G = tf(160, [1, 16, 160])

rlocus(G)

%% 

K1 = 0.374

Phi = -4.85 + 12.57i

theta_c = pi - angle(evalfr(G, Phi))

pld = -80
zld = real(Phi) - abs(imag(Phi)) / tan(theta_c + angle(Phi - pld))

Cld = zpk(zld, pld, 1)

rlocus(-Cld * G)

%%

K2 = -2.73

sys_ol = K2 * Cld * G

Kp = evalfr(sys_ol, 0)
ss_error = 1 / (1 + Kp)

step(feedback(sys_ol, 1))

stepinfo(feedback(sys_ol, 1))

%%

alpha = ss_error / 0.05