Dual Stage Control for Field Printer Robot

This paper presents a novel method for controller design for a dual input single output (DISO) system with application to a robot for printing layouts at construction sites. The differential drive robot has a separately controlled linear actuator that moves the print head perpendicularly to the fore-aft axis of the robot. The output is the lateral position of the print head; the sum of the position of the linear actuator (faster stage) relative to a reference point on the front of the robot, which is determined by the steering of the robot (slower stage). Both are measurable. The controller coordinates the action of the separately controlled linear actuator and the differential steering to achieve fast convergence and sub-millimeter tracking. Simulations and experimental results demonstrate the effectiveness of the approach.