On the singularity and discontinuity of indirect adaptive YJB-based control structure: The ideal case

The singularity and discontinuity problems for applying the YJB parametric control structure to indirect adaptive control systems under the ideal case are addressed. To avoid the inherent singularity and discontinuity problems, modified estimated parameters via a hysteresis modification procedure are used to construct the YJB-based adaptive controller. It is shown that global stability is attained even when the plant has poles or zeros on the unit circle