1. The Excitement of Control Engineering
Once sensors are in place to report on the state of a process, then the next issue is the ability to affect or actuate the system, in order to move the process from the current state to a desired state. Thus, we see that actuation is another intrinsic element in control problems. The availability of new or improved actuators also often opens the door to significant improvements in performance. Conversely, inadequate or poor actuators often lie at the heart of control difficulties. A typical industrial control problem will usually involve many different actuators--see, for example, the flatness control set-up shown in Figure 1.3.