Robots -- they scan our groceries, build our cars, aggregate our news, direct us to the quickest route home, they even serve us cupcakes! This week we set out to discover just how ubiquitous robots are, and to what extent they govern our lives.  Marketplace’s David Brancaccio embarked on a 3,200-mile transamerican odyssey with his robot dog Wilson and a microwave oven. His mission: cross the country without interacting with another human being. We hear excerpts from his road diary and what it's like to live in a world where your only companions are machines.