rss

Generate random continuous-time test model

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    Syntax

    sys = rss(n)
    sys = rss(n,p,m)
    sys = rss(n,p,m,s1,...,sk)

    Description

    sys = rss(n) generates a SISO state-space model sys of order n. The poles of sys are random and stable with the possible exception of poles at s = 0 (integrators).

    example

    sys = rss(n,p,m) generates a state-space model with p outputs and m inputs.

    example

    sys = rss(n,p,m,s1,...,sk) generates an s1-by-...-by-sn array of state-space models.

    example

    Examples

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    Open Live Script

    Generate a random SISO state-space model with two states.

    sys2 = rss(2)
    sys2 =
 
  A = 
            x1       x2
   x1  -0.8429  -0.2134
   x2  -0.5162   -1.214
 
  B = 
             u1
   x1    0.7254
   x2  -0.06305
 
  C = 
           x1      x2
   y1       0  -0.205
 
  D = 
            u1
   y1  -0.1241
 
Continuous-time state-space model.
Model Properties

    Generate a model with four states, three outputs, and two inputs. The input arguments to rss are arranged in the order states, outputs, inputs.

    sys4 = rss(4,3,2)
    sys4 =
 
  A = 
            x1       x2       x3       x4
   x1    45.92    1.332   -9.841   -18.02
   x2   -3.679  -0.8695    2.348  -0.8719
   x3     89.8   -2.097   -22.31   -28.27
   x4    79.49   -2.367   -19.69    -24.7
 
  B = 
            u1       u2
   x1        0  -0.2256
   x2    1.533        0
   x3  -0.7697        0
   x4        0  0.03256
 
  C = 
            x1       x2       x3       x4
   y1   0.5525  0.08593   -1.062   0.7481
   y2    1.101        0     2.35  -0.1924
   y3    1.544        0  -0.6156   0.8886
 
  D = 
            u1       u2
   y1        0   0.4882
   y2   -1.402        0
   y3        0  -0.1961
 
Continuous-time state-space model.
Model Properties
    Open Live Script

    Generate a 4-by-5 array of SISO models with three states each.

    sysarray = rss(3,1,1,4,5);
size(sysarray)
    4x5 array of state-space models.
Each model has 1 outputs, 1 inputs, and 3 states.

    Input Arguments

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    Model order, specified as a nonnegative integer. n determines the number of states in the generated model sys. If n=0, then sys is a static gain.

    Output and input dimensions of sys, specified as nonnegative integers.

    Example: sys = rss(5,4,3) generates a state-space model with five states, four outputs, and three inputs.

    Array dimensions of sys, specified as nonnegative integers. Specifying these values generates an k-dimensional array of state-space models where each entry in the array is a state-space model of order n with p outputs and m inputs.

    Example: sys = rss(1,1,1,2,3) generates a two-by-three array of SISO models.

    Output Arguments

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    Random state-space model, returned as a ss model or array of ss models. The poles of sys are random and stable with the possible exception of poles at s = 0 (integrators).

    Tips

    • To convert the ss model sys to transfer-function, frequency-response, or zero-pole-gain form, use tf, frd, or zpk, respectively. For example, sys = tf(rss(3)) returns a third-order SISO transfer function as a tf model object.

    Version History

    Introduced before R2006a

    See Also

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