A method for the determination of s-plane realizability regions

A method for the determination of boundary lines that enclose the root contours of control systems is presented. The boundary lines divide the
s
plane into realizability regions within which the complex conjugate roots of the system characteristic equation must lie. The method is valid for positive and negative real values of two variable system parameters. Furthermore, the implementation of this method does not require the need for the tedious construction of individual root loci as is usually the case. Examples of the determination of realizability regions of a multivariable and multiloop feedback control systems are presented.