the management module further operable to:

determine that the first mobile drive unit is coupled to an inventory holder;

modify the first space based on the dimensions of the inventory holder; and

reserve a modified first segment comprising the modified first space.

19. The system of claim 15, the management module further operable to:

apply a reservation policy, wherein reserving the first segment is based on determining that the reservation does not conflict with the reservation policy.

20. The system of claim 19, Wherein the reservation policy is based on at least one of an inventory holder location, a predetermined number of maximum drives, a predetermined maximum weight, a predetermined maximum speed, and an inventory type.

21. The system of claim 15, the management module further operable to:

receive a request to reserve the first segment of the first path, the first segment representing a physical location of an inventory holder;

determine that the first segment does not intersect with the inventory holder; and

wherein after reserving the first segment, the first mobile drive unit moves under the inventory holder.

22. The system of claim 15, the management module further operable to:

receive a request to reserve the first segment of the first path;

determine that the requested first segment comprises a partially unreserved portion; and

reserve the partially unreserved portion.

23. The system of claim 14, further comprising a management module operable to:

determine a capability of one of a plurality of inventory stations; and

assign an order associated with the first and second mobile drive units to the inventory station based on the capability.

24. The system of claim 15, the management module further operable to:

receive a request to reserve the first segment of the first path;

determine that the requested first segment comprises a partially reserved portion and a partially unreserved portion;

partially grant the request of the partially unreserved portion;

further determine that an additional portion of the partially reserved portion has become unreserved; and

partially grant the request of the additional portion.

25. The system of claim 24, the management module further operable to:

determine that the additional portion conflicts with as reservation policy; and

reduce the additional portion based on the reservation policy.

26. The system of claim 14, further comprising a plurality of inventory stations, wherein the first and second mobile drive units are each operable to transport a least one of the plurality of inventory holders to a least one of the plurality of inventory stations.

27. The system of claim 26, wherein the plurality of inventory stations comprise:

a plurality of first inventory stations operable to interact with inventory items from the first mobile drive units;

a plurality of second inventory stations operable to interact with inventory items from the second mobile drive units; and

a plurality of third inventory stations operable to interact with inventory items from the first and second mobile drive units.

28. The system of claim 14, wherein the plurality of inventory holders comprise:

a plurality of first inventory holders having third dimensions;

a plurality of second inventory holders having fourth dimensions, wherein the third and fourth dimensions are different;

the first mobile drive unit is further operable to transport the plurality of first inventory holders; and

the second mobile drive unit is further operable to transport the plurality of second inventory holders.

29. The system of claim 28, wherein the first mobile drive unit is further operable to transport the second inventory holders.

30. The system of claim 28, wherein the second mobile drive unit is further operable to transport the first inventory holders.

31. A management module comprising logic encoded in a non-transitory medium and when executed by a processor operable to:

facilitate management of a first mobile drive unit having first dimensions in an inventory management system;

facilitate management of a second mobile drive unit having second dimensions in the inventory management system, wherein the first and second dimensions are different; and

maintain a three-dimensional reservation space in which the first mobile drive unit is operable to reserve a first three-dimensional reservation volume corresponding to the first dimensions and the second mobile drive unit is operable to reserve a second three-dimensional reservation volume corresponding to the second dimensions; and

wherein the first and second mobile drive units are operable to transport inventory items to a plurality of inventory stations in the inventory management system.

32. The management module of claim 31, further operable to:

determine a first path for the first mobile drive unit;

determine a second path for the second mobile drive unit; and

reserve a first segment of the first path, the first segment comprising a first space associated with the first dimensions of the first mobile drive unit.

33. The management module of claim 32, wherein the first space comprises one of a volume, a cell, and a footprint.

34. The management module of claim 32, further operable to:

receive a request to reserve a second segment of a second path;

determine whether the requested second segment intersects with a reserved space; and

determine that the requested second segment does not intersect with the reserved space.

35. The management module of claim 32, further operable to:

determine that the first mobile drive unit is coupled to an inventory holder;

modify the first space based on the dimensions of the inventory holder; and

reserve a modified first segment comprising the modified first space.

36. The management module of claim 32, further operable to:

apply a reservation policy, wherein reserving the first segment is based on determining that the reservation does not conflict with the reservation policy.

37. The management module of claim 36, wherein the reservation policy is based on at least one of an inventory holder location, a predetermined number of maximum drives, a predetermined maximum weight, a predetermined maximum speed, and an inventory type.

38. The management module of claim 32, further operable to:

receive a request to reserve the first segment of the first path, the first segment representing a physical location of an inventory holder;

determine that the first segment does not intersect with the inventory holder; and

wherein after reserving the first segment, the first mobile drive unit moves under the inventory holder.

39. The management module of claim 32, further operable to:

receive a request to reserve the first segment of the first path;

determine that the requested first segment comprises a partially reserved portion and a partially unreserved portion; and

partially grant the request of the partially unreserved portion.

40. The management module of claim 31, further operable to:

determine a capability of one of the plurality of inventory stations; and

assign an order associated with the first and second mobile drive units to the inventory station based on the capability.

41. The management module of claim 32, further operable to:

receive a request to reserve the first segment of the first path;

determine that the requested first segment comprises a partially reserved portion and a partially unreserved portion;

partially grant the request of the partially unreserved portion;

further determine that an additional portion of the partially reserved portion has become unreserved; and

partially grant the request of the additional portion.

42. The management module of claim 41, further operable to:

determine that the additional portion conflicts with a reservation policy; and

reduce the additional portion based on the reservation policy.