ABSTRACT
This chapter discusses the notion of root locus design. It explains the procedure of creating root loci and outlines their uses. Root locus is a powerful graphic method used in the analysis and design of control systems. Feedback control system and the root locus illustrates how the poles of the closed-loop system vary with system parameters in particular the closed-loop gain. Time delays often arise in control systems, both from delays in the process itself and from delays in the processing of sensed signals. Real control systems are inherently nonlinear, and the linear analysis and design methods that have been described so far use linear approximations to the real models. In order to use the root locus as a design tool and to verify computer-generated loci, it is very important to be able to sketch root loci.
