A Note on the Youla-Bongiorno-Lu Condition

Abstract

Youla, Bongiorno and Lu have presented a condition for the stabilizability using stable controllers of an unstable plant. We show this condition may be reformulated in terms of Cauchy indices, allowing its checking in a finite number of rational operations, should the plant not be given in factored form, i.e. should its poles and zeros be unknown. The results applies to discrete and continuous-time, and scalar and multivariable plants. Show more