Over one Century of Spectrum Analysis in Delay Systems: An Overview and New Trends in Pole Placement Methods

Pole placement represents a classical method for controlling finite-dimensional linear time-invariant systems, largely covered in the open literature. Basically, it consists of placing poles closed-loop system some predetermined loci complex plane. This paper discusses extensions this to systems described by delay-differential equations. Among others, finite spectrum assignment (FSA), continuous pole (CPP) and partial (PPP) approaches are presented illustrated through simple low-order dynamical systems.