src/AIModel/performancedata.cxx

   1
   2 #ifdef HAVE_CONFIG_H
   3 #  include "config.h"
   4 #endif
   5
   6 #include "performancedata.hxx"
   7 #include "AIAircraft.hxx"
   8
   9
  10 // For now, make this a define
  11 // Later on, additional class variables can simulate settings such as braking power
  12 // also, the performance parameters can be tweaked a little to add some personality
  13 // to the AIAircraft.
  14 #define BRAKE_SETTING 1.6
  15
  16 PerformanceData::PerformanceData(double acceleration,
  17                                 double deceleration,
  18                                 double climbRate,
  19                                 double descentRate,
  20                                 double vRotate,
  21                                 double vTakeOff,
  22                                 double vClimb,
  23                                 double vCruise,
  24                                 double vDescent,
  25                                 double vApproach,
  26                                 double vTouchdown,
  27                                 double vTaxi) :
  28     _acceleration(acceleration),
  29     _deceleration(deceleration),
  30     _climbRate(climbRate),
  31     _descentRate(descentRate),
  32     _vRotate(vRotate),
  33     _vTakeOff(vTakeOff),
  34     _vClimb(vClimb),
  35     _vCruise(vCruise),
  36     _vDescent(vDescent),
  37     _vApproach(vApproach),
  38     _vTouchdown(vTouchdown),
  39     _vTaxi(vTaxi)
  40 {
  41     _rollrate = 9.0; // degrees per second
  42     _maxbank = 30.0; // passenger friendly bank angle
  43 }
  44
  45 // read perf data from file
  46 PerformanceData::PerformanceData( const std::string& filename)
  47 {}
  48
  49 PerformanceData::~PerformanceData()
  50 {}
  51
  52 double PerformanceData::actualSpeed(FGAIAircraft* ac, double tgt_speed, double dt, bool maxBrakes) {
  53     // if (tgt_speed > _vTaxi & ac->onGround()) // maximum taxi speed on ground
  54     //    tgt_speed = _vTaxi;
  55     // bad idea for a take off roll :-)
  56
  57     double speed = ac->getSpeed();
  58     double speed_diff = tgt_speed - speed;
  59
  60     if (speed_diff > 0.0)        // need to accelerate
  61     {
  62         speed += _acceleration * dt;
  63         if ( speed > tgt_speed )
  64             speed = tgt_speed;
  65
  66     } else if (speed_diff < 0.0) { // decelerate
  67         if (ac->onGround()) {
  68             // deceleration performance is better due to wheel brakes.
  69             double brakePower = 0;
  70             if (maxBrakes) {
  71                 brakePower = 3;
  72             } else {
  73                 brakePower = BRAKE_SETTING;
  74             }
  75             speed -= brakePower * _deceleration * dt;
  76         } else {
  77             speed -= _deceleration * dt;
  78         }
  79
  80         if ( speed < tgt_speed )
  81             speed = tgt_speed;
  82
  83     }
  84
  85     return speed;
  86 }
  87
  88 double PerformanceData::actualBankAngle(FGAIAircraft* ac, double tgt_roll, double dt) {
  89     // check maximum bank angle
  90     if (fabs(tgt_roll) > _maxbank)
  91         tgt_roll = _maxbank * tgt_roll/fabs(tgt_roll);
  92
  93     double roll = ac->getRoll();
  94     double bank_diff = tgt_roll - roll;
  95
  96     if (fabs(bank_diff) > 0.2) {
  97         if (bank_diff > 0.0) {
  98             roll += _rollrate * dt;
  99             if (roll > tgt_roll)
 100                 roll = tgt_roll;
 101         }
 102         else if (bank_diff < 0.0) {
 103             roll -= _rollrate * dt;
 104
 105             if (roll < tgt_roll)
 106                 roll = tgt_roll;
 107         }
 108         //while (roll > 180) roll -= 360;
 109         //while (roll < 180) roll += 360;
 110     }
 111
 112     return roll;
 113 }
 114
 115 double PerformanceData::actualPitch(FGAIAircraft* ac, double tgt_pitch, double dt) {
 116     double pitch = ac->getPitch();
 117     double pdiff = tgt_pitch - pitch;
 118
 119     if (pdiff > 0.0) { // nose up
 120         pitch += 0.005*_climbRate * dt / 3.0; //TODO avoid hardcoded 3 secs
 121
 122         if (pitch > tgt_pitch)
 123             pitch = tgt_pitch;
 124     } else if (pdiff < 0.0) { // nose down
 125         pitch -= 0.002*_descentRate * dt / 3.0;
 126
 127         if (pitch < tgt_pitch)
 128             pitch = tgt_pitch;
 129     }
 130
 131     return pitch;
 132 }
 133
 134 double PerformanceData::actualAltitude(FGAIAircraft* ac, double tgt_altitude, double dt) {
 135     if (ac->onGround()) {
 136         //FIXME: a return sensible value here
 137         return 0.0; // 0 for now to avoid compiler errors
 138     } else
 139         return ac->getAltitude() + ac->getVerticalSpeed()*dt/60.0;
 140 }
 141
 142 double PerformanceData::actualVerticalSpeed(FGAIAircraft* ac, double tgt_vs, double dt) {
 143     double vs = ac->getVerticalSpeed();
 144     double vs_diff = tgt_vs - vs;
 145
 146     if (fabs(vs_diff) > .001) {
 147         if (vs_diff > 0.0) {
 148             vs += _climbRate * dt / 3.0; //TODO avoid hardcoded 3 secs to attain climb rate from level flight
 149
 150             if (vs > tgt_vs)
 151                 vs = tgt_vs;
 152         } else if (vs_diff < 0.0) {
 153             vs -= _descentRate * dt / 3.0;
 154
 155             if (vs < tgt_vs)
 156                 vs = tgt_vs;
 157         }
 158     }
 159
 160     return vs;
 161 }
 162
 163 bool PerformanceData::gearExtensible(const FGAIAircraft* ac) {
 164     return (ac->altitudeAGL() < 900.0)
 165             && (ac->airspeed() < _vTouchdown * 1.25);
 166 }