5.4.6 Some Classical Graphics for Automatic Control

• bode : plot magnitude and phase of the frequency response of a linear system.

• gainplot : same as bode but plots only the magnitude of the frequency response.

• nyquist : plot of imaginary part versus real part of the frequency response of a linear system.

• m_circle : M-circle plot used with nyquist plot.

• chart : plot the Nichols'chart

• black : plot the Black's diagram (Nichols'chart) for a linear system.

• evans : plot the Evans root locus for a linear system.

• plzr : pole-zero plot of the linear system

s=poly(0,'s');
h=syslin('c',(s^2+2*0.9*10*s+100)/(s^2+2*0.3*10.1*s+102.01));
h1=h*syslin('c',(s^2+2*0.1*15.1*s+228.01)/(s^2+2*0.9*15*s+225));
//bode
subplot(2,2,1)
gainplot([h1;h],0.01,100);
//nyquist
subplot(2,2,2)
nyquist([h1;h])

//chart and black 
subplot(2,2,3)
black([h1;h],0.01,100,['h1';'h'])
chart([-8 -6 -4],[80 120],list(1,0));
//evans
subplot(2,2,4)
H=syslin('c',352*poly(-5,'s')/poly([0,0,2000,200,25,1],'s','c'));
evans(H,100)

Figure 5.8: Some Plots in Automatic Control