On Thu, Apr 19, 2018 at 6:20 AM, Beginner1 <address@hidden> wrote:
Hi!,
I would like to know how to solve an issue I have with the root locus plot.
This is my code
NUM{1,1}=[-15,-300];
DEN{1,1}=[1,0];
G_idref_vdcref = tf(NUM{1,1},DEN{1,1});
Try this:
n=[15,300];
d=[1,0];
G_idref_vdcref = tf(n,d)
the minus signs are the problem
rlocus(G_idref_vdcref);
hold on
n_idref_vdcref=roots(NUM{1,1})
d_idref_vdcref=roots(DEN{1,1})
plot(real(n_idref_vdcref),imag(n_idref_vdcref),"co"," markersize",15)
plot(real(d_idref_vdcref),imag(d_idref_vdcref),"rx"," markersize",15)
And the resulting root locus plot is:
<http://octave.1599824.n4.nabble.com/file/t372684/ >rlocusplot1.jpg
what is obvious, incorrect, since in my transfer fuction there is a pole at
s=0 and a zero at s=-20, and in the picture we see that the rlocus line goes
to instability and other areas that it is not supposed to go. If I zoom the
rlocus plot we see:
<http://octave.1599824.n4.nabble.com/file/t372684/ >rlocusplot2.jpg
Where the zero and the pole are correctly located, however the connecting
line between them is uncorrect. Any suggestion to solve this error?
Thanks.
--
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