Make the AI models a bit more intelligent. The Gear should be extended and retracted...

[flightgear.git] / src / Instrumentation / attitude_indicator.cxx

diff --git a/src/Instrumentation/attitude_indicator.cxx b/src/Instrumentation/attitude_indicator.cxx
index 9b6626e8785c6ab6ca3554cab605938dc6699eda..a6cdfba2628a0e66192f4c1e90c9afefcc12455c 100644 (file)
--- a/src/Instrumentation/attitude_indicator.cxx
+++ b/src/Instrumentation/attitude_indicator.cxx
@@ -4,11 +4,13 @@
 // This file is in the Public Domain and comes with no warranty.
 
 // TODO:
-// - tumble
 // - better spin-up
 
+#include <math.h>      // fabs()
+
 #include "attitude_indicator.hxx"
 #include <Main/fg_props.hxx>
+#include <Main/util.hxx>
 
 
 AttitudeIndicator::AttitudeIndicator ()
@@ -24,11 +26,22 @@ AttitudeIndicator::init ()
 {
                                 // TODO: allow index of pump and AI
                                 // to be configured.
-    _serviceable_node =
-        fgGetNode("/instrumentation/attitude-indicator/serviceable", true);
     _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);
+    _caged_node =
+        fgGetNode("/instrumentation/attitude-indicator/caged-flag", true);
+    _tumble_node =
+        fgGetNode("/instrumentation/attitude-indicator/tumble-norm", true);
+    _pitch_int_node =
+        fgGetNode("/instrumentation/attitude-indicator/internal-pitch-deg",
+                  true);
+    _roll_int_node =
+        fgGetNode("/instrumentation/attitude-indicator/internal-roll-deg",
+                  true);
     _pitch_out_node =
         fgGetNode("/instrumentation/attitude-indicator/indicated-pitch-deg",
                   true);
@@ -40,45 +53,97 @@ AttitudeIndicator::init ()
 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)
 {
-                                // First, calculate the bogo-spin from 0 to 1.
-                                // All numbers are made up.
-
-    _spin -= 0.005 * dt;         // spin decays every 0.5% every second.
-
-                                // spin increases up to 25% every second
-                                // if suction is available and the gauge
-                                // is serviceable.
-    if (_serviceable_node->getBoolValue()) {
-        double suction = _suction_node->getDoubleValue();
-        double step = 0.25 * (suction / 5.0) * dt;
-        if ((_spin + step) <= (suction / 5.0))
-            _spin += step;
+                                // If it's caged, it doesn't indicate
+    if (_caged_node->getBoolValue()) {
+        _roll_int_node->setDoubleValue(0.0);
+        _pitch_int_node->setDoubleValue(0.0);
+        return;
     }
-    if (_spin > 1.0)
-        _spin = 1.0;
-    else if (_spin < 0.0)
-        _spin = 0.0;
-
-                                // Next, calculate the indicated roll
-                                // and pitch, introducing errors.
-    double factor = 1.0 - ((1.0 - _spin) * (1.0 - _spin));
+
+                                // 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();
-    roll = 35 + (factor * (roll - 35));
-    pitch = 15 + (factor * (pitch - 15));
 
-    _roll_out_node->setDoubleValue(roll);
-    _pitch_out_node->setDoubleValue(pitch);
+                                // Calculate the tumble for the
+                                // next pass.
+    if (_tumble_flag_node->getBoolValue()) {
+        double tumble = _tumble_node->getDoubleValue();
+        if (fabs(roll) > 45.0) {
+            double target = (fabs(roll) - 45.0) / 45.0;
+            target *= target;   // exponential past +-45 degrees
+            if (roll < 0)
+                target = -target;
+
+            if (fabs(target) > fabs(tumble))
+                tumble = target;
+
+            if (tumble > 1.0)
+                tumble = 1.0;
+            else if (tumble < -1.0)
+                tumble = -1.0;
+        }
+                                    // Reerect in 5 minutes
+        double step = dt/300.0;
+        if (tumble < -step)
+            tumble += step;
+        else if (tumble > step)
+            tumble -= step;
+
+        roll += tumble * 45;
+        _tumble_node->setDoubleValue(tumble);
+    }
+
+    roll = fgGetLowPass(_roll_int_node->getDoubleValue(), roll,
+                        responsiveness);
+    pitch = fgGetLowPass(_pitch_int_node->getDoubleValue(), pitch,
+                         responsiveness);
+
+                                // Assign the new values
+    _roll_int_node->setDoubleValue(roll);
+    _pitch_int_node->setDoubleValue(pitch);
+
+    // 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;
+    double roll_error;
+    double pitch_error;
+    if ( spin <= spin_thresh ) {
+        double roll_error_factor = (spin_thresh - spin) / spin_thresh;
+        double pitch_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;
+    } else {
+        roll_error = 0.0;
+        pitch_error = 0.0;
+    }
+
+    _roll_out_node->setDoubleValue(roll + roll_error);
+    _pitch_out_node->setDoubleValue(pitch + pitch_error);
 }
 
 // end of attitude_indicator.cxx