fc84045169
Cleaned a bit of cruft out of gui.[ch]xx Cleaned up win_ratio() and fov code to make more sense and be a bit more consistant and robust and less buggy and less susceptible to screw ups. Panel is activated now by default, HUD is off by default.
443 lines
14 KiB
C++
443 lines
14 KiB
C++
// steam.cxx - Steam Gauge Calculations
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//
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// Copyright (C) 2000 Alexander Perry - alex.perry@ieee.org
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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//
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// $Id$
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#if defined( FG_HAVE_NATIVE_SGI_COMPILERS )
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# include <iostream.h>
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#else
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# include <iostream>
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#endif
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#include <simgear/constants.h>
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#include <simgear/math/fg_types.hxx>
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#include <Aircraft/aircraft.hxx>
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#include <Main/options.hxx>
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#include <Main/bfi.hxx>
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#include <NetworkOLK/features.hxx>
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FG_USING_NAMESPACE(std);
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#include "radiostack.hxx"
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#include "steam.hxx"
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////////////////////////////////////////////////////////////////////////
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// Declare the functions that read the variables
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////////////////////////////////////////////////////////////////////////
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// Anything that reads the BFI directly is not implemented at all!
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double FGSteam::the_STATIC_inhg = 29.92;
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double FGSteam::the_ALT_ft = 0.0;
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double FGSteam::get_ALT_ft() { _CatchUp(); return the_ALT_ft; }
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double FGSteam::get_ASI_kias() { return FGBFI::getAirspeed(); }
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double FGSteam::the_VSI_case = 29.92;
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double FGSteam::the_VSI_fps = 0.0;
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double FGSteam::get_VSI_fps() { _CatchUp(); return the_VSI_fps; }
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double FGSteam::the_VACUUM_inhg = 0.0;
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double FGSteam::get_VACUUM_inhg() { _CatchUp(); return the_VACUUM_inhg; }
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double FGSteam::the_MH_err = 0.0;
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double FGSteam::the_MH_deg = 0.0;
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double FGSteam::the_MH_degps = 0.0;
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double FGSteam::get_MH_deg () { _CatchUp(); return the_MH_deg; }
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double FGSteam::the_DG_err = 0.0;
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double FGSteam::the_DG_deg = 0.0;
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double FGSteam::the_DG_degps = 0.0;
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double FGSteam::the_DG_inhg = 0.0;
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double FGSteam::get_DG_deg () { _CatchUp(); return the_DG_deg; }
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double FGSteam::get_DG_err () { _CatchUp(); return the_DG_err; }
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void FGSteam::set_DG_err ( double approx_magvar ) {
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the_DG_err = approx_magvar;
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}
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double FGSteam::the_TC_rad = 0.0;
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double FGSteam::the_TC_std = 0.0;
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double FGSteam::get_TC_rad () { _CatchUp(); return the_TC_rad; }
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double FGSteam::get_TC_std () { _CatchUp(); return the_TC_std; }
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////////////////////////////////////////////////////////////////////////
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// Recording the current time
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////////////////////////////////////////////////////////////////////////
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int FGSteam::_UpdatesPending = 1000000; /* Forces filter to reset */
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void FGSteam::update ( int timesteps )
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{
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_UpdatesPending += timesteps;
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}
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void FGSteam::set_lowpass ( double *outthe, double inthe, double tc )
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{
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if ( tc < 0.0 )
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{ if ( tc < -1.0 )
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{ /* time went backwards; kill the filter */
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(*outthe) = inthe;
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} else
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{ /* ignore mildly negative time */
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}
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} else
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if ( tc < 0.2 )
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{ /* Normal mode of operation */
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(*outthe) = (*outthe) * ( 1.0 - tc )
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+ inthe * tc;
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} else
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if ( tc > 5.0 )
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{ /* Huge time step; assume filter has settled */
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(*outthe) = inthe;
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} else
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{ /* Moderate time step; non linear response */
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double keep = exp ( -tc );
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// printf ( "ARP: Keep is %f\n", keep );
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(*outthe) = (*outthe) * keep
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+ inthe * ( 1.0 - keep );
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}
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}
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////////////////////////////////////////////////////////////////////////
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// Here the fun really begins
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////////////////////////////////////////////////////////////////////////
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void FGSteam::_CatchUp()
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{ if ( _UpdatesPending != 0 )
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{ double dt = _UpdatesPending * 1.0 / current_options.get_model_hz();
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double AccN, AccE, AccU;
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int i /*,j*/;
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double d, the_ENGINE_rpm;
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#if 0
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/**************************
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There is the possibility that this is the first call.
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If this is the case, we will emit the feature registrations
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just to be on the safe side. Doing it more than once will
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waste CPU time but doesn't hurt anything really.
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*/
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if ( _UpdatesPending > 999999 )
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{ FGFeature::register_int ( "Avionics/NAV1/Localizer", &NAV1_LOC );
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FGFeature::register_double ( "Avionics/NAV1/Latitude", &NAV1_Lat );
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FGFeature::register_double ( "Avionics/NAV1/Longitude", &NAV1_Lon );
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FGFeature::register_double ( "Avionics/NAV1/Radial", &NAV1_Rad );
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FGFeature::register_double ( "Avionics/NAV1/Altitude", &NAV1_Alt );
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FGFeature::register_int ( "Avionics/NAV2/Localizer", &NAV2_LOC );
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FGFeature::register_double ( "Avionics/NAV2/Latitude", &NAV2_Lat );
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FGFeature::register_double ( "Avionics/NAV2/Longitude", &NAV2_Lon );
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FGFeature::register_double ( "Avionics/NAV2/Radial", &NAV2_Rad );
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FGFeature::register_double ( "Avionics/NAV2/Altitude", &NAV2_Alt );
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FGFeature::register_double ( "Avionics/ADF/Latitude", &ADF_Lat );
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FGFeature::register_double ( "Avionics/ADF/Longitude", &ADF_Lon );
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}
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#endif
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/**************************
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Someone has called our update function and
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it turns out that we are running somewhat behind.
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Here, we recalculate everything for a 'dt' second step.
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*/
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/**************************
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The ball responds to the acceleration vector in the body
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frame, only the components perpendicular to the longitudinal
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axis of the aircraft. This is only related to actual
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side slip for a symmetrical aircraft which is not touching
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the ground and not changing its attitude. Math simplifies
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by assuming (for small angles) arctan(x)=x in radians.
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Obvious failure mode is the absence of liquid in the
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tube, which is there to damp the motion, so that instead
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the ball will bounce around, hitting the tube ends.
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More subtle flaw is having it not move or a travel limit
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occasionally due to some dirt in the tube or on the ball.
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*/
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// the_TC_rad = - ( FGBFI::getSideSlip () ); /* incorrect */
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d = - current_aircraft.fdm_state->get_A_Z_pilot();
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if ( d < 1 ) d = 1;
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set_lowpass ( & the_TC_rad,
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current_aircraft.fdm_state->get_A_Y_pilot () / d,
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dt );
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/**************************
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The rate of turn indication is from an electric gyro.
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We should have it spin up with the master switch.
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It is mounted at a funny angle so that it detects
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both rate of bank (i.e. rolling into and out of turns)
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and the rate of turn (i.e. how fast heading is changing).
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*/
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set_lowpass ( & the_TC_std,
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current_aircraft.fdm_state->get_Phi_dot ()
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* RAD_TO_DEG / 20.0 +
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current_aircraft.fdm_state->get_Psi_dot ()
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* RAD_TO_DEG / 3.0 , dt );
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/**************************
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We want to know the pilot accelerations,
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to compute the magnetic compass errors.
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*/
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AccN = current_aircraft.fdm_state->get_V_dot_north();
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AccE = current_aircraft.fdm_state->get_V_dot_east();
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AccU = current_aircraft.fdm_state->get_V_dot_down()
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- 9.81 / 0.3;
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if ( fabs(the_TC_rad) > 0.2 )
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{ /* Massive sideslip jams it; it stops turning */
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the_MH_degps = 0.0;
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the_MH_err = FGBFI::getHeading () - the_MH_deg;
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} else
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{ double MagDip, MagVar, CosDip;
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double FrcN, FrcE, FrcU, AccTot;
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double EdgN, EdgE, EdgU;
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double TrqN, TrqE, TrqU, Torque;
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/* Find a force vector towards exact magnetic north */
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MagVar = FGBFI::getMagVar() / RAD_TO_DEG;
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MagDip = FGBFI::getMagDip() / RAD_TO_DEG;
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CosDip = cos ( MagDip );
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FrcN = CosDip * cos ( MagVar );
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FrcE = CosDip * sin ( MagVar );
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FrcU = sin ( MagDip );
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/* Rotation occurs around acceleration axis,
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but axis magnitude is irrelevant. So compute it. */
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AccTot = AccN*AccN + AccE*AccE + AccU*AccU;
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if ( AccTot > 1.0 ) AccTot = sqrt ( AccTot );
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else AccTot = 1.0;
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/* Force applies to north marking on compass card */
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EdgN = cos ( the_MH_err / RAD_TO_DEG );
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EdgE = sin ( the_MH_err / RAD_TO_DEG );
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EdgU = 0.0;
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/* Apply the force to the edge to get torques */
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TrqN = EdgE * FrcU - EdgU * FrcE;
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TrqE = EdgU * FrcN - EdgN * FrcU;
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TrqU = EdgN * FrcE - EdgE * FrcN;
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/* Select the component parallel to the axis */
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Torque = ( TrqN * AccN +
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TrqE * AccE +
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TrqU * AccU ) * 5.0 / AccTot;
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/* The magnetic compass has angular momentum,
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so we apply a torque to it and wait */
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if ( dt < 1.0 )
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{ the_MH_degps= the_MH_degps * (1.0 - dt) - Torque;
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the_MH_err += dt * the_MH_degps;
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}
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if ( the_MH_err > 180.0 ) the_MH_err -= 360.0; else
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if ( the_MH_err < -180.0 ) the_MH_err += 360.0;
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the_MH_deg = FGBFI::getHeading () - the_MH_err;
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}
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/**************************
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This is not actually correct, but provides a
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scaling capability for the vacuum pump later on.
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When we have a real engine model, we can ask it.
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*/
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the_ENGINE_rpm = FGBFI::getThrottle() * 26.0;
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/**************************
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This is just temporary, until the static source works,
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so we just filter the actual value by one second to
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account for the line impedance of the plumbing.
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*/
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set_lowpass ( & the_ALT_ft, FGBFI::getAltitude(), dt );
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/**************************
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First, we need to know what the static line is reporting,
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which is a whole simulation area in itself. For now, we cheat.
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*/
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the_STATIC_inhg = 29.92;
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i = (int) the_ALT_ft;
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while ( i > 9000 )
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{ the_STATIC_inhg *= 0.707;
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i -= 9000;
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}
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the_STATIC_inhg *= ( 1.0 - 0.293 * i / 9000.0 );
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/*
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NO alternate static source error (student feature),
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NO possibility of blockage (instructor feature),
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NO slip-induced error, important for C172 for example.
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*/
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/**************************
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The VSI case is a low-pass filter of the static line pressure.
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The instrument reports the difference, scaled to approx ft.
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NO option for student to break glass when static source fails.
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NO capability for a fixed non-zero reading when level.
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NO capability to have a scaling error of maybe a factor of two.
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*/
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the_VSI_fps = ( the_VSI_case - the_STATIC_inhg )
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* 10000.0; /* manual scaling factor */
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set_lowpass ( & the_VSI_case, the_STATIC_inhg, dt/6.0 );
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/**************************
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The engine driven vacuum pump is directly attached
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to the engine shaft, so each engine rotation pumps
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a fixed volume. The amount of air in that volume
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is determined by the vacuum line's internal pressure.
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The instruments are essentially leaking air like
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a fixed source impedance from atmospheric pressure.
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The regulator provides a digital limit setting,
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which is open circuit unless the pressure drop is big.
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Thus, we can compute the vacuum line pressure directly.
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We assume that there is negligible reservoir space.
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NO failure of the pump supported (yet)
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*/
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the_VACUUM_inhg = the_STATIC_inhg *
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the_ENGINE_rpm / ( the_ENGINE_rpm + 10000.0 );
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if ( the_VACUUM_inhg > 5.0 )
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the_VACUUM_inhg = 5.0;
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/*
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> I was merely going to do the engine rpm driven vacuum pump for both
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> the AI and DG, have the gyros spin down down in power off descents,
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> have it tumble when you exceed the usual pitch or bank limits,
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> put in those insidious turning errors ... for now anyway.
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*/
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if ( _UpdatesPending > 999999 )
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the_DG_err = FGBFI::getMagVar();
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the_DG_degps = 0.01; /* HACK! */
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if (dt<1.0) the_DG_err += dt * the_DG_degps;
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the_DG_deg = FGBFI::getHeading () - the_DG_err;
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/**************************
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Finished updates, now clear the timer
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*/
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_UpdatesPending = 0;
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} else {
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// cout << "0 Updates pending" << endl;
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}
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}
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////////////////////////////////////////////////////////////////////////
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// Everything below is a transient hack; expect it to disappear
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////////////////////////////////////////////////////////////////////////
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double FGSteam::get_HackGS_deg () {
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if ( current_radiostack->get_nav1_inrange() &&
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current_radiostack->get_nav1_has_gs() )
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{
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double x = current_radiostack->get_nav1_gs_dist();
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double y = (FGBFI::getAltitude() - current_radiostack->get_nav1_elev())
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* FEET_TO_METER;
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double angle = atan2( y, x ) * RAD_TO_DEG;
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return (current_radiostack->get_nav1_target_gs() - angle) * 5.0;
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} else {
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return 0.0;
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}
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}
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double FGSteam::get_HackVOR1_deg () {
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double r;
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if ( current_radiostack->get_nav1_inrange() ) {
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if ( current_radiostack->get_nav1_loc() ) {
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// localizer doesn't need magvar offset
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r = current_radiostack->get_nav1_heading()
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- current_radiostack->get_nav1_radial();
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} else {
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r = current_radiostack->get_nav1_heading() - FGBFI::getMagVar()
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- current_radiostack->get_nav1_radial();
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}
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// cout << "Radial = " << current_radiostack->get_nav1_radial()
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// << " Bearing = " << current_radiostack->get_nav1_heading()
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// << endl;
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if (r> 180.0) r-=360.0; else
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if (r<-180.0) r+=360.0;
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if ( fabs(r) > 90.0 )
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r = ( r<0.0 ? -r-180.0 : -r+180.0 );
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// According to Robin Peel, the ILS is 4x more sensitive than a vor
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if ( current_radiostack->get_nav1_loc() ) r *= 4.0;
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} else {
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r = 0.0;
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}
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return r;
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}
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double FGSteam::get_HackVOR2_deg () {
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double r;
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if ( current_radiostack->get_nav2_inrange() ) {
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if ( current_radiostack->get_nav2_loc() ) {
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// localizer doesn't need magvar offset
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r = current_radiostack->get_nav2_heading()
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- current_radiostack->get_nav2_radial();
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} else {
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r = current_radiostack->get_nav2_heading() - FGBFI::getMagVar()
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- current_radiostack->get_nav2_radial();
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}
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// cout << "Radial = " << current_radiostack->get_nav1_radial()
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// << " Bearing = " << current_radiostack->get_nav1_heading() << endl;
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if (r> 180.0) r-=360.0; else
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if (r<-180.0) r+=360.0;
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if ( fabs(r) > 90.0 )
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r = ( r<0.0 ? -r-180.0 : -r+180.0 );
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} else {
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r = 0.0;
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}
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return r;
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}
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double FGSteam::get_HackOBS1_deg () {
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return current_radiostack->get_nav1_radial();
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}
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double FGSteam::get_HackOBS2_deg () {
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return current_radiostack->get_nav2_radial();
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}
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double FGSteam::get_HackADF_deg () {
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double r;
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if ( current_radiostack->get_adf_inrange() ) {
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r = current_radiostack->get_adf_heading() - FGBFI::getHeading();
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// cout << "Radial = " << current_radiostack->get_adf_heading()
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// << " Heading = " << FGBFI::getHeading() << endl;
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} else {
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r = 0.0;
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}
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return r;
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}
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// end of steam.cxx
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