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Add the BalloonSim and MagicCarpet fdm's back in (i seriously thought this had been done, oops)

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ehofman 2008-07-26 07:19:13 +00:00
parent f6301ea1d7
commit a40e040e24
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/*****************************************************************************
Module: BalloonSimInterface.cxx
Author: Christian Mayer
Date started: 07.10.99
Called by:
-------- Copyright (C) 1999 Christian Mayer (fgfs@christianmayer.de) --------
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Further information about the GNU General Public License can also be found on
the world wide web at http://www.gnu.org.
FUNCTIONAL DESCRIPTION
------------------------------------------------------------------------------
Interface to the hot air balloon simulator
HISTORY
------------------------------------------------------------------------------
01.09.1999 Christian Mayer Created
*****************************************************************************/
/****************************************************************************/
/* INCLUDES */
/****************************************************************************/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <simgear/compiler.h>
#include <string>
#include <simgear/constants.h>
#include <simgear/debug/logstream.hxx>
#include <simgear/math/sg_geodesy.hxx>
#include <simgear/misc/sg_path.hxx>
#include <Aircraft/aircraft.hxx>
#include <Main/globals.hxx>
#include <Main/fg_props.hxx>
#include "Balloon.h"
/****************************************************************************/
/********************************** CODE ************************************/
/****************************************************************************/
FGBalloonSim::FGBalloonSim( double dt ) {
//set the dt of the model
current_balloon.set_dt(dt);
}
FGBalloonSim::~FGBalloonSim() {
}
// Initialize the BalloonSim flight model, dt is the time increment for
// each subsequent iteration through the EOM
void FGBalloonSim::init() {
//do init common to all the FDM's
common_init();
//now do init specific to the Balloon
sgVec3 temp;
SG_LOG( SG_FLIGHT, SG_INFO, "Starting initializing BalloonSim" );
SG_LOG( SG_FLIGHT, SG_INFO, " created a balloon" );
//set position
sgSetVec3( temp,
get_Latitude(),
get_Longitude(),
get_Altitude() * SG_FEET_TO_METER);
current_balloon.setPosition( temp );
//set Euler angles (?)
sgSetVec3( temp,
get_Phi(),
get_Theta(),
get_Psi() );
current_balloon.setHPR( temp );
//set velocities
sgSetVec3( temp,
fgGetDouble("/sim/presets/uBody-fps"),
fgGetDouble("/sim/presets/vBody-fps"),
fgGetDouble("/sim/presets/wBody-fps") );
current_balloon.setVelocity( temp );
SG_LOG( SG_FLIGHT, SG_INFO, "Finished initializing BalloonSim" );
}
// Run an iteration of the EOM (equations of motion)
void FGBalloonSim::update( double dt ) {
double save_alt = 0.0;
if (is_suspended())
return;
int multiloop = _calc_multiloop(dt);
// lets try to avoid really screwing up the BalloonSim model
if ( get_Altitude() < -9000 ) {
save_alt = get_Altitude();
set_Altitude( 0.0 );
}
// set control positions
current_balloon.set_burner_strength ( globals->get_controls()->get_throttle(0) );
//not more implemented yet
// Inform BalloonSim of the local terrain altitude
current_balloon.setGroundLevel ( get_Runway_altitude() * SG_FEET_TO_METER);
// old -- FGInterface_2_JSBsim() not needed except for Init()
// translate FG to JSBsim structure
// FGInterface_2_JSBsim(f);
// printf("FG_Altitude = %.2f\n", FG_Altitude * 0.3048);
// printf("Altitude = %.2f\n", Altitude * 0.3048);
// printf("Radius to Vehicle = %.2f\n", Radius_to_vehicle * 0.3048);
/* FDMExec.GetState()->Setsim_time(State->Getsim_time()
+ State->Getdt() * multiloop); */
for ( int i = 0; i < multiloop; i++ ) {
current_balloon.update();
}
// translate BalloonSim back to FG structure so that the
// autopilot (and the rest of the sim can use the updated
// values
copy_from_BalloonSim();
/*sgVec3 temp, temp2;
current_balloon.getPosition( temp );
current_balloon.getVelocity( temp2 );
SG_LOG( SG_FLIGHT, SG_INFO, "T: " << current_balloon.getTemperature() <<
" alt: " << temp[2] <<
" gr_alt: " << get_Runway_altitude() <<
" burner: " << controls.get_elevator() <<
" v[2]: " << temp2[2]); */
// but lets restore our original bogus altitude when we are done
if ( save_alt < -9000.0 ) {
set_Altitude( save_alt );
}
}
// Convert from the FGInterface struct to the BalloonSim
bool FGBalloonSim::copy_to_BalloonSim() {
return true;
}
// Convert from the BalloonSim to the FGInterface struct
bool FGBalloonSim::copy_from_BalloonSim() {
sgVec3 temp;
// Velocities
current_balloon.getVelocity( temp );
_set_Velocities_Local( temp[0], temp[1], temp[2] );
/* ***FIXME*** */ _set_V_equiv_kts( sgLengthVec3 ( temp ) );
_set_Omega_Body( 0.0, 0.0, 0.0 );
// Positions
current_balloon.getPosition( temp );
//temp[0]: geocentric latitude
//temp[1]: longitude
//temp[2]: altitude (meters)
_updateGeocentricPosition( temp[0], temp[1], temp[2] * SG_METER_TO_FEET );
current_balloon.getHPR( temp );
set_Euler_Angles( temp[0], temp[1], temp[2] );
return true;
}

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/*****************************************************************************
Header: BalloonSimInterface.h
Author: Christian Mayer
Date started: 07.10.99
-------- Copyright (C) 1999 Christian Mayer (fgfs@christianmayer.de) --------
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Further information about the GNU General Public License can also be found on
the world wide web at http://www.gnu.org.
FUNCTIONAL DESCRIPTION
------------------------------------------------------------------------------
interface to the the hot air balloon simulator
HISTORY
------------------------------------------------------------------------------
07.10.1999 Christian Mayer Created
*****************************************************************************/
/****************************************************************************/
/* SENTRY */
/****************************************************************************/
#ifndef BalloonSimInterface_H
#define BalloonSimInterface_H
/****************************************************************************/
/* INCLUDES */
/****************************************************************************/
#include <Aircraft/aircraft.hxx>
#include <FDM/flight.hxx>
#include "BalloonSim.h"
/****************************************************************************/
/* DEFINES */
/****************************************************************************/
/****************************************************************************/
/* DECLARATIONS */
/****************************************************************************/
class FGBalloonSim: public FGInterface {
balloon current_balloon;
public:
FGBalloonSim( double dt );
~FGBalloonSim();
// copy FDM state to BalloonSim structures
bool copy_to_BalloonSim();
// copy FDM state from BalloonSim structures
bool copy_from_BalloonSim();
// reset flight params to a specific position
void init();
// update position based on inputs, positions, velocities, etc.
void update( double dt );
};
/****************************************************************************/
#endif /*BalloonSimInterface_H*/

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/*****************************************************************************
Module: BalloonSim.cpp
Author: Christian Mayer
Date started: 01.09.99
Called by:
-------- Copyright (C) 1999 Christian Mayer (fgfs@christianmayer.de) --------
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Further information about the GNU General Public License can also be found on
the world wide web at http://www.gnu.org.
FUNCTIONAL DESCRIPTION
------------------------------------------------------------------------------
A hot air balloon simulator
HISTORY
------------------------------------------------------------------------------
01.09.1999 Christian Mayer Created
03.10.1999 Christian Mayer cleaned the code by moveing WeatherDatabase
calls inside the update()
*****************************************************************************/
/****************************************************************************/
/* INCLUDES */
/****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
// #include <conio.h>
#include <math.h>
#include <simgear/constants.h>
#include <Aircraft/aircraft.hxx>
#include "BalloonSim.h"
#include <plib/sg.h>
/****************************************************************************/
/********************************** CODE ************************************/
/****************************************************************************/
/****************************************************************************/
/* */
/* Constructor: */
/* Set the balloon model to some values that seem reasonable as I haven't */
/* got much original values */
/* */
/****************************************************************************/
balloon::balloon()
{
dt = 0.1;
ground_level = 3400.0;
sgSetVec3(gravity_vector, 0.0, 0.0, -9.81);
sgSetVec3(velocity, 0.0, 0.0, 0.0);
sgSetVec3(position, 0.0, 0.0, 0.0);
sgSetVec3(hpr, 0.0, 0.0, 0.0);
/************************************************************************/
/* My balloon has a radius of 8.8 metres as that gives a envelope */
/* volume of about 2854 m^3 which is about 77000 ft^3, a very common */
/* size for hot air balloons */
/************************************************************************/
balloon_envelope_area = 4.0 * (8.8 * 8.8) * SGD_PI;
balloon_envelope_volume = (4.0/3.0) * (8.8 * 8.8 * 8.8) * SGD_PI;
wind_facing_area_of_balloon = SGD_PI * (8.8 * 8.8);
wind_facing_area_of_basket = 2.0; //guessed: 2 m^2
cw_envelope=0.45; //a sphere in this case
cw_basket=0.8;
weight_of_total_fuel = 40.0; //big guess
weight_of_envelope = 200.0; //big guess
weight_of_basket = 40.0; //big guess
weight_of_cargo = 750.0; //big guess
fuel_left=1.0;
max_flow_of_fuel_per_second=10.0*1.0/3600.0; //assuming 10% of one hour of total burn time
current_burner_strength = 0.0; //the throttle
lambda = 0.15; //for plasic
l_of_the_envelope = 1.0/1000.0; //the thickness of the envelope (in m): 1mm
T = 273.16 + 130.6; //Temperature in the envelope => still at ground level
}
void balloon::update()
{
/************************************************************************/
/* I'm simplifying the balloon by reducing the simulation to two */
/* points: */
/* the center of the basket (CB) and the center of the envelope (CE) */
/* */
/* ce */
/* I */
/* I */
/* cg (=center of gravity) */
/* I */
/* cb */
/* */
/* On each center are forces acting: gravity and wind resitance. CE */
/* additionally got the lift (=> I need to calculate the weight of the */
/* air inside, too) */
/* */
/* The weight of the air in the envelope is dependant of the tempera- */
/* ture. This temperature is decreasing over the time that is dependant */
/* of the insulation of the envelope material (lambda), the gas used */
/* (air) and the wind speed. For a plane surface it's for air: */
/* */
/* alpha = 4.8 + 3.4*v with v < 5.0 m/s */
/* */
/* The value k that takes all of that into account is defined as: */
/* */
/* 1 / k = 1 / alpha1 + 1 / alpha2 + l / lambda */
/* */
/* with 'l' beeing the 'length' i.e. thickness of the insulator, alpha1 */
/* the air inside and alpha2 the air outside of the envelope. So our k */
/* is: */
/* */
/* k = 1 / [1/4.8 + 1/(4.8+3.4v) + l/lambda] */
/* */
/* The energy lost by this process is defined as: */
/* */
/* dQ = k * A * t * dT */
/* */
/* with Q being the energy, k that value defined above, A the total */
/* area of the envelope, t the time (in hours) and dT the temperature */
/* difference between the inside and the outside. */
/* To get the temperature of the air in the inside I need the formula: */
/* */
/* dQ = cAir * m * dT */
/* */
/* with cAir being the specific heat capacity(?) of air (= 1.00 kcal / */
/* kg * degree), m the mass of the air and dT the temperature change. */
/* As the envelope is open I'm assuming that the same air pressure is */
/* inside and outside of it (practical there should be a slightly */
/* higher air pressure in the inside or the envelope would collapse). */
/* So it's easy to calculate the density of the air inside: */
/* */
/* rho = p / R * T */
/* */
/* with p being the pressure, R the gas constant(?) which is for air */
/* 287.14 N * m / kg * K and T the absolute temperature. */
/* */
/* The value returned by this function is the displacement of the CB */
/************************************************************************/
/************************************************************************/
/* NOTE: This is the simplified version: I'm assuming that the whole */
/* balloon consists only of the envelope.I will improove the simulation */
/* later, but currently was my main concern to get it going... */
/************************************************************************/
// I realy don't think there is a solution for this without WeatherCM
// but this is a hack, and it's working -- EMH
double mAir = 1;
float Q = 0;
// gain of energy by heating:
if (fuel_left > 0.0) //but only with some fuel left ;-)
{
float fuel_burning = current_burner_strength * max_flow_of_fuel_per_second * dt * weight_of_total_fuel; //in kg
//convert to cubemetres (I'm wrongly assuming 'normal' conditions; but that's correct for my special case)
float cube_metres_burned = fuel_burning / 2.2; //2.2 is the density for propane
fuel_left -= fuel_burning / weight_of_total_fuel;
// get energy through burning.
Q += 22250.0 * cube_metres_burned; //22250 for propan, 29500 would be butane and if you dare: 2580 would be hydrogen...
}
// calculate the new temperature in the inside:
T += Q / (1.00 * mAir);
//calculate the masses of the envelope and the basket
float mEnvelope = mAir + weight_of_envelope;
float mBasket = weight_of_total_fuel*fuel_left + weight_of_basket + weight_of_cargo;
float mTotal = mEnvelope + mBasket;
//calulate the forces
sgVec3 fTotal, fFriction, fLift;
sgScaleVec3(fTotal, gravity_vector, mTotal);
//sgAddVec3(fTotal, fLift); //FIXME: uninitialized fLift
//sgAddVec3(fTotal, fFriction); //FIXME: uninitialized fFriction
//claculate acceleration: a = F / m
sgVec3 aTotal, vTotal, dTotal;
sgScaleVec3(aTotal, fTotal, 1.0 / mTotal);
//integrate the displacement: d = 0.5 * a * dt**2 + v * dt + d
sgScaleVec3(vTotal, velocity, dt);
sgScaleVec3(dTotal, aTotal, 0.5*dt*dt); sgAddVec3(dTotal, vTotal);
//integrate the velocity to 'velocity': v = a * dt + v
sgScaleVec3(vTotal, aTotal, dt); sgAddVec3(velocity, vTotal);
/************************************************************************/
/* VERY WRONG STUFF: it's just here to get some results to start with */
/************************************************************************/
// care for the ground
if (position[2] < (ground_level+0.001) )
position[2] = ground_level;
//return results
sgAddVec3(position, dTotal);
//cout << "BallonSim: T: " << (T-273.16) << " alt: " << position[2] << " ground: " << ground_level << " throttle: " << current_burner_strength << "\n";
}
void balloon::set_burner_strength(const float bs)
{
if ((bs>=0.0) && (bs<=1.0))
current_burner_strength = bs;
}
void balloon::getVelocity(sgVec3 v) const
{
sgCopyVec3(v, velocity);
}
void balloon::setVelocity(const sgVec3 v)
{
sgCopyVec3(velocity, v);
}
void balloon::getPosition(sgVec3 v) const
{
sgCopyVec3(v, position);
}
void balloon::setPosition(const sgVec3 v)
{
sgCopyVec3(position, v);
}
void balloon::getHPR(sgVec3 angles) const //the balloon isn't allways exactly vertical
{
sgCopyVec3(angles, hpr);
}
void balloon::setHPR(const sgVec3 angles) //the balloon isn't allways exactly vertical
{
sgCopyVec3(hpr, angles);
}
void balloon::setGroundLevel(const float altitude)
{
ground_level = altitude;
}
float balloon::getTemperature(void) const
{
return T;
}
float balloon::getFuelLeft(void) const
{
return fuel_left;
}
/*
void main(void)
{
bool burner = true;
balloon bal;
bool exit = false;
sgVec3 pos={0.0, 0.0, 0.0};
char c;
float acc_dt = 0.0;
float alt;
bool hysteresis = false; // moving up
for (;!exit;)
{
for (int i=0; i<100; i++)
{
bal.update(0.1); acc_dt += 0.1;
bal.getPosition(pos);
alt = pos[2];
if (alt > 3010)
{
hysteresis = true;
burner = false;
}
if ((alt < 2990) && (hysteresis == true))
{
hysteresis = false;
burner = true;
}
if ((bal.getTemperature()-273.16)>250.0)
burner = false; //emergency
}
// toogle burner
c = getch();
if (c==' ')
burner=!burner;
//if (c=='s')
// show=!show;
//printf("Position: (%f/%f/%f), dP: (%f/%f/%f), burner: ", pos[0], pos[1], pos[2], dp[0], dp[1], dp[2]);
printf("%f \t%f \t%f \t%f\n", acc_dt/60.0, bal.getTemperature()-273.16, pos[2], bal.getFuelLeft());
if (burner==true)
{
//printf("on\n");
bal.set_burner_strength(1.0);
}
else
{
//printf("off\n");
bal.set_burner_strength(0.0);
}
}
}
*/

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/*****************************************************************************
Header: BalloonSim.h
Author: Christian Mayer
Date started: 01.09.99
-------- Copyright (C) 1999 Christian Mayer (fgfs@christianmayer.de) --------
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Further information about the GNU General Public License can also be found on
the world wide web at http://www.gnu.org.
FUNCTIONAL DESCRIPTION
------------------------------------------------------------------------------
Header for the hot air balloon simulator
HISTORY
------------------------------------------------------------------------------
01.09.1999 Christian Mayer Created
03.10.1999 Christian Mayer cleaned the code by moveing WeatherDatabase
calls inside the update()
*****************************************************************************/
/****************************************************************************/
/* SENTRY */
/****************************************************************************/
#ifndef BalloonSim_H
#define BalloonSim_H
/****************************************************************************/
/* INCLUDES */
/****************************************************************************/
#include <plib/sg.h>
/****************************************************************************/
/* DEFINES */
/****************************************************************************/
/****************************************************************************/
/* CLASS DECLARATION */
/****************************************************************************/
class balloon
{
private:
float dt; //in s
sgVec3 gravity_vector; //in m/s*s
sgVec3 hpr; //the balloon isn't allways exactly vertical (e.g. during gusts); normalized
sgVec3 velocity; //current velocity; it gets iterated at each 'update'
sgVec3 position; //current position in lat/lon/alt
float balloon_envelope_area; //area of the envelope
float balloon_envelope_volume; //volume of the envelope
float wind_facing_area_of_balloon;
float wind_facing_area_of_basket;
float cw_envelope; //wind resistance of the envelope
float cw_basket; //wind resistance of the bakset
//all weights in kg
float weight_of_total_fuel;
float weight_of_envelope;
float weight_of_basket; //weight of all the unmovable stuff such as the basket, the burner and the empty tanks
float weight_of_cargo; //passengers and anything left (e.g. sand bags that are thrown away to give additional lift)
float fuel_left; //as a percentage
float max_flow_of_fuel_per_second; //in percent per second
float current_burner_strength;
float lambda; //waermeuebergangskoeffizient (heat transmission coefficent?!?) for the envelope
float l_of_the_envelope; //the thickness of the envelope (in m)
float T; //tempereature inside the balloon
float ground_level;
public:
balloon(); //constructor for initializing the balloon
void update(); //dt = time in seconds since last call
void set_burner_strength(const float bs);
void getVelocity(sgVec3 v) const;
void setVelocity(const sgVec3 v);
void getPosition(sgVec3 v) const;
void setPosition(const sgVec3 v);
void getHPR(sgVec3 angles) const; //the balloon isn't allways exactly vertical
void setHPR(const sgVec3 angles); //the balloon isn't allways exactly vertical
void setGroundLevel(const float altitude);
float getTemperature(void) const;
float getFuelLeft(void) const;
void set_dt(const float new_dt) { dt = new_dt; }
};
/****************************************************************************/
#endif /*BalloonSim_H*/

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// MagicCarpet.cxx -- interface to the "Magic Carpet" flight model
//
// Written by Curtis Olson, started October 1999.
//
// Copyright (C) 1999 Curtis L. Olson - http://www.flightgear.org/~curt
//
// 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// $Id$
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <simgear/math/sg_geodesy.hxx>
#include <simgear/math/point3d.hxx>
#include <simgear/math/polar3d.hxx>
#include <Aircraft/controls.hxx>
#include <Main/globals.hxx>
#include <Main/fg_props.hxx>
#include "MagicCarpet.hxx"
FGMagicCarpet::FGMagicCarpet( double dt ) {
// set_delta_t( dt );
}
FGMagicCarpet::~FGMagicCarpet() {
}
// Initialize the Magic Carpet flight model, dt is the time increment
// for each subsequent iteration through the EOM
void FGMagicCarpet::init() {
common_init();
}
// Run an iteration of the EOM (equations of motion)
void FGMagicCarpet::update( double dt ) {
// cout << "FGLaRCsim::update()" << endl;
if (is_suspended())
return;
// int multiloop = _calc_multiloop(dt);
double time_step = dt;
// speed and distance traveled
double speed = globals->get_controls()->get_throttle( 0 ) * 2000; // meters/sec
if ( globals->get_controls()->get_brake_left() > 0.0
|| globals->get_controls()->get_brake_right() > 0.0 )
{
speed = -speed;
}
double dist = speed * time_step;
double kts = speed * SG_METER_TO_NM * 3600.0;
_set_V_equiv_kts( kts );
_set_V_calibrated_kts( kts );
_set_V_ground_speed( kts );
// angle of turn
double turn_rate = globals->get_controls()->get_aileron() * SGD_PI_4; // radians/sec
double turn = turn_rate * time_step;
// update euler angles
_set_Euler_Angles( get_Phi(), get_Theta(),
fmod(get_Psi() + turn, SGD_2PI) );
_set_Euler_Rates(0,0,0);
// update (lon/lat) position
double lat2, lon2, az2;
if ( fabs( speed ) > SG_EPSILON ) {
geo_direct_wgs_84 ( get_Altitude(),
get_Latitude() * SGD_RADIANS_TO_DEGREES,
get_Longitude() * SGD_RADIANS_TO_DEGREES,
get_Psi() * SGD_RADIANS_TO_DEGREES,
dist, &lat2, &lon2, &az2 );
_set_Longitude( lon2 * SGD_DEGREES_TO_RADIANS );
_set_Latitude( lat2 * SGD_DEGREES_TO_RADIANS );
}
// cout << "lon error = " << fabs(end.x()*SGD_RADIANS_TO_DEGREES - lon2)
// << " lat error = " << fabs(end.y()*SGD_RADIANS_TO_DEGREES - lat2)
// << endl;
double sl_radius, lat_geoc;
sgGeodToGeoc( get_Latitude(), get_Altitude(), &sl_radius, &lat_geoc );
// update altitude
double real_climb_rate = -globals->get_controls()->get_elevator() * 5000; // feet/sec
_set_Climb_Rate( real_climb_rate / 500.0 );
double climb = real_climb_rate * time_step;
_set_Geocentric_Position( lat_geoc, get_Longitude(),
sl_radius + get_Altitude() + climb );
// cout << "sea level radius (ft) = " << sl_radius << endl;
// cout << "(setto) sea level radius (ft) = " << get_Sea_level_radius() << endl;
_update_ground_elev_at_pos();
_set_Sea_level_radius( sl_radius * SG_METER_TO_FEET);
_set_Altitude( get_Altitude() + climb );
}

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// MagicCarpet.hxx -- interface to the "Magic Carpet" flight model
//
// Written by Curtis Olson, started October 1999.
//
// Copyright (C) 1999 Curtis L. Olson - http://www.flightgear.org/~curt
//
// 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// $Id$
#ifndef _MAGICCARPET_HXX
#define _MAGICCARPET_HXX
#include <FDM/flight.hxx>
class FGMagicCarpet: public FGInterface {
public:
FGMagicCarpet( double dt );
~FGMagicCarpet();
// reset flight params to a specific position
void init();
// update position based on inputs, positions, velocities, etc.
void update( double dt );
};
#endif // _MAGICCARPET_HXX