src/FDM/JSBSim/FGInertial.cpp

   1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2
   3  Module:       FGInertial.cpp
   4  Author:       Jon S. Berndt
   5  Date started: 09/13/00
   6  Purpose:      Encapsulates the inertial frame forces (coriolis and centrifugal)
   7
   8  ------------- Copyright (C) 2000  Jon S. Berndt (jsb@hal-pc.org) -------------
   9
  10  This program is free software; you can redistribute it and/or modify it under
  11  the terms of the GNU General Public License as published by the Free Software
  12  Foundation; either version 2 of the License, or (at your option) any later
  13  version.
  14
  15  This program is distributed in the hope that it will be useful, but WITHOUT
  16  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  17  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  18  details.
  19
  20  You should have received a copy of the GNU General Public License along with
  21  this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  22  Place - Suite 330, Boston, MA  02111-1307, USA.
  23
  24  Further information about the GNU General Public License can also be found on
  25  the world wide web at http://www.gnu.org.
  26
  27 FUNCTIONAL DESCRIPTION
  28 --------------------------------------------------------------------------------
  29
  30 HISTORY
  31 --------------------------------------------------------------------------------
  32 09/13/00   JSB   Created
  33
  34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  35 INCLUDES
  36 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  37
  38 #include "FGInertial.h"
  39 #include "FGPosition.h"
  40 #include "FGMassBalance.h"
  41
  42 static const char *IdSrc = "$Id$";
  43 static const char *IdHdr = ID_INERTIAL;
  44
  45 extern short debug_lvl;
  46
  47 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  48 CLASS IMPLEMENTATION
  49 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  50
  51
  52 FGInertial::FGInertial(FGFDMExec* fgex) : FGModel(fgex),
  53     vForces(3),
  54     vOmegaLocal(3),
  55     vRadius(3)
  56 {
  57   Name = "FGInertial";
  58
  59   vRadius.InitMatrix();
  60
  61   if (debug_lvl & 2) cout << "Instantiated: FGInertial" << endl;
  62 }
  63
  64 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  65
  66 FGInertial::~FGInertial(void)
  67 {
  68   if (debug_lvl & 2) cout << "Destroyed:    FGInertial" << endl;
  69 }
  70
  71 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  72
  73 bool FGInertial::Run(void)
  74 {
  75   float stht, ctht, sphi, cphi;
  76
  77   if (!FGModel::Run()) {
  78
  79     stht = sin(Rotation->GetEuler(eTht));
  80     ctht = cos(Rotation->GetEuler(eTht));
  81     sphi = sin(Rotation->GetEuler(ePhi));
  82     cphi = cos(Rotation->GetEuler(ePhi));
  83
  84     vForces(eX) = -GRAVITY*stht;
  85     vForces(eY) =  GRAVITY*sphi*ctht;
  86     vForces(eZ) =  GRAVITY*cphi*ctht;
  87
  88     // The following equation for vOmegaLocal terms shows the angular velocity
  89     // calculation _for_the_local_frame_ given the earth's rotation (first set)
  90     // at the current latitude, and also the component due to the aircraft
  91     // motion over the curved surface of the earth (second set).
  92
  93     vOmegaLocal(eX) = OMEGA_EARTH * cos(Position->GetLatitude());
  94     vOmegaLocal(eY) = 0.0;
  95     vOmegaLocal(eZ) = OMEGA_EARTH * -sin(Position->GetLatitude());
  96
  97     vOmegaLocal(eX) +=  Position->GetVe() / Position->GetRadius();
  98     vOmegaLocal(eY) += -Position->GetVn() / Position->GetRadius();
  99     vOmegaLocal(eZ) +=  0.00;
 100
 101 //    vForces = State->GetTl2b()*(-2.0*vOmegaLocal * Position->GetVel());
 102
 103     vRadius(3) = Position->GetRadius();
 104     vForces += State->GetTl2b()*(vOmegaLocal * (vOmegaLocal * vRadius));
 105
 106     vForces *= MassBalance->GetMass(); // IMPORTANT !!!!!!!!!!!!!!!!!!!!!!!!!!!!
 107
 108     return false;
 109   } else {
 110     return true;
 111   }
 112 }
 113
 114 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 115
 116 bool FGInertial::LoadInertial(FGConfigFile* AC_cfg)
 117 {
 118   return true;
 119 }
 120
 121 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 122
 123 void FGInertial::Debug(void)
 124 {
 125     //TODO: Add your source code here
 126 }
 127