1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
6 Purpose: Encapsulates the inertial frame forces (coriolis and centrifugal)
8 ------------- Copyright (C) 2000 Jon S. Berndt (jsb@hal-pc.org) -------------
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
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
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.
24 Further information about the GNU General Public License can also be found on
25 the world wide web at http://www.gnu.org.
27 FUNCTIONAL DESCRIPTION
28 --------------------------------------------------------------------------------
31 --------------------------------------------------------------------------------
34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
36 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
38 #include "FGInertial.h"
39 #include "FGPosition.h"
41 #include "FGMassBalance.h"
45 static const char *IdSrc = "$Id$";
46 static const char *IdHdr = ID_INERTIAL;
48 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
50 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
53 FGInertial::FGInertial(FGFDMExec* fgex) : FGModel(fgex)
58 RotationRate = 0.00007272205217;
60 RadiusReference = 20925650.00;
61 gAccelReference = GM/(RadiusReference*RadiusReference);
62 gAccel = GM/(RadiusReference*RadiusReference);
64 vCoriolis.InitMatrix();
65 vCentrifugal.InitMatrix();
66 vGravity.InitMatrix();
73 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
75 FGInertial::~FGInertial(void)
81 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
83 bool FGInertial::Run(void)
85 if (!FGModel::Run()) {
87 gAccel = GM / (Position->GetRadius()*Position->GetRadius());
89 vGravity(eDown) = gAccel;
91 // The following equation for vOmegaLocal terms shows the angular velocity
92 // calculation _for_the_local_frame_ given the earth's rotation (first set)
93 // at the current latitude, and also the component due to the aircraft
94 // motion over the curved surface of the earth (second set).
96 vOmegaLocal(eX) = omega() * cos(Position->GetLatitude());
97 vOmegaLocal(eY) = 0.0;
98 vOmegaLocal(eZ) = omega() * -sin(Position->GetLatitude());
100 vOmegaLocal(eX) += Position->GetVe() / Position->GetRadius();
101 vOmegaLocal(eY) += -Position->GetVn() / Position->GetRadius();
102 vOmegaLocal(eZ) += 0.00;
104 // Coriolis acceleration is normally written: -2w*dr/dt, but due to the axis
105 // conventions used here the sign is reversed: 2w*dr/dt. The same is true for
106 // Centrifugal acceleration.
108 vCoriolis(eEast) = 2.0*omega() * (Position->GetVd()*cos(Position->GetLatitude()) +
109 Position->GetVn()*sin(Position->GetLatitude()));
111 vRadius(eDown) = Position->GetRadius();
112 vCentrifugal(eDown) = -vOmegaLocal.Magnitude() * vOmegaLocal.Magnitude() * vRadius(eDown);
114 // vForces = State->GetTl2b() * MassBalance->GetMass() * (vCoriolis + vCentrifugal + vGravity);
115 vForces = State->GetTl2b() * MassBalance->GetMass() * vGravity;
123 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
125 bool FGInertial::LoadInertial(FGConfigFile* AC_cfg)
130 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
132 void FGInertial::bind(void)
134 typedef double (FGInertial::*PMF)(int) const;
135 PropertyManager->Tie("forces/fbx-inertial-lbs", this,1,
136 (PMF)&FGInertial::GetForces);
137 PropertyManager->Tie("forces/fby-inertial-lbs", this,2,
138 (PMF)&FGInertial::GetForces);
139 PropertyManager->Tie("forces/fbz-inertial-lbs", this,3,
140 (PMF)&FGInertial::GetForces);
143 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
145 void FGInertial::unbind(void)
147 PropertyManager->Untie("forces/fbx-inertial-lbs");
148 PropertyManager->Untie("forces/fby-inertial-lbs");
149 PropertyManager->Untie("forces/fbz-inertial-lbs");
152 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
153 // The bitmasked value choices are as follows:
154 // unset: In this case (the default) JSBSim would only print
155 // out the normally expected messages, essentially echoing
156 // the config files as they are read. If the environment
157 // variable is not set, debug_lvl is set to 1 internally
158 // 0: This requests JSBSim not to output any messages
160 // 1: This value explicity requests the normal JSBSim
162 // 2: This value asks for a message to be printed out when
163 // a class is instantiated
164 // 4: When this value is set, a message is displayed when a
165 // FGModel object executes its Run() method
166 // 8: When this value is set, various runtime state variables
167 // are printed out periodically
168 // 16: When set various parameters are sanity checked and
169 // a message is printed out when they go out of bounds
171 void FGInertial::Debug(int from)
173 if (debug_lvl <= 0) return;
175 if (debug_lvl & 1) { // Standard console startup message output
176 if (from == 0) { // Constructor
180 if (debug_lvl & 2 ) { // Instantiation/Destruction notification
181 if (from == 0) cout << "Instantiated: FGInertial" << endl;
182 if (from == 1) cout << "Destroyed: FGInertial" << endl;
184 if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
186 if (debug_lvl & 8 ) { // Runtime state variables
188 if (debug_lvl & 16) { // Sanity checking
190 if (debug_lvl & 64) {
191 if (from == 0) { // Constructor
192 cout << IdSrc << endl;
193 cout << IdHdr << endl;