Tracking Control and Reference Trajectory Generation in a LOM System

An improvement in contour accuracy is acquired by the introduction of a tracking controller and a trajectory generation policy in a laminated object manufacture (LOM) system. A model of the positioning system is developed as the design basis of the tracking controller. A zero phase error tracking controller (ZPETC) is used to eliminate single axis following error, and thus reduce the contour error. Then the cross-coupled controller (CCC) is introduced to further minimise the contour error caused by the two-axis mismatch; the method of off-line generating of two-dimension reference trajectories followed by the positioning system is proposed. Simulation is developed using a Matlab model and satisfactory results are obtained.