Computer-aided implementation of graphical root locus design recipes

Root locus design is an inherently iterative process by which the poles and zeros of a system are selected to provide a desirable time response. However, trial and error can be greatly reduced using graphical design recipes. With the advent of computer-aided design (CAD) tools, most of the graphical recipes lost their appeal. The authors provide procedures for the computer implementation of graphical s-domain design recipes. The procedures can be implemented using any computer-aided design package. They discuss lead, lag, lag-lead, PI, PD and PID control. Examples are provided.