AI: Fix unit problems for AIBase::vs

It was supposed to be in ft/min, but everything except AIAircraft was
using it as ft/sec. Change the name to AIBase::vs_fps and ensure the
same unit is used everywhere.

src/AIModel/AIAircraft.cxx

@@ -1329,10 +1329,10 @@ void FGAIAircraft::updateActualState(double dt)
     roll = _performance->actualBankAngle(this, tgt_roll, dt);
 
     // adjust altitude (meters) based on current vertical speed (fpm)
-    altitude_ft += vs / 60.0 * dt;
+    altitude_ft += vs_fps * dt;
     pos.setElevationFt(altitude_ft);
 
-    vs = _performance->actualVerticalSpeed(this, tgt_vs, dt);
+    vs_fps = _performance->actualVerticalSpeed(this, tgt_vs, dt) / 60;
     pitch = _performance->actualPitch(this, tgt_pitch, dt);
 }
 

src/AIModel/AIAircraft.hxx

@@ -98,7 +98,7 @@ public:
     inline double getRoll() const { return roll; };
     inline double getPitch() const { return pitch; };
     inline double getAltitude() const { return altitude_ft; };
-    inline double getVerticalSpeed() const { return vs; };
+    inline double getVerticalSpeedFPM() const { return vs_fps * 60; };
     inline double altitudeAGL() const { return props->getFloatValue("position/altitude-agl-ft");};
     inline double airspeed() const { return props->getFloatValue("velocities/airspeed-kt");};
     const std::string& atGate();

src/AIModel/AIBallistic.cxx

@@ -225,7 +225,7 @@ void FGAIBallistic::bind() {
         tie("position/global-z",
             SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getCartPosZ, 0));
         tie("velocities/vertical-speed-fps",
-            SGRawValuePointer<double>(&vs));
+            SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getVS_fps, &FGAIBase::_setVS_fps));
         tie("velocities/true-airspeed-kt",
             SGRawValuePointer<double>(&speed));
         tie("velocities/horizontal-speed-fps",
@@ -780,8 +780,8 @@ void FGAIBallistic::Run(double dt) {
                     normal_force_lbs = 0;
 
                 pos.setElevationFt(0 + _ground_offset);
-                if (vs < 0)
+                if (vs_fps < 0)
-                    vs = -vs * 0.5;
+                    vs_fps *= -0.5;
 
                 // Calculate friction. We assume a static coefficient of
                 // friction (mu) of 0.62 (wood on concrete)
@@ -844,10 +844,10 @@ void FGAIBallistic::Run(double dt) {
 
     // adjust vertical speed for acceleration of gravity, buoyancy, and vertical force
     double gravity = SG_METER_TO_FEET * (Environment::Gravity::instance()->getGravity(pos));
-    vs -= (gravity - _buoyancy - v_force_acc_fpss - normal_force_fpss) * dt;
+    vs_fps -= (gravity - _buoyancy - v_force_acc_fpss - normal_force_fpss) * dt;
 
-    if (vs <= 0.00001 && vs >= -0.00001)
+    if (vs_fps <= 0.00001 && vs_fps >= -0.00001)
-        vs = 0;
+        vs_fps = 0;
 
     // set new position
     if (_slave_load_to_ac) {
@@ -878,19 +878,19 @@ void FGAIBallistic::Run(double dt) {
         pos.setLongitudeDeg( pos.getLongitudeDeg()
             + (speed_east_deg_sec - wind_speed_from_east_deg_sec 
             + force_speed_east_deg_sec + friction_force_speed_east_deg_sec) * dt );
-        pos.setElevationFt(pos.getElevationFt() + vs * dt);
+        pos.setElevationFt(pos.getElevationFt() + vs_fps * dt);
     }
 
 //    cout << _name << " run hs " << hs << " vs " << vs << endl;
 
     // recalculate total speed
-    if ( vs == 0 && hs == 0)
+    if ( vs_fps == 0 && hs == 0)
         speed = 0;
     else
-        speed = sqrt( vs * vs + hs * hs) / SG_KT_TO_FPS;
+        speed = sqrt( vs_fps * vs_fps + hs * hs) / SG_KT_TO_FPS;
 
     // recalculate elevation and azimuth (velocity vectors)
-    _elevation = atan2( vs, hs ) * SG_RADIANS_TO_DEGREES;
+    _elevation = atan2( vs_fps, hs ) * SG_RADIANS_TO_DEGREES;
     _azimuth =  atan2((_speed_east_fps + force_speed_east_fps + friction_force_speed_east_fps), 
         (_speed_north_fps + force_speed_north_fps + friction_force_speed_north_fps))
         * SG_RADIANS_TO_DEGREES;
@@ -1147,10 +1147,10 @@ void FGAIBallistic::calcVSHS() {
     double speed_fps = speed * SG_KT_TO_FPS;
 
     if (speed == 0.0) {
-        hs = vs = 0.0;
+        hs = vs_fps = 0.0;
     }
     else {
-        vs = sin( _elevation * SG_DEGREES_TO_RADIANS ) * speed_fps;
+        vs_fps = sin( _elevation * SG_DEGREES_TO_RADIANS ) * speed_fps;
         hs = cos( _elevation * SG_DEGREES_TO_RADIANS ) * speed_fps;
     }
 }

src/AIModel/AIBase.cxx

@@ -136,7 +136,7 @@ FGAIBase::FGAIBase(object_type ot, bool enableHot) :
     _otype(ot)
 {
     tgt_heading = hdg = tgt_altitude_ft = tgt_speed = 0.0;
-    tgt_roll = roll = tgt_pitch = tgt_yaw = tgt_vs = vs = pitch = 0.0;
+    tgt_roll = roll = tgt_pitch = tgt_yaw = tgt_vs = vs_fps = pitch = 0.0;
     bearing = elevation = range = rdot = 0.0;
     x_shift = y_shift = rotation = 0.0;
     in_range = false;
@@ -946,7 +946,7 @@ double FGAIBase::_getRdot() const {
 }
 
 double FGAIBase::_getVS_fps() const {
-    return vs/60.0;
+    return vs_fps;
 }
 
 double FGAIBase::_get_speed_east_fps() const {
@@ -958,7 +958,7 @@ double FGAIBase::_get_speed_north_fps() const {
 }
 
 void FGAIBase::_setVS_fps( double _vs ) {
-    vs = _vs*60.0;
+    vs_fps = _vs;
 }
 
 double FGAIBase::_getAltitude() const {

src/AIModel/AIBase.hxx

@@ -192,7 +192,7 @@ protected:
     double pitch;       // degrees, nose-down is negative
     double speed;       // knots true airspeed
     double altitude_ft; // feet above sea level
-    double vs;          // vertical speed, feet per minute
+    double vs_fps;      // vertical speed
     double speed_north_deg_sec;
     double speed_east_deg_sec;
     double turn_radius_ft; // turn radius ft at 15 kts rudder angle 15 degrees

src/AIModel/AIMultiplayer.cxx

@@ -521,7 +521,7 @@ void FGAIMultiplayer::update(double dt)
       if (dt < 1.0)
           Weighting = dt;
       // simple smoothing over 1 second
-      vs = (1.0-Weighting)*vs +  Weighting * (altitude_ft - recent_alt_ft) / dT * 60;
+      vs_fps = (1.0-Weighting)*vs_fps +  Weighting * (altitude_ft - recent_alt_ft) / dT * 60;
   }
   lastUpdateTime = curtime;
 

src/AIModel/AIWingman.cxx

@@ -136,7 +136,7 @@ void FGAIWingman::bind() {
         (*this, &FGAIBallistic::getElevHitchToUser));
 
     tie("velocities/vertical-speed-fps",
-        SGRawValuePointer<double>(&vs));
+        SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getVS_fps, &FGAIBase::_setVS_fps));
     tie("velocities/true-airspeed-kt",
         SGRawValuePointer<double>(&speed));
     tie("velocities/speed-east-fps",
@@ -475,9 +475,9 @@ void FGAIWingman::Run(double dt) {
 
     // calculate vertical and horizontal speed components
     if (speed == 0.0) {
-        hs = vs = 0.0;
+        hs = vs_fps = 0.0;
     } else {
-        vs = sin( pitch * SG_DEGREES_TO_RADIANS ) * speed_fps;
+        vs_fps = sin( pitch * SG_DEGREES_TO_RADIANS ) * speed_fps;
         hs = cos( pitch * SG_DEGREES_TO_RADIANS ) * speed_fps;
     }
 
@@ -506,8 +506,8 @@ void FGAIWingman::Run(double dt) {
     if (hs <= 0.00001)
         hs = 0;
 
-    if (vs <= 0.00001 && vs >= -0.00001)
+    if (vs_fps <= 0.00001 && vs_fps >= -0.00001)
-        vs = 0;
+        vs_fps = 0;
 
     //cout << "lat " << pos.getLatitudeDeg()<< endl;
     // set new position
@@ -515,18 +515,18 @@ void FGAIWingman::Run(double dt) {
             + (speed_north_deg_sec - wind_speed_from_north_deg_sec) * dt );
     pos.setLongitudeDeg( pos.getLongitudeDeg()
             + (speed_east_deg_sec - wind_speed_from_east_deg_sec ) * dt );
-    pos.setElevationFt(pos.getElevationFt() + vs * dt);
+    pos.setElevationFt(pos.getElevationFt() + vs_fps * dt);
 
     //cout << _name << " run hs " << hs << " vs " << vs << endl;
 
     // recalculate total speed
-    if ( vs == 0 && hs == 0)
+    if ( vs_fps == 0 && hs == 0)
         speed = 0;
     else
-        speed = sqrt( vs * vs + hs * hs) / SG_KT_TO_FPS;
+        speed = sqrt( vs_fps * vs_fps + hs * hs) / SG_KT_TO_FPS;
 
     // recalculate elevation and azimuth (velocity vectors)
-    pitch = atan2( vs, hs ) * SG_RADIANS_TO_DEGREES;
+    pitch = atan2( vs_fps, hs ) * SG_RADIANS_TO_DEGREES;
     hdg   = atan2((speed_east_fps),(speed_north_fps))* SG_RADIANS_TO_DEGREES;
 
     // rationalise heading

src/AIModel/performancedata.cxx

@@ -188,11 +188,11 @@ double PerformanceData::actualAltitude(FGAIAircraft* ac, double tgt_altitude, do
         //FIXME: a return sensible value here
         return 0.0; // 0 for now to avoid compiler errors
     } else
-        return ac->getAltitude() + ac->getVerticalSpeed()*dt/60.0;
+        return ac->getAltitude() + ac->getVerticalSpeedFPM()*dt/60.0;
 }
 
 double PerformanceData::actualVerticalSpeed(FGAIAircraft* ac, double tgt_vs, double dt) {
-    double vs = ac->getVerticalSpeed();
+    double vs = ac->getVerticalSpeedFPM();
     double vs_diff = tgt_vs - vs;
 
     if (fabs(vs_diff) > .001) {

src/FDM/AIWake/AIWakeGroup.cxx

@@ -64,7 +64,7 @@ void AIWakeGroup::AddAI(FGAIAircraft* ai)
                                                     ai->getPitch(), 0.0);
 
     double hVel = ai->getSpeed()*SG_KT_TO_FPS;
-    double vVel = ai->getVerticalSpeed()/60;
+    double vVel = ai->getVerticalSpeedFPM()/60;
     double gamma = atan2(vVel, hVel);
     double vel = sqrt(hVel*hVel + vVel*vVel);
     double weight = perfData->weight();

test_suite/unit_tests/AI/test_submodels.cxx

@@ -254,7 +254,6 @@ void SubmodelsTests::testInitialState()
                                  * speed
                                  + speed_east,
                                  sm->_get_speed_east_fps(), 0.1);
-    // In AIBase, attribute 'vs' is in fpm, but AIBallistic uses it as fps?!
     CPPUNIT_ASSERT_DOUBLES_EQUAL(sin((pitch + pitch_offset) * SG_DEGREES_TO_RADIANS) * speed,
-                                 sm->_getVS_fps() * 60, 0.1);
+                                 sm->_getVS_fps(), 0.1);
 }