9 Program 6.10 OGATA 4edition (root locus, gain)

Laplace.T	Root-locus	Transient response	Frecuency response

9 Program 6.10 OGATA 4edition (root locus, gain)

Let us calculate the root-locus of a closed-loop system with feedback by Scilab, whose transfer function in open loop is:

$\begin{displaymath}G(s)=\frac{K\cdot(s^{2}+2\cdot s+4)}{s\cdot (s+4)\cdot (s+6)\cdot (s^{2}+1.4\cdot s+1)}\end{displaymath}$
Program in Scilab
s=%s;
num=s^2+2*s+4;
den=s*(s+4)*(s+6)*(s^2+1.4*s+1);
g=syslin('c',num/den);
clf;
evans(g);
v=[-7 3 -6 6];
mtlb_axis(v);
xgrid;
xstring(0,1,'K=12');
xstring(0,2,'K=73');
xstring(0,3.5,'K=154');