FedEx unveiled a two-armed robot called DexR this week that's designed to automate one of the trickiest tasks facing the company's human employees--loading a van with packages. The new robot aims to use artificial intelligence to stack rows of differently sized boxes inside a delivery van as efficiently as possible, attempting to maximize how many will fit. That task is far from easy for a machine. "Packages come in different sizes, shapes, weights, and packaging materials, and they come randomized," says Rebecca Yeung, vice president of operations and advanced technology at FedEx. The robot uses cameras and lidar sensors to perceive the packages and must then plan how to configure the available boxes to make a neat wall, place them snugly without crushing anything, and react appropriately if any packages slip.