1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Centroid of a root locus

  1. Feb 4, 2012 #1
    i just want to make sure i'm doing this correctly as there is some discrepancy in my textbook. i know the centroid is equal to (Ʃpoles - Ʃzeros) / (# of poles - # of zeros)

    the equation i have is s2 + 2s + 8 / s(s2 + 2s + 10)

    so the zeros are -1 + i√7 and -1 - i√7
    and the poles are 0, -1 + 3i, -1 - 3i

    and the centroid = (0 - 1 - 1) - (-1 -1) / (3-2) = 0

    in my textbook they say that the answer is -2.. am i missing something?
    my textbook has been wrong before........
     
  2. jcsd
  3. Sep 18, 2015 #2
    (0-2)/1= -2 The 2nd order pole is complex. The sum of the roots are 0. The zeros should be (-4,2) {not -1-1 as shown} or -4+2=-2. Your denominator calculation is correct that 3poles -2zeros is 1. The correct answer should be -2
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Centroid of a root locus
  1. Root locus varying H (Replies: 3)

  2. Root Locus Sketching (Replies: 2)

  3. Root locus question (Replies: 4)

Loading...