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 #include <simgear/sg_inlines.h>
  30
  31 #include <stdio.h>    //    size_t
  32 #include <string>
  33
  34 #include <simgear/constants.h>
  35 #include <simgear/debug/logstream.hxx>
  36 #include <simgear/math/sg_geodesy.hxx>
  37 #include <simgear/misc/sg_path.hxx>
  38 #include <simgear/structure/commands.hxx>
  39
  40 #include <FDM/flight.hxx>
  41
  42 #include <Aircraft/controls.hxx>
  43 #include <Main/globals.hxx>
  44 #include <Main/fg_props.hxx>
  45
  46 #include "JSBSim.hxx"
  47 #include <FDM/JSBSim/FGFDMExec.h>
  48 #include <FDM/JSBSim/FGJSBBase.h>
  49 #include <FDM/JSBSim/initialization/FGInitialCondition.h>
  50 #include <FDM/JSBSim/initialization/FGTrim.h>
  51 #include <FDM/JSBSim/models/FGModel.h>
  52 #include <FDM/JSBSim/models/FGAircraft.h>
  53 #include <FDM/JSBSim/models/FGFCS.h>
  54 #include <FDM/JSBSim/models/FGPropagate.h>
  55 #include <FDM/JSBSim/models/FGAuxiliary.h>
  56 #include <FDM/JSBSim/models/FGInertial.h>
  57 #include <FDM/JSBSim/models/FGAtmosphere.h>
  58 #include <FDM/JSBSim/models/FGMassBalance.h>
  59 #include <FDM/JSBSim/models/FGAerodynamics.h>
  60 #include <FDM/JSBSim/models/FGLGear.h>
  61 #include <FDM/JSBSim/models/FGGroundReactions.h>
  62 #include <FDM/JSBSim/models/FGPropulsion.h>
  63 #include <FDM/JSBSim/models/FGAccelerations.h>
  64 #include <FDM/JSBSim/models/atmosphere/FGWinds.h>
  65 #include <FDM/JSBSim/models/propulsion/FGEngine.h>
  66 #include <FDM/JSBSim/models/propulsion/FGPiston.h>
  67 #include <FDM/JSBSim/models/propulsion/FGTurbine.h>
  68 #include <FDM/JSBSim/models/propulsion/FGTurboProp.h>
  69 #include <FDM/JSBSim/models/propulsion/FGRocket.h>
  70 #include <FDM/JSBSim/models/propulsion/FGElectric.h>
  71 #include <FDM/JSBSim/models/propulsion/FGNozzle.h>
  72 #include <FDM/JSBSim/models/propulsion/FGPropeller.h>
  73 #include <FDM/JSBSim/models/propulsion/FGRotor.h>
  74 #include <FDM/JSBSim/models/propulsion/FGTank.h>
  75 #include <FDM/JSBSim/input_output/FGPropertyManager.h>
  76 #include <FDM/JSBSim/input_output/FGGroundCallback.h>
  77
  78 using namespace JSBSim;
  79
  80 static inline double
  81 FMAX (double a, double b)
  82 {
  83   return a > b ? a : b;
  84 }
  85
  86 class FGFSGroundCallback : public FGGroundCallback {
  87 public:
  88   FGFSGroundCallback(FGJSBsim* ifc) : mInterface(ifc) {}
  89   virtual ~FGFSGroundCallback() {}
  90
  91   /** Get the altitude above sea level dependent on the location. */
  92   virtual double GetAltitude(const FGLocation& l) const {
  93     double pt[3] = { SG_FEET_TO_METER*l(eX),
  94                      SG_FEET_TO_METER*l(eY),
  95                      SG_FEET_TO_METER*l(eZ) };
  96     double lat, lon, alt;
  97     sgCartToGeod( pt, &lat, &lon, &alt);
  98     return alt * SG_METER_TO_FEET;
  99   }
 100
 101   /** Compute the altitude above ground. */
 102   virtual double GetAGLevel(double t, const FGLocation& l,
 103                             FGLocation& cont, FGColumnVector3& n,
 104                             FGColumnVector3& v, FGColumnVector3& w) const {
 105     double loc_cart[3] = { l(eX), l(eY), l(eZ) };
 106     double contact[3], normal[3], vel[3], angularVel[3], agl = 0;
 107     mInterface->get_agl_ft(t, loc_cart, SG_METER_TO_FEET*2, contact, normal,
 108                            vel, angularVel, &agl);
 109     n = FGColumnVector3( normal[0], normal[1], normal[2] );
 110     v = FGColumnVector3( vel[0], vel[1], vel[2] );
 111     w = FGColumnVector3( angularVel[0], angularVel[1], angularVel[2] );
 112     cont = FGColumnVector3( contact[0], contact[1], contact[2] );
 113     return agl;
 114   }
 115 private:
 116   FGJSBsim* mInterface;
 117 };
 118
 119 // FG uses a squared normalized magnitude for turbulence
 120 // this lookup table maps fg's severity levels
 121 // none(0), light(1/3), moderate(2/3) and severe(3/3)
 122 // to the POE table indexes 0, 3, 4 and 7
 123 class FGTurbulenceSeverityTable : public FGTable {
 124 public:
 125   FGTurbulenceSeverityTable() : FGTable(4) {
 126     *this << (0.0/9.0) << 0.0;
 127     *this << (1.0/9.0) << 3.0;
 128     *this << (4.0/9.0) << 4.0;
 129     *this << (9.0/9.0) << 7.0;
 130   }
 131 };
 132
 133 /******************************************************************************/
 134 std::map<std::string,int> FGJSBsim::TURBULENCE_TYPE_NAMES;
 135
 136 static FGTurbulenceSeverityTable TurbulenceSeverityTable;
 137
 138 FGJSBsim::FGJSBsim( double dt )
 139   : FGInterface(dt), got_wire(false)
 140 {
 141     bool result;
 142     if( TURBULENCE_TYPE_NAMES.empty() ) {
 143         TURBULENCE_TYPE_NAMES["ttNone"]     = FGWinds::ttNone;
 144         TURBULENCE_TYPE_NAMES["ttStandard"] = FGWinds::ttStandard;
 145         TURBULENCE_TYPE_NAMES["ttCulp"]     = FGWinds::ttCulp;
 146         TURBULENCE_TYPE_NAMES["ttMilspec"]  = FGWinds::ttMilspec;
 147         TURBULENCE_TYPE_NAMES["ttTustin"]   = FGWinds::ttTustin;
 148     }
 149
 150                                 // Set up the debugging level
 151                                 // FIXME: this will not respond to
 152                                 // runtime changes
 153
 154                                 // if flight is excluded, don't bother
 155     if ((logbuf::get_log_classes() & SG_FLIGHT) != 0) {
 156
 157                                 // do a rough-and-ready mapping to
 158                                 // the levels documented in FGFDMExec.h
 159         switch (logbuf::get_log_priority()) {
 160         case SG_BULK:
 161             FGJSBBase::debug_lvl = 0x1f;
 162             break;
 163         case SG_DEBUG:
 164             FGJSBBase::debug_lvl = 0x0f;
 165         case SG_INFO:
 166             FGJSBBase::debug_lvl = 0x01;
 167             break;
 168         case SG_WARN:
 169         case SG_ALERT:
 170             FGJSBBase::debug_lvl = 0x00;
 171             break;
 172         }
 173     }
 174
 175     fdmex = new FGFDMExec( (FGPropertyManager*)globals->get_props() );
 176
 177     // Register ground callback.
 178     fdmex->SetGroundCallback( new FGFSGroundCallback(this) );
 179
 180     Atmosphere      = fdmex->GetAtmosphere();
 181     Winds           = fdmex->GetWinds();
 182     FCS             = fdmex->GetFCS();
 183     MassBalance     = fdmex->GetMassBalance();
 184     Propulsion      = fdmex->GetPropulsion();
 185     Aircraft        = fdmex->GetAircraft();
 186     Propagate       = fdmex->GetPropagate();
 187     Auxiliary       = fdmex->GetAuxiliary();
 188     Inertial        = fdmex->GetInertial();
 189     Aerodynamics    = fdmex->GetAerodynamics();
 190     GroundReactions = fdmex->GetGroundReactions();
 191     Accelerations   = fdmex->GetAccelerations();
 192
 193     fgic=fdmex->GetIC();
 194     needTrim=true;
 195
 196     SGPath aircraft_path( fgGetString("/sim/aircraft-dir") );
 197
 198     SGPath engine_path( fgGetString("/sim/aircraft-dir") );
 199     engine_path.append( "Engine" );
 200
 201     SGPath systems_path( fgGetString("/sim/aircraft-dir") );
 202     systems_path.append( "Systems" );
 203
 204 // deprecate sim-time-sec for simulation/sim-time-sec
 205 // remove alias with increased configuration file version number (2.1 or later)
 206     SGPropertyNode * node = fgGetNode("/fdm/jsbsim/simulation/sim-time-sec");
 207     fgGetNode("/fdm/jsbsim/sim-time-sec", true)->alias( node );
 208 // end of sim-time-sec deprecation patch
 209
 210     fdmex->Setdt( dt );
 211
 212     result = fdmex->LoadModel( aircraft_path.str(),
 213                                engine_path.str(),
 214                                systems_path.str(),
 215                                fgGetString("/sim/aero"), false );
 216
 217     if (result) {
 218       SG_LOG( SG_FLIGHT, SG_INFO, "  loaded aero.");
 219     } else {
 220       SG_LOG( SG_FLIGHT, SG_INFO,
 221               "  aero does not exist (you may have mis-typed the name).");
 222       throw(-1);
 223     }
 224
 225     SG_LOG( SG_FLIGHT, SG_INFO, "" );
 226     SG_LOG( SG_FLIGHT, SG_INFO, "" );
 227     SG_LOG( SG_FLIGHT, SG_INFO, "After loading aero definition file ..." );
 228
 229     int Neng = Propulsion->GetNumEngines();
 230     SG_LOG( SG_FLIGHT, SG_INFO, "num engines = " << Neng );
 231
 232     if ( GroundReactions->GetNumGearUnits() <= 0 ) {
 233         SG_LOG( SG_FLIGHT, SG_ALERT, "num gear units = "
 234                 << GroundReactions->GetNumGearUnits() );
 235         SG_LOG( SG_FLIGHT, SG_ALERT, "This is a very bad thing because with 0 gear units, the ground trimming");
 236         SG_LOG( SG_FLIGHT, SG_ALERT, "routine (coming up later in the code) will core dump.");
 237         SG_LOG( SG_FLIGHT, SG_ALERT, "Halting the sim now, and hoping a solution will present itself soon!");
 238         exit(-1);
 239     }
 240
 241     init_gear();
 242
 243     // Set initial fuel levels if provided.
 244     for (unsigned int i = 0; i < Propulsion->GetNumTanks(); i++) {
 245       double d;
 246       SGPropertyNode * node = fgGetNode("/consumables/fuel/tank", i, true);
 247       FGTank* tank = Propulsion->GetTank(i);
 248
 249       d = node->getNode( "density-ppg", true )->getDoubleValue();
 250       if( d > 0.0 ) {
 251         tank->SetDensity( d );
 252       } else {
 253         node->getNode( "density-ppg", true )->setDoubleValue( SG_MAX2<double>(tank->GetDensity(), 0.1) );
 254       }
 255
 256       d = node->getNode( "level-lbs", true )->getDoubleValue();
 257       if( d > 0.0 ) {
 258         tank->SetContents( d );
 259       } else {
 260         node->getNode( "level-lbs", true )->setDoubleValue( tank->GetContents() );
 261       }
 262       /* Capacity is read-only in FGTank and can't be overwritten from FlightGear */
 263       node->getNode("capacity-gal_us", true )->setDoubleValue( tank->GetCapacityGallons() );
 264     }
 265     Propulsion->SetFuelFreeze((fgGetNode("/sim/freeze/fuel",true))->getBoolValue());
 266
 267     fgSetDouble("/fdm/trim/pitch-trim", FCS->GetPitchTrimCmd());
 268     fgSetDouble("/fdm/trim/throttle",   FCS->GetThrottleCmd(0));
 269     fgSetDouble("/fdm/trim/aileron",    FCS->GetDaCmd());
 270     fgSetDouble("/fdm/trim/rudder",     FCS->GetDrCmd());
 271
 272     startup_trim = fgGetNode("/sim/presets/trim", true);
 273
 274     trimmed = fgGetNode("/fdm/trim/trimmed", true);
 275     trimmed->setBoolValue(false);
 276
 277     pitch_trim = fgGetNode("/fdm/trim/pitch-trim", true );
 278     throttle_trim = fgGetNode("/fdm/trim/throttle", true );
 279     aileron_trim = fgGetNode("/fdm/trim/aileron", true );
 280     rudder_trim = fgGetNode("/fdm/trim/rudder", true );
 281
 282     stall_warning = fgGetNode("/sim/alarms/stall-warning",true);
 283     stall_warning->setDoubleValue(0);
 284
 285
 286     flap_pos_pct=fgGetNode("/surface-positions/flap-pos-norm",true);
 287     elevator_pos_pct=fgGetNode("/surface-positions/elevator-pos-norm",true);
 288     left_aileron_pos_pct
 289         =fgGetNode("/surface-positions/left-aileron-pos-norm",true);
 290     right_aileron_pos_pct
 291         =fgGetNode("/surface-positions/right-aileron-pos-norm",true);
 292     rudder_pos_pct=fgGetNode("/surface-positions/rudder-pos-norm",true);
 293     speedbrake_pos_pct
 294         =fgGetNode("/surface-positions/speedbrake-pos-norm",true);
 295     spoilers_pos_pct=fgGetNode("/surface-positions/spoilers-pos-norm",true);
 296     tailhook_pos_pct=fgGetNode("/gear/tailhook/position-norm",true);
 297     wing_fold_pos_pct=fgGetNode("surface-positions/wing-fold-pos-norm",true);
 298
 299     elevator_pos_pct->setDoubleValue(0);
 300     left_aileron_pos_pct->setDoubleValue(0);
 301     right_aileron_pos_pct->setDoubleValue(0);
 302     rudder_pos_pct->setDoubleValue(0);
 303     flap_pos_pct->setDoubleValue(0);
 304     speedbrake_pos_pct->setDoubleValue(0);
 305     spoilers_pos_pct->setDoubleValue(0);
 306
 307     ab_brake_engaged = fgGetNode("/autopilot/autobrake/engaged", true);
 308     ab_brake_left_pct = fgGetNode("/autopilot/autobrake/brake-left-output", true);
 309     ab_brake_right_pct = fgGetNode("/autopilot/autobrake/brake-right-output", true);
 310
 311     temperature = fgGetNode("/environment/temperature-degc",true);
 312     pressure = fgGetNode("/environment/pressure-inhg",true);
 313     pressureSL = fgGetNode("/environment/pressure-sea-level-inhg",true);
 314     density = fgGetNode("/environment/density-slugft3",true);
 315     ground_wind = fgGetNode("/environment/config/boundary/entry[0]/wind-speed-kt",true);
 316     turbulence_gain = fgGetNode("/environment/turbulence/magnitude-norm",true);
 317     turbulence_rate = fgGetNode("/environment/turbulence/rate-hz",true);
 318     turbulence_model = fgGetNode("/environment/params/jsbsim-turbulence-model",true);
 319
 320     wind_from_north= fgGetNode("/environment/wind-from-north-fps",true);
 321     wind_from_east = fgGetNode("/environment/wind-from-east-fps" ,true);
 322     wind_from_down = fgGetNode("/environment/wind-from-down-fps" ,true);
 323
 324     slaved = fgGetNode("/sim/slaved/enabled", true);
 325
 326     for (unsigned int i = 0; i < Propulsion->GetNumEngines(); i++) {
 327       SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 328       Propulsion->GetEngine(i)->GetThruster()->SetRPM(node->getDoubleValue("rpm") /
 329                      Propulsion->GetEngine(i)->GetThruster()->GetGearRatio());
 330     }
 331
 332     hook_root_struct = FGColumnVector3(
 333         fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-offset-x-in", 196),
 334         fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-offset-y-in", 0),
 335         fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-offset-z-in", -16));
 336     last_hook_tip[0] = 0; last_hook_tip[1] = 0; last_hook_tip[2] = 0;
 337     last_hook_root[0] = 0; last_hook_root[1] = 0; last_hook_root[2] = 0;
 338
 339     crashed = false;
 340 }
 341
 342 /******************************************************************************/
 343 FGJSBsim::~FGJSBsim(void)
 344 {
 345   delete fdmex;
 346 }
 347
 348 /******************************************************************************/
 349
 350 // Initialize the JSBsim flight model, dt is the time increment for
 351 // each subsequent iteration through the EOM
 352
 353 void FGJSBsim::init()
 354 {
 355     SG_LOG( SG_FLIGHT, SG_INFO, "Starting and initializing JSBsim" );
 356
 357     // Explicitly call the superclass's
 358     // init method first.
 359
 360     if (fgGetBool("/environment/params/control-fdm-atmosphere")) {
 361       Atmosphere->SetTemperature(temperature->getDoubleValue(), get_Altitude(), FGAtmosphere::eCelsius);
 362       Atmosphere->SetPressureSL(pressureSL->getDoubleValue(), FGAtmosphere::eInchesHg);
 363       // initialize to no turbulence, these values get set in the update loop
 364       Winds->SetTurbType(FGWinds::ttNone);
 365       Winds->SetTurbGain(0.0);
 366       Winds->SetTurbRate(0.0);
 367       Winds->SetWindspeed20ft(0.0);
 368       Winds->SetProbabilityOfExceedence(0.0);
 369     }
 370
 371     fgic->SetSeaLevelRadiusFtIC( get_Sea_level_radius() );
 372     fgic->SetWindNEDFpsIC( -wind_from_north->getDoubleValue(),
 373                            -wind_from_east->getDoubleValue(),
 374                            -wind_from_down->getDoubleValue() );
 375
 376     //Atmosphere->SetExTemperature(get_Static_temperature());
 377     //Atmosphere->SetExPressure(get_Static_pressure());
 378     //Atmosphere->SetExDensity(get_Density());
 379     SG_LOG(SG_FLIGHT,SG_INFO,"T,p,rho: " << fdmex->GetAtmosphere()->GetTemperature()
 380      << ", " << fdmex->GetAtmosphere()->GetPressure()
 381      << ", " << fdmex->GetAtmosphere()->GetDensity() );
 382
 383 // deprecate egt_degf for egt-degf to have consistent naming
 384 // TODO: remove this for 2.6.0
 385     for (unsigned int i=0; i < Propulsion->GetNumEngines(); i++) {
 386       SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 387       SGPropertyNode * egtn = node->getNode( "egt_degf" );
 388       if( egtn != NULL ) {
 389         SG_LOG(SG_FLIGHT,SG_ALERT,
 390                "*** Aircraft uses deprecated and now unsupported node egt_degf. Please upgrade to egt-degf");
 391       }
 392     }
 393 // end of egt_degf deprecation patch
 394
 395     FCS->SetDfPos( ofNorm, globals->get_controls()->get_flaps() );
 396
 397     common_init();
 398
 399     copy_to_JSBsim();
 400     fdmex->RunIC();     //loop JSBSim once w/o integrating
 401     if (fgGetBool("/sim/presets/running")) {
 402       Propulsion->InitRunning(-1);
 403       for (unsigned int i = 0; i < Propulsion->GetNumEngines(); i++) {
 404         FGPiston* eng = (FGPiston*)Propulsion->GetEngine(i);
 405         globals->get_controls()->set_magnetos(i, eng->GetMagnetos());
 406         globals->get_controls()->set_mixture(i, FCS->GetMixtureCmd(i));
 407       }
 408     }
 409
 410     if ( startup_trim->getBoolValue() ) {
 411       FGLocation cart(fgic->GetLongitudeRadIC(), fgic->GetLatitudeRadIC(),
 412                       get_Sea_level_radius() + fgic->GetAltitudeASLFtIC());
 413       double cart_pos[3], contact[3], d[3], vel[3], agl;
 414       update_ground_cache(cart, cart_pos, 0.01);
 415
 416       get_agl_ft(fdmex->GetSimTime(), cart_pos, SG_METER_TO_FEET*2, contact,
 417                  d, vel, d, &agl);
 418       double terrain_alt = sqrt(contact[0]*contact[0] + contact[1]*contact[1]
 419            + contact[2]*contact[2]) - get_Sea_level_radius();
 420
 421       SG_LOG(SG_FLIGHT, SG_INFO, "Ready to trim, terrain elevation is: "
 422                                  << terrain_alt * SG_METER_TO_FEET );
 423
 424       if (fgGetBool("/sim/presets/onground")) {
 425         FGColumnVector3 gndVelNED = cart.GetTec2l()
 426                                   * FGColumnVector3(vel[0], vel[1], vel[2]);
 427         fgic->SetVNorthFpsIC(gndVelNED(1));
 428         fgic->SetVEastFpsIC(gndVelNED(2));
 429         fgic->SetVDownFpsIC(gndVelNED(3));
 430       }
 431       fgic->SetTerrainElevationFtIC( terrain_alt );
 432       do_trim();
 433       needTrim = false;
 434     }
 435
 436     copy_from_JSBsim(); //update the bus
 437
 438     SG_LOG( SG_FLIGHT, SG_INFO, "  Initialized JSBSim with:" );
 439
 440     switch(fgic->GetSpeedSet()) {
 441     case setned:
 442         SG_LOG(SG_FLIGHT,SG_INFO, "  Vn,Ve,Vd= "
 443                << Propagate->GetVel(FGJSBBase::eNorth) << ", "
 444                << Propagate->GetVel(FGJSBBase::eEast) << ", "
 445                << Propagate->GetVel(FGJSBBase::eDown) << " ft/s");
 446     break;
 447     case setuvw:
 448         SG_LOG(SG_FLIGHT,SG_INFO, "  U,V,W= "
 449                << Propagate->GetUVW(1) << ", "
 450                << Propagate->GetUVW(2) << ", "
 451                << Propagate->GetUVW(3) << " ft/s");
 452     break;
 453     case setmach:
 454         SG_LOG(SG_FLIGHT,SG_INFO, "  Mach: "
 455                << Auxiliary->GetMach() );
 456     break;
 457     case setvc:
 458     default:
 459         SG_LOG(SG_FLIGHT,SG_INFO, "  Indicated Airspeed: "
 460                << Auxiliary->GetVcalibratedKTS() << " knots" );
 461     break;
 462     }
 463
 464     stall_warning->setDoubleValue(0);
 465
 466     SG_LOG( SG_FLIGHT, SG_INFO, "  Bank Angle: "
 467             << Propagate->GetEuler(FGJSBBase::ePhi)*RADTODEG << " deg" );
 468     SG_LOG( SG_FLIGHT, SG_INFO, "  Pitch Angle: "
 469             << Propagate->GetEuler(FGJSBBase::eTht)*RADTODEG << " deg" );
 470     SG_LOG( SG_FLIGHT, SG_INFO, "  True Heading: "
 471             << Propagate->GetEuler(FGJSBBase::ePsi)*RADTODEG << " deg" );
 472     SG_LOG( SG_FLIGHT, SG_INFO, "  Latitude: "
 473             << Propagate->GetLocation().GetLatitudeDeg() << " deg" );
 474     SG_LOG( SG_FLIGHT, SG_INFO, "  Longitude: "
 475             << Propagate->GetLocation().GetLongitudeDeg() << " deg" );
 476     SG_LOG( SG_FLIGHT, SG_INFO, "  Altitude: "
 477             << Propagate->GetAltitudeASL() << " feet" );
 478     SG_LOG( SG_FLIGHT, SG_INFO, "  loaded initial conditions" );
 479
 480     SG_LOG( SG_FLIGHT, SG_INFO, "  set dt" );
 481
 482     SG_LOG( SG_FLIGHT, SG_INFO, "Finished initializing JSBSim" );
 483
 484     SG_LOG( SG_FLIGHT, SG_INFO, "FGControls::get_gear_down()= " <<
 485                                   globals->get_controls()->get_gear_down() );
 486 }
 487
 488 /******************************************************************************/
 489
 490 void FGJSBsim::unbind()
 491 {
 492   fdmex->Unbind();
 493   FGInterface::unbind();
 494 }
 495
 496 /******************************************************************************/
 497
 498 // Run an iteration of the EOM (equations of motion)
 499
 500 void FGJSBsim::update( double dt )
 501 {
 502     if(crashed) {
 503       if(!fgGetBool("/sim/crashed"))
 504         fgSetBool("/sim/crashed", true);
 505       return;
 506     }
 507
 508     if (is_suspended())
 509       return;
 510
 511     int multiloop = _calc_multiloop(dt);
 512     FGLocation cart = Auxiliary->GetLocationVRP();
 513     double cart_pos[3];
 514
 515     update_ground_cache(cart, cart_pos, dt);
 516
 517     copy_to_JSBsim();
 518
 519     trimmed->setBoolValue(false);
 520
 521     for ( int i=0; i < multiloop; i++ ) {
 522       fdmex->Run();
 523       update_external_forces(fdmex->GetSimTime() + i * fdmex->GetDeltaT());
 524     }
 525
 526     FGJSBBase::Message* msg;
 527     while ((msg = fdmex->ProcessNextMessage()) != NULL) {
 528 //      msg = fdmex->ProcessNextMessage();
 529       switch (msg->type) {
 530       case FGJSBBase::Message::eText:
 531         if (msg->text == "Crash Detected: Simulation FREEZE.")
 532           crashed = true;
 533         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text );
 534         break;
 535       case FGJSBBase::Message::eBool:
 536         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text << " " << msg->bVal );
 537         break;
 538       case FGJSBBase::Message::eInteger:
 539         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text << " " << msg->iVal );
 540         break;
 541       case FGJSBBase::Message::eDouble:
 542         SG_LOG( SG_FLIGHT, SG_INFO, msg->messageId << ": " << msg->text << " " << msg->dVal );
 543         break;
 544       default:
 545         SG_LOG( SG_FLIGHT, SG_INFO, "Unrecognized message type." );
 546         break;
 547       }
 548     }
 549
 550     // translate JSBsim back to FG structure so that the
 551     // autopilot (and the rest of the sim can use the updated values
 552     copy_from_JSBsim();
 553 }
 554
 555 /******************************************************************************/
 556
 557 void FGJSBsim::suspend()
 558 {
 559   fdmex->Hold();
 560   SGSubsystem::suspend();
 561 }
 562
 563 /******************************************************************************/
 564
 565 void FGJSBsim::resume()
 566 {
 567   fdmex->Resume();
 568   SGSubsystem::resume();
 569 }
 570
 571 /******************************************************************************/
 572
 573 // Convert from the FGInterface struct to the JSBsim generic_ struct
 574
 575 bool FGJSBsim::copy_to_JSBsim()
 576 {
 577     unsigned int i;
 578
 579     // copy control positions into the JSBsim structure
 580
 581     FCS->SetDaCmd( globals->get_controls()->get_aileron());
 582     FCS->SetRollTrimCmd( globals->get_controls()->get_aileron_trim() );
 583     FCS->SetDeCmd( globals->get_controls()->get_elevator());
 584     FCS->SetPitchTrimCmd( globals->get_controls()->get_elevator_trim() );
 585     FCS->SetDrCmd( -globals->get_controls()->get_rudder() );
 586     FCS->SetYawTrimCmd( -globals->get_controls()->get_rudder_trim() );
 587     FCS->SetDsCmd( globals->get_controls()->get_rudder() );
 588     FCS->SetDfCmd( globals->get_controls()->get_flaps() );
 589     FCS->SetDsbCmd( globals->get_controls()->get_speedbrake() );
 590     FCS->SetDspCmd( globals->get_controls()->get_spoilers() );
 591
 592         // Parking brake sets minimum braking
 593         // level for mains.
 594     double parking_brake = globals->get_controls()->get_brake_parking();
 595     double left_brake = globals->get_controls()->get_brake_left();
 596     double right_brake = globals->get_controls()->get_brake_right();
 597
 598     if (ab_brake_engaged->getBoolValue()) {
 599       left_brake = ab_brake_left_pct->getDoubleValue();
 600       right_brake = ab_brake_right_pct->getDoubleValue();
 601     }
 602
 603     FCS->SetLBrake(FMAX(left_brake, parking_brake));
 604     FCS->SetRBrake(FMAX(right_brake, parking_brake));
 605
 606
 607     FCS->SetCBrake( 0.0 );
 608     // FCS->SetCBrake( globals->get_controls()->get_brake(2) );
 609
 610     FCS->SetGearCmd( globals->get_controls()->get_gear_down());
 611     for (i = 0; i < Propulsion->GetNumEngines(); i++) {
 612       SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 613
 614       FCS->SetThrottleCmd(i, globals->get_controls()->get_throttle(i));
 615       FCS->SetMixtureCmd(i, globals->get_controls()->get_mixture(i));
 616       FCS->SetPropAdvanceCmd(i, globals->get_controls()->get_prop_advance(i));
 617       FCS->SetFeatherCmd(i, globals->get_controls()->get_feather(i));
 618
 619       switch (Propulsion->GetEngine(i)->GetType()) {
 620       case FGEngine::etPiston:
 621         { // FGPiston code block
 622         FGPiston* eng = (FGPiston*)Propulsion->GetEngine(i);
 623         eng->SetMagnetos( globals->get_controls()->get_magnetos(i) );
 624         break;
 625         } // end FGPiston code block
 626       case FGEngine::etTurbine:
 627         { // FGTurbine code block
 628         FGTurbine* eng = (FGTurbine*)Propulsion->GetEngine(i);
 629         eng->SetAugmentation( globals->get_controls()->get_augmentation(i) );
 630         eng->SetReverse( globals->get_controls()->get_reverser(i) );
 631         //eng->SetInjection( globals->get_controls()->get_water_injection(i) );
 632         eng->SetCutoff( globals->get_controls()->get_cutoff(i) );
 633         eng->SetIgnition( globals->get_controls()->get_ignition(i) );
 634         break;
 635         } // end FGTurbine code block
 636       case FGEngine::etRocket:
 637         { // FGRocket code block
 638 //        FGRocket* eng = (FGRocket*)Propulsion->GetEngine(i);
 639         break;
 640         } // end FGRocket code block
 641       case FGEngine::etTurboprop:
 642         { // FGTurboProp code block
 643         FGTurboProp* eng = (FGTurboProp*)Propulsion->GetEngine(i);
 644         eng->SetReverse( globals->get_controls()->get_reverser(i) );
 645         eng->SetCutoff( globals->get_controls()->get_cutoff(i) );
 646         eng->SetIgnition( globals->get_controls()->get_ignition(i) );
 647
 648         eng->SetGeneratorPower( globals->get_controls()->get_generator_breaker(i) );
 649         eng->SetCondition( globals->get_controls()->get_condition(i) );
 650         break;
 651         } // end FGTurboProp code block
 652       default:
 653         break;
 654       }
 655
 656       { // FGEngine code block
 657       FGEngine* eng = Propulsion->GetEngine(i);
 658
 659       eng->SetStarter( globals->get_controls()->get_starter(i) );
 660       eng->SetRunning( node->getBoolValue("running") );
 661       } // end FGEngine code block
 662     }
 663
 664
 665     Propagate->SetSeaLevelRadius( get_Sea_level_radius() );
 666
 667     Atmosphere->SetTemperature(temperature->getDoubleValue(), get_Altitude(), FGAtmosphere::eCelsius);
 668     Atmosphere->SetPressureSL(pressureSL->getDoubleValue(), FGAtmosphere::eInchesHg);
 669
 670     Winds->SetTurbType((FGWinds::tType)TURBULENCE_TYPE_NAMES[turbulence_model->getStringValue()]);
 671     switch( Winds->GetTurbType() ) {
 672         case FGWinds::ttStandard:
 673         case FGWinds::ttCulp: {
 674             double tmp = turbulence_gain->getDoubleValue();
 675             Winds->SetTurbGain(tmp * tmp * 100.0);
 676             Winds->SetTurbRate(turbulence_rate->getDoubleValue());
 677             break;
 678         }
 679         case FGWinds::ttMilspec:
 680         case FGWinds::ttTustin: {
 681             // milspec turbulence: 3=light, 4=moderate, 6=severe turbulence
 682             // turbulence_gain normalized: 0: none, 1/3: light, 2/3: moderate, 3/3: severe
 683             double tmp = turbulence_gain->getDoubleValue();
 684             Winds->SetProbabilityOfExceedence(
 685               SGMiscd::roundToInt(TurbulenceSeverityTable.GetValue( tmp ) )
 686             );
 687             Winds->SetWindspeed20ft(ground_wind->getDoubleValue());
 688             break;
 689         }
 690
 691         default:
 692             break;
 693     }
 694
 695     Winds->SetWindNED( -wind_from_north->getDoubleValue(),
 696                        -wind_from_east->getDoubleValue(),
 697                        -wind_from_down->getDoubleValue() );
 698 //    SG_LOG(SG_FLIGHT,SG_INFO, "Wind NED: "
 699 //                  << get_V_north_airmass() << ", "
 700 //                  << get_V_east_airmass()  << ", "
 701 //                  << get_V_down_airmass() );
 702
 703     for (i = 0; i < Propulsion->GetNumTanks(); i++) {
 704       SGPropertyNode * node = fgGetNode("/consumables/fuel/tank", i, true);
 705       FGTank * tank = Propulsion->GetTank(i);
 706       double fuelDensity = node->getDoubleValue("density-ppg");
 707
 708       if (fuelDensity < 0.1)
 709         fuelDensity = 6.0; // Use average fuel value
 710
 711       tank->SetDensity(fuelDensity);
 712       tank->SetContents(node->getDoubleValue("level-lbs"));
 713     }
 714
 715     Propulsion->SetFuelFreeze((fgGetNode("/sim/freeze/fuel",true))->getBoolValue());
 716     fdmex->SetChild(slaved->getBoolValue());
 717
 718     return true;
 719 }
 720
 721 /******************************************************************************/
 722
 723 // Convert from the JSBsim generic_ struct to the FGInterface struct
 724
 725 bool FGJSBsim::copy_from_JSBsim()
 726 {
 727     unsigned int i, j;
 728 /*
 729     _set_Inertias( MassBalance->GetMass(),
 730                    MassBalance->GetIxx(),
 731                    MassBalance->GetIyy(),
 732                    MassBalance->GetIzz(),
 733                    MassBalance->GetIxz() );
 734 */
 735     _set_CG_Position( MassBalance->GetXYZcg(1),
 736                       MassBalance->GetXYZcg(2),
 737                       MassBalance->GetXYZcg(3) );
 738
 739     _set_Accels_Body( Accelerations->GetBodyAccel(1),
 740                       Accelerations->GetBodyAccel(2),
 741                       Accelerations->GetBodyAccel(3) );
 742
 743     _set_Accels_CG_Body_N ( Auxiliary->GetNcg(1),
 744                             Auxiliary->GetNcg(2),
 745                             Auxiliary->GetNcg(3) );
 746
 747     _set_Accels_Pilot_Body( Auxiliary->GetPilotAccel(1),
 748                             Auxiliary->GetPilotAccel(2),
 749                             Auxiliary->GetPilotAccel(3) );
 750
 751     _set_Nlf( Auxiliary->GetNlf() );
 752
 753     // Velocities
 754
 755     _set_Velocities_Local( Propagate->GetVel(FGJSBBase::eNorth),
 756                            Propagate->GetVel(FGJSBBase::eEast),
 757                            Propagate->GetVel(FGJSBBase::eDown) );
 758
 759     _set_Velocities_Wind_Body( Propagate->GetUVW(1),
 760                                Propagate->GetUVW(2),
 761                                Propagate->GetUVW(3) );
 762
 763     // Make the HUD work ...
 764     _set_Velocities_Ground( Propagate->GetVel(FGJSBBase::eNorth),
 765                             Propagate->GetVel(FGJSBBase::eEast),
 766                             -Propagate->GetVel(FGJSBBase::eDown) );
 767
 768     _set_V_rel_wind( Auxiliary->GetVt() );
 769
 770     _set_V_equiv_kts( Auxiliary->GetVequivalentKTS() );
 771
 772     _set_V_calibrated_kts( Auxiliary->GetVcalibratedKTS() );
 773
 774     _set_V_ground_speed( Auxiliary->GetVground() );
 775
 776     _set_Omega_Body( Propagate->GetPQR(FGJSBBase::eP),
 777                      Propagate->GetPQR(FGJSBBase::eQ),
 778                      Propagate->GetPQR(FGJSBBase::eR) );
 779
 780     _set_Euler_Rates( Auxiliary->GetEulerRates(FGJSBBase::ePhi),
 781                       Auxiliary->GetEulerRates(FGJSBBase::eTht),
 782                       Auxiliary->GetEulerRates(FGJSBBase::ePsi) );
 783
 784     _set_Mach_number( Auxiliary->GetMach() );
 785
 786     // Positions of Visual Reference Point
 787     FGLocation l = Auxiliary->GetLocationVRP();
 788     _updateGeocentricPosition( l.GetLatitude(), l.GetLongitude(),
 789                                l.GetRadius() - get_Sea_level_radius() );
 790
 791     _set_Altitude_AGL( Propagate->GetDistanceAGL() );
 792     {
 793       double loc_cart[3] = { l(FGJSBBase::eX), l(FGJSBBase::eY), l(FGJSBBase::eZ) };
 794       double contact[3], d[3], sd, t;
 795       is_valid_m(&t, d, &sd);
 796       get_agl_ft(t, loc_cart, SG_METER_TO_FEET*2, contact, d, d, d, &sd);
 797       double rwrad
 798         = FGColumnVector3( contact[0], contact[1], contact[2] ).Magnitude();
 799       _set_Runway_altitude( rwrad - get_Sea_level_radius() );
 800     }
 801
 802     _set_Euler_Angles( Propagate->GetEuler(FGJSBBase::ePhi),
 803                        Propagate->GetEuler(FGJSBBase::eTht),
 804                        Propagate->GetEuler(FGJSBBase::ePsi) );
 805
 806     _set_Alpha( Auxiliary->Getalpha() );
 807     _set_Beta( Auxiliary->Getbeta() );
 808
 809
 810     _set_Gamma_vert_rad( Auxiliary->GetGamma() );
 811
 812     _set_Earth_position_angle( Propagate->GetEarthPositionAngle() );
 813
 814     _set_Climb_Rate( Propagate->Gethdot() );
 815
 816     const FGMatrix33& Tl2b = Propagate->GetTl2b();
 817     for ( i = 1; i <= 3; i++ ) {
 818         for ( j = 1; j <= 3; j++ ) {
 819             _set_T_Local_to_Body( i, j, Tl2b(i,j) );
 820         }
 821     }
 822
 823     // Copy the engine values from JSBSim.
 824     for ( i=0; i < Propulsion->GetNumEngines(); i++ ) {
 825       SGPropertyNode * node = fgGetNode("engines/engine", i, true);
 826       SGPropertyNode * tnode = node->getChild("thruster", 0, true);
 827       FGThruster * thruster = Propulsion->GetEngine(i)->GetThruster();
 828
 829       switch (Propulsion->GetEngine(i)->GetType()) {
 830       case FGEngine::etPiston:
 831         { // FGPiston code block
 832         FGPiston* eng = (FGPiston*)Propulsion->GetEngine(i);
 833         node->setDoubleValue("egt-degf", eng->getExhaustGasTemp_degF());
 834         node->setDoubleValue("oil-temperature-degf", eng->getOilTemp_degF());
 835         node->setDoubleValue("oil-pressure-psi", eng->getOilPressure_psi());
 836         node->setDoubleValue("mp-osi", eng->getManifoldPressure_inHg());
 837         // NOTE: mp-osi is not in ounces per square inch.
 838         // This error is left for reasons of backwards compatibility with
 839         // existing FlightGear sound and instrument configurations.
 840         node->setDoubleValue("mp-inhg", eng->getManifoldPressure_inHg());
 841         node->setDoubleValue("cht-degf", eng->getCylinderHeadTemp_degF());
 842         node->setDoubleValue("rpm", eng->getRPM());
 843         } // end FGPiston code block
 844         break;
 845       case FGEngine::etRocket:
 846         { // FGRocket code block
 847 //        FGRocket* eng = (FGRocket*)Propulsion->GetEngine(i);
 848         } // end FGRocket code block
 849         break;
 850       case FGEngine::etTurbine:
 851         { // FGTurbine code block
 852         FGTurbine* eng = (FGTurbine*)Propulsion->GetEngine(i);
 853         node->setDoubleValue("n1", eng->GetN1());
 854         node->setDoubleValue("n2", eng->GetN2());
 855         node->setDoubleValue("egt-degf", 32 + eng->GetEGT()*9/5);
 856         node->setBoolValue("augmentation", eng->GetAugmentation());
 857         node->setBoolValue("water-injection", eng->GetInjection());
 858         node->setBoolValue("ignition", eng->GetIgnition() != 0);
 859         node->setDoubleValue("nozzle-pos-norm", eng->GetNozzle());
 860         node->setDoubleValue("inlet-pos-norm", eng->GetInlet());
 861         node->setDoubleValue("oil-pressure-psi", eng->getOilPressure_psi());
 862         node->setBoolValue("reversed", eng->GetReversed());
 863         node->setBoolValue("cutoff", eng->GetCutoff());
 864         node->setDoubleValue("epr", eng->GetEPR());
 865         globals->get_controls()->set_reverser(i, eng->GetReversed() );
 866         globals->get_controls()->set_cutoff(i, eng->GetCutoff() );
 867         globals->get_controls()->set_water_injection(i, eng->GetInjection() );
 868         globals->get_controls()->set_augmentation(i, eng->GetAugmentation() );
 869         } // end FGTurbine code block
 870         break;
 871       case FGEngine::etTurboprop:
 872         { // FGTurboProp code block
 873         FGTurboProp* eng = (FGTurboProp*)Propulsion->GetEngine(i);
 874         node->setDoubleValue("n1", eng->GetN1());
 875         //node->setDoubleValue("n2", eng->GetN2());
 876         node->setDoubleValue("itt_degf", 32 + eng->GetITT()*9/5);
 877         node->setBoolValue("ignition", eng->GetIgnition() != 0);
 878         node->setDoubleValue("nozzle-pos-norm", eng->GetNozzle());
 879         node->setDoubleValue("inlet-pos-norm", eng->GetInlet());
 880         node->setDoubleValue("oil-pressure-psi", eng->getOilPressure_psi());
 881         node->setBoolValue("reversed", eng->GetReversed());
 882         node->setBoolValue("cutoff", eng->GetCutoff());
 883         node->setBoolValue("starting", eng->GetEngStarting());
 884         node->setBoolValue("generator-power", eng->GetGeneratorPower());
 885         node->setBoolValue("damaged", eng->GetCondition() != 0);
 886         node->setBoolValue("ielu-intervent", eng->GetIeluIntervent());
 887         node->setDoubleValue("oil-temperature-degf", eng->getOilTemp_degF());
 888 //        node->setBoolValue("onfire", eng->GetFire());
 889         globals->get_controls()->set_reverser(i, eng->GetReversed() );
 890         globals->get_controls()->set_cutoff(i, eng->GetCutoff() );
 891         } // end FGTurboProp code block
 892         break;
 893       case FGEngine::etElectric:
 894         { // FGElectric code block
 895         FGElectric* eng = (FGElectric*)Propulsion->GetEngine(i);
 896         node->setDoubleValue("rpm", eng->getRPM());
 897         } // end FGElectric code block
 898         break;
 899       case FGEngine::etUnknown:
 900         break;
 901       }
 902
 903       { // FGEngine code block
 904       FGEngine* eng = Propulsion->GetEngine(i);
 905       node->setDoubleValue("fuel-flow-gph", eng->getFuelFlow_gph());
 906       node->setDoubleValue("thrust_lb", thruster->GetThrust());
 907       node->setDoubleValue("fuel-flow_pph", eng->getFuelFlow_pph());
 908       node->setBoolValue("running", eng->GetRunning());
 909       node->setBoolValue("starter", eng->GetStarter());
 910       node->setBoolValue("cranking", eng->GetCranking());
 911       globals->get_controls()->set_starter(i, eng->GetStarter() );
 912       } // end FGEngine code block
 913
 914       switch (thruster->GetType()) {
 915       case FGThruster::ttNozzle:
 916         { // FGNozzle code block
 917 //        FGNozzle* noz = (FGNozzle*)thruster;
 918         } // end FGNozzle code block
 919         break;
 920       case FGThruster::ttPropeller:
 921         { // FGPropeller code block
 922         FGPropeller* prop = (FGPropeller*)thruster;
 923         tnode->setDoubleValue("rpm", thruster->GetRPM());
 924         tnode->setDoubleValue("pitch", prop->GetPitch());
 925         tnode->setDoubleValue("torque", prop->GetTorque());
 926         tnode->setBoolValue("feathered", prop->GetFeather());
 927         } // end FGPropeller code block
 928         break;
 929       case FGThruster::ttRotor:
 930         { // FGRotor code block
 931 //        FGRotor* rotor = (FGRotor*)thruster;
 932         } // end FGRotor code block
 933         break;
 934       case FGThruster::ttDirect:
 935         { // Direct code block
 936         } // end Direct code block
 937         break;
 938       }
 939
 940     }
 941
 942     // Copy the fuel levels from JSBSim if fuel
 943     // freeze not enabled.
 944     if ( ! Propulsion->GetFuelFreeze() ) {
 945       for (i = 0; i < Propulsion->GetNumTanks(); i++) {
 946         SGPropertyNode * node = fgGetNode("/consumables/fuel/tank", i, true);
 947         FGTank* tank = Propulsion->GetTank(i);
 948         double contents = tank->GetContents();
 949         double temp = tank->GetTemperature_degC();
 950         double fuelDensity = tank->GetDensity();
 951
 952         if (fuelDensity < 0.1)
 953           fuelDensity = 6.0; // Use average fuel value
 954
 955         node->setDoubleValue("density-ppg" , fuelDensity);
 956         node->setDoubleValue("level-lbs", contents);
 957         if (temp != -9999.0) node->setDoubleValue("temperature_degC", temp);
 958       }
 959     }
 960
 961     update_gear();
 962
 963     stall_warning->setDoubleValue( Aerodynamics->GetStallWarn() );
 964
 965     elevator_pos_pct->setDoubleValue( FCS->GetDePos(ofNorm) );
 966     left_aileron_pos_pct->setDoubleValue( FCS->GetDaLPos(ofNorm) );
 967     right_aileron_pos_pct->setDoubleValue( FCS->GetDaRPos(ofNorm) );
 968     rudder_pos_pct->setDoubleValue( -1*FCS->GetDrPos(ofNorm) );
 969     flap_pos_pct->setDoubleValue( FCS->GetDfPos(ofNorm) );
 970     speedbrake_pos_pct->setDoubleValue( FCS->GetDsbPos(ofNorm) );
 971     spoilers_pos_pct->setDoubleValue( FCS->GetDspPos(ofNorm) );
 972     tailhook_pos_pct->setDoubleValue( FCS->GetTailhookPos() );
 973     wing_fold_pos_pct->setDoubleValue( FCS->GetWingFoldPos() );
 974
 975     // force a sim crashed if crashed (altitude AGL < 0)
 976     if (get_Altitude_AGL() < -100.0) {
 977          fdmex->SuspendIntegration();
 978          crashed = true;
 979     }
 980
 981     return true;
 982 }
 983
 984
 985 bool FGJSBsim::ToggleDataLogging(void)
 986 {
 987   // ToDo: handle this properly
 988   fdmex->DisableOutput();
 989   return false;
 990 }
 991
 992
 993 bool FGJSBsim::ToggleDataLogging(bool state)
 994 {
 995     if (state) {
 996       fdmex->EnableOutput();
 997       return true;
 998     } else {
 999       fdmex->DisableOutput();
1000       return false;
1001     }
1002 }
1003
1004
1005 //Positions
1006 void FGJSBsim::set_Latitude(double lat)
1007 {
1008   static SGConstPropertyNode_ptr altitude = fgGetNode("/position/altitude-ft");
1009   double alt;
1010   double sea_level_radius_meters, lat_geoc;
1011
1012   if ( altitude->getDoubleValue() > -9990 )
1013     alt = altitude->getDoubleValue();
1014   else
1015     alt = 0.0;
1016
1017   SG_LOG(SG_FLIGHT,SG_INFO,"FGJSBsim::set_Latitude: " << lat );
1018   SG_LOG(SG_FLIGHT,SG_INFO," cur alt (ft) =  " << alt );
1019
1020   sgGeodToGeoc( lat, alt * SG_FEET_TO_METER,
1021                     &sea_level_radius_meters, &lat_geoc );
1022   _set_Sea_level_radius( sea_level_radius_meters * SG_METER_TO_FEET  );
1023
1024   if (needTrim) {
1025     fgic->SetSeaLevelRadiusFtIC( sea_level_radius_meters * SG_METER_TO_FEET  );
1026     fgic->SetLatitudeRadIC( lat_geoc );
1027   }
1028   else {
1029     Propagate->SetLatitude(lat_geoc);
1030     FGInterface::set_Latitude(lat);
1031   }
1032 }
1033
1034
1035 void FGJSBsim::set_Longitude(double lon)
1036 {
1037   SG_LOG(SG_FLIGHT,SG_INFO,"FGJSBsim::set_Longitude: " << lon );
1038
1039   if (needTrim)
1040     fgic->SetLongitudeRadIC(lon);
1041   else {
1042     Propagate->SetLongitude(lon);
1043     FGInterface::set_Longitude(lon);
1044   }
1045 }
1046
1047 // Sets the altitude above sea level.
1048 void FGJSBsim::set_Altitude(double alt)
1049 {
1050   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Altitude: " << alt );
1051
1052   if (needTrim)
1053     fgic->SetAltitudeASLFtIC(alt);
1054   else {
1055     Propagate->SetAltitudeASL(alt);
1056     FGInterface::set_Altitude(alt);
1057   }
1058 }
1059
1060 void FGJSBsim::set_V_calibrated_kts(double vc)
1061 {
1062     SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_V_calibrated_kts: " <<  vc );
1063
1064   if (needTrim)
1065     fgic->SetVcalibratedKtsIC(vc);
1066   else {
1067     double mach = getMachFromVcas(vc);
1068     double temp = 1.8*(temperature->getDoubleValue()+273.15);
1069     double soundSpeed = sqrt(1.4*1716.0*temp);
1070     FGColumnVector3 vUVW = Propagate->GetUVW();
1071     vUVW.Normalize();
1072     vUVW *= mach * soundSpeed;
1073     Propagate->SetUVW(1, vUVW(1));
1074     Propagate->SetUVW(2, vUVW(2));
1075     Propagate->SetUVW(3, vUVW(3));
1076
1077     FGInterface::set_V_calibrated_kts(vc);
1078   }
1079 }
1080
1081 void FGJSBsim::set_Mach_number(double mach)
1082 {
1083   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Mach_number: " <<  mach );
1084
1085   if (needTrim)
1086     fgic->SetMachIC(mach);
1087   else {
1088     double temp = 1.8*(temperature->getDoubleValue()+273.15);
1089     double soundSpeed = sqrt(1.4*1716.0*temp);
1090     FGColumnVector3 vUVW = Propagate->GetUVW();
1091     vUVW.Normalize();
1092     vUVW *= mach * soundSpeed;
1093     Propagate->SetUVW(1, vUVW(1));
1094     Propagate->SetUVW(2, vUVW(2));
1095     Propagate->SetUVW(3, vUVW(3));
1096
1097     FGInterface::set_Mach_number(mach);
1098   }
1099 }
1100
1101 void FGJSBsim::set_Velocities_Local( double north, double east, double down )
1102 {
1103   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Velocities_Local: "
1104      << north << ", " <<  east << ", " << down );
1105
1106   if (needTrim) {
1107     fgic->SetVNorthFpsIC(north);
1108     fgic->SetVEastFpsIC(east);
1109     fgic->SetVDownFpsIC(down);
1110   }
1111   else {
1112     FGColumnVector3 vNED(north, east, down);
1113     FGColumnVector3 vUVW = Propagate->GetTl2b() * vNED;
1114     Propagate->SetUVW(1, vUVW(1));
1115     Propagate->SetUVW(2, vUVW(2));
1116     Propagate->SetUVW(3, vUVW(3));
1117
1118     FGInterface::set_Velocities_Local(north, east, down);
1119   }
1120 }
1121
1122 void FGJSBsim::set_Velocities_Wind_Body( double u, double v, double w)
1123 {
1124   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Velocities_Wind_Body: "
1125      << u << ", " <<  v << ", " <<  w );
1126
1127   if (needTrim) {
1128     fgic->SetUBodyFpsIC(u);
1129     fgic->SetVBodyFpsIC(v);
1130     fgic->SetWBodyFpsIC(w);
1131   }
1132   else {
1133     Propagate->SetUVW(1, u);
1134     Propagate->SetUVW(2, v);
1135     Propagate->SetUVW(3, w);
1136
1137     FGInterface::set_Velocities_Wind_Body(u, v, w);
1138   }
1139 }
1140
1141 //Euler angles
1142 void FGJSBsim::set_Euler_Angles( double phi, double theta, double psi )
1143 {
1144   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Euler_Angles: "
1145      << phi << ", " << theta << ", " << psi );
1146
1147   if (needTrim) {
1148     fgic->SetThetaRadIC(theta);
1149     fgic->SetPhiRadIC(phi);
1150     fgic->SetPsiRadIC(psi);
1151   }
1152   else {
1153     FGQuaternion quat(phi, theta, psi);
1154     FGMatrix33 Tl2b = quat.GetT();
1155     FGMatrix33 Ti2b = Tl2b*Propagate->GetTi2l();
1156     FGQuaternion Qi = Ti2b.GetQuaternion();
1157     Propagate->SetInertialOrientation(Qi);
1158
1159     FGInterface::set_Euler_Angles(phi, theta, psi);
1160   }
1161 }
1162
1163 //Flight Path
1164 void FGJSBsim::set_Climb_Rate( double roc)
1165 {
1166   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Climb_Rate: " << roc );
1167
1168   //since both climb rate and flight path angle are set in the FG
1169   //startup sequence, something is needed to keep one from cancelling
1170   //out the other.
1171   if( !(fabs(roc) > 1 && fabs(fgic->GetFlightPathAngleRadIC()) < 0.01) ) {
1172     if (needTrim)
1173       fgic->SetClimbRateFpsIC(roc);
1174     else {
1175       FGColumnVector3 vNED = Propagate->GetVel();
1176       vNED(FGJSBBase::eDown) = -roc;
1177       FGColumnVector3 vUVW = Propagate->GetTl2b() * vNED;
1178       Propagate->SetUVW(1, vUVW(1));
1179       Propagate->SetUVW(2, vUVW(2));
1180       Propagate->SetUVW(3, vUVW(3));
1181
1182       FGInterface::set_Climb_Rate(roc);
1183     }
1184   }
1185 }
1186
1187 void FGJSBsim::set_Gamma_vert_rad( double gamma)
1188 {
1189   SG_LOG(SG_FLIGHT,SG_INFO, "FGJSBsim::set_Gamma_vert_rad: " << gamma );
1190
1191   if( !(fabs(gamma) < 0.01 && fabs(fgic->GetClimbRateFpsIC()) > 1) ) {
1192     if (needTrim)
1193       fgic->SetFlightPathAngleRadIC(gamma);
1194     else {
1195       FGColumnVector3 vNED = Propagate->GetVel();
1196       double vt = vNED.Magnitude();
1197       vNED(FGJSBBase::eDown) = -vt * sin(gamma);
1198       FGColumnVector3 vUVW = Propagate->GetTl2b() * vNED;
1199       Propagate->SetUVW(1, vUVW(1));
1200       Propagate->SetUVW(2, vUVW(2));
1201       Propagate->SetUVW(3, vUVW(3));
1202
1203       FGInterface::set_Gamma_vert_rad(gamma);
1204     }
1205   }
1206 }
1207 // Reverse the VCAS formula to obtain the corresponding Mach number. For subsonic
1208 // speeds, the reversed formula has a closed form. For supersonic speeds, the
1209 // formula is reversed by the Newton-Raphson algorithm.
1210
1211 double FGJSBsim::getMachFromVcas(double vcas)
1212 {
1213   double p=pressure->getDoubleValue();
1214   double psl=fdmex->GetAtmosphere()->GetPressureSL();
1215   double rhosl=fdmex->GetAtmosphere()->GetDensitySL();
1216
1217   double pt = p + psl*(pow(1+vcas*vcas*rhosl/(7.0*psl),3.5)-1);
1218
1219   if (pt/p < 1.89293)
1220     return sqrt(5.0*(pow(pt/p, 0.2857143) -1)); // Mach < 1
1221   else {
1222     // Mach >= 1
1223     double mach = sqrt(0.77666*pt/p); // Initial guess is based on a quadratic approximation of the Rayleigh formula
1224     double delta = 1.;
1225     double target = pt/(166.92158*p);
1226     int iter = 0;
1227
1228     // Find the root with Newton-Raphson. Since the differential is never zero,
1229     // the function is monotonic and has only one root with a multiplicity of one.
1230     // Convergence is certain.
1231     while (delta > 1E-5 && iter < 10) {
1232       double m2 = mach*mach; // Mach^2
1233       double m6 = m2*m2*m2;  // Mach^6
1234       delta = mach*m6/pow(7.0*m2-1.0,2.5) - target;
1235       double diff = 7.0*m6*(2.0*m2-1)/pow(7.0*m2-1.0,3.5); // Never zero when Mach >= 1
1236       mach -= delta/diff;
1237       iter++;
1238     }
1239
1240     return mach;
1241   }
1242 }
1243
1244 void FGJSBsim::init_gear(void )
1245 {
1246     FGGroundReactions* gr=fdmex->GetGroundReactions();
1247     int Ngear=GroundReactions->GetNumGearUnits();
1248     for (int i=0;i<Ngear;i++) {
1249       FGLGear *gear = gr->GetGearUnit(i);
1250       SGPropertyNode * node = fgGetNode("gear/gear", i, true);
1251       node->setDoubleValue("xoffset-in", gear->GetBodyLocation()(1));
1252       node->setDoubleValue("yoffset-in", gear->GetBodyLocation()(2));
1253       node->setDoubleValue("zoffset-in", gear->GetBodyLocation()(3));
1254       node->setBoolValue("wow", gear->GetWOW());
1255       node->setDoubleValue("rollspeed-ms", gear->GetWheelRollVel()*0.3043);
1256       node->setBoolValue("has-brake", gear->GetBrakeGroup() > 0);
1257       node->setDoubleValue("position-norm", gear->GetGearUnitPos());
1258       node->setDoubleValue("tire-pressure-norm", gear->GetTirePressure());
1259       node->setDoubleValue("compression-norm", gear->GetCompLen());
1260       node->setDoubleValue("compression-ft", gear->GetCompLen());
1261       if ( gear->GetSteerable() )
1262         node->setDoubleValue("steering-norm", gear->GetSteerNorm());
1263     }
1264 }
1265
1266 void FGJSBsim::update_gear(void)
1267 {
1268     FGGroundReactions* gr=fdmex->GetGroundReactions();
1269     int Ngear=GroundReactions->GetNumGearUnits();
1270     for (int i=0;i<Ngear;i++) {
1271       FGLGear *gear = gr->GetGearUnit(i);
1272       SGPropertyNode * node = fgGetNode("gear/gear", i, true);
1273       node->getChild("wow", 0, true)->setBoolValue( gear->GetWOW());
1274       node->getChild("rollspeed-ms", 0, true)->setDoubleValue(gear->GetWheelRollVel()*0.3043);
1275       node->getChild("position-norm", 0, true)->setDoubleValue(gear->GetGearUnitPos());
1276       gear->SetTirePressure(node->getDoubleValue("tire-pressure-norm"));
1277       node->setDoubleValue("compression-norm", gear->GetCompLen());
1278       node->setDoubleValue("compression-ft", gear->GetCompLen());
1279       if ( gear->GetSteerable() )
1280         node->setDoubleValue("steering-norm", gear->GetSteerNorm());
1281     }
1282 }
1283
1284 void FGJSBsim::do_trim(void)
1285 {
1286   FGTrim *fgtrim;
1287
1288   if ( fgGetBool("/sim/presets/onground") )
1289   {
1290     fgtrim = new FGTrim(fdmex,tGround);
1291   } else {
1292     fgtrim = new FGTrim(fdmex,tFull);
1293   }
1294
1295   if ( !fgtrim->DoTrim() ) {
1296     fgtrim->Report();
1297     fgtrim->TrimStats();
1298   } else {
1299     trimmed->setBoolValue(true);
1300   }
1301   delete fgtrim;
1302
1303   pitch_trim->setDoubleValue( FCS->GetPitchTrimCmd() );
1304   throttle_trim->setDoubleValue( FCS->GetThrottleCmd(0) );
1305   aileron_trim->setDoubleValue( FCS->GetDaCmd() );
1306   rudder_trim->setDoubleValue( -FCS->GetDrCmd() );
1307
1308   globals->get_controls()->set_elevator_trim(FCS->GetPitchTrimCmd());
1309   globals->get_controls()->set_elevator(FCS->GetDeCmd());
1310   for( unsigned i = 0; i < Propulsion->GetNumEngines(); i++ )
1311     globals->get_controls()->set_throttle(i, FCS->GetThrottleCmd(i));
1312
1313   globals->get_controls()->set_aileron(FCS->GetDaCmd());
1314   globals->get_controls()->set_rudder( -FCS->GetDrCmd());
1315
1316   SG_LOG( SG_FLIGHT, SG_INFO, "  Trim complete" );
1317 }
1318
1319 bool FGJSBsim::update_ground_cache(FGLocation cart, double* cart_pos, double dt)
1320 {
1321   // Compute the radius of the aircraft. That is the radius of a ball
1322   // where all gear units are in. At the moment it is at least 10ft ...
1323   double acrad = 10.0;
1324   int n_gears = GroundReactions->GetNumGearUnits();
1325   for (int i=0; i<n_gears; ++i) {
1326     FGColumnVector3 bl = GroundReactions->GetGearUnit(i)->GetBodyLocation();
1327     double r = bl.Magnitude();
1328     if (acrad < r)
1329       acrad = r;
1330   }
1331
1332   // Compute the potential movement of this aircraft and query for the
1333   // ground in this area.
1334   double groundCacheRadius = acrad + 2*dt*Propagate->GetUVW().Magnitude();
1335   cart_pos[0] = cart(1);
1336   cart_pos[1] = cart(2);
1337   cart_pos[2] = cart(3);
1338   double t0 = fdmex->GetSimTime();
1339   bool cache_ok = prepare_ground_cache_ft( t0, t0 + dt, cart_pos,
1340                                            groundCacheRadius );
1341   if (!cache_ok) {
1342     SG_LOG(SG_FLIGHT, SG_WARN,
1343            "FGInterface is being called without scenery below the aircraft!");
1344
1345     SG_LOG(SG_FLIGHT, SG_WARN, "altitude         = "
1346                       << fgic->GetAltitudeASLFtIC());
1347
1348     SG_LOG(SG_FLIGHT, SG_WARN, "sea level radius = "
1349                       << get_Sea_level_radius());
1350
1351     SG_LOG(SG_FLIGHT, SG_WARN, "latitude         = "
1352                       << fgic->GetLatitudeRadIC());
1353
1354     SG_LOG(SG_FLIGHT, SG_WARN, "longitude        = "
1355                       << fgic->GetLongitudeRadIC());
1356   }
1357
1358   return cache_ok;
1359 }
1360
1361 bool
1362 FGJSBsim::get_agl_ft(double t, const double pt[3], double alt_off,
1363                      double contact[3], double normal[3], double vel[3],
1364                      double angularVel[3], double *agl)
1365 {
1366    const SGMaterial* material;
1367    simgear::BVHNode::Id id;
1368    if (!FGInterface::get_agl_ft(t, pt, alt_off, contact, normal, vel,
1369                                 angularVel, material, id))
1370        return false;
1371    SGGeod geodPt = SGGeod::fromCart(SG_FEET_TO_METER*SGVec3d(pt));
1372    SGQuatd hlToEc = SGQuatd::fromLonLat(geodPt);
1373    *agl = dot(hlToEc.rotate(SGVec3d(0, 0, 1)), SGVec3d(contact) - SGVec3d(pt));
1374    return true;
1375 }
1376
1377 inline static double sqr(double x)
1378 {
1379     return x * x;
1380 }
1381
1382 static double angle_diff(double a, double b)
1383 {
1384     double diff = fabs(a - b);
1385     if (diff > 180) diff = 360 - diff;
1386
1387     return diff;
1388 }
1389
1390 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)
1391 {
1392     FGColumnVector3 tip(-hook_length * cos_fi_guess, 0, hook_length * sin_fi_guess);
1393     double dist = DotProduct(tip, ground_normal_body);
1394     if (fabs(dist + E) < 0.0001) {
1395         sin_fis[*points] = sin_fi_guess;
1396         cos_fis[*points] = cos_fi_guess;
1397         fis[*points] = atan2(sin_fi_guess, cos_fi_guess) * SG_RADIANS_TO_DEGREES;
1398         (*points)++;
1399     }
1400 }
1401
1402
1403 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)
1404 {
1405     if (sin_fi_guess >= -1 && sin_fi_guess <= 1) {
1406         double cos_fi_guess = sqrt(1 - sqr(sin_fi_guess));
1407         check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess, cos_fi_guess, sin_fis, cos_fis, fis, points);
1408         if (fabs(cos_fi_guess) > SG_EPSILON) {
1409             check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess, -cos_fi_guess, sin_fis, cos_fis, fis, points);
1410         }
1411     }
1412 }
1413
1414 void FGJSBsim::update_external_forces(double t_off)
1415 {
1416     const FGMatrix33& Tb2l = Propagate->GetTb2l();
1417     const FGMatrix33& Tl2b = Propagate->GetTl2b();
1418     const FGLocation& Location = Propagate->GetLocation();
1419     const FGMatrix33& Tec2l = Location.GetTec2l();
1420
1421     double hook_area[4][3];
1422
1423     FGColumnVector3 hook_root_body = MassBalance->StructuralToBody(hook_root_struct);
1424     FGColumnVector3 hook_root = Location.LocalToLocation(Tb2l *   hook_root_body);
1425     hook_area[1][0] = hook_root(1);
1426     hook_area[1][1] = hook_root(2);
1427     hook_area[1][2] = hook_root(3);
1428
1429     hook_length = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-length-ft", 6.75);
1430     double fi_min = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-min-deg", -18);
1431     double fi_max = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-max-deg", 30);
1432     double fi = fgGetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-norm") * (fi_max - fi_min) + fi_min;
1433     double cos_fi = cos(fi * SG_DEGREES_TO_RADIANS);
1434     double sin_fi = sin(fi * SG_DEGREES_TO_RADIANS);
1435
1436     FGColumnVector3 hook_tip_body = hook_root_body;
1437     hook_tip_body(1) -= hook_length * cos_fi;
1438     hook_tip_body(3) += hook_length * sin_fi;
1439
1440     double contact[3];
1441     double ground_normal[3];
1442     double ground_vel[3];
1443     double ground_angular_vel[3];
1444     double root_agl_ft;
1445
1446     if (!got_wire) {
1447         bool got = get_agl_ft(t_off, hook_area[1], 0, contact, ground_normal,
1448                               ground_vel, ground_angular_vel, &root_agl_ft);
1449         if (got && root_agl_ft > 0 && root_agl_ft < hook_length) {
1450             FGColumnVector3 ground_normal_body = Tl2b * (Tec2l * FGColumnVector3(ground_normal[0], ground_normal[1], ground_normal[2]));
1451             FGColumnVector3 contact_body = Tl2b * Location.LocationToLocal(FGColumnVector3(contact[0], contact[1], contact[2]));
1452             double D = -DotProduct(contact_body, ground_normal_body);
1453
1454             // check hook tip agl against same ground plane
1455             double hook_tip_agl_ft = DotProduct(hook_tip_body, ground_normal_body) + D;
1456             if (hook_tip_agl_ft < 0) {
1457
1458                 // hook tip: hx - l cos, hy, hz + l sin
1459                 // on ground:  - n0 l cos + n2 l sin + E = 0
1460
1461                 double E = D + DotProduct(hook_root_body, ground_normal_body);
1462
1463                 // substitue x = sin fi, cos fi = sqrt(1 - x * x)
1464                 // and rearrange to get a quadratic with coeffs:
1465                 double a = sqr(hook_length) * (sqr(ground_normal_body(1)) + sqr(ground_normal_body(3)));
1466                 double b = 2 * E * ground_normal_body(3) * hook_length;
1467                 double c = sqr(E) - sqr(ground_normal_body(1) * hook_length);
1468
1469                 double disc = sqr(b) - 4 * a * c;
1470                 if (disc >= 0) {
1471                     double delta = sqrt(disc) / (2 * a);
1472
1473                     // allow 4 solutions for safety, should never happen
1474                     double sin_fis[4];
1475                     double cos_fis[4];
1476                     double fis[4];
1477                     int points = 0;
1478
1479                     double sin_fi_guess = -b / (2 * a) - delta;
1480                     check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess, sin_fis, cos_fis, fis, &points);
1481                     check_hook_solution(ground_normal_body, E, hook_length, sin_fi_guess + 2 * delta, sin_fis, cos_fis, fis, &points);
1482
1483                     if (points == 2) {
1484                         double diff1 = angle_diff(fi, fis[0]);
1485                         double diff2 = angle_diff(fi, fis[1]);
1486                         int point = diff1 < diff2 ? 0 : 1;
1487                         fi = fis[point];
1488                         sin_fi = sin_fis[point];
1489                         cos_fi = cos_fis[point];
1490                         hook_tip_body(1) = hook_root_body(1) - hook_length * cos_fi;
1491                         hook_tip_body(3) = hook_root_body(3) + hook_length * sin_fi;
1492                     }
1493                 }
1494             }
1495         }
1496     } else {
1497         FGColumnVector3 hook_root_vel = Propagate->GetVel() + (Tb2l * (Propagate->GetPQR() *  hook_root_body));
1498         double wire_ends_ec[2][3];
1499         double wire_vel_ec[2][3];
1500         get_wire_ends_ft(t_off, wire_ends_ec, wire_vel_ec);
1501         FGColumnVector3 wire_vel_1 = Tec2l * FGColumnVector3(wire_vel_ec[0][0], wire_vel_ec[0][1], wire_vel_ec[0][2]);
1502         FGColumnVector3 wire_vel_2 = Tec2l * FGColumnVector3(wire_vel_ec[1][0], wire_vel_ec[1][1], wire_vel_ec[1][2]);
1503         FGColumnVector3 rel_vel = hook_root_vel - (wire_vel_1 + wire_vel_2) / 2;
1504         if (rel_vel.Magnitude() < 3) {
1505             got_wire = false;
1506             release_wire();
1507             fgSetDouble("/fdm/jsbsim/external_reactions/hook/magnitude", 0.0);
1508         } else {
1509             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;
1510             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;
1511             FGColumnVector3 force_plane_normal = wire_end1_body * wire_end2_body;
1512             force_plane_normal.Normalize();
1513             cos_fi = DotProduct(force_plane_normal, FGColumnVector3(0, 0, 1));
1514             if (cos_fi < 0) cos_fi = -cos_fi;
1515             sin_fi = sqrt(1 - sqr(cos_fi));
1516             fi = atan2(sin_fi, cos_fi) * SG_RADIANS_TO_DEGREES;
1517
1518             fgSetDouble("/fdm/jsbsim/external_reactions/hook/x", -cos_fi);
1519             fgSetDouble("/fdm/jsbsim/external_reactions/hook/y", 0);
1520             fgSetDouble("/fdm/jsbsim/external_reactions/hook/z", sin_fi);
1521             fgSetDouble("/fdm/jsbsim/external_reactions/hook/magnitude", fgGetDouble("/fdm/jsbsim/systems/hook/force"));
1522         }
1523     }
1524
1525     FGColumnVector3 hook_tip = Location.LocalToLocation(Tb2l * hook_tip_body);
1526
1527     hook_area[0][0] = hook_tip(1);
1528     hook_area[0][1] = hook_tip(2);
1529     hook_area[0][2] = hook_tip(3);
1530
1531     if (!got_wire) {
1532         // The previous positions.
1533         hook_area[2][0] = last_hook_root[0];
1534         hook_area[2][1] = last_hook_root[1];
1535         hook_area[2][2] = last_hook_root[2];
1536         hook_area[3][0] = last_hook_tip[0];
1537         hook_area[3][1] = last_hook_tip[1];
1538         hook_area[3][2] = last_hook_tip[2];
1539
1540         // Check if we caught a wire.
1541         // Returns true if we caught one.
1542         if (caught_wire_ft(t_off, hook_area)) {
1543                 got_wire = true;
1544         }
1545     }
1546
1547     // save actual position as old position ...
1548     last_hook_tip[0] = hook_area[0][0];
1549     last_hook_tip[1] = hook_area[0][1];
1550     last_hook_tip[2] = hook_area[0][2];
1551     last_hook_root[0] = hook_area[1][0];
1552     last_hook_root[1] = hook_area[1][1];
1553     last_hook_root[2] = hook_area[1][2];
1554
1555     fgSetDouble("/fdm/jsbsim/systems/hook/tailhook-pos-deg", fi);
1556 }
1557