turn_indicator.cxx

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/*
 * SPDX-FileName: turn_indicator.cxx
 * SPDX-FileComment: an electric-powered turn indicator.
 * SPDX-License-Identifier: GPL-2.0-or-later
 * SPDX-FileContributor:  Written by David Megginson, started 2002.
 * SPDX-FileContributor: Enhanced by Benedikt Hallinger, 2023
 */
 
#include "config.h"
 
#include "turn_indicator.hxx"
 
#include <simgear/compiler.h>
#include <iostream>
#include <string>
#include <sstream>
 
#include <Main/fg_props.hxx>
#include <Main/util.hxx>
 
using std::string;
 
// Use a bigger number to be more responsive, or a smaller number
// to be more sluggish.
#define RESPONSIVENESS 0.5
 
 
TurnIndicator::TurnIndicator ( SGPropertyNode *node) :
    _last_rate(0)
{
    if( !node->getBoolValue("new-default-power-path", 0) ){
       setDefaultPowerSupplyPath("/systems/electrical/outputs/turn-coordinator");
    }
 
    SGPropertyNode* gyro_cfg = node->getChild("gyro", 0, true);
    _gyro_spin_up = gyro_cfg->getDoubleValue("spin-up-sec", 4.0);
    _gyro_spin_down = gyro_cfg->getDoubleValue("spin-down-sec", 180.0);
 
    readConfig(node, "turn-indicator");
}
 
TurnIndicator::~TurnIndicator ()
{
}
 
void
TurnIndicator::init ()
{
    string branch = nodePath();
 
    SGPropertyNode *node = fgGetNode(branch, true );
    _roll_rate_node = fgGetNode("/orientation/roll-rate-degps", true);
    _yaw_rate_node = fgGetNode("/orientation/yaw-rate-degps", true);
    _rate_out_node = node->getChild("indicated-turn-rate", 0, true);
    _spin_node = node->getChild("spin", 0, true);
    SGPropertyNode* gyro_node = node->getChild("gyro", 0, true);
    _gyro_spin_up_node = gyro_node->getChild("spin-up-sec", 0, true);
    _gyro_spin_down_node = gyro_node->getChild("spin-down-sec", 0, true);
    if (!_gyro_spin_up_node->hasValue())
        _gyro_spin_up_node->setDoubleValue(_gyro_spin_up);
    if (!_gyro_spin_down_node->hasValue())
        _gyro_spin_down_node->setDoubleValue(_gyro_spin_down);
 
    initServicePowerProperties(node);
 
    reinit();
}
 
void
TurnIndicator::reinit ()
{
    _last_rate = 0;
    _gyro.reinit();
}
 
void
TurnIndicator::update (double dt)
{
                                // Get the spin from the gyro
    _gyro.set_power_norm(isServiceableAndPowered());
    _gyro.set_spin_up(_gyro_spin_up_node->getDoubleValue());
    _gyro.set_spin_down(_gyro_spin_down_node->getDoubleValue());
    _gyro.set_spin_norm(_spin_node->getDoubleValue());
    _gyro.update(dt);
    double spin = _gyro.get_spin_norm();
    _spin_node->setDoubleValue( spin );
 
                                // Calculate the indicated rate
    double factor = 1.0 - ((1.0 - spin) * (1.0 - spin) * (1.0 - spin));
    double rate = ((_roll_rate_node->getDoubleValue() / 20.0) +
                   (_yaw_rate_node->getDoubleValue() / 3.0));
 
                                // Clamp the rate
    if (rate < -2.5)
        rate = -2.5;
    else if (rate > 2.5)
        rate = 2.5;
 
                                // Lag left, based on gyro spin
    rate = -2.5 + (factor * (rate + 2.5));
    rate = fgGetLowPass(_last_rate, rate, dt*RESPONSIVENESS);
    _last_rate = rate;
    
                                // Publish the indicated rate
    _rate_out_node->setDoubleValue(rate);
}
 
// end of turn_indicator.cxx