I have a peculiar confusion regarding the relationship between a closed-loop pole on a root locus plot and its gain and percent overshoot. I have found a point on the root locus plot that MATLAB claims to have a percentage overshoot of 5%: https://i.imgur.com/UqwJciZ.png using the following code:
s = tf('s'); gproc = ((s+3)*(s+6))/(s^2*(s+2)); rlocus(gproc); % plot root locus
However, when I plot the step response, the percent overshoot seems to be 22%: https://i.imgur.com/CJejh4s.png using the following code:
gopen = 13.71*gproc; step(feedback(gopen,1));
What is the reason for this discrepancy? Have I misunderstood the MATLAB code?