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    control system, poles and stability response

    Can you help me compare these results? They're the simulations of a closed loop system . When we change the poles, (in this case, there are 4 poles), the response system also changes. The 4 poles involves 2 complex numbers and 2 integers, but I don't see the relationship between the poles and the response. I don't see an exact description. I mean, a description like:
    if the real number is increased, then the response would be more oscillatory or if the imaginary part is smaller, then the faster the convergence to 0.
    Help, please?

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    •   Alt25th November 2013, 02:38

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  2. #2
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    Re: control system, poles and stability response

    Can you help me compare these results? They're the simulations of a closed loop system . When we change the poles, (in this case, there are 4 poles), the response system also changes. The 4 poles involves 2 complex numbers and 2 integers, but I don't see the relationship between the poles and the response. I don't see an exact description. I mean, a description like:
    if the real number is increased, then the response would be more oscillatory or if the imaginary part is smaller, then the faster the convergence to 0.
    Help, please?

    Hi MissP.25_5

    I don't see anything surprising ! when you change location of poles of a circuit response of a circuit will be involved by some changes which depends on where are the poles exactly .

    A suitable Article from MIT can lead you through a good understanding :

    http://www.google.com/url?sa=t&rct=j...56988011,d.cGU


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    Goldsmith
    When you sensed that i can help you , feel free to ask me .
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    The only thing that i couldn't understand yet , is why humans should fight together ? why not helping each other to have a better world ?



    •   Alt25th November 2013, 04:03

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    Re: control system, poles and stability response

    Quote Originally Posted by goldsmith View Post
    Hi MissP.25_5

    I don't see anything surprising ! when you change location of poles of a circuit response of a circuit will be involved by some changes which depends on where are the poles exactly .

    A suitable Article from MIT can lead you through a good understanding :

    http://www.google.com/url?sa=t&rct=j...56988011,d.cGU


    Best Wishes
    Goldsmith
    Yes, that's what I said. The response depends on the poles. But I need to compare these 3 results. They're the results of 3 different poles. I also need to write the relationship between the complex numbers and the response. Can you help?



    •   Alt25th November 2013, 04:25

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    Re: control system, poles and stability response

    MissP - it is not easy to answer your question because it is not clear which parameters of the closed-loop sysytem are shown.
    Watching the first line I see something like a step response, correct?
    In this context, I am confused about the last line showing an input. Which input?

    As a general (and preliminary) answer:
    A complex pole pair causes overshoot in the step response. When the (negative) real part of these poles come closer to the origin (imag. parts constant) the overshoot increases.
    Moreover, a negative real pole (at s=-sigma) causes a damping of the step response corresponding to exp(-sigma*t). Thus, the duration of the step response is inverse proportional to sigma.
    I think, the time response (first line) can confirm these statements.
    Last edited by LvW; 25th November 2013 at 09:52.


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    Re: control system, poles and stability response

    Quote Originally Posted by LvW View Post
    MissP - it is not easy to answer your question because it is not clear which parameters of the closed-loop sysytem are shown.
    Watching the first line I see something like a step response, correct?
    In this context, I am confused about the last line showing an input. Which input?

    As a general (and preliminary) answer:
    A complex pole pair causes overshoot in the step response. When the (negative) real part of these poles come closer to the origin (imag. parts constant) the overshoot increases.
    Moreover, a negative real pole (at s=-sigma) causes a damping of the step response corresponding to exp(-sigma*t). Thus, the duration of the step response is inverse proportional to sigma.
    I think, the time response (first line) can confirm these statements.
    The input is the voltage input used to produce the torque for the pendulum arm to oscillate. The poles consist of 2 pair of real numbers and 2 pairs of conjugate numbers. What do the real numbers say about the response?



    •   Alt25th November 2013, 10:18

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    Re: control system, poles and stability response

    Quote Originally Posted by MissP.25_5 View Post
    The input is the voltage input used to produce the torque for the pendulum arm to oscillate. The poles consist of 2 pair of real numbers and 2 pairs of conjugate numbers. What do the real numbers say about the response?
    Sorry to say but your answers do not clarify things.
    However, at least I have learned that the system input is NOT a voltage step - correct?
    In this case, it is rather complicated to verify/justify/explain the system response.


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