Generating a Path for a Mobile Drive Unit

• US 20130304253A1
• Filed: 07/16/2013
• Published: 11/14/2013
• 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: WURMAN, PETER R., D'ANDREA, RAFFAELLO, BARBEHENN, MICHAEL T., HOFFMAN, ANDREW EDWARD, MOUNTZ, MICHAEL CORDELL
• Granted Patent: US 8,930,133 B2
• Time in Patent Office: Days
• US Class Current: 700/214
• CPC Class Codes: G05D 1/0297 by controlling means in a control room
• CPC Class Codes: G05D 2201/0216 Vehicle for transporting goods in a warehouse, factory or similar
• CPC Class Codes: G05D 3/00 Control of position or direction G05D1/00 takes precedence; numerical control to execute positioning G05B19/18
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders
• CPC Class Codes: G06Q 50/30 Transportation; Communications
• CPC Class Codes: G06Q 50/40 Business processes related to the transportation industry shipping G06Q10/083

Abstract

A system for transporting inventory items includes an inventory holder and a mobile drive unit. The inventory holder has a frame with device openings. The mobile drive unit is operable to dock with an inventory holder and undock with an inventory holder. When undocked from an inventory holder, the mobile drive unit is further operable to traverse a path from a first location to a second location. The path passes through at least a first device opening of the inventory holder such that the mobile drive unit passes beneath the inventory holder while moving along the path.

Claims

1-22. -22. (canceled)

23. A system for transporting inventory items, comprising:

an inventory holder comprising;

a frame;

one or more device openings formed in the frame; and

a mobile drive unit operable to;

dock with one of a plurality of inventory holders;

undock from one of the plurality of inventory holders; and

traverse a path from a first location to a second location while undocked, wherein the path passes through at least a first device opening of the one or more device openings such that the mobile drive unit passes beneath the inventory holder while moving along the path from the first location to the second location.

24. The system of claim 23, wherein the path comprises a first path and the mobile drive unit is further operable to traverse a second path from the first location to the second location while docked, wherein the second path avoids the plurality of inventory holders.

25. The system of claim 24, wherein the mobile drive unit traverses the first path from the first location to the second location based at least in part upon a determination that the mobile drive unit is undocked and the mobile drive unit traverses the second path from the first location to the second location based at least in part upon a determination that the mobile drive unit is docked.

26. The system of claim 24, further comprising a management module operable to:

receive a route request from a mobile drive unit, the route request identifying a destination location;

determine a state of the mobile drive unit, the state comprising docked or undocked;

in response to determining that the state of the mobile drive unit is undocked, generate the first path to the destination; and

in response to determining that the state of the mobile drive unit is docked, generate the second path to the destination.

27. The system of claim 23, wherein the inventory holder comprises a first inventory holder, the second location comprises a storage location, and the system further comprises a second inventory holder at the storage location, and the mobile drive unit is further operable to:

traverse the first path to the storage location in response to a determination that the second inventory holder is to be transported to an inventory station;

dock with the second inventory holder at the second location; and

traverse a second path from the storage location to the inventory station, wherein the second path avoids the plurality of inventory holders while moving to the inventory station.

28. A method of transporting inventory items, comprising:

undocking, by a mobile drive unit, from a first inventory holder at a first location;

receiving, from a management module, instructions to move to a second inventory holder at a second location, the instructions generated by the management module in response to determining that the mobile drive unit is undo eked;

passing, by the mobile drive unit, beneath a plurality of inventory holders while moving to the second location; and

docking with the second inventory holder at the second location.

29. The method of claim 28, wherein the mobile drive unit is disposed within a workspace comprising a plurality of cells and the instructions comprise a path that crosses a plurality of first cells;

and

wherein the plurality of first cells are selected by the management module to be included in the path based at least in part upon one or more attributes of the first cells and a state of the mobile drive unit.

30. The method of claim 29, wherein the state of the mobile drive unit is indicative of one or more dimensions associated with the mobile drive unit.

31. The method of claim 29, wherein the one or more attributes of the first cells comprises a dimension restriction and the state of the mobile drive unit indicates a dimension required by the mobile drive unit to move through the plurality of cells.

32. The method of claim 31, wherein the dimension restriction comprises one or more of a height limit and a width limit and the dimension required by the mobile drive unit comprises one or more of a height and width required by the mobile drive unit to move through the plurality of cells.

33. The method of claim 31, wherein the dimension required by the mobile drive unit to move through the plurality of cells depends on whether the mobile drive unit is transporting an inventory holder.

34. The method of claim 28, further comprising:

transmitting, by the mobile drive unit, first information identifying a state of the mobile drive unit to the management module;

transmitting, by the mobile drive unit, second information comprising a route request to the management module; and

receiving a path the path generated based at least in part upon the state of the mobile drive unit.

35. The method of claim 28, wherein docking with the second inventory holder comprises:

positioning the mobile drive unit beneath the second inventory holder; and

raising a docking head of the mobile drive unit towards the second inventory holder.

36. A management module, operable to

receive, by a processor, a route request from a mobile drive unit, wherein the mobile drive unit is located at a first location and the route request comprises a second location;

determine, by the processor, a state associated with the mobile drive unit, wherein the state comprises one or more first dimensions associated with the mobile drive unit;

access attributes associated with one or more cells of a workspace, wherein the attributes comprise one or more second dimensions;

determine, by the processor, a path from the first location to the second location based at least upon the one or more first dimensions and the one or more second dimensions; and

transmit, by an interface, the path to the mobile drive unit.

37. The management module of claim 36, wherein the one or more first dimensions comprises a height associated with the mobile drive unit and a width associated with the mobile drive unit and the one or more second dimensions comprises a height restriction and a width restriction associated with the one or more cells.

38. The management module of claim 37, wherein determining the path further comprises:

comparing the height associated with the mobile drive unit with a height restriction of one or more cells;

comparing the width associated with the mobile drive unit with a width restriction of the one or more cells; and

generating the path based at least upon the comparison of the height associated with the mobile drive unit with the height restriction of one or more cells and the comparison of the width associated with the mobile drive unit with the width restriction of the one or more cells.

39. The management module of claim 36, wherein determining the state associated with the mobile drive unit further comprises:

receiving information from the mobile drive unit identifying the state of the mobile drive unit;

storing the received information; and

identifying the state of the mobile drive unit based on the stored information.

40. The management module of claim 36, wherein the second location comprises one of the following:

a location associated with one of a plurality of inventory holders;

a location associated with an inventory station;

a storage location; and

a rotation area.

41. The management module of claim 36, wherein:

the attributes associated with the one or more cells further comprise a traffic measurement; and

determining the path further comprises;

comparing the traffic measurement of the one or more cells with a traffic threshold; and

based upon the comparison of the traffic measurement of the one or more cells with the traffic threshold, generating the path.

42. The management module of claim 41, wherein the path avoids one or more of the one or more cells based at least upon a determination that the traffic measurement of the one or more of the one or more cells exceeds the traffic threshold.