Abstract: An autonomous transport robot for transporting a payload, the autonomous transport robot includes a payload bed having at least one reference datum surface and at least one payload justification device, the at least one payload justification device being configured to position a payload on the payload bed in substantial contact with the at least one reference datum surface to place the payload in a predetermined position on the payload bed.

Abstract: An autonomous transport vehicle for transporting items in a storage and retrieval system is provided. The autonomous transport vehicle includes at least two drive wheels and a controller, where each drive wheel is independently driven and a drive wheel encoder is disposed adjacent each drive wheel. The controller, in communication with the drive wheel encoders, is configured to determine a kinematic state of the autonomous transport vehicle within the storage and retrieval system based on incremental data from the drive wheel encoders only and independent of drive wheel slippage.