COLOGNE, Germany — Estonia’s Milrem Robotics, maker of the THeMIS unmanned ground vehicle, has opened an assembly line for its multifunction robots in the Netherlands, the company announced on Thursday. The plant in Born, Netherlands, is run in conjunction with local company VDL Defentec, which specializes in assembling armored vehicles and their electric propulsion. The facility has already produced its first THeMIS unmanned ground vehicle, or UGV, for the Dutch government, part of a run of