Abstract
This paper presents a novel design for robust 2-degrees-of-freedom (2-DOF) positioning controller that is robust against frequency perturbations in mechanical vibration modes. The authors have already proposed a coordinate design approach between feedforward (FF) and feedback (FB) controllers for achieving the robust positioning performance. In the conventional design, however, the overshoot and/or undershoot responses at the settling still remained because of variations in the FB control performance in the presence of frequency perturbations, resulting in the deterioration of positioning performance. In this study, therefore, a coordinate design considering the FB control performance is applied to improve the robustness in the positioning performance. The effectiveness of the proposed controller design has been verified by numerical simulations and experiments using a prototype of the galvano scanner.
