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Add a pressure rate helper function for Roy's KAP140 autopilot model.

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curt 2004-04-12 19:17:47 +00:00
parent 7019fcdc15
commit 088a7a83b4
1 changed files with 37 additions and 1 deletions
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38
src/Autopilot/xmlauto.cxx
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@ -26,6 +26,7 @@
#include <Main/fg_props.hxx>
#include <Main/globals.hxx>
#include <Main/util.hxx>
#include "xmlauto.hxx"
@ -773,7 +774,42 @@ static void update_helper( double dt ) {
static SGPropertyNode *vs_fpm
= fgGetNode( "/autopilot/internal/vert-speed-fpm", true );
vs_fpm->setDoubleValue( vs_fps->getDoubleValue() * 60.0 );
vs_fpm->setDoubleValue( vs_fps->getDoubleValue() * 60.0 );
// Calculate static port pressure rate in [inhg/s].
// Used to determine vertical speed.
static SGPropertyNode *static_pressure
= fgGetNode( "/systems/static[0]/pressure-inhg", true );
static SGPropertyNode *pressure_rate
= fgGetNode( "/autopilot/internal/pressure-rate", true );
static SGPropertyNode *filter_time
= fgGetNode( "/autopilot/internal/ft", true );
static double last_static_pressure = 0.0;
static double last_pressure_rate = 0.0;
double Tf = filter_time->getDoubleValue();
if ( dt > 0.0 && Tf > 0.0) {
double current_static_pressure = static_pressure->getDoubleValue();
double current_pressure_rate =
( current_static_pressure - last_static_pressure ) / dt;
double W = dt/Tf;
// Low Pass Filter
current_pressure_rate =
(1.0/(W + 1.0))*last_pressure_rate +
((W)/(W + 1.0))*current_pressure_rate;
pressure_rate->setDoubleValue(current_pressure_rate);
last_static_pressure = current_static_pressure;
last_pressure_rate = current_pressure_rate;
}
}