Inventory holder load detection and/or stabilization

• US 9,280,153 B1
• Filed: 09/19/2014
• Issued: 03/08/2016
• Est. Priority Date: 09/19/2014
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Palamarchuk, Andriy, Brazeau, Jeremiah David
• Primary Examiner(s): Cumbess, Yolanda
• Application Number:
  US14/491,752
• Time in Patent Office: 536 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B65G 1/137 with arrangements or automatic control means for selecting which articles are to be removed
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G05D 1/00 Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots drive control systems specially adapted for autonomous road vehicles B60W60/00
• 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

Abstract

An inventory system includes an inventory holder and a mobile drive unit. The mobile drive unit includes sensors for detecting one or more load characteristics of the inventory holder and/or includes magnets and/or magnetic surfaces for securing the inventory holder to the mobile drive unit during lifting and/or moving.

Claims

1. An inventory management system, comprising:

an inventory holder configured to store inventory items, the inventory holder comprising a frame having a ferromagnetic surface, the inventory holder further having a center of mass dependent on a distribution of inventory items stored in the inventory holder;

a mobile drive unit configured to lift and move the inventory holder, the mobile drive unit comprising;

a drive module comprising one or more wheels configured to propel the mobile drive unit; and

a docking head configured to engage the frame for lifting, the docking head comprising one or more magnets arranged so as to engage with the ferromagnetic surface of the inventory holder when the mobile drive unit is lifting the inventory holder, the one or more magnets configured to (i) secure the inventory holder to the mobile drive unit during lifting and/or moving by the mobile drive unit, and (ii) provide information about a position of the center of mass of the inventory holder relative to mobile drive unit when lifted by the mobile drive unit; and

a management module configured to at least instruct the mobile drive unit to lift and move the inventory holder.

2. The inventory management system of claim 1, wherein the docking head comprises:

a first set of magnets configured to secure the inventory holder to the mobile drive unit during lifting and/or moving by the mobile drive unit; and

a second set of magnets configured to provide information about the position of the center of mass of the inventory holder relative to mobile drive unit when lifted by the mobile drive unit.

3. The inventory management system of claim 1, wherein the management module is further configured to determine that the inventory holder is connected to the mobile drive unit based on the provided information about the position of the center of mass of the inventory holder relative to mobile drive unit.

4. The inventory management system of claim 1, wherein the management module is further configured to determine that the inventory holder is unbalanced relative to the mobile drive unit based on the provided information about the position of the center of mass of the inventory holder relative to mobile drive unit.

5. The inventory management system of claim 1, wherein the management module is further configured to determine that the inventory holder is tipping over or has tipped over relative to the mobile drive unit based on the provided information about the position of the center of mass of the inventory holder relative to mobile drive unit.

6. An inventory system comprising:

an inventory holder configured to store inventory items, the inventory holder further having a load distribution dependent on a distribution of inventory items stored in the inventory holder;

a mobile drive unit configured to dock with the inventory holder for movement of the inventory holder by the mobile drive unit, the mobile drive unit comprising a sensor configured to obtain information about the load distribution of the inventory holder relative to the mobile drive unit; and

a management module configured to provide instructions to the mobile drive unit based on information obtained by the sensor.

7. The inventory system of claim 6, wherein the sensor comprises an imaging device configured to detect a change in position of a reference item associated with a surface of the inventory holder, the change resulting from differences in the load distribution.

8. The inventory system of claim 6, wherein the sensor comprises electrical sensors configured to detect differences in electrical connectivity between the mobile drive unit and a surface of the inventory holder resulting from differences in the load distribution.

9. The inventory system of claim 6, wherein the sensor comprises pressure sensors configured to detect differences in pressure on the mobile drive unit resulting from differences in the load distribution.

10. The inventory system of claim 6, wherein the sensor comprises magnets configured for detecting differences in magnetic fields resulting from differences in the load distribution.

11. The inventory system of claim 6, wherein the management module is further configured to instruct the mobile drive unit to disengage the inventory holder and re-engage the inventory holder at a different position for lifting based on information obtained by the sensor.

12. The inventory system of claim 6, wherein the management module is further configured to instruct the mobile drive unit to retain the inventory holder in a lifted state based on information obtained by the sensor.

13. The inventory system of claim 6, wherein the management module is further configured to, based on information obtained by the sensor, instruct the mobile drive unit to move abruptly so as to move at least one inventory item stored by the inventory holder.

14. The inventory system of claim 6, wherein the management module is further configured to instruct the mobile drive unit to vary a speed of travel of the mobile drive unit based on information obtained by the sensor.

15. The inventory system of claim 6, wherein the management module is further configured to instruct the mobile drive unit to alter a destination based on information obtained by the sensor.

16. The inventory system of claim 6, wherein the management module is further configured to:

determine measured load distribution information about the inventory holder and items stored therein based on information obtained by the sensor; and

evaluate estimated weight information about an estimated weight of the inventory items stored in the inventory holder based on the measured load distribution information.

17. An inventory system comprising:

a workspace;

an inventory holder configured to store inventory items, the inventory holder comprising a frame; and

a mobile drive unit comprising a propulsion system for moving the mobile drive unit between locations of the workspace, the mobile drive unit configured to couple with the inventory holder for movement of the inventory holder between locations of the workspace by the propulsion system of the mobile drive unit;

wherein one of the frame of the inventory holder or the mobile drive unit comprises a ferromagnetic surface; and

wherein another of the frame of the inventory holder or the mobile drive unit comprises one or more magnets, the one or more magnets configured to magnetically couple with the ferromagnetic surface so as to improve a strength with which the mobile drive unit couples with the inventory holder for movement of the inventory holder.

18. The inventory system of claim 17, wherein said one or more magnets comprise one or more permanent magnets having a combined magnetic force less than a weight of the mobile drive unit.

19. The inventory system of claim 17, wherein said one or more magnets comprise one or more electromagnets configured to, when activated, secure the inventory holder to the mobile drive unit.

20. The inventory system of claim 17, wherein said one or more magnets comprise one or more permanent magnets configured to magnetically couple the mobile drive unit with the inventory holder and one or more electromagnets configured to, when activated, magnetically decouple the mobile drive unit from the inventory holder.