Design and implementation of a general tracking controller for Friction Stir Welding processes

This paper establishes a method for force filtering, develops a dynamic process model, and designs and implements a general tracking controller to regulate the axial force for a variety of reference signals in friction stir welding processes. Steady state and dynamic models are used to relate the input process parameters to the axial force. The general tracking controller is implemented in a Smith predictor-corrector structure to compensate for a pure communication delay. The controller successfully performs bead-on-plate welds using a 6061 aluminum alloy. Both constant and sinusoidal reference forces are tracked.