Automated system for transporting payloads

A storage and retrieval system comprising:

• a plurality of containers;
• a plurality of sub-totes configured to fit within the plurality of containers, the plurality of sub-totes configured to store different stock keeping units (SKUs) of items;
• autonomous robotic vehicles having a propulsion subsystem and configured to transport the plurality of containers;
• a container storage structure having storage locations configured to store the plurality of containers;
• a workstation accessible by the autonomous robotic vehicles, the workstation comprising, at a first time, a first container comprising a first set of one or more sub-totes holding a first set of one or more items and a second container comprising a second set of one or more sub-totes holding a second set of one or more items, and the work station comprising, at a second time after the first time, the first set of one or more sub-totes having been consolidated with the second set of one or more sub-totes in the second container to free the first container of sub-totes.

A method of operating a storage and retrieval system comprising a tote storage structure for storing totes, a workstation and robotic vehicles for transporting totes to and from tote storage structure and to and from the workstation, the method comprising:

• (a) retrieving first and second totes from the tote storage structure by at least one robotic vehicle, and transporting the first and second totes to the workstation, the first tote comprising a first set of items and the second tote comprising a second set of items;
• (b) consolidating the first and second sets of items into the second tote to empty the first tote;
• and
• (c) returning the second tote to the tote storage structure by a robotic vehicle.