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"
40 #include "FGMassBalance.h"
42 static const char *IdSrc = "$Id$";
43 static const char *IdHdr = ID_INERTIAL;
45 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
47 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
50 FGInertial::FGInertial(FGFDMExec* fgex) : FGModel(fgex)
57 RotationRate = 0.00007272205217;
59 RadiusReference = 20925650.00;
60 gAccelReference = GM/(RadiusReference*RadiusReference);
61 gAccel = GM/(RadiusReference*RadiusReference);
62 vCoriolis.InitMatrix();
63 vCentrifugal.InitMatrix();
64 vGravity.InitMatrix();
71 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
73 FGInertial::~FGInertial(void)
79 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
81 bool FGInertial::Run(void)
83 if (!FGModel::Run()) {
85 gAccel = GM / (Position->GetRadius()*Position->GetRadius());
87 vGravity(eDown) = gAccel;
89 // The following equation for vOmegaLocal terms shows the angular velocity
90 // calculation _for_the_local_frame_ given the earth's rotation (first set)
91 // at the current latitude, and also the component due to the aircraft
92 // motion over the curved surface of the earth (second set).
94 vOmegaLocal(eX) = omega() * cos(Position->GetLatitude());
95 vOmegaLocal(eY) = 0.0;
96 vOmegaLocal(eZ) = omega() * -sin(Position->GetLatitude());
98 vOmegaLocal(eX) += Position->GetVe() / Position->GetRadius();
99 vOmegaLocal(eY) += -Position->GetVn() / Position->GetRadius();
100 vOmegaLocal(eZ) += 0.00;
102 // Coriolis acceleration is normally written: -2w*dr/dt, but due to the axis
103 // conventions used here the sign is reversed: 2w*dr/dt. The same is true for
104 // Centrifugal acceleration.
106 vCoriolis(eEast) = 2.0*omega() * (Position->GetVd()*cos(Position->GetLatitude()) +
107 Position->GetVn()*sin(Position->GetLatitude()));
109 vRadius(eDown) = Position->GetRadius();
110 vCentrifugal(eDown) = -vOmegaLocal.Magnitude() * vOmegaLocal.Magnitude() * vRadius(eDown);
112 vForces = State->GetTl2b() * MassBalance->GetMass() * (vCoriolis + vCentrifugal + vGravity);
120 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
122 bool FGInertial::LoadInertial(FGConfigFile* AC_cfg)
127 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
129 void FGInertial::bind(void)
131 typedef double (FGInertial::*PMF)(int) const;
132 PropertyManager->Tie("forces/fbx-inertial-lbs", this,1,
133 (PMF)&FGInertial::GetForces);
134 PropertyManager->Tie("forces/fby-inertial-lbs", this,2,
135 (PMF)&FGInertial::GetForces);
136 PropertyManager->Tie("forces/fbz-inertial-lbs", this,3,
137 (PMF)&FGInertial::GetForces);
140 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
142 void FGInertial::unbind(void)
144 PropertyManager->Untie("forces/fbx-inertial-lbs");
145 PropertyManager->Untie("forces/fby-inertial-lbs");
146 PropertyManager->Untie("forces/fbz-inertial-lbs");
149 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
150 // The bitmasked value choices are as follows:
151 // unset: In this case (the default) JSBSim would only print
152 // out the normally expected messages, essentially echoing
153 // the config files as they are read. If the environment
154 // variable is not set, debug_lvl is set to 1 internally
155 // 0: This requests JSBSim not to output any messages
157 // 1: This value explicity requests the normal JSBSim
159 // 2: This value asks for a message to be printed out when
160 // a class is instantiated
161 // 4: When this value is set, a message is displayed when a
162 // FGModel object executes its Run() method
163 // 8: When this value is set, various runtime state variables
164 // are printed out periodically
165 // 16: When set various parameters are sanity checked and
166 // a message is printed out when they go out of bounds
168 void FGInertial::Debug(int from)
170 if (debug_lvl <= 0) return;
172 if (debug_lvl & 1) { // Standard console startup message output
173 if (from == 0) { // Constructor
177 if (debug_lvl & 2 ) { // Instantiation/Destruction notification
178 if (from == 0) cout << "Instantiated: FGInertial" << endl;
179 if (from == 1) cout << "Destroyed: FGInertial" << endl;
181 if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
183 if (debug_lvl & 8 ) { // Runtime state variables
185 if (debug_lvl & 16) { // Sanity checking
187 if (debug_lvl & 64) {
188 if (from == 0) { // Constructor
189 cout << IdSrc << endl;
190 cout << IdHdr << endl;