Data-driven Estimation and Update Rule of Circle Parameters in Nyquist Plots Characterizing a Class of Stabilizing Controllers

Abstract

In this paper, we propose a data-driven estimation method of multiple circle parameters which characterize a class of stabilizing controllers in Nyquist plots in a situation where a plant model is unknown. In the previous work, we derived the class of stabilizing controllers with an estimated circle. However, if we can estimate multiple circle parameters, we obtain multiple classes of stabilizing controllers. Therefore, we estimate multiple circle parameters and propose efficient update rules for data-driven methods.