# Identification of control system type? Open loop or close loop,

What is the type of control system of door closer in attached photo?

• If I put that picture and question together on a test, it would be an essay question, I'd ask the student to justify their conclusion, and I'd be using the justifications to assess the student's understanding of what a control loop is. Bet me \$20 that it's one, and I'll give you a convincing argument why it's the other. – TimWescott Sep 5 '19 at 0:26

This a spring loaded dampening system that one can describe in a form of $$\ddot{x} + 2 D \omega_{0} \dot{x} + \omega_{0}^2= 0$$

It's simply a piston and spring with a mechanical leverage system that pulls the door closed, since it will try to return to it's most stable position, This is stable open loop system with poles certainly on the left half plane.

Here is an example of a norton 1600, but a google image search will turn up all sorts of different implementations

There is no external force beyond one opening the door, no electronics, sensors or electricity and no controlforce.

As far as I understand, the device is not measuring anything. I think the door closer is an open-loop system that either always applies pressure on the door or applies more pressure on the door as you open the door and the natural steady-state position is door-closed position. neither of these systems doesn't use any measuring device to get feedback of the output.