Questions tagged [root-locus]
43 questions
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What is the practical advantage of root locus method in control system engineering?
Recently I learned about the topic.
Decades ago, when no computational power was available for engineers, it was surely helpful in some way. But I do not understand what the advantage is nowadays, because with any math-tool I can compute poles for a…
MichaelW
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3
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Pole Zero Cancellation on a Root Locus
Problem Design a controller in the feed-forward path to minimize the effects of the two pairs of dominant poles. Use the pole-zero cancellation technique via the root locus diagram.
I have a 5\$^{th}\$ order system with two pairs of dominant poles,
…
rrz0
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Determining imaginary axis crossing of a root locus
I have an equation \begin{equation}{\text{L}\left(s\right)=\frac{K}{s(s+4)(s^2+6s+64)}} \end{equation}
and I am trying to determine it's root locus by hand.When I try plotting it with matlab, the root locus seems to cross the imaginary axis at about…
Ca01an
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Root Locus in a feedback loop
I'm trying to draw Root Locus by hand from the following block diagram and confirm the result I got from Routh Hurwitz's table:
The table of Routh Hurwitz that I got is the following:
And from the stability conditions I got K> 0.
I calculate the…
Carmen González
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1 answer
Does this Root Locus analysis contradict my understanding of Nyquist stability criteria?
I have been trying to theoretically analyse the operation of a 741 op-amp from a stability point of view by firstly deriving its open-loop transfer function.
Here is the magnitude plot of a 741 op-amp.
From the above plot, I generated the open-loop…
user173271
2
votes
2 answers
Relationship between root locus pole and percent overshoot and gain in MATLAB
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%:
using…
Rando
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Root Locus and Imaginary Axis
I’m having some serious issues finding the point at which the root loci cross the imaginary axis for the following Open Loop Transfer Function (OLTF) ;
We have been taught to substitute s = jw and multiply by the complex conjugate in order to have…
JakeNorms
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What does the root locus tell us exactly?
More specifically what information can one extract from a root locus drawing without calculating the transfer function and then using Routh Hurwitz or other techniques? Essentially, what information does the Root Locus alone give us?
Ahsan Yousaf
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Unable to determine transfer function to obtain root locus
This one is pretty straightforward. We set K1 = 4 and want to bring out K2 as a common factor so we can plot the root locus for the system. The correct answer is:
$$\small G_{new}(s)=4K_2\frac{(s+6)}{(s-2)(s+6)+20}$$
I can't think of any algebraic…
Or Perez
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PID - Root Locus (Sisotool) for Transfer Function (TF) with Zero and Poles in Right Plane
I have a 8th order transfer function, you can see it in the first image:
% Transfer function
num = [2.091,0,203.3,0,-2151,0,-1.072e05];
den = [1,0,-830.4,0,-1.036e05,0,-5.767e05,0,2.412e07];
tf = tf(num, den)
I need to use a PID, so I'm trying to…
Brian1776
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vote
1 answer
Trouble with meeting design specifications of a second order system using Matlab
I am trying to solve the following question.
Consider the transfer function $$G(s) = \frac{1.247}{s^2+9.76s+23.8}$$ is in the forward path of a unity feedback control loop. Assume that it is compensated using a static gain K in the forward path. Now…
Michio Kaku
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Phase Lag Compensator
I have a question on lag compensators in general.
Why do they increase both the rise time and the settling time? Is it due to the introduction of a slow pole?
Much thanks!
aid846
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How do I plot the root locus when there are multiple controller gains?
I am trying to design a closed loop system with a PI controller. I have plotted root loci before, but in those, I had assumed that the controller was only Proportional. This gave a characteristic equation of the form:
1 + K*(n(s)/d(s)) = 0
where K…
Francis Vellara
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Centroid from calculated root locus is different to the one from MATLAB
Hi all hope someone can help me here.
My problem involves the transfer function
G(s)=(s+32.8)/((s+2.8)(s+5)(s+27.8) )
As far as im concerned the centroid is calculated using
σ_a= (Ʃpoles - Ʃzeros) / (# of poles - # of zeros)
From my…
dorudrakky
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Design a digital controller for minimize the settling time
I have a system of digital control with unitary feedback, with the following transfer function:
$$G(z)=2\frac{(z-0.5)(z-2)}{(z+0.2)(z+1.5)}$$
I need to use a digital controller:
$$C(z)=K\frac{z-\beta}{z-\alpha}$$
And the purpose is minimize the…
Carmen González
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