System and Method for Positioning a Mobile Drive Unit

• US 20120143427A1
• Filed: 01/23/2012
• Published: 06/07/2012
• Est. Priority Date: 06/19/2006
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Kiva Systems, Inc (Amazon.com, Inc.)
• Inventors: Hoffman, Andrew E., Barbehenn, Michael T., Mountz, Michael C., Wurman, Peter R., D'Andrea, Raffaello
• Granted Patent: US 9,087,314 B2
• Time in Patent Office: Days
• US Class Current: 701/23
• 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 2219/31004 Move vehicle to battery charge or maintenance area
• CPC Class Codes: G05B 2219/31005 Detect obstacles on path of vehicle
• CPC Class Codes: G05B 2219/31006 Monitoring of vehicle
• CPC Class Codes: G05D 1/0217 in accordance with energy consumption, time reduction or distance reduction criteria
• 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
• 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

Abstract

A method for transporting inventory items includes determining an assignment state of a mobile drive unit. The method also includes selecting a location for the mobile drive unit based on the assignment state of the mobile drive unit, in response to determining that the mobile drive unit is not currently completing a task. The method further includes transmitting information to the mobile drive unit identifying the selected location.

Claims

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29. A system for transporting inventory items, comprising:

a mobile drive unit;

a plurality of inventory holders; and

a management module operable to;

determine a capability state of a mobile drive unit;

select a location for the mobile drive unit based on the capability state of the mobile drive unit; and

transmit information to the mobile drive unit identifying the selected location.

30. The system of claim 29, wherein the mobile drive unit is further operable to move to the selected location.

31. The system of claim 29, wherein the mobile drive unit is further operable to park at the selected location until the mobile drive unit receives an additional instruction.

32. The system of claim 29, wherein the management module is operable to determine the capability state of the mobile drive unit by determining that the mobile drive unit is not capable of completing a particular type of task.

33. The system of claim 29, wherein the management module is operable to determine the capability state of the mobile drive unit by determining a charge on a battery associated with the mobile drive unit.

34. The system of claim 33, further comprising an energy station operable to recharge batteries associated with mobile drive units, and wherein the management module is operable to select the location for the mobile drive unit by selecting a location based on a distance between the location and the energy station.

35. The system of claim 29, wherein the management module is operable to:

determine the capability state of the mobile drive unit by detecting a degraded capability of the mobile drive unit, and

select a location for the mobile drive unit based on the capability state of the mobile drive unit by selecting a destination for an inventory holder associated with the degraded capability.

36. The system of claim 29, wherein the management module is operable to determine the capability state of the mobile drive unit by detecting a fuel level associated with the mobile drive unit.

37. The system of claim 29, further comprising an energy station operable to refuel mobile drive units, and wherein the management module is operable to select the location for the mobile drive unit by selecting a location based on a distance between the location and the energy station.

38. The system of claim 29, wherein the management module is operable to determine the capability state of the mobile drive unit by determining that the mobile drive unit is unable to carry an inventory holder.

39. The system of claim 29, wherein the management module is operable to determine the capability state of the mobile drive unit by determining that the mobile drive unit is unable to dock with an inventory holder.

40. The system of claim 29, wherein the management module is operable to determine a capability state of the mobile drive unit that the mobile drive unit is unable to carry an inventory holder.

41. The system of claim 29, wherein the management module is operable to determine a capability state of the mobile drive unit by detecting that the mobile drive unit needs to be repaired.

42. The system of claim 41, wherein the management module is operable to select a location for the mobile drive unit by selecting a location based on a distance between the location and a repair station.

43. The system of claim 41, wherein the management module is operable to determine a capability state of the mobile drive unit by detecting that the mobile drive unit needs a particular type of repair.

44. The system of claim 43, wherein the management module is operable to select the location for the mobile drive unit by selecting a location based on a distance between the location and a repair station operable to perform the type of repair needed by the mobile drive unit.

45. The system of claim 41, wherein the management module is operable to determine a capability state of the mobile drive unit by detecting that the mobile drive unit needs a particular type of maintenance.

46. The system of claim 45, wherein the management module is operable to select the location for the mobile drive unit by selecting a location based on a distance between the location and a maintenance station operable to perform the type of maintenance needed by the mobile drive unit.

47. The system of claim 29, wherein the management module is operable to select a location for the mobile drive unit by selecting a location in a workspace in which the mobile drive unit is operating based on a distance between the selected location and an access point to the workspace.

48. The system of claim 29, wherein the management module is operable to select a location for the mobile drive unit by selecting a location based on a traffic level associated with the location.

49. The system of claim 29, wherein the management module is operable to select a location for the mobile drive unit by selecting a location that is not otherwise available for mobile drive units to move through.

50. The system of claim 29, wherein the management module is operable to select a location for the mobile drive unit by selecting a location that is not otherwise available as a destination for mobile drive units.

51. The system of claim 29, wherein the selected location comprises a first selected location, and wherein the management module is further operable to:

detect a change in a state of an inventory system in which the mobile drive unit is operating;

in response to detecting the change in the state of the inventory system, select a second location for the mobile drive unit based on the capability state of the mobile drive unit; and

transmit information to the mobile drive unit identifying the second selected location.

52. The system of claim 51, wherein the management module is operable to detect the change in the state of the inventory system by detecting that another mobile drive unit is attempting to move through the first selected location.

53. The system of claim 51, wherein the management module is operable to detect the change in the state of the inventory system by detecting that the first selected destination is a current destination for another mobile drive unit.

54. A method for transporting inventory items, comprising:

determining a capability state of a mobile drive unit;

selecting a location for the mobile drive unit based on the capability state of the mobile drive unit; and

transmitting information to the mobile drive unit identifying the selected location.

55. The method of claim 54, wherein further comprising moving the mobile drive unit to the selected location.

56. The method of claim 54, further comprising parking the mobile drive unit at the selected location until the mobile drive unit receives an additional instruction.

57. The method of claim 54, wherein determining the capability state of the mobile drive unit comprises determining that the mobile drive unit is not capable of completing a particular type of task.

58. The method of claim 54, wherein determining the capability state of the mobile drive unit comprises determining a charge on a battery associated with the mobile drive unit.

59. The method of claim 58, wherein selecting the location for the mobile drive unit comprises selecting a location based on a distance between the location and the energy station, wherein the energy station is operable to recharge batteries associated with the mobile drive units.

60. The method of claim 54, wherein determining the capability state of the mobile drive unit comprises detecting a degraded capability of the mobile drive unit, and wherein selecting a location for the mobile drive unit based on the capability state of the mobile drive unit comprises selecting a destination for an inventory holder associated with the degraded capability.

61. The method of claim 54, wherein determining the capability state of the mobile drive unit comprises determining a fuel level associated with the mobile drive unit.

62. The method of claim 54, wherein selecting the location for the mobile drive unit comprises selecting a location based on a distance between the location and the energy station wherein the energy station is operable to refuel mobile drive units.

63. The method of claim 54, wherein determining the capability state of the mobile drive unit comprises determining that the mobile drive unit is unable to carry an inventory holder.

64. The method of claim 54, wherein determining the capability state of the mobile drive unit comprises determining that the mobile drive unit is unable to dock with an inventory holder.

65. The method of claim 54, wherein determining the capability state of the mobile drive unit comprises determining that the mobile drive unit is unable to carry an inventory holder.

66. The method of claim 54, wherein determining the capability state of the mobile drive unit comprises detecting that the mobile drive unit needs to be repaired.

67. The method of claim 66, wherein selecting the location for the mobile drive unit comprises selecting a location based on a distance between the location and a repair station.

68. The method of claim 66, wherein determining the capability state of the mobile drive unit comprises detecting that the mobile drive unit needs a particular type of repair.

69. The method of claim 68, wherein selecting the location for the mobile drive unit comprises selecting a location based on a distance between the location and a repair station operable to perform the type of repair needed by the mobile drive unit.

70. The method of claim 54, wherein determining the capability state of the mobile drive unit comprises detecting that the mobile drive unit needs a particular type of maintenance.

71. The method of claim 54, wherein selecting the location for the mobile drive unit comprises selecting a location based on a distance between the location and a maintenance station operable to perform the type of maintenance needed by the mobile drive unit.

72. The method of claim 54, wherein the selecting the location for the mobile drive unit comprises selecting a location in a workspace in which the mobile drive unit is operating based on a distance between the selected location and an access point to the workspace.

73. The method of claim 54, wherein selecting a location for the mobile drive unit comprises selecting a location based on a traffic level associated with the location.

74. The method of claim 54, wherein selecting a location for the mobile drive unit comprises selecting a location that is not otherwise available for mobile drive units to move through.

75. The method of claim 54, wherein selecting a location for the mobile drive unit comprises selecting a location that is not otherwise available as a destination for mobile drive units.

76. The method of claim 54, wherein the selected location comprises a first selected location, and further comprising:

detecting a change in a state of an inventory system in which the mobile drive unit is operating;

in response to detecting the change in the state of the inventory system, selecting a second location for the mobile drive unit based on the capability state of the mobile drive unit; and

transmitting information to the mobile drive unit identifying the second selected location.

77. The method of claim 76, wherein the management module is operable to detect the change in the state of the inventory system by detecting that another mobile drive unit is attempting to move through the first selected location.

78. The method of claim 76, wherein detecting the change in the state of the inventory system comprises detecting that the first selected destination is a current destination for another mobile drive unit.

79. A management module operable to:

determining a capability state of a mobile drive unit;

selecting a location for the mobile drive unit based on the capability state of the mobile drive unit; and

transmitting information to the mobile drive unit identifying the selected location.

80. A system for transporting inventory items, comprising:

means for determining a capability state of a mobile drive unit;

means for selecting a location for the mobile drive unit based on the capability state of the mobile drive unit; and

means for transmitting information to the mobile drive unit identifying the selected location.

81. A system for transporting inventory items, comprising:

a mobile drive unit;

a plurality of inventory holders; and

a management module operable to;

determine an assignment state of a mobile drive unit;

in response to determining that the mobile drive unit is not currently completing a task, select a location for the mobile drive unit based on the assignment state of the mobile drive unit, wherein selecting a location is based on at least one of the following;

selecting a location that is currently storing an inventory holder;

selecting a location that is not otherwise available for mobile drive units to move through;

selecting a location that is not otherwise available as a destination for mobile drive units;

selecting a location based on a distance from the selected location to a particular inventory holder;

and

selecting a location based on a distance from the selected location to a particular group of inventory holders; and

transmit information to the mobile drive unit identifying the selected location.

82. A method for transporting inventory items, comprising:

determining an assignment state of a mobile drive unit;

in response to determining that the mobile drive unit is not currently completing a task, selecting a location for the mobile drive unit based on the assignment state of the mobile drive unit, wherein selecting the location is based on at least one of the following;

selecting a location that is currently storing an inventory holder;

selecting a location that is not otherwise available for mobile drive units to move through;

selecting a location that is not otherwise available as a destination for mobile drive units;

selecting a location based on a distance from the selected location to a particular inventory holder; and

selecting a location based on a distance from the selected location to a particular group of inventory holders; and

transmitting information to the mobile drive unit identifying the selected location.