System and method for coordinating movement of mobile drive units

• US 9,448,560 B2
• Filed: 04/25/2014
• Issued: 09/20/2016
• Est. Priority Date: 06/19/2006
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: D'Andrea, Raffaello, Wurman, Peter R., Barbehenn, Michael T., Hoffman, Andrew E., Mountz, Michael C.
• Primary Examiner(s): MOYER, DALE S
• Application Number:
  US14/262,354
• Publication Number:
  US 20140236413A1
• Time in Patent Office: 879 Days
• Field of Search: 701 23- 28, 901/1
• US Class Current: 1/1
• CPC Class Codes: G05B 19/41895 using automatic guided vehicles [AGV] control of position or course of AGV's G05D1/00
• CPC Class Codes: G05B 2219/31003 Supervise route, reserve route and allocate route to vehicle, avoid collision
• CPC Class Codes: G05B 2219/45056 Handling cases, boxes
• CPC Class Codes: G05D 1/0212 with means for defining a desired trajectory involving a plurality of land vehicles G05D1/0287
• CPC Class Codes: G05D 1/0291 Fleet control monitoring fleets in traffic control systems for road vehicles G08G1/127, G08G1/127
• CPC Class Codes: G05D 1/0297 by controlling means in a control room
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
• CPC Class Codes: Y02P 90/60 Electric or hybrid propulsion means for production processes

Abstract

A method for moving one or more mobile drive units within a workspace includes receiving, from a first mobile drive unit, a reservation request requesting use of a first path segment to move in a first direction. The method further includes determining that a second mobile drive unit is currently located on the first path segment and determining whether the second mobile drive unit is moving in the first direction. Additionally, the method includes transmitting a reservation response indicating that the reservation request is denied, in response to determining that the second mobile drive unit is not moving in the first direction. The method also includes transmitting a reservation response indicating that the reservation request is granted, in response to determining that the second mobile drive unit is moving in the first direction.

Claims

1. A method for inventory management, comprising:

deploying a first mobile drive unit having first dimensions;

deploying a second mobile drive unit having second dimensions, wherein the first and second dimensions are different such that the first mobile drive unit and the second mobile drive unit are different sizes; 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;

determining a first path for the first mobile drive unit;

determining a second path for the second mobile drive unit;

reserving a first segment of the first path, the first segment comprising a first space based at least in part on the first dimensions of the first mobile drive unit;

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

determining that the requested second segment is not a reserved space.

2. A method for inventory management, comprising:

deploying a first mobile drive unit having first dimensions;

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

determining a first path for the first mobile drive unit;

determining a second path for the second mobile drive unit;

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, wherein reserving the first segment further comprises;

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

modifying a state associated with the first mobile drive unit based on a dimension of the inventory holder; and

identifying the first path for the first mobile drive unit based on the state.

3. The method of claim 2, wherein reserving the 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;

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

4. A method for inventory management, comprising:

deploying a first mobile drive unit having first dimensions;

deploying a second mobile drive unit having second dimensions, wherein the first and second dimensions are different such that the first mobile drive unit and the second mobile drive unit are different sizes; 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;

determining a first path for the first mobile drive unit;

determining a second path for the second mobile drive unit;

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, wherein reserving the 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.

5. 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 such that the first mobile drive unit and the second mobile drive unit are different sizes;

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

a management module operable to apply a reservation policy, wherein reserving a first segment is based on determining that the reservation does not conflict with the reservation policy; and

the management module is further operable to reserve the first segment of a first path, the first segment comprising a first space associated with the first dimensions of the first mobile drive unit.

6. The system of claim 5, wherein the management module is further operable to:

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

determine a second path for the second mobile drive unit.

7. The system of claim 5, wherein the management module is 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;

wherein after reserving the first segment, the first mobile drive unit docks with the inventory holder.

8. 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 such that the first mobile drive unit and the second mobile drive unit are different sizes;

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

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 by;

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.

9. The system of claim 8, the management module further operable to:

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

reduce the additional portion based on the reservation policy.

10. 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 such that the first mobile drive unit and the second mobile drive unit are different sizes;

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;

apply a reservation policy, wherein the reservation policy defines a scheme for granting or denying a reservation request for a particular number of segments of a path; and

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

11. The management module of claim 10, further operable to:

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

determine a second path for the second mobile drive unit.

12. The management module of claim 10, wherein the first and second mobile drive units are operable to traverse segments of a grid-based workspace by reserving particular segments comprising at least a portion of particular assigned paths within the workspace.

13. The management module of claim 10, wherein the first and second mobile drive units are each operable to transport at least one of a plurality of inventory holders to at least one of the plurality of inventory stations.

14. The management module of claim 10, 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; and

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

15. The management module of claim 10, wherein the first dimensions of the first mobile drive unit correspond to a particular height and a particular weight.