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1 ## Copyright (C) 1997, 2000, 2004, 2005, 2006, 2007 Kai P. Mueller |
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2 ## |
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3 ## This file is part of Octave. |
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4 ## |
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5 ## Octave is free software; you can redistribute it and/or modify it |
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6 ## under the terms of the GNU General Public License as published by |
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7 ## the Free Software Foundation; either version 3 of the License, or (at |
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8 ## your option) any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License for more details. |
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14 ## |
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15 ## You should have received a copy of the GNU General Public License |
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16 ## along with Octave; see the file COPYING. If not, see |
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17 ## <http://www.gnu.org/licenses/>. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Function File} {} ord2 (@var{nfreq}, @var{damp}, @var{gain}) |
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21 ## Creates a continuous 2nd order system with parameters: |
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22 ## |
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23 ## @strong{Inputs} |
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24 ## @table @var |
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25 ## @item nfreq |
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26 ## natural frequency [Hz]. (not in rad/s) |
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27 ## @item damp |
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28 ## damping coefficient |
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29 ## @item gain |
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30 ## dc-gain |
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31 ## This is steady state value only for damp > 0. |
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32 ## gain is assumed to be 1.0 if omitted. |
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33 ## @end table |
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34 ## |
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35 ## @strong{Output} |
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36 ## @table @var |
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37 ## @item outsys |
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38 ## system data structure has representation with |
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39 ## @ifinfo |
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40 ## @math{w = 2 * pi * nfreq}: |
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41 ## @end ifinfo |
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42 ## @iftex |
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43 ## @tex |
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44 ## $ w = 2 \pi f $: |
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45 ## @end tex |
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46 ## @end iftex |
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47 ## @example |
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48 ## @group |
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49 ## / \ |
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50 ## | / -2w*damp -w \ / w \ | |
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51 ## G = | | |, | |, [ 0 gain ], 0 | |
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52 ## | \ w 0 / \ 0 / | |
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53 ## \ / |
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54 ## @end group |
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55 ## @end example |
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56 ## @end table |
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57 ## @strong{See also} @command{jet707} (@acronym{MIMO} example, Boeing 707-321 |
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58 ## aircraft model) |
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59 ## @end deftypefn |
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60 |
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61 ## Author: Kai P. Mueller <mueller@ifr.ing.tu-bs.de> |
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62 ## Created: September 28, 1997 |
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63 |
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64 function outsys = ord2 (nfreq, damp, gain) |
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65 |
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66 ## Updates |
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67 |
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68 if (nargin == 2 || nargin == 3) |
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69 if (nargin == 2) |
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70 gain = 1.0; |
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71 endif |
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72 w = 2.0 * pi * nfreq; |
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73 outsys = ss ([-2.0*w*damp, -w; w, 0], [w; 0], [0, gain]); |
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74 else |
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75 print_usage (); |
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76 endif |
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77 |
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78 endfunction |
