1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3 Module: FGAuxiliary.cpp
4 Author: Tony Peden, Jon Berndt
6 Purpose: Calculates additional parameters needed by the visual system, etc.
9 ------------- Copyright (C) 1999 Jon S. Berndt (jsb@hal-pc.org) -------------
11 This program is free software; you can redistribute it and/or modify it under
12 the terms of the GNU General Public License as published by the Free Software
13 Foundation; either version 2 of the License, or (at your option) any later
16 This program is distributed in the hope that it will be useful, but WITHOUT
17 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
18 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
21 You should have received a copy of the GNU General Public License along with
22 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
23 Place - Suite 330, Boston, MA 02111-1307, USA.
25 Further information about the GNU General Public License can also be found on
26 the world wide web at http://www.gnu.org.
28 FUNCTIONAL DESCRIPTION
29 --------------------------------------------------------------------------------
30 This class calculates various auxiliary parameters.
33 Anderson, John D. "Introduction to Flight", 3rd Edition, McGraw-Hill, 1989
36 --------------------------------------------------------------------------------
39 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
41 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
43 #include "FGAuxiliary.h"
44 #include "FGAerodynamics.h"
45 #include "FGTranslation.h"
46 #include "FGRotation.h"
47 #include "FGAtmosphere.h"
49 #include "FGFDMExec.h"
51 #include "FGAircraft.h"
52 #include "FGPosition.h"
54 #include "FGInertial.h"
55 #include "FGMatrix33.h"
56 #include "FGColumnVector3.h"
57 #include "FGColumnVector4.h"
58 #include "FGPropertyManager.h"
62 static const char *IdSrc = "$Id$";
63 static const char *IdHdr = ID_AUXILIARY;
65 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
67 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
70 FGAuxiliary::FGAuxiliary(FGFDMExec* fdmex) : FGModel(fdmex)
73 vcas = veas = mach = qbar = pt = tat = 0;
77 vPilotAccelN.InitMatrix();
84 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
86 FGAuxiliary::~FGAuxiliary()
92 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
94 bool FGAuxiliary::Run()
98 if (!FGModel::Run()) {
101 //calculate total temperature assuming isentropic flow
102 tat=sat*(1 + 0.2*mach*mach);
103 tatc=RankineToCelsius(tat);
105 if (mach < 1) { //calculate total pressure assuming isentropic flow
106 pt=p*pow((1 + 0.2*machU*machU),3.5);
108 // shock in front of pitot tube, we'll assume its normal and use
109 // the Rayleigh Pitot Tube Formula, i.e. the ratio of total
110 // pressure behind the shock to the static pressure in front
112 B = 5.76*machU*machU/(5.6*machU*machU - 0.8);
114 // The denominator above is zero for Mach ~ 0.38, for which
115 // we'll never be here, so we're safe
117 D = (2.8*machU*machU-0.4)*0.4167;
121 A = pow(((pt-p)/psl+1),0.28571);
123 vcas = sqrt(7*psl/rhosl*(A-1));
124 veas = sqrt(2*qbar/rhosl);
129 // Pilot sensed accelerations are calculated here. This is used
130 // for the coordinated turn ball instrument. Motion base platforms sometimes
131 // use the derivative of pilot sensed accelerations as the driving parameter,
132 // rather than straight accelerations.
134 // The theory behind pilot-sensed calculations is presented:
136 // For purposes of discussion and calculation, assume for a minute that the
137 // pilot is in space and motionless in inertial space. She will feel
138 // no accelerations. If the aircraft begins to accelerate along any axis or
139 // axes (without rotating), the pilot will sense those accelerations. If
140 // any rotational moment is applied, the pilot will sense an acceleration
141 // due to that motion in the amount:
143 // [wdot X R] + [w X (w X R)]
148 // wdot = omegadot, the rotational acceleration rate vector
149 // w = omega, the rotational rate vector
150 // R = the vector from the aircraft CG to the pilot eyepoint
152 // The sum total of these two terms plus the acceleration of the aircraft
153 // body axis gives the acceleration the pilot senses in inertial space.
154 // In the presence of a large body such as a planet, a gravity field also
155 // provides an accelerating attraction. This acceleration can be transformed
156 // from the reference frame of the planet so as to be expressed in the frame
157 // of reference of the aircraft. This gravity field accelerating attraction
158 // is felt by the pilot as a force on her tushie as she sits in her aircraft
159 // on the runway awaiting takeoff clearance.
161 // In JSBSim the acceleration of the body frame in inertial space is given
162 // by the F = ma relation. If the vForces vector is divided by the aircraft
163 // mass, the acceleration vector is calculated. The term wdot is equivalent
164 // to the JSBSim vPQRdot vector, and the w parameter is equivalent to vPQR.
165 // The radius R is calculated below in the vector vToEyePt.
167 vPilotAccel.InitMatrix();
168 if ( Translation->GetVt() > 1 ) {
169 vPilotAccel = Aerodynamics->GetForces()
170 + Propulsion->GetForces()
171 + GroundReactions->GetForces();
172 vPilotAccel /= MassBalance->GetMass();
173 vToEyePt = Aircraft->GetXYZep() - MassBalance->GetXYZcg();
174 vToEyePt *= inchtoft;
175 vPilotAccel += Rotation->GetPQRdot() * vToEyePt;
176 vPilotAccel += Rotation->GetPQR() * (Rotation->GetPQR() * vToEyePt);
178 vPilotAccel = -1*( State->GetTl2b() * Inertial->GetGravity() );
181 vPilotAccelN = vPilotAccel/Inertial->gravity();
184 earthPosAngle += State->Getdt()*Inertial->omega();
191 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
193 double FGAuxiliary::GetHeadWind(void)
197 psiw = Atmosphere->GetWindPsi();
198 psi = Rotation->Getpsi();
199 vw = Atmosphere->GetWindNED().Magnitude();
201 return vw*cos(psiw - psi);
204 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
206 double FGAuxiliary::GetCrossWind(void)
210 psiw = Atmosphere->GetWindPsi();
211 psi = Rotation->Getpsi();
212 vw = Atmosphere->GetWindNED().Magnitude();
214 return vw*sin(psiw - psi);
217 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
219 void FGAuxiliary::bind(void)
221 typedef double (FGAuxiliary::*PMF)(int) const;
222 PropertyManager->Tie("velocities/vc-fps", this,
223 &FGAuxiliary::GetVcalibratedFPS);
224 PropertyManager->Tie("velocities/vc-kts", this,
225 &FGAuxiliary::GetVcalibratedKTS);
226 PropertyManager->Tie("velocities/ve-fps", this,
227 &FGAuxiliary::GetVequivalentFPS);
228 PropertyManager->Tie("velocities/ve-kts", this,
229 &FGAuxiliary::GetVequivalentKTS);
230 PropertyManager->Tie("velocities/machU", this,
231 &FGAuxiliary::GetMachU);
232 PropertyManager->Tie("velocities/tat-r", this,
233 &FGAuxiliary::GetTotalTemperature);
234 PropertyManager->Tie("velocities/tat-c", this,
235 &FGAuxiliary::GetTAT_C);
236 PropertyManager->Tie("velocities/pt-lbs_sqft", this,
237 &FGAuxiliary::GetTotalPressure);
239 PropertyManager->Tie("accelerations/a-pilot-x-ft_sec2", this,1,
240 (PMF)&FGAuxiliary::GetPilotAccel);
241 PropertyManager->Tie("accelerations/a-pilot-y-ft_sec2", this,2,
242 (PMF)&FGAuxiliary::GetPilotAccel);
243 PropertyManager->Tie("accelerations/a-pilot-z-ft_sec2", this,3,
244 (PMF)&FGAuxiliary::GetPilotAccel);
245 PropertyManager->Tie("accelerations/n-pilot-x-norm", this,1,
246 (PMF)&FGAuxiliary::GetNpilot);
247 PropertyManager->Tie("accelerations/n-pilot-y-norm", this,2,
248 (PMF)&FGAuxiliary::GetNpilot);
249 PropertyManager->Tie("accelerations/n-pilot-z-norm", this,3,
250 (PMF)&FGAuxiliary::GetNpilot);
251 PropertyManager->Tie("position/epa-rad", this,
252 &FGAuxiliary::GetEarthPositionAngle);
253 /* PropertyManager->Tie("atmosphere/headwind-fps", this,
254 &FGAuxiliary::GetHeadWind,
256 PropertyManager->Tie("atmosphere/crosswind-fps", this,
257 &FGAuxiliary::GetCrossWind,
261 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
263 void FGAuxiliary::unbind(void)
265 PropertyManager->Untie("velocities/vc-fps");
266 PropertyManager->Untie("velocities/vc-kts");
267 PropertyManager->Untie("velocities/ve-fps");
268 PropertyManager->Untie("velocities/ve-kts");
269 PropertyManager->Untie("velocities/machU");
270 PropertyManager->Untie("velocities/tat-r");
271 PropertyManager->Untie("velocities/tat-c");
272 PropertyManager->Untie("accelerations/a-pilot-x-ft_sec2");
273 PropertyManager->Untie("accelerations/a-pilot-y-ft_sec2");
274 PropertyManager->Untie("accelerations/a-pilot-z-ft_sec2");
275 PropertyManager->Untie("accelerations/n-pilot-x-norm");
276 PropertyManager->Untie("accelerations/n-pilot-y-norm");
277 PropertyManager->Untie("accelerations/n-pilot-z-norm");
278 PropertyManager->Untie("position/epa-rad");
279 /* PropertyManager->Untie("atmosphere/headwind-fps");
280 PropertyManager->Untie("atmosphere/crosswind-fps"); */
284 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
286 void FGAuxiliary::GetState(void)
288 qbar = Translation->Getqbar();
289 mach = Translation->GetMach();
290 machU= Translation->GetMachU();
291 p = Atmosphere->GetPressure();
292 rhosl = Atmosphere->GetDensitySL();
293 psl = Atmosphere->GetPressureSL();
294 sat = Atmosphere->GetTemperature();
297 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
298 // The bitmasked value choices are as follows:
299 // unset: In this case (the default) JSBSim would only print
300 // out the normally expected messages, essentially echoing
301 // the config files as they are read. If the environment
302 // variable is not set, debug_lvl is set to 1 internally
303 // 0: This requests JSBSim not to output any messages
305 // 1: This value explicity requests the normal JSBSim
307 // 2: This value asks for a message to be printed out when
308 // a class is instantiated
309 // 4: When this value is set, a message is displayed when a
310 // FGModel object executes its Run() method
311 // 8: When this value is set, various runtime state variables
312 // are printed out periodically
313 // 16: When set various parameters are sanity checked and
314 // a message is printed out when they go out of bounds
316 void FGAuxiliary::Debug(int from)
318 if (debug_lvl <= 0) return;
320 if (debug_lvl & 1) { // Standard console startup message output
321 if (from == 0) { // Constructor
325 if (debug_lvl & 2 ) { // Instantiation/Destruction notification
326 if (from == 0) cout << "Instantiated: FGAuxiliary" << endl;
327 if (from == 1) cout << "Destroyed: FGAuxiliary" << endl;
329 if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
331 if (debug_lvl & 8 ) { // Runtime state variables
333 if (debug_lvl & 16) { // Sanity checking
335 if (debug_lvl & 64) {
336 if (from == 0) { // Constructor
337 cout << IdSrc << endl;
338 cout << IdHdr << endl;
343 } // namespace JSBSim