1. Not finding help here? Sign up for a free 30min 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!

Transfer function algebraic manipulation

  1. Nov 7, 2015 #1

    Maylis

    User Avatar
    Gold Member

    1. The problem statement, all variables and given/known data
    upload_2015-11-7_14-2-6.png

    2. Relevant equations


    3. The attempt at a solution
    I don't know if I am just stupid, but I can't see how to make this manipulation. I tried factoring the denominator

    $$ g_{p} = \frac {-1.43}{(s-1.399)(s+5.086)} $$
    Then take out -1.399 and 5.086
    $$ g_{p} = \frac {-1.43}{-1.399(\frac {-1}{1.399}s + 1)5.086(\frac {1}{5.086}s+1)} $$
    But I know this won't work, and I am not clever enough right now to come up with the right way to manipulate this thing.
     
  2. jcsd
  3. Nov 7, 2015 #2

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    Your manipulations are correct; it is just that one of your constants ##\tau_i## is negative. If that is not allowed, there must be something wrong with the original ##g_p(s)##.
     
  4. Nov 7, 2015 #3

    Maylis

    User Avatar
    Gold Member

    The negative time constant is allowed, which is what makes it unstable. My algebra is weak, so for some reason I had it in my head that if I multiplied my result out, I would come up with something different from the original transfer function!
     
  5. Nov 7, 2015 #4

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    You've almost got the form of gp(s) that is specified, you just need to combine all the constants in the numerator and the denominator.

    Hint: kp ≠ -1.43 in the final form.
     
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: Transfer function algebraic manipulation
  1. Algebraic Manipulation (Replies: 9)

  2. Algebraic Manipulation (Replies: 4)

  3. Algebra manipulation (Replies: 2)

  4. Algebraic Manipulation (Replies: 2)

  5. Algebraic Manipulation (Replies: 13)

Loading...