Singularity-free adaptive pole placement using periodic controllers

A globally convergent adaptive control scheme for a certain class of nonminimum phase systems is presented. The approach is based on a particular periodic pole-placement controller. An ad-hoc parameter estimation correction procedure is used to prevent any possible singularities in the control law computation. Furthermore, a lower bound on the estimated model controllability is ensured. A priori knowledge of the system is reduced to the process order