I am having some problems (or so do i think) making matlab draw a root locus diagram of closed loop system.
I have this close loop transfer function $T(S) = \frac{\frac{K_p}{s(s+1)} + \frac{K_iS}{s(s+1)} + \frac{K_d}{s(s(s+1))}}{1+\frac{K_p}{s(s+1)} + \frac{K_iS}{s(s+1)} + \frac{K_d}{s(s(s+1))}}$
Where i want to see how the poles are affected when K_p , K_i or K_d is changed. But i am having problems writing it in write form, in which the matlab function sees those parameter as the changing one. I am kinda suspecting that it is just mutiplying a random gain to the system.
The way i've done it is i've reset each K_i and K_d, and plotted K_p and tried to plot K_p as being one. But that is clearly the wrong way to do, or so do i think.
this is the code i've been plotting. rlocus(tf([1 ],[1 1 1]))
My problem is basically an isolation problems. I need to isolate the denominatior such as the wanted gain appears as an gain for the whole system.