program block diagram in matlab, not simulink

Hi,

I have an task to calculate the transferfunction with an given, complicated block diagram. So I simplify the block diagram until I have the complete transfer function in the last block - not a problem. Now I have the next task which tells me to proof that my previous calculations are correct using matlab (not simulink, which would be the third task; and I have already done that to make sure my transfer function from task a) was correct)

So my question is: how do I translate a block diagram with given transfer functions into matlab code? I can easily define all the blocks' transfer functions like G1=tf(c1,d1);, but how do I tell matlab in code where a sum is, where a branch splits etc?

I would realy appreciate any help, as that is something our professor does not show in his vids and leaves to our own to figure out -.-

Thank you very much,

Dennis

Answer 1

[Paul]

Look at

doc connect

and see if that helps.

[Dennis Gardiner]

Looks very complicated in comparison to just using simulink, but I think that will work, I will definitely give it a try.

If it works I will accept the answer soon.

Thanks for the fast answer.

[Dennis Gardiner]

Hi Paul,

though I dont fully understand what the output means be first time looking at it for two seconds, just throwing a tf() over the output of the connect-command gave me my correct transfer function.

Thank you very much!

[Paul]

Feel free to ask any follow-up questions if something is still unclear after you've read the doc page(s).

Also, an alternaltive approach is to use the interconnection commands, like

doc series
doc parallel
doc feedback

You can use the these commands to implement what you probably already did by hand.

You can also use LTI system algebra, though that's not recommended.

Check this link for examples of these methods.

[AMUTHA]

doc series