Mobile drive unit charging

Patent metadata

Field	Value
Publication number	US-9663296-B1
Application number	US-201615159917-A
Country	US
Kind code	B1
Filing date	May 20, 2016
Priority date	Sep 25, 2013
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

Some examples include charging an onboard power source of a mobile drive unit (MDU) of an inventory system while the MDU is operating in the inventory system, rather than removing the MDU from service for recharging. As an example, the MDU may receive instructions to retrieve an inventory holder, and an onboard power source of the MDU may be charged while the MDU and the inventory holder are located at the charging station.

First claim

What is claimed is:

1. A mobile drive unit (MDU) comprising:
one or more onboard power sources;
a communication module to receive instructions, from a management module of an inventory system, to retrieve an inventory holder from a particular location in the inventory system;
a drive module to propel the MDU to at least the particular location of the inventory system using power from the one or more onboard power sources; and
a charging interface to couple at least one of the one or more onboard power sources to a charging station associated with an inventory station to charge the one or more onboard power sources while (i) the MDU and the inventory holder are located at the inventory station and (ii) the MDU is expected to remain stationary for an amount of time associated with completion of a task associated with the inventory holder or the MDU.

2. The MDU of claim 1 , further comprising:
a first onboard power source of the one or more onboard power sources comprising a fast charging power source; and
a second onboard power source of the one or more onboard power sources comprising a slow charging power source;
wherein the charging station charges the first onboard power source; and
wherein the first onboard power source charges the second onboard power source.

3. The system of claim 2 , wherein the task associated with the MDU comprises charging only the first onboard power source.

4. The MDU as recited in claim 2 , wherein the first onboard power source comprises a capacitor; and
wherein the second onboard power source comprises a lead-acid battery.

5. The MDU as recited in claim 1 , further comprising:
one or more induction components,
wherein the one or more onboard power sources is coupled to the charging station via the one or more induction components to an induction coupling component associated with the charging station.

6. The MDU as recited in claim 1 , further comprising:
one or more wireless charging components,
wherein the one or more onboard power sources is coupled to the charging station via the one or more wireless charging components to a wireless charging connection associated with the charging station.

7. A method comprising:
determining a charge level for each onboard power source of a plurality of mobile drive units (MDUs);
determining a dwell time associated with a first task to be performed with respect to an inventory holder or an MDU of the plurality of MDUs;
selecting an MDU of the plurality of MDUs to perform the first task based at least in part on the charge level of the onboard power source of the MDU and the dwell time associated with completing the first task; and
charging the onboard power source of the MDU while the first task is being performed.

8. The method of claim 7 , further comprising:
directing the MDU to move to a first location associated with the inventory holder;
directing the MDU to move the inventory holder from the first location to a second location, the second location comprising an inventory station, the inventory station comprising a charging station; and
charging the onboard power source of the MDU while the MDU and the inventory holder are located at the charging station and the first task is being performed.

9. The method of claim 7 , wherein charging the onboard power source of the MDU comprises charging a fast charging power source of the onboard power source, the method further comprising:
charging a slow charging power source with the fast charging power source after the MDU has left a charging station.

10. The method as recited in claim 7 , further comprising coupling the onboard power source to a charging station via an induction coupling component.

11. The method as recited in claim 7 , further comprising coupling the onboard power source to a charging station via a wireless coupling component.

12. The method of claim 7 , wherein charging the onboard power source of the MDU further comprises:
charging a fast charging power source of the onboard power source at a first charge rate; and
charging a slow charging power source of the onboard power source at a second charge rate;
wherein the first charge rate is greater than the second charge rate.

13. The method of claim 7 , wherein determining a charge level for each onboard power source of the plurality of MDUs comprises:
determining the charge level of a fast charging power source of the onboard power source; and
determining the charge level of a slow charging power source of the onboard power source;
wherein selecting an MDU of the plurality of MDUs to perform the first task is based at least in part on the respective charge levels of the fast charging power source and the slow charging power source of the MDU.

14. A method comprising:
determining a charge level of each onboard power source of a plurality of mobile drive units (MDUs);
determining a dwell time associated with a first task to be performed with respect to a first inventory holder;
determining a dwell time associated with a second task to be performed with respect to a second inventory holder;
selecting a first MDU of the plurality of MDUs to retrieve the first inventory holder based at least in part on the charge level of the onboard power source of the first MDU and the dwell time associated with completing the first task;
selecting a second MDU of the plurality of MDUs to retrieve the second inventory holder based at least in part on the charge level of the onboard power source of the second MDU and the dwell time associated with completing the second task;
charging the onboard power source of the first MDU while the first task is being performed; and
charging the onboard power source of the second MDU while the second task is being performed.

15. The method of claim 14 , wherein the dwell time associated with the first task is longer than the dwell time associated with the second task; and
wherein the charge level of the onboard power source of the first MDU is lower than the charge level of the onboard power source of the second MDU.

16. The method of claim 14 , further comprising:
directing the first MDU to move to a first location associated with the first inventory holder; and
directing the first MDU to move the first inventory holder from the first location to a second location, the second location comprising a first inventory station, the first inventory station comprising a charging station.

17. The method of claim 16 , further comprising:
directing the second MDU to move to a third location associated with the second inventory holder; and
directing the second MDU to move the second inventory holder from the third location to a fourth location, the fourth location comprising a second inventory station, the second inventory station comprising a charging station.

18. The method of claim 14 , wherein each onboard power source comprises:
a first power source comprising a fast charging power source; and
a second power source comprising a slow charging power source;
wherein selecting the first MDU to retrieve the first inventory holder is based at least in part on the respective charge levels of the fast charging power source of the first MDU and the slow charging power source of the first MDU.

19. The method of claim 18 , wherein the dwell time associated with the first task is shorter than the dwell time associated with the second task; and
wherein the charge level of the slow charging power source of the first MDU is higher than the charge level of the slow charging power source of

Assignees

• Amazon Tech Inc

Inventors

• Dingle Patrick Ryan
• Verminski Matthew David
• Mansfield Peter K
• Stubbs Andrew
• Breheny Sean Hugh
• Wurman Peter R

Classifications

• H02J2105/30

  the load networks being external to vehicles, i.e. exchanging power with vehicles · CPC title

• H02J7/82

  Control of state of charge [SOC] · CPC title

• H02J7/50

  acting upon multiple batteries simultaneously or sequentially · CPC title

• B60L53/32

  by charging in short intervals along the itinerary, e.g. during short stops · CPC title

• B60L11/1837

  Operations & Transport · mapped topic