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flightgear/src/Instrumentation/mrg.cxx
James Turner f2d6b76b13 Portability: Fix compile errors on MSVC (cmath) 
From Scott (xDraconian)
2015-03-24 11:11:42 -05:00

299 lines
9.9 KiB
C++
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// MRG.cxx - an electrically powered master reference gyro.
// Written by Vivian Meazza based on work by David Megginson, started 2006.
//
// This file is in the Public Domain and comes with no warranty.
// TODO:
// - better spin-up
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <simgear/compiler.h>
#include <simgear/sg_inlines.h>
#include <simgear/math/SGMath.hxx>
#include <iostream>
#include <string>
#include <sstream>
#include <cmath> // fabs()
#include <Main/fg_props.hxx>
#include <Main/util.hxx>
#include "mrg.hxx"
const double MasterReferenceGyro::gravity = -32.1740485564;
using std::string;
MasterReferenceGyro::MasterReferenceGyro ( SGPropertyNode *node ) :
_name(node->getStringValue("name", "master-reference-gyro")),
_num(node->getIntValue("number", 0))
{
}
MasterReferenceGyro::~MasterReferenceGyro ()
{
}
void
MasterReferenceGyro::init ()
{
string branch;
branch = "/instrumentation/" + _name;
_pitch_in_node = fgGetNode("/orientation/pitch-deg", true);
_roll_in_node = fgGetNode("/orientation/roll-deg", true);
_hdg_in_node = fgGetNode("/orientation/heading-deg", true);
_hdg_mag_in_node = fgGetNode("/orientation/heading-magnetic-deg", true);
_pitch_rate_node = fgGetNode("/orientation/pitch-rate-degps", true);
_roll_rate_node = fgGetNode("/orientation/roll-rate-degps", true);
_yaw_rate_node = fgGetNode("/orientation/yaw-rate-degps", true);
//_g_in_node = fgGetNode("/accelerations/pilot/z-accel-fps_sec", true);
_g_in_node = fgGetNode("/accelerations/pilot-g", true);
_electrical_node = fgGetNode("/systems/electrical/outputs/MRG", true);
_hdg_mag_in_node = fgGetNode("/orientation/heading-magnetic-deg", true);
SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
_off_node = node->getChild("off-flag", 0, true);
_pitch_out_node = node->getChild("indicated-pitch-deg", 0, true);
_roll_out_node = node->getChild("indicated-roll-deg", 0, true);
_hdg_out_node = node->getChild("indicated-hdg-deg", 0, true);
_hdg_mag_out_node = node->getChild("indicated-mag-hdg-deg", 0, true);
_pitch_rate_out_node = node->getChild("indicated-pitch-rate-degps", 0, true);
_roll_rate_out_node = node->getChild("indicated-roll-rate-degps", 0, true);
_hdg_rate_out_node = node->getChild("indicated-hdg-rate-degps", 0, true);
_responsiveness_node = node->getChild("responsiveness", 0, true);
_error_out_node = node->getChild("heading-bug-error-deg", 0, true);
_hdg_input_source_node = node->getChild("heading-source", 0, true);
_fast_erect_node = node->getChild("fast-erect", 0, true);
reinit();
}
void
MasterReferenceGyro::reinit ()
{
_last_hdg = 0;
_last_roll = 0;
_last_pitch = 0;
_indicated_hdg = 0;
_indicated_roll = 0;
_indicated_pitch = 0;
_indicated_hdg_rate = 0;
_indicated_roll_rate = 0;
_indicated_pitch_rate = 0;
_erect_time = 180;
_last_g = 1;
_g_error = 10;
_electrical_node->setDoubleValue(0);
_responsiveness_node->setDoubleValue(0.75);
_off_node->setBoolValue(false);
_hdg_input_source_node->setBoolValue(false);
_fast_erect_node->setBoolValue(false);
_g_in_node->setDoubleValue(1);
_gyro.reinit();
}
void
MasterReferenceGyro::bind ()
{
std::ostringstream temp;
string branch;
temp << _num;
branch = "/instrumentation/" + _name + "[" + temp.str() + "]";
fgTie((branch + "/serviceable").c_str(),
&_gyro, &Gyro::is_serviceable, &Gyro::set_serviceable);
fgTie((branch + "/spin").c_str(),
&_gyro, &Gyro::get_spin_norm, &Gyro::set_spin_norm);
}
void
MasterReferenceGyro::unbind ()
{
std::ostringstream temp;
string branch;
temp << _num;
branch = "/instrumentation/" + _name + "[" + temp.str() + "]";
fgUntie((branch + "/serviceable").c_str());
fgUntie((branch + "/spin").c_str());
}
void
MasterReferenceGyro::update (double dt)
{
//sanity check
if (!fgGetBool("/sim/fdm-initialized", false)) {
return;
}
double indicated_roll = 0;
double indicated_pitch = 0;
double indicated_hdg = 0;
double indicated_roll_rate = 0;
double indicated_pitch_rate = 0;
double indicated_hdg_rate = 0;
double hdg = 0;
double erect_time_factor = 1;
const double erect_time = 180;
const double max_g_error = 10.0;
//Get the spin from the gyro
_gyro.set_power_norm( _electrical_node->getDoubleValue()/24 );
_gyro.update(dt);
double spin = _gyro.get_spin_norm();
// set the "off-flag"
if ( _electrical_node->getDoubleValue() > 0 && spin >= 0.25) {
_off_node->setBoolValue(false);
} else {
_off_node->setBoolValue(true);
return;
}
// Get the input values
if(_hdg_input_source_node->getBoolValue()){
hdg = _hdg_in_node->getDoubleValue();
} else {
hdg = _hdg_mag_in_node->getDoubleValue();
}
double roll = _roll_in_node->getDoubleValue();
double pitch = _pitch_in_node->getDoubleValue();
double g = _g_in_node->getDoubleValue()/* / gravity*/;
double roll_rate = _yaw_rate_node->getDoubleValue();
double pitch_rate = _pitch_rate_node->getDoubleValue();
double yaw_rate = _yaw_rate_node->getDoubleValue();
//modulate the input by the spin rate
double responsiveness = spin * spin * spin * spin * spin * spin;
roll = fgGetLowPass( _last_roll, roll, responsiveness );
pitch = fgGetLowPass( _last_pitch , pitch, responsiveness );
if ((hdg - _last_hdg) > 180)
_last_hdg += 360;
if ((hdg - _last_hdg) < -180)
_last_hdg -= 360;
hdg = fgGetLowPass( _last_hdg , hdg, responsiveness );
//but we need to filter the hdg and yaw_rate as well - yuk!
responsiveness = 0.1 / (spin * spin * spin * spin * spin * spin);
yaw_rate = fgGetLowPass( _last_yaw_rate , yaw_rate, responsiveness );
g = fgGetLowPass( _last_g , g, 1.5);
// store the new values
_last_roll = roll;
_last_pitch = pitch;
_last_hdg = hdg;
_last_roll_rate = roll_rate;
_last_pitch_rate = pitch_rate;
_last_yaw_rate = yaw_rate;
_last_g = g;
//the gyro only erects inside limits
if ( fabs ( yaw_rate ) <= 5
&& g <= 1.5 && g >= -0.5){
if ( !_fast_erect_node->getBoolValue() ){
erect_time_factor = 1;
} else {
erect_time_factor = 2;
}
_g_error -= (max_g_error/(erect_time * 0.33)) * dt * erect_time_factor;
} else {
_g_error += (max_g_error /(erect_time * 0.33)) * dt * 2;
//SG_LOG(SG_INSTR, SG_ALERT,_num <<
// " g input " << _g_in_node->getDoubleValue() * gravity
// <<" _erect_time " << _erect_time
// << " yaw " << yaw_rate
// << " pitch " << _pitch_rate_node->getDoubleValue()
// << " roll " << _roll_rate_node->getDoubleValue());
}
//cout << "_g_error "<< _g_error << endl;
_g_error = SGMiscd::clip(_g_error, 0, 10);
// cout << "_g_error clip "<< _g_error << endl;
indicated_roll = _last_roll + _g_error;
indicated_pitch = _last_pitch + _g_error;
indicated_hdg = _last_hdg + _g_error;
indicated_roll_rate = _last_roll_rate;
indicated_pitch_rate = _last_pitch_rate;
indicated_hdg_rate = _last_yaw_rate;
// calculate the difference between the indicated heading
// and the selected heading for use with an autopilot
SGPropertyNode *bnode
= fgGetNode( "/autopilot/settings/heading-bug-deg", false );
if ( bnode ) {
double diff = bnode->getDoubleValue() - indicated_hdg;
if ( diff < -180.0 ) { diff += 360.0; }
if ( diff > 180.0 ) { diff -= 360.0; }
_error_out_node->setDoubleValue( diff );
//SG_LOG(SG_INSTR, SG_ALERT,
//"autopilot input " << bnode->getDoubleValue()
//<< " output " << _error_out_node->getDoubleValue()<<);
}
//smooth the output
double factor = _responsiveness_node->getDoubleValue() * dt;
indicated_roll = fgGetLowPass( _indicated_roll, indicated_roll, factor );
indicated_pitch = fgGetLowPass( _indicated_pitch , indicated_pitch, factor );
//indicated_hdg = fgGetLowPass( _indicated_hdg , indicated_hdg, factor );
indicated_roll_rate = fgGetLowPass( _indicated_roll_rate, indicated_roll_rate, factor );
indicated_pitch_rate = fgGetLowPass( _indicated_pitch_rate , indicated_pitch_rate, factor );
indicated_hdg_rate = fgGetLowPass( _indicated_hdg_rate , indicated_hdg_rate, factor );
// store the new values
_indicated_roll = indicated_roll;
_indicated_pitch = indicated_pitch;
_indicated_hdg = indicated_hdg;
_indicated_roll_rate = indicated_roll_rate;
_indicated_pitch_rate = indicated_pitch_rate;
_indicated_hdg_rate = indicated_hdg_rate;
// add in a gyro underspin "error" if gyro is spinning too slowly
const double spin_thresh = 0.8;
const double max_roll_error = 40.0;
const double max_pitch_error = 12.0;
const double max_hdg_error = 140.0;
double roll_error;
double pitch_error;
double hdg_error;
if ( spin <= spin_thresh ) {
double roll_error_factor = ( spin_thresh - spin ) / spin_thresh;
double pitch_error_factor = ( spin_thresh - spin ) / spin_thresh;
double hdg_error_factor = ( spin_thresh - spin ) / spin_thresh;
roll_error = roll_error_factor * roll_error_factor * max_roll_error;
pitch_error = pitch_error_factor * pitch_error_factor * max_pitch_error;
hdg_error = hdg_error_factor * hdg_error_factor * max_hdg_error;
} else {
roll_error = 0.0;
pitch_error = 0.0;
hdg_error = 0.0;
}
_roll_out_node->setDoubleValue( _indicated_roll + roll_error );
_pitch_out_node->setDoubleValue( _indicated_pitch + pitch_error );
_hdg_out_node->setDoubleValue( _indicated_hdg + hdg_error );
_pitch_rate_out_node ->setDoubleValue( _indicated_pitch_rate );
_roll_rate_out_node ->setDoubleValue( _indicated_roll_rate );
_hdg_rate_out_node ->setDoubleValue( _indicated_hdg_rate );
}
// end of mrg.cxx
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