Inventory holder load detection and/or stabilization

• US 9,469,477 B1
• Filed: 01/27/2016
• Issued: 10/18/2016
• 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:
  US15/008,378
• Time in Patent Office: 265 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. A 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 a frame of an inventory holder for lifting the inventory holder, the inventory holder having a center of mass dependent on a distribution of any inventory items stored in the inventory holder, the docking head comprising one or more magnets arranged so as to engage with a ferromagnetic surface of the frame 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 the mobile drive unit when lifted by the mobile drive unit.

2. The mobile drive unit 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 mobile drive unit of claim 1, wherein the mobile drive unit further comprises a module configured to at least one of receive or generate a determination that the inventory holder is connected to the mobile drive unit, the determination based on the provided information about the position of the center of mass of the inventory holder relative to mobile drive unit.

4. The mobile drive unit of claim 1, wherein the mobile drive unit further comprises a module configured to at least one of receive or generate a determination that the inventory holder is unbalanced relative to the mobile drive unit, the determination based on the provided information about the position of the center of mass of the inventory holder relative to mobile drive unit.

5. The mobile drive unit of claim 1, wherein the mobile drive unit further comprises a module configured to at least one of receive or generate a determination that the inventory holder is tipping over or has tipped over relative to the mobile drive unit, the determination based on the provided information about the position of the center of mass of the inventory holder relative to mobile drive unit.

6. A mobile drive unit comprising:

a drive module comprising a propulsion system configured to move the mobile drive unit between locations of a workspace;

a docking head configured to dock with an inventory holder for movement of the inventory holder by the mobile drive unit, the inventory holder having a center of mass dependent on a distribution of any inventory items stored in the inventory holder;

a sensor configured to obtain information about a load distribution of the inventory holder relative to the mobile drive unit, and

a module configured to at least one of receive or generate instructions based on the information obtained by the sensor.

7. The mobile drive unit 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 the load distribution of the inventory holder relative to the mobile drive unit.

8. The mobile drive unit 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 the load distribution of the inventory holder relative to the mobile drive unit.

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

10. The mobile drive unit of claim 6, wherein the sensor comprises magnets configured to detect differences in magnetic fields between the mobile drive unit and a surface of the inventory holder resulting from the load distribution of the inventory holder relative to the mobile drive unit.

11. The mobile drive unit of claim 6, wherein the instructions instruct the mobile drive unit to disengage the inventory holder and re-engage the inventory holder at a different position for docking based on the information obtained by the sensor.

12. The mobile drive unit of claim 6, wherein the instructions instruct the mobile drive unit to retain the inventory holder in a docked state based on the information obtained by the sensor.

13. The mobile drive unit of claim 6, wherein the instructions instruct the mobile drive unit to move abruptly so as to move at least one inventory item stored by the inventory holder.

14. The mobile drive unit of claim 6, wherein the instructions instruct the mobile drive unit to vary a speed of travel of the mobile drive unit based on the information obtained by the sensor.

15. The mobile drive unit of claim 6, wherein the instructions instruct the mobile drive unit to alter a destination based on the information obtained by the sensor.

16. The mobile drive unit of claim 6, wherein the module is further configured to at least one of receive or generate information for:

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

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

17. A mobile drive unit comprising:

a propulsion system configured to move the mobile drive unit between locations of a workspace;

a docking assembly configured to couple with a frame of an inventory holder for movement of the inventory holder between locations of the workspace by the propulsion system of the mobile drive unit; and

a first magnetic element connected to the docking assembly and comprising one of a ferromagnetic surface or one or more magnets, the first magnetic element configured to magnetically couple with a second magnetic element that (i) is connected to the frame of the inventory holder and (ii) comprises another of the ferromagnetic surface or the one or more magnets, the first magnetic element configured to magnetically couple with the second magnetic element 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 mobile drive unit 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 mobile drive unit of claim 17, wherein said one or more magnets comprise one or more electromagnets configured to, when activated, magnetically couple the inventory holder to the mobile drive unit.

20. The mobile drive unit 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.