Response of the Open-loop and Closed-loop System

Figure 23.3: Response of the open and closed loop systems

Note the following point:

The open-loop response shows oscillation around 2 with a light damping while the closed-loop response shows damping of vibration within 10 seconds and the system following the step input.

Now you vary the compensator as
(a)
(b)
and compare the closed loop response of the system

You will find with zero K_I , the vibration is continuing for a longer time and with zero K_D , the system will take more time initially to pick up with the reference value.

To understand this better you are advised to go through quickly through the basics of classical control in the subsequent slides. If you are familiar with this concept then you can directly go to slide 9 of this lecture.