Controlling mobile drive units with active markers

• US 8,918,202 B2
• Filed: 08/21/2012
• Issued: 12/23/2014
• Est. Priority Date: 08/21/2012
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Kawano, Yasushi
• Primary Examiner(s): CUMBESS, YOLANDA RENEE
• Application Number:
  US13/590,547
• Publication Number:
  US 20140058556A1
• Time in Patent Office: 854 Days
• Field of Search: None
• US Class Current: 700/216
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70
• CPC Class Codes: G05D 1/0261 using magnetic plots
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30
• CPC Class Codes: G05D 1/0297 by controlling means in a control room

Abstract

A method of controlling a mobile drive unit includes detecting, by a mobile drive unit at a first location, an active marker at the first location. The mobile drive unit is a self-powered robotic device configured to move independently in a workspace in response to instructions received from the active marker. A management module transmits an instruction to the active marker. The active marker emits a signal detectable by the mobile drive unit, the signal comprising the instruction. The mobile drive unit receives the instruction from the active marker for the mobile drive unit to perform a task.

Claims

1. A system of controlling a mobile drive unit with active markers, comprising:

a plurality of active markers in a two-dimensional pattern of active markers, an active marker operable to emit one or more instructions to a mobile drive unit proximate to the active marker;

a management module operable to send instructions to the plurality of active markers;

a mobile drive unit operable to;

receive, at a first location, a signal emitted by the active marker at the first location;

analyze the signal to determine an instruction, the instruction comprising directions to move to a second location;

based on the instruction, move to the second location according to the instructions.

2. The system of claim 1, wherein:

the second location comprises a storage location of an inventory holder;

the instruction further comprises a first instruction to lift the inventory holder at the storage location; and

the mobile drive unit is further operable to;

receive a second instruction from a second active marker at the storage location, the second instruction comprising directions to move the inventory holder to an inventory station.

3. The system of claim 2, the mobile drive unit further operable to:

receive a third instruction from a third active marker at the inventory station, the third instruction comprising directions to move the inventory holder to a shipping location, the mobile drive unit operable to undock from the inventory holder at the shipping location.

4. The system of claim 1, the management module further operable to:

receive a plurality of orders for inventory items stored by a plurality of inventory holders within a workspace;

determine a plurality of paths for a each of a plurality of mobile drive units to retrieve one of the inventory holders and transport the inventory holder to an inventory station; and

control each of the plurality of mobile drive units by transmitting instructions to the plurality of active markers such that a particular mobile drive unit receives a particular instruction from a particular active marker to proceed along a portion of a particular path as the particular mobile drive unit proceeds along the particular path.

5. The system of claim 1, wherein the two-dimensional pattern of active markers are disposed above the mobile drive unit.

6. A method of controlling a mobile drive unit, comprising:

detecting, by a mobile drive unit at a first location, an active marker at the first location, the mobile drive unit comprising a self-powered robotic device configured to move independently in a workspace in response to instructions received from the active marker;

transmitting, by a management module, an instruction to the active marker;

emitting, by the active marker, a signal detectable by the mobile drive unit, the signal comprising the instruction;

receiving, by the mobile drive unit, the instruction from the active marker for the mobile drive unit to perform a task.

7. The method of claim 6, further comprising receiving direction instructions from the active marker.

8. The method of claim 7, further comprising moving the mobile drive unit to a second location according to the direction instructions.

9. The method of claim 6, wherein the signal comprises a light signal.

10. The method of claim 6, wherein the task is associated with lifting an inventory holder and transporting the inventory holder to a second location.

11. The method of claim 6, further comprising transmitting information from the mobile drive unit to the active marker, the information comprises a status of the mobile drive unit.

12. The method claim 6, further comprising:

detecting, by the mobile drive unit, that an obstacle is blocking a path of the mobile drive unit; and

determining a path to avoid the obstacle.

13. The method of claim 12, wherein the path to avoid the obstacle is calculated by the mobile drive unit.

14. The method of claim 6, wherein the active marker is one of a plurality of active markers arranged in a two dimensional grid in a fulfillment facility.

15. The method of claim 14, wherein the active marker comprises a first active marker and the method further comprises:

determining, by the management module, a path from the first location to a second active marker;

wherein transmitting, by the management module, the instruction to the active marker comprises transmitting an instruction to the first active marker for the mobile drive unit to move along at least a portion of the path to the second active marker.

16. The method of claim 14, wherein the active marker comprises a first active marker and the method further comprises:

determining, by the management module, a path from the first location to a second location, the path comprising a first segment from the first active marker to a second active marker in the two-dimensional grid and a second segment from the second active marker to a third active marker in the two-dimensional grid;

transmitting, by the management module, a first instruction for the mobile drive unit to move along the first segment to the first active marker and a second instruction for the mobile drive unit to move along the second segment to the second active marker.

17. The method of claim 6, further comprising:

determining, by the management module, an optimal path for mobile drive unit to transport an inventory holder to an inventory station.

18. A system for controlling a mobile drive unit with active markers, comprising:

a first mobile drive unit; and

an active marker operable to;

communicate information indicating a location of the first mobile drive unit when the first mobile drive unit is proximate to the active marker; and

transmit an instruction to the first mobile drive unit when the first mobile drive unit is proximate to the active marker, the instruction associated with a task for the mobile drive unit to perform.

19. The system of claim 18, wherein the first mobile drive unit is operable to:

receive the instruction from the active marker, the instruction to transport an inventory holder to a second location; and

transport the inventory holder to the second location based on the instruction.

20. The system of claim 18, wherein the active marker is further operable to:

communicate at least a portion of a path within a workspace to the mobile drive unit; and

wherein the instruction is for the mobile drive unit to proceed along the path from the location.

21. The system of claim 18, further comprising a second mobile drive unit operable to transmit information to the active marker, wherein the active maker is operable to communicate the instruction to the first mobile drive unit based on information received from the second mobile drive unit.

22. The system of claim 21, wherein the second mobile drive unit is further operable to receive tasks from a management module, the tasks associated with a plurality of mobile drive units.