An inventory system includes a plurality of mobile drive units with a processor control and with a positioning system that enables the mobile drive units to navigate a factory floor. The mobile drive units interface with a material handling system to receive order requests and deliver inventory items...http://www.google.com.tw/patents/US20040010337?utm_source=gb-gplus-share專利 US20040010337 - Material handling method using autonomous mobile drive units and movable inventory trays
