Open-Loop vs. Closed-Loop Transfer Function (What's the difference and when to use them)

In this video, I go over the meaning of Open-Loop and Closed-Loop Transfer functions as they apply to control systems. This is basically a conceptual overview of classical feedback control, and shows some important connections between tools used in control systems. Please note that the example root locus diagram is for an OLTF without any zeros.
Timestamps:
00:00 - Introduction
00:39 - Block diagram and closed-loop transfer function
02:21 - Characteristic equation and open-loop transfer function
03:25 - Root locus diagram
05:48 - Rewriting characteristic equation for marginally stable poles
07:54 - Bode plots
12:00 - Review with PowerPoint
15:15 - Summary
If you have any questions or want to see me make a video about something, please leave a comment below!
Errata:
In my PowerPoint I wrote,"Systems are characterize by their poles"
This should be "Systems are characterized by their poles "

[@arsalansyed4709]

thanks dude! This was super helpful!

[@SkeleCrafteronYT]

Best video on yt, best summary of control systems

[@dmdengineering]

Thank you! I think this concept confuses a lot of people, and I am glad I can help

[@cassandrathompson8969]

This was so helpful, thank you!

[@borisgindlin4156]

Nicely done! It would help to expand on the RL and BP general connection, there is a lot of magic there still!

[@adrianwong69]

Thank you! You help me on my assignment

[@harrisonelliott8305]

Great vid!

[@isacdaimary9908]

Thank you so much

[@thevitruvianman9781]

Thanks DMD

[@alexandertanghe8562]

Hi, Nice video! I've a problem related to this topic that I can't seem to figure out. Could you maybe help me?

[@K0ldsoul]

Does DMD refer to dynamic mode decomposition by any chance? nice video btw.

[@dmdengineering]

Nope. Just my initials. Thanks!

[@adityathakur3748]

Hey bro I am not able to understand how closed loop stability is related to open loop transfer function what are the conditions of open loop transfer function to make CLTF stable .

[@shrinivasiyengar5799]

There are no explicit conditions other than your closed-loop poles need to be in the left half plane (on in the unit circle in discrete systems). As he said, take your open loop system (G*H) and plot the root locus to see what value of gains k could make your system stable.

[@tehpeng69]

nice nails brother

[@baradenreddi3508]

bro where is the how to draw a root locus video??

[@dmdengineering]

Not sure if you still need this, but I just uploaded one on my channel (kzbin.info/www/bejne/rJTOgaeOedd4qdk)

[@Time4yes]

How can I apply this to solve plant instabilities that uses PLCs?

[@dmdengineering]

That is a good question, but well beyond the level of this video. From a basic level, you can model your plant as a linear system and then use the classical control methods discussed here to design a linear controller to bring the unstable poles back to the left half plane. Unfortunately implementation on PLCs isn't something I have much experience with, so you'll have to look elsewhere to find how to do that. Good luck!

[@Time4yes]

@@dmdengineering thank you so much.