Design of a discrete-time terminal sliding mode repetitive controller

This paper proposes a discrete- time terminal sliding mode repetitive controller (TSMRC) for improved robust tracking performance and fast transient response. The proposed control structure integrates the desirable features of repetitive control (RC) and terminal sliding mode control (TSMC) to accomplish a fast convergence rate, improved robustness against bounded matched uncertainties, and improved tracking of periodic reference trajectories. The RC control component aims to improve the tracking of periodic reference signals by eliminating periodic error at steady state. While, the discrete-time TSMC controller is added to improve the robustness of the system and achieve a fast transient response in the presence of matched uncertainties. Furthermore, a small pure phase advance component is added to the proposed control structure to improve the tracking of periodic reference signals with high frequency components. The effectiveness of the proposed discrete-time TSMRC is verified through simulation testing using a linear actuator (LA) plant model. Design details and a verification of the effectiveness of the proposed TSMRC are presented in this paper.