src/FDM/JSBSim/filtersjb/FGFilter.cpp

   1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2
   3  Module:       FGFilter.cpp
   4  Author:       Jon S. Berndt
   5  Date started: 11/2000
   6
   7  ------------- Copyright (C) 2000 -------------
   8
   9  This program is free software; you can redistribute it and/or modify it under
  10  the terms of the GNU General Public License as published by the Free Software
  11  Foundation; either version 2 of the License, or (at your option) any later
  12  version.
  13
  14  This program is distributed in the hope that it will be useful, but WITHOUT
  15  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  16  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  17  details.
  18
  19  You should have received a copy of the GNU General Public License along with
  20  this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  21  Place - Suite 330, Boston, MA  02111-1307, USA.
  22
  23  Further information about the GNU General Public License can also be found on
  24  the world wide web at http://www.gnu.org.
  25
  26 FUNCTIONAL DESCRIPTION
  27 --------------------------------------------------------------------------------
  28
  29 HISTORY
  30 --------------------------------------------------------------------------------
  31
  32 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  33 COMMENTS, REFERENCES,  and NOTES
  34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  35
  36 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  37 INCLUDES
  38 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  39
  40 #include "FGFilter.h"
  41
  42 static const char *IdSrc = "$Id$";
  43 static const char *IdHdr = ID_FILTER;
  44
  45 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  46 CLASS IMPLEMENTATION
  47 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  48
  49 FGFilter::FGFilter(FGFCS* fcs, FGConfigFile* AC_cfg) : FGFCSComponent(fcs),
  50                                                        AC_cfg(AC_cfg)
  51 {
  52   string token;
  53   double denom;
  54
  55   Type = AC_cfg->GetValue("TYPE");
  56   Name = AC_cfg->GetValue("NAME");
  57   AC_cfg->GetNextConfigLine();
  58   dt = fcs->GetState()->Getdt();
  59
  60   C1 = C2 = C3 = C4 = C5 = C6 = 0.0;
  61
  62   if      (Type == "LAG_FILTER")          FilterType = eLag        ;
  63   else if (Type == "LEAD_LAG_FILTER")     FilterType = eLeadLag    ;
  64   else if (Type == "SECOND_ORDER_FILTER") FilterType = eOrder2     ;
  65   else if (Type == "WASHOUT_FILTER")      FilterType = eWashout    ;
  66   else if (Type == "INTEGRATOR")          FilterType = eIntegrator ;
  67   else                                    FilterType = eUnknown    ;
  68
  69   while ((token = AC_cfg->GetValue()) != string("/COMPONENT")) {
  70     *AC_cfg >> token;
  71     if      (token == "ID")     *AC_cfg >> ID;
  72     else if (token == "C1")     *AC_cfg >> C1;
  73     else if (token == "C2")     *AC_cfg >> C2;
  74     else if (token == "C3")     *AC_cfg >> C3;
  75     else if (token == "C4")     *AC_cfg >> C4;
  76     else if (token == "C5")     *AC_cfg >> C5;
  77     else if (token == "C6")     *AC_cfg >> C6;
  78     else if (token == "INPUT")
  79     {
  80       token = AC_cfg->GetValue("INPUT");
  81       if (token.find("FG_") != token.npos) {
  82         *AC_cfg >> token;
  83         InputIdx = fcs->GetState()->GetParameterIndex(token);
  84         InputType = itPilotAC;
  85       } else {
  86         *AC_cfg >> InputIdx;
  87         InputType = itFCS;
  88       }
  89     }
  90     else if (token == "OUTPUT")
  91     {
  92       IsOutput = true;
  93       *AC_cfg >> sOutputIdx;
  94       OutputIdx = fcs->GetState()->GetParameterIndex(sOutputIdx);
  95     }
  96     else cerr << "Unknown filter type: " << token << endl;
  97   }
  98
  99   Initialize = true;
 100
 101   switch (FilterType) {
 102     case eLag:
 103       denom = 2.00 + dt*C1;
 104       ca = dt*C1 / denom;
 105       cb = (2.00 - dt*C1) / denom;
 106       break;
 107     case eLeadLag:
 108       denom = 2.00*C3 + dt*C4;
 109       ca = (2.00*C1 + dt*C2) / denom;
 110       cb = (dt*C2 - 2.00*C1) / denom;
 111       cc = (2.00*C3 - dt*C2) / denom;
 112       break;
 113     case eOrder2:
 114       denom = 4.0*C3 + 2.0*C5*dt + C6*dt*dt;
 115       ca = 4.0*C1 + 2.0*C2*dt + C3*dt*dt / denom;
 116       cb = 2.0*C3*dt*dt - 8.0*C1 / denom;
 117       cc = 4.0*C1 - 2.0*C2*dt + C3*dt*dt / denom;
 118       cd = 2.0*C6*dt*dt - 8.0*C4 / denom;
 119       ce = 4.0*C3 - 2.0*C5*dt + C6*dt*dt / denom;
 120       break;
 121     case eWashout:
 122       denom = 2.00 + dt*C1;
 123       ca = 2.00 / denom;
 124       cb = (2.00 - dt*C1) / denom;
 125       break;
 126     case eIntegrator:
 127       ca = dt*C1 / 2.00;
 128       break;
 129     case eUnknown:
 130       cerr << "Unknown filter type" << endl;
 131     break;
 132   }
 133
 134   if (debug_lvl > 0) {
 135       cout << "      ID: " << ID << endl;
 136       cout << "      INPUT: " << InputIdx << endl;
 137       cout << "      C1: " << C1 << endl;
 138       cout << "      C2: " << C2 << endl;
 139       cout << "      C3: " << C3 << endl;
 140       cout << "      C4: " << C4 << endl;
 141       cout << "      C5: " << C5 << endl;
 142       cout << "      C6: " << C6 << endl;
 143       if (IsOutput) cout << "      OUTPUT: " << sOutputIdx << endl;
 144   }
 145
 146   if (debug_lvl & 2) cout << "Instantiated: FGFilter" << endl;
 147 }
 148
 149 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 150
 151 FGFilter::~FGFilter()
 152 {
 153   if (debug_lvl & 2) cout << "Destroyed:    FGFilter" << endl;
 154 }
 155
 156 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 157
 158 bool FGFilter::Run(void)
 159 {
 160   FGFCSComponent::Run(); // call the base class for initialization of Input
 161
 162   if (Initialize) {
 163
 164     PreviousOutput1 = PreviousInput1 = Output = Input;
 165     Initialize = false;
 166
 167   } else {
 168
 169     switch (FilterType) {
 170       case eLag:
 171         Output = Input * ca + PreviousInput1 * ca + PreviousOutput1 * cb;
 172         break;
 173       case eLeadLag:
 174         Output = Input * ca + PreviousInput1 * cb + PreviousOutput1 * cc;
 175         break;
 176       case eOrder2:
 177         Output = Input * ca + PreviousInput1 * cb + PreviousInput2 * cc
 178                                   - PreviousOutput1 * cd - PreviousOutput2 * ce;
 179         break;
 180       case eWashout:
 181         Output = Input * ca - PreviousInput1 * ca + PreviousOutput1 * cb;
 182         break;
 183       case eIntegrator:
 184         Output = Input * ca + PreviousInput1 * ca + PreviousOutput1;
 185         break;
 186     }
 187
 188   }
 189
 190   PreviousOutput2 = PreviousOutput1;
 191   PreviousOutput1 = Output;
 192   PreviousInput2  = PreviousInput1;
 193   PreviousInput1  = Input;
 194
 195   if (IsOutput) SetOutput();
 196
 197   return true;
 198 }
 199
 200 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 201
 202 void FGFilter::Debug(void)
 203 {
 204     //TODO: Add your source code here
 205 }
 206