FAQ: How is 'open loop' a feedback mechanism?
Date: 27 Sep 04
Answered by: Kevin Tang
When we say "open loop", that means there is no feedback. I guess you are confused by the figure 1.1 in chapter 1. Authors really want to show you the most general form of a control system there. It can be a feedback control system, like the one shown in subfigure (a), or a non-feedback control system, like the one shown in subfigure (b), an open loop, where you can only use system 1 to control system 2 but not vice versa. A little bit side knowledge here. As you will learn later, when you try to design or analysize a closed loop system, the corresponding open loop system is very likely to be the target to study first.