VIRTUAL REFERENCE FEEDBACK TUNING IN RESTRICTED COMPLEXITY CONTROLLER DESIGN OF NON-MINIMUM PHASE SYSTEMS

Abstract This paper discusses the applicability of the identification-based Virtual Reference Feedback Tuning scheme in (Campi et al. , 2002; Campi et al. , 2003; Sala and Esparza, 2005) to reduced-order controller design. As the presence of zeros outside the unit circle is quite usual in sampled-data systems, a particular discussion on the topic is carried out. Also, reduced-order controllers identified with the VRFT scheme may not meet the specifications (or even be unstable) so some invalidation tests are needed prior to experiment.