ABSTRACT The Letov formula allows the computation of closed‐loop poles in the classical linear quadratic regulator context. In this paper, a similar formula is proposed to compute, directly from the transfer function of a bounded real system, the closed‐loop poles of the system under a suitable performance index. Moreover, the presented result allows both to directly verify whether an asymptotically stable system is BR and, if not, to compute its norm.
Fortuna et al. (Fri,) studied this question.