Two-Degree-of-Freedom Based Cross-Coupled Control for High-Accuracy Tracking Systems

Recent work recognizes that cross-coupled control (CCC) can significantly improve the accuracy of contour tracking in biaxial systems. However, it´s complicated to apply CCC to arbitrary contour because of extra requirements to calculation and switching the cross-coupled gains. In addition, since most of CCC are based on the PID controlled loops of the individual axes, performances are conserved in some sense. In this paper, we propose a structure for arbitrary regular contours by efficiently determining the cross-coupling gains for CCC with the two-degree-of-freedom (2DOF) controlled to the single axes. Furthermore, an approach for stability analysis of the CCC is posed. Experimental results for a two-axial motion system indicate that the proposed structure eliminates the contouring error significantly.