Hi everyone. Hope U fine.

I have to sketch the root locus and determine the gain K that satisfies the mentioned specifications .
The problem is how to treat the controller with the 'K' and what command should i use to do saticfy the specifications??

look at the attached files

 

The rules of constructing a root locus are quite explicit. You have in the forward path a controller with three possible transfer functions and you have a plant or system with a fixed transfer function. The feedback connection has a transfer function of unity. Among the first rules of constructing a root locus is figuring out how many poles and how many zeros there are, followed quickly by how many branches there are. Where do they begin and where do they end as a function of the parameter K. Can you at least get that far with the three examples?

Side point:
What is the open-loop transfer function?
What is the closed loop transfer function?
Why are they both important for this analysis?

 

the problem is that i don't know what commands should i use and what are the procedures?? @Papabravo

 

the problem is that i don't know what commands should i use and what are the procedures?? @Papabravo

lol
In my Controls class (third year of four year program) we did it by hand. If you knew how do it by hand, then you would have known the formulas and steps to apply those formulas. The fact that you don't know any of it... is not encouraging.

 

u r right i don't know how to do it.....can u help me??? @shteii01

 

u r right i don't know how to do it.....can u help me??? @shteii01

No, it would be too painful to do it over the internetz.

If you can do this problem on paper, then you can later write the MatLab m-file.

 

this is the problem i don't know hoe to do it on paper?!!!!

if u can link me a useful website that talks about it or a pdf!!! @shteii01

 

this is the problem i don't know hoe to do it on paper?!!!!

if u can link me a useful website that talks about it or a pdf!!! @shteii01

I dug up this from my professor's website:
Control Tutorials for Matlab and Simulink at Univ. of Michigan
http://ctms.engin.umich.edu/CTMS/index.php?example=Introduction&section=ControlRootLocus

 

AFAIK there are no canned commands in MATLAB to do a root locus. You have to apply a series of steps that allow you to sketch it. This method was developed in the days before computers were widely available, and it requires a deep understanding of open and closed loop transfer functions. Without that deep understanding any explanation I could offer would go in one ear and out the other. Go back and study the material again and try to answer the basic questions.

1. How many poles and zeros are we dealing with?
2. How many branches are there?
3. Where do the branches of the locus begin and end?

The answers to these questions require counting and high school algebra -- nothing more.

 

I dug up this from my professor's website:
Control Tutorials for Matlab and Simulink at Univ. of Michigan
http://ctms.engin.umich.edu/CTMS/index.php?example=Introduction&section=ControlRootLocus

U of M 1969, 1970, 2004 Go Blue!