Feedback Control

In Chap. 1, we have mentioned that closed-loop feedback control systems play a much more important role than open-loop control systems in control science and engineering. We have also presented a variety of representative examples of closed-loop feedback control systems. Questions arise naturally: why cannot we simply use open-loop control systems? Why is feedback control so important to control systems? What are basic utilities of feedback control? In this chapter, we gradually clarify answers to these questions.