An order-picking method, carried out in an order fulfillment facility using a plurality of mobile robotic units operated autonomously or semi-autonomously in the order fulfilment facility used to fulfill orders placed by individuals on-line or from a catalogue or to fulfill orders placed by a retail establishment of full or split cases that are bound for individual stores of a chain of retail establishments, said method comprising: autonomously routing a plurality of mobile robotic units (14, 114, 214) in an order fulfillment facility, wherein said autonomous mobile robotic units (14, 114, 214) include an autonomous vehicle base, wherein said autonomous vehicle base is capable of self-navigation from any starting point in fulfillment facility to any utilization point without special infrastructure and autonomous vehicle base is capable of sensing humans and unanticipated obstructions and modifying its path plan to avoid the human/obstruction without any further intervention; and picking articles to or putting articles from said robotic units in said order fulfillment facility, wherein at least one of said autonomous mobile robotic units includes a robotic arm and including picking articles or putting articles with said robotic arm; wherein said picking articles or putting articles includes picking articles to or putting articles with said robotic arm from another of said autonomous mobile robotic units, wherein said robotic units are adapted to alter planned path of movement in order to function in the presence of the persons, wherein said robotic units (14, 114, 214) and the persons can function together in said order fulfillment facility, wherein said picking articles to or putting articles from said robotic units includes manually picking product to or putting product from pick stations in said facility. autonomously routing a plurality of mobile robotic units (14, 114, 214) in an order fulfillment facility, wherein said autonomous mobile robotic units (14, 114, 214) include an autonomous vehicle base, wherein said autonomous vehicle base is capable of self-navigation from any starting point in fulfillment facility to any utilization point without special infrastructure and autonomous vehicle base is capable of sensing humans and unanticipated obstructions and modifying its path plan to avoid the human/obstruction without any further intervention; and picking articles to or putting articles from said robotic units in said order fulfillment facility, wherein at least one of said autonomous mobile robotic units includes a robotic arm and including picking articles or putting articles with said robotic arm; wherein said picking articles or putting articles includes picking articles to or putting articles with said robotic arm from another of said autonomous mobile robotic units, wherein said robotic units are adapted to alter planned path of movement in order to function in the presence of the persons, wherein said robotic units (14, 114, 214) and the persons can function together in said order fulfillment facility, wherein said picking articles to or putting articles from said robotic units includes manually picking product to or putting product from pick stations in said facility.