#include "Math.hpp"
#include "Propeller.hpp"
-#include "PistonEngine.hpp"
+#include "Engine.hpp"
#include "PropEngine.hpp"
namespace yasim {
-PropEngine::PropEngine(Propeller* prop, PistonEngine* eng, float moment)
+PropEngine::PropEngine(Propeller* prop, Engine* eng, float moment)
{
// Start off at 500rpm, because the start code doesn't exist yet
- _omega = 52.3;
+ _omega = 52.3f;
_dir[0] = 1; _dir[1] = 0; _dir[2] = 0;
_variable = false;
+ _gearRatio = 1;
_prop = prop;
_eng = eng;
_moment = moment;
+ _fuel = true;
}
PropEngine::~PropEngine()
delete _eng;
}
+void PropEngine::setMagnetos(int pos)
+{
+ _magnetos = pos;
+}
+
void PropEngine::setAdvance(float advance)
{
_advance = Math::clamp(advance, 0, 1);
}
+void PropEngine::setPropPitch(float proppitch)
+{
+ // update Propeller property
+ _prop->setPropPitch(proppitch);
+}
+
+void PropEngine::setPropFeather(int state)
+{
+ // toggle prop feathering on/off
+ _prop->setPropFeather(state);
+}
+
void PropEngine::setVariableProp(float min, float max)
{
_variable = true;
_maxOmega = max;
}
+bool PropEngine::isRunning()
+{
+ return _eng->isRunning();
+}
+
+bool PropEngine::isCranking()
+{
+ return _eng->isCranking();
+}
+
float PropEngine::getOmega()
{
return _omega;
}
+void PropEngine::setOmega (float omega)
+{
+ _omega = omega;
+}
+
void PropEngine::getThrust(float* out)
{
- for(int i=0; i<3; i++) out[i] = _thrust[i];
+ int i;
+ for(i=0; i<3; i++) out[i] = _thrust[i];
}
void PropEngine::getTorque(float* out)
{
- for(int i=0; i<3; i++) out[i] = _torque[i];
+ int i;
+ for(i=0; i<3; i++) out[i] = _torque[i];
}
void PropEngine::getGyro(float* out)
{
- for(int i=0; i<3; i++) out[i] = _gyro[i];
+ int i;
+ for(i=0; i<3; i++) out[i] = _gyro[i];
}
float PropEngine::getFuelFlow()
_eng->setThrottle(_throttle);
_eng->setMixture(_mixture);
+ _eng->setStarter(false);
+ _eng->setMagnetos(3);
+
+ bool running_state = _eng->isRunning();
+ _eng->setRunning(true);
+
if(_variable) {
_omega = _minOmega + _advance * (_maxOmega - _minOmega);
_prop->modPitch(1e6); // Start at maximum pitch and move down
bool goingUp = false;
float step = 10;
while(true) {
- float etau, ptau, dummy;
- _prop->calc(_rho, speed, _omega, &dummy, &ptau);
- _eng->calc(_P, _T, _omega, &etau, &dummy);
+ float ptau, thrust;
+ _prop->calc(_rho, speed, _omega * _gearRatio, &thrust, &ptau);
+ _eng->calc(_pressure, _temp, _omega);
+ _eng->stabilize();
+
+ // Compute torque as seen by the engine's end of the
+ // gearbox.
+ ptau *= _gearRatio;
+ float etau = _eng->getTorque();
float tdiff = etau - ptau;
+
+ Math::mul3(thrust, _dir, _thrust);
- if(Math::abs(tdiff/_moment) < 0.1)
+ if(Math::abs(tdiff/(_moment * _gearRatio)) < 0.1)
break;
if(tdiff > 0) {
- if(!goingUp) step *= 0.5;
+ if(!goingUp) step *= 0.5f;
goingUp = true;
if(!_variable) _omega += step;
- else _prop->modPitch(1+(step*0.005));
+ else _prop->modPitch(1+(step*0.005f));
} else {
- if(goingUp) step *= 0.5;
+ if(goingUp) step *= 0.5f;
goingUp = false;
if(!_variable) _omega -= step;
- else _prop->modPitch(1-(step*0.005));
+ else _prop->modPitch(1-(step*0.005f));
}
}
+
+ // ...and back off
+ _eng->setRunning(running_state);
+}
+
+void PropEngine::init()
+{
+ _omega = 0.01f;
+ _eng->setStarter(false);
+ _eng->setMagnetos(0);
}
void PropEngine::integrate(float dt)
float propTorque, engTorque, thrust;
_eng->setThrottle(_throttle);
+ _eng->setStarter(_starter);
+ _eng->setMagnetos(_magnetos);
_eng->setMixture(_mixture);
+ _eng->setFuelState(_fuel);
- _prop->calc(_rho, speed, _omega,
- &thrust, &propTorque);
- _eng->calc(_P, _T, _omega, &engTorque, &_fuelFlow);
+ _prop->calc(_rho, speed, _omega * _gearRatio, &thrust, &propTorque);
+ _eng->calc(_pressure, _temp, _omega);
+ _eng->integrate(dt);
+ engTorque = _eng->getTorque();
+ _fuelFlow = _eng->getFuelFlow();
// Turn the thrust into a vector and save it
Math::mul3(thrust, _dir, _thrust);
+ // We do our "RPM" computations on the engine's side of the
+ // world, so modify the moment value accordingly.
+ float momt = _moment * _gearRatio;
+
// Euler-integrate the RPM. This doesn't need the full-on
// Runge-Kutta stuff.
- float rotacc = (engTorque-propTorque)/Math::abs(_moment);
+ float rotacc = (engTorque-propTorque)/Math::abs(momt);
_omega += dt * rotacc;
-
- // Clamp to a 500 rpm idle. This should probably be settable, and
- // needs to go away when the startup code gets written.
- if(_omega < 52.3) _omega = 52.3;
-
- // FIXME: Integrate the propeller governor here, when that gets
- // implemented...
+ if (_omega < 0)
+ _omega = 0 - _omega; // don't allow negative RPM
+ // FIXME: introduce proper windmilling
// Store the total angular momentum into _gyro
- Math::mul3(_omega*_moment, _dir, _gyro);
+ Math::mul3(_omega*momt, _dir, _gyro);
// Accumulate the engine torque, it acts on the body as a whole.
// (Note: engine torque, not propeller torque. They can be
float tau = _moment < 0 ? engTorque : -engTorque;
Math::mul3(tau, _dir, _torque);
- // Play with the variable propeller, but only if the propeller is
- // vaguely stable alread (accelerating less than 100 rpm/s)
- if(_variable && Math::abs(rotacc) < 20) {
- float target = _minOmega + _advance*(_maxOmega-_minOmega);
- float mod = 1.04;
- if(target > _omega) mod = 1/mod;
- float diff = Math::abs(target - _omega);
- if(diff < 1) mod = 1 + (mod-1)*diff;
- if(thrust < 0) mod = 1;
+ // Iterate the propeller governor, if we have one. Since engine
+ // torque is basically constant with RPM, we want to make the
+ // propeller torque at the target RPM equal to the engine by
+ // varying the pitch. Assume the the torque goes as the square of
+ // the RPM (roughly correct) and compute a "target" torque for the
+ // _current_ RPM. Seek to that. This is sort of a continuous
+ // Newton-Raphson, basically.
+ if(_variable) {
+ float targetOmega = _minOmega + _advance*(_maxOmega-_minOmega);
+ float ratio2 = (_omega*_omega)/(targetOmega*targetOmega);
+ float targetTorque = engTorque * ratio2;
+
+ float mod = propTorque < targetTorque ? 1.04f : (1.0f/1.04f);
+
+ // Convert to an acceleration here, so that big propellers
+ // don't seek faster than small ones.
+ float diff = Math::abs((propTorque - targetTorque) / momt);
+ if(diff < 10) mod = 1 + (mod-1)*(0.1f*diff);
+
_prop->modPitch(mod);
}
}
projects / flightgear.git / blobdiff