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!

Finding the settling time

  1. Nov 15, 2008 #1
    a)find time constant of the closed loop system.(take R(s)=1/s and D(s))

    b) find the settling time(within 2% of the final value when R(s)=1/s and D(s)=1/s

    solution for part 1a
    H(s)=Y(s)/R(s)=G(s)/s/1+G(s)(1/s)/s= (k/s+10)/s/((1+(k/s+10)(1/s)/s)
    constant time should equal to 1/30 sec

    stuck on 1b need help
  2. jcsd
  3. Nov 16, 2008 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Welcome to PF.

    It has been a long time since I worked with Laplace transforms, but does the signal behave as a straightforward exponential decay towards the final value? If so, simply solve for when the exponential is 2%, using the time constant you have.
  4. Nov 18, 2008 #3


    User Avatar

    Find the dominant poles of your TF. They should be of the form [tex]-\sigma\pm j\omega[/tex]. The settling time is [tex]\frac{4}{\sigma}[/tex]
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Finding the settling time