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## Homework Statement

I have to design a controller for "Cruise Control System" using Root Locus method.

## Homework Equations

We havnt studied that method yet and nor do I think it is in the course outline. Actually that is why I selected root locus so that I can learn something beyond the course for Control System.

## The Attempt at a Solution

Luckily I found the project online. http://www.engin.umich.edu/class/ctms/examples/cruise/ccrl.htm"

The problem is in understanding the method itself. I have referred to many books but I am still not able to catch the real deal. I will start with the basic problems I have.

1. How many poles/zeros do we move to make the system stable?

2. How do we know that we have to move poles only or zeros only or both ?

3. Referring to the above link. Doesnt the two dotted lines (under "Proportional controller") and the dotted semi circle bound all the points which will give the desired rise time and overshoot ? Why do they don't when the criteria for those lines and semicircle is set?

4. Referring to the above link. I do not understand the part under "Proportional controller" where after plotting the root locus (I understand the plotting part quite fine) it is written to chose "-0.4" as the pole. Now the confusion is that there are million points between the dotted lines and the dotted semi-circle, so how do I know that which one will give the desired rise time and overshoot.

Will be waiting anxiously for reply....

Thanks in advance

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