Thanks to Jon for finding the problem.
Date started: 01/21/08
Purpose: Encapsulates the buoyant forces
- ------------- Copyright (C) 2008 - 2010 Anders Gidenstam -------------
+ ------------- Copyright (C) 2008 - 2011 Anders Gidenstam -------------
------------- Copyright (C) 2008 Jon S. Berndt (jon@jsbsim.org) -------------
This program is free software; you can redistribute it and/or modify it under
namespace JSBSim {
-static const char *IdSrc = "$Id: FGBuoyantForces.cpp,v 1.17 2011/05/20 03:18:36 jberndt Exp $";
+static const char *IdSrc = "$Id: FGBuoyantForces.cpp,v 1.19 2011/07/01 21:22:25 andgi Exp $";
static const char *IdHdr = ID_BUOYANTFORCES;
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
gasCellJ = FGMatrix33();
for (unsigned int i=0; i < size; i++) {
- FGColumnVector3 v = FDMExec->GetMassBalance()->StructuralToBody( Cells[i]->GetXYZ() );
- // Body basis is in FT.
- const double mass = Cells[i]->GetMass();
-
- // FIXME: Verify that this is the correct way to change between the
- // coordinate frames.
- gasCellJ += Cells[i]->GetInertia() +
- FGMatrix33( 0, - mass*v(1)*v(2), - mass*v(1)*v(3),
- - mass*v(2)*v(1), 0, - mass*v(2)*v(3),
- - mass*v(3)*v(1), - mass*v(3)*v(2), 0 );
+ gasCellJ += Cells[i]->GetInertia();
}
return gasCellJ;
Author: Anders Gidenstam, Jon S. Berndt
Date started: 01/21/08
- ------------- Copyright (C) 2008 - 2010 Anders Gidenstam -------------
+ ------------- Copyright (C) 2008 - 2011 Anders Gidenstam -------------
------------- Copyright (C) 2008 Jon S. Berndt (jon@jsbsim.org) -------------
This program is free software; you can redistribute it and/or modify it under
DEFINITIONS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-#define ID_BUOYANTFORCES "$Id: FGBuoyantForces.h,v 1.12 2011/05/20 03:18:36 jberndt Exp $"
+#define ID_BUOYANTFORCES "$Id: FGBuoyantForces.h,v 1.13 2011/07/01 21:22:25 andgi Exp $"
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FORWARD DECLARATIONS
See FGGasCell for the full configuration file format for gas cells.
@author Anders Gidenstam, Jon S. Berndt
- @version $Id: FGBuoyantForces.h,v 1.12 2011/05/20 03:18:36 jberndt Exp $
+ @version $Id: FGBuoyantForces.h,v 1.13 2011/07/01 21:22:25 andgi Exp $
*/
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
bool Load(Element* element);
/** Gets the total Buoyant force vector.
- @return a force vector. */
+ @return a force vector in lbs. */
const FGColumnVector3& GetForces(void) const {return vTotalForces;}
/** Gets a component of the total Buoyant force vector.
- @return a component of the force vector. */
+ @return a component of the force vector in lbs. */
double GetForces(int idx) const {return vTotalForces(idx);}
/** Gets the total Buoyancy moment vector.
- @return a moment vector. */
+ @return a moment vector in the body frame in lbs ft. */
const FGColumnVector3& GetMoments(void) const {return vTotalMoments;}
/** Gets a component of the total Buoyancy moment vector.
- @return a component of the moment vector. */
+ @return a component of the moment vector in the body frame in lbs ft. */
double GetMoments(int idx) const {return vTotalMoments(idx);}
/** Gets the total gas mass. The gas mass is part of the aircraft's
double GetGasMass(void);
/** Gets the total moment from the gas mass.
- @return a moment vector. */
+ @return a moment vector in the structural frame in lbs in. */
const FGColumnVector3& GetGasMassMoment(void);
- /** Gets the total moments of inertia for the gas mass.
- @return . */
+ /** Gets the total moments of inertia for the gas mass in the body frame.
+ @return moments of inertia matrix in the body frame
+ in slug ft<sup>2</sup>. */
const FGMatrix33& GetGasMassInertia(void);
/** Gets the strings for the current set of gas cells.
private:
vector <FGGasCell*> Cells;
// Buoyant forces and moments. Excluding the gas weight.
- FGColumnVector3 vTotalForces;
- FGColumnVector3 vTotalMoments;
+ FGColumnVector3 vTotalForces; // [lbs]
+ FGColumnVector3 vTotalMoments; // [lbs ft]
// Gas mass related masses, inertias and moments.
- FGMatrix33 gasCellJ;
+ FGMatrix33 gasCellJ; // [slug ft^2]
FGColumnVector3 vGasCellXYZ;
- FGColumnVector3 vXYZgasCell_arm;
+ FGColumnVector3 vXYZgasCell_arm; // [lbs in]
bool NoneDefined;
Author: Anders Gidenstam
Date started: 01/21/2006
- ----- Copyright (C) 2006 - 2008 Anders Gidenstam (anders(at)gidenstam.org) --
+ ----- Copyright (C) 2006 - 2011 Anders Gidenstam (anders(at)gidenstam.org) --
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
namespace JSBSim {
-static const char *IdSrc = "$Id: FGGasCell.cpp,v 1.13 2010/12/29 22:39:25 andgi Exp $";
+static const char *IdSrc = "$Id: FGGasCell.cpp,v 1.14 2011/07/01 21:22:25 andgi Exp $";
static const char *IdHdr = ID_GASCELL;
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
gasCellJ(2,2) = Iyy;
gasCellJ(3,3) = Izz;
Mass = mass;
+ // Transform the moments of inertia to the body frame.
+ gasCellJ += MassBalance->GetPointmassInertia(Mass, GetXYZ());
+
gasCellM.InitMatrix();
gasCellM(eX) +=
GetXYZ(eX) * Mass*slugtolb;
if (no_ballonets > 0) {
// Add the mass, moment and inertia of any ballonets.
- const FGColumnVector3 p = MassBalance->StructuralToBody( GetXYZ() );
-
for (i = 0; i < no_ballonets; i++) {
Mass += Ballonet[i]->GetMass();
- // Add ballonet moments.
+ // Add ballonet moments due to mass (in the structural frame).
gasCellM(eX) +=
Ballonet[i]->GetXYZ(eX) * Ballonet[i]->GetMass()*slugtolb;
gasCellM(eY) +=
gasCellM(eZ) +=
Ballonet[i]->GetXYZ(eZ) * Ballonet[i]->GetMass()*slugtolb;
- // Moments of inertia must be converted to the gas cell frame here.
- FGColumnVector3 v =
- MassBalance->StructuralToBody( Ballonet[i]->GetXYZ() ) - p;
- // Body basis is in FT.
- const double mass = Ballonet[i]->GetMass();
- gasCellJ += Ballonet[i]->GetInertia() +
- FGMatrix33( 0, - mass*v(1)*v(2), - mass*v(1)*v(3),
- - mass*v(2)*v(1), 0, - mass*v(2)*v(3),
- - mass*v(3)*v(1), - mass*v(3)*v(2), 0 );
+ gasCellJ += Ballonet[i]->GetInertia();
}
}
}
Atmosphere = exec->GetAtmosphere();
PropertyManager = exec->GetPropertyManager();
Inertial = exec->GetInertial();
+ MassBalance = exec->GetMassBalance();
ballonetJ = FGMatrix33();
ballonetJ(1,1) = Ixx;
ballonetJ(2,2) = Iyy;
ballonetJ(3,3) = Izz;
+ // Transform the moments of inertia to the body frame.
+ ballonetJ += MassBalance->GetPointmassInertia(GetMass(), GetXYZ());
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Author: Anders Gidenstam
Date started: 01/21/2006
- ----- Copyright (C) 2006 - 2008 Anders Gidenstam (anders(at)gidenstam.org) --
+ ----- Copyright (C) 2006 - 2011 Anders Gidenstam (anders(at)gidenstam.org) --
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
DEFINITIONS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-#define ID_GASCELL "$Id: FGGasCell.h,v 1.10 2009/10/24 22:59:30 jberndt Exp $"
+#define ID_GASCELL "$Id: FGGasCell.h,v 1.11 2011/07/01 21:22:25 andgi Exp $"
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FORWARD DECLARATIONS
/** Get the center of gravity location of the gas cell
(including any ballonets)
- @return CoG location in the structural frame. */
+ @return CoG location in the structural frame in inches. */
const FGColumnVector3& GetXYZ(void) const {return vXYZ;}
/** Get the center of gravity location of the gas cell
(including any ballonets)
- @return CoG location in the structural frame. */
+ @return CoG location in the structural frame in inches. */
double GetXYZ(int idx) const {return vXYZ(idx);}
/** Get the current mass of the gas cell (including any ballonets)
double GetMass(void) const {return Mass;}
/** Get the moments of inertia of the gas cell (including any ballonets)
- @return moments of inertia matrix relative the gas cell location
+ @return moments of inertia matrix in the body frame
in slug ft<sup>2</sup>. */
const FGMatrix33& GetInertia(void) const {return gasCellJ;}
Note that the buoyancy of the gas cell is handled separately by the
FGForce part and not included here.
- @return moment vector in lbs ft. */
+ @return moment vector in the structural frame in lbs in. */
const FGColumnVector3& GetMassMoment(void) const {return gasCellM;}
/** Get the current gas temperature inside the gas cell
std::string type;
int CellNum;
// Structural constants
- double MaxVolume; // [ft�]
- double MaxOverpressure; // [lbs/ft�]
+ double MaxVolume; // [ft^2]
+ double MaxOverpressure; // [lbs/ft^2]
FGColumnVector3 vXYZ; // [in]
double Xradius, Yradius, Zradius; // [ft]
double Xwidth, Ywidth, Zwidth; // [ft]
typedef vector <FGBallonet*> BallonetArray;
BallonetArray Ballonet;
// Variables
- double Pressure; // [lbs/ft�]
+ double Pressure; // [lbs/ft^2]
double Contents; // [mol]
- double Volume; // [ft�]
- double dVolumeIdeal; // [ft�]
+ double Volume; // [ft^2]
+ double dVolumeIdeal; // [ft^2]
double Temperature; // [Rankine]
double Buoyancy; // [lbs] Note: Gross lift.
// Does not include the weight of the gas itself.
double ValveOpen; // 0 <= ValveOpen <= 1 (or higher).
double Mass; // [slug]
- FGMatrix33 gasCellJ; // [slug foot�]
- FGColumnVector3 gasCellM; // [lbs ft]
+ FGMatrix33 gasCellJ; // [slug foot^2]
+ FGColumnVector3 gasCellM; // [lbs in]
FGAuxiliary* Auxiliary;
FGAtmosphere* Atmosphere;
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
/** Models a ballonet inside a gas cell.
- Models a ballonet inside a gas cell.
Not intended to be used outside FGGasCell.
See FGGasCell for the configuration file format.
@author Anders Gidenstam
/** Get the center of gravity location of the ballonet
- @return CoG location in the structural frame. */
+ @return CoG location in the structural frame in inches. */
const FGColumnVector3& GetXYZ(void) const {return vXYZ;}
/** Get the center of gravity location of the ballonet
- @return CoG location in the structural frame. */
+ @return CoG location in the structural frame in inches. */
double GetXYZ(int idx) const {return vXYZ(idx);}
/** Get the current mass of the ballonets
double GetMass(void) const {return Contents * M_air;}
/** Get the moments of inertia of the ballonet
- @return moments of inertia matrix in slug ft<sup>2</sup>. */
+ @return moments of inertia matrix in the body frame in
+ slug ft<sup>2</sup>. */
const FGMatrix33& GetInertia(void) const {return ballonetJ;}
/** Get the current volume of the ballonet
private:
int CellNum;
// Structural constants
- double MaxVolume; // [ft�]
- double MaxOverpressure; // [lbs/ft�]
+ double MaxVolume; // [ft^2]
+ double MaxOverpressure; // [lbs/ft^2]
FGColumnVector3 vXYZ; // [in]
double Xradius, Yradius, Zradius; // [ft]
double Xwidth, Ywidth, Zwidth; // [ft]
FGFunction* BlowerInput; // [ft^3 / sec]
FGGasCell* Parent;
// Variables
- double Pressure; // [lbs/ft�]
+ double Pressure; // [lbs/ft^2]
double Contents; // [mol]
- double Volume; // [ft�]
- double dVolumeIdeal; // [ft�]
+ double Volume; // [ft^2]
+ double dVolumeIdeal; // [ft^2]
double dU; // [lbs ft / sec]
double Temperature; // [Rankine]
double ValveOpen; // 0 <= ValveOpen <= 1 (or higher).
- FGMatrix33 ballonetJ; // [slug foot�]
+ FGMatrix33 ballonetJ; // [slug foot^2]
FGAuxiliary* Auxiliary;
FGAtmosphere* Atmosphere;
FGPropertyManager* PropertyManager;
FGInertial* Inertial;
+ FGMassBalance* MassBalance;
void Debug(int from);
/* Constants. */
projects / flightgear.git / commitdiff