Root locus exercises

1. What is root locus method?
2. How do you interpret root locus?
3. How do you find the stability of a root locus?

What is root locus method?

In control theory and stability theory, root locus analysis is a graphical method for examining how the roots of a system change with variation of a certain system parameter, commonly a gain within a feedback system.

How do you interpret root locus?

Interpreting a Root Locus Diagram

If the real components of all poles are negative, then the system is said to be stable for that value of Kc. If the real component of the pole is positive, the system is unstable for that value of Kc, meaning the output signal will diverge from the set point.

How do you find the stability of a root locus?

The root locus procedure should produce a graph of where the poles of the system are for all values of gain K. When any or all of the roots of D are in the unstable region, the system is unstable. When any of the roots are in the marginally stable region, the system is marginally stable (oscillatory).