Hi Nico,
Although it might seem like the step response for gain values do not approach the steady state value of 1, this might be because it reaches steady state at a later stage due to the value of K chosen. To observe that, we can change the tFinal input argument for the stepplot command final time for step response computation to be a very high value, say 100.
Here is a script that illustrates how to change the tFinal value:
tau = 0.1;
G_plant = tf(1,[tau 1]);
alpha = 0.2;
Gc = tf([1 alpha],[1 0]);
K = 5:0.4:9;
for i=1:length(K)
G_openloop = Gc*G_plant;
T = feedback(K(i)*G_openloop,1);
hold on
stepplot(T,100);
end
hold off
Hope this helps!
