BOT payload alignment and sensing

1. An autonomous transport robot for transporting a payload comprising:

a payload bed having a payload port surface and at least one movable pose defining reference datum surface; and

at least one payload justification device;

wherein 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 pose defining reference datum surface that is arranged relative to the payload support surface to place each payload so that a payload side is at a repeatable predetermined longitudinal position, independent of a payload size, on the payload bed relative to at least a longitudinal axis of the autonomous transport robot.

2. The autonomous transport robot of claim 1 , wherein the at least one pose defining reference datum surface includes a first and second reference datum surfaces disposed substantially perpendicular to one another and one of the first and second reference datum surfaces is substantially parallel with the longitudinal axis of the autonomous transport robot.

3. The autonomous transport robot of claim 1 , wherein the autonomous transport robot includes a retaining fence disposed at an opening of the payload bed, the autonomous transport robot further including a driven pusher bar movably disposed at least partly above the payload bed, the retaining fence and the driven pusher bar being configured to actively grip the payload during transport of the payload on the autonomous transport robot.

4. The autonomous transport robot of claim 1 , wherein the autonomous transport robot further comprises at least one sensor for detecting at least one dimension of the payload.

5. The autonomous transport robot of claim 1 , wherein the autonomous transport robot further includes a retractable effector for transferring the payload between a payload holding area and the payload bed, the payload bed including guide surfaces configured to guide the payload into an area of the payload bed during transfer of the payload onto the autonomous transport robot.

6. The autonomous transport robot of claim 5 , wherein the effector is configured to be raised from below the payload bed to a position at least partially above a retaining fence disposed at an opening of the payload bed, the retaining fence extending above the payload bed and being configured to at least in part retain the payload on the payload bed.

7. The autonomous transport robot of claim 1 , wherein the at least one justification device includes a first justification device configured to move the payload in a first direction to substantially contact the first reference datum surface and a second justification device configured to move the payload in a second direction, substantially perpendicular to the first direction, to contact a second reference datum surface.

8. The autonomous transport robot of claim 1 , wherein the first justification device includes driven rollers that form a payload support surface of the payload bed.

9. The autonomous transport robot of claim 1 , wherein the second justification device includes a driven pusher bar.

10. The autonomous transport robot of claim 1 , wherein the autonomous transport robot includes at least one sensor for detecting the substantial contact between the payload and at least one of the first and second reference datum surfaces.

11. The autonomous transport robot of claim 1 , wherein the first justification device is configured to move the payload a predetermined distance away from a respective one of the pose defining reference datum surfaces when the payload is transferred off of the payload bed and the second justification device is configured to re-justify the payload against the second reference datum surface.