Feedback-based iterative learning controller design using the robust performance condition of uncertain feedback control systems

Generally, an iterative learning controller is added on the existing feedback control system to improve the tracking performance. However, the iterative learning controller has been designed without utilizing effective information used in the de sign of the feedback controller. This paper proposes a robust convergence condition in the L₂ -norm sense for an iterative learning control (ILC) system including a feedback controller and an uncertain linear time-invariant plant. We present a method to design an iterative learning controller using the information on the performance of the existing feedback control system. From the obtained results, several design criteria for the ILC system are provided.