Amazon has added some additional robotic muscle and computer-vision chops to its warehouses ahead of the tide of holiday shopping orders. The retailing giant said Monday it has 10 of these latest fulfillment centers in operation across the U.S., featuring software and mechanical innovations. The total number of Kiva mobile robots, which transport large vertical racks containing inventory, has topped 15,000 across the U.S., Amazon said Monday. The company agreed to buy Kiva Systems in 2012 and has been adding robot platforms to its warehouses to improve efficiency. Amazon also said it had deployed an inventory-moving robotic arm dubbed Robo-Stow, which according to a press photo is an M-2000iA, made by Japan's Fanuc robotics.