Scalability of feedback control systems for plug-and-play control

In this paper, with the help of the Youla parameterization, the realizations of feedback control systems are discussed which results in a preferable and more convenient way to realize plug-and-play (PnP) control without modifying pre-designed control systems. Furthermore, based on the equivalence of different realizations of the Youla parameterization, a link between the standard feedback and the observer-based state feedback control system is given so that the well developed observer-based control techniques, like LQG/H₂ control etc., can be achieved in the standard feedback control system via PnP control design. The effectiveness of the proposed PnP design schemes is verified using a direct current (DC) motor benchmark system.