Examples
H=syslin('c',352*poly(-5,'s')/poly([0,0,2000,200,25,1],'s','c')); clf();evans(H,100);sgrid() [Ki,s]=kpure(H) // Gains that give pure imaginary closed loop poles plot([real(s) real(s)],[imag(s) -imag(s)],'*r') [Kr,s]=krac2(H) |  |  |
Evans root locus
evans(H [,kmax])
SISO linear system given by a transfer or a state space representation (see:syslin).
real (maximum gain desired for the plot )
Gives the Evans root locus for a SISO linear system in state-space or
transfer form H(s) (syslin). This is
the locus of the roots of
1+k*H(s)=1+k*N(s)/D(s), in the complex
plane. For a selected sample of gains k <=
kmax
,the imaginary part of the roots of
D(s)+k*N(s) is plotted vs the real part.
To obtain the gain at a given point of the locus you can activate the datatips manager and click the desired point on the root locus.
H=syslin('c',352*poly(-5,'s')/poly([0,0,2000,200,25,1],'s','c')); clf();evans(H,100);sgrid() [Ki,s]=kpure(H) // Gains that give pure imaginary closed loop poles plot([real(s) real(s)],[imag(s) -imag(s)],'*r') [Kr,s]=krac2(H) | | |