US Patent 7641461 Robotic systems for automated construction

A robotic system may include a movable gantry robot, and a nozzle assembly movably coupled to the overhead beam of the gantry robot. The gantry robot may include an overhead beam extending between, and supported by, at least two side members slidably mounted on a pair of rails. The nozzle assembly may be coupled to the overhead beam of the gantry robot, and may be configured to extrude material through an outlet. The robotic system may further include a position controller configured to control position and movement of the gantry robot and the nozzle assembly.