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  1. K

    MATLAB nyquist plot help needed

    i understand that the "nyquist" command in matlab requires one to key in the transfer function.. however, i am stuck here as i am unable to form a transfer function from the following numerator and denominator: num = s-3/2-1/2*(-24*s+1)^(1/2) den = 1.25*s^2 +3.75*s + 2.5 i know that...
  2. K

    Engineering DC Motor

    Homework Statement A separately excited DC motor with 220V, 970rpm, 100A and Ra=0.05ohms. It is braked by plugging from an initial speed of 1000rpm. I need to calculate i)the resistance to be placed in the armature circuit to limit braking current to twice the full load value, ii)the...
  3. K

    Impulse Response Function

    Hi, given the state equations of a system, x(dot) = Ax + Bu y = Cx is the impulse response function of this system C(e^(At))B? If not, how can i identify the impulse response from a given state equations? Please advise. Thank you.
  4. K

    Matlab Plot Help Needed

    i need to convert my transfer function to t-domain format and then plot the graph of the equivalent t-domain equation. i am using the ilaplace function to convert the s-domain transfer function to the t-domain equation. my code is >> f = (s + 3.1)/(s^2 +3.1*s + 2.23) f =...
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    Combine two different size matrix in state equations

    i have two sets of state equations: 1) x(dot) = (2x2)x + (2x1)u y = (1x2)x 2) x(dot) = (0)x + (1x1)u y = (1x1)x given the above, since A, B and C are of different sizes, how can i add the A from 1) and 2) to get a combined A? Is that possible? Please advise. Thank you.
  6. K

    Transfer Function

    U(s) is my input, Y(s) is the output. I have two plants, G1(s) and G2(s). Between these two plants, i have a disturbance input, D(s). Am i right to say Y(s) = U(s)G1(s)G2(s) + G2(s)D(s)? If that is the case, how can i get the overall transfer function Y(s)/U(s)? Please advise. Thank you.