Module 4 : Feedback controller

Lecture 6 : Stability of a closed loop process

Fig. IV.10: Root Locus diagram


The Fig. IV.10 demonstrates the root locus diagram of the said example. The loci of the complex pair of poles cross the imaginary axis at


Let us take a second example where transfer function of a process is

(IV.46)

The characteristic equation is

(IV.47)

The following table shows the values of roots of the characteristic equation as changes from 0 to .