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flightgear/src/FDM/YASim/YASim.cxx
andy 4535c84b99 Solve for the elevator control input during approach. It turns out that 
the downforce from the tail due to elevator trim is a significant contribution
to total lift.
2002-05-21 07:40:46 +00:00

449 lines
13 KiB
C++
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#include <simgear/misc/sg_path.hxx>
#include <simgear/debug/logstream.hxx>
#include <simgear/xml/easyxml.hxx>
#include <Main/globals.hxx>
#include <Main/fg_props.hxx>
#include "FGFDM.hpp"
#include "Atmosphere.hpp"
#include "Math.hpp"
#include "Airplane.hpp"
#include "Model.hpp"
#include "Integrator.hpp"
#include "Glue.hpp"
#include "Gear.hpp"
#include "PropEngine.hpp"
#include "PistonEngine.hpp"
#include "YASim.hxx"
using namespace yasim;
static const float RAD2DEG = 180/3.14159265358979323846;
static const float RAD2RPM = 9.54929658551;
static const float M2FT = 3.2808399;
static const float FT2M = 0.3048;
static const float MPS2KTS = 3600.0/1852.0;
static const float CM2GALS = 264.172037284; // gallons/cubic meter
static const float KG2LBS = 2.20462262185;
static const float W2HP = 1.3416e-3;
static const float INHG2PA = 3386.389;
void YASim::printDEBUG()
{
static int debugCount = 0;
debugCount++;
if(debugCount >= 3) {
debugCount = 0;
// printf("N1 %5.1f N2 %5.1f FF %7.1f EPR %4.2f EGT %6.1f\n",
// fgGetFloat("/engines/engine[0]/n1"),
// fgGetFloat("/engines/engine[0]/n2"),
// fgGetFloat("/engines/engine[0]/fuel-flow-gph"),
// fgGetFloat("/engines/engine[0]/epr"),
// fgGetFloat("/engines/engine[0]/egt"));
// printf("gear: %f\n", fgGetFloat("/controls/gear-down"));
// printf("alpha %5.1f beta %5.1f\n", get_Alpha()*57.3, get_Beta()*57.3);
// printf("pilot: %f %f %f\n",
// fgGetDouble("/sim/view/pilot/x-offset-m"),
// fgGetDouble("/sim/view/pilot/y-offset-m"),
// fgGetDouble("/sim/view/pilot/z-offset-m"));
}
}
YASim::YASim(double dt)
{
// set_delta_t(dt);
_fdm = new FGFDM();
_dt = dt;
_fdm->getAirplane()->getModel()->getIntegrator()->setInterval(_dt);
}
void YASim::report()
{
Airplane* a = _fdm->getAirplane();
float aoa = a->getCruiseAoA() * RAD2DEG;
float tail = -1 * a->getTailIncidence() * RAD2DEG;
float drag = 1000 * a->getDragCoefficient();
SG_LOG(SG_FLIGHT,SG_INFO,"YASim solution results:");
SG_LOG(SG_FLIGHT,SG_INFO," Iterations: "<<a->getSolutionIterations());
SG_LOG(SG_FLIGHT,SG_INFO," Drag Coefficient: "<< drag);
SG_LOG(SG_FLIGHT,SG_INFO," Lift Ratio: "<<a->getLiftRatio());
SG_LOG(SG_FLIGHT,SG_INFO," Cruise AoA: "<< aoa);
SG_LOG(SG_FLIGHT,SG_INFO," Tail Incidence: "<< tail);
SG_LOG(SG_FLIGHT,SG_INFO,"Approach Elevator: "<<a->getApproachElevator());
float cg[3];
char buf[256];
a->getModel()->getBody()->getCG(cg);
sprintf(buf, " CG: %.1f, %.1f, %.1f", cg[0], cg[1], cg[2]);
SG_LOG(SG_FLIGHT, SG_INFO, buf);
if(a->getFailureMsg()) {
SG_LOG(SG_FLIGHT, SG_ALERT, "YASim SOLUTION FAILURE:");
SG_LOG(SG_FLIGHT, SG_ALERT, a->getFailureMsg());
exit(1);
}
}
void YASim::bind()
{
// Run the superclass bind to set up a bunch of property ties
FGInterface::bind();
// Now UNtie the ones that we are going to set ourselves.
fgUntie("/consumables/fuel/tank[0]/level-gal_us");
fgUntie("/consumables/fuel/tank[1]/level-gal_us");
char buf[256];
for(int i=0; i<_fdm->getAirplane()->getModel()->numThrusters(); i++) {
sprintf(buf, "/engines/engine[%d]/fuel-flow-gph", i); fgUntie(buf);
sprintf(buf, "/engines/engine[%d]/rpm", i); fgUntie(buf);
sprintf(buf, "/engines/engine[%d]/mp-osi", i); fgUntie(buf);
sprintf(buf, "/engines/engine[%d]/egt-degf", i); fgUntie(buf);
}
}
void YASim::init()
{
Airplane* a = _fdm->getAirplane();
Model* m = a->getModel();
// Superclass hook
common_init();
m->setCrashed(false);
// Build a filename and parse it
SGPath f(globals->get_fg_root());
f.append("Aircraft-yasim");
f.append(fgGetString("/sim/aero"));
f.concat(".xml");
readXML(f.str(), *_fdm);
// Compile it into a real airplane, and tell the user what they got
a->compile();
report();
_fdm->init();
// Create some FG{Eng|Gear}Interface objects
int i;
for(i=0; i<a->numGear(); i++) {
Gear* g = a->getGear(i);
SGPropertyNode * node = fgGetNode("gear/gear", i, true);
float pos[3];
g->getPosition(pos);
node->setDoubleValue("xoffset-in", pos[0]);
node->setDoubleValue("yoffset-in", pos[1]);
node->setDoubleValue("zoffset-in", pos[2]);
}
for(i=0; i<m->numThrusters(); i++) {
// Sanify the initial input conditions
char buf[64];
sprintf(buf, "/controls/throttle[%d]", i); fgSetFloat(buf, 0);
sprintf(buf, "/controls/mixture[%d]", i); fgSetFloat(buf, 1);
sprintf(buf, "/controls/propeller-pitch[%d]", i); fgSetFloat(buf, 1);
sprintf(buf, "/controls/afterburner[%d]", i); fgSetFloat(buf, 0);
}
fgSetFloat("/controls/slats", 0);
fgSetFloat("/controls/spoilers", 0);
// Are we at ground level? If so, lift the plane up so the gear
// clear the ground.
double runway_altitude = get_Runway_altitude();
fgSetBool("/controls/gear-down", false);
if(get_Altitude() - runway_altitude < 50) {
float minGearZ = 1e18;
for(i=0; i<a->numGear(); i++) {
Gear* g = a->getGear(i);
float pos[3];
g->getPosition(pos);
if(pos[2] < minGearZ)
minGearZ = pos[2];
}
_set_Altitude(runway_altitude - minGearZ*M2FT);
fgSetBool("/controls/gear-down", true);
}
// The pilot's eyepoint
float pilot[3];
a->getPilotPos(pilot);
// fgSetFloat("/sim/view/pilot/x-offset-m", -pilot[0]);
// fgSetFloat("/sim/view/pilot/y-offset-m", -pilot[1]);
// fgSetFloat("/sim/view/pilot/z-offset-m", pilot[2]);
// Blank the state, and copy in ours
State s;
m->setState(&s);
copyToYASim(true);
_fdm->getExternalInput();
_fdm->getAirplane()->initEngines();
set_inited(true);
}
void YASim::update(double dt)
{
if (is_suspended())
return;
int iterations = _calc_multiloop(dt);
// If we're crashed, then we don't care
if(_fdm->getAirplane()->getModel()->isCrashed())
return;
int i;
for(i=0; i<iterations; i++) {
copyToYASim(false);
_fdm->iterate(_dt);
copyFromYASim();
printDEBUG();
}
}
void YASim::copyToYASim(bool copyState)
{
// Physical state
float lat = get_Latitude();
float lon = get_Longitude();
float alt = get_Altitude() * FT2M;
float roll = get_Phi();
float pitch = get_Theta();
float hdg = get_Psi();
// Environment
float wind[3];
wind[0] = get_V_north_airmass() * FT2M * -1.0;
wind[1] = get_V_east_airmass() * FT2M * -1.0;
wind[2] = get_V_down_airmass() * FT2M * -1.0;
// Get ground elevation from the FGinterface's FGlocation data
double ground = getACModel()->get3DModel()->getFGLocation()->get_cur_elev_m();
// cout << "YASIM: ground = " << ground << endl;
float pressure = fgGetDouble("/environment/pressure-inhg") * INHG2PA;
float temp = fgGetDouble("/environment/temperature-degC") + 273.15;
// Convert and set:
Model* model = _fdm->getAirplane()->getModel();
State s;
float xyz2ned[9];
Glue::xyz2nedMat(lat, lon, xyz2ned);
// position
Glue::geod2xyz(lat, lon, alt, s.pos);
// orientation
Glue::euler2orient(roll, pitch, hdg, s.orient);
Math::mmul33(s.orient, xyz2ned, s.orient);
// Copy in the existing velocity for now...
Math::set3(model->getState()->v, s.v);
if(copyState)
model->setState(&s);
// wind
Math::tmul33(xyz2ned, wind, wind);
model->setWind(wind);
// ground. Calculate a cartesian coordinate for the ground under
// us, find the (geodetic) up vector normal to the ground, then
// use that to find the final (radius) term of the plane equation.
double xyz[3], gplane[3]; float up[3];
Glue::geod2xyz(lat, lon, ground, xyz);
Glue::geodUp(xyz, up); // FIXME, needless reverse computation...
int i;
for(i=0; i<3; i++) gplane[i] = up[i];
double rad = gplane[0]*xyz[0] + gplane[1]*xyz[1] + gplane[2]*xyz[2];
model->setGroundPlane(gplane, rad);
// air
model->setAir(pressure, temp);
}
// All the settables:
//
// These are set below:
// _set_Accels_Local
// _set_Accels_Body
// _set_Accels_CG_Body
// _set_Accels_Pilot_Body
// _set_Accels_CG_Body_N
// _set_Velocities_Local
// _set_Velocities_Ground
// _set_Velocities_Wind_Body
// _set_Omega_Body
// _set_Euler_Rates
// _set_Euler_Angles
// _set_V_rel_wind
// _set_V_ground_speed
// _set_V_equiv_kts
// _set_V_calibrated_kts
// _set_Alpha
// _set_Beta
// _set_Mach_number
// _set_Climb_Rate
// _set_Tank1Fuel
// _set_Tank2Fuel
// _set_Altitude_AGL
// _set_Geodetic_Position
// _set_Runway_altitude
// Ignoring these, because they're unused:
// _set_Geocentric_Position
// _set_Geocentric_Rates
// _set_Cos_phi
// _set_Cos_theta
// _set_Earth_position_angle (WTF?)
// _set_Gamma_vert_rad
// _set_Inertias
// _set_T_Local_to_Body
// _set_CG_Position
// _set_Sea_Level_Radius
// Externally set via the weather code:
// _set_Velocities_Local_Airmass
// _set_Density
// _set_Static_pressure
// _set_Static_temperature
void YASim::copyFromYASim()
{
Airplane* airplane = _fdm->getAirplane();
Model* model = airplane->getModel();
State* s = model->getState();
// position
double lat, lon, alt;
Glue::xyz2geod(s->pos, &lat, &lon, &alt);
_set_Geodetic_Position(lat, lon, alt*M2FT);
// UNUSED
//_set_Geocentric_Position(Glue::geod2geocLat(lat), lon, alt*M2FT);
_set_Altitude_AGL(model->getAGL() * M2FT);
// useful conversion matrix
float xyz2ned[9];
Glue::xyz2nedMat(lat, lon, xyz2ned);
// velocity
float v[3];
Math::vmul33(xyz2ned, s->v, v);
_set_Velocities_Local(M2FT*v[0], M2FT*v[1], M2FT*v[2]);
_set_V_ground_speed(Math::sqrt(M2FT*v[0]*M2FT*v[0] +
M2FT*v[1]*M2FT*v[1]));
_set_Climb_Rate(-M2FT*v[2]);
// The HUD uses this, but inverts down (?!)
_set_Velocities_Ground(M2FT*v[0], M2FT*v[1], -M2FT*v[2]);
// _set_Geocentric_Rates(M2FT*v[0], M2FT*v[1], M2FT*v[2]); // UNUSED
// Airflow velocity.
float wind[3];
wind[0] = get_V_north_airmass() * FT2M * -1.0; // Wind in NED
wind[1] = get_V_east_airmass() * FT2M * -1.0;
wind[2] = get_V_down_airmass() * FT2M * -1.0;
Math::tmul33(xyz2ned, wind, wind); // Wind in global
Math::sub3(s->v, wind, v); // V - wind in global
Math::vmul33(s->orient, s->v, v); // to body coordinates
_set_Velocities_Wind_Body(v[0]*M2FT, -v[1]*M2FT, -v[2]*M2FT);
_set_V_rel_wind(Math::mag3(v)*M2FT); // units?
float P = fgGetDouble("/environment/pressure-inhg") * INHG2PA;
float T = fgGetDouble("/environment/temperature-degC") + 273.15;
_set_V_equiv_kts(Atmosphere::calcVEAS(v[0], P, T)*MPS2KTS);
_set_V_calibrated_kts(Atmosphere::calcVCAS(v[0], P, T)*MPS2KTS);
_set_Mach_number(Atmosphere::calcMach(v[0], T));
// acceleration
Math::vmul33(xyz2ned, s->acc, v);
_set_Accels_Local(M2FT*v[0], M2FT*v[1], M2FT*v[2]);
Math::vmul33(s->orient, s->acc, v);
_set_Accels_Body(M2FT*v[0], -M2FT*v[1], -M2FT*v[2]);
_set_Accels_CG_Body(M2FT*v[0], -M2FT*v[1], -M2FT*v[2]);
_fdm->getAirplane()->getPilotAccel(v);
_set_Accels_Pilot_Body(M2FT*v[0], M2FT*v[1], -M2FT*v[2]);
// The one appears (!) to want inverted pilot acceleration
// numbers, in G's...
Math::mul3(1.0/9.8, v, v);
_set_Accels_CG_Body_N(v[0], -v[1], -v[2]);
// orientation
float alpha, beta;
Glue::calcAlphaBeta(s, &alpha, &beta);
_set_Alpha(alpha);
_set_Beta(beta);
float tmp[9];
Math::trans33(xyz2ned, tmp);
Math::mmul33(s->orient, tmp, tmp);
float roll, pitch, hdg;
Glue::orient2euler(tmp, &roll, &pitch, &hdg);
_set_Euler_Angles(roll, pitch, hdg);
// rotation
Math::vmul33(s->orient, s->rot, v);
_set_Omega_Body(v[0], -v[1], -v[2]);
Glue::calcEulerRates(s, &roll, &pitch, &hdg);
_set_Euler_Rates(roll, pitch, hdg);
// Fill out our engine and gear objects
int i;
for(i=0; i<airplane->numGear(); i++) {
Gear* g = airplane->getGear(i);
SGPropertyNode * node = fgGetNode("gear/gear", i, true);
node->setBoolValue("has-brake", g->getBrake() != 0);
node->setBoolValue("wow", g->getCompressFraction() != 0);
node->setFloatValue("compression-norm", g->getCompressFraction());
}
for(i=0; i<model->numThrusters(); i++) {
SGPropertyNode * node = fgGetNode("engines/engine", i, true);
Thruster* t = model->getThruster(i);
node->setBoolValue("running", t->isRunning());
node->setBoolValue("cranking", t->isCranking());
// Note: assumes all tanks have the same fuel density!
node->setDoubleValue("fuel-flow-gph", CM2GALS * t->getFuelFlow()
/ airplane->getFuelDensity(0));
float tmp[3];
t->getThrust(tmp);
node->setDoubleValue("prop-thrust", Math::mag3(tmp) * KG2LBS / 9.8);
PropEngine* pe = t->getPropEngine();
if(pe) {
node->setDoubleValue("rpm", pe->getOmega() * RAD2RPM);
pe->getTorque(tmp);
float power = Math::mag3(tmp) * pe->getOmega();
float maxPower = pe->getPistonEngine()->getMaxPower();
node->setDoubleValue("max-hp", maxPower * W2HP);
node->setDoubleValue("power-pct", 100 * power/maxPower);
}
}
}
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