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Homework Help: Control Systems - Root Locus with proportional control

  1. Mar 8, 2014 #1
    1. The problem statement, all variables and given/known data


    2. Relevant equations

    See below

    3. The attempt at a solution

    Root Locus? Easy Peasy right? Based on provided equation G(s), i solved the coordinates of the root locus diagram using quadratic equation.

    For the 2nd part of the question, i have to find gain at which rise time is 1 second. With previous sample questions, we would use s^2 + 2zWs + W^2 for the 2nd order denominator to finish the question based on given parameters (ie dampening ratio, percentage overshoot etc). How do i deal with the numerator?

  2. jcsd
  3. Mar 9, 2014 #2


    User Avatar
    Gold Member

    I cannot remember root locus at all. sorry

    that being said matlab will do a root locus plot for you
    you can use that to check your work. I havent done root locus by hand since I was required too in school.

    note: Make sure you understand the material for your tests. for now only use matlab as a tool to help you check your answer. Do not just copy the graph to a piece of paper.

  4. Mar 9, 2014 #3
    I actually just figured it out!. If you create a transfer function using G and C, you can easily match it up to the characteristic equation for 2nd order systems and solve accordingly. I double checked this on matlab so i know its the correct approach.
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