2023 Volume 59 Issue 5 Pages 243-251
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.