ABSTRACT
We know from the study of a second-order servo that critical damping is achieved when the roots of the system characteristic equation are real and equal. Because the critically damped case is the dividing line between an underdamped system and an overdamped system, there is only one critically damped system. Critically damped performance is desirable because it represents the fastest system that will not overshoot. However, getting the two roots to equalize by manipulating the system variables is extremely difficult to achieve in practice. Once manipulated, variables may drift over time, affecting the transient response. There are an infinite number of underdamped and overdamped systems, and within these systems, many combinations of system parameters.
