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flightgear/src/FDM/JSBSim/FGTrimAxis.cpp
curt d19ef5cd99 Synced with latest JSBSim cvs.
2001-11-20 22:34:24 +00:00

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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Header: FGTrimAxis.cpp
Author: Tony Peden
Date started: 7/3/00
--------- Copyright (C) 1999 Anthony K. Peden (apeden@earthlink.net) ---------
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
details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA.
Further information about the GNU General Public License can also be found on
the world wide web at http://www.gnu.org.
HISTORY
--------------------------------------------------------------------------------
7/3/00 TP Created
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
#include <string>
#include <stdlib.h>
#include "FGFDMExec.h"
#include "FGAtmosphere.h"
#include "FGInitialCondition.h"
#include "FGTrimAxis.h"
#include "FGAircraft.h"
#include "FGPropulsion.h"
static const char *IdSrc = "$Id$";
static const char *IdHdr = ID_TRIMAXIS;
/*****************************************************************************/
FGTrimAxis::FGTrimAxis(FGFDMExec* fdex, FGInitialCondition* ic, State st,
Control ctrl) {
fdmex=fdex;
fgic=ic;
state=st;
control=ctrl;
max_iterations=10;
control_value=0;
its_to_stable_value=0;
total_iterations=0;
total_stability_iterations=0;
state_convert=1.0;
control_convert=1.0;
state_value=0;
switch(state) {
case tUdot: tolerance = DEFAULT_TOLERANCE; break;
case tVdot: tolerance = DEFAULT_TOLERANCE; break;
case tWdot: tolerance = DEFAULT_TOLERANCE; break;
case tQdot: tolerance = DEFAULT_TOLERANCE / 10; break;
case tPdot: tolerance = DEFAULT_TOLERANCE / 10; break;
case tRdot: tolerance = DEFAULT_TOLERANCE / 10; break;
case tHmgt: tolerance = 0.01; break;
}
solver_eps=tolerance;
switch(control) {
case tThrottle:
control_min=0;
control_max=1;
control_value=0.5;
break;
case tBeta:
control_min=-30*degtorad;
control_max=30*degtorad;
control_convert=radtodeg;
break;
case tAlpha:
control_min=fdmex->GetAircraft()->GetAlphaCLMin();
control_max=fdmex->GetAircraft()->GetAlphaCLMax();
if(control_max <= control_min) {
control_max=20*degtorad;
control_min=-5*degtorad;
}
control_value= (control_min+control_max)/2;
control_convert=radtodeg;
solver_eps=tolerance/100;
break;
case tPitchTrim:
case tElevator:
case tRollTrim:
case tAileron:
case tYawTrim:
case tRudder:
control_min=-1;
control_max=1;
state_convert=radtodeg;
solver_eps=tolerance/100;
break;
case tAltAGL:
control_min=0;
control_max=30;
control_value=fdmex->GetPosition()->GetDistanceAGL();
solver_eps=tolerance/100;
break;
case tTheta:
control_min=fdmex->GetRotation()->Gettht() - 5*degtorad;
control_max=fdmex->GetRotation()->Gettht() + 5*degtorad;
state_convert=radtodeg;
break;
case tPhi:
control_min=fdmex->GetRotation()->Getphi() - 30*degtorad;
control_max=fdmex->GetRotation()->Getphi() + 30*degtorad;
state_convert=radtodeg;
control_convert=radtodeg;
break;
case tGamma:
solver_eps=tolerance/100;
control_min=-80*degtorad;
control_max=80*degtorad;
control_convert=radtodeg;
break;
case tHeading:
control_min=fdmex->GetRotation()->Getpsi() - 30*degtorad;
control_max=fdmex->GetRotation()->Getpsi() + 30*degtorad;
state_convert=radtodeg;
break;
}
if (debug_lvl & 2) cout << "Instantiated: FGTrimAxis" << endl;
}
/*****************************************************************************/
FGTrimAxis::~FGTrimAxis()
{
if (debug_lvl & 2) cout << "Destroyed: FGTrimAxis" << endl;
}
/*****************************************************************************/
void FGTrimAxis::getState(void) {
switch(state) {
case tUdot: state_value=fdmex->GetAircraft()->GetBodyAccel()(1); break;
case tVdot: state_value=fdmex->GetAircraft()->GetBodyAccel()(2); break;
case tWdot: state_value=fdmex->GetAircraft()->GetBodyAccel()(3); break;
case tQdot: state_value=fdmex->GetRotation()->GetPQRdot(2);break;
case tPdot: state_value=fdmex->GetRotation()->GetPQRdot(1); break;
case tRdot: state_value=fdmex->GetRotation()->GetPQRdot(3); break;
case tHmgt: state_value=computeHmgt(); break;
}
}
/*****************************************************************************/
//States are not settable
void FGTrimAxis::getControl(void) {
switch(control) {
case tThrottle: control_value=fdmex->GetFCS()->GetThrottleCmd(0); break;
case tBeta: control_value=fdmex->GetTranslation()->Getalpha(); break;
case tAlpha: control_value=fdmex->GetTranslation()->Getbeta(); break;
case tPitchTrim: control_value=fdmex->GetFCS() -> GetPitchTrimCmd(); break;
case tElevator: control_value=fdmex->GetFCS() -> GetDeCmd(); break;
case tRollTrim:
case tAileron: control_value=fdmex->GetFCS() -> GetDaCmd(); break;
case tYawTrim:
case tRudder: control_value=fdmex->GetFCS() -> GetDrCmd(); break;
case tAltAGL: control_value=fdmex->GetPosition()->GetDistanceAGL();break;
case tTheta: control_value=fdmex->GetRotation()->Gettht(); break;
case tPhi: control_value=fdmex->GetRotation()->Getphi(); break;
case tGamma: control_value=fdmex->GetPosition()->GetGamma();break;
case tHeading: control_value=fdmex->GetRotation()->Getpsi(); break;
}
}
/*****************************************************************************/
double FGTrimAxis::computeHmgt(void) {
double diff;
diff = fdmex->GetRotation()->Getpsi() -
fdmex->GetPosition()->GetGroundTrack();
if( diff < -M_PI ) {
return (diff + 2*M_PI);
} else if( diff > M_PI ) {
return (diff - 2*M_PI);
} else {
return diff;
}
}
/*****************************************************************************/
void FGTrimAxis::setControl(void) {
switch(control) {
case tThrottle: setThrottlesPct(); break;
case tBeta: fgic->SetBetaRadIC(control_value); break;
case tAlpha: fgic->SetAlphaRadIC(control_value); break;
case tPitchTrim: fdmex->GetFCS()->SetPitchTrimCmd(control_value); break;
case tElevator: fdmex->GetFCS()->SetDeCmd(control_value); break;
case tRollTrim:
case tAileron: fdmex->GetFCS()->SetDaCmd(control_value); break;
case tYawTrim:
case tRudder: fdmex->GetFCS()->SetDrCmd(control_value); break;
case tAltAGL: fgic->SetAltitudeAGLFtIC(control_value); break;
case tTheta: fgic->SetPitchAngleRadIC(control_value); break;
case tPhi: fgic->SetRollAngleRadIC(control_value); break;
case tGamma: fgic->SetFlightPathAngleRadIC(control_value); break;
case tHeading: fgic->SetTrueHeadingRadIC(control_value); break;
}
}
/*****************************************************************************/
// the aircraft center of rotation is no longer the cg once the gear
// contact the ground so the altitude needs to be changed when pitch
// and roll angle are adjusted. Instead of attempting to calculate the
// new center of rotation, pick a gear unit as a reference and use its
// location vector to calculate the new height change. i.e. new altitude =
// earth z component of that vector (which is in body axes )
void FGTrimAxis::SetThetaOnGround(double ff) {
int center,i,ref;
// favor an off-center unit so that the same one can be used for both
// pitch and roll. An on-center unit is used (for pitch)if that's all
// that's in contact with the ground.
i=0; ref=-1; center=-1;
while( (ref < 0) && (i < fdmex->GetGroundReactions()->GetNumGearUnits()) ) {
if(fdmex->GetGroundReactions()->GetGearUnit(i)->GetWOW()) {
if(fabs(fdmex->GetGroundReactions()->GetGearUnit(i)->GetBodyLocation(2)) > 0.01)
ref=i;
else
center=i;
}
i++;
}
if((ref < 0) && (center >= 0)) {
ref=center;
}
cout << "SetThetaOnGround ref gear: " << ref << endl;
if(ref >= 0) {
double sp=fdmex->GetRotation()->GetSinphi();
double cp=fdmex->GetRotation()->GetCosphi();
double lx=fdmex->GetGroundReactions()->GetGearUnit(ref)->GetBodyLocation(1);
double ly=fdmex->GetGroundReactions()->GetGearUnit(ref)->GetBodyLocation(2);
double lz=fdmex->GetGroundReactions()->GetGearUnit(ref)->GetBodyLocation(3);
double hagl = -1*lx*sin(ff) +
ly*sp*cos(ff) +
lz*cp*cos(ff);
fgic->SetAltitudeAGLFtIC(hagl);
cout << "SetThetaOnGround new alt: " << hagl << endl;
}
fgic->SetPitchAngleRadIC(ff);
cout << "SetThetaOnGround new theta: " << ff << endl;
}
/*****************************************************************************/
bool FGTrimAxis::initTheta(void) {
int i,N,iAft, iForward;
double zAft,zForward,zDiff,theta;
bool level;
double saveAlt;
saveAlt=fgic->GetAltitudeAGLFtIC();
fgic->SetAltitudeAGLFtIC(100);
N=fdmex->GetGroundReactions()->GetNumGearUnits();
//find the first wheel unit forward of the cg
//the list is short so a simple linear search is fine
for( i=0; i<N; i++ ) {
if(fdmex->GetGroundReactions()->GetGearUnit(i)->GetBodyLocation(1) > 0 ) {
iForward=i;
break;
}
}
//now find the first wheel unit aft of the cg
for( i=0; i<N; i++ ) {
if(fdmex->GetGroundReactions()->GetGearUnit(i)->GetBodyLocation(1) < 0 ) {
iAft=i;
break;
}
}
// now adjust theta till the wheels are the same distance from the ground
zAft=fdmex->GetGroundReactions()->GetGearUnit(1)->GetLocalGear(3);
zForward=fdmex->GetGroundReactions()->GetGearUnit(0)->GetLocalGear(3);
zDiff = zForward - zAft;
level=false;
theta=fgic->GetPitchAngleDegIC();
while(!level && (i < 100)) {
theta+=2.0*zDiff;
fgic->SetPitchAngleDegIC(theta);
fdmex->RunIC(fgic);
zAft=fdmex->GetGroundReactions()->GetGearUnit(1)->GetLocalGear(3);
zForward=fdmex->GetGroundReactions()->GetGearUnit(0)->GetLocalGear(3);
zDiff = zForward - zAft;
//cout << endl << theta << " " << zDiff << endl;
//cout << "0: " << fdmex->GetGroundReactions()->GetGearUnit(0)->GetLocalGear() << endl;
//cout << "1: " << fdmex->GetGroundReactions()->GetGearUnit(1)->GetLocalGear() << endl;
if(fabs(zDiff ) < 0.1)
level=true;
i++;
}
//cout << i << endl;
cout << " Initial Theta: " << fdmex->GetRotation()->Gettht()*radtodeg << endl;
control_min=(theta+5)*degtorad;
control_max=(theta-5)*degtorad;
fgic->SetAltitudeAGLFtIC(saveAlt);
if(i < 100)
return true;
else
return false;
}
/*****************************************************************************/
void FGTrimAxis::SetPhiOnGround(double ff) {
int i,ref;
i=0; ref=-1;
//must have an off-center unit here
while( (ref < 0) && (i < fdmex->GetGroundReactions()->GetNumGearUnits()) ) {
if( (fdmex->GetGroundReactions()->GetGearUnit(i)->GetWOW()) &&
(fabs(fdmex->GetGroundReactions()->GetGearUnit(i)->GetBodyLocation(2)) > 0.01))
ref=i;
i++;
}
if(ref >= 0) {
double st=fdmex->GetRotation()->GetSintht();
double ct=fdmex->GetRotation()->GetCostht();
double lx=fdmex->GetGroundReactions()->GetGearUnit(ref)->GetBodyLocation(1);
double ly=fdmex->GetGroundReactions()->GetGearUnit(ref)->GetBodyLocation(2);
double lz=fdmex->GetGroundReactions()->GetGearUnit(ref)->GetBodyLocation(3);
double hagl = -1*lx*st +
ly*sin(ff)*ct +
lz*cos(ff)*ct;
fgic->SetAltitudeAGLFtIC(hagl);
}
fgic->SetRollAngleRadIC(ff);
}
/*****************************************************************************/
void FGTrimAxis::Run(void) {
double last_state_value;
int i;
setControl();
//cout << "FGTrimAxis::Run: " << control_value << endl;
i=0;
bool stable=false;
while(!stable) {
i++;
last_state_value=state_value;
fdmex->RunIC(fgic);
getState();
if(i > 1) {
if((fabs(last_state_value - state_value) < tolerance) || (i >= 100) )
stable=true;
}
}
its_to_stable_value=i;
total_stability_iterations+=its_to_stable_value;
total_iterations++;
}
/*****************************************************************************/
void FGTrimAxis::setThrottlesPct(void) {
double tMin,tMax;
for(unsigned i=0;i<fdmex->GetPropulsion()->GetNumEngines();i++) {
tMin=fdmex->GetPropulsion()->GetEngine(i)->GetThrottleMin();
tMax=fdmex->GetPropulsion()->GetEngine(i)->GetThrottleMax();
//cout << "setThrottlespct: " << i << ", " << control_min << ", " << control_max << ", " << control_value;
fdmex->GetFCS()->SetThrottleCmd(i,tMin+control_value*(tMax-tMin));
//cout << "setThrottlespct: " << fdmex->GetFCS()->GetThrottleCmd(i) << endl;
fdmex->RunIC(fgic); //apply throttle change
fdmex->GetPropulsion()->GetSteadyState();
}
}
/*****************************************************************************/
void FGTrimAxis::AxisReport(void) {
char out[80];
sprintf(out," %20s: %6.2f %5s: %9.2e Tolerance: %3.0e\n",
GetControlName().c_str(), GetControl()*control_convert,
GetStateName().c_str(), GetState(), GetTolerance());
cout << out;
}
/*****************************************************************************/
double FGTrimAxis::GetAvgStability( void ) {
if(total_iterations > 0) {
return double(total_stability_iterations)/double(total_iterations);
}
return 0;
}
/*****************************************************************************/
void FGTrimAxis::Debug(void)
{
}
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