Various terms are used for this product - try them all!
Or, follow up on a brand name or company name, i.e. iRobot's Packbot
Expenditures - Estimated total funding for unmanned systems of the U.S. Department of Defense from FY 2014 to 2018, by branch (in million U.S. dollars.) See "Ground" data.
Below: recent articles in the Business Source Premier database - from trade publications - on the topic "automated guided vehicle systems." These provide news on competitors and market conditions. You can further limit the search in the side bar, or change keywords. If you need more of the same, you could also try ABI/INFORM or LexisNexis.