US Patent 8649899 System and method for maneuvering a mobile drive unit

A method of rotating an inventory holder includes moving an inventory holder towards a rotation area along a straight segment of a path with a first face of the inventory holder facing a first direction. The rotation area includes a portion of a workspace designated for rotation of inventory holders. The method further includes moving the inventory holder into the rotation area along a first arced segment with an orientation of the first face perpendicular to the first arced segment. The method additionally includes executing a rotation maneuver within the rotation area and moving the inventory holder out of the rotation area along a second arced segment with a second face facing the first direction.