# Questions tagged [root-locus]

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### Is it possible to find the point at which the root locus crosses the damping ratio line?

I am aware of how the intersection of the root locus plot can be found with a second order system; however, I was wondering how would you find the intersection by hand (without MATLAB) of a higher ...
178 views

### What is the practical advantage of root locus method in control system engineering? [closed]

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, ...
1 vote
123 views

### 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(...
51 views

### Which of the following methods tells Absolute stability & which method tells Relative Stability? Bode Plot, Routh Hurwitz, Root Locus, Nyquist PlotC

Which of the following methods tells Absolute stability & which method tells Relative Stability? I. Bode Plot ii. Routh Hurwitz iii. Root Locus iv. Nyquist Plot What i think is the following ...
1 vote
52 views

### 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 ...
35 views

### How to move closed loop pole to meet the design requirements for settling time and overshoot?

I have tried adding a lead compensator as shown in the second image however am now confused as to how to move the closed loop pole on the right into the feasible region. The first image shows the ...
148 views

### Break away/Break in angle in Root Locus method

We are learning Root Locus in our introductory controls course, and one thing has really been confusing me. When the poles are on real axis, is the breakaway angle always 90 degrees? Is there a simple ...
82 views

### Root Locus of the system

How can I plot root locus like these system can you help me?
62 views

### Finding $\small K$ for a given $\small\zeta$ value when $\omega_n$ (frequency) is not given

Here $\omega_n$ (frequency) is not given. Then upon plotting the Root Locus, how will we find $\small K$ at $\small\zeta = 0.5$ if we're not using a graph sheet and want to find everything ...
1 vote
51 views

### 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!
74 views

### What is meant by "T" and "aT" here?

https://ctms.engin.umich.edu/CTMS/index.php?example=BallBeam&section=ControlFrequency I am trying to learn about lead compensator from above link But i have bit confusion regarding two terms,"...
1 vote
114 views

### 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 ...
245 views

### Determine range of proportional gain with given overshoot

I have given the open-loop transfer function $$G_{ol} = 1.42 \frac{(s+3)^2+6^2}{(s-1)(s+2)((s+4)^2+4^2)}$$ The task I was given is determining the range of the proportional gain, which makes the ...
1 vote
347 views

### 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 ...
106 views

### No breakaway points , No imaginary axis crossing points and No angle of departure

G(s)H(s) = K(s+1)/[s^2(s+2)(s+4)] According to my calculations there are 4 poles (0,0,-2,-4) and 1 zero (-1) in this system.No of branches are 3.The centroid is -1.67 and the angles of asymptote ...
2k views

### How to find the gain K at break-in and breakaway points of a Root Locus Plot on MATLAB

I would like to know how to find the break-in and breakaway points of a transfer function using root locus on MATLAB. MATLAB Code: ...