--- /dev/null
+/*****************************************************************************
+
+ 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;
+}
+
+
--- /dev/null
+/*****************************************************************************
+
+ 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*/
+
+
+
+
--- /dev/null
+/*****************************************************************************
+
+ 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);
+ }
+
+ }
+}
+*/
--- /dev/null
+/*****************************************************************************
+
+ 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*/
--- /dev/null
+// 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 );
+}
--- /dev/null
+// 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
projects / flightgear.git / commitdiff