-/*******************************************************************************
-
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
Module: FGAuxiliary.cpp
- Author: Jon Berndt
+ Author: Tony Peden, Jon Berndt
Date started: 01/26/99
Purpose: Calculates additional parameters needed by the visual system, etc.
Called by: FGSimExec
-
+
------------- Copyright (C) 1999 Jon S. Berndt (jsb@hal-pc.org) -------------
-
+
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.
-
+
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
FUNCTIONAL DESCRIPTION
--------------------------------------------------------------------------------
-This class calculates various auxiliary parameters, mostly used by the visual
-system
+This class calculates various auxiliary parameters.
+REFERENCES
+ Anderson, John D. "Introduction to Flight", 3rd Edition, McGraw-Hill, 1989
+ pgs. 112-126
HISTORY
--------------------------------------------------------------------------------
01/26/99 JSB Created
-********************************************************************************
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
-*******************************************************************************/
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
#include "FGAuxiliary.h"
#include "FGTranslation.h"
#include "FGAircraft.h"
#include "FGPosition.h"
#include "FGOutput.h"
+#include "FGInertial.h"
+#include "FGMatrix33.h"
+#include "FGColumnVector3.h"
+#include "FGColumnVector4.h"
+#include "FGPropertyManager.h"
+
+static const char *IdSrc = "$Id$";
+static const char *IdHdr = ID_AUXILIARY;
+
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+CLASS IMPLEMENTATION
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-/*******************************************************************************
-************************************ CODE **************************************
-*******************************************************************************/
FGAuxiliary::FGAuxiliary(FGFDMExec* fdmex) : FGModel(fdmex)
{
Name = "FGAuxiliary";
+ vcas = veas = mach = qbar = pt = 0;
+ psl = rhosl = 1;
+ earthPosAngle = 0.0;
+
+ vPilotAccelN.InitMatrix();
+
+ Debug(0);
}
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FGAuxiliary::~FGAuxiliary()
{
+ Debug(1);
}
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
bool FGAuxiliary::Run()
{
+ double A,B,D;
+
if (!FGModel::Run()) {
+ GetState();
+ if (mach < 1) { //calculate total pressure assuming isentropic flow
+ pt=p*pow((1 + 0.2*mach*mach),3.5);
+ } else {
+ // shock in front of pitot tube, we'll assume its normal and use
+ // the Rayleigh Pitot Tube Formula, i.e. the ratio of total
+ // pressure behind the shock to the static pressure in front
+
+ B = 5.76*mach*mach/(5.6*mach*mach - 0.8);
+
+ // The denominator above is zero for Mach ~ 0.38, for which
+ // we'll never be here, so we're safe
+
+ D = (2.8*mach*mach-0.4)*0.4167;
+ pt = p*pow(B,3.5)*D;
+ }
+
+ A = pow(((pt-p)/psl+1),0.28571);
+ vcas = sqrt(7*psl/rhosl*(A-1));
+ veas = sqrt(2*qbar/rhosl);
+
+ // Pilot sensed accelerations are calculated here. This is used
+ // for the coordinated turn ball instrument. Motion base platforms sometimes
+ // use the derivative of pilot sensed accelerations as the driving parameter,
+ // rather than straight accelerations.
+ //
+ // The theory behind pilot-sensed calculations is presented:
+ //
+ // For purposes of discussion and calculation, assume for a minute that the
+ // pilot is in space and motionless in inertial space. She will feel
+ // no accelerations. If the aircraft begins to accelerate along any axis or
+ // axes (without rotating), the pilot will sense those accelerations. If
+ // any rotational moment is applied, the pilot will sense an acceleration
+ // due to that motion in the amount:
+ //
+ // [wdot X R] + [w X (w X R)]
+ // Term I Term II
+ //
+ // where:
+ //
+ // wdot = omegadot, the rotational acceleration rate vector
+ // w = omega, the rotational rate vector
+ // R = the vector from the aircraft CG to the pilot eyepoint
+ //
+ // The sum total of these two terms plus the acceleration of the aircraft
+ // body axis gives the acceleration the pilot senses in inertial space.
+ // In the presence of a large body such as a planet, a gravity field also
+ // provides an accelerating attraction. This acceleration can be transformed
+ // from the reference frame of the planet so as to be expressed in the frame
+ // of reference of the aircraft. This gravity field accelerating attraction
+ // is felt by the pilot as a force on her tushie as she sits in her aircraft
+ // on the runway awaiting takeoff clearance.
+ //
+ // In JSBSim the acceleration of the body frame in inertial space is given
+ // by the F = ma relation. If the vForces vector is divided by the aircraft
+ // mass, the acceleration vector is calculated. The term wdot is equivalent
+ // to the JSBSim vPQRdot vector, and the w parameter is equivalent to vPQR.
+ // The radius R is calculated below in the vector vToEyePt.
+
+ vPilotAccel.InitMatrix();
+ if ( Translation->GetVt() > 1 ) {
+ vToEyePt = Aircraft->GetXYZep() - MassBalance->GetXYZcg();
+ vToEyePt *= inchtoft;
+ vPilotAccel = Aerodynamics->GetForces()
+ + Propulsion->GetForces()
+ + GroundReactions->GetForces();
+ vPilotAccel /= MassBalance->GetMass();
+ vPilotAccel += Rotation->GetPQRdot() * vToEyePt;
+ vPilotAccel += Rotation->GetPQR() * (Rotation->GetPQR() * vToEyePt);
+ //vPilotAccel(2)*=-1;
+ vPilotAccelN = vPilotAccel/Inertial->gravity();
+ }
+ earthPosAngle += State->Getdt()*Inertial->omega();
+ return false;
} else {
+ return true;
}
- return false;
}
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGAuxiliary::GetHeadWind(void)
+{
+ double psiw,vw,psi;
+
+ psiw = Atmosphere->GetWindPsi();
+ psi = Rotation->Getpsi();
+ vw = Atmosphere->GetWindNED().Magnitude();
+
+ return vw*cos(psiw - psi);
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGAuxiliary::GetCrossWind(void)
+{
+ double psiw,vw,psi;
+
+ psiw = Atmosphere->GetWindPsi();
+ psi = Rotation->Getpsi();
+ vw = Atmosphere->GetWindNED().Magnitude();
+
+ return vw*sin(psiw - psi);
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGAuxiliary::bind(void)
+{
+ typedef double (FGAuxiliary::*PMF)(int) const;
+ PropertyManager->Tie("velocities/vc-fps", this,
+ &FGAuxiliary::GetVcalibratedFPS);
+ PropertyManager->Tie("velocities/vc-kts", this,
+ &FGAuxiliary::GetVcalibratedKTS);
+ PropertyManager->Tie("velocities/ve-fps", this,
+ &FGAuxiliary::GetVequivalentFPS);
+ PropertyManager->Tie("velocities/ve-kts", this,
+ &FGAuxiliary::GetVequivalentKTS);
+ PropertyManager->Tie("accelerations/a-pilot-x-ft_sec2", this,1,
+ (PMF)&FGAuxiliary::GetPilotAccel);
+ PropertyManager->Tie("accelerations/a-pilot-y-ft_sec2", this,2,
+ (PMF)&FGAuxiliary::GetPilotAccel);
+ PropertyManager->Tie("accelerations/a-pilot-z-ft_sec2", this,3,
+ (PMF)&FGAuxiliary::GetPilotAccel);
+ PropertyManager->Tie("accelerations/n-pilot-x-norm", this,1,
+ (PMF)&FGAuxiliary::GetNpilot);
+ PropertyManager->Tie("accelerations/n-pilot-y-norm", this,2,
+ (PMF)&FGAuxiliary::GetNpilot);
+ PropertyManager->Tie("accelerations/n-pilot-z-norm", this,3,
+ (PMF)&FGAuxiliary::GetNpilot);
+ PropertyManager->Tie("position/epa-rad", this,
+ &FGAuxiliary::GetEarthPositionAngle);
+ /* PropertyManager->Tie("atmosphere/headwind-fps", this,
+ &FGAuxiliary::GetHeadWind,
+ true);
+ PropertyManager->Tie("atmosphere/crosswind-fps", this,
+ &FGAuxiliary::GetCrossWind,
+ true); */
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGAuxiliary::unbind(void)
+{
+ PropertyManager->Untie("velocities/vc-fps");
+ PropertyManager->Untie("velocities/vc-kts");
+ PropertyManager->Untie("velocities/ve-fps");
+ PropertyManager->Untie("velocities/ve-kts");
+ PropertyManager->Untie("accelerations/a-pilot-x-ft_sec2");
+ PropertyManager->Untie("accelerations/a-pilot-y-ft_sec2");
+ PropertyManager->Untie("accelerations/a-pilot-z-ft_sec2");
+ PropertyManager->Untie("accelerations/n-pilot-x-norm");
+ PropertyManager->Untie("accelerations/n-pilot-y-norm");
+ PropertyManager->Untie("accelerations/n-pilot-z-norm");
+ PropertyManager->Untie("position/epa-rad");
+ /* PropertyManager->Untie("atmosphere/headwind-fps");
+ PropertyManager->Untie("atmosphere/crosswind-fps"); */
+
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGAuxiliary::GetState(void)
+{
+ qbar = Translation->Getqbar();
+ mach = Translation->GetMach();
+ p = Atmosphere->GetPressure();
+ rhosl = Atmosphere->GetDensitySL();
+ psl = Atmosphere->GetPressureSL();
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// The bitmasked value choices are as follows:
+// unset: In this case (the default) JSBSim would only print
+// out the normally expected messages, essentially echoing
+// the config files as they are read. If the environment
+// variable is not set, debug_lvl is set to 1 internally
+// 0: This requests JSBSim not to output any messages
+// whatsoever.
+// 1: This value explicity requests the normal JSBSim
+// startup messages
+// 2: This value asks for a message to be printed out when
+// a class is instantiated
+// 4: When this value is set, a message is displayed when a
+// FGModel object executes its Run() method
+// 8: When this value is set, various runtime state variables
+// are printed out periodically
+// 16: When set various parameters are sanity checked and
+// a message is printed out when they go out of bounds
+
+void FGAuxiliary::Debug(int from)
+{
+ if (debug_lvl <= 0) return;
+
+ if (debug_lvl & 1) { // Standard console startup message output
+ if (from == 0) { // Constructor
+
+ }
+ }
+ if (debug_lvl & 2 ) { // Instantiation/Destruction notification
+ if (from == 0) cout << "Instantiated: FGAuxiliary" << endl;
+ if (from == 1) cout << "Destroyed: FGAuxiliary" << endl;
+ }
+ if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
+ }
+ if (debug_lvl & 8 ) { // Runtime state variables
+ }
+ if (debug_lvl & 16) { // Sanity checking
+ }
+ if (debug_lvl & 64) {
+ if (from == 0) { // Constructor
+ cout << IdSrc << endl;
+ cout << IdHdr << endl;
+ }
+ }
+}
projects / flightgear.git / blobdiff