A position domain iteration learning control for contour tracking with application to a multi-axis motion testbed

To improve contour tracking performance for multi-axis precision motion systems, a position domain iteration learning control (PDILC) is presented in this paper. Traditional control approaches design controllers in time domain individually, thus suffer from poor synchronization of relevant motion axes and result in restriction for contour tracking tasks. Our approach is to combine the positon domain method with the ILC to reduce the contour errors and individual axis simultaneously for repetitive tasks. Stability and convergence analysis of the proposed method are conducted through lifted system representation method. Performance of the PDILC, traditional time domain ILC (TDILC) and feedback control lonely are evaluated and compared through numerical simulations and experimental testing based on a multi-axis precise positioning stage. The proposed method enhances the precision contour tracking performance of the testbed.