The angles of departure and approach of the root-loci in linear multivariable systems

Abstract

Expressions are derived for the angles of departure of the root-loci from the open-loop system poles of linear multivariable systems and the angles of approach to the finite zeros of such systems. The concept of the finite zeros attractivity is introduced and its relation to the behaviour of the loci at intermediate gain values is discussed. The angles of approach of the loci that tend to the finite zeros ore also related to the angles of departure of the corresponding loci from the poles of the inverse system.