JSBSim Flight Dynamics Model 1.0 (23 February 2013)
An Open Source Flight Dynamics and Control Software Library in C++
Classes | Public Types | Public Member Functions | Static Public Member Functions | Static Public Attributes | Protected Member Functions | Static Protected Member Functions | Static Protected Attributes

FGJSBBase Class Reference

JSBSim Base class. More...

#include <FGJSBBase.h>

Inheritance diagram for FGJSBBase:
Collaboration diagram for FGJSBBase:

List of all members.

Classes

class  Filter
 First order, (low pass / lag) filter. More...
class  Message
 JSBSim Message structure. More...

Public Types

enum  { eL = 1, eM, eN }
 

Moments L, M, N.


enum  { eP = 1, eQ, eR }
 

Rates P, Q, R.


enum  { eU = 1, eV, eW }
 

Velocities U, V, W.


enum  { eX = 1, eY, eZ }
 

Positions X, Y, Z.


enum  { ePhi = 1, eTht, ePsi }
 

Euler angles Phi, Theta, Psi.


enum  { eDrag = 1, eSide, eLift }
 

Stability axis forces, Drag, Side force, Lift.


enum  { eRoll = 1, ePitch, eYaw }
 

Local frame orientation Roll, Pitch, Yaw.


enum  { eNorth = 1, eEast, eDown }
 

Local frame position North, East, Down.


enum  { eLat = 1, eLong, eRad }
 

Locations Radius, Latitude, Longitude.


enum  {
  inNone = 0, inDegrees, inRadians, inMeters,
  inFeet
}
 

Conversion specifiers.


Public Member Functions

 FGJSBBase ()
 Constructor for FGJSBBase.
virtual ~FGJSBBase ()
 Destructor for FGJSBBase.
void disableHighLighting (void)
 Disables highlighting in the console output.
std::string GetVersion (void)
 Returns the version number of JSBSim.
JSBSim Messaging functions
void PutMessage (const Message &msg)
 Places a Message structure on the Message queue.
void PutMessage (const std::string &text)
 Creates a message with the given text and places it on the queue.
void PutMessage (const std::string &text, bool bVal)
 Creates a message with the given text and boolean value and places it on the queue.
void PutMessage (const std::string &text, int iVal)
 Creates a message with the given text and integer value and places it on the queue.
void PutMessage (const std::string &text, double dVal)
 Creates a message with the given text and double value and places it on the queue.
int SomeMessages (void)
 Reads the message on the queue (but does not delete it).
void ProcessMessage (void)
 Reads the message on the queue and removes it from the queue.
Message * ProcessNextMessage (void)
 Reads the next message on the queue and removes it from the queue.

Static Public Member Functions

static double CelsiusToFahrenheit (double celsius)
 Converts from degrees Celsius to degrees Fahrenheit.
static double CelsiusToKelvin (double celsius)
 Converts from degrees Celsius to degrees Kelvin.
static double CelsiusToRankine (double celsius)
 Converts from degrees Celsius to degrees Rankine.
static double Constrain (double min, double value, double max)
 Constrain a value between a minimum and a maximum value.
static bool EqualToRoundoff (double a, float b)
 Finite precision comparison.
static bool EqualToRoundoff (double a, double b)
 Finite precision comparison.
static bool EqualToRoundoff (float a, float b)
 Finite precision comparison.
static bool EqualToRoundoff (float a, double b)
 Finite precision comparison.
static double FahrenheitToCelsius (double fahrenheit)
 Converts from degrees Fahrenheit to degrees Celsius.
static double KelvinToCelsius (double kelvin)
 Converts from degrees Kelvin to degrees Celsius.
static double KelvinToFahrenheit (double kelvin)
 Converts from degrees Kelvin to degrees Fahrenheit.
static double KelvinToRankine (double kelvin)
 Converts from degrees Kelvin to degrees Rankine.
static double MachFromVcalibrated (double vcas, double p, double psl, double rhosl)
 Calculate the Mach number from the calibrated airspeed.
static double RankineToCelsius (double rankine)
 Converts from degrees Rankine to degrees Celsius.
static double RankineToKelvin (double rankine)
 Converts from degrees Rankine to degrees Kelvin.
static double sign (double num)
static double VcalibratedFromMach (double mach, double p, double psl, double rhosl)
 Calculate the calibrated airspeed from the Mach number.

Static Public Attributes

static short debug_lvl = 1
JSBSim console output highlighting terms.
static char highint [5] = {27, '[', '1', 'm', '\0' }
 highlights text
static char halfint [5] = {27, '[', '2', 'm', '\0' }
 low intensity text
static char normint [6] = {27, '[', '2', '2', 'm', '\0' }
 normal intensity text
static char reset [5] = {27, '[', '0', 'm', '\0' }
 resets text properties
static char underon [5] = {27, '[', '4', 'm', '\0' }
 underlines text
static char underoff [6] = {27, '[', '2', '4', 'm', '\0' }
 underline off
static char fgblue [6] = {27, '[', '3', '4', 'm', '\0' }
 blue text
static char fgcyan [6] = {27, '[', '3', '6', 'm', '\0' }
 cyan text
static char fgred [6] = {27, '[', '3', '1', 'm', '\0' }
 red text
static char fggreen [6] = {27, '[', '3', '2', 'm', '\0' }
 green text
static char fgdef [6] = {27, '[', '3', '9', 'm', '\0' }
 default text

Protected Member Functions

void Debug (int)

Static Protected Member Functions

static std::string CreateIndexedPropertyName (const std::string &Property, int index)
static double GaussianRandomNumber (void)

Static Protected Attributes

static const double degtorad = 0.017453292519943295769236907684886
static const double fpstokts = 0.592484
static const double fttom = 0.3048
static const double hptoftlbssec = 550.0
static const double in3tom3 = 1.638706E-5
static const double inchtoft = 0.08333333
static const double inhgtopa = 3386.38
static const std::string JSBSim_version = " " __TIME__
static const double kgtolb = 2.20462
static const double kgtoslug = 0.06852168
static const double ktstofps = 1.68781
static const double lbtoslug = 1.0/slugtolb
static Message localMsg
static const double m3toft3 = 1.0/(fttom*fttom*fttom)
static double Mair = 28.9645
static unsigned int messageId = 0
static std::queue< Message > Messages
static const std::string needed_cfg_version = "2.0"
static const double psftoinhg = 0.014138
static const double psftopa = 47.88
static const double radtodeg = 57.295779513082320876798154814105
static double Reng = 1716.56
static double Rstar = 1545.348
static const double SHRatio = 1.40
static const double slugtolb = 32.174049

Detailed Description

This class provides universal constants, utility functions, messaging functions, and enumerated constants to JSBSim.

Author:
Jon S. Berndt
Version:
Id:
FGJSBBase.h,v 1.36 2012/03/25 11:05:36 bcoconni Exp

Definition at line 82 of file FGJSBBase.h.

Member Function Documentation

static double CelsiusToFahrenheit ( double  celsius) [inline, static]
Parameters:
celsiusThe temperature in degrees Celsius.
Returns:
The temperature in Fahrenheit.

Definition at line 241 of file FGJSBBase.h.

Referenced by FGTank::GetTemperature().

                                                     {
    return celsius * 1.8 + 32.0;
  }

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static double CelsiusToKelvin ( double  celsius) [inline, static]
Parameters:
celsiusThe temperature in degrees Celsius.
Returns:
The temperature in Kelvin.

Definition at line 248 of file FGJSBBase.h.

                                                 {
    return celsius + 273.15;
  }
static double CelsiusToRankine ( double  celsius) [inline, static]
Parameters:
celsiusThe temperature in degrees Celsius.
Returns:
The temperature in Rankine.

Definition at line 206 of file FGJSBBase.h.

                                                  {
    return celsius * 1.8 + 491.67;
  }
static bool EqualToRoundoff ( double  a,
double  b 
) [inline, static]
Parameters:
afirst value to compare
bsecond value to compare
Returns:
if the two values can be considered equal up to roundoff

Definition at line 286 of file FGJSBBase.h.

Referenced by FGJSBBase::EqualToRoundoff(), and FGKinemat::Run().

                                                  {
    double eps = 2.0*DBL_EPSILON;
    return std::fabs(a - b) <= eps * max(std::fabs(a), std::fabs(b));
  }

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static bool EqualToRoundoff ( float  a,
float  b 
) [inline, static]
Parameters:
afirst value to compare
bsecond value to compare
Returns:
if the two values can be considered equal up to roundoff

Definition at line 295 of file FGJSBBase.h.

                                                {
    float eps = 2.0*FLT_EPSILON;
    return std::fabs(a - b) <= eps * max(std::fabs(a), std::fabs(b));
  }
static bool EqualToRoundoff ( double  a,
float  b 
) [inline, static]
Parameters:
afirst value to compare
bsecond value to compare
Returns:
if the two values can be considered equal up to roundoff

Definition at line 312 of file FGJSBBase.h.

References FGJSBBase::EqualToRoundoff().

                                                 {
    return EqualToRoundoff((float)a, b);
  }

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static bool EqualToRoundoff ( float  a,
double  b 
) [inline, static]
Parameters:
afirst value to compare
bsecond value to compare
Returns:
if the two values can be considered equal up to roundoff

Definition at line 304 of file FGJSBBase.h.

References FGJSBBase::EqualToRoundoff().

                                                 {
    return EqualToRoundoff(a, (float)b);
  }

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static double FahrenheitToCelsius ( double  fahrenheit) [inline, static]
Parameters:
fahrenheitThe temperature in degrees Fahrenheit.
Returns:
The temperature in Celsius.

Definition at line 234 of file FGJSBBase.h.

Referenced by FGTank::FGTank().

                                                        {
    return (fahrenheit - 32.0)/1.8;
  }

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std::string GetVersion ( void  ) [inline]
Returns:
The version number of JSBSim.

Definition at line 189 of file FGJSBBase.h.

{return JSBSim_version;}
static double KelvinToCelsius ( double  kelvin) [inline, static]
Parameters:
celsiusThe temperature in degrees Kelvin.
Returns:
The temperature in Celsius.

Definition at line 255 of file FGJSBBase.h.

                                                {
    return kelvin - 273.15;
  }
static double KelvinToFahrenheit ( double  kelvin) [inline, static]
Parameters:
kelvinThe temperature in degrees Kelvin.
Returns:
The temperature in Fahrenheit.

Definition at line 199 of file FGJSBBase.h.

                                                   {
    return 1.8*kelvin - 459.4;
  }
static double KelvinToRankine ( double  kelvin) [inline, static]
Parameters:
kelvinThe temperature in degrees Kelvin.
Returns:
The temperature in Rankine.

Definition at line 220 of file FGJSBBase.h.

                                                {
    return kelvin * 1.8;
  }
double MachFromVcalibrated ( double  vcas,
double  p,
double  psl,
double  rhosl 
) [static]

For subsonic speeds, the reversed formula has a closed form. For supersonic speeds, the Rayleigh formula is reversed by the Newton-Raphson algorithm.

Parameters:
vcasThe calibrated airspeed (CAS) in ft/s
pPressure in psf
pslPressure at sea level in psf
rhoslDensity at sea level in slugs/ft^3
Returns:
The Mach number

Definition at line 318 of file FGJSBBase.cpp.

Referenced by FGInitialCondition::SetAltitudeASLFtIC(), and FGInitialCondition::SetVcalibratedKtsIC().

{
  double pt = p + psl*(pow(1+vcas*vcas*rhosl/(7.0*psl),3.5)-1);

  if (pt/p < 1.89293)
    return sqrt(5.0*(pow(pt/p, 0.2857143) -1)); // Mach < 1
  else {
    // Mach >= 1
    double mach = sqrt(0.77666*pt/p); // Initial guess is based on a quadratic approximation of the Rayleigh formula
    double delta = 1.;
    double target = pt/(166.92158*p);
    int iter = 0;

    // Find the root with Newton-Raphson. Since the differential is never zero,
    // the function is monotonic and has only one root with a multiplicity of one.
    // Convergence is certain.
    while (delta > 1E-5 && iter < 10) {
      double m2 = mach*mach; // Mach^2
      double m6 = m2*m2*m2;  // Mach^6
      delta = mach*m6/pow(7.0*m2-1.0,2.5) - target;
      double diff = 7.0*m6*(2.0*m2-1)/pow(7.0*m2-1.0,3.5); // Never zero when Mach >= 1
      mach -= delta/diff;
      iter++;
    }

    return mach;
  }
}

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void ProcessMessage ( void  )

This function also prints out the message.

Definition at line 188 of file FGJSBBase.cpp.

{
  if (Messages.empty()) return;
  localMsg = Messages.front();

  while (Messages.size() > 0) {
      switch (localMsg.type) {
      case JSBSim::FGJSBBase::Message::eText:
        cout << localMsg.messageId << ": " << localMsg.text << endl;
        break;
      case JSBSim::FGJSBBase::Message::eBool:
        cout << localMsg.messageId << ": " << localMsg.text << " " << localMsg.bVal << endl;
        break;
      case JSBSim::FGJSBBase::Message::eInteger:
        cout << localMsg.messageId << ": " << localMsg.text << " " << localMsg.iVal << endl;
        break;
      case JSBSim::FGJSBBase::Message::eDouble:
        cout << localMsg.messageId << ": " << localMsg.text << " " << localMsg.dVal << endl;
        break;
      default:
        cerr << "Unrecognized message type." << endl;
        break;
      }
      Messages.pop();
      if (Messages.size() > 0) localMsg = Messages.front();
      else break;
  }

}
FGJSBBase::Message * ProcessNextMessage ( void  )

This function also prints out the message.

Returns:
a pointer to the message, or NULL if there are no messages.

Definition at line 220 of file FGJSBBase.cpp.

{
  if (Messages.empty()) return NULL;
  localMsg = Messages.front();

  Messages.pop();
  return &localMsg;
}
void PutMessage ( const std::string &  text,
bool  bVal 
)
Parameters:
textmessage text
bValboolean value associated with the message
Returns:
pointer to a Message structure

Definition at line 142 of file FGJSBBase.cpp.

{
  Message msg;
  msg.text = text;
  msg.messageId = messageId++;
  msg.subsystem = "FDM";
  msg.type = Message::eBool;
  msg.bVal = bVal;
  Messages.push(msg);
}
void PutMessage ( const std::string &  text,
int  iVal 
)
Parameters:
textmessage text
iValinteger value associated with the message
Returns:
pointer to a Message structure

Definition at line 155 of file FGJSBBase.cpp.

{
  Message msg;
  msg.text = text;
  msg.messageId = messageId++;
  msg.subsystem = "FDM";
  msg.type = Message::eInteger;
  msg.iVal = iVal;
  Messages.push(msg);
}
void PutMessage ( const std::string &  text)
Parameters:
textmessage text
Returns:
pointer to a Message structure

Definition at line 130 of file FGJSBBase.cpp.

{
  Message msg;
  msg.text = text;
  msg.messageId = messageId++;
  msg.subsystem = "FDM";
  msg.type = Message::eText;
  Messages.push(msg);
}
void PutMessage ( const Message &  msg)
Parameters:
msgpointer to a Message structure
Returns:
pointer to a Message structure

Definition at line 123 of file FGJSBBase.cpp.

{
  Messages.push(msg);
}
void PutMessage ( const std::string &  text,
double  dVal 
)
Parameters:
textmessage text
dValdouble value associated with the message
Returns:
pointer to a Message structure

Definition at line 168 of file FGJSBBase.cpp.

{
  Message msg;
  msg.text = text;
  msg.messageId = messageId++;
  msg.subsystem = "FDM";
  msg.type = Message::eDouble;
  msg.dVal = dVal;
  Messages.push(msg);
}
static double RankineToCelsius ( double  rankine) [inline, static]
Parameters:
rankineThe temperature in degrees Rankine.
Returns:
The temperature in Celsius.

Definition at line 213 of file FGJSBBase.h.

Referenced by FGAuxiliary::FGAuxiliary(), and FGAuxiliary::Run().

                                                  {
    return (rankine - 491.67)/1.8;
  }

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static double RankineToKelvin ( double  rankine) [inline, static]
Parameters:
rankineThe temperature in degrees Rankine.
Returns:
The temperature in Kelvin.

Definition at line 227 of file FGJSBBase.h.

Referenced by FGPiston::Calculate(), and FGPiston::ResetToIC().

                                                 {
    return rankine/1.8;
  }

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int SomeMessages ( void  )
Returns:
1 if some messages

Definition at line 181 of file FGJSBBase.cpp.

{
  return !Messages.empty();
}
double VcalibratedFromMach ( double  mach,
double  p,
double  psl,
double  rhosl 
) [static]

It uses the Rayleigh formula for supersonic speeds (See "Introduction to Aerodynamics of a Compressible Fluid - H.W. Liepmann, A.E. Puckett - Wiley & sons (1947)" ยง5.4 pp 75-80)

Parameters:
machThe Mach number
pPressure in psf
pslPressure at sea level in psf
rhoslDensity at sea level in slugs/ft^3
Returns:
The calibrated airspeed (CAS) in ft/s

Definition at line 286 of file FGJSBBase.cpp.

Referenced by FGInitialCondition::GetVcalibratedKtsIC(), and FGInitialCondition::SetAltitudeASLFtIC().

{
  double pt,A;

  if (mach < 0) mach=0;
  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 of
    // the normal shock assumption should not be a bad one -- most supersonic
    // aircraft place the pitot probe out front so that it is the forward
    // most point on the aircraft.  The real shock would, of course, take
    // on something like the shape of a rounded-off cone but, here again,
    // the assumption should be good since the opening of the pitot probe
    // is very small and, therefore, the effects of the shock curvature
    // should be small as well. AFAIK, this approach is fairly well accepted
    // within the aerospace community

    // The denominator below is zero for Mach ~ 0.38, for which
    // we'll never be here, so we're safe

    pt = p*166.92158*pow(mach,7.0)/pow(7*mach*mach-1,2.5);
  }

  A = pow(((pt-p)/psl+1),0.28571);
  return sqrt(7*psl/rhosl*(A-1));
}

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The documentation for this class was generated from the following files: