X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FCockpit%2Fsteam.cxx;h=cd78bf303259ab843f2575299c14f3eb0854a6c0;hb=d13b46b8f1efc36057c98fd396c306cbfd7a3612;hp=6eab60f61b317ad7f099b180679829d77e9d3f12;hpb=1882fb0119f1db6f457cc52f8c55a9e718ff028f;p=flightgear.git diff --git a/src/Cockpit/steam.cxx b/src/Cockpit/steam.cxx index 6eab60f61..cd78bf303 100644 --- a/src/Cockpit/steam.cxx +++ b/src/Cockpit/steam.cxx @@ -23,38 +23,40 @@ # include #endif -#if defined( FG_HAVE_NATIVE_SGI_COMPILERS ) -# include -#else -# include -#endif +#include + +#include STL_IOSTREAM #include -#include +#include +#include #include -#include
-#include
-#include -FG_USING_NAMESPACE(std); +SG_USING_NAMESPACE(std); #include "radiostack.hxx" #include "steam.hxx" +static bool isTied = false; + //////////////////////////////////////////////////////////////////////// // Declare the functions that read the variables //////////////////////////////////////////////////////////////////////// -// Anything that reads the BFI directly is not implemented at all! - - double FGSteam::the_STATIC_inhg = 29.92; -double FGSteam::the_ALT_ft = 0.0; +double FGSteam::the_ALT_ft = 0.0; // Indicated altitude double FGSteam::get_ALT_ft() { _CatchUp(); return the_ALT_ft; } -double FGSteam::get_ASI_kias() { return FGBFI::getAirspeed(); } +double FGSteam::the_ALT_datum_mb = 1013.0; +double FGSteam::get_ALT_datum_mb() { return the_ALT_datum_mb; } + +void FGSteam::set_ALT_datum_mb ( double datum_mb ) { + the_ALT_datum_mb = datum_mb; +} + +double FGSteam::get_ASI_kias() { return fgGetDouble("/velocities/airspeed-kt"); } double FGSteam::the_VSI_case = 29.92; double FGSteam::the_VSI_fps = 0.0; @@ -90,15 +92,46 @@ double FGSteam::get_TC_std () { _CatchUp(); return the_TC_std; } //////////////////////////////////////////////////////////////////////// -int FGSteam::_UpdatesPending = 999; /* Forces filter to reset */ +int FGSteam::_UpdatesPending = 1000000; /* Forces filter to reset */ + // FIXME: no need to use static + // functions any longer. + void FGSteam::update ( int timesteps ) { - _UpdatesPending += timesteps; + if (!isTied) { + isTied = true; + fgTie("/steam/airspeed-kt", FGSteam::get_ASI_kias); + fgSetArchivable("/steam/airspeed-kt"); + fgTie("/steam/altitude-ft", FGSteam::get_ALT_ft); + fgSetArchivable("/steam/altitude-ft"); + fgTie("/steam/altimeter-datum-mb", + FGSteam::get_ALT_datum_mb, FGSteam::set_ALT_datum_mb, + false); /* don't modify the value */ + fgSetArchivable("/steam/altimeter-datum-mb"); + fgTie("/steam/turn-rate", FGSteam::get_TC_std); + fgSetArchivable("/steam/turn-rate"); + fgTie("/steam/slip-skid", FGSteam::get_TC_rad); + fgSetArchivable("/steam/slip-skid"); + fgTie("/steam/vertical-speed-fpm", FGSteam::get_VSI_fps); + fgSetArchivable("/steam/vertical-speed-fpm"); + fgTie("/steam/gyro-compass-deg", FGSteam::get_DG_deg); + fgSetArchivable("/steam/gyro-compass-deg"); + fgTie("/steam/adf-deg", FGSteam::get_HackADF_deg); + fgSetArchivable("/steam/adf-deg"); + fgTie("/steam/gyro-compass-error-deg", + FGSteam::get_DG_err, FGSteam::set_DG_err, + false); /* don't modify the value */ + fgSetArchivable("/steam/gyro-compass-error-deg"); + fgTie("/steam/mag-compass-deg", FGSteam::get_MH_deg); + fgSetArchivable("/steam/mag-compass-deg"); + } + _UpdatesPending += timesteps; } +/* tc should be (elapsed_time_between_updates / desired_smoothing_time) */ void FGSteam::set_lowpass ( double *outthe, double inthe, double tc ) { if ( tc < 0.0 ) @@ -110,7 +143,7 @@ void FGSteam::set_lowpass ( double *outthe, double inthe, double tc ) } } else if ( tc < 0.2 ) - { /* Normal mode of operation */ + { /* Normal mode of operation; fast approximation to exp(-tc) */ (*outthe) = (*outthe) * ( 1.0 - tc ) + inthe * tc; } else @@ -127,6 +160,38 @@ void FGSteam::set_lowpass ( double *outthe, double inthe, double tc ) } +#define INHG_TO_MB 33.86388 /* Inches_of_mercury * INHG_TO_MB == millibars. */ + +// Convert air pressure to altitude by ICAO Standard Atmosphere +double pressInHgToAltFt(double p_inhg) +{ + // Ref. Aviation Formulary, Ed Williams, www.best.com/~williams/avform.htm + const double P_0 = 29.92126; // Std. MSL pressure, inHg. (=1013.25 mb) + const double p_Tr = 0.2233609 * P_0; // Pressure at tropopause, same units. + const double h_Tr = 36089.24; // Alt of tropopause, ft. (=11.0 km) + + if (p_inhg > p_Tr) // 0.0 to 11.0 km + return (1.0 - pow((p_inhg / P_0), 1.0 / 5.2558797)) / 6.8755856e-6; + return h_Tr + log10(p_inhg / p_Tr) / -4.806346e-5; // 11.0 to 20.0 km + // We could put more code for higher altitudes here. +} + + +// Convert altitude to air pressure by ICAO Standard Atmosphere +double altFtToPressInHg(double alt_ft) +{ + // Ref. Aviation Formulary, Ed Williams, www.best.com/~williams/avform.htm + const double P_0 = 29.92126; // Std. MSL pressure, inHg. (=1013.25 mb) + const double p_Tr = 0.2233609 * P_0; // Pressure at tropopause, same units. + const double h_Tr = 36089.24; // Alt of tropopause, ft. (=11.0 km) + + if (alt_ft < h_Tr) // 0.0 to 11.0 km + return P_0 * pow(1.0 - 6.8755856e-6 * alt_ft, 5.2558797); + return p_Tr * exp(-4.806346e-5 * (alt_ft - h_Tr)); // 11.0 to 20.0 km + // We could put more code for higher altitudes here. +} + + //////////////////////////////////////////////////////////////////////// // Here the fun really begins @@ -135,9 +200,10 @@ void FGSteam::set_lowpass ( double *outthe, double inthe, double tc ) void FGSteam::_CatchUp() { if ( _UpdatesPending != 0 ) - { double dt = _UpdatesPending * 1.0 / current_options.get_model_hz(); + { double dt = _UpdatesPending * 1.0 / + fgGetInt("/sim/model-hz"); // FIXME: inefficient double AccN, AccE, AccU; - int i /*,j*/; + /* int i, j; */ double d, the_ENGINE_rpm; #if 0 @@ -147,7 +213,7 @@ void FGSteam::_CatchUp() just to be on the safe side. Doing it more than once will waste CPU time but doesn't hurt anything really. */ - if ( _UpdatesPending == 999 ) + if ( _UpdatesPending > 999999 ) { FGFeature::register_int ( "Avionics/NAV1/Localizer", &NAV1_LOC ); FGFeature::register_double ( "Avionics/NAV1/Latitude", &NAV1_Lat ); FGFeature::register_double ( "Avionics/NAV1/Longitude", &NAV1_Lon ); @@ -182,7 +248,6 @@ void FGSteam::_CatchUp() More subtle flaw is having it not move or a travel limit occasionally due to some dirt in the tube or on the ball. */ - // the_TC_rad = - ( FGBFI::getSideSlip () ); /* incorrect */ d = - current_aircraft.fdm_state->get_A_Z_pilot(); if ( d < 1 ) d = 1; set_lowpass ( & the_TC_rad, @@ -198,9 +263,9 @@ void FGSteam::_CatchUp() */ set_lowpass ( & the_TC_std, current_aircraft.fdm_state->get_Phi_dot () - * RAD_TO_DEG / 20.0 + + * SGD_RADIANS_TO_DEGREES / 20.0 + current_aircraft.fdm_state->get_Psi_dot () - * RAD_TO_DEG / 3.0 , dt ); + * SGD_RADIANS_TO_DEGREES / 3.0 , dt ); /************************** We want to know the pilot accelerations, @@ -210,18 +275,20 @@ void FGSteam::_CatchUp() AccE = current_aircraft.fdm_state->get_V_dot_east(); AccU = current_aircraft.fdm_state->get_V_dot_down() - 9.81 / 0.3; - if ( fabs(the_TC_rad) > 0.2 ) + if ( fabs(the_TC_rad) > 0.2 /* 2.0 */ ) { /* Massive sideslip jams it; it stops turning */ the_MH_degps = 0.0; - the_MH_err = FGBFI::getHeading () - the_MH_deg; + the_MH_err = fgGetDouble("/orientation/heading-deg") - the_MH_deg; } else { double MagDip, MagVar, CosDip; double FrcN, FrcE, FrcU, AccTot; double EdgN, EdgE, EdgU; double TrqN, TrqE, TrqU, Torque; /* Find a force vector towards exact magnetic north */ - MagVar = FGBFI::getMagVar() / RAD_TO_DEG; - MagDip = FGBFI::getMagDip() / RAD_TO_DEG; + MagVar = fgGetDouble("/environment/magnetic-variation-deg") + / SGD_RADIANS_TO_DEGREES; + MagDip = fgGetDouble("/environment/magnetic-dip-deg") + / SGD_RADIANS_TO_DEGREES; CosDip = cos ( MagDip ); FrcN = CosDip * cos ( MagVar ); FrcE = CosDip * sin ( MagVar ); @@ -232,8 +299,8 @@ void FGSteam::_CatchUp() if ( AccTot > 1.0 ) AccTot = sqrt ( AccTot ); else AccTot = 1.0; /* Force applies to north marking on compass card */ - EdgN = cos ( the_MH_err / RAD_TO_DEG ); - EdgE = sin ( the_MH_err / RAD_TO_DEG ); + EdgN = cos ( the_MH_err / SGD_RADIANS_TO_DEGREES ); + EdgE = sin ( the_MH_err / SGD_RADIANS_TO_DEGREES ); EdgU = 0.0; /* Apply the force to the edge to get torques */ TrqN = EdgE * FrcU - EdgU * FrcE; @@ -251,7 +318,7 @@ void FGSteam::_CatchUp() } if ( the_MH_err > 180.0 ) the_MH_err -= 360.0; else if ( the_MH_err < -180.0 ) the_MH_err += 360.0; - the_MH_deg = FGBFI::getHeading () - the_MH_err; + the_MH_deg = fgGetDouble("/orientation/heading-deg") - the_MH_err; } /************************** @@ -259,26 +326,17 @@ void FGSteam::_CatchUp() scaling capability for the vacuum pump later on. When we have a real engine model, we can ask it. */ - the_ENGINE_rpm = FGBFI::getThrottle() * 26.0; - - /************************** - This is just temporary, until the static source works, - so we just filter the actual value by one second to - account for the line impedance of the plumbing. - */ - set_lowpass ( & the_ALT_ft, FGBFI::getAltitude(), dt ); + the_ENGINE_rpm = globals->get_controls()->get_throttle(0) * 26.0; /************************** First, we need to know what the static line is reporting, which is a whole simulation area in itself. For now, we cheat. + We filter the actual value by one second to + account for the line impedance of the plumbing. */ - the_STATIC_inhg = 29.92; - i = (int) the_ALT_ft; - while ( i > 9000 ) - { the_STATIC_inhg *= 0.707; - i -= 9000; - } - the_STATIC_inhg *= ( 1.0 - 0.293 * i / 9000.0 ); + double static_inhg + = altFtToPressInHg(fgGetDouble("/position/altitude-ft")); + set_lowpass ( & the_STATIC_inhg, static_inhg, dt ); /* NO alternate static source error (student feature), @@ -286,6 +344,21 @@ void FGSteam::_CatchUp() NO slip-induced error, important for C172 for example. */ + /************************** + Altimeter. + ICAO standard atmosphere MSL pressure is 1013.25 mb, and pressure + gradient is about 28 ft per mb at MSL increasing to about 32 at + 5000 and 38 at 10000 ft. + Standard altimeters apply the subscale offset to the output altitude, + not to the input pressure; I don't know exactly what pressure gradient + they assume for this. I choose to make it accurate at low altitudes. + Remember, we are trying to simulate a real altimeter, not an ideal one. + */ + set_lowpass ( & the_ALT_ft, + pressInHgToAltFt(the_STATIC_inhg) + + (the_ALT_datum_mb - 1013.25) * 28.0, /* accurate at low alt. */ + dt * 10 ); /* smoothing time 0.1 s */ + /************************** The VSI case is a low-pass filter of the static line pressure. The instrument reports the difference, scaled to approx ft. @@ -321,13 +394,11 @@ void FGSteam::_CatchUp() > have it tumble when you exceed the usual pitch or bank limits, > put in those insidious turning errors ... for now anyway. */ - // cout << "Updates pending = " << _UpdatesPending << endl; - if ( _UpdatesPending > 999 ) { - the_DG_err = FGBFI::getMagVar(); - } - the_DG_degps = 0.0; /* HACK! */ + if ( _UpdatesPending > 999999 ) + the_DG_err = fgGetDouble("/environment/magnetic-variation-deg"); + the_DG_degps = 0.01; /* HACK! */ if (dt<1.0) the_DG_err += dt * the_DG_degps; - the_DG_deg = FGBFI::getHeading () - the_DG_err; + the_DG_deg = fgGetDouble("/orientation/heading-deg") - the_DG_err; /************************** Finished updates, now clear the timer @@ -344,14 +415,17 @@ void FGSteam::_CatchUp() //////////////////////////////////////////////////////////////////////// +#if 0 + double FGSteam::get_HackGS_deg () { if ( current_radiostack->get_nav1_inrange() && current_radiostack->get_nav1_has_gs() ) { double x = current_radiostack->get_nav1_gs_dist(); - double y = (FGBFI::getAltitude() - current_radiostack->get_nav1_elev()) - * FEET_TO_METER; - double angle = atan2( y, x ) * RAD_TO_DEG; + double y = (fgGetDouble("/position/altitude-ft") + - current_radiostack->get_nav1_elev()) + * SG_FEET_TO_METER; + double angle = atan2( y, x ) * SGD_RADIANS_TO_DEGREES; return (current_radiostack->get_nav1_target_gs() - angle) * 5.0; } else { return 0.0; @@ -363,14 +437,8 @@ double FGSteam::get_HackVOR1_deg () { double r; if ( current_radiostack->get_nav1_inrange() ) { - if ( current_radiostack->get_nav1_loc() ) { - // localizer doesn't need magvar offset - r = current_radiostack->get_nav1_heading() - - current_radiostack->get_nav1_radial(); - } else { - r = current_radiostack->get_nav1_heading() - FGBFI::getMagVar() - - current_radiostack->get_nav1_radial(); - } + r = current_radiostack->get_nav1_heading() + - current_radiostack->get_nav1_radial(); // cout << "Radial = " << current_radiostack->get_nav1_radial() // << " Bearing = " << current_radiostack->get_nav1_heading() // << endl; @@ -393,14 +461,8 @@ double FGSteam::get_HackVOR2_deg () { double r; if ( current_radiostack->get_nav2_inrange() ) { - if ( current_radiostack->get_nav2_loc() ) { - // localizer doesn't need magvar offset - r = current_radiostack->get_nav2_heading() - - current_radiostack->get_nav2_radial(); - } else { - r = current_radiostack->get_nav2_heading() - FGBFI::getMagVar() - - current_radiostack->get_nav2_radial(); - } + r = current_radiostack->get_nav2_heading() + - current_radiostack->get_nav2_radial(); // cout << "Radial = " << current_radiostack->get_nav1_radial() // << " Bearing = " << current_radiostack->get_nav1_heading() << endl; @@ -414,6 +476,7 @@ double FGSteam::get_HackVOR2_deg () { return r; } +#endif double FGSteam::get_HackOBS1_deg () { @@ -427,18 +490,18 @@ double FGSteam::get_HackOBS2_deg () { double FGSteam::get_HackADF_deg () { - double r; + static double last_r = 0; if ( current_radiostack->get_adf_inrange() ) { - r = current_radiostack->get_adf_heading() - FGBFI::getHeading(); - + double r = current_radiostack->get_adf_heading() + - fgGetDouble("/orientation/heading-deg"); + last_r = r; // cout << "Radial = " << current_radiostack->get_adf_heading() // << " Heading = " << FGBFI::getHeading() << endl; + return r; } else { - r = 0.0; + return last_r; } - - return r; }