Using overshoot and settling time formula to determine pole location?












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Is it possible to use the formula for overshoot and settling to determine where where ones pole should. by using the overshoot and settling time formula i mean, using it to define what $zeta$ and $omega_n$ should be, and using them to determine the pole location since a pole is defined as $zeta omega_n pm sqrt{1- zeta^2}$ ..



So if we said that i wanted overshoot to be 0 % => $zeta = 1$ and a settling time to be less than 2, $2>omega_n$...
This just seems incorrect, because be doing so i am letting $omega_n$ become negativ, which lead the the pole to located at the RHS, which would make the system unstable, which make me question if this method is correct??



I have this close loop transfer function
http://snag.gy/Vh1SM.jpg
Which overshoots, but why does it overshoot?? The poles are placed such that that the damping = 1... so why do get overshoot??










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    Is it possible to use the formula for overshoot and settling to determine where where ones pole should. by using the overshoot and settling time formula i mean, using it to define what $zeta$ and $omega_n$ should be, and using them to determine the pole location since a pole is defined as $zeta omega_n pm sqrt{1- zeta^2}$ ..



    So if we said that i wanted overshoot to be 0 % => $zeta = 1$ and a settling time to be less than 2, $2>omega_n$...
    This just seems incorrect, because be doing so i am letting $omega_n$ become negativ, which lead the the pole to located at the RHS, which would make the system unstable, which make me question if this method is correct??



    I have this close loop transfer function
    http://snag.gy/Vh1SM.jpg
    Which overshoots, but why does it overshoot?? The poles are placed such that that the damping = 1... so why do get overshoot??










    share|cite|improve this question



























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      Is it possible to use the formula for overshoot and settling to determine where where ones pole should. by using the overshoot and settling time formula i mean, using it to define what $zeta$ and $omega_n$ should be, and using them to determine the pole location since a pole is defined as $zeta omega_n pm sqrt{1- zeta^2}$ ..



      So if we said that i wanted overshoot to be 0 % => $zeta = 1$ and a settling time to be less than 2, $2>omega_n$...
      This just seems incorrect, because be doing so i am letting $omega_n$ become negativ, which lead the the pole to located at the RHS, which would make the system unstable, which make me question if this method is correct??



      I have this close loop transfer function
      http://snag.gy/Vh1SM.jpg
      Which overshoots, but why does it overshoot?? The poles are placed such that that the damping = 1... so why do get overshoot??










      share|cite|improve this question















      Is it possible to use the formula for overshoot and settling to determine where where ones pole should. by using the overshoot and settling time formula i mean, using it to define what $zeta$ and $omega_n$ should be, and using them to determine the pole location since a pole is defined as $zeta omega_n pm sqrt{1- zeta^2}$ ..



      So if we said that i wanted overshoot to be 0 % => $zeta = 1$ and a settling time to be less than 2, $2>omega_n$...
      This just seems incorrect, because be doing so i am letting $omega_n$ become negativ, which lead the the pole to located at the RHS, which would make the system unstable, which make me question if this method is correct??



      I have this close loop transfer function
      http://snag.gy/Vh1SM.jpg
      Which overshoots, but why does it overshoot?? The poles are placed such that that the damping = 1... so why do get overshoot??







      control-theory






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      edited May 17 '14 at 17:19

























      asked May 17 '14 at 12:49









      newbiemath

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          Sure you can determine where the poles should be, in fact there are many design methods exists using this. The pole locations you provided are wrong, it should be $p_{1,2} = - zeta omega_n mp i omega_n sqrt{1 - zeta^2}$.



          The settling time formula for %2 band is $t_s = frac{4}{zeta omega_n}$ which should result in $omega_n = 2$.



          The system you provided overshoots because of the zero of the system. System zeros increase overshoot especially when they are close to the imaginary axis. The overshoot formula is calculated for the system with no zeros.






          share|cite|improve this answer





















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            Sure you can determine where the poles should be, in fact there are many design methods exists using this. The pole locations you provided are wrong, it should be $p_{1,2} = - zeta omega_n mp i omega_n sqrt{1 - zeta^2}$.



            The settling time formula for %2 band is $t_s = frac{4}{zeta omega_n}$ which should result in $omega_n = 2$.



            The system you provided overshoots because of the zero of the system. System zeros increase overshoot especially when they are close to the imaginary axis. The overshoot formula is calculated for the system with no zeros.






            share|cite|improve this answer


























              0














              Sure you can determine where the poles should be, in fact there are many design methods exists using this. The pole locations you provided are wrong, it should be $p_{1,2} = - zeta omega_n mp i omega_n sqrt{1 - zeta^2}$.



              The settling time formula for %2 band is $t_s = frac{4}{zeta omega_n}$ which should result in $omega_n = 2$.



              The system you provided overshoots because of the zero of the system. System zeros increase overshoot especially when they are close to the imaginary axis. The overshoot formula is calculated for the system with no zeros.






              share|cite|improve this answer
























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                Sure you can determine where the poles should be, in fact there are many design methods exists using this. The pole locations you provided are wrong, it should be $p_{1,2} = - zeta omega_n mp i omega_n sqrt{1 - zeta^2}$.



                The settling time formula for %2 band is $t_s = frac{4}{zeta omega_n}$ which should result in $omega_n = 2$.



                The system you provided overshoots because of the zero of the system. System zeros increase overshoot especially when they are close to the imaginary axis. The overshoot formula is calculated for the system with no zeros.






                share|cite|improve this answer












                Sure you can determine where the poles should be, in fact there are many design methods exists using this. The pole locations you provided are wrong, it should be $p_{1,2} = - zeta omega_n mp i omega_n sqrt{1 - zeta^2}$.



                The settling time formula for %2 band is $t_s = frac{4}{zeta omega_n}$ which should result in $omega_n = 2$.



                The system you provided overshoots because of the zero of the system. System zeros increase overshoot especially when they are close to the imaginary axis. The overshoot formula is calculated for the system with no zeros.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Dec 20 '14 at 10:56









                obareey

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