6 Program 6.7 OGATA 4edition (root locus, damping ratio)

Let us calculate the roots-locus with indication of damping ratio =0.5 by Scilab, a closed loop system with feedback unit whose transfer function in open-loop is:

Program in Scilab num=poly([1 0 0 0],'s','coeff'); den=poly([0 5 4 1],'s','coeff'); g=syslin('c',num/den); evans(g); clf; v=[-3 1 -2 2]; mtlb_axis(v) sgrid([0.5],[0],32);