ABSTRACT
There are several advantages to the use of feedback in control systems, as illustrated by the example of a velocity servo in Chapter 1. However, there are also potential problems with feedback systems that must be mitigated in their design. Perhaps the most important of these is the natural tendency of systems with feedback to oscillate, just like any other vibrating system. The unique problem with feedback systems is that the magnitude of their oscillations can increase without bound if they are not properly designed. We will first take a brief detour into the realm of vibrating systems and see in some detail how they are analyzed mathematically. Then, we will relate the analysis technique to closed-loop feedback systems.
