Re: rlocus

[Andrei]

Eduardo Adam wrote:

> Thanks Andrei, your suggestion works very well, however, the following mesage 
> is written
>
> octave:2> [ro,k_breaks,roots,gains,x_breaks]=rlocus(tf(n,d),0.1,0,10);
> warning: in /usr/share/octave/2.1.73/m/control/base/rlocus.m near line 2, 
> column 35:
> warning: rlocus: some elements in list of return values are undefined
>
>  
Try to install Octave 2.9.12

> Anyway, I have what I'm looking for, that is, the roots related to the gain.
> One more question, please,
> Is there any control toolbox manual in the web?  Because, your suggestion with 
> rlocus comand doesn't appear in the trational help.
>
>  
Yes, you can go to http://octave.sourceforge.net/
and have the documentation: http://octave.sourceforge.net/doc/index.html

If you want, I developed a function, having a specific zeta, obtain the 
gain and the roots(pirlocus).
http://mexinetica.com/~audreiev/archivos/dev/octave/

> Thanks.
> Eduardo.
>
>
>
>  
>
> > In that case, you should specify the returning parameters:
> > [ro,k_breaks,roots,gains,x_breaks]=rlocus(tf(n,d),0.1,0,10)
> > and you will get all the roots of the system in variable "roots", with
> > their respective gains in vector "gains".
> > i.e.
> > roots(:,1)     are from    gain(1)
> >
> > Eduardo Adam wrote:
> >    
> >
> > > On Thursday 21 June 2007 14:04, Andrei wrote:
> > >
> > > Andrei
> > >
> > >      
> > >
> > > > ro in your case is the graph, that is plotted.
> > > > the rlocus function returns multiple roots of the system and graph with
> > > > different gain (K),
> > > >        
> > > This is exactly what I want.  That is, multiple roots for different gain
> > > (K) and the comand,
> > > [ro,Kr]=rlocus(tf(n,d),0.1,0,10)
> > >
> > > it doesn't work on my Kubuntu.
> > >
> > >      
> > >
> > > > if you want a specific root, you should use the feedback function for a
> > > > closed loop, convert the system form to a transfer function and get the
> > > > roots of the denominator:
> > > > octave:1> n=1; d=[1 3 2 0];
> > > > octave:2>[num,den]=feedback(tf(n,d),tf(1,1));
> > > > octave:3>roots(den)
> > > > ans =
> > > >   -2.32472 + 0.0000i
> > > >   -0.33764 + 0.56228i
> > > >   -0.33764 - 0.56228i
> > > >
> > > > Eduardo Adam wrote:
> > > >        
> > > >
> > > > > Hi everyone,
> > > > >
> > > > > I'm sorry for this basic question but I'm a new octave user and, I'm
> > > > > accustumed to used matlab.  So, I ran the following comands:
> > > > >
> > > > > octave:1> n=1; d=[1 3 2 0];
> > > > > octave:2> [ro,Kr]=rlocus(tf(n,d),0.1,0,10)
> > > > > warning: in /usr/share/octave/2.1.73/m/control/base/rlocus.m near line
> > > > > 3, column 8:
> > > > > warning: rlocus: some elements in list of return values are undefined
> > > > > ro = [](0x0)
> > > > > Kr =
> > > > >
> > > > > -0.38490
> > > > > 0.38490
> > > > >
> > > > >
> > > > > My question is, why I have the answer ro=[]?
> > > > > I'm interested in the closed loop roots and, according to the help,
> > > > > rlocus would have to provide the roots
> > > > >
> > > > > On the other hand, the comand
> > > > > octave:3> rlocus(tf(n,d),0.1,0,10)
> > > > >
> > > > > it works perfectly.
> > > > > My octave version is 2.1.73 and I'm working with linux-kubuntu.
> > > > >
> > > > >
> > > > > Thanks to everyone.
> > > > >
> > > > > Eduardo
> > > > > _______________________________________________
> > > > > Help-octave mailing list
> > > > > address@hidden
> > > > > https://www.cae.wisc.edu/mailman/listinfo/help-octave
> > > > >          
>
>