%part A
%%
%q1
J=200;
B=150;
tao=0.2;
K=1; %for simulink diagram only
%%
%q3
s=tf('s')
G_motor=55/(tao*s+1);
G_antenna=1/(J*s^2+B*s);
G=G_motor*G_antenna
figure(1)
rlocus(G);
grid on
%%
%q4
a=(0.2*s+1)/(40*s^3+230*s^2+150*s+55);
figure(2)
bode(a)
grid on

C=(6*(5.3*s+1)*(s+1)*(0.19*s+1))/(s*(1+0.01*s)*(1+0.02*s));
GC_cl=minreal(G*C/(1+G*C));%H=1
q5poles=pole(GC_cl)
G_diturbance = G_antenna/(1+C*G);%H=1
figure(3)
bode(G_diturbance)
grid on
%%
%q7+8
stepinfo(out.simout.Data,out.simout.time,'SettlingTimeThreshold',0.05)
%%
% part B
%q1
B_max=1.1*B;
B_min=0.9*B;
J_max=1.1*J;
J_min=0.9*J;
G2=[1/(J_max*s^2+B_max*s) 1/(J_max*s^2+B_min*s) 1/(J_min*s^2+B_max*s) 1/(J_min*s^2+B_min*s)];
for i=1:4
    G=G_motor*G2(i);
    G_diturbance2(i) = G2(i)/(1+C*G);%H=1
    figure(i+3)
    bode(G_diturbance2(i))
    grid on
end
%%
%q3
sti=stepinfo(out.simout.Data,out.simout.time,'SettlingTimeThreshold',0.05);
if sti.RiseTime<0.3 && sti.SettlingTime<3  && sti.Overshoot<10 %find which variance the system can manage
    check='ok'
else
    check='no'
end