Root Locus
Root Locus
Root Locus
AIM
Plot the root locus of the given transfer function to analyse the following using simulation:
THEORY
Root-locus defines as a graph of the poles of the closed-loop transfer function as the system
parameter, such as the gain is varied The root locus of an (open-loop) transfer function is a
plot of the locations (locus) of all possible closed-loop poles with some parameter, often a
proportional gain , varied between 0 and . The figure below shows a unity-feedback
architecture
G(s)
and thus the poles of the closed-loop system are values of such that 1+K G(s)=0.
PLOTTING THE ROOT LOCUS OF A TRANSFER FUNCTION
Aim 1.
Verification of the critical gain, wo with the theoretical values
AIM : 2
The effect of controller gain K on the stability.
K=1
STABLE SYSTEM K=10
FREQ -2.83 rad/sec STABLE SYSTEM
FREQ -2.83 rad/sec
K=48
Marginally STABLE
K=40 SYSTEM
STABLE SYSTEM
K=60
unSTABLE SYSTEM
clc
s=tf('s')
gh=1/((s)*(s+2)*(s+4))
k=1
t=gh*k
den=[1 6 8 0]
poles=roots(den)
pzmap(t)
m=feedback(gh*k,1)
for k = 1:10:110;
pzmap (feedback(gh*k,1));
hold on;
end
figure
rlocus(t)
stepinfo(m)
sisotool(gh)
RESULT
Root Locus Of The Given Transfer Function Is Ploted In Matlab And Analysed The Given Aims