Simple Controller Design to Achieve Iso-Damping Robustness: Noniterative Data-Driven Approach Based on Fractional-Order Reference Model

This study proposes a simple controller design approach to achieve a class of robustness, the so-called iso-damping property. The proposed approach can be executed using only one-shot input/output data. An accurate mathematical model of a controlled plant is not required. The model-reference (MR) control problem is defined to achieve the desired closed-loop specifications, including the iso-damping, and the reference model is designed on the basis of FC. The optimization problem for the MR control is formulated using the one-shot input/output data while considering the bounded-input–bounded-output (BIBO) stability from a bounded reference input to a bounded output. The iso-damping robust controller is obtained by solving the optimization problem. The representative advantages of the proposed approach over the conventional methods are the simplicity, practicality, and reliability from the viewpoint of the unnecessity of the plant model and explicit consideration of the BIBO stability from a bounded reference input to a bounded output. Numerical and experimental studies demonstrate the validity of the proposed approach.