src/FDM/JSBSim/JSBSim.cxx

   1 // JSBsim.cxx -- interface to the JSBsim flight model
   2 //
   3 // Written by Curtis Olson, started February 1999.
   4 //
   5 // Copyright (C) 1999  Curtis L. Olson  - curt@flightgear.org
   6 //
   7 // This program is free software; you can redistribute it and/or
   8 // modify it under the terms of the GNU Lesser General Public License as
   9 // published by the Free Software Foundation; either version 2 of the
  10 // License, or (at your option) any later version.
  11 //
  12 // This program is distributed in the hope that it will be useful, but
  13 // WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 // Lesser General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU Lesser General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 //
  21 // $Id: JSBSim.cxx,v 1.64 2010/10/31 04:49:25 jberndt Exp $
  22
  23
  24 #ifdef HAVE_CONFIG_H
  25 #  include <config.h>
  26 #endif
  27
  28 #include <simgear/compiler.h>
  29
  30 #include <stdio.h>    //    size_t
  31 #include <string>
  32
  33 #include <simgear/constants.h>
  34 #include <simgear/debug/logstream.hxx>
  35 #include <simgear/math/sg_geodesy.hxx>
  36 #include <simgear/misc/sg_path.hxx>
  37 #include <simgear/structure/commands.hxx>
  38
  39 #include <FDM/flight.hxx>
  40
  41 #include <Aircraft/controls.hxx>
  42 #include <Main/globals.hxx>
  43 #include <Main/fg_props.hxx>
  44
  45 #include "JSBSim.hxx"
  46 #include <FDM/JSBSim/FGFDMExec.h>
  47 #include <FDM/JSBSim/FGJSBBase.h>
  48 #include <FDM/JSBSim/initialization/FGInitialCondition.h>
  49 #include <FDM/JSBSim/initialization/FGTrim.h>
  50 #include <FDM/JSBSim/models/FGModel.h>
  51 #include <FDM/JSBSim/models/FGAircraft.h>
  52 #include <FDM/JSBSim/models/FGFCS.h>
  53 #include <FDM/JSBSim/models/FGPropagate.h>
  54 #include <FDM/JSBSim/models/FGAuxiliary.h>
  55 #include <FDM/JSBSim/models/FGInertial.h>
  56 #include <FDM/JSBSim/models/FGAtmosphere.h>
  57 #include <FDM/JSBSim/models/FGMassBalance.h>
  58 #include <FDM/JSBSim/models/FGAerodynamics.h>
  59 #include <FDM/JSBSim/models/FGLGear.h>
  60 #include <FDM/JSBSim/models/FGGroundReactions.h>
  61 #include <FDM/JSBSim/models/FGPropulsion.h>
  62 #include <FDM/JSBSim/models/propulsion/FGEngine.h>
  63 #include <FDM/JSBSim/models/propulsion/FGPiston.h>
  64 #include <FDM/JSBSim/models/propulsion/FGTurbine.h>
  65 #include <FDM/JSBSim/models/propulsion/FGTurboProp.h>
  66 #include <FDM/JSBSim/models/propulsion/FGRocket.h>
  67 #include <FDM/JSBSim/models/propulsion/FGElectric.h>
  68 #include <FDM/JSBSim/models/propulsion/FGNozzle.h>
  69 #include <FDM/JSBSim/models/propulsion/FGPropeller.h>
  70 #include <FDM/JSBSim/models/propulsion/FGRotor.h>
  71 #include <FDM/JSBSim/models/propulsion/FGTank.h>
  72 #include <FDM/JSBSim/input_output/FGPropertyManager.h>
  73 #include <FDM/JSBSim/input_output/FGGroundCallback.h>
  74
  75 using namespace JSBSim;
  76
  77 static inline double
  78 FMAX (double a, double b)
  79 {
  80   return a > b ? a : b;
  81 }
  82
  83 class FGFSGroundCallback : public FGGroundCallback {
  84 public:
  85   FGFSGroundCallback(FGJSBsim* ifc) : mInterface(ifc) {}
  86   virtual ~FGFSGroundCallback() {}
  87
  88   /** Get the altitude above sea level dependent on the location. */
  89   virtual double GetAltitude(const FGLocation& l) const {
  90     double pt[3] = { SG_FEET_TO_METER*l(eX),
  91                      SG_FEET_TO_METER*l(eY),
  92                      SG_FEET_TO_METER*l(eZ) };
  93     double lat, lon, alt;
  94     sgCartToGeod( pt, &lat, &lon, &alt);
  95     return alt * SG_METER_TO_FEET;
  96   }
  97
  98   /** Compute the altitude above ground. */
  99   virtual double GetAGLevel(double t, const FGLocation& l,
 100                             FGLocation& cont, FGColumnVector3& n,
 101                             FGColumnVector3& v, FGColumnVector3& w) const {
 102     double loc_cart[3] = { l(eX), l(eY), l(eZ) };
 103     double contact[3], normal[3], vel[3], angularVel[3], agl = 0;
 104     mInterface->get_agl_ft(t, loc_cart, SG_METER_TO_FEET*2, contact, normal,
 105                            vel, angularVel, &agl);
 106     n = FGColumnVector3( normal[0], normal[1], normal[2] );
 107     v = FGColumnVector3( vel[0], vel[1], vel[2] );
 108     w = FGColumnVector3( angularVel[0], angularVel[1], angularVel[2] );
 109     cont = FGColumnVector3( contact[0], contact[1], contact[2] );
 110     return agl;
 111   }
 112 private:
 113   FGJSBsim* mInterface;
 114 };
 115
 116 /******************************************************************************/
 117
 118 FGJSBsim::FGJSBsim( double dt )
 119   : FGInterface(dt), got_wire(false)
 120 {
 121     bool result;
 122                                 // Set up the debugging level
 123                                 // FIXME: this will not respond to
 124                                 // runtime changes
 125
 126                                 // if flight is excluded, don't bother
 127     if ((logbuf::get_log_classes() & SG_FLIGHT) != 0) {
 128
 129                                 // do a rough-and-ready mapping to
 130                                 // the levels documented in FGFDMExec.h
 131         switch (logbuf::get_log_priority()) {
 132         case SG_BULK:
 133             FGJSBBase::debug_lvl = 0x1f;
 134             break;
 135         case SG_DEBUG:
 136             FGJSBBase::debug_lvl = 0x0f;
 137         case SG_INFO:
 138             FGJSBBase::debug_lvl = 0x01;
 139             break;
 140         case SG_WARN:
 141         case SG_ALERT:
 142             FGJSBBase::debug_lvl = 0x00;
 143             break;
 144         }
 145     }
 146
 147     fdmex = new FGFDMExec( (FGPropertyManager*)globals->get_props() );
 148
 149     // Register ground callback.
 150     fdmex->SetGroundCallback( new FGFSGroundCallback(this) );
 151
 152     Atmosphere      = fdmex->GetAtmosphere();
 153     FCS             = fdmex->GetFCS();
 154     MassBalance     = fdmex->GetMassBalance();
 155     Propulsion      = fdmex->GetPropulsion();
 156     Aircraft        = fdmex->GetAircraft();
 157     Propagate        = fdmex->GetPropagate();
 158     Auxiliary       = fdmex->GetAuxiliary();
 159     Inertial        = fdmex->GetInertial();
 160     Aerodynamics    = fdmex->GetAerodynamics();
 161     GroundReactions = fdmex->GetGroundReactions();
 162
 163     fgic=fdmex->GetIC();
 164     needTrim=true;
 165
 166     SGPath aircraft_path( fgGetString("/sim/aircraft-dir") );
 167
 168     SGPath engine_path( fgGetString("/sim/aircraft-dir") );
 169     engine_path.append( "Engine" );
 170
 171     SGPath systems_path( fgGetString("/sim/aircraft-dir") );
 172     systems_path.append( "Systems" );
 173
 174 // deprecate sim-time-sec for simulation/sim-time-sec
 175 // remove alias with increased configuration file version number (2.1 or later)
 176     SGPropertyNode * node = fgGetNode("/fdm/jsbsim/simulation/sim-time-sec");
 177     fgGetNode("/fdm/jsbsim/sim-time-sec", true)->alias( node );
 178 // end of sim-time-sec deprecation patch
 179
 180     fdmex->Setdt( dt );
 181
 182     result = fdmex->LoadModel( aircraft_path.str(),
 183                                engine_path.str(),
 184                                systems_path.str(),
 185                                fgGetString("/sim/aero"), false );
 186
 187     if (result) {
 188       SG_LOG( SG_FLIGHT, SG_INFO, "  loaded aero.");
 189     } else {
 190       SG_LOG( SG_FLIGHT, SG_INFO,
 191               "  aero does not exist (you may have mis-typed the name).");
 192       throw(-1);
 193     }
 194
 195     SG_LOG( SG_FLIGHT, SG_INFO, "" );
 196     SG_LOG( SG_FLIGHT, SG_INFO, "" );
 197     SG_LOG( SG_FLIGHT, SG_INFO, "After loading aero definition file ..." );
 198
 199     int Neng = Propulsion->GetNumEngines();
 200     SG_LOG( SG_FLIGHT, SG_INFO, "num engines = " << Neng );
 201
 202     if ( GroundReactions->GetNumGearUnits() <= 0 ) {
 203         SG_LOG( SG_FLIGHT, SG_ALERT, "num gear units = "
 204                 << GroundReactions->GetNumGearUnits() );
 205         SG_LOG( SG_FLIGHT, SG_ALERT, "This is a very bad thing because with 0 gear units, the ground trimming");
 206         SG_LOG( SG_FLIGHT, SG_ALERT, "routine (coming up later in the code) will core dump.");
 207         SG_LOG( SG_FLIGHT, SG_ALERT, "Halting the sim now, and hoping a solution will present itself soon!");
 208         exit(-1);
 209     }
 210
 211     init_gear();
 212
 213     // Set initial fuel levels if provided.
 214     for (unsigned int i = 0; i < Propulsion->GetNumTanks(); i++) {
 215       double d;
 216       SGPropertyNode * node = fgGetNode("/consumables/fuel/tank", i, true);
 217       FGTank* tank = Propulsion->GetTank(i);
 218
 219       d = node->getNode( "density-ppg", true )->getDoubleValue();
 220       if( d > 0.0 )
 221         tank->SetDensity( d );
 222
 223       d = node->getNode( "level-lbs", true )->getDoubleValue();
 224       if( d > 0.0 )
 225         tank->SetContents( d );
 226     }
 227     Propulsion->SetFuelFreeze((fgGetNode("/sim/freeze/fuel",true))->getBoolValue());
 228
 229     fgSetDouble("/fdm/trim/pitch-trim", FCS->GetPitchTrimCmd());
 230     fgSetDouble("/fdm/trim/throttle",   FCS->GetThrottleCmd(0));
 231     fgSetDouble("/fdm/trim/aileron",    FCS->GetDaCmd());
 232     fgSetDouble("/fdm/trim/rudder",     FCS->GetDrCmd());
 233
 234     startup_trim = fgGetNode("/sim/presets/trim", true);
 235
 236     trimmed = fgGetNode("/fdm/trim/trimmed", true);
 237     trimmed->setBoolValue(false);
 238
 239     pitch_trim = fgGetNode("/fdm/trim/pitch-trim", true );
 240     throttle_trim = fgGetNode("/fdm/trim/throttle", true );
 241     aileron_trim = fgGetNode("/fdm/trim/aileron", true );
 242     rudder_trim = fgGetNode("/fdm/trim/rudder", true );
 243
 244     stall_warning = fgGetNode("/sim/alarms/stall-warning",true);
 245     stall_warning->setDoubleValue(0);
 246
 247
 248     flap_pos_pct=fgGetNode("/surface-positions/flap-pos-norm",true);
 249     elevator_pos_pct=fgGetNode("/surface-positions/elevator-pos-norm",true);
 250     left_aileron_pos_pct
 251         =fgGetNode("/surface-positions/left-aileron-pos-norm",true);
 252     right_aileron_pos_pct
 253         =fgGetNode("/surface-positions/right-aileron-pos-norm",true);
 254     rudder_pos_pct=fgGetNode("/surface-positions/rudder-pos-norm",true);
 255     speedbrake_pos_pct
 256         =fgGetNode("/surface-positions/speedbrake-pos-norm",true);
 257     spoilers_pos_pct=fgGetNode("/surface-positions/spoilers-pos-norm",true);
 258     tailhook_pos_pct=fgGetNode("/gear/tailhook/position-norm",true);
 259     wing_fold_pos_pct=fgGetNode("surface-positions/wing-fold-pos-norm",true);
 260
 261     elevator_pos_pct->setDoubleValue(0);
 262     left_aileron_pos_pct->setDoubleValue(0);
 263     right_aileron_pos_pct->setDoubleValue(0);
 264     rudder_pos_pct->setDoubleValue(0);
 265     flap_pos_pct->setDoubleValue(0);
 266     speedbrake_pos_pct->setDoubleValue(0);
 267     spoilers_pos_pct->setDoubleValue(0);
 268
 269     ab_brake_engaged = fgGetNode("/autopilot/autobrake/engaged", true);
 270     ab_brake_left_pct = fgGetNode("/autopilot/autobrake/brake-left-output", true);
 271     ab_brake_right_pct = fgGetNode("/autopilot/autobrake/brake-right-output", true);
 272
 273     temperature = fgGetNode("/environment/temperature-degc",true);
 274     pressure = fgGetNode("/environment/pressure-inhg",true);
 275     density = fgGetNode("/environment/density-slugft3",true);
 276     turbulence_gain = fgGetNode("/environment/turbulence/magnitude-norm",true);
 277     turbulence_rate = fgGetNode("/environment/turbulence/rate-hz",true);
 278
 279     wind_from_north= fgGetNode("/environment/wind-from-north-fps",true);
 280     wind_from_east = fgGetNode("/environment/wind-from-east-fps" ,true);
 281     wind_from_down = fgGetNode("/environment/wind-from-down-fps" ,true);
 282
 283     slaved = fgGetNode("/sim/slaved/enabled", true);
 284
 285     for (unsigned int i = 0; i < Propulsion->GetNumEngines(); i++) {
 286       SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 287       Propulsion->GetEngine(i)->GetThruster()->SetRPM(node->getDoubleValue("rpm") /
 288                      Propulsion->GetEngine(i)->GetThruster()->GetGearRatio());
 289     }
 290
 291     hook_root_struct = FGColumnVector3(
 292         fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-offset-x-in", 196),
 293         fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-offset-y-in", 0),
 294         fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-offset-z-in", -16));
 295     last_hook_tip[0] = 0; last_hook_tip[1] = 0; last_hook_tip[2] = 0;
 296     last_hook_root[0] = 0; last_hook_root[1] = 0; last_hook_root[2] = 0;
 297
 298     crashed = false;
 299 }
 300
 301 /******************************************************************************/
 302 FGJSBsim::~FGJSBsim(void)
 303 {
 304   delete fdmex;
 305 }
 306
 307 /******************************************************************************/
 308
 309 // Initialize the JSBsim flight model, dt is the time increment for
 310 // each subsequent iteration through the EOM
 311
 312 void FGJSBsim::init()
 313 {
 314     SG_LOG( SG_FLIGHT, SG_INFO, "Starting and initializing JSBsim" );
 315
 316     // Explicitly call the superclass's
 317     // init method first.
 318
 319     if (fgGetBool("/environment/params/control-fdm-atmosphere")) {
 320       Atmosphere->UseExternal();
 321       Atmosphere->SetExTemperature(
 322                   9.0/5.0*(temperature->getDoubleValue()+273.15) );
 323       Atmosphere->SetExPressure(pressure->getDoubleValue()*70.726566);
 324       Atmosphere->SetExDensity(density->getDoubleValue());
 325       Atmosphere->SetTurbType(FGAtmosphere::ttCulp);
 326       Atmosphere->SetTurbGain(turbulence_gain->getDoubleValue());
 327       Atmosphere->SetTurbRate(turbulence_rate->getDoubleValue());
 328
 329     } else {
 330       Atmosphere->UseInternal();
 331     }
 332
 333     fgic->SetVNorthFpsIC( -wind_from_north->getDoubleValue() );
 334     fgic->SetVEastFpsIC( -wind_from_east->getDoubleValue() );
 335     fgic->SetVDownFpsIC( -wind_from_down->getDoubleValue() );
 336
 337     //Atmosphere->SetExTemperature(get_Static_temperature());
 338     //Atmosphere->SetExPressure(get_Static_pressure());
 339     //Atmosphere->SetExDensity(get_Density());
 340     SG_LOG(SG_FLIGHT,SG_INFO,"T,p,rho: " << fdmex->GetAtmosphere()->GetTemperature()
 341      << ", " << fdmex->GetAtmosphere()->GetPressure()
 342      << ", " << fdmex->GetAtmosphere()->GetDensity() );
 343
 344 // deprecate egt_degf for egt-degf to have consistent naming
 345 // TODO: raise log-level to ALERT in summer 2010,
 346 // remove alias in fall 2010,
 347 // remove this code in winter 2010
 348     for (unsigned int i=0; i < Propulsion->GetNumEngines(); i++) {
 349       SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 350       SGPropertyNode * egtn = node->getNode( "egt_degf" );
 351       if( egtn != NULL ) {
 352         SG_LOG(SG_FLIGHT,SG_WARN,
 353                "Aircraft uses deprecated node egt_degf. Please upgrade to egt-degf");
 354         node->getNode("egt-degf", true)->alias( egtn );
 355       }
 356     }
 357 // end of egt_degf deprecation patch
 358
 359     if (fgGetBool("/sim/presets/running")) {
 360           for (unsigned int i=0; i < Propulsion->GetNumEngines(); i++) {
 361             SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 362             node->setBoolValue("running", true);
 363             Propulsion->GetEngine(i)->SetRunning(true);
 364           }
 365     }
 366
 367     FCS->SetDfPos( ofNorm, globals->get_controls()->get_flaps() );
 368
 369     common_init();
 370
 371     copy_to_JSBsim();
 372     fdmex->RunIC();     //loop JSBSim once w/o integrating
 373     copy_from_JSBsim(); //update the bus
 374
 375     SG_LOG( SG_FLIGHT, SG_INFO, "  Initialized JSBSim with:" );
 376
 377     switch(fgic->GetSpeedSet()) {
 378     case setned:
 379         SG_LOG(SG_FLIGHT,SG_INFO, "  Vn,Ve,Vd= "
 380                << Propagate->GetVel(FGJSBBase::eNorth) << ", "
 381                << Propagate->GetVel(FGJSBBase::eEast) << ", "
 382                << Propagate->GetVel(FGJSBBase::eDown) << " ft/s");
 383     break;
 384     case setuvw:
 385         SG_LOG(SG_FLIGHT,SG_INFO, "  U,V,W= "
 386                << Propagate->GetUVW(1) << ", "
 387                << Propagate->GetUVW(2) << ", "
 388                << Propagate->GetUVW(3) << " ft/s");
 389     break;
 390     case setmach:
 391         SG_LOG(SG_FLIGHT,SG_INFO, "  Mach: "
 392                << Auxiliary->GetMach() );
 393     break;
 394     case setvc:
 395     default:
 396         SG_LOG(SG_FLIGHT,SG_INFO, "  Indicated Airspeed: "
 397                << Auxiliary->GetVcalibratedKTS() << " knots" );
 398     break;
 399     }
 400
 401     stall_warning->setDoubleValue(0);
 402
 403     SG_LOG( SG_FLIGHT, SG_INFO, "  Bank Angle: "
 404             << Propagate->GetEuler(FGJSBBase::ePhi)*RADTODEG << " deg" );
 405     SG_LOG( SG_FLIGHT, SG_INFO, "  Pitch Angle: "
 406             << Propagate->GetEuler(FGJSBBase::eTht)*RADTODEG << " deg" );
 407     SG_LOG( SG_FLIGHT, SG_INFO, "  True Heading: "
 408             << Propagate->GetEuler(FGJSBBase::ePsi)*RADTODEG << " deg" );
 409     SG_LOG( SG_FLIGHT, SG_INFO, "  Latitude: "
 410             << Propagate->GetLocation().GetLatitudeDeg() << " deg" );
 411     SG_LOG( SG_FLIGHT, SG_INFO, "  Longitude: "
 412             << Propagate->GetLocation().GetLongitudeDeg() << " deg" );
 413     SG_LOG( SG_FLIGHT, SG_INFO, "  Altitude: "
 414             << Propagate->GetAltitudeASL() << " feet" );
 415     SG_LOG( SG_FLIGHT, SG_INFO, "  loaded initial conditions" );
 416
 417     SG_LOG( SG_FLIGHT, SG_INFO, "  set dt" );
 418
 419     SG_LOG( SG_FLIGHT, SG_INFO, "Finished initializing JSBSim" );
 420
 421     SG_LOG( SG_FLIGHT, SG_INFO, "FGControls::get_gear_down()= " <<
 422                                   globals->get_controls()->get_gear_down() );
 423 }
 424
 425 /******************************************************************************/
 426
 427 void FGJSBsim::unbind()
 428 {
 429   fdmex->Unbind();
 430   FGInterface::unbind();
 431 }
 432
 433 /******************************************************************************/
 434
 435 // Run an iteration of the EOM (equations of motion)
 436
 437 void FGJSBsim::update( double dt )
 438 {
 439     if(crashed) {
 440       if(!fgGetBool("/sim/crashed"))
 441         fgSetBool("/sim/crashed", true);
 442       return;
 443     }
 444
 445     if (is_suspended())
 446       return;
 447
 448     int multiloop = _calc_multiloop(dt);
 449
 450     int i;
 451
 452     // Compute the radius of the aircraft. That is the radius of a ball
 453     // where all gear units are in. At the moment it is at least 10ft ...
 454     double acrad = 10.0;
 455     int n_gears = GroundReactions->GetNumGearUnits();
 456     for (i=0; i<n_gears; ++i) {
 457       FGColumnVector3 bl = GroundReactions->GetGearUnit(i)->GetBodyLocation();
 458       double r = bl.Magnitude();
 459       if (acrad < r)
 460         acrad = r;
 461     }
 462
 463     // Compute the potential movement of this aircraft and query for the
 464     // ground in this area.
 465     double groundCacheRadius = acrad + 2*dt*Propagate->GetUVW().Magnitude();
 466     double alt, slr, lat, lon;
 467     FGLocation cart = Auxiliary->GetLocationVRP();
 468     if ( needTrim && startup_trim->getBoolValue() ) {
 469       alt = fgic->GetAltitudeASLFtIC();
 470       slr = fgic->GetSeaLevelRadiusFtIC();
 471       lat = fgic->GetLatitudeDegIC() * SGD_DEGREES_TO_RADIANS;
 472       lon = fgic->GetLongitudeDegIC() * SGD_DEGREES_TO_RADIANS;
 473       cart = FGLocation(lon, lat, alt+slr);
 474     }
 475     double cart_pos[3] = { cart(1), cart(2), cart(3) };
 476     double t0 = fdmex->GetSimTime();
 477     bool cache_ok = prepare_ground_cache_ft( t0, t0 + dt, cart_pos,
 478                                              groundCacheRadius );
 479     if (!cache_ok) {
 480       SG_LOG(SG_FLIGHT, SG_WARN,
 481              "FGInterface is being called without scenery below the aircraft!");
 482
 483       alt = fgic->GetAltitudeASLFtIC();
 484       SG_LOG(SG_FLIGHT, SG_WARN, "altitude         = " << alt);
 485
 486       slr = fgic->GetSeaLevelRadiusFtIC();
 487       SG_LOG(SG_FLIGHT, SG_WARN, "sea level radius = " << slr);
 488
 489       lat = fgic->GetLatitudeDegIC() * SGD_DEGREES_TO_RADIANS;
 490       SG_LOG(SG_FLIGHT, SG_WARN, "latitude         = " << lat);
 491
 492       lon = fgic->GetLongitudeDegIC() * SGD_DEGREES_TO_RADIANS;
 493       SG_LOG(SG_FLIGHT, SG_WARN, "longitude        = " << lon);
 494       //return;
 495     }
 496
 497     copy_to_JSBsim();
 498
 499     trimmed->setBoolValue(false);
 500
 501     if ( needTrim ) {
 502       if ( startup_trim->getBoolValue() ) {
 503         double contact[3], d[3], vel[3], agl;
 504         get_agl_ft(fdmex->GetSimTime(), cart_pos, SG_METER_TO_FEET*2, contact,
 505                    d, vel, d, &agl);
 506         double terrain_alt = sqrt(contact[0]*contact[0] + contact[1]*contact[1]
 507              + contact[2]*contact[2]) - fgic->GetSeaLevelRadiusFtIC();
 508
 509         SG_LOG(SG_FLIGHT, SG_INFO,
 510           "Ready to trim, terrain elevation is: "
 511             << terrain_alt * SG_METER_TO_FEET );
 512
 513         if (fgGetBool("/sim/presets/onground")) {
 514           FGColumnVector3 gndVelNED = cart.GetTec2l()
 515                                     * FGColumnVector3(vel[0], vel[1], vel[2]);
 516           fgic->SetVNorthFpsIC(gndVelNED(1));
 517           fgic->SetVEastFpsIC(gndVelNED(2));
 518           fgic->SetVDownFpsIC(gndVelNED(3));
 519         }
 520         fgic->SetTerrainElevationFtIC( terrain_alt );
 521         do_trim();
 522       } else {
 523         fdmex->RunIC();  //apply any changes made through the set_ functions
 524       }
 525       needTrim = false;
 526     }
 527
 528     for ( i=0; i < multiloop; i++ ) {
 529       fdmex->Run();
 530       update_external_forces(fdmex->GetSimTime() + i * fdmex->GetDeltaT());
 531     }
 532
 533     FGJSBBase::Message* msg;
 534     while (msg = fdmex->ProcessNextMessage()) {
 535 //      msg = fdmex->ProcessNextMessage();
 536       switch (msg->type) {
 537       case FGJSBBase::Message::eText:
 538         if (msg->text == "Crash Detected: Simulation FREEZE.")
 539           crashed = true;
 540         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text );
 541         break;
 542       case FGJSBBase::Message::eBool:
 543         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text << " " << msg->bVal );
 544         break;
 545       case FGJSBBase::Message::eInteger:
 546         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text << " " << msg->iVal );
 547         break;
 548       case FGJSBBase::Message::eDouble:
 549         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text << " " << msg->dVal );
 550         break;
 551       default:
 552         SG_LOG( SG_FLIGHT, SG_INFO, "Unrecognized message type." );
 553         break;
 554       }
 555     }
 556
 557     // translate JSBsim back to FG structure so that the
 558     // autopilot (and the rest of the sim can use the updated values
 559     copy_from_JSBsim();
 560 }
 561
 562 /******************************************************************************/
 563
 564 // Convert from the FGInterface struct to the JSBsim generic_ struct
 565
 566 bool FGJSBsim::copy_to_JSBsim()
 567 {
 568     double tmp;
 569     unsigned int i;
 570
 571     // copy control positions into the JSBsim structure
 572
 573     FCS->SetDaCmd( globals->get_controls()->get_aileron());
 574     FCS->SetRollTrimCmd( globals->get_controls()->get_aileron_trim() );
 575     FCS->SetDeCmd( globals->get_controls()->get_elevator());
 576     FCS->SetPitchTrimCmd( globals->get_controls()->get_elevator_trim() );
 577     FCS->SetDrCmd( -globals->get_controls()->get_rudder() );
 578     FCS->SetYawTrimCmd( -globals->get_controls()->get_rudder_trim() );
 579     FCS->SetDsCmd( globals->get_controls()->get_rudder() );
 580     FCS->SetDfCmd( globals->get_controls()->get_flaps() );
 581     FCS->SetDsbCmd( globals->get_controls()->get_speedbrake() );
 582     FCS->SetDspCmd( globals->get_controls()->get_spoilers() );
 583
 584         // Parking brake sets minimum braking
 585         // level for mains.
 586     double parking_brake = globals->get_controls()->get_brake_parking();
 587     double left_brake = globals->get_controls()->get_brake_left();
 588     double right_brake = globals->get_controls()->get_brake_right();
 589
 590     if (ab_brake_engaged->getBoolValue()) {
 591       left_brake = ab_brake_left_pct->getDoubleValue();
 592       right_brake = ab_brake_right_pct->getDoubleValue();
 593     }
 594
 595     FCS->SetLBrake(FMAX(left_brake, parking_brake));
 596     FCS->SetRBrake(FMAX(right_brake, parking_brake));
 597
 598
 599     FCS->SetCBrake( 0.0 );
 600     // FCS->SetCBrake( globals->get_controls()->get_brake(2) );
 601
 602     FCS->SetGearCmd( globals->get_controls()->get_gear_down());
 603     for (i = 0; i < Propulsion->GetNumEngines(); i++) {
 604       SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 605
 606       FCS->SetThrottleCmd(i, globals->get_controls()->get_throttle(i));
 607       FCS->SetMixtureCmd(i, globals->get_controls()->get_mixture(i));
 608       FCS->SetPropAdvanceCmd(i, globals->get_controls()->get_prop_advance(i));
 609       FCS->SetFeatherCmd(i, globals->get_controls()->get_feather(i));
 610
 611       switch (Propulsion->GetEngine(i)->GetType()) {
 612       case FGEngine::etPiston:
 613         { // FGPiston code block
 614         FGPiston* eng = (FGPiston*)Propulsion->GetEngine(i);
 615         eng->SetMagnetos( globals->get_controls()->get_magnetos(i) );
 616         break;
 617         } // end FGPiston code block
 618       case FGEngine::etTurbine:
 619         { // FGTurbine code block
 620         FGTurbine* eng = (FGTurbine*)Propulsion->GetEngine(i);
 621         eng->SetAugmentation( globals->get_controls()->get_augmentation(i) );
 622         eng->SetReverse( globals->get_controls()->get_reverser(i) );
 623         //eng->SetInjection( globals->get_controls()->get_water_injection(i) );
 624         eng->SetCutoff( globals->get_controls()->get_cutoff(i) );
 625         eng->SetIgnition( globals->get_controls()->get_ignition(i) );
 626         break;
 627         } // end FGTurbine code block
 628       case FGEngine::etRocket:
 629         { // FGRocket code block
 630         FGRocket* eng = (FGRocket*)Propulsion->GetEngine(i);
 631         break;
 632         } // end FGRocket code block
 633       case FGEngine::etTurboprop:
 634         { // FGTurboProp code block
 635         FGTurboProp* eng = (FGTurboProp*)Propulsion->GetEngine(i);
 636         eng->SetReverse( globals->get_controls()->get_reverser(i) );
 637         eng->SetCutoff( globals->get_controls()->get_cutoff(i) );
 638         eng->SetIgnition( globals->get_controls()->get_ignition(i) );
 639
 640         eng->SetGeneratorPower( globals->get_controls()->get_generator_breaker(i) );
 641         eng->SetCondition( globals->get_controls()->get_condition(i) );
 642         break;
 643         } // end FGTurboProp code block
 644       default:
 645         break;
 646       }
 647
 648       { // FGEngine code block
 649       FGEngine* eng = Propulsion->GetEngine(i);
 650
 651       eng->SetStarter( globals->get_controls()->get_starter(i) );
 652       eng->SetRunning( node->getBoolValue("running") );
 653       } // end FGEngine code block
 654     }
 655
 656
 657     Propagate->SetSeaLevelRadius( get_Sea_level_radius() );
 658
 659     Atmosphere->SetExTemperature(
 660                   9.0/5.0*(temperature->getDoubleValue()+273.15) );
 661     Atmosphere->SetExPressure(pressure->getDoubleValue()*70.726566);
 662     Atmosphere->SetExDensity(density->getDoubleValue());
 663
 664     tmp = turbulence_gain->getDoubleValue();
 665     //Atmosphere->SetTurbGain(tmp * tmp * 100.0);
 666
 667     tmp = turbulence_rate->getDoubleValue();
 668     //Atmosphere->SetTurbRate(tmp);
 669
 670     Atmosphere->SetWindNED( -wind_from_north->getDoubleValue(),
 671                             -wind_from_east->getDoubleValue(),
 672                             -wind_from_down->getDoubleValue() );
 673 //    SG_LOG(SG_FLIGHT,SG_INFO, "Wind NED: "
 674 //                  << get_V_north_airmass() << ", "
 675 //                  << get_V_east_airmass()  << ", "
 676 //                  << get_V_down_airmass() );
 677
 678     for (i = 0; i < Propulsion->GetNumTanks(); i++) {
 679       SGPropertyNode * node = fgGetNode("/consumables/fuel/tank", i, true);
 680       FGTank * tank = Propulsion->GetTank(i);
 681       double fuelDensity = node->getDoubleValue("density-ppg");
 682
 683       if (fuelDensity < 0.1)
 684         fuelDensity = 6.0; // Use average fuel value
 685
 686       tank->SetDensity(fuelDensity);
 687       tank->SetContents(node->getDoubleValue("level-lbs"));
 688     }
 689
 690     Propulsion->SetFuelFreeze((fgGetNode("/sim/freeze/fuel",true))->getBoolValue());
 691     fdmex->SetChild(slaved->getBoolValue());
 692
 693     return true;
 694 }
 695
 696 /******************************************************************************/
 697
 698 // Convert from the JSBsim generic_ struct to the FGInterface struct
 699
 700 bool FGJSBsim::copy_from_JSBsim()
 701 {
 702     unsigned int i, j;
 703 /*
 704     _set_Inertias( MassBalance->GetMass(),
 705                    MassBalance->GetIxx(),
 706                    MassBalance->GetIyy(),
 707                    MassBalance->GetIzz(),
 708                    MassBalance->GetIxz() );
 709 */
 710     _set_CG_Position( MassBalance->GetXYZcg(1),
 711                       MassBalance->GetXYZcg(2),
 712                       MassBalance->GetXYZcg(3) );
 713
 714     _set_Accels_Body( Aircraft->GetBodyAccel(1),
 715                       Aircraft->GetBodyAccel(2),
 716                       Aircraft->GetBodyAccel(3) );
 717
 718     _set_Accels_CG_Body_N ( Aircraft->GetNcg(1),
 719                             Aircraft->GetNcg(2),
 720                             Aircraft->GetNcg(3) );
 721
 722     _set_Accels_Pilot_Body( Auxiliary->GetPilotAccel(1),
 723                             Auxiliary->GetPilotAccel(2),
 724                             Auxiliary->GetPilotAccel(3) );
 725
 726     _set_Nlf( Aircraft->GetNlf() );
 727
 728     // Velocities
 729
 730     _set_Velocities_Local( Propagate->GetVel(FGJSBBase::eNorth),
 731                            Propagate->GetVel(FGJSBBase::eEast),
 732                            Propagate->GetVel(FGJSBBase::eDown) );
 733
 734     _set_Velocities_Wind_Body( Propagate->GetUVW(1),
 735                                Propagate->GetUVW(2),
 736                                Propagate->GetUVW(3) );
 737
 738     // Make the HUD work ...
 739     _set_Velocities_Ground( Propagate->GetVel(FGJSBBase::eNorth),
 740                             Propagate->GetVel(FGJSBBase::eEast),
 741                             -Propagate->GetVel(FGJSBBase::eDown) );
 742
 743     _set_V_rel_wind( Auxiliary->GetVt() );
 744
 745     _set_V_equiv_kts( Auxiliary->GetVequivalentKTS() );
 746
 747     _set_V_calibrated_kts( Auxiliary->GetVcalibratedKTS() );
 748
 749     _set_V_ground_speed( Auxiliary->GetVground() );
 750
 751     _set_Omega_Body( Propagate->GetPQR(FGJSBBase::eP),
 752                      Propagate->GetPQR(FGJSBBase::eQ),
 753                      Propagate->GetPQR(FGJSBBase::eR) );
 754
 755     _set_Euler_Rates( Auxiliary->GetEulerRates(FGJSBBase::ePhi),
 756                       Auxiliary->GetEulerRates(FGJSBBase::eTht),
 757                       Auxiliary->GetEulerRates(FGJSBBase::ePsi) );
 758
 759     _set_Mach_number( Auxiliary->GetMach() );
 760
 761     // Positions of Visual Reference Point
 762     FGLocation l = Auxiliary->GetLocationVRP();
 763     _updateGeocentricPosition( l.GetLatitude(), l.GetLongitude(),
 764                                l.GetRadius() - get_Sea_level_radius() );
 765
 766     _set_Altitude_AGL( Propagate->GetDistanceAGL() );
 767     {
 768       double loc_cart[3] = { l(FGJSBBase::eX), l(FGJSBBase::eY), l(FGJSBBase::eZ) };
 769       double contact[3], d[3], sd, t;
 770       is_valid_m(&t, d, &sd);
 771       get_agl_ft(t, loc_cart, SG_METER_TO_FEET*2, contact, d, d, d, &sd);
 772       double rwrad
 773         = FGColumnVector3( contact[0], contact[1], contact[2] ).Magnitude();
 774       _set_Runway_altitude( rwrad - get_Sea_level_radius() );
 775     }
 776
 777     _set_Euler_Angles( Propagate->GetEuler(FGJSBBase::ePhi),
 778                        Propagate->GetEuler(FGJSBBase::eTht),
 779                        Propagate->GetEuler(FGJSBBase::ePsi) );
 780
 781     _set_Alpha( Auxiliary->Getalpha() );
 782     _set_Beta( Auxiliary->Getbeta() );
 783
 784
 785     _set_Gamma_vert_rad( Auxiliary->GetGamma() );
 786
 787     _set_Earth_position_angle( Inertial->GetEarthPositionAngle() );
 788
 789     _set_Climb_Rate( Propagate->Gethdot() );
 790
 791     const FGMatrix33& Tl2b = Propagate->GetTl2b();
 792     for ( i = 1; i <= 3; i++ ) {
 793         for ( j = 1; j <= 3; j++ ) {
 794             _set_T_Local_to_Body( i, j, Tl2b(i,j) );
 795         }
 796     }
 797
 798     // Copy the engine values from JSBSim.
 799     for ( i=0; i < Propulsion->GetNumEngines(); i++ ) {
 800       SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 801       SGPropertyNode * tnode = node->getChild("thruster", 0, true);
 802       FGThruster * thruster = Propulsion->GetEngine(i)->GetThruster();
 803
 804       switch (Propulsion->GetEngine(i)->GetType()) {
 805       case FGEngine::etPiston:
 806         { // FGPiston code block
 807         FGPiston* eng = (FGPiston*)Propulsion->GetEngine(i);
 808         node->setDoubleValue("egt-degf", eng->getExhaustGasTemp_degF());
 809         node->setDoubleValue("oil-temperature-degf", eng->getOilTemp_degF());
 810         node->setDoubleValue("oil-pressure-psi", eng->getOilPressure_psi());
 811         node->setDoubleValue("mp-osi", eng->getManifoldPressure_inHg());
 812         // NOTE: mp-osi is not in ounces per square inch.
 813         // This error is left for reasons of backwards compatibility with
 814         // existing FlightGear sound and instrument configurations.
 815         node->setDoubleValue("mp-inhg", eng->getManifoldPressure_inHg());
 816         node->setDoubleValue("cht-degf", eng->getCylinderHeadTemp_degF());
 817         node->setDoubleValue("rpm", eng->getRPM());
 818         } // end FGPiston code block
 819         break;
 820       case FGEngine::etRocket:
 821         { // FGRocket code block
 822         FGRocket* eng = (FGRocket*)Propulsion->GetEngine(i);
 823         } // end FGRocket code block
 824         break;
 825       case FGEngine::etTurbine:
 826         { // FGTurbine code block
 827         FGTurbine* eng = (FGTurbine*)Propulsion->GetEngine(i);
 828         node->setDoubleValue("n1", eng->GetN1());
 829         node->setDoubleValue("n2", eng->GetN2());
 830         node->setDoubleValue("egt-degf", 32 + eng->GetEGT()*9/5);
 831         node->setBoolValue("augmentation", eng->GetAugmentation());
 832         node->setBoolValue("water-injection", eng->GetInjection());
 833         node->setBoolValue("ignition", eng->GetIgnition());
 834         node->setDoubleValue("nozzle-pos-norm", eng->GetNozzle());
 835         node->setDoubleValue("inlet-pos-norm", eng->GetInlet());
 836         node->setDoubleValue("oil-pressure-psi", eng->getOilPressure_psi());
 837         node->setBoolValue("reversed", eng->GetReversed());
 838         node->setBoolValue("cutoff", eng->GetCutoff());
 839         node->setDoubleValue("epr", eng->GetEPR());
 840         globals->get_controls()->set_reverser(i, eng->GetReversed() );
 841         globals->get_controls()->set_cutoff(i, eng->GetCutoff() );
 842         globals->get_controls()->set_water_injection(i, eng->GetInjection() );
 843         globals->get_controls()->set_augmentation(i, eng->GetAugmentation() );
 844         } // end FGTurbine code block
 845         break;
 846       case FGEngine::etTurboprop:
 847         { // FGTurboProp code block
 848         FGTurboProp* eng = (FGTurboProp*)Propulsion->GetEngine(i);
 849         node->setDoubleValue("n1", eng->GetN1());
 850         //node->setDoubleValue("n2", eng->GetN2());
 851         node->setDoubleValue("itt_degf", 32 + eng->GetITT()*9/5);
 852         node->setBoolValue("ignition", eng->GetIgnition());
 853         node->setDoubleValue("nozzle-pos-norm", eng->GetNozzle());
 854         node->setDoubleValue("inlet-pos-norm", eng->GetInlet());
 855         node->setDoubleValue("oil-pressure-psi", eng->getOilPressure_psi());
 856         node->setBoolValue("reversed", eng->GetReversed());
 857         node->setBoolValue("cutoff", eng->GetCutoff());
 858         node->setBoolValue("starting", eng->GetEngStarting());
 859         node->setBoolValue("generator-power", eng->GetGeneratorPower());
 860         node->setBoolValue("damaged", eng->GetCondition());
 861         node->setBoolValue("ielu-intervent", eng->GetIeluIntervent());
 862         node->setDoubleValue("oil-temperature-degf", eng->getOilTemp_degF());
 863 //        node->setBoolValue("onfire", eng->GetFire());
 864         globals->get_controls()->set_reverser(i, eng->GetReversed() );
 865         globals->get_controls()->set_cutoff(i, eng->GetCutoff() );
 866         } // end FGTurboProp code block
 867         break;
 868       case FGEngine::etElectric:
 869         { // FGElectric code block
 870         FGElectric* eng = (FGElectric*)Propulsion->GetEngine(i);
 871         node->setDoubleValue("rpm", eng->getRPM());
 872         } // end FGElectric code block
 873         break;
 874       case FGEngine::etUnknown:
 875         break;
 876       }
 877
 878       { // FGEngine code block
 879       FGEngine* eng = Propulsion->GetEngine(i);
 880       node->setDoubleValue("fuel-flow-gph", eng->getFuelFlow_gph());
 881       node->setDoubleValue("thrust_lb", thruster->GetThrust());
 882       node->setDoubleValue("fuel-flow_pph", eng->getFuelFlow_pph());
 883       node->setBoolValue("running", eng->GetRunning());
 884       node->setBoolValue("starter", eng->GetStarter());
 885       node->setBoolValue("cranking", eng->GetCranking());
 886       globals->get_controls()->set_starter(i, eng->GetStarter() );
 887       } // end FGEngine code block
 888
 889       switch (thruster->GetType()) {
 890       case FGThruster::ttNozzle:
 891         { // FGNozzle code block
 892         FGNozzle* noz = (FGNozzle*)thruster;
 893         } // end FGNozzle code block
 894         break;
 895       case FGThruster::ttPropeller:
 896         { // FGPropeller code block
 897         FGPropeller* prop = (FGPropeller*)thruster;
 898         tnode->setDoubleValue("rpm", thruster->GetRPM());
 899         tnode->setDoubleValue("pitch", prop->GetPitch());
 900         tnode->setDoubleValue("torque", prop->GetTorque());
 901         tnode->setBoolValue("feathered", prop->GetFeather());
 902         } // end FGPropeller code block
 903         break;
 904       case FGThruster::ttRotor:
 905         { // FGRotor code block
 906         FGRotor* rotor = (FGRotor*)thruster;
 907         } // end FGRotor code block
 908         break;
 909       case FGThruster::ttDirect:
 910         { // Direct code block
 911         } // end Direct code block
 912         break;
 913       }
 914
 915     }
 916
 917     // Copy the fuel levels from JSBSim if fuel
 918     // freeze not enabled.
 919     if ( ! Propulsion->GetFuelFreeze() ) {
 920       for (i = 0; i < Propulsion->GetNumTanks(); i++) {
 921         SGPropertyNode * node = fgGetNode("/consumables/fuel/tank", i, true);
 922         FGTank* tank = Propulsion->GetTank(i);
 923         double contents = tank->GetContents();
 924         double temp = tank->GetTemperature_degC();
 925         double fuelDensity = tank->GetDensity();
 926
 927         if (fuelDensity < 0.1)
 928           fuelDensity = 6.0; // Use average fuel value
 929
 930         node->setDoubleValue("density-ppg" , fuelDensity);
 931         node->setDoubleValue("level-lbs", contents);
 932         if (temp != -9999.0) node->setDoubleValue("temperature_degC", temp);
 933       }
 934     }
 935
 936     update_gear();
 937
 938     stall_warning->setDoubleValue( Aerodynamics->GetStallWarn() );
 939
 940     elevator_pos_pct->setDoubleValue( FCS->GetDePos(ofNorm) );
 941     left_aileron_pos_pct->setDoubleValue( FCS->GetDaLPos(ofNorm) );
 942     right_aileron_pos_pct->setDoubleValue( FCS->GetDaRPos(ofNorm) );
 943     rudder_pos_pct->setDoubleValue( -1*FCS->GetDrPos(ofNorm) );
 944     flap_pos_pct->setDoubleValue( FCS->GetDfPos(ofNorm) );
 945     speedbrake_pos_pct->setDoubleValue( FCS->GetDsbPos(ofNorm) );
 946     spoilers_pos_pct->setDoubleValue( FCS->GetDspPos(ofNorm) );
 947     tailhook_pos_pct->setDoubleValue( FCS->GetTailhookPos() );
 948     wing_fold_pos_pct->setDoubleValue( FCS->GetWingFoldPos() );
 949
 950     // force a sim crashed if crashed (altitude AGL < 0)
 951     if (get_Altitude_AGL() < -100.0) {
 952          fdmex->SuspendIntegration();
 953          crashed = true;
 954     }
 955
 956     return true;
 957 }
 958
 959
 960 bool FGJSBsim::ToggleDataLogging(void)
 961 {
 962   // ToDo: handle this properly
 963   fdmex->DisableOutput();
 964   return false;
 965 }
 966
 967
 968 bool FGJSBsim::ToggleDataLogging(bool state)
 969 {
 970     if (state) {
 971       fdmex->EnableOutput();
 972       return true;
 973     } else {
 974       fdmex->DisableOutput();
 975       return false;
 976     }
 977 }
 978
 979
 980 //Positions
 981 void FGJSBsim::set_Latitude(double lat)
 982 {
 983     static SGConstPropertyNode_ptr altitude = fgGetNode("/position/altitude-ft");
 984     double alt;
 985     double sea_level_radius_meters, lat_geoc;
 986
 987     // In case we're not trimming
 988     FGInterface::set_Latitude(lat);
 989
 990     if ( altitude->getDoubleValue() > -9990 ) {
 991       alt = altitude->getDoubleValue();
 992     } else {
 993       alt = 0.0;
 994     }
 995
 996     update_ic();
 997     SG_LOG(SG_FLIGHT,SG_INFO,"FGJSBsim::set_Latitude: " << lat );
 998     SG_LOG(SG_FLIGHT,SG_INFO," cur alt (ft) =  " << alt );
 999
1000     sgGeodToGeoc( lat, alt * SG_FEET_TO_METER,
1001                       &sea_level_radius_meters, &lat_geoc );
1002     _set_Sea_level_radius( sea_level_radius_meters * SG_METER_TO_FEET  );
1003     fgic->SetSeaLevelRadiusFtIC( sea_level_radius_meters * SG_METER_TO_FEET  );
1004     fgic->SetLatitudeRadIC( lat_geoc );
1005     needTrim=true;
1006 }
1007
1008
1009 void FGJSBsim::set_Longitude(double lon)
1010 {
1011     SG_LOG(SG_FLIGHT,SG_INFO,"FGJSBsim::set_Longitude: " << lon );
1012
1013     // In case we're not trimming
1014     FGInterface::set_Longitude(lon);
1015
1016     update_ic();
1017     fgic->SetLongitudeRadIC( lon );
1018     needTrim=true;
1019 }
1020
1021 // Sets the altitude above sea level.
1022 void FGJSBsim::set_Altitude(double alt)
1023 {
1024     static SGConstPropertyNode_ptr latitude = fgGetNode("/position/latitude-deg");
1025
1026     double sea_level_radius_meters,lat_geoc;
1027
1028     SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Altitude: " << alt );
1029     SG_LOG(SG_FLIGHT,SG_INFO, "  lat (deg) = " << latitude->getDoubleValue() );
1030
1031     // In case we're not trimming
1032     FGInterface::set_Altitude(alt);
1033
1034     update_ic();
1035     sgGeodToGeoc( latitude->getDoubleValue() * SGD_DEGREES_TO_RADIANS, alt,
1036                   &sea_level_radius_meters, &lat_geoc);
1037     _set_Sea_level_radius( sea_level_radius_meters * SG_METER_TO_FEET  );
1038     fgic->SetSeaLevelRadiusFtIC( sea_level_radius_meters * SG_METER_TO_FEET );
1039     SG_LOG(SG_FLIGHT, SG_INFO,
1040           "Terrain elevation: " << FGInterface::get_Runway_altitude() * SG_METER_TO_FEET );
1041     fgic->SetLatitudeRadIC( lat_geoc );
1042     fgic->SetAltitudeASLFtIC(alt);
1043     needTrim=true;
1044 }
1045
1046 void FGJSBsim::set_V_calibrated_kts(double vc)
1047 {
1048     SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_V_calibrated_kts: " <<  vc );
1049
1050     // In case we're not trimming
1051     FGInterface::set_V_calibrated_kts(vc);
1052
1053     update_ic();
1054     fgic->SetVcalibratedKtsIC(vc);
1055     needTrim=true;
1056 }
1057
1058 void FGJSBsim::set_Mach_number(double mach)
1059 {
1060     SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Mach_number: " <<  mach );
1061
1062     // In case we're not trimming
1063     FGInterface::set_Mach_number(mach);
1064
1065     update_ic();
1066     fgic->SetMachIC(mach);
1067     needTrim=true;
1068 }
1069
1070 void FGJSBsim::set_Velocities_Local( double north, double east, double down )
1071 {
1072     SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Velocities_Local: "
1073        << north << ", " <<  east << ", " << down );
1074
1075     // In case we're not trimming
1076     FGInterface::set_Velocities_Local(north, east, down);
1077
1078     update_ic();
1079     fgic->SetVNorthFpsIC(north);
1080     fgic->SetVEastFpsIC(east);
1081     fgic->SetVDownFpsIC(down);
1082     needTrim=true;
1083 }
1084
1085 void FGJSBsim::set_Velocities_Wind_Body( double u, double v, double w)
1086 {
1087     SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Velocities_Wind_Body: "
1088        << u << ", " <<  v << ", " <<  w );
1089
1090     // In case we're not trimming
1091     FGInterface::set_Velocities_Wind_Body(u, v, w);
1092
1093     update_ic();
1094     fgic->SetUBodyFpsIC(u);
1095     fgic->SetVBodyFpsIC(v);
1096     fgic->SetWBodyFpsIC(w);
1097     needTrim=true;
1098 }
1099
1100 //Euler angles
1101 void FGJSBsim::set_Euler_Angles( double phi, double theta, double psi )
1102 {
1103     SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Euler_Angles: "
1104        << phi << ", " << theta << ", " << psi );
1105
1106     // In case we're not trimming
1107     FGInterface::set_Euler_Angles(phi, theta, psi);
1108
1109     update_ic();
1110     fgic->SetThetaRadIC(theta);
1111     fgic->SetPhiRadIC(phi);
1112     fgic->SetPsiRadIC(psi);
1113     needTrim=true;
1114 }
1115
1116 //Flight Path
1117 void FGJSBsim::set_Climb_Rate( double roc)
1118 {
1119     SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Climb_Rate: " << roc );
1120
1121     // In case we're not trimming
1122     FGInterface::set_Climb_Rate(roc);
1123
1124     update_ic();
1125     //since both climb rate and flight path angle are set in the FG
1126     //startup sequence, something is needed to keep one from cancelling
1127     //out the other.
1128     if( !(fabs(roc) > 1 && fabs(fgic->GetFlightPathAngleRadIC()) < 0.01) ) {
1129       fgic->SetClimbRateFpsIC(roc);
1130     }
1131     needTrim=true;
1132 }
1133
1134 void FGJSBsim::set_Gamma_vert_rad( double gamma)
1135 {
1136     SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Gamma_vert_rad: " << gamma );
1137
1138     update_ic();
1139     if( !(fabs(gamma) < 0.01 && fabs(fgic->GetClimbRateFpsIC()) > 1) ) {
1140       fgic->SetFlightPathAngleRadIC(gamma);
1141     }
1142     needTrim=true;
1143 }
1144
1145 void FGJSBsim::init_gear(void )
1146 {
1147     FGGroundReactions* gr=fdmex->GetGroundReactions();
1148     int Ngear=GroundReactions->GetNumGearUnits();
1149     for (int i=0;i<Ngear;i++) {
1150       FGLGear *gear = gr->GetGearUnit(i);
1151       SGPropertyNode * node = fgGetNode("gear/gear", i, true);
1152       node->setDoubleValue("xoffset-in", gear->GetBodyLocation()(1));
1153       node->setDoubleValue("yoffset-in", gear->GetBodyLocation()(2));
1154       node->setDoubleValue("zoffset-in", gear->GetBodyLocation()(3));
1155       node->setBoolValue("wow", gear->GetWOW());
1156       node->setDoubleValue("rollspeed-ms", gear->GetWheelRollVel()*0.3043);
1157       node->setBoolValue("has-brake", gear->GetBrakeGroup() > 0);
1158       node->setDoubleValue("position-norm", gear->GetGearUnitPos());
1159       node->setDoubleValue("tire-pressure-norm", gear->GetTirePressure());
1160       node->setDoubleValue("compression-norm", gear->GetCompLen());
1161       node->setDoubleValue("compression-ft", gear->GetCompLen());
1162       if ( gear->GetSteerable() )
1163         node->setDoubleValue("steering-norm", gear->GetSteerNorm());
1164     }
1165 }
1166
1167 void FGJSBsim::update_gear(void)
1168 {
1169     FGGroundReactions* gr=fdmex->GetGroundReactions();
1170     int Ngear=GroundReactions->GetNumGearUnits();
1171     for (int i=0;i<Ngear;i++) {
1172       FGLGear *gear = gr->GetGearUnit(i);
1173       SGPropertyNode * node = fgGetNode("gear/gear", i, true);
1174       node->getChild("wow", 0, true)->setBoolValue( gear->GetWOW());
1175       node->getChild("rollspeed-ms", 0, true)->setDoubleValue(gear->GetWheelRollVel()*0.3043);
1176       node->getChild("position-norm", 0, true)->setDoubleValue(gear->GetGearUnitPos());
1177       gear->SetTirePressure(node->getDoubleValue("tire-pressure-norm"));
1178       node->setDoubleValue("compression-norm", gear->GetCompLen());
1179       node->setDoubleValue("compression-ft", gear->GetCompLen());
1180       if ( gear->GetSteerable() )
1181         node->setDoubleValue("steering-norm", gear->GetSteerNorm());
1182     }
1183 }
1184
1185 void FGJSBsim::do_trim(void)
1186 {
1187   FGTrim *fgtrim;
1188
1189   if ( fgGetBool("/sim/presets/onground") )
1190   {
1191     fgtrim = new FGTrim(fdmex,tGround);
1192   } else {
1193     fgtrim = new FGTrim(fdmex,tLongitudinal);
1194   }
1195
1196   if ( !fgtrim->DoTrim() ) {
1197     fgtrim->Report();
1198     fgtrim->TrimStats();
1199   } else {
1200     trimmed->setBoolValue(true);
1201   }
1202   delete fgtrim;
1203
1204   pitch_trim->setDoubleValue( FCS->GetPitchTrimCmd() );
1205   throttle_trim->setDoubleValue( FCS->GetThrottleCmd(0) );
1206   aileron_trim->setDoubleValue( FCS->GetDaCmd() );
1207   rudder_trim->setDoubleValue( FCS->GetDrCmd() );
1208
1209   globals->get_controls()->set_elevator_trim(FCS->GetPitchTrimCmd());
1210   globals->get_controls()->set_elevator(FCS->GetDeCmd());
1211   globals->get_controls()->set_throttle(FGControls::ALL_ENGINES,
1212   FCS->GetThrottleCmd(0));
1213
1214   globals->get_controls()->set_aileron(FCS->GetDaCmd());
1215   globals->get_controls()->set_rudder( FCS->GetDrCmd());
1216
1217   SG_LOG( SG_FLIGHT, SG_INFO, "  Trim complete" );
1218 }
1219
1220 void FGJSBsim::update_ic(void)
1221 {
1222    if ( !needTrim ) {
1223      fgic->SetLatitudeRadIC(get_Lat_geocentric() );
1224      fgic->SetLongitudeRadIC( get_Longitude() );
1225      fgic->SetAltitudeASLFtIC( get_Altitude() );
1226      fgic->SetVcalibratedKtsIC( get_V_calibrated_kts() );
1227      fgic->SetThetaRadIC( get_Theta() );
1228      fgic->SetPhiRadIC( get_Phi() );
1229      fgic->SetPsiRadIC( get_Psi() );
1230      fgic->SetClimbRateFpsIC( get_Climb_Rate() );
1231    }
1232 }
1233
1234 bool
1235 FGJSBsim::get_agl_ft(double t, const double pt[3], double alt_off,
1236                      double contact[3], double normal[3], double vel[3],
1237                      double angularVel[3], double *agl)
1238 {
1239    const SGMaterial* material;
1240    simgear::BVHNode::Id id;
1241    if (!FGInterface::get_agl_ft(t, pt, alt_off, contact, normal, vel,
1242                                 angularVel, material, id))
1243        return false;
1244    SGGeod geodPt = SGGeod::fromCart(SG_FEET_TO_METER*SGVec3d(pt));
1245    SGQuatd hlToEc = SGQuatd::fromLonLat(geodPt);
1246    *agl = dot(hlToEc.rotate(SGVec3d(0, 0, 1)), SGVec3d(contact) - SGVec3d(pt));
1247    return true;
1248 }
1249
1250 inline static double dot3(const FGColumnVector3& a, const FGColumnVector3& b)
1251 {
1252     return a(1) * b(1) + a(2) * b(2) + a(3) * b(3);
1253 }
1254
1255 inline static double sqr(double x)
1256 {
1257     return x * x;
1258 }
1259
1260 static double angle_diff(double a, double b)
1261 {
1262     double diff = fabs(a - b);
1263     if (diff > 180) diff = 360 - diff;
1264
1265     return diff;
1266 }
1267
1268 static void check_hook_solution(const FGColumnVector3& ground_normal_body, double E, double hook_length, double sin_fi_guess, double cos_fi_guess, double* sin_fis, double* cos_fis, double* fis, int* points)
1269 {
1270     FGColumnVector3 tip(-hook_length * cos_fi_guess, 0, hook_length * sin_fi_guess);
1271     double dist = dot3(tip, ground_normal_body);
1272     if (fabs(dist + E) < 0.0001) {
1273         sin_fis[*points] = sin_fi_guess;
1274         cos_fis[*points] = cos_fi_guess;
1275         fis[*points] = atan2(sin_fi_guess, cos_fi_guess) * SG_RADIANS_TO_DEGREES;
1276         (*points)++;
1277     }
1278 }
1279
1280
1281 static void check_hook_solution(const FGColumnVector3& ground_normal_body, double E, double hook_length, double sin_fi_guess, double* sin_fis, double* cos_fis, double* fis, int* points)
1282 {
1283     if (sin_fi_guess >= -1 && sin_fi_guess <= 1) {
1284         double cos_fi_guess = sqrt(1 - sqr(sin_fi_guess));
1285         check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess, cos_fi_guess, sin_fis, cos_fis, fis, points);
1286         if (fabs(cos_fi_guess) > SG_EPSILON) {
1287             check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess, -cos_fi_guess, sin_fis, cos_fis, fis, points);
1288         }
1289     }
1290 }
1291
1292 void FGJSBsim::update_external_forces(double t_off)
1293 {
1294     const FGMatrix33& Tb2l = Propagate->GetTb2l();
1295     const FGMatrix33& Tl2b = Propagate->GetTl2b();
1296     const FGLocation& Location = Propagate->GetLocation();
1297     const FGMatrix33& Tec2l = Location.GetTec2l();
1298
1299     double hook_area[4][3];
1300
1301     FGColumnVector3 hook_root_body = MassBalance->StructuralToBody(hook_root_struct);
1302     FGColumnVector3 hook_root = Location.LocalToLocation(Tb2l *   hook_root_body);
1303     hook_area[1][0] = hook_root(1);
1304     hook_area[1][1] = hook_root(2);
1305     hook_area[1][2] = hook_root(3);
1306
1307     hook_length = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-length-ft", 6.75);
1308     double fi_min = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-min-deg", -18);
1309     double fi_max = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-max-deg", 30);
1310     double fi = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-norm") * (fi_max - fi_min) + fi_min;
1311     double cos_fi = cos(fi * SG_DEGREES_TO_RADIANS);
1312     double sin_fi = sin(fi * SG_DEGREES_TO_RADIANS);
1313
1314     FGColumnVector3 hook_tip_body = hook_root_body;
1315     hook_tip_body(1) -= hook_length * cos_fi;
1316     hook_tip_body(3) += hook_length * sin_fi;
1317
1318     double contact[3];
1319     double ground_normal[3];
1320     double ground_vel[3];
1321     double ground_angular_vel[3];
1322     double root_agl_ft;
1323
1324     if (!got_wire) {
1325         bool got = get_agl_ft(t_off, hook_area[1], 0, contact, ground_normal,
1326                               ground_vel, ground_angular_vel, &root_agl_ft);
1327         if (got && root_agl_ft > 0 && root_agl_ft < hook_length) {
1328             FGColumnVector3 ground_normal_body = Tl2b * (Tec2l * FGColumnVector3(ground_normal[0], ground_normal[1], ground_normal[2]));
1329             FGColumnVector3 contact_body = Tl2b * Location.LocationToLocal(FGColumnVector3(contact[0], contact[1], contact[2]));
1330             double D = -dot3(contact_body, ground_normal_body);
1331
1332             // check hook tip agl against same ground plane
1333             double hook_tip_agl_ft = dot3(hook_tip_body, ground_normal_body) + D;
1334             if (hook_tip_agl_ft < 0) {
1335
1336                 // hook tip: hx - l cos, hy, hz + l sin
1337                 // on ground:  - n0 l cos + n2 l sin + E = 0
1338
1339                 double E = D + dot3(hook_root_body, ground_normal_body);
1340
1341                 // substitue x = sin fi, cos fi = sqrt(1 - x * x)
1342                 // and rearrange to get a quadratic with coeffs:
1343                 double a = sqr(hook_length) * (sqr(ground_normal_body(1)) + sqr(ground_normal_body(3)));
1344                 double b = 2 * E * ground_normal_body(3) * hook_length;
1345                 double c = sqr(E) - sqr(ground_normal_body(1) * hook_length);
1346
1347                 double disc = sqr(b) - 4 * a * c;
1348                 if (disc >= 0) {
1349                     double delta = sqrt(disc) / (2 * a);
1350
1351                     // allow 4 solutions for safety, should never happen
1352                     double sin_fis[4];
1353                     double cos_fis[4];
1354                     double fis[4];
1355                     int points = 0;
1356
1357                     double sin_fi_guess = -b / (2 * a) - delta;
1358                     check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess, sin_fis, cos_fis, fis, &points);
1359                     check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess + 2 * delta, sin_fis, cos_fis, fis, &points);
1360
1361                     if (points == 2) {
1362                         double diff1 = angle_diff(fi, fis[0]);
1363                         double diff2 = angle_diff(fi, fis[1]);
1364                         int point = diff1 < diff2 ? 0 : 1;
1365                         fi = fis[point];
1366                         sin_fi = sin_fis[point];
1367                         cos_fi = cos_fis[point];
1368                         hook_tip_body(1) = hook_root_body(1) - hook_length * cos_fi;
1369                         hook_tip_body(3) = hook_root_body(3) + hook_length * sin_fi;
1370                     }
1371                 }
1372             }
1373         }
1374     } else {
1375         FGColumnVector3 hook_root_vel = Propagate->GetVel() + (Tb2l * (Propagate->GetPQR() *  hook_root_body));
1376         double wire_ends_ec[2][3];
1377         double wire_vel_ec[2][3];
1378         get_wire_ends_ft(t_off, wire_ends_ec, wire_vel_ec);
1379         FGColumnVector3 wire_vel_1 = Tec2l * FGColumnVector3(wire_vel_ec[0][0], wire_vel_ec[0][1], wire_vel_ec[0][2]);
1380         FGColumnVector3 wire_vel_2 = Tec2l * FGColumnVector3(wire_vel_ec[1][0], wire_vel_ec[1][1], wire_vel_ec[1][2]);
1381         FGColumnVector3 rel_vel = hook_root_vel - (wire_vel_1 + wire_vel_2) / 2;
1382         if (rel_vel.Magnitude() < 3) {
1383             got_wire = false;
1384             release_wire();
1385             fgSetDouble("/fdm/jsbsim/external_reactions/hook/magnitude", 0.0);
1386         } else {
1387             FGColumnVector3 wire_end1_body = Tl2b * Location.LocationToLocal(FGColumnVector3(wire_ends_ec[0][0], wire_ends_ec[0][1], wire_ends_ec[0][2])) - hook_root_body;
1388             FGColumnVector3 wire_end2_body = Tl2b * Location.LocationToLocal(FGColumnVector3(wire_ends_ec[1][0], wire_ends_ec[1][1], wire_ends_ec[1][2])) - hook_root_body;
1389             FGColumnVector3 force_plane_normal = wire_end1_body * wire_end2_body;
1390             force_plane_normal.Normalize();
1391             cos_fi = dot3(force_plane_normal, FGColumnVector3(0, 0, 1));
1392             if (cos_fi < 0) cos_fi = -cos_fi;
1393             sin_fi = sqrt(1 - sqr(cos_fi));
1394             fi = atan2(sin_fi, cos_fi) * SG_RADIANS_TO_DEGREES;
1395
1396             fgSetDouble("/fdm/jsbsim/external_reactions/hook/x", -cos_fi);
1397             fgSetDouble("/fdm/jsbsim/external_reactions/hook/y", 0);
1398             fgSetDouble("/fdm/jsbsim/external_reactions/hook/z", sin_fi);
1399             fgSetDouble("/fdm/jsbsim/external_reactions/hook/magnitude", fgGetDouble("/fdm/jsbsim/systems/hook/force"));
1400         }
1401     }
1402
1403     FGColumnVector3 hook_tip = Location.LocalToLocation(Tb2l * hook_tip_body);
1404
1405     hook_area[0][0] = hook_tip(1);
1406     hook_area[0][1] = hook_tip(2);
1407     hook_area[0][2] = hook_tip(3);
1408
1409     if (!got_wire) {
1410         // The previous positions.
1411         hook_area[2][0] = last_hook_root[0];
1412         hook_area[2][1] = last_hook_root[1];
1413         hook_area[2][2] = last_hook_root[2];
1414         hook_area[3][0] = last_hook_tip[0];
1415         hook_area[3][1] = last_hook_tip[1];
1416         hook_area[3][2] = last_hook_tip[2];
1417
1418         // Check if we caught a wire.
1419         // Returns true if we caught one.
1420         if (caught_wire_ft(t_off, hook_area)) {
1421                 got_wire = true;
1422         }
1423     }
1424
1425     // save actual position as old position ...
1426     last_hook_tip[0] = hook_area[0][0];
1427     last_hook_tip[1] = hook_area[0][1];
1428     last_hook_tip[2] = hook_area[0][2];
1429     last_hook_root[0] = hook_area[1][0];
1430     last_hook_root[1] = hook_area[1][1];
1431     last_hook_root[2] = hook_area[1][2];
1432
1433     fgSetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-deg", fi);
1434 }
1435