About 20 workers at the Amazon fulfillment center in this suburb southwest of Minneapolis gathered around a supervisor early one morning before starting another shift. Yelling above all the commotion of a 855,

The robot revolution has long sounded like a far-off sci-fi notion, but it’s a reality at the e-commerce giant.

Hercules, a lifter capable of handling 1,250 pounds; Pegasus, which sorts packages on conveyor belts; and Proteus, the company's first fully autonomous robot able to operate directly alongside people.