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flightgear/src/Instrumentation/attitude_indicator.cxx
david ad6236cbe7 Add the ability for the AI to tumble in extreme attitudes, if
/instrumentation/attitude-indicator/config/tumble-flag

is true.  The AI will take up to five minutes to reerect itself
completely.
2003-04-04 03:25:02 +00:00

111 lines
3.4 KiB
C++

// attitude_indicator.cxx - a vacuum-powered attitude indicator.
// Written by David Megginson, started 2002.
//
// This file is in the Public Domain and comes with no warranty.
// TODO:
// - better spin-up
#include "attitude_indicator.hxx"
#include <Main/fg_props.hxx>
#include <Main/util.hxx>
AttitudeIndicator::AttitudeIndicator ()
: _tumble(0)
{
}
AttitudeIndicator::~AttitudeIndicator ()
{
}
void
AttitudeIndicator::init ()
{
// TODO: allow index of pump and AI
// to be configured.
_pitch_in_node = fgGetNode("/orientation/pitch-deg", true);
_roll_in_node = fgGetNode("/orientation/roll-deg", true);
_suction_node = fgGetNode("/systems/vacuum[0]/suction-inhg", true);
_tumble_flag_node =
fgGetNode("/instrumentation/attitude-indicator/config/tumble-flag",
true);
_pitch_out_node =
fgGetNode("/instrumentation/attitude-indicator/indicated-pitch-deg",
true);
_roll_out_node =
fgGetNode("/instrumentation/attitude-indicator/indicated-roll-deg",
true);
}
void
AttitudeIndicator::bind ()
{
fgTie("/instrumentation/attitude-indicator/serviceable",
&_gyro, &Gyro::is_serviceable, &Gyro::set_serviceable);
fgTie("/instrumentation/attitude-indicator/spin",
&_gyro, &Gyro::get_spin_norm, &Gyro::set_spin_norm);
}
void
AttitudeIndicator::unbind ()
{
fgUntie("/instrumentation/attitude-indicator/serviceable");
fgUntie("/instrumentation/attitude-indicator/spin");
}
void
AttitudeIndicator::update (double dt)
{
// Get the spin from the gyro
_gyro.set_power_norm(_suction_node->getDoubleValue()/5.0);
_gyro.update(dt);
double spin = _gyro.get_spin_norm();
// Calculate the responsiveness
double responsiveness = spin * spin * spin * spin * spin * spin;
// Get the indicated roll and pitch
double roll = _roll_in_node->getDoubleValue();
double pitch = _pitch_in_node->getDoubleValue();
// Calculate the tumble for the
// next pass.
if (_tumble_flag_node->getBoolValue()) {
if (_tumble < 1.0) {
if (fabs(roll) > 45.0) {
double target = (fabs(roll) - 45.0) / 45.0;
if (_tumble < target)
_tumble = target;
}
if (fabs(pitch) > 45.0) {
double target = (fabs(pitch) - 45.0) / 45.0;
if (_tumble < target)
_tumble = target;
}
if (_tumble > 1.0) {
_tumble = 1.0;
}
}
// Reerect in 5 minutes
_tumble -= dt/300.0;
if (_tumble < 0.0)
_tumble = 0.0;
responsiveness *= ((1.0 - _tumble) * (1.0 - _tumble) *
(1.0 - _tumble) * (1.0 - _tumble));
}
roll = fgGetLowPass(_roll_out_node->getDoubleValue(), roll,
responsiveness);
pitch = fgGetLowPass(_pitch_out_node->getDoubleValue(), pitch,
responsiveness);
// Assign the new values
_roll_out_node->setDoubleValue(roll);
_pitch_out_node->setDoubleValue(pitch);
}
// end of attitude_indicator.cxx