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flightgear/src/FDM/YASim/FGFDM.cpp

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#include <stdio.h>
#include <stdlib.h>
#include <Main/fg_props.hxx>
#include "Jet.hpp"
#include "SimpleJet.hpp"
#include "Gear.hpp"
#include "Atmosphere.hpp"
#include "PropEngine.hpp"
#include "Propeller.hpp"
#include "PistonEngine.hpp"
#include "FGFDM.hpp"
namespace yasim {
// Some conversion factors
static const float KTS2MPS = 0.514444444444;
static const float FT2M = 0.3048;
static const float DEG2RAD = 0.0174532925199;
static const float RPM2RAD = 0.10471975512;
static const float LBS2N = 4.44822;
static const float LBS2KG = 0.45359237;
static const float CM2GALS = 264.172037284;
static const float HP2W = 745.700;
static const float INHG2PA = 3386.389;
static const float K2DEGF = 1.8;
static const float CIN2CM = 1.6387064e-5;
// Stubs, so that this can be compiled without the FlightGear
// binary. What's the best way to handle this?
// float fgGetFloat(char* name, float def) { return 0; }
// void fgSetFloat(char* name, float val) {}
FGFDM::FGFDM()
{
_nextEngine = 0;
}
FGFDM::~FGFDM()
{
int i;
for(i=0; i<_axes.size(); i++) {
AxisRec* a = (AxisRec*)_axes.get(i);
delete[] a->name;
delete a;
}
for(i=0; i<_thrusters.size(); i++) {
EngRec* er = (EngRec*)_thrusters.get(i);
delete[] er->prefix;
delete er->eng;
delete er;
}
for(i=0; i<_weights.size(); i++) {
WeightRec* wr = (WeightRec*)_weights.get(i);
delete[] wr->prop;
delete wr;
}
for(i=0; i<_controlProps.size(); i++)
delete (PropOut*)_controlProps.get(i);
}
void FGFDM::iterate(float dt)
{
getExternalInput(dt);
_airplane.iterate(dt);
setOutputProperties();
}
Airplane* FGFDM::getAirplane()
{
return &_airplane;
}
void FGFDM::init()
{
// Allows the user to start with something other than full fuel
_airplane.setFuelFraction(fgGetFloat("/sim/fuel-fraction", 1));
// This has a nasty habit of being false at startup. That's not
// good.
fgSetBool("/controls/gear-down", true);
}
// Not the worlds safest parser. But it's short & sweet.
void FGFDM::startElement(const char* name, const XMLAttributes &atts)
{
XMLAttributes* a = (XMLAttributes*)&atts;
float v[3];
char buf[64];
if(eq(name, "airplane")) {
_airplane.setWeight(attrf(a, "mass") * LBS2KG);
} else if(eq(name, "approach")) {
float spd = attrf(a, "speed") * KTS2MPS;
float alt = attrf(a, "alt", 0) * FT2M;
float aoa = attrf(a, "aoa", 0) * DEG2RAD;
_airplane.setApproach(spd, alt, aoa);
_cruiseCurr = false;
} else if(eq(name, "cruise")) {
float spd = attrf(a, "speed") * KTS2MPS;
float alt = attrf(a, "alt") * FT2M;
_airplane.setCruise(spd, alt);
_cruiseCurr = true;
} else if(eq(name, "cockpit")) {
v[0] = attrf(a, "x");
v[1] = attrf(a, "y");
v[2] = attrf(a, "z");
_airplane.setPilotPos(v);
} else if(eq(name, "wing")) {
_airplane.setWing(parseWing(a, name));
} else if(eq(name, "hstab")) {
_airplane.setTail(parseWing(a, name));
} else if(eq(name, "vstab")) {
_airplane.addVStab(parseWing(a, name));
} else if(eq(name, "propeller")) {
parsePropeller(a);
} else if(eq(name, "thruster")) {
SimpleJet* j = new SimpleJet();
_currObj = j;
v[0] = attrf(a, "x"); v[1] = attrf(a, "y"); v[2] = attrf(a, "z");
j->setPosition(v);
_airplane.addThruster(j, 0, v);
v[0] = attrf(a, "vx"); v[1] = attrf(a, "vy"); v[2] = attrf(a, "vz");
j->setDirection(v);
j->setThrust(attrf(a, "thrust") * LBS2N);
} else if(eq(name, "jet")) {
Jet* j = new Jet();
_currObj = j;
v[0] = attrf(a, "x");
v[1] = attrf(a, "y");
v[2] = attrf(a, "z");
float mass = attrf(a, "mass") * LBS2KG;
j->setMaxThrust(attrf(a, "thrust") * LBS2N,
attrf(a, "afterburner", 0) * LBS2N);
j->setVectorAngle(attrf(a, "rotate", 0) * DEG2RAD);
float n1min = attrf(a, "n1-idle", 55);
float n1max = attrf(a, "n1-max", 102);
float n2min = attrf(a, "n2-idle", 73);
float n2max = attrf(a, "n2-max", 103);
j->setRPMs(n1min, n1max, n2min, n2max);
if(a->hasAttribute("tsfc")) j->setTSFC(attrf(a, "tsfc"));
if(a->hasAttribute("egt")) j->setEGT(attrf(a, "egt"));
if(a->hasAttribute("epr")) j->setEPR(attrf(a, "epr"));
if(a->hasAttribute("exhaust-speed"))
j->setVMax(attrf(a, "exhaust-speed") * KTS2MPS);
j->setPosition(v);
_airplane.addThruster(j, mass, v);
sprintf(buf, "/engines/engine[%d]", _nextEngine++);
EngRec* er = new EngRec();
er->eng = j;
er->prefix = dup(buf);
_thrusters.add(er);
} else if(eq(name, "gear")) {
Gear* g = new Gear();
_currObj = g;
v[0] = attrf(a, "x");
v[1] = attrf(a, "y");
v[2] = attrf(a, "z");
g->setPosition(v);
v[0] = 0;
v[1] = 0;
v[2] = attrf(a, "compression", 1);
g->setCompression(v);
g->setBrake(attrf(a, "skid", 0));
g->setStaticFriction(attrf(a, "sfric", 0.8));
g->setDynamicFriction(attrf(a, "dfric", 0.7));
if(a->hasAttribute("castering"))
g->setCastering(true);
_airplane.addGear(g);
} else if(eq(name, "fuselage")) {
float b[3];
v[0] = attrf(a, "ax");
v[1] = attrf(a, "ay");
v[2] = attrf(a, "az");
b[0] = attrf(a, "bx");
b[1] = attrf(a, "by");
b[2] = attrf(a, "bz");
float taper = attrf(a, "taper", 1);
float mid = attrf(a, "midpoint", 0.5);
_airplane.addFuselage(v, b, attrf(a, "width"), taper, mid);
} else if(eq(name, "tank")) {
v[0] = attrf(a, "x");
v[1] = attrf(a, "y");
v[2] = attrf(a, "z");
float density = 6.0; // gasoline, in lbs/gal
if(a->hasAttribute("jet")) density = 6.72;
density *= LBS2KG*CM2GALS;
_airplane.addTank(v, attrf(a, "capacity") * LBS2KG, density);
} else if(eq(name, "ballast")) {
v[0] = attrf(a, "x");
v[1] = attrf(a, "y");
v[2] = attrf(a, "z");
_airplane.addBallast(v, attrf(a, "mass") * LBS2KG);
} else if(eq(name, "weight")) {
parseWeight(a);
} else if(eq(name, "stall")) {
Wing* w = (Wing*)_currObj;
w->setStall(attrf(a, "aoa") * DEG2RAD);
w->setStallWidth(attrf(a, "width", 2) * DEG2RAD);
w->setStallPeak(attrf(a, "peak", 1.5));
} else if(eq(name, "flap0")) {
((Wing*)_currObj)->setFlap0(attrf(a, "start"), attrf(a, "end"),
attrf(a, "lift"), attrf(a, "drag"));
} else if(eq(name, "flap1")) {
((Wing*)_currObj)->setFlap1(attrf(a, "start"), attrf(a, "end"),
attrf(a, "lift"), attrf(a, "drag"));
} else if(eq(name, "slat")) {
((Wing*)_currObj)->setSlat(attrf(a, "start"), attrf(a, "end"),
attrf(a, "aoa"), attrf(a, "drag"));
} else if(eq(name, "spoiler")) {
((Wing*)_currObj)->setSpoiler(attrf(a, "start"), attrf(a, "end"),
attrf(a, "lift"), attrf(a, "drag"));
} else if(eq(name, "actionpt")) {
v[0] = attrf(a, "x");
v[1] = attrf(a, "y");
v[2] = attrf(a, "z");
((Thruster*)_currObj)->setPosition(v);
} else if(eq(name, "dir")) {
v[0] = attrf(a, "x");
v[1] = attrf(a, "y");
v[2] = attrf(a, "z");
((Thruster*)_currObj)->setDirection(v);
} else if(eq(name, "control-setting")) {
// A cruise or approach control setting
const char* axis = a->getValue("axis");
float value = attrf(a, "value", 0);
if(_cruiseCurr)
_airplane.addCruiseControl(parseAxis(axis), value);
else
_airplane.addApproachControl(parseAxis(axis), value);
} else if(eq(name, "control-input")) {
// A mapping of input property to a control
int axis = parseAxis(a->getValue("axis"));
int control = parseOutput(a->getValue("control"));
int opt = 0;
opt |= a->hasAttribute("split") ? ControlMap::OPT_SPLIT : 0;
opt |= a->hasAttribute("invert") ? ControlMap::OPT_INVERT : 0;
opt |= a->hasAttribute("square") ? ControlMap::OPT_SQUARE : 0;
ControlMap* cm = _airplane.getControlMap();
if(a->hasAttribute("src0")) {
cm->addMapping(axis, control, _currObj, opt,
attrf(a, "src0"), attrf(a, "src1"),
attrf(a, "dst0"), attrf(a, "dst1"));
} else {
cm->addMapping(axis, control, _currObj, opt);
}
} else if(eq(name, "control-output")) {
// A property output for a control on the current object
ControlMap* cm = _airplane.getControlMap();
int type = parseOutput(a->getValue("control"));
int handle = cm->getOutputHandle(_currObj, type);
PropOut* p = new PropOut();
p->prop = fgGetNode(a->getValue("prop"), true);
p->handle = handle;
p->type = type;
p->left = !(a->hasAttribute("side") &&
eq("right", a->getValue("side")));
p->min = attrf(a, "min", cm->rangeMin(type));
p->max = attrf(a, "max", cm->rangeMax(type));
_controlProps.add(p);
} else if(eq(name, "control-speed")) {
ControlMap* cm = _airplane.getControlMap();
int type = parseOutput(a->getValue("control"));
int handle = cm->getOutputHandle(_currObj, type);
float time = attrf(a, "transition-time", 0);
cm->setTransitionTime(handle, time);
} else {
SG_LOG(SG_FLIGHT,SG_ALERT,"Unexpected tag '"
<< name << "' found in YASim aircraft description");
exit(1);
}
}
void FGFDM::getExternalInput(float dt)
{
// The control axes
ControlMap* cm = _airplane.getControlMap();
cm->reset();
int i;
for(i=0; i<_axes.size(); i++) {
AxisRec* a = (AxisRec*)_axes.get(i);
float val = fgGetFloat(a->name, 0);
cm->setInput(a->handle, val);
}
cm->applyControls(dt);
// Weights
for(i=0; i<_weights.size(); i++) {
WeightRec* wr = (WeightRec*)_weights.get(i);
_airplane.setWeight(wr->handle, fgGetFloat(wr->prop));
}
}
void FGFDM::setOutputProperties()
{
char buf[256];
int i;
ControlMap* cm = _airplane.getControlMap();
for(i=0; i<_controlProps.size(); i++) {
PropOut* p = (PropOut*)_controlProps.get(i);
float val = (p->left
? cm->getOutput(p->handle)
: cm->getOutputR(p->handle));
float rmin = cm->rangeMin(p->type);
float rmax = cm->rangeMax(p->type);
float frac = (val - rmin) / (rmax - rmin);
val = frac*(p->max - p->min) + p->min;
p->prop->setFloatValue(val);
}
float fuelDensity = 718.95; // default to gasoline: ~6 lb/gal
for(i=0; i<_airplane.numTanks(); i++) {
fuelDensity = _airplane.getFuelDensity(i);
sprintf(buf, "/consumables/fuel/tank[%d]/level-gal_us", i);
fgSetFloat(buf, CM2GALS*_airplane.getFuel(i)/fuelDensity);
}
for(i=0; i<_thrusters.size(); i++) {
EngRec* er = (EngRec*)_thrusters.get(i);
Thruster* t = er->eng;
sprintf(buf, "%s/fuel-flow-gph", er->prefix);
fgSetFloat(buf, (t->getFuelFlow()/fuelDensity) * 3600 * CM2GALS);
if(t->getPropEngine()) {
PropEngine* p = t->getPropEngine();
sprintf(buf, "%s/rpm", er->prefix);
fgSetFloat(buf, p->getOmega() / RPM2RAD);
}
if(t->getPistonEngine()) {
PistonEngine* p = t->getPistonEngine();
sprintf(buf, "%s/mp-osi", er->prefix);
fgSetFloat(buf, p->getMP() * (1/INHG2PA));
sprintf(buf, "%s/egt-degf", er->prefix);
fgSetFloat(buf, p->getEGT() * K2DEGF + 459.4);
}
if(t->getJet()) {
Jet* j = t->getJet();
sprintf(buf, "%s/n1", er->prefix);
fgSetFloat(buf, j->getN1());
sprintf(buf, "%s/n2", er->prefix);
fgSetFloat(buf, j->getN2());
sprintf(buf, "%s/epr", er->prefix);
fgSetFloat(buf, j->getEPR());
sprintf(buf, "%s/egt-degf", er->prefix);
fgSetFloat(buf, j->getEGT() * K2DEGF + 459.4);
}
}
}
Wing* FGFDM::parseWing(XMLAttributes* a, const char* type)
{
Wing* w = new Wing();
float defDihed = 0;
if(eq(type, "vstab"))
defDihed = 90;
else
w->setMirror(true);
float pos[3];
pos[0] = attrf(a, "x");
pos[1] = attrf(a, "y");
pos[2] = attrf(a, "z");
w->setBase(pos);
w->setLength(attrf(a, "length"));
w->setChord(attrf(a, "chord"));
w->setSweep(attrf(a, "sweep", 0) * DEG2RAD);
w->setTaper(attrf(a, "taper", 1));
w->setDihedral(attrf(a, "dihedral", defDihed) * DEG2RAD);
w->setCamber(attrf(a, "camber", 0));
w->setIncidence(attrf(a, "incidence", 0) * DEG2RAD);
float effect = attrf(a, "effectiveness", 1);
w->setDragScale(w->getDragScale()*effect);
_currObj = w;
return w;
}
void FGFDM::parsePropeller(XMLAttributes* a)
{
float cg[3];
cg[0] = attrf(a, "x");
cg[1] = attrf(a, "y");
cg[2] = attrf(a, "z");
float mass = attrf(a, "mass") * LBS2KG;
float moment = attrf(a, "moment");
float radius = attrf(a, "radius");
float speed = attrf(a, "cruise-speed") * KTS2MPS;
float omega = attrf(a, "cruise-rpm") * RPM2RAD;
float power = attrf(a, "cruise-power") * HP2W;
float rho = Atmosphere::getStdDensity(attrf(a, "cruise-alt") * FT2M);
// Hack, fix this pronto:
float engP = attrf(a, "eng-power") * HP2W;
float engS = attrf(a, "eng-rpm") * RPM2RAD;
Propeller* prop = new Propeller(radius, speed, omega, rho, power);
PistonEngine* eng = new PistonEngine(engP, engS);
PropEngine* thruster = new PropEngine(prop, eng, moment);
_airplane.addThruster(thruster, mass, cg);
if(a->hasAttribute("displacement"))
eng->setDisplacement(attrf(a, "displacement") * CIN2CM);
if(a->hasAttribute("compression"))
eng->setCompression(attrf(a, "compression"));
if(a->hasAttribute("turbo-mul")) {
float mul = attrf(a, "turbo-mul");
float mp = attrf(a, "wastegate-mp", 1e6) * INHG2PA;
eng->setTurboParams(mul, mp);
}
if(a->hasAttribute("takeoff-power")) {
float power0 = attrf(a, "takeoff-power") * HP2W;
float omega0 = attrf(a, "takeoff-rpm") * RPM2RAD;
prop->setTakeoff(omega0, power0);
}
if(a->hasAttribute("max-rpm")) {
float max = attrf(a, "max-rpm") * RPM2RAD;
float min = attrf(a, "min-rpm") * RPM2RAD;
thruster->setVariableProp(min, max);
}
char buf[64];
sprintf(buf, "/engines/engine[%d]", _nextEngine++);
EngRec* er = new EngRec();
er->eng = thruster;
er->prefix = dup(buf);
_thrusters.add(er);
_currObj = thruster;
}
// Turns a string axis name into an integer for use by the
// ControlMap. Creates a new axis if this one hasn't been defined
// yet.
int FGFDM::parseAxis(const char* name)
{
int i;
for(i=0; i<_axes.size(); i++) {
AxisRec* a = (AxisRec*)_axes.get(i);
if(eq(a->name, name))
return a->handle;
}
// Not there, make a new one.
AxisRec* a = new AxisRec();
a->name = dup(name);
a->handle = _airplane.getControlMap()->newInput();
_axes.add(a);
return a->handle;
}
int FGFDM::parseOutput(const char* name)
{
if(eq(name, "THROTTLE")) return ControlMap::THROTTLE;
if(eq(name, "MIXTURE")) return ControlMap::MIXTURE;
if(eq(name, "STARTER")) return ControlMap::STARTER;
if(eq(name, "MAGNETOS")) return ControlMap::MAGNETOS;
if(eq(name, "ADVANCE")) return ControlMap::ADVANCE;
if(eq(name, "REHEAT")) return ControlMap::REHEAT;
if(eq(name, "BOOST")) return ControlMap::BOOST;
if(eq(name, "VECTOR")) return ControlMap::VECTOR;
if(eq(name, "PROP")) return ControlMap::PROP;
if(eq(name, "BRAKE")) return ControlMap::BRAKE;
if(eq(name, "STEER")) return ControlMap::STEER;
if(eq(name, "EXTEND")) return ControlMap::EXTEND;
if(eq(name, "INCIDENCE")) return ControlMap::INCIDENCE;
if(eq(name, "FLAP0")) return ControlMap::FLAP0;
if(eq(name, "FLAP1")) return ControlMap::FLAP1;
if(eq(name, "SLAT")) return ControlMap::SLAT;
if(eq(name, "SPOILER")) return ControlMap::SPOILER;
SG_LOG(SG_FLIGHT,SG_ALERT,"Unrecognized control type '"
<< name << "' in YASim aircraft description.");
exit(1);
}
void FGFDM::parseWeight(XMLAttributes* a)
{
WeightRec* wr = new WeightRec();
float v[3];
v[0] = attrf(a, "x");
v[1] = attrf(a, "y");
v[2] = attrf(a, "z");
wr->prop = dup(a->getValue("mass-prop"));
wr->size = attrf(a, "size", 0);
wr->handle = _airplane.addWeight(v, wr->size);
_weights.add(wr);
}
bool FGFDM::eq(const char* a, const char* b)
{
// Figure it out for yourself. :)
while(*a && *b && *a == *b) { a++; b++; }
return !(*a || *b);
}
char* FGFDM::dup(const char* s)
{
int len=0;
while(s[len++]);
char* s2 = new char[len+1];
char* p = s2;
while((*p++ = *s++));
s2[len] = 0;
return s2;
}
int FGFDM::attri(XMLAttributes* atts, char* attr)
{
if(!atts->hasAttribute(attr)) {
SG_LOG(SG_FLIGHT,SG_ALERT,"Missing '" << attr <<
"' in YASim aircraft description");
exit(1);
}
return attri(atts, attr, 0);
}
int FGFDM::attri(XMLAttributes* atts, char* attr, int def)
{
const char* val = atts->getValue(attr);
if(val == 0) return def;
else return atol(val);
}
float FGFDM::attrf(XMLAttributes* atts, char* attr)
{
if(!atts->hasAttribute(attr)) {
SG_LOG(SG_FLIGHT,SG_ALERT,"Missing '" << attr <<
"' in YASim aircraft description");
exit(1);
}
return attrf(atts, attr, 0);
}
float FGFDM::attrf(XMLAttributes* atts, char* attr, float def)
{
const char* val = atts->getValue(attr);
if(val == 0) return def;
else return (float)atof(val);
}
}; // namespace yasim
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