X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FInstrumentation%2Fattitude_indicator.cxx;h=a6cdfba2628a0e66192f4c1e90c9afefcc12455c;hb=863b0c943251fae620406ec8983e5f69e1424731;hp=02a249e4c3a6991fa8a3b4e06d032a6489653c6e;hpb=677c3e3e9ab9598c40a23cc89f99235d618b3a6f;p=flightgear.git

diff --git a/src/Instrumentation/attitude_indicator.cxx b/src/Instrumentation/attitude_indicator.cxx
index 02a249e4c..a6cdfba26 100644
--- 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 ()
@@ -27,6 +29,19 @@ AttitudeIndicator::init ()
     _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);
@@ -39,7 +54,7 @@ void
 AttitudeIndicator::bind ()
 {
     fgTie("/instrumentation/attitude-indicator/serviceable",
-          &_gyro, &Gyro::is_serviceable);
+          &_gyro, &Gyro::is_serviceable, &Gyro::set_serviceable);
     fgTie("/instrumentation/attitude-indicator/spin",
           &_gyro, &Gyro::get_spin_norm, &Gyro::set_spin_norm);
 }
@@ -54,21 +69,81 @@ AttitudeIndicator::unbind ()
 void
 AttitudeIndicator::update (double dt)
 {
+                                // 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;
+    }
+
                                 // Get the spin from the gyro
     _gyro.set_power_norm(_suction_node->getDoubleValue()/5.0);
     _gyro.update(dt);
     double spin = _gyro.get_spin_norm();
 
-                                // Next, calculate the indicated roll
-                                // and pitch, introducing errors.
-    double factor = 1.0 - ((1.0 - spin) * (1.0 - spin) * (1.0 - spin));
+                                // 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