clc; clear
close all

% En dominio continuo
s=tf('s');
Gp=1/(s*(s+2));
Gplc=feedback(Gp,1);
Gc=9*(s+2)/(s+3);
Gla=Gc*Gp;
Glc=feedback(Gla,1);

step(Glc,Gplc);
legend('Sistema Compensado','Sistema No Compensado')
% 
figure; margin(Gla)
figure; bode(Glc)

% Selección del periodo de muestreo
wn=3; xita=0.5; wd=wn*sqrt(1-xita^2);
Nd=100; % muestras x periodo de oscilación
Td=wd/2/pi;
T=Td/Nd;

% En el dominio de tiempo discreto
% T=0.001;
td=0:T:5-T;
ref1=ones(length(td),1);
z=tf('z',T);
Gpd=c2d(Gp,T);

% Primera aproximación: Residuos
% Gcd=c2d(Gc,T);
Gcd1=(9*z-6*exp(-3*T)-3)/(z-exp(-3*T));
Glad1=Gcd1*Gpd;
Glcd1=feedback(Glad1,1);

% Segunda aproximación: Backward
Gcd2=(9 + 18*T - 9*z^-1)/(1 + 3*T - z^-1);
Glad2=Gcd2*Gpd;
Glcd2=feedback(Glad2,1);

% Tercera aproximación: Forward
Gcd3=(9 + (18*T - 9)*z^-1)/(1 + (3*T - 1)*z^-1);
Glad3=Gcd3*Gpd;
Glcd3=feedback(Glad3,1);

% Cuarta aproximación: Tustin
Gcd4=(18 + 18*T + (18*T - 18)*z^-1)/(2 + 3*T + (3*T - 2)*z^-1);
Glad4=Gcd4*Gpd;
Glcd4=feedback(Glad4,1);

figure; step(Glc,Glcd1,Glcd2,Glcd3,Glcd4,td); 
legend('SC en Tiempo Continuo','SCTD Aprox. Residuos','SCTD Aprox. Backward','SCTD Aprox. Forward','SCTD Aprox. Tustin')


figure; bode(Gla,Glad1,Glad2,Glad3,Glad4); grid
legend('SC en Tiempo Continuo','SCTD Aprox. Residuos','SCTD Aprox. Backward','SCTD Aprox. Forward','SCTD Aprox. Tustin')
figure; bode(Glc,Glcd1,Glcd2,Glcd3,Glcd4); grid
legend('SC en Tiempo Continuo','SCTD Aprox. Residuos','SCTD Aprox. Backward','SCTD Aprox. Forward','SCTD Aprox. Tustin')
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