Two-Degree-of-Freedom Spatial Robust Preview Repetitive Control for Rotational Systems

This article presents a two-degree-of-freedom (2DOF) spatial robust preview repetitive control (2DOF-SRPRC) method for a rotational system that ensures robust tracking and disturbance rejection for spatial periodic signals. After explaining the method of building a model in the spatial domain, we present the configuration of a 2DOF-SRPRC system that contains two loops: A loop focuses on exact feedback linearization and the other loop deals with repetitive control issues in the spatial domain. The spatial repetitive control loop has a 2DOF structure that has a feedback controller and a feedforward controller. A repetitive controller contained in this loop ensures the steady-state high-precision reference tracking and disturbance rejection for spatial periodic signals. The feedback controller is designed by optimizing the sensitivity of the system to ensure system robustness against model uncertainties. The feedforward controller is designed to achieve ripple-free deadbeat tracking control. The experimental results of a mechatronic control system demonstrate the validity of the method.