ROBUST NEAR-TIME-OPTIMAL COMMAND SHAPING FOR COORDINATED CONTOUR CONTROL

Contour tracking is of great importance in many applications where contouring error is the minimization objective. In contrast to traditional, uncoordinated contour control where tracking error in each axis is controlled independently, coordinated contour control directly addresses the contouring error and therefore is more effective in rejecting disturbances or modeling errors. This paper proposes a feedforward strategy that increases contouring speed. A combined state-space system is first formed containing the model of each axis, and contouring error is expressed in terms of the states. Then the robust near-time-optimal command shaping technique is applied. A non-robust design and a 1st-order robust design are compared. And a strategy is proposed to eliminate undesirable reversals that may occur in the robust design.