Model Free ESO-Based Repetitive Control for Rejecting Periodic and Aperiodic Disturbances

This paper presents an extended state observer (ESO) based repetitive control (RC) to compensate periodic signals, aperiodic disturbances, and uncertainties of the plant with relative degree equal to or greater than zero. Since linear ESO has only two tuning parameters, the proposed controller provides a simple and user friendly solution to complex engineering problems in practice. Moreover, due to the model free approach of a ESO-based control, it can be applied to a wide variety of plants. The design procedures are proposed to ensure a stable system. Various types of disturbances are used in simulations and experiments which show that the ESO-based RC cannot only reject periodic and aperiodic disturbances but also handle the plant parameter uncertainty. The comparison studies demonstrate that the ESO-based RC has superb performance.